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Sample records for affected zone southern

  1. Low VS crustal zones in the Campanian Plain (Southern Italy)

    Science.gov (United States)

    Nunziata, Concettina; Costanzo, Maria Rosaria

    2010-11-01

    Shear wave velocities of the lithospheric structure to 73 km depth have been defined along three profiles crossing the Campanian Plain (Southern Italy) from the simultaneous non linear inversion of the local and regional dispersion data. The former consist of group velocity dispersion data obtained from some seismic events which occurred at the borders of the Campanian Plain and recorded at Napoli, and the latter of group and phase dispersion data obtained in previous studies. The main features of the representative VS models are a carbonate basement deepening to ˜5 km in the central part of the Plain and a low velocity zone at a depth of ˜15 km, rising to 7 km in the southern part, close to Somma-Vesuvio. The low velocity layer can be correlated with that found at ˜10 km of depth below Campi Flegrei and the Neapolitan area, and at 5 km below the Somma-Vesuvio caldera area. Such regional velocity reduction can be associated to the presence of a zone with less than 5% partial melting that can be interpreted as magmatic reservoir of the Campanian volcanism.

  2. Hydraulic structure of a fault zone at seismogenic depths (Gole Larghe Fault Zone, Italian Southern Alps)

    Science.gov (United States)

    Bistacchi, Andrea; Mittempergher, Silvia; Di Toro, Giulio; Smith, Steve; Garofalo, Paolo; Vho, Alice

    2016-04-01

    The Gole Larghe Fault Zone (GLFZ, Italian Southern Alps) was exhumed from c. 8 km depth, where it was characterized by seismic activity (pseudotachylytes), but also by hydrous fluid flow (alteration halos and precipitation of hydrothermal minerals in veins and cataclasites). Thanks to glacier-polished outcrops exposing the fault zone over a continuous area > 1 km2, the fault zone architecture has been quantitatively described with an unprecedented detail (Bistacchi 2011, PAGEOPH; Smith 2013, JSG; Mittempergher 2016, this meeting), providing a rich dataset to generate 3D Discrete Fracture Network (DFN) models and simulate the fault zone hydraulic properties. Based on field and microstructural evidence, we infer that the opening and closing of fractures resulted in a toggle-switch mechanism for fluid flow during the seismic cycle: higher permeability was obtained in the syn- to early post-seismic period, when the largest number of fractures was (re)opened by off-fault deformation, then permeability dropped due to hydrothermal mineral precipitation and fracture sealing. Since the fracture network that we observe now in the field is the result of the cumulative deformation history of the fault zone, which probably includes thousands of earthquakes, a fundamental parameter that cannot be directly evaluated in the field is the fraction of fractures-faults that were open immediately after a single earthquake. Postseismic permeability has been evaluated in a few cases in the world thanks to seismological evidences of fluid migration along active fault systems. Therefore, we were able to develop a parametric hydraulic model of the GLFZ and calibrate it, varying the fraction of faults/fractures that were open in the postseismic period, to obtain on one side realistic fluid flow and permeability values, and on the other side a flow pattern consistent with the observed alteration/mineralization pattern. The fraction of open fractures is very close to the percolation threshold

  3. Factors Affecting Patients Undergoing Cosmetic Surgery in Bushehr, Southern Iran

    OpenAIRE

    Salehahmadi, Zeinab; Rafie, Seyyed Reza

    2012-01-01

    BACKGROUND Although, there have been extensive research on the motivations driving patient to undergo cosmetic procedures, there is still a big question mark on the persuasive factors which may lead individuals to undergo cosmetic surgery. The present study evaluated various factors affecting patients undergoing cosmetic surgery in Bushehr, Southern Iran. METHODS From 24th March 2011 to 24th March 2012, eighty-one women and 20 men who wished to be operated in Fatemeh Zahra Hospital in Bushehr...

  4. Behaviour of nitrogen in the unsaturated zone in Southern Africa

    International Nuclear Information System (INIS)

    Large areas in southern Africa have high levels of nitrate (>50 mg N/L) in groundwater caused either by natural nitrogen fixation or by pollution. Certain environmental conditions such as episodic groundwater recharge enhance such high levels and increase its variability. Soil samples were taken from two entirely different sites to identify sources and transport of nitrate through the soil. In arid Botswana, occasional high nitrate pulses with distinct pollution 15N signatures are observed in groundwater following extreme rainfall events. These are thought to result from a combination of regular recharge along preferential flow paths and rapid recharge through unleached soils during episodic recharge in this area. Soil samples down to 3 metres in different environments showed the usual vertical decrease of nitrate in both polluted and natural environments. One profile collecting outwash from a large polluted area showed an increase of nitrate and chloride with depth and represents a situation where episodes of rapid flushing of pollutant nitrate towards the water table may be expected. In humid sandy soils near Cape Town, South Africa, a comparison was made between soils from a reference area covered by leguminous vegetation and from an adjacent agricultural land previously fertilised with sewage sludge. The soil in the reference area was drier due to deeper moisture withdrawal by trees. In the agricultural land constant ammonia levels occur throughout the depth profile while nitrate levels decrease with depth. 15N levels in ammonia increase towards the water table, while 15N levels in nitrate remains practically constant with depth. These profiles show the recovery effect of the vadose zone after sludge deposition on the surface was discontinued. Considering both profiles, the results show the different responses that are possible under widely varying conditions of recharge and pollution load and link up with the chemical and isotope content of groundwater

  5. Seabed pockmarks in the southern Bulgarian Black Sea zone

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrov, L.I. (Laboratory of Marine Geophysics, Varna (Bulgaria)); Dontcheva, V.G. (Department of Marine Geology Institute of Oceanology, Varna (Bulgaria))

    1994-03-01

    Pockmarks were discovered for the first time in the SE of the Bulgarian Black Sea zone in 1988. Echo sounder and shallow seismic data analyses of investigations conducted before and after 1988, allow the main pockmark area to be enlarged and given more details. A total of 305 pockmarks have been located within an area of more than 100 km[sup 2] (2-5 km wide and 41 km long). The bottom of the area is covered with holocene soft silty clay. The following trends are defined when moving from the northern part of the pockmark area to the southern part: (1) increase in seabed sediments thickness from 2.5 m to more than 3.2 m and decrease in mean sediment grain size; (2) increase in general water depth from 160-300 m to 230-340 m in areas where pockmarks occur; (3) increase in average individual pockmark size from 86 to 132 m in diameter and from 2 to 4 m in depth; (4) decrease of pockmark density from 8-9 p.m./km[sup 2] to 3-4 p.m./km[sup 2]. Similar trends are observed seaward where the pockmark profile shape change from a smooth U-shaped to a sharp V-shaped form, with pockmark wall slope angle reaching more than 10 deg. A variety of acoustic anomalies such as acoustic turbidity, bright spots, enhanced reflections etc., are recorded in many places within the pockmark area, indicating the presence of gas in the sediments. Water column anomalies have also been recorded. The paper discusses the origin of the gas (most likely to be a mixture of thermogenic and biogenic gas) and the time of pockmark formation. (au) (21 refs.)

  6. Root-Zone Glyphosate Exposure Adversely Affects Two Ditch Species

    Directory of Open Access Journals (Sweden)

    Lyndsay E. Saunders

    2013-12-01

    Full Text Available Glyphosate, one of the most applied herbicides globally, has been extensively studied for its effects on non-target organisms. In the field, following precipitation, glyphosate runs off into agricultural ditches where it infiltrates into the soil and thus may encounter the roots of vegetation. These edge-of-field ditches share many characteristics with wetlands, including the ability to reduce loads of anthropogenic chemicals through uptake, transformation, and retention. Different species within the ditches may have a differential sensitivity to exposure of the root zone to glyphosate, contributing to patterns of abundance of ruderal species. The present laboratory experiment investigated whether two species commonly found in agricultural ditches in southcentral United States were affected by root zone glyphosate in a dose-dependent manner, with the objective of identifying a sublethal concentration threshold. The root zone of individuals of Polygonum hydropiperoides and Panicum hemitomon were exposed to four concentrations of glyphosate. Leaf chlorophyll content was measured, and the ratio of aboveground biomass to belowground biomass and survival were quantified. The findings from this study showed that root zone glyphosate exposure negatively affected both species including dose-dependent reductions in chlorophyll content. P. hydropiperdoides showed the greatest negative response, with decreased belowground biomass allocation and total mortality at the highest concentrations tested.

  7. Mechanical Properties of Heat Affected Zone of High Strength Steels

    Science.gov (United States)

    Sefcikova, K.; Brtnik, T.; Dolejs, J.; Keltamaki, K.; Topilla, R.

    2015-11-01

    High Strength Steels became more popular as a construction material during last decade because of their increased availability and affordability. On the other hand, even though general use of Advanced High Strength Steels (AHSS) is expanding, the wide utilization is limited because of insufficient information about their behaviour in structures. The most widely used technique for joining steels is fusion welding. The welding process has an influence not only on the welded connection but on the area near this connection, the so-called heat affected zone, as well. For that reason it is very important to be able to determine the properties in the heat affected zone (HAZ). This area of investigation is being continuously developed in dependence on significant progress in material production, especially regarding new types of steels available. There are currently several types of AHSS on the world market. Two most widely used processes for AHSS production are Thermo-Mechanically Controlled Processing (TMCP) and Quenching in connection with Tempering. In the presented study, TMCP and QC steels grade S960 were investigated. The study is focused on the changes of strength, ductility, hardness and impact strength in heat affected zone based on the used amount of heat input.

  8. Lower crustal intrusions beneath the southern Baikal Rift Zone

    DEFF Research Database (Denmark)

    Nielsen, Christoffer; Thybo, Hans

    2009-01-01

    The Cenozoic Baikal Rift Zone (BRZ) is situated in south-central Siberia in the suture between the Precambrian Siberian Platform and the Amurian plate. This more than 2000-km long rift zone is composed of several individual basement depressions and half-grabens with the deep Lake Baikal at its...... of the crust and uppermost mantle. Previous interpretation and velocity modelling of P-wave arrivals in the BEST data has revealed a multi layered crust with smooth variation in Moho depth between the Siberian Platform (41 km) and the Sayan-Baikal fold belt (46 km). The lower crust exhibits normal seismic...

  9. Groundwater fluctuations and footslope ferricrete soils in the humid tropical zone of southern Cameroon

    Science.gov (United States)

    Temgoua, Emile; Djeuda Tchapnga, Henri-Bosko; Tanawa, Emile; Guenat, Claire; Pfeifer, Hans-Rudolf

    2005-10-01

    This paper discusses the relationship between the differentiation of ferruginous accumulations and the variable water saturation of footslope soil patterns. An analysis of the slope morphology of a typical hill in the forest zone of southern Cameroon and a seasonal survey of the levels of groundwaters, springs and rivers were considered in relation to the petrology of different soil patterns. The study site is a tabular hillock whose slopes present a progressive development from steep to gentle slopes. The variable residence time of water within the soil, creating an alternation of reducing and oxidizing conditions, affects soil chemistry, structure and lateral extension of the soil patterns. The ferruginous soil patterns, being formed on the footslopes, gradually increase in extent with decreasing slope angle and the relative rise of the groundwater level. The steep footslopes, where groundwater has a shorter residence time, show a soft mottled clay pattern, restricted to the bottom part of the slope. The moderate footslopes exhibit a deep permanent and a temporary perched groundwater table. The latter, with its regular capillary fringe, contributes to more reducing conditions within isolated domains in the soil patterns, and thus to the alternation with oxidizing conditions, generating a continuous hard soil pattern (massive carapace). The more gently dipping footslopes exhibit groundwater levels near the surface and also a significant amplitude of groundwater fluctuation. Iron, previously accumulated in moderate footslope patterns, is reduced, remobilized, and leached. The soil patterns formed develop into a variegated carapace, more extended along the slope, containing less iron, but nevertheless more hardened, due to the important fluctuations of the groundwater table. These patterns are limited to the zone of groundwater fluctuation and deteriorate as the water fluctuation zone recedes.

  10. Paleoseismology of the Southern Section of the Black Mountains and Southern Death Valley Fault Zones, Death Valley, United States

    Science.gov (United States)

    Sohn, Marsha S.; Knott, Jeffrey R.; Mahan, Shannon

    2014-01-01

    The Death Valley Fault System (DVFS) is part of the southern Walker Lane–eastern California shear zone. The normal Black Mountains Fault Zone (BMFZ) and the right-lateral Southern Death Valley Fault Zone (SDVFZ) are two components of the DVFS. Estimates of late Pleistocene-Holocene slip rates and recurrence intervals for these two fault zones are uncertain owing to poor relative age control. The BMFZ southernmost section (Section 1W) steps basinward and preserves multiple scarps in the Quaternary alluvial fans. We present optically stimulated luminescence (OSL) dates ranging from 27 to 4 ka of fluvial and eolian sand lenses interbedded with alluvial-fan deposits offset by the BMFZ. By cross-cutting relations, we infer that there were three separate ground-rupturing earthquakes on BMFZ Section 1W with vertical displacement between 5.5 m and 2.75 m. The slip-rate estimate is ∼0.2 to 1.8 mm/yr, with an earthquake recurrence interval of 4,500 to 2,000 years. Slip-per-event measurements indicate Mw 7.0 to 7.2 earthquakes. The 27–4-ka OSL-dated alluvial fans also overlie the putative Cinder Hill tephra layer. Cinder Hill is offset ∼213 m by SDVFZ, which yields a tentative slip rate of 1 to 8 mm/yr for the SDVFZ.

  11. Phytoplankton and pigment patterns across frontal zones in the Atlantic sector of the Southern Ocean

    NARCIS (Netherlands)

    van Leeuwe, Maria A.; Kattner, Gerhard; van Oijen, Tim; de Jong, Jeroen T. M.; de Baar, Hein J.W.

    2015-01-01

    Phytoplankton distribution and concentrations of macronutrients and iron were studied in the Polar Frontal Zone (PFZ) and the eastern Weddell Gyre of the Southern Ocean, during austral autumn. HPLC analysis of algal pigments was combined with microscopy observations to assess algal distribution. Pat

  12. Triangle zone and displacement transfer structures in the eastern Front Ranges, southern Canadian Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Sanderson, D.A. (Petrel Robertson Ltd., Calgary, Alberta (Canada)); Spratt, D.A. (Univ. of Calgary, Alberta (Canada))

    1992-06-01

    The geometry of a relict triangle zone at the boundary of the Foothills and Front Ranges in the southern Canadian Rocky Mountains is constrained by detailed surface mapping over 700 m of relief and by seismic reflection data. The geometry and progressive development of the triangle zone along a strike length of 15-20 km, in the displacement transfer zone between the Coleman and Misty thrusts, is illustrated using closely spaced balanced cross sections, palinspastic restorations, and s sequentially restored cross section. Structural geometries show that a northeast- (foreland-) verging, mainly carbonate wedge of Mississippian to Triassic rock was inserted along a major upper detachment zone in shale, near the base of the Jurassic-Cretaceous clastic package. This was accompanied by southwest- (hinterland-) verging displacements along the upper detachment zone, tectonic thickening of the clastic package exceeding 200%, and backthrusting. Later northeast-verging deformation slightly modified the triangle zone by steepening structures, tightening folds, and minor thrusting. Recognition of relict triangle zones within the fold and thrust belt may document important changes in the rate of thrust front advancement, and aid in the delineation of potential hydrocarbon traps, similar to those discovered along the present-day thrust-belt margin in the southern Canadian Rocky Mountains.

  13. Characteristics of GTA fusion zones and heat affected zones in superalloy 713C

    Science.gov (United States)

    Lachowicz, M. B.; Dudziński, W.

    2012-09-01

    In this paper, metallographic examinations, characterising microstructural changes in the 713C superalloy subjected to remelting by GTA method, are presented. In the fusion zone, precipitation of M23C6 or M6C carbides based on chromium and molybdenum was observed. Eutectic mixtures of ( γ- gg')-M x C y type with highly developed morphology were also perceived. It was found that, in the matrix areas with non-homogeneous chemical composition, the eutectic reaction γ-γ' can occur at the temperature close to that of the precipitation of the M x C y carbides. The presence of silicon in the carbide phases can be conducive to lowering their solidification point by creating low-melting compound NbSi. Both in the fusion zone (FZ) and in the heat-affected zone (HAZ), the secondary precipitates of the Ni3(AlTi)- γ' phase, varying in size from 50 to 100 nm, were found. The lattice mismatch factor of the γ and γ' particles was +0.48 % to +0.71 %, which is characteristic of the coherent precipitates of the Ni3Al phase enriched with titanium. No dislocations or stacking faults were observed in the microstructure of the FZ. In the HAZ, some primary undissolved γ' precipitates, with a part of aluminium probably replaced with niobium were observed, which raised their melting point.

  14. Hydrological and Oceanographic Considerations for Integrated Coastal Zone Management in Southern Belize.

    Science.gov (United States)

    Heyman; Kjerfve

    1999-09-01

    / The objectives of this study are to: (1) characterize the meteorology and hydrology of the Maya Mountain-Marine Area Transect in southern Belize, (2) employ a simple water balance model to examine the discharge rates of seven watersheds to Port Honduras, (3) test the validity of the hydrological model, (4) explore the implications of potential landscape and hydrological alterations, and (5) examine the value of protected areas. The southern coastal portion of the study area is classified as wet tropical forest and the remainder as moist tropical forest. Rainfall is 3000-4000 mm annually. Resulting annual freshwater discharge directly into Port Honduras is calculated at 2.5 x 10(9) m3, a volume equal to the basin. During the rainy season, June-September, 84% of the annual discharge occurs, which causes the bay to become brackish. Port Honduras serves as an important nursery ground for many species of commercially important fish and shellfish. The removal of forest cover in the uplands, as a result of agriculture, aquaculture, and village development, is likely to significantly accelerate erosion. Increased erosion would reduce soil fertility in the uplands and negatively affect mangrove, seagrass, and coral reef productivity in the receiving coastal embayment. Alternatively, the conservation of an existing protected areas corridor, linking the Maya Mountains to the Caribbean Sea, is likely to enhance regional sustainable economic development. This study aims to support environmental management at the scale of the "ecoscape"-a sensible ecological unit of linked watersheds and coastal and marine environments.KEY WORDS: Ecosystem management; Coastal zone management; Belize; Hydrologyhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n2p229.html

  15. Variability of suspended particulate matter concentrations and organic compounds in frontal zones of the Atlantic and Southern oceans

    Science.gov (United States)

    Nemirovskaya, I. A.; Kravchishina, M. D.

    2016-01-01

    The concentrations of suspended particulate matter (SPM) and particulate forms of the organic compounds (hydrocarbons, lipids, and chlorophyll a) were determined in the surface water layers of the Atlantic and Southern oceans during February to May of 2012 and 2014. It was found that the distribution of concentrations of the studied components is mainly affected by the location of frontal zones. When ice cover forms in the Southern Ocean, the changes in water temperature and phytoplankton development at the ice-water interface result in an increase of the concentrations of SPM, chlorophyll a, and, to a lesser extent, of lipids and hydrocarbons in the surface water layer. The occasional sharp increase of hydrocarbon concentrations caused by anthropogenic pollution was registered at local parts of water areas in the east of the Atlantic Ocean, as well as in the North and Baltic seas.

  16. Southern Hemisphere Storm Zones on Mars: Implications of MOLA Topography

    Science.gov (United States)

    Hollingsworth, J. L.; Haberle, R. M.; Schaeffer, J.

    1999-01-01

    Using the NASA Ames Mars general circulation model and recent Mars orbiter laser altimeter (MOLA) global topography, annual-cycle simulations have been performed corresponding to a lowglobally-averaged atmospheric dust loading (tau= 0 - 3). Comparisons of key global circulation fields as simulated utilizing previous topography datasets and those using the new Mars global topography have been carried out. Values of globally and/or hemispheric averaged kinetic energy associated with the longitudinally averaged (i.e., zonal) circulation and longitudinal departures (i.e., eddy components) as a function of season for simulations using the different topography datasets are provided contributions arising frommeteorological variability associated with thermal tides, stationary circulation components and recurrent weather systems (transient baroclinc and/or barotropic eddies). It can be noted that eddy activity in the northern hemisphere (NH) is substantially diminished using the new topographic data, and that at some seasons, the southern hemisphere (SH) activity is moderately increased. Additional information is contained in the original extended abstract.

  17. Bimodal variation in mercury wet deposition to the coastal zone of the southern Baltic

    Directory of Open Access Journals (Sweden)

    P. Siudek

    2009-10-01

    Full Text Available In the following periods: November 2005–June 2006 and October 2007–January 2009, concentrations and deposition rates of total mercury (THg and Hg(II were measured in precipitation over the urbanized and industrialized area of the southern Baltic – the city of Gdynia. Rains over the coastal zone had different concentrations of total mercury, they ranged from 8.6 to 118.0 ng L−1, out of which about 32% were labile, inorganic forms, easily reducible in a SnCl2 solution. Over the southern Baltic two maxima of concentrations were observed: first, in the heating season and second, in the non-heating season. Elevated concentrations of mercury in precipitations during heating seasons were the result of the activity of local emission sources (intensive combustion of fossil fuels in domestic furnaces and individual power and heat generating plants. During the warm season, precipitation over the southern Baltic could clean the air from Hg reemitted from sea and land surfaces. Precipitations, which purified marine and continental air masses were responsible for the comparable input of mercury to the coastal zone. The wet deposition value in 2008 was estimated to be 28.9 μg m−2. In the coastal zone of the southern Baltic, acid precipitations with the elevated Hg concentrations are very frequent.

  18. Factors affecting the kinematic interpretation of asymmetric boudinage in shear zones

    Science.gov (United States)

    Goldstein, Arthur G.

    Based on work along a major mylonite zone in the northern Appalachians and scale model studies, a new mechanism for the origin of asymmetric boudins in shear zones is proposed. Along the Honey Hill Fault in southern Connecticut, granitic sills intruded into calc-silicate gneisses and schists were oblique to the boundaries of the mylonite zone and experienced the following sequence in the production of sigmoidal boudins: (1) as the calc-silicate schists experienced mylonitization and flow, the more competent, coarse-grained granitic sills deformed by extensional fracturing and quartz veining; (2) continued extension of granitic sills was accommodated by 'normal' shear on early-formed quartz veins; (3) continuing extension of sills and ductile modification of the corners of boudins resulted in granitic 'fish' with tails which stream from the top of the boudin in the 'down-dip' direction and from the bottom in the 'up-dip' direction. Based on a variety of kinematic indicators, the sense of asymmetry of the tails is identical to that expected for recrystallization tails on sheared augen (σ structure). Models composed of silicone putty and Plasticine were created to investigate the effect of pre-shearing geometry on boudin evolution, and were deformed in a simple shear device. The models reproduce the kinematics deduced from field relations and suggest that one of the primary factors in controlling the amount of extension is the angle which early veins make with the shear zone boundary. Varying the angular relationships in the models suggests that other pre-shearing geometric factors may affect the geometry of boudins formed in this way. Boudins formed through this mechanism appear very similar to Hanmer's type II asymmetric boudins. Because the pre-shearing geometry can exert a control on boudin asymmetry, caution should be used when attempting to deduce shear sense or shear strain values from asymmetric boudinage.

  19. Surface and subsurface structural analysis of a part of Washita Valley fault zone, southern Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Palladino, D.L.

    1984-04-01

    The Washita Valley fault zone is one of the major northwest-trending structures in southern Oklahoma. This fault system is believed to have originated as a series of normal faults during the formation of the southern Oklahoma aulacogen by late Precambrian or early Cambrian time and to have been reactivated during the Arbuckle orogeny in the Pennsylvanian. Descriptions of movement along the Washita Valley fault zone during Pennsylvanian deformation include numerous interpretations, the most common being left-lateral strike slip with 30-40 mi (50-65 km) of displacement. Structures in the area, however, suggest an alternate model. A detailed field study of small folds, faults, fracture arrays, slickensides, and drainage patterns was conducted along the southeastern half of the Washita Valley fault zone. An attempt has been made to relate these small-scale features to the major structures in the area to determine the orientation of the major compressive stress during deformation and the relative amounts of strike-slip vs. reverse dip-slip movement along the fault zone. Exploration for oil and gas along the Washita Valley fault zone has identified several overturned folds and repeated sections. Field observations in the study area include small drag folds and thrust faults parallel to the trend of the Washita Valley fault zone. The two major anticlines in the area, the Arbuckle and the Tishomingo, are both nearly parallel to the trend of the fault zone. These data suggest a model of deformation involving a large component of reverse dip-slip faulting with major duplication of strata.

  20. A 11,000 yr palaeotemperature reconstruction from the southern boreal zone in Finland

    Science.gov (United States)

    Heikkilä, Maija; Seppä, Heikki

    2003-03-01

    The ecotone between the boreo-nemoral (hemiboreal) and the southern boreal vegetation zones constitutes the northern distributional limit of a number of thermophilous tree species in northern Europe and is, to a large extent, controlled by climatic conditions. We present a quantitative annual mean temperature reconstruction from a high-resolution pollen stratigraphy in southern boreal Finland, using a pollen-climate calibration model with a cross-validated prediction error of 0.9°C. Our model reconstructs low but steadily rising annual mean temperature from 10,700 to 9000 cal yr BP. At 8000-4500 cal yr BP reconstructed annual mean temperature reaches a period of highest values (Holocene thermal maximum) with particularly high temperatures (2.0-1.5°C higher than at present) at 8000-5800 cal yr BP. From 4500 cal yr BP to the present-day, reconstructed annual mean temperature gradually decreases by ca 1.5°C. Comparison of present results with palaeotemperature records from the Greenland ice cores, notably with the NorthGRIP δ18O record, shows marked similarities, suggesting parallel large-scale Holocene temperature trends between the North Atlantic and North European regions. The verification of the occurrence, timing, and nature of the short-term temperature fluctuations during the Holocene in the southern boreal zone in Europe requires replicate, high-resolution climate reconstructions from the region.

  1. Tectonic hydrothermal gold mineralisation in the outboard zone of the Southern Alps, New Zealand

    International Nuclear Information System (INIS)

    Gold-bearing veins cut a belt of low-grade (pumpellyite-actinolite/greenschist facies) schist in the Ben Ohau Range to the east of the Main Divide, in the outboard zone of the Southern Alps continental collisional zone, New Zealand. The schist has been exposed along the currently active Ostler Fault system, which has had c. 5 km of reverse motion since the Pliocene. The veins consist of quartz, ankerite, calcite, chlorite, and pyrite, with minor chalcopyrite and galena. Hydrothermal chlorite contains about 490 ppm Zn, and the gold contains 3-5 wt% Ag. Hydrothermal alteration of host rock is minor apart from Sr enrichment (up to four times background). Fluid inclusions in quartz are aqueous with minor dissolved CO2 and salts (18O = +10 to +14; δ13C = -6 to -10 per thousand) are similar to data from economic metamorphogenic Au deposits of the nearby Otago Schist, but minor meteoric incursion may have occurred. Isotopic data are also similar to veins formed in the inboard zone of the Southern Alps orogen. The Ben Ohau veins demonstrate that gold can be concentrated in low-grade schists distant from the most active part of the hydrothermal system driven by continental collision. (author). 45 refs., 6 figs., 3 tabs

  2. Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes

    OpenAIRE

    Pritchard, M. E.; Norabuena, E. O.; Jillings, C.; Boroschek, R.; Comte, D.; Simons, M.; T. H. Dixon; Rosen, P. A.

    2007-01-01

    We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 M_w 7.7 and 23 June 2001 M_w 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations...

  3. Structural control of the Gagua "Wedge" Zone east of Taiwan Island on the southern Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Yanpeng; LIU; Baohua; WU; Jinlong; LIANG; Ruicai; L

    2005-01-01

    Based on compositive analysis and interpretation of the observed and historical data, the geophysical field characters and structural properties of the Gagua "Wedge" Zone of the sea area east of Taiwan Island and the primary tectonic stress direction and its variabilities of backarc spreading in the southern Okinawa Trough are studied. It is concluded from the study results that the Gagua "Wedge" Zone is structurally consistent with the Gagua ridge and two fault basins on both sides of the Gagua ridge, and adjusts the moving direction and distance of the western Philippine Sea plate to make the northwestward motion of the plate on its east side change to the northward subduction of the plate on its west side so that the primary tectonic stress direction of the Okinawa Trough changed from NW-SE to nearly N-S, which provided the stress source for the Okinawa Trough to enter the second spreading stage.

  4. Simulated effects of southern hemispheric wind changes on the Pacific oxygen minimum zone

    Science.gov (United States)

    Getzlaff, Julia; Dietze, Heiner; Oschlies, Andreas

    2016-01-01

    A coupled ocean biogeochemistry-circulation model is used to investigate the impact of observed past and anticipated future wind changes in the Southern Hemisphere on the oxygen minimum zone in the tropical Pacific. We consider the industrial period until the end of the 21st century and distinguish effects due to a strengthening of the westerlies from effects of a southward shift of the westerlies that is accompanied by a poleward expansion of the tropical trade winds. Our model results show that a strengthening of the westerlies counteracts part of the warming-induced decline in the global marine oxygen inventory. A poleward shift of the trade-westerlies boundary, however, triggers a significant decrease of oxygen in the tropical oxygen minimum zone. In a business-as-usual CO2 emission scenario, the poleward shift of the trade-westerlies boundary and warming-induced increase in stratification contribute equally to the expansion of suboxic waters in the tropical Pacific.

  5. Successful foraging zones of southern elephant seals from the Kerguelen Islands in relation to oceanographic conditions.

    Science.gov (United States)

    Bailleul, Frédéric; Charrassin, Jean-Benoît; Monestiez, Pascal; Roquet, Fabien; Biuw, Martin; Guinet, Christophe

    2007-11-29

    Southern elephant seals, Mirounga leonina, undertake large-scale oceanic movements to access favourable foraging areas. Successful foraging areas of elephant seals from the Kerguelen Islands are investigated here in relation to oceanographic parameters. Movements and diving activity of the seals as well as oceanographic data were collected through a new generation of satellite relayed devices measuring and transmitting locations, pressure, temperature and salinity. For the first time, we have associated foraging behaviour, determined by high increased sinuosity in tracks, and dive density (i.e. number of dives performed per kilometre covered), and changes in body condition, determined by variations in drift rate obtained from drift dives, to identify the oceanographic conditions of successful foraging zones for this species. Two main sectors, one close to the Antarctic continent and the other along the Polar Front (PF), where both foraging activity and body condition increase, seem to be of particular interest for the seals. Within these regions, some seals tended to focus their foraging activity on zones with particular temperature signatures. Along the Antarctic continent, some seals targeted colder waters on the sea bottom during benthic dives, while at the PF the favourable zones tended to be warmer. The possible negative effect of colder waters in Antarctic on the swimming performances of potential fish or squid prey could explain the behaviour of elephant seals in these zones, while warmer waters within the PF could correspond to the optimal conditions for potential myctophid prey of elephant seals. PMID:17472917

  6. Spatial modeling of coupled hydrologic-biogeochemical processes for the Southern Sierra Critical Zone Observatory

    Science.gov (United States)

    Tague, C.

    2007-12-01

    One of the primary roles of modeling in critical zone research studies is to provide a framework for integrating field measurements and theory and for generalizing results across space and time. In the Southern Sierra Critical Zone Observatory (SCZO), significant spatial heterogeneity associated with mountainous terrain combined with high inter-annual and seasonal variation in climate, necessitates the use of spatial-temporal models for generating landscape scale understanding and predictions. Science questions related to coupled hydrologic and biogeochemical fluxes within the critical zone require a framework that can account for multiple and interacting processes. One of the core tools for the SCZO will be RHESSYs (Regional hydro-ecologic simulation system). RHESSys is an existing GIS-based model of hydrology and biogeochemical cycling. For the SCZO, we use RHESSys as an open-source, objected oriented model that can be extended to incorporate findings from field-based monitoring and analysis. We use the model as a framework for data assimilation, spatial-temporal interpolation, prediction, and scenario and hypothesis generation. Here we demonstrate the use of RHESSys as a hypothesis generation tool. We show how initial RHESSys predictions can be used to estimate when and where connectivity within the critical zone will lead to significant spatial or temporal gradients in vegetation carbon and moisture fluxes. We use the model to explore the potential implications of heterogeneity in critical zone controls on hydrologic processes at two scales: micro and macro. At the micro scale, we examine the role of preferential flowpaths. At the macro scale we consider the importance of upland-riparian zone connectivity. We show how the model can be used to design efficient field experiments by, a-priori providing quantitative estimate of uncertainty and highlighting when and where measurements might most effectively reduce that uncertainty.

  7. Atlanta ariejansseni, a new species of shelled heteropod from the Southern Subtropical Convergence Zone (Gastropoda, Pterotracheoidea)

    Science.gov (United States)

    Wall-Palmer, Deborah; Burridge, Alice K.; Peijnenburg, Katja T.C.A.

    2016-01-01

    Abstract The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to ocean acidification and ocean warming, and atlantids are likely to be useful indicators of these changes. However, we still lack fundamental information on their taxonomy and biogeography, which is essential for monitoring the effects of a changing ocean. Integrated morphological and molecular approaches to taxonomy have been employed to improve the assessment of species boundaries, which give a more accurate picture of species distributions. Here a new species of atlantid heteropod is described based on shell morphology, DNA barcoding of the Cytochrome Oxidase I gene, and biogeography. All specimens of Atlanta ariejansseni sp. n. were collected from the Southern Subtropical Convergence Zone of the Atlantic and Indo-Pacific oceans suggesting that this species has a very narrow latitudinal distribution (37–48°S). Atlanta ariejansseni sp. n. was found to be relatively abundant (up to 2.3 specimens per 1000 m3 water) within this narrow latitudinal range, implying that this species has adapted to the specific conditions of the Southern Subtropical Convergence Zone and has a high tolerance to the varying ocean parameters in this region. PMID:27551204

  8. Biodiversity and spatial distribution of medusae in the Magellan Region (Southern Patagonian Zone

    Directory of Open Access Journals (Sweden)

    Sergio Palma

    2014-11-01

    Full Text Available Epipelagic medusae collected in the Magellan Region (Southern Patagonian Zone during spring 2009 were analyzed. A total of 27 species of medusae were identified (25 hydromedusae and 2 scyphomedusae. Twelve medusae species were recorded for the first time in the Magellan region. Six dominant species were found: Clytia simplex (19.8%, Rhopalonema funerarium (16.2%, Aurelia sp. (15.9%, Bougainvillia muscoides (15.5%, Proboscidactyla stellata (8.9%, and Obelia spp. (6.0%. The horizontal distribution of all these species, except Obelia spp., showed the highest abundances to the south of 54°S, particularly in the Almirantazgo and Agostini fjords and in the Beagle Channel. Most of the dominant species were collected in shallow strata (0-50 m, with less saline waters (<30, except for R. funerarium, which was mainly collected above depths deeper than 25 m in more saline waters (30-33. These results confirm the success of several species in the colonization of the inland waters of the Southern Patagonian Zone.

  9. Influence of the welding parameters on the heat affected zone for aluminium welding

    Directory of Open Access Journals (Sweden)

    Meseguer-Valdenebro José L.

    2016-01-01

    Full Text Available This work analyzes the Heat Affected Zone in an aluminum alloy welded assembly using the Metal Inert Gas welding technique. Making use of numerical simulations of the involved thermal processes, the aluminum alloy cooling curve is calculated and the extension of the Heat Affected Zone is evaluated. The connection between this last parameter, the cooling rate, and the maximum obtained temperature is assessed. Additionally, the response surface method is exploited to fit the dependence of the Heat Affected Zone with the welding parameters and to optimize these parameters in order to minimize that region.

  10. Seismicity and structure of Nazca Plate subduction zone in southern Peru

    Science.gov (United States)

    Lim, H.; Kim, Y.; Clayton, R. W.

    2015-12-01

    We image the Nazca plate subduction zone system by detecting and (re)locating intra-slab earthquakes in southern Peru. Dense seismic arrays (PeruSE, 2013) were deployed along four lines to target geophysical characterization of the subduction system in the transition zone between flat and normal dipping segments of the Nazca plate (2-15°S). The arc volcanism is absent near the flat slab segment, and currently, the correlation between the location of the active volcanic front and corresponding slab depth is neither clear nor consistent between previously published models from seismicity. We detect 620 local earthquakes from August 2008 to February 2013 by manually picking 6559 and 4145 arrival times for P- and S-phases, respectively. We observe that the S-phase data is helpful to reduce the trade-off between origin time and depth of deeper earthquakes (>100 km). Earthquake locations are relocated to constrain the Nazca slab-mantle interface in the slab-dip transition zone using 7322 measurements of differential times of nearby earthquake pairs by waveform cross-correlation. We also employ the double-difference tomography (Zhang and Thurber, 2003) to further improve earthquake source locations and the spatial resolution of the velocity structure simultaneously. The relocated hypocenters clearly delineate the dipping Wadati-Benioff zone in the slab-dip transition zone between the shallow- (25°) to-flat dipping slab segment in the north and the normal (40°) dipping segment in the south. The intermediate-depth seismicity in the flat slab region stops at a depth of ~100 km and a horizontal distance of ~400 km from the trench. We find a significant slab-dip difference (up to 10°) between our relocated seismicity and previously published slab models along the profile region sampling the normal-dip slab at depth (>100 km).

  11. Deep critical zone weathering at the southern Sierra Nevada Critical Zone Observatory imaged by seismic waveform tomography

    Science.gov (United States)

    Hayes, J. L.; Holbrook, W.; Riebe, C. S.

    2012-12-01

    We present seismic velocity profiles that constrain the extent of weathering and frequency of velocity heterogeneities at depths less than 40 m in the southern Sierra Nevada Critical Zone Observatory (SSCZO) from waveform tomography modeling of a seismic refraction experiment. Near-surface variations in seismic velocity reflect differences in alteration of parent material by chemical, hydrological and biological processes. Previous traveltime tomography models from these data suggest that the depth to bedrock in the SSCZO is typically ~25 m; thus the potential for subsurface water storage in regolith may be a larger component of water storage than previously thought. Traveltime tomography is unable to resolve heterogeneities with horizontal wavelengths less than 10 m, such as those observed along a surveyed road cut beneath our seismic profile. For a higher resolution seismic image, we apply waveform tomography, which is more robust than traveltime tomography at approximating the wave equation and thus should provide images of subsurface heterogeneities such as corestones and fracture networks. This technique uses a weak scattering approximation to account for the amplitude and phase of the recorded waveforms, rather than just the traveltimes. A 48-channel vertical geophone array and hammer source was deployed over a 7 m high road cut with receiver and shot spacing of 2 m and 4 m respectively. The road cut displays lateral variation in weathering from a friable saprolite to coherent granodiorite which are compared to velocity variations modeled using waveform tomography.

  12. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    CERN Document Server

    Rivera, Jose Luis; Guerra-Gonzalez, Roberto

    2015-01-01

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect ...

  13. Eurasian Otters in Micro Dams of Southern Bulgaria: Where to Place the Monitoring Zones?

    Directory of Open Access Journals (Sweden)

    Dilian Georgiev

    2009-04-01

    Full Text Available Ten micro dam sites were studied in Southern Bulgaria between 2005 and 2007. They were situated below 700 metres above sea level in the Upper Thracian Valley and the Sredna Gora mountain. All the bank perimeters, totaling 24.72 kilometres, were walked searching for otter spraint sites. Most of them were found in the area around the river inflow (n=53, 40.5% followed by those near the wall of the dam (n=39, 29.8%. The other spraint sites were found in the two other zones of equal length in the middle part of the basins. The average levels of preference index showed the highest levels in the river inlet and dam wall zones. They were highest at the river inflow end, 1.6 (min-max=0.7–4.0 and a little lower near the wall, 1.2 (min-max=0.0–3.0. The middle zones of the basin were not so preferentially selected as spraint sites by otters, having index values about three times lower. We recommend otter monitoring at such basins to be focused on the areas close to the main river filling them.

  14. Analysis of the heat affected zone in CO2 laser cutting of stainless steel

    Directory of Open Access Journals (Sweden)

    Madić Miloš J.

    2012-01-01

    Full Text Available This paper presents an investigation into the effect of the laser cutting parameters on the heat affected zone in CO2 laser cutting of AISI 304 stainless steel. The mathematical model for the heat affected zone was expressed as a function of the laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position using the artificial neural network. To obtain experimental database for the artificial neural network training, laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of the cutting parameter. Using the 27 experimental data sets, the artificial neural network was trained with gradient descent with momentum algorithm and the average absolute percentage error was 2.33%. The testing accuracy was then verified with 6 extra experimental data sets and the average predicting error was 6.46%. Statistically assessed as adequate, the artificial neural network model was then used to investigate the effect of the laser cutting parameters on the heat affected zone. To analyze the main and interaction effect of the laser cutting parameters on the heat affected zone, 2-D and 3-D plots were generated. The analysis revealed that the cutting speed had maximum influence on the heat affected zone followed by the laser power, focus position and assist gas pressure. Finally, using the Monte Carlo method the optimal laser cutting parameter values that minimize the heat affected zone were identified.

  15. Geologic character of tuffs in the unsaturated zone at Yucca Mountain, southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Scott, R.B.; Spengler, R.W.; Diehl, S.; Lappin, A.R.; Chornack, M.P.

    1982-12-31

    At Yucca Mountain, a potential site for a high-level nuclear waste repository on the Nevada Test Site in southern Nevada, evaluation of the geologic setting and rock physical properties, along with previous regional hydrologic studies, has provided background that can be used for construction of a preliminary conceptual hydrologic model of the unsaturated zone. The 500-m-thick unsaturated portion of Yucca Mountain consists of alternating layers of two contrasting types of tuff. One type consists of highly fractured, densely welded, relatively nonporous but highly transmissive ash-flow tuffs. The other type consists of relatively unfractured, nonwelded, highly porous but relatively nontransmissive, argillic and zeolitic bedded tuffs and ash-flow tuffs. The contrast between these two sets of distinctive physical properties results in a stratified sequence best described as "physical-property stratigraphy" as opposed to traditional petrologic stratigraphy of volcanic rocks. The vast majority of recharge through the unsaturated zone is assumed to be vertical; the dominant migration may occur in fractures of densely welded tuffs and in the matrix of nonwelded tuff, but the mode of fluid flow in these unsaturated systems is undetermined. Limited lateral flow of recharge may occur at horizons where local perched water tables may exist above relatively nontransmissive zeolitized nonwelded tuffs. The pervasive north-northwest-striking fractures may control the direction of lateral flow of recharge, if any, in the unsaturated zone, and certainly that direction coincides closely with the observed southeasterly flow direction in the saturated zone under Yucca Mountain. Empirical evaluation of this conceptual hydrologic model has begun. 41 refs., 18 figs., 2 tabs.

  16. Geologic character of tuffs in the unsaturated zone at Yucca Mountain, southern Nevada

    International Nuclear Information System (INIS)

    At Yucca Mountain, a potential site for a high-level nuclear waste repository on the Nevada Test Site in southern Nevada, evaluation of the geologic setting and rock physical properties, along with previous regional hydrologic studies, has provided background that can be used for construction of a preliminary conceptual hydrologic model of the unsaturated zone. The 500-m-thick unsaturated portion of Yucca Mountain consists of alternating layers of two contrasting types of tuff. One type consists of highly fractured, densely welded, relatively nonporous but highly transmissive ash-flow tuffs. The other type consists of relatively unfractured, nonwelded, highly porous but relatively nontransmissive, argillic and zeolitic bedded tuffs and ash-flow tuffs. The contrast between these two sets of distinctive physical properties results in a stratified sequence best described as ''physical-property stratigraphy'' as opposed to traditional petrologic stratigraphy of volcanic rocks. The vast majority of recharge through the unsaturated zone is assumed to be vertical; the dominant migration may occur in fractures of densely welded tuffs and in the matrix of nonwelded tuff, but the mode of fluid flow in these unsaturated systems is undetermined. Limited lateral flow of recharge may occur at horizons where local perched water tables may exist above relatively nontransmissive zeolitized nonwelded tuffs. The pervasive north-northwest-striking fractures may control the direction of lateral flow of recharge, if any, in the unsaturated zone, and certainly that direction coincides closely with the observed southeasterly flow direction in the saturated zone under Yucca Mountain. Empirical evaluation of this conceptual hydrologic model has begun. 41 refs., 18 figs., 2 tabs

  17. Results of trench perpendicular wide angle seismic transects across the Manila subduction zone offshore southern Taiwan

    Science.gov (United States)

    Eakin, D. H.; McIntosh, K. D.; Van Avendonk, H. J.

    2011-12-01

    Multi-channel seismic reflection and wide-angle seismic data collected in 2009 aboard the R/V Marcus Langseth as part of the TAIGER program delineate the crustal structure of the Manila subduction zone in the northern South China Sea. As part of that project, we recorded marine seismic data using a deployment of ocean-bottom-seismometers (OBS) from the U.S. instrument pool and National Taiwan Ocean University. The region between northern Luzon and southern Taiwan evolves from oceanic subduction to incipient arc-continent collision. This presentation focuses on results of 2 offshore transects across the Manila subduction zone offshore southern Taiwan. Our goal here is to document the transition from pure oceanic subuction in the south to incipient arc-continent collision in the north, an understanding of which is integral for future geodynamic modeling of the advanced arc-continent collision in the north. The northern transect, line T2 is located at 21.4° N and used 30 OBSs. Line T1 was located at 20.5° N and used 27 OBSs across the Manila subduction zone. Data quality is extremely variable due to the local geology and quality of seafloor coupling at each instrument. Preliminary travel-time tomography of transect T2 shows a 10-15 km thick Eurasian crust with crustal velocities of 5-7.5 km/sec entering the Manila trench suggesting thinned continental crust, serpentinized upper mantle, or both in this region. The model shows the accretionary prism to be cored by high velocity material (6-7 km/sec) that may be the result of accretion of crustal material from the subducting Eurasian slab. We also observe asymmetric crustal thickening beneath the Gagua Ridge that is potentially a result of failed subduction of the Philippine Sea Plate westward along the Gagua Ridge. The wide-angle data is complimented by MCS reflection data to constrain sediment thickness, top of the crystalline basement, and moho. Preliminary work is in progress with transect T1 which will be

  18. Spatial and temporal patterns of nonvolcanic tremor along the southern Cascadia subduction zone

    Science.gov (United States)

    Boyarko, Devin C.; Brudzinski, Michael R.

    2010-08-01

    Episodic tremor and slip (ETS), the spatial and temporal correlation of slow slip events monitored via GPS surface displacements and nonvolcanic tremor (NVT) monitored via seismic signals, is a newly discovered mode of deformation thought to be occurring downdip from the seismogenic zone along several subduction zone megathrusts. To provide overall constraints on the distribution and migration behavior of NVT in southern Cascadia, we apply a semiautomated location algorithm to seismic data available during the EarthScope Transportable Array deployment to detect the most prominent pulses of NVT and invert analyst-refined relative arrival times for source locations. In the processing, we also detect distinct and isolated bursts of energy within the tremor similar to observations of low-frequency earthquakes in southwest Japan. We investigate in detail eight NVT episodes between November 2005 and August 2007 with source locations extending over a 650 km along-strike region from northern California to northern Oregon. We find complex tremor migration patterns with periods of steady migration (4-10 km/d), halting, and frequent along-strike jumps (30-400 km) in activity. The initiation and termination points of laterally continuous tremor activity appear to be repeatable features between NVT episodes which support the hypothesis of segmentation within the ETS zone. The overall distribution of NVT epicenters occur within a narrow band primarily confined by the surface projections of the 30 and 40 km contours of the subducting plate interface. We find as much as 50 km spatial offset from the updip edge of the tremor source zone to the downdip edge of the thermally and geodetically defined transition zone, which may inhibit ETS from triggering earthquakes further updip. Intriguingly, NVT activity is spatially anticorrelated with local seismicity, suggesting the two processes are mutually exclusive. We propose that the transition in frictional behavior coupled with high pore

  19. Microstructure and Hardness of T250 Maraging Steel in Heat Affected Zone

    Institute of Scientific and Technical Information of China (English)

    MO De-feng; HU Zheng-fei; CHEN Shu-juan; WANG Chun-xu; HE Guo-qiu

    2009-01-01

    Electron-beam (EB) welding was used in T250 maraging steel,microstructures of both base material and heat affected zone (HAZ) were investigated by optical microscopy (OM),scanning electron microscopy (SEM) and transmission electron microscopy (TEM),and microhardness was tested.The results showed that during EB welding,the HAZ of T250 maraging steel exhibited a continuous gradient structure.The microstructure of the entire HAZ,from fusion line,could be divided into four zones:fusion zone,overheated zone,transition zone,and hardened zone.The microhardness showed a distinct regularity in each area.The softest region was the fusion zone,whereas the hardest was the hardened zone.In the overheated zone,the hardness increased as the grain size decreased.Furthermore,in the transition zone,the hardness level dropped noticeably.The peak temperature during the thermal cycle had a great influence on the formation of reverted austenite and dissolution of the precipitated particles,which contributed a lot to the microstrueture and hardness of this material.

  20. The Eastern California Shear Zone as the northward extension of the southern San Andreas Fault

    Science.gov (United States)

    Thatcher, Wayne R.; Savage, James C.; Simpson, Robert W.

    2016-01-01

    Cluster analysis offers an agnostic way to organize and explore features of the current GPS velocity field without reference to geologic information or physical models using information only contained in the velocity field itself. We have used cluster analysis of the Southern California Global Positioning System (GPS) velocity field to determine the partitioning of Pacific-North America relative motion onto major regional faults. Our results indicate the large-scale kinematics of the region is best described with two boundaries of high velocity gradient, one centered on the Coachella section of the San Andreas Fault and the Eastern California Shear Zone and the other defined by the San Jacinto Fault south of Cajon Pass and the San Andreas Fault farther north. The ~120 km long strand of the San Andreas between Cajon Pass and Coachella Valley (often termed the San Bernardino and San Gorgonio sections) is thus currently of secondary importance and carries lesser amounts of slip over most or all of its length. We show these first order results are present in maps of the smoothed GPS velocity field itself. They are also generally consistent with currently available, loosely bounded geologic and geodetic fault slip rate estimates that alone do not provide useful constraints on the large-scale partitioning we show here. Our analysis does not preclude the existence of smaller blocks and more block boundaries in Southern California. However, attempts to identify smaller blocks along and adjacent to the San Gorgonio section were not successful.

  1. Seismological and Geodynamic Monitoring Network in the "javakheti" Test Zone in the Southern Caucasus

    Science.gov (United States)

    Arakelyan, A.; Babayan, H.; Karakhanyan, A.; Durgaryan, R.; Basilaia, G.; Sokhadze, G.; Bidzinashvili, G.

    2012-12-01

    The Javakheti Highland located in the border region between Armenia and Georgia (sharing a border with Turkey) is an area in the Southern Caucasus of young Holocene-Quaternary volcanism and a region with convergence of a number of active faults. Issues related to the geometry, kinematics and slip-rate of these faults and assessment of their seismic hazard remain unclear in part due to the fragmentary nature of the studies carried out soley within the borders of each of the countries as opposed to region wide. In the frame of the ISTC A-1418 Project "Open network of scientific Centers for mitigation risk of natural hazards in the Southern Caucasus and Central Asia" the Javakheti Highland was selected as a trans-border test-zone. This designation allowed for the expansion and upgrading of the seismological and geodynamic monitoring networks under the auspices of several international projects (ISTC CSP-053 Project "Development of Communication System for seismic hazard situations in the Southern Caucasus and Central Asia", NATO SfP- 983284 Project "Caucasus Seismic Emergency Response") as well as through joint research programs with the National Taiwan University and Institute of Earth Sciences (IES, Taiwan), Universite Montpellier II (France) and Ecole et Observatoire des Sciences de la Terre-Université de Strasbourg (France). Studies of geodynamic processes, and seismicity of the region and their interaction have been carried out utilizing the newly established seismological and geodynamic monitoring networks and have served as a basis for the study of the geologic and tectonic structure . Upgrading and expansion of seismological and geodynamic networks required urgent solutions to the following tasks: Introduction of efficient online systems for information acquisition, accumulation and transmission (including sattelite systems) from permanent and temporary installed stations, Adoption of international standards for organization and management of databases in GIS

  2. Literacy in the Southern Sudan: A Case Study of Variables Affecting Literacy Programs.

    Science.gov (United States)

    Cowan, J. Ronayne

    1983-01-01

    Describes the Local Languages Literacy Project in the Southern Sudan; delineates the most important educational, socioeconomic, and linguistic variables affecting the success of large-scale literacy programs in Africa; and questions the widely held assumption that indigenous language literacy is essential to subsequent literacy in the prestige…

  3. Profitability of yam production in Southern Guinea Savanna zone of Nigeria

    Directory of Open Access Journals (Sweden)

    Asala S. W.

    2016-03-01

    Full Text Available Yam production is a component of farming activities by most farmers in the Southern Guinea Savannah zone of Nigeria. However, many farmers do not seem to find farming a financially rewarding exercise. This study therefore aimed to find out the profit margin of yam production by farmers in this zone. A survey of farmers’ fields was carried out in 2013 in five major yam producing areas in Nigeria, namely; Benue, Kogi, Kwara, Niger Nassarawa States and Abuja Federal Capital Territory. Fifty four (54 respondents were recruited into the study sample using structured questionnaire and interview method. The farmers cultivated mainly Dioscorea rotundata Poir (white or guinea yam for commercial purposes while D. alata L. (water yam, D. cayenensis Lam (yellow yam, D. dumetorum Kunth (bitter yam and D. bulbifera L. (aerial yam are intercropped with D. rotundata for home consumption only. Yam production includes cultural operations such as heap preparation, staking and weed control. Some of the major constraints identified by the farmers were high cost of input such as planting materials (yam seed or setts, unreliable source of credit and unpredictable weather conditions. Net income benefit analysis revealed a positive return per hectare of land under yam production. The production of yam on one hectare of farm field will translate to a net profit of ₦450,000.00 equivalent to US $2,000.00. It was recommended that yam production could be a financially profitable endeavor if cost-reducing steps are engaged.

  4. Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes

    Science.gov (United States)

    Pritchard, M. E.; Norabuena, E. O.; Ji, C.; Boroschek, R.; Comte, D.; Simons, M.; Dixon, T. H.; Rosen, P. A.

    2007-03-01

    We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 Mw 7.7 and 23 June 2001 Mw 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations. Our two-dimensional slip models derived from only teleseismic body waves from South American subduction zone earthquakes with Mw > 7.5 do not reliably predict available geodetic data. In particular, we find significant differences in the distribution of slip for the 2001 earthquake from models that use only seismic (teleseismic and two strong motion stations) or geodetic (InSAR and GPS) data. The differences might be related to postseismic deformation or, more likely, the different sensitivities of the teleseismic and geodetic data to coseismic rupture properties. The earthquakes studied here follow the pattern of earthquake directivity along the coast of western South America, north of 5°S, earthquakes rupture to the north; south of about 12°S, directivity is southerly; and in between, earthquakes are bilateral. The predicted deformation at the Arequipa GPS station from the seismic-only slip model for the 7 July 2001 aftershock is not consistent with significant preseismic motion.

  5. Seismotectonic Study on the West Part of the Interaction Zone Between Southern Tianshan and Northern Tarim

    Institute of Scientific and Technical Information of China (English)

    Tian Qinjian; Ding Guoyu; Hao Ping

    2007-01-01

    The interaction zone between southern Tianshan and northern Tarim is located at the northeast side of Pamir.It is a region with high seismicity.We constructed a seismotectonic model for the west part of this zone from geological profiles,deep crust seismic detection and earthquake focal mechanisms data.Based on the synthesized geological features,deep crust structure,and earthquake focal mechanisins,we think that the main regional tectonic feature is that the Tianshan recto-lithostratigraphic unit overthrusts on the Tarim block.The Tianshan tectonic system includes the Maidan fault and thrust sheets in front of the fault;The Tarim tectonic system includes the underground northern Tarim margin fault,conjugate faults in basement and overthrust fault in shallow.The northern Tarim margin fault is a high angle fault deep in the Tarim crust, adjusting difierent trending deformation between Tianshan and Tarim.It is a major active fault that can generate large earthquakes.The other faults,such as the Tianshan overthrnst system and the Tarim basement faults in this area may generate moderately strong earthquakes with different styles.

  6. Impact of the invasive species Elaeagnus Angustifolia L. on vegetation in Pontic desert steppe zone (Southern Ukraine)

    NARCIS (Netherlands)

    Sudnik-Wojcikowska, B.; Moysiyenko, I.; Slim, P.A.; Moraczewski, I.R.

    2009-01-01

    The Irano-Turanian species – Russian olive (Elaeagnus angustifolia L.) – is one of most commonly planted tree in the shelterbelts in southern Ukraine. The consequences of introduction of the species from windbreaks, into areas of different land use in west and central Pontic desert steppe zone are e

  7. Shifts in Köppen-Geiger climate zones over southern Africa in relation to key global temperature goals

    Science.gov (United States)

    Engelbrecht, Christien J.; Engelbrecht, Francois A.

    2016-01-01

    Potential changes in Köppen-Geiger climate zones over southern Africa (Africa south of 22 °S) under future climate change are investigated using an ensemble of high-resolution projections of a regional climate model. The projections are performed under the A2 scenario of the Special Report on Emission Scenarios (SRES), and changes are presented for those times in the future when the increase in global average surface temperature reaches thresholds of 1, 2, and 3 °C, relative to the present-day baseline climatology. Widespread shifts in climate regimes are projected, of which the southern and eastern expansion of the hot desert and hot steppe zones is the most prominent. From occupying 33.1 and 19.4 % of southern Africa under present-day climate, these regions are projected to occupy between 47.3 and 59.7 % (hot desert zone) and 24.9 and 29.9 % (hot steppe zone) of the region in a future world where the global temperature has increased by 3 °C. The cold desert and cold steppe zones are projected to decrease correspondingly. The temperate regions of eastern South Africa, the Cape south coast, and winter rainfall region of the southwestern Cape are also projected to contract. An expansion of the hot steppe zone into the cold steppe and temperate zones may favor the intrusion of trees (and therefore the savanna biome) into the most pristine grasslands of southern Africa. However, the correlative climate-vegetation approach of using projected changes in Köppen-Geiger zones to infer future vegetation patterns is of limited value in the savanna complex of southern Africa, where complex feedbacks occur between carbon dioxide (CO2) concentrations, trees, C4 grasses, fire, and climate. The present-day temperate Cape Fynbos regime may come under increasing pressure as the encompassing temperate zone is invaded mainly from the east by the hot steppe climate regime under climate change, with the incidence of Fynbos fires also becoming more likely in a generally warmer and

  8. Seasonally chemical hydrology and ecological responses in frontal zone of the central southern Yellow Sea

    Science.gov (United States)

    Wei, Qin-Sheng; Li, Xian-Sen; Wang, Bao-Dong; Fu, Ming-Zhu; Ge, Ren-Feng; Yu, Zhi-Gang

    2016-06-01

    Based on annual-cycle survey data collected in 2006-2007 in the southern Yellow Sea (SYS) and analyses on the seasonally chemical hydrologic characteristics of the boundary front of the Yellow Sea Cold Water Mass (YSCWM) and Yellow Sea Warm Current (YSWC), the seasonal variations in upwelling along the frontal zone were determined, and the ecological impacts of the front were investigated. During the generation and dissipation of the YSCWM, the implied upwelling along its western front exhibited seasonal variation. The upwelling first shifted westward from the deep-water region to its westernmost point in summer then returned eastward. The intensity of the upwelling gradually increased from spring to summer and decreased in autumn. In spring, the existence of cold water west of the YSWC was not conducive to the reproduction of phytoplankton. Additionally, the front to the east of this cold water mass also made the western boundary of the phytoplankton bloom region in the central SYS more obvious, forming a prominent chlorophyll a (Chl-a) front. During the entire stratified season (summer and autumn), the upwelling in the frontal zone of the YSCWM played an essential role in maintaining the relatively high concentrations of Chl-a. In winter, the front that formed at the intersection of the YSWC and coastal cold water was also favorable for the formation of the high-Chl-a region. The distribution of anchovy biomass was closely related to the seasonal variations in the position of the frontal zone. In winter and spring, the tongue-shaped warm water and front associated with the intrusion of the YSWC into the SYS had a significant impact on anchovy. During the stratified season in summer and autumn, the development of a front near the boundary of the YSCWM was an important physical driving mechanism for the dense distribution of anchovy. This work enhanced the study of the seasonal relationships between the physical, chemical and biological processes in the frontal

  9. Thermochronology and tectonics of the Leeward Antilles: Evolution of the southern Caribbean Plate boundary zone

    Science.gov (United States)

    van der Lelij, Roelant; Spikings, Richard A.; Kerr, Andrew C.; Kounov, Alexandre; Cosca, Michael; Chew, David; Villagomez, Diego

    2010-01-01

    Tectonic reconstructions of the Caribbean Plate are severely hampered by a paucity of geochronologic and exhumation constraints from anastomosed basement blocks along its southern margin. New U/Pb, 40Ar/39Ar, apatite fission track, and apatite (U-Th)/He data constrain quantitative thermal and exhumation histories, which have been used to propose a model for the tectonic evolution of the emergent parts of the Bonaire Block and the southern Caribbean Plate boundary zone. An east facing arc system intruded through an oceanic plateau during ~90 to ~87 Ma and crops out on Aruba. Subsequent structural displacements resulted in >80°C of cooling on Aruba during 70–60 Ma. In contrast, exhumation of the island arc sequence exposed on Bonaire occurred at 85–80 Ma and 55–45 Ma. Santonian exhumation on Bonaire occurred immediately subsequent to burial metamorphism and may have been driven by the collision of a west facing island arc with the Caribbean Plate. Island arc rocks intruded oceanic plateau rocks on Gran Roque at ~65 Ma and exhumed rapidly at 55–45 Ma. We attribute Maastrichtian-Danian exhumation on Aruba and early Eocene exhumation on Bonaire and Gran Roque to sequential diachronous accretion of their basement units to the South American Plate. Widespread unconformities indicate late Eocene subaerial exposure. Late Oligocene–early Miocene dextral transtension within the Bonaire Block drove subsidence and burial of crystalline basement rocks of the Leeward Antilles to ≤1 km. Late Miocene–recent transpression caused inversion and ≤1 km of exhumation, possibly as a result of the northward escape of the Maracaibo Block.

  10. Diel cycles of hydrogen peroxide in marine bathing waters in Southern California, USA: In situ surf zone measurements

    International Nuclear Information System (INIS)

    Hydrogen peroxide is photochemically produced in natural waters. It has been implicated in the oxidative-induced mortality of fecal indicator bacteria (FIB), a microbial water quality measure. To assess levels and cycling of peroxide in beach waters monitored for FIB, diel studies were carried out in surf zone waters in July 2009 at Crystal Cove State Beach, Southern California, USA. Maximum concentrations of 160-200 nM were obtained within 1 h of solar noon. Levels dropped at night to 20-40 nM, consistent with photochemical production from sunlight. Day-time production and night-time dark loss rates averaged 16 ± 3 nM h-1 and 12 ± 4 nM h-1 respectively. Apparent quantum yields averaged 0.07 ± 0.02. Production was largely dominated by sunlight, with some dependence on chromophoric dissolved organic matter (CDOM) levels in waters with high absorption coefficients. Peroxide levels measured here are sufficient to cause oxidative-stress-induced mortality of bacteria, affect FIB diel cycling and impact microbial water quality in marine bathing waters.

  11. Qualitative and semiquantitative interpretation of aeromagnetic data over the Lancinha Shear Zone, Southern Ribeira Belt, in Paraná State, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Luís Gustavo de Castro

    2014-12-01

    Full Text Available The characterization of shear zones at the southern portion of the Ribeira Belt, PR, BR, as well as its recognition in depth is a major challenge. Despite the lack of subsurface information, the influence of such structures on the installation and evolution of the Paraná Basin during the Phanerozoic is widely accepted. Therefore, in this paper, are applied methods of anomaly enhancement (qualitative analysis and estimative of the sources depth (semiquantitative analysis, on the aeromagnetic coverage of the Lancinha Shear Zone area (LSZ in the Paraná state, in order to verify its spatial arrangement in subsurface. The processing resulted in the interpretation of magnetic-structural framework of the study area, which was validated by the depth estimative of the magnetic sources (Euler solutions. The results indicated the extension of the Lancinha, Morro Agudo and Itapirapuã shear zones under the Paraná Basin coverage.

  12. The Suruli shear zone and regional scale folding pattern in Madurai block of Southern Granulite Terrain, south India

    Indian Academy of Sciences (India)

    V Srinivasan; P Rajeshdurai

    2010-04-01

    Through the application of remote sensing techniques followed by field checks, the exact extension and nature of Suruli shear zone in Madurai block of southern granulite terrain (SGT) in south India is brought out for the first time in this work. The dominant rock type exposed in this area is charnockite intruded by granites. The Suruli ductile shear zone extends from just west of Kadaiyanallur in the south to Ganguvarpatti in the north over a length of 150 km. Between Kadaiyanallur and Kambam, the shear zone extends roughly in N–S direction. From Kambam, it swerves towards NE and then towards ENE near Ganguvarpatti. The strongly developed transposed foliation and mylonite foliation within the shear zone dip towards east only and so the eastern block (Varushanad hills) is the hanging wall and the western block (Cardamom hills) is the footwall of the shear zone. In the eastern block, three distinct phases of regional scale folding (F1, F2 and F3) are recognized. In complete contrast, the western block recorded only the last phase (F3) regional scale folding. As the more deformed eastern block (older terrain) moved over the relatively less deformed western block (younger terrain) along the Suruli shear zone, it is proposed that this shear zone is a thrust or reverse fault, probably of Proterozoic age. As there are evidences for decreasing displacement from north to south (i.e., from Ganguvarpatti to Kadaiyanallur), the Suruli shear zone could be a rotational thrust or reverse fault with the pivot located close to Kadaiyanallur. As the pivot is located near Achankovil shear zone which trends WNW-ESE (dip towards SSW), the Suruli shear zone could be splaying (branching) out from Achankovil shear zone. In a nutshell, the Suruli shear zone could be a splay, rotational thrust or reverse fault.

  13. Water extraction variability in the banana root zone affects the reliability of water balance

    Directory of Open Access Journals (Sweden)

    Alisson Jadavi Pereira da Silva

    2015-02-01

    Full Text Available Spatial and temporal variability of soil water extraction from the root zone affect soil water balance determination. The number of sensors installed in the root zone in studies addressing water balance is still set arbitrarily. This study provided an investigation of the water extraction process by banana (Musa spp. roots by (i determining the variability of water extraction from the banana tree root zone, (ii detecting differences in the estimation of evapotranspiration (ET by the soil water balance method when the number of soil profiles monitored in the roots zone varies, (iii and; determining the minimum number of Time Domain Reflectometry (TDR probes needed to obtain ET precision and accuracy similar to that determined by a drainage lysimeter. The field experiment was conducted in Cruz das Almas, in the state of Bahia, Brazil, where a drainage lysimeter was installed on a banana plantation. The water extraction in the banana root zone was quantified by the water content variations monitored in 72 points by TDRs, with measurements at 15-min intervals. The variability of water extraction in the banana root zone was medium to high. The range of variability affects the reliability of the crop evapotranspiration calculation by the soil water balance method. To prevent an overestimation of banana evapotranspiration, the water extraction in the soil profile must be monitored with at least 16 TDR probes installed at a minimum distance of 0.9 m and a minimum depth of 0.7 m.

  14. Microstructure of the heat-affected zone in 17-4 PH stainless steel

    International Nuclear Information System (INIS)

    The microstructure of the heat-affected zone (HAZ) in bead-on-plate welded 17-4 PH stainless steel was studied with special reference to the roles of prior heat treatment and heat input during welding. The HAZ in solution-annealed condition consists of three different microstructural zones containing: (I) retransformed martensite and reformed austenite; (II) over-aged martensite; and (III) under-aged martensite. In aged condition the HAZ consists of zones (I) and (II), while in over-aged condition it consists almost entirely of zone (II). The HAZ in solution-annealed and aged conditions is characterised by steep gradients in hardness, while in over-aged condition it has uniform hardness throughout. A good correlation was obtained between the calculated temperature distribution in the HAZ and the observed microstructural features. (orig.)

  15. Properties of the heat affected zone of a Nb microalloyed steel

    International Nuclear Information System (INIS)

    The weld thermal cycles and stress relieve heat treatment influences on multipass welds, by shielded metal arc welding process (SMAW), were evaluated in the heat affected zone of a Nb microalloyed steel, through Charpy-V notch tests, hardness measurements and microstructural aspects. (Author)

  16. Mechanical Properties and Microstructural Evolution of Simulated Heat-Affected Zones in Wrought Eglin Steel

    Science.gov (United States)

    Leister, Brett M.; DuPont, John N.; Watanabe, Masashi; Abrahams, Rachel A.

    2015-12-01

    A comprehensive study was performed to correlate the mechanical properties and microstructural evolution in the heat-affected zone of Eglin steel. A Gleeble 3500 thermo-mechanical simulator was used to simulate weld thermal cycles with different peak temperatures at a heat input of 1500 J/mm. These samples underwent mechanical testing to determine strength and toughness in the as-welded and post-weld heat-treated conditions. The inter-critical heat-affected zone (HAZ) had the lowest strength following thermal simulation, while the fine-grain and coarse-grain heat-affected zone exhibited increased strength when compared to the inter-critical HAZ. The toughness of the heat-affected zone in the as-simulated condition is lower than that of the base metal in all regions of the HAZ. Post-weld heat treatments (PWHTs) increased the toughness of the HAZ, but at the expense of strength. In addition, certain combinations of PWHTs within specific HAZ regions exhibited low toughness caused by tempered martensite embrittlement or intergranular failure. Synchrotron X-ray diffraction data have shown that Eglin steel has retained austenite in the fine-grain HAZ in the as-simulated condition. In addition, alloy carbides (M23C6, M2C, M7C3) have been observed in the diffraction spectra for the fine-grain and coarse-grain HAZ following a PWHT of 973 K (700 °C)/4 hours.

  17. New paleoseismic data from the northern San Jacinto Fault Zone, southern California

    Science.gov (United States)

    Onderdonk, N.; McGill, S. F.; Marliyani, G. I.; Rockwell, T. K.

    2010-12-01

    We present results from a new paleoseismic site along the Claremont strand of the San Jacinto Fault Zone in southern California. The site is located along the northeast edge of the ephemeral Mystic Lake at the north end of the San Jacinto Valley step-over. A small-scale (300 m wide) releasing step-over along the Claremont fault has created a sag depression that can be seen in early aerial photography. In 2009 an initial locator trench was excavated 400 m across the full width of this sag, exposing multiple faults and a structural depression filled with excellent shallow lake stratigraphy. Three additional trenches were excavated in 2010 across the main active fault zone that bounds the southwest edge of the sag. This fault is expressed as a zone of progressively folded and displaced strata. Upward terminations, fissures, folding, and growth stratigraphy provide evidence for at least six events in the upper 2 meters of section that was exposed. The stratigraphic relationships suggest a model in which each surface rupture results in subsidence of the sag, followed by clay deposition as the sag is filled in, culminating in a weak surface soil. 14C dating of 19 samples (out of over 400 that have been collected) was used to develop a preliminary event chronology. The most recent rupture occurred after 1750 AD and the penultimate event occurred between 1502 AD and 1612 AD. There is evidence for a cluster of 3 earthquakes between 1026 AD and 1220 AD, and a sixth event between 620 AD and 864 AD. The timing of the three events around 800 to 1000 years ago coincides temporally with a cluster of three events that were recorded at the Wrightwood paleoseismic site on the Mojave segment of the San Andreas Fault (SAF). These three events have not been recognized at paleoseismic sites along the San Bernardino segment of the SAF south of the juncture with the San Jacinto Fault, which suggests that some events on the SAF may rupture southward down the San Jacinto Fault (or vice

  18. Variability in riparian zone potential and actual evapotranspiration in a 1st order agricultural catchment in Southern Ontario, Canada

    Directory of Open Access Journals (Sweden)

    M. C. English

    2002-02-01

    Full Text Available Micrometeorological and hydrological measurements were made over one growing season using automatic weather stations and weighing lysimeters at several locations within a multiple land-use agricultural catchment in Southern Ontario. This paper compares modelled potential evapotranspiration (PET and measured actual evapotranspiration (AET values obtained from the soil weighing lysimeters, and determines the spatial variability in riparian zone AET in a multiple land-use agricultural watershed in Southern Ontario. Two sites were chosen in two different riparian areas of the watershed, representing the surface conditions dominant in the upper and lower reaches of the basin. The results indicated that AET was higher in the northern end of the basin than in the southern portion of the basin, while the hydrological and energy balance components were similar at both sites. The causes of the different rates are attributed to the surrounding vegetation on adjacent fields and the differing wind regimes.

  19. Spatio-temporal analysis of smear-positive tuberculosis in the Sidama Zone, southern Ethiopia.

    Directory of Open Access Journals (Sweden)

    Mesay Hailu Dangisso

    Full Text Available Tuberculosis (TB is a disease of public health concern, with a varying distribution across settings depending on socio-economic status, HIV burden, availability and performance of the health system. Ethiopia is a country with a high burden of TB, with regional variations in TB case notification rates (CNRs. However, TB program reports are often compiled and reported at higher administrative units that do not show the burden at lower units, so there is limited information about the spatial distribution of the disease. We therefore aim to assess the spatial distribution and presence of the spatio-temporal clustering of the disease in different geographic settings over 10 years in the Sidama Zone in southern Ethiopia.A retrospective space-time and spatial analysis were carried out at the kebele level (the lowest administrative unit within a district to identify spatial and space-time clusters of smear-positive pulmonary TB (PTB. Scan statistics, Global Moran's I, and Getis and Ordi (Gi* statistics were all used to help analyze the spatial distribution and clusters of the disease across settings.A total of 22,545 smear-positive PTB cases notified over 10 years were used for spatial analysis. In a purely spatial analysis, we identified the most likely cluster of smear-positive PTB in 192 kebeles in eight districts (RR= 2, p<0.001, with 12,155 observed and 8,668 expected cases. The Gi* statistic also identified the clusters in the same areas, and the spatial clusters showed stability in most areas in each year during the study period. The space-time analysis also detected the most likely cluster in 193 kebeles in the same eight districts (RR= 1.92, p<0.001, with 7,584 observed and 4,738 expected cases in 2003-2012.The study found variations in CNRs and significant spatio-temporal clusters of smear-positive PTB in the Sidama Zone. The findings can be used to guide TB control programs to devise effective TB control strategies for the geographic areas

  20. A Topology Reorganization Scheme for Reliable Communication in Underwater Wireless Sensor Networks Affected by Shadow Zones

    Directory of Open Access Journals (Sweden)

    Mari Carmen Domingo

    2009-10-01

    Full Text Available Effective solutions should be devised to handle the effects of shadow zones in Underwater Wireless Sensor Networks (UWSNs. An adaptive topology reorganization scheme that maintains connectivity in multi-hop UWSNs affected by shadow zones has been developed in the context of two Spanish-funded research projects. A mathematical model has been proposed to find the optimal location for sensors with two objectives: the minimization of the transmission loss and the maintenance of network connectivity. The theoretical analysis and the numerical evaluations reveal that our scheme reduces the transmission loss under all propagation phenomena scenarios for all water depths in UWSNs and improves the signal-to-noise ratio.

