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Sample records for barberton greenstone belt

  1. Polyphase thrust tectonic in the Barberton greenstone belt

    Science.gov (United States)

    Paris, I. A.

    1986-01-01

    In the circa 3.5 by-old Barberton greenstone belt, the supracrustal rocks form a thick and strongly deformed thrust complex. Structural studies in the southern part of the belt have shown that 2 separate phases of over-thrusting (D sub 1 and D sub 2) successively dismembered the original stratigraphy. Thrust nappes were subsequently refolded during later deformations (D sub 3 and D sub 4). This report deals with the second thrusting event which, in the study region appears to be dominant, and (unlike the earlier thrusting), affects the entire supracrustal pile. The supracrustal rocks form a predominantly NE/SW oriented, SE dipping tectonic fan (the D sub 2 fan) in which tectonic slices of ophiolitic-like rocks are interleaved with younger sedimentary sequences of the Diepgezet and malalotcha groups. Structural and sedimentological data indicate that the D sub 2 tectonic fan was formed during a prolonged, multi-stage regional horizontal shortening event during which several types of internal deformation mechanisms were successively and/or simultaneously active. Movement appears to have been predominantly to the NW and to the N. During D sub 2, periods of quiescence and sedimentation followed periods of thrust propagation. Although the exact kinematics which led to the formation of this fan is not yet known, paleoenvironmental interpretations together with structural data suggest that D sub 2 was probably related to (an) Archean collision(s).

  2. Paleoarchean sulfur cycling : Multiple sulfur isotope constraints from the Barberton Greenstone Belt, South Africa

    NARCIS (Netherlands)

    Montinaro, Alice; Strauss, Harald; Mason, Paul R D; Roerdink, Desiree; Münker, Carsten; Schwarz-Schampera, Ulrich; Arndt, Nicholas T.; Farquhar, James; Beukes, Nicolas J.; Gutzmer, Jens; Peters, Marc

    2015-01-01

    Mass-dependent and mass-independent sulfur isotope fractionation archived in volcanic and sedimentary rocks from the Barberton Greenstone Belt (3550-3215. Ma), South Africa, provide constraints for sulfur cycling on the early Earth. Four different sample suites were studied: komatiites and tholeiite

  3. Petrography of Archean Spherule Layers from the CT3 Drill Core, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Hoehnel, D.; Reimold, W. U.; Mohr-Westheide, T.; Hofmann, A.; Altenberger, U.

    2016-08-01

    One of the major questions to be addressed in the core CT3 from the northeastern Barberton Greenstone Belt in South Africa is about the actual number of impact events represented by the 17 spherule layers over a stratigraphic interval of 150 m.

  4. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    Science.gov (United States)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  5. Paleoarchean Spherule Beds in the CT3 Drill Core from the Barberton Greenstone Belt, South Africa: Geochemistry and Os Isotopic Signatures

    Science.gov (United States)

    Ozdemir, S.; Schulz, T.; Koeberl, C.; Reimold, W. U.; Mohr-Westheide, T.; Hofmann, A.

    2016-08-01

    Archean spherules are important to understand the early Earth's impact history. We performed detailed petrographic, geochemical and Os isotope analysis to obtain possible meteoritic components on spherule layers from Barberton Greenstone Belt.

  6. Micro-XRF Analysis of Archean Spherule Layers and Host Rocks from the CT3 Drill Core, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Hoehnel, D.; Tagle, R.; Hofmann, A.; Reimold, W. U.; Mohr-Westheide, T.; Fritz, J.; Altenberger, U.

    2016-08-01

    Spherule layers and host rock samples from the Barberton Greenstone Belt were studied with a µ-XRF spectrometer. Elemental distribution maps indicate distinct folding that had been recognized neither by visual inspection nor by petrographic analysis.

  7. Germanium Elemental and Isotopic Tracing of ca 3.2 Ga Impact Spherule Layers from the Barberton Greenstone Belt (South Africa)

    Science.gov (United States)

    Luais, B.; Fritz, J.; Hofmann, A.; Mohr-Westheide, T.; Reimold, W. U.; Koeberl, C.

    2016-08-01

    The 3.23 Ga spherule layers in BARB5 drill core from the Barberton Greenstone Belt (ICDP 2012-2013, South Africa) have high Ge contents and light Ge isotopic signature that agree with an evaporation-condensation mechanism following the impact.

  8. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

    Directory of Open Access Journals (Sweden)

    M. Ledevin

    2014-05-01

    Full Text Available A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the

  9. Archean spherule classification of CT3 drill core, Barberton Greenstone Belt (South Africa) based on petrography and mineral chemistry

    Science.gov (United States)

    Ozdemir, Seda; Koeberl, Christian; Mohr-Westheide, Tanja; Reimold, W. Uwe; Hofmann, Axel

    2016-04-01

    The impact history of the Early Archean Earth is not well documented. The oldest known impact structure is about 2 Ga years old; impact-related signatures in Precambrian rocks are scarce. The possible impact signature might be the Archean spherule layers that occur in the Barberton Greenstone Belt (BGB), Kaapvaal Craton, South Africa, and in the Pilbara Craton Western Australia, with ages of 3.2-3.4 and around 2.5 Ga [1]. These spherules were interpreted as impact-generated and ballistically emplaced silicate melt droplets [2]. This study is focused on petrographic and mineralogical characteristics from a set of newly drilled Archean spherule layers in drill core CT3 from the northeastern part of the BGB. The investigation of the three main intervals (A, B, and C, which include 2, 13, and 2 individual spherule layers, respectively) within CT3, contains the classification of spherules based on their shapes, textural features, deformation types, and mineral content. All of the intervals show spherule variation in those features. Therefore, the classification helps to understand if the spherules underwent processes such as tectonic deformation or if multiple impact events occurred in the area, which both might a reason of spherule layer duplications. The aim of the work is to differentiate various spherule types and the groundmasses in which they are embedded. The spherules within 17 identified spherule layers have been examined by optical microscopy (polarized and reflected) and secondary electron microscopy and were classified by shape and textural features. Subsequently, mineral phases and the chemical composition of the spherules and their matrices were investigated by using electron microprobe analysis. Regarding the shapes of the spherules they were divided into two main groups: undeformed and deformed. Undeformed spherules have spherical to ovoid as well as tear-drop shapes; deformed spherules were further subdivided into three main groups; flattened, crushed

  10. Compositional Grading in an Impact-produced Spherule Bed, Barberton Greenstone Belt, South Africa: A Key to Condensation History of Rock Vapor Clouds

    Science.gov (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.

    2003-01-01

    The chemical and physical processes by which spherules form during the condensation of impact-produced rock vapor clouds are poorly understood. Although efforts have been made to model the processes of spherule formation, there is presently a paucity of field data to constrain the resulting theoretical models. The present study examines the vertical compositional variability in a single early Archean spherule bed in the Barberton Greenstone Belt (BGB), South Africa, in order to better identify the process by which impact vapor clouds condense and spherules form and accumulate. The BGB spherule beds are suitable for this type of study because of their great thickness, often exceeding 25cm of pure spherules, due to the massive sizes of the impactors. Two main problems complicate analysis of vertical compositional variability of graded spherule beds: (1) differential settling of particles in both the vapor and water column due to density and size differences and (2) turbulence within the vapor cloud. The present study compares sections of spherule bed S3 from four different depositional environments in the Barberton Greenstone Belt: (1) The Sheba Mine section (SAF-381) was deposited under fairly low energy conditions in deep water, providing a nice fallout sequence, and also has abundant Ni-rich spinels; (2) Jay's Chert section (SAF-380) was deposited in subaerial to shallow-water conditions with extensive post-depositional reworking by currents. The spherules also have preserved spinels; (3) the Loop Road section (loc. SAF-295; samp. KSA-7) was moderately reworked and has only rare preservation of spinels; and (4) the shallow-water Barite Syncline section (loc. SAF-206; samp KSA-1) has few to no spinels preserved and is not reworked. Although all of the spherule beds have been altered by silica diagenesis and K-metasomatism, most of the compositional differences between these sections appear to reflect their diagenetic histories, possibly related to their differing

  11. Inferred Primary Compositions of Archean Spherules Formed by the Condensation of an Impact-produced Rock Vapor Cloud, Barberton Greenstone Belt, South Africa

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    Krull, A. E.; Lowe, D. R.; Byerly, G. R.

    2003-01-01

    Based on the lunar cratering record, impacts were larger and more frequent on the early Earth than they are today. There is no persevered record of these early terrestrial impacts because rocks of this age have been obliterated by tectonism and erosion. The oldest known evidence of impacts on Earth lies in four beds (S1, S2, S3 and S4) in the Barberton Greenstone Belt (BGB), South Africa, ranging in age from about 3.24 to 3.47 Ga. These beds are composed in large part of sand-sized spherical particles, termed spherules, that are thought to have formed by the condensation of rock vapor clouds ejected above the atmosphere as a result of large impacts. Spherule beds S2 and S3 are both about 20 cm thick where composed entirely of fall-deposited spherules and up to a meter thick where spherules are mixed with locally derived debris. The diameters the bolides have been estimated to be between 20 and 50 km, based on bed thickness, size of the largest spherules, Ir fluence and extraterrestrial Cr.

  12. Archean deep-water depositional system: interbedded and banded iron formation and clastic turbidites in the Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Zentner, Danielle; Lowe, Donald

    2013-04-01

    The 3.23 billion year old sediments in the Barberton greenstone belt, South Africa include some of the world's oldest known deep-water deposits. Unique to this locality are turbidites interbedded with banded iron formation (BIF) and banded ferruginous chert (BFC). This unusual association may provide clues for reconstructing Archean deep-water depositional settings. For our study we examined freshly drilled core in addition to measuring ~500 m of outcrop exposures along road cuts. The stacking pattern follows an overall BIF to BFC to amalgamated turbidite succession, although isolated turbidites do occur throughout the sequence. The turbidites are predominately massive, and capped with thin, normally graded tops that include mud rip-ups, chert plates, and ripples. The lack of internal stratification and the amalgamated character suggests emplacement by surging high-density turbidity currents. Large scours and channels are absent and bedding is tabular: the flows were collapsing with little turbulence reaching the bed. In contrast, field evidence indicates the BIF and BFC most likely precipitated directly out of the water column. Preliminary interpretations indicate the deposits may be related to a pro-deltaic setting. (1) Deltaic systems can generate long-lived, high volume turbidity currents. (2) The contacts between the BIF, BFC, and turbidite successions are gradual and inter-fingered, possibly representing lateral facies relationships similar to modern pro-delta environments. (3) Putative fan delta facies, including amalgamated sandstone and conglomerate, exist stratigraphically updip of the basinal sediments.

  13. Investigating traces of early life in the oldest tectono-sedimentary basin of the 3.5 - 3.1 Ga Barberton greenstone belt, South Africa

    Science.gov (United States)

    Grosch, Eugene

    2014-05-01

    The ca. 3.5 - 3.1 Ga Barberton greenstone belt (BGB) in the Kaapvaal Craton of South Africa, contains some of the world's best preserved sequences of volcano-sedimentary and mafic-ultramafic rocks representative of the Paleoarchean. These rocks provide a unique opportunity to investigate dynamic environments and possible evidence for life on the young Earth. Evidence for early microbial life has been argued to be preserved in silicified marine sediments (cherts) and subseafloor pillow lavas of the upper Onverwacht Group of the BGB. This study will focus on the ca. 3.472 - 3.334 Ga Hooggenoeg, Noisy and Kromberg Formations argued to contain textural, geochemical and isotopic evidence for the oldest traces of subseafloor life on Earth. These include filamentous titanite microtextures as candidate 'ichnofossils', X-ray maps of carbon linings associated with these microtextures and negative carbon stable isotope ratios in Archean pillow lava rims (Furnes et al., 2004, 2008; Banerjee et al., 2006). Based on previously reported similarity between these titanite microtextures and partially mineralized microtubes found in altered in-situ oceanic crust, a complex 'bioalteration' model has been proposed, involving microbial-mediated alteration of basaltic glass. Despite numerous claims for the exceptional preservation of early subseafloor alteration in the proposed 'Biomarker' type-section, constraints on the nature and timing of low-temperature alteration are not available for the Hooggenoeg Formation. In this talk, new field and petrological data from the mafic-ultramafic Kromberg, volcano-sedimentary Noisy, and dominantly mafic Hooggenoeg Formations in the southeastern part of the Onverwacht Group anticline are presented. Thermodynamic modelling provides the first metamorphic constraints on low-temperature alteration conditions preserved in the Hooggenoeg pillow metabasites. This includes a new quantitative microscale mapping approach that characterizes metamorphic

  14. Sulfur isotope mass-independent fractionation in impact deposits of the 3.2 billion-year-old Mapepe Formation, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    van Zuilen, M. A.; Philippot, P.; Whitehouse, M. J.; Lepland, A.

    2014-10-01

    Theoretical and experimental studies have shown that atmospheric SO2 isotopologue self-shielding effects in the 190-220 nm region of the solar spectrum are the likely cause for mass independent fractionation of sulfur isotopes (S-MIF). The main products of this photochemical reaction - SO3 and S0 - typically define a compositional array of ca. Δ33S/δ34S = 0.06-0.14. This is at odds with the generally observed trend in Archean sulfides, which broadly defines an array of ca. Δ33S/δ34S = 0.9. Various explanations have been proposed, including a diminution of δ34S caused by chemical and biogenic mass-dependent fractionation of sulfur isotopes (S-MDF), mixing with photolytic products produced during felsic volcanic events, or partial blocking of the low-wavelength part of the spectrum due to the presence of reduced atmospheric gases or an organic haze. Early in Earth history large meteorite impacts would have ejected dust and gas clouds into the atmosphere that shielded solar radiation and affected global climate. It is thus likely that at certain time intervals of high meteorite flux the atmosphere was significantly perturbed, having an effect on atmospheric photochemistry and possibly leaving anomalous sulfur isotopic signatures in the rock record. Here we describe the sulfur isotopic signatures in sulfides of spherule beds S2, S3 and S4 of the Barberton Greenstone Belt, South Africa. In particular, in spherule bed S3 - and to a lesser extent S4 - a trend of ca. Δ33S/δ34S = 0.23 is observed that closely follows the expected trend for SO2-photolysis in the 190-220 nm spectral range. This suggests that an impact dust cloud (deposited as spherule beds), which sampled the higher region of the atmosphere, specifically incorporated products of SO2 photolysis in the 190-220 nm range, and blocked photochemical reactions at higher wavelengths (250-330 nm band). By implication, the generally observed Archean trend appears to be the result of mixing of different MIF

  15. Transmission Electron Microscope Study of Platinum Group Element-Rich Micronuggets from Two Spherule Layer Intersections, Barberton Greenstone Belt, South Africa

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    Mohr-Westheide, T.; Greshake, A.; Wirth, R.; Reimold, W. U.; Fritz, J.

    2016-08-01

    New results of a comprehensive transmission electron microscope (TEM) study including microstructural and chemical analyses of three submicrometer sized, primary PGE metal nuggets in Archean spherule layer material from the Barberton Mountain Land.

  16. Implications of a 3.472-3.333 Gyr-old subaerial microbial mat from the Barberton greenstone belt, South Africa for the UV environmental conditions on the early Earth.

    Science.gov (United States)

    Westall, Frances; de Ronde, Cornel E J; Southam, Gordon; Grassineau, Nathalie; Colas, Maggy; Cockell, Charles; Lammer, Helmut

    2006-10-29

    Modelling suggests that the UV radiation environment of the early Earth, with DNA weighted irradiances of about three orders of magnitude greater than those at present, was hostile to life forms at the surface, unless they lived in specific protected habitats. However, we present empirical evidence that challenges this commonly held view. We describe a well-developed microbial mat that formed on the surface of volcanic littoral sediments in an evaporitic environment in a 3.5-3.3Ga-old formation from the Barberton greenstone belt. Using a multiscale, multidisciplinary approach designed to strongly test the biogenicity of potential microbial structures, we show that the mat was constructed under flowing water by 0.25 microm filaments that produced copious quantities of extracellular polymeric substances, representing probably anoxygenic photosynthesizers. Associated with the mat is a small colony of rods-vibroids that probably represent sulphur-reducing bacteria. An embedded suite of evaporite minerals and desiccation cracks in the surface of the mat demonstrates that it was periodically exposed to the air in an evaporitic environment. We conclude that DNA-damaging UV radiation fluxes at the surface of the Earth at this period must either have been low (absorbed by CO2, H2O, a thin organic haze from photo-dissociated CH4, or SO2 from volcanic outgassing; scattered by volcanic, and periodically, meteorite dust, as well as by the upper layers of the microbial mat) and/or that the micro-organisms exhibited efficient gene repair/survival strategies.

  17. Review of tungsten mineralisation in greenstone belts in the eastern and north-eastern Transvaal

    International Nuclear Information System (INIS)

    Tungsten (scheelite) mineralisation is known to occur, occasionally as noteworthy deposits, in the Swazian greenstone belts in the Eastern and North-Eastern Transvaal. An outline and description are given of all known scheelite occurrence in the Sutherland and Murchison Ranges and possibilities of finding such mineralisation in the Barberton greenstone belt are described. Scheelite deposits in these environments: (i) are commonly associated with gold and/or antimony mineralisation; (ii) although found in a variety of host types, commonly occur in amphibolitic and siliceous carbonate rocks; (iii) are found in host rocks belonging to widely separated stratigraphic units in the greenstone belt succession; (iv) display no obviously consistent genetic associations; (v) are typically weakly mineralised. Attention is drawn to the recently postulated theory that tungsten, and spatially related antimony and mercury, mineralisation in the Murchison Range owes its origin to syngenetic processes of concentration, the implications of which, may prove to be important to future investigations. All indications are, however, that the mineralisation is not characterised by any one particular mode of occurrence and that it may not be all of the same age and origin. All known scheelite deposits in the region under review have thus far proved to be of little economic importance

  18. Archaean greenstone belts and associated granitic rocks - A review

    Science.gov (United States)

    Anhaeusser, Carl R.

    2014-12-01

    Archaean greenstone belts and associated granitic rocks comprise some of the most diverse rock types on the Earth's surface and were formed during the early stages of the development of the planet from Eoarchaean to Neoarchaean times - a period extending back from about 4000 to 2500 million years ago. Because of their great age, these rocks have received unprecedented attention from a wide spectrum of Earth scientists striving to learn more about the evolution of the Earth, including its crust, hydrosphere, atmosphere, the commencement of life, and the nature and distribution of mineral deposits. The knowledge gained thus far has accumulated incrementally, beginning with solid field-based studies, the latter being supplemented with increasingly advanced technological developments that have enabled scientists to probe fundamental questions of Earth history. Archaean granite-greenstone terranes display considerable variability of lithologies and geotectonic events, yet there are unifying characteristics that distinguish them from other geological environments. Most greenstone belts consist of a wide variety of volcanic and sedimentary rocks that reflect different evolutionary conditions of formation and all have invariably been influenced by subsequent geotectonic factors, including the intrusion of ultramafic, mafic and granitic complexes, resulting in widespread deformation, metamorphism, metasomatism, as well as mineralization. Geochemical and isotopic age determinations have shown how complex these ancient rocks are and efforts at understanding the nature and evolution of the hydrosphere, atmosphere and primitive life have made Archaean terranes exciting environments in which to study. Conflicting views as to the nature, history and origin of many of the rock types and events in Archaean terranes has been ongoing and stimulating. This review attempts to describe the main lithotypes and other characteristics of granite-greenstone belt geology and points to some

  19. Zircon Lu-Hf systematics: Evidence for the episodic development of Archaean greenstone belts

    Science.gov (United States)

    Smith, P. E.; Tatsumoto, M.; Farquhar, R. M.

    1986-01-01

    A combined U-Th-Pb and Lu-Hf isotopic study of zircons was undertaken in order to determine the provenance and age of an Archean granite-greenstone terrain and to test the detailed application of the Lu-Hf system in various Archean zircons. The eastern Wawa subprovince of the Superior province consists of the low grade Michipicoten and Gamitagama greenstone belts and the granitic terrain. The Hf isotopic data indicate that the typical lithological features of a greenstone belt cycle could be accommodated in a crustal growth model that involved decreasing depth of melting in three isotopically distinct reservoirs: mantle, lower crust and upper crust. The model age of the sources given by the intersection of the lower crustal curve with the bulk earth evolution curve is about 2900 My, in good agreement with the zircon U-Pb basement age. This linear array also has a similar intersection age to that of Proterozoic carbonatite complexes. The general convergence of the other reservoir vectors around this age suggests that mantle depletion, crustal extraction and intracrustal differentiation were all part of the same episodic event. It is also apparent that recycling of older basement was important in the formation of many of the later greenstone belt rocks.

  20. Reworking of atmospheric sulfur in a Paleoarchean hydrothermal system at Londozi, Barberton Greenstone Belt, Swaziland

    NARCIS (Netherlands)

    Roerdink, Desiree L.; Mason, Paul R.D.; Whitehouse, Martin J.; Brouwer, Fraukje M.

    2016-01-01

    Anomalous fractionation of the minor isotopes of sulfur (δ33S, δ36S) in Archean pyrite is thought to reflect photochemical reactions in an anoxic atmosphere, with most samples falling along a reference array with δ36S/δ33S ≈ -1. Small deviations from this array record microbial sulfate reduction or

  1. Geochronology of the Palaeoproterozoic Kautokeino Greenstone Belt, Finnmark, Norway, in its Fennoscandian context

    Science.gov (United States)

    Bingen, Bernard; Solli, Arne; Viola, Giulio; Sverre Sandstad, Jan; Torgersen, Espen; Whitehouse, Martin J.; Skår, Øyvind; Nasuti, Aziz

    2016-04-01

    The northeastern part of the Fennoscandian Shield consists of Archaean cratonic blocks alternating with Palaeoproterozoic greenstone belts ranging in age from c. 2500 to 1950 Ma. Traditionally, the greenstones are interpeted as evidence for rifting of the Archaean continent(s) although it remains unclear whether modern-style oceanic lithosphere developed, followed by a Wilson-cycle-type closure during the Svecokarelian orogeny. Existing geological, isotopic and geochronological data show that the exposed basins hosting the greenstones have distinct lithostratigraphies and geological evolutions and are pericontinental rather than oceanic. A diversity of Palaeoproterozoic mafic mantle derived magmatic rocks show a secular increase of Nd value with time, from EpsilonNd =-2 at 2500 Ma (Shalskiy dikes, Onega, Russia) to EpsilonNd =+4.4 at 2090 Ma (Jouttiaapa basalts, Peräpohja, Finland), suggesting that the regional asthenospheric mantle was less depleted than the model MORB-producing depleted mantle before 2090 Ma. In this work, we report new zircon U-Pb geochronological data in 19 samples from Finnmarkvidda, Norway, to constrain the evolution of the Palaeoproterozoic high-strain Kautokeino Greenstone Belt and its relations with the neighbouring felsic Jergul and Ráiseatnu gneiss complexes. The Jergul complex is an Archaean, low heat flow, TTG cratonic bloc of Karelian affinity formed between 2975 ±10 and 2776 ±6 Ma. The Masi formation, at the base of the Kautokeino Greenstone Belt, is a typical Jatulian quartzite unconformably overlying the Archean basement. An albite-magnetite-rich mafic sill, similar to the Haaskalehto intrusion in Finland, provides a minimum age of 2220 ±7 Ma for the deposition of the quartzite. The Likčá and Čáskejas formations represent the main basaltic volcanism. Direct evidence of an oceanic setting or oceanic suture is lacking. A probably synvolcanic gabbro sill gives an age of 2137 ±5 Ma. Published Sm-Nd whole-rock data on

  2. Geochemistry of Precambrian carbonates: II. Archean greenstone belts and Archean sea water.

    Science.gov (United States)

    Veizer, J; Hoefs, J; Lowe, D R; Thurston, P C

    1989-01-01

    Carbonate rocks with geological attributes of marine sediments are a minor component of the Archean greenstone belts. Despite their relative scarcity, these rocks are important because they record chemical and isotopic properties of coeval oceans. The greenstones containing such carbonates appear to cluster at approximately 2.8 +/- 0.2 and approximately 3.5 +/- 0.1 Ga ago. The samples for the younger group are from the Abitibi, Yellowknife, Wabigoon (Steep Rock Lake), Michipicoten and Uchi greenstone belts of Canada and the "Upper Greenstones" of Zimbabwe. The older group includes the Swaziland Supergroup of South Africa, Warrawoona Group of Australia and the Sargur marbles of India. Mineralogically, the carbonates of the younger greenstones are mostly limestones and of the older ones, ferroan dolomites (ankerites); the latter with some affinities to hydrothermal carbonates. In mineralized areas with iron ores, the carbonate minerals are siderite +/- ankerite, irrespective of the age of the greenstones. Iron-poor dolomites represent a later phase of carbonate generation, related to post-depositional tectonic faulting. The original mineralogy of limestone sequences appears to have been an Sr-rich aragonite. The Archean carbonates yield near-mantle Sr isotopic values, with (87Sr/86Sr)o of 0.7025 +/- 0.0015 and 0.7031 +/- 0.0008 for younger and older greenstones, respectively. The best preserved samples give delta 13C of +1.5 +/- 1.5% PDB, comparable to their Phanerozoic counterparts. In contrast, the best estimate for delta 18O is -7% PDB. Archean limestones, compared to Phanerozoic examples, are enriched in 16O as well as in Mn2+ and Fe2+, and these differences are not a consequence of post-depositional alteration phenomena. The mineralogical and chemical attributes of Archean carbonates (hence sea water) are consistent with the proposition that the composition of the coeval oceans may have been buffered by a pervasive interaction with the "mantle", that is, with

  3. The structural history and mineralization controls of the world-class Geita Hill gold deposit, Geita Greenstone Belt, Tanzania

    Science.gov (United States)

    Sanislav, I. V.; Brayshaw, M.; Kolling, S. L.; Dirks, P. H. G. M.; Cook, Y. A.; Blenkinsop, T. G.

    2016-05-01

    The Geita Hill gold deposit is located in the Archean Geita Greenstone Belt and is one of the largest gold deposits in East Africa. The Geita Greenstone Belt experienced a complex deformation and intrusive history that is well illustrated and preserved in and around the Geita Hill gold deposit. Deformation involved early stages of ductile shearing and folding (D1 to D5), during which episodic emplacement of large diorite intrusive complexes, sills, and dykes occurred. These ductile deformation phases were followed by the development of brittle-ductile shear zones and faults (D6 to D8). The last stages of deformation were accompanied by voluminous felsic magmatism involving the intrusion of felsic porphyry dykes, within the greenstone belt, and the emplacement of large granitic bodies now forming the margins of the greenstone belt. Early, folded lamprophyre dykes, and later lamprophyre dykes, crosscutting the folded sequence are common, although volumetrically insignificant. The gold deposit formed late during the tectonic history of the greenstone belt, post-dating ductile deformation and synchronous with the development of brittle-ductile shear zones that overprinted earlier structural elements. The main mineralizing process involved sulfide replacement of magnetite-rich layers in ironstone and locally the replacement of ferromagnesian phases and magnetite in the diorite intrusions. The intersection between the brittle-ductile (D6) Geita Hill Shear Zone and different structural elements of ductile origin (e.g., fold hinges), and the contact between banded ironstone and folded diorite dykes and sills provided the optimal sites for gold mineralization.

  4. Geochemistry of the Neoarchaean Volcanic Rocks of the Kilimafedha Greenstone Belt, Northeastern Tanzania

    Directory of Open Access Journals (Sweden)

    Charles W. Messo

    2012-01-01

    Full Text Available The Neoarchaean volcanic rocks of the Kilimafedha greenstone belt consist of three petrological types that are closely associated in space and time: the predominant intermediate volcanic rocks with intermediate calc-alkaline to tholeiitic affinities, the volumetrically minor tholeiitic basalts, and rhyolites. The tholeiitic basalts are characterized by slightly depleted LREE to nearly flat REE patterns with no Eu anomalies but have negative anomalies of Nb. The intermediate volcanic rocks exhibit very coherent, fractionated REE patterns, slightly negative to absent Eu anomalies, depletion in Nb, Ta, and Ti in multielement spidergrams, and enrichment of HFSE relative to MORB. Compared to the other two suites, the rhyolites are characterized by low concentrations of TiO2 and overall low abundances of total REE, as well as large negative Ti, Sr, and Eu anomalies. The three suites have a εNd (2.7 Ga values in the range of −0.51 to +5.17. The geochemical features of the tholeiitic basalts are interpreted in terms of derivation from higher degrees of partial melting of a peridotite mantle wedge that has been variably metasomatized by aqueous fluids derived from dehydration of the subducting slab. The rocks showing intermediate affinities are interpreted to have been formed as differentiates of a primary magma formed later by lower degrees of partial melting of a garnet free mantle wedge that was strongly metasomatized by both fluid and melt derived from the subducting oceanic slab. The rhyolites are best interpreted as having been formed by shallow level fractional crystallization of the intermediate volcanic rocks involving plagioclase and Ti-rich phases like ilmenite and magnetite as well as REE-rich phases like apatite, zircon, monazite, and allanite. The close spatial association of the three petrological types in the Kilimafedha greenstone belt is interpreted as reflecting their formation in an evolving late Archaean island arc.

  5. Geotectonic evolution of granitoid-greenstone belts from Crixas, Guarinos, Pilar de Goias - Hidrolina (Goias), Brazil

    International Nuclear Information System (INIS)

    The area in discussion, in a geologic context, constitutes one of the most interesting and complex, within the South American Platform, in Brazilian territory, over which granitoid-greenstone belts are outstanding. The Goiano Complex is the oldest unit in the geologic column herein adopted and composed largely of granitoids, gneiss and migmatites, in the amphibolite facies. Dated samples of the complex have shown two isochrones of Rb/Sr reference, the oldest one is 2.926 +- 65 m.y. and the 87 Sr/86 Sr initial ratio of 0.7001 and the youngest on of 2.471 + 20 m.y. and 87 Sr/86 Sr initial ratio of 0.701. Although the initial ratios data of the Rb/Sr isochron, as well as the parameters in the Pb/Pb analyses may indicate material of mantle source, it may be interpreted, with the help of field data, that the youngest values may indicate the reworking of crustal sialic rocks formed 2.925 +- 65 m.y. ago (oldest isochron), with primitive material contribution. Before such reworking volcanic-sedimentary sequence was deposited over the already formed sialic crust, and it is denominated Pilar de Goias Supergroup which characterizes the Greenstone Belts in the region. The Archean age for the supergroup was evident through the age results of its ultramafic rocks, showing 2.600 m.y. isochron age, with Sm/Nd methods. Besides the geochronology and field studies, basic information for the construction of the geologic column herein presented, there has been done petrographic and litho geochemical studies, both in the Goiano Complex and Pilar de Goias Supergroup, as for the Pilar de Goias Supergroup, the studies were concentrated on its mafic-ultramafic rocks. (author)

  6. Stratigraphy and geochronlogy of the Guarinos greenstone belt, Goiás, Brazil

    Directory of Open Access Journals (Sweden)

    Hardy Jost

    2012-08-01

    Full Text Available The Guarinos greenstone belt is one of the three low metamorphic grade supracrustal rocks assemblage rimmed by orthogneissesof Central Brazil’s Archean Block northern limits. The investigation of the stratigraphy of those greenstone beltsstarted by the end of 1970’s and underwent improvements during the years as a result of detailed geological mapping. Thelatest and accepted stratigraphic model for the Guarinos greenstone belt refers its supracrustal rocks under the GuarinosGroup, which is subdivided into the Serra do Cotovelo (metakomatiites, Serra Azul (metabasalts, São Patricinho (maficmetaturbidites, Aimbé (BIF and Cabaçal (carbonaceous phyllites and impure metarenites formations. Detailed geologicmapping (1:10,000 and drill-cores during an exploration program by Yamana Desenvolvimento Mineral S.A. in the areaallowed a better definition of the metasedimentary package of the Cabaçal Formation, which is here formally proposed tobe subdivided into a Lower Member of carbonaceous phyllites with basalt lava flows and gondite lenses interlayers, anIntermediate Member of gondite, iron formation, metachert and massive barite lenses, and an Upper Member of carbonaceous phyllites with minor metachert lenses. The impure metarenites, formerly considered as part of the Cabaçal Formation, are proposedunder the Mata Preta Formation, which is laterally interfingered with the Cabaçal Formation. U-Pb LA-ICP-MS geochronologicaldata of detrital zircon grains from the São Patricinho mafic metaturbidites and the impure metarenites of the Mata Preta formationsindicate that the major source-area of the clastic load had a Siderian to Rhyacian age, with minor contribution from Archean rocks.From the rock assemblage of both units and their contact relationships it is concluded that the basin stage they represent evolved duringthe world-wide Anoxic Oceanic Event (AOE that took place during the 2.2 to 2.06 Ga, represented by the carbonaceous phyllites ofthe

  7. An overview of the lithological and geochemical characteristics of the Mesoarchean (ca. 3075) Ivisaartoq greenstone belt, southern West Greenland

    DEFF Research Database (Denmark)

    Polat, A.; Frei, Robert; Appel, P.W.U.;

    2008-01-01

    -silicate metasomatism, between 3075 and 2961 Ma. The trace element systematics of the least altered rocks are consistent with a subduction zone geodynamic setting. On the basis of lithological similarities between the Ivisaartoq greenstone belt and Phanerozoic forearc/backarc ophiolites, and intra-oceanic island arcs......, we suggest that the Ivisaartoq greenstone belt represents a relic of dismembered Mesoarchean suprasubduction zone oceanic crust. The Sm-Nd isotope system appears to have remained relatively undisturbed in picrites, tholeiitic pillow lavas, gabbros, and diorites. As a group, picrites have more...... depleted initial Nd isotopic signatures ( Nd = +4.2 to +5.0) than gabbros, diorites, and tholeiitic basalts ( Nd = +0.3 to +3.1), consistent with a strongly depleted mantle source. In some areas gabbros include up to 15 cm long white inclusions (xenoliths). These inclusions are composed primarily (>90...

  8. Drilling for the Archean Roots of Life and Tectonic Earth in the Barberton Mountains

    Directory of Open Access Journals (Sweden)

    Nicola McLoughlin

    2009-09-01

    Full Text Available In the Barberton Scientific Drilling Program (BSDP we successfully completed three drill holes in 2008 across strategically selected rock formations in the early Archean Barberton Greenstone Belt, South Africa. This collaborative project’s goal is to advance understanding of geodynamic and biogeochemical processes of the young Earth. The program aims to better define and characterize Earth’s earliest preserved ocean crust shear zones and microbial borings in Archean basaltic glass, and to identify biogeochemical fingerprints of ancient ecological niches recorded in rocks. The state-of-the-art analytical and imaging work will address the question of earliest plate tectonics in the Archean, the δ18O composition, the redox state and temperature of Archean seawater, and the origin of life question.