  1. Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California

    Science.gov (United States)

    Llenos, Andrea L.; Michael, Andrew J.

    2016-01-01

    The Brawley seismic zone (BSZ), in the Salton trough of southern California, has a history of earthquake swarms and geothermal energy exploitation. Some earthquake rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea Geothermal Field (SSGF). We explore this issue by examining earthquake rate changes and interevent distance distributions in these fields. In Oklahoma and Arkansas, where considerable wastewater injection occurs, increases in background seismicity rate and aftershock productivity and decreases in interevent distance were indicative of fluid‐injection‐induced seismicity. Here, we test if similar changes occur that may be associated with fluid injection and extraction in geothermal areas. We use stochastic epidemic‐type aftershock sequence models to detect changes in the underlying seismogenic processes, shown by statistically significant changes in the model parameters. The most robust model changes in the SSGF roughly occur when large changes in net fluid production occur, but a similar correlation is not seen in the NBGF. Also, although both background seismicity rate and aftershock productivity increased for fluid‐injection‐induced earthquake rate changes in Oklahoma and Arkansas, the background rate increases significantly in the BSZ only, roughly corresponding with net fluid production rate increases. Moreover, in both fields the interevent spacing does not change significantly during active energy projects. This suggests that, although geothermal field activities in a tectonically active region may not significantly change the physics of earthquake interactions, earthquake rates may still be driven by fluid injection or extraction rates, particularly in the SSGF.

  2. Tectonic lineaments in the cenozoic volcanics of southern Guatemala: Evidence for a broad continental plate boundary zone

    Science.gov (United States)

    Baltuck, M.; Dixon, T. H.

    1984-01-01

    The northern Caribbean plate boundary has been undergoing left lateral strike slip motion since middle Tertiary time. The western part of the boundary occurs in a complex tectonic zone in the continental crust of Guatemala and southernmost Mexico, along the Chixoy-Polochic, Motogua and possibly Jocotan-Chamelecon faults. Prominent lineaments visible in radar imagery in the Neogene volcanic belt of southern Guatemala and western El Salvador were mapped and interpreted to suggest southwest extensions of this already broad plate boundary zone. Because these extensions can be traced beneath Quaternary volcanic cover, it is thought that this newly mapped fault zone is active and is accommodating some of the strain related to motion between the North American and Caribbean plates. Onshore exposures of the Motoqua-Polochic fault systems are characterized by abundant, tectonically emplaced ultramafic rocks. A similar mode of emplacement for these off shore ultramafics, is suggested.

  3. Subduction of the Tehuantepec oceanic fracture zone and the relationship with a seismic gap in southern Mexico

    Science.gov (United States)

    Constantin Manea, Vlad; Manea, Marina; Taras, Gerya; Valenzuela, Raul W.

    2016-04-01

    It is accepted that key constraints on the size and recurrence time of large subduction earthquakes originate from the degree of locking between the subducting and overriding plates. Since the interseismic locking degree is influenced by the rheological properties of crustal and mantle rocks, any variations along strike will result in significant changes in seismic behavior due to a change in frictional stability. Additionally, recent seismic studies show that the subduction of hydrothermally altered oceanic fracture zones induces strong pore-fluid pressure variations that control the degree of interseismic locking. The Mexico Subduction Zone (MSZ) is characterized by major along-strike changes in subduction geometry, as well as important structural variations of the incoming oceanic plate. One of the main tectonic features of the Cocos plate is the Tehuantepec fracture zone (FZ) that is currently subducting beneath southern Mexico. The analysis of seismicity revealed that the area around where Tehuantepec fracture zone is currently subducting is conspicuously quiet and considered a seismic gap. Here, no significant quake (Ms ≥ 7.0) has occurred in more than 100 years, and the origin of Tehuantepec Seismic Gap (TSG) has not been elucidated yet. Based on the dimensions of the Tehuantepec gap (125 km length and 80 km width), an earthquake of Mw = 8.0 may be possible. This study aims to shed some light on the relationship between the TSG with the subduction of Tehuantepec oceanic fracture zone. Previous studies show that the uppermost oceanic lithosphere beneath the Tehuantepec FZ is partially serpentinized due to seawater infiltrations along faults. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations specifically tailored for the subduction of the Tehuantepec FZ at MSZ we show that the weakened serpentinized fracture zone is partially scraped out in the forearc region because of its low strength and positive buoyancy

  4. Institutional landscapes affecting small-scale fishing in Southern Sri Lanka - legal pluralism and its socio-economic effects

    NARCIS (Netherlands)

    W.A.R. Wickramasinghe; M. Bavinck

    2015-01-01

    This paper demonstrates the variety of institutional arrangements affecting small-scale fishing in southern Sri Lanka, highlighting legal pluralism and focusing particularly on its consequences for livelihoods and resource conservation. Evidence derives from two landing centres in Hambantota Distric

  5. Analysis of laser ablation dynamics of CFRP in order to reduce heat affected zone

    Science.gov (United States)

    Sato, Yuji; Tsukamoto, Masahiro; Nariyama, Tatsuya; Nakai, Kazuki; Matsuoka, Fumihiro; Takahashi, Kenjiro; Masuno, Shinichiro; Ohkubo, Tomomasa; Nakano, Hitoshi

    2014-03-01

    A carbon fiber reinforced plastic [CFRP], which has high strength, light weight and weather resistance, is attractive material applied for automobile, aircraft and so on. The laser processing of CFRP is one of suitable way to machining tool. However, thermal affected zone was formed at the exposure part, since the heat conduction property of the matrix is different from that of carbon fiber. In this paper, we demonstrated that the CFRP plates were cut with UV nanosecond laser to reduce the heat affected zone. The ablation plume and ablation mass were investigated by laser microscope and ultra-high speed camera. Furthermore, the ablation model was constructed by energy balance, and it was confirmed that the ablation rate was 0.028 μg/ pulse in good agreement with the calculation value of 0.03 μg/ pulse.

  6. Critical zone weathering in the southern Sierra Nevada and Laramie Mountains imaged by seismic tomography

    Science.gov (United States)

    Hayes, J. L.; Holbrook, W. S.; Riebe, C. S.

    2011-12-01

    Near-surface variations in seismic velocity reflect differences in physical properties such as density and porosity, which in turn reflect differences in alteration of parent material by exposure to water and biologic activity. Here we present tomographic analysis of the extent of weathering from seismic refraction experiments at two areas underlain by granite: the Southern Sierra Critical Zone Observatory (SSCZO) in the fall of 2010 & 2011 and the Laramie Mountains in the spring of 2010. A 48-channel geophone array and hammer source was deployed in both surveys. In both areas seismic velocities suggest that weathering has progressed to depths of 10 m or more. When coupled with geochemical measurements of the degree of regolith weathering, these depths imply that the potential for subsurface water storage in regolith may be a larger component of the water budget than previously thought at the SSCZO. The velocity of granite bedrock was determined independently in both studies to be ~4 km/s by seismic experiments directly on outcropping granite. Two other ranges of seismic velocities seem consistent between the studies: a saprolite layer of chemically altered but still intact rock (2-4 km/s) and a regolith layer more altered than the underlying saprolite layer (<2 km/s). Using these parameters we tested hypotheses in two different granite-weathering environments. In the SSCZO a velocity-depth profile that crosses a water-saturated meadow and an adjoining forest reveal relatively low gradients in the first ten meters beneath the forest (0.75 km/s per 10 m) and higher gradients beneath the meadow (3 km/s per 10 m). From these observations, we hypothesize that the saturated meadow may provide a reducing environment that inhibits chemical weathering relative to better-drained, more oxidizing conditions in the forest. In the 1.4 Ga Sherman batholith of the Laramie Mountains we observe isolated outcrops of Lincoln Granite within the Sherman Granite. Two 0.5 km profiles

  7. Chlorophyll-a Variability in the Southern Ocean Mixed Layer and Euphotic Zone From Elephant Seals and Profiling Floats

    Science.gov (United States)

    Carranza, M. M.; Gille, S. T.; Franks, P. J. S.; Johnson, K. S.; Girton, J. B.

    2015-12-01

    The Southern Ocean contains some of the ocean's deepest mixed layers. Because deep mixed layers can transport phytoplankton below the euphotic zone, light levels depend on mixed-layer depth (MLD), and phytoplankton growth is hypothesized to be co-limited by iron and light. Estimates of Chl-a fluorescence, particle backscattering and hydrographic profiles collected by southern elephant seals, EM-APEX, and biogeochemical Argo floats are used to evaluate the extent to which MLD influences phytoplankton bloom development and the vertical structure of chlorophyll-a (Chl-a) in the Southern Ocean. We find that surface Chl-a (i.e., mean Chl-a for the upper light penetration depth) is a relatively good proxy of phytoplankton biomass (i.e., depth-integrated Chl-a) within the euphotic zone but gives an inadequate representation of biomass within the mixed layer, particularly in the summer. Although nearly vertically homogeneous Chl-a within the mixed layer prevails in seasonal mean profiles, subsurface Chl-a maxima are not uncommon from spring through fall. Deep Chl-a maxima that correlate with particle backscattering in summer and fall are found near the base of the mixed layer, closer to the nutrient maximum than the light maximum, suggesting that nutrient limitation (i.e., essentially iron) can play a greater role than light limitation in governing productivity.

  8. Can ocean acidification affect population dynamics of the barnacle Semibalanus balanoides at its southern range edge?

    Science.gov (United States)

    Findlay, Helen S; Burrows, Michael T; Kendall, Michael A; Spicer, John I; Widdicombe, Stephen

    2010-10-01

    The global ocean and atmosphere are warming. There is increasing evidence suggesting that, in addition to other environmental factors, climate change is affecting species distributions and local population dynamics. Additionally, as a consequence of the growing levels of atmospheric carbon dioxide (CO2), the oceans are taking up increasing amounts of this CO2, causing ocean pH to decrease (ocean acidification). The relative impacts of ocean acidification on population dynamics have yet to be investigated, despite many studies indicating that there will be at least a sublethal impact on many marine organisms, particularly key calcifying organisms. Using empirical data, we forced a barnacle (Semibalanus balanoides) population model to investigate the relative influence of sea surface temperature (SST) and ocean acidification on a population nearing the southern limit of its geographic distribution. Hindcast models were compared to observational data from Cellar Beach (southwestern United Kingdom). Results indicate that a declining pH trend (-0.0017 unit/yr), indicative of ocean acidification over the past 50 years, does not cause an observable impact on the population abundance relative to changes caused by fluctuations in temperature. Below the critical temperature (here T(crit) = 13.1 degrees C), pH has a more significant affect on population dynamics at this southern range edge. However, above this value, SST has the overriding influence. At lower SST, a decrease in pH (according to the National Bureau of Standards, pHNBs) from 8.2 to 7.8 can significantly decrease the population abundance. The lethal impacts of ocean acidification observed in experiments on early life stages reduce cumulative survival by approximately 25%, which again will significantly alter the population level at this southern limit. Furthermore, forecast predictions from this model suggest that combined acidification and warming cause this local population to die out 10 years earlier than

  9. A Low Velocity Zone along the Chaochou Fault in Southern Taiwan: Seismic Image Revealed by a Linear Seismic Array

    Directory of Open Access Journals (Sweden)

    Hsin-Chieh Pu

    2010-01-01

    Full Text Available The Chaochou fault is one of the major boundary faults in southern Taiwan where strong convergence has taken place between the Eurasian and Philippine Sea plates. The surface fault trace between the Pingtung plain and the Central Range follows a nearly N-S direction and stretches to 80 km in length. In order to examine the subsurface structures along the Chaochou fault, a linear seismic array with 14 short-period stations was deployed across the fault to record seismic data between August and December 2001. Detailed examination of seismic data generated by 10 local earthquakes and recorded by the linear array has shown that the incidence angles of the first P-waves recorded by several seismic stations at the fault zone were significantly larger than those located farther away from the fault zone. This difference might reflect the lateral variation of velocity structures across the Chaochou fault. Further examination of ray-paths of seismic wave propagation indicates that a low-velocity zone along the Chaochou fault is needed to explain the significant change in incidence angles across the fault zone. Although we do not have adequate information to calculate the exact geometry of the fault zone well, the variation in incidence angles across the fault can be explained by the existence of a low-velocity zone that is about 3 km in width on the surface and extends downward to a depth of 5 km. The low-velocity zone along the Chaochou fault might imply that the fault system consists of several splay faults on the hanging wall in the Central Range.

  10. Indices based on silicoflagellate assemblages offer potential for paleo-reconstructions of the main oceanographic zones of the Southern Ocean

    Science.gov (United States)

    Rigual-Hernández, Andrés S.; Trull, Thomas W.; McCartney, Kevin; Ballegeer, Anne-Marie; Lawler, Kelly-Anne; Bray, Stephen G.; Armand, Leanne K.

    2016-08-01

    This study reports detailed silicoflagellate assemblage composition and annual seasonal flux from sediment traps at four locations along a transect across the Southern Ocean frontal systems. The four traps sampled the central Subantarctic Zone (SAZ, 47°S site), the Subantarctic Front (SAF, 51°S site), the Polar Frontal Zone (54°S site) and the Antarctic Zone (61°S site) across the 140°E longitude. Annual silicoflagellate fluxes to the deep ocean exhibited a similar latitudinal trend to those of diatom fluxes reported in previous work, with maxima in the Antarctic Zone and minima in the Subantarctic Zone. The data suggest that, along with diatoms, silicoflagellates are important contributors to biogenic silica export at all sites, particularly in the Subantarctic Zone. Two main silicoflagellate genera were observed, with Stephanocha sp. (previously known as Distephanus) dominating polar waters and Dictyocha sp. important in sub-polar waters. This is consistent with previous use of the Dictyocha / Stephanocha ratio to infer paleotemperatures and monitor shifts in the position of the Polar Frontal Zone in the sedimentary record. It appears possible to further refine the application of this approach by using the ratio between two Dictyocha species, because Dictyocha aculeata dominated at the Subantarctic Front, while Dictyocha stapedia dominated in the central Subantarctic Front. Given the well-defined environmental affinities of both species, a new SAF silicoflagellate index (SAF-SI) based on this ratio is proposed as a useful diagnostic for SAF and SAZ water mass signatures in the Plio-Pleistocene and Holocene sedimentary record.

  11. Effect of heat input on dilution and heat affected zone in submerged arc welding process

    Indian Academy of Sciences (India)

    Hari Om; Sunil Pandey

    2013-12-01

    Submerged arc welding (SAW) is a fusion joining process, known for its high deposition capabilities. This process is useful in joining thick section components used in various industries. Besides joining, SAW can also be used for surfacing applications. Heat Affected Zone (HAZ) produced within the base metal as a result of tremendous heat of arc is of big concern as it affects the performance of welded/surfaced structure in service due to metallurgical changes in the affected region. This work was carried out to investigate the effect of polarity and other SAW parameters on HAZ size and dilution and to establish their correlations. Influence of heat input on dilution and heat affected zone was then carried out. Four levels of heat input were used to study their effect on % dilution and HAZ area at both the electrode positive and electrode negative polarities. Proper management of heat input in welding is important, because power sources can be used more efficiently if one knows how the same heat input can be applied to get the better results. Empirical models have been developed using statistical technique.

  12. INTERBLOCK ZONES IN THE CRUST OF THE SOUTHERN REGIONS OF EAST SIBERIA: TECTONOPHYSICAL INTERPRETATION OF GEOLOGICAL AND GEOPHYSICAL DATA

    Directory of Open Access Journals (Sweden)

    K. Zh. Seminsky

    2015-09-01

    Full Text Available The zone-block structure of the lithosphere is represented by a hierarchically organized pattern of stable blocks and mobile zones which border such blocks and contain highly dislocated geological medium (Fig. 1. Today, different specialists adhere to different concepts of blocks and zones, which are two main elements of the lithosphere structure. Differences are most significant in determinations of ‘interblock zones’ that are named as deformation / destructive / contact / mobile / fracture zones etc. due to their diversity in different conditions of deformation. One of the most effective approaches to studying the zone-block structure of the lithosphere is a combination of geological and geophysical studies of interblock zones tectonic features on various scales, which can make it possible to reveal the most common patterns of the interblock zones, general regularities of their development and relationships between the interblock zones.The main objectives of our study were (1 to identify the zone-block structure of the crust in the southern regions of East Siberia from tectonophysical analysis of geological and geophysical surveys conducted on four different scales along the 500 km long Shertoy-Krasny Chikoy transect crossing the marginal segment of the Siberian block, the Baikal rift and the Transbaikalian block (Fig. 2; (2 to clarify structural features of the central part of the Baikal rift (representing the tectonic type of interblock extension zone by applying new research methods, such as radon emanation survey, to the Shertoy-Krasny Chikoy transect and using the previously applied methods, such as magnetotelluric sounding, on a smaller scale; and (3 to study manifestation of interblock zones of various ranks in different geological and geophysical fields, to reveal common specific features of their structural patterns for the upper crust, and to establish regularities of hierarchic and spatial relationships between the interblock

  13. A refinement of the chronology of rift-related faulting in the Broadly Rifted Zone, southern Ethiopia, through apatite fission-track analysis

    Science.gov (United States)

    Balestrieri, Maria Laura; Bonini, Marco; Corti, Giacomo; Sani, Federico; Philippon, Melody

    2016-03-01

    To reconstruct the timing of rift inception in the Broadly Rifted Zone in southern Ethiopia, we applied the fission-track method to basement rocks collected along the scarp of the main normal faults bounding (i) the Amaro Horst in the southern Main Ethiopian Rift and (ii) the Beto Basin in the Gofa Province. At the Amaro Horst, a vertical traverse along the major eastern scarp yielded pre-rift ages ranging between 121.4 ± 15.3 Ma and 69.5 ± 7.2 Ma, similarly to two other samples, one from the western scarp and one at the southern termination of the horst (103.4 ± 24.5 Ma and 65.5 ± 4.2 Ma, respectively). More interestingly, a second traverse at the Amaro northeastern terminus released rift-related ages spanning between 12.3 ± 2.7 and 6.8 ± 0.7 Ma. In the Beto Basin, the ages determined along the base of the main (northwestern) fault scarp vary between 22.8 ± 3.3 Ma and 7.0 ± 0.7 Ma. We ascertain through thermal modeling that rift-related exhumation along the northwestern fault scarp of the Beto Basin started at 12 ± 2 Ma while in the eastern margin of the Amaro Horst faulting took place later than 10 Ma, possibly at about 8 Ma. These results suggest a reconsideration of previous models on timing of rift activation in the different sectors of the Ethiopian Rift. Extensional basin formation initiated more or less contemporaneously in the Gofa Province (~ 12 Ma) and Northern Main Ethiopian Rift (~ 10-12 Ma) at the time of a major reorganization of the Nubia-Somalia plate boundary (i.e., 11 ± 2 Ma). Afterwards, rift-related faulting involved the Southern MER (Amaro Horst) at ~ 8 Ma, and only later rifting seemingly affected the Central MER (after ~ 7 Ma).

  14. Microstructural investigation of the heat-affected zone of simulated welded joint of P91 steel

    Directory of Open Access Journals (Sweden)

    T. Vuherer

    2013-07-01

    Full Text Available In the process of testing real components exposed to elevated temperature, it is not possible to neglect cracks. The most significant cracks can be induced by welding, which is applied for joining of structural components. Pressure equipment in service is also exposed to high pressure and high stresses. Materials for their manufacturing are designed to resist high stress at elevated temperature, and to meet requirements regarding creep resistance. The objective of this study is to investigate microstructure of different regions of the heat affected zone in T/P91 steels by using thermal simulation instead of welding.

  15. The effect of welding line heat-affected-zone on the formability of tube hydroforming process

    Science.gov (United States)

    ChiuHuang, Cheng-Kai; Hsu, Cheng-En; Lee, Ping-Kun

    2016-08-01

    Tube hydroforming has been used as a lightweight design approach to reduce CO2 emission for the automotive industry. For the high strength steel tube, the strength and quality of the welding line is very important for a successful tube hydroforming process. This paper aims to investigate the effect of the welding line's strength and the width of the heat-affected zone on the tube thinning during the hydroforming process. The simulation results show that both factors play an important role on the thickness distribution during the tube expansion.

  16. Does litterfall from native trees support rainfed agriculture? Analysis of Ficus trees in agroforestry systems of southern dry agroclimatic zone of Karnataka, southern India

    Institute of Scientific and Technical Information of China (English)

    B.Dhanya; Syam Viswanath; Seema Purushothaman

    2013-01-01

    Trees of the genus Ficus,integral components of indigenous rainfed agro-ecosystems of the southern dry agro-climatic zone of Kamataka,southern India,have traditionally been associated with the ecological service of soil quality enhancement in addition to various direct use benefits.We assessed the soil enrichment service of Ficus benghalensis L.a common Ficus species in these agroforestry systems,by quantifying nutrient return via litter fall.Litterfall estimation and chemical analysis of litter showed that F.benghalensis trees produce 3,512 kg·ha-1 of litter annually which,on decomposition,can satisfy up to 76.70 % of N,20.24% of P and 67.76% of K requirements of dryland crops annually per hectare.This can lead to an avoided cost of compost of US $ 36.46ha-1·a-1 in dryland farming systems.The slow rate of decay of Ficus litter,as revealed in litter decomposition studies indicates its potential as ideal mulch for dryland soils.We discuss the complementarity between Ficus litterfall and cropping patterns in Mandya,and its implications for rainfed agricultural systems.

  17. Average Stress Drops of Southern California Earthquakes in the Context of Crustal Geophysics: Implications for Fault Zone Healing

    Science.gov (United States)

    Hauksson, Egill

    2015-05-01

    To understand how fault healing processes affect earthquake stress drops, we search for a possible dependency of stress drops on crustal conditions and geophysical parameters. We reanalyze the stress drop values of ~60,000 earthquakes in southern California which were originally determined by Shearer et al. J Geophys Res 111:B06303, (2006) using a spectral method. We modify the dataset to include only stress drops that are derived from at least 10 spectra and with corner frequencies between 3 and 30 Hz, and correct the rupture velocity for increasing S-wave speed with depth. We see no dependence of stress drop on moment magnitude or depth, except for a small, poorly determined increase from 15 to 25 km. We use six crustal geophysics parameters to search for obvious correlations that may explain changes in the mean values of the stress drops: (1) crustal thickness, (2) isostatic gravity, (3) heat flow, (4) shear strain rate, (5) crustal stress regime, and (6) style of faulting. None of the variables reduce the scatter but most can explain up to 10-20 % variations in the mean stress drops. The geographical distribution of the grouped mean stress drops includes very high stress drops near Ridgecrest, eastern California, as well as near fault jogs within the San Andreas Fault system. Low stress drops dominate in trans-tensional regions. Heat flow and GPS-based shear strain rate estimates have the largest influence on stress drop variations. In the range of low to medium heat flow, the stress drops increase with increasing heat flow. In contrast, at high heat flow in thin crust, the stress drops decrease systematically with increasing heat flow. Increasing shear strain rate systematically correlates with decreasing stress drops. The crustal stress regime and style of faulting also influence the stress drops as demonstrated by lower stress drops for north-northeast trending principal horizontal stress and in areas of dip-slip faulting. The mean variations in stress drops

  18. Interseismic Lithospheric Response of the Southern End of the Cascadia Subduction Zone Following the 1992 Cape Mendocino Earthquake

    Science.gov (United States)

    Vermeer, J.; Hemphill-Haley, M. A.

    2014-12-01

    The Cascadia subduction zone (CSZ) in the Pacific Northwest where the pacific plate is subducting beneath the North American plate may be capable of producing M 9 earthquakes. At its southern end, the CSZ terminates at the Mendocino triple junction in northern California, a region of frequent seismic activity. The 1992 M 7.1 Cape Mendocino earthquake caused up to 1.4 m of measured coseismic deformation and it is thought to have been rupture of the southern end of the CSZ. I will present static GPS monument relocation data and the positions of intertidal organisms to measure the interseismic crustal deformation in the 22 years since the 1992 event. This evidence for post- and interseismic lithospheric response may show whether the earthquake was due to rupture of the southern end of the CSZ or a subsidiary fault. Because the megathrust has higher strain rates than subsidiary faults, we expect that significant interseismic deformation should have occurred if the 1992 earthquake was on the subduction zone interface. It will also provide an estimate of whether post-seismic recovery has been occurring since that event. Although the coseismic deformation was well documented via leveling and Vertical Extent of Mortality (VEM) of sessile intertidal organisms, no post seismic work had been done to measure the interseismic deformation. This study utilizes high resolution GPS observation of established benchmarks compared with the leveling from 1992 to measure the vertical change. It also compares elevation of specific intertidal organism colonies to the elevation of living organisms following the 1992 uplift as a proxy for relative sea level change. Quantifying the interseismic deformation allows us to better understand the source of the earthquake and how the upper plate is responding to strain accumulation along the subduction zone. Significant interseismic deformation would indicate that the fault may be reloading quickly and the earthquake was likely associated with

  19. In-situ Phase transformation study in fine grained heat affected zone of Grade 91 steels

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Sudarsanam Suresh [Ohio State University; Yamamoto, Yukinori [ORNL; Santella, Michael L [ORNL; Yu, Xinghua [ORNL; Komizo, Prof. Y [Osaka University; Terasaki, Prof. H [Osaka University

    2014-01-01

    Creep strength-enhanced ferritic (CSEF) steels such as the 9 Cr steel [ASTM A387 Grade 91] are widely used as tubing and piping in the new generation of fossil fired power plants. Microstructures in the fine-grained heat affected zone (FGHAZ) may significantly reduce creep strength leading Type IV failures. Current research suggest that reducing pre-weld tempering temperature from 760 C (HTT) to 650 C (LTT) has the potential to double the creep life of these welds. To understand this improvement, time-resolved X-ray diffraction (TRXRD) measurement with synchrotron radiation was used to characterize the microstructure evolution during fine grained heat-affected zone (HAZ) thermal cycling of grade 91 steel. The measurements showed both M23C6 (M=Fe, Cr) and MX (M=Nb, V; X=C,N) are present in the sample after the HTT condition. Near equilibrium fraction of M23C6 was measured in high temperature tempering condition (HTT, 760 C). However, the amount of M23C6 in LTT condition was very low since the diffraction peaks are close to the background. During simulated FGHAZ thermal cycling, the M23C6 partially dissolved in HTT sample. Interestingly, MX did not dissolve in both LTT and HTT samples. Hypothesis for correlation of M23C6 carbide distribution and pre-mature creep failure in FGHAZ will be made.

  20. A role for pre-collision processes in the origin of the aseismic zone of the southern Taiwan Central Range

    Science.gov (United States)

    Lewis, J. C.; Cavallotti, C. J.; Rau, R. J.

    2015-12-01

    Although Taiwan is one of the most seismically active areas on Earth, two areas on the island are notable for their lack of earthquakes, the coastal plain of central western Taiwan and an elongate area centered on the eastern flank of the southern Central Range. I focus on the latter area and suggest that pre-collision processes may have contributed to its development. Seismogenic strain offshore southeastern Taiwan reveals that the west side of the Luzon arc hosts a forearc sliver that was initially uplifted during basin inversion then tectonically thinned by pull-apart basin formation as collision initiated. This pre-collision history favors the tectonic insertion of a sliver of oceanic crust at depth in the orogenic suture zone. The presence of oceanic crust in this region is consistent with high seismic velocity observations as well as existing analog models. Strain inversions spanning the aseismic zone broadly show crustal thickening and NW-directed shortening to the east, and crustal thinning and SW-directed stretching to the west. Oceanic crust at depth could contribute to the aseismic zone by acting as a relatively strong body sandwiched between the accreted arc and weaker transitional continental crust to the west. In this scenario the aseismic zone is largely composed of forearc rocks that are not internally deforming by elastic deformation mechanisms. Alternatively the sliver may act as a west-pointing wedge (in profile view) that is promoting weaker transitional continental material to detach, imbricate or delaminate in front of the colliding continental promontory (i.e., the Peikang high) that appears to contribute to the low rates of seismicity in western Taiwan. In any of these latter scenarios it would be reasonable to expect changes in crustal architecture that might promote shallowing of the brittle-plastic transition as is observed around the aseismic zone. The specific mechanism for this shallowing remains unresolved and clearly the presence of

  1. Biochemical resistance of pyrogenic organic matter in fire-affected mineral soils of Southern Europe

    Science.gov (United States)

    Knicker, H.; González Vila, F. J.; Clemente Salas, L.

    2012-04-01

    Incorporated into the soil, naturally formed pyrogenic organic matter (PyOM) is considered as highly recalcitrant, but direct estimation of PyOM decomposition rates are scarce. With this aim in mind, we subjected organic matter (OM) of fire-affected and unaffected soils to biochemical degradation under laboratory conditions and monitored CO2 production over a period of seven months. The soils derived from fire affected and unaffected areas of the Sierra de Aznalcóllar and the Doñana National Park, Southern Spain. Virtual fractionation of the solid-state 13C nuclear magnetic resonance (NMR) spectra of the fire affected soils into fire-unaffected soil organic matter (SOM) and PyOM yielded charcoal C contributions of 30 to 50% to the total organic C (Corg) of the sample derived from the Aznalcóllar region. Fitting the respiration data with a double exponential decay model revealed a fast carbon flush during the first three weeks of the experiment. Solid-state 13C NMR spectroscopy evidenced the contribution of aromatic moieties of the PyOM to this initial carbon release and to the biosynthesis of new microbial biomass. The input of PyOM resulted in an increase of the mean residence time (MRT) of the slow OM pool of the soil by a factor of 3 to 4 to approximately 40 years which rises doubts rises doubts about the presumed big influence of PyOM as an additional C-sink in soils. On the other hand, although being small the difference in turnover rates is evident and has some major implication with respect to long-term alteration of the chemical composition of OM in fire-affected soils. Based on the obtained results and the analysis of PyOM in other soil systems, a conceptual model is presented which can explain the different behavior of PyOM under different soil conditions.

  2. Affected zone generated around the erosion pit on carbon steel surface at the incipient stage of vibration cavitation

    Institute of Scientific and Technical Information of China (English)

    CHEN HaoSheng; LI Jiang; LIU ShiHan; CHEN DaRong; WANG JiaDao

    2008-01-01

    The characteristics of erosion pits on a carbon steel surface were investigated at the incipient stage of cavitation erosion. After a 5-minute experiment performed in an ultrasonic vibration system, needle-like erosion pits appeared on the polished steel surface, and a specially affected zone was formed around the pit. The shape of the pit and the plastic deformation of the affected zone indicate that the me-chanical impaction on the surface is the main reason for the cavitation damage. On the other hand, the iridescent color, the decreased surface hardness and the precipitated carbides on the affected zone prove that the affected zone has experienced a tempering process with the temperature higher than 300℃. The lack of oxygen in the affected zone also proves that it is not a chemical oxygen result. A special phenomenon that a carbon ring forms in the affected zone is explained as a result of the tor-oidal bubbles' heating effect at the final stage of the bubble collapse.

  3. Different tree species affect soil respiration spatial distribution in a subtropical forest of southern Taiwan

    Science.gov (United States)

    Chiang, Po-Neng; Yu, Jui-Chu; Wang, Ya-nan; Lai, Yen-Jen

    2014-05-01

    Global forests contain 69% of total carbon stored in forest soil and litter. But the carbon storage ability and release rate of warming gases of forest soil also affect global climate change. Soil carbon cycling processes are paid much attention by ecological scientists and policy makers because of the possibility of carbon being stored in soil via land use management. Soil respiration contributed large part of terrestrial carbon flux, but the relationship of soil respiration and climate change was still obscurity. Most of soil respiration researches focus on template and tropical area, little was known that in subtropical area. Afforestation is one of solutions to mitigate CO2 increase and to sequestrate CO2 in tree and soil. Therefore, the objective of this study is to clarify the relationship of tree species and soil respiration distribution in subtropical broad-leaves plantation in southern Taiwan. The research site located on southern Taiwan was sugarcane farm before 2002. The sugarcane was removed and fourteen broadleaved tree species were planted in 2002-2005. Sixteen plots (250m*250m) were set on 1 km2 area, each plot contained 4 subplots (170m2). The forest biomass (i.e. tree height, DBH) understory biomass, litter, and soil C were measured and analyzed at 2011 to 2012. Soil respiration measurement was sampled in each subplot in each month. The soil belongs to Entisol with over 60% of sandstone. The soil pH is 5.5 with low base cations because of high sand percentage. Soil carbon storage showed significantly negative relationship with soil bulk density (p<0.001) in research site. The differences of distribution of live tree C pool among 16 plots were affected by growth characteristic of tree species. Data showed that the accumulation amount of litterfall was highest in December to February and lowest in June. Different tree species planted in 16 plots, resulting in high spatial variation of litterfall amount. It also affected total amount of litterfall

  4. Left-lateral transtension along the Tierra Colorada deformation zone, northern margin of the Xolapa magmatic arc of southern Mexico

    Science.gov (United States)

    Riller, U.; Ratschbacher, L.; Frisch, W.

    1992-05-01

    Structural analysis of steeply NNW-dipping tectonites along the northern margin of the Xolapa magmatic arc, southern Mexico, reveals progressive deformation involving ductile and brittle deformation mechanisms. Ductile deformation detached Cretaceous cover rocks from the Xolapa basement along a crustal-scale mylonite zone with normal fault geometry. Normal faults dissected the mylonite zone into blocks which rotated a minimum of 35° to the north. Stress tensors calculated from fault-striae data show subhorizontal, roughly N/S-trending principal extension. Deformation resulted from differential uplift of the Xolapa magmatic arc with respect to its northern hinterland (Mixteca terrane). The oblique normal fault geometry of the mylonites conforms with strike-slip and dip-slip movements along the faults. Left-lateral transtension commenced ductilely between 90 Ma (age of deformed cover rocks) and 34 Ma (U/Pb zircon age of an undeformed pluton cutting the mylonite zone) and continued brittlely into the late Tertiary (tilted Miocene volcanic rocks). We argue that deformation resulted from the interaction of a left-lateral strike-slip regime established during formation of the Caribbean, and an extensional collapse of the Xolapa magmatic arc resulting from a change in steady-state plate-boundary conditions in the early Tertiary.

  5. Miocene burial and exhumation of the India-Asia collision zone in southern Tibet: response to slab dynamics and erosion

    Science.gov (United States)

    Carrapa, Barbara; Orme, D.A.; DeCelles, Peter G.; Kapp, Paul; Cosca, Michael A.; Waldrip, R.

    2014-01-01

    The India-Asia collision zone in southern Tibet preserves a record of geodynamic and erosional processes following intercontinental collision. Apatite fission-track and zircon and apatite (U-Th)/He data from the Oligocene–Miocene Kailas Formation, within the India-Asia collision zone, show a synchronous cooling signal at 17 ± 1 Ma, which is younger than the ca. 26–21 Ma depositional age of the Kailas Formation, constrained by U-Pb and 40Ar/39Ar geochronology, and requires heating (burial) after ca. 21 Ma and subsequent rapid exhumation. Data from the Gangdese batholith underlying the Kailas Formation also indicate Miocene exhumation. The thermal history of the Kailas Formation is consistent with rapid subsidence during a short-lived phase of early Miocene extension followed by uplift and exhumation driven by rollback and northward underthrusting of the Indian plate, respectively. Significant removal of material from the India-Asia collision zone was likely facilitated by efficient incision of the paleo–Indus River and paleo–Yarlung River in response to drainage reorganization and/or intensification of the Asian monsoon.

  6. Heat affected zone (HAZ) hot cracking in 18 Cr.10 Ni stainless steels due to small boron content

    International Nuclear Information System (INIS)

    Boron lowers resistance to hot cracking in the heat affected zone of 18.10 Ti and 18.12 Mo stainless steels: this element brings down the temperature above which fusions occur. Those fusions occur in the metal when it is heated during welding. They concern a part of the heat affected zone which is all the more extended as the temperature at the start of the fusions is low, therefore as the boron content is high. Due to the welding strains, the zones in which the fusions occur get cracked

  7. Constraints on interseismic locking along the southern Cascadia subduction zone from historic and recent leveling and sea level observations

    Science.gov (United States)

    Burgette, R. J.; Weldon, R. J.; Schmidt, D. A.; Williams, T. B.

    2012-12-01

    The pattern of surface deformation along the Juan de Fuca-North American plate boundary provides a key constraint for inferring the distribution of interseismic locking along the interface of the subduction zone. The deformation is particularly complicated along the southern part of the Cascadia subduction zone, where the forearc is rotating and translating with respect to stable North America. This forearc motion makes it difficult to isolate the subduction component in the horizontal deformation field, whereas the vertical deformation field is dominated by elastic strain accumulating on the plate interface. Here we build upon our past work to add down-dip control by surveying two previously unrepeated leveling routes in southern Oregon and extend our full analysis of the historical data to the south end of Cascadia. Repeated high quality leveling data collected over the past century provide precise estimates of vertical displacement rates for benchmarks along highway routes. The leveling data are most diagnostic for the extent of locking where the leveling routes traverse down-dip. We have collected leveling data along two previously unrepeated routes that run perpendicular to the coast in southern Oregon. We repeated a 25 km portion of a National Geodetic Survey (NGS) first-order leveling route occupied in both 1930 and 1941 between the towns of Reedsport and Scottsburg. This line occupies a position near an inferred north-south transition in the depth of locking, based on previous modeling efforts. We also re-leveled 14 km of a 1942 NGS second-order line along the Chetco River east from Brookings, in southernmost Oregon. This route provides a trench-perpendicular transect along a portion of the margin where our current modeling of the locked zone is not well constrained. Preliminary results from our modern second-order digital leveling suggest we generally are able to obtain first-order misclosure (< 4 mm * √(km)) for double-run sections of 1.4-4 km length

  8. Structural evolution of the southern transfer zone of the Gulf of Suez rift, Egypt

    Science.gov (United States)

    Abd-Allah, Ali M. A.; Abdel Aal, Mohamed H.; El-Said, Mohamed M.; Abd El-Naby, Ahmed

    2014-08-01

    We present a detailed study about the initiation and reactivations of Zeit-El Tor transfer zone, south Gulf of Suez rift, and its structural setting and tectonic evolution with respect to the Cretaceous-Cenozoic tectonic movements in North Egyptian margin. NE trending zone of opposed-dipping faults (22 km wide) has transferred the NE and SW rotations of the sub-basins in central and south Gulf of Suez rift, respectively. The evolution of this zone started by reactivation of the NE oriented late Neoproterozoic fractures that controlled the occurrence of Dokhan Volcanics in the rift shoulders. Later, the Syrian Arc contraction reactivated these fractures by a sinistral transpression during the Late Cretaceous-Eocene time. N64°E extension of the Oligo-Miocene rift reactivated the NE fractures by a sinistral transtension. During this rifting, the NE trending faults forming the transfer zone were more active than the rift-bounding faults; the Upper Cretaceous reverse faults in the blocks lying between these NE trending faults were rotated; and drape-related reverse faults and the positive flower structures were formed. Tectonic inversion from contraction to extension controlled the distribution and thickness of the Upper Cretaceous-Miocene rocks.

  9. Spatial changes of Extended De Martonne climatic zones affected by climate change in Iran

    Science.gov (United States)

    Rahimi, Jaber; Ebrahimpour, Meisam; Khalili, Ali

    2013-05-01

    In order to better understand the effect associated with global climate change on Iran's climate condition, it is important to quantify possible shifts in different climatic types in the future. To this end, monthly mean minimum and maximum temperature, and precipitation from 181 synoptic meteorological stations (average 1970-2005) have been collected from the meteorological organization of Iran. In this paper, to study spatial changes of Iran's climatic zones affected by climate changes, Extended De Martonne's classification (originally formulated by De Martonne and extended by Khalili (1992)) was used. Climate change scenarios were simulated in two future climates (average conditions during the 2050s and the 2080s) under each of the SRES A1B and A2, for the CSIRO-MK3, HadCM3, and CGCM3 climate models. Coarse outputs of GCMs were downscaled by delta method. We produced all maps for three time periods (one for the current and two for the future) according to Extended De Martonne's classification. Finally, for each climatic zone, changes between the current and the future were compared. As the main result, simulated changes indicate shifts to warmer and drier zones. For example, in the current, extra arid-cold ( A1.1m2) climate is covering the largest area of the country (21.4 %), whereas in both A1B and A2 scenarios in the 2050s and the 2080s, extra arid-moderate ( A1.1m3) and extra arid-warm ( A1.1m4) will be the climate and will occupy the largest area of the country, about 21 and 38 %, respectively. This analysis suggests that the global climate change will have a profound effect on the future distribution of severe aridity in Iran.

  10. Lithospheric velocity model across the Southern Central Iberian Zone (Variscan Iberian Massif): The ALCUDIA wide-angle seismic reflection transect

    Science.gov (United States)

    Ehsan, Siddique Akhtar; Carbonell, Ramon; Ayarza, Puy; Martí, David; Martínez Poyatos, David; Simancas, José Fernando; Azor, Antonio; Ayala, Concepción; Torné, Montserrat; Pérez-Estaún, Andrés.

    2015-03-01

    A P wave seismic velocity model has been obtained for the Central Iberian Zone, the largest continental fragment of the Iberian Variscan Belt. The spatially dense, high-resolution, wide-angle seismic reflection experiment, ALCUDIA-WA, was acquired in 2012 across central Iberia, aiming to constrain the lithospheric structure and resolve the physical properties of the crust and upper mantle. The seismic transect, ~310 km long, crossed the Central Iberian Zone from its suture with the Ossa-Morena Zone to the southern limit of the Central System mountain range. The energy generated by five shots was recorded by ~900 seismic stations. High-amplitude phases were identified in every shot gather for the upper crust (Pg and PiP) and Moho (PmP and Pn). In the upper crust, the P wave velocities increase beneath the Cenozoic Tajo Basin. The base of the upper crust varies from ~13 km to ~20 km between the southernmost Central Iberian Zone and the Tajo Basin. Lower crustal velocities are more homogeneous. From SW-NE, the traveltime of PmP arrivals varies from ~10.5 s to ~11.8 s, indicating lateral variations in the P wave velocity and the crustal thickness, reflecting an increase toward the north related with alpine tectonics and the isostatic response of the crust to the orogenic load. The results suggest that the high velocities of the upper crust near the Central System might correspond to igneous rocks and/or high-grade metamorphic rocks. The contrasting lithologies and the increase in the Moho depth to the north evidence differences in the Variscan evolution.

  11. Study on laser welded heat-affected zone in new ultralow carbon bainitic steel

    Institute of Scientific and Technical Information of China (English)

    Lin Zhao; Wuzhu Chen; Xudong Zhang; Jiguo Shan

    2007-01-01

    800 MPa grade ultralow carbon bainitic (NULCB) steel is the recently developed new generation steel, which was produced by thermo mechanical controlled processing & relaxation-precipitation controlling transformation (TMCP&RPC) technique. The microstructure and the mechanical properties of the heat-affected zone (HAZ) in NULCB steel under laser welding conditions were investigated by using a Gleeble-1500 thermal simulator. The experimental results indicate that the simplex microstructure in the HAZ is granular bainite that consists of bainite-ferrite (BF) lath and M-A constituent when the cooling time from 800 to 500°C (t8/5) is 0.3-30 s, and the M-A constituent consists of twinned martensite and residual austenite. As t8/5 increases, the hardness and tensile strength of HAZ decreases, but they are higher than that of the base metal, indicating the absence of softened zone after laser welding. The impact toughness of HAZ increases at first and then decreases when tw increases. The impact energy of HAZ is much higher than that of the base metal when t8/5 is between 3 and 15 s. It indicates that excellent low temperature toughness can be obtained under appropriate laser welding conditions.

  12. The role of fault zone in affecting multiphase flow at Yucca Mountain

    International Nuclear Information System (INIS)

    Within Yucca Mountain, the potential High Level Nuclear-Waste Repository site, there are large scale fault zones, most notably the Ghost Dance Fault. The effect of such high-permeability, large-scale discontinuities on the flow and transport is a question of concern in assessing the ability of the site to isolate radio-nuclides from the biosphere. In this paper, we present a numerical study to investigate the role of the fault in affecting both the liquid and gas phase flows in the natural state at Yucca Mountain prior to waste emplacement, as well as after the waste emplacement when the fluid flow is strongly heat-driven. Our study shows that if the characteristic curves of the Ghost Dance Fault obey the same relationship between saturated permeability and capillary scaling parameter, is as observed from the measured data of Yucca Mountain welded and nonwelded tuffs, Apache Leap tuffs, and Las Cruces soil, then a large saturated permeability of the Ghost Dance Fault will play little role in channeling water into the fault, or in enhancing the flow of water down the fault. However, the Fault may greatly enhance the upward gas flow after emplacement of waste. This may have implications on the transport of gaseous radio-nuclides such as C14. The results of this study also focus attention on the need for field measurements of fluid flow in the fault zones

  13. The role of fault zones in affecting multiphase flow at Yucca Mountain

    International Nuclear Information System (INIS)

    Within Yucca Mountain, the potential High Level Nuclear-Waste Repository site, there are large scale fault zones, most notably the Ghost Dance Fault. The effect of such high-permeability, large scale discontinuities on the flow and transport is a question of concern in assessing the ability of the site to isolate radio-nuclides from the biosphere. In this paper, we present a numerical study to investigate the role of the fault in affecting both the liquid and gas phase flows in the natural state at Yucca Mountain prior to waste emplacement, as well as after the waste emplacement when the fluid flow is strongly heat-driven. Our study shows that if the characteristic curves of the Ghost Dance Fault obey the same relationship between saturated permeability and capillary scaling parameter, as is observed from the measured data of Yucca Mountain welded and nonwelded tuffs. Apache Leap tuffs, and Las Cruces soil, then a large saturated permeability of the Ghost Dance Fault will play little role in channeling water into the fault, or inenhancing the flow of water down the fault. However, the Fault may greatly enhance the upward gas flow after emplacement of waste. This may have implications on the transport of gaseous radio-nuclides such as C14. The results of this study also focus attention on the need for field measurements of fluid flow in the fault zones

  14. Microstructure and embrittlement of the fine-grained heat-affected zone of ASTM4130 steel

    Science.gov (United States)

    Li, Li-Ying; Wang, Yong; Han, Tao; Li, Chao-Wen

    2011-08-01

    The mechanical properties and microstructure features of the fine-grained heat-affected zone (FGHAZ) of ASTM4130 steel was investigated by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and welding thermal simulation test. It is found that serious embrittlement occurs in the FGHAZ with an 81.37% decrease of toughness, compared with that of the base metal. Microstructure analysis reveals that the FGHAZ is mainly composed of acicular, equiaxed ferrite, granular ferrite, martensite, and martensite-austenite (M-A) constituent. The FGHAZ embrittlement is mainly induced by granular ferrite because of carbides located at its boundaries and sub-boundaries. Meanwhile, the existence of martensite and M-A constituent, which distribute in a discontinuous network, is also detrimental to the mechanical properties.

  15. Subduction zone mantle enrichment by fluids and Zr-Hf-depleted crustal melts as indicated by backarc basalts of the Southern Volcanic Zone, Argentina

    Science.gov (United States)

    Holm, Paul M.; Søager, Nina; Alfastsen, Mads; Bertotto, Gustavo W.

    2016-10-01

    We aim to identify the components metasomatizing the mantle above the subducting Nazca plate under part of the Andean Southern Volcanic Zone (SVZ). We present new major and ICP-MS trace element and Sr, Nd and high-precision Pb isotope analyses of primitive olivine-phyric alkali basalts from the Northern Segment Volcanic Field, part of the Payenia province in the backarc of the Transitional SVZ. One new 40Ar-39Ar age determination confirms the Late Pleistocene age of this most northerly part of the province. All analysed rocks have typical subduction zone type incompatible element enrichment, and the rocks of the Northern Segment, together with the neighbouring Nevado Volcanic Field, have isotopic compositions intermediate between adjacent Transitional SVZ arc rocks and southern Payenia OIB-type basaltic rocks. Modelling the Ba-Th-Sm variation we demonstrate that fluids as well as 1-2% melts of upper continental crust (UCC) enriched their mantle sources, and La-Nb-Sm variations additionally indicate that the pre-metasomatic sources ranged from strongly depleted to undepleted mantle. Low Eu/Eu* and Sr/Nd also show evidence for a UCC component in the source. The contribution of Chile Trench sediments to the magmas seems insignificant. The Zr/Sm and Hf/Sm ratios are relatively low in many of the Northern Segment rocks, ranging down to 17 and 0.45, respectively, which, together with relatively high Th/U, is argued to indicate that the metasomatizing crustal melts were derived by partial melting of subducted UCC that had residual zircon, in contrast to the UCC melts added to Transitional SVZ arc magmas. Mixing between depleted and undepleted mantle, enriched by UCC and fluids, is suggested by Sr, Nd and Pb isotopes of the Northern Segment and Nevado magmas. The metasomatized undepleted mantle south of the Northern Segment is suggested to be part of upwelling OIB-type mantle, whereas the pre-metasomatically depleted mantle also can be found as a component in some arc

  16. Flavor of oranges as impacted by abscission zone formation for trees affected by huanglongbing disease and Lasiodiploida infection

    Science.gov (United States)

    Trees affected by Huanglongbing (HLB) exhibit excessive fruit drop, which is exacerbated by secondary infection of the abscission zone by the fungus Lasiodiplodia. ‘Hamlin’ orange trees, both healthy and affected by HLB, Candidatus Liberibacter asiaticus (CLas, determined by Polymerase chain reactio...

  17. Characterization of microstructure, local deformation and microchemistry in Alloy 690 heat-affected zone and stress corrosion cracking in high temperature water

    Science.gov (United States)

    Lu, Zhanpeng; Chen, Junjie; Shoji, Tetsuo; Takeda, Yoichi; Yamazaki, Seiya

    2015-10-01

    With increasing the distance from the weld fusion line in an Alloy 690 heat-affected zone, micro-hardness decreases, kernel average misorientation decreases and the fraction of Σ3 boundaries increases. Chromium depletion at grain boundaries in the Alloy 690 heat-affected zone is less significant than that in an Alloy 600 heat-affected zone. Alloy 690 heat-affected zone exhibits much higher IGSCC resistance than Alloy 600 heat-affected zone in simulated pressurized water reactor primary water. Heavily cold worked Alloy 690 exhibits localized intergranular stress corrosion cracking. The effects of metallurgical and mechanical properties on stress corrosion cracking in Alloy 690 are discussed.

  18. Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater Part 1: Southern and South Central Climate Zones

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Shen, Bo [ORNL; Keinath, Christopher M. [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City

    2016-01-01

    Commercial hot water heating accounts for approximately 0.78 Quads of primary energy use with 0.44 Quads of this amount from natural gas fired heaters. An ammonia-water based commercial absorption system, if fully deployed, could achieve a high level of savings, much higher than would be possible by conversion to the high efficiency nonheat-pump gas fired alternatives. In comparison with air source electric heat pumps, the absorption system is able to maintain higher coefficients of performance in colder climates. The ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. A thermodynamic model of a single effect ammonia-water absorption system for commercial space and water heating was developed, and its performance was investigated for a range of ambient and return water temperatures. This allowed for the development of a performance map which was then used in a building energy modeling software. Modeling of two commercial water heating systems was performed; one using an absorption heat pump and another using a condensing gas storage system. The energy and financial savings were investigated for a range of locations and climate zones in the southern and south central United States. A follow up paper will analyze northern and north/central regions. Results showed that the system using an absorption heat pump offers significant savings.

  19. NIR Tully-Fisher in the Zone of Avoidance. - II. 21 cm HI-line spectra of southern ZOA galaxies

    CERN Document Server

    Said, Khaled; Staveley-Smith, Lister; Williams, Wendy L; Jarrett, T H; Springob, Christopher M

    2016-01-01

    High-accuracy HI profiles and linewidths are presented for inclined ($(b/a)^o < 0.5$) spiral galaxies in the southern Zone of Avoidance (ZOA). These galaxies define a sample for use in the determinations of peculiar velocities using the near-infrared Tully-Fisher (TF) relation. The sample is based on the 394 HI-selected galaxies from the Parkes HI Zone of Avoidance survey (HIZOA). Follow-up narrow-band Parkes HI observations were obtained in 2010 and 2015 for 290 galaxies, while for the further 104 galaxies, sufficiently high signal-to-noise spectra were available from the original HIZOA data. All 394 spectra are reduced and parameterized in the same systematic way. Five different types of linewidth measurements were derived, and a Bayesian mixture model was used to derive conversion equations between these five widths. Of the selected and measure galaxies, 342 have adequate signal-to-noise (S/N $\\geq$ 5) for use in TF distance estimation. The average value of the signal-to-noise ratio of the sample is 14....

  20. Composition and structure of aggregates from compacted soil horizons in the southern steppe zone of European Russia

    Science.gov (United States)

    Sorokin, A. S.; Abrosimov, K. N.; Lebedeva, M. P.; Kust, G. S.

    2016-03-01

    The composition and structure of aggregates from different agrogenic soils in the southern steppe zone of European Russia have been studied. It is shown that the multi-level study (from the macro- to microlevel) of these horizons makes it possible to identify soil compaction caused by different elementary soil processes: solonetz-forming, vertisol-forming, and mechanical (wheel) compaction in the rainfed and irrigated soils. The understanding of the genesis of the compaction of soil horizons (natural or anthropogenic) is important for the economic evaluation of soil degradation. It should enable us to make more exact predictions of the rates of degradation processes and undertake adequate mitigation measures. The combined tomographic and micromorphological studies of aggregates of 1-2 and 3-5 mm in diameter from compacted horizons of different soils have been performed for the first time. Additional diagnostic features of negative solonetz- forming processes (low open porosity of aggregates seen on tomograms and filling of a considerable part of the intraped pores with mobile substance) and the vertisol-forming processes (large amount of fine intraaggregate pores seen on tomograms and a virtual absence of humus-clay plasma in the intraped zone)—have been identified. It is shown that the combination of microtomographic and micromorphological methods is helpful for studying the pore space of compacted horizons in cultivated soils.

  1. [CIRCULATION OF DIROFILARIA REPENS (RAILLIET ET HENRY, 1911) IN THE ARID ZONE OF SOUTHERN RUSSIA].

    Science.gov (United States)

    Varlamova, A I; Arkhipov, I A

    2016-01-01

    The prevalence of dirofilariasis was studied in dogs from the urban and rural areas in Southern Russia. The high prevalence of Dirofilaria repens infection were established among the dogs in the Republic of Kalmykia. The blood samples from 328 dogs were tested; D. repens infection was detected in 23.6 and 15.5% of the rural and urban dogs, respectively. The highest prevalence of D. repens infection was noted in of 4-6-year-old dogs. Dogs aged 0, 1-3, 4-6 7-9, and more 10 years were infected in 0, 26.3, 33.3, 29.4, and 28.5% of cases, respectively.

  2. Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes

    Science.gov (United States)

    Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.

    2016-01-01

    Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes within a highly modified, sediment-starved, 1.5-km2 salt marsh (Seal Beach) and a less modified 1-km2marsh (Mugu) with fluvial sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12,000 and 8800 kg in a western and eastern channel. Western channel storm imports offset 8700 kg exported during 2 months of dry weather, while eastern channel storm imports augmented 9200 kg imported during dry weather. During the storm at Mugu, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1–2 mm near creek levees. An exceptionally high tide sequence yielded 4.4 g/s mean sediment flux, importing 1700 kg: 20 % of Mugu’s dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are geomorphically stable during dry weather conditions. Results suggest storms and high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea level rise scenarios, results suggest that balanced sediment fluxes lead to marsh elevational instability based on estimated mineral sediment deficits.

  3. Initial Evaluation of the Heat-Affected Zone, Local Embrittlement Phenomenon as it Applies to Nuclear Reactor Vessels

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D.E.

    1999-09-01

    The objective of this project was to determine if the local brittle zone (LBZ) problem, encountered in the testing of the heat-affected zone (HAZ) part of welds in offshore platform construction, can also be found in reactor pressure vessel (RPV) welds. Both structures have multipass welds and grain coarsening along the fusion line. Literature was obtained that described the metallurgical evidence and the type of research work performed on offshore structure welds.

  4. Challenges to social capacity building in flood-affected areas of southern Poland

    Science.gov (United States)

    Działek, J.; Biernacki, W.; Bokwa, A.

    2013-10-01

    Various aspects of beliefs, behaviour and expectations of at-risk populations were analysed in four case study localities in southern Poland that were affected by flooding in 1997 and 2001. They represent localities of different sizes and are characterised by different paths of historical development. Two of them are deep-rooted communities with dense, strong family and neighbourhood ties, while the other two experienced an almost total replacement of their population due to decisions taken after World War II and still suffer from less developed social networks. Historical events also resulted in the disruption of local memories of flooding and transmission of knowledge about natural hazards. A questionnaire survey was conducted in late autumn 2006, followed by structured telephone interviews and focus group interviews in spring 2008. The results of the survey and interviews were analysed with reference to the social capacity framework and its five dimensions: knowledge, motivational, network, economic and governance capacities. Network capacities, that is resources of bonding and bridging social capital, were considered a key notion when analysing and interpreting the results. The differences in the local resources and abilities available in each of the localities to prepare a response to natural hazards were revealed. Consequently, challenges faced in the process of building and strengthening social capacity were identified as well as ways to address these challenges. It was concluded that there are general trends and tendencies that need to be considered in risk management strategies, however the different starting points of each case study community calls for different means and approaches, as well as producing somewhat different expected outcomes.

  5. Challenges to social capacity building in flood-affected areas of southern Poland

    Directory of Open Access Journals (Sweden)

    J. Działek

    2013-10-01

    Full Text Available Various aspects of beliefs, behaviour and expectations of at-risk populations were analysed in four case study localities in southern Poland that were affected by flooding in 1997 and 2001. They represent localities of different sizes and are characterised by different paths of historical development. Two of them are deep-rooted communities with dense, strong family and neighbourhood ties, while the other two experienced an almost total replacement of their population due to decisions taken after World War II and still suffer from less developed social networks. Historical events also resulted in the disruption of local memories of flooding and transmission of knowledge about natural hazards. A questionnaire survey was conducted in late autumn 2006, followed by structured telephone interviews and focus group interviews in spring 2008. The results of the survey and interviews were analysed with reference to the social capacity framework and its five dimensions: knowledge, motivational, network, economic and governance capacities. Network capacities, that is resources of bonding and bridging social capital, were considered a key notion when analysing and interpreting the results. The differences in the local resources and abilities available in each of the localities to prepare a response to natural hazards were revealed. Consequently, challenges faced in the process of building and strengthening social capacity were identified as well as ways to address these challenges. It was concluded that there are general trends and tendencies that need to be considered in risk management strategies, however the different starting points of each case study community calls for different means and approaches, as well as producing somewhat different expected outcomes.

  6. Biological valorisation of the southern Baltic Sea (Polish Exclusive Economic Zone

    Directory of Open Access Journals (Sweden)

    Jan Marcin Węsławski

    2009-09-01

    Full Text Available A biological valuation system to assess the value associated with ecosystem stability and richness (and not that from the point of view of users is proposed to provide scientific decision support for marine protected areas and marine spatial planning. The system is based on the assessment of individual species and habitat/species assemblages. An extensive set of recently collected (2007-08 and archival (1970-2000 data on the occurrence of marine benthos was analysed for the Polish Marine Areas. Based on matching data sets of sediments, the euphotic zone, temperature and salinity, as well as fetch and sea current values, a GIS model was used to visualise the results; a map indicates the two areas which are considered to be biologically the most valuable (Puck Bay and the stony shallows of the central coast.

  7. Paleoseismologic evidence for late Holocene earthquakes on the Southern Panamint Valley fault zone: Implications for earthquake clustering in the Eastern California Shear Zone north of the Garlock fault

    Science.gov (United States)

    McAuliffe, L. J.; Dolan, J. F.; Kirby, E.; Haravitch, B.; Alm, S.

    2010-12-01

    New paleoseismological data from two trenches excavated across the southern end of the Panamint Valley fault (PVF), the most active of the three major faults in the eastern California shear zone (ECSZ) north of the Garlock fault, reveal the occurrence of at least two, and probably three, surface ruptures during the late Holocene. These trenches were designed to test the hypothesis that the earthquake clusters and intervening seismic lulls observed in the Mojave section of the ECSZ (Rockwell et al. 2000, Ganev et al. 2010) at 8-9.5 ka, 5-6 ka and during the past ~1-1.5 ka, also involved the fault systems of the ECSZ north of the Garlock fault. Well stratified playa sands, silts and clays exposed in the trench allowed precise identification of two event horizons; a likely third event horizon occurred during a period of soil development across the playa. Calibrated radiocarbon dates from 25 charcoal samples constrain the dates of the most recent event (MRE) to ~1450-1500 AD and the ante-penultimate event at 3.2-3.6 ka. The penultimate event occurred during a period of soil development spanning ~350-1400 AD. The presence of large blocks of soil in what appears to be scarp-derived colluvium in a large fissure opened during this event require that it occurred late during soil development, probably only a few hundred years before the MRE. The timing of the three events indicate that the southern PVF has ruptured at least once, and probably twice during the ongoing seismic cluster in the Mojave region. The PVF earthquakes also are similar in age to the 1872 Owens Valley earthquakes and the geomorphically youthful, but undated MRE in central Death Valley. Although we were unable to excavate deeply enough at this site to expose mid-to lower - Holocene playa strata, the timing of the ante-penultimate earthquake at our site shows that the PVF has ruptured at least once during the well-defined 2-5 ka seismic lull in the Mojave section of the ECSZ. Interestingly the 3.2-3.6 ka

  8. The sound speed in southern deepwater zone of the Caspian Sea, off Anzali Port

    Science.gov (United States)

    Jamshidi, S.; Abu Bakar, N. B.

    2011-03-01

    Sound velocity determination in seawater is a key component of modern hydrographic surveying; however, little data exists on sound velocity characteristics of the southern Caspian Sea. Hence, a study was undertaken in 2008 to examine the seasonal variability of sound speed in deep-waters of the South Caspian Sea near the Iranian coast. The seasonal cycle of seawater temperature and thermal stratification in the Caspian Sea water created a wide range of spatial and temporal changes of sound speed with relevant differences between shallow water (over the continental shelf) and deep-water area. The collected data showed that seasonal variations of the sound speed were most important in the upper 100 m water depth, while below this level that is in deepwater the changes were small. The maximum values of sound speed were observed at the surface in midsummer around 1517-1519 m s-1 over the continental shelf while the speed of sound was about 1453 m s-1 between 450-470 m depths with no major seasonal variations. Variations in vertical structure of the sound speed were in agreement with temperature changes, while effects of the salinity on the sound speed were little.

  9. Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Martinez, D.I., E-mail: dorairma@yahoo.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Perez, A., E-mail: betinperez@hotmail.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Guajardo, H., E-mail: hguajardo@frisa.com [FRISA Aerospace, S.A. de C.V., Valentin G. Rivero No. 200, Col. Los Trevino, C.P. 66150, Santa Caterina N.L. (Mexico); Garza, A., E-mail: agarza@comimsa.com [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V. (COMIMSA), Ciencia y Tecnologia No.790, Saltillo 400, C.P. 25295 Saltillo Coah. (Mexico)

    2011-12-15

    The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy, specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.

  10. Effects of Notch Location on Heat-affected Zone Impact Properties of SA-516 Steels

    Science.gov (United States)

    Hong, Jaekeun; Park, Jihong; Kang, Chungyun

    In case of welding for pressure retaining parts on nuclear components, the verifications of heat affected zone (HAZ) impact properties are required according to application codes such as ASME Sec. III, RCC-M, KEPIC (Korea Electric Power Industry Code) MN, and JEA (Japan Electric Association) Code. Especially in case of Charpy V-notch tests of HAZ, the requirements of notch location and specimen direction have greatly impact on the reliability and consistency of the test results. For the establishment of newly adequate impact test requirements, the requirements about the HAZ impact tests of ASME Section III, RCC-M, KEPIC MN and JEA code were researched in this study. And also the HAZ impact test requirements about surveillance tests in nuclear reactor vessels were compared and investigated. For the effects of the notch location and specimen direction on the impact properties, SA-516 Gr.70 materials were investigated. The specimens were fabricated with using shielded metal-arc welding, and maximum heat inputs were controlled within the range of 16˜27 kJ/cm. Especially, this research showed the lateral expansion values and absorbed energies were not compatible and the impact test results were varied depending on notch location and specimen direction. Based on this study, newly adequate impact test requirements of HAZ were proposed.

  11. Austenite grain growth and microstructure control in simulated heat affected zones of microalloyed HSLA steel

    International Nuclear Information System (INIS)

    The roles of microalloying niobium, titanium and vanadium for controlling austenite grain growth, microstructure evolution and hardness were investigated at different simulated heat affected zones (HAZ) for high strength low alloy (HSLA) S690QL steel. High resolution FEG-SEM has been used to characterize fine bainitic ferrite, martensite and nanosized second phases at simulated coarse and fine grain HAZs. It was found that for Ti bearing steel (Ti/N ratio is 2) austenite grain had the slowest growth rate due to the presence of most stable TiN. The fine cuboidal particles promoted intragranular acicular ferrite (IGF) formation. Nb bearing steel exhibited relatively weaker grain growth retardation compared with titanium bearing steels and a mixed microstructure of bainite and martensite was present for all simulated HAZs. IGF existed at coarse grain HAZ of Ti+V bearing steel but it was totally replaced by bainite at fine grain HAZs. Hardness result was closely related to the morphology of bainitic ferrite, intragranular ferrite and second phases within ferrite. The microstructure and hardness results of different simulated HAZs were in good agreement with welded experimental results

  12. Austenite grain growth and microstructure control in simulated heat affected zones of microalloyed HSLA steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei [Department of Machine Tools and Factory Management, Technical University of Berlin, Pascalstraße 8 – 9, 10587, Berlin (Germany); Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin (Germany); Kannengiesser, Thomas [Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin (Germany); Institute of Materials and Joining Technology, Otto von Guericke University Magdeburg, Universitetsplatz 2, 39106, Magdeburg (Germany)

    2014-09-08

    The roles of microalloying niobium, titanium and vanadium for controlling austenite grain growth, microstructure evolution and hardness were investigated at different simulated heat affected zones (HAZ) for high strength low alloy (HSLA) S690QL steel. High resolution FEG-SEM has been used to characterize fine bainitic ferrite, martensite and nanosized second phases at simulated coarse and fine grain HAZs. It was found that for Ti bearing steel (Ti/N ratio is 2) austenite grain had the slowest growth rate due to the presence of most stable TiN. The fine cuboidal particles promoted intragranular acicular ferrite (IGF) formation. Nb bearing steel exhibited relatively weaker grain growth retardation compared with titanium bearing steels and a mixed microstructure of bainite and martensite was present for all simulated HAZs. IGF existed at coarse grain HAZ of Ti+V bearing steel but it was totally replaced by bainite at fine grain HAZs. Hardness result was closely related to the morphology of bainitic ferrite, intragranular ferrite and second phases within ferrite. The microstructure and hardness results of different simulated HAZs were in good agreement with welded experimental results.

  13. Imaging 3D seismic velocity along the seismogenic zone of Algarve region (southern Portugal)

    Science.gov (United States)

    Rocha, João.; Bezzeghoud, Mourad; Caldeira, Bento; Dias, Nuno; Borges, José; Matias, Luís.; Dorbath, Catherine; Carrilho, Fernando

    2010-05-01

    seismotectonic picture of the region. This work is expected to produce a more detailed knowledge of the structure of the crust over the region of Algarve, being able to identify seismogenic zones, potentially generators of significant seismic events and also the identification of zones of active faults.

  14. Mercury in particulate matter over Polish zone of the southern Baltic Sea

    Science.gov (United States)

    Beldowska, M.; Saniewska, D.; Falkowska, L.; Lewandowska, A.

    2012-01-01

    Important Hg transformations can occur at the air-water interface where polluted terrestrial air masses meet humid, halogen-rich marine air masses over the southern Baltic Sea. These chemical and physical processes include gas-to-particle conversion that led to an increase of Hg associated with coarse particles, which due to higher dry deposition rates, enhanced local scale deposition and limited the transport of this toxic trace metal. Daily (24 h) sampling of size-segregated atmospheric particles revealed the sea to be a sink for Hg during winter months and as a source of Hg during summer months. Poland is one of the major Hg emitters among the Baltic States according to International HELCOM Reports. Thus, important measurements in this region were conducted over a one-year period from December 18, 2007 to December 15, 2008. The range in concentrations of Hg in particulate matter (2-142 pg m -3) at the Polish site are comparable to other measurements at sites along the coastal areas of the Baltic Sea. Annual Hg(p) represents 1% of the total atmospheric Hg (Hg TOT) under unpolluted or background ambient conditions. A major source of atmospheric Hg in this area is the combustion of fossil fuels, especially coal burning used for home heating. This was clearly seen in the statistically higher mean concentration of 24 pg m -3 observed during the heating season compared to the 15 pg m -3 measured during the non-heating season. Construction activities e.g., cement manufacturing, gravel extraction, and waste incineration during the warm season strongly influenced Hg concentrations and led to an increase in Hg(p) on working days compared to weekend days.

  15. Human response and adaptation to drought in the arid zone: lessons from southern Africa

    Directory of Open Access Journals (Sweden)

    W. R.J. Dean

    2009-12-01

    Full Text Available Human adaptation and response to drought is primarily through evasion or endurance. A review of historical agricultural practices in southern Africa demonstrates evidence of drought evasion response strategies in well-established transhumance routes, where herders move livestock on a seasonal basis in order to exploit resources subject to different climatic regimes. European settlers to the arid regions of South Africa quickly recognised the necessity of these evasion options to survive drought, and adopted the transhumance practices of indigenous farmers. Areas of geographically diverse resource bases became hotly contested by settlers and indigenous farmers. The success of evasion systems are shown to hinge on good social and institutional support structures. When movement is not an option, drought endurance is pursued by attempting to limit the damage to the natural resource base. This is through a number of means such as forage conservation, varying livestock types and numbers, water and soil conservation and taking up alternative livelihood options. State responses to drought over the last century reflect the general South African pattern of racially divided and unjust policies relating to resource access. Historically the state provided considerable support to white commercial farmers. This support was frequently contradictory in its aims and generally was inadequate to enable farmers to cope with drought. Since the advent of democracy in 1994, the state has intervened less, with some support extended to previously disadvantaged and poor communal farmers. Climate change predictions suggest an increase in drought, suggesting that the adoption of mitigating strategies should be a matter of urgency. To do this South Africa needs to build social and institutional capacity, strive for better economic and environmental sustainability, embed drought-coping mechanisms into land restitution policy to ensure the success of this programme, and

  16. Podoconiosis and soil-transmitted helminths (STHs: double burden of neglected tropical diseases in Wolaita zone, rural Southern Ethiopia.

    Directory of Open Access Journals (Sweden)

    Bineyam Taye

    Full Text Available Both podoconiosis and soil-transmitted helminth (STH infections occur among barefoot people in areas of extreme poverty; however, their co-morbidity has not previously been investigated. We explored the overlap of STH infection and podoconiosis in Southern Ethiopia and quantified their separate and combined effects on prevalent anemia and hemoglobin levels in podoconiosis patients and health controls from the same area.A two-part comparative cross-sectional study was conducted in Wolaita zone, southern Ethiopia. Data were collected from adult patients presenting with clinically confirmed podoconiosis, and unmatched adult neighborhood controls living in the same administrative area. Information on demographic and selected lifestyle factors was collected using interviewer-administered questionnaires. Stool samples were collected and examined qualitatively using the modified formalin-ether sedimentation method. Hemoglobin level was determined using two different methods: hemoglobinometer and automated hematology analyzer. A total of 913 study subjects (677 podoconiosis patients and 236 controls participated. The prevalence of any STH infection was 47.6% among patients and 33.1% among controls (p<0.001. The prevalence of both hookworm and Trichuris trichiura infections was significantly higher in podoconiosis patients than in controls (AOR 1.74, 95% CI 1.25 to2.42, AOR 6.53, 95% CI 2.34 to 18.22, respectively. Not wearing shoes and being a farmer remained significant independent predictors of infection with any STH. There was a significant interaction between STH infection and podoconiosis on reduction of hemoglobin level (interaction p value = 0.002.Prevalence of any STH and hookworm infection was higher among podoconiosis patients than among controls. A significant reduction in hemoglobin level was observed among podoconiosis patients co-infected with hookworm and 'non-hookworm STH'. Promotion of consistent shoe-wearing practices may have

  17. Fault zone characteristics and basin complexity in the southern Salton Trough, California

    Science.gov (United States)

    Persaud, Patricia; Ma, Yiran; Stock, Joann M.; Hole, John A.; Fuis, Gary S.; Han, Liang

    2016-01-01

    Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.

  18. Heavy-metal pollution of sediments from the Polish exclusive economic zone, southern Baltic Sea

    Science.gov (United States)

    Szefer, P.; Glasby, G. P.; Geldon, J.; Renner, R. M.; Björn, E.; Snell, J.; Frech, W.; Warzocha, J.

    2009-04-01

    Analysis of 59 surface sediment samples from the Polish exclusive economic zone (EEZ) shows that Szczecin Lagoon sediments are the most polluted by heavy metals and that the degree of heavy-metal pollution decreases substantially on passing from the Szczecin Lagoon to the Pomeranian Bay and the inner shelf area and then on passing to the Bornholm Deep and Słupsk Furrow. Heavy-metal pollution in the sediments of the western part of the Polish EEZ therefore appears to follow the dispersion of the Oder River. Fluffy material from the Oder estuary appears to be the main source of heavy metals in the muddy sediments of the Bornholm Deep. The formation of sulphides is therefore not the principal factor controlling the enrichment of heavy metals in the sediments of this anoxic basin, although it may be responsible for the uptake of Mo, Sb and As. Two main factors control the distribution of the rare earth elements (REE) in sediments of the Polish EEZ: the input of Fe-organic colloids from rivers and the presence of detrital material in the sediments.

  19. Validation of Health Extension Workers Job Motivation Scale in Gamo-Gofa Zone, Southern Ethiopia: A Cross-Sectional Study.

    Science.gov (United States)

    Mohammed, Shikur; Tilahun, Marelign; Kote, Mesfin; Mama, Mohamedaman; Tamiru, Dessalegn

    2015-01-01

    Introduction. Well-trained and highly motivated community health workers are critical for delivery of community-based health care services. Understanding what motivates especially community health care providers for better community health requires the use of psychometrically reliable and valid scale. This study was conducted to validate job motivation scale in Gamo Gofa Zone, Southern Ethiopia. Methods. A cross-sectional study was conducted in 150 health care posts in Gamo Gofa Zone, from February 01, 2013, to March 01, 2013. A total of 301 participants responded to questionnaires asking about sociodemographic characteristics and job motivation. Exploratory factor analysis with principal component extraction and varimax with Kaiser Normalization rotation were employed to develop scales for job motivation. Eigenvalues greater than 1 were used as criterion of extraction. Items with item factor loadings less than 0.4 and double loaded items were dropped. Alpha and exploratory factor analyses were examined to test reliability and validity of the scale. Results. During exploratory factor analysis eight factors emerged from the three dimensions of job motivation scale, namely, educational career, workload, financial incentive, supervisor encouragement, community recognition, access to infrastructure, living condition, and better achievement in work. The factor loadings of the items in each dimension ranged from 0.58 to 0.83. Crobach's alpha of the scales ranged from 0.79 to 0.90. To check validities of the scales developed in this study, the previous studies conducted to develop job motivation scale were used. Conclusion. Although the present scale has the potential to measure the job motivation of health extension workers and it is low in cost and easy to administer and analyze, it should be field-tested at different settings.

  20. Structure and Local Seismicity From the Incoming Nazca Plate in the Southern Chile Subduction Zone

    Science.gov (United States)

    Scherwath, M.; Grevemeyer, I.; Flueh, E.; Contreras-Reyes, E.; Tilmann, F.; Kaul, N.; Weinrebe, W.

    2005-12-01

    Lithospheric deformation near the Chile Triple Junction is under investigation in the TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes) project. During R/V Sonne cruise SO181 (December 2004 to February 2005) various geophysical and geological data sets along several large transects across differently aged subducting oceanic lithosphere were acquired. TIPTEQ aims at studying the influence of the incoming plate on the seismogenic zone in the area of the 1960 great Chile earthquake (Mw=9.5), in particular the effects of the thermal regime (i.e., age).We compare structure and local seismicity on two of these transects, one where the incoming oceanic Nazca Plate was formed 6.5 Ma ago, the other 14.5 Ma in age at the trench, thus both of different thermal states. New magnetic data show that the older lithosphere was generated at a spreading rate of 40 mm/a compared to 25 mm/a for the younger one, yet the current convergence of both sections with the South American Plate is about the same (~80 mm/a). Bathymetric and vertical incidence seismic data show smooth and thicker sediments at the older transect whereas the rugged basement of the younger line is less covered, though the sedimentary thickness at the trench is ~2 km in both locations. The crust of the older transect is slightly thicker, shows a clear outer rise, and subducts at a slightly steeper angle than the younger line. On the latter, where the outer rise bulge has not yet been developed, the outer rise seismicity rate is higher and more concentrated in the crust. The local seismicity in the older region is less frequent and occurs predominantly in the upper mantle (see also Tilmann et al., this conference).

  1. Epizootological study of small ruminant gastrointestinal strongyles in Gamo-Gofa Zone, Southern Ethiopia.

    Science.gov (United States)

    Mohammed, Nejib; Taye, Messele; Asha, Amenu; Sheferaw, Desie

    2016-06-01

    The study was conducted with the objective to estimate the prevalence of gastrointestinal strongyles and identifying the prevailing strongyle species Gamo-Gofa Zone. A total of 598 animals (241 sheep and 357 goats) and 45 animals (20 sheep and 25 goats) were examined coproscopically and by post mortem, respectively. The overall coproscopic prevalence of strongylosis in the study area was 51.4 %. Strongyles were more prevalent in sheep than goats (95 % CI is 74.6-84.8 % and 58.6-68.6 % for sheep and goats, respectively; P < 0.05). A higher prevalence (P < 0.05) of strongyles infection was recorded in the midland and highland than the lowland, and in wet season than the dry season. The mean fecal egg count was found to be significantly higher (P < 0.05) in the midland area (908.7 ± 94.5) and in wet season (1,033.7 ± 84.2). The post mortem examination result indicated that the overall prevalence of gastrointestinal strongyles was 97.7 %; and a total of 11 strongyle species were identified of which Trichostrongylus axei, Teladorsagia species, Trichostrongylus colubriformis and Haemonchus contortus were the dominant and with higher load. During this study infection with multiple parasites, 3 and more 3, species were recorded in about 68 % goats and 85 % sheep. This study revealed the very high strongyle prevalence and higher proportion of multiple parasitism both in sheep and goats. Hence, it suggests the need to the institution of various control measures like strategic anthelmintic treatment for efficient utilization of the available small ruminant resources.

  2. The softened heat-affected zone in resistance spot welded tailor hardened boron steel: a material model for crash simulation

    NARCIS (Netherlands)

    Eller, T.K.; Greve, L.; Andres, M.T.; Medricky, M.; Geijselaers, H.J.M.; Meinders, V.T.; Boogaard, van den A.H.

    2016-01-01

    A hardness-based model for tailor hardened boron steel is presented that takes into account the softened heat-affected zone of resistance spot welds. The computational model is designed for crashworthiness simulation of fully and partially hardened components obtained by tailored tooling. Five diff

  3. Plasticity and fracture modeling of the heat-affected zone in resistance spot welded tailor hardened boron steel

    NARCIS (Netherlands)

    Eller, T.K.; Greve, L.; Andres, M.T.; Medricky, M.; Geijselaers, H.J.M.; Meinders, V.T.; Boogaard, van den A.H.

    2016-01-01

    tFive hardness grades of 22MnB5 are considered, covering the full strength-range from 600 MPa in theferritic/pearlitic range to 1500 MPa in the fully hardened, martensitic state. These five grades form thebasis for a hardness-based material model for the heat-affected zone found around resistance sp

  4. Factors Affecting Motivation and Job Satisfaction of Academic Staff of Universities in South-South Geopolitical Zone of Nigeria

    Science.gov (United States)

    Osakwe, Regina N.

    2014-01-01

    This study determined the factors affecting motivation and job satisfaction of non-management academic staff of universities in South-South geopolitical zone of Nigeria. It employed an expost-facto research design. Three research questions and two hypotheses were raised for the study. A sample of four hundred and fifty non-management academic…

  5. Upper plate deformation and seismic barrier in front of Nazca subduction zone: The Chololo Fault System and active tectonics along the Coastal Cordillera, southern Peru

    Science.gov (United States)

    Audin, Laurence; Lacan, Pierre; Tavera, Hernando; Bondoux, Francis

    2008-11-01

    The South America plate boundary is one of the most active subduction zone. The recent Mw = 8.4 Arequipa 2001 earthquake ruptured the subduction plane toward the south over 400 km and stopped abruptly on the Ilo Peninsula. In this exact region, the subduction seismic crisis induced the reactivation of continental fault systems in the coastal area. We studied the main reactivated fault system that trends perpendicular to the trench by detailed mapping of fault related-geomorphic features. Also, at a longer time scale, a recurrent Quaternary transtensive tectonic activity of the CFS is expressed by offset river gullies and alluvial fans. The presence of such extensional fault systems trending orthogonal to the trench along the Coastal Cordillera in southern Peru is interpreted to reflect a strong coupling between the two plates. In this particular case, stress transfer to the upper plate, at least along the coastal fringe, appears to have induced crustal seismic events that were initiated mainly during and after the 2001 earthquake. The seafloor roughness of the subducting plate is usually thought to be a cause of segmentation along subduction zones. However, after comparing and discussing the role of inherited structures within the upper plate to the subduction zone segmentation in southern Peru, we suggest that the continental structure itself may exert some feedback control on the segmentation of the subduction zone and thus participate to define the rupture pattern of major subduction earthquakes along the southern Peru continental margin.

  6. Coulomb Stress Change and Seismic Hazard of Rift Zones in Southern Tibet after the 2015 Mw7.8 Nepal Earthquake and Its Mw7.3 Aftershock

    Science.gov (United States)

    Dai, Z.; Zha, X.; Lu, Z.

    2015-12-01

    In southern Tibet (30~34N, 80~95E), many north-trending rifts, such as Yadong-Gulu and Lunggar rifts, are characterized by internally drained graben or half-graben basins bounded by active normal faults. Some developed rifts have become a portion of important transportation lines in Tibet, China. Since 1976, eighty-seven >Mw5.0 earthquakes have happened in the rift regions, and fifty-five events have normal faulting focal mechanisms according to the GCMT catalog. These rifts and normal faults are associated with both the EW-trending extension of the southern Tibet and the convergence between Indian and Tibet. The 2015 Mw7.8 Nepal great earthquake and its Mw7.3 aftershock occurred at the main Himalayan Thrust zone and caused tremendous damages in Kathmandu region. Those earthquakes will lead to significant viscoelastic deformation and stress changes in the southern Tibet in the future. To evaluate the seismic hazard in the active rift regions in southern Tibet, we modeled the slip distribution of the 2015 Nepal great earthquakes using the InSAR displacement field from the ALOS-2 satellite SAR data, and calculated the Coulomb failure stress (CFS) on these active normal faults in the rift zones. Because the estimated CFS depends on the geometrical parameters of receiver faults, it is necessary to get the accurate fault parameters in the rift zones. Some historical earthquakes have been studied using the field data, teleseismic data and InSAR observations, but results are in not agreement with each other. In this study, we revaluated the geometrical parameters of seismogenic faults occurred in the rift zones using some high-quality coseismic InSAR observations and teleseismic body-wave data. Finally, we will evaluate the seismic hazard in the rift zones according to the value of the estimated CFS and aftershock distribution.

  7. Late Quaternary Activity and Seismogenic Potential of the Gonave microplate: South Coast Fault Zone of Southern Jamaica

    Science.gov (United States)

    Benford, B.; Mann, P.; Prentice, C.; King, W.; Wiggins-Grandison, M.; Demets, C.; Tikoff, B.

    2008-12-01

    The South Coast fault zone (SCFZ) strikes east-west and forms a scarp as high as 600 m along the southern coast of Jamaica. It has been postulated that this fault acts as a left-lateral, strike-slip 'bypass' fault that truncates the large, right-stepping restraining bend formed between the Plantain Garden fault zone of southeastern Jamaica and the Duanvale-Walton fault zone of northwestern Jamaica. GPS measurements near the SCFZ show anomalously rotated vectors consistent with active left-lateral shear. Anomalous topography along the trace of the SCFZ includes two, doubly plunging anticlines: Kemp's Hill (119 m), an isolated high in the otherwise flat Vere Plain, and Round Hill (333 m), a larger high directly adjacent to the coast. Field work identified the most active trace of the SCFZ in a notch along the north flank of Round Hill; this trace can be extrapolated to the west along the coast and east that locally defines a low scarp in alluvium. Channel profiles constructed for six rivers and streams crossing the projected trace of the SCFZ show convex-upward morphologies, consistent with dominance of tectonic uplift over river downcutting. To better define the subsurface location of the SCFZ beneath the Vere Plain, a gravity survey network consisting of 327 stations and covering an areas of 500 km2 was performed using a Lacoste and Romberg G-meter. Differential GPS allowed centimeter-level elevation control for each station. Gravity corrections (elevation, latitude, instrument drift, and earth tides) were made using QC Tool software, and topographic and terrane corrections were made using both local topographic measurements and high-resolution SRTM data. An ~20 mgal negative gravity anomaly on the otherwise flat gravity field of the Vere Plain corresponds with the projected trace of the SCFZ across the Vere Plain and the locations of one river offset. We interpret that the SCFZ has down-to-the-south throw, which has led to thickening of Quaternary sediments south

  8. Evaluation of Heat-affected Zone Hydrogen-induced Cracking in High-strength Steels

    Science.gov (United States)

    Yue, Xin

    Shipbuilding is heavily reliant on welding as a primary fabrication technique. Any high performance naval steel must also possess good weldability. It is therefore of great practical importance to conduct weldability testing of naval steels. Among various weldability issues of high-strength steels, hydrogen-induced cracking (HIC) in the heat-affected zone (HAZ) following welding is one of the biggest concerns. As a result, in the present work, research was conducted to study the HAZ HIC susceptibility of several naval steels. Since the coarse-grained heat-affected zone (CGHAZ) is generally known to be the most susceptible to HIC in the HAZ region, the continuous cooling transformation (CCT) behavior of the CGHAZ of naval steels HSLA-65, HSLA-100, and HY-100 was investigated. The CGHAZ microstructure over a range of cooling rates was characterized, and corresponding CCT diagrams were constructed. It was found that depending on the cooling rate, martensite, bainite, ferrite and pearlite can form in the CGHAZ of HSLA-65. For HSLA-100 and HY-100, only martensite and bainite formed over the range of cooling rates that were simulated. The constructed CCT diagrams can be used as a reference to select welding parameters to avoid the formation of high-hardness martensite in the CGHAZ, in order to ensure resistance to hydrogen-induced cracking. Implant testing was conducted on the naval steels to evaluate their susceptibility to HAZ HIC. Stress vs. time to failure curves were plotted, and the lower critical stress (LCS), normalized critical stress ratio (NCSR) and embrittlement index (EI) for each steel were determined, which were used to quantitatively compare HIC susceptibility. The CGHAZ microstructure of the naval steels was characterized, and the HIC fracture behavior was studied. Intergranular (IG), quasi-cleavage (QC) and microvoid coalescence (MVC) fracture modes were found to occur in sequence during the crack initiation and propagation process. This was

  9. Heat affected zone microstructures and their influence on toughness in two microalloyed HSLA steels

    International Nuclear Information System (INIS)

    Microstructures and Charpy impact properties have been examined in two microalloyed steels following heat treatments to simulate weld heat affected zone (HAZ) structures over a range of heat input conditions, characterised by the cooling time from 800 to 500 °C (Δt8/5). The base materials were low carbon structural steel plates microalloyed with vanadium and nitrogen (V–N) and niobium (Nb), respectively. The toughnesses of the HAZs displayed remarkably different behaviours as shown by their impact transition temperatures. For the V–N steel, the toughness improved with increasingly rapid cooling (low heat input conditions) whereas the Nb steel showed an opposite trend. Some of this behaviour could be explained by the presence of coarse ferrite grains in the slowly cooled V–N steel. However, other conditions where all the structures were bainitic and rather similar in optical micrographs gave widely different toughness values. The recently developed method of five dimensional boundary analysis based on electron backscattering diffraction has been applied to these cases for the first time. This showed that the lath boundaries in the bainite were predominantly on {1 1 0} planes of the ferrite and that the average spacing of these boundaries varied depending on steel composition and cooling rate. Since {1 1 0} is also the slip plane in ferrite, it is considered that close spacing between the lath boundaries inhibits general plasticity at stress concentrations and favours initiation of fracture. The differences between the two steels are believed to be due to their transformation behaviours on cooling where precipitation of vanadium nitride in austenite accelerates ferrite formation and raises the temperature of the phase transformation in V–N steels.

  10. MICROSTRUCTURE AND MECHANICAL PROPERTY DEVELOPMENT IN THE SIMULATED HEAT AFFECTED ZONE OF V TREATED HSLA STEELS

    Institute of Scientific and Technical Information of China (English)

    Y.T. Chen; A.M. Guo; L.X. Wu; J. Zeng; P.H. Li

    2006-01-01

    The simulated heat affected zone (HAZ) of the high strength low alloy (HSLA) steels containing 0%, 0.047%, 0.097% and 0.151% vanadium, respectively, were studied with Gleeble-2000 thermomechanical simulator to determine the influence of vanadium addition on the mechanical properties of the HAZ. The HAZ simulation involved reheating the samples to 1350℃, and then cooling to ambient temperature at a cooling rate of 5℃/s ranging from 800 to 500℃ (△t8/5=60s).The mechanical properties including tensile strength and -20℃ impact toughness were conducted. The microstructures of the base steel and the simulated HAZs were investigated using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM).Basedon the systematic examination, the present work confirmed that about 0.05% vanadium addition to low carbon low alloy steels resulted in expected balance of strength and toughness of the HAZ. And more than 0.10% levels addition led to detrimental toughness of the HAZ. SEM study showed that the simulated 0.097% and 0.151%V HAZs consisted of more coarse ferrite plates with greater and more M-A constituents along austenite grain and ferrite plate boundaries. The impact fracture surfaces of the simulated 0.097% and 0.151% V HAZs showed typically brittle mode with predominant cleavages. The size of the facet in the fracture surface increased with increasing vanadium level from 0.097% to 0.151%. As a result, the simulated 0.151% V HAZ has the lowest impact toughness of the four specimens.

  11. Correlation Studies of Rare Earth Elements in Syntectonic Intrusions of Strike-Slip Stage along Southern Segment of Tan-Lu Fault Zone

    Institute of Scientific and Technical Information of China (English)

    Niu Manlan; Zhu Guang; Liu Guosheng; Song Chuanzhong

    2005-01-01

    Intrusions in the Zhangbaling uplift zone and the eastern margin of the Dabie orogenic belt belong to the syntectonic intrusions developed during the strike-slip stage in the southern segment of the Tan-Lu fault zone. However, characteristics of rare earth elements show that intrusions in the Zhangbaling uplift zone have the characteristics of mantle source type and those in the eastern margin of Dabie belt are the typical crust source type. Therefore, Au-deposits related to the intrusions in the Zhangbaling uplift zone are developed better than those in the eastern margin of the Dabieshan. The research results of the rare earth elements coincide with the studies of geophysics, tectonic setting and stable isotope. It is further indicated that the rare earth elements offer effective approach to tracing the material sources of magmatic rocks.

  12. Characteristics of climate chanse in the "significant impact zone" affected by aerosols over eastern China in warm seasonsthe East Asia region during warm seasons in recent 20 a and beyond as well as their possible interactive relationship with a variety

    Institute of Scientific and Technical Information of China (English)

    SHI XiaoHui; XU XiangDe; XIE LiAn

    2008-01-01

    Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac-tive relationship with a variety of meteorological elements, it is found that the high-value zone of aerosol optical depth derived from the Total Ozone Mapping Spectrometer (TOMS), its significant negative correlation zones in terms of sunshine duration (SD) and surface air temperature (SAT) and its significant positive correlation zones with low-level cloud amount (LCC) are co-located in the South China region during warm periods. Based on this finding, the region is referred to as a "significant impact zone" (SI zone) affected by aerosols. Then, a comparative analysis is made on variation differ-ences of observed SAT, SD and LCC, etc. In different regions. It is also found that the LCC is increased and the SD is decreased within the "SI zone" over eastern China during the warm season. These characteristics are more evident than those beyond the zone, while the warming trend within the zone is evidently weaker than that outside it. Studies show that since recent 20 a, under the influence of aerosols, the LCC tend to increase substantially with a clear decrease of SD and an unnoticeable warming trend within the "SI zone". Comparing with the climate change beyond the zone, the difference is significant. Therefore, the effects of atmospheric aerosols on climate is possibly one of the contri-butions to the difference of climate change existed between the southern and northern parts of the Eastern China during a warm season.

  13. Analysis of Microstructural Changes in the Heat-Affected Zone and Fusion Zone of a Fiber Laser Welded DP980 Steel

    Science.gov (United States)

    Zhang, Jianqi; Khan, Abdul; Ojo, Olanrewaju A.; Zhou, Norman; Chen, Daolun

    2015-08-01

    Dual phase (DP) steels are designed to consist of hard martensite dispersed in a relatively soft ferrite matrix, which offers a favorable combination of high strength with good deformability. Fiber laser welding (FLW) is becoming increasingly important for joining advanced materials due to its flexibility and deep penetration. In this study, the microstructure of a DP steel, DP980, welded by FLW technique was carefully analyzed. Gleeble thermo-mechanical simulation coupled with analytical transmission electron microscopy revealed that the FLW process produced significant microstructural changes in a narrow heat-affected zone (HAZ) and fusion zone (FZ), which can result in dramatic changes in mechanical properties. This is reflected in the micro-hardness profile obtained across the welded material. The salient phase transitions induced by the FLW, including the formation of new martensite grains in the upper-critical HAZ and FZ, are discussed.

  14. Extent of podoconiosis-related stigma in Wolaita Zone, Southern Ethiopia: a cross-sectional study.

    Science.gov (United States)

    Tora, Abebayehu; Franklin, Hannah; Deribe, Kebede; Reda, Ayalu A; Davey, Gail

    2014-01-01

    Studies have indicated that social stigma related to podoconiosis (endemic non-filarial elephantiasis) has a major impact on the psychosocial wellbeing of patients. However, little effort has been made so far to quantify the level of both felt and enacted stigma in a range of domains of life. We used a recently developed podoconiosis stigma assessment scale to measure levels of stigma as recalled over the previous 12 months. One hundred and fifty patients with podoconiosis rated the levels of stigma they perceived and experienced in 'interpersonal interactions', 'major life areas' and 'community, social and civic life'. High levels of stigma were observed on both felt and enacted stigma scales. The overall average stigma score was 40.7 (range 0 to 96). Enacted stigma was scored higher than felt stigma (mean score 21.2 vs. 19.5, respectively). The mean enacted stigma score was higher in 'major life areas', and 'community, social and civic life' than 'interpersonal interactions', while felt stigma was experienced most at the interpersonal level. Over half of patients reported that they had considered suicide in response to discrimination and prejudice, particularly in interpersonal interactions. Forced divorce, dissolution of marriage plan, insults and exclusion at social events were some of the most commonly mentioned forms of enacted stigma reported by affected individuals. Scores for overall level of stigma and enacted stigma increased significantly with stage of podoconiosis while the association observed in relation to felt stigma was only marginally significant (p = 0.085). Appropriate stigma reduction strategies must be identified and implemented in communities highly endemic for podoconiosis. PMID:25485190

  15. Extent of podoconiosis-related stigma in Wolaita Zone, Southern Ethiopia: a cross-sectional study.

    Science.gov (United States)

    Tora, Abebayehu; Franklin, Hannah; Deribe, Kebede; Reda, Ayalu A; Davey, Gail

    2014-01-01

    Studies have indicated that social stigma related to podoconiosis (endemic non-filarial elephantiasis) has a major impact on the psychosocial wellbeing of patients. However, little effort has been made so far to quantify the level of both felt and enacted stigma in a range of domains of life. We used a recently developed podoconiosis stigma assessment scale to measure levels of stigma as recalled over the previous 12 months. One hundred and fifty patients with podoconiosis rated the levels of stigma they perceived and experienced in 'interpersonal interactions', 'major life areas' and 'community, social and civic life'. High levels of stigma were observed on both felt and enacted stigma scales. The overall average stigma score was 40.7 (range 0 to 96). Enacted stigma was scored higher than felt stigma (mean score 21.2 vs. 19.5, respectively). The mean enacted stigma score was higher in 'major life areas', and 'community, social and civic life' than 'interpersonal interactions', while felt stigma was experienced most at the interpersonal level. Over half of patients reported that they had considered suicide in response to discrimination and prejudice, particularly in interpersonal interactions. Forced divorce, dissolution of marriage plan, insults and exclusion at social events were some of the most commonly mentioned forms of enacted stigma reported by affected individuals. Scores for overall level of stigma and enacted stigma increased significantly with stage of podoconiosis while the association observed in relation to felt stigma was only marginally significant (p = 0.085). Appropriate stigma reduction strategies must be identified and implemented in communities highly endemic for podoconiosis.

  16. Factors affecting carbon-14 activity of unsaturated zone CO2 and implications for groundwater dating

    Science.gov (United States)

    Wood, Cameron; Cook, Peter G.; Harrington, Glenn A.; Meredith, Karina; Kipfer, Rolf

    2014-11-01

    Unsaturated zone processes may influence the carbon-14 (14C) activity of infiltrating groundwater and thus introduce error in derived groundwater residence times. However unsaturated zone 14C activities are rarely measured and there is little understanding of how they may vary spatially in a groundwater basin. In this study we measured 14C activity in unsaturated zone gas at five sites with different watertable depths (8.2-31.5 m) in the arid Ti Tree Basin, central Australia. We observed a relatively uniform decrease in 14C activity of unsaturated zone gas with depth at most sites, with variation in unsaturated zone depths leading to variation in 14C activities directly above the watertable at each site (ranging from 54 to 106 percent Modern Carbon (pMC)). Through modelling we show that the profiles are influenced by CO2 production at different depths from sources with different isotopic ratios, including production of ‘modern' CO2 in the root zone and production of ‘old' CO2 above the watertable. Scenario modelling showed that these processes are independent of recharge when recharge is low (0-10 mm y-1) but that higher recharge rates (>100 mm y-1) result in more advective transport of atmospheric CO2 to the watertable. The variation in 14C above the watertable was more sensitive to watertable depth and shallow and deep CO2 production rates. These findings offer insight into how unsaturated zone 14C activities may vary spatially and provide guidance as to when 14C depletion in unsaturated zone CO2 may become important for groundwater dating, particularly in arid settings.

  17. Education in focus: impacts of school feeding program on school participation : a case study in Dara Woreda of Sidama Zone, Southern Ethiopia

    OpenAIRE

    Dheressa, Desalegn Keba

    2011-01-01

    It has been claimed that School Feeding Programs increase school participation among poor and food insecure group of people. This study investigates if the program has significant positive impact on school enrollment, class attendance, and student drop-out patterns among primary school children in Dara Woreda of Sidama Zone, Southern Ethiopia. Data were collected from 102 households as well as 17 selected individual stakeholders. Household Questionnaire, Key Informant Interviews and Observati...

  18. Late summer particulate organic carbon export and twilight zone remineralisation in the Atlantic sector of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    F. Planchon

    2012-03-01

    Full Text Available During the Bonus-GoodHope (BGH expedition (Jan–Mar 2008 we studied the water column distribution of total 234Th and biogenic particulate Ba (Baxs in the Atlantic sector of the Southern Ocean. The objective was to assess the export flux of particulate organic carbon (POC from the surface to the mesopelagic twilight zone along a section between the Cape Basin and Weddell Gyre. Export production of POC was estimated from steady state and non steady state export fluxes of 234Th which were converted into POC fluxes, using the POC/234Th ratio of large (>53 μm suspended particles, collected via in-situ pumps. Deficits in 234Th activities were observed at all stations from the surface to the bottom of the mixed-layer. 234Th export fluxes from the upper 100 m ranged from 496 ± 57 dpm m−2 d−1 to 1195 ± 120 dpm m−2 d−1 for the steady state model and from 149 ± 18 dpm m−2 d−1 to 1217 ± 146 dpm m−2 d−1 for the non steady state model calculated for a time window of 15 to 22 days preceding the timing of the present cruise. The POC/234Thp ratio of large, potentially sinking particles (>53 μm, was observed to increase with latitude, from 1.9 ± 0.2 μmol dpm−1 and 1.7 ± 0.3 μmol dpm−1 in the Subtropical Zone (STZ and Subantarctic Zone (SAZ, respectively, to 3.0 ± 0.2 μmol dpm−1 in the Polar Front Zone (PFZ, 4.8 ± 1.9 μmol dpm−1 at the Southern Antarctic Circumpolar Current Front (SACCF to 4.1 ± 1.7 μmol dpm−1 in the northern Weddell Gyre, in line with an increasing contribution of larger cell diatoms. Steady state and non steady state POC export from the upper 100 m ranged from 0.9 ± 0.2 mmolC m−2 d−1 to 5.1 ± 2.1 mmolC m−2 d−1 and

  19. The Importance of Southern Hemisphere CZOs for Evaluating Spatial Patterns of Chemical Structure in the Critical Zone and Assisting Human Development

    Science.gov (United States)

    Chadwick, O.

    2014-12-01

    The US Critical Zone Exploration Network (CZEN) is a network of sites designed to provide a better understanding of the integrated Earth surface system. The capacity of the critical zone to withstand perturbations, whether driven by climate, land use change, or spread of invasive species, depends on its chemical composition and physical state, which in turn depends on the time evolution of the critical zone. Many temperate and/or tectonically active critical zones contain a relatively short history due to rapid erosion but tectonically quiescent, tropical regions of the planet contain much longer records that need to be understood to cover the full suite of critical zone processes. Southern Hemisphere Critical Zone Observatories such as those proposed for Kruger National Park (KNP) in South Africa and for portions of the Yilgarn Craton in Western Australa will allow us to extend our temporal understanding of development of spatial heterogeneity in the chemical and physical structure of the critical zone. In addition to considering Earth and climate boundary conditions, these sites incorporate the roles that humans play in driving critical zone processes. For instance along the edges of KNP there is strong evidence of soil erosions due to periurbanization and small-scale agriculture. The existence of KNP provides an important contrast between a "natural" and "human-dominated" landscape that can be exploited to evaluate human impacts on critical zone resources and to develop targeted mitigation strategies. Western Australia has an exploitive economy that relies on large-scale agriculture and mineral extraction, both are intensive users of water which is scarce. The proposed CZO there will be partly focused on managing water under intense economic pressures. It is evident that if funding can be found for these sites they will enhance both critical zone science and practical applied science.

  20. Normalizing effect on fatigue crack propagation at the heat-affected zone of AISI 4140 steel shielded metal arc weldings

    Directory of Open Access Journals (Sweden)

    B. Vargas-Arista

    2013-01-01

    Full Text Available The fractography and mechanical behaviour of fatigue crack propagation in the heat-affected zone (HAZ of AISI 4140 steel welded using the shielded metal arc process was analysed. Different austenitic grain size was obtained by normalizing performed at 1200 °C for 5 and 10 hours after welding. Three point bending fatigue tests on pre-cracked specimens along the HAZ revealed that coarse grains promoted an increase in fatigue crack growth rate, hence causing a reduction in both fracture toughness and critical crack length, and a transgranular brittle final fracture with an area fraction of dimple zones connecting cleavage facets. A fractographic analysis proved that as the normalizing time increased the crack length decreased. The increase in the river patterns on the fatigue crack propagation in zone II was also evidenced and final brittle fracture because of transgranular quasicleavage was observed. Larger grains induced a deterioration of the fatigue resistance of the HAZ.

  1. The geometry of the Wadati-Benioff zone under southern Central America and its tectonic significance: results from a high-resolution local seismographic network

    Science.gov (United States)

    Protti, Marino; Gu¨ndel, Federico; McNally, Karen

    1994-07-01

    We present here a detailed geometry of the Wadati-Benioff zone under Costa Rica, obtained from seismicity recorded by a dense local seismographic network jointly operated by the Costa Rica Volcanological and Seismological Observatory, National University, and the Charles F. Richter Seismological Laboratory, University of California, Santa Cruz. Underneath the Nicaragua-Costa Rica border the Wadati-Benioff zone smoothly contorts (from steep to shallow dip angles, NW to SE), but does not show evidence of a brittle tear, as postulated by others. However, further to the SE, NE of Puerto Caldera, Costa Rica, the Wadati-Benioff zone does show a segmentation (the Quesada Sharp Contortion) at intermediate depths ( h > 70km). NW of this sharp contortion the deepest portion of the seismically active slab dips at about 80° and reaches maximum depths ranging from 200 km, near the Nicaragua-Costa Rica border, to 135 km under Ciudad Quesada. To the SE the deeper portion of the Wadati-Benioff zone dips at about 60° and the seismicity does not extend below depths ranging from 125 km, behind the volcanic arc, to 50 km, east of Quepos. In southern Costa Rica, east of 83°55'W, we find no evidence of the Wadati-Benioff zone deeper than 50 km. The obtained geometry and other known tectonic features related to the subduction of the Cocos plate under the Caribbean plate along the southern terminus of the Middle America Trench (Nicaragua and Costa Rica) correlate well with along-trench variations in age of the subducted Cocos plate. Some of these tectonic features are: (1) the shallowing of Middle America Trench bathymetry from NW to SE; (2) variations in the energy release within the subducted slab; (3) differences in coupling between Cocos and Caribbean plates; (4) the termination of the Central America Volcanic Chain in central Costa Rica; (5) distinct stress field variations on the overriding Caribbean plate. The subduction of the Cocos Ridge under southern Costa Rica is partially

  2. Mianlüe tectonic zone and Mianlüe suture zone on southern margin of Qinling-Dabie orogenic belt

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The Mianlue tectonic zone (Mianlue zone), an ancient suture zone in addition to theShangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianlue tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in theQinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring themountain-building orogenesis of the central orogenic system and the entire process of the majorChinese continental amalgamation during the Indosinian.

  3. Variability of Residence Time tracer Concentrations at the Southern Sierra Critical Zone Observatory during the California Drought

    Science.gov (United States)

    Visser, A.; Thaw, M.; Stacy, E.; Hunsaker, C. T.; Bibby, R. K.; Deinhart, A.; Schorzman, K.; Egnatuk, C. M.; Conklin, M. H.; Esser, B.

    2015-12-01

    California water supply from high elevation snow melt is vulnerable to climate change and prolonged drought conditions. Reduced snow pack and earlier snow melt will result in a greater reliance on man-made reservoirs and subsurface catchment storage. To gain insight into the subsurface storage volume of high elevation catchments, we studied the residence time distribution of surface water leaving the Southern Sierra Critical Zone Observatory. Since October 2014, we have collected monthly samples of two residence time tracers with contrasting half-lives: sulfur-35 (87.5 days) and tritium (12.32 years). Upstream catchment area at the three nested sampling locations is 1 km2 (P301 sub-catchment), 4 km2 (Providence Creek) and ~50 km2 (Big Creek). Samples were analyzed at LLNL by low level liquid scintillation counting and noble gas mass spectrometry after helium accumulation. Variations in tracer concentrations in precipitation, both for tritium (11-24 pCi/L) and sulfur-35 (24-100 mBq/L), complicate straightforward interpretation of residence times. Sulfur-35 concentrations show that last year precipitation contributes 1% - 10% of total stream flow, even during peak snowmelt. Tritium concentrations in stream flow vary between 40% and 60% of the initial concentration in precipitation (15.5 pCi/L), indicating that water leaving the catchment has a residence time on the order of years to decades. Additional analyses of sodium-22 (2.6 year half-life) will aid in deconvoluting the residence time distribution. These low tracer concentrations can be attributed to current severe drought conditions, resulting in low discharge rates and longer residence times. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-675107

  4. Impacts of land use change on nitrogen cycling archived in semiarid unsaturated zone nitrate profiles, southern High Plains, Texas.

    Science.gov (United States)

    Scanlon, Bridget R; Reedy, Robert C; Bronson, Kevin F

    2008-10-15

    Nitrate (NO3) profiles in semiarid unsaturated zones archive land use change (LUC) impacts on nitrogen (N) cycling with implications for agricultural N management and groundwater quality. This study quantified LUC impacts on NO3 inventories and fluxes by measuring NO3 profiles beneath natural and rainfed (nonirrigated) agricultural ecosystems in the southern High Plains (SHP). Inventories of NO3-N under natural ecosystems in the SHP normalized by profile depth are extremely low (2-10 kg NO3-N/ha/m), in contrast to those in many semiarid regions in the southwestern U.S. Many profiles beneath cropland (9 of 19 profiles) have inventories at depth that range from 28-580 kg NO3--N/ha/m (median 135 kg/ha/m) that correspond to initial cultivation, dated using soil water Cl. These inventories represent 74% (median) of the total inventories in these profiles. This NO3 most likely originated from cultivation causing mineralization and nitrification of soil organic nitrogen (SON) in old soil water (precultivation) and is attributed to enhanced microbial activity caused by increased soil wetness beneath cropland (median matric potential -42 m) relative to that beneath natural ecosystems (median -211 m). The SON source is supported by isotopes of NO3 (delta15N: +5.3 to +11.6; delta18O: +3.6 to +12.1). Limited data in South Australia suggest similar processes beneath cropland. Mobilization of the total inventories in these profiles caused by increased drainage/ recharge related to cultivation in the SHP could increase current NO3-N levels in the underlying Ogallala aquifer by an additional 2-26 mg/L (median 17 mg/L). PMID:18983076

  5. Factors affecting bond cement across casing leak zones in oil and gas wells

    Energy Technology Data Exchange (ETDEWEB)

    Nasr, Mohamed; Edbeib, Said [Al-Fateh University, Tripoli (Libyan Arab Jamahiriya). Dept. of Petroleum Engineering

    2004-07-01

    Casing leaks have been a major concern to the oil industry because of their effect on lowering the production rate in many oil and gas wells. The leaks are the result of deterioration of the casing in the well, which is caused by severe corrosion due to the contact of the casing with high salinity foreign fluid. The objective of this study is to determine the factors influencing the mechanical properties of the hardened cement opposite the casing leak zones. This study is conducted by laboratory measurements of the compressive strength of the hardened cement when the cement slurry was mixed with different percentages of formation water and different concentrations of different cement additives. The results of this study indicate that the compressive strength readings obtained from the cement bond log and the cement evaluation tool against the casing leak zones are lower than those readings recorded in adjacent formations. The low cement compressive strength values observed across casing leak zones are due to the contamination of the cement with saline water present in these formations which, in turn, effects the hardening properties of the cement. The experimental results indicated that the salinity of the formation water when mixed with the cement slurry in the presence of cement additives, decreased the compressive strength of the bond cement and also decreased the thickening time of the cement slurry. It is concluded that casing leaks found in many wells observed in oil fields in Libya were due to the mixing of the cement with high salinity formation water present in the lost circulation zones. The high water salinity in these zones effects the setting time of the cement slurry which, therefore, decreased the hardening properties of the bond cement and caused cracks and channels in the hardened cement across lost circulation zones. (author)

  6. Method for non-destructive measurement of heat affected zone of identification code on nuclear fuel rod

    International Nuclear Information System (INIS)

    In a method for the nondestructive measurement of the depth of the heat affected zone underneath a laser generated identification code on a nuclear fuel rod tube, the change in impedance of an electromagnetic foil produced by a portion of the tube is measured before and after the etching of a bar code is performed by use of laser power. The impedance change in the coil produced by the bar code-bearing tube portion is compared with the impedance change produced in the coil by the same tube portion before the bar code is generated thereon to determine whether a maximum allowed depth of the heat affected zone of the tube portion has been exceeded. (author)

  7. Altitudinal vs Latitudinal Climactic Drivers: A Comparison of a Relict Picea and Abies Forest in the Southern Appalachians versus the Hemi-Boreal Transition Zone off Southern Canada

    Science.gov (United States)

    Evans, A.; Lafon, C. W.

    2015-12-01

    Identification of biotic and abiotic determinants of tree species range limits is critical for understanding the effects of climate change on species distributions. Upward shifts of species distributions in montane areas have been widely reported but there have been few reports of latitudinal range retractions. Previous studies have indicated that southern latitudinal limits of a species range are dictated by biotic factors such as competition while others have suggested that abiotic factors, such as temperature, dictate these limits. We investigated the potential climatic gradients at the southern latitudinal limit of the Spruce (Picea) and Fir (Abies) species that dominate the Canadian boreal forest community as well as relict boreal forests containing similar species found in the high elevation areas of the Southern Appalachians. Existing research has suggested that relict ecosystems are more sensitive to climate change and can be indicative of future changes at latitudinal range limits. Expanding on this literature, we hypothesized that we would see similar gradients in climatic variables at the southern latitudinal limit of the Canadian boreal forest and those in the relict boreal forests southern Appalachians acting as controlling factors of these species distributions. We used forty years of climate data from weather stations along the southern edge of the boreal forest in the Canadian Shield provinces, species distribution data from the Canadian National Forest Inventory, (CNFI) geospatial data from the National Park Service (NPS), and historical weather data from the National Oceanic and Atmospheric Administration (NOAA) to perform our analysis. Our results indicate different climate variables act as controls of warm edge range limits of the Canadian boreal forest than those of the relict boreal forest of the southern Appalachians. However, we believe range retractions of the relict forest may be indicative of a more gradual response of similar species

  8. Effect of welding thermal cycles on the heat affected zone microstructure and toughness of multi-pass welded pipeline steels

    OpenAIRE

    Nuruddin, Ibrahim K.

    2012-01-01

    This research is aimed at understanding the effect of thermal cycles on the metallurgical and microstructural characteristics of the heat affected zone of a multi-pass pipeline weld. Continuous Cooling Transformation (CCT) diagrams of the pipeline steel grades studied (X65, X70 and X100) were generated using a thermo mechanical simulator (Gleeble 3500) and 10 mm diameter by 100 mm length samples. The volume change during phase transformation was studied by a dilatometer, this is to underst...

  9. Effects of neutron irradiation on the microstructure and mechanical properties of the heat affected zone of stainless steel welds

    OpenAIRE

    Stoenescu, Raluca

    2005-01-01

    The effects of neutron irradiation on austenitic stainless steels, usually used for the manufacturing of internal elements of nuclear reactors (e.g. the core shrouds), are the alteration of the microchemistry and the microstructure, and, as a consequence, of the mechanical properties. The present study is aimed at extending knowledge upon the impact of neutron-irradiation on the heat affected zone (HAZ) of welded materials, which was influenced by the thermal cycles upon fusion welding. Two t...

  10. Effects of neutron irradiation on the microstructure and mechanical properties of the heat affected zone of stainless steel welds

    OpenAIRE

    Stoenescu, Raluca; Baluc, Nadine Laurence

    2007-01-01

    The effects of neutron irradiation on austenitic stainless steels, usually used for the manufacturing of internal elements of nuclear reactors (e.g. the core shrouds), are the alteration of the microchemistry and the microstructure, and, as a consequence, of the mechanical properties. The present study is aimed at extending knowledge upon the impact of neutron-irradiation on the heat affected zone (HAZ) of welded materials, which was influenced by the thermal cycles upon fusion welding. Two t...

  11. Semi-automatic mapping of fault rocks on a Digital Outcrop Model, Gole Larghe Fault Zone (Southern Alps, Italy)

    Science.gov (United States)

    Mittempergher, Silvia; Vho, Alice; Bistacchi, Andrea

    2016-04-01

    A quantitative analysis of fault-rock distribution in outcrops of exhumed fault zones is of fundamental importance for studies of fault zone architecture, fault and earthquake mechanics, and fluid circulation. We present a semi-automatic workflow for fault-rock mapping on a Digital Outcrop Model (DOM), developed on the Gole Larghe Fault Zone (GLFZ), a well exposed strike-slip fault in the Adamello batholith (Italian Southern Alps). The GLFZ has been exhumed from ca. 8-10 km depth, and consists of hundreds of individual seismogenic slip surfaces lined by green cataclasites (crushed wall rocks cemented by the hydrothermal epidote and K-feldspar) and black pseudotachylytes (solidified frictional melts, considered as a marker for seismic slip). A digital model of selected outcrop exposures was reconstructed with photogrammetric techniques, using a large number of high resolution digital photographs processed with VisualSFM software. The resulting DOM has a resolution up to 0.2 mm/pixel. Most of the outcrop was imaged using images each one covering a 1 x 1 m2 area, while selected structural features, such as sidewall ripouts or stepovers, were covered with higher-resolution images covering 30 x 40 cm2 areas.Image processing algorithms were preliminarily tested using the ImageJ-Fiji package, then a workflow in Matlab was developed to process a large collection of images sequentially. Particularly in detailed 30 x 40 cm images, cataclasites and hydrothermal veins were successfully identified using spectral analysis in RGB and HSV color spaces. This allows mapping the network of cataclasites and veins which provided the pathway for hydrothermal fluid circulation, and also the volume of mineralization, since we are able to measure the thickness of cataclasites and veins on the outcrop surface. The spectral signature of pseudotachylyte veins is indistinguishable from that of biotite grains in the wall rock (tonalite), so we tested morphological analysis tools to discriminate

  12. Characterization of hole circularity and heat affected zone in pulsed CO2 laser drilling of alumina ceramics

    Science.gov (United States)

    Bharatish, A.; Narasimha Murthy, H. N.; Anand, B.; Madhusoodana, C. D.; Praveena, G. S.; Krishna, M.

    2013-12-01

    Circularity of drilled hole at the entry and exit, heat affected zone and taper are important attributes which influence the quality of a drilled hole in laser drilling. This paper examines the effect of laser parameters on the quality of drilled holes in Alumina ceramics which are widely used in microelectronic devices, based on orthogonal array experimentation and response surface methodology. Both entrance and exit circularities were significantly influenced by hole diameter and laser power. Heat affected zone was influenced by frequency. Taper was also significantly influenced by laser power. Response surface model predicted nominal entrance circularity at 2.5 kHz, 240 W, 2.5 mm/s, 1 mm hole, exit circularity and taper at 7.5 kHz, 240 W, 4.5 mm/s, and 1 mm hole. The model predicted lowest heat affected zone at 7.5 kHz, 240 W, 2.5 mm/s, and 1 mm. Multiobjective optimization achieved using both response surface model and gray relational analysis indicated that all the four quality parameters are optimized at 7.5 kHz, 240 W, 3.85 mm/s and 1 mm.

  13. Mechanisms affecting the infiltration and distribution of ethanol-blended gasoline in the vadose zone.

    Science.gov (United States)

    McDowell, Cory J; Powers, Susan E

    2003-05-01

    One- and two-dimensional experiments were conducted to examine differences in the behavior of gasoline and gasohol (10% ethanol by volume) as they infiltrate through the unsaturated zone and spread at the capillary fringe. Ethanol in the spilled gasohol quickly partitions into the residual water in the vadose zone and is retained there as the gasoline continues to infiltrate. Under the conditions tested, over 99% of the ethanol was initially retained in the vadose zone. Depending on the volume of gasoline spilled and the depth to the water table, this causes an increase in the aqueous-phase saturation and relative permeability, thus allowing the ethanol-laden water to drain into the gasoline pool. Under the conditions tested, the presence of ethanol does not have a significant impact on the overall size or shape of the resulting gasoline pool at the capillary fringe. Residual gasoline saturations in the vadose zone were significantly reduced however because of reduced surface and interfacial tensions associated with high ethanol concentrations. The flux of ethanol in the effluent of the column ranged from 1.4 x 10(-4) to 4.5 x 10(-7) g/(cm2 min) with the LNAPL and from 6 x 10(-3) to 3.0 x 10(-4) g/(cm2 min) after water was introduced to simulate rain infiltration. The experimental results presented here illustrate that the dynamic effects of ethanol partitioning into the aqueous phase in the vadose zone create an initial condition that is significantly different than previously understood.

  14. Deciphering heavy metal contamination zones in soils of a granitic terrain of southern India using factor analysis and GIS

    Indian Academy of Sciences (India)

    D Purushotham; Mahjoor Ahmad Lone; Mehnaz Rashid; A Narsing Rao; Shakeel Ahmed

    2012-08-01

    Soil contamination by heavy metals has been a major concern for last few decades due to increase in urbanization and industrialization. The main objective of this research was to identify the heavy metal contaminated zones in the study area. Twenty five soil samples collected throughout the agriculture, residential and industrial areas were analysed by X-ray Fluorescence Spectrometer (XRF) for trace metals and major oxides. These metals can affect the quality of soil and infiltrate through the soil, thereby causing groundwater pollution. Based on the chemical analysis of major oxides (SiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, TiO2, and P2O5) and their distribution; it is observed that these soils are predominantly siliceous type with slight enrichment of alumina component in the study area. Correlation matrix (CM) and factor analysis (FA) is employed to the heavy metal variables, viz., Ba, Cr, Cu, Ni, Pb, Rb, Sr, V, Y, Zn and Zr of the soil to determine the dominant factors contributing to the soil contamination in the area. In the analysis, five factors emerged as significant contributors to the soil quality. The total contribution of these five factors is about 90%. The contribution of the first factor is about 45% and has significant positive loadings of Co, Cr, Cu, Ni and Zn. The contribution of second factor is 22% and has significant positive loadings of Rb, Sr and Y. The contribution of third, fourth and fifth factors is 10, 8 and 5% and show positive loadings for lead, molybdenum and barium respectively to the soil contamination. The spatial variation maps deciphering different zones of heavy metal concentration in the soil were generated in a GIS (geographic information system) based environment using ArcGIS 9.3.1. The results reveal that heavy metal contamination in the area is mainly due to anthropogenic activities.

  15. Use of 87Sr/86Sr and δ11B to Identify Slag-Affected Sediment in Southern Lake Michigan

    Science.gov (United States)

    Bayless, Randall; Bullen, Thomas D.; Fitzpatrick, John A.

    2004-01-01

    Slag is a ubiquitous byproduct of the iron-smelting industry and influences geochemistry and water quality in adjacent geologic units, ground and surface water. Despite extensive slag deposition along the Indiana shoreline of Lake Michigan, definitive evidence that slag has affected lakebed sediments has not been established. Concerns for the protection of water and ecosystem resources in the Great Lakes motivated this study to determine if strontium and boron isotopes could be used to identify and delineate slag-affected bed sediment in Lake Michigan. Sixty-five samples of bed sediment were acquired from the southern lobe of Lake Michigan and analyzed for 87Sr/86Sr and ??11B. Samples immediately offshore from Indiana steel mills and slag-disposal sites contained higher median 87Sr/86Sr values (0.70881) than shoreline sediments collected elsewhere in the basin (0.70847) and uniquely decreased with increasing distance from the shoreline. The highest ??11B values occurred in sediments from the Indiana shoreline (+12.9 to 16.4???) but were also elevated in sediments collected offshore from three Lake Michigan cities (+11.7 to 12.7???). Contoured isotope data indicated that 82-154 km2 of bed sediment along the Indiana shoreline had elevated 87Sr/86Sr and ??11B values relative to shoreline sediments elsewhere in southern Lake Michigan.

  16. Factors affecting the income from major crops in rice-wheat ecological zone

    International Nuclear Information System (INIS)

    Agriculture is an important sector of our economy. About twenty-two percent of national income and 44.8 percent of total employment is generated by this sector. About 66 percent of country's population is living in rural areas and is directly or indirectly linked with agriculture for their livelihood. It also supplies raw materials to industry. The rice-wheat zone of Punjab covers 1.1 million hectare, 72% of wheat is grown in rotation with rice. The main purpose of this paper was to determine the effect of different factors on the productivity and ultimately on income from of major crops (wheat, rice and sugar-cane) in rice-wheat ecological zone. The results show that for wheat crop, land preparation, use of fertilizer and chemicals, for Sugarcane crop, area under cultivation, fertilizer and chemical costs and for rice crop, applications of chemicals, irrigation and land holding were the main determinants of productivity and crop income. (author)

  17. Factors affecting the seroprevalence of lagovirus infection in wild rabbits (Oryctolagus cuniculus) in Southern Spain.

    Science.gov (United States)

    García-Bocanegra, Ignacio; Astorga, Rafael J; Napp, Sebastián; Huerta, Belén; Carbonero, Alfonso; Perea, Anselmo; Arenas, Antonio

    2011-07-01

    Cross-sectional studies were carried out on wild rabbit (Oryctolagus cuniculus) populations in Southern Spain to assess the prevalence of lagovirus infection and to identify potentially associated risk factors. A total of 619 blood and 487 liver samples from wild rabbits were collected from seven hunting areas with different Mediterranean ecosystems. Logistic regression analysis was used to assess associations between seropositivity and an extensive set of variables. The seroprevalence was 29.2% (95% CI: 25.6-32.8) and lagoviruses were not detected in liver samples. Logistic regression indicated that seropositivity to lagoviruses was associated with seropositivity to myxomatosis, wild rabbit density, the existence of artificial feeding sites, mean maximum monthly temperatures of 20-30 °C, and annual accumulated rainfall of >600 mm. PMID:20643566

  18. Empowerment Zones and Enterprise Districts, Enterprise Zone in Quitman, Brooks County, GA, Published in 2008, 1:2400 (1in=200ft) scale, Southern Georgia Regional Commission.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Empowerment Zones and Enterprise Districts dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Other information as of 2008. It is...

  19. Empowerment Zones and Enterprise Districts, Enterprise Zone in Tifton, Tift County, GA, Published in 2008, 1:2400 (1in=200ft) scale, Southern Georgia Regional Commission.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Empowerment Zones and Enterprise Districts dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Other information as of 2008. It is...

  20. Empowerment Zones and Enterprise Districts, Enterprise Zone in Ocilla, Irwin County, GA, Published in 2008, 1:2400 (1in=200ft) scale, Southern Georgia Regional Commission.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Empowerment Zones and Enterprise Districts dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Other information as of 2008. It is...

  1. Empowerment Zones and Enterprise Districts, Enterprise Zone in Ashburn, Turner County, GA, Published in 2007, 1:2400 (1in=200ft) scale, Southern Georgia Regional Commission.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Empowerment Zones and Enterprise Districts dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Other information as of 2007. It is...

  2. Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile

    Directory of Open Access Journals (Sweden)

    Ernesto Moya-Elizondo

    2015-03-01

    Full Text Available Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L. crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W and Purranque (40°50'30" S; 73°22'03" W. Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile.

  3. Bimodal volcanism in a tectonic transfer zone: Evidence for tectonically controlled magmatism in the southern Central Andes, NW Argentina

    Science.gov (United States)

    Petrinovic, I. A.; Riller, U.; Brod, J. A.; Alvarado, G.; Arnosio, M.

    2006-04-01

    This field-based and analytical laboratory study focuses on the genetic relationship between bimodal volcanic centres and fault types of an important tectonic transfer zone in the southern Central Andes, the NW-SE striking Calama-Olacapato-Toro (COT) volcanic belt. More specifically, tectono-magmatic relationships are examined for the 0.55 Ma Tocomar, the 0.78 Ma San Jerónimo and the 0.45 Ma Negro de Chorrillos volcanic centres in the Tocomar area (66°30 W-24°15 S). Structures of the COT volcanic belt, notably NW-SE striking strike-slip faults and NE-SW trending normal faults, accommodated differential shortening between major N-S striking thrust faults on the Puna Plateau. We present evidence that bimodal volcanism was contemporaneous with activity of these fault types in the COT volcanic belt, whereby eruption and composition of the volcanic rocks in the Tocomar and San Jerónimo-Negro de Chorrillos areas appear to have been controlled by the kinematics of individual faults. More specifically, rhyolitic centres such as the Tocomar are associated with normal faults, whereas shoshonitic-andesitic monogenetic volcanoes, e.g., the San Jerónimo and Negro de Chorrillos centres, formed at strike-slip dominated faults. Thus, the eruption of higher viscous rhyolite magmas appears to have been facilitated in tectonic settings characterized by horizontal dilation whereas ascent and effusive volcanic activity of less viscous and hot basaltic andesites to shoshonites were controlled by subvertical strike-slip faults. While the Tocomar rhyolites are interpreted to be derived from an anatectic crustal source, geochemical characteristics of the San Jerónimo and Negro de Chorrillos shoshonitic andesites are in agreement with a deeper source. This suggests that the composition of erupted volcanic rocks as well as their spatial distribution in the Tocomar area is controlled by the activity of specific fault types. Such volcano-tectonic relationships are also evident from older

  4. Estimating CH4 emission from paddy managed soils in southern guinea savanna zone of Nigeria using an integrated approach

    Science.gov (United States)

    Akpeokhai, Agatha; Menz, Gunter; Thonfeld, Frank; Akinluyi, Francis

    2016-04-01

    ESTIMATING CH4 EMISSION FROM PADDY MANAGED SOILS IN SOUTHERN GUINEA SAVANNA ZONE OF NIGERIA USING AN INTEGRATED APPROACH Akpeokhai Agatha 1, Menz Gunter 1, Thonfeld Frank 1, Akinluyi Francis 2 1 Remote Sensing Research Group (RSRG), Geography Institute, University of Bonn, Germany. 2 Department Remote Sensing and Geo-Science Information System, School of Earth and Mineral Science, Federal University of Technology, Akure Nigeria. Methane is one of the most important greenhouse gases as it has the second greatest climate forcing potential. Paddy fields have been identified to be sources of methane and Nigerian paddies are not left out. In Nigeria, the guinea savanna region is regarded as the bread basket of the nation and this area is one of the major rice producing regions in Nigeria. Its location in the food basket region of the country makes this part a very important study site. However, since Nigerian paddies contribute to methane emission by how much do these paddies contribute to the emissions? Also, so far, there limited studies on methane from rice fields in West Africa thus making this study a very important start off point. To answer this huge question, methane emission will be estimated using an integrated approach in the North Central part of Nigeria. Land use change cultivated to rice was analysed using Remote sensing techniques to determine the changes in land cultivated to rice. Methane emission from these identified rice fields will be estimated using the IPCC Tier 1 set of equations. First relevant indices (Normalized Differential Moisture Index, Normalized Differential Wetness Index and Rice Growth Vegetation Index) were generated to aid classification of rice fields using LANDSAT data from the USGS. Next the LANDSAT datasets were analyzed for land use change cultivated to rice from 1990 to 2014 to generate rice field maps. ERDAS Imagine, ARCGIS and ENVI tools were used to meet these spatial needs. Methane emissions from this region will be

  5. Young volcanoes in the Chilean Southern Volcanic Zone: A statistical approach to eruption prediction based on time series

    Science.gov (United States)

    Dzierma, Y.; Wehrmann, H.

    2010-03-01

    Forecasting volcanic activity has long been an aim of applied volcanology with regard to mitigating consequences of volcanic eruptions. Effective disaster management requires both information on expected physical eruption behaviour such as types and magnitudes of eruptions as typical for the individual volcano, usually reconstructed from deposits of past eruptions, and the likelihood that a new eruption will occur within a given time. Here we apply a statistical procedure to provide a probability estimate for future eruptions based on eruption time series, and discuss the limitations of this approach. The statistical investigation encompasses a series of young volcanoes of the Chilean Southern Volcanic Zone. Most of the volcanoes considered have been active in historical times, in addition to several volcanoes with a longer eruption record from Late-Pleistocene to Holocene. Furthermore, eruption rates of neighbouring volcanoes are compared with the aim to reveal possible regional relations, potentially resulting from local to medium-scale tectonic dynamics. One special focus is directed to the two currently most active volcanoes of South America, Llaima and Villarrica, whose eruption records comprise about 50 historical eruptions over the past centuries. These two front volcanoes are considered together with Lanín Volcano, situated in the back-arc of Villarrica, for which the analysis is based on eight eruptions in the past 10 ka. For Llaima and Villarrica, affirmed tests for independence of the repose times between successive eruptions permit to assume Poisson processes; which is hampered for Lanín because of the more limited availability of documented eruptions. The assumption of stationarity reaches varying degrees of confidence depending on the time interval considered, ameliorating towards the more recent and hence probably more complete eruption record. With these pre-requisites of the time series, several distribution functions are fit and the goodness of

  6. Crustal structure and fluid distribution beneath the southern part of the Hidaka collision zone revealed by 3-D electrical resistivity modeling

    Science.gov (United States)

    Ichihara, Hiroshi; Mogi, Toru; Tanimoto, Kengo; Yamaya, Yusuke; Hashimoto, Takeshi; Uyeshima, Makoto; Ogawa, Yasuo

    2016-04-01

    The Hidaka collision zone, where the Kurile and northeastern (NE) Japan arcs collide, provides a useful study area for elucidating the processes of arc-continent evolution and inland earthquakes. To produce an image of the collision structure and elucidate the mechanisms of anomalously deep inland earthquakes such as the 1970 Hidaka earthquake (M6.7), we conducted magnetotelluric observations and generated a three-dimensional resistivity distribution in the southern part of the Hidaka collision zone. The modeled resistivity was characterized by a high resistivity area in the upper crust of the Kurile arc corresponding to metamorphic rocks. The model also showed conductive zones beneath the center of the collision zone. The boundary between the resistive and conductive areas corresponds geometrically to the Hidaka main thrust, which is regarded as the arc-arc boundary. The correspondence supports the collision model that the upper-middle part of crust in the Kurile arc is obducting over the NE Japan arc. The conductive areas were interpreted as fluid-filled zones associated with collision processes and upwelling of dehydrated fluid from the subducting Pacific slab. The fluid flow possibly contributes to over-pressurized conduction that produces deep inland earthquakes. We also observed a significant conductive anomaly beneath the area of Horoman peridotite, which may be related to the uplift of mantle materials to the surface.

  7. Major shear zones of southern Brazil and Uruguay: escape tectonics in the eastern border of Rio de La plata and Paranapanema cratons during the Western Gondwana amalgamation

    Science.gov (United States)

    Passarelli, C. R.; Basei, M. A. S.; Wemmer, K.; Siga, O.; Oyhantçabal, P.

    2011-04-01

    The Mantiqueira Province represents a series of supracrustal segments of the South-American counterpart formed during the Gondwana Supercontinent agglutination. In this crustal domain, the process of escape tectonics played a conspicuous role, generating important NE-N-S-trending lineaments. The oblique component of the motions of the colliding tectonic blocks defined the transpressional character of the main suture zones: Lancinha-Itariri, Cubatão-Arcádia-Areal, Serrinha-Rio Palmital in the Ribeira Belt and Sierra Ballena-Major Gercino in the Dom Feliciano Belt. The process as a whole lasted for ca. 60 Ma, since the initial collision phase until the lateral escape phase predominantly marked by dextral and subordinate sinistral transpressional shear zones. In the Dom Feliciano Belt, southern Brazil and Uruguay, transpressional event at 630-600 Ma is recognized and in the Ribeira Belt, despite less coevally, the transpressional event occurred between 590 and 560 Ma in its northern-central portion and between ca. 625 and 595 Ma in its central-southern portion. The kinematics of several shear zones with simultaneous movement in opposite directions at their terminations is explained by the sinuosity of these lineaments in relation to a predominantly continuous westward compression.

  8. Development of the steppe zone in southern Russia based on the reconstruction from the loess-soil formation in the Don-Azov Region

    Science.gov (United States)

    Velichko, A.; Morozova, T. D.; Borisova, O. K.; Timireva, S. N.; Semenov, V. V.; Kononov, Yu. M.; Titov, V. V.; Tesakov, A. S.; Konstantinov, E..; Kurbanov, R. N.

    2012-08-01

    Herbaceous communities in forest ecosystems on the southern part of the Russian Plain appeared in the Middle Miocene (˜10 Ma BP). In the Late Miocene (˜7 Ma BP), feather-grass steppe associations appeared among them. In the time span of 2.7 to 2.1 Ma BP (i.e., in the Early Quaternary, according to the current chronostratigraphic scale), the steppe zone arose on the southern Russian Plain in the Don-Azov Region. Seven stages of this zone development here have been distinguished throughout the Quaternary. The first one (Eopleistocene-Early Pleistocene) was characterized by savanna-like subtropic ecosystems. Then, in the Middle Pleistocene, the temperate zone ecosystems (tallgrass prairie-like steppes) developed here and were followed by steppe ecosystems close to the modern ones in Central Europe. The ecosystems of rich-species forb steppes developed in the Late Pleistocene. Finally, in the optimum of the modern interglacial (Holocene), steppes became similar to the modern ones here, but with a slightly higher precipitation. The general trend is characterized by reduction in heat and water provision and increase in aridization progressing from earlier to later stages.

  9. Plume-proximal mid-ocean ridge origin of Zhongba mafic rocks in the western Yarlung Zangbo Suture Zone, Southern Tibet

    Science.gov (United States)

    He, Juan; Li, Yalin; Wang, Chengshan; Dilek, Yildirim; Wei, Yushuai; Chen, Xi; Hou, Yunling; Zhou, Aorigele

    2016-05-01

    The >2000 km-long Yarlung Zangbo Suture Zone (YZSZ) in southern Tibet includes the remnants of the Mesozoic Neotethyan oceanic lithosphere, and is divided by the Zhada-Zhongba microcontinent into northern and southern branches in its western segment. Zircon U-Pb dating of a doleritic rock from the northern branch has revealed a concordant age of 160.5 ± 1.3 Ma. All of the doleritic samples from the northern branch and the pillow basalt and gabbro samples from the southern branch display consistent REE and trace element patterns similar to those of modern OIB-type rocks. The geochemical and Sr-Nd-Pb isotopic signatures of these OIB-type rocks from the western segment are identical with those of OIB-type and alkaline rocks from other ophiolite massifs along the central and eastern segments of the YZSZ, suggesting a common mantle plume source for their melt evolution. The enriched Sr-Nd-Pb isotopic character of the gabbroic dike rocks from the southern branch points to a mantle plume source, contaminated by subducted oceanic crust or pelagic sediments. We infer that the mafic rock associations exposed along the YZSZ represent the remnants of a Neotethyan oceanic lithosphere, which was developed as part of a plume-proximal seafloor-spreading system, reminiscent of the seamount chains along-across the modern mid-ocean ridges in the Pacific Ocean.

  10. Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in Southern Africa

    OpenAIRE

    Chiara Barbieri; Mário Vicente; Sandra Oliveira; Koen Bostoen; Jorge Rocha; Mark Stoneking; Brigitte Pakendorf

    2014-01-01

    Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speak...

  11. Factors affecting nest survival of Henslow's Sparrows (Ammodramus henslowii) in southern Indiana

    Science.gov (United States)

    Crimmins, Shawn M.; McKann, Patrick C.; Robb, Joseph R.; Lewis, Jason P.; Vanosdol, Teresa; Walker, Benjamin A.; Williams, Perry J.; Thogmartin, Wayne E.

    2016-01-01

    Populations of Henslow’s Sparrows have declined dramatically in recent decades, coinciding with widespread loss of native grassland habitat. Prescribed burning is a primary tool for maintaining grassland patches, but its effects on nest survival of Henslow’s Sparrows remains largely unknown, especially in conjunction with other factors. We monitored 135 nests of Henslow’s Sparrows at Big Oaks National Wildlife Refuge in southern Indiana from 1998–2001 in an effort to understand factors influencing nest survival, including prescribed burning of habitat. We used a mixed-effects implementation of the logistic exposure model to predict daily nest survival in an information theoretic framework. We found that daily survival declined near the onset of hatching and increased with the height of standing dead vegetation, although this relationship was weak. We found only nominal support to suggest that time since burn influenced nest survival. Overall, nest age was the most important factor in estimating daily nest survival rates. Our daily survival estimate from our marginal model (0.937) was similar to that derived from the Mayfield method (0.944) suggesting that our results are comparable to previous studies using the Mayfield approach. Our results indicate that frequent burning to limit woody encroachment into grassland habitats might benefit Henslow’s Sparrow, but that a variety of factors ultimately influence daily nest survival. However, we note that burning too frequently can also limit occupancy by Henslow’s Sparrows. We suggest that additional research is needed to determine the population-level consequences of habitat alteration and if other extrinsic factors influence demographics of Henslow’s Sparrows.

  12. A Magnitude 7.1 Earthquake in the Tacoma Fault Zone-A Plausible Scenario for the Southern Puget Sound Region, Washington

    Science.gov (United States)

    Gomberg, Joan; Sherrod, Brian; Weaver, Craig; Frankel, Art

    2010-01-01

    The U.S. Geological Survey and cooperating scientists have recently assessed the effects of a magnitude 7.1 earthquake on the Tacoma Fault Zone in Pierce County, Washington. A quake of comparable magnitude struck the southern Puget Sound region about 1,100 years ago, and similar earthquakes are almost certain to occur in the future. The region is now home to hundreds of thousands of people, who would be at risk from the shaking, liquefaction, landsliding, and tsunamis caused by such an earthquake. The modeled effects of this scenario earthquake will help emergency planners and residents of the region prepare for future quakes.

  13. Natural and anthropogenic phenomena affecting the historical landslide trend in the Subappennino Dauno (southern Italy)

    Science.gov (United States)

    Lonigro, Teresa; Santaloia, Francesca; Polemio, Maurizio

    2014-05-01

    The aim of this work is to present a methodology, based both on the use methods of time series analyses and of geospatial analyses of monthly climatic data (rainfall, wet days, rainfall intensity, and temperature), annual maximum of short-duration rainfall (from 1 hour to 5 days), historical modification of land use, and population variations in order to characterise the effects of these variables on the occurrence of landsliding in Daunia area, located on the eastern margin of the Southern Apennines thrust belt (southern Italy). Rock strata (mainly) interbedded with clayey marls, clays and silty-clays outcrop in this area. Due to the intense strain history, these successions are found to be from stratified to deeply fractured, up to be disrupted and floating as blocks in a clayey matrix. In turn, the clay units are laminated to intensely fissured and characterised by very poor mechanical properties (Santaloia et al., 2012). The statistical analyses deal with data coming from published databases, integrated by public and private documents, referring to a wide time span. Climate data records from 1877 to 2008 were elaborated, in particular the data coming from sixteen rainfall gauges, ten of which were also thermometric. Moreover, some monthly indices of rainfall, wet days, rainfall intensity, temperature, and landslide occurrence were introduced to simplify the analysis of parameters, characterised by spatial and temporal variability. The population records are from the 19th century up to now while the time period of reference for the land use data is from 1930 up to now. As concerns the landslide events, they were collected from 1918 to 2006. The main source of these records is the AVI database, an existing Italian database that collects data about damaging floods and landslides from 1918 to 1996. This dataset was integrated up to 2006 by consulting newspapers, scientific publications, technical reports, written by the researchers of the CNR-IRPI for the Civil

  14. Fatigue Crack Growth Rate and Fracture Resistance of Heat Affected Zone of Stainless Steel Narrow Gap Welds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jung; Kim, Min U; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of); Cho, Sun Young [Korea Laboratory Engineering System, Daejeon (Korea, Republic of); Yang, Jun Seog [KEPCO, Daejeon (Korea, Republic of)

    2011-05-15

    In nuclear power plants, the automated narrow gap welding (NGW) technique has been widely used in joining stainless steel pipes in primary coolant system. As the primary system pipes are subjected to various transients during plant operation, cracks could initiate and propagate that would cause accidents. To prevent the cracking from developing into sudden failure in the primary system, leak-before-break (LBB) design concept has been developed and applied to many nuclear power plants. Meanwhile, to apply the LBB design, mechanical properties of the structural materials of piping systems should be evaluated, especially at weld zone and heat affected zone (HAZ), because mechanical properties within those regions show considerable scatter and spatial differences. In this study, fatigue crack grow rate (FCGR) and fracture resistance of base metal, weld zone, and HAZ of type 316L stainless steel narrow gap welds were performed at plant operating temperature (315 .deg. C) and room temperature. In particular, FCGR and fracture resistance of HAZ were evaluated in detail and compared to those of base metal

  15. Mechanisms affecting recovery in an upwelling food web: The case of the southern Humboldt

    Science.gov (United States)

    Neira, Sergio; Moloney, Coleen L.; Cury, Philippe; Mullon, Christian; Christensen, Villy

    2009-12-01

    Although bottom-up forcing and overfishing are known to induce shifts in ecosystem states, system changes and their reversibility under each factor are still poorly understood. In this paper, dynamic food web simulations are conducted to evaluate when and why ecological thresholds may be exceeded, and whether bottom-up forcing or fishing is more likely to induce irreversible ecosystem states. Simulations are conducted using a calibrated food web model of the upwelling system off central Chile (33-39°S) and the Ecopath with Ecosim software version 5.1. The effects of fishing scenarios are explored by changing fishing mortality according to trophic level. The effects of bottom-up forcing scenarios are explored by changing phytoplankton biomass, as a function of sea temperature, at El Niño Southern Oscillation (ENSO) and decadal scales. Simulations are carried out for 150 years and impacts, system recovery and regime shifts from each scenario are evaluated using trophodynamic indicators and limit reference points for biomass of functional groups as proxies of food web state and ecological thresholds, respectively. Proportionally distributed fishing along trophic levels is the least harmful fishing scenario, resulting in biomass limit reference points rarely being exceeded and high system recovery. Concentrating fishing at higher and lower trophic levels more likely causes reference points to be exceeded and induces ecosystem changes with low-to-medium recovery potential. No limit reference points are exceeded (or regime shift induced) under ENSO-scale bottom-up forcing. Decadal scale bottom-up forcing has different effects on the system depending on the sequence in which the high and low phytoplankton biomass periods are simulated. A shift from low phytoplankton biomass towards high phytoplankton biomass does not result in biomass limit reference points being exceeded, whereas the opposite sequence results in a large number of limit reference points being exceeded

  16. Continental Collision Zones are Primary Sites of net Continental Crustal Growth: Evidence From the Linzizong Volcanic Succession in Southern Tibet

    Science.gov (United States)

    Niu, Y.; Mo, X.; Dong, G.; Zhao, Z.; Hou, Z.; Zhou, S.; Ke, S.

    2007-12-01

    The Linzizong volcanics (ca. 65-45Ma) and the coeval batholiths (ca. 60-40Ma) of andesitic-to-rhyolitic composition are magmatic response to the India-Asia continental collision that began at ca. 70-65Ma and ended at ca. 45-40Ma with convergence continuing to present [1,2]. These syncollisional magmatic rocks are widely distributed along much of the >1500km long Gangdese Belt immediately north of the India-Asia suture (Yarlung-Zangbo) in southern Tibet [2-6]. Our study of the Linzizong volcanics from the Linzhou Basin (near Lhasa) encourages the proposal that syncollisional granitoid magmatism may in fact account for much of the net contribution to continental crust growth. The Linzizong volcanics in the Linzhou Basin show a first-order temporal change from the lower andesitic formation (64.4-60.6Ma), to the middle dacitic formation (ca. 54Ma), and to the upper rhyolitic formation (48.7-43.9Ma). The three formations show no systematic but overlapping Nd-Sr isotope variations. The isotopically depleted samples with ɛNd(t)>0 (up to + 8) indicate that their primary sources are of mantle origin. The best source candidate in the broad context of Tethyan ocean closing and India- Asia collision is the remaining part of the Tethyan ocean crust [6]. This ocean crust melts when reaching its hydrous solidus during and soon after the collision in the amphibolite facies, producing andesitic melts parental to the Linzizong volcanics (also the coeval batholiths) with inherited mantle isotopic signatures [6]. Ilmenite is abundant in amphibolite [7], and partial melting of amphibolite with ilmenite as a residual phase accounts for the depletion of Nb, Ta and Ti in the melt. The effect of ocean crust alteration plus involvement of mature crustal materials (e.g., recycled terrigeneous sediments) enhances the elevated abundances of Ba, Rb, Th, U, K and Pb in the melt [8,9]. These give the syncolissional Linzizong volcanics characteristic "arc-like" geochemical signature. Residual

  17. Multiobjective optimization of GMAW process of the AA 6063-t5 alloy based on penetration and heat affected zone

    International Nuclear Information System (INIS)

    The selection of technological parameters in a welding process must be led to the optimized results of the operation. Penetration is one of the most decisive factors for the success of the joint. Another important factor is the Heat Affected Zone (HAZ), when the mechanical properties of this one are modified respecting to the base material. The way in which the technological variables of the process affects to both them, penetration and HAZ, are inverse in each case. This work presents an optimization methodology based on the Design of Experiments (DOE) and the Response Surface Method (RSM) of the GMAW process applied to the aluminum alloy AA 6063-T5. This research is focused to obtain penetration rates that make HAZ values to be suitable in current applications. Welding rate has been found to be the most significant technological parameter for controlling the process. (Author)

  18. Cattle-rangeland management practices and perceptions of pastoralists towards rangeland degradation in the Borana zone of southern Ethiopia.