  9. Archaean hydrothermal zircon in the Abitibi greenstone belt: Constraints on the timing of gold mineralisation

    International Nuclear Information System (INIS)

    Hydrothermal zircons have been found in Archaean mesothermal Au-veins and altered wallrock selvages at Val d'Or, in the Abitibi greenstone belt of Canada. The zircons are paragenetically associated with vein quartz, tourmaline, mica, carbonate, scheelite, pyrite, and gold. Zirconium mobility, and the consequent occurrence of hydrothermal zircon, may be associated with the intense tourmalinisation characteristic of Archaean gold deposits in this district. The SHRIMP ion-microprobe has been used to analyse hydrothermal zircons from four separate mines spatially associated with the Bourlamaque batholith, and has yieleded ages constraining formation of the Au-bearing vein systems to within 20 Ma of emplacement of the pluton. The ion microprobe data reveal multiple stages of hydrothermal zircon growth in the vein systems, contemporaneous with the regional metamorphic peak and late kinematic activity along regional structures. Younger (including Proterozoic) ages previously obtained for the veins, using other minerals and isotopic schemes, must reflect either alteration or renewed mineral growth during much later reactivation of fluids along the same structures up to 400 Ma after initial formation of the veins. (orig.)

  10. Ophiolitic Chromitites from the Andriamena Greenstone Belt, Madagascar: Possible Evidence for mid-Archean Plate Tectonics

    Science.gov (United States)

    Reisberg, L. C.; Ohnenstetter, M.; Zimmermann, C.; Ratefiarimino, A.; Levy, D.

    2015-12-01

    Determining the time of the onset of plate tectonics is critical to understanding the geodynamic processes that controlled the evolution of the early Earth. The near absence of Archean ophiolites, as defined by the presence of a residual ultramafic section, has been considered to be one of the primary arguments against Archean plate tectonics. The Andriamena greenstone belt of Madagascar contains massive chromitite bodies consisting of about 90% chromite and about 10% gangue minerals, mostly secondary (talc, green amphibole, orthopyroxene, Ca and Mg carbonate). Numerous observations argue in favor of an ophiolitic origin for these chromitites, including the high Cr# (0.67-0.74), coupled with relatively high Mg# (0.6-0.78) of the constituent chromite. In addition, these phases display extremely low TiO2 contents (clustered, with 187Os/188Os ranging from 0.1057 to 0.1059, corresponding to TRD model ages of ~ 3.2 Ga, assuming primitive upper mantle parameters. 186Os/188Os measurements are in progress. If the ophiolitic nature of the chromitites is confirmed, our results might imply that geodynamic mechanisms similar to present-day plate tectonic processes may already have been active in the mid-Archean Earth.

  11. Some Speculations Concerning The Abitibi Greenstone Belt As A Possible Analog To The Early Martian Crust

    Science.gov (United States)

    Russell, M.; Allwood, A.; Anderson, R. B.; Atkinson, B.; Beaty, D.; Bristow, T. F.; Ehlmann, B. L.; Grotzinger, J. P.; Hand, K. P.; Halevy, I.; Hurowitz, J. A.; Knoll, A.; McCleese, D. J.; Milliken, R.; Stolper, D. A.; Stolper, E. M.; Tosca, N. J.; Agouron Mars Simulation Field Team

    2011-12-01

    The Noachian crust of Mars comprises basaltic and, potentially, komatiitic lavas derived from a hot mantle slightly more reducing and sulfur-rich than that of the Earth. Ultramafic volcanic sequences of the ~2.7Ga Tisdale Group of the Abitibi Greenstone Belt, Ontario, provide a potential analog to these early martian lavas. The Abitibi rocks are a possible source of quartz veins carrying, in places, pyrite, carbonate and gold. These were hydrothermally introduced into volcanic and sedimentary rocks during greenschist metamorphism. Kilometer-scale talc-magnesite zones, resulting from the carbonation of serpentinized ultramafics, may have been the source and seawater, with some magmatic addition, was probably responsible for the pervasive alteration, although the chemical nature of hydrothermal fluids circulating in such piles depends upon the temperature of wall-rock interactions and is largely independent of fluid origin. Any sulfides and gold in unaltered ultramafic putative source rocks may have been lost to the invasive convective fluids. Given high heat flow and the presence of a hydrosphere, hydrothermal convection cells were probably the main mechanism of heat transfer through the crust on both planets. Exploration of the Abitibi belt provides a template for possible martian exploration strategies. Orbital remote sensing indicates that some ultramafic rocks on Mars have also been serpentinized and isolated areas of magnesite have been recently discovered, overlying altered mafic crust, with characteristic ridges at scales of a few hundred meters. While cogent arguments have been made favoring sedimentary exhalative accumulations of hydrothermal silica of the kind that are known to harbor bacteria on our own planet, no in situ siliceous sinters or even quartz veins have been identified with certainty on Mars. Here, we report on the mineralogic and visible to infrared spectral characteristics of mafic and ultramafic lithologies at Abitibi for comparison to

  12. Multistage gold mineralization in the Wa-Lawra greenstone belt, NW Ghana: The Bepkong deposit

    Science.gov (United States)

    Amponsah, Prince Ofori; Salvi, Stefano; Didier, Béziat; Baratoux, Lenka; Siebenaller, Luc; Jessell, Mark; Nude, Prosper Mackenzie; Gyawu, Eugene Adubofour

    2016-08-01

    The Bepkong gold deposit is one of several gold camps in the Paleoproterozoic Wa-Lawra greenstone belt in northwest Ghana. These deposits lay along the Kunche-Atikpi shear zone, which is part of the larger transcurrent Jirapa shear zone. The formation of these shear zones can be attributed to the general ESE-WNW major shortening that took place in the Wa-Lawra belt. Gold mineralization in the Bepkong deposit mainly occurs within graphitic shales and volcaniclastic rocks. The ore consists of four N-S trending lenticular bodies, plunging steeply to the south, that are lithologically and structurally controlled. Their shape and thickness are variable, though a general strike length of 560 m and an overall thickness of 300 m can be defined. An alteration mineral assemblage characterises the ore, and consists of chlorite-calcite-sericite-quartz-arsenopyrite-pyrite. Pyrite, as distinct from arsenopyrite, is not limited to the altered rocks and occurs throughout the area. At Bepkong, gold is associated with arsenopyrite and pyrite, which occur disseminated in the mineralized wall rock, flanking Type-1 quartz veins, or within fractures crossing these veins. Textural observations indicate the early formation of abundant arsenopyrite, followed by pyrite, with chalcopyrite, galena, sphalerite and pyrrhotite occurring as inclusions within pyrite and altered arsenopyrite. Detailed petrography, coupled with SEM, LA-ICP-MS and EMP analyses, indicate that gold in the Bepkong deposit occurs in three distinct forms: (i) invisible gold, mostly in arsenopyrite (ii); visible gold as micron-size grains within fractures and altered rims of arsenopyrite, as well as at the interface of sulphide grains; (iii) free visible gold in fractures in quartz veins and their selvages. We interpret the invisible gold to have co-precipitated with the early-formed arsenopyrite. The small visible gold grains observed within the sulphide interfaces, altered arsenopyrite, fractures and grain boundaries

  13. Physical volcanology of the mafic segment of the subaqueous New Senator caldera, Abitibi greenstone belt, Quebec, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Lyndsay N; Mueller, Wulf U [Universite du Quebec a Chicoutimi, 555 boul. du l' Universite, Chicoutimi, Quebec, G7H2B1 (Canada)], E-mail: lyndsay.moore@uqac.ca

    2008-10-01

    Archean calderas provide valuable insight into internal geometries of subaqueous calderas. The New Senator caldera, Abitibi greenstone belt, Canada, is an Archean example of a subaqueous nested caldera with a basal stratigraphy dominated by gabbro-diorite dykes and sills, ponded magmas and basalt and andesite lava flows. The aim of our study is to focus on the use of physical volcanology to differentiate between the various mafic units found at the base of the New Senator caldera. Differentiation between these various mafic units is important from an exploration point of view because in modern subaqueous summit calders (e.g. Axial Seamount) margins of ponded magmas are often sites of VMS formation.

  14. Evidence for spreading in the lower Kam Group of the Yellowknife greenstone belt: Implications for Archaean basin evolution in the Slave Province

    Science.gov (United States)

    Helmstaedt, H.; Padgham, W. A.

    The Yellowknife greenstone belt is the western margin of an Archean turbidite-filled basin bordered on the east by the Cameron River and Beaulieu River volcanic belts (Henderson, 1981; Lambert, 1982). This model implies that rifting was entirely ensialic and did not proceed beyond the graben stage. Volcanism is assumed to have been restricted to the boundary faults, and the basin was floored by a downfaulted granitic basement. On the other hand, the enormous thickness of submarine volcanic rocks and the presence of a spreading complex at the base of the Kam Group suggest that volcanic rocks were much more widespread than indicated by their present distribution. Rather than resembling volcanic sequences in intracratonic graben structures, the Kam Group and its tectonic setting within the Yellowknife greenstone belt have greater affinities to the Rocas Verdes of southern Chile, Mesozoic ophiolites, that were formed in an arc-related marginal basin setting. The similarities of these ophiolites with some Archean volcanic sequences was previously recognized, and served as basis for their marginal-basin model of greenstone belts. The discovery of a multiple and sheeted dike complex in the Kam Group confirms that features typical of Phanerozoic ophiolites are indeed preserved in some greenstone belts and provides further field evidence in support of such a model.

  15. The Fazenda Gavião granodiorite and associated potassic plutons as evidence for Palaeoproterozoic arc-continent collision in the Rio Itapicuru greenstone belt, Brazil

    Science.gov (United States)

    Costa, Felipe G.; Oliveira, Elson P.; McNaughton, Neal J.

    2011-08-01

    Several granitic plutons have intruded the Palaeoproterozoic Rio Itapicuru greenstone belt, São Francisco craton, Brazil, in the time interval 2163-2080 Ma, but their tectonic significance is poorly understood. The Fazenda Gavião granodiorite (FGG) is one of a set of plutons emplaced along the western boundary of the greenstone belt with Archaean migmatite-gneiss basement. The pluton is mostly composed of hornblende granodiorite, occasionally crosscut by syn-plutonic mafic dykes. The FGG is metaluminous, medium- to high-K calc-alkaline with relatively constant silica abundances (SiO2 ˜ 63-66 wt%), high Sr (900-800 ppm) and high Ba (1000-1500 ppm). The associated mafic dykes are ultrapotassic, with high abundances of Ba, Sr, MgO, Ni, Cr, and light rare earth elements, suggesting derivation from partial melts of an enriched mantle source. The FGG originated probably by fractional crystallization from a primitive K-rich mafic magma that interacted with crustal melts. Its zircon U-Pb SHRIMP age of 2106 ± 6 Ma indicates that the FGG is younger than the early (2163-2127 Ma) tonalite-trondhjemite-granodiorite (TTG) and calc-alkaline arc plutons of the greenstone belt, and is closely related in time and space with potassic to ultrapotassic plutons (ca. 2110-2105 Ma). The negative ɛNd(t) of FGG and coeval K-rich plutons of the Rio Itapicuru greenstone belt contrasts markedly with the positive ɛNd(t) of the older arc plutons, indicating a major change of isotope signatures in granites of the Rio Itapicuru greenstone belt with time. This isotope shift may be related to magma contamination with older continental material and/or derivation of the parental potassic magma from enriched lithospheric mantle sources. We suggest that the K-rich plutons were emplaced during or shortly after Palaeoproterozoic arc-continent collision.

  16. Source heterogeneity for the major components of ~3.7 Ga banded iron formations (Isua Greenstone Belt, Western Greenland)

    DEFF Research Database (Denmark)

    Frei, Robert; Polat, Ali

    2006-01-01

    of the depositional environment and to the understanding of depositional mechanisms of these earliest chemical sediments. Rare earth element (REE)-yttrium (Y) patterns of the individual mesobands show features of modern seawater with diagnostic cerium (Ce/Ce ), presodymium (Pr/Pr ) and Y/holmium (Ho) anomalies. Very......We report trace element, samarium (Sm)-neodymium (Nd) and lead (Pb) isotopic data for individual micro-and mesobands of the Earth's oldest Banded Iron Formation (BIF) from the  3.7-3.8 Ga Isua Greenstone Belt (IGB, West Greenland) in an attempt to contribute to the characterization...... low high field strength elements (HFSE) concentrations indicate essentially detritus-free precipitation. Uranogenic Pb isotope data define a correlation line with a slope of 3691 ± 41 Ma, indicating that the uranium (U)-lead (Pb) system remained closed after the formation of this BIF. High 207Pb/204Pb...

  17. Potential of thermal emissivity for mapping of greenstone rocks and associated granitoids of Hutti Maski Schist belt, Karnataka

    Science.gov (United States)

    Guha, A.; Vinod Kumar, K.

    2014-11-01

    In the present study, different temperature-emissivity separation algorithms were used to derive emissivity images based on processing of ASTER( Advanced spaceborne thermal emission and reflection radiometer) thermal bands. These emissivity images have been compared with each other in terms of geological information for mapping of major rock types in Hutti Maski schist Belt and its associated granitoids. Thermal emissivity images are analyzed conjugately with thermal radiance image, radiant temperature image and albedo image of ASTER bands to understand the potential of thermal emissivity in delineating different rock types of Archaean Greenstone belt. The emissivity images derived using different emissivity extraction algorithms are characterised with poor data dimensionality and signal to noise ratio. Therefore, Inverse MNF false-colour composites(FCC) are derived using bands having better signal to noise(SNR)ratio to enhance the contrast in emissivity. It has been observed that inverse-MNF of emissivity image; which is derived using emissivity-normalisation method is suitable for delineating silica variations in granite and granodioritic gneiss in comparison to other inverse- MNF-emissivity composites derived using other emissivity extraction algorithms(reference channel and alpha residual method). Based on the analysis of ASTER derived emissivity spectra of each rocks, band ratios are derived(band 14/12,band 10/12) and these ratios are used to delineate the rock types based on index based FCC image. This FCC image can be used to delineate granitoids with different silica content. The geological information derived based on processing of ASTER thermal images are further compared with the image analysis products derived using ASTER visible-near-infrared(VNIR) and shortwave infrared(SWIR) bands. It has been observed that delineation of different mafic rocks or greenstone rocks(i.e. separation between chlorite schist and metabasalt) are better in SWIR composites

  18. Geochemistry and petrogenesis of intrusions at the Golden Pride gold deposit in the Nzega greenstone belt, Tanzania

    Science.gov (United States)

    Kwelwa, Shimba; Manya, Shukrani; Vos, Ivo M. A.

    2013-10-01

    The greenstone sequence at Golden Pride gold deposit in Nzega greenstone belt of northern Tanzania is cross-cut by several intrusions whose geochemistry and petrogenesis is unknown. We present major and trace elements geochemistry of the Golden Pride igneous intrusions with the aim of constraining their petrogenesis and their ancient tectonic setting. The Golden Pride intrusions are geochemically categorized into two main rock suites: the granodiorites (which include the porphyries) and the lamprophyres (formerly intermediate intrusions). The granodiorites are characterized by SiO2 contents of 54.5-69.9 wt%, elevated MgO (1.22-3.59 wt%) Cr (up to 54 ppm), Mg# (35-55) pointing to a mantle component in the source. Compared to the TTG and adakites, the granodiorites are characterized by higher K2O (1.52-4.30 wt%), medium HREE (Gd/ErCN = 2.13-3.77) and marked enrichment in Ba and Sr (Ba + Sr = 819-2922 ppm) and are in these respects similar to Archean high Ba-Sr sanukitoids. The rocks in this suite are interpreted to have formed by partial melting of an enriched mantle wedge through two metasomatic events: subduction-related fluids/melts and by metasomatism related to asthenospheric mantle upwelling caused by slab break-off. Compared to the granodiorites, the lamprophyres have higher MgO contents (2.37-3.81 wt%), Cr (60-298 ppm), Co (31-57 ppm) and Mg# (32-40). They also show slight enrichment of the LREE relative to HREE (La/YbCN = 3.3-7.1), moderate Nb-Ti depletion and sub-chondritic Zr/Hf ratios (34-41). These geochemical features are attributed to derivation of the Golden Pride lamprophyres by partial melting of the amphibole-rich metasomatized mantle by slab derived hydrous fluids. Both of the Golden Pride intrusion suites show strong affinity to subduction related magmas and we interpret that the entire greenstone sequence and the associated intrusions at Golden Pride gold deposit formed in a late Archaean convergent margin.

  19. The discovery of the Neoarchean mafic dyke swarm in Hengshan and reinterpretation of the previous "Wutai greenstone belt"

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The structural mapping and section study indicate that the "greenstone belts" in the southern to central parts of Hengshan were intensively sheared and transposed mafic dyke swarm,which originally intruded into the Neoarchean grey gneiss and high-pressure granulite terrain(HPGT).The HPGT is characterized by flat-dipping structures,to the south it became steep and was cut by the Dianmen mafic dyke swarm.After high-pressure granulite-facies metamorphic event,the mafic dyke swarm occurred,and was associated with the extensional setting and reworked by the late strike-slip shearing.The zircon age dating proves that the Dianmen mafic dyke swarm was emplaced during the period between 2499±4 Ma and 2512±3 Ma,followed by late tectonothermal reworking.The Dianmen mafic dyke swarm further documents the extensional episode in the central to northern parts of North China Craton(NCC),providing the important constraint for the limit between Archean and Proterozoic and correlation between NCC and other cratonic blocks of the world.

  20. Geochemistry of metavolcanic rocks in the Archean Greenstone Belt of Identidade, SE Para, Brazil

    International Nuclear Information System (INIS)

    The paper discusses the geochemistry of the ultramafic and mafic volcanic rocks of the Identidade belt (IDB), in order to present hypothesis about their possible sources and magmatic evolution. The chemical data were obtained by ICP method. The analytical errors are less then 5% for major elements, less than 10% for the minor ones, and around 5% for trace elements. Save additional data from the meta ultramafic rocks of the Seringa belt, situated 100 km to the west of the IDB, were also considered. The XLFRAC program was employed for fractional crystallization modelling of major elements. For trace element modelling the equations of fractional crystallization and equilibrium partial melting were applied, using an unpublished program written in Pascal. 10 figs. 8 tabs

  1. A Detailed Record of Archean Biogochemical Cycles and Seawater Chemistry Preserved in Black Shales of the Abitibi Greenstone Belt

    Science.gov (United States)

    Scott, C.; Planavsky, N. J.; Bates, S. M.; Wing, B. A.; Lyons, T. W.

    2011-12-01

    Geological and biological evolution are intimately linked within the Earth System through the medium of seawater. Thus, in order to track the co-evolution of Life and Earth during the Archean Eon we must determine how biogeochemical cycles responded to and initiated changes in the composition of Archean seawater. Among our best records of biogeochemical cycles and seawater chemistry are organic carbon-rich black shales. Here we present a detailed multi-proxy study of 2.7 Ga black shales from the Abitibi Greenstone Belt, Canada. Abitibi shales demonstrate extreme enrichments in total organic carbon (up to 15 wt. %) and total sulfur (up to 6 wt. %) reflecting vigorous biogeochemical cycling in the basin, likely driven by cyanobacteria. The speciation of reactive Fe minerals indicates that pyrite formed in a sulfidic water column (euxinia) and that dissolved Fe was the limiting reactant. The deposition of more than 50 m of euxinic black shales suggests that the Fe-rich conditions reflected by Archean BIF deposition were not necessarily ubiquitous. Biologically significant trace metals fall into two categories. Metals that can be delivered to seawater in large quantities from hydrothermal sources (e.g., Cu and Zn) are enriched in the shales, reflecting their relative abundance in seawater. Conversely, metals that are primarily delivered to the ocean during oxidative weathering of the continents (e. g., Mo and V) are largely absent from the shales, reflecting depleted seawater inventories. Thus, trace metal supply at 2.7 Ga was still dominated by geological processes. Biological forcing of trace metal inventories, through oxidative weathering of the continents, was not initiated until 2.5 Ga, when Mo enrichments are first observed in the Mt. McRae Shale, Hamersley Basin. Multiple sulfur isotope analysis (32S, 33S, 34S) of disseminated pyrite displays large mass independent fractionations (Δ33S up to 6 %) reflecting a sulfur cycle dominated by atmospheric processes

  2. Age constraints on felsic intrusions, metamorphism and gold mineralisation in the Palaeoproterozoic Rio Itapicuru greenstone belt, NE Bahia State, Brazil

    Science.gov (United States)

    Mello, E.F.; Xavier, R.P.; McNaughton, N.J.; Hagemann, S.G.; Fletcher, I.; Snee, L.

    2006-01-01

    U-Pb sensitive high resolution ion microprobe mass spectrometer (SHRIMP) ages of zircon, monazite and xenotime crystals from felsic intrusive rocks from the Rio Itapicuru greenstone belt show two development stages between 2,152 and 2,130 Ma, and between 2,130 and 2,080 Ma. The older intrusions yielded ages of 2,152??6 Ma in monazite crystals and 2,155??9 Ma in zircon crystals derived from the Trilhado granodiorite, and ages of 2,130??7 Ma and 2,128??8 Ma in zircon crystals derived from the Teofila??ndia tonalite. The emplacement age of the syntectonic Ambro??sio dome as indicated by a 2,080??2-Ma xenotime age for a granite dyke probably marks the end of the felsic magmatism. This age shows good agreement with the Ar-Ar plateau age of 2,080??5 Ma obtained in hornblendes from an amphibolite and with a U-Pb SHRIMP age of 2,076??10 Ma in detrital zircon crystals from a quartzite, interpreted as the age of the peak of the metamorphism. The predominance of inherited zircons in the syntectonic Ambro??sio dome suggests that the basement of the supracrustal rocks was composed of Archaean continental crust with components of 2,937??16, 3,111??13 and 3,162??13 Ma. Ar-Ar plateau ages of 2,050??4 Ma and 2,054??2 Ma on hydrothermal muscovite samples from the Fazenda Brasileiro gold deposit are interpreted as minimum ages for gold mineralisation and close to the true age of gold deposition. The Ar-Ar data indicate that the mineralisation must have occurred less than 30 million years after the peak of the metamorphism, or episodically between 2,080 Ma and 2,050 Ma, during uplift and exhumation of the orogen. ?? Springer-Verlag 2006.

  3. Structural and geochemical mapping of a Fe-mineralized quartz-mica rich unit in the Ringvassøya Greenstone Belt, West Troms Basement Complex

    OpenAIRE

    Elvenes, Hallgeir

    2015-01-01

    Ringvassøy is one of a chain of large coastal islands representing the Archaean to Paleoproterozoic West Troms Basement Complex (WTBC), west of the Caledonides. On Ringvassøy, a basement of mainly tonalitic gneiss is overlain by the Ringvassøy Greenstone Belt (RGB), which is metamorphosed up to middle amphibolite facies. Tonalitic gneiss in the west and southeast of the island has U–Pb zircon ages of 2.84–2.82 Ga, similar to U–Pb zircon ages of 2.85–2.83 Ga for metavolcanics in the RGB. Mafic...

  4. Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil

    Science.gov (United States)

    Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca

    2016-03-01

    Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt

  5. Structural, Petrographic and Geochemical Characteristics of Mafic Dikes Intrusive in Metasedimentary Rocks of the Crixás Greenstone Belt, Goiás

    Directory of Open Access Journals (Sweden)

    Hardy Jost

    2010-10-01

    Full Text Available Mafic dikes and stocks are a common feature in the Archean terrain of Goiás, Central Brazil, where they occur asswarms of 2.3 - 2.5 Ga within the granite-gneiss complexes (2.8 e 2.7 Ga, as well as intrusions related to the komatiite andbasalt flows of the greenstone belts lower stratigraphic units, but were unknown within the upper metasedimentary units.Detailed study of core sections from several drill-sites in the area of the Crixás greenstone belt gold deposits showed thatdike intrusion occurred after the main Paleoproterozoic deformation and metamorphism of the metasedimentary units,and literature data indicate that the magmatic zircons from the dikes yielded an age of 2,170 ± 17 Ma. Petrographic andgeochemical data show that they have the composition of epicratonic high-Ti diabases, which are similar to the largecontinental flood basalts of the Paraná Basin. The age of the intrusions may be correlated with the short time-interval of theRhyacian (2.20 to 2.17 Ga, during which successive localized episodes of mantle plume volcanism occurred on the Earth.

  6. U-Pb SHRIMP ages of detrital zircons from Hiriyur formation in Chitradurga Greenstone belt and its implication to the Neoarchean evolution of Dharwar craton, South India

    International Nuclear Information System (INIS)

    We report newly obtained U-Pb SHRIMP ages of detrital zircons from metagreywackes in the Hiriyur Formation (Chitradurga Group, Dharwar Supergroup) from the central eastern part of the Chitradurga greenstone belt. U-Pb analyses yield three major Neoarchean age populations ranging from 2.70 - 2.54 Ga with some minor age population of Mesoarchean. The maximum age of deposition is constrained by the youngest detrital zircon population at 2546 Ma. This is the first report of the occurrence of supracrustal rocks less than 2.58 Ga in the central part of Chitradurga greenstone belt. Close evaluation of detrital ages with the published ages of surrounding igneous rocks suggest that the youngest detrital zircons might be derived from rocks of the Eastern Dharwar craton and the inferred docking of the western and eastern Dharwar cratons happened prior to the deposition of the Hiriyur Formation. The Chitradurga shear zone, dividing the Dharwar craton into western and eastern blocks, probably developed after the deposition. Furthermore, the lower intercept is interpreted as evidence for the Pan-African overprints in the study area. (author)

  7. Palaeomagnetism of Archaean rocks of the Onverwacht Group, Barberton Greenstone Belt (southern Africa): Evidence for a stable and potentially reversing geomagnetic field at ca. 3.5 Ga

    NARCIS (Netherlands)

    Biggin, A.J.; Wit, M.J. de; Langereis, C.G.; Zegers, T.E.; Voute, S.; Dekkers, M.J.; Drost, K.

    2011-01-01

    Palaeomagnetic data from the Palaeoarchaean Era (3.2–3.6 Ga) have the potential to provide us with a great deal of information about early conditions within, and processes affecting, the Earth's core, mantle, and surface environment. Here we present new data obtained from some of the oldest palaeoma

  8. Mineralogical and geochemical characteristics of zircon from diorite porphyry dyke in Sergozerskoe gold occurrence (the Strel'ninsky greenstone belt, Kola region

    Directory of Open Access Journals (Sweden)

    Kudryashov N. M.

    2016-03-01

    Full Text Available Mineralogical and geochemical investigation of zircon from diorite porphyry from Sergozerskoe occurrence has been carried out. Study of morphology and inner structure of zircon crystals in back scattered electron rays as well as assaying for content and distribution of Rare Earth Elements in mineral grains have given important information about conditions of crystallization and following metasomatic alteration of zircon. Zircon characteristics show that it crystallized in a melt, enriched in fluid phase. Fluid influence lasted after zircon crystallization, this reflected in uneven composition of the mineral and in configuration of REE spectra, typical for metasomatic zircon. Similar zircon characteristics have been noted in zircons from other gold occurrences in greenstone belts in the Kola region

  9. Deep Metamorphic Rock Series of Bayan Wula-mountain Granite-greenstone Belt and Gold MineralizationMA Runze%巴彦乌拉山深变质岩系的花岗-绿岩带与金成矿

    Institute of Scientific and Technical Information of China (English)

    胡晰; 马润则; 陈志耕; 张腊梅; 陈娟; 刘颖倩

    2015-01-01

    A large area of Archean granite - greenstone belt exposed in Bayan wula-mountain, which bedrock outcrops good. Survey area′greenstone belt is existing as the green schist facies of tectonic schist. At present, domestic and foreign atta-ches great importance to the study of granite greenstone belt, The major reason is that research on it has mineral and geological sig-nificance. However, Gold directly affecting the financial securi-ty of the country as a precious metal, which is very important for the national economy stability. Granite - greenstone belt has a close relation with gold deposit. At present, China 's most im-portant gold producing type is greenstone type gold deposit.%巴彦乌拉山出露大面积的太古代花岗-绿岩带,基岩出露良好。本区的绿岩带是以变质程度为绿片相的构造片岩形式出现的。国内外对花岗绿岩带的研究非常重视,主要是因为其研究对矿产和地质都具有重大意义。然而金为直接影响国家金融安全的贵重金属,对于国家的经济稳定有极其重要的作用。其中花岗-绿岩带与金成矿有着密切关系。目前我国主要的产金类型为绿岩型金矿。

  10. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: marcio@unb.br; Armstrong, Richard [Australian National Univ., Canberra, ACT (Australia). Research School of Earth Sciences; Resende, Marcelo Goncalves [Universidade Catolica de Brasilia, DF (Brazil). Curso de Graduacao em Engenharia Ambiental

    2000-03-01

    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 {+-} 12 Ma) magmatic event. Sm-Nd isotopic data (initial e{sub CHUR} values between -10.5 and -14.9) and T{sub DM} values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  11. Field and geochemical characterisitics of the Mesoarchean (~3075 ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in a supra-subduction oceanic crust

    DEFF Research Database (Denmark)

    Polat, A.; Appel, P.W.U.; Frei, Robert;

    2006-01-01

    The Mesoarchean (ca. 3075 Ma) Ivisaartoq greenstone belt in southern West Greenland includes variably deformed and metamorphosed pillow basalts, ultramafic flows (picrites), serpentinized ultramafic rocks, gabbros, sulphide-rich siliceous layers, and minor siliciclastic sedimentary rocks. Primary....... The belt underwent at least two stages of calc-silicate metasomatic alteration and polyphase deformation between 2963 and 3075 Ma. The stage I metasomatic assemblage is composed predominantly of epidote (now mostly diopside) + quartz + plagioclase ± hornblende ± scapolite, and occurs mainly in pillow cores...... + garnet + amphibole + plagioclase + quartz ± vesuvianite ± scapolite ± epidote ± titanite ± calcite ± scheelite. Given that the second stage of metasomatism is closely associated with shear zones and replaced rocks with an early metamorphic fabric, its origin is attributed to regional dynamothermal metamorphism. The least altered pillow basalts, picrites, gabbros, and diorites are characterized by LREE...

  12. Brazil's premier gold province. Part II: geology and genesis of gold deposits in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero

    Science.gov (United States)

    Lobato, Lydia; Ribeiro-Rodrigues, Luiz; Vieira, Frederico

    2001-07-01

    Orogenic, gold deposits are hosted by rocks of the Archean Rio das Velhas greenstone belt in the Quadrilátero Ferrífero region, Minas Gerais state, Brazil, one of the major gold provinces in the world. The gold deposits occur at the base of the mafic-ultramafic succession, with the most important orebodies controlled by E-W-striking, strike-slip faults. The main mineralization styles are (1) structurally controlled, sulfide replacement zones in banded iron formation (BIF); (2) disseminated sulfide minerals and gold in hydrothermally altered rocks along shear zones; and (3) auriferous quartz-carbonate-sulfide veins and veinlets in mafic, ultramafic, and felsic volcanic rocks, and also in clastic sedimentary rocks. The most common host rocks for ore are metamorphosed oxide- and carbonate-facies banded iron (± iron-rich metachert) formations (e.g., the Cuiabá, São Bento and Raposos deposits) and the lapa seca unit, which is a local term for intensely carbonatized rock (e.g., the giant Morro Velho mine with >450 t of contained gold). Metabasalts host most of the remaining gold deposits. Mineralogical characteristics and fluid inclusion studies suggest variations in the H2O/CO2 ratio of a low-salinity, near-neutral, reducing, sulfur-bearing, ore fluid. The presence of abundant CH4-rich inclusions is related to reduction of the original H2O-CO2 fluid via interaction with carbonaceous matter in the wallrocks. Oxygen fugacity was close to that of graphite saturation, with variations likely to have been influenced by reaction with the carbonaceous matter. Carbon-rich phyllites and schists, which commonly bound ore-bearing horizons, seem to have played both a physical and chemical role in localizing hydrothermal mineral deposition. Microtextural studies indicate that gold deposition was mainly related to desulfidation reactions, and was paragenetically coeval with precipitation of arsenic-rich iron sulfide minerals. Carbon isotope data are compatible with dissolution of

  13. Paleoproterozoic Greenstone-Granite Belts in Northern Brazil and the Former Guyana Shield - West African Craton Province

    Directory of Open Access Journals (Sweden)

    Ian McReath

    2006-03-01

    Full Text Available The mainly meta-volcano-sedimentary Vila Nova Group and associated granites constitute separate belts, which formpart of a large paleoproterozoic (mainly rhyacian province in the Guyana Shield of which northern Brazil forms a part, andthe West African Craton. In Brazil the southwestern Serra do Ipitinga and Serra Tumucumaque-Serra do Navio belts have noobvious geometrical extensions in the Guyanas or Venezuela, and may represent deposits formed at penecontemporaneouspassive continental margins and ocean floor spreading centres. To the Northeast the Serra Lombarda-Tartarugalzinho andOiapoque belts are continuations of Guianese belts. In the former the igneous rocks have geochemical characteristics ofsuprasubduction environments. Belts in the Guyana Shield and West African Craton have many similar features. Themegaprovince evolved in a number of stages, which may have started at about 2.3 Ga, and continued with diminished activityafter 2.11 Ga. Both major juvenile additions and (possibly minor reworking of earlier crust contributed to the growth of theprovince. The major transcurrent deformation, responsible for the present structure of the belts, probably occurred duringthe later stages of evolution of the province, but metamorphism and deformation are registered even in the oldest rocks.

  14. Rochas ultramáficas plutônicas do greenstone belt Rio das Velhas na porção central do Quadrilátero Ferrífero, Minas Gerais, Brasil Plutonic ultramafic rocks of the greenstone belt Rio das Velhas in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriela Magalhães da Fonseca

    2013-03-01

    Full Text Available Em Amarantina, distrito de Ouro Preto, encontram-se rochas ultramáficas expostas em duas áreas com cerca de 500 m² cada. As rochas afloram no Complexo do Bação, que é o embasamento gnáissico do greenstone belt Rio das Velhas, na porção central do Quadrilátero Ferrífero (QF. O interesse no estudo petrogenético desses corpos deve-se à preservação parcial de minerais ígneos, ausentes na maior parte das rochas ultramáficas totalmente metamorfizadas do QF. Entre essas rochas, destacam-se os esteatitos e os serpentinitos, devido a sua importância econômica. As rochas ultramáficas de Amarantina possuem textura equigranular, fato que as caracteriza como tendo origem plutônica, isto é, trata-se de metaperidotitos. Possuem grãos maiores de olivina, piroxênio e espinélio da rocha ígnea original distribuídos em matriz metamórfica fina com talco, serpentinas, cloritas, anfibólios e minerais opacos. Escassas arita (NiSbAs e breithauptita (NiSb foram formadas a partir de pentlandita durante o metamorfismo associado a hidrotermalismo. A comparação da composição química com a de um metakomatiito com textura spinifex do QF, bem como com rochas komatitiiticas de outras partes do mundo, mostra que os metaperidotitos são, quimicamente, semelhantes aos komatiitos não-desfalcados em alumínio. Portanto é provável que as rochas ultramáficas estudadas correspondam à porção plutônica do magmatismo komatitiitico do Grupo Nova Lima, que é a unidade basal do greenstone belt Rio das Velhas.In Amarantina, district of Ouro Preto (State of Minas Gerais, Brazil, ultramafic rock exposures are found along two areas of about 500 m² each. The rocks crop out in the Bação complex, which is the gneissic basement of the Rio das Velhas greenstone belt in the central portion of the Quadrilátero Ferrífero (QF. The interest in a petrogenetic study of the ultramafic rocks is the partial preservation of igneous minerals, which are not observed

  15. Petrography and the REE-composition of apatite in the Paleoproterozoic Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia

    Science.gov (United States)

    Joosu, Lauri; Lepland, Aivo; Kreitsmann, Timmu; Üpraus, Kärt; Roberts, Nick M. W.; Paiste, Päärn; Martin, Adam P.; Kirsimäe, Kalle

    2016-08-01

    The first globally significant phosphorous-rich deposits appear in the Paleoproterozoic at around 2 Ga, however, the specific triggers leading to apatite precipitation are debated. We examine phosphorous-rich rocks (up to 8 wt% P2O5) in 1.98-1.92 Ga old Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia. Phosphates in these rocks occur as locally derived and resedimented sand-to-gravel/pebble sized grains consisting of apatite-cemented muddy sediments. Phosphatic grains can be subdivided into four petrographic types (A-D), each has a distinct REE signature reflecting different early-to-late diagenetic conditions and/or metamorphic overprint. Pyrite containing petrographic type D, which typically has a flat REE pattern, negative Ce anomaly and positive Eu anomaly, is the best preserved of the four types and best records conditions present during apatite precipitation. Type D phosphatic grains precipitated under (sub)oxic basinal conditions with a significant hydrothermal influence. These characteristics are similar to Zaonega Formation phosphates of NW Russia's Onega Basin, and consistent with phosphogenesis triggered by the development of anoxic(sulfidic)-(sub)oxic redoxclines at shallow sediment depth during the Paleoproterozoic.

  16. Geochemistry and petrogenesis of the K-rich 'Bongo-type' granitoids in the Paleoproterozoic Bole-Nangodi greenstone belt of Ghana

    Science.gov (United States)

    Abitty, Emmanuel K.; Dampare, Samuel B.; Nude, Prosper M.; Asiedu, Daniel K.

    2016-10-01

    The 'Bongo-type' granitoids intrude the northern portion (where it cross cuts the Tarkwaian), central and south-central portions of the Bole-Nangodi greenstone belt in Ghana. The non-foliated, porphyritic granitoids are characterised by microcline (5-18 mm), often set in a medium to fine grained matrix of quartz and plagioclase, contains granular quartz and show incipient development of mymerkites under thin section. The major mafic phases are a brownish-green variety of hornblende ± biotite, with sphene, epidote and apatite occurring as accessory minerals. The pink looking 'Bongo-type' granitoids are classified as granites with subordinate granodiorites and quartz monzonites. Whole-rock geochemical analyses show that the granitoids are magnesian and metaluminous to weakly peraluminous. On the basis of their Th-Co-K2O and SiO2 contents, the granitoids classified as high-K calc-alkaline and shoshonite series rocks. They show enriched LILE trends, decoupled LILE-HFSE patterns, negative Ta-Nb anomaly, pronounced negative Ti anomaly and variable positive and negative Sr anomalies. The K-rich granitoids from the middle and south-central portions of the Bole-Nangodi belt show the lowest concentrations of LILE and some HFSE with the most prominent negative Ti and Si anomalies. The 'Bongo-type' granitoids show I-type characteristics. Based on Ba-U-Th concentrations, they are interpreted to have had some interaction with crustal materials or some influence of subducted sediments. The granitoids unequivocally show subduction-related signatures and mimic high silica adakites (HSA). They show evidence of being emplaced in a volcanic arc geotectonic environment. Their geochemical similarities to A-type granitoids, however, suggest an arc-back-arc tectonic setting.

  17. Potential of thermal emissivity for mapping of greenstone rocks and associated granitoids of Hutti Maski Schist belt, Karnataka

    OpenAIRE

    Guha, A.; K.Vinod Kumar

    2014-01-01

    In the present study, different temperature-emissivity separation algorithms were used to derive emissivity images based on processing of ASTER( Advanced spaceborne thermal emission and reflection radiometer) thermal bands. These emissivity images have been compared with each other in terms of geological information for mapping of major rock types in Hutti Maski schist Belt and its associated granitoids. Thermal emissivity images are analyzed conjugately with thermal radiance image, ...

  18. Re-Os Abundance and Isotope Systematics of Al-undepleted Komatiites in the Kidd-Munro Assemblage: Results From Dundonald Beach, Abitibi Greenstone Belt, Canada

    Science.gov (United States)

    Gangopadhyay, A.; Sproule, R. A.; Walker, R. J.; Lesher, C. M.

    2004-05-01

    Petrographic and geochemical studies suggest that all Precambrian komatiites have undergone variable degrees of weathering, hydrothermal alteration and metamorphism. The effects of these secondary processes in some suites have manifested into large-scale open-system behavior of Re-Os elemental and isotope systematics of whole rocks, which, in some cases, yield inaccurate age and large uncertainties in calculated initial Os isotopic compositions of the emplaced lavas. Thus, some of the previous Os isotopic studies of Precambrian komatiites for which the crystallization ages were known from other radiogenic isotope systematics (e.g., Sm-Nd, Pb-Pb) have relied on Os-rich, relatively well-preserved primary igneous minerals (e.g., olivine and chromite) in order to calculate the initial Os isotopic compositions of the host lavas. Consequently, the whole-rock concentrations of Re and Os in these altered komatiites can neither be used to infer their concentrations in the parental liquids nor their partitioning behaviors during generation and subsequent differentiation of komatiitic magmas. Here we report the Re-Os concentrations of whole rocks from a suite of ca. 2.7-Ga komatiitic rocks from the Dundonald Beach area, part of the Kidd-Munro volcanic assemblage in the Abitibi greenstone belt, Canada. We show that it is possible to calculate the original Re concentrations in the emplaced lavas, and to estimate the gain or loss of Re through comparison of their measured concentrations and those recalculated from their correlations with other incompatible, yet relatively immobile major oxide and trace elements (e.g., Al2O3, Zr, Hf, Yb). We also demonstrate the statistical significance of this scheme of correction with the reduced values of MSWD (by an order of magnitude) and respective uncertainties in slope (by 2-3 orders of magnitude) of regressions involving Re and the immobile elements. Based on the absence of a correlation between loss of Re and the Os isotopic

  19. The provenance and Sm/Nd Model ages of siliciclastic supracrustal rocks of the Faina and Santa Rita Greenstone belts, Goias, Brazil

    International Nuclear Information System (INIS)

    The Faina and Santa Rita greenstone belts are two N 60 deg C W trending synclinoria separated by a N 30 deg C E strike-slip fault and rest allochtonous on the adjacent Uva and Caicara granite-gneiss complexes. The belts are made up of lower metakomatiites, followed by metabasalts and thick metasedimentary sequences deposited under contrasting paleogeographic settings. In Faina, the sequence consists of two complete shelf cycles, the first resting on basalts by an erosional unconformity. In Santa Rita, the basalts give gradually place to carbonaceous metashales, unconformably overlain by metarhythmites. Provenance based on trace element geochemistry, mineral chemistry of chloride and muscovite, source-are modeling and REE elements indicate that protoliths of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita formed under the influence of a source area dominated by mafic ultramafic rocks, whilst during the sedimentation of the second shelf cycle and the metarhythmites of Santa Rita the source-area was dominated by TTG granitoids. Sm-Nd model ages of the lower sedimentary packages vary between 3.0 and 2.8 Ga and the upper between 2.7 and 2.6 Ga. These intervals coincide, respectively, with the estimated age of the underlying, and with the Sm-Nd, Rb-Sr e U-Pb ages of the main granitoids and gneisses of the adjacent complexes. The same data indicate that, during the sedimentation of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita, both basins had independent source-areas, but shared the same source during the upper sections. Weathering nature and intensity of the source-area calculated by means of geochemical a data suggest that the dramatic change of provenance from the lower to the upper sections is due to the shift from tectonically stable to unstable regimes, interpreted as resulting from the emergence of the island arc whose roots are represented by the adjacent granite-gneiss complexes. (author)

  20. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

    Science.gov (United States)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

    2016-03-01

    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  1. Oceanic plateau model for continental crustal growth in the Archaean: A case study from the Kostomuksha greenstone belt, NW Baltic Shield

    Science.gov (United States)

    Samsonov, A. V.; Shchipansky, A. A.; Jochum, K. P.; Mezger, K.; Hofmann, A. W.; Puchtel, I. S.

    1998-02-01

    Field studies combined with chemical and isotope data indicate that the Kostomuksha greenstone belt in the NW Baltic Shield consists of two lithotectonic terranes, one mafic igneous and the other sedimentary, separated by a major shear zone. The former contains submarine komatiite-basalt lavas and volcaniclastic lithologies, and the latter is composed of shelf-type rocks and BIF. Komatiitic and basaltic samples yield Sm-Nd and Pb-Pb isochron ages of 2843+/-39 and 2813+/-78 Ma, respectively. Their trace-element compositions resemble those of recent Pacific oceanic flood basalts with primitive-mantle normalized Nb/Th of 1.5-2.1 and Nb/La of 1.0-1.5. This is in sharp contrast with island arc and most continental magmas, which are characterized by Nb/(Th,La)N≪1. Calculated initial Nd-isotope compositions (ɛNd(T)=+2.8 to +3.4) plot close to an evolution line previously inferred for major orogens (``MOMO''), which is also consistent with the compositions of recent oceanic plateaux. The high liquidus temperatures of the komatiite magmas (1550°C) and their Al-depleted nature require an unusually hot (1770°C) mantle source for the lavas (>200°C hotter than the ambient mantle at 2.8 Ga), and are consistent with their formation in a deep mantle plume in equilibrium with residual garnet. This plume had the thermal potential to produce oceanic crust with an average thickness of ~30 km underlain by a permanently buoyant refractory lithospheric mantle keel. Nb/U ratios in the komatiites and basalts calculated on the basis of Th-U-Pb relationships range from 35 to 47 and are thus similar to those observed in modern MORB and OIB. This implies that some magma source regions of the Kostomuksha lavas have undergone a degree of continental material extraction comparable with those found in the modern mantle. The mafic terrane is interpreted as a remnant of the upper crustal part of an Archaean oceanic plateau. When the newly formed plateau reached the active continental margin

  2. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

    Science.gov (United States)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

    2016-10-01

    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  3. The geology of the Morro Velho gold deposit in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Vial, Diogenes Scipioni; DeWitt, Ed; Lobato, Lydia Maria; Thorman, Charles H.

    2007-01-01

    The Morro Velho gold deposit, Quadrilátero Ferrífero region, Minas Gerais, Brazil, is hosted by rocks at the base of the Archean Rio das Velhas greenstone belt. The deposit occurs within a thick carbonaceous phyllite package, containing intercalations of felsic and intermediate volcaniclastic rocks and dolomites. Considering the temporal and spatial association of the deposit with the Rio das Velhas orogeny, and location in close proximity to a major NNW-trending fault zone, it can be classified as an orogenic gold deposit. Hydrothermal activity was characterized by intense enrichment in alteration zones of carbonates, sulfides, chlorite, white mica±biotite, albite and quartz, as described in other Archean lode-type gold ores. Two types of ore occur in the deposit: dark gray quartz veins and sulfide-rich gold orebodies. The sulfide-rich orebodies range from disseminated concentrations of sulfide minerals to massive sulfide bodies. The sulfide assemblage comprises (by volume), on average, 74% pyrrhotite, 17% arsenopyrite, 8% pyrite and 1% chalcopyrite. The orebodies have a long axis parallel to the local stretching lineation, with continuity down the plunge of fold axis for at least 4.8 km. The group of rocks hosting the Morro Velho gold mineralization is locally referred to as lapa seca. These were isoclinally folded and metamorphosed prior to gold mineralization. The lapa seca and the orebodies it hosts are distributed in five main tight folds related to F1 (the best examples are the X, Main and South orebodies, in level 25), which are disrupted by NE- to E-striking shear zones. Textural features indicate that the sulfide mineralization postdated regional peak metamorphism, and that the massive sulfide ore has subsequently been neither metamorphosed nor deformed. Lead isotope ratios indicate a model age of 2.82 ± 0.05 Ga for both sulfide and gold mineralization. The lapa seca are interpreted as the results of a pre-gold alteration process and may be

  4. Multiple sulfur and carbon isotope composition of sediments from the Belingwe Greenstone Belt (Zimbabwe): A biogenic methane regulation on mass independent fractionation of sulfur during the Neoarchean?

    Science.gov (United States)

    Thomazo, Christophe; Nisbet, Euan G.; Grassineau, Nathalie V.; Peters, Marc; Strauss, Harald

    2013-11-01

    To explore the linkage between mass-independent sulfur isotope fractionation (MIF-S) and δ13Corg excursions during the Neoarchean, as well as the contemporary redox state and biogeochemical cycling of carbon and sulfur, we report the results of a detailed carbon and multiple sulfur (δ34S, δ33S, δ36S) isotopic study of the ∼2.7 Ga Manjeri and ∼2.65 Ga Cheshire formations of the Ngezi Group (Belingwe Greenstone Belt, Zimbabwe). Multiple sulfur isotope data show non-zero Δ33S and Δ36S values for sediments older than 2.4 Ga (i.e. prior to the Great Oxidation Event, GOE), indicating MIF-S thought to be associated with low atmospheric oxygen concentration. However, in several 2.7-2.5 Ga Neoarchean localities, small-scale variations in MIF-S signal (magnitude) seem to correlate with negative excursion in δ13Corg, possibly reflecting a global connection between the relative reaction rate of different MIF-S source reaction and sulfur exit channels and the biogenic flux of methane into the atmosphere during periods of localized, microbiologically mediated, shallow surface-water oxygenation. The Manjeri Formation black shales studied here display a wide range of δ13Corg between -35.4‰ and -16.2‰ (average of -30.3 ± 6.0‰, 1σ), while the Cheshire Formation shales have δ13Corg between -47.7‰ and -35.1‰ (average -41.3 ± 3‰, 1σ). The δ34S values of sedimentary sulfides from Manjeri Formation vary between -15.15‰ and +2.37‰ (average -1.71 ± 4.76‰, 1σ), showing very small and mostly negative Δ33S values varying from -0.58‰ to 0.87‰ (average 0.02 ± 0.43‰, 1σ). Cheshire Formation black shale sulfide samples measured in this study have δ34S values ranging from -2.11‰ to 2.39‰ (average 0.25 ± 1.08‰, 1σ) and near zero and solely positive Δ33S anomalies between 0.14‰ and 1.17‰ (average 0.56 ± 0.29‰, 1σ). Moreover, Δ36S/Δ33S in the two formations are comparable with a slope of -1.38 (Manjeri Formation) and -1.67 (Cheshire

  5. High-resolution quadruple sulfur isotope analyses of 3.2 Ga pyrite from the Barberton Greenstone Belt in South Africa reveal distinct environmental controls on sulfide isotopic arrays

    NARCIS (Netherlands)

    Roerdink, D.L.; Mason, P.R.D.; Whitehouse, M.J.; Reimer, T.

    2013-01-01

    Multiple sulfur isotopes in Paleoarchean pyrite record valuable information on atmospheric processes and emerging microbial activity in the early sulfur cycle. Here, we report quadruple sulfur isotope data (32S, 33S, 34S, 36S) analyzed by secondary ion mass spectrometry from pyrite in a 3.26–3.23 Ga

  6. Rb–Sr and Sm–Nd isotope systematics and geochemical studies on metavolcanic rocks from Peddavura greenstone belt: Evidence for presence of Mesoarchean continental crust in easternmost part of Dharwar Craton, India

    Indian Academy of Sciences (India)

    M Rajamanickam; S Balakrishnan; R Bhutani

    2014-07-01

    Linear, north–south trending Peddavura greenstone belt occurs in easternmost part of the Dharwar Craton. It consists of pillowed basalts, basaltic andesites, andesites (BBA) and rhyolites interlayered with ferruginous chert that were formed under submarine condition. Rhyolites were divided into type-I and II based on their REE abundances and HREE fractionation. Rb–Sr and Sm–Nd isotope studies were carried out on the rock types to understand the evolution of the Dharwar Craton. Due to source heterogeneity Sm–Nd isotope system has not yielded any precise age. Rb–Sr whole-rock isochron age of 2551 ± 19 (MSWD = 1.16) Ma for BBA group could represent time of seafloor metamorphism after the formation of basaltic rocks. Magmas representing BBA group of samples do not show evidence for crustal contamination while magmas representing type-II rhyolites had undergone variable extents of assimilation of Mesoarchean continental crust (< 3.3 Ga) as evident from their initial Nd isotope values. Trace element and Nd isotope characteristics of type I rhyolites are consistent with model of generation of their magmas by partial melting of mixed sources consisting of basalt and oceanic sediments with continental crustal components. Thus this study shows evidence for presence of Mesoarchean continental crust in Peddavura area in eastern part of Dharwar Craton.

  7. The 3.26-3.24 Ga Barberton asteroid impact cluster: Tests of tectonic and magmatic consequences, Pilbara Craton, Western Australia

    Science.gov (United States)

    Glikson, Andrew; Vickers, John

    2006-01-01

    The location in the Barberton Greenstone Belt (Kaapvaal Craton) of ∼3.26-3.24 Ga asteroid impact ejecta units at, and immediately above, a sharp break between a > 12 km-thick mafic-ultramafic volcanic crust (Onverwacht Group ∼3.55-3.26 Ga, including the ∼3.298 > 3.258 Ga Mendon Formation) and a turbidite-felsic volcanic rift-facies association (Fig Tree Group ∼3.258-3.225 Ga), potentially represents the first documented example of cause-effect relations between extraterrestrial bombardment and major tectonic and igneous events [D.R. Lowe, G.R. Byerly, F. Asaro, F.T. Kyte, Geological and geochemical record of 3400 Ma old terrestrial meteorite impacts, Science 245 (1989) 959-962; D.R. Lowe, G.R. Byerly, F.T. Kyte, A. Shukolyukov, F. Asaro, A. Krull, Spherule beds 3.47-3.34 Ga-old in the Barberton greenstone belt, South Africa: a record of large meteorite impacts and their influence on early crustal and biological evolution, Astrobiology 3 (2003) 7-48; A.Y. Glikson, The astronomical connection of terrestrial evolution: crustal effects of post-3.8 Ga mega-impact clusters and evidence for major 3.2 ± 0.1 Ga bombardment of the Earth-Moon system, J. Geodyn. 32 (2001) 205-229]. Here we correlate this boundary with a contemporaneous break and peak magmatic and faulting events in the Pilbara Craton, represented by the truncation of a 3.255-3.235 Ga-old volcanic sequence (Sulphur Springs Group-SSG) by a turbidite-banded iron formation-felsic volcanic association (Pincunah Hill Formation, basal Gorge Creek Group). These events are accompanied by ∼3.252-3.235 Ga granitoids (Cleland plutonic suite). The top of the komatiite-tholeiite-rhyolite sequence of the SSG is associated with a marker chert defined at 3.238 ± 3-3.235 ± 3 Ga, abruptly overlain by an olistostrome consisting of mega-clasts of felsic volcanics, chert and siltstone up to 250 × 150 m-large, intercalated with siliciclastic sedimentary rocks and felsic volcanics (Pincunah Hill Formation-basal Gorge

  8. Timing of deposition and provenance of stromatolitic carbonates from the 2.7 Ga. Belingwe Greenstone Belt/Zimbabwe Craton: constraints from Pb-Pb and Sm-Nd systematics

    International Nuclear Information System (INIS)

    Full text: Pb-Pb isochron ages have been obtained for stromatolitic limestones from the late Archaean Belingwe Greenstone Belt, providing direct age constraints on the deposition of these shallow water marine sediments. Samples from the Manjeri Formation and stratigraphically upper Cheshire Formation yield ages of 2700±49 Ma (MSWD = 13) and 2543±53 Ma (MSWD 5.6), respectively. These data are in agreement with published U-Pb zircon and Pb-Pb whole rock ages of stratigraphically enclosing volcanics, and we interpret our Pb-Pb ages as the timing of diagenesis and minimum age of carbonate precipitation. A 2400±53 Ma age (MSWD = 0.66) for one sample from the Cheshire Formation is considered to be unrelated to a depositional/ diagenetic event. We infer that this age may reflect a craton wide thermal/ chemical disturbance event or tectonic activity along the crustal-scale Mtshingwe fault. Carbonate samples collected from a sheared contact have also been subjected to Pb isotope analysis in an attempt to obtain absolute age constraints on deformation. Geological information precludes this age from being meaningful and this, along with a high MSWD value, indicates open-system behaviour and/or mixing relationships between isotopic end-members. A step-dissolution procedure using dilute acetic and hydrochloric acids has been applied to sub-samples from individual hand-specimens. This technique enables to recover radiogenic and common Pb, and thus is of particular utility where single hand-specimens are to be dated. Calculated model μ-values for Manjeri and Cheshire limestones are 8.4±0.02 and 9.02±0.01, similar to values for ca. 3.5 and 2.9 Ga.- old Archaean basement units adjacent to the Belingwe Belt. Negative ε-Nd (T-deposition) and ∫Sm/Nd suggest derivation of the REE from old, LREE enriched continental crust. 2-stage Nd model ages for the carbonates indicate that precursor rocks were extracted from the mantle 3.5 - 3.8 Ga. (Cheshire Formation) and 3.3 Ga. (Manjeri

  9. Isotope age of the rare metal pegmatite formation in the Kolmozero-Voron'ya greenstone belt (Kola region of the Fennoscandian shield): U-Pb (TIMS) microlite and tourmaline dating

    Science.gov (United States)

    Kudryashov, Nikolay; Lyalina, Ludmila; Mokrushin, Artem; Zozulya, Dmitry; Groshev, Nikolay; Steshenko, Ekaterina; Kunakkuzin, Evgeniy

    2016-04-01

    The Kolmozero-Voron'ya greenstone belt is located in the central suture zone, which separates the Murmansk block from the Central-Kola and the Keivy blocks. The belt is represented by volcano-sedimentary rocks of Archaean age of 2.9-2.5 Ga. Rare metal pegmatites (Li, Cs with accessory Nb, Ta, and Be) occur among amphibolite and gabbroid intrusions in the northwestern and southeastern parts of the belt. According to the Rb-Sr data, the age of pegmatites was considered to be 2.7 Ga. Until recently there was no generally accepted point of view on the origin of pegmatites. Now we have isotopic data for a range of rock complexes that could pretend to be parental granites for the rare metal pegmatites. These are granodiorites with the zircon age of 2733±Ma, and microcline and tourmaline granites, which Pb-Pb isochronal age on tourmaline from the tourmaline granite located near the deposit is estimated to be 2520±70 Ma. The pegmatite field of the Vasin Myl'k deposit with the lepidolite--albite--microcline--spodumene--pollucite association is located among amphibolites in the northwestern part of the belt. The deposit is represented by subparallel low-angle zoned veins up to 220 m long and 5 m thick dipping in the southeastern direction at an angle of 10° too 30°. The minerals of the columbite--tonalite group from Vasin Myl'k deposit include microlite, simpsonite, and torolite, and are the oldest among different minerals represented by several generations in pegmatites under consideration. Zircons from the pegmatites are mostly represented by crystals with the structure affected by the action of fluids that put certain restrictions on its use as a geochronometer of the crystallization process. Microlite from the pegmatite taken from the dump of a prospecting drill hole was used for U--Pb (TIMS). The mineral is represented by 0.5--1.0 mm long euhedral octahedral crystals. It is brown in color, and transparent. The microlite crystals were preliminarily cleaned from

  10. Geodynamic evolution of the West Africa between 2.2 and 2 Ga: the Archaean style of the Birimian greenstone belts and the sedimentary basins in northeastern Ivory-Coast; Evolution de l`Afrique de l`Ouest entre 2,2 Ga et 2 Ga: le style archeen des ceintures vertes et des ensembles sedimentaires birimiens du nord-est de la Cote-d`Ivoire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, M.; Pouclet, A. [Orleans Univ., 45 (France); Delor, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Simeon, Y. [ANTEA, 45 - Orleans (France); Alric, G. [Etablissements Binou, 27 - Le Mesnil-Fuguet (France)

    1996-12-31

    The litho-structural features of Palaeo-proterozoic terrains of northeastern Ivory-Coast, greenstones belts and then sedimentary (basin Birimian), are similar to those of Archaean terrains. Their early deformation is only voluminal deformation due to granitoid intrusions, mainly between 2.2 and 2.16 Ga. The shortening deformation (main deformation) is expressed by right folds and transcurrent shear zones ca 2.1 Ga. Neither thrust deformation nor high pressure metamorphic assemblages are known. This pattern of flexible and hot crust, at least between 2.2 and 2.16 Ga, is pole apart to a collisional pattern, proposed for West African Craton by some authors. The Archaean/Palaeo-proterozoic boundary would not represent a drastic change of the geodynamic evolution of the crust. (authors). 60 refs., 5 figs., 6 photos.

  11. Geology of East Egypt greenstone field in Neoproterozoic isoand arc: Reconstruction of Iron formation sedimentary environment.

    Science.gov (United States)

    Kiyokawa, S.; Suzuki, T.

    2015-12-01

    Geology of East Egypt greenstone-granit belt which is northern part of Nubia shield was identified neoproterozoic island arc amalgamated sections. There are several iron formation within these greenstone belt. Age data shows this iron formation may be overlaped during 700 Ma Snowball period, how ever, there is no detail report of well preserved ice related evidences. We now started detail field work for identified tectonic reconstruction, original stratigraphy around Iron formation and sedimentary environment during the iron formation sedimentation area. East Egyptian shield was divided three geology, Proterozoic greenstone complex, 700-600 Granitic domes and cover sequence (Hammamet Group). We focus three area to identified sedimentary environment of iron sedimentation. Along the north-south trend of Wadi EL Dabban area are, we named Wadi branch as West site is RW-0 ~ 12, East site is RE-0 ~ 12 from north to south. Northern area is structurally moderate, southern portion is north dipping. Southern portion was intruded by granite and several place contain granitic dikes. Northeast to eastern area are identified younger sedimentary sequence (Hammamat Group) which is unconformablly overlay on the other iron formation bearing greenstone belt. Structurally these area is divided four units. Wadi was divided by right-lateral strike-ship fault. The displacement are more than 3 km. Also north dipping faults are identified.East-West trend fault are divided two units. It is divided NE, SE, NW and NS units.SW unit is most well preserved thick sequence of the Iron formation. SW unit is well preserved iron formation sequence within thick volcaniclastics. This unit mostly north dipping around 40-60 degree. Structural repetition in not well understand. Reconstract stratigraphy in this unit is at least 4000m in thickness. 5 member is identified in this sequence. Several thin iron formations are observed with in pillow lava and volcaniclastic sequence. These very thick

  12. Microstructural analysis of a subhorizontal gold-quartz vein deposit at Donalda,Abitibi greenstone belt,Canada: Implications for hydrodynamic regime%加拿大Abitibi绿岩带Donalda金矿近水平含金石英脉的显微构造分析及其对成矿流体动力学的指示

    Institute of Scientific and Technical Information of China (English)

    池国祥; Jayanta Guha

    2011-01-01

    位于加拿大Abitibi绿岩带南部的Donalda金矿床主要由近水平的、与剪切带近垂直的含金石英脉组成,矿脉厚度0.3~0.5m,含大量与脉壁平行的条带,指示多期次裂隙扩张和矿物沉淀。原生石英c-轴方位测量显示石英生长方向垂直于脉壁,指示断裂属张性,矿物沉淀属空间充填。显微裂隙、细脉及流体包裹体面(FIPs)的方位测量指示原生矿物受到了近直立的最大主压应力(σ1)作用,与区域性的、近水平的南北向挤压应力不符。这一矛盾现象可用流体压力在超静岩和静水压力之间周期性变化及近水平断裂的周期性张开与闭合来解释。当流体压力大于静岩压力时,断裂张开,原生矿物沉淀,而当流体压力减小时,断裂上盘往下垮,两盘突出的矿物碰撞、碾压形成与脉壁平行的变形条带。由于断裂两盘岩石不是沿整条断裂都互相接触,两盘相顶部分承受的垂直应力大于水平方向的挤压应力,这就解释了为什么显微构造指示近直立的最大主压应力(σ1)。这个流体-构造模式支持断层阀模式,并且无须改变区域应力场就可解释脉体内局部主压应力的变化。%The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists mainly of a subhorizontal gold-quartz vein perpendicular to subvertical shear zones.The 0.3-0.5 m thick vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening and mineral precipitation.Measurement of the c-axis of primary growth quartz indicates that quartz preferentially grew perpendicular to the fracture,suggesting open space filling and/or extensional nature of the fracture.Measurement of the orientations of microfractures,veinlets and fluid-inclusion planes(FIPs) crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum principal stress(σ 1),which is

  13. The origin of carbonaceous matter in pre-3.0 Ga greenstone terrains: A review and new evidence from the 3.42 Ga Buck Reef Chert

    Science.gov (United States)

    Tice, Michael M.; Lowe, Donald R.

    2006-06-01

    The geological record of carbonaceous matter from at least 3.5 Ga to the end of the Precambrian is fundamentally continuous in terms of carbonaceous matter structure, composition, environments of deposition/preservation, and abundance in host rocks. No abiotic processes are currently known to be capable of producing continuity in all four of these properties. Although this broad view of the geological record does not prove that life had arisen by 3.5 Ga, the end of the early Archean, it suggests a working hypothesis: most if not all carbonaceous matter present in rocks older than 3.0 Ga was produced by living organisms. This hypothesis must be tested by studies of specific early geological units designed to explore the form, distribution, and origin of enclosed carbonaceous matter. The carbonaceous, environmentally diverse 3416 Ma Buck Reef Chert (BRC) of the Barberton greenstone belt, South Africa, provides an opportunity for such a study. Upward facies progressions in the BRC reflect deposition in environments ranging from shallow marine evaporitic brine ponds to a storm- and wave-active shelf to a deep, low-energy basinal setting below storm wave base. Abundances and ratios of Al 2O 3, Zr, TiO 2, and Cr track inputs of various types of volcaniclastic and terrigenous clastic materials. In particular, Zr/Al 2O 3 and Zr serve as proxies for concentration of windblown dust and, indirectly, as proxies for sedimentation rate. Cu, Zn, Ni, and FeO were concentrated in the most slowly deposited transitional and basinal sediments, inconsistent with a hydrothermal setting but consistent with a normal marine setting. The distribution of microfacies defined by associations and layering of clastic, ferruginous, and carbonaceous grains correlates with facies transitions. Fine carbonaceous laminations, which occur only in shallow platform settings, represent photosynthetic microbial mats. These were ripped up and the debris widely redistributed in shallow and deep water by

  14. Apartheid's Alcatraz: The Barberton Prison Complex During the Early 1980s - Part Two

    Directory of Open Access Journals (Sweden)

    Stephen Allister Peté.

    2015-07-01

    Full Text Available The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this article is on the treatment of "normal" as opposed to "political" prisoners during the period in question, allowing the "voices" of ordinary prisoners – often sidelined and silenced – to be brought to the fore. The Barberton Prison Complex is examined through the lens of public discourse, as reflected in a wide range of South African newspapers published at the time. By analysing a large number of reports dealing with events at Barberton during the period in question, in both English and Afrikaans language newspapers, as well as in both politically conservative and politically liberal newspapers, this article attempts to capture both the "smell" and the "feel" of what it was like to be imprisoned in one of apartheid's toughest prison complexes. Furthermore, this article seeks to show that – despite legislative measures restricting the publication of information on conditions inside apartheid prisons – the press was able to provide a steady stream of information to the South African public on the shocking events which occurred at Barberton during the period in question. Part Two of the article examines a string of violent incidents which occurred within the Barberton Prison Complex during the course of 1983, leading to nine inmate deaths. The response of the authorities to this orgy of violence at Barberton is discussed, including the findings of a committee of enquiry. It is concluded that the events at Barberton during the early 1980s were

  15. Apartheid's Alcatraz: The Barberton Prison Complex During the Early 1980s - Part One

    Directory of Open Access Journals (Sweden)

    Stephen Allister Peté

    2015-07-01

    Full Text Available The purpose of this two-part article is to examine in detail the public discourse surrounding the Barberton Prison Complex during the early 1980s, at the height of the apartheid era. The prisons within the Barberton Prison Complex were notorious as being among the most punitive of the many prisons within apartheid South Africa. Barberton was the place to which the most dangerous and intractable prisoners were sent to serve their sentences, making it apartheid's "Alcatraz". The focus of this article is on the treatment of "normal" as opposed to "political" prisoners during the period in question, allowing the "voices" of ordinary prisoners – often sidelined and silenced – to be brought to the fore. The Barberton Prison Complex is examined through the lens of public discourse, as reflected in a wide range of South African newspapers published at the time. By analysing a large number of reports dealing with events at Barberton during the period in question, in both English and Afrikaans language newspapers, as well as in both politically conservative and politically liberal newspapers, this article attempts to capture both the "smell" and the "feel" of what it was like to be imprisoned in one of apartheid's toughest prison complexes. Furthermore, this article seeks to show that – despite legislative measures restricting the publication of information on conditions inside apartheid prisons – the press was able to provide a steady stream of information to the South African public on the shocking events which occurred at Barberton during the period in question. Part One of this article deals with the deaths of three prisoners and the injury of many others during a day of violence at the Barberton prison farm on 29 December 1982, as well as the broader political implications of the criminal trial - known as the "heat exhaustion trial" - which followed. It is contended that the events surrounding the infamous "heat exhaustion trial" may be seen

  16. Late Archean intermediate-felsic magmatism of the South Vygozersky and Kamennozersky greenstone structures of Central Karelia

    Science.gov (United States)

    Myskova, T. A.; Zhitnikova, I. A.; L'vov, P. A.