    Science.gov (United States)

    Solomon, T B; Snyman, H A; Smit, G N

    2007-03-01

    A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on traditional burning practices and recurrent droughts were seen as aggravating factors to this

  19. Enhancement of Heat-Affected Zone Toughness of a Low Carbon Steel by TiN Particle

    Science.gov (United States)

    Zhang, Yu; Li, Xiaobao; Ma, Han

    2016-08-01

    Enhancement of heat-affected zone toughness of a weight percentage of 0.014 pct Ti-bearing low carbon steel by TiN particle was investigated. An increase in nitrogen weight percentage from 0.0031 to 0.0083 pct results in increasing of number density of TiN precipitates from 4 × 103 to 3 × 105/mm2, and reduces prior austenite grain size from 850 to 350 μm with a soaking of 1673 K (1400 °C) for 2000 seconds. Effective refinement of austenite grain prohibits formation of ferrite side plate and/or upper bainite, and densely distributed TiN particles promote intra-granular ferrite formation, which is accompanied by an increase of 40 K to 60 K (40 °C to 60 °C) in austenite decomposition temperature during continuous cooling process. The changes in transformed products improved impact toughness of heat-affected zone efficiently, ex., increase absorbed energy of less than 42 J to more than 320 J with a simulated t 8/5 of 550 seconds.

  20. Enhancement of Heat-Affected Zone Toughness of a Low Carbon Steel by TiN Particle

    Science.gov (United States)

    Zhang, Yu; Li, Xiaobao; Ma, Han

    2015-11-01

    Enhancement of heat-affected zone toughness of a weight percentage of 0.014 pct Ti-bearing low carbon steel by TiN particle was investigated. An increase in nitrogen weight percentage from 0.0031 to 0.0083 pct results in increasing of number density of TiN precipitates from 4 × 103 to 3 × 105/mm2, and reduces prior austenite grain size from 850 to 350 μm with a soaking of 1673 K (1400 °C) for 2000 seconds. Effective refinement of austenite grain prohibits formation of ferrite side plate and/or upper bainite, and densely distributed TiN particles promote intra-granular ferrite formation, which is accompanied by an increase of 40 K to 60 K (40 °C to 60 °C) in austenite decomposition temperature during continuous cooling process. The changes in transformed products improved impact toughness of heat-affected zone efficiently, ex., increase absorbed energy of less than 42 J to more than 320 J with a simulated t 8/5 of 550 seconds.

  1. Foreclosure and Health in Southern Europe: Results from the Platform for People Affected by Mortgages.

    Science.gov (United States)

    Vásquez-Vera, Hugo; Rodríguez-Sanz, Maica; Palència, Laia; Borrell, Carme

    2016-04-01

    Housing instability has been shown to be related to poorer health outcomes in various studies, mainly in the USA and UK. Affected individuals are more prone to psychiatric (e.g., major depression, anxiety) and physical disorders (e.g., hypertension). This situation has deteriorated with the onset of the economic crisis. One of the most affected countries is Spain, which has high rates of foreclosure and eviction that continue to rise. In response, a civil movement, The Platform for People Affected by Mortgages (PAH), works to provide solutions to its members affected by foreclosure and advocates for the right to decent housing. The aims of this study ware to describe and compare the health status of PAH members from Catalonia to a sample of the general population and to analyze the association between health status and mortgage status, foreclosure stage, and other socioeconomic variables, among members of the PAH. We conducted a cross-sectional study using a self-administered online questionnaire (2014) administered to 905 PAH members in Catalonia (>18 years; 559 women and 346 men). Results were compared with health indicators from The Health Survey of Catalonia 2013 (n = 4830). The dependent variables were poor mental health (GHQ 12 ≥ 3), and poor self-reported health (fair or poor). All analyses were stratified by sex. We computed age-standardized prevalence and prevalence ratios of poor mental and self-reported health in both samples. We also analyzed health outcomes among PAH members according to mortgage status (mortgage holders or guarantors), stage of foreclosure, and other socioeconomic variables by computing prevalence ratios from robust Poisson regression models. The prevalence of poor mental health among PAH members was 90.6 % in women and 84.4 % in men, and 15.5 and 10.2 % in the general population, respectively. The prevalence of poor self-reported health was 55.6 % in women and 39.4 % in men from the PAH, and 19.2 and 16.1 % in the general

  2. Mercury concentration in the sediments as a function of changing climate in coastal zone of Southern Baltic Sea – preliminary results

    Directory of Open Access Journals (Sweden)

    Bełdowska M.

    2013-04-01

    Full Text Available Mercury, despite of its many uses in industry, is also highly toxic. It is highly neurotoxic, and because of the ability of mercury to penetrate placental barrier, in some countries ban on predatory fish consumption (the main route of mercury into human organism by pregnant women was introduced. There are very little publications describing the consequences of weather anomalies on contaminants cycles. No research was published concerning the reemission of Hg due to climate change in the Southern Baltic Sea. The study area was situated in the coastal zone of the Gulf of Gdansk - the Southern Baltic. Samples of different species of macrophytobenthos were collected once a month during 2006-2012. Samples of Potamogeton pectinatus, sediments and pore waters were collected once a month from February 2011 to January 2012. The climate changes in the moderate latitudes: extension of the fall season, has contributed to stabilization of high concentrations of mercury in pore waters. Lack of ice cover in the coastal zone and simultaneous occurrence of storms had an impact on supply of the organic matter to the sediments and the increased concentration of Hg. More intense burning of fossil fuels in this season favored the increased metal concentration in the atmosphere and consequently an increase of the atmospheric deposition of metals to the sediments. This led to a fourfold increase of the mercury concentration in sediments as compared to fall season.

  3. Health in the hot zone - How could global warming affect humans?

    Energy Technology Data Exchange (ETDEWEB)

    Monastersky, R.

    1996-04-06

    A soon-to-be-released report from the World Health Organization examines the health effects of global warming, calling climate change one of the largest public health challenges for the upcoming century. The issue extends beyond tropical illness: deaths caused directly by heat, dwindling agricultural yields etc. could all affect human health. This article looks at the following health related effects and gives an overview of the scientific information available on each: temperature and mortality; tropical trouble, including vecorborne diseases and increase in susceptable populations; and waterborne problems such as cholera, harmful algal bloomes, food shortages.

  4. Regional structure of the southern segment of Central Iberian Zone (Spanish Variscan Belt) interpreted from potential field images and 2.5 D modelling of Alcudia gravity transect

    Science.gov (United States)

    García-Lobón, J. L.; Rey-Moral, C.; Ayala, C.; Martín-Parra, L. M.; Matas, J.; Reguera, M. I.

    2014-02-01

    This study presents a structural interpretation of potential field data at the southern segment of the Spanish Central Iberian Zone, where little is known about its geometry and physical properties in depth. We used ground gravity and aeromagnetic data from the Spanish Geological Survey (IGME) databases, together with a gravity survey recently acquired along the Alcudia deep seismic reflection profile, and also petrophysical data from rock samples, in part specifically acquired for this work. The aim is to characterize with potential fields the depth structure and physical properties of a complex area, focusing on features of the upper crust where the potential fields can provide a useful insight, as these features appear to be transparent in the images of seismic surveys carried up to date. After building a 2.5 D model of the magnetic susceptibility and density distribution for the whole crust with the constraints of the Alcudia seismic transect, relationships between lower and upper crustal structures can be better established, and surface geophysical maps allow estimating the lateral extensions of the main structures characterized by the potential field modelling. Interpreted gravity and magnetic Alcudia features consist of: 1) long-wavelength anomalies due to changes in crustal thickness and structure, identified along the Alcudia seismic reflection profile; some crustal boundaries and the seismic Moho have been slightly modified in the potential field model to fit the observed data; and, 2) short wavelength anomalies related to upper crustal features as large NW-SE faults and folds, and plutonic alignments. Northern and southern Alcudia segments show relevant lower-middle crust shortening structures underneath extensive Variscan plutons (Mora, Pedroches) and folded basins (Pedroches). Potential field imaging and modelling of these structures have provided a better understanding of the subsurface geology, particularly in non-reflective areas, unravelling the

  5. Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru)

    NARCIS (Netherlands)

    Louterbach, M.; Roddaz, M.; Bailleul, J.; Antoine, P.O.; Adnet, S.; Kim, J.H.; van Soelen, E.E.; Parra, F.; Gérard, J.; Calderon, Y.; Gagnaison, C.; Sinninghe Damsté, J.S.; Baby, P.

    2014-01-01

    This article presents new biostratigraphic dating, facies analysis, organic geochemical data and Nd–Sr isotopic provenance from five outcrops of southern Amazonia (MD-85, MD-177 MD-184, MD-255 and MD-256) to document for the first time the presence of a shallow marine ingression in the Paleocene of

  6. Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru)

    NARCIS (Netherlands)

    Louterbach, M.; Roddaz, M.; Bailleul, J.; Antoine, P. O.; Adnet, S.; Kim, J. H.; van Soelen, E.; Parra, F.; Gérard, J.; Calderon, Y.; Gagnaison, C.; Sinninghe Damsté, J.S.; Baby, P.

    2014-01-01

    This article presents new biostratigraphic dating, facies analysis, organic geochemical data and Nd-Sr isotopic provenance from five outcrops of southern Amazonia (MD-85, MD-177 MD-184, MD-255 and MD-256) to document for the first time the presence of a shallow marine ingression in the Paleocene of

  7. Microbiological and physicochemical factors affecting Aspergillus section Flavi incidence in Cavendish banana (Musa cavendishii) chips production in Southern Philippines.

    Science.gov (United States)

    Sales, A C; Azanza, P V; Yoshizawa, T

    2005-01-01

    Microbiological and physicochemical factors affecting the incidence of Aspergillus section Flavi in dried Cavendish banana (Musa cavendishii) chips production in Southern Philippines were examined. The average counts of Aspergillus section Flavi (AFC) in fresh and dried Cavendish bananas from 10 production batches of the Philippine Agro-Industrial Development Cooperative in Davao del Norte, Southern Philippines were 1.2 x 10(2) and 1.6 x 10(2) cfu/g, respectively. Isolates from both samples were identified to be Aspergillus flavus based on spore type and conidial structure of isolates. An increasing trend in the AFC of Cavendish bananas was observed during dried banana chips processing. Variability in the AFC between production batches was attributed to differences in aerobic and fungal populations and physicochemical characteristics of the fruits, peel damage of the raw materials, concentration of AFC in the air and food-contact surfaces of the production area, and temperature and relative humidity (RH) conditions of the environment during production and storage. Physicochemical characteristics of Cavendish bananas from the receipt of raw materials up to the first day of drying were within the reported range of values allowing growth and toxin production by aflatoxigenic fungi. Air-borne AFC varied depending on the section of the production area examined. The close proximity of the waste disposal area from the production operation to the preparation, drying and storage areas suggests that cross-contamination, probably air-borne or insect-borne was a likely occurrence. The hands of workers were also identified as AFC sources. Results of this study highlight the need for the development of strategies to control aflatoxigenic fungi and aflatoxin contamination in Philippine dried Cavendish bananas.

  8. Ichthyoplankton in a southern african surf zone: Nursery area for the postlarvae of estuarine associated fish species?

    Science.gov (United States)

    Whitfield, A. K.

    1989-12-01

    The surf zone ichthyoplankton of Swartvlei Bay was studied between February 1986 and June 1987, with particular emphasis on its potential role as a nursery area for estuarine associated marine fish species. Larvae and/or postlarvae of 16 families were identified from the surf zone, with the Gobiidae, Soleidae, Sparidae and Mugilidae comprising 85·7% of all teleosts sampled. The postlarvae of several taxa (including the six most common species), which utilize the Swartvlei estuary as a juvenile nursery area, were abundant in the surf zone. Conversely, species which are common in nearshore marine waters as juveniles and adults, but seldom enter estuaries, totalled less than 8% of the surf zone ichthyoplankton assemblage. Larval and postlarval densities peaked during summer when water temperatures exceeded 19°C and the estuary mouth was open. Concentrations of ichthyoplankton were highest at those sampling stations closest to the estuary mouth during the summer period. Diel changes in total catches revealed no significant difference between day and night densities; but of the four major taxa, the Mugilidae and Sparidae tended to be more abundant during the day, the Gobiidae at night and the Soleidae showed no distinct pattern. Results from a 24 h sampling session indicated that tidal phase may also be important in governing ichthyoplankton abundance in the surf zone.

  9. Land-use and soil depth affect resource and microbial stoichiometry in a tropical mountain rainforest region of southern Ecuador.

    Science.gov (United States)

    Tischer, Alexander; Potthast, Karin; Hamer, Ute

    2014-05-01

    Global change phenomena, such as forest disturbance and land-use change, significantly affect elemental balances as well as the structure and function of terrestrial ecosystems. However, the importance of shifts in soil nutrient stoichiometry for the regulation of belowground biota and soil food webs have not been intensively studied for tropical ecosystems. In the present account, we examine the effects of land-use change and soil depth on soil and microbial stoichiometry along a land-use sequence (natural forest, pastures of different ages, secondary succession) in the tropical mountain rainforest region of southern Ecuador. Furthermore, we analyzed (PLFA-method) whether shifts in the microbial community structure were related to alterations in soil and microbial stoichiometry. Soil and microbial stoichiometry were affected by both land-use change and soil depth. After forest disturbance, significant decreases of soil C:N:P ratios at the pastures were followed by increases during secondary succession. Microbial C:N ratios varied slightly in response to land-use change, whereas no fixed microbial C:P and N:P ratios were observed. Shifts in microbial community composition were associated with soil and microbial stoichiometry. Strong positive relationships between PLFA-markers 18:2n6,9c (saprotrophic fungi) and 20:4 (animals) and negative associations between 20:4 and microbial N:P point to land-use change affecting the structure of soil food webs. Significant deviations from global soil and microbial C:N:P ratios indicated a major force of land-use change to alter stoichiometric relationships and to structure biological systems. Our results support the idea that soil biotic communities are stoichiometrically flexible in order to adapt to alterations in resource stoichiometry.

  10. Atmospheric Deposition of Heavy Metals in Soil Affected by Different Soil Uses of Southern Spain

    Science.gov (United States)

    Acosta, J. A.; Faz, A.; Martínez-Martínez, S.; Bech, J.

    2009-04-01

    Heavy metals are a natural constituent of rocks, sediments and soils. However, the heavy metal content of top soils is also dependent on other sources than weathering of the indigenous minerals; input from atmospheric deposition seems to be an important pathway. Atmospheric deposition is defined as the process by which atmospheric pollutants are transferred to terrestrial and aquatic surfaces and is commonly classified as either dry or wet. The interest in atmospheric deposition has increased over the past decade due to concerns about the effects of deposited materials on the environment. Dry deposition provides a significant mechanism for the removal of particles from the atmosphere and is an important pathway for the loading of heavy metals into the soil ecosystem. Within the last decade, an intensive effort has been made to determine the atmospheric heavy metal deposition in both urban and rural areas. The main objective of this study was to identification of atmospheric heavy metals deposition in soil affected by different soil uses. Study area is located in Murcia Province (southeast of Spain), in the surroundings of Murcia City. The climate is typically semiarid Mediterranean with an annual average temperature of 18°C and precipitation of 350 mm. In order to determine heavy metals atmospheric deposition a sampling at different depths (0-1 cm, 1-5 cm, 5-15 cm and 15-30 cm) was carried out in 7 sites including agricultural soils, two industrial areas and natural sites. The samples were taken to the laboratory where, dried, passed through a 2 mm sieve, and grinded. For the determination of the moisture the samples were weighed and oven dried at 105 °C for 24 h. The total amounts of metals (Pb, Cu, Pb, Zn, Cd, Mn, Ni and Cr) were determined by digesting the samples with nitric/perchoric acids and measuring with ICP-MS. Results showed that zinc contamination in some samples of industrial areas was detected, even this contamination reaches 30 cm depth; thus it is

  11. Linking river, floodplain, and vadose zone hydrology to improve restoration of a coastal river affected by saltwater intrusion.

    Science.gov (United States)

    Kaplan, D; Muñoz-Carpena, R; Wan, Y; Hedgepeth, M; Zheng, F; Roberts, R; Rossmanith, R

    2010-01-01

    Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of damaged ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems affected by saltwater intrusion but are difficult to monitor and often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress [Taxodium distichum (L.) Rich.] floodplain swamps in southeast Florida. We investigated soil moisture and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 min were installed along two transects-one in an upstream, freshwater location and one in a downstream tidal area. Complemented by surface water, groundwater, and meteorological data, these unique 4-yr datasets quantified the spatial variability and temporal dynamics of vadose zone hydrology. Results showed that soil moisture can be closely predicted based on river stage and topographic elevation (overall Nash-Sutcliffe coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds (0.3125 S m(-1)) for bald cypress upstream but did so in some downstream areas. This provided an explanation for observed vegetation changes that both surface water and groundwater salinity failed to explain. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on vadose zone hydrology and provide relationships for evaluating proposed restoration and management scenarios for the Loxahatchee River. PMID:21043263

  12. Peridotites from a ductile shear zone within back-arc lithospheric mantle, southern Mariana Trench: Results of a Shinkai 6500 dive

    Science.gov (United States)

    Michibayashi, K.; Ohara, Y.; Stern, R. J.; Fryer, P.; Kimura, J.-I.; Tasaka, M.; Harigane, Y.; Ishii, T.

    2009-05-01

    Two N-S fault zones in the southern Mariana fore arc record at least 20 km of left-lateral displacement. We examined the eastward facing slope of one of the fault zones (the West Santa Rosa Bank fault) from 6469 to 5957 m water depth using the submersible Shinkai 6500 (YK06-12 Dive 973) as part of a cruise by the R/V Yokosuka in 2006. The dive recovered residual but still partly fertile lherzolite, residual lherzolite, and dunite; the samples show mylonitic, porphyroclastic, and coarse, moderately deformed secondary textures. Crystal-preferred orientations of olivine within the peridotites show a typical [100](010) pattern, with the fabric intensity decreasing from rocks with coarse secondary texture to mylonites. The sampled peridotites therefore represent a ductile shear zone within the lithospheric mantle of the overriding plate. Peridotites were probably exposed in association with a tear in the subducting slab, previously inferred from bathymetry and seismicity. Furthermore, although the dive site is located in the fore arc close to the Mariana Trench, spinel compositions within the sampled peridotites are comparable to those from the Mariana Trough back arc, suggesting that back-arc basin mantle is exposed along the West Santa Rosa Bank fault.

  13. Fine structure in the inter-critical heat-affected zone of HQ130 super-high strength steel

    Indian Academy of Sciences (India)

    Li Yajiang; Wang Juan; Liu Peng

    2003-02-01

    The microstructure in the inter-critical heat-affected zone (ICHAZ) of HQ130 steel, has been investigated by thermo-simulation test, SEM and TEM. The problem of toughness decrease in the ICHAZ (p = 800°C) as well as the effect of M–A constituent and carbide precipitation on brittleness was analysed. The test results indicated that the microstructure in the ICHAZ of HQ130 steel was mostly a mixture of lath martensite (ML) and granular bainite (Bg) with a fine but nonuniform grain structure. The cause of brittleness in the ICHAZ was related to production of the M–A constituent in the local region and carbide precipitation. By controlling the welding heat input carbide precipitation and the formation of the M–A constituent can be avoided or decreased.

  14. Factors affecting the quality of fish caught by Native Americans in the Zone 6 fishery 1991 through 1993

    Energy Technology Data Exchange (ETDEWEB)

    Abernethy, C.S.

    1994-09-01

    A program to monitor the salmon and steelhead (Oncorhynchus spp.) fishery in the lower Columbia River (Zone 6 fishery) was initiated in 1991 to respond to questions and comments frequently made by Native Americans at public meetings. Native Americans were concerned that the quality of the Columbia River had deteriorated and that the poor environmental conditions had affected the health and quality of fish they relied on for subsistence, ceremonial, religious, and commercial purposes. They also feared that eating contaminated fish might endanger the health of their children and future generations. Operations at the Hanford Site were listed as one of many causes of the deteriorating environment. Fisheries pathologists concluded that most of the external symptoms on fish were related to bacterial infection of gill net abrasions and pre-spawning trauma, and were not caused by pollution or contamination of the Columbia River. The pathologists also stated that consumption of the fish posed no threat to human consumers.

  15. Lipophilic toxin profiles detected in farmed and benthic mussels populations from the most relevant production zones in Southern Chile.

    Science.gov (United States)

    Garcia, Carlos; Rodriguez-Unda, Nelson; Contreras, Cristóbal; Barriga, Andrés; Lagos, Néstor

    2012-01-01

    Lipophilic toxins associated with diarrhoeic toxins were found in Mytilus chilensis (Blue mussels) and Aulacomya ater (Ribbed mussels). These shellfish samples were collected from Chiloe Island, Southern Chile. The samples were tested by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After the analysis, four toxins were found: DTX-1, DTX-3, YTX and PTX. All toxins were identified by comparing their HPLC retention times with those of analytical standards and confirmed by LC-MS/MS. Dinophysistoxin-1 (DTX-1) and dinophysistoxin-3 (DTX-3) toxins were the major components within the mussel extracts. Nevertheless, the percentages of these toxins differed depending on the area they were collected from and/or the sampling date. The levels detected in Butacheuques Island for okadaic acid (OA) was 267 ± 3.5 µg OA eq kg(-1) (p Chile, which is, to date, the more complex mix of lipophilic toxins ever found in mussels samples from Southern Chile. PMID:22424031

  16. Investigation on the crystallography of the transformation products of reverted austenite in intercritically reheated coarse grained heat affected zone

    International Nuclear Information System (INIS)

    Highlights: ► Area of reverted austenite is traced out by crystallographic information. ► Bainite and martensite regions were confirmed within it. ► The martensite region is considered as the blocky MA particles. ► Martensite region has high deformation to initiate fracture. ► More uniform transformation of the reverted austenite is good for toughness. -- Abstract: In present study the intercritically reheated coarse grained heat affected zone (ICCGHAZ) showing the worst impact toughness in the heat affected zone of multi-pass welding was simulated by Gleeble-1500, and its microstructure was investigated in detail by means of scanning electron microscope (SEM) and electron backscattering diffraction (EBSD). With the crystallographic information from EBSD scanning the area of a single reverted austenite grain which formed during the thermal cycles of second pass simulation was traced out. Within it two regions with different characteristic both in morphology and crystallography were found out, showing an un-uniform transformation of the reverted austenite. The region I is a bainitic region containing larger bainitic ferrite grains, while the region II is made up of several clusters containing tiny grains. Based on the crystallographic information each cluster was determined as martensite island thereby should be considered as blocky Martensite/Austenite constituent (M/A), which is hard phase and harmful for toughness. Analysis on the level of deformation shows that the region II is much higher deformed than the region I, indicating there is high stress concentration within the region II. The possible influence of the region I and the region II on fracture is discussed under the early proposed M/A’s fracture-initiating mechanisms. It suggests that the main cause of the toughness reduction is the un-uniform transformation of the reverted austenite, and the toughness performance of the ICCGHAZ could be improved if the transformation of the reverted

  17. Low-dose irradiation effects on creep properties of type 304 stainless steel weld metal, heat-affected zones, and welded joints

    International Nuclear Information System (INIS)

    The integrity of large non-replaceable primary reactor components of liquid metal fast breeders largely depends on the properties of weld metal and heataffected zones. Safety authorities, involved in the licensing of the SNR-300, have required the measurement and interpretation of post-irradiation creep and creep rupture properties of DIN 1.4948 (Type 304) stainless steel weld metal and heat-affected zones. For the present investigation, weld metal in as-deposited and stress-relieved condition has been subjected to tension and creep tests. The heat-affected zone structure was studied with specimens subjected to temperature cycles representative for different locations in the parent metal near the fusion zone. The specimens were irradiated in the HFR Petten at 823 K submerged in sodium to a total neutron fluence of 5 X 103 n/m2. Irradiation has no significant effect on creep and tensile properties of weld metal. The heat-affected zone is strongly affected by low-dose neutron irradiation: its 10000-h creep strength is about 25 MPa lower than that of parent metal under similar conditions. The creep strength of welded joints is controlled by a strain limit criterion. In unirradiated condition, the weld metal has the lowest ductility and rupture occurs in the weld metal. In irradiated condition the heat-affected zone has the lowest ductility for the higher creep stresses (>175 MPa) and lower rupture times (<3000 h). For lower creep stresses, the weld metal, though not affected by irradiation, determines the creep strength. Application of a stress relief treatment reduces the dislocation density and changes the carbide population in weld metal to such a degree that the ductility increases considerably with little loss of strength. The grain coarsening in the heat-affected zones, amplifying the irradiation embrittlement, can be suppressed by using low heat input welding techniques

  18. Affectivity

    OpenAIRE

    Stenner, Paul; Greco, Monica

    2013-01-01

    The concept of affectivity has assumed central importance in much recent scholarship, and many in the social sciences and humanities now talk of an ‘affective turn’. The concept of affectivity at play in this ‘turn’ remains, however, somewhat vague and slippery. Starting with Silvan Tomkins’ influential theory of affect, this paper will explore the relevance of the general assumptions (or ‘utmost abstractions’) that inform thinking about affectivity. The technological and instrumentalist char...

  19. Geophysical surveying of slopes affected by debris flows: the case of S. Felicea Cancello (Caserta, Southern Italy

    Directory of Open Access Journals (Sweden)

    S. Superbo

    2003-06-01

    Full Text Available This paper contains the results of a series of geophysical investigations carried out on the largest debris flow to have taken place in Tavernole, S. Felice a Cancello (Caserta, Southern Italy. The landslide occurred in concurrence with other catastrophic events in the Sarno Mountains in May 1998. This research project is part of a series of geological, geomorphological and geotechnical studies whose purpose is to improve the knowledge of this type of phenomenon. The project also tested and compared various survey methods in the sample area of S. Felice a Cancello. Geophysical surveying allowed us to collect information regarding the physical features and thickness of the materials affected by landslide phenomena and to verify the applicability and effectiveness of the various indirect surveying methods adopted. The preliminary results of the study enabled us to generate a series of suggestions which could prove useful in formulating the correct approach to this type of problem to be adopted in ordinary professional practice. These indications concerned the type of geophysical surveying to be conducted and, where applicable, the means of implementation. In general, seismic refraction was found to be the best technique for collecting information on the area studied.

  20. The Incidence, Severity and Occurrence of Four Viruses Infecting Pepper (Capsicum spp. in the Southern Guinea Savannah Agro-ecological Zone of Nigeria

    Directory of Open Access Journals (Sweden)

    Taiye Hussein Aliyu

    2015-01-01

    Full Text Available The incidence, severity and occurrence of four viruses infecting pepper were determined in Kwara State, Nigeria. A disease survey and antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA were the tools deployed to achieve these objectives. The survey indicated the highest virus incidence (97% in four locations, and the lowest incidence (16% in three locations, with variations in severity scores. Th e ELISA result indicated the occurrence of all four viruses with the highest percentage occurrence of virus in the samples as follows: Pepper veinal mottle virus (36.3%, Blackeye cowpea mosaic virus (16.2%, Cowpea aphid borne mosaic virus (7.4%, and Cucumber mosaic virus in the locations (4.8%. The results indicate the prevalence of these viruses on pepper in the Southern Guinea savannah agroecological zone and therefore the need for constant studies to detect other viruses that limit pepper production.

  1. Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in Southern Africa.

    Directory of Open Access Journals (Sweden)

    Chiara Barbieri

    Full Text Available Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses.

  2. The Two Subduction Zones of the Southern Caribbean: Lithosphere Tearing and Continental Margin Recycling in the East, Flat Slab Subduction and Laramide-Style Uplifts in the West

    Science.gov (United States)

    Levander, A.; Bezada, M. J.; Niu, F.; Schmitz, M.

    2015-12-01

    The southern Caribbean plate boundary is a complex strike-slip fault system bounded by oppositely vergent subduction zones, the Antilles subduction zone in the east, and a currently locked Caribbean-South American subduction zone in the west (Bilham and Mencin, 2013). Finite-frequency teleseismic P-wave tomography images both the Atlanic (ATL) and the Caribbean (CAR) plates subducting steeply in opposite directions to transition zone depths under northern South America. Ps receiver functions show a depressed 660 discontinuity and thickened transition zone associated with each subducting plate. In the east the oceanic (ATL) part of the South American (SA) plate subducts westward beneath the CAR, initiating the El Pilar-San Sebastian strike slip system, a subduction-transform edge propagator (STEP) fault (Govers and Wortel, 2005). The point at which the ATL tears away from SA as it descends into the mantle is evidenced by the Paria cluster seismicity at depths of 60-110 km (Russo et al, 1993). Body wave tomography and lithosphere-asthenosphere boundary (LAB) thickness determined from Sp and Ps receiver functions and Rayleigh waves suggest that the descending ATL also viscously removes the bottom third to half of the SA continental margin lithospheric mantle as it descends. This has left thinned continental lithosphere under northern SA in the wake of the eastward migrating Antilles subduction zone. The thinned lithosphere occupies ~70% of the length of the El Pilar-San Sebastian fault system, from ~64oW to ~69oW, and extends inland several hundred kilometers. In northwestern SA the CAR subducts east-southeast at low angle under northern Colombia and western Venezuela. The subducting CAR is at least 200 km wide, extending from northernmost Colombia as far south as the Bucaramanga nest seismicity. The CAR descends steeply under Lake Maracaibo and the Merida Andes. This flat slab is associated with three Neogene basement cored, Laramide-style uplifts: the Santa Marta

  3. The Influence of Land Subsidence, Quarrying, Drainage, Irrigation and Forest Fire on Groundwater Resources and Biodiversity Along the Southern Po Plain Coastal Zone (Italy)

    Science.gov (United States)

    Antonellini, M. A.; Mollema, P. N.

    2014-12-01

    The coastal zone of the southern Po plain is characterized by low lying land, which is reclaimed to permit settlements and agriculture. The history, tourism resorts and peculiar coastal environments make this territory attractive and valuable. Natural and fluid-extraction-induced land subsidence along with coastal erosion are major problems. Touristic development has strongly modified the landscape; coastal dunes have been in part removed to make room for hotels and quarrying has caused the formation of gravel pit lakes close to the shoreline. Protected natural areas include a belt of coastal dunes, wetlands, and the internal historical forests of San Vitale and Classe. The dunes have largely lost their original vegetation ecosystem, because years ago they have been colonized with pine trees to protect the adjacent farmland from sea spray. These pine forests are currently a fire hazard. Land reclamation drainage keeps the water table artificially low. Results of these anthropogenic disturbances on the hydrology include a decrease in infiltration rates, loss of freshwater surface bodies, encroachment of saltwater inland from the river estuaries, salinization of the aquifer, wetlands and soil with a loss in plant and aquatic species biodiversity. Feedback mechanisms are complex: as land subsidence continues, drainage increases at the same pace promoting sea-water intrusion. The salinity of the groundwater does not allow for plant species richness nor for the survival of large pine trees. Farmland irrigation and fires in the pine forests, on the other hand, allow for increased infiltration and freshening of the aquifer and at the same time promote plant species diversity. Our work shows that the characteristics of the southern Po coastal zone require integrated management of economic activities, natural areas, and resources. This approach is different from the ad hoc measures taken so far, because it requires long term planning and setting a priority of objectives.

  4. Treatment outcome of human immunodeficiency virus and tuberculosis co-infected patients in public hospitals of eastern and southern zone of Tigray region, Ethiopia

    Directory of Open Access Journals (Sweden)

    Mehretu Belayneh

    2015-02-01

    Full Text Available Background:Tuberculosis is a leading cause of death among people living with human immunodeficiency virus. In sub-Saharan Africa, tuberculosis accounts for more than 78% of all deaths among people with human immunodeficiency virus.Objectives:To assess tuberculosis treatment outcome and the associated factors in adult tuberculosis/human immunodeficiency virus co-infected patients in four public hospitals of eastern and southern zone of Tigray region, Ethiopia.Methodology:Institution based cross-sectional study design was used to examine secondary data from tuberculosis/human immunodeficiency virus co-infected patients attending four public hospitals of eastern and southern zone of Tigray, from January 2009 to August 2011. Systematic random sampling technique was used to select individual patient cards from the respective hospitals. Univariate analysis and multivariate logistic regression modeling was used to assess the impact of each variable in predicting treatment outcome.Results:Out of 342 patients included, 199 (58.2% patients completed treatment, 43 (12.6% patients were cured, 88 (25.7% died, 7 (2% defaulted, and 5 (1.5% patients failed treatment. Treatment success rate was around 71%. In the multivariate logistic regression analysis the factors that were strongly associated with unfavorable tuberculosis treatment outcomes were WHO stage IV (AOR = 3.2, CI = 1.58-6.82, p-value = 0.001, age greater than 45 years (AOR = 6.08, CI = 2.28-16.23 and baseline CD4 count less than 200 cells/L (AOR = 6.19, CI = 2.28-16.89, p-value = 0.001.Conclusion:The rate of treatment success in this study was lower than the rate newly recommended by WHO. Therefore, efforts should be undertaken to improve treatment success rates of both diseases.

  5. Feeding strategy of Menticirrhus americanus and Menticirrhus littoralis (Perciformes: Sciaenidae) juveniles in a sandy beach surf zone of southern Brazil

    OpenAIRE

    Fábio L. Rodrigues; João P Vieira

    2010-01-01

    The diet and foraging strategy of juvenile Menticirrhus americanus (Linnaeus, 1758) and Menticirrhus littoralis (Holbrook, 1847) were studied, testing the existence of trophic overlap between these species and within different seasons (spring and summer). Individuals were sampled using a beach seine in the surf zone near Rio Grande, state of Rio Grande do Sul, Brazil. Based on Morisita's Simplified Overlap Index and Bootstrapping technique, trophic overlap between species was considered high ...

  6. Estimation of rainfall inputs and direct recharge to the deep unsaturated zone of Southern Niger using the chloride profile method

    OpenAIRE

    Bromley, J.; Edmunds, W.M.; Fellman, E.; Brouwer, J.; Gaze, S.R.; Sudlow, J.; Taupin, Jean-Denis

    1997-01-01

    An estimate of direct groundwater recharge below a region of natural woodland (tiger bush) has been made in south-west Niger using the solute profile technique. Data has been collected from a 77 m deep well dug within the study area covered by HAPEX-Sahel (Hydrological and Atmospheric Pilot Experiment), an international large-scale energy, water and carbon balance experiment carried out during the summer of 1992. During well construction samples were taken from the unsatured zone at the follo...

  7. Plate boundary forces in the vicinity of Trinidad-the-transition from transpression to transtension in the Southern Caribbean plate boundary zones

    Energy Technology Data Exchange (ETDEWEB)

    Algar, S.T.; Pindell, J.L. (Dartmouth College, Hanover, NH (United States))

    1993-02-01

    Deformation in the southern Caribbean plate boundary zones as recorded in the Northern Range of Trinidad initiated in the Oligocene with northward vergent gravity sliding of Northern Range sediments due to uplift and oversteepening of the previously passive margin by the eastward migration of the Caribbean flexural forebulge. Progressive east-southeast transvergence of the Caribbean Plate with respect to South America overthrust incorporated the Northern Range sediments into the Caribbean accretionary prism, thrusting them south-southeast to produce a Middle Miocene transpressive foreland fold and thrust belt in southern Trinidad. Late Miocene deformation within Trinidad was increasingly dominated by right-lateral strike-slop (RLSS) faulting, at the expense of transpressive compressional features. Right-stepping of RLSS motion initiated the Gulf of Paria and Caroni pull-apart basins, Since Early Pliocene these basins and other areas to the north of Trinidad have undergone north-south extension in addition to east-west trending RLSS. Such extension caused the northward withdrawal of Caribbean terranes from atop of the Northern Range, Resulting in rapid isostatically induced uplift (approximately 0.5 mmyr[sup -1]). This change in deformation style may relate to a hitherto unrecognized shift in the relative motion of the eastern Caribbean Plate with respect to South America: from east-southeast-directed transpression to east-northeast-directed transtension.

  8. Microstructural evolution and mechanical properties of heat affected zones for 9Cr2WVTa steels with different carbon contents

    International Nuclear Information System (INIS)

    Highlights: • The weldability of 9Cr2WVTa steel with different carbon contents was studied. • The HAZs of the 9Cr2WVTa steel include three characteristic regions. • Residual delta-ferrite significantly deteriorates the impact property of HAZs. • The twin martensite deteriorates the impact toughness as a whole. • The 9Cr2WVTa steel with 0.14–0.17 wt.% carbon content has good weldability. - Abstract: The microstructures and mechanical properties of heat affected zones (HAZs) by Gas Tungsten Arc Welding (GTAW) were studied for 9Cr2WVTa steels with carbon content varying from 0.07 wt.% to 0.25 wt.%. Enlarged HAZs samples with 8 mm to 10 mm wide uniform temperature zone were prepared by the thermal–mechanical physical simulator Gleeble 1500 based on the Finite Element Method (FEM) numerical simulation and experimental measurement for the welding thermal cycle process and weld profile. The microstructures were observed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). In addition, the mechanical properties tests including micro-hardness test, tensile test and impact test were carried out to investigate the effects of the carbon content and the welding thermal cycle. The results show that the big blocky delta ferrite in 9Cr2WVTa steel with lower carbon content deteriorates the impact property. On the other hand, the quenched martensite, especially for the twin martensite in 9Cr2WVTa steel with higher carbon content, deteriorates the impact toughness as well. The weldability of 9Cr2WVTa steel can be improved by adjusting the carbon content between 0.14 wt.% and 0.17 wt.%

  9. Modeling of Soil and Tree Water Status Dynamics in a Mixed-Conifer Forest of the Southern Sierra Critical Zone Observatory

    Science.gov (United States)

    Hopmans, J. W.; Rings, J.; Kamai, T.; Mollaei Kandelous, M.; Hartsough, P. C.; Vrugt, J. A.

    2012-12-01

    Trees play a key role in controlling the water and energy balance at the land-air surface. By changing water content of soil and atmosphere, trees influence meteorological, climatological and hydrological cycles. Numerical models allow simulating the relevant hydrological processes; most importantly the movement of water as it is transported through the soil, taken up by roots into the tree and ultimately transpired into the atmosphere along water potential gradients across the soil-root-tree-atmosphere continuum (SPAC). The results of a multi-year deployment of soil moisture sensors to study the hydrologic/biotic interactions in a mixed-conifer forest in the Southern Sierra Critical Zone Observatory (CZO) will be presented. To better understand root-soil water interactions, a mature white fir (Abies concolor) and the surrounding root zone was continuously monitored (sap flow, canopy stem water potential, soil moisture, soil water potential and temperature), to characterize the hydraulics SPAC. In addition, we present a hydrodynamic model, simulating unsaturated flow in the soil and tree with stress functions controlling spatially distributed root uptake and canopy transpiration. To parameterize the in-situ tree water relationships, we combine the numerical model with observational data in an optimization framework, minimizing residuals between modeled and measured observational data.

  10. Fibrous gypsum veins as diffuse features and within fault zones: the case study of the Pisco Basin (Ica desert, southern Peru)

    Science.gov (United States)

    Rustichelli, Andrea; Di Celma, Claudio; Tondi, Emanuele; Baud, Patrick; Vinciguerra, Sergio

    2016-04-01

    New knowledge on patterns of fibrous gypsum veins, their genetic mechanisms, deformation style and weathering are provided by a field- and laboratory-based study carried out on the Neogene to Quaternary Pisco Basin sedimentary strata (porous sandstones, siltstones and diatomites) exposed in the Ica desert, southern Peru. Gypsum veins vary considerably in dimensions, attitudes and timing and can develop in layered and moderately fractured rocks also in the absence of evaporitic layers. Veins occur both as diffuse features, confined to certain stratigraphic levels, and localised within fault zones. Arrays formed by layer-bounded, mutually orthogonal sets of steeply-dipping gypsum veins are reported for the first time. Vein length, height and spacing depend on the thickness of the bed packages in which they are confined. Within fault zones, veins are partly a product of faulting but also inherited layer-bounded features along which faults are superimposed. Due to the different petrophysical properties with respect to the parent rocks and their susceptibility to textural and mineralogical modifications, water dissolution and rupture, gypsum veins may have a significant role in geofluid management. Depending on their patterns and grade of physical and chemical alteration, veins may influence geofluid circulation and storage, acting as barriers to flow and possibly also as conduits.

  11. Origin of the regional stress field along the Liquine-Ofqui Fault Zone (LOFZ), Southern Chilean Andes by means of FE Simulation

    Institute of Scientific and Technical Information of China (English)

    Md. Rafiqul Islam

    2009-01-01

    The Liquine-Ofqui Fault Zone (LOFZ) of southern Chilean Andes is one of the largest active strike-slip fault zones. There is an ongoing debate regarding the origin of the stress field along the LOFZ due to its complex geometry. This paper represents a study of the origins of the LOFZ regional stress field. Stress fields are calculated by finite element (FE) analysis. The two possible stress origins, i.e., oblique plate convergence and ridge collision/indenter tectonics of Chile ridge against Peru-Chile trench, have been emphasized in the present study. Three types of boundary conditions for the three particular models have been applied to calculate stress fields. Models are assumed to be elastic and plane stress condition. Modeling results are presented in terms of four parameters, i. e., orientation of maximum horizontal stress (σHmax), displacement vector, strain distribution, and maximum shear stress (τmax) contour line within the model. The results of the first model with oblique plate convergence show inconsistency between the geometric shape of the LOFZ and the distribution of the four parameters. Although more realistic results are obtained from the second model with normal ridge collision, there are few coincident in the LOFZ geometry and regional stress field. The third model with normal and oblique ridge collision is reasonable in understanding the origin of stress field and geometrical condition in the lithosphere of the LOFZ.

  12. Imaging the mid-crustal low velocity zone of the Altiplano-Puna magma body (Uturuncu volcano) in southern Bolivia from receiver functions

    Science.gov (United States)

    Cooksey, S.; Christensen, D. H.; West, M. E.

    2012-12-01

    Uturuncu volcano is located in the Altiplano-Puna volcanic complex, near the center of the Altiplano-Puna magma body (APMB) in southern Bolivia. The region has exhibited sustained uplift of 1 to 2 cm/yr for several decades over a broad region (70 km diameter). Uturuncu volcano and the surrounding area are the focus of an intensive multi-university study. The centerpiece of this study is a 40-station network of broadband seismometers that were deployed in the spring of 2010. At this time two full years of data have been retrieved from the network. Over 1200 receiver functions were determined from 65 teleseismic earthquakes. Receiver functions from similar back-azimuths and distances were then stacked to produce 49 average receiver functions that are used in this study. P-wave receiver functions clearly delineate the low velocity region associated with the APMB. This mid-crustal low velocity zone is present throughout the study area. While the APMB has been previously noted and described, the current network increases the station density in this region by a factor of 10. The top of the low velocity layer is associated with a large negative Ps arrival at about 2 seconds, corresponding to a depth of about 15 km (although there is scatter and variability in the depth modeling). This negative arrival is followed by a positive Ps arrival at around 3.5 seconds corresponding to the bottom of the low velocity zone at a depth of about 25 km. In general the low velocity zone is around 10-15 km thick, but once again with a fair amount of variability. The low velocity region corresponds well with estimates of the inflation source responsible for the observed uplift, and thus most likely represents an extensive region of partial melt, and potentially magma recharge, at the volcano. Arrivals from the Moho and subducting Nazca plate are obscured by the strong arrivals (including multiple reverberations) from the low velocity layer.

  13. Numerical earthquake model of the 20 April 2015 southern Ryukyu subduction zone M6.4 event and its impact on seismic hazard assessment

    Science.gov (United States)

    Lee, Shiann-Jong

    2015-10-01

    The M6.4 earthquake that took place on the 20 April 2015 off the shore of eastern Taiwan was the largest event in the vicinity of Taiwan during 2015. The mainshock was located in the southern Ryukyu subduction zone, which is the interface between the Philippine Sea Plate and the Eurasian Plate. People in Taipei experienced strong ground shaking for more than 40 s, even though the epicenter was located more than 150 km away. In order to understand the origin of ground motions from this earthquake and how it caused such strong shaking in Taipei, a numerical earthquake model is analyzed, including models of source rupture and wave propagation. First, a joint source inversion was performed using teleseismic body wave and local ground motion data. Source inversion results show that a large slip occurred near the hypocenter, which rapidly released seismic energy in the first 2 s. Then, the rupture propagated toward the shallow fault plane. A large amount of seismic energy was released during this rupture stage that slipped for more than 8 s before the end of the rupture. The estimated stress drop is 2.48 MPa, which is consistent with values for subduction zone earthquakes. Forward simulation using this inverted source rupture model and a 3D seismic velocity model based on the spectral-element method was then performed. Results indicate that the strong ground motion in Taipei resulted from two factors: (1) the Taipei basin amplification effect and (2) the specific source radiation pattern. The results of this numerical earthquake model imply that future subduction zone events that occur in offshore eastern Taiwan are likely to cause relatively strong ground shaking in northern Taiwan, especially in the Taipei metropolitan area.

  14. Present-day stress tensors along the southern Caribbean plate boundary zone from inversion of focal mechanism solutions: A successful trial

    Science.gov (United States)

    Audemard M., Franck A.; Castilla, Raymi

    2016-11-01

    This paper presents a compilation of 16 present-day stress tensors along the southern Caribbean plate boundary zone (PBZ), and particularly in western and along northern Venezuela. As a trial, these new stress tensors along PBZ have been calculated from inversion of 125 focal mechanism solutions (FMS) by applying the Angelier & Mechler's dihedral method, which were originally gathered by the first author and published in 2005. These new tensors are compared to those 59 tensors inverted from fault-slip data measured only in Plio-Quaternary sedimentary rocks, compiled in Audemard et al. (2005), which were originally calculated by several researchers through the inversion methods developed by Angelier and Mechler or Etchecopar et al. The two sets of stress tensors, one derived from geological data and the other one from seismological data, compare very well throughout the PBZ in terms of both stress orientation and shape of the stress tensor. This region is characterized by a compressive strike-slip (transpressional senso lato), occasionally compressional, regime from the southern Mérida Andes on the southwest to the gulf of Paria in the east. Significant changes in direction of the maximum horizontal stress (σH = σ1) can be established along it though. The σ1 direction varies progressively from nearly east-west in the southern Andes (SW Venezuela) to between NW-SE and NNW-SSE in northwestern Venezuela; this direction remaining constant across northern Venezuela, from Colombia to Trinidad. In addition, the σV defined by inversion of focal mechanisms or by the shape of the stress ellipsoid derived from the Etchecopar et al.'s method better characterize whether the stress regime is transpressional or compressional, or even very rarely trantensional at local scale. The orientation and space variation of this regional stress field in western Venezuela results from the addition of the two major neighbouring interplate maximum horizontal stress orientations (

  15. Variations in DBTT and CTOD within weld heat-affected zone of API X65 pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Jang-Bog [Samsung Electronics Co. Ltd., Asan 336-841 (Korea, Republic of); Kim, Woo-sik [Research and Development Center, Korea Gas Corporation, Ansan 425-150 (Korea, Republic of); Jang, Jae-il, E-mail: jijang@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer Fracture resistance of API X65 steel weld HAZ was systematically investigated. Black-Right-Pointing-Pointer Variations in DBTT and CTOD toughness within HAZ were explored. Black-Right-Pointing-Pointer Results were discussed with the additional data from simulated HAZ specimen tests. - Abstract: The fracture resistance of heat-affected zones (HAZs) in girth welded joint of API X65 steel pipeline was systematically investigated. While the change in Charpy impact energy has been typically evaluated in previous studies, here the variations in ductile-to-brittle temperature (DBTT) and crack-tip opening displacement (CTOD) within HAZ were explored. A series of experiments revealed that both values vary dramatically (i.e., DBTT increases and CTOD decreases) as the location approaches the fusion line (FL) and thus the region adjacent to FL exhibited the lowest CTOD and highest DBTT, possibly due to the increasing portion of coarse-grained HAZ. Interestingly, however, even the FL regions still showed moderate toughness at -40 Degree-Sign C {approx} room temperature. Microstructural analysis and additional impact tests using simulated HAZ specimens suggested a possibility that fine-grained HAZs with higher toughness may suppress the brittle fracture from neighboring coarse-grained region.

  16. Numerical simulation of the Iiquating behavior of niobium carbide in heat-affected-zone during welding of a superalloy

    Institute of Scientific and Technical Information of China (English)

    GUO Shaoqing; LI Xiaohong

    2007-01-01

    In order to predict the propensity of a superalloy to beat-affected-zone (HAZ) liquation cracking, Visual FOR-TRAN procedures were developed based on a heat transfer and mass diffusion model and the constitutional liquation of precipitate (NbC) at grain boundaries was simulated numeri-cally. The results show that with the increase in the rate of welding thermal cycle, the solid dissolution of precipitate prior to liquation decreases and the thickness of liquid film produced by constitutional liquation increases. Higher heating rate inhi-bits the further melting of adjacent matrix and the solidification of liquid by liquid-to-7 mode in the subsequent thermal cycle.As a result, the residual liquid film still maintains a great thick-ness at the moment when temperature is down to the euteetic point, which will promote HAZ micro-fissuring. Finally, hot ductility tests on a low-expansion superalloy were performed to verify indirectly the conclusions drawn from the numerical simulation.

  17. Green reconstruction of the tsunami-affected areas in India using the integrated coastal zone management concept.

    Science.gov (United States)

    Sonak, Sangeeta; Pangam, Prajwala; Giriyan, Asha

    2008-10-01

    A tsunami, triggered by a massive undersea earthquake off Sumatra in Indonesia, greatly devastated the lives, property and infrastructure of coastal communities in the coastal states of India, Andaman and Nicobar Islands, Indonesia, Sri Lanka, Malaysia and Thailand. This event attracted the attention of environmental managers at all levels, local, national, regional and global. It also shifted the focus from the impact of human activities on the environment to the impacts of natural hazards. Recovery/reconstruction of these areas is highly challenging. A clear understanding of the complex dynamics of the coast and the types of challenges faced by the several stakeholders of the coast is required. Issues such as sustainability, equity and community participation assume importance. The concept of ICZM (integrated coastal zone management) has been effectively used in most parts of the world. This concept emphasizes the holistic assessment of the coast and a multidisciplinary analysis using participatory processes. It integrates anthropocentric and eco-centric approaches. This paper documents several issues involved in the recovery of tsunami-affected areas and recommends the application of the ICZM concept to the reconstruction efforts.

  18. Effect of Heat Input on Microstructure and Toughness of Coarse Grain Heat Affected Zone in Nb Microalloyed HSLA Steels

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying-qiao; ZHANG Han-qian; LI Jin-fu; LIU Wei-ming

    2009-01-01

    The influence of Nb on microstructure, mechanical property and the transformation kinetics of the coarse grain heat affected zone (CGHAZ) in HSLA steels for different heat inputs, has been investigated. When welded at higher heat inputs (100-60 kJ/cm), impact toughness values of the steel without Nb are much higher than those of the steel with Nb, and the lowest span is 153 J at 60 kJ/cm. But only a little higher values are observed at lower heat inputs (40-30 kJ/cm), and the highest span is 68 J at 30 kJ/cm. Dilatation studies indicate that continuous cooling transformation starting temperatures (Ts) of CGHAZ for the steel with Nb are approximately 15-30 ℃ which are lower than those of the steel without Nb at all heat inputs. For higher heat inputs, Nb in solid solution suppresses ferrite transformation and promotes the formation of granular bainite which has detrimental effect on impact tough-ness. For lower heat inputs higher Charpy impact energy values in the steel with Nb are associated with the formation of low carbon self-tempered martensite.

  19. Test for investigating the hot embrittlement in the heat affected zone of welded joints of austenitic steels

    International Nuclear Information System (INIS)

    12 stabilized and non-stabilized austenitic CrNi steels were tested to compare their deformation properties in the temperature range of 550 to 6500C. In addition to the initial state a structural state was tested, which was intended to simulate by thermal treatment on a Gleeble apparatus (5 sec/13000C/water quenching) the structure in the heat affected zone of a welded joint. For this purpose tensile tests at very low elongation velocity (0.02 mm/min) and creep rupture tests up to durations of about 1000 h were performed. Hardness measurements were performed after ageing and impact toughness was determined at room temperature. Microstructures and fracture surfaces were examinded by optical and electron microscopy. For all steels elongation and reduction of area after fracture in tensile testing at elevated temperatures are markedly reduced compared to room temperature values. After Gleeble heat treatment the above mentioned deformation values are further reduced at elevated temperatures. The strength and the deformation data in creep rupture tests are either slightly reduced or remain unchanged. No particular notch sensitivity was found for any of the steels. (orig./GSCH)

  20. Structure-Property-Fracture Mechanism Correlation in Heat-Affected Zone of X100 Ferrite-Bainite Pipeline Steel

    Science.gov (United States)

    Li, Xueda; Ma, Xiaoping; Subramanian, S. V.; Misra, R. D. K.; Shang, Chengjia

    2015-03-01

    Structural performance of a weld joint primarily depends on the microstructural characteristics of heat-affected zone (HAZ). In this regard, the HAZ in X100 ferrite-bainite pipeline steel was studied by separating the HAZ into intercritically reheated coarse-grained (ICCG) HAZ containing and non-containing regions. These two regions were individually evaluated for Charpy impact toughness and characterized by electron back-scattered diffraction (EBSD). Low toughness of ~50 J was obtained when the notch of impact specimen encountered ICCGHAZ and high toughness of ~180 J when the notch did not contain ICCGHAZ. Fracture surface was ~60 pct brittle in the absence of ICCGHAZ, and 95 pct brittle (excluding shear lip) in the presence of ICCGHAZ in the impact tested samples. The underlying reason is the microstructure of ICCGHAZ consisted of granular bainite and upper bainite with necklace-type martensite-austenite (M-A) constituent along grain boundaries. The presence of necklace-type M-A constituent notably increases the susceptibility of cleavage microcrack nucleation. ICCGHAZ was found to be both the initiation site of the whole fracture and cleavage facet initiation site during brittle fracture propagation stage. Furthermore, the study of secondary microcracks beneath CGHAZ and ICCGHAZ through EBSD suggested that the fracture mechanism changes from nucleation-controlled in CGHAZ to propagation-controlled in ICCGHAZ because of the presence of necklace-type M-A constituent in ICCGHAZ. Both fracture mechanisms contribute to the poor toughness of the sample contained ICCGHAZ.

  1. Nature and evolution of lithospheric mantle beneath the southern Ethiopian rift zone: evidence from petrology and geochemistry of mantle xenoliths

    Science.gov (United States)

    Alemayehu, Melesse; Zhang, Hong-Fu; Sakyi, Patrick Asamoah

    2016-06-01

    Mantle xenoliths hosted in Quaternary basaltic lavas from the Dillo and Megado areas of the southern Ethiopian rift are investigated to understand the geochemical composition and associated processes occurring in the lithospheric mantle beneath the region. The xenoliths are comprised of predominantly spinel lherzolite with subordinate harzburgite and clinopyroxenite. Fo content of olivine and Cr# of spinel for peridotites from both localities positively correlate and suggest the occurrence of variable degrees of partial melting and melt extraction. The clinopyroxene from lherzolites is both LREE depleted (La/Sm(N) = 0.11-0.37 × Cl) and LREE enriched (La/Sm(N) = 1.88-15.72 × Cl) with flat HREEs (Dy/Lu(N) = 0.96-1.31 × Cl). All clinopyroxene from the harzburgites and clinopyroxenites exhibits LREE-enriched (La/Sm(N) = 2.92-27.63.1 × Cl and, 0.45 and 1.38 × Cl, respectively) patterns with slight fractionation of HREE. The 143Nd/144Nd and 176Hf/177Hf ratios of clinopyroxene from lherzolite range from 0.51291 to 0.51370 and 0.28289 to 0.28385, respectively. Most of the samples define ages of 900 and 500 Ma on Sm-Nd and Lu-Hf reference isochrons, within the age range of Pan-African crustal formation. The initial Nd and Hf isotopic ratios were calculated at 1, 1.5, 2 and 2.5 Ga plot away from the trends defined by MORB, DMM and E-DMM which were determined from southern Ethiopian peridotites, thus indicating that the Dillo and Megado xenoliths could have been produced by melt extraction from the asthenosphere during the Pan-African orogenic event. There is no significant difference in 87Sr/86Sr ratios between the depleted and enriched clinopyroxene. This suggests that the melts that caused the enrichment of the clinopyroxene are mainly derived from the depleted asthenospheric mantle from which the xenoliths are extracted. Largely, the mineralogical and isotopic compositions of the xenoliths show heterogeneity of the CLM that could have been produced from various

  2. Use of electromagnetic induction surveys to delimit zones of contrasting tree development in an irrigated olive orchard in Southern Spain.

    Science.gov (United States)

    Pedrera, Aura; Vanderlinden, Karl; Jesús Espejo-Pérez, Antonio; Gómez, José Alfonso; Giráldez, Juan Vicente

    2014-05-01

    Olives are historically closely linked to Mediterranean culture and have nowadays important societal and economical implications. Improving yield and preventing infestation by soil-borne pathogens are crucial issues in maintaining olive cropping competitive. In order to assess both issues properly at the farm or field scale, accurate knowledge of the spatial distribution of soil physical properties and associated water dynamics is required. Conventional soil surveying is generally prohibitive at commercial farms, but electromagnetic induction (EMI) sensors, measuring soil apparent electrical conductivity (ECa) provide a suitable alternative. ECa depends strongly on soil texture and water content and has been used exhaustively in precision agriculture to delimit management zones. The aim of this study was to delimit areas with unsatisfactory tree development in an olive orchard using EMI, and to identify the underlying relationships between ECa and the soil properties driving the spatial tree development pattern. An experimental catchment in S. Spain dedicated to irrigated olive cropping was surveyed for ECa under dry and wet soil conditions (0.06 vs. 0.22 g/g, respectively), using a Dualem 21-S EMI sensor. In addition, ECa and gravimetric soil water content (SWC) was measured at 45 locations throughout the catchment during each survey. At each of these locations, soil profile samples were collected to determine textural class including coarse particles content, organic matter (OM), and bulk density. Measurements for dry soil conditions with the perpendicular coil configuration with a separation of 2.1 m (P2.1) were chosen to make a first assessment of the orchard-growth variability. According to the shape of the histogram, the P2.1 ECa values were classified to delimit three areas in the field for which canopy coverage was estimated. Combining the 4 ECa signals for the wet and dry surveys, a principal component (PC) analysis showed that 91% of the total variance

  3. An Outline of Karst Geomorphology Zoning in the Karst Areas of Southern China%中国南方喀斯特地貌分区纲要

    Institute of Scientific and Technical Information of China (English)

    王世杰; 张信宝; 白晓永

    2015-01-01

    对热带喀斯特地貌形成的动力学机制和任美锷先生提出的喀斯特地貌演化理论展开讨论,并遵循地貌类型的地带性和非地带性规律,根据地貌形态和成因的相似性,提出我国南方喀斯特地貌分区纲要。根据喀斯特地貌的气候类型,南方喀斯特地区分为:热带喀斯特地貌类型区和非热带喀斯特地貌类型区。根据喀斯特地貌形态组合,热带喀斯特地貌类型区再分为:黔中高原浅碟型峰丛洼地,黔-桂斜坡带漏斗型峰丛洼地和广西峰林平原等3个亚区。根据区域地貌形态,非热带喀斯特地貌类型区再分为:川西、滇西北中高山,滇东高原盆谷,北盘江高原峡谷,黔渝川鄂湘接壤的中低山槽谷,湘中、湘南、鄂东中低山丘陵区等5个亚区。%Dynamic mechanism for formation of trdopical karst geomorphology and karst geomorphology evolution, proposed by Prof. Ren mei’e,are discussed in this paper. Based on zonality and anonality laws of geomorphology types and according to similarities of the karst geomorphology and its formation causes,an outline of karst geomor-phology zoning in the karst areas of Southern China is proposed. According to climate types of the karst geomorphol-ogy,the areas are divided into tropical karst geomorphology zone and non-tropical karst geomorphology zone. Ac-cording to karst morphology group,the tropical karst geomorphology zone is divided into the Peak-Cluster Depres-sion subzone of shallow dish type in the middle Guizhou Plateau ;the Peak-Cluster Depression subzone of funnel type in the transition slope between Guizhou Plateau and Gaunxi Hilly plain. According to regional geomorphology, the non-tropical karst geomorphology zone is divided into the medium-high mountain subzone in Western Sichuan and North-western Yunnan;the basin-valley subzone in Eastern Yunnan Plateau;the canyon subzone of Beipan River;the trough valley subzone of the medium

  4. Assessing vulnerability mapping and protection zones of karst spring waters and validating by the joint use of natural and artificial tracers. The case of Auta Spring (Southern Spain)

    Science.gov (United States)

    Marín, Ana Isabel; Mudarra, Matías; Andreo, Bartolomé

    2016-04-01

    Delineation of protection zones for water supply and implementation of proper land-use practices in surrounding areas are crucial aspects for a sustainable use of valuable drinking water resources. This is even more important in karst aquifers, which are particularly sensitive to contamination, having a very low self-cleaning capacity due to their structure and hydrological behavior. Consequently, specific methodologies adapted to the particular characteristics of karst media are necessary. In this work, an approach for protection zoning of the pilot site of Auta karst spring (southern Spain) is proposed, based on the application of COP+K method for contamination vulnerability and validation of results by natural (organic) tracers of infiltration (NO3-, TOC, intrinsic fluorescence) and by a dye tracer test conducted on June, 2011 (injecting 500 mg uranine). The aquifer drained by Auta spring (8.5 km2) presents a complex geological structure, formed by Jurassic dolostones and limestones highly folded and fractured. Recharge takes place by the infiltration of rainfall through karst landforms and also by losses in an adjacent river when it flows over the carbonate outcrops (dye injection point). Drainage is mainly through several springs located at the southwest, including Auta spring and 5 overflow springs. The source vulnerability map obtained by applying COP+K method can be adopted as the baseline to delineate the protection zones, through the conversion from vulnerability classes to degrees of protection. Dye tracer test and natural tracers of infiltration corroborate that aquifer sectors influenced by the river can be extremely vulnerable to pollution, but also well-developed exokarst features. In fact, slight evidences of pollution have been detected during the study period, with relatively-high NO3- contents and high fluorescence linked to bacteriological activity in Auta spring water. The jointly use of natural and artificial tracers constitute a reliable and

  5. Repeated occurrences of methanogenic zones, diagenetic dolomite formation and linked silicate alteration in southern Bering Sea sediments (Bowers Ridge, IODP Exp. 323 Site U1341)

    Science.gov (United States)

    Wehrmann, L. M.; Ockert, C.; Mix, A. C.; Gussone, N.; Teichert, B. M. A.; Meister, P.

    2016-03-01

    Diagenetic precipitates, such as dolomite, and the chemistry of residual deeply buried porewater often represent the only traces of past biogeochemical activity in marine sediments. A 600 m thick sedimentary section, recently drilled at Integrated Ocean Drilling Program (IODP) Site U1341 on Bowers Ridge (southern Bering Sea), provides insight into such a 4.3 Ma old paleo-diagenetic archive. Hard-lithified calcite-dolomite layers, and laminae of disseminated carbonate, were recovered in diatom-rich sediments over a depth range of 400 m. Carbon isotope values of the diagenetic carbonates between -16.6 and -14.4‰ (VPDB) and strontium isotope ratios of dolomites close to past seawater values suggest carbonate precipitation induced by the production of dissolved inorganic carbon (DIC) during elevated rates of organic carbon mineralization, primarily via sulfate reduction, at shallow sediment depth below the paleo-seafloor. Diagenetic carbonates at 280-440 m below seafloor were likely also produced by the intermittent onset of sulfate reduction coupled to the anaerobic oxidation of methane (AOM) at sulfate-methane transition zones (SMTZ). These microbially mediated processes do not occur in the sediment at this site at present but were likely connected to the presence of a methanogenic zone at 2.58-2.51 Ma. A minimum in sulfate concentrations in modern porewaters and low sedimentary Ba/Al ratios resulting from former sulfate depletion are reminiscent of the presence of this large methanogenic zone. The minimum in sulfate concentrations is reflected in a minimum in magnesium concentrations, less radiogenic strontium and isotopically light calcium in the porewater. It is proposed that magnesium was removed from the porewater during carbonate precipitation and volcanic ash alteration which occurred in the former methanogenic zone and also released strontium with a less radiogenic isotope ratio and isotopically light calcium into the porewater. The isotopic composition of

  6. Assessing hyporheic zone dynamics in two alluvial flood plains of the Southern Alps using water temperature and tracers

    Directory of Open Access Journals (Sweden)

    E. Hoehn

    2006-03-01

    Full Text Available Water temperature can be used as a tracer for the interaction between river water and groundwater, interpreting time shifts in temperature signals as retarded travel times. The water temperature fluctuates on different time scales, the most pronounced of which are the seasonal and diurnal ones. While seasonal fluctuations can be found in any type of shallow groundwater, high-frequency components are more typical for freshly infiltrated river water, or hyporheic groundwater, and are thus better suited for evaluating the travel time of the youngest groundwater component in alluvial aquifer systems. We present temperature time series collected at two sites in the alpine floodplain aquifers of the river Brenno in Southern Switzerland. At the first site, we determine apparent travel times of temperature for both the seasonal and high-frequency components of the temperature signals in several wells. The seasonal signal appears to travel more slowly, indicating a mixture of older and younger groundwater components, which is confirmed by sulphate measurements. The travel times of the high-frequency component qualitatively agree with the groundwater age derived from radon concentrations, which exclusively reflects young water components. Directly after minor floods, the amplitude of temperature fluctuations in an observation well nearby the river is the highest. Within a week, the riverbed is being clogged, leading to stronger attenuation of the temperature fluctuations in the observation well. At the second site, very fast infiltration to depths of 1.9m under the riverbed could be inferred from the time shift of the diurnal temperature signal.

  7. Quaternary landscape development, alluvial fan chronology and erosion of the Mecca Hills at the southern end of the San Andreas Fault zone

    Science.gov (United States)

    Gray, Harrison J.; Owen, Lewis; Dietsch, Craig; Beck, Richard A.; Caffee, Marc A.; Finkelman, Robert B.; Mahan, Shannon

    2014-01-01

    Quantitative geomorphic analysis combined with cosmogenic nuclide 10Be-based geochronology and denudation rates have been used to further the understanding of the Quaternary landscape development of the Mecca Hills, a zone of transpressional uplift along the southern end of the San Andreas Fault, in southern California. The similar timing of convergent uplifts along the San Andreas Fault with the initiation of the sub-parallel San Jacinto Fault suggest a possible link between the two tectonic events. The ages of alluvial fans and the rates of catchment-wide denudation have been integrated to assess the relative influence of climate and tectonic uplift on the development of catchments within the Mecca Hills. Ages for major geomorphic surfaces based on 10Be surface exposure dating of boulders and 10Be depth profiles define the timing of surface stabilization to 2.6 +5.6/–1.3 ka (Qyf1 surface), 67.2 ± 5.3 ka (Qvof2 surface), and 280 ± 24 ka (Qvof1 surface). Comparison of 10Be measurements from active channel deposits (Qac) and fluvial terraces (Qt) illustrate a complex history of erosion, sediment storage, and sediment transport in this environment. Beryllium-10 catchment-wide denudation rates range from 19.9 ± 3.2 to 149 ± 22.5 m/Ma and demonstrate strong correlations with mean catchment slope and with total active fault length normalized by catchment area. The lack of strong correlation with other geomorphic variables suggests that tectonic uplift and rock weakening have the greatest control. The currently measured topography and denudation rates across the Mecca Hills may be most consistent with a model of radial topographic growth in contrast to a model based on the rapid uplift and advection of crust.

  8. Feeding strategy of Menticirrhus americanus and Menticirrhus littoralis (Perciformes: Sciaenidae juveniles in a sandy beach surf zone of southern Brazil

    Directory of Open Access Journals (Sweden)

    Fábio L. Rodrigues

    2010-01-01

    Full Text Available The diet and foraging strategy of juvenile Menticirrhus americanus (Linnaeus, 1758 and Menticirrhus littoralis (Holbrook, 1847 were studied, testing the existence of trophic overlap between these species and within different seasons (spring and summer. Individuals were sampled using a beach seine in the surf zone near Rio Grande, state of Rio Grande do Sul, Brazil. Based on Morisita's Simplified Overlap Index and Bootstrapping technique, trophic overlap between species was considered high during the spring (Cik = 0.97 ± 0.07 and low during the summer (Cik = 0.37 ± 0.14. Juveniles shared the same food resources during the spring (FO of amphipods > 0.75, with the M. americanus diet presenting lower prey diversity (N = 7 when compared to M. littoralis (N = 13. In the summer, M. americanus presented a more varied diet (N = 13 than during the spring, suggesting a non-specialized opportunistic diet, whereas M. littoralis continued to show a diversified diet (N = 14. During the summer, M. americanus presented a generalist-opportunist feeding strategy, whereas juvenile M. littoralis tended to be more specialist.

  9. Characterization of the Ni–Mo–Cr superalloy subjected to simulated heat-affected zone thermal cycle treatment

    Energy Technology Data Exchange (ETDEWEB)

    He, Yanming, E-mail: heyanming@zjut.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Yang, Jianguo, E-mail: yangjg@zjut.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Qin, Chunjie [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Chen, Shuangjian [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Gao, Zengliang [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China)

    2015-09-15

    Highlights: • The constitution of Ni–17Mo–7Cr alloy was convincingly ascertained by TEM analysis. • The Ni–17Mo–7Cr alloy was thermally cycled with a peak temperature up to 1350 °C. • The lamellar-like phases in the alloy were firstly determined by TEM and HRTEM. • The formation mechanism for the lamellar-like phases was unveiled rigorously. • Effect of lamellar-like phases on the alloy’s performances was evaluated in depth. - Abstract: A representative Ni–Mo–Cr superalloy with basic composition of Ni–17Mo–7Cr (wt.%) was fabricated in the work and the relationship between the microstructure and mechanical properties while it went through simulated heat-affected zone (HAZ) thermal cycle treatment was investigated. The results reveal that the Ni–Mo–Cr alloy mainly consisted of Ni matrix and MoC carbides. The critical peak temperature that a lamellar-like structure occurred in the alloy was found to be 1300 °C. These products were firstly characterized by transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analysis, and they were essentially Ni matrix and carbides (MoC and chromium carbides) generated through local melting. The equivalent mechanical properties of the alloy relative to that of un-treated alloy were received owing to its unique architecture even the peak temperature during thermal cycle was up to 1350 °C. The results obtained suggests these lamellar-like products dispersed near the fusion line in a Ni–Mo–Cr welded joint will not influence the joint’s mechanical strength and stability while the peak temperature in the HAZ was adjusted below 1350 °C, providing valuable guideline in designing and applying the Ni–Mo–Cr system superalloys.

  10. Characterization of the Ni–Mo–Cr superalloy subjected to simulated heat-affected zone thermal cycle treatment

    International Nuclear Information System (INIS)

    Highlights: • The constitution of Ni–17Mo–7Cr alloy was convincingly ascertained by TEM analysis. • The Ni–17Mo–7Cr alloy was thermally cycled with a peak temperature up to 1350 °C. • The lamellar-like phases in the alloy were firstly determined by TEM and HRTEM. • The formation mechanism for the lamellar-like phases was unveiled rigorously. • Effect of lamellar-like phases on the alloy’s performances was evaluated in depth. - Abstract: A representative Ni–Mo–Cr superalloy with basic composition of Ni–17Mo–7Cr (wt.%) was fabricated in the work and the relationship between the microstructure and mechanical properties while it went through simulated heat-affected zone (HAZ) thermal cycle treatment was investigated. The results reveal that the Ni–Mo–Cr alloy mainly consisted of Ni matrix and MoC carbides. The critical peak temperature that a lamellar-like structure occurred in the alloy was found to be 1300 °C. These products were firstly characterized by transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analysis, and they were essentially Ni matrix and carbides (MoC and chromium carbides) generated through local melting. The equivalent mechanical properties of the alloy relative to that of un-treated alloy were received owing to its unique architecture even the peak temperature during thermal cycle was up to 1350 °C. The results obtained suggests these lamellar-like products dispersed near the fusion line in a Ni–Mo–Cr welded joint will not influence the joint’s mechanical strength and stability while the peak temperature in the HAZ was adjusted below 1350 °C, providing valuable guideline in designing and applying the Ni–Mo–Cr system superalloys

  11. Low-Temperature Sensitization Behavior of Base, Heat-Affected Zone, and Weld Pool in AISI 304LN

    Science.gov (United States)

    Singh, Raghuvir; Das, Gautam; Singh, P. K.; Chattoraj, I.

    2009-05-01

    Present investigations were focused on low-temperature sensitization (LTS) behavior of 304LN stainless steels considered from pipes of two different thicknesses. The specimens for the present study were taken from solution-annealed pipes (of varying thicknesses) and welded pipes (including the heat-affected zone (HAZ)). The specimens were subjected to thermal aging at 400 °C and 450 °C for different durations ranging from 125 to 8000 hours, to evaluate their sensitization susceptibility. The aging durations were worked out to simulate the 30-to-100-year life of the studied stainless steel at 300 °C using the Arrheneous equation and considering the activation energy of 150 kJ/mol. The thermally aged specimens were characterized for their degree of sensitization (DOS) and susceptibility to intergranular corrosion (IGC) by double-loop (DL) electrochemical potentiokinetic reactivation (EPR) and by methods given in the ASTM A262 practices A and E. It has been clearly shown that the weld pool is more sensitive to IGC than are the base and the HAZ at both the aging temperatures (LTS), because they showed IGC cracks during the bending subsequent to the boiling in H2SO4-CuSO4 solution. Both the base and the HAZ of the thicker pipe material showed susceptibility to sensitization, as indicated by the increasing DOS and “dual-type” microstructure during electrolytic oxalic acid (EOA) etching; however, they were found safe from IGC for the studied sensitization times. The susceptibility to sensitization and IGC in the weld pool is related to the presence of copious delta ferrite with chromium diffusivity that is accelerated compared to the austenite phase. The time-temperature-sensitization (TTS) curves were prepared accordingly, based on these results.