    2015-07-01

    The geochemistry and zircon geochronology (U-Pb, SHRIMP-II) of Late Archean intermediate-felsic dikes and plagiogranites of the Shilossky massif of the South Vygozersky and Kamennozersky greenstone belts of Central Karelia were studied. Subvolcanic rocks of the dike complex vary in composition from andesitobasalts to rhyolites, in structural-textural peculiarities, and in the formation age, from 2862 ± 8 to 2785 ± 15 Ma. Compositionally and geochronologically (2853 ± 11 Ma), plagiogranites of the Shilossky massif of the South Vygozersky greenstone belts are close to the most ancient dacite and granodiorite porphyry dikes. Dikes intruded synchronously with intrusion of plagiogranites over a period of at least 70 m.y. Geochronologically, subvolcanic rocks of the dike complex and plagiogranites of the Shilossky massif are similar to granitoids of the TTG assemblages of I- and M-type granites. The Sm-Nd model age of some dikes (2970-2880 Ma) is close to the age of rock crystallization, which is evidence in favor of juvenile origin of magma. Dikes with more ancient model age (3050 Ma) are presumed to contain crustal material. Variations in age and ɛNd (from -2.7 to +2.9) indicate the absence of a unified magmatic source.

  17. Unravelling atmospheric photolysis and ocean redox chemistry from Paleoarchean pyrite : a multiple sulfur and iron stable isotope study

    NARCIS (Netherlands)

    Galić, A.

    2015-01-01

    This thesis brought together four individual studies on the geochemistry of three recently obtained drill cores from the Barberton Greenstone Belt, South Africa. These data were used to provide a synthesis of the iron and sulfur cycles in the Paleoarchean, with a particular focus on the nature and o

  18. Mesoarchean sanukitoid rocks of the Rio Maria Granite-Greenstone Terrane, Amazonian craton, Brazil

    Science.gov (United States)

    de Oliveira, Marcelo Augusto; Dall'Agnol, Roberto; Althoff, Fernando Jacques; da Silva Leite, Albano Antonio

    2009-02-01

    The Archean sanukitoid Rio Maria Granodiorite yielded zircon ages of ˜2.87 Ga and is exposed in large domains of the Rio Maria Granite-Greenstone Terrane, southeastern Amazonian craton. It is intrusive in the greenstone belts of the Andorinhas Supergroup, in the Arco Verde Tonalite and Caracol Tonalitic Complex (older TTGs). Archean potassic leucogranites, younger TTGs and the Paleoproterozoic granites of Jamon Suite are intrusive in the Rio Maria Granodiorite. The more abundant rocks of the Rio Maria Granodiorite have granodioritic composition and display medium to coarse even-grained textures. These rocks show generally a gray color with greenish shades due to strongly saussuritized plagioclase, and weak WNW-ESE striking foliation. The significant geochemical contrasts between the occurrences of Rio Maria Granodiorite in different areas suggest that this unit corresponds in fact to a granodioritic suite of rocks derived from similar but distinct magmas. Mingling processes involving the Rio Maria Granodiorite and similar mafic to intermediate magmas are able to explain the constant occurrence of mafic enclaves in the granodiorite. The associated intermediate rocks occur mainly near Bannach, where mostly quartz diorite and quartz monzodiorite are exposed. The dominant rocks are mesocratic, dark-green rocks, with fine to coarse even-grained texture. The Rio Maria Granodiorite and associated intermediate rocks show similar textural and mineralogical aspects. They follow the calc-alkaline series trend in some diagrams. However, they have high-Mg#, Cr, and Ni conjugate with high contents of large ion lithophile elements (LILEs), typical of sanukitoids series. The patterns of rare earth elements of different rocks are similar, with pronounced enrichment in light rare earth elements (LREEs) and strong to moderate fractionation of heavy rare earth elements (HREEs). Field aspects and petrographic and geochemical characteristics denote that the granodiorites and

  19. Earth's Archean Impact Record In The ICDP Drilling "Barberton Mountain Land".

    Science.gov (United States)

    Fritz, Jörg; Schmitt, Ralf-Thomas; Reimold, Uwe; Koeberl, Christian; Mc Donald, Ian; Hofmann, Axel; Luais, Beatrice

    2013-04-01

    The marine meta-sedimentary successions in the "Barberton Mountain Land" are formed by Archean volcanic and sedimentary rocks including the oldest known impact ejecta layers on Earth. The chemical signature (high iridium concentrations, chromium isotopic ratios) of some of these up to tens of cm thick Archean spherule layers advocate that these ejecta deposits represent mainly extraterrestrial material [1]. These ejecta layers contain millimetre sized spherules that are larger and accumulated thicker layers compared to any impact ejecta layer known from Phanerozoic sediments, including the global ejecta layer of the Chicxulub impact catering event terminating the Mesozoic era of Earth's history [2]. The Archean spherule layers are interpreted as products of large impacts by 20 to >100 km diameter objects [3, 4]. Identifying traces of mega-impacts in Earth's ancient history could be of relevance for the evolution of atmosphere, biosphere, and parts of the Earth's crust during that time. In addition, recognizing global stratigraphic marker horizons is highly valuable for inter-correlating sedimentary successions between Archean cratons [5]. However estimates regarding size of the impact event and correlations between the different outcrops in the Barberton mountain land are complicated by post depositional alterations of the tectonically deformed sediments [6, 7]. The relatively fresh samples recovered from below the water table during the 2011-2012 ICDP drilling "Barberton Mountain Land" are promising samples to investigate and to discriminate primary and secondary features of these rare rocks. We plan to conduct 1) petrographic, micro-chemical and mineralogical characterization of the impact ejecta layers, 2) bulk chemical analyses of major and trace elements, and 3) LAICP- MS elemental mapping of platinum group element (PGE) distributions. and elemental analyses of moderately siderophile elements. This aims at 1) characterization of the ejecta layers, 2

  20. Age range of formation of sedimentary-volcanogenic complex of the Vetreny Belt (the southeast of the Baltic Shield)

    Science.gov (United States)

    Mezhelovskaya, S. V.; Korsakov, A. K.; Mezhelovskii, A. D.; Bibikova, E. V.

    2016-03-01

    As a result of studying the Vetreny Belt greenstone structure (the southeast of the Baltic Shield), zircons from terrigenous deposits of the Toksha Formation, underlying the section of the sedimentary-volcanogenic complex, and zircons of the Vetreny Belt Formation, deposits of which crown the section, were dated. The results of analysis of age data of detrital zircons from quartzites of the Toksha Formation indicate that Mesoarchean greenstone complexes and paleo-Archean granitogneisses of the Vodlozero Block (Karelia) were the provenance area from which these zircons were derived. The occurrence of the youngest zircons with age of 2654.3 ± 38.5 Ma is evidence that the formation of the Vetreny Belt, including the Toksha Formation, began no earlier than this time. Zircons from volcanic rocks of the Vetreny Belt yielded the age of 2405 ± 5 Ma. Thus, the age interval of the formation of the sedimentary-volcanogenic complex of the Vetreny Belt ranges from 2654.3 ± 38.5 to 2405 ± 5 Ma.

  1. Tectonic Evolution of an Early Precambrian High-Pressure Granulite Belt in the North China Craton

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A large-scale high-pressure granulite belt (HPGB), more than 700 km long, is recognized within the metamorphic basement of the North China craton. In the regional tectonic framework, the Hengshan-Chengde HPGB is located in the central collision belt between the western block and eastern block, and represents the deep crustal structural level. The typical high-pressure granulite (HPG) outcrops are distributed in the Hengshan and Chengde areas. HPGs commonly occur as mafic xenoliths within ductile shear zones, and underwent multipile deformations. To the south, the Hengshan-Chengde HPGB is juxtaposed with the Wutai greenstone belt by several strike-slip shear zones. Preliminary isotopic age dating indicates that HPGs from North China were mainly generated at the end of the Neoarchaean, assocaited with tectonic assembly of the western and esatern blocks.

  2. Belt attachment and system

    Science.gov (United States)

    Schneider, Abraham D.; Davidson, Erick M.

    2016-02-02

    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  3. The Glória quartz-monzodiorite: isotopic and chemical evidence of arc-related magmatism in the central part of the Paleoproterozoic Mineiro belt, Minas Gerais State, Brazil

    OpenAIRE

    Ciro A. Ávila; Wilson Teixeira; Umberto G. Cordani; Héctor R. Barrueto; Ronaldo M. Pereira; Veridiana T.S. Martins; Liu Dunyi

    2006-01-01

    The Glória quartz-monzodiorite, one of the mafic plutons of the Paleoproterozoic Mineiro belt, is intrusive into banded gneisses, amphibolites, schists and phyllites of the Rio das Mortes greenstone belt, in the southern portion of the São Francisco Craton, State of Minas Gerais, Brazil. The Glória quartz-monzodiorite yields a SHRIMP U-Pb zircon age of 2188 ± 29 Ma, suggesting a tectonic relationship with the pre-collisional phase of the Mineiro belt. According to the Nd isotopic evide...

  4. PGE, Re-Os, and Mo isotope systematics in Archean and early Proterozoic sedimentary systems as proxies for redox conditions of the early Earth

    Science.gov (United States)

    Siebert, C.; Kramers, J. D.; Meisel, Th.; Morel, Ph.; Nägler, Th. F.

    2005-04-01

    Re-Os data and PGE concentrations as well as Mo concentrations and isotope data are reported for suites of fine clastic sediments and black shales from the Barberton Greenstone Belt, South Africa (Fig Tree and Moodies Groups, 3.25-3.15 Ga), the Belingwe Greenstone Belt, Zimbabwe (Manjeri Formation, ca. 2.7 Ga) and shales from the Witwatersrand, Ventersdorp and Transvaal Supergroups, South Africa ranging from 2.95 to 2.2 Ga. Moderately oxidizing conditions are required to mobilize Re and Mo in the environment, Mo fractionation only occurs in solution, and these parameters thus have potential use as paleoredox proxies for the early Earth. PGE + Re abundance patterns of Barberton Greenstone Belt sediments are uniform and very similar in shape to those of komatiites. This indicates (1) that the PGE came from a source of predominantly ultramafic composition and, (2) that PGE were transported and deposited essentially in particulate form. Sediments from the younger Belingwe Greenstone Belt show more fractionated PGE + Re patterns and have Re/Os ratios 10 to 100× higher than those of Barberton sediments. Their PGE abundance patterns and Re/Os ratios are intermediate between those of the mid-Archean shales and Neoproterozoic to Recent black shales. They reflect scavenging of Re from solution in the sedimentary environment. δ 98/95Mo values of black shales of all ages correlate with their concentrations. The Barberton Greenstone Belt samples have ˜1-3 ppm Mo, similar to a granitoid-basaltic source. This Mo has δ 98/95Mo between -1.9 and -2.4‰ relative to present day mean ocean water molybdenum, MOMO and is thus not isotopically fractionated relative to such a source. Similar to the PGE this indicates transport in solid form. Sediments from the Belingwe Greenstone Belt show in part enhanced Mo concentrations (up to 6 ppm) and Mo isotope fractionation (δ 98/95Mo up to -1.4‰ relative to MOMO). The combined PGE + Re and Mo data show mainly reducing conditions in the

  5. Aspects of the Petrology and Geochemistry of Greenstones: with special reference to SW England and Wales

    Directory of Open Access Journals (Sweden)

    P.A. Floyd

    2009-09-01

    Full Text Available The use of texture, petrology and geochemistry of Neolithic greenstone hand axes, to determine provenance, is well established. However, as many UK greenstones are essentially meta-dolerites (mildly metamorphosed medium-grained basic rocks it is often necessary to consider the type and degree of alteration superimposed on the primary igneous mineralogy to establish different petrological groups of axes. In particular, alteration and texture can be highly variable in any one large outcrop that might have been used for the manufacture of axes. Similarly, geochemical fingerprinting of axes and subsequent comparison with known outcrops will only be successful if sufficient chemical data are available from any suspected source region when the full range of natural variation has been ascertained.

  6. GREENSTONE OPEN SOURCE DIGITAL LIBRARY SOFTWARE IN THE CONTEXT OF ARABIC CONTENT

    OpenAIRE

    Ramadan Elaiess

    2012-01-01

    The aim of this paper is to explore Greenstone open source digital library software which considered to be one of most essential open-source Content Management Systems (CMSs) that are available for use in creating, organizing, and managing Arabic content on the Internet. It focuses on the appropriateness of the system for Arabic content from different perspectives, such as its ability to support the Arabic language and to sustain and maintain different file formats. It also aims to examine Gr...

  7. Approche métallogénique du "Greenstone Belt" de Bogoin (RCA). Sa minéralisation en or

    OpenAIRE

    Biandja, Jean

    1988-01-01

    La minéralisation aurifère primaire du secteur de Bogoin se présente sous forme d'un stockwerk quartzeux de direction N-S encaissé dans des roches vertes. Ces dernières appartiennent à une série métamorphique (limite faciès schistes verts-amphibolite) plissée en un synclinorium de direction N-S qui dessine un "doigt de gant" dans un vaste massif granito-gneissique. La foliation principale (SP) est plan axial de cette structure. L'ensemble est réputé archéen. Le synclinal s'ennoie vers le Sud ...

  8. Rare earth chemistry of gold-bearing sedimentary carbonate horizons from the Abitibi Greenstone Belt, Ontario, Canada

    International Nuclear Information System (INIS)

    The ankerite, gold ore bodies of the Dome Mine, Timmins, Ontario are interflow units, 1 to 3 m thick in a sequence of tholeiitic basalts. The units consist of discontinuous layers of ferroan dolomite, chert and pyroclastic material, and laminations of iron sulfides, tourmaline, and graphite. They have been interpreted as sediments on the basis of their internal structure. Seven Rare Earth elements (REE) (Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb) were determined by instrumental neutron activation analysis, on 10 samples of carbonate material from the ankerite units. The chondrite normalized REE plots have relatively flat patterns with, in some cases, positive Europium anomalies. The flat patterns suggest that the fluids from which the carbonate precipitated was in equilibrium with volcanic rocks of tholeiitic and komatiitic composition. The positive Europium anomalies imply that the fluids were reducing at times. Such patterns are characteristic of Archaean sediments and also the precipitates associated with the discharge of hydrothermal solutions from vents on the East Pacific Rise

  9. Dynamic characteristics of conveyor belts

    Institute of Scientific and Technical Information of China (English)

    HOU You-fu; MENG Qing-rui

    2008-01-01

    The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and theological constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.

  10. An Archean Geomagnetic Reversal in the Kaap Valley Pluton, South Africa

    Science.gov (United States)

    Layer; Kroner; McWilliams

    1996-08-16

    The Kaap Valley pluton in South Africa is a tonalite intrusion associated with the Archean Barberton Greenstone Belt. Antipodal paleomagnetic directions determined from the central and marginal parts of the pluton record a geomagnetic reversal that occurred as the pluton cooled. The age of the reversal is constrained by an 40Ar/39Ar plateau age from hornblende at 3214 +/- 4 million years, making it the oldest known reversal. The data presented here suggest that Earth has had a reversing, perhaps dipolar, magnetic field since at least 3.2 billion years ago. PMID:8688075

  11. Belt-up!

    Energy Technology Data Exchange (ETDEWEB)

    Woof, M.

    1999-07-01

    Advanced control systems, improved materials and new dust control systems have turned the humble conveyor belt into a sophisticated method for transporting materials. RJB Mining has improved productivity at the Price of Wales colliery in Yorkshire, UK, with the installation of Alstom`s VDM drive system; Qualter Hall`s upgraded conveyor system at the Rugely Power Station in the UK is proving its ability to minimise coal spillage. The article highlights advances by several manufacturers in conveyor technology. 5 photos.

  12. Status report: working group on the controls of mineralization in granite-greenstone terraines of the Kaapvaal Craton

    International Nuclear Information System (INIS)

    This report summarize the activities of the working group on the controls of mineralization in Granite-Greenstone terraines of the Kaapvaal Craton. Some ore deposits in this granite-greenstone terraines have a strong affinity with those formed in modern ocean floor environments and others are associated with felsic volcanic rocks similar to those in modern island arc and Andean-type systems. Most of the deposits, however have been affected by tectonic and metamorphic processes leading to the formation of the craton. These craton forming processes have determined the present disposition of the ore bodies and have been responsible for concentrating elements such as Au and Sb into economically viable ore bodies

  13. Gold and uranium metallogenesis in the framework of Neo-proterozoic crust growth and differentiation: example of the Mayo-Kebbi Massif (Chad) in the Central Africa Orogenic belt

    International Nuclear Information System (INIS)

    The Mayo Kebbi massif located in southwestern Chad between the Congo craton in the South, the West African craton in the west and the Sahara meta-craton to the east exposes a segment of Neo-proterozoic juvenile crust accreted in the Central African orogenic belt during the Pan African orogeny. It consists of two greenstone belts (Zalbi and Goueygoudoum) separated by the May Kebbi calc-alkaline batholith complexes and intruded by calc-alkaline high-K granitic plutons. The whole is covered by Phanerozoic sedimentary formations. The greenstone belts contain sulphide zones hosted mainly by meta-plutonic rocks (granodiorites) and meta-basalts and meta-volcaniclastics. The mineralization comprises pyrite, pyrrhotite, arsenopyrite, chalcopyrite, pentlandite, pentlandite silver, pentlandite cobaltiferous, sphalerite, cobaltite. These sulphides are disseminated, aggregated in form of layers or are filling veins and cracks. The greenstones also contain quartz veins with calcite and chlorite comprising a mineralization made of pyrite, chalcopyrite, galena and gold. Gold is present both as native crystals and as electrum. The high-K calc-alkaline Zabili granitic pluton hosts uranium mineralization related to a superposition of: (1) ductile deformation and metasomatic alteration implying the interaction between magmatic minerals with a Na-rich fluid, of potential magmatic origin, coeval to the main deposition of uranium oxides, followed by (2) brittle deformation and deposition of secondary hydrated uranium silicates involving a Na-Ca-rich fluid. We propose that these uranium mineralizations represent the extreme expression of crustal differentiation as a result of Pan-African reworking of a Neo-proterozoic juvenile crustal segment. (author)

  14. Lap belt injuries in children.

    LENUS (Irish Health Repository)

    McGrath, N

    2010-07-01

    The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

  15. Belt conveyor for recycle aggregate

    OpenAIRE

    Bezrodný, Roman

    2014-01-01

    This bachelor thesis deals with the belt conveyor for the transport of recycled aggregate in an oblique direction. The aim is to find constructional solutions to the belt conveyor for the assigned transport capacity of 95 000 kg per hour, and the assigned axial distance of 49 m and different height of 12 m. The thesis contains a brief description of the belt conveyor and a description of basic constructional components. It also contains a functional calculation of the capacity and forces acco...

  16. SLH Timing Belt Powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  17. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  18. Chaos on the conveyor belt

    CERN Document Server

    Sándor, Bulcsú; Tél, Tamás; Néda, Zoltán

    2013-01-01

    The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by spring to an external static point, and due to the dragging effect of the belt the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can only be achieved by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic dynamics and phase transition-like behavior. Noise induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks, around five.

  19. Geochemical characteristics of gold bearing boninites and banded iron formations from Shimoga greenstone belt, India: Implications for gold genesis and hydrothermal processes in diverse tectonic settings

    Digital Repository Service at National Institute of Oceanography (India)

    Ganguly, S.; Manikyamba, C.; Saha, A.; Lingadevaru, M.; Santosh, M.; Rambabu, S.; Khelen, A.C.; Purushotham, D.; Linga, D.

    in an intraoceanic arc setting. The Gd/Yb and Dy/Yb ratios suggest parent magma origin through partial melting of a spinel lherzolite mantle source. Geochemical signatures of the boninites suggest high temperature, shallow level melting of refractory mantle wedge...

  20. Kuiper Belts Around Nearby Stars

    CERN Document Server

    Nilsson, R; Brandeker, A; Olofsson, G; Pilbratt, G L; Risacher, C; Rodmann, J; Augereau, J -C; Bergman, P; Eiroa, C; Fridlund, M; Thébault, P; White, G J

    2010-01-01

    In order to detect and characterise cold extended circumstellar dust originating from collisions of planetesimal bodies in disks, belts, or rings at Kuiper-Belt distances (30--50\\,AU or beyond) sensitive submillimetre observations are essential. Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied. // We have performed 870\\,$\\mu$m observations of 22 exo-Kuiper-Belt candidates, as part of a Large Programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870\\,$\\mu$m fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities $f_{\\mathrm{dust}}$, dust temperatures...

  1. Origin of Archean Chromitites in the Nuggihalli Schist Belt, Dharwar Craton (India)

    Science.gov (United States)

    Mukherjee, R.; Mondal, S. K.; Rosing, M. T.; Frei, R.

    2009-12-01

    Layered ultramafic-mafic rocks with chromitite bodies occur as sill-like intrusions within the Archean greenstone sequences of the Nuggihalli belt, Western Dharwar Craton. The 3.1Ga chromitite-bearing ultramafic-mafic rocks occur as dismembered en echelon, lenticular units that are conformable within the metasedimentary rocks, and surrounded by the tonalite-trondhjemite-granodiorite suite. The chromitite bodies are hosted within intensely deformed serpentinite, and associated with gabbro. The chromitite bodies have high length/width ratio (60-500 m/15 m) and occur in the form of pods and elongated lenses. Detailed electron microprobe study reveals high Cr/(Cr+Al)=0.85-0.86 and moderate Mg/(Mg+Fe2+)=0.38-0.58 of the primary chromite from the massive chromitite. Interstitial and included olivine and pyroxene grains within massive chromitite, exhibit very high Fo content (Fo96-98) and Mg-numbers (94-99) respectively. Chromite grains exhibit intense compositional variability due to subsolidus re-equilibration and low temperature hydrothermal alteration processes such as in the altered massive chromitite (70% chromite), serpentinite (2% chromite) and silicate-rich chromitite (45% chromite). In these associations, chromite grains are compositionally zoned and commonly altered to ferritchromit (rarely magnetite) along the rim and fractures. The primary chromite compositions are used to compute the parent melt that is characterised by low Al2O3 (8.38-10.63 wt%), moderate to high TiO2 (0.94-1.58 wt%) and FeO/MgO ratios of 0.46-0.92 wt%. The parent melt calculations indicate derivation from a high-Mg komatiitic basalt, and matches with the compositions of komatiitic rocks reported from the greenstone terrain. Parent melts are produced by high degrees of partial melting of a depleted source mantle evident from the refractory compositions of chromite, olivine and pyroxene. Tectonic discrimination diagrams indicate a supra-subduction zone setting (SSZ) for the Archean

  2. French experience in seat belt use.

    NARCIS (Netherlands)

    Lassarre, S. & Page, Y.

    1992-01-01

    This paper concerns the French experience in seat belt use. As well as the seat belt regulations, the strategies employed to reinforce the wearing of seat belts by using information and encouragement campaigns and checks by the police and gendarmerie are described here along with their timetables an

  3. Study of thermal conditions at belt slippage

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, R.; Pampel, W.; Pfleger, P.

    1987-04-01

    Conveyor belt slippage experiments are carried out on the Chrudim (Czechoslovakia) industrial sized test stand for belt widths up to 1 m and driving drum forces up to 400 kW. The stand is operated jointly by TAKRAF (GDR) and VITKOVICE VUTZ, Prague. From 1972 to 1981, 7 belt conveyor fires occurred in GDR brown coal surface mines due to belt slippage. One of these cases led to a belt fire after only 15 s at 100% belt slippage. Aim of the study was to determine accurate permissible slippage values. Design of the test stand is explained as well as test procedures with belt slippage at the driving drum varying between 10 and 100%. Belt driving parameters were measured along with temperature of the drum surface. The heat penetration parameter b (in kJ/m/sup 2/) was calculated. Maximum temperatures up to 150 C were measured on the drum during partial slippage and 370 C at 100% belt slippage. The ignition temperature of rubber abrasion fines was also analyzed and found to vary between 40 and 318 C, i.e. substantially lower than belt and drum layer ignition temperatures. Graphs and diagram of slippage measurement results are calculated. Values for permissible maximum slippage time for operating belt slippage monitoring devices are shown. These devices are required to be installed in the GDR at heavy mine belt conveyors with driving forces exceeding 500 kW. 8 refs.

  4. Depositional process for the Triassic-Jurassic stratiform manganese deposits in the Chichibu Belt, Southwest Japan.

    Science.gov (United States)

    Tomimatsu, Y.; Onoue, T.

    2015-12-01

    The chert-hosted manganese deposits have been known to occur in the Triassic to Jurassic chert or chert-greenstone complex within a Jurassic accretionary complex in Japan. In order to reveal the origin of these manganese deposits, we investigated the stratigraphy, age and geochemistry of manganese deposits from the Triassic to Jurassic bedded chert succession of the Chichibu Belt, defined as a Jurassic subduction-generated accretionary complex in Southwest Japan. The Triassic to Jurassic bedded cherts in the Chichibu Belt are considered to be deep-sea sediments that accumulated in an open-ocean realm of the Panthalassa Ocean. Our biostratigraphic analysis of radiolarians reveals that the stratiform manganese deposits intercalated in the bedded cherts were deposited in the Late Triassic and Early Jurassic. Upper Triassic manganese deposit occurs associated with the massive cherts which appear to have been formed by hydrothermal activity. The red bedded chert above the manganese deposit yields radiolarian fossils, including Trialatus longicornutus and Poulpus carcharus. These radiolarians indicate that age of manganese deposits can be correlated with the late Carnian age. Lower Jurassic manganese deposit occurs intercalated within the gray to dark gray bedded cherts. Detailed biostratigraphic analysis of radiolarians reveals that manganese deposit is embedded in the upper Pliensbachian to Toarcian (Trillus elkhornensis Zone). Chemical compositions of Upper Triassic deposits are characterized by enrichments in Mn and depletion of Co, Ni and Zn. These geochemical features are similar to those of modern submarine hydrothermal manganese deposits from hydrothermal activity. In contrast, lower Jurassic manganese deposits were triggered by an influx of warm, saline and oxic water into a stagnant deep ocean floor basin. It is likely that the deposits are considered to have formed by oceanic anoxic event.

  5. Ocorrência de rochas da fácies granulito no Cinturão Mineiro, Minas Gerais, Brasil Occurrence of granulite-facies rocks in the Mineiro Belt, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Newton Souza Gomes

    2010-09-01

    Full Text Available Na região de Lagoa Dourada, inserida no Cinturão Mineiro, ocorrem granitóides paleoproterozóicos, que intrudem seqüências supracrustais arqueanas do greenstone belt Rio das Velhas. Os granitóides são cortados por rochas máficas anfibolitizadas, que portam xenólitos de granulitos. Trata-se de granulitos máficos caracterizados pela textura granoblástica e pela paragênese ortopiroxênio-clinopiroxênio-anfibólio-plagioclásio. Como fases secundárias, registram-se actinolita, cummingtonita, carbonato, epídoto, granada e quartzo. Determinações geotermométricas baseadas nos pares minerais ortopiroxênio-clinopiroxênio e anfibólio-plagioclásio produziram valores de temperatura entre 700 e 853ºC. As fases secundárias são produtos de um processo metamórfi co posterior.Paleoproterozoic granitoids intruding the Archean greenstone belt of Rio das Velhas are found in the region of Lagoa Dourada, which belongs to the Mineiro Belt. The granitoids are cut by amphibolitized mafi c rocks which contain xenoliths of granulite facies rocks. The rocks are mafi c granulites, characterized by their granoblastic texture and by parageneses orthopyroxene-clinopyroxene-amphibole-plagioclase. As secondary minerals, actinolite, carbonate, epidote, cummingtonite, garnet and quartz can be found. Geothermometric determinations based on the mineral pairs orthopyroxene-clinopyroxene and amphibole-plagioclase yielded temperature values between 700ºC and 853ºC. The secondary mineral phases are interpreted as a result of a younger metamorphic event.

  6. The Wisconsin magmatic terrane: An Early Proterozoic greenstone-granite terrane formed by plate tectonic processes

    Science.gov (United States)

    Schulz, K. J.; Laberge, G. L.

    1986-01-01

    The Wisconsin magmatic terrane (WMT) is an east trending belt of dominantly volcanic-plutonic complexes of Early Proterozoic age (approx. 1850 m.y.) that lies to the south of the Archean rocks and Early Proterozoic epicratonic sequence (Marquette Range Supergroup) in Michigan. It is separated from the epicratonic Marquette Range Supergroup by the high-angle Niagara fault, is bounded on the south, in central Wisconsin, by Archean gneisses, is truncated on the west by rocks of the Midcontinent rift system, and is intruded on the east by the post-orogenic Wolf river batholith. The overall lithologic, geochemical, metallogenic, metamorphic, and deformational characteristics of the WMT are similar to those observed in recent volcanic arc terranes formed at sites of plate convergence. It is concluded that the WMT represents an evolved oceanic island-arc terrane accreated to the Superior craton in the Early Proterozoic. This conclusion is strengthened by the apparent absence of Archean basement from most of the WMT, and the recent recognition of the passive margin character of the epicratonic Marquette Range Supergroup.

  7. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  8. NONLINEAR DYNAMIC BEHAVIOR OF VISCOELATIC TRANSMISSION BELT

    Institute of Scientific and Technical Information of China (English)

    Li Yinghui; Gao Qing; Jian Kailin; Yin Xuegang

    2003-01-01

    The nonlinear dynamic responses of viscoelastic axially transmission belts are investigated and the Kelvin viscoelastic differential constitutive model is employed to characterize the material property of belts. The generalized equation of motion is obtained for a viscoelatic axially transmission belts with geometric nonlinearity first, and then is reduced to be a set of second-order nonlinear ordinary differential equations by applying Galerkin's method. Finally, the effects of viscosity parameter and elastic parameter and the moving velocity of the belts on the transient responses are investigated by the research of digital simulation.

  9. Apparatus for heat treating plastic belts

    Science.gov (United States)

    Topits, A., Jr.

    1975-01-01

    Apparatus performs programed rotating, stretching/shrinking and heat treatment necessary to fabrication of high-performance plastic belts. Belts can be treated in lengths varying from 7 to 48 in., in widths up to 1 in., and in thicknesses up to approximately 0.003 in.

  10. Understanding Quaternions and the Dirac Belt Trick

    Science.gov (United States)

    Staley, Mark

    2010-01-01

    The Dirac belt trick is often employed in physics classrooms to show that a 2n rotation is not topologically equivalent to the absence of rotation whereas a 4n rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors…

  11. Parameters affecting seat belt use in Greece.

    Science.gov (United States)

    Yannis, G; Laiou, A; Vardaki, S; Papadimitriou, E; Dragomanovits, A; Kanellaidis, G

    2011-09-01

    The objective of this research is the exploration of seat belt use in Greece and particularly the identification of the parameters affecting seat belt use in Greece. A national field survey was conducted for the analytical recording of seat belt use. A binary logistic regression model was developed, and the impact of each parameter on seat belt use in Greece was quantified. Parameters included in the model concern characteristics of car occupants (gender, age and position in the car), the type of the car and the type of the road network. The data collection revealed that in Greece, the non-use of seat belt on the urban road network was higher than on the national and rural road network and young and older men use seat belts the least. The developed model showed that travelling on a national road is negative for not wearing the seat belt. Finally, the variable with the highest impact on not wearing a seat belt is being a passenger on the back seats. PMID:21452095

  12. Radiation belt dynamics during solar minimum

    Energy Technology Data Exchange (ETDEWEB)

    Gussenhoven, M.S.; Mullen, E.G. (Geophysics Lab., Air Force Systems Command, Hanscom AFB, MA (US)); Holeman, E. (Physics Dept., Boston College, Chestnut Hill, MA (US))

    1989-12-01

    Two types of temporal variation in the radiation belts are studied using low altitude data taken onboard the DMSP F7 satellite: those associated with the solar cycle and those associated with large magnetic storm effects. Over a three-year period from 1984 to 1987 and encompassing solar minimum, the protons in the heart of the inner belt increased at a rate of approximately 6% per year. Over the same period, outer zone electron enhancements declined both in number and peak intensity. During the large magnetic storm of February 1986, following the period of peak ring current intensity, a second proton belt with energies up to 50 MeV was found at magnetic latitudes between 45{degrees} and 55{degrees}. The belt lasted for more than 100 days. The slot region between the inner and outer electron belts collapsed by the merging of the two populations and did not reform for 40 days.

  13. The Gould's Belt distance survey

    CERN Document Server

    Loinard, L; Torres, R M; Dzib, S; Rodriguez, L F; Boden, A F

    2011-01-01

    Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object within 500 pc of the Sun to better than a few percent. Because they are magnetically active, young stars are often associated with compact radio emission detectable using VLBI techniques. Here we will show how VLBI observations have already constrained the distance to the most often studied nearby regions of star-formation (Taurus, Ophiuchus, Orion, etc.) and have started to provide information on their internal structure and kinematics. We will then briefly describe a large project (called The Gould's Belt Distance Survey) designed to provide a detailed view of star-formation in the Solar neighborhood using VLBI observations.

  14. Binaries in the Kuiper Belt

    CERN Document Server

    Noll, K S; Chiang, E I; Margot, J L; Kern, S D; Noll, Keith S.; Grundy, William M.; Chiang, Eugene I.; Margot, Jean-Luc; Kern, Susan D.

    2007-01-01

    Binaries have played a crucial role many times in the history of modern astronomy and are doing so again in the rapidly evolving exploration of the Kuiper Belt. The large fraction of transneptunian objects that are binary or multiple, 48 such systems are now known, has been an unanticipated windfall. Separations and relative magnitudes measured in discovery images give important information on the statistical properties of the binary population that can be related to competing models of binary formation. Orbits, derived for 13 systems, provide a determination of the system mass. Masses can be used to derive densities and albedos when an independent size measurement is available. Angular momenta and relative sizes of the majority of binaries are consistent with formation by dynamical capture. The small satellites of the largest transneptunian objects, in contrast, are more likely formed from collisions. Correlations of the fraction of binaries with different dynamical populations or with other physical variabl...

  15. Strategy for replacing conveyor belts in complex haulage systems

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, L.; Jurdziak, L.; Masella, J.