  12. Manure placement method influenced growth, phenology and bunch yield of three Musagenotypes in a humid zone of Southern Nigeria

    Directory of Open Access Journals (Sweden)

    A. Tenkouano

    2013-01-01

    top dressing is recommended for sustainable plantain production in the high rainfall region of southern Nigeria.

  13. Diversity, regeneration status and population structure of gum- and resin-bearing woody species in south Omo zone, southern Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Muhamed Adem; Adefires Worku; Mulugeta Lemenih; Wubalem Tadesse; Jürgen Pretzsch

    2014-01-01

    South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats (35 at Hamer and 40 at Bena-Tsemay) each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species (9 at Hamer and 14 at Bena-Tsemay) of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum-and resin-bearing species comprised 56%and 57%of species richness, 48%and 50%of total density per ha, 95%and 98%of basal area, and 64%and 56%of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay (H=2.61, 1.4) than at Hamer (H′=2.48, 1.28), respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.

  14. Contents and toxicity of heavy metals in soils of the zone affected by aerial emissions from the Severonikel Enterprise

    Science.gov (United States)

    Evdokimova, G. A.; Kalabin, G. V.; Mozgova, N. P.

    2011-02-01

    In 2009, the zoning of the terrestrial ecosystems in the area exposed to aerial emissions from the Severonikel Enterprise (Murmansk oblast) was performed on the basis of the parameters characterizing the state of the soils, including the contents of the main heavy metal pollutants and exchangeable calcium and magnesium, the soils' pH, the ratio of the organic to mineral soil components, and the state of the soils' microbiota. Three zones differing in the degree of the soil pollution were delimited. These were the zones of heavy, moderate, and weak pollution, which extended for up to 3, 25, and 50 km from the emission source in the prevailing wind direction. The data on the amount of bacterial and fungal biomass provided evidence of the profound degradation of the soils in the heavily polluted zone. In particular, the biomass of the soil microbiota, including its prokaryotic and eukaryotic components, was two to six times lower in this zone than in the background (control) area. The soils of the heavily polluted zone can be classified as strongly toxic for plants, and most of the soils of the moderately polluted zone also fall into the same category.

  15. Calibrated heat flow model for the determination of different heat-affected zones in single-pass laser-cut CFRP using a cw CO2 laser

    Science.gov (United States)

    Mucha, P.; Berger, P.; Weber, R.; Speker, N.; Sommer, B.; Graf, T.

    2015-03-01

    Laser machining has great potential for automated manufacturing of parts made of carbon-fiber-reinforced plastic (CFRP) due to the nearly force and tool-wear free processing. The high vaporization temperatures and the large heat conductivity of the carbon fibers, however, lead to unintentional heat conduction into the material causing damage in zones close to the process. In this paper, the matrix damage zone (MDZ) is subdivided into a matrix sublimation zone (MSZ) where the matrix material was sublimated and a zone where the temperature temporarily exceeded a value causing structural damage in the matrix. In order to investigate the extent of these zones, a one-dimensional heat flow model was applied, which was calibrated by cutting experiments using temperature sensors embedded in the CFRP samples. The investigations showed that the extents of the MSZ and MDZ are dominated by a total interaction time, which includes the passage of the laser beam and the continued interaction of the cloud of hot ablation products with the carbon fibers at the kerf wall and that from a practical point of view, the experimentally determined effective heat conductivity is suitable for simple estimations of the heat-affected zones in CFRP.

  16. Lateral propagation of active normal faults throughout pre-existing fault zones: an example from the Southern Apennines, Italy

    Science.gov (United States)

    Agosta, Fabrizio; Prosser, Giacomo; Ivo Giano, Salvatore

    2013-04-01

    The main active structures in the Southern Apennines are represented by a set of NW-trending normal faults, which are mainly located in the axial sector of the chain. Evidences arising from neotectonics and seismology show activity of a composite seismic source, the Irpinia - Agri Valley, located across the Campania-Basilicata border. This seismic source is made up of two right-stepping, individual seismic sources forming a relay ramp. Each individual seismic source consists of a series of nearly parallel normal fault segments. The relay ramp area, located around the Vietri di Potenza town, is bounded by two seismic segments, the San Gregorio Magno Fault, to the NW, and the Pergola-Melandro Fault, to the SE. The possible interaction between the two right-stepping fault segments has not been proven yet, since the fault system of the area has never been analyzed in detail. This work is aimed at assessing the geometry of such fault system, inferring the relative age of the different fault sets by studying the crosscutting relationships, characterizing the micromechanics of fault rocks associated to the various fault sets, and understanding the modalities of lateral propagation of the two bounding fault segments. Crosscutting relationships are recognized by combining classical geological mapping with morphotectonic methods. This latter approach, which include the analysis of aerial photographs and field inspection of quaternary slope deposits, is used to identify the most recent structures among those cropping out in the field area. In the relay ramp area, normal faults crosscut different tectonic units of the Apennine chain piled up, essentially, during the Middle to Late Miocene. The topmost unit (only few tens of meter-thick) consists of a mélange containing blocks of different lithologies in a clayish matrix. The intermediate thrust sheet consists of 1-1.5 km-thick platform carbonates of late Triassic-Jurassic age, with dolomites at the base and limestones at the

  17. Geochemistry of the Ophiolite and Island-Arc Volcanic Rocks in the Mianxian-Lueyang Suture Zone,Southern Qinling and Their Tectonic Significance

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Ultrabasic rocks in the Mianxian-Lueyang ophiolitic melange zone include harzburgite and dunite which exhibit LREE depletion with remarkable positive Eu anomaly.The diabase dike swarm shows LREE enrichment but slightly negative Eu anomaly.Metamorphosed volcanic rocks can be divided into two groups in terms of their REE geochemistry and trace element ratios of Ti/V,Th/Ta,Th/Yb and Ta/Yb.One is ths MORB-type basalt with LREE depletion,representing the fragments of oceanic crust and implying an association of the MORB-type ophiolite and an ancient ocean basin between the Qinling and Yangtze plates during the Middle Paleozoic-Early Mesozoic era.The oter comprises the island-arc volcanic rocks including tholeiitic basalt and a large amount of calc-alkaline intermediate-acic volcanic rock,which could not be the component of the ancient oceanic crust but the result of magmatism at the continental margin.This indicates that the Mianxian-Lueyang limited ocean basin had undergone a whole process of development,evolution and vanishing from Devonian-Cretaceous to Permian.And the Qinling area had becone an independent lithospheric microplate,on the southern side of which there were exhibited the tectonic characteristics of active continental margins during the Late Paleozoic-Early Mesozoic.That is to say.the Qinling cannot be simply considered as a result of collision between the Yangtze and North China plates.

  18. Applicability of statistical eruption analysis to the geological record of Villarrica and Lanín volcanoes, Southern Volcanic Zone, Chile

    Science.gov (United States)

    Wehrmann, Heidi; Dzierma, Yvonne

    2011-03-01

    Standard stochastic failure-analysis techniques are applied to the geological eruption records of Villarrica and Lanín volcanoes in the Chilean Southern Volcanic Zone. These statistical methods are used to estimate the probabilities of eruptions large enough to leave a trace in the geological record. For Villarrica, the standard lifetime distributions predict a near 100% probability that such an eruption should have occurred between 489 AD and today. If the VEI = 3 eruptions observed in the historical record are large enough to be preserved in the geological record, the probability of such a future eruption of Villarrica is about 20% in the next 100 years. In the case of Lanín, the applicability of the exponential, Weibull and log-logistic distributions to the geological record is doubtful, since the volcano appears to have experienced alternating high- and low-activity regimes. Only the mixture-of-exponentials distribution can take into account the possible dormancy descending to final extinction, resulting in a probability of about 16% that Lanín will ever erupt again in the future. The contrasting behaviour of the eruption records of these two neighbouring volcanoes in terms of the number of eruptions and the length of the repose-time intervals serves to examine to what extent the method can be applied to geological eruption records. This study contributes to directing statistical eruption analysis towards time scales long enough to investigate large-magnitude eruptions, and it includes the possibility of dormancy/extinction.

  19. Isolation and 16s rdna sequence analysis of bacteria from dieback affected mango orchards in southern pakistan

    International Nuclear Information System (INIS)

    A broad range of microorganisms are involved in various mango plant diseases such as fungi, algae and bacteria. In order to study the role of bacteria in mango dieback, a survey of infected mango plants in southern Pakistan was carried out. A number of bacterial isolates were obtained from healthy looking and infected mango trees, and their characterization was undertaken by colony PCR and subsequent sequence analysis of 16S rDNA. These analyses revealed the presence of various genera including Acinetobacter, Bacillus, Burkholderia, Cronobacter, Curtobacterium, Enterobacter, Erwinia, Exiguobacterium, Halotelea, Lysinibacillus, Micrococcus, Microbacterium, Pantoea, Pseudomonas, Salmonella and Staphylococcus. It is noteworthy that several members of these genera have been reported as plant pathogens. The present study provided baseline information regarding the phytopathogenic bacteria associated with mango trees in southern Pakistan. (author)

  20. Outbreak of Serogroup C Meningococcal Disease Primarily Affecting Men Who Have Sex with Men - Southern California, 2016.

    Science.gov (United States)

    Nanduri, Srinivas; Foo, Chelsea; Ngo, Van; Jarashow, Claire; Civen, Rachel; Schwartz, Ben; Holguin, John; Shearer, Eric; Zahn, Matt; Harriman, Kathleen; Winter, Kathleen; Kretz, Cecilia; Chang, How Yi; Meyer, Sarah; MacNeil, Jessica

    2016-01-01

    During March 4-August 11, 2016, 25 outbreak-associated cases of meningococcal disease, including two deaths (8% case-fatality ratio), were reported in Southern California. Twenty-four of the cases were caused by serogroup C Neisseria meningitidis (NmC) and one by N. meningitidis with an undetermined serogroup (Figure). On June 24, 2016, in response to this increase in NmC cases, primarily among men who have sex with men (MSM) in Los Angeles County, the city of Long Beach, and Orange County, the California Department of Public Health (CDPH) issued a press release and health advisory, declaring an outbreak of NmC in Southern California (1). PMID:27606798

  1. Colorectal Carcinomas in Uyo City, Southern Geopolitical Zone of Nigeria: A Review of Clinicopathological Characteristics and Literature

    Science.gov (United States)

    Abudu, Emmanuel K.; Akinbami, Oluyinka S.

    2016-01-01

    Colorectal carcinomas (CRC) were initially thought to be rare in Africa including Nigeria, but recent studies have shown a reverse trend in our environment. This study is aimed to identify the clinical and pathological characteristics of CRC diagnosed between July 2006 and June 2015 in the University of Uyo Teaching Hospital, and a Private Specialist Laboratory, Uyo, Akwa Ibom State, Nigeria. All histological diagnosed cases of CRC seen in the two laboratories (University teaching and a private facility) in Uyo, Akwa-Ibom state, Nigeria during the study period were retrieved noting their bio-data, pathological and clinical variables. A total of 45 patients of age range 26-80 years with a mean of 55.9 years (SD 3.9) and a male to female ratio of 1.4:1 were seen. The two most common age groups affected in CRCs were 61-70 years (28.9%) and 51-60 years (24.4%) respectively. Majority of CRC patients were older than 40 years (86.7%) with identifiable predisposing factors being tubulo-villous adenoma (4 cases, 8.8%), villous adenoma (2 cases 4.4%), polyposis syndromes (2 cases, 4.4%) and schistosomiasis (1 case, 2.2%). Features of large intestinal obstruction were the most common presenting symptom of CRC (53.3%). Rectal bleeding, alteration in bowel habit and fecal incontinence were other symptoms, accounting for 33.3%, 8.9% and 4.4% of cases respectively. Left-sided CRCs were commoner (68.9%) with the majority appearing as annular-constricting type macroscopically (60.0%). Recto-sigmoid region was the preponderant site involved in CRC (29 cases, 64.5%). Adenocarcinoma (84.4%) was the most frequent histological subtype. Mucinous carcinoma, signet ring carcinoma and carcinoid tumor were other histologic subtypes seen in 8.9, 4.4 and 2.2% of cases respectively. The 22.0% of CRC patients presented at advanced stages of the disease. It can be concluded that majority of CRC patients were older than 40 years (86.7%) with features of intestinal obstruction (53.3%) and

  2. Using U-series and beryllium isotopes to reveal the occurrence and relative timing of crustal and mantle processes in the Southern Volcanic Zone of Chile

    Science.gov (United States)

    Cooper, L. B.; Reubi, O.; Dungan, M. A.; Bourdon, B.; Langmuir, C. H.; Turner, S. J.; Schaefer, J. M.

    2012-12-01

    Magmas erupted from subduction zone volcanoes represent the end products of multiple magmatic processes occurring in the asthenospheric mantle wedge and overlying lithosphere (i.e., fluid addition, melting, assimilation, and crystal fractionation). To resolve the contributions of diverse processes and components, and the relative timing of these events, we have determined U-series activities (U-Th-Ra-Pa) for 60 and 10Be compositions for 20 historic or very young lavas carefully chosen on the basis of major and trace element analyses of 625 samples from six volcanoes in the Andean Southern Volcanic Zone of Chile (37.6-41.1°S: Nevados de Chillán, Antuco, Llaima, Lonquimay, Villarrica, and Osorno). Our dataset demonstrates that each of these volcanoes reflects a unique combination and sequence of magmatic processes that are only revealed through analysis of multiple samples spanning the extent of intra-volcano and intra-eruption chemical variation. Sigmarsson et al. (1990; 2002) identified a regional trend using U-series and Be from mostly single samples, which they interpreted to represent along-strike variations in the flux of slab-derived fluids into the wedge [from 230Th-excess plus 226Ra-deficit plus low 10Be/9Be at Chillán towards progressively higher 238U- and Ra-excesses and 10Be/9Be at Villarrica and Osorno]. These data fall within the much broader array defined by our results, but we infer the operation of assimilation (e.g., Llaima; Reubi et al., 2011) and aging of subduction zone components of variable compositions and proportions in the mantle prior to partial melting as important factors in generating the highly individualized and complex U-series systematics observed at each of these six volcanoes. All of the volcanoes exhibit evidence of assimilation, with the exception of Lonquimay which has undergone mostly closed-system fractional crystallization. At Llaima and Chillán the assimilant is crustal. At Villarica, flux-related melts that dominate in

  3. Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel

    OpenAIRE

    Węglowski M. St.; Zeman M.; Grocholewski A.

    2016-01-01

    In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile...

  4. Timing of Deformation in the Central Metasedimentary Belt Boundary Thrust Zone (CMBbtz), southern Ontario, Canada, from Electron Microprobe Dating of Monazite

    Science.gov (United States)

    Markley, M. J.; Dunn, S. R.; Peck, W. H.; Jercinovic, M. J.; Williams, M. L.

    2015-12-01

    In the Grenville Province of Southern Ontario, the Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a crustal-scale tectonic boundary between the older, granulite-facies Central Gneiss Belt to the NW and the younger, amphibolite-facies Central Metasedimentary Belt to the SE. Although there are a range of tectonic models for the CMBbtz, most workers agree it is a major tectonic boundary that accommodated ductile thrusting and crustal shortening during the Ottawan phase of the Grenville Orogeny (~1080-1020 Ma). Some studies suggest that ductile thrusting in the CMBbtz was roughly synchronous with synorogenic extensional collapse below an orogenic lid. Previous geochronological studies also provide evidence of earlier deformation and/or metamorphic events in the CMBbtz, although the relation between deformation in the CMBbtz to the Elzeviran (~1230 Ma) and Shawinigan (~1180 Ma) orogenies is unclear. Our study is the first to report in situ electron microprobe monazite (mnz) dates from amphibolite-grade ortho- and para-gneisses of the CMBbtz. Our results are broadly consistent with other chronometers. We present dates from 132 age-domains within 83 mnz grains in 14 samples. Although our data provide strong evidence for deformation and metamorphism along the length of the CMBbtz during the Ottawan (1080-1020 Ma), we also report two other clusters of ages: 1140-1110 Ma and 1230-1170 Ma. The latter cluster falls between the widely accepted ranges for the Elzeviran and Shawinigan orogenies. In addition, some individual outcrops, particularly those in Killaloe and Minden, show mnz ages spanning over 200 m.y., and the setting and compositions of individual monazite domains allow us to link mnz growth to episodes of garnet growth during multiple events. Together these data indicate an unexpectedly continuous and long-lived period of deformation and metamorphism in the CMBbtz.

  5. Effect of Phosphorus Fertilizer and Spacing on Growth, Nodulation Count and Yield of Cowpea (Vigna unguiculata (L Walp in Southern Guinea Savanna Agroecological Zone, Nigeria

    Directory of Open Access Journals (Sweden)

    E. Ndor

    2012-07-01

    Full Text Available The experiments were conducted during 2009 and 2010 rainy season at the research and teaching farm of the college of agriculture, Lafia, Nasarawa state, Nigeria. To determine the effect of phosphorus fertilizer and spacing on growth, nodulation count and yield of cowpea (Vigna unguiculata in southern guinea savanna agroecological zone, Nigeria. The treatments consisted of three levels of phosphorus 0, 20 and 40 kg/ha and three levels of spacing: 15x40, 30x60 and 45x80 cm factorially combined to form nine treatments which were laid in a Randomized Complete Block Design (RCBD and replicated three times to form twenty seven plots. The result showed that Phosphorus fertilizer had a significant (p<0.05 effect on the entire growth and yield parameter assessed in both years. 40 kg/ha of phosphorus gave a significantly higher number of nodulation count/plant (34.95 and 32.24, number of pod/plant (20.64 and 20.24, seed weight/plant (39.56 and 37.64, pods weight/plant (51.45 and 45.31 and seed weight/ha (1.56 and 1.52 t/ha in both years. The spacing also had a significant (p<0.05 response on almost the entire growth and yield parameter assessed except on the weight of 100 seeds. Spacing of 30×60 cm did not differ significantly with 45x80 cm which gave similar result in the no. of pod/plant, seed weight/plant, pods weight/plant and seed weight (t/ha in both years.

  6. The affect and importance of the Lichens in the Arid zone conservation and protection of water resource

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-liang; ZHANG Yuan-ming; Adil Abdulla; Anwar Tumur; Abdulla Abbas

    2004-01-01

    Desertification has already become the global social problem. On the Arid zone it has closer relation with the frail ecotope. The system of the arid zone mountain belongs to crisscross between the farming ,forestry and husbandry . The frailty of the ecosystem manifests on the internal frailty, depends on the plant ,intensity of the contradictory between the landscape transitional and natural reservation area,physical weathering strong,the development of the soil surface is slowly but the erode of the rain ,soil erosion very grave. Lichens not only rein force the intensity and depth of the weathering of rocks and formation ,accelerate of the mineral weathering making and accumulating the organic compound, at the same time lichens have strongly water protection abilities and inestimable role in the prevent soil erosion. In this paper we were according to on-the-spot investigation and analysis of the laboratory from 1985 to now on the middle and west of the Mt . Tianshan and Mt. Altay kanas where mainly probe into the significance of the protection water and conservation water resources of the Arid zone. This research works will be provide scientific basis and reference of the government for put into effect ,improving environment of the mountain region ,major construction oasis ecotope and make great efforts for protection desert ecotope.

  7. Characterization of Microstructures across the Heat-Affected Zone of the Modified 9Cr-1Mo Weld Joint to Understand Its Role in Promoting Type IV Cracking

    Science.gov (United States)

    Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Rao, K. Bhanu Sankara; Mannan, S. L.

    2007-01-01

    In the postweld heat-treated (PWHT) fusion welded modified 9Cr-1Mo steel joint, a soft zone was identified at the outer edge of the heat-affected zone (HAZ) of the base metal adjacent to the deposited weld metal. Hardness and tensile tests were performed on the base metal subjected to soaking for 5 minutes at temperatures below Ac1 to above Ac3 and tempering at the PWHT condition. These tests indicated that the soft zone in the weld joint corresponds to the intercritical region of HAZ. Creep tests were conducted on the base metal and cross weld joint. At relatively lower stresses and higher test temperatures, the weld joint possessed lower creep rupture life than the base metal, and the difference in creep rupture life increased with the decrease in stress and increase in temperature. Preferential accumulation of creep deformation coupled with extensive creep cavitation in the intercritical region of HAZ led to the premature failure of the weld joint in the intercritical region of the HAZ, commonly known as type IV cracking. The microstructures across the HAZ of the weld joint have been characterized to understand the role of microstructure in promoting type IV cracking. Strength reduction in the intercritical HAZ of the joint resulted from the combined effects of coarsening of dislocation substructures and precipitates. Constrained deformation of the soft intercritical HAZ sandwich between relatively stronger constitutes of the joint induced creep cavitation in the soft zone resulting in premature failure.

  8. Climate, Soil Management, and Cultivar Affect Fusarium Head Blight Incidence and Deoxynivalenol Accumulation in Durum Wheat of Southern Italy.

    Science.gov (United States)

    Scala, Valeria; Aureli, Gabriella; Cesarano, Gaspare; Incerti, Guido; Fanelli, Corrado; Scala, Felice; Reverberi, Massimo; Bonanomi, Giuliano

    2016-01-01

    Fusarium head blight (FHB) is a multifaceted disease caused by some species of Fusarium spp. A huge production of mycotoxins, mostly trichothecenes, often accompanied this disease. Amongst these toxic compounds, deoxynivalenol (DON) and its derivatives represent a major issue for human as well as for animal health and farming. Common and durum wheat are amongst the hosts of trichothecene-producing Fusaria. Differences in susceptibility to fungal infection and toxin accumulation occur in wheat cultivars. Recently, increasing incidence and severity of Fusarium infection and a higher DON accumulation in durum wheat were observed in Italy, especially in Northern regions. In this study, we analyzed wheat yield, technological parameters, the incidence of Fusarium infection and DON content in kernel samples of durum wheat coming from three locations of Southern Italy with different climatic conditions and grown during two seasons, with two methods of cultivation. Four different durum wheat cultivars prevalently cultivated in Southern Italian areas were chosen for this study. Our analysis showed the effects of environment and cultivar types on wheat productivity and key technological parameters for the quality level of the end-product, namely pasta. Notably, although a low rate of mycotoxin contamination in all study sites was assessed, an inverse relation emerged between fungal infection/DON production and durum wheat yield. Further, our study pinpoints the importance of environment conditions on several quality traits of durum wheat grown under Mediterranean climate. The environmental conditions at local level (microscale) and soil management practices may drive FHB outbreak and mycotoxin contamination even in growing area suitable for cropping this wheat species. PMID:27446052

  9. Climate, Soil Management, and Cultivar Affect Fusarium Head Blight Incidence and Deoxynivalenol Accumulation in Durum Wheat of Southern Italy

    Science.gov (United States)

    Scala, Valeria; Aureli, Gabriella; Cesarano, Gaspare; Incerti, Guido; Fanelli, Corrado; Scala, Felice; Reverberi, Massimo; Bonanomi, Giuliano

    2016-01-01

    Fusarium head blight (FHB) is a multifaceted disease caused by some species of Fusarium spp. A huge production of mycotoxins, mostly trichothecenes, often accompanied this disease. Amongst these toxic compounds, deoxynivalenol (DON) and its derivatives represent a major issue for human as well as for animal health and farming. Common and durum wheat are amongst the hosts of trichothecene-producing Fusaria. Differences in susceptibility to fungal infection and toxin accumulation occur in wheat cultivars. Recently, increasing incidence and severity of Fusarium infection and a higher DON accumulation in durum wheat were observed in Italy, especially in Northern regions. In this study, we analyzed wheat yield, technological parameters, the incidence of Fusarium infection and DON content in kernel samples of durum wheat coming from three locations of Southern Italy with different climatic conditions and grown during two seasons, with two methods of cultivation. Four different durum wheat cultivars prevalently cultivated in Southern Italian areas were chosen for this study. Our analysis showed the effects of environment and cultivar types on wheat productivity and key technological parameters for the quality level of the end-product, namely pasta. Notably, although a low rate of mycotoxin contamination in all study sites was assessed, an inverse relation emerged between fungal infection/DON production and durum wheat yield. Further, our study pinpoints the importance of environment conditions on several quality traits of durum wheat grown under Mediterranean climate. The environmental conditions at local level (microscale) and soil management practices may drive FHB outbreak and mycotoxin contamination even in growing area suitable for cropping this wheat species. PMID:27446052

  10. Across the southern Andes on fin: glacial refugia, drainage reversals and a secondary contact zone revealed by the phylogeographical signal of Galaxias platei in Patagonia.

    Science.gov (United States)

    Zemlak, Tyler S; Habit, Evelyn M; Walde, Sandra J; Battini, Miguel A; Adams, Emily D M; Ruzzante, Daniel E

    2008-12-01

    We employed DNA sequence variation at two mitochondrial (control region, COI) regions from 212 individuals of Galaxias platei (Pisces, Galaxiidae) collected throughout Patagonia (25 lakes/rivers) to examine how Andean orogeny and the climatic cycles throughout the Quaternary affected the genetic diversity and phylogeography of this species. Phylogenetic analyses revealed four deep genealogical lineages which likely represent the initial division of G. platei into eastern and western lineages by Andean uplift, followed by further subdivision of each lineage into separate glacial refugia by repeated Pleistocene glacial cycles. West of the Andes, refugia were likely restricted to the northern region of Patagonia with small relicts in the south, whereas eastern refugia appear to have been much larger and widespread, consisting of separate northern and southern regions that collectively spanned most of Argentinean Patagonia. The retreat of glacial ice following the last glacial maximum allowed re-colonization of central Chile from nonlocal refugia from the north and east, representing a region of secondary contact between all four glacial lineages. Northwestern glacial relicts likely followed pro-glacial lakes into central Chilean Patagonia, whereas catastrophic changes in drainage direction (Atlantic --> Pacific) for several eastern palaeolakes were the likely avenues for invasions from the east. These mechanisms, combined with evidence for recent, rapid and widespread population growth could explain the extensive contemporary distribution of G. platei throughout Patagonia. PMID:19017262

  11. Basaltic rocks from the Andean Southern Volcanic Zone: Insights from the comparison of along-strike and small-scale geochemical variations and their sources

    Science.gov (United States)

    Hickey-Vargas, Rosemary; Holbik, Sven; Tormey, Daniel; Frey, Frederick A.; Moreno Roa, Hugo

    2016-08-01

    The origin of spatial variations in the geochemical characteristics of volcanic rocks erupted in the Andean Southern Volcanic Zone (SVZ) has been studied by numerous researchers over the past 40 years. Diverse interpretations for along-strike, across-strike, and small-scale variations have been proposed. In this paper, we review geochemical data showing along-strike geochemical variations and address the processes causing such trends. We compare large- and small-scale changes of the same geochemical parameters in basaltic rocks in order to use spatial scale as a tool for isolating processes that may have the same result. Along-strike geochemical variations in the SVZ are expected, due to 1) greater thickness or age of the sub-arc continental crust and mantle lithosphere in the Northern SVZ (NSVZ; 33°S-34°30‧S) and Transitional SVZ (TSVZ; 34°30‧S-37°S) compared with the Central SVZ (CSVZ; 37°S-41.5°S) and Southern SVZ (SSVZ: 41.5°S-46°S); and 2) along-strike changes of the subducting Nazca plate and overlying asthenosphere. Basalts and basaltic andesites erupted at volcanic front stratovolcanoes define several along-strike geochemical trends: 1) higher 87Sr/86Sr and lower 143Nd/144Nd at volcanoes in the NSVZ compared with the TSVZ, CSVZ, and SSVZ; 2) higher and more variable La/Yb at volcanoes in the NSVZ and TSVZ compared with the CSVZ and SSVZ; 3) lower 87Sr/86Sr for a given 143Nd/144Nd at volcanoes in the TSVZ compared with the CSVZ and SSVZ; and 4) large values for time-sensitive subduction tracers such as 10Be/9Be and (238U/230Th) at some volcanoes in the CSVZ, but not in the NSVZ and TSVZ. Geochemical parameters that distinguish the TSVZ from the CSVZ and SSVZ are also found within the CSVZ at small basaltic eruptive centers (SEC) aligned with the Liquiñe-Ofqui Fault System (LOFS), which extends from 38°S to the southernmost SVZ. Our interpretation is that CSVZ magmas with strong time-sensitive subduction tracers represent the ambient subduction

  12. Modification of adrenergic regulation of heart function affected by radioecological factors within the ten-kilometer zone of Chernobyl disaster

    International Nuclear Information System (INIS)

    Rats kept the ten-kilometer zone of Chernobyl disaster over a period of 30 days exhibited a decreased heart function response to β-adrenoreceptor stimulus, reduced density of the receptor structures in cardiomyocytes and their affinity to specific agonists. The number of β-adrenoreceptors in myocardium cells was restored in 6 months, but their affinity and heart function response to the effect of β-adrenoagonists remained decreased. No significvant changes were observed in regulation influenced indirectly via α-adrenoreceptors. 13 refs., 1 fig., 1 tab

  13. Prevalence and factors associated with trachoma among children aged 1–9 years in Zala district, Gamo Gofa Zone, Southern Ethiopia

    Science.gov (United States)

    Mengistu, Kassahun; Shegaze, Mulugeta; Woldemichael, Kifle; Gesesew, Hailay; Markos, Yohannes

    2016-01-01

    Background Trachoma is the leading cause of preventable blindness worldwide. It is common in areas where people are socioeconomically deprived. Globally, approximately 1.2 billion people live in trachoma-endemic areas, in which, 40.6 million individuals have active trachoma and 8.2 million have trichiasis. According to the World Health Organization’s 2007 report, globally close to 1.3 million people are blind due to trachoma, while approximately 84 million suffer from active trachoma. The National Survey (2007) of Ethiopia showed a prevalence of 40.1% active trachoma among children aged 1–9 years. Trachoma is still endemic in most parts of Ethiopia. Objective To assess prevalence of trachoma and factors associated with it among children aged 1–9 years in Zala district, Gamo Gofa Zone, Southern Nations, Nationalities, and Peoples’ Region. Methods A community-based cross-sectional study was conducted in Zala district from February 28 to March 26, 2014. A total of 611 children were examined for trachoma based on the simplified World Health Organization 1983 classification. A multistage stratified sampling technique with a systematic random sampling technique was used to select study participants. Data were collected by using a semistructured pretested questionnaire and clinical eye examination. The data were entered using EpiData version 3.1 and analyzed using SPSS version 16. Multivariable logistic regression analysis was used to identify independently associated factors. Results The overall prevalence of active trachoma cases was 224 (36.7%) consisting of 207 (92.4%) trachomatous follicles, eight (3.6%) trachomatous intense, and nine (4.0%) combination of trachomatous follicle and trachomatous intense. Inadequate knowledge of family head about trachoma (adjusted odds ratio [AOR] =2.8 [95% CI: 1.9, 4.2]); ≤10 m latrine distance (AOR =1.6 [95% confidence interval {CI}: 1.09, 2.4]); presence of above two preschool children (AOR =2.2 [95% CI: 1.3, 3.7]), flies

  14. Brittle deformation in Southern Granulite Terrane (SGT): A study of pseudotachylyte bearing fractures along Gangavalli Shear Zone (GSZ), Tamil Nadu, India.

    Science.gov (United States)

    mohan Behera, Bhuban; Thirukumaran, Venugopal; Biswal, Tapas kumar

    2016-04-01

    High grade metamorphism and intense deformation have given a well recognition to the Southern Granulite Terrane (SGT) in India. TTG-Charnockite and basic granulites constitute the dominant lithoassociation of the area. Dunite-peridotite-anorthosite-shonkinite and syenites are the intrusives. TTG-charnockite-basic granulite have undergone F1 (isoclinal recumbent), F2 (NE-SW) and F3 (NW-SE) folds producing several interference pattern. E-W trending Neoarchean and Palaeoproterozoic Salem-Attur Shear Zone exhibits a low angle ductile thrust as well as some foot print of late stage brittle deformation near Gangavalli area of Tamil Nadu. The thrust causes exhumation of basic granulites to upper crust. Thrusting along the decollement has retrograded the granulite into amphibolite rock. Subsequently, deformation pattern of Gangavalli area has distinctly marked by numerous vertical to sub-vertical fractures mostly dominating along 0-15 and 270-300 degree within charnockite hills that creates a maximum stress (σ1) along NNW and minimum stress (σ3) along ENE. However, emplacement of pseudotachylyte vein along N-S dominating fracture indicates a post deformational seismic event. Extensive fractures produce anastomose vein with varying thickness from few millimeters to 10 centimeters on the outcrop. ICP-AES study results an isochemical composition of pseudotachylyte vein that derived from the host charnockitic rock where it occurs. But still some noticeable variation in FeO-MgO and Na2O-CaO are obtained from different parts within the single vein showing heterogeneity melt. Electron probe micro analysis of thin sections reveals the existence of melt immiscibility during its solidification. Under dry melting condition, albitic rich melts are considered to be the most favorable composition for microlites (e.g. sheaf and acicular micro crystal) re-crystallization. Especially, acicular microlites preserved tachylite texture that suggest its formation before the final coagulation

  15. Geochemical and Tectonic Evidence for the Role of Crustal Thickening and Forearc Subduction Erosion in Miocene to Recent Andean Southern Volcanic Zone Magmas

    Science.gov (United States)

    Kay, S. M.; Godoy, E.

    2002-12-01

    Key to understanding temporal and spatial variations in Andean-type margin magmas is identifying their mantle and crustal sources in well constrained tectonic settings. A study of Andean Southern Volcanic Zone (SVZ) Early Miocene to Recent magmas in an west to east transect near 34° S points to a linked role for crustal thickening and forearc subduction erosion. The whole rock and isotopic chemistry of these magmas show a trend from Early Miocene tholeiitic sequences with low pressure pyroxene-bearing residual mineral assemblages and more depleted isotopic signatures (87Sr/^{86}Sr ~ 0.7036; ɛ Nd ~ +6 to +4; 206Pb/^{204}Pb ~ 18.5) to Pliocene/Recent high-K calc-alkaline sequences with high pressure garnet-bearing residual mineral assemblages and enriched isotopic signatures (87Sr/^{86}Sr ~ 0.7042; ɛ Nd ~ +1 to 0; 206Pb/^{204}Pb ~ 18.6). Relatively abrupt breaks in this sequence at ~ 19 to 15 Ma and ~ 7 to 4 Ma coincide with an early Miocene extensional to compressional deformational switch and major Late Miocene out-of-sequence thrusting that accompany eastward shifts of ~ 35 and ~ 50 km of the arc front and peaks in uplift history. These changes are consistent with peaks in forearc subduction erosion that introduce continental crust into subcrustal magma sources and in backarc shortening that enhance MASH processes in a thickening crust. Shifts to higher pressure chemical signatures and isotopic enrichment as frontal arc magmatism wanes in the west and migrates eastward fit with continental crust entering subcrustal magma sources. The projections of extinct arc fronts near 34° S into chemically equivalent units to the south indicate an ~ 35 km shift of the arc front north of 36.5° S at ~ 19 to 15 Ma and another ~ 50 km shift north of 34.5° S between ~ 7 to 4 Ma. These SVZ shifts coincide with major tectonic changes along the Andean margin that are best related to variations in plate convergence parameters.

  16. Prevalence of gastrointestinal parasites and Cryptosporidium species in extensively managed pigs in Mekelle and urban areas of southern zone of Tigray region, Northern Ethiopia

    Directory of Open Access Journals (Sweden)

    Zewdneh Tomass

    Full Text Available Aim: The objective of this study was to investigate prevalence of gastrointestinal parasites and Cryptosporidium species in extensively managed pigs in Mekelle and urban areas of southern zone of Tigray Region, Ethiopia during June - September, 2012. Material and methods: Seven hundred fourteen pigs of different ages and sexes were selected for fecal sample collection. Fecal samples were collected from the rectum of pigs with strict sanitation. A total of 25 soil samples were also collected from backyards of pig pens using clean zipped plastic bags. Both fecal and soil samples were examined for eggs and cysts of GIT parasites by flotation and sedimentation techniques. Modified Ziehl – Neelsen technique was used to examine oocysts of Cryptosporidium species from 276 randomly selected fecal samples. Results: Out of 714 pigs examined through flotation and sedimentation, 27.3% were infected by at least one gastrointestinal parasite. Ascaris suum (25.9% was the most prevalent parasite followed by Fasciola hepatica (1.8%, Eimeria spp. (1.7% and Trichuris suis (0.3%. There was no significant association between sex and prevalence of parasites ÷2[df 1] = 1.921; P=0.166. Contrary to this, age of pigs had effect on prevalence of parasites ÷2[df 2] = 8.376; P=0.015. About 7% of pigs examined were positive for oocysts of Cryptosporidium spp. Moreover, 72% of the soil samples found to be contaminated with eggs of Ascaris spp. in the study area. Apart from causing morbidity in the infected pigs, the potential of Ascaris of pigs to infect man and vice versa together with poor environmental hygiene, may complicate the epidemiology and control of Ascariasis in the study areas. Extensively managed pigs may also act as potential reservoirs for zoonoses of Cryptosporidium species. Conclusion: It is concluded that further investigations are crucial on molecular characterization of Ascaris and Cryptosporidium isolates of extensively managed pigs to determine the

  17. Heavy metal contamination of agricultural soils affected by mining activities around the Ganxi River in Chenzhou, Southern China.

    Science.gov (United States)

    Ma, Li; Sun, Jing; Yang, Zhaoguang; Wang, Lin

    2015-12-01

    Heavy metal contamination attracted a wide spread attention due to their strong toxicity and persistence. The Ganxi River, located in Chenzhou City, Southern China, has been severely polluted by lead/zinc ore mining activities. This work investigated the heavy metal pollution in agricultural soils around the Ganxi River. The total concentrations of heavy metals were determined by inductively coupled plasma-mass spectrometry. The potential risk associated with the heavy metals in soil was assessed by Nemerow comprehensive index and potential ecological risk index. In both methods, the study area was rated as very high risk. Multivariate statistical methods including Pearson's correlation analysis, hierarchical cluster analysis, and principal component analysis were employed to evaluate the relationships between heavy metals, as well as the correlation between heavy metals and pH, to identify the metal sources. Three distinct clusters have been observed by hierarchical cluster analysis. In principal component analysis, a total of two components were extracted to explain over 90% of the total variance, both of which were associated with anthropogenic sources.

  18. How Land Concessions Affect Places Elsewhere: Telecoupling, Political Ecology, and Large-Scale Plantations in Southern Laos and Northeastern Cambodia

    Directory of Open Access Journals (Sweden)

    Ian G. Baird

    2015-05-01

    Full Text Available Over the last decade considerable research has been conducted on the development and the impacts of large-scale economic land concessions for plantations in Laos and Cambodia. These studies have variously illustrated that concessions frequently result in serious negative impacts on local people and the environment, often leading to dramatic transformations of landscapes and livelihoods. As important as this research has been, these studies have largely focused on the immediate impacts of the “enclosure” process associated with gaining access to land by investors. In this study we take a different approach, investigating the implications of large-scale land concessions in southern Laos and northeastern Cambodia with regard to places outside of actual concession areas, both within the countries where the concessions are located and beyond. These links have been referred to as “teleconnections” or “telecoupling”, and adopting a “telecoupling” approach allows us to focus on particular relations between land-use change in one location and land-use change elsewhere, either nearby or distant, as the result of large-scale plantation development, both during the early plantation development period, and later when plantations are productive. It also provides opportunities to engage with Land Change Science (LCS through Political Ecology (PE.

  19. Prevalence and factors associated with trachoma among children aged 1–9 years in Zala district , Gamo Gofa zone, Southern Ethiopia

    Directory of Open Access Journals (Sweden)

    Mengistu K

    2016-08-01

    Full Text Available Kassahun Mengistu1 Mulugeta Shegaze2 Kifle Woldemichael3 Hailay Gesesew3,4 Yohannes Markos5 1Department of Zonal Health Office, Gamo Goffa Zone, Arba Minch, Ethiopia; 2Department of Nursing, Arba Minch University, Arba Minch, Ethiopia; 3Department of Epidemiology, Jimma University, Jimma, Ethiopia; 4Discipline of Public Health, Flinders University, Adelaide, Australia; 5Department of Medical Physiology, Jimma University, Jimma, Ethiopia Background: Trachoma is the leading cause of preventable blindness worldwide. It is common in areas where people are socioeconomically deprived. Globally, approximately 1.2 billion people live in trachoma-endemic areas, in which, 40.6 million individuals have active trachoma and 8.2 million have trichiasis. According to the World Health Organization’s 2007 report, globally close to 1.3 million people are blind due to trachoma, while approximately 84 million suffer from active trachoma. The National Survey (2007 of Ethiopia showed a prevalence of 40.1% active trachoma among children aged 1–9 years. Trachoma is still endemic in most parts of Ethiopia.Objective: To assess prevalence of trachoma and factors associated with it among children aged 1–9 years in Zala district, Gamo Gofa Zone, Southern Nations, Nationalities, and Peoples’ Region.Methods: A community-based cross-sectional study was conducted in Zala district from February 28 to March 26, 2014. A total of 611 children were examined for trachoma based on the simplified World Health Organization 1983 classification. A multistage stratified sampling technique with a systematic random sampling technique was used to select study participants. Data were collected by using a semistructured pretested questionnaire and clinical eye examination. The data were entered using EpiData version 3.1 and analyzed using SPSS version 16. Multivariable logistic regression analysis was used to identify independently associated factors.Results: The overall prevalence of

  20. Micromechanism of Decrease of Impact Toughness in Coarse-Grain Heat-Affected Zone of HSLA Steel with Increasing Welding Heat Input

    Science.gov (United States)

    Cao, R.; Li, J.; Liu, D. S.; Ma, J. Y.; Chen, J. H.

    2015-07-01

    This paper analyzes the micromechanism of decrease of impact toughness with increasing the welding heat input in coarse-grain heat-affected zone (CGHAZ) of a low-alloy high-strength ship-building steel plate. By comparing the microstructures, measuring the extending length of the fibrous crack, identifying the critical event of cleavage fracture, measuring the critical length, and calculating the local cleavage fracture stress σ f, and then using the basic principles of the micromechanism of cleavage fracture, this work reveals the essential causes of deteriorated toughness in the CGHAZ of high-strength steel welded joints.

  1. Impact of Land-use Systems on some Physical and Chemical Soil Properties of an Oxisol in the Humid Forest Zone of Southern Cameroon

    Directory of Open Access Journals (Sweden)

    Birang, AM.

    2009-01-01

    Full Text Available A field study was carried out in the village Ngoungoumou in the humid forest zone of Cameroon to assess changes in particle size distribution and soil chemical properties in relation to different land-use systems. These strongly acid soils are mainly composed of clay and sand, and are generally devoid of crop nutrients at the benefit of exchangeable Al occupying the nearly entire exchange complex. The major portion of the nutrients is stored in the top-soil, together with the organic matter. Land-use systems significantly affected the clay, the silt and the sand fractions. Sand and silt decreased with the soil depth whereas clay increased with it. Soil pH, total N, organic carbon, available P, exchangeable Ca, exchangeable Al, sum of bases, ECEC and Al saturation significantly differed with the land-use systems. Al saturation increased with soil depth, and the top-soils presented acidity problems while the sub-soils exhibited Al toxicity. Chromolaena odorata fallows presented relative higher soil fertility, secondary forests and cocoa plantations the lower. Utilization of harvest residues, wood ash or lime; Ca, N, P, K and Mg fertilizations according to crop requirement; acidtolerant crops and N fixing trees for acid soils appear to be the most appropriate soil management options.

  2. Spatio-temporal assessment of soil erosion risk in different agricultural zones of the Inle Lake region, southern Shan State, Myanmar.

    Science.gov (United States)

    Htwe, Thin Nwe; Brinkmann, Katja; Buerkert, Andreas

    2015-10-01

    Myanmar is one of Southeast Asia's climatically most diverse countries, where sheet, rill, and gully erosion affect crop yields and subsequently livelihood strategies of many people. In the unique wetland ecosystem of Inle Lake, soil erosion in surrounding uplands lead to sedimentation and pollution of the water body. The current study uses the Revised Universal Soil Loss Equation (RUSLE) to identify soil erosion risks of the Inle Lake region in space and time and to assess the relationship between soil erosion and degradation for different agricultural zones and cropping systems. Altogether, 85% of soil losses occurred on barren land along the steep slopes. The hotspot of soil erosion risk is situated in the western uplands characterized by unsustainable land use practices combined with a steep topography. The estimated average soil losses amounted to 19.9, 10.1, and 26.2 t ha(-1) yr(-1) in 1989, 2000, and 2009, respectively. These fluctuations were mainly the results of changes in precipitation and land cover (deforestation (-19%) and expansion of annual cropland (+35%) from 1989 to 2009). Most farmers in the study area have not yet adopted effective soil protection measures to mitigate the effects of soil erosion such as land degradation and water pollution of the lake reservoir. This urgently needs to be addressed by policy makers and extension services. PMID:26350794

  3. Winter climate affects long-term trends in stream water nitrate in acid-sensitive catchments in southern Norway

    Directory of Open Access Journals (Sweden)

    H. A. de Wit

    2008-03-01

    Full Text Available Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Long-term trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two sites, stream water NO3 export declined ca 50% over a period of 25 years while in the other sites NO3 export increased with roughly 20%. Discharge and N deposition alone were poor predictors of these trends. The most distinct trends in NO3 were found in winter and spring. Empirical models explained between 45% and 61% of the variation in weekly concentrations of NO3, and described both upward and downward seasonal trends tolerably well. Key explaining variables were snow depth, discharge, temperature and N deposition. All catchments showed reductions in snow depth and increases in winter discharge. In two inland catchments, located in moderate N deposition areas, these climatic changes appeared to drive the distinct decreases in winter and spring concentrations and fluxes of NO3. In a coast-near mountainous catchment in a low N deposition area, these climatic changes appeared to have the opposite effect, i.e. lead to increases in especially winter NO3. This suggests that the effect of a reduced snow pack may result in both decreased and increased catchment N leaching depending on interactions with N deposition, soil temperature regime and winter discharge.

  4. Winter climate affects long-term trends in stream water nitrate in acid-sensitive catchments in southern Norway

    Directory of Open Access Journals (Sweden)

    H. A. de Wit

    2007-09-01

    Full Text Available Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Long-term trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two sites, stream water NO3 export declined ca 50% over a period of 25 years while in the other sites NO3 export increased with roughly 20%. Discharge and N deposition alone were poor predictors of these trends. The most distinct trends in NO3 were found in winter and spring. Empirical models explained between 45% and 61% of the variation in weekly concentrations of NO3, and described both upward and downward seasonal trends tolerably well. Key explaining variables were snow depth, discharge, temperature and N deposition. All catchments showed reductions in snow depth and increases in winter discharge. In two inland catchments, located in moderate N deposition areas, these climatic changes appeared to drive the distinct decreases in winter and spring concentrations and fluxes of NO3. In a coast-near mountainous catchment in a low N deposition area, these climatic changes appeared to have the opposite effect, i.e. lead to increases in especially winter NO3. This suggests that the effect of a reduced snow pack may result in both decreased and increased catchment N leaching depending on interactions with N deposition, soil temperature regime and winter discharge.

  5. Physical factors affecting the abundance and species richness of fishes in the shallow waters of the southern Bothnian Sea (Sweden)

    Science.gov (United States)

    Thorman, Staffan

    1986-03-01

    The relationship between the composition of the fish assemblages and the abiotic environment in seven shallow areas within the same geographical range in the southern Bothnian Sea were studied in May, July, September and November 1982. Eighteen species were found in the areas and the major species were Pungitius pungitius (L.), Pomatoschistus minutus (Pallas), Gasterosteus aculeatus (L.), Phoxinus phoxinus (L.), Pomatoschistus microps (Krøyer) and Gobius niger L. The main purpose of the study was to examine the possible effects of exposure, organic contents in sediments and habitat heterogeneity on species richness and abundance of the assemblages. There was a negative correlation between the organic contents of the sediment and exposure. There were no significant correlations between exposure, organic contents, size of the areas and species numbers but habitat heterogeneity was positively correlated with species number. There were no correlations between fish abundance and heterogeneity of the areas. Negative correlations occurred between the exposure of the areas and fish abundance. The amounts of the pooled benthic fauna were negatively correlated to the exposure. The species/area hypothesis finds no support in the results, because there was no correlation between habitat heterogeneity of an area and its size. The effective fetch combined with the heterogeneity measurement of the areas seemed to be useful indicators of the species composition and fish abundance. Habitat heterogeneity and exposure were the most important structuring factors of these shallow water fish assemblages during the ice-free period and within the local geographical range. The assemblages consist of a mixture of species with marine or limnic origin and they have probably not evolved in the Bothnian Sea or together. They are most likely regulated by their physiological plasticity and not by interactions with other species.

  6. Cleavage Fracture Initiation at M-A Constituents in Intercritically Coarse-Grained Heat-Affected Zone of a HSLA Steel

    Science.gov (United States)

    Mohseni, Peyman; Solberg, Jan Ketil; Karlsen, Morten; Akselsen, Odd Magne; Østby, Erling

    2014-01-01

    Local brittle zones, i.e., martensite-austenite (M-A) islands, are formed within the coarse-grained heat-affected zone (CGHAZ) and the intercritically reheated CGHAZ (ICCGHAZ) during welding of many HSLA steels. In the current study, the M-A constituents in the microstructure of simulated ICCGHAZ of an API X80 pipeline steel were investigated using transmission electron microscopy and scanning electron microscopy. The focused ion beam technique was applied to make TEM specimens of M-A constituents that were located in the initiation sites of cleavage cracks. The main purpose of the study was to identify crack-initiation sites of cleavage fracture in ICCGHAZ and to prove the presence of M-A constituents in such initiation sites. Twinned martensite was detected in all local brittle zones that were investigated in the current study, demonstrating that they are M-A constituents. It was also demonstrated that the fracture initiation occurred preferentially at M-A constituents by a debonding mechanism rather than cracking of the M-A constituents.

  7. Institutional Delivery Service Utilization among Women from Rural Districts of Wolaita and Dawro Zones, Southern Ethiopia; a Community Based Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Mihiretu Alemayehu Arba

    Full Text Available The highest number of maternal deaths occur during labour, delivery and the first day after delivery highlighting the critical need for good quality care during this period. Therefore, for the strategies of institutional delivery to be effective, it is essential to understand the factors that influence individual and household factors to utilize skilled birth attendance and institutions for delivery. This study was aimed to assess factors affecting the utilization of institutional delivery service of women in rural districts of Wolaita and Dawro Zones.A community based cross-sectional study was done among mothers who gave birth within the past one year preceding the survey in Wolaita and Dawro Zones, from February 01 -April 30, 2015 by using a three stage sampling technique. Initially, 6 districts were selected randomly from the total of 17 eligible districts. Then, 2 kebele from each district was selected randomly cumulating a total of 12 clusters. Finally, study participants were selected from each cluster by using systematic sampling technique. Accordingly, 957 mothers were included in the survey. Data was collected by using a pretested interviewer administered structured questionnaire. The questionnaire was prepared by including socio-demographic variables and variables of maternal health service utilization factors. Data was entered using Epi-data version 1.4.4.0 and exported to SPSS version 20 for analysis. Bivariate and multiple logistic regressions were applied to identify candidate and predictor variables respectively.Only 38% of study participants delivered the index child at health facility. Husband's educational status, wealth index, average distance from nearest health facility, wanted pregnancy, agreement to follow post-natal care, problem faced during delivery, birth order, preference of health professional for ante-natal care and maternity care were predictors of institutional delivery.The use of institutional delivery service is

  8. Evaluation of crack arrest fracture toughness of parent plate, weld metal and heat affected zone of BIS 812 EMA ship plate steel

    Science.gov (United States)

    Burch, I. A.

    1993-10-01

    The steel chosen for the pressure hull of the Collins class submarine has undergone evaluation to compare the crack arrest fracture toughness, K(Ia), of the parent plate with that of weld metal and heat affected zone. The tests were conducted over a range of subzero temperatures on specimens slightly outside the ASTM standard test method specimen configuration. Shallow face grooved specimens were used to vary the propagating crack velocity from that of non face grooved specimens and determine if K(Ia), is sensitive to changes in crack velocity. The weld metal, heat affected zone (HAZ), and parent plate were assessed to determine if the welding process had a deleterious effect on the crack arrest properties of this particular steel. Tests on each of these regions revealed that, for the combination of parent plate, welding procedure and consumables, no adverse effect on crack arrest properties was encountered. Crack arrest fracture toughness of the weld metal and HAZ was superior to that of the parent plate at comparable temperatures.

  9. Segregation behavior of phosphorus in the heat-affected zone of an A533B/A182 dissimilar weld joint before and after simulated thermal aging

    International Nuclear Information System (INIS)

    Highlights: • Impacts of aging on P segregation in actual heat-affected zone were examined by 3D-APT. • Non-equilibrium segregation of P dominated in subsequent cooling after welding. • Equilibrium segregation of P prevailed in step-cooling heat treatment. • High enrichment of P at grain/packet boundaries occurred in CGHAZ and ICCGHAZ. • Level of P enrichment at precipitate/matrix interface seemed species-dependent. - Abstract: The segregation behavior of phosphorus (P) in the heat-affected zone (HAZ) of an A533B/A182 dissimilar weld joint before and after step cooling was investigated with atom probe tomography. At grain/packet boundaries, the final P segregation level consisted of non-equilibrium segregation that occurred during cooling after welding and post-weld heat treatment (PWHT) and equilibrium segregation that occurred during step cooling. In both processes, higher P coverage was observed in the coarse-grained and intercritically reheated coarse-grained HAZ than in the fine-grained HAZ and base material. The cooling after welding and PWHT seemed to have a pronounced impact on P segregation in the subsequent aging process. In addition, P segregation also occurred at the precipitate/matrix interfaces of cementite, Mo2C and Al–Si rich precipitates. The evolution of P coverage at these two types of sites suggested increasing risks of embrittlement with an increase in aging time

  10. Aespoe Hard Rock Laboratory. Studies of factors that affect and controls the Excavation Damaged/Disturbed Zone

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Martin; Baeckstroem, Ann; Quanhong Feng (AaF - Berg och Maetteknik, Stockholm (Sweden)); Berglund, Johan (Vattenfall Power Consultant, Stockholm (Sweden)); Johansson, Malin; Mas Ivars, Diego (Itasca Geomekanik AB, Solna (Sweden)); Olsson, Mats (SweBefo, Stockholm (Sweden))

    2009-07-15

    A tunnel was developed at the Aespoe Hard Rock Laboratory (HRL) in 2003 purposely for a large in-situ rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). The tunnel had a large height/width ratio with a circular floor, primarily to control the stress situation around the tunnel and concentrate the stresses under the floor. An extensive set of data for understanding the Excavation Damaged Zone (EDZ) was collected within section 47 of the tunnel. It consist of the blast design, blast sequences, convergence measurements during excavation, geological mapping of tunnel and cores, 3D-laser scanning of the tunnel geometry etc. Furthermore, in 2006, ultrasonic measurements along eight boreholes were carried out in order to estimate the extent of the EDZ in the tunnel. The collection of all these different information provides an opportunity to evaluate the mechanical damages caused by the excavation work. The overall aim with this project is to give feed-back to future planning of tunnelling on issues of importance for requirements with respect to minimising the EDZ in crystalline rock from the drill and blast method. A combination of the mapped geological features (tunnel and cores) and the geometry of the blasted tunnel obtained from the 3D-laser scanning were used to build a 3D model of the geology with emphasis on the geometry of the natural fractures. The rock mechanic response to the tunnelling was evaluated in a numerical model including the as-built geometry in combination with the 3D model of the geology. The modelling of the rock mechanical processes of importance for the EDZ could be calibrated against actual measurements. From observed changes in the ultrasonic wave velocity along the boreholes it was found that the locations of the velocity changes corresponded well with the location of the mapped fractures in the drill cores. This indicates that EDZ can be detected using the ultrasonic method with high accuracy. Furthermore, the

  11. Why person affected by leprosy did not look after their plantar ulcer? Experience from Pakokku zone, Myanmar.

    Science.gov (United States)

    Win, Le Le; Shwe, San; Maw, Win; Ishida, Yutaka; Myint, Kyaw; Mar, Kyi Kyi; Min, Thandar; Oo, Phyo Min; Khine, Aye Win

    2010-09-01

    A cross-sectional study was carried out to identify methods of caring plantar ulcers in leprosy patients and the underlying causes of poor plantar ulcer care during January and February 2008. This was conducted in Pakokku zone as it was one of the "9 selected townships of the Disabilities survey, i.e., Basic Health Staff project 2003/4", which was funded by Japan International Cooperation Agency. After getting consent, all available leprosy cases, i.e., 101 cases with foot disability grade 2 were interviewed with the pre-tested questionnaire. Among 101 cases, 13 cases who took care of their ulcer poorly and 20 who did none of the recommended measures were recruited for in-depth interview (IDI). The subjects were largely old people, males and people with no marriage partner. The majority had earned money by doing sedentary job. Prolongation of ulcers was observed in 78 cases. Most had been suffering from ulcers for years. When asking face-to-face interview, all the recommended care measures were not reported. Among these recommended measures, a large number of respondents reported about soaking measure. However, these reported measures were contradicted to the preventive methods which they disclosed in IDI. Plantar ulcer care seemed to be an individualised practice. The individual ways of performing were related to their view of ulcer, the environment, and occupation, and custom, communication with family and health staff. The findings identified the actual practice of plantar ulcer care in study areas. It is suggested that the current performance of planar ulcer care is inadequate and more attention should be given to achieve the target set by the programme as a recommendation. PMID:20857653

  12. Differences in Water Vapor Radiative Transfer among 1D Models Can Significantly Affect the Inner Edge of the Habitable Zone

    Science.gov (United States)

    Yang, Jun; Leconte, Jérémy; Wolf, Eric T.; Goldblatt, Colin; Feldl, Nicole; Merlis, Timothy; Wang, Yuwei; Koll, Daniel D. B.; Ding, Feng; Forget, François; Abbot, Dorian S.

    2016-08-01

    An accurate estimate of the inner edge of the habitable zone is critical for determining which exoplanets are potentially habitable and for designing future telescopes to observe them. Here, we explore differences in estimating the inner edge among seven one-dimensional radiative transfer models: two line-by-line codes (SMART and LBLRTM) as well as five band codes (CAM3, CAM4_Wolf, LMDG, SBDART, and AM2) that are currently being used in global climate models. We compare radiative fluxes and spectra in clear-sky conditions around G and M stars, with fixed moist adiabatic profiles for surface temperatures from 250 to 360 K. We find that divergences among the models arise mainly from large uncertainties in water vapor absorption in the window region (10 μm) and in the region between 0.2 and 1.5 μm. Differences in outgoing longwave radiation increase with surface temperature and reach 10–20 W m‑2 differences in shortwave reach up to 60 W m‑2, especially at the surface and in the troposphere, and are larger for an M-dwarf spectrum than a solar spectrum. Differences between the two line-by-line models are significant, although smaller than among the band models. Our results imply that the uncertainty in estimating the insolation threshold of the inner edge (the runaway greenhouse limit) due only to clear-sky radiative transfer is ≈10% of modern Earth’s solar constant (i.e., ≈34 W m‑2 in global mean) among band models and ≈3% between the two line-by-line models. These comparisons show that future work is needed that focuses on improving water vapor absorption coefficients in both shortwave and longwave, as well as on increasing the resolution of stellar spectra in broadband models.

  13. Natural Radiation for Identification and Evaluation of Risk Zones for Affectation of Activated Faults in Aquifer Overexploited.

    Science.gov (United States)

    Ramos-Leal, J.; Lopez-Loera, H.; Carbajal-Perez, N.

    2007-05-01

    In basins as Mexico, Michoacán, Guanajuato, Queretaro, Aguascalientes and San Luis Potosi, the existence of faults and fractures have affected the urban infrastructure, lines of conduction of drinkable water, pipelines, etc., that when not being identified and considered, they don't reflect the real impact that these cause also to the aquifer system, modifying the permeability of the means and in occasions they work as preferential conduits that communicate hydraulically potentially to the aquifer with substances pollutants (metals, fertilizers, hydrocarbons, waste waters, etc.) located in the surface. In the Valley of San Luis Potosi, Villa of Reyes, Arista, Ahualulco and recently The Huizache-Matehuala is being strongly affected by faulting and supposedly due cracking to subsidence, however, the regional tectonic could also be the origin of this phenomenon. To know the origin of the faults and affectation to the vulnerability of the aquifer few works they have been carried out in the area. A preliminary analysis indicates that it is possible that a tectonic component is affecting the area and that the vulnerability of the aquifer in that area you this increasing. Before such a situation, it is necessary to carry out the isotopic study of the same one, for this way to know among other things, isotopic characterization, recharge places and addresses of flow of the groundwater; quality of waters and the behavior hydrochemistry with relationship to the faults. High radon values were measured in San Luis Potosi Valley, the natural source of radon could be the riolites and however, these are located to almost a once thousand meters deep for what the migration of the gas is not very probable. The anomalies radiometrics was not correlation with the faults in this case. In some areas like the Valley of Celaya, the origin of the structures and the tectonic activity in the area was confirmed, identifying the structural arrangement of the faulting, the space relationships

  14. Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae.

    Science.gov (United States)

    de Waal, C; Rodger, J G; Anderson, B; Ellis, A G

    2014-05-01

    Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges. PMID:24735437

  15. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    International Nuclear Information System (INIS)

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ13C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m−2⋅y−1. Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the terrestrial

  16. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Junchao [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Thanh, E-mail: bswang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Han, Shanlong [Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Pu; Zhang, Qinghua; Jiang, Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ{sup 13}C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m{sup −2}⋅y{sup −1}. Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the

  17. Long-term sediment yield from small catchment in southern Brazil affected by land use and soil management changes.

    Science.gov (United States)

    Gomes Minella, Jean Paolo; Henrique Merten, Gustavo; Alessandra Peixoto de Barros, Claudia; Dalbianco, Leandro; Ramon, Rafael; Schlesner, Alexandre

    2015-04-01

    Soil erosion and sediment yield are the main cause of soil degradation in Brazil. Despite this, there is a lack of information about the effects of the soil management on the hydrology and sediment yield at catchment scale. This study aimed to investigate the long-term relationship between the land use and sediment yield in a small catchment with significant changes in soil management, and its impacts on soil erosion and sediment yield. To account the anthropogenic and climatic effects on sediment yield were monitored precipitation, stream flow and suspended sediment concentration during thirteen years (2002 and 2014) at 10 minutes interval and the changes that occurred each year in the land use and soil management. Despite the influence of climate on the sediment yield, the results clearly show three distinct periods affected by the land use and soil management changes during this this period. In the first four years (2002-2004) the predominant land use was the tobacco with traditional soil management, where the soils are plough every year and without winter cover crop. In this period the sediment yield reached the order of 160 t.ha-1.y-1. In the period of 2005-2009, a soil conservation program introduced the adoption of minimum tillage in the catchment and the sediment yield decrease to 70 t.ha-1.y-1. In the last period (2010-2014) there was a partial return to the traditional soil management practices with an increase trend in sediment yield. However, there was also an increase in reforestation areas with positive effect in reducing erosion and sediment yield. The magnitude order of sediment yield in this period was 100 t.ha-1.y-1. The long term sediment yield data was able to demonstrate the impact of the improved management practices in reducing soil erosion and sediment yield. The results allowed a good understanding of the changing sediment dynamics and soil erosion at catchment scale.

  18. Factors affecting the reproductive performance of Bunaji cattle under different pastoral management systems in the Guinea savanna zone of Nigeria

    International Nuclear Information System (INIS)

    The effects of management on the productivity of Bunaji cattle were investigated on 6 farms using 38 post-partum cows and 8 heifers. General information obtained on management of the farms indicated differences in managements practices between farms. The screening of the animals in the various farms for blood and endo-parasites showed that some of the farms had problems of helminthiasis and fascioliasis. Uterine involution was complete within 25 days of calving in all post-partum cows. Intervals from calving to ovulation and conception were different between farms. The conception rates for all farms over a period of 730 days ranged from 60 to 100%. A higher percentage of heifers on farm A reached puberty at an earlier age than those in farm B. It was concluded that management affects reproductive performance and thus productivity of Bunaji cattle, with nutrition and disease being the major contributing factors. (author). 10 refs, 7 tabs

  19. Influence of Column Axial Load and Heat Affected Zone on the Strength of Aluminium Column Web in Tension

    Directory of Open Access Journals (Sweden)

    Gianfranco De Matteis

    2014-05-01

    Full Text Available The component method for aluminium joints has been recently introduced in some codes and guidelines. Nevertheless, it is still in need of some development and improvement, as in some cases it was obtained by adapting the existing formulations that are valid for steel. The current paper presents the main outcomes of a parametric analysis carried out by means of finite element (FE numerical models for determining the influence of both column axial load and heat affected zone—in the case of welded details—on the structural response of the column web in a tension component. The proposed study integrates previous research carried out by the authors, where the influence of the assumed alloy was investigated and interpreted by corrective parameters expressed as a function of both the material strain hardening and ductility.

  20. Dynamics and Preservation Potential of Subduction Complexes in Continental Sutures: A Case Study from the Sedimentary-Marix Mélange of the Indus-Yarlung Suture Zone in Southern Tibet

    Science.gov (United States)

    Metcalf, K.; Kapp, P. A.; Orme, D. A.

    2015-12-01

    Intra-continental sutures are the geologic record of ancient subduction zones. Subduction complexes are a useful record of ancient continental collisions because they preserve sediments and/or blocks from units which have since eroded and are the first point of contact during collision. The India-Asia collision is one of the most-studied collisional orogens, but how much of the original subduction complex is preserved and what we can determine about the dynamics of the ancient subduction zone along the southern margin of Asia is poorly understood. Compared to other subduction complexes around the world, the complex preserved in the Indus Yarlung Suture Zone (IYSZ) of southern Tibet is anomalous. Blueschist facies metamorphism, a prominent mineral assemblage along intra-continental suture zones, is common in the northwest Himalaya, but not found along the central segment of the IYSZ. Most of the subduction complex is greenschist facies, inconsistent with the geotherm for a subduction zone. We present a metamorphic history for the greenschist facies rocks to reconcile this contradiction. A deep forearc basin (~5-8 km) developed during the Cretaceous, requiring an accretionary subduction zone, a topographic or structural outer forearc high behind which to trap sediment, and/or basal subduction erosion. The preserved subduction complex is almost entirely tectonic sedimentary-matrix mélange with minor outcrops of overlying turbidites. We present evidence from detrital zircon U-Pb geochronology of sandstones that indicate along-strike variability in the provenance of the sedimentary-matrix mélange. For example, both lower and upper plate material are present near the town of Ngamring, while regions along-strike to the west contain little to no upper plate material. The blocks in the sedimentary-matrix mélange are well-mixed throughout kilometers of exposed width. Sandstone blocks of Tethyan affinity, which could have entered the trench only at the onset of collision

  1. Transport accidents among children and adolescents at the emergency service of a teaching hospital in the southern zone of the city of São Paulo☆☆☆

    Science.gov (United States)

    Gorios, Carlos; de Souza, Renata Maia; Gerolla, Viviane; Maso, Bruno; Rodrigues, Cintia Leci; Armond, Jane de Eston

    2014-01-01

    Objective to describe the victim profile and circumstances of transport accidents involving children and adolescents who were attended at a teaching hospital in the southern zone of the city of São Paulo. Methods this was an individual observational case series study among patients up to the age of 19 years who were attended at a hospital in the southern zone of the city of São Paulo, state of São Paulo, Brazil, due to traffic accidents. The files notifying suspected or confirmed cases of violence and accidents (SIVVA files) covering January to December 2012 were analyzed. Results among the 149 cases notified, 64.4% related to males and 35.6% to females. The transport accidents were predominantly among males, irrespective of age. The main injury diagnoses were superficial head trauma (24.8%) followed by multiple non-specified trauma (36.4%), in both sexes. Conclusion transport accidents among children and adolescents occurred more often among males. The main transport accidents among the children and adolescents attended as emergency cases were caused by motor vehicles and motorcycles. Among the accident victims, the largest proportion was attended because of being run over. PMID:26229833

  2. Riparian Zones, Protected River corridors in 9 county region in South Georgia, Published in 1999, 1:7200 (1in=600ft) scale, Southern Georgia Regional Commission.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Riparian Zones dataset, published at 1:7200 (1in=600ft) scale, was produced all or in part from Other information as of 1999. It is described as 'Protected...

  3. X-ray diffraction analysis and metal physics modeling of static strain aging and thermal dislocation recovery in the mechanically affected zone of surface finished hardened steel

    Energy Technology Data Exchange (ETDEWEB)

    Gegner, Juergen [SKF GmbH, Dept. of Material Physics, Schweinfurt (Germany)

    2009-07-01

    After heat treatment, finish machining of the hardened steel represents the last manufacturing step of machine elements. The practically most important operation of grinding is applied to achieve edge zone compressive residual stresses, best surface quality and dimensional accuracy. Metal removal involves high plastic deformation work. Glide and intersection processes raise the density and produce lower energy substructures of dislocations. The temperature and time behavior of post-machining thermal treatment is analyzed on ground and honed martensitic SAE 52100 rolling bearing steel. Microstructure stabilization is reflected in a large XRD line width decrease on the surface. The kinetics is modeled by rate-controlling carbide dissolution as the carbon source for Cottrell-type segregation at dislocations. This static strain aging is verified by the formation of a slight white etching surface layer. The metal physics model is extended to also consider superimposed thermal dislocation recovery. Both effects are separable. In rolling contact fatigue tests under mixed friction running conditions, air reheating of the samples below the tempering temperature, which avoids hardness loss, leads to a significant lifetime increase. Thermal post-treatment after cold working results in similar changes of the XRD line width in the larger mechanically affected edge zone.

  4. 地形和乔木结构对热带北缘与南亚热带过渡带林下植被分布的影响%Effects of Topography and Tree Structure on the Distribution Patterns of Understory Plants in the Transitional Area between China’s Southern Subtropical Zone and the Northern Edge of the Tropical Zone

    Institute of Scientific and Technical Information of China (English)

    张昌顺; 谢高地; 陈龙; 裴厦; 范娜

    2012-01-01

    地处澜沧江下游热带北缘与南亚热带过渡带的糯扎渡自然保护区,是中国南亚热带森林生态系统类型的自然保护区。本文以糯扎渡自然保护区主要森林类型为研究对象,利用相关分析和典范对应分析(CCA)研究了地形和乔木结构对该区域林下不同生长型地表植物生长与分布格局的影响。结果表明:地形和乔木结构对热带北缘与南亚热带过渡区林下3种生长型地表植物(灌木、层间植物和草本)的生长和分布格局的影响显著,其中地形和乔木结构对灌木生长的作用大于草本,除坡度和乔木密度外,其余指标对灌木盖度或灌木高度的影响达显著水平。地形和乔木结构对林下不同生长型植被种类组成和结构的影响是不同的,按影响程度大小,影响灌木层种类组成和结构的主要因素依次为胸高断面积、树高、乔木种数和香浓维纳指数,对于层间植物,则依次为胸高断面积、树高、海拔、乔木种数和乔木盖度,对于草本层,则依次为胸高断面积、乔木种数、坡向和树高。就整体而言,乔木结构对林下植被结构和种类的影响大于与地形因子,地形因子中,仅海拔和坡向分别对林下层间植物和草本分布的影响显著,说明乔木结构是小尺度研究中影响林下水热条件的主要因子,但海拔和坡向对它们也有较大的影响。%Nuozadu Nature Reserve located in the transitional area between China’s southern subtropical zone and the noruthern edge of the tropical zone is a forest ecosystems nature reserve of 216.8 km2 in south of Yunnan Province. Much of the environmental variability controlling the spatial patterns of ground cover might be attributed to topographical variations and their influence on soil-light-water distribution, and tree structure such as canopy vegetation and canopy gaps, which, affecting growth and mortality of understory plants. In this paper, Tto study

  5. Estimation of the most influential factors on the laser cutting process heat affected zone (HAZ) by adaptive neuro-fuzzy technique

    Science.gov (United States)

    Petković, Dalibor; Nikolić, Vlastimir; Milovančević, Miloš; Lazov, Lyubomir

    2016-07-01

    Heat affected zone (HAZ) of the laser cutting process may be developed on the basis on combination of different factors. In this investigation was analyzed the HAZ forecasting based on the different laser cutting parameters. The main aim in this article was to analyze the influence of three inputs on the HAZ of the laser cutting process. The method of ANFIS (adaptive neuro fuzzy inference system) was applied to the data in order to select the most influential factors for HAZ forecasting. Three inputs are considered: laser power, cutting speed and gas pressure. According the results the cutting speed has the highest influence on the HAZ forecasting (RMSE: 0.0553). Gas pressure has the smallest influence on the HAZ forecasting (RMSE: 0.0801). The results can be used in order to simplify HAZ prediction and analyzing.

  6. Mechanisms and modeling of cleavage fracture in simulated heat-affected zone microstructures of a high-strength low alloy steel

    Science.gov (United States)

    Lambert-Perlade, A.; Sturel, T.; Gourgues, A. F.; Besson, J.; Pineau, A.

    2004-03-01

    The effect of the welding cycle on the fracture toughness properties of high-strength low alloy (HSLA) steels is examined by means of thermal simulation of heat-affected zone (HAZ) microstructures. Tensile tests on notched bars and fracture toughness tests at various temperatures are performed together with fracture surface observations and cross-sectional analyses. The influence of martensite-austenite (M-A) constituents and of “crystallographic” bainite packets on cleavage fracture micromechanisms is, thus, evidenced as a function of temperature. Three weakest-link probabilistic models (the “Master-curve” (MC) approach, the Beremin model, and a “double-barrier” (DB) model) are applied to account for the ductile-to-brittle transition (DBT) fracture toughness curve. Some analogy, but also differences, are found between the MC approach and the Beremin model. The DB model, having nonfitted, physically based scatter parameters, is applied to the martensite-containing HAZ microstructures and gives promising results.

  7. Effect of Mg Content on the Microstructure and Toughness of Heat-Affected Zone of Steel Plate after High Heat Input Welding

    Science.gov (United States)

    Xu, Long-Yun; Yang, Jian; Wang, Rui-Zhi; Wang, Yu-Nan; Wang, Wan-Lin

    2016-07-01

    The effect of Mg content on the microstructure and toughness of the heat-affected zone (HAZ) of steel plates after high heat input welding was investigated by means of welding thermal simulation test and in situ observation through high-temperature laser scanning confocal microscopy. It was found that with the increase of Mg content in the steel, the former austenite grain sizes were greatly decreased and the mainly microstructural constituents in HAZ were changed from the brittle constituents of Widmanstätten ferrite, ferrite side plate and upper bainite to the ductile constituents of intragranular acicular ferrite and polygonal ferrite. The proportion of grain boundary ferrite was decreased greatly with the further addition of Mg from 27 to 99 ppm. As a result, the HAZ toughness after welding with heat input of 400 kJ cm-1 is increased with increasing Mg content in the steel plate.

  8. Design requirements for ERD in diffusion-dominated media: how do injection interval, bioactive zones and reaction kinetics affect remediation performance?

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Lemming, Gitte; Manoli, Gabriele;

    transport processes, and this affects the timeframes for the remediation. Due to the limited ERD applications and the complex transport and reactive processes occurring in low-permeability media, design guidelines are currently not available for ERD in such settings, and remediation performance assessments......Enhanced Reductive Dechlorination (ERD) has been successfully used in high permeability media, such as sand aquifers, and is considered to be a promising technology for low permeability settings. Pilot and full-scale applications of ERD at several sites in Denmark have shown that the main challenge...... are limited. The objective of this study is to combine existing knowledge from several sites with numerical modeling to assess the effect of the injection interval, development of bioactive zones and reaction kinetics on the remediation efficiency for ERD in diffusion-dominated media. A numerical model...

  9. Geoelectrical behavior of a Fault Zone: the meaning of the electrical resistivity of metric-scale segments of the Liquiñe-Ofqui and the Arc-oblique Long-lived Fault Systems, Southern Andes

    Science.gov (United States)

    Roquer, T.; Arancibia, G.; Yanez, G. A.; Estay, N.; Rowland, J. V.; Figueroa, R.; Iturrieta, P. C.

    2015-12-01

    The geoelectrical behavior of blind fault zones has been studied by different authors at decametric-to-kilometric scales, and inferred to reveal the dimensions of the main structural domains of a fault zone (core vs. damage zone). However, there is still a lack in the application of electrical methods in exposed fault zones, despite the importance of validating the inferences based on electrical measurements with direct geologic observation. In this study we correlate the results of structural mapping and geoelectrical measurements in two metric-scale, very well exposed segments of the Liquiñe-Ofqui Fault System (LOFS) and the Arc-oblique Long-lived Fault System (ALFS), Southern Andes. The LOFS is an active dextral and dextral-normal ca. 1200-km-long Cenozoic intra-arc structure that strikes NNE to NE. Although the LOFS and the ALFS cross-cut each other, the ALFS is an apparently older basement NW-striking fault system where mainly sinistral movement is recorded. Two 22-m-long transects were mapped revealing in both examples a simple core and an assymetric damage zone with more frequency of fractures in the hanging wall than in the footwall. The LOFS outcrop showed a WNW-striking, 65°S-dipping core; the ALFS, a NW-striking, 60°SW-dipping core. A 2D direct-current electrical survey was made at each locality, orthogonal to the respective strike of the core. The field installation of the electrical survey used two electrode configurations for each outcrop: (1) electrodes were put in a vertical wall of rock, which gives a resistivity profile in plan view; and (2) electrodes were put in the ground, which gives a cross-section resistivity profile. The combined structural and electrical results suggest that: (1) it is possible to discriminate the geoelectrical response of the main metric-scale structural domains: the core and the fractured damage zones are relative conductors (20-200 ohm-m), whereas the less fractured damage zones are relative resistive volumes (500

  10. Unveiling the Si cycle using isotopes in an iron fertilized zone of the Southern Ocean: from mixed layer supply to export

    OpenAIRE

    Closset, Ivia; Cardinal, Damien; Rembauville, Mathieu; Thil, François; Blain, Stéphane

    2016-01-01

    A massive diatom-bloom is observed annually in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). In this study, silicon isotopic signatures (δ30Si) of silicic acid (DSi) and suspended biogenic silica (BSi) were investigated in the whole water column with an unprecedented spatial resolution in this region, during the KEOPS-2 experiment (spring 2011). We use δ30Si measurements to track the silicon sources that fuel the bloom, and investigate the seasonal evol...

  11. Distribution patterns of natural radioactivity and delineation of anomalous radioactive zones using in situ radiation observations in Southern Tamil Nadu, India

    Energy Technology Data Exchange (ETDEWEB)

    Singh, H.N. [Department of Geophysics, Banaras Hindu University, Varanasi 221 005 (India)]. E-mail: hridaynarain.singh@gmail.com; Shanker, D. [Department of Earthquake Engineering, Indian Institute of Technology, Roorkee, Uttaranchal (India)]. E-mail: dayasfeq@iitr.ernet.in; Neelakandan, V.N. [Centre for Earth Science Studies, P.B. No. 7250, Akkulam, Trivandrum 695 031 (India)]. E-mail: neelakandanvn@gmail.com; Singh, V.P. [Department of Geophysics, Banaras Hindu University, Varanasi 221 005 (India)

    2007-03-06

    In situ radiation measurements in the beach sectors and adjacent hinterlands and along rivers in the interiors of southern peninsular India were carried out using a portable radiation survey meter. A very high intrinsic anomalous radioactivity >26 {mu}Gy/h has been observed in the hinterlands within a fresh quarry and weathered boulders in the syenite rock body around Puttetti in the western Kanyakumari district of southern Tamil Nadu. Over the weathered hillocks in the hinterlands adjacent to the coast around Inayam, Kurumpanai and Midalam, the in situ radiation measurements have also exhibited high radioactivity ranging from 4 to 22 {mu}Gy/h which is significantly higher than the radiation exposure rates (RER) observed along the beach sectors at various locations from Chavara to Tuticorin (1-14 {mu}Gy/h). The observed radiation levels are presumably the highest concentration in southern India and it is the first time that such a high intrinsic radiogenic source in the hinterlands is reported in southwest coast of India. It is also observed based on the laboratory analysis of samples and in situ radiation data that the rivers/channels in this region contain insignificant level of radioactivity concentration and hence they do not contribute much to the placer deposits on the beaches. The placer deposits associated with significant RER (both in situ observations as well as laboratory estimates from samples) in the beach sectors from Kadiapattanam to Inayam are inferred to be derived through the country rocks/weathered hillocks in the immediate hinterlands.

  12. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    Science.gov (United States)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-06-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  13. Minimization of heat-affected zone size in welded ultra-fine grained steel under cooling by liquid nitrogen during laser welding

    International Nuclear Information System (INIS)

    Ultra-fine grained steel (UFGS) with an average grain size of less than 1 μm has been developed and is expected to demonstrate superior mechanical and chemical properties. However, its welded heat-affected zones, HAZ, substantially affecting the strength of a welded joint, will be easily softened after welding. Therefore, minimization of UFGS's HAZ size during laser welding was carried out using the cooling conductor liquid nitrogen. It was found that a shielding gas, with adequate flow rate for the liquid nitrogen depth, was used to remove nitrogen from the area of laser beam irradiation to stabilize the weld bead. Also, the YAG laser system was mainly used because it has a lower temperature, which results in a decreased occurrence of pits and blowholes, of laser induced plasma or plume. HAZ size minimization strongly depends on the initial plate temperature. Reduced initial plate temperature shrinks the specific heated temperature range in which softening occurs. However, under room temperature, due possibly to decreasing thermal conductivity that prevents heat removal from HAZ, the benefit of reducing the initial plate temperature is limited. The optimal initial temperature to minimize the HAZ size was found to be 123 K

  14. Punctuated Neogene tectonics and stratigraphy of the African-Iberian plate-boundary zone: concurrent development of Betic-Rif basins (southern Spain, northern Morocco)

    NARCIS (Netherlands)

    Sissingh, W.

    2008-01-01

    This paper integrates the sequence stratigraphic and tectonic data related to the Neogene geodynamic and palaeogeographic development of the African-Iberian plate boundary zone between Spain and Morocco. Though the dating of individual tectonostratigraphic sequences and their delimiting sequence bou

  15. Upper plate deformation and seismic barrier in front of Nazca subduction zone : the Chololo Fault System and active tectonics along the Coastal Cordillera, southern Peru

    OpenAIRE

    Audin, Laurence; Lacan, P.; Tavera, H.; Bondoux, Francis

    2008-01-01

    The South America plate boundary is one of the most active subduction zone. The recent Mw=8.4 Arequipa 2001 earthquake ruptured the subduction plane toward the south over 400 km and stopped abruptly on the Ilo Peninsula. In this exact region, the subduction seismic crisis induced the reactivation of continental fault systems in the coastal area. We studied the main reactivated fault system that trends perpendicular to the trench by detailed mapping of fault related-geomorphic features. Also, ...

  16. Extracellular enzyme activities in a tropical mountain rainforest region of southern Ecuador affected by low soil P status and land-use change

    Science.gov (United States)

    Tischer, Alexander; Blagodatskaya, Evgenia; Ute, Hamer

    2014-05-01

    Little is known about the enzymatic response of microorganisms in soils having a low P status and being subjected to global change phenomena, such as forest disturbance and land-use change. Along a land-use sequence (natural forest - young pasture - old pasture - abandoned pasture - shrubland) in the Andes of southern Ecuador mineral topsoils of Cambisols / Umbrisols were investigated. We tested whether the activities of the six hydrolytic enzymes (cellobiohydrolase, β-glucosidase, N-acetylglucosaminidase, α-glucosidase, xylanase, acid phosphomonoesterase) were affected by nutrient status and land-use induced alterations in soil pH (pHH2O from 3.7 to 5.2), resource quantity and quality (e.g. a SOC:N:P ratio from 182:13:1 to 1050:38:1) and microbial community structure (as monitored by phospholipid fatty acids). Microbial production of acid phosphatase responded to the low P status of the sites by a higher investment in the acquisition of P compared to C. We determined three major drivers of enzyme activities: 1.) Microbial demand for P regulated the production of acid phosphatase, provided that N and C were available. At the natural forest site the two-fold higher specific activity of acid phosphatase pointed to a high microbial P-demand, whereas the production of acid phosphatase was constrained by the availability of N and DOC after pasture abandonment. 2.) Microbial biomass that was controlled by pH and resource availability (total soil N (organic and inorganic N), organic P (Bray-fraction)) was the main driver for cellobiohydrolase, β-glucosidase and N-acetylglucosaminidase activities. 3.) Substrate induction due to increased litter inputs of herbaceous plant species seemed to regulate α-glucosidase and xylanase activities during secondary succession. In contrast, alterations in the abundance of microbial groups affected the variation in extracellular enzyme activities only marginally. At the level of broadly defined microbial groups (PLFA), our results

  17. Precipitation Behavior in the Heat-Affected Zone of Boron-Added 9Cr-3W-3Co Steel During Post-Weld Heat Treatment and Creep Deformation

    Science.gov (United States)

    Liu, Yuan; Tsukamoto, Susumu; Sawada, Kota; Tabuchi, Masaaki; Abe, Fujio

    2015-05-01

    In the previous paper, we demonstrated that the addition of boron was effective in preventing type IV failure due to suppression of grain refinement in the heat-affected zone at the peak temperature of around AC3 (AC3 HAZ). However, some fine prior austenite grains (PAGs) still remained around the coarse PAG boundaries, and these fine PAGs may affect the creep property of the welded joint. In the present study, the effect of these fine PAGs on the creep property of the boron-added 9Cr-3Co-3W steel (B steel) Ac3 HAZ is investigated. Different heat treatments are carried out on B steel base metal to form different Ac3 HAZ-simulated microstructures of coarse PAG with and without fine PAGs. Ac3 HAZ microstructure shows that a lot of M23C6 carbides are formed at the block boundary in the interior of coarse PAG. On the other hand, few M23C6 carbides are formed at the fine PAG boundaries, but a number of μ phases (W6Fe7 type) cover the boundary. The formation of μ phase retards the recovery of dislocation at the fine PAG boundary and contributes to stabilizing the microstructure in the primary and transient creep regions. The μ phase transforms to the Laves phase during creep. As the growth rate of Laves phase is higher than that of M23C6 carbides during creep, the creep strength of fine PAG boundary, which is strengthened only by Laves phase, becomes a little bit lower than the other boundaries strengthened by M23C6 carbides after long-term creep. The mismatch of creep strength between the fine PAG boundary and the matrix should be taken into account to attain an excellent long-term creep property of the B steel welded joint.

  18. Will changes in root-zone temperature in boreal spring affect recovery of photosynthesis in Picea mariana and Populus tremuloides in a future climate?

    Science.gov (United States)

    Fréchette, Emmanuelle; Ensminger, Ingo; Bergeron, Yves; Gessler, Arthur; Berninger, Frank

    2011-11-01

    Future climate will alter the soil cover of mosses and snow depths in the boreal forests of eastern Canada. In field manipulation experiments, we assessed the effects of varying moss and snow depths on the physiology of black spruce (Picea -mariana (Mill.) B.S.P.) and trembling aspen (Populus tremuloides Michx.) in the boreal black spruce forest of western Québec. For 1 year, naturally regenerated 10-year-old spruce and aspen were grown with one of the following treatments: additional N fertilization, addition of sphagnum moss cover, removal of mosses, delayed soil thawing through snow and hay addition, or accelerated soil thawing through springtime snow removal. Treatments that involved the addition of insulating moss or snow in the spring caused lower soil temperature, while removing moss and snow in the spring caused elevated soil temperature and thus had a warming effect. Soil warming treatments were associated with greater temperature variability. Additional soil cover, whether moss or snow, increased the rate of photosynthetic recovery in the spring. Moss and snow removal, on the other hand, had the opposite effect and lowered photosynthetic activity, especially in spruce. Maximal electron transport rate (ETR(max)) was, for spruce, 39.5% lower after moss removal than with moss addition, and 16.3% lower with accelerated thawing than with delayed thawing. Impaired photosynthetic recovery in the absence of insulating moss or snow covers was associated with lower foliar N concentrations. Both species were affected in that way, but trembling aspen generally reacted less strongly to all treatments. Our results indicate that a clear negative response of black spruce to changes in root-zone temperature should be anticipated in a future climate. Reduced moss cover and snow depth could adversely affect the photosynthetic capacities of black spruce, while having only minor effects on trembling aspen. PMID:22021010

  19. Effect of inter-critically reheating temperature on microstructure and properties of simulated inter-critically reheated coarse grained heat affected zone in X70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhixiong, E-mail: zhixiongzhu@gmail.com [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Kuzmikova, Lenka; Li, Huijun [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Barbaro, Frank [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); CBMM Technology Suisse, 14, Rue du Rhone, Geneva 1204 (Switzerland)

    2014-05-01

    This study investigated the influence of the inter-critical reheating temperature on the microstructure and mechanical properties of a coarse grained heat affected zone (CGHAZ) in an API 5L grade X70 pipeline steel seam weld. A Gleeble 3500 thermo-mechanical simulator was employed to duplicate particular weld thermal cycles in order to accurately assess specific regions of the weld HAZ. Detailed microstructural analysis, including investigation of the martensite–austenite (M–A) constituent, was performed using optical microscope (OM), scanning electron microscope (SEM) and selective etching techniques. It is shown that the fracture toughness of the CGHAZ is significantly reduced following exposure to a subsequent inter-critical thermal cycle. Fracture toughness gradually improves as the inter-critical temperature is increased, but does not return to the value of the original CGHAZ due to the presence of isolated large M–A particles and coarse microstructure. Significance of M–A particles to the HAZ fracture toughness is first related to the location of particles along prior austenite grain boundaries, followed by the size of individual M–A particles.

  20. Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Mohammed, S. (Tennessee Univ., Knoxville, TN (USA). Welding Research and Engineering)

    1990-11-01

    The continuous cooling transformation behavior (CCT) and isothermal transformation (IT) behavior were determined for SA-508 and SA-533 materials for conditions pertaining to standard heat treatment and for the coarse-grained region of the heat-affected zone (HAZ). The resulting diagrams help to select welding conditions that produce the most favorable microconstituent for the development of optimum postweld heat treatment (PWHT) toughness levels. In the case of SA-508 and SA-533, martensite responds more favorably to PWHT than does bainite. Bainite is to be avoided for the optimum toughness characteristics of the HAZ. The reheat cracking tendency for both steels was evaluated by metallographic studies of simulated HAZ structures subjected to PWHT cycles and simultaneous restraint. Both SA-533, Grade B, Class 1, and SA-508, Class 2, cracked intergranularly. The stress rupture parameter (the product of the stress for a rupture life of 10 min and the corresponding reduction of area) calculated for both steels showed that SA-508, Class 2, was more susceptible to reheat cracking than SA-533, Grade B, Class 1. Cold cracking tests (Battelle Test and University of Tennessee modified hydrogen susceptibility test) indicated that a higher preheat temperature is required for SA-508, Class 2, to avoid cracking than is required for SA-533, Grade B, Class 1. Further, the Hydrogen Susceptibility Test showed that SA-508, Class 2, is more susceptible to hydrogen embrittlement than is SA-533, Grade B, Class 1.

  1. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs

  2. The use of supercomputer modelling of high-temperature failure in pipe weldments to optimize weld and heat affected zone materials property selection

    Science.gov (United States)

    Wang, Z. P.; Hayhurst, D. R.

    1994-07-01

    The creep deformation and damage evolution in a pipe weldment has been modeled by using the finite-element continuum damage mechanics (CDM) method. The finite-element CDM computer program DAMAGE XX has been adapted to run with increased speed on a Cray XMP/416 supercomputer. Run times are sufficiently short (20 min) to permit many parametric studies to be carried out on vessel lifetimes for different weld and heat affected zone (HAZ) materials. Finite-element mesh sensitivity was studied first in order to select a mesh capable of correctly predicting experimentally observed results using at least possible computer time. A study was then made of the effect on the lifetime of a butt welded vessel of each of the commomly measured material parameters for the weld and HAZ materials. Forty different ferritic steel welded vessels were analyzed for a constant internal pressure of 45.5 MPa at a temperature of 565 C; each vessel having the same parent pipe material but different weld and HAZ materials. A lifetime improvement has been demonstrated of 30% over that obtained for the initial materials property data. A methodology for weldment design has been established which uses supercomputer-based CDM analysis techniques; it is quick to use, provides accurate results, and is a viable design tool.

  3. Effect of inter-critically reheating temperature on microstructure and properties of simulated inter-critically reheated coarse grained heat affected zone in X70 steel

    International Nuclear Information System (INIS)

    This study investigated the influence of the inter-critical reheating temperature on the microstructure and mechanical properties of a coarse grained heat affected zone (CGHAZ) in an API 5L grade X70 pipeline steel seam weld. A Gleeble 3500 thermo-mechanical simulator was employed to duplicate particular weld thermal cycles in order to accurately assess specific regions of the weld HAZ. Detailed microstructural analysis, including investigation of the martensite–austenite (M–A) constituent, was performed using optical microscope (OM), scanning electron microscope (SEM) and selective etching techniques. It is shown that the fracture toughness of the CGHAZ is significantly reduced following exposure to a subsequent inter-critical thermal cycle. Fracture toughness gradually improves as the inter-critical temperature is increased, but does not return to the value of the original CGHAZ due to the presence of isolated large M–A particles and coarse microstructure. Significance of M–A particles to the HAZ fracture toughness is first related to the location of particles along prior austenite grain boundaries, followed by the size of individual M–A particles

  4. Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel

    Directory of Open Access Journals (Sweden)

    Węglowski M. St.

    2016-03-01

    Full Text Available In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.

  5. MICROSTRUCTURE AND INCLUSION CHARACTERIZATION IN THE SIMULATED COARSE-GRAIN HEAT AFFECTED ZONE WITH LARGE HEAT INPUT OF A Ti-Zr-MICROALLOYED HSLA STEEL

    Institute of Scientific and Technical Information of China (English)

    Y.T. Chen; X. Chen; Q.F. Ding; J. Zeng

    2005-01-01

    The microstructure and the characteristics of the inclusions embedded in ferrite matrix in simu lated coarse-grain heat affected zone (CGHAZ) of a Ti-Zr-treated high strength low alloy (HSLA) steel have been investigated. The microstructure of the simulated CGHAZ dominantly consisted of intragranular acicular ferrite (IAF) combining with a small amount of polygonal ferrite (PF), widmanstatten ferrite (WF), bainite ferrite (BF), pearlite and martensite-austenite (M-A) islands. The PF, WF and BF were generally observed at the prior austenite grain boundaries and the interlocking acicular ferrite was usually found intragranularly. It was found that the inclusions were composed of Ti2O3, ZrO2 Al2O3 locating at the center of the particles and MnS lying on the surface layer of the inclusions. The intragranular complex inclusions prornoted the acicular ferrite formation and the refinement of microstructure whilst those at prior austenite grain boundaries caused PF formation on the inclusions. The simulated CGHAZ con sisting of such complicated microstructure exhibited desired mechanical properties.

  6. Effects of Nb on microstructure and continuous cooling transformation of coarse grain heat-affected zone in 610 MPa class high-strength low-alloy structural steels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.Q. [Department of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)], E-mail: yingqiaozhang@yahoo.com.cn; Zhang, H.Q. [Department of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030 (China); Research Institute for Advanced Structural Steel, R and D Center, Baoshan Iron and Steel Limited Company, Shanghai 201900 (China); Liu, W.M. [Department of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030 (China); Hou, H. [Research Institute for Advanced Structural Steel, R and D Center, Baoshan Iron and Steel Limited Company, Shanghai 201900 (China)

    2009-01-15

    Continuous cooling transformation diagrams of the coarse grain heat-affected zone and microstructure after continuous cooling were investigated for 610 MPa class high-strength low-alloy (HSLA) structural steels with and without niobium. For the steel without Nb, grain boundary ferrite, degenerate pearlite and acicular ferrite are produced at slower cooling rates. Bainite phase is formed at faster cooling rates. However, for the steel with Nb, granular bainite is dominant at a large range of cooling rates. At cooling rates <32 K/s, transformation start temperature is decreased by 20 K approximately in the steel with Nb compared with that without Nb. Ferrite nucleation at prior austenite grain boundaries is suppressed and the cooling rate region for granular bainite transformation is broadened. At cooling rates >32 K/s, Nb addition has no obvious influence on transformation start temperature, but it influences microstructure transformation significantly. Martensite is observed in steel with Nb at faster cooling rates, but not produced in steel without Nb.

  7. Segregation behavior of phosphorus in the heat-affected zone of an A533B/A182 dissimilar weld joint before and after simulated thermal aging

    Science.gov (United States)

    Zhai, Ziqing; Miyahara, Yuichi; Abe, Hiroshi; Watanabe, Yutaka

    2014-09-01

    The segregation behavior of phosphorus (P) in the heat-affected zone (HAZ) of an A533B/A182 dissimilar weld joint before and after step cooling was investigated with atom probe tomography. At grain/packet boundaries, the final P segregation level consisted of non-equilibrium segregation that occurred during cooling after welding and post-weld heat treatment (PWHT) and equilibrium segregation that occurred during step cooling. In both processes, higher P coverage was observed in the coarse-grained and intercritically reheated coarse-grained HAZ than in the fine-grained HAZ and base material. The cooling after welding and PWHT seemed to have a pronounced impact on P segregation in the subsequent aging process. In addition, P segregation also occurred at the precipitate/matrix interfaces of cementite, Mo2C and Al-Si rich precipitates. The evolution of P coverage at these two types of sites suggested increasing risks of embrittlement with an increase in aging time.

  8. In situ observation of austenite grain growth behavior in the simulated coarse-grained heat-affected zone of Ti-microalloyed steels

    Institute of Scientific and Technical Information of China (English)

    Xiang-liang Wan; Kai-ming Wu; Gang Huang; Ran Wei; Lin Cheng

    2014-01-01

    The austenite grain growth behavior in a simulated coarse-grained heat-affected zone during thermal cycling was investigated via in situ observation. Austenite grains nucleated at ferrite grain boundaries and then grew in different directions through movement of grain boundaries into the ferrite phase. Subsequently, the adjacent austenite grains impinged against each other during theα→γtransformation. After theα→γtransformation, austenite grains coarsened via the coalescence of small grains and via boundary migration between grains. The growth process of austenite grains was a continuous process during heating, isothermal holding, and cooling in simulated thermal cy-cling. Abundant finely dispersed nanoscale TiN particles in a steel specimen containing 0.012wt%Ti effectively retarded the grain boundary migration, which resulted in refined austenite grains. When the Ti concentration in the steel was increased, the number of TiN particles de-creased and their size coarsened. The big particles were not effective in pinning the austenite grain boundary movement and resulted in coarse austenite grains.

  9. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    Science.gov (United States)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

    2014-12-01

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs.

  10. Microstructure and mechanical properties in the weld heat affected zone of 9Cr-2W-VTa reduced activation ferritic/martensitic steel for fusion

    International Nuclear Information System (INIS)

    Reduced activation ferritic/martensitic (RAFM) steel demonstrated excellent resistance to the neutron irradiation and mechanical properties. The investigation of weldability in company with the development of RAFM steel is essential for construction of the fusion reactor. Generally, the superior mechanical properties of the RAFM steel can be upset during welding process due to microstructural change by rapid heating and cooling in the weld heat affected zone (HAZ). The phase transformation and mechanical properties in the weld HAZ of RAFM steel were investigated. The base steel consisted of tempered martensite and two carbides. During rapid welding thermal cycle, the microstructure of the base steel was transformed into martensite and δ-ferrite. In addition, the volume fraction of δ-ferrite and grain size increased with increase in the peak temperature and heat input. The strength of the HAZs was higher than that of the base steel due to the formation of martensite, whereas the impact properties of the HAZs deteriorated as compared with the base steel due to the formation of δ-ferrite. The PWHT improved the impact properties of the HAZs, resulting from the formation of tempered martensite

  11. Microstructure and mechanical properties in the weld heat affected zone of 9Cr-2W-VTa reduced activation ferritic/martensitic steel for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joonoh; Lee, Changhoon; Lee, Taeho; Jang, Minho; Park, Mingu [Korea Institute of Materials Science, Changwon (Korea, Republic of); Kim, Hyoung Chan [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Reduced activation ferritic/martensitic (RAFM) steel demonstrated excellent resistance to the neutron irradiation and mechanical properties. The investigation of weldability in company with the development of RAFM steel is essential for construction of the fusion reactor. Generally, the superior mechanical properties of the RAFM steel can be upset during welding process due to microstructural change by rapid heating and cooling in the weld heat affected zone (HAZ). The phase transformation and mechanical properties in the weld HAZ of RAFM steel were investigated. The base steel consisted of tempered martensite and two carbides. During rapid welding thermal cycle, the microstructure of the base steel was transformed into martensite and δ-ferrite. In addition, the volume fraction of δ-ferrite and grain size increased with increase in the peak temperature and heat input. The strength of the HAZs was higher than that of the base steel due to the formation of martensite, whereas the impact properties of the HAZs deteriorated as compared with the base steel due to the formation of δ-ferrite. The PWHT improved the impact properties of the HAZs, resulting from the formation of tempered martensite.

  12. Quantification of the surface brackish water layer and frontal zones in southern Chilean fjords between Boca del Guafo (43°30‧S) and Estero Elefantes (46°30‧S)

    Science.gov (United States)

    Calvete, Carolina; Sobarzo, Marcus

    2011-03-01

    The southern Chilean region between the Boca del Guafo passage and Estero Elefantes contains one of the estuarine zones with the greatest freshwater influence on the planet. At the surface, plumes of freshwater from the fjord heads to their mouths, emptying into the Moraleda-Costa-Elefantes channel system and then the coastal ocean. The influence of this freshwater on the region's estuarine dynamics, coastal ecology, and biogeochemical processes has only recently begun to be elucidated. Using hydrographic data from the CIMAR-Fiordos cruises (1998-2001), this study quantifies the equivalent height of freshwater, emphasizing the role it plays in the potential energy anomaly and front locations, as well as its relationship with river discharges. Using a criterion of equivalent height of freshwater >15% (density 0.005 J/m 4. The frontal zones were located in the extreme southeast of Jacaf Channel, at the head of Ventisquero Sound, in the central part of the Puyuguapi and Moraleda channels, and at the head and mouth of Aysén Fjord. The equivalent height of freshwater and potential energy anomaly showed a good correlation with the accumulated (5-day) river discharges ( r2=0.87), which were greatest toward the fjord heads in spring. The brackish surface water had short residence times (3.5 days) in Aysen Fjord, unlike the deep layer, which other authors report to have a longer residence time (near 1 year).

  13. Impact of Land-use Systems on some Physical and Chemical Soil Properties of an Oxisol in the Humid Forest Zone of Southern Cameroon

    OpenAIRE

    Birang, AM.; Agoumé, V.

    2009-01-01

    A field study was carried out in the village Ngoungoumou in the humid forest zone of Cameroon to assess changes in particle size distribution and soil chemical properties in relation to different land-use systems. These strongly acid soils are mainly composed of clay and sand, and are generally devoid of crop nutrients at the benefit of exchangeable Al occupying the nearly entire exchange complex. The major portion of the nutrients is stored in the top-soil, together with the organic matter. ...

  14. Result of alpha track detection of radon in soil gas in the Khlong Marui Fault Zone, Southern Thailand: A possible earthquake precursor

    Directory of Open Access Journals (Sweden)

    Tripob Bhongsuwan

    2011-10-01

    Full Text Available Measurements of radon concentration in soil gas were conducted at ten stations (ST1-ST10, located mainly in theKhlong Marui Fault Zone, Thap Put District, Phang Nga Province over a period from 28 January to 25 April, 2007. The resultsof the radon concentration were presented as the variation of cumulative alpha track over a week period. At Station ST10 theradon concentrations are in general higher than those at other stations for every week. Two significant radon anomalies werefound to have the concentration above the mean value plus one standard deviation. During the period of monitoring thelocal and regional earthquake activities were observed showing patterns consistent with the occurrence of the radon anomalies.The maximum radon concentration is interpreted to be related to a possible influence of the pressure and stress increasedin the subsurface. An increase in the number of earthquakes is observed correlating to a lower radon concentration when thesubsurface pressure dropped due to tectonic stress release by seismic activities. Therefore, it would be possible to use thevariation of soil gas radon concentration as an earthquake precursor in the Khlong Marui Fault Zone.

  15. Schistosoma mansoni infection prevalence and associated risk factors among schoolchildren in Demba Girara, Damot Woide District of Wolaita Zone, Southern Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Bereket Alemayehu; Zewdneh Tomass

    2015-01-01

    Objective:To establish the prevalence and associated risk factors of Schistosoma mansoni (S. mansoni) infection among schoolchildren at a village in Wolaita Zone, Sothern Ethiopia. Methods:A cross-sectional study was carried out among primary schoolchildren. A total of 384 randomly selected study subjects provided stool samples for parasitological examination by Kato-Katz and Formalin-Ether concentration techniques. Secondary parasitological data were obtained from Health Center Laboratory to see the previous history of S. mansoni infection in the area. Statistical analysis was performed using SPSS software version 16. Results:From the total children examined, 85.4%were found positive for at least one helminth infection. S. mansoni infection (81.3%) was the most prevalent and the prevalence of STH was 32%. Moderate and heavy infection intensities were only observed in S. mansoni infections. The overall heavy intensity of infection was 56.4%. Contact to Bisare stream was the most important factor for S. mansoni infection (OR 3.9) followed by herding cattle near the stream (OR 2.527). Males were twice more likely to get the infection than females (OR 1.923). Analysis of secondary parasitological data showed that S. mansoni infection was a leading helminthic infection over the past years. Conclusions:The present study found a higher intensity and prevalence of S. mansoni infection in a rural village of Wolaita Zone. Therefore, appropriate integrated control and prevention measures need to be implemented in the study area.

  16. Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

    International Nuclear Information System (INIS)

    In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

  17. Effect of simulated thermal cycles on the microstructure of the heat-affected zone in HSLA-80 and HSLA-100 steel plates

    Science.gov (United States)

    Shome, M.; Gupta, O. P.; Mohanty, O. N.

    2004-03-01

    The influence of weld thermal simulation on the transformation kinetics and heat-affected zone (HAZ) microstructure of two high-strength low-alloy (HSLA) steels, HSLA-80 and HSLA-100, has been investigated. Heat inputs of 10 kJ/cm (fast cooling) and 40 kJ/cm (slow cooling) were used to generate single-pass thermal cycles with peak temperatures in the range of 750 °C to 1400 °C. The prior-austenite grain size is found to grow rapidly beyond 1100 °C in both the steels, primarily with the dissolution of niobium carbonitride (Nb(CN)) precipitates. Dilatation studies on HSLA-80 steel indicate transformation start temperatures (T s ) of 550 °C to 560 °C while cooling from a peak temperature (T p ) of 1000 °C. Transmission electron microscopy studies show here the presence of accicular ferrite in the HAZ. The T s value is lowered to 470 °C and below when cooled from a peak temperature of 1200 °C and beyond, with almost complete transformation to lath martensite. In HSLA-100 steel, the T s value for accicular ferrite is found to be 470 °C to 490 °C when cooled from a peak temperature of 1000 °C, but is lowered below 450 °C when cooled from 1200 °C and beyond, with correspondingly higher austenite grain sizes. The transformation kinetics appears to be relatively faster in the fine-grained austenite than in the coarse-grained austenite, where the niobium is in complete solid solution. A mixed microstructure consisting of accicular ferrite and lath martensite is observed for practically all HAZ treatments. The coarse-grained HAZ (CGHAZ) of HSLA-80 steel shows a higher volume fraction of lath martensite in the final microstructure and is harder than the CGHAZ of HSLA-100 steel.

  18. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    Science.gov (United States)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  19. Low shear velocity in a normal fault system imaged by ambient noise cross correlation: The case of the Irpinia fault zone, Southern Italy

    Science.gov (United States)

    Vassallo, Maurizio; Festa, Gaetano; Bobbio, Antonella; Serra, Marcello

    2016-06-01

    We extracted the Green's functions from cross correlation of ambient noise recorded at broadband stations located across the Apennine belt, Southern Italy. Continuous records at 26 seismic stations acquired for 3 years were analyzed. We found the emergence of surface waves in the whole range of the investigated distances (10-140 km) with energy confined in the frequency band 0.04-0.09 Hz. This phase reproduces Rayleigh waves generated by earthquakes in the same frequency range. Arrival time of Rayleigh waves was picked at all the couples of stations to obtain the average group velocity along the path connecting the two stations. The picks were inverted in separated frequency bands to get group velocity maps then used to obtain an S wave velocity model. Penetration depth of the model ranges between 12 and 25 km, depending on the velocity values and on the depth of the interfaces, here associated to strong velocity gradients. We found a low-velocity anomaly in the region bounded by the two main faults that generated the 1980, M 6.9 Irpinia earthquake. A second anomaly was retrieved in the southeast part of the region and can be ascribed to a reminiscence of the Adria slab under the Apennine Chain.

  20. Physical and biological control of protistan community composition, distribution and abundance in the seasonal ice zone of the Southern Ocean between 30 and 80°E

    Science.gov (United States)

    Davidson, Andrew T.; Scott, Fiona J.; Nash, Geraldine V.; Wright, Simon W.; Raymond, Ben

    2010-05-01

    Protists are critical components of the Antarctic marine ecosystem as they comprise most of the living carbon and are the base of the Antarctic food web. They are also key determinants of vertical carbon flux and mediate draw-down of atmospheric CO 2 by the ocean. The community composition, abundance and distribution of marine protists (phytoplankton and protozoa) was studied during the Baseline Research on Oceanography, Krill and the Environment-West (BROKE-West) survey, in the seasonal ice zone during the 2005-2006 austral summer between 30°E and 80°E. Light and electron microscopy were used to determine the protistan composition and abundance in samples obtained at 30 sites from surface waters and at 26 sites from the depth of the maximum in situ chlorophyll fluorescence (Chl max). Cluster analysis was used to identify 5 groups of sample sites at the surface and 5 at the Chl max that were of similar protist composition and abundance. The physical characteristics, taxonomic composition, indicator taxa, and taxonomic diversity were determined for each group. In the southwest, a bloom of colonial Phaeocystis antarctica dominated the protistan community composition and biomass amongst the receding ice, but this was replaced by the flagellate life stage/s of this haptophyte in waters to the north. In the southeast, a diatom bloom had the highest diversity of protist taxa observed during the survey and centric diatoms dominated the biomass. Outside these blooms, grazing by krill probably reduced the composition and abundance of large diatoms and autotrophic dinoflagellates in coastal to mid-inshore waters. Only in offshore waters did large diatoms and dinoflagellates increase in abundance and diversity, despite low concentrations of iron and silicate at many of these sites. This increase was probably due to reduced top-down control by krill and other large zooplankton. Large diatoms dominated in offshore waters, despite other coincident studies showing that the

  1. U-Pb dating of granodiorite and granite units of the Los Pedroches batholith. Implications for geodynamic models of the southern Central Iberian Zone (Iberian Massif)

    Science.gov (United States)

    Carracedo, M.; Paquette, J. L.; Alonso Olazabal, A.; Santos Zalduegui, J. F.; García de Madinabeitia, S.; Tiepolo, M.; Gil Ibarguchi, J. I.

    2009-10-01

    The first U-Pb geochronological results on the magmatic alignment of the Los Pedroches batholith are presented. The batholith is composed of a main granodioritic unit, several granite plutons and an important acid to basic dyke complex, all of them intrusive after the main Variscan regional deformation phase, D1, along the boundary between the Ossa-Morena and Central Iberian zones (SW Iberian Massif). Zircons from samples on both extremes of the granodiorite massif record nearly simultaneous magmatic crystallization at ca. 308 Ma, while the emplacement of granite plutons was diachronic between 314 and 304 Ma. The U-Pb results combined with new field and textural observations allow to better constrain the age of Variscan deformations D2 and D3 across the region, while the age of D1 remains imprecise. Transcurrent D2 shearing-tightening of D1 folds occurred around 314 Ma (lower Westphalian) in relation to the emplacement of the first granitic magmas. D3 faults and shear bands bearing a strong extensional component developed at ca. 308 Ma (upper Westphalian), associated to the intrusion of the main granodiorite pluton (granodiorite) of the batholith. Together with available geochemical and geophysical information, these results point to the Variscan reactivation of lithospheric fractures at the origin and subsequent emplacement of hybrid magmas within this sector of the Massif.

  2. A seismogenic zone in the deep crust indicated by pseudotachylytes and ultramylonites in granulite-facies rocks of Calabria (Southern Italy)

    Science.gov (United States)

    Altenberger, U.; Prosser, G.; Grande, A.; Günter, C.; Langone, A.

    2013-10-01

    Pseudotachylyte veins frequently associated with mylonites and ultramylonites occur within migmatitic paragneisses, metamonzodiorites, as well as felsic and mafic granulites at the base of the section of the Hercynian lower crust exposed in Calabria (Southern Italy). The crustal section is tectonically superposed on lower grade units. Ultramylonites and pseudotachylytes are particularly well developed in migmatitic paragneisses, whereas sparse fault-related pseudotachylytes and thin mylonite/ultramylonite bands occur in granulite-facies rocks. The presence of sillimanite and clinopyroxene in ultramylonites and mylonites indicates that relatively high-temperature conditions preceded the formation of pseudotachylytes. We have analysed pseudotachylytes from different rock types to ascertain their deep crustal origin and to better understand the relationships between brittle and ductile processes during deformation of the deeper crust. Different protoliths were selected to test how lithology controls pseudotachylyte composition and textures. In migmatites and felsic granulites, euhedral or cauliflower-shaped garnets directly crystallized from pseudotachylyte melts of near andesitic composition. This indicates that pseudotachylytes originated at deep crustal conditions (>0.75 GPa). In mafic protoliths, quenched needle-to-feather-shaped high-alumina orthopyroxene occurs in contact with newly crystallized plagioclase. The pyroxene crystallizes in garnet-free and garnet-bearing veins. The simultaneous growth of orthopyroxene and plagioclase as well as almandine, suggests lower crustal origin, with pressures in excess of 0.85 GPa. The existence of melts of different composition in the same vein indicates the stepwise, non-equilibrium conditions of frictional melting. Melt formed and intruded into pre-existing anisotropies. In mafic granulites, brittle faulting is localized in a previously formed thin high-temperature mylonite bands. migmatitic gneisses are deformed into

  3. Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S-70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

    Science.gov (United States)

    Salas, Pablo A.; Rabbia, Osvaldo M.; Hernández, Laura B.; Ruprecht, Philipp

    2016-06-01

    In the Andean Southern Volcanic Zone (SVZ), the broad distribution of mafic compositions along the recent volcanic arc occurs mainly south of 37°S, above a comparatively thin continental crust (≤~35 km) and mostly associated with the dextral strike-slip regime of the Liquiñe-Ofqui Fault Zone (LOFZ). North of 36°S, mafic compositions are scarce. This would be in part related to the effect resulting from protracted periods of trapping of less evolved ascending magmas beneath a thick Meso-Cenozoic volcano-sedimentary cover that lead to more evolved compositions in volcanic rocks erupted at the surface. Here, we present whole-rock and olivine mineral chemistry data for mafic rocks from four monogenetic vents developed above a SVZ segment of thick crust (~45 km) in the Descabezado Grande volcanic field (~35.5°S). Whole-rock chemistry (MgO > 8 wt%) and compositional variations in olivine (92 ≥ Fo ≥ 88 and Ni up to ~3650 ppm) indicate that some of the basaltic products erupted through these vents (e.g., Los Hornitos monogenetic cones) represent primitive arc magmas reaching high crustal levels. The combined use of satellite images, regional data analysis and field observations allow to recognize at least 38 mafic monogenetic volcanoes dispersed over an area of about 5000 km2 between 35.5° and 36.5°S. A link between ancient structures inherited from pre-Andean tectonics and the emplacement and distribution of this mafic volcanism is suggested as a first-order structural control that may explain the widespread occurrence of mafic volcanism in this Andean arc segment with thick crust.

  4. High-precision differential earthquake location in 3-D models: evidence for a rheological barrier controlling the microseismicity at the Irpinia fault zone in southern Apennines

    Science.gov (United States)

    De Landro, Grazia; Amoroso, Ortensia; Stabile, Tony Alfredo; Matrullo, Emanuela; Lomax, Antony; Zollo, Aldo

    2015-12-01

    A non-linear, global-search, probabilistic, double-difference earthquake location technique is illustrated. The main advantages of this method are the determination of comprehensive and complete solutions through the probability density function (PDF), the use of differential arrival times as data and the possibility to use a 3-D velocity model both for absolute and double-difference locations, all of which help to obtain accurate differential locations in structurally complex geological media. The joint use of this methodology and an accurate differential time data set allowed us to carry out a high-resolution, earthquake location analysis, which helps to characterize the active fault geometries in the studied region. We investigated the recent microseismicity occurring at the Campanian-Lucanian Apennines in the crustal volume embedding the fault system that generated the 1980 MS 6.9 earthquake in Irpinia. In order to obtain highly accurate seismicity locations, we applied the method to the P and S arrival time data set from 1312 events (ML models optimized for the area under study. Both manually refined and cross-correlation refined absolute arrival times have been used. The refined seismicity locations show that the events occur in a volume delimited by the faults activated during the 1980 MS 6.9 Irpinia earthquake on subparallel, predominantly normal faults. We find an abrupt interruption of the seismicity across an SW-NE oriented structural discontinuity corresponding to a contact zone between different rheology rock formations (carbonate platform and basin residuals). This `barrier' appears to be located in the area bounded by the fault segments activated during the first (0 s) and the second (18 s) rupture episodes of the 1980s Irpinia earthquake. We hypothesize that this geometrical barrier could have played a key role during the 1980 Irpinia event, and possibly controlled the delayed times of activation of the two rupture segments.

  5. Understanding of microstructures in the heat affected zone of boron-added modified 9Cr-1Mo steel using gleeble simulation

    International Nuclear Information System (INIS)

    Beneficial effect of boron on improving the creep properties and resistance to Type IV cracking of the ferritic steels is now well established. It has also been shown that boron significantly influence the ferrite to austenite transformation that takes place in the heat affected zone (HAZ) of a weld joint of ferritic steel and this in turns alters the HAZ microstructure from those observed in the boron free steels and thus improving the resistance to Type IV cracking. In the present study transformation of tempered martensite to austenite for two boron containing 9Cr-1Mo steels when subjected to different weld thermal cycles were examined. Studies using Differential Scanning Calorimeter (DSC) carried out on one of the steels showed that both Ac1 and Ac3 temperatures increased with increase in heating rates. Heating and cooling rates in weld thermal cycles is higher than that could be achieved using a DSC and Gleeble simulation of the weld thermal cycle showed that transformation temperatures obtained were still higher than that obtained using a DSC. Examination of the microstructures in the as-simulated condition and after subjecting to heat treatment of 760 C/3h confirmed there is no grain refinement, normally expected in a conventional boron free 9Cr-1Mo steel. Subsequently, these steels were given isothermal heat treatment in a furnace at temperatures of 875 and 900 C for short durations of 5-60 minutes to allow different extents of transformation of tempered martensite to austenite and their effect on the final microstructures. Stability of microstructure in boron containing two modified 9Cr-1Mo steels was studied using Gleeble thermal simulator by varying peak temperatures from 875 to 1000 C. Results of modified 9Cr-1Mo steel was used for comparison purpose. Ac1 and Ac3 transformation temperatures are found to be similar as estimated from the DSC and Gleeble thermal simulator using C strain technique. Lath martensitic microstructure was observed in both these

  6. Grown-out of seeds of the taquilla clam Mulinia edulis (King & Broderip, 1832 in the subtidal zone in northern Chile and in the intertidal zone in southern Chile Engorda de semillas de la almeja taquilla Mulinia edulis (King & Broderip, 1832 en la zona submareal en el norte y en la zona intermareal en el sur de Chile

    Directory of Open Access Journals (Sweden)

    Alejandro Abarca

    2012-09-01

    Full Text Available Seeds of the clam Mulinia edulis produced in a hatchery were grown in bottom cages in the subtidal zone of Tongoy Bay (northern Chile and in the intertidal zone of Chullec (Chiloé Island, southern Chile, to compare the growth and survival of small and large seeds of the same production in different environments and latitudes. Seeds were shipped twice to Chullec, once in summer and once in winter. Previous experiments with seed transportation (14.2 ± 2.4 mm showed that they are able to survive more than 24 h out of water. The growth rate of both large and small seeds was greater in Tongoy than in Chullec, reaching maxima of 1.24 mm month-1 in the small seeds of Tongoy and 1.06 mm month-1 in the same group in Chullec. The growth rates obtained for M. edulis were similar to those described for other cultured clams. Seeds grown in Chullec presented a significantly greater weight by size than the seeds grown in Tongoy. Survival after 12 months was 38% and 88% in Tongoy and 19.4% and 37.3% in Chullec for small and large seeds, respectively. Seeds produced in hatcheries are able to withstand long travel (1,360 km and grow in the intertidal zone of southern Chile, where the operation of the culture is simple and cheap. The growth curve presents an inflection point around 20 mm length, probably related to the age at sexual maturity. Growing out seeds in the intertidal zone in southern Chile is seen as a new activity for artisanal fishermen.Semillas de la almeja Mulinia edulis producidas en el Hatchery de Pesquera San José (Tongoy fueron engordadas en sistemas de fondo en la zona submareal de bahía Tongoy e intermareal en Chullec (Chiloé, para comparar el crecimiento y la supervivencia de semillas pequenas y grandes de una misma producción en diferentes ambientes y latitudes. Se realizaron dos envíos de semillas a Chullec, uno en verano y otro en invierno. Experimentos de simulación del transporte de semillas (14,2 ± 2,4 mm muestran que

  7. Analysis on Climate Change in the Northern and Southern Marginal Zones of the Badain Juran Desert during the Period 1960 -2009%1960-2009年巴丹吉林沙漠南北缘气候变化分析

    Institute of Scientific and Technical Information of China (English)

    马宁; 王乃昂; 李卓仑; 陈秀莲; 朱金峰; 董春雨

    2011-01-01

    利用巴丹吉林沙漠北缘的额济纳旗、拐子湖和南缘的阿拉善右旗、雅布赖4个气象站,1960-2009年逐月平均气温、降水量和相对湿度资料,运用一元线性回归、趋势系数分析和5年滑动平均方法,分析近50年来沙漠南北缘气候变化趋势.结果发现:近50年来,巴丹吉林沙漠南北缘年平均气温显著升高,升温速率为0.27~0.48℃/10 a,高于同期全国和西北地区东部平均升温速率.北缘的年平均气温升温速率和升温趋势均大于南缘.南北缘各季节年均气温显著升高,各站均表现为冬季升温速率最大,但各季节平均气温的升温趋势有差异.巴丹吉林沙漠南北缘各站年降水量波动很大.近50年来,北缘年降水量略有减少,南缘略有增加.各站点季节降水量变化趋势亦不明显,且不同站点变化特征不同.沙漠南北缘湿润度很低,属极干旱等级.近50年来,北缘年平均湿润度略有下降,南缘则略有上升,但湿润度的变化趋势不明显.%In this paper, the basic characteristics of climate change in the northern and southern marginal zones of the Badain Juran Desert are analyzed using the linear regression, trend factor analysis and 5-year moving average based on the observed data of monthly mean air temperature, precipitation and relative humidity, recorded by 4 meteorological stations including Erjina Banner and Guaizihu in the northern marginal zone of the desert and Alxa Right Banner and Yabra in the southern marginal zone during the period 1960 -2009. The results show that there was a significant temperature increase in the southern and northern marginal zones of Badain Juran Desert in recent 50 years. The increase rate of mean annual temperature varied in a range of 0. 28 -0. 48 ℃/10 a, and it was higher than the national average and the average in the eastern part of northwest China, in which it was higher in the northern marginal zone than in the southern marginal zone. The

  8. Fall diets of alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario during 1994-2005 with an emphasis on occurrence of Mysis relicta

    Science.gov (United States)

    Walsh, M.G.; O'Gorman, R.; Strang, T.; Edwards, W.H.; Rudstam, L. G.

    2008-01-01

    In Lake Ontario, factors including the collapse of the burrowing amphipod, Diporeia spp., changes in the distribution and composition of the prey fish community, and occurrence of exotic cladocerans Bythotrephes longimanus and Cercopagis pengoi have led to changes in predation pressure on the remaining native profundal macroinvertebrate, Mysis relicta. We conducted a diet study on three important prey fishes, alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and slimy sculpin (Cottus cognatus) in 2002-2005 at depths 75-130 m along the south shore of Lake Ontario to evaluate the current role of Mysis in the diets of these species relative to earlier studies and previously unpublished data from 1994-1995. Mysis have remained an important prey item for alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario through 2005, indicating that the population has been able to sustain itself following the collapse of Diporeia. Although the occurrence of Diporeia in prey fish diets was minimal in 2003-2005, Bythotrephes longimanus and Cercopagis pengoi played an important role in the diet of alewife and a minor role in the diet of rainbow smelt, and may actually serve to mitigate predation pressure on Mysis, particularly in years when they are very abundant. Conversely, without Diporeia, the benthic slimy sculpin was primarily reliant on Mysis as a prey item and would be most vulnerable to a decline in the Mysis population. Copyright ?? 2008 AEHMS.

  9. Statistical eruption forecast for the Chilean Southern Volcanic Zone: typical probabilities of volcanic eruptions as baseline for possibly enhanced activity following the large 2010 Concepción earthquake

    Directory of Open Access Journals (Sweden)

    Y. Dzierma

    2010-10-01

    Full Text Available A probabilistic eruption forecast is provided for ten volcanoes of the Chilean Southern Volcanic Zone (SVZ. Since 70% of the Chilean population lives in this area, the estimation of future eruption likelihood is an important part of hazard assessment. After investigating the completeness and stationarity of the historical eruption time series, the exponential, Weibull, and log-logistic distribution functions are fit to the repose time distributions for the individual volcanoes and the models are evaluated. This procedure has been implemented in two different ways to methodologically compare details in the fitting process. With regard to the probability of at least one VEI ≥ 2 eruption in the next decade, Llaima, Villarrica and Nevados de Chillán are most likely to erupt, while Osorno shows the lowest eruption probability among the volcanoes analysed. In addition to giving a compilation of the statistical eruption forecasts along the historically most active volcanoes of the SVZ, this paper aims to give "typical" eruption probabilities, which may in the future permit to distinguish possibly enhanced activity in the aftermath of the large 2010 Concepción earthquake.

  10. Evolution de l'état de précipitation dans un alliage Al-Zn-Mg lors de traitements thermiques anisothermes et dans la zone affectée thermiquement de joints soudés

    OpenAIRE

    Nicolas, Myriam

    2002-01-01

    Le soudage des alliages Al-Zn-Mg est de plus en plus utilisé dans l'industrie du transport. Les variations brutales de température induites par le soudage à l'arc provoquent des modifications importantes de la microstructure dans la zone dite affectée thermiquement.Cette étude porte sur l'évolution de la précipitation suite à ce procédé de l'alliage 7108.50 présentant différentes microstructures initiales. Une caractérisation fine des précipités durcissants dans la zone affectée thermiquement...

  11. Infaunal community responses to a gradient of trawling disturbance and a long-term Fishery Exclusion Zone in the Southern Tyrrhenian Sea

    Science.gov (United States)

    Mangano, M. Cristina; Kaiser, Michel J.; Porporato, Erika M. D.; Lambert, Gwladys I.; Rinelli, Paola; Spanò, Nunziacarla

    2014-03-01

    Historically the majority of Mediterranean trawl fisheries occur on the continental shelf with a smaller proportion focused on the shelf slope and deep sea areas. Understanding how trawl fisheries affect the wider ecosystem is an important component of the ecosystem-based approach to fisheries management. In this context the current study examined the impact of the otter trawl fishery on the infaunal communities found on the continental shelf and upper slope off the coast of Sicily and Calabria, Italy. A total of thirty six sites were sampled across a gradient of fishing intensity and from within a large bay from which trawling has been excluded for 22 years. Fishing intensities were ascertained post-hoc from vessel monitoring system data. Seabed characteristics of the sites studied were uniform across the continental shelf and slope areas that were studied, such that the only factor that varied was fishing intensity. The density index (DI) and total number of species (S) were significantly higher in the fishery closure area compared with other continental shelf sites. In particular, bioturbating decapod fauna occurred only within the fishery closure area. Fished sites were dominated primarily by burrowing deposit feeding worms, small bivalves and scavenging biota. In contrast, the response to fishing on the upper slope was less clear. This observation was treated with caution as the power to detect fishing effects was lower for the upper slope sites as a result of possible illegal fishing that had compromised two of the four replicate sites within the closed area. While the present study was able to quantify the effect of the demersal trawl fleet on the benthic infauna of the continental shelf, the effects of trawling on the upper shelf slope remain unclear and warrant further study.

  12. INFLUENCE OF SOWING DATE AND CROP VARIETY ON PHENOLOGY, GROWTH AND YIELD OF RAINFED GROUNDNUT (ARACHIS HYPOGAEA L. IN SOUTHERN ZONE OF ANDHRA PRADESH, INDIA

    Directory of Open Access Journals (Sweden)

    T. Prathima

    2013-03-01

    Full Text Available An experiment was conducted with four dates of sowing (Second fortnight of May, First fortnight of June, Second fortnight of June and First fortnight of July and four Varieties (TMV-2, JL-24, Narayani and Abhaya. There was wide variation in the weather conditions that prevailed over the cropping periods between the two years of experimentation. During the first year (2006 a continuous dryspell of 51 days prevailed which coincided with different growth stages of groundnut under different dates of sowing. This dry spell has not favoured the growth and development of crop, instead, it has increased the crop duration of different varieties of groundnut studied under the present investigation. The crop duration was 139-146 days in early sown crop to 110-125 days in normal sown crop compared to normal duration of 105 to 120 days. However, the second year (2007 is normal with better temporal distribution of rains and the crop duration ranged from 104-120 days in early sown crop to 108-121 days under normal sown crop. The length of growth period in 2006 is due to receipt of continuous rains after dry spell of 51 days from seed development phase to physiological maturity. In 2007,the crop which received heavy rains (22 June sown crop from 90 DAS to harvest was adversely affected resulting poor filling and low yields. The results revealed that Sowing during July first fortnight was found to be optimum time for groundnut during drought year, while during normal year advancing the sowing date by one month may also favour good crop provided there were good rains. The performance of Abhaya cultivar was better than the Narayani, TMV-2 and JL-24 under different kinds of environments like extreme moisture stress, stress free or even under moderate stress conditions. However, in normal year TMV-2 and JL-24 performance was also good compared to drought year.

  13. Effects of phosphorus segregation on stress corrosion cracking in the heat-affected zone of a dissimilar weld joint between a Ni-base alloy and a low alloy steel

    International Nuclear Information System (INIS)

    Highlights: • Effect of P segregation on SCC in Alloy 182-A533B dissimilar weld was studied. • Segregation of solutes was mainly induced by welding and step cooling. • P segregation promoted crack growth/reactivation in heat-affected zone of A533B. • Crack in heat-affected zone prefers grain boundary and cementite–matrix interface. - Abstract: Effects of phosphorus segregation on stress corrosion cracking (SCC) in the heat-affected zone of an Alloy 182-A533B dissimilar weld joint in high-temperature, oxygenated water doped with SO42− and Cl− were evaluated by creviced bent beam test. Results indicate that step cooling and the addition of Cl− promoted SCC propagation and reactivation in the HAZ after cracks reach the fusion boundary. It is also suggested that phosphorus segregation at grain/packet boundaries and precipitate–matrix interfaces have promoted SCC, especially in coarse-grained HAZ and intercritically reheated coarse-grained HAZ

  14. Shoot Photosynthesis and Root Growth of Hybrid and Conventional Rice Cultivars as Affected by N and K Levels in the Root Zone

    Institute of Scientific and Technical Information of China (English)

    YANGXIAOE; V.ROEMHELD; 等

    1997-01-01

    Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid an cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty).The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply,bu the effect was greater for the hybrid.Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant,in which the effects were much more obvious in the hybrid rice than in the cultivar.High NK supply in the root zone stimulated the root growth,and decreased pH and increased the oxidation zone in the rhizosphere in both entries,but to a greater extent in the hybrid .The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice,particularly in hybrid rice.

  15. Effect of Mg Addition on Inhibiting Austenite Grain Growth in Heat Affected Zones of Ti-Bearing Low Carbon Steels%Effect of Mg Addition on Inhibiting Austenite Grain Growth in Heat Affected Zones of Ti-Bearing Low Carbon Steels

    Institute of Scientific and Technical Information of China (English)

    ZHU Kai; YANG Jian; WANG Rui-zhi; YANG Zhen-guo

    2011-01-01

    To study the effect of Mg addition on inhibiting weld heat affected zones (HAZ) austenite grain growth of Ti-bearing low carbon steels, two steels with and without Mg treated were prepared using a laboratory vacuum. The welding testing was simulated by Gleeble 3500 thermomechanical simulator. The performance of HAZ was investiga ted that the toughness was improved from 3.3 to 185 J by adding 0. 005%Mg (in mass percent) to the steel, and the fracture mechanism changed from cleavage fracture to toughness fracture. Through in-situ observation by a confocal scanning laser microscope, a significant result was found that the austenite grain of the steel with Mg treated was still keeping fine-grained structure after holding at 1 400℃ and lasting for 300 s. This inhibition of austenite grain growth was mainly attributed to the formation of pinning particles after the addition of Mg. The obtained results pro pose a potential method for improving HAZ toughness of structure steels.

  16. 骨料及界面区对混凝土渗透性影响试验%Affect of aggregate and interfacial transition zone on the permeability of concrete

    Institute of Scientific and Technical Information of China (English)

    虞爱平; 吕海波; 韦克宇

    2014-01-01

    混凝土渗透性一直是混凝土耐久性能的重要指标,为了探求混凝土中骨料及界面区对混凝土渗透性能的影响,试验引入了混凝土界面区,将混凝土看成是由砂浆、骨料及两者的界面区共同组成的三相材料,通过砂浆及规则骨料混凝土的快速渗透试验,计算各试件的混凝土氯离子扩散系数,进而分析骨料及界面区对混凝土渗透性能的影响。结果表明:当混凝土中骨料含量增加10%时,其扩散系数将下降12.7%;而当骨料含量增加到20%,其扩散系数下降了33.8%,骨料对混凝土渗透性有着较大的影响;混凝土中界面区扩散系数约为砂浆扩散系数的40倍,混凝土中界面区的增长也将增大混凝土的渗透性能。%Permeability of concrete has been an important indicator of the durability of concrete ,in order to explore the affect of aggre-gate and interfacial transition zone on the permeability of concrete. The interfacial transition zone was introduced in the test;concrete is seen as a three-phase material is composed with the mortar,aggregates and interfacial transition zone. Base on the rapid penetration tests was launch on mortar and rule aggregate concrete specimens,the chloride ion diffusion coefficient of specimens were calculated,and the affect of aggregate and interfacial transition zone on the permeability of concrete was further analyzed. The result showed that aggregate had a greater impact on the permeability of concrete. When the concrete aggregate content increased by 10%,the diffusion coefficient will decrease by 12.7%;and when aggregate content increased by 20%,the diffusion coefficient decreased by 33.8%. The diffusion coefficient in interfacial transition zone was about 40 times in mortar,an increase in the interfacial zone of concrete will also increase the permeability of concrete.

  17. The Galicia-Ossa-Morena Zone: Proposal for a new zone of the Iberian Massif. Variscan implications

    Science.gov (United States)

    Arenas, Ricardo; Díez Fernández, Rubén; Rubio Pascual, Francisco J.; Sánchez Martínez, Sonia; Martín Parra, Luis Miguel; Matas, Jerónimo; González del Tánago, José; Jiménez-Díaz, Alberto; Fuenlabrada, Jose M.; Andonaegui, Pilar; Garcia-Casco, Antonio

    2016-06-01

    Correlation of a group of allochthonous terranes (referred to as basal, ophiolitic and upper units) exposed in the NW and SW of the Iberian Massif, is used to propose a new geotectonic zone in the southern branch of the Variscan Orogen: the Galicia-Ossa-Morena Zone. Recent advances in SW Iberia identify most of the former Ossa-Morena Zone as another allochthonous complex of the Iberian Massif, the Ossa-Morena Complex, equivalent to the Cabo Ortegal, Órdenes, Malpica-Tui, Bragança and Morais complexes described in NW Iberia. The new geotectonic zone and its counterparts along the rest of the Variscan Orogen constitute an Internal Variscan Zone with ophiolites and units affected by high-P metamorphism. The Galicia-Ossa-Morena Zone includes a Variscan suture and pieces of continental crust bearing the imprint of Ediacaran-Cambrian events related to the activity of peri-Gondwanan magmatic arcs (Cadomian orogenesis). In the Iberian Massif, the general structure of this geotectonic zone represents a duplication of the Gondwanan platform, the outboard sections being juxtaposed on top of domains located closer to the mainland before amalgamation. This interpretation offers an explanation that overcomes some issues regarding the differences between the stratigraphic and paleontological record of the central and southern sections of the Iberian Massif. Also, equivalent structural relationships between other major geotectonic domains of the rest of the Variscan Orogen are consistent with our interpretation and allow suspecting similar configurations along strike of the orogen. A number of issues may be put forward in this respect that potentially open new lines of thinking about the architecture of the Variscan Orogen.

  18. Detection of violations in thermal cycle of electric arc welding of heat resistant steel 12Kh1MF using magnetic properties of a heat affected zone

    International Nuclear Information System (INIS)

    The studies on the magnetic characteristics of the 12Kh1M1F heat resistant steel are carried out in the zones of melting and thermal effect by different modes of the electric are welding and the new approach to calculating and forecasting the longevity of service of the steam pipe welded joints is proposed on the basis of the magnetic structuroscopy. The local step-by-step (with the 1-2 mm interval) measurement of the metal residual magnetization after magnetization through the point pole method is accomplished in the welded joint area after the removal of the weld reinforcement. The evaluating of the welding modes violations and the joint longevity forecast are given in the basis of the maximum and minimum measurement results or their distribution along the measurement line

  19. Sea Surface Temperatures Mediated by the El Niño-Southern Oscillation Affect Birds Breeding in Temperate Coastal Rain Forests

    Directory of Open Access Journals (Sweden)

    Anthony J. Gaston

    2005-12-01

    Full Text Available We studied the timing of breeding and juvenile/adult ratios among songbirds in temperate rain forests over four years on the Haida Gwaii (Queen Charlotte Islands archipelago, British Columbia. In May 1998, air temperatures in Haida Gwaii were above average, whereas in 1999 they were the lowest in 20 yr: temperatures in the other two years were closer to normal, although 2001 was almost as cold as 1999. Temperatures closely followed the patterns of sea surface temperatures created by the 1997–1998 El Niño, i.e., warm, event and the subsequent strong La Niña, i.e., cool, event. Timing of breeding, as measured by the first capture of juveniles or by direct observations of hatching, varied by approximately 19 d between the earliest (1998 and latest (1999 years. In 1998, the proportion of juveniles among birds trapped increased steeply as soon as young birds began to appear. In other years, the rate of increase was slower. In 1999, the peak proportions of hatching-year individuals among the foliage-gleaning insectivores, i.e., the Orange-crowned Warbler (Vermivora celata, Townsend's Warbler (Dendroica townsendi, and the Golden-crowned Kinglet (Regulus satrapa, were lower than in other years, with almost no young Orange-crowned Warblers captured at all. The pattern of variation in the timing of breeding and in the proportion of hatching-year individuals trapped fitted the temperature data well, although rainfall may also have contributed. We concluded that changes mediated by El Niño-Southern Oscillation (ENSO in sea surface temperatures off northern British Columbia, through their effects on air temperatures, had a strong effect on the breeding of forest birds, to the point of causing nearly complete reproductive failure for one species in 1999. An intensification of the ENSO cycle could lead to more erratic reproduction for some species.

  20. Localized ageing in the heat affected zone of welded X5CrNiCuNbl6-4 and X4CrNiSiTi14-7 sheets

    International Nuclear Information System (INIS)

    Localized ageing and corresponding microstructural developments as a result of welding heat in the heat-affected zone (HAZ) of two different precipitation-hardened Cr-Steels (X5CrNiCuNb16-4 and X4CrNiSiTi14-7) have been studied. The X5CrNiCuNb16-4 sheet was in solution annealed condition and X4CrNiSiTi14-7 sheet was in peak aged condition. The results showed that despite of initial heat treated condition, the fusion zone formed in both welded sheets has typical cast structure. The HAZ has different microstructure compared to fusion zone and base metal. The HAZ is found to be sensitive to the welding heat and was aged locally due to thermal effects of welding. This localized ageing forms regions in HAZ varying from over-aged to under aged, depending upon the initial ageing condition of the base sheet

  1. Vulnerabilidades sociais e juvenil nos mananciais da zona sul da cidade de São Paulo Social vulnerabilities and youth in the water catchment areas of the southern zone of the city of São Paulo

    Directory of Open Access Journals (Sweden)

    Elizabeth Borelli

    2012-06-01

    Full Text Available Este artigo é um produto parcial da pesquisa "Reflexos da Vulnerabilidade Socioambiental nas Manifestações Musicais dos Jovens Paulistanos da Periferia", identificando como recorte geográfico a periferia da Zona Sul da cidade de São Paulo. Trata-se de uma região que começou a se formar devido à ocupação populacional desordenada em áreas de manancial, onde a vulnerabilidade social é agravada por situações de risco e degradação ambiental, dado o adensamento das áreas de favelas, configurando um processo de exclusão ambiental e urbana. Temporalmente, a pesquisa parte da década de 1980, quando se expande o padrão de extensão da periferia e surgem as manifestações culturais nas periferias dos grandes centros urbanos. Nesta reflexão, a relação entre política e cultura é apresentada através da análise dos mecanismos de sociabilidade que articulam os jovens afrodescendentes das periferias em torno de intervenções culturais coletivas, como formas de criação e reprodução da sua realidade social.This article is a partial product of the study "Reflexes of the Socio-environmental Vulnerability in the Musical Manifestations of Paulista Youth from the Periphery," which focuses on the Southern Zone of the city of São Paulo. This is a region that took shape through the unordered occupation of water catchment areas, where social vulnerability is aggravated by situations of risk and environmental degradation, given the increased density of favela regions, establishing a process of environmental and urban exclusion. The study begins in the 1980s, when the pattern of extension of the periphery expanded and cultural manifestations arose in the peripheries of the large urban centers. In this reflection, the relationship between politics and culture is presented through the analysis of the mechanisms of sociability that articulate Afro-descendent youth from the periphery around collective cultural interventions, as forms of creation

  2. Treatment Outcome of Tuberculosis Patients under Directly Observed Treatment Short Course and Factors Affecting Outcome in Southern Ethiopia: A Five-Year Retrospective Study.

    Directory of Open Access Journals (Sweden)

    Gebremedhin Gebrezgabiher

    Full Text Available Tuberculosis (TB is one of the major public health and socio-economic issues in the 21st century globally. Assessment of TB treatment outcomes, and monitoring and evaluation of its risk factors in Directly Observed Treatment Short Course (DOTS are among the major indicators of the performance of a national TB control program. Hence, this institution-based retrospective study was conducted to determine the treatment outcome of TB patients and investigate factors associated with unsuccessful outcome at Dilla University Referral Hospital, southern Ethiopia. Five years (2008 to 2013 TB record of TB clinic of the hospital was reviewed. A total 1537 registered TB patients with complete information were included. Of these, 942 (61.3% were male, 1015 (66% were from rural areas, 544 (35.4% were smear positive pulmonary TB (PTB+, 816 (53.1% were smear negative pulmonary TB (PTB- and 177(11.5% were extra pulmonary TB (EPTB patients. Records of the 1537 TB patients showed that 181 (11.8% were cured, 1129(73.5% completed treatment, 171 (11.1% defaulted, 52 (3.4% died and 4 (0.3% had treatment failure. The overall mean treatment success rate of the TB patients was 85.2%. The treatment success rate of the TB patients increased from 80.5% in September 2008-August 2009 to 84.8% in September 2012-May 2013. Tuberculosis type, age, residence and year of treatment were significantly associated with unsuccessful treatment outcome. The risk of unsuccessful outcome was significantly higher among TB patients from rural areas (AOR = 1.63, 95% CI: 1.21-2.20 compared to their urban counterparts. Unsuccessful treatment outcome was also observed in PTB- patients (AOR = 1.77, 95% CI: 1.26-2.50 and EPTB (AOR = 2.07, 95% CI: 1.28-3.37 compared to the PTB+ patients. In conclusion, it appears that DOTS have improved treatment success in the hospital during five years. Regular follow-up of patients with poor treatment outcome and provision of health information on TB treatment to

  3. Influence of the Portuguese Bend landslide on the character of the effluent-affected sediment deposit, Palos Verdes margin, southern California

    Science.gov (United States)

    Kayen, R.E.; Lee, H.J.; Hein, J.R.

    2002-01-01

    Historic accretion of sediment on the Palos Verdes margin off Los Angeles County, CA, is dominated by two sources, effluent from Whites Point outfall and sediment eroded from the toe of Portuguese Bend landslide. In this paper, we document the recent history of sedimentation from these non-marine sources from 1937 until the late 1990s, and attempt to estimate the amount of material preserved on the shelf. Toward that end, we characterized offshore sediment by physical and geotechnical testing, using non-destructive gamma-ray whole-core logging techniques and conventional geotechnical strength tests, and X-ray diffraction. Results are reported within a geographic information system framework that allows for: (1) the evaluation of the spatial variability of the measured properties, and (2) assessment of the influence of these properties on processes affecting the effluent-affected Sediment layer. In the inner shelf, material eroded by wave action from the toe of the Portuguese Bend landslide since 1956 has contributed 5.7-9.4 million metric tons (Mmt) of sediment, from a total eroded mass of 12.1 Mmt. A lesser fraction (???2.7Mmt) of sediment is incorporated into the mid- and outer-shelf effluent-affected sediment layer. Evidence from X-ray diffractograms clearly indicates that landslide material has mixed with the mid- and outer-shelf effluent. From 1937-1987, it is estimated that 3.8 Mmt of solid anthropogenic effluent was discharged into the water column and onto the Palos Verdes Shelf.

  4. Post-irradiation tensile, creep and creep rupture data of DIN 1.4948 steel weld metal, heat-affected zones and welded joints of the SNR-300 permanent primary structures

    International Nuclear Information System (INIS)

    DIN 1.4948 (Type 304) austenitic stainless steel has been tested for use in the SNR-300. Full weld metal specimens from a wide groove weld have been subjected to tensile and creep tests in as-deposited and stress-relieved condition. Heat-affected zones were simulated in full size standard specimens by subjecting raw cylinders to temperature cycles representative for the heat-affected zone (HAZ). The welded joints were taken from qualification welds from components, such as reactor vessel and core shield, built for the SNR-300. Half of all the specimens were irradiated in the HFR, Petten at 823 K submerged in sodium to a total neutron fluence, representative for end of life fluences of SNR-300 reactor vessel and shield tank. The tensile and creep properties of as-deposited and stress-relieved weld metal are not affected by the neutron irradiation. The stress relief treatment of 3 h at 1175 K improves both tensile and creep ductility, without affecting strength too much, by reducing the dislocation density in weld metal and HAZ and coarsening the carbides in weld metal. The HAZ shows a pronounced decrease in post-irradiation tensile ductility, strength, creep strength and ductility. Ductility of weld metal can be improved by stress-relieving and adapting the chemical composition of the filler metal. In order to prevent the HAZ to become the weakest link of a welded joint after irradiation grain growth and boron precipitation on grain boundaries must be suppressed. Low heat input welding techniques such as electron beam welding and automated gas metal arc welding might offer a solution for HAZ post-irradiation embrittlement. 144 figs.; 20 refs.; 45 tables

  5. How does the selection of landscape classification schemes affect the spatial pattern of natural landscapes? An assessment on a coastal wetland site in southern Italy.

    Science.gov (United States)

    Tomaselli, V; Veronico, G; Sciandrello, S; Blonda, P

    2016-06-01

    It is widely known that thematic resolution affects spatial pattern and landscape metrics performances. In literature, data dealing with this issue usually refer to a specific class scheme with its thematic levels. In this paper, the effects of different land cover (LC) and habitat classification schemes on the spatial pattern of a coastal landscape were compared. One of the largest components of the Mediterranean wetland system was considered as the study site, and different schemes widely used in the EU were selected and harmonized with a common thematic resolution, suitable for habitat discrimination and monitoring. For each scheme, a thematic map was produced and, for each map, 28 landscape metrics were calculated. The landscape composition, already in terms of number of classes, class area, and number of patches, changes significantly among different classification schemes. Landscape complexity varies according to the class scheme considered and its underlying semantics, depending on how the different types aggregate or split when changing class scheme. Results confirm that the selection of a specific class scheme affects the spatial pattern of the derived landscapes and consequently the landscape metrics, especially at class level. Moreover, among the classification schemes considered, EUNIS seems to be the best choice for a comprehensive representation of both natural and anthropogenic classes.