    1986-01-01

    Discusses service life and reliability of conveyor belts used for mine haulage in brown coal surface mining and a method for optimizing belt service life. Based on analysis of operation of 900-1,200 m long belt conveyors in the Konin surface mine, failure rates and factors that influence belt reliability were determined. Effects of joints, length of belt sections and service life of each belt section were analyzed. Formulae for determining the optimum time interval for replacing belt sections on a long belt conveyor were derived. The formulae consider cost of new belt sections, replacement cost and haulage losses associated with possible belt failure caused by excessive belt service life. The optimization procedure has been successfully tested at the Turow surface mine and power plant. 4 refs.

  16. Seat belt use law in developing countries

    Institute of Scientific and Technical Information of China (English)

    SangWanLee

    1999-01-01

    Objective:To highlight the way to successful implementation of mandantory seat belt use law in developing countries particulary where have significant increase in number or cars and subsequent increase in car occupant casualties.Methods:Literatures concerning seat belt use were reviewed and experiences of the world.Satisfactory or not,investigated.It summed up general aspects of seat belt use as well as benefits,attitude toward legislation and measures to enhance the usage.Results:Seat belt use has been proven and stood time tested as the most effective means to protect car occupants from road crash injuries.It appears to be arduous to achieve the golal of seat belt use law in developing countries. but possible via strategies appropriately leading to legislation and promotion of the belt usage.Conclusions:It is prime necessity for the government authorities to recognize the importance of seat belt use.There needs an organizational structure composed of relevant professional from both private and government sectors which is able to carry out every steps toward successful legislation and implementation:education,publicity,enforcement,evaluation and dissemination of the law's benefits.

  17. DYNAMIC RESPONSES OF VISCOELASTIC AXIALLY MOVING BELT

    Institute of Scientific and Technical Information of China (English)

    李映辉; 高庆; 蹇开林; 殷学纲

    2003-01-01

    Based on the Kelvin viscoelastic differential constitutive law and the motion equation of the axially moving belt, the nonlinear dynamic model of the viscoelastic axial moving belt was established. And then it was reduced to be a linear differential system which the analytical solutions with a constant transport velocity and with a harmonically varying transport velocity were obtained by applying Lie group transformations. According to the nonlinear dynamic model, the effects of material parameters and the steady-state velocity and the perturbed axial velocity of the belt on the dynamic responses of the belts were investigated by the research of digital simulation. The result shows: 1 ) The nonlinear vibration frequency of the belt will become small when the relocity of the belt increases. 2 ) Increasing the value of viscosity or decreasing the value of elasticity leads to a deceasing in vibration frequencies. 3 ) The most effects of the transverse amplitudes come from the frequency of the perturbed velocity when the belt moves with harmonic velocity.

  18. Computer-aided design of conveyor belts

    Energy Technology Data Exchange (ETDEWEB)

    Karolewski, B.; Pytel, J.

    1984-01-01

    Possibilities are discussed for using mathematical models of belt conveyors for development of computer-aided design of conveyors for coal mining. Examples of optimization tasks and methods for their solution using computerized simulation are analyzed. The analysis is illustrated by an algorithm used to design a starter for the drive system of a belt conveyor. Electromagnetic moment and starting current are used as optimization criteria. A simplified model of a belt conveyor is used. The model consists of an equation of motion with variable braking moment and variable moment of inertia. 3 references.

  19. Cooling age of the Birimian juvenile crust in West Africa. U-Pb, Rb-Sr and K-Ar data on the 2. 1 Ga granite-greenstone terrains from SW-Niger. Age de refroidissement de la croute juvenile birimienne d'Afrique de l'Ouest. Donnees U-Pb, Rb-Sr et K-Ar sur les formations a 2. 1 Ga du SW-Niger

    Energy Technology Data Exchange (ETDEWEB)

    Lama, C.; Dautel, D.; Zimmermann, J.L. (Centre National de la Recherche Scientifique (CNRS), 54 - Nancy (France). Centre de Recherches Petrographiques et Geochimiques); Barbey, P. (Nancy-1 Univ., 54 (France)); Cheilletz, A. (Centre National de la Recherche Scientifique (CNRS), 54 - Nancy (France). Centre de Recherches Petrographiques et Geochimiques Ecole Nationale Superieure de Geologie Appliquee et de Prospection Miniere, 54 - Nancy (France)); Pons, J. (Orleans Univ., 45 (France))

    1994-08-18

    A comparison between zircon U-Pb, whole-rock Rb-Sr and biotite-amphibole K-Ar data on Birimian granite-greenstone terrains from SW-Niger indicates that the youngest granitic plutons were emplaced at 2.115 [+-] 5 Ma and that both the plutons and the surrounding greenstones yield cooling ages around 2.118 Ma. The age similarity between the end of the plutonism and the cooling of plutons and surrounding greenstone further suggests rapid cooling at the end of the plutonic event and, thus, corroborates a model of greenstone metamorphism linked to the thermal effect of the plutons. (authors).

  20. From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives: influence of tensioner and belt characteristics

    OpenAIRE

    Manin, Lionel; Michon, Guilhem; Rémond, Didier; Dufour, Regis

    2007-01-01

    Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip: dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been u...

  1. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  2. Handbook Timing Belts Principles, Calculations, Applications

    CERN Document Server

    Perneder, Raimund

    2012-01-01

    Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

  3. Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, T. [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

  4. Two Discrete UHP and HP Metamorphic Belts in the Central Orogenic Belt, China

    Institute of Scientific and Technical Information of China (English)

    Suo Shutian; Zhong Zengqiu; Zhang Li; Zhou Hanwen; You Zhendong

    2006-01-01

    An attempt is made to confirm the existence of the two discrete UHP and HP metamorphic belts in the central orogenic belt in China. Detailed geological mapping and structural and petrological analyses of the Kanfenggou (看丰沟) and Xiangfanggou ( 香坊沟 ) slices exposed in the eastern Qinling (秦岭) orogen indicate that they experienced ultrahigh pressure and high pressure metamorphism, respectively. The former, situated in northern Qinling, contains a large volume of fine-grained coesite and quartz pseudomorphs after coesite- and microdiamond-bearing eclogite lenses, whereas the latter, located in southern Qinling, preserves the relicts of a high pressure metamorphic mineral assemblage. Based on extensive fieldwork together with compilations at the scale of the orogenic belt, and a comparison of Pb isotopic compositions between the UHP metamorphic rocks from Kanfenggou slice and the Dabie UHP metamorphic belt, we propose that there are at least two discrete ultrahigh pressure metamorphic belts with different ages and tectonic evolution within the central orogenic belt in China. The first is the South Altun-North Qaidam-North Qinling ultrahigh pressure metamorphic belt of Early Paleozoic age (~ 500-400 Ma). The Kanfenggou ultrahigh pressure slab is located at its eastern segment. The second is the well constrained Dabie ( 大别 )-Sulu ( 苏鲁 ) ultrahigh/ high pressure metamorphic belt of Triassic age (~250-220 Ma). The Xiangfanggou high pressure metamorphic slab is a westward extension of the Dabie-Sulu ultrahigh/high pressure metamorphic belt. The Pb isotopic compositions of the UHP metamorphic rocks from Kanfenggou UHP fragment in East Qinling are different from those of the UHP rocks in Dabie UHP metamorphic belt, but are consistent with those of the rocks from the Qinling rock group and Erlangping (二郎坪) rock group. The East Qinling UHP metamorphic belt does not appear to link with the Dabie-Sulu UHP metamorphic belt. These two ultrahigh

  5. Microscale mapping of alteration conditions and potential biosignatures in basaltic-ultramafic rocks on early Earth and beyond.

    Science.gov (United States)

    Grosch, Eugene G; McLoughlin, Nicola; Lanari, Pierre; Erambert, Muriel; Vidal, Olivier

    2014-03-01

    Subseafloor environments preserved in Archean greenstone belts provide an analogue for investigating potential subsurface habitats on Mars. The c. 3.5-3.4 Ga pillow lava metabasalts of the mid-Archean Barberton greenstone belt, South Africa, have been argued to contain the earliest evidence for microbial subseafloor life. This includes candidate trace fossils in the form of titanite microtextures, and sulfur isotopic signatures of pyrite preserved in metabasaltic glass of the c. 3.472 Ga Hooggenoeg Formation. It has been contended that similar microtextures in altered martian basalts may represent potential extraterrestrial biosignatures of microbe-fluid-rock interaction. But despite numerous studies describing these putative early traces of life, a detailed metamorphic characterization of the microtextures and their host alteration conditions in the ancient pillow lava metabasites is lacking. Here, we present a new nondestructive technique with which to study the in situ metamorphic alteration conditions associated with potential biosignatures in mafic-ultramafic rocks of the Hooggenoeg Formation. Our approach combines quantitative microscale compositional mapping by electron microprobe with inverse thermodynamic modeling to derive low-temperature chlorite crystallization conditions. We found that the titanite microtextures formed under subgreenschist to greenschist facies conditions. Two chlorite temperature groups were identified in the maps surrounding the titanite microtextures and record peak metamorphic conditions at 315 ± 40°C (XFe3+(chlorite) = 25-34%) and lower-temperature chlorite veins/microdomains at T = 210 ± 40°C (lower XFe3+(chlorite) = 40-45%). These results provide the first metamorphic constraints in textural context on the Barberton titanite microtextures and thereby improve our understanding of the local preservation conditions of these potential biosignatures. We suggest that this approach may prove to be an important tool in future

  6. Seat belts, airbags and child protection devices. [previously: Seat belts and child restraint seats.

    NARCIS (Netherlands)

    2010-01-01

    In the Netherlands, the use of seat belts results in a yearly reduction of hundreds of fatalities. Seat belts reduce the risk of fatal injury by 37 to 48%, depending on the position in the car. At 50%, the effect of child protection devices is even slightly higher. When last measured (in 2010), 97%

  7. Analysis of stress distribution of timing belts by FEM; Yugen yosoho ni yoru timing belt oryoku kaiseki (belt code oryoku bunpu kaiseki hokoku)

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Y.; Tomono, K.; Takahashi, H.; Uchida, T. [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    A model of the belt analyzed by-ABAQUS (: a general nonlinear finite element program) successfully confirmed the mechanism that generates the belt cord stress. A quite good agreement between experimental and computed results for the stress distribution of the belt cord. It is found that maximum stress of the cords occurs near the root of the tooth by calculation, where the belt cords break off. 3 refs., 9 figs.

  8. Flat belt continuously variable high speed drive

    Energy Technology Data Exchange (ETDEWEB)

    Kumm, E.L.

    1992-02-01

    A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley turbine'' (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the turbine'' corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the turbine'' belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.

  9. Geochemical Evidence for Subduction in the Early Archaean from Quartz-Carbonate-Fuchsite Mineralization, Isua Supracrustal Belt, West Greenland

    Science.gov (United States)

    Pope, E. C.; Rosing, M. T.; Bird, D. K.

    2011-12-01

    Quartz, carbonate and fuchsite (chromian muscovite) is a common metasomatic assemblage observed in orogenic gold systems, both in Phanerozoic convergent margin settings, and within supracrustal and greenstone belts of Precambrian rocks. Geologic and geochemical observations in younger orogenic systems suggest that ore-forming metasomatic fluids are derived from subduction-related devolitilization reactions, implying that orogenic Au-deposits in Archaean and Proterozoic supracrustal rock suites are related to subduction-style plate tectonics beginning early in Earth history. Justification of this metasomatic-tectonic relationship requires that 1) Phanerozoic orogenic Au-deposits form in subduction-zone environments, and 2) the geochemical similarity of Precambrian orogenic deposits to their younger counterparts is the result of having the same petro-genetic origin. Hydrogen and oxygen isotope compositions of fuchsite and quartz from auriferous mineralization in the ca. 3.8 Ga Isua Supracrustal Belt (ISB) in West Greenland, in conjunction with elevated concentrations of CO2, Cr, Al, K and silica relative to protolith assemblages, suggest that this mineralization shares a common petro-tectonic origin with Phanerozoic orogenic deposits and that this type of metasomatism is a unique result of subduction-related processes. Fuchsite from the ISB has a δ18O and δD of +7.7 to +17.9% and -115 to -61%, respectively. δ18O of quartz from the same rocks is between +10.3 and +18.6%. Muscovite-quartz oxygen isotope thermometry indicates that the mineralization occurred at 560 ± 90oC, from fluids with a δD of -73 to -49% and δ18O of +8.8 to +17.2%. Calculation of isotopic fractionation during fluid-rock reactions along hypothetical fluid pathways demonstrates that these values, as well as those in younger orogenic deposits, are the result of seawater-derived fluids liberated from subducting lithosphere interacting with ultramafic rocks in the mantle wedge and lower crust

  10. The Compositions of Kuiper Belt Objects

    CERN Document Server

    Brown, Michael E

    2011-01-01

    Objects in the Kuiper belt are small and far away thus difficult to study in detail even with the best telescopes available at earth. For much of the early history of the Kuiper belt, studies of the compositions of these objects were relegated to collections of moderate quality spectral and photometric data that remained difficult to interpret. Much early effort was put into simple correlations of surface colors and identifications of spectral features, but it was difficult to connect the observations to a larger understanding of the region. The last decade, however, has seen a blossoming in our understanding of the compositions of objects in the Kuiper belt. This blossoming is a product of the discoveries of larger -- and thus easier to study -- objects, continued dedication to the collection of a now quite large collection of high quality photometric and spectroscopic observations, and continued work at the laboratory and theoretical level. Today we now know of many processes which affect the surface compos...

  11. Perceptual findings on the broadway belt voice.

    Science.gov (United States)

    DeLeo LeBorgne, Wendy; Lee, Linda; Stemple, Joseph C; Bush, Heather

    2010-11-01

    The present study required raters (casting directors) to evaluate the belt voice quality of 20 musical theater majors who were proficient in the singing style referred to as belting. Two specified vocalizes and six short excerpts from the belting repertoire were used for rating purposes. The raters were asked to judge the belters on a set of seven perceptual parameters (loudness, vibrato, ring, timbre, focus, nasality, and registration breaks), and then report an overall score for these student belters. The four highest and lowest average scores were used to establish the elite and average student belters. A correlation analysis and linear regression analysis provided insight regarding which perceptual judgments correlated most highly with the elite and average scores. The present study found the perceptual ratings of vibrato and ring to be most highly correlated to the elite student belter. In addition, vibrato and ring were found to highly correlate with perceived loudness. PMID:19900789

  12. Composite Microdiscs with a Magnetic Belt

    DEFF Research Database (Denmark)

    Knaapila, Matti; Høyer, Henrik; Helgesen, Geir

    2015-01-01

    We describe an emulsion-based preparation of patchy composite particles (diameter of 100-500 mu m) consisting of a disclike epoxy core and a belt of porous polystyrene particles (diameter of 30 mu m) with magnetite within the pores. Compared to the magnetically uniform polystyrene particles......, the spontaneous aggregation of composite particles is suppressed when dispersed into liquid, which is attributed to the increased particle size, reduced magnetic susceptibility, and the shape of the magnetic domain distribution within the particles (spherical versus a belt). When the composite particles...

  13. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  14. Design aspects of multiple driven belt conveyors

    NARCIS (Netherlands)

    Nuttall, A.J.G.

    2007-01-01

    Worldwide belt conveyors are used to transport a great variety of bulk solid materials. The desire to carry higher tonnages over longer distances and more diverse routes, while keeping exploitation costs as low as possible, has fuelled many technological advances. An interesting development in the r

  15. Imaging Jupiter Radiation Belts At Low Frequencies

    Science.gov (United States)

    Girard, J. N.; de Pater, I.; Zarka, P.; Santos-Costa, D.; Sault, R.; Hess, S.; Cecconi, B.; Fender, R.; Pewg, Lofar

    2014-04-01

    The ultra-relativistic electrons, trapped in the inner radiation belts of Jupiter, generates a strong synchrotron radio emission (historically known as the jovian decimeter radiation (DIM)) which is beamed, polarized (~20% linear, ~1% circular) and broadband. It has been extensively observed by radio telescopes/ probes and imaged by radio interferometers over a wide frequency spectrum (from >300 MHz up to 22 GHz). This extended emission presents two main emission peaks constantly located on both sides of the planet close to the magnetic plane. High latitude emissions were also regularly observed at particular frequencies, times and in particular observational configurations. This region of the magnetosphere is "frozen" due to the strong magnetic field (~4.2 G as the equator) and therefore is forced to rotate at the planetary period (T≈9h55m). Due to the tilt (~ 10o) between the spin axis of the planet and the magnetic axis (which can be seen as dipolar in first approximation), the belts and the associated radio emission wobble around the planet center. The analysis of the flux at different frequencies highlighted spatial, temporal and spectral variabilities which origins are now partly understood. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility effect (wobbling, beaming, position of the observer in the magnetic rotating reference frame) [1], [2] and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) [3], [4], [5]. A complete framework is necessary to fully understand the source, loss and transport processes of the electrons originating from outside the belt, migrating by inward diffusion and populating the inner region of the magnetosphere. Only a few and unresolved measurements were made below 300 MHz and the nonsystematic observation of this radio emission

  16. Geochemistry of the Halogens (I, Br, Cl) and Evolution of the Seawater During the Archean

    Science.gov (United States)

    Avice, G.; Marty, B.; Burgess, R.; Goldsmith, S. L.

    2015-12-01

    Halogens (I, Cl, Br) on Earth are depleted relative to the results of the condensation sequence of elements from the solar nebula [1]. The cause of this depletion remains unknown but might be related to loss from impacts or to the presence of an hidden reservoir (e.g. core). The presence of fluid inclusions in hydrothermal quartz of various ages is an opportunity to follow the evolution of the composition of the atmosphere (N, noble gases) through time [2] but also of halogens in seawater (their main reservoir). Such studies may help to constrain what is the origin of these volatile elements on Earth. For this purpose, we analysed quartz from hydrothermal veins and pods of various localities and ages (e.g. Barberton Greenstone Belt (South Africa; 3.2 Ga), Fortescue Group (Australia; 2.7 Ga)) by crushing and step-heating following the extended Ar-Ar method [3]. In Barberton and Fortescue Gp. quartz, a hydrothermal component characterized by excess 40Ar (40ArE) and closely associated with chlorine is clearly identified from crushing and step-heating results and permits to define a 40ArE/Cl used to correct Ar-Ar data for this contribution. In the case of Barberton, the correction for the hydrothermal component leads to an approximate formation age of the quartz of 3.2 (+/- 0.1) Ga. In Barberton quartz, halogens elemental ratios obtained during crushing and step-heating experiments are highly enriched in iodine and bromine (I/Cl=2-7x10-4; Br/Cl=4-10x10-3) relative to modern seawater. These results are similar to those found in a previous study of Barberton fluid inclusions [3] and can be interpreted as indicators that organic carbon was not sufficiently abundant at this time and/or this location to efficiently pump Br and I during sediment burial. Iodine and bromine, in Fortescue Gp. quartz, are less enriched suggesting that, in that case, organic activity already acted as pump for these elements. [1] Sharp & Draper (2013) EPSL, 369-370, p. 71-77 [2] Pujol et al. (2011

  17. Detecting Extrasolar Asteroid Belts Through Their Microlensing Signatures

    CERN Document Server

    Lake, Ethan; Dong, Subo

    2016-01-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called "pseudo-caustics", regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive microlensing light curves across a wide region of belt parameter space and possess remarkably large lensing cross-sections. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys (e.g., WFIRST) may be able to discover extrasolar asteroid belts with masses of the order of $0.1 M_{\\oplus}$.

  18. Seat Belt Use Among Adult Workers - 21 States, 2013.

    Science.gov (United States)

    Boal, Winifred L; Li, Jia; Rodriguez-Acosta, Rosa L

    2016-01-01

    Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use. PMID:27309488

  19. LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

    Institute of Scientific and Technical Information of China (English)

    薛河; 苏清祖; 马胜利

    1999-01-01

    The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are'systematically analyzed and some computing formulas derived, by these formulas, the actual load distribution onthe two drums of rigid connected or separately driving belt conveyor can be separately calculated. These formulas also can be as the theory base for adjusting the driving force of two drums.

  20. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  1. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2006-08-01

    Full Text Available High altitude nuclear explosions (HANEs and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR. Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  2. Araguaia fold belt, new geochronological data

    International Nuclear Information System (INIS)

    The northern part of the Araguaia Fold Belt (AFB) outcrops in a N-S direction for about 400 km in the state of Tocantins. Dome-like structures occur in this fold belt also in a N-S direction. Both deformation and metamorphism increase from the West to the East. The basement of the AFB consist of Colmeia complex and Cantao gneiss, which crop out mainly in the core of the dome-like structures. The supracrustals rocks of the fold belt belongs to the Baixo Araguaia supergroup which is divided into the lower Estrondo group and the upper Tocantins group. Preliminary Sm-Nd data from the Colmeia complex (Grota Rica dome) gave Archean model ages of 2.8 Ga (TNd sub(DM)) while Rb-Sr data in the same rocks give an age of 2530 ± 200 Ma. In the others dome-like structures, the Rb-Sr systematics gave ages for the Colmeia a complex of 2239 ± 47 Ma (Colmeia structure) and 1972 ± 46 Ma (Lontra structure). These younger ages are believed to represent partial to total isotopic resetting of the Rb-Sr system during the Transamazonian Event. The Rb-Sr studies of the Cantao gneiss gave an age of 1774 ± 31 Ma. (author)

  3. Metamorphic fluid flow in the northeastern part of the 3.8-3.7 Ga Isua Greenstone Belt (SW Greenland): A re-evalution of fluid inclusion evidence for early Archean seafloor-hydrothermal systems

    DEFF Research Database (Denmark)

    Heijlen, Wouter; Appel, P. W. U.; Frezzotti, M. L.;

    2006-01-01

    . In most quartz crystals, however, recrystallization obliterated such early fluid inclusion assemblages and left graphite and carbonate as solid inclusions in recrystallized grains. Intragranular fluid inclusion trails in the recrystallized grains of breccia cementing and crosscutting quartz veins have CO2...... segregations showed that they were affected by variable recrystallization which controlled their fluid inclusion content. The oldest unaltered fluid inclusions found are present in vein crystals that survived dynamic and static recrystallization. These crystals contain a cogenetic, immiscible assemblage of CO2......-rich (+H2O, +graphite) and brine-rich (+CO2, +halite, +carbonate) inclusions. The gas-rich inclusions have molar volumes between 44.8 and 47.5 cm(3)/Mol, while the brine inclusions have a salinity of similar to 33 eq. wt% NaCl. Modeling equilibrium immiscibility using volumetric and compositional...

  4. Seat belt use during pregnancy in Iran: attitudes and practices

    Institute of Scientific and Technical Information of China (English)

    Mojgan Karbakhsh; Zahra Ershadi; Ali Khaji; Fatemeh Rahimi-Sharbaf

    2010-01-01

    Objective: Seat belt use during pregnancy reduces injury to the mother and her fetus. During recent years, the use of seat belts has been mandated by law in Iran. The purpose of this study was to determine the attitudes and practices of pregnant women regarding seat belt use.Methods: In this cross-sectional study, we asked 335 pregnant women at a hospital-based prenatal care clinic on the use of safety belt before and during pregnancy. SPSS version 13.0 was used for data analysis.Results: The mean age of study subjects was 27.3 years±5.3 years with the median of 27 years. Compared with the seat belt use before pregnancy, no change was detected in 48.7% of the women; seat belt use had increased in 17.5 %of them and decreased in 33.8 %. Eighty-one percent of women knew the correct placing of both lap belt and shoulder belt. Only 4% of women had received education on proper restraint use during pregnancy.Conclusions: The prevalence of seat belt use during pregnancy is lower than reports which are mostly from developed nations. The fact that about one-third of women have decreased their seat belt usage during pregnancy highlights the importance of education of mothers on this topic.

  5. Inclusões fluidas crepitadas, fluidos hipersalinos e aquo-carbônicos em quartzo associado a rochas micáceas no Granito Xinguara - Terreno Granito-Greenstone de Rio Maria, PA Decrepitated fluid inclusions, aqueous-carbonic and hypersaline fluids in quartz associated to micaceous rocks in the Xinguara Granite - Rio Maria Granite - Greenstone terrain, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Leopoldo Weber

    2008-03-01

    Full Text Available As rochas micáceas encontradas no Granito Xinguara, terreno Granito-Greenstone de Rio Maria, Pará, são compostas por muscovita e clorita com níveis de quartzo intercalados, que formam uma xistosidade bem desenvolvida. Essa xistosidade é cortada por veios de quartzo. Ambas as gerações de quartzo apresentam os mesmos tipos de inclusões fluidas em halos ou trilhas secundárias de composições variadas entre aquosas, aquo-carbônicas e saturadas em torno de grandes inclusões primárias crepitadas ou em trilhas transgranulares secundárias. A grande variação de temperaturas de homogeneização, a alta salinidade, as evidências de estrangulamento e a existência das inclusões crepitadas permitem supor forte influência de alterações pós-formacionais e reequilíbrio relacionados à intrusão do granito. Essas rochas foliadas são, portanto, enclaves metassedimentares afetados por fluidos graníticos hipersalinos aquo-carbônicos.The micaceous rocks occurring in the Xinguara Granite, Rio Maria Granite-Greenstone terrain, Pará State, Brazil, are composed of muscovite and chlorite with quartz levels intercalated forming a well developed schistosity. This schistosity is cut by quartz veins. Both quartz generations show the same aqueous, aqueous-carbonic and halite-bearing fluid inclusions either in secondary inclusions halos and trails surrounding decrepitated primary fluid inclusions or in transgranular secondary trails. A wide variation of homogenization temperatures, high salinity, necking down and the decrepitated inclusions existence indicates strong influence of post-formational alteration and reequilibration linked to the granite intrusion. These foliated rocks are metasedimentary enclaves affected by late hypersaline aqueous-carbonic granitic fluids.

  6. Early Archaean collapse basins, a habitat for early bacterial life.

    Science.gov (United States)

    Nijman, W.

    For a better definition of the sedimentary environment in which early life may have flourished during the early Archaean, understanding of the basin geometry in terms of shape, depth, and fill is a prerequisite. The basin fill is the easiest to approach, namely from the well exposed, low-grade metamorphic 3.4 - 3.5 Ga rock successions in the greenstone belts of the east Pilbara (Coppin Gap Greenstone Belt and North Pole Dome) in West Australia and of the Barberton Greenstone Belt (Buck Ridge volcano-sedimentary complex) in South Africa. They consist of mafic to ultramafic volcanic rocks, largely pillow basalts, with distinct intercalations of intermediate to felsic intrusive and volcanic rocks and of silicious sediments. The, partly volcaniclastic, silicious sediments of the Buck Ridge and North Pole volcano-sedimentary complexes form a regressive-transgressive sequence. They were deposited close to base level, and experienced occasional emersion. Both North Pole Chert and the chert of the Kittys Gap volcano-sedimentary complex in the Coppin Gap Greenstone Belt preserve the flat-and-channel architecture of a shallow tidal environment. Thickness and facies distribution appear to be genetically linked to systems, i.e. arrays, of syn-depositionally active, extensional faults. Structures at the rear, front and bottoms of these fault arrays, and the fault vergence from the basin margin towards the centre characterize the basins as due to surficial crustal collapse. Observations in the Pilbara craton point to a non-linear plan view and persistence for the basin-defining fault patterns over up to 50 Ma, during which several of these fault arrays became superposed. The faults linked high-crustal level felsic intrusions within the overall mafic rock suite via porphyry pipes, black chert veins and inferred hydrothermal circulations with the overlying felsic lavas, and more importantly, with the cherty sediments. Where such veins surfaced, high-energy breccias, and in the

  7. Health Monitoring for Coated Steel Belts in an Elevator System

    OpenAIRE

    Yimei Mao; Zuoying Huang; Guiyun Tian; Hui Zhao; Huaming Lei

    2012-01-01

    This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of ...

  8. Modal analysis of coupled vibration of belt drive systems

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-jun; CHEN Li-qun

    2008-01-01

    The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.

  9. Health Monitoring for Coated Steel Belts in an Elevator System

    Directory of Open Access Journals (Sweden)

    Huaming Lei

    2012-01-01

    Full Text Available This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of the most dangerous section as well as other ones along the whole belts.

  10. CHAOTIC BELT PHENOMENA IN NONLINEAR ELASTIC BEAM

    Institute of Scientific and Technical Information of China (English)

    张年梅; 杨桂通

    2003-01-01

    The chaotic motions of axial compressed nonlinear elastic beam subjected totransverse load were studied. The damping force in the system is nonlinear. Consideringmaterial and geometric nonlinearity, nonlinear governing equation of the system wasderived. By use of nonlinear Galerkin method, differential dynamic system was set up.Melnikov method was used to analyze the characters of the system. The results showed thatchaos may occur in the system when the load parameters P0 and f satisfy some conditions.The zone of chaotic motion was belted. The route from subharmonic bifurcation to chaoswas analyzed. The critical conditions that chaos occurs were determined.

  11. Dust bands in the asteroid belt

    Science.gov (United States)

    Sykes, Mark V.; Greenberg, Richard; Dermott, Stanley F.; Nicholson, Philip D.; Burns, Joseph A.

    1989-01-01

    This paper describes the original IRAS observations leading to the discovery of the three dust bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the dust band torus and to theories concerning the origin of the dust bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of dust-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS dust-band observations.

  12. Parametric resonances of convection belt system

    Institute of Scientific and Technical Information of China (English)

    Zhi-an YANG; Gao-feng LI

    2009-01-01

    Based on the Coriolis acceleration and the Lagrangian strain formula,a generalized equation for the transverse vibration system of convection belts is derived using Newton's second law.The method of multiple scales is directly applied to the governing equations,and an approximate solution of the primary parameter resonance of the system is obtained.The detuning parameter,cross-section area,elastic and viscoelastic parameters,and axial moving speed have a significant influences on the amplitudes of steady-state response and their existence boundaries.Some new dynamical phenomena are revealed.

  13. Stabilization of electrostatic accelerator charging belt current

    International Nuclear Information System (INIS)

    For the purpose of improving reliability and quality of electrostatic accelerator basic parameters the stabilizer of charging belt current is developed. The stabilizer consists of two units: high-voltage unit and control unit. The charging rectifier assures voltage up to 60 kV at total current load of 750 μA. For the EG- 2.5 and the EGP-10 M accelerators supply circuits of charging device with an earth screen and posAitive voltage supply the needles. t the EGP-10-1 accelerator negative charging voltage is supplied to the screens of the charging device. ''Plus'' of the rectifier is earthed. Charging and recharging are performed by means of brushes slipping over the internal belt side. At all accelerators the stability of charging current mean value is not worse 0.1%. The highest response of the system are obtained at the EG-2.5 accelerator for account of rectifier load by charging current and instrument resistor from 140 to 400 MOhm

  14. Fading of Jupiter's South Equatorial Belt

    Science.gov (United States)

    Sola, Michael A.; Orton, Glenn; Baines, Kevin; Yanamandra-Fisher, Padma

    2011-01-01

    One of Jupiter's most dominant features, the South Equatorial Belt, has historically gone through a "fading" cycle. The usual dark, brownish clouds turn white, and after a period of time, the region returns to its normal color. Understanding this phenomenon, the latest occurring in 2010, will increase our knowledge of planetary atmospheres. Using the near infrared camera, NSFCAM2, at NASA's Infrared Telescope Facility in Hawaii, images were taken of Jupiter accompanied by data describing the circumstances of each observation. These images are then processed and reduced through an IDL program. By scanning the central meridian of the planet, graphs were produced plotting the average values across the central meridian, which are used to find variations in the region of interest. Calculations using Albert4, a FORTRAN program that calculates the upwelling reflected sunlight from a designated cloud model, can be used to determine the effects of a model atmosphere due to various absorption, scattering, and emission processes. Spectra that were produced show ammonia bands in the South Equatorial Belt. So far, we can deduce from this information that an upwelling of ammonia particles caused a cloud layer to cover up the region. Further investigations using Albert4 and other models will help us to constrain better the chemical make up of the cloud and its location in the atmosphere.

  15. Young Stellar Objects in the Gould Belt

    CERN Document Server

    Dunham, Michael M; Evans, Neal J; Broekhoven-Fiene, Hannah; Cieza, Lucas; Di Francesco, James; Gutermuth, Robert A; Harvey, Paul M; Hatchell, Jennifer; Heiderman, Amanda; Huard, Tracy; Johnstone, Doug; Kirk, Jason M; Matthews, Brenda C; Miller, Jennifer F; Peterson, Dawn E; Young, Kaisa E

    2015-01-01

    We present the full catalog of Young Stellar Objects (YSOs) identified in the 18 molecular clouds surveyed by the Spitzer Space Telescope "cores to disks" (c2d) and "Gould Belt" (GB) Legacy surveys. Using standard techniques developed by the c2d project, we identify 3239 candidate YSOs in the 18 clouds, 2966 of which survive visual inspection and form our final catalog of YSOs in the Gould Belt. We compile extinction corrected SEDs for all 2966 YSOs and calculate and tabulate the infrared spectral index, bolometric luminosity, and bolometric temperature for each object. We find that 326 (11%), 210 (7%), 1248 (42%), and 1182 (40%) are classified as Class 0+I, Flat-spectrum, Class II, and Class III, respectively, and show that the Class III sample suffers from an overall contamination rate by background AGB stars between 25% and 90%. Adopting standard assumptions, we derive durations of 0.40-0.78 Myr for Class 0+I YSOs and 0.26-0.50 Myr for Flat-spectrum YSOs, where the ranges encompass uncertainties in the ado...

  16. 30 CFR 57.4263 - Underground belt conveyors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground belt conveyors. 57.4263 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Firefighting Equipment § 57.4263 Underground belt conveyors. Fire protection shall...

  17. Ambient Response Analysis of the Great Belt Bridge

    DEFF Research Database (Denmark)

    Brincker, Rune; Frandsen, J. B.; Andersen, P.

    2000-01-01

    In this paper an ambient response analysis of the Great Belt Bridge is presented. The Great Belt Bridge is one of the largest suspension bridges in the world, and the analysis was carried out in order to investigate the possibilities of estimating reliable damping values from the ambient response...

  18. Teaching Taekwondo in Physical Education: Incorporating the Color Belt System

    Science.gov (United States)

    Oh, Hyun-Ju; Hannon, James C.; Banks, Aaron

    2006-01-01

    Taekwondo is an excellent lifetime physical activity that provides both physical and mental benefits to its participants. The color belt system may be creatively used in physical education to encourage improvement in all learning domains. This article provides information on incorporating the color belt system into physical education, and provides…

  19. Safety belt usage in Finland and in other Nordic countries.

    NARCIS (Netherlands)

    Valtonen, J.