  6. Cold seep and oxygen minimum zone associated sources of margin heterogeneity affect benthic assemblages, diversity and nutrition at the Cascadian margin (NE Pacific Ocean)

    Science.gov (United States)

    Guilini, Katja; Levin, Lisa A.; Vanreusel, Ann

    2012-04-01

    Hydrate Ridge (HR), located on the northeastern Pacific margin off Oregon, is characterized by the presence of outcropping hydrates and active methane seepage. Additionally, permanent low oxygen conditions overlay the benthic realm. This study evaluated the relative influence of both seepage and oxygen minima as sources of habitat heterogeneity and potential stress-inducing features on the bathyal metazoan benthos (primarily nematodes) at three different seep and non-seep HR locations, exposed to decreasing bottom-water oxygen concentrations with increasing water depth. The nematode seep communities at HR exhibited low diversity with dominance of only one or two genera (Daptonema and Metadesmolaimus), elevated average individual biomass and δ13C evidence for strong dependance on chemosynthesis-derived carbon, resembling deep-sea seeps worldwide. Although the HR seep habitats harbored a distinct nematode community like in other known seep communities, they differed from deep-sea seeps in well-oxygenated waters based on that they shared the dominant genera with the surrounding non-seep sediments overlain by oxygen-deficient bottom water. The homogenizing effect of the oxygen minimum zone on the seep nematode assemblages and surrounding sediments was constant with increasing water depth and concomitant greater oxygen-deficiency, resulting in a loss of habitat heterogeneity.

  7. Birth of two volcanic islands in the southern Red Sea

    KAUST Repository

    Xu, Wenbin

    2015-05-26

    Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011–2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north–south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice.

  8. 毛乌素沙地、腾格里沙漠南缘带土地利用与气候变化关系研究——以宁夏中部为例%Relationship Between Land Use and the Climate Change in the Southern Marginal Zones of the Tengger Desert and Mu Us Desert —A Case Study in Central of Ningxia

    Institute of Scientific and Technical Information of China (English)

    贾科利; 张俊华; 郭占军

    2011-01-01

    利用1978年MSS及1987,1996和2007年Landsat TM/ETM遥感影像,借助GIS技术,对腾格里沙漠与毛乌素沙地南缘地带土地利用与气候变化的响应关系进行了研究.结果表明,研究区年均温升高,降水量减少,气候趋于暖干化,土地利用开发程度差异显著,表现出30 a来,毛乌素沙地南缘土地利用开发强度整体较大,高于腾格里沙漠南缘地带,在变化速度上,毛乌素沙地高于腾格里沙漠南缘地区.%By using the MSS image in 1978 and Landsat TM/ETM images in 1987, 1996, 2007 with the help of GIS, the relationship between land use and the climate change in the southern marginal zones of Tengger desert and Mu Us desert in central of Ningxia from 1978 to 2007 were analyzed. The results showed that under the conditions that the climate in north China trends to warming and drying, especially,under the control of the water and heat conditions, the degree of land use difference was significant in the southern marginal zones of Tengger desert and Mu Us desert. The land use level in the studying area was generally increased in the nearly past 30 years. But the land use level in the southern marginal zones of Mu Us desert was higher than that in the southern marginal zones of Tengger desert, as well as the speed of land use change in the southern marginal zones of Mu Us desert.

  9. Are population dynamics of shorebirds affected by El Niño/Southern Oscillation (ENSO) while on their non-breeding grounds in Ecuador?

    Science.gov (United States)

    O'Hara, Patrick D.; Haase, Ben J. M.; Elner, Robert W.; Smith, Barry D.; Kenyon, Jamie K.

    2007-08-01

    Declines in avian populations are a global concern, particularly for species that migrate between Arctic-temperate and tropical locations. Long-term population studies offer opportunities to detect and document ecological effects attributable to long-term climatic cycles such as the El Niño/Southern Oscillation (ENSO). In this study, we report possible population-level effects of such climatic cycles on shorebird species that use two non-breeding season sites in Ecuador (Santa Elena peninsula area, near La Libertad). During our 9-year study period (1991/1992-1999/2000), there was a particularly strong ENSO warm phase event during 1997/1998. Population trend data for three species of shorebird, Western Sandpipers ( Calidris mauri), Semipalmated Sandpipers ( C. pusilla), and Least Sandpipers ( C. minutilla), indicated abundances generally declined during the 1990s, but there was an increase in the proportion of first-year birds and their abundance in the years following the 1997/1998 ENSO warm phase. There was some support for variation in apparent survivorship associated with the onset of the ENSO warm phase event in our population models, based on capture-mark-recapture data. Following the 1997/1998 ENSO event onset, individuals for all three species were significantly lighter during the non-breeding season ( F1,3789 = 6.6, p = 0.01). Least-squares mean mass (controlling for size, sex and day of capture) for first-year birds dropped significantly more than for adults following ENSO (first-year mass loss = 0.69 ± 0.12 g; adult mass loss = 0.34 ± 0.11 g, F1,3789 = 5.31, p = 0.021), and least-squares mean mass dropped most during the period when sandpipers prepare for northward migration by gaining mass and moulting into breeding plumage. Least Sandpipers may have declined the most in mean mass following ENSO (0.76 ± 0.19 g), whereas Semipalmated Sandpipers were 0.52 ± 0.12 g lighter, and Western Sandpipers 0.40 ± 0.13 g lighter, but overall variation among

  10. Bioturbation, geochemistry and geotechnics of sediments affected by the oxygen minimum zone on the Oman continental slope and abyssal plain, Arabian Sea

    Science.gov (United States)

    Meadows, Azra; Meadows, Peter S.; West, Fraser J. C.; Murray, John M. H.

    2000-01-01

    We investigate the way the oxygen minimum zone (OMZ) alters interactions between bioturbation and sediment geochemistry, and geotechnical properties. Sediments are compared within and below the OMZ on the Oman continental slope and adjacent abyssal plain during the post monsoonal autumn season. Quantitative measurements were made of Eh and pH, of total organic matter (TOM) and carbonate, of water content and shear strength, and of bioturbation structures in vertical profiles of subcores taken from spade-box core samples. The OMZ stations had distinctively low redox conditions and high carbonate content, and different geotechnical properties and different bioturbation structures than stations below the OMZ on the abyssal plain. These differences are related to the degree of anoxia and to water depth. Within the OMZ, Eh, pH and carbonate increased with water depth, and TOM and water content decreased. We also noted the presence of subsurface sediment heterogeneity on the continental slope within the OMZ. In the OMZ, Eh, water content and bioturbation decreased with increasing sediment depth. There was a slight decrease in pH in the top 5 cm at all stations. Shear strength nearly always increased with increasing sediment depth. At each water depth correlations show down-core trends in these parameters, while across all water depths correlations were significant at deeper sediment depths (20-30 cm). An Eh-pH diagram identified two water-depth groupings: 391-1008 and 1265-3396 m. Cluster analysis showed the upper and lower sediment depths form separate clusters, the break occurring at 4-7.5 cm; while there are also distinct clusters related to water depth. We relate our results to bottom-water oxygen concentrations reported by other investigators, and to regional-scale geochemical processes.

  11. Louisiana Coastal Zone Boundary, Geographic NAD83, LDNR (1998)[coastal_zone_boundary_LDNR_1998

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a polygon dataset representing the extent of the LDNR regulatory area defined as the Louisiana Coastal Zone. This area comprises a band across the southern...

  12. Evaluation of energy, protein, and selected micronutrient density of homemade complementary foods consumed by children between 6 months and 23 months in food insecure woredas of Wolayita zone, Southern Ethiopia

    Directory of Open Access Journals (Sweden)

    Abeshu MA

    2016-09-01

    Full Text Available Motuma Adimasu Abeshu,1,2 Abdulaziz Adish,3 Gulelat D Haki,4 Azeb Lelisa,5 Bekesho Geleta6 1John Snow, Inc, 2Addis Ababa University, Center for Food Science and Nutrition, 3Micronutrient Initiative Africa, Addis Ababa, Ethiopia; 4Department of Food Science and Technology, University of Botswana, Gaborone, Botswana; 5Micronutrient Initiative Ethiopia, 6Ethiopian Public Health Institute, Addis Ababa, Ethiopia Abstract: Complementary feeding should be timely, adequate, and given in a way that is appropriate for the age of the child, applying responsive feeding to fill the gap between what is provided by breastfeeding and the total nutritional requirements of the infant. The purpose of this study was to assess nutrient composition and evaluate adequacy of observed nutrient densities (energy, protein, calcium [Ca], iron [Fe], and zinc [Zn] in homemade complementary foods for children of age 6–23 months, in comparison to the desired levels in food insecure woredas of the Wolayita zone, Southern Ethiopia. A cross-sectional weighed food record method was used to assess the energy and micronutrient compositions of homemade complementary foods and evaluate adequacy of observed nutrient densities in relation to the desired levels. Multistage sampling was used to locate the children. Observation and measurement of complementary food preparations throughout the day was made. Representative portions from the diets were sampled for further laboratory analysis and to evaluate adequacy of observed nutrient levels. More than 20 different complementary food types (mostly an extension of family foods prepared from various food items were observed. Dietary diversity of the foods was very poor. The average dietary diversity score was only 2.54, while animal-source foods and vitamin A-rich fruits and vegetables were virtually absent. The energy and protein compositions of the diets, however, were sufficient. Energy density of 0.92 kcal/g, 1.24 kcal/g, and 1.41

  13. Potential and use of archaeological and historical data in the coastal zone of the southern North Sea in a reconstruction of the sea level curve of the last 3000 years: results of a case study

    NARCIS (Netherlands)

    Kluiving, S.J.; Lascaris, M.A.; de Kraker, A.M.J.; Renes, H.; Borger, G.J.; Soetens, S.A.

    2013-01-01

    This paper demonstrates that methodologies from various disciplines can be utilised to explain the coastal development of the southern North Sea during the last 3000 years. The potential and uses of archaeological data are tested against the applicability of delivering data for reconstructing sea le

  14. Geochemistry of the Peramora Mélange and Pulo do Lobo schist: geochemical investigation and tectonic interpretation of mafic mélange in the Pangean suture zone, Southern Iberia

    Science.gov (United States)

    Dahn, Dustin R. L.; Braid, James A.; Murphy, J. Brendan; Quesada, Cecilio; Dupuis, Nicole; McFarlane, Christopher R. M.

    2014-07-01

    The Peramora Mélange is part of an accretionary complex between the South Portuguese Zone (a fragment of Laurussia) and the Ossa Morena Zone (para-autochthonous Gondwana) and is an expression of the Pangean suture zone in southwestern Iberia. The suture zone is characterized by fault-bounded units of metasedimentary rocks, mélanges, and mafic complexes. Detailed geologic mapping of the Peramora Mélange reveals a complex pattern of imbricated schists and mafic block-in-matrix mélanges. Geochemical signatures of the Pulo do Lobo schist (PDL) are consistent with derivation from both mafic and continental sources. The mafic block-in-matrix mélange displays normal mid-ocean ridge basalt (NMORB) geochemical signature, juvenile Sm-Nd isotopic compositions, and a range of zircon ages similar to those observed in the PDL, suggesting a sedimentary component. Taken together, these data suggest a complex tectonic history characterized by erosion of a NMORB source, mélange formation, and imbrication during underplating occurring during the final stages of continent-continent collision.

  15. Growth dynamics of the seagrass Zostera japonica at its upper and lower distributional limits in the intertidal zone

    Science.gov (United States)

    Kim, Jong-Hyeob; Kim, Seung Hyeon; Kim, Young Kyun; Park, Jung-Im; Lee, Kun-Seop

    2016-06-01

    The seagrass Zostera japonica occurs mainly in the intertidal zone and is thus exposed to widely varying environmental conditions affecting its growth and distribution compared to subtidal seagrasses. The growth dynamics of Z. japonica at its upper and lower distributional limits in the intertidal zone were investigated in Koje Bay on the southern coast of Korea to examine the environmental stresses and limiting factors on the growth of intertidal seagrasses. The shoot density and morphology, biomass, and leaf productivity of Z. japonica were measured in relation to coincident measurements of environmental factors at its upper and lower distributional limits and in an intermediate zone of the intertidal area. The mean exposure time to the atmosphere during low tide in the upper intertidal zone was approximately 1.5- and 1.9-fold longer than that in the intermediate and lower intertidal zones, respectively. Shoot density and biomass were significantly higher in the intermediate zone than at the upper and lower distributional limits. Longer emersion leading to a various of environmental stresses appeared to reduce Z. japonica growth in the upper intertidal zone, whereas interspecific competitive interactions related to irradiance seemed to affect Z. japonica growth in the lower intertidal zone. Shoot size, density, biomass, and leaf productivity were lower in the upper than in the lower zone, implying that emersion-associated stresses in the upper zone had a greater detrimental effect on Z. japonica growth than did stresses occurring in the lower zone. The productivity of Z. japonica showed strong positive correlations with air and water temperature, suggesting enhancement of Z. japonica production at higher temperatures. Thus, the predicted increases in air and water temperature associated with global climate change might have positive effects on the growth and extension in distributional range of this species.

  16. Effect of welding thermal cycles on the structure and properties of simulated heat-affected zone areas in X10CrMoVNb9-1 (T91) steel at a state after 100,000 h of operation

    International Nuclear Information System (INIS)

    The article presents results of structural tests (light, scanning electron and scanning transmission electron microscopy) of X10CrMoVNb9-1 (T91) creep-resisting steel after approximately 100,000 h of operation. It was ascertained that the parent metal of T91 steel is characterized by the microstructure of tempered martensite with M23C6 carbide precipitates and few dispersive precipitates of MX-type niobium and vanadium carbonitrides. The most inconvenient change in T91 steel precipitate morphology due to long-term operation is the appearance of the Laves Fe2Mo phase which along with M23C6 carbide particles forms elongated blocks and conglomerates on grain boundaries. The article also presents results of tests related to the effect of simulated welding thermal cycles on selected properties of X10CrMoVNb9-1 (T91) grade steel at a state after approximately 100,000 h of operation. The tests involved the determination of the chemical composition of the steel tested as well as impact tests, hardness measurements and microscopic metallographic examination (based on light microscopy) of simulated heat-affected zone (HAZ) areas for a cooling time (t8/5) restricted within a range between 3 s and 120 s, with and without heat treatment. The tests revealed that, among other results, hardness values of simulated HAZ areas in X10CrMoVNb9-1 (T91) steel do not guarantee cold crack safety of the steel at the state without additional heat treatment. It was also observed that simulated welding thermal cycles of cooling times t8/5=3, 12, 60 and 120 s do not significantly affect the toughness and hardness of simulated HAZ areas of the steel tested

  17. Effect of welding thermal cycles on the structure and properties of simulated heat-affected zone areas in X10CrMoVNb9-1 (T91) steel at a state after 100,000 h of operation

    Energy Technology Data Exchange (ETDEWEB)

    Łomozik, Mirosław, E-mail: miroslaw.lomozik@is.gliwice.pl [Instytut Spawalnictwa, Testing of Materials Weldability and Welded Constructions Department, 44-100 Gliwice, Bł. Czesława 16-18 (Poland); Hernas, Adam, E-mail: adam.hernas@polsl.pl [Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, 40-019 Katowice, Krasińskiego 8 str. (Poland); Zeman, Marian L., E-mail: marian.zeman@is.gliwice.pl [Instytut Spawalnictwa, Testing of Materials Weldability and Welded Constructions Department, 44-100 Gliwice, Bł. Czesława 16-18 (Poland)

    2015-06-18

    The article presents results of structural tests (light, scanning electron and scanning transmission electron microscopy) of X10CrMoVNb9-1 (T91) creep-resisting steel after approximately 100,000 h of operation. It was ascertained that the parent metal of T91 steel is characterized by the microstructure of tempered martensite with M{sub 23}C{sub 6} carbide precipitates and few dispersive precipitates of MX-type niobium and vanadium carbonitrides. The most inconvenient change in T91 steel precipitate morphology due to long-term operation is the appearance of the Laves Fe{sub 2}Mo phase which along with M{sub 23}C{sub 6} carbide particles forms elongated blocks and conglomerates on grain boundaries. The article also presents results of tests related to the effect of simulated welding thermal cycles on selected properties of X10CrMoVNb9-1 (T91) grade steel at a state after approximately 100,000 h of operation. The tests involved the determination of the chemical composition of the steel tested as well as impact tests, hardness measurements and microscopic metallographic examination (based on light microscopy) of simulated heat-affected zone (HAZ) areas for a cooling time (t{sub 8/5}) restricted within a range between 3 s and 120 s, with and without heat treatment. The tests revealed that, among other results, hardness values of simulated HAZ areas in X10CrMoVNb9-1 (T91) steel do not guarantee cold crack safety of the steel at the state without additional heat treatment. It was also observed that simulated welding thermal cycles of cooling times t{sub 8/5}=3, 12, 60 and 120 s do not significantly affect the toughness and hardness of simulated HAZ areas of the steel tested.

  18. Effects of alloying elements on fracture toughness in the transition temperature region of base metals and simulated heat-affected zones of Mn-Mo-Ni low-alloy steels

    Science.gov (United States)

    Kim, Sangho; Im, Young-Roc; Lee, Sunghak; Lee, Hu-Chul; Kim, Sung-Joon; Hong, Jun Hwa

    2004-07-01

    This study is concerned with the effects of alloying elements on fracture toughness in the transition temperature region of base metals and heat-affected zones (HAZs) of Mn-Mo-Ni low-alloy steels. Three kinds of steels whose compositions were varied from the composition specification of SA 508 steel (grade 3) were fabricated by vacuum-induction melting and heat treatment, and their fracture toughness was examined using an ASTM E1921 standard test method. In the steels that have decreased C and increased Mo and Ni content, the number of fine M2C carbides was greatly increased and the number of coarse M3C carbides was decreased, thereby leading to the simultaneous improvement of tensile properties and fracture toughness. Brittle martensite-austenite (M-A) constituents were also formed in these steels during cooling, but did not deteriorate fracture toughness because they were decomposed to ferrite and fine carbides after tempering. Their simulated HAZs also had sufficient impact toughness after postweld heat treatment. These findings indicated that the reduction in C content to inhibit the formation of coarse cementite and to improve toughness and the increase in Mo and Ni to prevent the reduction in hardenability and to precipitate fine M2C carbides were useful ways to improve simultaneously the tensile and fracture properties of the HAZs as well as the base metals.

  19. Effect of Heat Input on Microstructure Evolution and Mechanical Properties in the Weld Heat-Affected Zone of 9Cr-2W-VTa Reduced Activation Ferritic-Martensitic Steel for Fusion Reactor

    Science.gov (United States)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Kim, Hyoung Chan

    2015-01-01

    The phase transformation and mechanical properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic steel were explored. The samples for HAZs were prepared using a Gleeble simulator at different heat inputs. The base steel consisted of tempered martensite and carbides through quenching and tempering treatment, whereas the HAZs consisted of martensite, δ-ferrite, and a small volume of autotempered martensite. The prior austenite grain size, lath width of martensite, and δ-ferrite fraction in the HAZs increased with increase in the heat input. The mechanical properties were evaluated using Vickers hardness and Charpy V-notch impact test. The Vickers hardness in the HAZs was higher than that in the base steel but did not change noticeably with increase in the heat input. The HAZs showed poor impact property due to the formation of martensite and δ-ferrite as compared to the base steel. In addition, the impact property of the HAZs deteriorated more with the increase in the heat input. Post weld heat treatment contributed to improve the impact property of the HAZs through the formation of tempered martensite, but the impact property of the HAZs remained lower than that of base steel.

  20. Cadmium isotope variations in the Southern Ocean

    NARCIS (Netherlands)

    Xue, Z.; Rehkämper, M.; Horner, T.J.; Abouchami, W.; Middag, R.; van de Flierd, T.; de Baar, H.J.W.

    2013-01-01

    Cadmium concentrations and isotope compositions were determined for 47 seawater samples from the high nutrient low chlorophyll (HNLC) zone of the Atlantic sector of the Southern Ocean. The samples include 13 surface waters from a transect of the Weddell Gyre and 3 depth profiles from the Weddell Sea

  1. Relationship between crystallographic structure of the Ti2O3/MnS complex inclusion and microstructure in the heat-affected zone (HAZ) in steel processed by oxide metallurgy route and impact toughness

    International Nuclear Information System (INIS)

    A new method based on electron back scattered diffraction (EBSD) is proposed to determine the structure of titanium oxide/MnS complex inclusion which induced the formation of intragranular acicular ferrite (IAF) in heat-affected zone (HAZ) in steel processed by oxide metallurgy route. It was found that the complex inclusion was Ti2O3/MnS, the orientation relationship between Ti2O3 and MnS was also examined, and the crystallographic orientation relationship among IAF, Ti2O3/MnS complex inclusion, austenite, bainite formed at lower temperature is researched systematically. It was observed that MnS precipitated on Ti2O3 at specific habit plane and direction and MnS had a specific orientation relationship ((0001) Ti2O3//(111) MnS), <10–10> Ti2O3//<110> MnS) with respect to Ti2O3. Intragranular acicular ferrite (IAF) nucleated on MnS part of the Ti2O3/MnS complex inclusion had no specific orientation relationship with MnS. IAF and the surrounding bainite had different Bain groups, so that there was an increase in high angle boundaries, which was beneficial for the toughness of HAZ. - Highlights: • The inclusion of TiOx/MnS that induced IAF formation is identified to be Ti2O3/MnS. • The inclusion is identified based on electron back scattered diffraction (EBSD). • MnS and Ti2O3 had specific orientation relationship of Ti2O3/MnS complex inclusion. • The IAFs formed on the same inclusion tend to be in one Bain group. • IAF and the surrounding bainite tend to be in different Bain groups

  2. Pan-European Chikungunya surveillance: designing risk stratified surveillance zones.

    Science.gov (United States)

    Tilston, Natasha; Skelly, Chris; Weinstein, Phil

    2009-01-01

    The first documented transmission of Chikungunya within Europe took place in Italy during the summer of 2007. Chikungunya, a viral infection affecting millions of people across Africa and Asia, can be debilitating and no prophylactic treatment exists. Although imported cases are reported frequently across Europe, 2007 was the first confirmed European outbreak and available evidence suggests that Aedes albopictus was the vector responsible and the index case was a visitor from India. This paper proposed pan-European surveillance zones for Chikungunya, based on the climatic conditions necessary for vector activity and viral transmission. Pan-European surveillance provides the best hope for an early-warning of outbreaks, because national boundaries do not play a role in defining the risk of this new vector borne disease threat. A review of climates, where Chikungunya has been active, was used to inform the delineation of three pan-European surveillance zones. These vary in size each month across the June-September period of greatest risk. The zones stretch across southern Europe from Portugal to Turkey. Although the focus of this study was to define the geography of potential surveillance zones based on the climatic limits on the vector and virus, a preliminary examination of inward bound airline passengers was also undertaken. This indicated that France and Italy are likely to be at greater risk due to the number of visitors they receive from Chikungunya active regions, principally viraemic visitors from India. Therefore this study represents a first attempt at creating risk stratified surveillance zones, which we believe could be usefully refined with the use of higher resolution climate data and more complete air travel data. PMID:19878588

  3. Pan-European Chikungunya surveillance: designing risk stratified surveillance zones

    Directory of Open Access Journals (Sweden)

    Skelly Chris

    2009-10-01

    Full Text Available Abstract The first documented transmission of Chikungunya within Europe took place in Italy during the summer of 2007. Chikungunya, a viral infection affecting millions of people across Africa and Asia, can be debilitating and no prophylactic treatment exists. Although imported cases are reported frequently across Europe, 2007 was the first confirmed European outbreak and available evidence suggests that Aedes albopictus was the vector responsible and the index case was a visitor from India. This paper proposed pan-European surveillance zones for Chikungunya, based on the climatic conditions necessary for vector activity and viral transmission. Pan-European surveillance provides the best hope for an early-warning of outbreaks, because national boundaries do not play a role in defining the risk of this new vector borne disease threat. A review of climates, where Chikungunya has been active, was used to inform the delineation of three pan-European surveillance zones. These vary in size each month across the June-September period of greatest risk. The zones stretch across southern Europe from Portugal to Turkey. Although the focus of this study was to define the geography of potential surveillance zones based on the climatic limits on the vector and virus, a preliminary examination of inward bound airline passengers was also undertaken. This indicated that France and Italy are likely to be at greater risk due to the number of visitors they receive from Chikungunya active regions, principally viraemic visitors from India. Therefore this study represents a first attempt at creating risk stratified surveillance zones, which we believe could be usefully refined with the use of higher resolution climate data and more complete air travel data.

  4. Gingiva biotype affects the soft tissue esthetic outcomes of immediate implant in the asthetic zone%在美学区即刻种植中牙龈生物型对红色美学效果的影响

    Institute of Scientific and Technical Information of China (English)

    王文君; 刘聪慧

    2015-01-01

    Objective:To analysis the influence of gingival biotype on pink esthetic of single-tooth immediate implant restorations in the anterior maxilla. Methods: 32 patients with single tooth immediate implant in the aesthetic zone were included. All patients were followed up 1 year after implant restorations, and divided into three groups (thin, compromised and thick gingival biotype) with different gingival biotypes by using periodontal probing. An intra-oral digital photograph was obtained and pink esthetic score (PES) were calculated for three groups. A non-parametric statistical analysis of the data was performed by software SPSS11.0. Results:There was statistical differences in PES between compromised and thick (P0.05). Conclusion: the gingival biotype may affect the soft tissue esthetic out-comes of single-tooth implant restorations in the asthetic zone, especially the mesial and distal papilla of the implants.%目的:分析在上前牙区单颗即刻种植治疗中,不同牙龈生物型对种植的红色美学效果影响。方法:选择上颌前牙区单颗牙即刻种植修复的患者32例,在种植修复完成一年后复查。用牙周探诊法判断牙龈生物型进行分组(薄型、中间型、厚型),每组患牙进行口内像拍照记录,做红色美学指数分析,采用SPSS11.0统计软件将结果进行非参数统计学分析。结果:红色美学指数总分比较时,中-厚之间有差别(P<0.05),薄-厚之间差别更明显(P<0.01),近中和远中龈乳头评分时,薄-厚之间有差别(P<0.05),其它各指标的差异无统计学意义(P>0.05)。结论:不同牙龈生物型患者前牙区即刻种植治疗时,红色美学效果不同,尤其是近远中牙龈乳头的美学效果区别明显。

  5. 旅游影响区等级划分及旅游影响指标的分析%Grade Classification of Tourism Affected Zone and Analysis of Relevant Indicators

    Institute of Scientific and Technical Information of China (English)

    郭秀玲; 上官铁梁

    2012-01-01

    The Luya Mountain Nature Reserve,a well-known tourism spots,is in the northern part of Luliang Mountains in Shanxi Province.It was designated as the national AAAA level scenic area in 2010.The mountain has abundant species,various vegetation types and highly diversified habitats.This thesis selected one of the typical tourist attractions in Luya Mountain Nature Reserve,namely Bingkouwa to study the impacts of tourism on forest vegetations through the quantitative ecological methods including plant classification,principal component analysis and correlation analysis.The major studying results are as follows: 1) The TWINSPAN classification divided the area into six impact zones by the extent of tourism influences,reflecting the alternations in spatial pattern by tourism activities,where the trails were used as the axis.2) The correlation analysis revealed significant relationships among 3 out of 12 pairs of tourism indicators,namely remove stumps influence coefficient vs.trail distance,waste impact coefficient vs.remove stumps influence coefficient,and waste impact coefficient vs.trail distance.Meanwhile the H′ and slope were found well correlated.3) The PCA analysis of 12 impact indicators showed five principal components which were closely related with seven impact indicators,accounting for 81.88% of the comprehensive information.The results of tourism affected zone level division by seven tourism impact indicators and 12 tourism impact indicators were the same.This simplifies the selection for tourism impact indicators for application purpose.%采用TWINSPAN分类法,根据旅游对森林植被影响程度,划分为6个旅游等级影响区,反映了以游径为轴线的旅游影响水平空间格局变化规律;对12个旅游影响指标相关分析表明,有3对旅游影响指标间存在显著或极显著关系。其中剔除树桩影响系数和游径距离为极显著相关,旅游垃圾影响系数和剔除树桩影响系数、旅游垃圾

  6. Ecología trófica de Girella laevifrons (Pisces: Kyphosidae en zonas intermareales rocosas del norte de Chile afectadas y no afectadas por contaminantes derivados de la minería del cobre Trophic ecology of Girella laevifrons (Pisces: Kyphosidae in rocky intertidal zones of northern Chile affected an non-affected by copper mine tailings

    Directory of Open Access Journals (Sweden)

    JOSE MIGUEL FARIÑA

    2000-03-01

    Full Text Available La zonas intermareales de localidades de la costa norte de Chile afectadas por contaminantes derivados de la minería del cobre, presentan una diversidad de especies sésiles menor que las localidades no afectadas. Girella laevifrons es un pez altamente representado en zonas intermareales rocosas del norte de Chile. En el presente trabajo se analiza y compara la ecología trófica de esta especie, en relación con las diferencias en la composición de especies sésiles de sitios contaminados y no contaminados. Los resultados muestran diferencias significativas en la composición trófica de los ejemplares presentes en los sitios afectados y no afectados. Dentro de los sitios afectados, se observan diferencias en los tamaños y en las concentraciones de cobre corporales, las cuales pueden estar relacionadas directamente con la disponibilidad de alimento e indirectamente con interacciones con otros organismos intermarealesThe intertidal zone at several sites of the northern Chilean coast affected by copper mine tailings, shows a lower diversity of sessile species than the non-affected ones. Girella laevifrons is a fish highly represented in rocky intertidal shores of these sites. In this study we analized and compared, the dietary composition of this species and its relation with the intertidal sessile assemblages of contaminated and non-contaminated sites. The results show significant differences in the dietary composition of the fishes occurring in contaminated and non-contaminated sites. Within the contaminated sites, the differences in body sizes and in the body concentrations of copper could be related directly to the food availability and indirectly to the interactions with other intertidal species

  7. Atributos químicos do solo e produtividade de videiras alterados pelo manejo de coberturas verdes na Serra Gaúcha Soil chemical properties and grapevine yield affected by cover crop management in Serra Gaucha, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Jaqueline Dalla Rosa

    2009-02-01

    Full Text Available O manejo do solo pode interferir na disponibilidade de nutrientes e na produtividade de frutos. O objetivo deste estudo foi avaliar o efeito de formas de manejo da fitomassa de diferentes espécies de plantas de cobertura verde sobre características químicas do solo, relacionadas à matéria orgânica e à disponibilidade de nutrientes, e sobre a produtividade de uva. O experimento foi realizado na Embrapa Uva e Vinho, em Bento Gonçalves, RS, sobre um Cambissolo Háplico, num parreiral implantado em 1989, com os cultivares Niágara Branca e Niágara Rosada, no sistema de latada. Os tratamentos testados foram implantados em 2002 e consistiram em três coberturas vegetais: vegetação espontânea, aveia-preta e consórcio de trevo-branco + trevo-vermelho + azevém; e dois sistemas de manejo: dessecado com herbicida e roçado, os quais foram realizados no outono, previamente à ressemeadura das espécies. O delineamento experimental foi de blocos ao acaso com três repetições. Os atributos químicos indicadores da acidez e da disponibilidade de nutrientes no solo foram pouco influenciados pelas espécies de cobertura. A dessecação das plantas aumentou os teores de Ca e Mg trocáveis, P disponível e C orgânico total em relação ao manejo roçado. A produtividade de uva nas safras de 2004 e 2006 foi baixa em relação ao potencial dos cultivares, possivelmente por restrições climáticas, contudo foi maior quando se utilizou a aveia como planta de cobertura do que com o consórcio de plantas.Soil management can have effects on nutrient availability and fruit yield. The objective of this study was to evaluate the effect of phytomass management forms of different cover crop species on soil chemical properties related to organic matter, nutrient availability, and on grapevine yields. The experiment was carried out in Embrapa Uva e Vinho, in Bento Gonçalves, RS, in Southern Brazil, on a Haplic Cambissol, in a vineyard established in 1989

  8. 热处理对低活马氏体钢焊接热影响区的影响%Effects of Heat Treatment on CLAM Steel Welding Heat Affected Zone

    Institute of Scientific and Technical Information of China (English)

    沈政; 陈希章; 茅奕舒; 周建忠

    2012-01-01

    Referring to the actual welding process, die thermal simulation technique was used for simulating the thermal cycling of the coarse grained heat affect zone (CGHAZ) of CLAM steel, and then different tempering treatments were preceded on the samples after simulation. Dispersed precipitation of the carbide is found after the tempering treatment. In the same tempering condition, no obvious differences of microstructure was observed among the tested samples; higher heat input before tempering resulted in lower hardness after tempering. In the same thermal cycling condition, higher tempering temperature lead to remarkable increase of grain size and decrease of hardness. The hardness of CGHAZ can be effectively improved by tempering the simulated samples at higher temperature and then it changes to be steady with the continue increasing of temperature. Based on the comprehensive consideration of the effect of tempering process on both the hardness and the grain size of CLAM steel, the tempering temperature is advised to be 760℃~810℃.%采用焊接热模拟技术,参照实际焊接工艺,模拟中国低活化马氏体钢(CALM钢)热影响区粗晶区(CGHAZ)热循环过程,并对热模拟后试样进行不同的回火处理.实验发现,CLAM钢热模拟试样经回火处理,碳化物弥散析出,同样的回火条件下,CLAM钢显微组织差异不明显,回火前较高的热量输入导致回火后硬度值更低;在相同的热循环条件下,较高的回火温度会引起晶粒的显著长大,试样硬度值降低.热模拟试样在较高的温度下回火,可以更为有效地改善CGHAZ区域硬度,随回火的温度的继续升高,试样硬度趋于平稳.综合考虑回火工艺CALM钢硬度值以及晶粒度的影响,推荐回火温度为760~810℃.

  9. Relationship between crystallographic structure of the Ti{sub 2}O{sub 3}/MnS complex inclusion and microstructure in the heat-affected zone (HAZ) in steel processed by oxide metallurgy route and impact toughness

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Zhihui; Liu, Shilong [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Wang, Xuemin, E-mail: wxm@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Shang, Chengjia [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Misra, R.D.K. [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials Research and Innovation, Department of Metallurgical and Materials Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States)

    2015-08-15

    A new method based on electron back scattered diffraction (EBSD) is proposed to determine the structure of titanium oxide/MnS complex inclusion which induced the formation of intragranular acicular ferrite (IAF) in heat-affected zone (HAZ) in steel processed by oxide metallurgy route. It was found that the complex inclusion was Ti{sub 2}O{sub 3}/MnS, the orientation relationship between Ti{sub 2}O{sub 3} and MnS was also examined, and the crystallographic orientation relationship among IAF, Ti{sub 2}O{sub 3}/MnS complex inclusion, austenite, bainite formed at lower temperature is researched systematically. It was observed that MnS precipitated on Ti{sub 2}O{sub 3} at specific habit plane and direction and MnS had a specific orientation relationship ((0001) Ti{sub 2}O{sub 3}//(111) MnS), <10–10> Ti{sub 2}O{sub 3}//<110> MnS) with respect to Ti{sub 2}O{sub 3}. Intragranular acicular ferrite (IAF) nucleated on MnS part of the Ti{sub 2}O{sub 3}/MnS complex inclusion had no specific orientation relationship with MnS. IAF and the surrounding bainite had different Bain groups, so that there was an increase in high angle boundaries, which was beneficial for the toughness of HAZ. - Highlights: • The inclusion of TiO{sub x}/MnS that induced IAF formation is identified to be Ti{sub 2}O{sub 3}/MnS. • The inclusion is identified based on electron back scattered diffraction (EBSD). • MnS and Ti{sub 2}O{sub 3} had specific orientation relationship of Ti{sub 2}O{sub 3}/MnS complex inclusion. • The IAFs formed on the same inclusion tend to be in one Bain group. • IAF and the surrounding bainite tend to be in different Bain groups.

  10. 49 CFR 1105.9 - Coastal Zone Management Act requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Coastal Zone Management Act requirements. 1105.9... ENVIRONMENTAL LAWS § 1105.9 Coastal Zone Management Act requirements. (a) If the proposed action affects land or water uses within a State coastal zone designated pursuant to the Coastal Zone Management Act (16...

  11. The thermal effect of fluid circulation in the subducting crust on slab melting in the Chile subduction zone

    Science.gov (United States)

    Spinelli, Glenn A.; Wada, Ikuko; He, Jiangheng; Perry, Matthew

    2016-01-01

    Fluids released from subducting slabs affect geochemical recycling and melt generation in the mantle wedge. The distribution of slab dehydration and the potential for slab melting are controlled by the composition/hydration of the slab entering a subduction zone and the pressure-temperature path that the slab follows. We examine the potential for along-strike changes in temperatures, fluid release, and slab melting for the subduction zone beneath the southern portion of the Southern Volcanic Zone (SVZ) in south central Chile. Because the age of the Nazca Plate entering the subduction zone decreases from ∼14 Ma north of the Guafo Fracture Zone to ∼6 Ma to the south, a southward warming of the subduction zone has been hypothesized. However, both north and south of Guafo Fracture Zone the geochemical signatures of southern SVZ arc lavas are similar, indicating 3-5 wt.% sediment melt and little to no contribution from melt of subducted basalt or aqueous fluids from subducted crust. We model temperatures in the system, use results of the thermal models and the thermodynamic calculation code Perple_X to estimate the pattern of dehydration-derived fluid release, and examine the potential locations for the onset of melting of the subducting slab. Surface heat flux observations in the region are most consistent with fluid circulation in the high permeability upper oceanic crust redistributing heat. This hydrothermal circulation preferentially cools the hottest parts of the system (i.e. those with the youngest subducting lithosphere). Models including the thermal effects of fluid circulation in the oceanic crust predict melting of the subducting sediment but not the basalt, consistent with the geochemical observations. In contrast, models that do not account for fluid circulation predict melting of both subducting sediment and basalt below the volcanic arc south of Guafo Fracture Zone. In our simulations with the effects of fluid circulation, the onset of sediment

  12. The new data on the seasonal distribution of diatoms in the Southern Baltic coastal lakes as a basis for diatom-based transfer functions to reconstruct past environmental changes in the Baltic coastal zone

    Science.gov (United States)

    Rzodkiewicz, Monika; Szpikowska, Grażyna; Woszczyk, Michał; Suchińska, Anita; Burchardt, Lubomira; Messyasz, Beata

    2016-04-01

    Lakes ecosystems are very sensitive to climate and environment changes. In lake sediments there are preserved remains of plant and animals that lived in the lake and its surroundings in the past. The species composition of past assemblages is a basis for quantitative and qualitative reconstruction of the past environmental changes (climate changes). One of the most commonly used bio-proxy for the reconstruction of lake development are subfossil diatoms which are sensitive to lake water pH, nutrient status, salinity and temperature. In this poster we present the new data from the coastal lakes on the Southern Baltic coast. The main goal of this research was to quantify the relationships between modern diatom assemblages and present-day environmental conditions. These relationships will be used to develop diatom-based transfer functions that will be applied to future studies of environmental change on the Polish Baltic coast. Water samples for diatom and chemical analyses were collected a few times per year between 2012 and 2014 from 12 coastal lakes located along the Polish Baltic coast as well as from the Baltic Sea. We analysed the whole phytoplankton composition. However the special focus was put on diatoms. At each site, a suite of important water quality parameters was collected, including chemical (e.g., chlorides, phosphorous and sulphur) and physical (e.g., Secchi depth) variables. Diatom assemblages from each site were counted and identified to the most specific taxonomic level possible. Diatom data were compiled for comparison to corresponding environmental data and development of indicator models. The results of the analysis show seasonal changes in diatom distribution as well as the chemical and physical water propertieswhich are mainly related to saltwater ingressions to the lakes. Lake Koprowo, Lake Resko Przymorskie, Lake Bukowo and Lake Łebsko are under the constant of seawater influence, which makes them similar to lagoons. In Lake Gardno seawater

  13. Diffuse Crustal Accretion at the Southern Terminus of the Malaguana-Gadao Ridge, Mariana Trough

    Science.gov (United States)

    Sleeper, J. D.; Martinez, F.; Fryer, P. B.

    2014-12-01

    The mode of extension and crustal accretion in backarc basins is strongly affected by proximity to the arc volcanic front. The factor that likely has the strongest control on these processes is mantle water content. At Mid-Ocean Ridges, the small amount of water in the mantle is efficiently extracted into the melt, dehydrating the residual material and increasing the viscosity and strength of the lithosphere. This may aid in focusing melt generated over a broad (~200+ km wide) zone in the mantle toward a narrow zone of crustal accretion ~1-2 km wide. In the near-arc setting, the continuous flux of water into the mantle wedge should oppose lithospheric dehydration and inhibit strengthening of the lithosphere, which may allow deformation, volcanism, and crustal accretion to occur over a broad area instead of along a narrow axis. A possible example of this process can be observed at the southern terminus of the Malaguana-Gadao Ridge, a backarc spreading center in the Southern Mariana Trough, at the southern end of the Izu-Bonin-Mariana convergent margin. The spreading axis, which forms an axial high in this area, abruptly terminates at 143˚20'E, 12˚37'N and is replaced by a broad zone of active volcanism and tectonism characterized by short volcanic ridges, volcanic cones, and low-relief grabens. This study uses deep-towed and ship multibeam sonar, gravity, and magnetics data collected during an early 2012 cruise on R/V Thomas G. Thompson (TN273) along with available geophysical and geochemical data in the Southern Mariana Trough to gain insight into the nature of the diffuse crustal accretion process. Evidence of a similar transition from organized to "disorganized" spreading can also be observed at Valu Fa Ridge in the southern Lau basin and other backarc spreading centers. This suggests that this process is not unique to the Southern Mariana Trough, and may be an important mode of crustal accretion in a variety of backarc settings where there is extension in

  14. Neotectonics of coastal Jeffara (southern Tunisia): State of the art

    Science.gov (United States)

    Ghedhoui, Rim; Deffontaines, Benoît; Rabia, Mohamed Chedly

    2016-04-01

    Helped by the studies and results of previous researchers, we herein study the neotectonic of the coastal Jeffara with the input of numerous 2D reflection seismic profiles onshore, combined with Digital Elevation Model analyses (issued from SRTM) and field works. Acquired and available data were then integrated within a GIS Geodatabase, where Jerba, Zarzis and Jorf appear to be part of a N-S pull-apart basin within a NW-SE transtensive right-lateral major fault zone. Our structural geologic and geomorphologic analyses confirm and prove the presence of NNW-SSE right-lateral en-echelon tension gashes, NW-SE aligned salt diapirs, numerous active folds offsets, en-echelon folds, and so-on… They are associated with this major right-lateral NW-SE transtensive major coastal Jeffara fault zone that affect the Holocene and the Villafranchian deposits. We therefore confirm herein a new structural geodynamic Jeffara model, due to the post Lower Cretaceous northward migration of northern African to the Eurasian plates, this NW-SE transtensive fault zone is interpreted as a part of the southern branch of the eastward Sahel block extrusion toward the free Mediterranean Sea boundary. Therefore this geodynamic movement may explain the presence, offshore, of small elongated NW-SE, N-S and NE-SW transtensive basins and grabens with petroleum interest. To conclude, at the regional scale, the structural geomorphologic approach combined with both field work and 2D reflection seismic profile analyses appear to be an excellent tool to prove and confirm the NW-SE right-lateral transtensive extrusion fault zone of the coastal Jeffara.

  15. Southern Appalachian Regional Seismic Network

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, S.C.C.; Johnston, A.C.; Chiu, J.M. [Memphis State Univ., TN (United States). Center for Earthquake Research and Information

    1994-08-01

    The seismic activity in the southern Appalachian area was monitored by the Southern Appalachian Regional Seismic Network (SARSN) since late 1979 by the Center for Earthquake Research and Information (CERI) at Memphis State University. This network provides good spatial coverage for earthquake locations especially in east Tennessee. The level of activity concentrates more heavily in the Valley and Ridge province of eastern Tennessee, as opposed to the Blue Ridge or Inner Piedmont. The large majority of these events lie between New York - Alabama lineament and the Clingman/Ocoee lineament, magnetic anomalies produced by deep-seated basement structures. Therefore SARSN, even with its wide station spacing, has been able to define the essential first-order seismological characteristics of the Southern Appalachian seismic zone. The focal depths of the southeastern U.S. earthquakes concentrate between 8 and 16 km, occurring principally beneath the Appalachian overthrust. In cross-sectional views, the average seismicity is shallower to the east beneath the Blue Ridge and Piedmont provinces and deeper to the west beneath the Valley and Ridge and the North American craton. Results of recent focal mechanism studies by using the CERI digital earthquake catalog between October, 1986 and December, 1991, indicate that the basement of the Valley and Ridge province is under a horizontal, NE-SW compressive stress. Right-lateral strike-slip faulting on nearly north-south fault planes is preferred because it agrees with the trend of the regional magnetic anomaly pattern.

  16. Climatically driven fluctuations in Southern Ocean ecosystems

    OpenAIRE

    Murphy, Eugene J.; Trathan, Philip N; Watkins, Jon L.; Reid, Keith; Meredith, Michael P.; Forcada, Jaume; Thorpe, Sally E.; Johnston, Nadine M; Rothery, Peter

    2007-01-01

    Determining how climate fluctuations affect ocean ecosystems requires an understanding of how biological and physical processes interact across a wide range of scales. Here we examine the role of physical and biological processes in generating fluctuations in the ecosystem around South Georgia in the South Atlantic sector of the Southern Ocean. Anomalies in sea surface temperature (SST) in the South Pacific sector of the Southern Ocean have previously been shown to be generated through atmosp...

  17. Grey literature revisited : the Southern African perspective

    OpenAIRE

    Moshoeshoe-Chadzingwa, M.M. (ISAS); GreyNet, Grey Literature Network Service

    1994-01-01

    Re-examines grey literature on Southern Africa. Analyzes the material from the actual geographical field of concern to determine the suitable handling approach. Asses the extent to which the politico-economic and technological changes in Southern Africa have affected this literature, in terms of its quantities, subject matter, formats, use. Determines how to instil awareness of the value of grey literature first to sub-regional information scientists who will them promote networking and secon...

  18. Zoning Districts, Zoning, Published in 2002, Freelance.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Zoning Districts dataset, was produced all or in part from Hardcopy Maps information as of 2002. It is described as 'Zoning'. Data by this publisher are often...

  19. Intensity of plant collecting in southern Africa

    Directory of Open Access Journals (Sweden)

    G. E. Gibbs Russell

    1984-12-01

    Full Text Available The intensity of plant collecting in southern Africa is mapped using records from the Pretoria National Herbarium Computerized Information System (PRECIS, For the entire area, over 85% of the quarter degree grid squares have fewer than 100 specimens recorded. Collecting intensities are compared for different countries, biomes and climatic zones. Future field work from the National Herbarium will be concentrated in areas most seriously under-collected.

  20. Recent Study of the Changjiang Fault Zone

    Institute of Scientific and Technical Information of China (English)

    Hou Kangming; Zong Kaihong; Guo Jiangning; Xiong Zhen; Li Limei; Zhou Caixia; Jiang Bo

    2009-01-01

    The Changjiang fault zone, also known as the Mufushan-Jiaoshan fault, is a famous fault located at the southern bank of the Changjiang River, near the Nanjing downtown area. Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area (Nanjing city and the nearby areas), trenching and drilling explorations, classification of Quaternary strata and chronology dating data, this paper provides the most up-to-date results regarding activities of the Changjiang fault zone, including the most recent active time, activity nature, related active parameters, and their relation to seismic activity.

  1. Climate change and wildfire around southern Africa

    Science.gov (United States)

    Kimura, K.

    2013-12-01

    When the climate change in southern Africa is analyzed, the effects of rainfall by Inter Tropical Convergence Zone(ITCZ) and cyclone are important. In this study, the rainfall patterns are analyzed with synoptic analysis. The southern limit of ITCZ is around the arid zone around Namibia, Botswana, Zimbabwe and Mozambique. This zone has some effects of both ITCZ and extratropical cyclones by season. As well as this, the eastern part of this area has heavy rainfall by the cyclone from the Indian Ocean once in several years. In the other hand, a lot of wildfire occurs in this area. The main cause of the wildfire is anthropogenic misbehavior of the fire by the slash-and-burn agriculture. Recently we can find the wildfire detected with the satellite imagery like Terra/Aqua MODIS. We can compare the weather environment and the wildfire occurrence with Geographical Information System. We have tried making the fire weather index suitable for the southern African semi-arid area.

  2. Assessment of Microbial Process Potential for Natural Attenuation of Contaminants in the Thick Vadose Zone beneath the Wastewater-irrigated Area of Southern Shijiazhuang City, Hebei Province%河北省石家庄市南部污灌区厚层包气带污染物自然衰减的微生物作用潜力评价

    Institute of Scientific and Technical Information of China (English)

    张翠云; 张胜; 何泽; 殷密英; 宁卓

    2014-01-01

    本次研究的目的是利用传统的培养技术和现代的磷脂脂肪酸 PLFA(Phosphor Lipid Fatty Acid)技术、Biolog技术、16 S rRNA基因变性梯度凝胶电泳DGGE(Denaturing Gradient Gel Electrophoresis)及测序技术,调查石家庄市南部污灌区厚近30 m包气带微生物含量、分布、活性和多样性,评价污灌区厚层包气带污染物自然衰减的微生物作用潜力。包气带沉积物样品通过岩芯钻探获得,用于物理、化学和微生物分析。结果显示,土壤层(5~20 cm)微生物含量高,活性高,代谢类型多,可培养的异养菌与自养菌、好氧异养菌、兼性厌氧异氧菌和专性厌氧异养菌共存;土壤层下伏包气带微生物含量较低,活性降低,代谢类型减少,可培养的细菌主要是好氧性异养菌、兼性厌氧异养菌和好氧自养菌,而且随岩性而变化,在砂层和重粘土层含量低,活性低,而在亚粘土层含量和活性大。研究结果指示土壤层具有很高的污染物生物自然衰减潜力,而且下伏包气带仍有这种潜力,特别是下部溶解有机碳 DOC(Dissolved Organic Carbon)含量高的层位潜力更大。%The purpose of this study is to investigate the abundance, distribution, activity and diversity of microbes in nearly 30 m thick vadose zone beneath the wastewater-irrigated area of southern Shijiazhuang to assess microbial process potential for natural attenuation of contaminants of the thick vadose zone using traditional cultivation technique and modern phosphor lipid fatty acid (PLFA), Biolog and 16 S rRNA gene denaturing gradient gel electrophoresis (DGGE) techniques. Sediment samples were collected by core drilling for analysis of physical, chemical and microbial properties. The results show that the top soil layer (5~20 cm) is characterized by high content of bacteria, high activity, plenty of metabolizable types and coexistence of culturable heterotrophic bacteria and autotrophic

  3. The magnitude distribution of earthquakes near Southern California faults

    OpenAIRE

    Alderson, D; Doyle, J; Page, M.T.

    2011-01-01

    We investigate seismicity near faults in the Southern California Earthquake Center Community Fault Model. We search for anomalously large events that might be signs of a characteristic earthquake distribution. We find that seismicity near major fault zones in Southern California is well modeled by a Gutenberg-Richter distribution, with no evidence of characteristic earthquakes within the resolution limits of the modern instrumental catalog. However, the b value of the locally observed magnitu...

  4. Modeling the Migration of Soluble Methanol in Unsaturated Soil Zone

    Institute of Scientific and Technical Information of China (English)

    LI Hong; LI Xin-Gang; HUANG Guo-Qiang; JIANG Bin

    2007-01-01

    A combined model of solute transport and water flow was developed to simulate the migration of methanol, a soluble organic chemical, in unsaturated soil zone. The solute transport equation considered convective-dispersive transport in the liquid phase as well as diffusion in the gas phase. The effect of rainfall and evapotranspiration on transport was considered at the boundary conditions of the governing equations. Data on the characteristics of a loam soil and the climatic conditions in southern California were also introduced to compare the results with those from a study in the USA in which the profiles of methanol distribution and water content in the soil zone at different times had been depicted. This comparison showed that there was good agreement between the two studies. The results showed that methanol contamination reached a depth of about 250 cm after 8 760 h. In contrast, if rainfall and evapotranspiration were not considered, the depth was only about 140 cm. The model therefore confirmed that rainfall strongly affected solute transport.

  5. Metallurgical transformations of high strength low alloys steels 450 EMZ type II in the heat affected zone during multipass submerged arc welding; Proceso metalurgicos de aceros microaleados de alta resistencia 450 EMZ tipo II en la zona afectada termicamente debido al efecto mulipasada en soldaduras por arco sumergido

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Palma, R.; Suarez-Bermejo, J. C.; Vicario, F. J.; Munoz, A.

    2006-07-01

    A considerable number of crack tip opening displacement tests in the heat affected zone (HAZ) of multipass welds. performed in accordance with standards BS 5762 and EEMUA, are rejected since the crack is not inside the coarse grain region at 0.5 mm from the fusion border, as well as the quantity of the crack length in percentage, that the crack goes through the inter critical region instead of in the grain coarse region as it would correspond. This circumstance make advisable to carry out a metallographic study of he inter critical zone in the HAZ as well as the corresponding tests, in order analyze the inter critical region brittleness reasons. The study is performed on a HSLA 75 mm thick panel 450 EMZ type II, welded under a SAW process with heat input and welded parameters controlled, without any post weld heat treatment. (Author)

  6. Characteristics of climate change in the “significant impact zone” affected by aerosols over eastern China in warm seasons

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac- tive relationship with a variety of meteorological elements, it is found that the high-value zone of aerosol optical depth derived from the Total Ozone Mapping Spectrometer (TOMS), its significant negative correlation zones in terms of sunshine duration (SD) and surface air temperature (SAT) and its significant positive correlation zones with low-level cloud amount (LCC) are co-located in the South China region during warm periods. Based on this finding, the region is referred to as a "significant impact zone" (SI zone) affected by aerosols. Then, a comparative analysis is made on variation differ- ences of observed SAT, SD and LCC, etc. in different regions. It is also found that the LCC is increased and the SD is decreased within the "SI zone" over eastern China during the warm season. These characteristics are more evident than those beyond the zone, while the warming trend within the zone is evidently weaker than that outside it. Studies show that since recent 20 a, under the influence of aerosols, the LCC tend to increase substantially with a clear decrease of SD and an unnoticeable warming trend within the "SI zone". Comparing with the climate change beyond the zone, the difference is significant. Therefore, the effects of atmospheric aerosols on climate is possibly one of the contri- butions to the difference of climate change existed between the southern and northern parts of the Eastern China during a warm season.

  7. Prior history of Mistral and Tramontane winds modulates heavy precipitation events in southern France

    Directory of Open Access Journals (Sweden)

    Ségolène Berthou

    2014-11-01

    Full Text Available Heavy precipitation events (HPEs are frequent in southern France in autumn. An HPE results from landward transport of low-level moisture from the Western Mediterranean: large potential instability is then released by local convergence and/or orography. In the upstream zone, the sea surface temperature (SST undergoes significant variations at the submonthly time scale primarily driven by episodic highly energetic events of relatively cold outflows from the neighbouring mountain ranges (the Mistral and Tramontane winds. Here, we study the HPE of 22–23 September 1994 which is preceded by a strong SST cooling due to the Mistral and Tramontane winds. This case confirms that the location of the precipitation is modulated by the SST in the upstream zone. In fact, changes in latent and sensible heat fluxes due to SST changes induce pressure and stratification changes which affect the low-level dynamics. Using three companion regional climate simulations running from 1989 to 2009, this article statistically shows that anomalies in the HPEs significantly correlate with the SST anomalies in the Western Mediterranean, and hence with the prior history of Mistral and Tramontane winds. In such cases, the role of the ocean as an integrator of the effect of past wind events over one or several weeks does indeed have an impact on HPEs in southern France.

  8. No Moho uplift below the Baikal Rift Zone

    DEFF Research Database (Denmark)

    Nielsen, Christoffer; Thybo, Hans

    2009-01-01

    The late Cenozoic Baikal Rift Zone (BRZ) in southern Siberia is composed of several individual topographic depressions and half grabens with the deep Lake Baikal at its center. We have modeled the seismic velocity structure of the crust and uppermost mantle along a 360 km long profile of the Baikal...... Explosion Seismic Transects (BEST) project across the rift zone in the southern part of Lake Baikal. The seismic velocity structure along the profile is determined by tomographic inversion of first arrival times and 2-D ray tracing of first arrivals and reflections. The velocity model shows a gently...

  9. Holocene climate variability in the Winter Rainfall Zone of South Africa

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2013-05-01

    Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes and grain size of terrigenous fraction, and δ18O and δ13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in southern Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.

  10. A seamless, high-resolution, coastal digital elevation model (DEM) for Southern California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A seamless, three-meter digital elevation model (DEM) was constructed for the entire Southern California coastal zone, extending 473 km from Point Conception to the...

  11. 光修复热影响区深度对TC17-TC11双合金拉伸性能的影响%The Effect of Laser Repair Heat Affected Zone Depth on the Tensile Properties of TC17-TC11 Dual Alloy

    Institute of Scientific and Technical Information of China (English)

    张强; 陈静; 韩昌旭; 赵卫强; 林鑫

    2012-01-01

    以TC17合金锻件为基材,采用激光修复工艺方法,在其上沉积TC11合金粉末,制备TC17-TC11双合金修复试样,在双合金界面处靠近TC17锻件基体一侧观察到一定深度的热影响区.通过调整激光修复工艺参数(激光功率、扫描速度、送粉率),构造不同深度的热影响区,探讨热影响区深度对激光修复试样高温拉伸性能的影响.研究结果表明,高温拉伸时,修复试样表现为滑移分离型断裂,由于α/β两相的应变不协调,拉伸时裂纹萌生于TC11合金α/β相界面,其中热影响区深度为5 mm修复试样的强度和塑性匹配度好.随着热影响区深度的增加,修复试样的强度值呈现先升后降的趋势,热影响区深度为2 mm修复试样的抗拉强度最大,但其塑性较差.%Laser repair process was used to producted TC17-TC11 dual alloy samples, TC11 powders were deposited on the TC17 forging substrate. Certain depth of heat affect zone was observated at the interface close to the TC17 substrate side. Different depth of heat affected zone (HAZ) of TC17-TC11 dual alloys were constructed by adjusting the laser repaired process parameters, such as laser power, scanning rate, feed rate. Then discuss the impact of heat affected zone depth on laser repaired TC17-TC11 dual alloy high temperature tensile properties. The results indicated that, at high temperature, TC17-TC11 dual alloy formed sliding fracture, as a result of α/β phase strain is not harmonious, cracks formed in α/β interface, in which 5 mm HAZ sample has the best match of strength and ductility; As heat affected zone depth increasing, the strength of the samples showed first increased and then decreased, reaching the maximum value at 2 mm HAZ, but its ductility is very poor.

  12. Deciphering a multistage history affecting U-Cu(-Fe) mineralization in the Singhbhum Shear Zone, eastern India, using pyrite textures and compositions in the Turamdih U-Cu(-Fe) deposit

    Science.gov (United States)

    Pal, Dipak C.; Barton, Mark D.; Sarangi, A. K.

    2009-01-01

    The ˜200-km-long intensely deformed Singhbhum Shear Zone (SSZ) in eastern India hosts India’s largest U and Cu deposits and related Fe mineralization. The SSZ separates an Archaean cratonic nucleus to the south from a Mesoproterozoic fold belt in the North and has a complex geologic history that obscures the origin of the contained iron-oxide-rich mineral deposits. This study investigates aspects of the history of mineralization in the SSZ by utilizing new petrographic and electron microprobe observations of pyrite textures and zoning in the Turamdih U-Cu(-Fe) deposit. Mineralization at Turamdih is hosted in intensively deformed quartz-chlorite schist. Sulfides and oxides include, in inferred order of development: (a) magmatic Fe(-Ti-Cr) oxide and Fe-Cu(-Ni) sulfide minerals inferred to be magmatic (?) in origin; followed by (b) uranium, Fe-oxide, and Fe-Cu(-Co) sulfide minerals that predate most or all ductile deformation, and are inferred to be of hydrothermal origin; and (c) Fe-Cu sulfides that were generated during and postdating ductile deformation. These features are associated with the formation of three compositionally and texturally distinct pyrites. Pyrite (type-A), typically in globular-semiglobular composite inclusions of pyrite plus chalcopyrite in magnetite, is characterized by very high Ni content (up to 30,700 ppm) and low Co to Ni ratios (0.01-0.61). The textural and compositional characteristics of associated chalcopyrite and rare pyrrhotite suggest that this pyrite could be linked to the magmatic event via selective replacement of magmatic pyrrhotite. Alternatively, this pyrite and associated sulfide inclusions might be cogenetic with hydrothermal Fe-oxide. Type-B pyrite that forms elongate grains and irregular relics and cores of pyrite with high Co contents (up to 23,630 ppm) and high Co to Ni ratios (7.2-140.9) are interpreted to be related to hydrothermal mineralization predating ductile deformation. A third generation of pyrite (type C

  13. Seismicity of southern Lake Tanganyika

    Science.gov (United States)

    Lavayssiere, A.; Gallacher, R. J.; Keir, D.; Ebinger, C. J.; Drooff, C.; Khalfan, M.; Bull, J. M.

    2015-12-01

    Global seismic networks document frequent and unusually deep earthquakes in East African rift sectors lacking central volcanoes. The deep seismicity means that we can use earthquakes to probe the geometry and kinematics of fault systems throughout the crust, and to understand the distribution of strain between large offset border fault systems and intrabasinal faults. The southern Tanganyika rift zone has the highest seismicity rate within East Africa during the period 1973-present, yet earlier temporary seismometer networks have been too sparse in space and time to relocate earthquakes with location and depth errors of Lake Tanganyika since June 2014 using a network at 12 broadband seismic stations. The distribution of earthquakes shows that deformation primarily occurs on large offset border faults beneath the lake. Subsidiary earthquake activity occurs along the subparrallel Rukwa graben, and beneath the NE-SW striking Mweru rift. The distribution of earthquakes suggests the southern end of lake Tanganyika is characterized by a network of intersecting NNW and NE striking faults. The depths of earthquakes are distributed throughout the crust, consistent with the relatively strong lithosphere.

  14. Multiobjective optimization of GMAW process of the AA 6063-t5 alloy based on penetration and heat affected zone; Optimizacion multiobjetivo del proceso de soldeo GMAW de la aleacion AA 6063-T5 basado en la penetracion y en la zona afectada termicamente

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, V.; Marin-Ortiz, F.; Manjabacas, M. C.; Martinez-Conesa, E. J.; Martinez-Martinez, A.; Coello, J.

    2015-03-30

    The selection of technological parameters in a welding process must be led to the optimized results of the operation. Penetration is one of the most decisive factors for the success of the joint. Another important factor is the Heat Affected Zone (HAZ), when the mechanical properties of this one are modified respecting to the base material. The way in which the technological variables of the process affects to both them, penetration and HAZ, are inverse in each case. This work presents an optimization methodology based on the Design of Experiments (DOE) and the Response Surface Method (RSM) of the GMAW process applied to the aluminum alloy AA 6063-T5. This research is focused to obtain penetration rates that make HAZ values to be suitable in current applications. Welding rate has been found to be the most significant technological parameter for controlling the process. (Author)

  15. The impact of the Southern Annular Mode on future changes in Southern Hemisphere rainfall

    Science.gov (United States)

    Lim, Eun-Pa; Hendon, Harry H.; Arblaster, Julie M.; Delage, Francois; Nguyen, Hanh; Min, Seung-Ki; Wheeler, Matthew C.

    2016-07-01

    A robust positive trend in the Southern Annular Mode (SAM) is projected for the end of the 21st century under the Representative Concentration Pathway 8.5 scenario, which results in rainfall decreases in the midlatitudes and increases in the high latitudes in the Southern Hemisphere (SH). We find that this SAM trend also increases rainfall over the SH subtropics in austral summer but not in winter, leading to a pronounced wintertime poleward expansion of the subtropical dry zone. These dynamically driven rainfall changes by the SAM appear to oppose the thermodynamically driven projected rainfall changes in the SH subtropics and midlatitudes, whereas the two components reinforce each other in the high latitudes. However, we show that most climate models fall short in capturing the observed SAM component driven by the El Niño-Southern Oscillation and associated rainfall in the austral warm seasons, which limits our confidence in quantifying the contribution of the SAM to projected rainfall changes.

  16. Southern Identity in "Southern Living" Magazine

    Science.gov (United States)

    Lauder, Tracy

    2012-01-01

    A fantasy-theme analysis of the editors' letters in "Southern Living" magazine shows an editorial vision of valuing the past and showcasing unique regional qualities. In addition, a content analysis of the visual representation of race in the magazine's formative years and recent past validates that inhabitants of the region were portrayed…

  17. The Lake Gordan mylonite zone: A link between the Nutbush Creek and Hylas zones of Eastern Piedmont fault system

    Energy Technology Data Exchange (ETDEWEB)

    Horton, J.W. Jr.; Sacks, P.E. (Geological Survey, Reston, VA (United States)); Berquist, C.R. Jr.; Marr, J.D. Jr. (Virginia Div. of Mineral Resources, Charlottesville, VA (United States)); Druhan, R.M. (Robert M. Carolina Friends School, Durham, NC (United States)); Butler, J.R. (Univ. of North Carolina, Chapel Hill, NC (United States). Geology Dept.)

    1993-03-01

    Preliminary results of geologic mapping indicate that the Nutbush Creek and Hylas mylonite zone of the lake Paleozoic Eastern Piedmont fault system are not coextensive, as has been proposed. In south-central Virginia and northern North Carolina, a separate NNE-trending, orogen-parallel mylonite zone, the Lake Gordon mylonite zone, lies between the Nutbush Creek and Hylas zone and may link them. The Lake Gordon mylonite zone, named for exposures near Lake Gordon Mecklenburg Co., Va., lies mainly along the eastern flank of the Buggs Island granite pluton and has been mapped for a distance of about 80 km. Reconnaissance between Blackstone and Kenbridge, Va., suggests that the Lake Gordon mylonite zone is linked to the Hylas zone by either a releasing bend or an en echelon right step. The Lake Gordon and Nutbush Creek mylonite zone converge southward and are separated by only 3 km of granitic gneiss at the southern limit of mapping near Henderson, N.C. Mylonitic foliation in the Lake Gordon mylonite zone strikes 10--25[degree] E., dips subvertically to steeply northwest, and is parallel to the mapped boundaries of the zone. Intensity of mylonitization varies across the 1.5--3.6-km width of the zone. Subhorizontal mineral-elongation lineation is common in the plane of mylonitic foliation. Asymmetric porphyroclasts and shear bands indicate dextral simple shear. Coincidence of the Lake Gordon and Nutbush Creek mylonite zones, respectively, with the eastern and western margins of the highly elongate Buggs Island granite pluton suggests that the mylonite zones influenced emplacement of the pluton. These map relations, combined with very localized mylonitic fabric in the granite, suggest that mylonite in the Lake Gordon zone, like that in the Nutbush Creek zones is partly coeval with the Pennsylvanian-age Buggs Island granite. Postmylonitic brittle faulting is found locally in both the Lake Gordon and the Nutbush Creek zones.

  18. Root Apex Transition Zone as Oscillatory Zone

    Directory of Open Access Journals (Sweden)

    Frantisek eBaluska

    2013-10-01

    Full Text Available Root apex of higher plants shows very high sensitivity to environmental stimuli. The root cap acts as the most prominent plant sensory organ; sensing diverse physical parameters such as gravity, light, humidity, oxygen and critical inorganic nutrients. However, the motoric responses to these stimuli are accomplished in the elongation region. This spatial discrepancy was solved when we have discovered and characterized the transition zone which is interpolated between the apical meristem and the subapical elongation zone. Cells of this zone are very active in the cytoskeletal rearrangements, endocytosis and endocytic vesicle recycling, as well as in electric activities. Here we discuss the oscillatory nature of the transition zone which, together with several other features of this zone, suggest that it acts as some kind of command centre. In accordance with the early proposal of Charles and Francis Darwins, cells of this root zone receive sensory information from the root cap and instruct the motoric responses of cells in the elongation zone.

  19. Peak metamorphic temperature and thermal history of the Southern Alps (New Zealand)

    Science.gov (United States)

    Beyssac, O.; Cox, S. C.; Vry, J.; Herman, F.

    2016-04-01

    The Southern Alps orogen of New Zealand results from late Cenozoic convergence between the Indo-Australian and Pacific plates and is one of the most active mountain belts in the world. Metamorphic rocks carrying a polymetamorphic legacy, ranging from low-greenschist to high-grade amphibolites, are exhumed in the hanging wall of the Alpine Fault. On a regional scale, the metamorphic grade has previously been described in terms of metamorphic zones and mineral isograds; application of quantitative petrology being severely limited owing to unfavorable quartzofeldspathic lithologies. This study quantifies peak metamorphic temperatures (T) in a 300 × 20 km area, based on samples forming 13 transects along-strike from Haast in the south to Hokitika in the north, using thermometry based on Raman spectroscopy of carbonaceous material (RSCM). Peak metamorphic T decreases across each transect from ≥ 640 °C locally in the direct vicinity of the Alpine Fault to less than 330 °C at the drainage divide 15-20 km southeast of the fault. Thermal field gradients exhibit a degree of similarity from the southernmost to the northernmost transects, are greater in low-grade semischist than high-grade schist, are affected by folding or discontinuous juxtaposition of metamorphic zones, and contain limited information on crustal-scale geothermal gradients. Temperatures derived by RSCM thermometry are slightly (≤ 50 °C) higher than those derived by traditional quantitative petrology using garnet-biotite thermometry and THERMOCALC modeling. The age of RSCM T appears to be mostly pre-Cenozoic over most of the area except in central Southern Alps (Franz Josef-Fox area), where the amphibolite facies schists have T of likely Cenozoic age. The RSCM T data place some constraints on the mode of exhumation along the Alpine Fault and have implications for models of Southern Alps tectonics.

  20. Conservation of the Red Kite Milvus milvus (Aves: Accipitriformes) Is Not Affected by the Establishment of a Broad Hybrid Zone with the Black Kite Milvus migrans migrans in Central Europe

    Science.gov (United States)

    Matušík, Hynek; Pfeiffer, Thomas; Nachtigall, Winfried; Bizos, Jiří; Šimčíková, Daniela; Literák, Ivan

    2016-01-01

    Among Accipitriformes sensu stricto, only a few species have been reported to form hybrid zones; these include the red kite Milvus milvus and black kite Milvus migrans migrans. M. milvus is endemic to the western Palearctic and has an estimated total population of 20–24,000 breeding pairs. The species was in decline until the 1970s due to persecution and has declined again since the 1990s due to ingestion of rodenticide-treated baits, illegal poisoning and changes in agricultural practices, particularly in its core range. Whereas F1 M. milvus × M. migr. migrans hybrid offspring have been found, F2 and F3 hybrids have only rarely been reported, with low nesting success rates of F1 hybrids and partial hybrid sterility likely playing a role. Here, we analyzed the mitochondrial (CO1 and CytB) and nuclear (Myc) DNA loci of 184 M. milvus, 124 M. migr. migrans and 3 F1 hybrid individuals collected across central Europe. In agreement with previous studies, we found low heterozygosity in M. milvus regardless of locus. We found that populations of both examined species were characterized by a high gene flow within populations, with all of the major haplotypes distributed across the entire examined area. Few haplotypes displayed statistically significant aggregation in one region over another. We did not find mitochondrial DNA of one species in individuals with the plumage of the other species, except in F1 hybrids, which agrees with Haldane´s Rule. It remains to be investigated by genomic methods whether occasional gene flow occurs through the paternal line, as the examined Myc gene displayed only marginal divergence between M. milvus and M. migr. migrans. The central European population of M. milvus is clearly subject to free intraspecific gene flow, which has direct implications when considering the origin of individuals in M. milvus re-introduction programs. PMID:27463515

  1. Constriction structures related to viscous collision, southern Prince Charles Mountains, Antarctica

    Science.gov (United States)

    Corvino, Adrian F.; Boger, Steven D.; Fay, Clement

    2016-09-01

    Macroscopic structures are investigated in a zone of highly contorted migmatites from the southern Prince Charles Mountains, Antarctica. Here, L-tectonite fabrics, rods, mullions, boudin pods, elongate enclaves, and fold hinges, are persistent linear features all plunging gently to the northeast. In contrast, amoeboid folds, ptygmatic folds and folded boudins with different orientations are the characteristic structures in transverse sections (perpendicular to the lineation). No consistent shear sense is recognised in any dimension. Together with strain and shape analysis, these observations strongly suggest that the deformation pattern is one of folding and stretching by constriction. Previous timing constraints indicate that this deformation overlapped with the waning stages of anatexis during decompression at approximately 510 Ma, up to 30 million years after initial orogeny at 540 Ma. The zone affected by constriction is several kilometres wide and has a contorted flower-like shape confined between two broad domal antiforms. In this context, the constricted zone is interpreted as a relatively late tectonic feature that could have formed via deep-seated viscous collision in response to orogenic collapse and doming.