    1992-01-01

    Legislation has played a significant role in increasing safety belt usage in Finland and in the other Nordic countries. Publicity and enforcement have, however, been required to support the legislation. The development of safety belt regulations has been nearly similar in all these countries, both i

  20. Canadian seat belt wearing rates, promotion programs, and future directions.

    NARCIS (Netherlands)

    Grant, B.A.

    1992-01-01

    On the basis of a national driver seat belt survey conducted in Canada each year, the most important results are presented. A number of programmes for increasing seat belt use has been evaluated in Canada. Finally, a description is given of some of the current and planned activities within Canada wh

  1. Landscape distribution characteristics of northern foothill belts of Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The foothill belts of Tianshan Mountains are about 280 km long and 60 km wide, and the study area extends from Kuitun city to Fukang city. They are transitional belts between mountains and plains, appearing in three rows of folds with different morphologies and their age becoming younger from south to north. Based on GIS and RS methods, and materials of the previous researchers, this paper deals with the genetics of the foothill belts and their landscape features resulting from folding by neotectonic movements, and also describes their length, width and slope by remote sensing image interpretation. The characteristics of the foothill belts are found to be very important for the surrounding environment by preventing groundwater from flowing into plains, changing groundwater, increasing flow of surface runoff, in addition to their roles in protecting the surrounding environment. The purpose of this paper is to provide an in-depth understanding of the foothill belts and influence on its surrounding environment.

  2. a Wave Model for a Pneumatic Tyre Belt

    Science.gov (United States)

    PINNINGTON, R. J.; BRISCOE, A. R.

    2002-06-01

    A one-dimensional wave equation of an infinite flattened tyre belt is generated. The belt vibration is controlled by bending, tension, shear and the sidewall stiffness. The dispersion relations for two waves in the belt are calculated and used to find both the input impedance and attenuation on a tyre belt of infinite extent. Tension and the sidewall controls the deformation and stiffness below 100Hz. Waves propagate around the belt above this frequency. The wave speeds due to bending and shear were predicted and measured. The model presented here should be valid for the prediction of tyre response above about 400 Hz when for a car tyre the modal behaviour is observed to cease. In this high-frequency region, the tyre at the input appears to be of infinite extent.

  3. Radiation-belt dynamics during solar minimum. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Gussenhoven, M.S.; Mullen, E.G.; Holeman, E.

    1989-12-01

    Two types of temporal variation in the radiation belts are studied using low altitude data taken onboard the DMSP F7 satellite: those associated with the solar cycle and those associated with large magnetic storm effects. Over a three-year period from 1984 to 1987 and encompassing solar minimum, the protons in the heart of the inner belt increased at a rate of approximately 6% per year. Over the same period, outer zone electron enhancements declined both in number and peak intensity. During the large magnetic storm of February 1986, following the period of peak ring current intensity, a second proton belt with energies up to 50 MeV was found at magnetic latitudes between 45 deg. and 55 deg. The belt lasted for more than 100 days. The slot region between the inner and outer electron belts collapsed by the merging of the two populations and did not reform for 40 days.

  4. Experimental Measurements of Belt Gears in Newly Developed Device

    Directory of Open Access Journals (Sweden)

    Jozef Mascenik

    2016-05-01

    Full Text Available The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric motor and the tensioning forces are constant and the torque changes.

  5. A Study on the Vibration of the Charging Belt in an Electrostatic Accelerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The vibration of the charging belt in an electrostatic accelerator has intense influences on the accelerator operation. A calculating model was set up in this paper to study the belt vibration. The results show that the belt tension, belt velocity and belt current all contribute to the belt vibration. There is an optimal relationship among the three factors by which the belt would run most smoothly. There exists a minimum value of optimal tension for various belt velocities. The vibrating frequency of the is generally around several Hz.

  6. Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

    Directory of Open Access Journals (Sweden)

    Jieyu Ding

    2014-01-01

    Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

  7. East Central Uplift Belt of Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    @@ Mosuowandong ( Z3 ) and Dongdaohaizi (Z4) are two bidding blocks located in the east part of central uplift Belt, the hinterland of Junggar Basin. Xinjiang Uygur Autonomous Region. It totally covers an area of 8 100km2. Topographically, the two blocks are quite gentle with elevation of 380-400 m on average. The north part is desert and the south area is good for farming. There are three ephemeral streams flowing across the desert from south to north. The ground water is buried at the depth ranging from 6 to 8 m. It belongs to continental climate with the annually averaged precipitation of 80 mm. The traffic is rather convenient in the south part of both blocks. There are several sand-paved roads and two asphalt roads connected with the highway from Karamay to Urumqi City.

  8. The Foundations of Radiation Belt Research

    Science.gov (United States)

    Ludwig, G. H.

    2008-12-01

    phenomenon. It also provided the first hint that there were two distinct radiation belts, although that conclusion was not reached until later. Although that new information was quickly announced, the results of the high altitude nuclear detonations were kept secret until well into 1959. They clearly revealed the charged particle shells created by the Argos nuclear detonations. The next major step in mapping and understanding the high-intensity radiation involved the launch of deep space probes Pioneers III and IV in December 1958 and March 1959. Although both launches fell short in their primary objective, to reach the moon, they traveled far enough from the Earth to fully meet the needs of the scientific experiment. They very clearly showed the two-radiation belt structure, and mapped its extent. They also showed the probable effect of a magnetic storm on 25 February, thus indicating the direct influence of solar activity on the outer belt. By the end of 1959, the existence of the Van Allen Radiation Belts and their general structure were solidly established, early information about the composition of the radiation was appearing in print, and energetic work was under way to understand the physics of the processes involved.

  9. Geometry, kinematics and evolution of the Tongbai orogenic belt

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoying; XU Bei; WANG Changqiu; ZHAN Sheng; DENG Rongjing

    2006-01-01

    The Tongbai orogenic belt (TOB) is composed of six tectonic units. From south to north these units are: Tongbai gneiss rise (TGR); Hongyihe-Luozhuang eclogite belt (HLE); Maopo-Hujiazhai igneous rock belt (MHI); Zhoujiawan flysch belt (ZFB); Yangzhuang greenschist belt (YGB); and Dongjiazhuang marble belt (DMB).The geometry and kinematic images of the TOB include: the antiformal structures caused by a later uplift process, the top-to-north ductile shear structure that related to a process that the ultrahigh pressure rocks are brought to surface, the top-to-south ductile shear thrust and the sinistrial shear structures related to a south-north direction compression, and the east-west direction fold structures in the upper crust. In the view of the multistage subduction-collision orogenic belt, according to the characters of petrology and its distribution, geometry, kinematics and structural chronology in these tectonic units, tectonic evolution of the TOB can be divided into four stages: oceanic crust subduction during 400-300 Ma, continental collision during 270-250 Ma, continental deep subduction and uplift during 250-205 Ma and doming deformation during 200-185 Ma.

  10. The Stratigraphy and Lithofacies of the Paleoproterozoic Volcaniclastic Sequences in the Cape Three Points Area- Akodda section of the Southern in Ashanti Belt in the Birimian of southwest Ghana

    Science.gov (United States)

    Yoshimaru, S.; Kiyokawa, S.; Ito, T.; Ikehara, M.; Nyame, F. K.; Tetteh, G. M.

    2015-12-01

    The Paleoproterozoic Era is thought to have experienced one of the most significant changes in earth's environment during earth history. Early continents started to diverge and collide accompanied by first major oxidation of the atmosphere-oceanic system known as the Great Oxidation Environment (GOE). Due to their well-preserved oceanic sedimentary sequences, Paleoproterozoic belts are usually good targets for studies on the history of earth's past environment. In addition, these belts provide great help to understand the nature of the Paleoproterozoic deeper oceanic environments. Birimian greenstone belt in southwestern Ghana is likely to have made up of subduction of oceanic basin to form a volcanic island arc. Birimian rocks are separated by nonconformity from the Tarkwaian Group which is a younger paleoplacer deposit (Perrouty et al., 2012). The Birimian is made up of island-arc volcanic rocks; foreland basin made up of shale, sandstone, quartzite and turbidities derived from 2.17 Ga granite intrusions during Birimian volcanism. In this study, we focused on the coastal area around Cape Three Points at the southernmost part of the Ashanti (Axim-Konongo) belt in Ghana. In the eastern part of the area, excellently preserved Paleoprotorozoic deeper oceanic sedimentary sequences extensively outcrop for over 4km stretch. This volcano-sedimentary sequence has been affected by greenschist facies metamorphism. Structurally, this region preserves S1 cleavage and asymmetrical synform with west vergence and S0 younging to the east. Provisional stratigraphy is very continuous up to more than 2000m thick and, in addition, suggests at least four different fining upward sequences in the area to the east and west of Atwepo, west of Kwetakora and Akodda. These sub-sequences are mainly composed of volcaniclasitc, sandstone, black shale and rare volcanics such as pillow basalt or massive volcanic lava. In other words, this continuous sequence suggests distal submarine

  11. Power Transmission Through Timing Belt In Two Wheeler Motors

    Directory of Open Access Journals (Sweden)

    Gurumurthy Veerapathiran

    2015-03-01

    Full Text Available This paper studies the effect of noise and friction on performance of the chain drive system for motor bikes. Experiment shows that chain transmission in chain drive system leads to poor overall performance, due to its noise and chain gets loose due to aging and sprockets wear due to chain friction etc., the proposed system consists of drive and driven pulley with timing belt transmission. Compared to conventional method, proposed method give improved tension in pulleys and belt by the additional arrangement called belt tensioner. This gives good overall performance of the system, and reduces noise, vibration and gives high transmission speed.

  12. Detection of Small Kuiper Belt Objects by Stellar Occultations

    OpenAIRE

    Stevenson, R

    2007-01-01

    Knowledge of the Kuiper Belt is currently limited to those objects that can be detected directly. Objects with diameters less than $\\sim$10km reflect too little light to be detected. These smaller bodies could contain most of the mass in the Kuiper Belt while the abundance of these bodies may constrain the distribution of mass. The overall size distribution of bodies within the Kuiper Belt can also be inferred from the relative abundances of sub-km and larger bodies. Stellar occultations are ...

  13. MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS

    Directory of Open Access Journals (Sweden)

    Kazimierz JAMROZ

    2013-12-01

    Full Text Available The article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.

  14. 4 National Standards for Rubber Belt Products Issued

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    On May 20, National General Administration of Quality Supervision, Inspection and Quarantine and National Standardization Administration approved to issue 4 national standards for rubber belt products, which come into effect from October 1.

  15. Face-Saving Devices: Seat Belts and Air Bags

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160032.html Face-Saving Devices: Seat Belts and Air Bags Using ... 11 percent) suffered facial fractures -- nasal and mid-face fractures most often. Those most likely to suffer ...

  16. Periumbilical allergic contact dermatitis: blue jeans or belt buckles?

    Science.gov (United States)

    Byer, Tara T; Morrell, Dean S

    2004-01-01

    Nickel is the most ubiquitous contact allergen among children and adolescents. Metal blue jeans buttons and belts have been noted to cause nickel dermatitis around the umbilicus. For these children, traditional teaching is strict avoidance of all pants with metal snaps/buttons, particularly blue jeans. In this study we tested 90 pairs of blue jeans and 47 belts for nickel using the dimethylglyoxime spot test. Only 10% of blue jeans tested positive, while 53% of belts tested positive. Furthermore, 10 pairs of nickel-negative blue jeans remained negative after 10 washings. Overall we found no resistance to testing in clothing stores. From these results, we recommend that patients with allergic contact dermatitis secondary to nickel need not strictly avoid blue jeans and metal belt buckles. Rather, families should be encouraged to use the dimethylglyoxime spot test to test these items for nickel prior to purchase.

  17. "Abomination"--life as a Bible belt gay.

    Science.gov (United States)

    Barton, Bernadette

    2010-01-01

    Drawing on observation, autoethnography, and audio-taped interviews, this article explores the religious backgrounds and experiences of Bible Belt gays. In the Bible Belt, Christianity is not confined to Sunday worship. Christian crosses, messages, paraphernalia, music, news, and attitudes permeate everyday settings. Consequently, Christian fundamentalist dogma about homosexuality-that homosexuals are bad, diseased, perverse, sinful, other, and inferior-is cumulatively bolstered within a variety of other social institutions and environments in the Bible Belt. Of the 46 lesbians and gay men interviewed for this study (age 18-74 years), most describe living through spirit-crushing experiences of isolation, abuse, and self-loathing. This article argues that the geographic region of the Bible Belt intersects with religious-based homophobia. Informants explained that negative social attitudes about homosexuality caused a range of harmful consequences in their lives including the fear of going to hell, depression, low self-esteem, and feelings of worthlessness.

  18. "Abomination"--life as a Bible belt gay.

    Science.gov (United States)

    Barton, Bernadette

    2010-01-01

    Drawing on observation, autoethnography, and audio-taped interviews, this article explores the religious backgrounds and experiences of Bible Belt gays. In the Bible Belt, Christianity is not confined to Sunday worship. Christian crosses, messages, paraphernalia, music, news, and attitudes permeate everyday settings. Consequently, Christian fundamentalist dogma about homosexuality-that homosexuals are bad, diseased, perverse, sinful, other, and inferior-is cumulatively bolstered within a variety of other social institutions and environments in the Bible Belt. Of the 46 lesbians and gay men interviewed for this study (age 18-74 years), most describe living through spirit-crushing experiences of isolation, abuse, and self-loathing. This article argues that the geographic region of the Bible Belt intersects with religious-based homophobia. Informants explained that negative social attitudes about homosexuality caused a range of harmful consequences in their lives including the fear of going to hell, depression, low self-esteem, and feelings of worthlessness. PMID:20391006

  19. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  20. FORMATION AND EVOLUTION OF THE CENOZOIC THRUST FOLD BELT IN JINPING, SICHUAN

    Institute of Scientific and Technical Information of China (English)

    LIAO Zhongli; DENG Yongfu; LIAO Guangyu

    2003-01-01

    The Jinping orogenic belt in Sichuan, China consists mainly of the Jinpingshan intracontinental thrust-nappe belt, foreland thrust-nappe belt and foreland uplift belt. Based on analyses about the characteristics of the structural units in this area, the authors propose in this paper that Chapuzi-Bazhe revival fault belt is the regional boundary fault, and points out that after the formation of the Pre-Sinian basement, the western edge of the Yangtze paraplatform was turned into the passive continental margin in Sinian to Triassic, then into the Mesozoic collision orogenic belt, and finally into the Cenozoic orogenic belt through intracontinental orogeny.

  1. Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran

    Science.gov (United States)

    Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza

    2016-04-01

    Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or

  2. SPECIFIC RESISTANCE AND SPECIFIC INTENSITY OF BELT SANDING OF WOOD

    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz

    2010-06-01

    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  3. Tribological Properties of Metal V-Belt Type CVT Lubricant

    OpenAIRE

    Keiichi Narita

    2012-01-01

    The priority for lubricant performance for metal V-belt-type CVT (B-CVTFs) should be the improvement of transmittable torque capacity between the belt and pulley plus excellent antishudder properties for lockup clutch used in B-CVTs. This study intends to investigate the effect of lubricant additives for improving these performances of B-CVTs. In addition, surface analysis techniques were utilized to gain a novel insight into the chemical composites and morphology of the tribofilms. As a resu...

  4. Promoting automobile safety belt use by young children.

    OpenAIRE

    Sowers-Hoag, K M; Thyer, B A; Bailey, J S

    1987-01-01

    A program using behavioral practice, assertiveness training, and social and contrived reinforcers was developed to establish and maintain automobile safety belt use by young children. Sixteen children (ages 4.8 to 7 years) who never used their safety belts during a 5-day preexperimental observation period were randomly assigned to two groups of eight each. A multiple baseline design across groups was used to evaluate the effectiveness of the training program. During the 8-day baseline period ...

  5. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  6. Occultation Searches for Kuiper Belt Objects

    CERN Document Server

    Cooray, A R; Cooray, Asantha; Farmer, Alison J.

    2003-01-01

    The occultation of background stellar sources by foreground Kuiper Belt Objects (KBOs) can be used to survey physical properties of the KBO population. We discuss statistics related to a KBO occultation survey, such as the event duration distribution, and suggest that occultation searches can be effectively used to probe the KBO size distribution below 10 km. In particular, we suggest that occultation surveys may be best suited to search for a turnover radius in the KBO size distribution due to collisions between small-size objects. For occultation surveys that monitor stellar sources near the ecliptic over a few square degrees, with time sampling intervals of order 0.1 sec and sensitivity to flux variations of a few percent or more, a turnover radius between 0.1 and 1.0 km can be probed. While occultation surveys will probe the low-radius limit and imaging surveys will detect KBOs of size 100 km or more, statistics of objects with sizes in the intermediate range of around 1 km to 100 km will likely remain un...

  7. Orion revisited III. The Orion Belt population

    CERN Document Server

    Kubiak, K; Bouy, H; Sarro, L M; Ascenso, J; Burkert, A; Forbrich, J; Großschedl, J; Hacar, A; Hasenberger, B; Lombardi, M; Meingast, S; Köhler, R; Teixeira, P S

    2016-01-01

    This paper continues our study of the foreground population to the Orion molecular clouds. The goal is to characterize the foreground population north of NGC 1981 and to investigate the star formation history in the large Orion star-forming region. We focus on a region covering about 25 square degrees, centered on the $\\epsilon$ Orionis supergiant (HD 37128, B0\\,Ia) and covering the Orion Belt asterism. We used a combination of optical (SDSS) and near-infrared (2MASS) data, informed by X-ray (\\textit{XMM-Newton}) and mid-infrared (WISE) data, to construct a suite of color-color and color-magnitude diagrams for all available sources. We then applied a new statistical multiband technique to isolate a previously unknown stellar population in this region. We identify a rich and well-defined stellar population in the surveyed region that has about 2\\,000 objects that are mostly M stars. We infer the age for this new population to be at least 5\\, Myr and likely $\\sim10$\\,Myr and estimate a total of about 2\\,500 mem...

  8. Detecting Mass Loss in Main Belt Asteroids

    Science.gov (United States)

    Sandberg, Erik; Rajagopal, Jayadev; Ridgway, Susan E.; Kotulla, Ralf C.; Valdes, Francisco; Allen, Lori

    2016-01-01

    Sandberg, E., Rajagopal, J., Ridgway, S.E, Kotulla, R., Valdes, F., Allen, L.The Dark Energy Camera (DECam) on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) is being used for a survey of Near Earth Objects (NEOs). Here we attempt to identify mass loss in main belt asteroids (MBAs) from these data. A primary motivation is to understand the role that asteroids may play in supplying dust and gas for debris disks. This work focuses on finding methods to automatically pick out asteroids that have qualities indicating possible mass loss. Two methods were chosen: looking for flux above a certain threshold in the asteroid's radial profile, and comparing its PSF to that of a point source. After sifting through 490 asteroids, several have passed these tests and should be followed up with a more rigorous analysis.Sandberg was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829)

  9. Dark nebulae, dark lanes, and dust belts

    CERN Document Server

    Cooke, Antony

    2012-01-01

    As probably the only book of its type, this work is aimed at the observer who wants to spend time with something less conventional than the usual fare. Because we usually see objects in space by means of illumination of one kind or another, it has become routine to see them only in these terms. However, part of almost everything that we see is the defining dimension of dark shading, or even the complete obscuration of entire regions in space. Thus this book is focused on everything dark in space: those dark voids in the stellar fabric that mystified astronomers of old; the dark lanes reported in many star clusters; the magical dust belts or dusty regions that have given so many galaxies their identities; the great swirling 'folds' that we associate with bright nebulae; the small dark feature detectable even in some planetary nebulae; and more. Many observers pay scant attention to dark objects and details. Perhaps they are insufficiently aware of them or of the viewing potential they hold, but also it may be...

  10. Forming the Cold Classical Kuiper Belt in a light Disk

    CERN Document Server

    Shannon, Andrew; Lithwick, Yoram

    2015-01-01

    Large Kuiper Belt Objects are conventionally thought to have formed out of a massive planetesimal belt that is a few thousand times its current mass. Such a picture, however, is incompatible with multiple lines of evidence. Here, we present a new model for the conglomeration of Cold Classical Kuiper belt objects, out of a solid belt only a few times its current mass, or a few percent of the solid density in a Minimum Mass Solar Nebula. This is made possible by depositing most of the primordial mass in grains of size centimetre or smaller. These grains collide frequently and maintain a dynamically cold belt out of which large bodies grow efficiently: an order-unity fraction of the solid mass can be converted into large bodies, in contrast to the ~0.1% efficiency in conventional models. Such a light belt may represent the true outer edge of the Solar system, and it may have effectively halted the outward migration of Neptune. In addition to the high efficiency, our model can also produce a mass spectrum that pe...

  11. Delivery of meteorites from the asteroid belt

    Science.gov (United States)

    Nolan, Michael Craig

    The process of the delivery of meteorites to the surface of the Earth from plausible source regions such as the asteroid belt is currently understood in general terms, but important uncertainties and conflicts remain to be resolved. Stochastic effects of the rare disruptions of large asteroids on the population of meteorite-sized Earth-crossing asteroids can change the flux and the proportions of compositional types in the infalling meteorite population. These changes can be significant in magnitude over timescales of 108 years. Changes of the order of 1 percent can be expected on timescales of 105-106 y, consistent with small differences between the Antarctic meteorites and modern falls. The magnitude of changes depends strongly on poorly-understood details of collisions. Asteroids 961 Gaspra and 243 Ida were recently imaged by the Galileo spacecraft. I use a numerical hydrocode model to examine the outcomes of various sire impacts into targets the sizes of these asteroids. A shock wave fractures the asteroid in advance of crater excavation flow; thus, for impactors larger than 100 m, impacting at 5.3 km s-1, tensile strength is unimportant in these bodies, whether they are initially intact or are 'rubble piles'. Because of the shock-induced fracture, impact results are controlled by gravity. Therefore these asteroids are much more resistant to catastrophic disruption than predicted by previous estimates, which had assumed that strength was controlling these processes for rock targets. Fracture of km-size asteroids is different from fracture in terrestrial experiments using few-cm targets. The composition distribution of delivered meteorites depends on the outcomes of such asteroid impacts.

  12. Activating main belt comets by collisions

    Science.gov (United States)

    Maindl, T. I.; Haghighipour, N.; Schäfer, C.; Speith, R.

    2016-02-01

    Since their identification as a new class of bodies by Hsieh and Jewitt in 2006 active asteroids (or Main Belt Comets, MBCs) have attracted a great deal of interest. Given that sublimation of volatile material (presumably water-ice) drives MBC activity, these bodies are probable candidates for delivering a significant amount of Earth's water. Dynamical studies suggest in-situ formation of MBCs as the remnants of the break-up of large icy asteroids. Also, collisions between MBCs and small objects might have exposed sub-surface water-ice triggering the cometary activity of these bodies. In order to advance the effort of understanding the nature of MBC activation, we have investigated these collision processes by simulating the impacts in detail using a smooth particle hydrodynamics (SPH) approach that includes material strength and fracture models. Our simulations cover a range of impact velocities (between 0.5 km/s and 5.3 km/s) and angles, allowing m-sized impactors to erode enough of an MBC's surface to expose volatiles and trigger its activation. We also varied the material strength of the active asteroid's surface to study its influence on crater depths and shapes. As expected, depending on the impact energy, impact angle, and MBC's material strength we observe different crater depths. Across all scenarios however, our results show that the crater depths do not exceed a few meters. This implies that if the activity of MBCs is due to sublimating water-ice, ice has to exist in no deeper than a few meters from the surface.

  13. Meningococcal carriage in the African meningitis belt

    Science.gov (United States)

    2013-01-01

    A meningococcal serogroup A polysaccharide/tetanus toxoid conjugate vaccine (PsA-TT) (MenAfriVac#x2122;) is being deployed in countries of the African meningitis belt. Experience with other polysaccharide/protein conjugate vaccines has shown that an important part of their success has been their ability to prevent the acquisition of pharyngeal carriage and hence to stop transmission and induce herd immunity. If PsA-TT is to achieve the goal of preventing epidemics, it must be able to prevent the acquisition of pharyngeal carriage as well as invasive meningococcal disease and whether PsA-TT can prevent pharyngeal carriage needs to be determined. To address this issue, a consortium (the African Meningococcal Carriage (MenAfriCar) consortium) was established in 2009 to investigate the pattern of meningococcal carriage in countries of the African meningitis belt prior to and after the introduction of PsA-TT. This article describes how the consortium was established, its objectives and the standardised field and laboratory methods that were used to achieve these objectives. The experience of the MenAfriCar consortium will help in planning future studies on the epidemiology of meningococcal carriage in countries of the African meningitis belt and elsewhere. Un vaccin conjugué contenant un polysaccharide du sérogroupe A méningococcique et une anatoxine du tétanos (PsA-TT) (MenAfriVac™) est en cours de déploiement dans les pays de la ceinture africaine de la méningite. L’ expérience avec d’ autres vaccins conjugués polysaccharide/protéine a montré qu’ une partie importante de leur succès a été leur capacité à empêcher l’ acquisition du portage pharyngé et donc à arrêter la transmission et à induire une immunité de group. Si PsA-TT doit d’ atteindre l’ objectif de prévenir les épidémies, il devrait être en mesure d’ empêcher l’ acquisition du portage pharyngé ainsi que la méningococcie invasive et le fait que PsA-TT puisse emp

  14. Meningococcal carriage in the African meningitis belt

    Science.gov (United States)

    2013-01-01

    A meningococcal serogroup A polysaccharide/tetanus toxoid conjugate vaccine (PsA-TT) (MenAfriVac#x2122;) is being deployed in countries of the African meningitis belt. Experience with other polysaccharide/protein conjugate vaccines has shown that an important part of their success has been their ability to prevent the acquisition of pharyngeal carriage and hence to stop transmission and induce herd immunity. If PsA-TT is to achieve the goal of preventing epidemics, it must be able to prevent the acquisition of pharyngeal carriage as well as invasive meningococcal disease and whether PsA-TT can prevent pharyngeal carriage needs to be determined. To address this issue, a consortium (the African Meningococcal Carriage (MenAfriCar) consortium) was established in 2009 to investigate the pattern of meningococcal carriage in countries of the African meningitis belt prior to and after the introduction of PsA-TT. This article describes how the consortium was established, its objectives and the standardised field and laboratory methods that were used to achieve these objectives. The experience of the MenAfriCar consortium will help in planning future studies on the epidemiology of meningococcal carriage in countries of the African meningitis belt and elsewhere. Un vaccin conjugué contenant un polysaccharide du sérogroupe A méningococcique et une anatoxine du tétanos (PsA-TT) (MenAfriVac™) est en cours de déploiement dans les pays de la ceinture africaine de la méningite. L’ expérience avec d’ autres vaccins conjugués polysaccharide/protéine a montré qu’ une partie importante de leur succès a été leur capacité à empêcher l’ acquisition du portage pharyngé et donc à arrêter la transmission et à induire une immunité de group. Si PsA-TT doit d’ atteindre l’ objectif de prévenir les épidémies, il devrait être en mesure d’ empêcher l’ acquisition du portage pharyngé ainsi que la méningococcie invasive et le fait que PsA-TT puisse emp

  15. Digital Spectra and Analysis of Altitudinal Belts in Tianshan Mountains,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Baiping; MO Shenguo; WU Hongzhi; XIAO Fei

    2004-01-01

    Based on the framework of the geo-info spectra of montane altitudinal belts, this paper firstly reviews six classification systems for the spectra of mountain altitudinal belts in China and considers that detailed regional study of altitudinal belts is the key for reaching standardization and systemization of mountain altitudinal belts. Only can this furtheridentify and resolve problems with the study of altitudinal belts. The factors forming the spectra of altitudinal belts are analyzed in the Tianshan Mountains of China, and a digital altitudinal belt system is constructed for the northern flank, Southern flank, the heartland, and Ilivalley in the west. The characteristics of each belt are revealed with a summarization of the pattern of areal differentiation of altitudinal belts.

  16. A Physical Model of Electron Radiation Belts of Saturn

    Science.gov (United States)

    Lorenzato, L.; Sicard-Piet, A.; Bourdarie, S.

    2012-04-01

    Radiation belts causes irreversible damages on on-board instruments materials. That's why for two decades, ONERA proposes studies about radiation belts of magnetized planets. First, in the 90's, the development of a physical model, named Salammbô, carried out a model of the radiation belts of the Earth. Then, for few years, analysis of the magnetosphere of Jupiter and in-situ data (Pioneer, Voyager, Galileo) allow to build a physical model of the radiation belts of Jupiter. Enrolling on the Cassini age and thanks to all information collected, this study permits to adapt Salammbô jovian radiation belts model to the case of Saturn environment. Indeed, some physical processes present in the kronian magnetosphere are similar to those present in the magnetosphere of Jupiter (radial diffusion; interaction of energetic electrons with rings, moons, atmosphere; synchrotron emission). However, some physical processes have to be added to the kronian model (compared to the jovian model) because of the particularity of the magnetosphere of Saturn: interaction of energetic electrons with neutral particles from Enceladus, and wave-particle interaction. This last physical process has been studied in details with the analysis of CASSINI/RPWS (Radio and Plasma Waves Science) data. The major importance of the wave particles interaction is now well known in the case of the radiation belts of the Earth but it is important to investigate on its role in the case of Saturn. So, importance of each physical process has been studied and analysis of Cassini MIMI-LEMMS and CAPS data allows to build a model boundary condition (at L = 6). Finally, results of this study lead to a kronian electrons radiation belts model including radial diffusion, interactions of energetic electrons with rings, moons and neutrals particles and wave-particle interaction (interactions of electrons with atmosphere particles and synchrotron emission are too weak to be taken into account in this model). Then, to

  17. Evolution of the Bhandara-Balaghat granulite belt along the southern margin of the Sausar Mobile Belt of central India

    Indian Academy of Sciences (India)

    H M Ramachandra; Abhinaba Roy

    2001-12-01

    The Bhandara-Balaghat granulite (BBG) belt occurs as a 190 km long, detached narrow, linear, NE-SW to ENE-WSW trending belt that is in tectonic contact on its northern margin with the Sausar Group of rocks and is bordered by the Sakoli fold belt in the south. The Bhandara part of the BBG belt is quite restricted, comprising a medium to coarse grained two-pyroxene granulite body that is of gabbroic composition and preserves relic igneous fabric. The main part of the belt in Arjuni-Balaghat section includes metasedimentary (quartzite, BIF, Al- and Mg-Al metapelites) and metaigneous (metaultramafic, amphibolite and two-pyroxene granulite) protoliths interbanded with charnockite and charnockitic gneiss. These rocks, occurring as small bands and enclaves within migmatitic and granitic gneisses, show polyphase deformation and metamorphism. Geochemically, basic compositions show tholeiitic trend without Fe-enrichment, non-komatitic nature, continental affinity and show evolved nature. Mineral parageneses and reaction textures in different rock compositions indicate early prograde, dehydration melt forming reactions followed by orthopyroxene stability with or without melt. Coronitic and symplectitic garnets have formed over earlier minerals indicating onset of retrograde IBC path. Evidences for high temperature ductile shearing are preserved at places. Retrogressive hydration events clearly post-date the above paths. The present study has shown that the BBG belt may form a part of the Bastar Craton and does not represent exhumed oceanic crust of the Bundelkhand Craton. It is further shown that rocks of the BBG belt have undergone an earlier high-grade granulite metamorphism at 2672 ± 54 Ma (Sm-Nd age) and a post-peak granulite metamorphism at 1416 ± 59 Ma (Sm-Nd age, 1380 ± 28 Ma Rb-Sr age). These events were followed by deposition of the Sausar supracrustals and Neoproterozoic Sausar orogeny between 973 ± 63 Ma and 800 ± 16 Ma (Rb-Sr ages).

  18. Rotationally driven 'zebra stripes' in Earth's inner radiation belt.

    Science.gov (United States)

    Ukhorskiy, A Y; Sitnov, M I; Mitchell, D G; Takahashi, K; Lanzerotti, L J; Mauk, B H

    2014-03-20

    Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn, the electric field produced in the inner magnetosphere by Earth's rotation can change the velocity of trapped particles by only about 1-2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth's inner radiation belt are organized in regular, highly structured and unexpected 'zebra stripes', even when the solar-wind activity is low. Modelling reveals that the patterns are produced by Earth's rotation. Radiation-belt electrons are trapped in Earth's dipole-like magnetic field, where they undergo slow longitudinal drift motion around the planet because of the gradient and curvature of the magnetic field. Earth's rotation induces global diurnal variations of magnetic and electric fields that resonantly interact with electrons whose drift period is close to 24 hours, modifying electron fluxes over a broad energy range into regular patterns composed of multiple stripes extending over the entire span of the inner radiation belt. PMID:24646996

  19. JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

    Energy Technology Data Exchange (ETDEWEB)

    Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, 00133, Rome (Italy)

    2012-05-01

    The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.

  20. Flat belt continuously variable high speed drive. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kumm, E.L.

    1992-02-01

    A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley ``turbine`` (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the ``turbine`` corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the ``turbine`` belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.

  1. Research on Dynamic Tension for Belt Conveyor with Constant Force Automatic Take-Up Assembly

    Institute of Scientific and Technical Information of China (English)

    MENG Guo-ying; CHEN Jing-li; LI Yu-jin

    2003-01-01

    The article Provides a dynamic model for belt conveyor. Based on the drive-force of conveyor, take-up tension of take-up assembly, gravity of conveyor belt and material, and friction between belt and idlers, it gives a viscoelastic dynamic equation for conveyor belt. It presents a calculation method of analytic solution to both viscoelastic dynamic equation and geometric dynamic equation when automatic take-up assembly is applied to belt conveyor. The article also makes a study of design method of limiting and eliminating the conveyor belt's elastic vibration.

  2. Aqueous alteration on main-belt asteroids

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  3. Two new basaltic asteroids in the Outer Main Belt

    CERN Document Server

    Duffard, R

    2007-01-01

    The identification of other basaltic objects in the asteroid belt is mandatory to explain the diversity in the collection of basaltic meteorites. This diversity requires more than one differentiated parent body, a fact that is consistent with the diversity of differentiated parent bodies implied by the iron meteorites. Based on a list of previously identified candidate basaltic (V-type) asteroids, two asteroids in the outer main belt, (7472) Kumakiri and (10537) 1991 RY16, were spectroscopically observed during an observational run in Calar Alto Observatory, Spain. We confirm the V-type character of these two asteroids that, together with (1459) Magnya, become the only known traces of basaltic found in the outer main belt up to now. We also demonstrate that the searching for candidate V-type asteroids using a photometric survey, like the Sloan Digital Sky Survey, produces reliable results.

  4. Gravity inferred subsurface structure of Gadwal Schist belt, Andhra Pradesh

    Indian Academy of Sciences (India)

    G Ramadass; I B Ramaprasada Rao; N Srinivasulu

    2001-03-01

    Detailed gravity data collected across the Gadwal schist belt in the state of Andhra Pradesh show an 8.4 mgal residual gravity anomaly associated with meta-sediments/volcanics of the linear NNW-SSE trending schist belt that shows metamorphism from green schist to amphibolite facies. This schist belt is flanked on either side by the peninsular gneissic complex. The elevation and slab Bouguer corrected residual gravity profile data were interpreted using 2-D prism models. The results indicate a synformal structure having a width of 1.8 km at the surface, tapering at a depth of about 2.6 km with a positive density contrast of 0.15 gm/cc with respect to the surrounding peninsular gneissic complex.

  5. Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The purpose of this paper is to analyze the regional fault systems of Qaidam basin and adjacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault systems occurred in the Qaidam and adjacent mountain belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunlun Mountain fault system; (3)Altun strike-slip fault system; (4)Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accumulation belt.

  6. Relativistic surfatron process for Landau resonant electrons in radiation belts

    CERN Document Server

    Osmane, A

    2014-01-01

    Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\\theta$ in close proximity to a critical propagation $\\theta_\\textrm{c}$ associated with a Hopf--Hopf bifurcation condition. In this report, we extend previous studies to reach greater modeling capacities for the study of electrons in radiation belts by including longitudinal wave effects and inhomogeneous magnetic fields. We find that even though both effects can limit the surfatron acceleration of electrons in radiation belts, gains in energy of the order of 100 keV, taking place on the order of ten milliseconds, are sufficiently strong for the mechanism to be relevant to radiation belt dynamics.

  7. TAKRAF belt conveyors - effective means of transport for bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Peterman, L.

    1988-11-01

    Presents belt conveyor types produced by TAKRAF, especially those intended for use at surface mines. The FAM works (Transport Equipment) produces belt conveyors 800-1,400 mm wide, with 2.09-5.24 m/s belt velocity, 460-3,750 m/sup 3//h capacity, max. feed distance 2,500 m and (1-5)x55 kW drive power. The drive stations are based on pontoons or caterpillar vehicles while the end-stations are based on pontoons. Charging hoppers have autonomic drives and are mobile on rail. The described conveyors can also be used in power plants. The FAM works produces 650-800 mm wide conveyors for thermal electric power stations. The conveyors are equipped with metal detectors and metal separators.

  8. The Belt voice: Acoustical measurements and esthetic correlates

    Science.gov (United States)

    Bounous, Barry Urban

    This dissertation explores the esthetic attributes of the Belt voice through spectral acoustical analysis. The process of understanding the nature and safe practice of Belt is just beginning, whereas the understanding of classical singing is well established. The unique nature of the Belt sound provides difficulties for voice teachers attempting to evaluate the quality and appropriateness of a particular sound or performance. This study attempts to provide answers to the question "does Belt conform to a set of measurable esthetic standards?" In answering this question, this paper expands on a previous study of the esthetic attributes of the classical baritone voice (see "Vocal Beauty", NATS Journal 51,1) which also drew some tentative conclusions about the Belt voice but which had an inadequate sample pool of subjects from which to draw. Further, this study demonstrates that it is possible to scientifically investigate the realm of musical esthetics in the singing voice. It is possible to go beyond the "a trained voice compared to an untrained voice" paradigm when evaluating quantitative vocal parameters and actually investigate what truly beautiful voices do. There are functions of sound energy (measured in dB) transference which may affect the nervous system in predictable ways and which can be measured and associated with esthetics. This study does not show consistency in measurements for absolute beauty (taste) even among belt teachers and researchers but does show some markers with varying degrees of importance which may point to a difference between our cognitive learned response to singing and our emotional, more visceral response to sounds. The markers which are significant in determining vocal beauty are: (1) Vibrancy-Characteristics of vibrato including speed, width, and consistency (low variability). (2) Spectral makeup-Ratio of partial strength above the fundamental to the fundamental. (3) Activity of the voice-The quantity of energy being produced. (4

  9. Traffic restrictions due to wind on the Fehmarn Belt bridge

    DEFF Research Database (Denmark)

    Dellwik, E.; Mann, Jakob; Rosenhagen, G.

    2006-01-01

    This report documents the calculations carried out in order to estimate the wind climate at the site where the Fehmarn Belt bridge is planned. Further, an estimate of how often and for how long traffic restrictions will be enforced according to statedcriteria (sec. 3.2) is given. This estimate...... are the same as used in this report and here the comparison is satisfactory. We estimate that the prospective Fehmarn Belt bridge will be closed roughly 2% of the timefor light roadway vehicles (unloaded trucks and caravans), corresponding to 7 days per year. This is slightly less than for the Fehmarnsund...

  10. Bifurcation for Dynamical Systems of Planet-Belt Interaction

    OpenAIRE

    Jiang, Ing-Guey; Yeh, Li-Chin

    2002-01-01

    The dynamical systems of planet-belt interaction are studied by the fixed-point analysis and the bifurcation of solutions on the parameter space is discussed. For most cases, our analytical and numerical results show that the locations of fixed points are determined by the parameters and these fixed points are either structurally stable or unstable. In addition to that, there are two special fixed points: the one on the inner edge of the belt is asymptotically stable and the one on the outer ...

  11. Design study of flat belt CVT for electric vehicles

    Science.gov (United States)

    Kumm, E. L.

    1980-01-01

    A continuously variable transmission (CVT) was studied, using a novel flat belt pulley arrangement which couples the high speed output shaft of an energy storage flywheel to the drive train of an electric vehicle. A specific CVT arrangement was recommended and its components were selected and sized, based on the design requirements of a 1700 KG vehicle. A design layout was prepared and engineering calculations made of component efficiencies and operating life. The transmission efficiency was calculated to be significantly over 90% with the expected vehicle operation. A design consistent with automotive practice for low future production costs was considered, together with maintainability. The technology advancements required to develop the flat belt CVT were identified and an estimate was made of how the size of the flat belt CVT scales to larger and smaller design output torques. The suitability of the flat belt CVT for alternate application to an electric vehicle powered by an electric motor without flywheel and to a hybrid electric vehicle powered by an electric motor with an internal combustion engine was studied.

  12. Resolving the Planetesimal Belt of HR 8799 with ALMA

    CERN Document Server

    Booth, Mark; Casassus, Simon; Hales, Antonio S; Dent, William R F; Faramaz, Virginie; Matrà, Luca; Barkats, Denis; Brahm, Rafael; Cuadra, Jorge

    2016-01-01

    The star HR 8799 hosts one of the largest known debris discs and at least four giant planets. Previous observations have found evidence for a warm belt within the orbits of the planets, a cold planetesimal belt beyond their orbits and a halo of small grains. With the infrared data, it is hard to distinguish the planetesimal belt emission from that of the grains in the halo. With this in mind, the system has been observed with ALMA in band 6 (1.34 mm) using a compact array format. These observations allow the inner edge of the planetesimal belt to be resolved for the first time. A radial distribution of dust grains is fitted to the data using an MCMC method. The disc is best fit by a broad ring between $145^{+12}_{-12}$ AU and $429^{+37}_{-32}$ AU at an inclination of $40^{+5}_{-6}${\\deg} and a position angle of $51^{+8}_{-8}${\\deg}. A disc edge at ~145 AU is too far out to be explained simply by interactions with planet b, requiring either a more complicated dynamical history or an extra planet beyond the orb...

  13. Nature of the Kirkwood gaps in the asteroid belt

    Energy Technology Data Exchange (ETDEWEB)

    Dermott, S.F.; Murray, C.D. (Cornell Univ., Ithaca, NY (USA). Lab. for Planetary Studies)

    1983-01-20

    The distributions of orbital eccentricities and inclinations near the Jovian resonances in the asteroid belt show that the observed Kirkwood gaps in the distribution of the semimajor axes were formed after the asteroids had dispersed from the near-coplanar disk in which they accreted.

  14. Uranium deposits of the Grants, New Mexico mineral belt (II)

    International Nuclear Information System (INIS)

    This is part of a study of the genesis of the U deposits of the Grants mineral belt. Enrichment of Mg in ore zones is frequently observed, with chlorite being a common product. Clay mineralogic studies argue for chlorite-illite-montmorillonite associations with ores. The methods include scanning electron microscopy, Eh-pH diagrams, activation analysis, and rare earth element studies

  15. Resolving the planetesimal belt of HR 8799 with ALMA

    Science.gov (United States)

    Booth, Mark; Jordán, Andrés; Casassus, Simon; Hales, Antonio S.; Dent, William R. F.; Faramaz, Virginie; Matrà, Luca; Barkats, Denis; Brahm, Rafael; Cuadra, Jorge

    2016-07-01

    The star HR 8799 hosts one of the largest known debris discs and at least four giant planets. Previous observations have found evidence for a warm belt within the orbits of the planets, a cold planetesimal belt beyond their orbits and a halo of small grains. With the infrared data, it is hard to distinguish the planetesimal belt emission from that of the grains in the halo. With this in mind, the system has been observed with ALMA in band 6 (1.34 mm) using a compact array format. These observations allow the inner edge of the planetesimal belt to be resolved for the first time. A radial distribution of dust grains is fitted to the data using an MCMC method. The disc is best fitted by a broad ring between 145^{+12}_{-12} au and 429^{+37}_{-32} au at an inclination of 40^{+5}_{-6}° and a position angle of 51^{+8}_{-8}°. A disc edge at ˜145 au is too far out to be explained simply by interactions with planet b, requiring either a more complicated dynamical history or an extra planet beyond the orbit of planet b.

  16. Collisional and dynamic evolution of dust from the asteroid belt

    Science.gov (United States)

    Gustafson, Bo A. S.; Gruen, Eberhard; Dermott, Stanley F.; Durda, Daniel D.

    1992-01-01

    The size and spatial distribution of collisional debris from main belt asteroids is modeled over a 10 million year period. The model dust and meteoroid particles spiral toward the Sun under the action of Poynting-Robertson drag and grind down as they collide with a static background of field particles.

  17. Influence of the Gould Belt on Interstellar Extinction

    CERN Document Server

    Gontcharov, George

    2016-01-01

    A new analytical 3D model of interstellar extinction within 500 pc of the Sun as a function of the Galactic spherical coordinates is suggested. This model is physically more justified than the widely used Arenou model, since it takes into account the presence of absorbing matter both in the layer along the equatorial Galactic plane and in the Gould Belt. The extinction in the equatorial layer varies as the sine of the Galactic longitude and in the Gould Belt as the sine of twice the longitude in the Belt plane. The extinction across the layers varies according to a barometric law. It has been found that the absorbing layers intersect at an angle of 17 deg and that the Sun is located near the axial plane of the absorbing layer of the Gould Belt and is probably several parsecs below the axial plane of the equatorial absorbing layer but above the Galactic plane. The model has been tested using the extinction of real stars from three catalogs.

  18. Structural appraisal of the Gadag schist belt from gravity investigations

    Indian Academy of Sciences (India)

    G Ramadass; D Himabindu; N Srinivasulu

    2003-12-01

    Semi-detailed gravity investigations were carried out over an area of approximately 2750 sq km with maximum N-S and E-W extents of 55 and 50km respectively in the Gadag region in the Dharwar craton with a view to obtain a clearer perception of the structural configuration of the region. From qualitative analysis of the gravity data, several tectonic features are inferred: the high density Gadag schist belt is characterized by a gravity high and occurs in two discontinuous segments — the main N-S trending segment, and its thinner NW-SE trending extension, the two separated by a NE-SW trending deep seated fault. While the N-S trend of the Gadag schist belt is bounded on its east by the NW-SE trending Chitradurga thrust fault and on its west by another major NNW-SSE trending fault, the NW-SE extension is likewise bounded by two other NW-SE major faults. Quantitative evaluation from forward modeling/inversion of five profiles in the region, assuming a density contrast of 0.29 gm/cc of the anomalous schistose body with the gneissic host rocks indicated a synclinal structure plunging to the southeast along its axis for the Gadag schist belt. The maximum width and depth from surface of the schist belt are 22km and 5.6km respectively.

  19. 1991 National campaign to increase safety belt usage.

    NARCIS (Netherlands)

    National Highway Traffic Safety Administration NHTSA

    1992-01-01

    The central theme of this paper is the national campaign of the USA to be conducted in 1991 and 1992, in order to reach the goal of 70 percent safety belt usage by 1992. Among other things, it is shown that visible enforcement of existing laws offers the greatest potential for achieving this goal. F

  20. WISE Albedos for Tens of Thousands of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, Joseph R.; Mainzer, A. K.; Bauer, J.; Cutri, R.; Dailey, J.; Delbo, M.; Grav, T.; McMillan, R. S.; Mueller, M.; Walker, R.; Wright, E.; WISE Science Team, [No Value

    2010-01-01

    Using thermal IR data from the Wide-field Infrared Survey Explorer (WISE) mission we have calculated diameters for tens of thousands of previously known Main Belt asteroids. Using archival optical observations we have also determined albedos for each object. We present our results from this investig

  1. Shaping mobile belts by small-scale convection.

    Science.gov (United States)

    Faccenna, Claudio; Becker, Thorsten W

    2010-06-01

    Mobile belts are long-lived deformation zones composed of an ensemble of crustal fragments, distributed over hundreds of kilometres inside continental convergent margins. The Mediterranean represents a remarkable example of this tectonic setting: the region hosts a diffuse boundary between the Nubia and Eurasia plates comprised of a mosaic of microplates that move and deform independently from the overall plate convergence. Surface expressions of Mediterranean tectonics include deep, subsiding backarc basins, intraplate plateaux and uplifting orogenic belts. Although the kinematics of the area are now fairly well defined, the dynamical origins of many of these active features are controversial and usually attributed to crustal and lithospheric interactions. However, the effects of mantle convection, well established for continental interiors, should be particularly relevant in a mobile belt, and modelling may constrain important parameters such as slab coherence and lithospheric strength. Here we compute global mantle flow on the basis of recent, high-resolution seismic tomography to investigate the role of buoyancy-driven and plate-motion-induced mantle circulation for the Mediterranean. We show that mantle flow provides an explanation for much of the observed dynamic topography and microplate motion in the region. More generally, vigorous small-scale convection in the uppermost mantle may also underpin other complex mobile belts such as the North American Cordillera or the Himalayan-Tibetan collision zone. PMID:20520711

  2. PROPOSALS ON IMPROVING THE EXCAVATION, TRANSPORT AND COAL DEPOSIT, USING THE RUBBER CONVEYOR BELT

    Directory of Open Access Journals (Sweden)

    Nicoleta-Maria MIHUT

    2016-05-01

    Full Text Available In this work we make a study of the improvement methods of quantity of material transported by conveyor belt. Determination of discharge of solids entail establish of the parameters of the conveyor belt. As a result, we determine the belt speed who provide maximum discharge of solids materials.

  3. Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue?

    Science.gov (United States)

    Gardiner, Nicholas; Robb, Laurence; Searle, Michael; Morley, Christopher

    2015-04-01

    Myanmar (Burma) is richly endowed in precious and base metals, having one of the most diverse collections of natural resources in SE Asia. Its geological history is dominated by the staged closing of Tethys and the suturing of Gondwana-derived continental fragments onto the South China craton during the Mesozoic-Cenozoic. The country is located at a crucial geologic juncture where the main convergent Tethyan collision zone swings south around the Namche Barwa Eastern Himalayan syntaxis. However, despite recent work, the geological and geodynamic history of Myanmar remains enigmatic. Plate margin processes, magmatism, metasomatism and the genesis of mineral deposits are intricately linked, and there has long been recognized a relationship between the distribution of certain mineral deposit types, and the tectonic settings which favour their genesis. A better knowledge of the regional tectonic evolution of a potential exploration jurisdiction is therefore crucial to understanding its minerals prospectivity. This strong association between tectonics and mineralization can equally be applied in reverse. By mapping out the spatial, and temporal, distribution of presumed co-genetic mineral deposits, coupled with an understanding of their collective metallogenetic origin, a better appreciation of the tectonic evolution of a terrane may be elucidated. Identification and categorization of metallotects within a geodynamically-evolving terrane thus provides a complimentary tool to other methodologies (e.g. geochemical, geochronological, structural, geophysical, stratigraphical), for determining the tectonic history and inferred geodynamic setting of that terrane through time. Myanmar is one such study area where this approach can be undertaken. Here are found two near-parallel magmatic belts, which together contain a significant proportion of that country's mineral wealth of tin, tungsten, copper, gold and silver. Although only a few 100 km's apart, these belts exhibit a

  4. Belt(s) of debris resolved around the Sco-Cen star HIP 67497

    CERN Document Server

    Bonnefoy, M; Ménard, F; Vigan, A; Lagrange, A -M; Delorme, P; Boccaletti, A; Lazzoni, C; Galicher, R; Desidera, S; Chauvin, G; Augereau, J C; Mouillet, D; Pinte, C; van der Plas, G; Gratton, R; Beust, H; Beuzit, J L

    2016-01-01

    In 2015, we initiated a survey of Scorpius-Centaurus A-F stars that are predicted to host warm-inner and cold-outer belts of debris similar to the case of the system HR~8799. The survey aims to resolve the disks and detect planets responsible for the disk morphology. In this paper, we study the F-type star HIP~67497 and present a first-order modelisation of the disk in order to derive its main properties. We used the near-infrared integral field spectrograph (IFS) and dual-band imager IRDIS of VLT/SPHERE to obtain angular-differential imaging observations of the circumstellar environnement of HIP~67497. We removed the stellar halo with PCA and TLOCI algorithms. We modeled the disk emission with the GRaTeR code. We resolve a ring-like structure that extends up to $\\sim$450 mas ($\\sim$50 au) from the star in the IRDIS and IFS data. It is best reproduced by models of a non-eccentric ring with an inclination of $80\\pm1^{\\circ}$, a position angle of $-93\\pm1^{\\circ}$, and a semi-major axis of $59\\pm3$ au. We also ...

  5. TECTONICS OF THE DABIE OROGENIC BELT, CENTRAL CHINA

    Institute of Scientific and Technical Information of China (English)

    GUO Fu-sheng; XIA Fei; PENG Hua-ming; DU Yang-song

    2002-01-01

    Tectonically the Dabie orogenic belt consists mainly of the Dabieshan Yanshanian uplifted zone and the Beihuaiyang Variscan-Indosinian folding zone. In the north boundary adjoining the North China Block, there are an Early Palaeozoic ophiolitic mixtite belt and the Hefei Mesozoic-Cenozoic faulted basin which overlaps on the suture belt. In the south of Dabie orogen, there is a secondary tectonic unit called Foreland thrust-faulted structural zone which was mainly formed by the intracontinental subductions during Mesozoic era. The study shows that the Dabie Block is a part of mid-late Proterozoic palaeo-island arc at the north margin of Yangtze Block. During Caledonian period, as a submerged uplift at the northen continental margin of Yangtze Block, the Dabie Block collided with the early Palaeozoic palaeo-island arc at the south margin of North China Block, resulting in the convergence of the North and South China Blocks and the disappearance of oceanic crust. Since then,large-scale intracontinental subductions were followed. Dabie Orogenic Belt is the product of overlapping of Yangtze Block, Dabie Block and North China Block under the mechanism of intracontinental subduction. Indosinian period is the period of chief deformation and high pressure dynamic metamorphism for Dabie Block, and Yanshan period is the main orogenic period in which the remelting of crust caused by basement shearing resulted in large scale thermometamorphism. The present tectonic framework of the orogen was finally formed by the rapid uplifting of the Dabieshan mountains and gliding southwards, which result in the developing of thrust belt on south side and the extensional tectonic movement on north side.

  6. Flexible electrode belt for EIT using nanofiber web dry electrodes

    International Nuclear Information System (INIS)

    Efficient connection of multiple electrodes to the body for impedance measurement and voltage monitoring applications is of critical importance to measurement quality and practicality. Electrical impedance tomography (EIT) experiments have generally required a cumbersome procedure to attach the multiple electrodes needed in EIT. Once placed, these electrodes must then maintain good contact with the skin during measurements that may last several hours. There is usually also the need to manage the wires that run between the electrodes and the EIT system. These problems become more severe as the number of electrodes increases, and may limit the practicality and portability of this imaging method. There have been several trials describing human–electrode interfaces using configurations such as electrode belts, helmets or rings. In this paper, we describe an electrode belt we developed for long-term EIT monitoring of human lung ventilation. The belt included 16 embossed electrodes that were designed to make good contact with the skin. The electrodes were fabricated using an Ag-plated PVDF nanofiber web and metallic threads. A large contact area and padding were used behind each electrode to improve subject comfort and reduce contact impedances. The electrodes were incorporated, equally spaced, into an elasticated fabric belt. We tested the electrode belt in conjunction with the KHU Mark1 multi-frequency EIT system, and demonstrate time-difference images of phantoms and human subjects during normal breathing and running. We found that the Ag-plated PVDF nanofiber web electrodes were suitable for long-term measurement because of their flexibility and durability. Moreover, the contact impedance and stability of the Ag-plated PVDF nanofiber web electrodes were found to be comparable to similarly tested Ag/AgCl electrodes. (paper)

  7. ASSESSMENT OF HOMEOWNERSHIP AND ASSET POVERTY IN THE ALABAMA BLACK BELT AND NON-BLACK BELT COUNTIES

    OpenAIRE

    Kanyi, Peter M.; Baharanyi, Ntam; Ngandu, Mudiayi Sylvain; Zabawa, Robert

    2008-01-01

    This study assessed homeownership and how it is affected by race, residency in or out of Alabama Black Belt, family status, poverty and other variables. All variables showed significant relationship to Alabama homeownership with single-parenthood showing a negative impact on White homeownership but insignificant to Black homeownership in the region.

  8. Break the Green Belt? The differences between green belt and its alternative green wedge : A comparative study of London and Stockholm

    OpenAIRE

    Kong, Luyao

    2012-01-01

    The paper sets out to compare two widely applied planning strategies--- green belt and green wedge--- to understand if as an alternative, the green wedge has more strengths than green belt. Green belt has long been the planning policy with a steady position in UK, and also accepted by other countries, Australia, Japan, Korea for example. But during recent years, this policy has been under accusation for fostering un-sustainability, housing shortage and value degradation of the green space. A ...

  9. Dynamics of the earth's radiation belts and inner magnetosphere (geophysical monograph series)

    CERN Document Server

    2013-01-01

    Dynamics of the Earth's Radiation Belts and Inner Magnetosphere draws together current knowledge of the radiation belts prior to the launch of Radiation Belt Storm Probes (RPSP) and other imminent space missions, making this volume timely and unique. The volume will serve as a useful benchmark at this exciting and pivotal period in radiation belt research in advance of the new discoveries that the RPSP mission will surely bring. Highlights include the following: a review of the current state of the art of radiation belt science; a complete and up-to-date account of the wave-particle interactions that control the dynamical acceleration and loss processes of particles in the Earth's radiation belts and inner magnetosphere; a discussion emphasizing the importance of the cross-energy coupling of the particle populations of the radiation belts, ring current, and plasmasphere in controlling the dynamics of the inner magnetosphe...

  10. DEVELOPMENT OF THE TEST METHODS OF THE CONVEYOR BELTS USED IN ENVIRONMENTS ENDANGERED BY EXPLOSION HAZARDS

    Directory of Open Access Journals (Sweden)

    Florin Adrian PĂUN

    2012-05-01

    Full Text Available Conveyor belts are used for a long period of time in the industry branches where potentially explosive atmospheres could occur. Dangerous phenomena which can be in direct connection with the use of conveyor belts are the ones regarding: - sparks influence over the coating layer and/or resistance internal structure of the stopped conveyor belt; - propagation of a flame along the length of a conveyor belt that was exposed to a energy source relative high like a fire or due to blockage of a conveyor belt as a result of the driving mechanism still operating, that generate a local heating of the conveyor belt in contact with the driving drum, rollers or any other heating source generated by friction. Determining the safety parameters characteristic of the conveyor belts by employing test methods allows assessment of the safety level as well as certification of their explosion protection quality when used in environments with explosion danger.

  11. Tribological Properties of Metal V-Belt Type CVT Lubricant

    Directory of Open Access Journals (Sweden)

    Keiichi Narita

    2012-01-01

    Full Text Available The priority for lubricant performance for metal V-belt-type CVT (B-CVTFs should be the improvement of transmittable torque capacity between the belt and pulley plus excellent antishudder properties for lockup clutch used in B-CVTs. This study intends to investigate the effect of lubricant additives for improving these performances of B-CVTs. In addition, surface analysis techniques were utilized to gain a novel insight into the chemical composites and morphology of the tribofilms. As a result, it is vital for greater torque capacity to give higher boundary friction coefficient between the metal contacting interfaces, and the process of boundary lubricant film formation derived from antiwear additives used in B-CVTFs strongly impacts on the torque capacity. Moreover, it is found that a sort of lubricant formulation gave an excellent antishudder performance for wet clutch with keeping higher friction coefficient between the metals, which would result in improving the performance of B-CVTs.

  12. MINIMIZATION OF CORD WASTAGES IN BELT INDUSTRY USING DMAIC

    Directory of Open Access Journals (Sweden)

    SHAILESH N. KHEKALE,

    2010-08-01

    Full Text Available Manufacturing processes tend to produce operational wastages due to various reasons, which can be reduced by identifying and eliminating those using Six Sigma methodologies. In the presented work, DMAIC (Define, Measure, Analyze, Improve and Control has been used to reduce cord wastages in belt manufacturing. Core issues, pain areas or processes related to cord wastages are identified to formulate the problem. Later the concerned data is collected to examine the current performance and process capability; also the root causes are identified. Solutions are found out from improvement point of view, and various tools are properly implemented for tracking the processes. This study reports reduction in cord wastages in belt manufacturing through reduction in DPMO (Defects per Million Opportunities from 549531 to 17240, also the Sigma Level isimproved from 1.37 to 3.6.

  13. Statistical properties of the radiation belt seed population

    Science.gov (United States)

    Boyd, A. J.; Spence, H. E.; Huang, C.-L.; Reeves, G. D.; Baker, D. N.; Turner, D. L.; Claudepierre, S. G.; Fennell, J. F.; Blake, J. B.; Shprits, Y. Y.

    2016-08-01

    We present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈0.73 with a time lag of 10-15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of the acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.

  14. Operational experiences with belt rollers for bulk conveying

    Energy Technology Data Exchange (ETDEWEB)

    Dietl, W.

    1982-05-01

    Explains the design of belt rollers produced by TAKRAF for conveyor belts 0.3 m to 3.0 m wide. Light, medium and heavy-duty rollers are manufactured according to a common basic design; the roller diameters range from 63 mm to 245 mm. Major parameters of rollers are discussed, the theoretical roller service life is calculated. Operational conditions which must be observed in order to obtain the theoretical service life in operation are listed. The principle design of the roller is demonstrated in a scheme, focusing on the axial labyrinth seal. Impact forces on rollers at conveyor feeding stations are analyzed. Tests have been carried out using rollers provided with shock absorbing rubber elements compensating the impact load of the bulk, which, however, did not prove to be advantageous. Conclusions on the design of heavy duty rollers to be used at feeding stations are further outlined. (3 refs.) (In German)

  15. The Analysis of Insects Population on Fields in Forest Belts

    OpenAIRE

    Gribust Irina Romuvaldovna

    2014-01-01

    The introduction into the agricultural and ecological system of multifunctional forest belts contributes to the formation of a qualitatively new environment, and, as a consequence, to the transformation of insects populations. Change of the faunal diversity in transformed agro-ecosystems and identification of entomofauna characteristics by a number of biotic indices, which undergo cumulative impact of organized farm ecosystem components, have not been sufficiently studied. This question is th...

  16. Discovery of the candidate Kuiper belt object 1992 QB1

    Science.gov (United States)

    Jewitt, David; Luu, Jane

    1993-01-01

    The discovery of a new faint object in the outer solar system, 1992 QB1, moving beyond the orbit of Neptune is reported. It is suggested that the 1992 QB1 may represent the first detection of a member of the Kuiper belt (Edgworth, 1949; Kuiper, 1951), the hypothesized population of objects beyond Neptune and a possible source of the short-period comets, as suggested by Whipple (1964), Fernandez (1980), and Duncan et al. (1988).

  17. Radiation Belt Electron Dynamics Driven by Large-Amplitude Whistlers

    Science.gov (United States)

    Khazanov, G. V.; Tel'nikhin, A. A.; Kronberg, T. K.

    2013-01-01

    Acceleration of radiation belt electrons driven by oblique large-amplitude whistler waves is studied. We show analytically and numerically that this is a stochastic process; the intensity of which depends on the wave power modified by Bessel functions. The type of this dependence is determined by the character of the nonlinear interaction due to coupling between action and phase. The results show that physically significant quantities have a relatively weak dependence on the wave power.

  18. Future aerosol reductions and widening of the northern tropical belt

    Science.gov (United States)

    Allen, Robert J.; Ajoku, Osinachi

    2016-06-01

    Observations show that the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large-scale atmospheric circulation. Although part of this signal is related to natural climate variability, studies have identified an externally forced contribution primarily associated with greenhouse gases (GHGs) and stratospheric ozone loss. Here we show that the increase in aerosols over the twentieth century has led to contraction of the northern tropical belt, thereby offsetting part of the widening associated with the increase in GHGs. Over the 21st century, however, when aerosol emissions are projected to decrease, the effects of aerosols and GHGs reinforce one another, both contributing to widening of the northern tropical belt. Models that have larger aerosol forcing, by including aerosol indirect effects on cloud albedo and lifetime, yield significantly larger Northern Hemisphere (NH) tropical widening than models with direct aerosol effects only. More targeted simulations show that future reductions in aerosols can drive NH tropical widening as large as greenhouse gases, and idealized simulations show the importance of NH midlatitude aerosol forcing. Mechanistically, the 21st century reduction in aerosols peaks near 40°N, which results in a corresponding maximum increase in surface solar radiation, NH midlatitude tropospheric warming amplification, and a poleward shift in the latitude of maximum baroclinicity, implying a corresponding shift in atmospheric circulation. If models with aerosol indirect effects better represent the real world, then future aerosol changes are likely to be an important -- if not dominant -- driver of NH tropical belt widening.

  19. Development of a new Global RAdiation Belt model: GRAB

    Science.gov (United States)

    Sicard-Piet, Angelica; Lazaro, Didier; Maget, Vincent; Rolland, Guy; Ecoffet, Robert; Bourdarie, Sébastien; Boscher, Daniel; Standarovski, Denis

    2016-07-01

    The well known AP8 and AE8 NASA models are commonly used in the industry to specify the radiation belt environment. Unfortunately, there are some limitations in the use of these models, first due to the covered energy range, but also because in some regions of space, there are discrepancies between the predicted average values and the measurements. Therefore, our aim is to develop a radiation belt model, covering a large region of space and energy, from LEO altitudes to GEO and above, and from plasma to relativistic particles. The aim for the first version is to correct the AP8 and AE8 models where they are deficient or not defined. At geostationary, we developed ten years ago for electrons the IGE-2006 model which was proven to be more accurate than AE8, and used commonly in the industry, covering a broad energy range, from 1keV to 5MeV. From then, a proton model for geostationary orbit was also developed for material applications, followed by the OZONE model covering a narrower energy range but the whole outer electron belt, a SLOT model to asses average electron values for 2file system to switch between models, in order to obtain at each location in space and energy point the most reliable value. Of course, the way the model is developed is well suited to add new local developments or to include international partnership. This model will be called the GRAB model, as Global Radiation Belt model. We will present first beta version during this conference.

  20. The benefit of seat belt legislation in the United Kingdom.

    OpenAIRE

    M. McCarthy

    1989-01-01

    Legislation for compulsory wearing of seat belts by car drivers and front seat passengers has been acclaimed as a major public health advance. Reports from other countries, and two recent evaluative studies in the United Kingdom, have suggested that legislation reduces both deaths and injuries. To assess the effect of the UK law 5 years after its implementation, trends in routine data for 1976-1987 have been reviewed. There were two sources of data: mortality statistics, published by the Offi...

  1. Coralling a distant planet with extreme resonant Kuiper belt objects

    CERN Document Server

    Malhotra, Renu; Wang, Xianyu

    2016-01-01

    The four longest period Kuiper belt objects have orbital periods close to small integer ratios with each other. A hypothetical planet with orbital period $\\sim$17,117 years, semimajor axis $\\sim$665 AU, would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity and the mass of such a planet, as well as its current location in its orbital path.

  2. Rotation Period Determination of Four Main-belt Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2016-10-01

    Observations of four main-belt asteroids (MBA) revealed the following rotation periods and lightcurve amplitudes: 3861 Lorenz, P = 11.91 ± 0.01 h, A = 0.28 mag; 6173 Jimwestphal P = 2.908 ± 0.001 h, A = 0.41 mag; 10259 Osipovyurij, P = 6.356 ± 0.001 h, A = 0.30 mag; 29470 Higgs, P = 36.31 ± 0.01 h, A = 0.48 mag.

  3. Calibration of carbonate composition using micro-Raman analysis: application to planetary surface exploration.

    Science.gov (United States)

    Rividi, Nicolas; van Zuilen, Mark; Philippot, Pascal; Ménez, Bénédicte; Godard, Gaston; Poidatz, Emmanuel

    2010-04-01

    Stromatolite structures in Early Archean carbonate deposits form an important clue for the existence of life in the earliest part of Earth's history. Since Mars is thought to have had similar environmental conditions early in its history, the question arises as to whether such stromatolite structures also evolved there. Here, we explore the capability of Raman spectroscopy to make semiquantitative estimates of solid solutions in the Ca-Mg-Fe(+Mn) carbonate system, and we assess its use as a rover-based technique for stromatolite characterization during future Mars missions. Raman microspectroscopy analysis was performed on a set of carbonate standards (calcite, ankerite, dolomite, siderite, and magnesite) of known composition. We show that Raman band shifts of siderite-magnesite and ankerite-dolomite solid solutions display a well-defined positive correlation (r(2) > 0.9) with the Mg# = 100 x Mg/(Mg + Fe + Mn + Ca) of the carbonate analyzed. Raman shifts calibrated as a function of Mg# were used in turn to evaluate the chemical composition of carbonates. Raman analysis of a suite of carbonates (siderite, sidero-magnesite, ankerite, and dolomite) of hydrothermal and sedimentary origin from the ca. 3.2 Ga old Barite Syncline, Barberton greenstone belt, South Africa, and from the ca. 3.5 Ga old Dresser Formation, Pilbara Craton, Western Australia, show good compositional agreement with electron microprobe analyses. These results indicate that Raman spectroscopy can provide direct information on the composition and structure of carbonates on planetary surfaces.