  2. Hydrogeological impact of fault zones on a fractured carbonate aquifer, Semmering (Austria)

    Science.gov (United States)

    Mayaud, Cyril; Winkler, Gerfried; Reichl, Peter

    2015-04-01

    Fault zones are the result of tectonic processes and are geometrical features frequently encountered in carbonate aquifer systems. They can hamper the fluid migration (hydrogeological barriers), propagate the movement of fluid (draining conduits) or be a combination of both processes. Numerical modelling of fractured carbonate aquifer systems is strongly bound on the knowledge of a profound conceptual model including geological and tectonic settings such as fault zones. In further consequence, numerical models can be used to evaluate the conceptual model and its introduced approximations. The study was conducted in a fractured carbonate aquifer built up by permomesozoic dolo/limestones of the Semmering-Wechsel complex in the Eastern Alps (Austria). The aquifer has an assumed thickness of about 200 m and dips to the north. It is covered by a thin quartzite layer and a very low permeable layer of quartz-phyllite having a thickness of up to several hundred meters. The carbonate layer crops out only in the southern part of the investigation area, where it receives autogenic recharge. The geological complexity affects some uncertainties related to the extent of the model area, which was determined to be about 15 km². Three vertical fault zones cross the area approximately in a N-S direction. The test site includes an infrastructural pilot tunnel gallery of 4.3 km length with two pumping stations, respectively active since August 1997 and June 1998. The total pumping rate is about 90 l/s and the drawdown data were analysed analytically, providing a hydraulic conductivity of about 5E-05 m/s for the carbonate layer. About 120 m drawdown between the initial situation and situation with pumping is reported by piezometers. This led to the drying up of one spring located at the southern border of the carbonates. A continuum approach using MODFLOW-2005 was applied to reproduce numerically the observed aquifer behaviour and investigate the impact of the three fault zones. First

  3. Along strike variation of tremor activities and thermal structures in various subduction zones

    Science.gov (United States)

    Yabe, S.; Ide, S.; Yoshioka, S.

    2012-12-01

    A family of slow earthquakes, e.g., deep low frequency tremors, low frequency earthquakes (LFEs), very low frequency earthquakes (VLFs) and slow slip events (SSEs), are observed in various subduction zones. These phenomena represent shear slip on the plate interface, and they are thought to be related to brittle-ductile transition behavior on the plate interface because they are often located near the transition zones of interplate coupling estimated from GPS data. Such slip behavior along the plate interface would be controlled by temperature. Furthermore, tremors are considered to be related to fluid dehydrated from the subducting slab, through temperature dependent chemical reactions. Therefore, tremors occurrences are expected to be influenced by temperature, though some studies have questioned about the relationship between tremor activity and temperature. Here we investigate the source locations of deep tremor using an envelope correlation method and compare them with the temperature and shear strength profiles along the plate interface calculated using a numerical model (Yoshioka and Sanshadokoro, 2002). The study areas include New Zealand, southern Chile, and Mexico, where tremor behavior changes significantly along the strike of the plate interface. Investigating such along-strike variation in individual subduction zone may clarify the temperature dependence of tremor because environmental conditions affecting tremor occurrence are similar, unlike the comparison between different subduction zones. In the Hikurangi subduction zone beneath the North Island, New Zealand, the depth of SSE are quite different along the strike, e.g., deeper in the central region and shallower in the northern region (e.g. Wallace and Beavan, 2010). We reanalyze tremors detected by previous studies (Kim et al., 2011; Ide, 2012) to estimate their absolute depth and confirm that tremors in North Island are on the plate interface in both the central and the northern regions. Thermal

  4. ShenZhen,The First Special Economic Zone

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Shenzhen is a city of sub-provincial administrative status in southern China's Guangdong province,situated immediately north of Hong Kong.Owing to China's reform and opening policy made by reformist leader Deng Xiaoping.the area became China's first--and ultimately most successful--Special Economic Zone.

  5. The differences in clay minerals between the northern and southern Chelungpu fault, Taiwan

    Science.gov (United States)

    Hashimoto, Y.

    2004-12-01

    In 1999, we obtained a detailed data about motion of fault from the Taiwan Chi-Chi earthquake. The motion represents the high frequency of acceleration and small slip distance in southern part, and low frequency of acceleration and large slip distance in the northern part. Those differences in the fault motion between the southern and northern parts are coincidence with occurrences of deformation textures of rocks which were sampled by drilling of shallow parts (a few hundreds meter) of the fault in 2000. In the southern core, a relatively strong deformation structure is preserved in total, and gouge containing fragments of pseudotachylytes and ultracataclasites is observed at the Chi-Chi- earthquake fault, which indicates that the main deformation mechanisms for the southern part of the fault was brittle. On the other hands, in the northern part, sand layer with much amount of water is found at the Chi-Chi- earthquake fault zone, and no breakage of sand grain is observed, which suggests that the deformation mechanism for northern part is independent particulate flow. The purpose of this study is to reveal the differences in clay minerals between the southern and northern part of the Chi-Chi earthquake fault. And then, we discuss about rock-fluid interaction and frictional heating characterized in seismogenic fault system. We analyzed clay minerals by X-ray diffract meter (XRD) after classification of rock types such as sandstone, alteration of sandstone and mudstone, breccia, and gouge. 1.33 micron meter of grains are obtained. Oriented sample was made. XRD analysis was conducted under following condition; 35kV, 15mA, 1 degree per minute of scan rate, and 0.02 degree of scan step. Range of 2 theta was from 2 degree to 35 degree. At first, air-dried condition of samples was measured. After that, ethylene glycol solvated samples were measured. The result represents that all samples contain smectite, illite, chlorite. No difference in components of clay mineral is

  6. Disease burden after ice and snow disaster in one heavily affected county-southern China, 2008%南方低温雨雪冰冻灾害的疾病负担研究

    Institute of Scientific and Technical Information of China (English)

    张必科; 段良松; 曾光; 李群; 高立冬; 阮峰; 张廷禄; 施国庆; 马会来; 贺平; 付敏; 钟西园

    2012-01-01

    目的 评估低温雨雪冰冻灾害可能造成的健康损失,为采取针对性的预防和减轻措施提供依据.方法 收集了我国南方某省CZ市SX区1月13日到2月8日灾害期间主要医疗机构的临床记录,筛查其中死亡、骨折、一氧化碳中毒和心脏病急性发作等病例,并以人口普查资料作为计算本次发生率的分母,对灾害期数据与前两年同期数据进行了比较.结果 与2006-2007年同期相比,灾害期间被调查地区的超额死亡率为0.98/10000,其中循环系统和CO中毒的超额死亡率分别为0.49/10000和0.35/10000;与2004-2007年同期相比,灾害期间被调查地区主要与灾害有关的传染病超额发病率为-3.75/100000;与2007年同期相比,灾害期间被调查地区急救转运病例发生率增加了0.98‰,医疗机构门诊就诊率下降了2.1‰,而急诊科门诊就诊率增加了0.08‰;医疗机构病人住院率下降了0.11‰,而CO中毒和骨折病人住院率分别增加了0.41‰和0.16‰.结论 低温雨雪冰冻灾害增加了CO中毒、骨折和循环系统等特殊疾病的死亡率或发病率.有必要采取措施,预防和缓解和寒冷有关的疾病,特别是一氧化碳中毒的发生.%Objective To estimate the disease burden after ice and snow disasters in SX County in Southern China s one province and to provide the evidence on reducing disease burden during ice and snow disaster. Methods The disaster period was defined as January 13 to February 8, 2008. We reviewed hospitalization records in all township and county level hospitals in SX County to identify all deaths, bone fractures, carbon monoxide (CO) poisonings and heart attacks. We compared the data between the disaster period and the same time period during the previous years. Census data were used as the denominator for calculating rates. Results Compared to the average mortality rate of the same period during 2006 and 2007, the total excess mortality rate and circulatory system

  7. Carbon dioxide efflux in a rhodic hapludox as affected by tillage systems in southern Brazil Emissão de dióxido de carbono em latossolo vermelho alterada por sistemas de preparo no sul do Brasil

    Directory of Open Access Journals (Sweden)

    Luis Fernando Chavez

    2009-04-01

    Full Text Available Agricultural soils can act as a source or sink of atmospheric C, according to the soil management. This long-term experiment (22 years was evaluated during 30 days in autumn, to quantify the effect of tillage systems (conventional tillage-CT and no-till-NT on the soil CO2-C flux in a Rhodic Hapludox in Rio Grande do Sul State, Southern Brazil. A closed-dynamic system (Flux Chamber 6400-09, Licor and a static system (alkali absorption were used to measure soil CO2-C flux immediately after soybean harvest. Soil temperature and soil moisture were measured simultaneously with CO2-C flux, by Licor-6400 soil temperature probe and manual TDR, respectively. During the entire month, a CO2-C emission of less than 30 % of the C input through soybean crop residues was estimated. In the mean of a 30 day period, the CO2-C flux in NT soil was similar to CT, independent of the chamber type used for measurements. Differences in tillage systems with dynamic chamber were verified only in short term (daily evaluation, where NT had higher CO2-C flux than CT at the beginning of the evaluation period and lower flux at the end. The dynamic chamber was more efficient than the static chamber in capturing variations in CO2-C flux as a function of abiotic factors. In this chamber, the soil temperature and the water-filled pore space (WFPS, in the NT soil, explained 83 and 62 % of CO2-C flux, respectively. The Q10 factor, which evaluates CO2-C flux dependence on soil temperature, was estimated as 3.93, suggesting a high sensitivity of the biological activity to changes in soil temperature during fall season. The CO2-C flux measured in a closed dynamic chamber was correlated with the static alkali adsorption chamber only in the NT system, although the values were underestimated in comparison to the other, particularly in the case of high flux values. At low soil temperature and WFPS conditions, soil tillage caused a limited increase in soil CO2-C flux.Os solos agr

  8. X70焊管焊接接头热影响区冲击试样缺口位置的探讨%Discussion on Impact Specimen Notch Position of X70 Welded Pipe Heat Affected Zone(HAZ)

    Institute of Scientific and Technical Information of China (English)

    王丽丽; 刘通; 王自信; 顾志乾

    2015-01-01

    In this article, it studied the distribution situation of metallographic structure, impact energy and shearing area of X70 SAWH pipe welded joint HAZ specimen in different Notch position, by adopting metallographic test and Charpy impact test. The results indicated that the values of impact energy value and shearing area are related with Notch position proportion in coarse grained region, fine grained region, part of the phase change zone and inside weld. The lower the proportion of inside weld is, the greater the impact energy and shearing area. After comprehensive analysis of test results and related standards, the determination method of X70 SAWH pipe welded joint HAZ specimen Notch position was obtained; the Notch axis of HAZ impact specimen should be in the junction of specimen upper surface and outside weld fusion line, and the distance from Impact test specimen edges to the outside weld edge of 1~2 mm is applicable.%通过金相试验、夏比冲击试验研究了X70螺旋埋弧焊管焊接接头热影响区试样不同缺口位置的金相组织、冲击功及剪切面积的分布情况。试验结果显示,冲击功和剪切面积的大小与缺口位置在粗晶区、细晶区、部分相变区和内焊缝所占的比例相关,内焊缝所占比例越低,冲击功和剪切面积越大。综合分析试验结果和相关标准,得出了X70焊管焊接接头热影响区试样缺口位置的确定方法,即热影响区冲击试样的缺口轴线应在试样上表面与外焊缝熔合线交界处,冲击试样边缘距外焊缝边缘1~2 mm为宜。

  9. Structural analysis and magmatism characterization of the Major Gercino shear zone, Santa Catarina State, Brazil; Analise estrutural e caracterizacao do magmatismo da zona de cisalhamento Major Gercino, SC

    Energy Technology Data Exchange (ETDEWEB)

    Passarelli, Claudia Regina

    1996-12-31

    This work describes the geometric and kinematic characteristics of the Major Gercino Shear Zone (MGSZ) in the Canelinha-Garcia area. This shear zone is one of the major lineaments that affect all southern Brazilian precambrian terrains. In Santa Catarina State, it separates, along its whole extension, the supracrustal rocks of the Brusque belt (northern part) from the Granitoid belt (southern). This zone is characterized by a regional NE trend and a dextral sense of movement where ductile-brittle structures predominate. The MGSZ is composed of two mylonitic belts separated by granitoid rocks probably associated to the development of the shear zone. Both shear zones show cataclastic to ultra mylonitic rocks, but mylonites and protomylonites conditions at high strain rate. The calc-alkaline granitoids present in the area can be grouped in two granitoid associations with meta to peraluminous affinities. The Rolador Granitoid Association is characterized by grayish porphyritic biotite-monzogranites and the Fernandes Granitoid Association by coarsed-grained to porphyritic pinkish amphibole-syenogranites. The U-Pb and Rb-Sr ages range from 670 to 590 Ma with the Sr{sup 87} / Sr{sup 86} initial ratios suggesting a crustal contribution in the generation of these rocks. The importance of the pure shear component is also emphasized by the results of the Fry method. Many z axes of the strain ellipses are at high angle to the shear foliation. Symmetric porphyroclasts also corroborate this hypothesis. The micaceous minerals formed during the shear development indicate K-Ar ages around 555 {+-} 15 Ma. Brittle reactivations of the shear zone have been placed by K-Ar in fine-fraction materials at Triassic time (215 {+-} 15 Ma.) 220 refs., 107 figs., 18 tabs., 4 maps

  10. Earthquakes in Southern California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — There have been many earthquake occurrences in Southern California. This set of slides shows earthquake damage from the following events: Imperial Valley, 1979,...

  11. European Southern Observatory

    CERN Multimedia

    1970-01-01

    Professor A. Blaauw, Director general of the European Southern Observatory, with George Hampton on his right, signs the Agreement covering collaboration with CERN in the construction of the large telescope to be installed at the ESO Observatory in Chile.

  12. 发展潜力视角的海岸带土地利用模式——以杭州湾南岸为例%Land-use pattern in coastal zone from the perspective of development potentiality: A case study of the southern bank of Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    李伟芳; 陈阳; 马仁锋; 俞腾; 任丽燕; 李加林

    2016-01-01

    ) and GIS spatial analysis.The paper analyzed the factors in land-use pattem for coastal zone,explained the relationship among land use optimization,spatial restructuring and spatial management strategies,and presented an economic-ecological synergic pattern for the coastal zone on the southem bank of Hangzhou Bay.We found that scientific evaluation of the relationship between economy and ecology is critical for measuring coastal land efficiency development potentiality evaluation on the basis of inversely proportional relation is useful to find out the conflict between economy and ecology,and provide methodological support for preventing expansion to ecological sensitive areas.In areas south of the Hangzhou Bay,57.07% of the coastal land is of high or extreme high potentiality,and the rest is of moderate or low potentiality,showing its generally high potentiality,and a pattern of "high in the South and lower in the North".With the decrease of human land use,and increase of the natural land,the potentiality of land use decreases.An economy-ecology synergy model for coastal land-use model is proposed for the southern bank of Hangzhou Bay,to meet the demand of the economic-oriented practice.The three main principals of the model include (1) land-use optimization for "stable economic development,strict ecological conservation and good coordination for both economy and ecology";(2) spatial restructuring for "systemic coordination of land and ocean,and cluster of multi-function lands";(3) the spatial governance for synergy of the three kinds of areas of "residence,production and ecology".

  13. Structural geology of the French Peak accommodation zone, Nevada Test Site, southwestern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, M.R.

    1997-12-31

    The French Peak accommodation zone (FPAZ) forms an east-trending bedrock structural high in the Nevada Test Site region of southwestern Nevada that formed during Cenozoic Basin and Range extension. The zone separates areas of opposing directions of tilt and downthrow on faults in the Yucca Flat and Frenchman Flat areas. Paleomagnetic data show that rocks within the accommodation zone adjacent to Yucca Flat were not strongly affected by vertical-axis rotation and thus that the transverse strikes of fault and strata formed near their present orientation. Both normal- and oblique strike-slip faulting in the FPAZ largely occurred under a normal-fault stress regime, with least principal stress oriented west-northwest. The normal and sinistral faults in the Puddle Peka segment transfers extension between the Plutonium Valley normal fault zone and the Cane Spring sinistral fault. Recognition of sinistral shear across the Puddle Peak segment allows the Frenchman Flat basin to be interpreted as an asymmetric pull-apart basin developed between the FPAZ and a zone of east-northeast-striking faults to the south that include the Rock Valley fault. The FPAZ has the potential to influence ground-water flow in the region in several ways. Fracture density and thus probably fracture conductivity is high within the FPAZ due to the abundant fault splays present. Moreover,, fractures oriented transversely to the general southward flow of ground water through Yucca Flat area are significant and have potential to laterally divert ground water. Finally, the FPAZ forms a faulted structural high whose northern and southern flanks may permit intermixing of ground waters from different aquifer levels, namely the lower carbonate, welded tuff, and alluvial aquifers. 42 refs.

  14. Southern hemisphere observations

    Science.gov (United States)

    Orchiston, Wayne

    Because of insurmountable problems associated with absolute dating, the non-literate cultures of the Southern Hemisphere can contribute little to Applied Historical Astronomy, although Maori traditions document a possible supernova dating to the period 1000-1770 AD. In contrast, the abundant nineteenth century solar, planetary, cometary and stellar observational data provided by Southern Hemisphere professional and amateur observatories can serve as an invaluable mine of information for present-day astronomers seeking to incorporate historical data in their investigations.

  15. Geochemistry and paleotectonic setting of Ediacaran metabasites from the Ossa-Morena Zone (SW Iberia)

    Science.gov (United States)

    Sánchez Lorda, M. E.; Sarrionandia, F.; Ábalos, B.; Carrracedo, M.; Eguíluz, L.; Gil Ibarguchi, J. I.

    2014-07-01

    New results on the geochemistry of Neoproterozoic (late Ediacaran) metabasites of the Ossa-Morena Zone (OMZ, Iberian Massif) are presented. The metabasite suite exhibits N- and E-MORB signatures, as well as volcanic arc signatures. The three amphibolite groups are discerned on the basis of major and trace element contents, and the Nd isotope relations help unravel the existence of a diverse magmatism during late Ediacaran times across the OMZ. N-MORB "Serie Negra" metabasites are distributed in the southern and, mostly, the central OMZ (Monesterio antiform). Calc-alkaline metabasites are exclusively constrained to the Coimbra-Córdoba sector of the northern OMZ. Finally, E-MORB-type metabasites are widespread across the entire OMZ. In present-day active geodynamic settings, such magma types are typical of younger island arcs, notably of forearc zones that are affected by extension soon after the initiation of subduction. The new geochemical data permit us to postulate a petrological zonation congruent with a N-dipping subduction zone located to the S of the current OMZ during the late Ediacaran. We argue that the metabasite host units represent (continental) shallow-crustal forearc segments of a convergent margin. The volcanic arc edifice would have developed during the latest Ediacaran to early Cambrian times and has been preserved, often without major orogenic reworking, in the central and northern OMZ.

  16. Geophysical investigation of seamounts near the Ogasawara Fracture Zone, western Pacific

    Science.gov (United States)

    Lee, T.-G.; Lee, K.; Hein, J. R.; Moon, J.-W.

    2009-03-01

    This paper provides an analysis of multi-channel seismic data obtained during 2000-2001 on seamounts near the Ogasawara Fracture Zone (OFZ) northwest of the Marshall Islands in the western Pacific. The OFZ is unique in that it is a wide rift zone that includes many seamounts. Seven units are delineated on the basis of acoustic characteristics and depth: three units (I, II, and III) on the summit of seamounts and four units (IV, V, VI, and VII) in basins. Acoustic characteristics of layers on the summit of guyots and dredged samples indicate that the seamounts had been built above sea level by volcanism. This was followed by reef growth along the summit margin, which enabled deposition of shallow-water carbonates on the summit, and finally by subsidence of the edifices. The subsidence depth of the seamounts, estimated from the lower boundary of unit II, ranges between 1,550 and 2,040 m. The thick unit I of the southern seamounts is correlated with proximity to the equatorial high productivity zone, whereas local currents may have strongly affected the distribution of unit I on northern seamounts. A seismic profile in the basin around the Ita Mai Tai and OSM4 seamounts shows an unconformity between units IV and V, which is widespread from the East Mariana Basin to the Pigafetta Basin.

  17. Indirect taxes on food in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Denize Mirian da Silva

    2013-12-01

    Full Text Available The objective of this paper is to estimate the indirect tax burden on food for ten income classes, based on income and household total expenditure in southern Brazil. Thus it can be seen as indirect taxes on foods affect the monetary income and consumption pattern of households. To reach the objectives proposed, will be used the Pintos-Payeras (2008 model. The database iscomposed by microdata from the Household Budgeting Survey (POF 2008-2009 and the tax regulations of the country and the southern states of Brazil. The results show that indirect taxes on food in Southern Brazil is regressive when based on income and expenditure of household , ie , the poorest people pay proportionately more taxes and have their consumption pattern highest taxed ICMS (Brazilian value added tax is the tax that contributes most to the regressivity.

  18. Thermal ground water flow systems in the thrust zone in southeastern Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Ralston, D.R.

    1983-05-01

    The results of a regional study of thermal and non-thermal ground water flow systems in the thrust zone of southern Idaho and western Wyoming are presented. The study involved hydrogeologic and hydrochemical data collection and interpretation. Particular emphasis was placed on analyzing the role that thrust zones play in controlling the movement of thermal and non-thermal fluids.

  19. Nasal rhinosporiodiosis from uttar pradesh (India: a non-endemic zone: first case report

    Directory of Open Access Journals (Sweden)

    Shalini Malhotra

    2011-06-01

    Full Text Available Rhinosporiodiosis is a cosmopolitan disease of man and animals, endemic in India and Sri Lanka with main focus of infection in Southern Tamil Nadu. Uttar Pradesh (UP is not known to be an endemic zone for this disease .We present here the first case of nasal Rhinosporiodiosis from this non-endemic zone.

  20. The Herpetology of the Southern Kalahari domain

    Directory of Open Access Journals (Sweden)

    W. D Haacke

    1984-12-01

    Full Text Available The herpetofauna of the southern Kalahari has mixed affinities, as this area lies on a rainfall gradient in a critical area where a transition between the arid south-west and the moister north-east takes place. As the variation in substrate type is relatively limited, the effect of the rainfall gradient appears to influence and determine the range limits of many taxa in both directions, resulting in an area in which of 55 recorded reptiles, 11 western taxa overlap or form a parapatric zone with 25 eastern taxa, while the remaining taxa are endemic or wideranging.

  1. The Herpetology of the Southern Kalahari domain

    OpenAIRE

    W. D Haacke

    1984-01-01

    The herpetofauna of the southern Kalahari has mixed affinities, as this area lies on a rainfall gradient in a critical area where a transition between the arid south-west and the moister north-east takes place. As the variation in substrate type is relatively limited, the effect of the rainfall gradient appears to influence and determine the range limits of many taxa in both directions, resulting in an area in which of 55 recorded reptiles, 11 western taxa overlap or form a parapatric zone wi...

  2. Plant diversity in different bioclimatic zones in Tunisia

    Directory of Open Access Journals (Sweden)

    Hana You

    2016-03-01

    Full Text Available The Republic of Tunisia, located in northern Africa, faces various environmental challenges caused by anthropogenic practices such as overgrazing, deforestation, and desertification. The conversion of natural ecosystems is the major cause of plant biodiversity loss. Tunisia can be divided into three main climatic zones as follows: a northern Mediterranean climate zone, a central steppe climate zone, and a southern desert climate zone. Because of this great environmental diversity, there are distinctive vegetation and various genetic resources in Tunisia. This research was conducted to investigate plant biodiversity within the various bioclimatic zones and to characterize useful plant resources in Tunisia. We investigated native, medicinal and aromatic, desert, and soil erosion control plant species.

  3. Climatic Zones, Soil Moisture Seasonality and Biomass Burning and Their Influence On Ozone Precursor Concentrations Over West Africa as Retrieved from Satellites

    Science.gov (United States)

    Onojeghuo, A. R.; Balzter, H.; Monks, P. S.

    2015-12-01

    West Africa is a region with six different climatic zones including a rich savannah affected by biomass burning annually, the Niger delta oil producing region with major gas flaring sites and a long coastline. Research on atmospheric pollution using remotely sensed data over West Africa has mostly been conducted at regional scale or for individual countries, with little emphasis on the dynamics of climatic zones and the diversity of land cover types. This study analyses annual seasonal dynamics of emissions of two ozone precursors stratified by climatic zone: nitrogen dioxide (NO2) from OMI and carbon monoxide (CO) from TES. The different sources of these pollutants and their seasonality are explicitly considered. Results indicate that the highest annual wet season NO2 column concentrations were in the semi-arid zone (1.33 x 1015 molecules cm-2) after prolonged periods of low soil moisture while the highest dry season were observed in the wet sub-humid zone (2.62 x 1015 molecules cm-2) where the savannah fires occur annually. The highest annual CO concentrations (> 3.1 x 1018 molecules cm-2) were from the Niger Delta, located in the humid zone. There were indications of atmospheric transport of CO from the southern hemisphere in the west season. Climate change induced soil moisture variability was most prominent in the dry sub-humid and semi-arid climatic zones (±0.015m3m-3) . The causal effects of soil moisture variability on NO2 emissions and their seasonal cycles were tested using the Granger causality test. Causal effects of inter-zonal exchanges/transport of NO2 and CO emissions respectively were inferred using Directed Acyclic Graphs. The results indicate that NO2, CO and their seasonal ratios are strongly affected by changes in soil moisture.

  4. Groundwater Flow and Radionuclide Transport in Fault Zones in Granitic Rock

    International Nuclear Information System (INIS)

    Fault zones are potential paths for release of radioactive nuclides from radioactive-waste repositories in granitic rock. This research considers detailed maps of en echelon fault zones at two sites in southern Sweden, as a basis for analyses of how their internal geometry can influence groundwater flow and transport of radioactive nuclides. Fracture intensity within these zones is anisotropic and correlated over scales of several meters along strike, corresponding to the length and spacing of the en echelon steps. Flow modeling indicates these properties lead to correlation of zone transmissivity over similar scales. Intensity of fractures in the damage zone adjoining en echelon segments decreases exponentially with distance. These fractures are linked to en echelon segments as a hierarchical pattern of branches. Echelon steps also show a hierarchical internal structure. These traits suggest a fractal increase in the amount of pore volume that solute can access by diffusive mass transfer, with increasing distance from en echelon segments. Consequences may include tailing of solute breakthrough curves, similar to that observed in underground tracer experiments at one of the mapping sites. The implications of echelon-zone architecture are evaluated by numerical simulation of flow and solute transport in 2-D network models, including deterministic models based directly on mapping data, and a statistical model. The simulations account for advection, diffusion-controlled mixing across streamlines within fractures and at intersections, and diffusion into both stagnant branch fractures and macroscopically unfractured matrix. The simulations show that secondary fractures contribute to retardation of solute, although their net effect is sensitive to assumptions regarding heterogeneity of transmissivity and transport aperture. Detailed results provide insight into the function of secondary fractures as an immobile domain affecting mass transfer on time scales relevant to

  5. 18 CFR 1304.407 - Development within flood control storage zones of TVA reservoirs.

    Science.gov (United States)

    2010-04-01

    ... flood control storage zones of TVA reservoirs. 1304.407 Section 1304.407 Conservation of Power and Water... zones of TVA reservoirs. (a) Activities involving development within the flood control storage zone on... flood control storage zones of TVA reservoirs shall be deemed an obstruction affecting navigation,...

  6. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  7. Shanghai's Development Zones

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Since the early 1980s,development zones began appearing in China.Their Success largely stems from the preferential policies they offer and the safe investment environment they work hard to create.As zones have personalities themselves,it is essential to look beyond the pamphlets and published information and get down to the nittygritty.Shanghai has more State designated Economic and Technology Development Zones than any other city in China.In the following article,we have chosen development zones located around Shanghai and conducted a comparison.

  8. Seismicity and Stress in the Southern Jalisco Block, Mexico.

    Science.gov (United States)

    Sánchez, J. J.; Núñez-Cornũ, F. J.

    2008-12-01

    Fault plane solutions for a group of 41 earthquakes with Mw magnitudes between 4.9 and 8.0, detected between November 1980 and May 2007, were extracted from the CMT catalog and used to investigate possible spatial and temporal variations of stress in the south part of the Jalisco Block. Using rigorous statistical tests we decide on the quality and variability of the earthquake source mechanisms and with the use of FMSI and LSIB stress tensor inversion techniques and cumulative misfit analysis find, at the 95% confidence level or more, significantly different regions and periods of stress regime. An important difference in seismicity and stress between the southern and northern regions of the Jalisco Block is highlighted by the regular occurrence of earthquakes to the south, in stark contrast with the scarcity of seismicity with Mw > 4.9 north of 19.36°N, a region that is illuminated with smaller earthquakes when local temporal or permanent deployments of seismographs are used, as noted by previous studies. We conclude that the region located near the coordinates 105°W and 18.43°N appears as a particularly diffuse zone affected by various stress styles and that the period following the great Mw 8.0 earthquake on October 9, 1995 appears as a short-lived change in stress induced by the great shock.

  9. Seismological investigations in the Gioia Tauro Basin (southern Calabria, Italy

    Directory of Open Access Journals (Sweden)

    S. Gresta

    2008-06-01

    Full Text Available This study provides new seismological information to characterize the seismically active area of the Gioia Tauro basin (southern Calabria, Italy. Seismic activity recorded by a temporary network from 1985 to 1994 was analyzed for focal mechanisms, stress tensor inversion, P-wave seismic attenuation and earthquake source parameters estimation. Fault plane solutions of selected events showed a variety of different mechanisms, even if a prevalence of normal dip-slip solutions with prevalent rupture orientations occurring along ca. NE-SW directions was observed. Stress tensor inversion analysis disclosed a region governed mainly by a NW-SE extensional stress regime with a nearly vertical ?1. These results are consistent with the structure movements affecting the studied area and with geodetic data. Furthermore, evaluation of P-waves seismic attenuation and earthquake source parameters of a subset of events highlighted a strong heterogeneity of the crust and the presence of fault segments and/or weakened zones where great stress accumulation or long-rupture propagation are hindered.

  10. Affective Urbanism

    DEFF Research Database (Denmark)

    Samson, Kristine

    . Under these circumstances affective aesthetics operate strategically within the urban field of interests, capital flows and desires of the social. This ‘affective urbanism’ (Anderson & Holden 2008) is linked to a society influenced by new kinds of information flows, where culture is mediated and enacted...... and cultural festivals, both practices indicate that design is implemented as means of creating affective spaces in the city. Both cases show how immaterial production of affects and emotions in the city can be seen in relation to economic potential and urban development. Finally, I will discuss whether urban......Urban design and architecture are increasingly used as material and affective strategies for setting the scene, for manipulation and the production of urban life: The orchestration of atmospheres, the framing and staging of urban actions, the programming for contemplation, involvement, play...

  11. Affective Maps

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    . In particular, mapping environmental damage, endangered species, and human made disasters has become one of the focal point of affective knowledge production. These ‘more-than-humangeographies’ practices include notions of species, space and territory, and movement towards a new political ecology. This type...... of environmental knowledge production. It uses InfoAmazonia, the databased platform on Amazon rainforests, as an example of affective geo-visualization within information mapping that enhances embodiment in the experience of the information. Amazonia is defined as a digitally created affective (map)space within...

  12. ZoneLib

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob; Schiøler, Henrik

    2006-01-01

    We present a dynamic model for climate in a livestock building divided into a number of zones, and a corresponding modular Simulink library (ZoneLib). While most literature in this area consider air flow as a control parameter we show how to model climate dynamics using actual control signals for...

  13. Bedrock structures controlling the spatial occurrence and geometry of 1.8 Ga younger glacifluvial deposits - Example from First Salpausselkä, southern Finland

    Science.gov (United States)

    Skyttä, Pietari; Kinnunen, Jussi; Palmu, Jukka-Pekka; Korkka-Niemi, Kirsti

    2015-12-01

    The glacifluvial deposits within formerly glaciated areas of southern Finland comprise the predominance of well-sorted subglacial and ice marginal sediments. The deposits are less than 100 m thick and form significant aquifers utilized by the respective areas. The spatial correlation of subglacial deposits with bedrock structures, particularly the deformation zones, has been long recognized, but most often not systematically investigated. The purpose of this study was to understand how specific bedrock structures control the position and processes of formation of glacifluvial deposits, using the First Salpausselkä area of southern Finland as a model area. We apply a means of structural analysis to compile structural interpretations (form lines and 3D-surfaces) of the bedrock and correlate the results with the patterns of the glacifluvial deposits and the topography of the underlying bedrock surface. Two major E-W striking shear zones defining abrupt breaks at the bedrock surface along with secondary SW-NE striking splays, originating from the horsetail-like termination of the Somero shear zone, control the deposition of eskers and ice marginal deposits. Based on correlations between the bedrock topography, glacial erosion and sedimentation, we infer that laterally extensive shear zones may have indirectly affected the glacial dynamics within the areas of areal scour more than previously considered. Recognized deformation zones are important for modelling the internal stratigraphy of glacifluvial deposits, their hydrogeological properties and for mapping fresh water supplies within the Nordic countries and other glaciated areas which have undergone substantial tectonic deformation. The development of 3D geologic models is essential for understanding regional-scale correlations between Quaternary sediments and bedrock structures.

  14. Understanding the South Pacific Convergence Zone and Its Impacts

    Science.gov (United States)

    Power, Scott

    2011-02-01

    International Workshop on the South Pacific Convergence Zone; Apia, Samoa, 24-26 August 2010 ; During the Southern Hemisphere summer the South Pacific Convergence Zone (SPCZ) in the southwestern Pacific Ocean produces the largest rainfall band in the world. The SPCZ tends to move northeast during southern winter and El Niño and move southwest during southern summer and La Niña. These changes in position have a profound influence on climate (e.g., rainfall, winds, and tropical cyclone frequencies) and life in most of the nations in the southwestern Pacific. Despite the importance of the SPCZ to the region and its prominence in the general circulation of the Southern Hemisphere, the SPCZ has been studied relatively little compared with convergence zones in the Northern Hemisphere. An international workshop on the SPCZ was held in Samoa and brought together 30 experts from Australia, the Cook Islands, Fiji, France, India, New Caledonia, New Zealand, Samoa, the Solomon Islands, Tonga, Tuvalu, the United Kingdom, the United States, and Vanuatu.

  15. Multilingualism in Southern Africa.

    Science.gov (United States)

    Peirce, Bonny Norton; Ridge, Stanley G. M.

    1997-01-01

    Reviews recent research in multilingualism in Southern Africa, focusing on the role of languages in education, sociolinguistics, and language policy. Much of the research is on South Africa. Topics discussed include language of instruction in schools, teacher education, higher education, adult literacy, language contact, gender and linguistic…

  16. Southern (In)hospitality

    Science.gov (United States)

    Hamilton, Kendra

    2005-01-01

    This article presents the results of "The Status of Race Equity and Diversity in Public Higher Education in the South," an analysis of trends in admissions, enrollment and completion at public colleges and universities in the 19 Southern and border states that maintained segregated systems of higher education in 1954. While work on the project…

  17. Ethnographies of Grey Zones in Eastern Europe:

    DEFF Research Database (Denmark)

    ’ and internationally minded ‘new citizens’ has left some in poverty, unemployment and social insecurity, leading them to rely on normative coping and semi-autonomous strategies for security and social guarantees. This anthology explores how grey zones of governance, borders, relations and invisibilities affect...

  18. Low- to high-grade metamorphic transition in the Southern part of Karnataka Nucleus, India

    Science.gov (United States)

    Naqvi, S. M.

    The southern part of Karnataka Nucleus has a strong imprint of 2.6 Ga metamorphism. This has affected the schist belts of Karnataka Nucleus from greenschist to upper amphibolite facies. The higher grades of metamorphism are in the Holenarasipur, Nuggihalli, Krishnarajpet, Hadnur and Melkote schist belts. In the high grade transition zone, around Sargur only keels of schist belts are preserved and occur as highly dismembered, disconnected belts with the top and bottom of the stratigraphic column obliterated due to high grade metamorphism and accompanying migmatization. Absence of high-grade metamorphic minerals in the sediments of the Dharwar schist belts supports the contention that high grade metamorphism post-dated the Dharwar sedimentation and occurred around 2.6 Ga ago. Sargur type metamorphism occurred at upper crustal levels and charnockite type metamorphism occurred in lower crustal levels. The P-T conditions for the mineral assemblage in metapelites of Sargur Group indicate burial depths up to at least 15 km suggesting that they were subducted and later obducted during the development of Early Proterozoic Mobile Belt along the southern border of the Karnataka Nucleus.

  19. Apple production and quality when cultivated under anti-hail cover in Southern Brazil

    Science.gov (United States)

    Bosco, Leosane Cristina; Bergamaschi, Homero; Cardoso, Loana Silveira; de Paula, Viviane Aires; Marodin, Gilmar Arduino Bettio; Nachtigall, Gilmar Ribeiro

    2015-07-01

    Anti-hail nets may change the microclimate of orchards and hence modify the physicochemical and sensory characteristics of fruits. The present study aimed to evaluate the effects of anti-hail nets on the physical, chemical, and sensory attributes of apples grown in southern Brazil. The study was conducted in commercial orchards, with apples grown under a black anti-hail net under an open sky during the 2008/2009, 2009/2010, and 2010/2011 cycles. Measurements of photosynthetically active radiation were collected at both sites. Physical, chemical, and sensory analyses of fruits were performed in the laboratory. The anti-hail net reduced incident photosynthetically active radiation by 32 %. The light spectrum in the canopy changed the corresponding R/FR (red/far-red) ratio in the lower and upper canopy layers from 0.27 to 1.55, respectively. In contrast to the majority of microclimate studies carried out in the temperate zones of the northern hemisphere, this study in the southern hemisphere showed that although it reduced the incident solar radiation, the cover did not change the color or organoleptic characteristics of "Royal Gala" and "Fuji Suprema" apples. The net cover prolonged the subperiod between fruit setting and harvesting, thus slowing fruit ripening. Therefore, the use of anti-hail nets on apple orchards is a suitable alternative for the protection of apple trees against hail because it causes only small changes in the microclimate and in the maturation period, ensuring fruit production without affecting its quality.

  20. Socio-economic analysis of conservation agriculture in southern Africa

    OpenAIRE

    Food and Agriculture Organization of the United Nations.‏ United Nations Development Programme

    2011-01-01

    Southern Africa, a region little affected by the Green Revolution and likely to suffer severe detrimental impacts from climate change, faces pervasive poverty, hunger, and environmental degradation. Conservation agriculture may be a sustainable and effective way to resolve these issues, but stakeholders need accessible and solid evidence of its effectiveness. The purpose of this report is to analyze the impact of CA on the Southern Africans countries of South Africa, Zambia, and Zimbabwe thro...

  1. Three-Dimensional Thermal Model of the Costa Rica-Nicaragua Subduction Zone

    Science.gov (United States)

    Rosas, Juan Carlos; Currie, Claire A.; He, Jiangheng

    2015-10-01

    The thermal structure of a subduction zone controls many key processes, including subducting plate metamorphism and dehydration, the megathrust earthquake seismogenic zone and volcanic arc magmatism. Here, we present the first three-dimensional (3D), steady-state kinematic-dynamic thermal model for the Costa Rica-Nicaragua subduction zone. The model consists of the subducting Cocos plate, the overriding Caribbean Plate, and a viscous mantle wedge in which flow is driven by interactions with the downgoing slab. The Cocos plate geometry includes along-strike variations in slab dip, which induce along-strike flow in the mantle wedge. Along-strike flow occurs primarily below Costa Rica, with a maximum magnitude of 4 cm/year (~40 % of the convergence rate) for a mantle with a dislocation creep rheology; an isoviscous mantle has lower velocities. Along-margin flow causes temperatures variations of up to 80 °C in the subducting slab and mantle wedge at the volcanic arc and backarc. The 3D effects do not strongly alter the shallow (Nicaragua; the narrow width in the north is due to hydrothermal cooling of the oceanic plate. These results are in good agreement with previous 2D models and with the rupture area of recent earthquakes. In the models, along-strike mantle flow is induced only by variations in slab dip, with flow directed toward the south where the dip angle is smallest. In contrast, geochemical and seismic observations suggest a northward flow of 6-19 cm/year. We do not observe this in our models, suggesting that northward flow may be driven by additional factors, such as slab rollback or proximity to a slab edge (slab window). Such high velocities may significantly affect the thermal structure, especially at the southern end of the subduction zone. In this area, 3D models that include slab rollback and a slab edge are needed to investigate the mantle structure and dynamics.

  2. Three-dimensional geometry and tectonostratigraphy of the Pennine zone, Central Alps, Switzerland and Northern Italy

    Science.gov (United States)

    Maxelon, Michael; Mancktelow, Neil S.

    2005-08-01

    Continental collision during Alpine orogenesis entailed a polyphase deformation history (D 1-D 5) in the Pennine zone of the Central Alps. The regional tectonostratigraphy was basically developed during D 1 and D 2, characterised by isoclinal, typically north-closing recumbent anticlines, separated by pinched-in synclines, on the scale of tens of kilometres. Later deformation phases (D 3 and D 4) warped the stack into wavy to open folds. Exhumation of this zone resulted locally in later vertical shortening and folding of already steep fabrics (D 5). Three-dimensional models of the nappe pile were constructed, based on geostatistical assessment of the regional foliation field and considering the abundant structural field data. These models indicate the existence of five principal tectonostratigraphic levels developed during D 1 and thus equivalent to nappe units s. str.: the Gotthard, the Leventina-Antigorio, the Maggia-Simano (and probably the Monte Leone as well as the Composite Lepontine Series), Lebendun-Soja and Adula-Cima Lunga levels. All these tectonic units formed part of the passive continental margin of Europe prior to the onset of the Alpine orogenesis. Individual isoclinal post-nappe folds reflect relative displacements on the order of 40 km or more. The most prominent D 2 post-nappe structure is the Wandfluhhorn Fold, structurally equivalent to the northern closure of the Leventina-Lucomagno Antiform. The Lebendun and Monte Leone folds are of similar magnitudes and also affect the whole nappe pile, whereas the smaller Mogno and Molare synforms only refold the Maggia-Simano nappe internally. Principal D 3 and D 4 structures are the tight Mergoscia Synform directly north of the Insubric Fault between Bellinzona and Locarno (Southern Steep Belt), the Maggia Steep Zone, forming the steep western limb of the Campo Tencia Synform and subdividing the Lepontine dome into the Simplon and Ticino subdomes, the Chiéra Synform steepening the dominant foliation in

  3. Reflection of block neotectonics in geological structure of paleogene strata of Chornobyl exclusion zone

    International Nuclear Information System (INIS)

    Neotectonic block differentiation of Chernobyl Exclusion zone area was fixed by the results of the geological and structure analysis of paleogene strata in complex with the space survey data interpretation. Structural plan of the latest tectonic movements had a block character; it was shown by the fracture systems, which represent the components of known regional tectonic zones of various trends and are found in the features of phanerozoic rock mass structure. The territory under study is divided into two parts - the northern one, where in the neotectonic movements are generally more intensive with manifestation practically all over the fracture zones, and the southern part, where in the newest breaks belong mainly to submeridional also to south-western regional fracture zones. The southern part of the Exclusion zone, as a whole, holds the greatest promise by comparison with the northern one in the view of neotectonic criteria regarding the geological repository siting for radioactive waste disposal

  4. Southern Taiwan - an Evolving "Coastal Range"?

    Science.gov (United States)

    Wu, F. T.; McIntosh, K.; Lavier, L. L.

    2008-12-01

    As a part of the TAIGER research, existing tectonic concepts are continuously being reviewed in light of new data and for experimental design. One of the critical areas for understanding the tectonics of Taiwan is southern Taiwan. Seismicity and recent tomographic imaging confirm that the tectonics of Taiwan is controlled by the subduction and collision of two plates: the Philippine Sea plate (PSP) and the Eurasian plate (EUR). In northern and central Taiwan the PSP is in collision with EUR, and at the same time subducts northward under northern Taiwan [Wu et al., 2008]. Before the PSP subducts to sufficient depth, the collision of PSP and EUR produced the Foothills and the Central Range on the EUR and the Coastal Range on the PSP side. For southern Taiwan, with 22.7°N as a rough demarcation, the tectonic interpretation is at variance and still in debate. To the east of southern Taiwan the inactive andesitic volcanic islands of Lutao and Lanhsu mark the top of the Luzon arc, separated from Taiwan by a somewhat deformed fore-arc basin [McIntosh et al., 2005]. To its west the Manila Trench is the western limit of a series of trend-parallel small thrusts on the ocean floor [Lunberg et al., 1997]. As the Trench approaches the continental shelf from the south it gradually loses its bathymetric signature. Southern Taiwan itself is commonly viewed as a part of the accretionary prism, and yet is also considered a continuation of the Central Range, produced by the collision of the Luzon arc and continental shelf. Suppe [1981] and many others had long recognized the central Taiwan orogeny, as a result of the collision of the Luzon Arc with the EUR continental shelf and Central Range, is built from rocks of the continental shelf. Inspection of a map of bathymetry around Taiwan shows that the continental shelf turns noticeably westward offshore of southwestern Taiwan, and that southern Taiwan is situated off the continental shelf. The presence of the Benioff zone under

  5. Affect Regulation

    DEFF Research Database (Denmark)

    Pedersen, Signe Holm; Poulsen, Stig Bernt; Lunn, Susanne

    2014-01-01

    Gergely and colleagues’ state that their Social Biofeedback Theory of Parental Affect Mirroring” can be seen as a kind of operationalization of the classical psychoanalytic concepts of holding, containing and mirroring. This article examines to what extent the social biofeedback theory of parenta...

  6. Study of thermal stress in heat affected zones during welding

    International Nuclear Information System (INIS)

    The importance of applications of welding in the nuclear industry leads to the study of the main problem concerning metal welding: sensibility to cracking. The development of computation methods allows the numerical simulation of welding effects. Due to the complexity of this problem, it is divided in three steps: thermal, metallurgical and mechanical calculus. Interactions between the 3 steps are examined. Mathematical models necessary to get residual stress (i.e. stress remaining when welding is completed and structure at ambient temperature) are described. Then parameters for metallurgical structure determination are given and compared to experiments. A508 and A533 type steels of primary coolant circuit of PWR reactors are taken as examples and the numerical simulation of a test is presented

  7. BLM Solar Energy Zones

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Priority development areas for utility-scale solar energy facilities as identified in the Solar PEIS Record of Decision. An additional Solar Energy Zone identified...

  8. Phase zone photon sieve

    Institute of Scientific and Technical Information of China (English)

    Jia Jia; Xie Chang-Qing

    2009-01-01

    A novel diffractive optical element, named phase zone photon sieve (PZPS), is presented. There are three kinds of phase plates in PZPSs: PZPS1, PZPS2, and PZPS3. Each of the PZPSs has its own structure and is made on quartz substrate by etching. The three PZPSs have stronger diffraction peak intensity than a photon sieve (PS) when the margin pinhole and zone line width are kept the same. The PZPS3 can produce a smaller central diffractive spot than the ordinary PS with the same number of zones on the Fresnel zone plate. We have given the design method for and the simulation of PZPS and PS. PZPS has potential applications in optical maskless lithography.

  9. : Seizure onset zone imaging

    OpenAIRE

    David, Olivier; Blauwblomme, Thomas; Job, Anne-Sophie; Chabardès, Stéphan; Hoffmann, Dominique,; Minotti, Lorella; Kahane, Philippe

    2011-01-01

    International audience Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we re...

  10. GEODYNAMICS OF NAZCA RIDGE’S OBLIQUE SUBDUCTION AND MIGRATION - IMPLICATIONS FOR TSUNAMI GENERATION ALONG CENTRAL AND SOUTHERN PERU: Earthquake and Tsunami of 23 June 2001

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis

    2012-01-01

    Full Text Available Peru is in a region of considerable geologic and seismic complexity. Thrust faulting along the boundary where the Nazca plate subducts beneath the South American continent has created three distinct seismic zones. The angle of subduction of the Nazca oceanic plate beneath the South American plate is not uniform along the entire segment of the Peru-Chile Trench. Furthermore, subduction is affected by buoyancy forces of the bounding oceanic ridges and fractures - such as the Mendana Fracture Zone (MFZ to the North and the Nazca Ridge to the South. This narrow zone is characterized by shallow earthquakes that can generate destructive tsunamis of varied intensities. The present study examines the significance of Nazca Ridge’s oblique subduction and migration to the seismicity of Central/Southern Peru and to tsunami generation. The large tsunamigenic earthquake of 23 June 2001 is presented as a case study. This event generated a destructive, local tsunami that struck Peru’s southern coasts with waves ranging from 3 to 4.6 meters (10-15 feet and inland inundation that ranged from 1 to 3 km. In order to understand the near and far-field tsunamigenic efficiency of events along Central/Southern Peru and the significance of Nazca Ridge’s oblique subduction, the present study examines further the geologic structure of the region and this quake’s moment tensor analysis, energy release, fault rupture and the spatial distribution of aftershocks. Tsunami source mechanism characteristics for this event are presented, as inferred from seismic intensities, energy releases, fault plane solutions and the use of empirical relationships. The study concludes that the segment of subduction and faulting paralleling the Peru-Chile Trench from about 150 to 180 South, as well as the obliquity of convergent tectonic plate collision in this region, may be the reason for shorter rupture lengths of major earthquakes and the generation of only local destructive tsunamis.

  11. The influences of the parameters in the welding process to the refinement of the zone by affected the temperature in the Cr-Mo-V steels; Influencia de los parametros del proceso de soldadura a la refinacion de la zona afectada por la temperatura en los aceros al Cr-Mo-V

    Energy Technology Data Exchange (ETDEWEB)

    Mazur Czerwiec, Zdzislaw

    2001-07-01

    The Cr-Mo-V fissure of the unions by welding that operate at high temperature and elevated pressure is an important problem. The behavior of the unions by welding in both cases during the process of welding and during its operation, depends strictly on the microstructure of the zone affected by the temperature (ZAT) of the base metal, which for a given chemical composition of the material it is a function of the weld parameters and geometry of the union. A prediction methodology of the microstructure of the zone affected by the temperature (ZAT) in a fillet weld applied to the low alloy steel 1.25 Cr-1 Mo-0.25 V by the process of weld with protected electrical arc (SMAW) is presented. The bases for the development of the algorithm were the classic equations of heat transference to determine the welding thermal cycles, basic metallurgy including transformation of the phases and grains' growth, empirical relations to describe the correlation of the variables of the weld process and the dimensions of the weld fillet. By means of an experiment, it was analyzed and determined the variation of the geometry of the singular weld fillet applied to the 1.25 Cr-1 Mo-0.25 V steel by means of the SMAW process and the microstructure of the zone affected by the temperature (ZAT) based in function of the heat induction and the preheating temperature. The empirical results were used for the numerical prediction of the microstructure of the zone affected by the temperature (ZAT) based on the weld parameters. It was found that the prediction methodology of the microstructure of the zone affected by the temperature (ZAT) in a fillet weld applied to a heavy plate of the low alloy steel 1.25 Cr-1 Mo-0.25 V by the SMAW process, with base in the knowledge of the dimensions of the weld fillet variables of the weld process and basic metallurgy of the ZAT, predicts the distribution of the microstructure in the reasonable ZAT for certain parameters of the weld. It was also found that the

  12. Bathymetry of southern Mauna Loa Volcano, Hawaii

    Science.gov (United States)

    Chadwick, William W.; Moore, James G.; Garcia, Michael O.; Fox, Christopher G.

    1993-01-01

    Manua Loa, the largest volcano on Earth, lies largely beneath the sea, and until recently only generalized bathymetry of this giant volcano was available. However, within the last two decades, the development of multibeam sonar and the improvement of satellite systems (Global Positioning System) have increased the availability of precise bathymetric mapping. This map combines topography of the subaerial southern part of the volcano with modern multibeam bathymetric data from the south submarine flank. The map includes the summit caldera of Mauna Loa Volcano and the entire length of the 100-km-long southwest rift zone that is marked by a much more pronounced ridge below sea level than above. The 60-km-long segment of the rift zone abruptly changes trend from southwest to south 30 km from the summit. It extends from this bend out to sea at the south cape of the island (Kalae) to 4 to 4.5 km depth where it impinges on the elongate west ridge of Apuupuu Seamount. The west submarine flank of the rift-zone ridge connects with the Kahuku fault on land and both are part of the ampitheater head of a major submarine landslide (Lipman and others, 1990; Moore and Clague, 1992). Two pre-Hawaiian volcanic seamounts in the map area, Apuupuu and Dana Seamounts, are apparently Cretaceous in age and are somewhat younger than the Cretaceous oceanic crust on which they are built.

  13. Flood susceptibility assessment in a highly urbanized alluvial fan: the case study of Sala Consilina (southern Italy

    Directory of Open Access Journals (Sweden)

    N. Santangelo

    2011-10-01

    Full Text Available This paper deals with the risk assessment to alluvial fan flooding at the piedmont zone of carbonate massifs of the southern Apennines chain (southern Italy. These areas are prime spots for urban development and are generally considered to be safer than the valley floors. As a result, villages and towns have been built on alluvial fans which, during intense storms, may be affected by flooding and/or debris flow processes.

    The study area is located at the foothills of the Maddalena mountains, an elongated NW-SE trending ridge which bounds to the east the wide intermontane basin of Vallo di Diano. The area comprises a wide detrital talus (bajada made up by coalescent alluvial fans, ranging in age from the Middle Pleistocene to the Holocene. Historical analysis was carried out to ascertain the state of activity of the fans and to identify and map the zones most hit by past flooding. According to the information gathered, the Sala Consilina fans would appear prone to debris flows; in the past these processes have produced extensive damage and loss of life in the urban area. The watershed basins feeding the fans have very low response times and may produce debris flow events with high magnitudes. Taking into account the historical damage, the fan surface morphology, and the present urban development (street orientation and hydraulic network, the piedmont area was zoned and various susceptibility classes were detected. These results may represent a useful tool for studies aiming at territorial hazard mapping and civil protection interventions.

  14. Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean

    Science.gov (United States)

    Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf

    2016-08-01

    Sea surface temperatures and sea-ice extent are most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 and ocean-atmosphere circulation. Here we present diatom transfer function-based summer sea surface temperature (SSST) and winter sea-ice (WSI) estimates from the Pacific sector of the Southern Ocean to bridge a gap in information that has to date hampered a well-established reconstruction of the last glacial Southern Ocean at circum-Antarctic scale. We studied the Last Glacial Maximum (LGM) at the EPILOG time slice (19,000-23,000 calendar years before present) in 17 cores and consolidated our LGM picture of the Pacific sector taking into account published data from its warmer regions. Our data display a distinct east-west differentiation with a rather stable WSI edge north of the Pacific-Antarctic Ridge in the Ross Sea sector and a more variable WSI extent over the Amundsen Abyssal Plain. The zone of maximum cooling (>4 K) during the LGM is in the present Subantarctic Zone and bounded to its south by the 4 °C isotherm. The isotherm is in the SSST range prevailing at the modern Antarctic Polar Front, representing a circum-Antarctic feature, and marks the northern edge of the glacial Antarctic Circumpolar Current (ACC). The northward deflection of colder than modern surface waters along the South American continent led to a significant cooling of the glacial Humboldt Current surface waters (4-8 K), which affected the temperature regimes as far north as tropical latitudes. The glacial reduction of ACC temperatures may also have resulted in significant cooling in the Atlantic and Indian Southern Ocean, thus enhancing thermal differentiation of the Southern Ocean and Antarctic continental cooling. The comparison with numerical temperature and sea-ice simulations yields discrepancies, especially concerning the estimates of the sea-ice fields, but some simulations

  15. Affective Networks

    Directory of Open Access Journals (Sweden)

    Jodi Dean

    2010-02-01

    Full Text Available This article sets out the idea of affective networks as a constitutive feature of communicative capitalism. It explores the circulation of intensities in contemporary information and communication networks, arguing that this circulation should be theorized in terms of the psychoanalytic notion of the drive. The article includes critical engagements with theorists such as Guy Debord, Jacques Lacan, Tiziana Terranova, and Slavoj Zizek.

  16. Astrophysics in Southern Africa

    CERN Document Server

    Whitelock, Patricia A

    2007-01-01

    The government of South Africa has identified astronomy as a field in which their country has a strategic advantage and is consequently investing very significantly in astronomical infrastructure. South Africa now operates a 10-m class optical telescope, the Southern African Large Telescope (SALT), and is one of two countries short listed to host the Square Kilometre Array (SKA), an ambitious international project to construct a radio telescope with a sensitivity one hundred times that of any existing telescope. The challenge now is to produce an indigenous community of users for these facilities, particularly from among the black population which was severely disadvantaged under the apartheid regime. In this paper I briefly describe the observing facilities in Southern Africa before going on to discuss the various collaborations that are allowing us to use astronomy as a tool for development, and at the same time to train a new generation of astronomers who will be well grounded in the science and linked to ...

  17. Regional Variation in Lytic and Lysogenic Viral Infection in the Southern Ocean and Its Contribution to Biogeochemical Cycling

    NARCIS (Netherlands)

    Evans, C.; Brussaard, C.P.D.

    2012-01-01

    Lytic and lysogenic viral infection was investigated throughout the Southern Ocean at sites spanning the sub-Antarctic zone, the Antarctic Circumpolar Current, and an Antarctic continental sea. Higher lytic virus activity was recorded in the more productive sub-Antarctic zone than in the iron-limite

  18. Thermal fronts and cross-frontal heat flux in the southern Huanghai Sea and the East China Sea

    Institute of Scientific and Technical Information of China (English)

    PARK Sunghyea; CHU Peter C

    2008-01-01

    Synoptic features in/around thermal fronts and cross-frontal heat fluxes in the southern Huanghai/Yellow Sea and East China Sea(HES) were examined using the data collected from four airborne expendable bathythermograph surveys with horizontal approxmately 35 km and vertical 1 m( from the surface to 400 m deep) spacings. Since the fronts are strongly affected by HES current system, the synoptic thermal features in/around them represent the interaction of currents with surrounding water masses. These features can not be obtained from climatological data. The identified thermal features are listed as follows: (1) multiple boundaries of cold water, asymmetric thermochne intrusion, locally-split front by homogeneous water of approxmately 18 ℃, and mergence of the front by the Taiwan Warm Current in/around summertime southern Cheju-Changjiang/Yangtze front and Tsushima front; (2) springtime frontal eddy-like feature around Tsnshima front; (3) year-round cyclonic meandering and summertime temperature-inversion at the bottom of the surface mixed layer in Cheju-Tsushima front; and (4) multistructure of Kuroshio front. In the Kureshio front the mean variance of vertical temperature gradient is an order of degree smaller than that in other HES fronts.The southern Cheju-Changjiang front and Cheju-Tsushima front are connected with each other in the summer with comparable cross-frontal temperature gradient. However, cross-frontal heat flux and lateral eddy diffusivity are stronger in the southern Cheju-Changjiang front. The cross-frontal heat exchange is the largest in the mixing zone between the modified Huanghai Sea bottom cold water and the Tsushima Warm Current, which is attributable to enhanced thermocline intrusions.

  19. Climate co-variability between South America and Southern Africa at interannual, intraseasonal and synoptic scales

    Science.gov (United States)

    Puaud, Yohan; Pohl, Benjamin; Fauchereau, Nicolas; Macron, Clémence; Beltrando, Gérard

    2016-08-01

    This paper investigates and quantifies co-variability between large-scale convection in the South American and Southern African sectors at different timescales (interannual, intraseasonal and synoptic), during the austral summer seasons (November-February) from 1979 to 2012. Multivariate analyses (Canonical Correlation Analysis and Principal Component Analysis) are applied to daily outgoing longwave radiation (OLR, used as a proxy for atmospheric convection) anomalies to extract the principal modes of variability and co-variability in each and between both regions, filtered to consider the appropriate time-scales. At the interannual timescale, results confirm the predominant role of El Niño Southern Oscillation (ENSO), favoring enhanced convection over both southeastern Brazil and northern Argentina on the one hand, and tropical Africa and the western Indian Ocean on the other hand. At the intraseasonal timescale, the leading mode of co-variability is related to modulations of large-scale atmospheric convection over most of South America, and 10 days later, tropical Southern Africa. This mode accounts for the impacts of the Madden-Julian-oscillation (MJO) over these regions: identifying robust co-variability at the intraseasonal timescale between both regions require thus to consider a temporal shift between the two sectors. At the synoptic scale, however, co-variability consists mostly of a synchronous modulation of the large-scale atmospheric convection over the South American and Southern African sectors. This results from the development of concomitant Rossby waves forming a continuous wave train over the South Atlantic in the mid-latitudes, affecting both the South Atlantic and South Indian Convergence Zones. Among the days when convection shows significant anomalies (30 % of the total days in each sector), this synchronous mode occurs about 25 % of the time, individual Rossby waves modulating convection over one single region only during the remaining 75

  20. Holocene climate variability in the winter rainfall zone of South Africa

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2013-10-01

    Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and δ18O and δ13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the winter rainfall zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 cal years BP most likely in response to a northward shift of the austral westerlies. Wet phases and strengthened coastal water upwellings are companied by a decrease of Agulhas water leakage into the South Atlantic and a reduced dust incursion over Antarctica, as indicated in previous studies. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS between 9000 and 5500 cal years BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the eastern South Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in the South Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation.

  1. Holocene climate variability in the winter rainfall zone of South Africa

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2012-06-01

    Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and δ18O and δ13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off Western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the Southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the Southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with evidence of a poleward shift of the austral mid-latitude westerlies and an enhanced leakage of warm Agulhas water into the Southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies and changes in the amount of Agulhas water leakage into the Southern BUS. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over Southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the Southern BUS may affect coastal fog formation that is

  2. The Freyenstein Shear Zone - Implications for exhumation of the South Bohemian Batholith (Moldanubian Superunit, Strudengau, Austria)

    Science.gov (United States)

    Griesmeier, Gerit; Iglseder, Christoph; Konstantin, Petrakakis

    2016-04-01

    The Moldanubian superunit is part of the internal zone of the Variscan Orogen in Europe and borders on the Saxothuringian and Sudetes zones in the north. In the south, it is blanketed by the Alpine foreland molasse. Tectonically it is subdivided into the Moldanubian Nappes (MN), the South Bohemian Batholith (SBB) and the Bavarian Nappes. This work describes the ~ 500 m thick Freyenstein shear zone, which is located at the southern border of the Bohemian Massif north and south of the Danube near Freyenstein (Strudengau, Lower Austria). The area is built up by granites of Weinsberg-type, which are interlayered by numerous dikes and paragneisses of the Ostrong nappe system. These dikes include medium grained granites and finegrained granites (Mauthausen-type granites), which form huge intrusions. In addition, smaller intrusions of dark, finegrained diorites und aplitic dikes are observed. These rocks are affected by the Freyenstein shear zone und ductily deformed. Highly deformed pegmatoides containing white mica crystals up to one cm cut through the deformed rocks and form the last dike generation. The Freyenstein shear zone is a NE-SW striking shear zone at the eastern edge of the SBB. The mylonitic foliation is dipping to the SE with angles around 60°. Shear-sense criteria like clast geometries, SĆ structures as well as microstructures show normal faulting top to S/SW with steep (ca. 50°) angles. The Freyenstein shear zone records a polyphase history of deformation and crystallization: In a first phase, mylonitized mineral assemblages in deformed granitoides can be observed, which consist of pre- to syntectonic muscovite-porphyroclasts and biotite as well as dynamically recrystallized potassium feldspar, plagioclase and quartz. The muscovite porphyroclasts often form mica fishes and show top to S/SW directed shear-sense. The lack of syntectonic chlorite crystals points to metamorphic conditions of lower amphibolite-facies > than 450° C. In a later stage fluid

  3. Geology of the Terra Cimmeria-Utopia Planitia Highland Lowland Transitional Zone: Final Technical Approach and Scientific Results

    Science.gov (United States)

    Skinner, J. A., Jr.; Tanaka, K. L.

    2010-01-01

    The southern Utopia highland-lowland transitional zone extends from northern Terra Cimmeria to southern Utopia Planitia and contains broad, bench-like platforms with depressions, pitted cones, tholi, and lobate flows. The locally occurring geologic units and landforms contrast other transitional regions and record a spatially partitioned geologic history. We systematically delineated and described the geologic units and landforms of the southern Utopia-Cimmeria highland-lowland transitional zone for the production of a 1:1,000,000-scale geologic map (MTMs 10237, 15237, 20237, 10242, 15242, 20242, 10247, 15247, and 20247). Herein, we present technical and scientific results of this mapping project.

  4. MICROSTRUCTURAL CHARACTERS AND TOUGHNESS OF DIFFERENT SUB-REGIONS IN THE WELDING HEAT AFFECTED ZONE OF LOW CARBON BAINITIC STEEL%低碳贝氏体钢焊接热影响区中不同亚区的组织特征与韧性

    Institute of Scientific and Technical Information of China (English)

    兰亮云; 邱春林; 赵德文; 李灿明; 高秀华; 杜林秀

    2011-01-01

    根据焊接热影响区中不同亚区的热循环特征对低碳贝氏体钢进行了焊接热模拟实验.采用示波器载荷冲击试验机检测焊接热模拟试样的冲击韧性,结合OM,SEM,TEM以及EBSD技术对模拟显微组织的观察,分析了不同亚区的显微组织特征与冲击韧性之间的关系.结果表明,当冷却时间ts/5=30 s时,各亚区的裂纹形核功相差并不太大,其值在40-70 J之间.细晶区(FGHAZ)具有良好的止裂能力,裂纹扩展功高达122 J;而部分相变区(ICHAZ)和粗晶区(CGHAZ)的裂纹扩展功较小,分别为51.8和17 J.随t8/5的延长,各亚区的裂纹形核功和扩展功均下降,其中CGHAZ的裂纹形核功和FGHAZ的裂纹扩展功的下降最为显著.不同冷却速率下,M-A组元尺寸和形态的变化是影响裂纹形核功的重要因素.对于裂纹扩展功来说,高冷却速率下,具有高密度大角晶界的FGHAZ具有良好的抗裂纹迅速扩展的能力,但当冷却速率降低,由于原始奥氏体晶粒长大而使裂纹扩展功下降.ICHAZ有效晶粒尺寸不均匀,并随冷却速率的降低,晶粒尺寸明显增大,裂纹扩展功下降.而在CGHAZ中原始奥氏体晶粒显著粗化,大角晶界密度的下降导致裂纹扩展功降低;随冷却速率的降低,原始奥氏体晶粒内的取向变得更为单一,裂纹扩展功进一步降低.%It is generally recognized that welding heat affected zone (WHAZ) is the poorest toughness region in the welded joint of low carbon bainitic steels. The thermomechanical simulator was employed to simulate the welding thermal cycle processes of different sub-regions in WHAZ of low carbon bainitic steel in this work. The toughness of simulated specimens were tested on the instrumented drop weight impact tester with oscilloscope, and miscrostructure features were observed by means of OM, SEM, TEM and EBSD. The results showed that when cooling time (t8/5) was 30 s, the crack initiation energy of various sub-regions was

  5. Ecological Construction Based on Land Use Zoning of Anhui Province

    Institute of Scientific and Technical Information of China (English)

    Xin; YE; Zhongxiang; YU

    2013-01-01

    Anhui Province is divided into 6 zones according to land use. This paper firstly introduces ranges, characteristics and problems of land use zoning in Anhui Province. On these bases, it presents the respective ecological construction mode. Huaibei Plain Zone should focus on agriculture and implement water conservancy project, ecological shelterbelt project and mining subsidence area control works. Jianghuai Hilly Zone should make breakthrough in transforming slope land, speed up restoring forest, grass and vegetation, and implement water-saving agriculture and prevention and control of soil erosion. The Yangtze River Side Plain Zone should take the opportunity of agricultural structural adjustment to implement the ecological construction mode of "reconverting farmland to forests, wetland and lakes". Western Anhui Dabie Mountain Zone should concentrate on setting apart hills for tree growing and transforming slope land, restoring and expanding forest, grass and vegetation, and implementing prevention and control of soil erosion. Southern Anhui Mountain Zone should focus on protecting natural forest, setting apart hills for tree growing, conceding the land to forestry and developing eco-tourism. Residential area should pay close attention to new urbanization construction, center on citizenship of agricultural population, push forward integration of industry and city, coordination of urban and rural areas, and interactive development of primary, secondary and tertiary industries.

  6. Fractal geometry and seismicity in the Mexican subduction zone

    OpenAIRE

    F. Angulo Brown; A. H. Ramírez Guzmán; Yépez, E.; A. Rudolf Navarro; C. G. Pavía Miller

    1998-01-01

    By means of the box counting method we calculate the fractal dimension D of the distribution of faults, fractures and lineaments in a region of the southern Mexican Pacific coast. The results suggest that in the spatial sense the b-value of the Gutenberg-Richter law and the fractal dimension are positively correlated. We also suggest that D depends on the depth of the seismogenic zone.

  7. Multispectral observations of the surf zone

    Science.gov (United States)

    Schoonmaker, Jon S.; Dirbas, Joseph; Gilbert, Gary

    2003-09-01

    Airborne multispectral imagery was collected over various targets on the beach and in the water in an attempt to characterize the surf zone environment with respect to electro-optical system capabilities and to assess the utility of very low cost, small multispectral systems in mine counter measures (MCM) and intelligence, surveillance and reconnaissance applications. The data was collected by PAR Government Systems Corporation (PGSC) at the Army Corps of Engineers Field Research Facility at Duck North Carolina and on the beaches of Camp Pendleton Marine Corps Base in Southern California. PGSC flew the first two of its MANTIS (Mission Adaptable Narrowband Tunable Imaging Sensor) systems. Both MANTIS systems were flown in an IR - red - green - blue (700, 600, 550, 480 nm) configuration from altitudes ranging from 200 to 700 meters. Data collected has been lightly analyzed and a surf zone index (SZI) defined and calculated. This index allows mine hunting system performance measurements in the surf zone to be normalized by environmental conditions. The SZI takes into account water clarity, wave energy, and foam persistence.

  8. "Redistribution" Effect of Lumpy Zone for Gas Flow in BF

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The gas flow from tuyere to raceway zone by blasting involves three distributional zones, such as dripping,cohesive, and lumpy zone. The gas flow distribution in lumpy zone directly affects the gas utilization ration and smooth operation in the blast furnace. However, the furnace closeness brings about great difficulty in the study of high-temperature gas flow. The charging and blasting system affecting the gas flow and whether the top gas flow distribution could reflect its inner condition as well as the furnace state, such as hanging or scaffolding, which have become the main problems for the research on gas flow. Recently, several researches overseas studied gas flow distribution using the numerical simulation method; however, such a research was rare amongst the natives. In this study, the flow model of gas in cohesive and lumpy zone was established using the numerical simulation software and the gas flow distributions with uniform distribution of burden permeability, scaffolding of wall, and nonuniform charge level were analyzed. As a result, the effects of cohesive zone and lower parts on the gas flow are very limited and the charge level largely affects the distribution of top gas flow. Therefore, it was found that the distribution of top gas flow could hardly reflect the inner gas flow. The process is called "redistribution" effect, which means that the gas flow after passing through the raceway, dripping, and cohesive zone is distributed when it flows into the lumpy zone.

  9. Contrasting metamorphism across Cauvery Shear Zone, south India

    Indian Academy of Sciences (India)

    Manish M John; S Balakrishnan; B K Bhadra

    2005-04-01

    The Palghat Cauvery Shear Zone (CSZ) is a major shear zone that possibly extends into different fragments of Gondwanaland. In the present study mafic granulites occurring on either side of the CSZ in Namakkal area, southern India are examined. Textural features recorded in the mafic granulites are crucial in elucidating the metamorphic history of the southern granulite terrane (SGT). In the mafic granulites occurring to the south of CSZ, evidence of garnet breaking down during near isothermal decompression (ITD) is indicated by the development of orthopyroxene + plagioclase moats in between quartz and garnet. The presence of comparatively small elongated second generation garnet embedded in pyroxenes from the mafic granulites occurring to the north of CSZ is indicative of the garnet formation via reaction between pyroxenes and plagioclase, which occurred during isobaric cooling (IBC). Rocks occurring to the south of CSZ have recorded comparatively higher temperature and pressure (849°C and 9.6 kbar) than those occurring to the north of the CSZ (731°C and 8.6 kbar) using conventional geothermobarometry. The rocks occurring to the north of CSZ have suffered more complex metamorphic histories in comparison to the southern part. Integrating the results of the present field and metamorphic studies with the earlier investigations and available geochronological data we suggest that the CSZ could represent a suture zone between two different continental blocks that underwent distinct metamorphic evolution.

  10. Zones of emotional labour

    DEFF Research Database (Denmark)

    Strøbæk, Pernille Solveig

    2011-01-01

    The paper suggests that due to the difficult nature of their work public family law caseworkers are to be included in the definition of emotional labour even though they are omitted by Hochschild. Based upon a review of the structures involved in emotional labour an explorative qualitative study is...... put forth among 25 Danish public family law caseworkers. The study points to personal, professional, and social zones of emotional labour through which the caseworkers carry out their work. Emotional labour zones mark emotion structures that may be challenging due to complex emotional intersections...

  11. Grid zone drone

    OpenAIRE

    McCarthy, Clive; Cooper, Graham; Field, James; Thayne, Martyn; Vickers, Richard

    2014-01-01

    From 16th – 19th October 2014, co_LAB presented its newest creation, Grid Zone Drone, at Kinetica – an international exhibition providing a global platform for galleries, curatorial groups, design studios and artists working with new media art. 2014 marked the third consecutive year that the University of Lincoln has been represented at the global art fair. Grid Zone Drone represents a continuation of the group’s research into ‘drone culture’, and explores the detachment of the drone withi...

  12. [Affective dependency].

    Science.gov (United States)

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy. PMID:23888587

  13. [Affective dependency].

    Science.gov (United States)

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  14. Flexural bending of southern Tibet in a retro foreland setting.

    Science.gov (United States)

    Wang, Erchie; Kamp, Peter J J; Xu, Ganqing; Hodges, Kip V; Meng, Kai; Chen, Lin; Wang, Gang; Luo, Hui

    2015-01-01

    The highest elevation of the Tibetan Plateau, lying 5,700 m above sea level, occurs within the part of the Lhasa block immediately north of the India-Tibet suture zone (Yarlung Zangbo suture zone, YZSZ), being 700 m higher than the maximum elevation of more northern parts of the plateau. Various mechanisms have been proposed to explain this differentially higher topography and the rock uplift that led to it, invoking crustal compression or extension. Here we present the results of structural investigations along the length of the high elevation belt and suture zone, which rather indicate flexural bending of the southern margin of the Lhasa block (Gangdese magmatic belt) and occurrence of an adjacent foreland basin (Kailas Basin), both elements resulting from supra-crustal loading of the Lhasa block by the Zangbo Complex (Indian plate rocks) via the Great Counter Thrust. Hence we interpret the differential elevation of the southern margin of the plateau as due originally to uplift of a forebulge in a retro foreland setting modified by subsequent processes. Identification of this flexural deformation has implications for early evolution of the India-Tibet continental collision zone, implying an initial (Late Oligocene) symmetrical architecture that subsequently transitioned into the present asymmetrical wedge architecture. PMID:26174578

  15. Millennial-scale sea ice expantion in the glacial Southern Ocean

    OpenAIRE

    池原, 実; 香月, 興太; 山根, 雅子; 横山, 祐典;