  4. Trace element mapping of pyrite from Archean gold deposits – A comparison between PIXE and EPMA

    Energy Technology Data Exchange (ETDEWEB)

    Agangi, A., E-mail: aagangi@uj.ac.za [University of Johannesburg, Department of Geology, Auckland Park 2006 (South Africa); Przybyłowicz, W., E-mail: przybylowicz@tlabs.ac.za [Materials Research Department, iThemba LABS, National Research Foundation, Somerset West 7129 (South Africa); AGH University of Science and Technology, Faculty of Physics & Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland); Hofmann, A., E-mail: ahofmann@uj.ac.za [University of Johannesburg, Department of Geology, Auckland Park 2006 (South Africa)

    2015-04-01

    Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P–T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits.

  5. Trace element mapping of pyrite from Archean gold deposits – A comparison between PIXE and EPMA

    International Nuclear Information System (INIS)

    Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P–T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits

  6. Sulfate in the Palaeoarchean Ocean: Localized Enrichment or Variable Preservation?

    Science.gov (United States)

    Mason, P. R. D.; Roerdink, D. L.; Galic, A.; Martin, W.

    2015-12-01

    The Archean oceans are thought to have been depleted in sulfate, reflecting widespread anoxic conditions and limited input of oxidized sulfur species from atmospheric photolysis. This is supported by the paucity of sulfate-bearing minerals and the relatively limited mass-dependent sulfur isotope fractionation in the majority of the Archean geological record. An exception to this is the occurrence of barite deposits in the Palaeoarchean (3.5-3.2 Ga) which indicate spatial or temporal increases in sulfate concentration. The origin and extent of these enrichments remains controversial and has been difficult to assess due to limited and highly variable data. Here we compile an extensive new database of SIMS multiple sulfur isotope data for pyrite and barite from across the Barberton Greenstone Belt in South Africa in order to further investigate the extent and origin of any sulfate enrichment. Individual pyrites were measured with good stratigraphic and petrographic control. Pyrite δ56Fe was used to further delineate pyrite populations and pathways of pyrite formation. Our new sulfur isotope data support conventional models where a positive Δ33S was derived from heterogeneous photolytic elemental S, with negative Δ33S capturing a homogenized marine sulfate reservoir. Pyrite multiple S isotope data closely track the abundance of barite, suggesting that marine sulfate levels were generally low and that sulfate increases were sporadic and localized. We speculate that the subsequent Neoarchean scarcity was controlled by biological evolution.

  7. Inner radiation belt source of helium and heavy hydrogen isotopes

    Science.gov (United States)

    Leonov, A. A.; Galper, A. M.; Koldashov, S. V.; Mikhailov, V. V.; Casolino, M.; Picozza, P.; Sparvoli, R.

    Nuclear interactions between inner zone protons and atoms in the upper atmosphere provide the main source of energetic H and He isotopes nuclei in the radiation belt. This paper reports on the specified calculations of these isotope intensities using various inner zone proton intensity models (AP-8 and SAMPEX/PET PSB97), the atmosphere drift-averaged composition and density model MSIS-90, and cross-sections of the interaction processes from the GNASH nuclear model code. To calculate drift-averaged densities and energy losses of secondaries, the particles were tracked in the geomagnetic field (modelled through IGRF-95) by integrating numerically the equation of the motion. The calculations take into account the kinematics of nuclear interactions along the whole trajectory of trapped proton. The comparison with new data obtained from the experiments on board RESURS-04 and MITA satellites and with data from SAMPEX and CRRES satellites taken during different phases of solar activity shows that the upper atmosphere is a sufficient source for inner zone helium and heavy hydrogen isotopes. The calculation results are energy spectra and angular distributions of light nuclear isotopes in the inner radiation belt that may be used to develop helium inner radiation belt model and to evaluate their contribution to SEU (single event upset) rates.

  8. Structural setting of the Apennine-Maghrebian thrust belt

    Institute of Scientific and Technical Information of China (English)

    PieroElter; MarioGrasso; MaurizioParotto; LivioVezzani

    2003-01-01

    The Apennine-Maghrebian fold-and-thrust belt devel-oped from the latest Cretaceous to Early Pleistocene at the subduction-collisional boundary between the Euro-pean and the westward-subducted Ionian and Adria plates. Large parts of the Mesozoic oceanic lithosphere were subducted during an Alpine phase from the Late Cretaceous to Middle Eocene. The chain developed through the deformation of major paleogeographic internal domains (tectono-sedimentary sequences of the Ligurian-Piedmont Ocean) and external domains (sedi-mentary sequences derived from the deformation of the continental Adria-African passive mareinL The continu-ity of the Apennine chain is abruptly interrupted in the Calabrian Arc by the extensive klippe of Kabylo-Calabrian crystalline exotic terranes, derived from deformation of the European passive margin.Major complexities (sharp deflections in the arcuate configuration of the thrust belt, out-of-sequence propagation of the thrusts) are referred to contrasting rheology and differential buoyancy of the subducted lithosphere (transitional from conti-nental to oceanic) and consequent differential roll-back of the Adria plate margin, and to competence contrasts in the Mesozoic stratigraphic sequences,where multiple décollement horizons at different stratigraphic levels may have favored significant differential shortening.From the Late Miocene, the geometry of the thrust belt was strongly modified by extensional fault-ing, volcanic activity, crustal thinning and formation of oceanic crust correlated with the development of the Tyrrhenian Basin.

  9. Investigating radiation belt losses though numerical modelling of precipitating fluxes

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2004-11-01

    Full Text Available It has been suggested that whistler-induced electron precipitation (WEP may be the most significant inner radiation belt loss process for some electron energy ranges. One area of uncertainty lies in identifying a typical estimate of the precipitating fluxes from the examples given in the literature to date. Here we aim to solve this difficulty through modelling satellite and ground-based observations of onset and decay of the precipitation and its effects in the ionosphere by examining WEP-produced Trimpi perturbations in subionospheric VLF transmissions. In this study we find that typical Trimpi are well described by the effects of WEP spectra derived from the AE-5 inner radiation belt model for typical precipitating energy fluxes. This confirms the validity of the radiation belt lifetimes determined in previous studies using these flux parameters. We find that the large variation in observed Trimpi perturbation size occurring over time scales of minutes to hours is primarily due to differing precipitation flux levels rather than changing WEP spectra. Finally, we show that high-time resolution measurements during the onset of Trimpi perturbations should provide a useful signature for discriminating WEP Trimpi from non-WEP Trimpi, due to the pulsed nature of the WEP arrival.

  10. An Experimental Concept for Probing Nonlinear Radiation Belt Physics

    Science.gov (United States)

    Amatucci, Bill; Ganguli, Guru; Crabtree, Chris; Mithaiwala, Manish; Siefring, Carl; Tejero, Erik

    2014-10-01

    The SMART sounding rocket is designed to probe the nonlinear response of a known ionospheric stimulus. High-speed neutral barium atoms generated by a shaped charge explosion perpendicular to the magnetic field in the ionosphere form a ring velocity distribution of photo-ionized Ba+ that will generate lower hybrid waves. Induced nonlinear scattering of lower hybrid waves into whistler/magnetosonic waves has been theoretically predicted, confirmed by simulations, and observed in the lab. The effects of nonlinear scattering on wave evolution and whistler escape to the radiation belts have been studied and observable signatures quantified. The fraction of the neutral atom kinetic energy converted into waves is estimated at 10-12%. SMART will carry a Ba release module and an instrumented daughter section with vector wave magnetic and electric field sensors, Langmuir probes and energetic particle detectors to determine wave spectra in the source region and detect precipitated particles. The Van Allen Probes can detect the propagation of the scattered whistlers and their effects in the radiation belts. By measuring the radiation belt whistler energy density, SMART will confirm the nonlinear scattering process and the connection to weak turbulence. Supported by the Naval Research Laboratory Base Funds.

  11. Periodicity in tree rings from the corn belt.

    Science.gov (United States)

    Meko, D M; Stockton, C W; Blasing, T J

    1985-07-26

    Previous tree-ring studies indicated that the total area affected by drought in the western United States has rhythmically expanded and contracted over the past 300 years, with a period near the 18.6-year lunar nodal and 22-year double-sunspot cycles. Recently collected tree-ring data from the U.S. Corn Belt for the years 1680 to 1980 were examined for evidence of either of these cycles on a regional scale. Spectral analysis indicated no periodicity in the eastern part of the Corn Belt, but a significant 18.33-year period in the western part. The period length changed from 17.60 to 20.95 years between the first 150 years and the last 151. High-resolution frequency analysis showed that the structure of the 18.33-year spectral peak was complex, with contributions from several frequencies near both the lunar nodal and double-sunspot periods. A t-test of difference of means in reconstructed annual precipitation weakly corroborated a previous finding of an association between drought area and the phase of the double-sunspot cycle. Both the high-resolution frequency analysis and the t-test results indicate that the periodic component of drought near 20 years is too weak and irregular to be of use in drought forecasting for the Corn Belt.

  12. Detection of Small Kuiper Belt Objects by Stellar Occultations

    CERN Document Server

    Stevenson, R

    2007-01-01

    Knowledge of the Kuiper Belt is currently limited to those objects that can be detected directly. Objects with diameters less than $\\sim$10km reflect too little light to be detected. These smaller bodies could contain most of the mass in the Kuiper Belt while the abundance of these bodies may constrain the distribution of mass. The overall size distribution of bodies within the Kuiper Belt can also be inferred from the relative abundances of sub-km and larger bodies. Stellar occultations are already used to study dark objects in the Solar System, such as asteroids or planetary rings. Occultation by a KBO of a size comparable to, or larger than, that of the Fresnel Scale will result in Fresnel diffraction. Detection of diffraction effects requires fast multiple-star photometry, which will be conducted in July 2007 using the Orthogonal Parallel Transfer Imaging Camera (OPTIC) mounted on the University of Hawaii 2.2m telescope on Mauna Kea. This paper details how knowledge of the mass and structure of the outer ...

  13. Non-Vestoid candidates in the inner Main Belt

    Science.gov (United States)

    Moskovitz, Nicholas; Oszkiewicz, Dagmara; Skiff, Brian; Kankiewicz, Pawel; Licandro, Javier; Galiazzo, Mattia; Zeilinger, Werner

    2016-10-01

    Most Howardite-Eucrite-Diogenite (HED) meteorites (analogues to V-type asteroids) are thought to originate from asteroid (4) Vesta. However some HEDs show distinct oxygen isotope ratios and therefore are thought to originate from other asteroids. In this study we try to identify asteroids that may represent parent bodies of those mismatching HEDs. In particular the origin of the anomalous Bunburra Rockhole meteorite was traced back to the inner main asteroid belt, showing that there might be asteroids that are not genetically linked to the asteroid (4) Vesta (the main source of V-type asteroids and HED meteorites) in the inner main belt. In this work we identify V-type asteroids outside the dynamical Vesta family whose rotational properties (retrograde vs prograde rotation) suggest the direction of Yarkovsky drift that sets them apart from typical Vestoids and Vesta fugitives. Specificly Nesvorny et al. 2008 simulated escapes paths from the Vesta family and showed that typical Vesta fugitives in the inner main asteroid belt at semi-major axis a drift or showing Yarkovsky drift direction towards (4) Vesta are the best candidates for non-Vestoidal V-type asteroids and therefore parent bodies of anomalous HED. In this study we have performed accurate photometric observations and determined sense of rotation for several asteroids testing their links to Vesta and anomalous HED. We have found several potential non-Vestoid candidates. Those objects have to be studied in more detail to fully confirm their link to anomalous HEDs.

  14. Collisional Grooming Models of the Kuiper Belt Dust Cloud

    CERN Document Server

    Kuchner, Marc J

    2010-01-01

    We modeled the 3-D structure of the Kuiper Belt dust cloud at four different dust production rates, incorporating both planet-dust interactions and grain-grain collisions using the collisional grooming algorithm. Simulated images of a model with a face-on optical depth of ~10^-4 primarily show an azimuthally-symmetric ring at 40-47 AU in submillimeter and infrared wavelengths; this ring is associated with the cold classical Kuiper Belt. For models with lower optical depths (10^-6 and 10^-7), synthetic infrared images show that the ring widens and a gap opens in the ring at the location of of Neptune; this feature is caused by trapping of dust grains in Neptune's mean motion resonances. At low optical depths, a secondary ring also appears associated with the hole cleared in the center of the disk by Saturn. Our simulations, which incorporate 25 different grain sizes, illustrate that grain-grain collisions are important in sculpting today's Kuiper Belt dust, and probably other aspects of the Solar System dust c...

  15. Tool Belts: Latitudinal-Belt Predictions for the Persistence of Landscapes

    Science.gov (United States)

    Willenbring, Jane; Brocard, Gilles

    2016-04-01

    The ability of rivers to cut through rock and re-establish equilibrium sets the pace of landscape response to uplift. Because of associations between tectonics, erosion, and weathering, high rates of rock uplift may initiate a cascade of processes that are linked to high rates of weathering and eventually sequestration of CO2 over geologic timescales. How long does it take to completely change the topographic form after uplift and where on Earth do relict landscapes persist despite uplift? Large expanses of subdued landscapes are common at high elevation in mountain ranges. Preservation of subdued fragments amongst steeply dissected regions can therefore be a simple matter of chance, reflecting the time it takes for dissection to remove any remaining parcel of the pre-existing topography after a tectonic perturbation. Some of these relicts may, however, possess characteristics - often a product of the climate - that make them intrinsically resistant to dissection. One common mode of conversion of a subdued landscape into a deeply dissected one is the propagation of upstream-migrating erosion waves that transmit the signal of uplift and base level lowering across entire landscapes. Following a shift in tectonic forcing, the Earth's surface progressively adjusts its topographic form over millions of years, seeking to re-establish equilibrium with the new forcing. Here, we show that a high degree of weathering leading to smaller average soil grains at the surface hinders the capacity of rivers to incise. We show that globally, rates of cosmogenic nuclide-derived denudation rates fall into latitudinal belts with (1) low rates of denudation in areas with high temperatures and high precipitation where rock fragments do not persist at the soil surface, (2) high rates of denudation at mid-latitudes where rock fragments exist and are carried efficiently by the river flow, and (3) low rates of denudation at high latitudes where large grains at the surface inhibit channelized

  16. Structure of the Asteroid Belt from the Gas Giants' Growth and Chaotic Dynamics

    Science.gov (United States)

    Izidoro, André; Raymond, Sean N.; Pierens, Arnaud; Morbidelli, Alessandro; Winter, Othon; Nesvorny, David

    2016-05-01

    The structure of the asteroid belt holds a record of the Solar System's dynamical history. The current belt only contains 10-3 Earth masses yet the asteroids' orbits are dynamically excited, with a large spread in eccentricity and inclination. The belt is also chemically segregated: the inner belt is dominated by dry S-types and the outer belt by hydrated C-types. Here we propose a new model in which the asteroid belt was always low-mass and was partially populated and sculpted by the giant planets on chaotic, resonant orbits. We first show that the compositional dichotomy of the asteroid belt is a simple consequence of Jupiter's growth in the gaseous protoplanetary disk. As Jupiter's core rapidly grew by accreting gas, orbits of nearby planetesimals were perturbed onto Jupiter-crossing trajectories. A significant fraction (~10%) of objects in the neighborhood exterior of Jupiter's orbit were implanted by gas drag into the outer parts of the asteroid belt as C-types. While the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, we show that small perturbations may have driven them into a chaotic but stable state. After the dissipation of the gaseous disk, stochastic variations in the gas giants orbits caused resonances to chaotically jump across the main belt and excite the asteroids' orbits. Our results suggest that the early Solar System was chaotic and introduce a simple framework to understand the origins of the asteroid belt.

  17. The constraints of strain partitioning and geochronology in Luonan-Luanchuan tectonic belts on Qinling orogenic belt

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Luonan-Luanchuan tectonic belt lies between the North China Block and Qinling Mountains, in- cluding the Luonan-Luanchuan fault zone and the strong deformation zone to the north of the fault. The ductile shear zone, imbricate brittle fault and duplex structure in the fault zone now are the expression of the same tectonic event in different depth. Such lineation structure exists in the tectonic belts as mineral lineation, elongation lineation, crenulation lineation, sheath folds and so on, indicating NE-directed plate motion. Fold axes and thrusts in the strong deformation zone are inclined to the Luonan-Luanchuan fault zone at small angles. The structures with different natures show a regular pattern, produced during oblique convergence of plates. The convergence factors are as follows:The direction of plate convergence is 22°, 31° and the angle between the plate convergence direction and plate boundary is 73°, 82° respectively in the west and east segment. The Luonan-Luanchuan tectonic belt was deformed strongly in 372 Ma, resulted from Erlangping back-arc ocean basin subduction sin- istrally and obliquely to North China Block during the collision of North China Block and South China Block.

  18. The constraints of strain partitioning and geochronology in Luonan-Luanchuan tectonic belts on Qinling orogenic belt

    Institute of Scientific and Technical Information of China (English)

    SONG ChuanZhong; ZHANG GuoWei; WANG YongSheng; LI JiaHao; CHEN ZeChao; CAI ZhiChuan

    2009-01-01

    The Luonan-Luanchuan tectonic belt lies between the North China Block and Qinling Mountains,including the Luonan-Luanchuan fault zone and the strong deformation zone to the north of the fault.The ductile shear zone,imbricate brittle fault and duplex structure in the fault zone now are the expression of the same tectonic event in different depth.Such lineation structure exists in the tectonic belts as mineral lineation,elongation lineation,crenulation lineation,sheath folds and so on,indicating NE-directed plate motion.Fold axes and thrusts in the strong deformation zone are inclined to the Luonan-Luanchuan fault zone at small angles.The structures with different natures show a regular pattern,produced during oblique convergence of plates.The convergence factors are as follows:The direction of plate convergence is 22°,31° and the angle between the plate convergence direction and plate boundary is 73°,82° respectively in the west and east segment.The Luonan-Luanchuan tectonic belt was deformed strongly in 372 Ma,resulted from Erlangping back-arc ocean basin subduction sinistrally and obliquely to North China Block during the collision of North China Block and South China Block.

  19. The prevalence of seat belt use in Jamaica. An observational study.

    Science.gov (United States)

    Crandon, I W; Branday, J M; Simeon, D T; Rhoden, A; Thompson, H; Carpenter, R

    1996-03-01

    An observational cross-sectional survey showed that 21.1% of private motor vehicle drivers and 13.5% of front seat passengers voluntarily wore seat belts in Kingston, Jamaica, where there is no law requiring this. Rear passenger utilisation was not examined. Compared to males, females were significantly more likely to wear seat belts when driving but not as front seat passengers. Of all motor vehicles examined, 10.1% were not equipped with seat belts. The oldest group of vehicles were mostly not fitted with seat belts. Drivers of older vehicles were significantly less likely to use seat belts even when the vehicles were equipped with belts. Implementation of legislation can reduce mortality, morbidity and costs from road traffic accidents which are relatively frequent in Jamaica. Male drivers, drivers of older vehicles and all passengers may require specific targeting in an educational and enforcement campaign should legislation, which is highly desirable, be implemented.

  20. Experimental Study of Kinetic Properties of Pyrolysis for Conveyor Belt in Coal Mine

    Institute of Scientific and Technical Information of China (English)

    SONG Zheng-chang

    2005-01-01

    The combustion of conveyor belt is a leading factor of mine fire. In this paper, the pyrolysis properties of ordinary conveyor belt and fire-resistant belt were studied experimentally with thermo-gravimetric analysis and derivative thermo-gravimetric analysis, and the curves of pyrolysis properties were achieved. On this basis, the activation energy and reaction order of pyrolysis were obtained in combination with theoretical analysis, aiming to provide data for further numerical simulation and simulating experiment of mine fire.

  1. Data From HANE-Generated Radiation Belts and the Origin of Diffusion Theory

    Energy Technology Data Exchange (ETDEWEB)

    Winske, Dan [Los Alamos National Laboratory

    2012-07-16

    In this presentation we briefly review some of the published data regarding the artificial radiation belts produced by the Starfish and R2 high altitude nuclear explosions in 1962. The data showed slow temporal variations of the belts in altitude (L) and pitch angle ({alpha}) that could be modeled as a diffusion process. That early work formed the basis for more complex radiation belt diffusion models that are in use at present.

  2. The "One Belt and One Road" is an Important Mutually Beneficial and Win-win Strategy

    Institute of Scientific and Technical Information of China (English)

    Long; Kaifeng

    2015-01-01

    The"One Belt and One Road"strategic conception carries the dream of development and prosperity of countries concerned,and gives the ancient Silk Road a brand new content of the time.In September and October 2013,President Xi Jinping proposed building the"New Silk Road Economic Belt"(One Belt)and the"Twenty-first Century Maritime Silk Road"(One Road)strategic conception respectively,emphasizing a mutual-beneficial and win-win

  3. Progress in porphyry copper exploration from the Gangdise belt, Tibet, China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Youye; DUO Ji; CHENG Shunbo; GAO Shunbao; DAI Fanghua

    2007-01-01

    Recent mineral exploration in the Gangdise porphyry copper deposit belt, an important component of the Himalaya-Tethyan metallogenic belt, has led to the discovery of a number of deposits, as exemplified by the world-class Miocene Qulong porphyry Cu deposit. This paper reviews major advances in the studies of ore genesis and metallogenic regularity and progresses in mineral exploration of porphyry Cu deposits in the belt. Existing problems and suggestion for future exploration also are given.

  4. «Granulite» zircons of the Lapland granulite belt

    Science.gov (United States)

    Kaulina, T.

    2003-04-01

    An age of the main stage of granulite metamorphism, which followed the overthrusting of the Lapland granulite belt (LGB) is estimated at about 1.91-1.95 Ga (Tugarinov, Bibikova, 1980; Bernard-Griffiths et al., 1984; Bibikova et al., 1993; Mitrofanov et al., 1993). This high-grade metamorphism is dated by U-Pb method on short prismatic gem-quality zircons that are typical for granulites and are interpreted as formed under stress and space-shortage conditions of the high pressure. And the common belief is that these zircon ages are dating the peak conditions of a metamorphic P-T path, since zircon has a high closure temperature of its U-Pb system. We studied rocks with different degree of metamorphism from Yavr and Pados rivers district (Kola Peninsula, Russia) located in the connection zone of the Tanaelv belt and LGB. Samples from the Tanaelv belt were taken from: 1) leucocratic garnet-clinopyroxene-amphibole plagiogneiss, chemically corresponds to andesite and formed under amphibolite facies 2) leucocratic biotite-pyroxene plagiogneiss with mineral association of granulite facies. Lapland granulites are represented by sillimanite-garnet-biotite gneiss from khondalite complex and leuco-mesocratic amphibole-pyroxene-plagioschist, belonging to the charnockite complex. Metamorphic zircons in all studied samples are represented practically by crystals of the same image. These are round or isometric (rarely subidiomorphic-prismatic in mafic granulites) large crystals with bright luster and high transparency. They are colorless or weakly colored into yellowish-pinkish tones. Crystals are zoneless but may contain cores, especially zircons from khondalite, 60% of which contain zoned cores. Thus typically “granulitic” zircon, described in many works, is the dominant type both in granulites of the Lapland belt and in amphiboles gneisses of the Tanaelv belt. Zircons are distinguished by low U contents (up to 100 ppm) and high Th/U and Zr/Hf ratios (0.6-0.7 and 42

  5. The Migration Characteristics of Strong Earthquakes on the North-South Seismic Belt and Its Relation with the South Asia Seismic Belt

    Institute of Scientific and Technical Information of China (English)

    Wang Yipeng; Ma Jin; Li Chuanyou

    2008-01-01

    Migration of strong earthquakes (M≥7.0) along the North-South Seismic Belt of China since 1500 AD shows three patterns: Approximately equal time and distance interval migration from N to S, varied patterns of migration from S to N and grouped strong earthquake activity in a certain period over the entire seismic belt. Analysis of strong earthquakes in the past hundred years shows that the seismicity on the North-South Seismic Belt is also associated with strong earthquake activities on the South Asia Seismic Belt which extends from Myanmar to Sumatra, Indonesia. Strong earthquakes on the former belt often lag several months or years behind the quakes occurring on the later belt. So, after the occurrence of the December 26, 2004 M8.7 great earthquake off the western coast of Sumatra, Indonesia, the possibility of occurrence of strong earthquakes on the North-South Seismic Belt of China cannot be ignored. The above-mentioned migration characteristics of strong earthquakes are related to the northeastward collision and subduction of the India Plate as well as the interaction between the Qinghai-Xizang (Tibet) Plateau and the stable and hard Ordos and Alashan Massifs at its northeastern margin.

  6. Geological characteristics and metallogenic prognosis of main gold deposit in Altai gold ore belt, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    SHEN Yuan-chao; SHEN Ping; ZHENG Qing-dong; LIU Tie-bing; LI Guang-ming

    2004-01-01

    Altai polymetallic mineralization belt is famous copper-polymetallic mineralization belt in the world. There are a lot of gold deposits in the Altai ore belt in Xinjiang, China. These gold deposits belong to two genetic types: volcanogene late-stage hydrothermal type and fractured altered rock type. The authors discuss mainly the geological and mineralized features of fractured altered rock type of gold deposits in Altai gold ore belt. Base on this study, the metallogenic law is summarized and the deep metallogenic prognosis has been done in Duolanasayi and Tuokuzibayi gold deposits, and some mineralized anomalys have been discovered.

  7. Triggering Sublimation-driven Activity of Main Belt Comets

    Science.gov (United States)

    Haghighipour, N.; Maindl, T. I.; Schäfer, C.; Speith, R.; Dvorak, R.

    2016-10-01

    It has been suggested that the comet-like activity of main belt comets (MBCs) is due to the sublimation of sub-surface water–ice that has been exposed as a result of their surfaces being impacted by meter-sized bodies. We have examined the viability of this scenario by simulating impacts between meter-sized and kilometer-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle, as well as different target material and water-mass fractions. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m, suggesting that if the activation of MBCs is due to the sublimation of sub-surface water–ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice exposure occurs in the bottom and on the interior surface of impact craters, as well as on the surface of the target where some of the ejected icy inclusions are re-accreted. While our results demonstrate that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, they also indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation, providing more ice for sublimation. We present the details of our simulations and discuss their results and implications.

  8. DREAM3D simulations of inner-belt dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, Gregory Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-26

    A 1973 paper by Lyons and Thorne explains the two-belt structure for electrons in the inner magnetosphere as a balance between inward radial diffusion and loss to the atmosphere, where the loss to the atmosphere is enabled by pitch-angle scattering from Coulomb and wave-particle interactions. In the 1973 paper, equilibrium solutions to a decoupled set of 1D radial diffusion equations, one for each value of the first invariant of motion, μ, were computed to produce the equilibrium two-belt structure. Each 1D radial diffusion equation incorporated an L-and μ-dependent `lifetime' due to the Coulomb and wave-particle interactions. This decoupling of the problem is appropriate under the assumption that radial diffusion is slow in comparison to pitch-angle scattering. However, for some values of μ and L the lifetime associated with pitch-angle scattering is comparable to the timescale associated with radial diffusion, suggesting that the true equilibrium solutions might reflect `coupled modes' involving pitch-angle scattering and radial diffusion and thus requiring a 3D diffusion model. In the work we show here, we have computed the equilibrium solutions using our 3D diffusion model, DREAM3D, that allows for such coupling. We find that the 3D equilibrium solutions are quite similar to the solutions shown in the 1973 paper when we use the same physical models for radial diffusion and pitch-angle scattering from hiss. However, we show that the equilibrium solutions are quite sensitive to various aspects of the physics model employed in the 1973 paper that can be improved, suggesting that additional work needs to be done to understand the two-belt structure.

  9. On the oldest asteroid families in the main belt

    Science.gov (United States)

    Carruba, V.; Nesvorný, D.; Aljbaae, S.; Domingos, R. C.; Huaman, M.

    2016-06-01

    Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects, such as diffusion in mean-motion resonances, Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the time-scales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the late heavy bombardment and that could provide clues on our understanding of the primitive Solar system? In this work, we investigate the dynamical stability of seven of the allegedly oldest families in the asteroid main belt. Our results show that none of the seven studied families has a nominally mean estimated age older than 2.7 Gyr, assuming standard values for the parameters describing the strength of the Yarkovsky force. Most `paleo-families' that formed between 2.7 and 3.8 Gyr would be characterized by a very shallow size-frequency distribution, and could be recognizable only if located in a dynamically less active region (such as that of the Koronis family). V-type asteroids in the central main belt could be compatible with a formation from a paleo-Eunomia family.

  10. Extensive Admixture and Selective Pressure Across the Sahel Belt.

    Science.gov (United States)

    Triska, Petr; Soares, Pedro; Patin, Etienne; Fernandes, Veronica; Cerny, Viktor; Pereira, Luisa

    2015-11-26

    Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).

  11. Single beam optical conveyor belt for chiral particles

    CERN Document Server

    Fernandes, David E

    2016-01-01

    We propose a novel paradigm to selectively manipulate and transport small engineered chiral particles and discriminate different enantiomers using unstructured chiral light. It is theoretically shown that the response of a chiral metamaterial particle may be tailored to enable an optical conveyor belt operation with no optical traps, such that for a fixed incident light helicity and independent of the nanoparticle location, it is either steadily pushed towards the direction of the photon flow or steadily pulled against the photon flow. Our findings create new opportunities for unconventional optical manipulations of tailored nanoparticles and may have applications in sorting racemic mixtures of artificial chiral molecules and in particle delivery.

  12. Accuracy and performance analysis of a nuclear belt weigher

    International Nuclear Information System (INIS)

    Nuclear belt weighers have a broad range of applications in the solid particle industry. This work analyzes the accuracy and sensitivity of nuclear weighers for a wide range of operational conditions and design parameters. The problem of the effect of material profile and bulk density variations on the scale performance is quantitatively addressed. A new methodology is developed to calculate the minimum detectable load accounting for both accuracy and sensitivity. Accuracies of less than 1% can be achieved in some ideal situations by proper design of the source length and geometrical configuration. (orig.)

  13. Ultra low frequency waves impact on radiation belt energetic particles

    Institute of Scientific and Technical Information of China (English)

    ZONG QiuGang; HAO YongQiang; WANG YongFu

    2009-01-01

    One of the most fundamental important issues in the space physics is to understand how solar wind energy transports into the inner magnetosphere.Ultra low frequency(ULF)wave in the magnetosphere and its impact on energetic particles,such as the wave-particle resonance,modulation,and particle acceleration,are extremely important topics in the Earth's radiation belt dynamics and solar windmagnetospheric coupling.In this review,we briefly introduce the recent advances on ULF waves study.Further,we will explore the density structures and ion compositions around the plasmaspheric boundary layer(PBL)and discuss its possible relation to the ULF waves.

  14. Rapid energization of radiation belt electrons by nonlinear wave trapping

    Directory of Open Access Journals (Sweden)

    Y. Katoh

    2008-11-01

    Full Text Available We show that nonlinear wave trapping plays a significant role in both the generation of whistler-mode chorus emissions and the acceleration of radiation belt electrons to relativistic energies. We have performed particle simulations that successfully reproduce the generation of chorus emissions with rising tones. During this generation process we find that a fraction of resonant electrons are energized very efficiently by special forms of nonlinear wave trapping called relativistic turning acceleration (RTA and ultra-relativistic acceleration (URA. Particle energization by nonlinear wave trapping is a universal acceleration mechanism that can be effective in space and cosmic plasmas that contain a magnetic mirror geometry.

  15. Ultra low frequency waves impact on radiation belt energetic particles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    One of the most fundamental important issues in the space physics is to understand how solar wind energy transports into the inner magnetosphere.Ultra low frequency(ULF)wave in the magnetosphere and its impact on energetic particles,such as the wave-particle resonance,modulation,and particle acceleration,are extremely important topics in the Earth’s radiation belt dynamics and solar wind― magnetospheric coupling.In this review,we briefly introduce the recent advances on ULF waves study. Further,we will explore the density structures and ion compositions around the plasmaspheric boundary layer(PBL)and discuss its possible relation to the ULF waves.

  16. Determination of Flutter Derivatives for the Great Belt Bridge

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad; Damsgaard, Aage; Reinhold, Thim A.

    1992-01-01

    A new method which combines control theory and system identification techniques has been used to extract flutter derivatives from section model tests for the Great Belt East Bridge. Tests were conducted by exciting the section model simultaneously in vertical and torsional modes of vibration. Tests...... were primarily conducted in smooth flow for various ratios between vertical and torsional frequencies of vibration. Limited testing was also conducted in turbulent flow and for different angles of attack. The analysis technique described allowed extraction of seven aerodynamic derivatives including...

  17. Horizontal-belt filtration at Randfontein Estates Mine

    International Nuclear Information System (INIS)

    The paper describes tests on horizontal-belt filters for the filtration of gold and uranium. The promising results led to the installation of 17 such filters (ten of them 120 m2 in size) in the mine's metallurgical plants, and their operation is discussed. Although several problems were encountered both in operation and maintenance, it is concluded that, with correct operation and suitable filter cloths, exceptionally good metallurgical recoveries can be achieved at filtration rates twice to three times higher than those on rotary filters

  18. Colloidal Microworms Propelling via a Cooperative Hydrodynamic Conveyor Belt.

    Science.gov (United States)

    Martinez-Pedrero, Fernando; Ortiz-Ambriz, Antonio; Pagonabarraga, Ignacio; Tierno, Pietro

    2015-09-25

    We study propulsion arising from microscopic colloidal rotors dynamically assembled and driven in a viscous fluid upon application of an elliptically polarized rotating magnetic field. Close to a confining plate, the motion of this self-assembled microscopic worm results from the cooperative flow generated by the spinning particles which act as a hydrodynamic "conveyor belt." Chains of rotors propel faster than individual ones, until reaching a saturation speed at distances where induced-flow additivity vanishes. By combining experiments and theoretical arguments, we elucidate the mechanism of motion and fully characterize the propulsion speed in terms of the field parameters. PMID:26451584

  19. Radial diffusion of radiation belt electrons in three dimensions

    Science.gov (United States)

    Perry, Kara Lynn

    It is becoming increasingly important to understand the dynamics of radiation belt energetic particles given their potentially hazardous effects on satellites and our ever-increasing dependence on those satellites. There is a need to determine whether existing two-dimensional models are adequate in estimating the dynamics of the radiation belts or if a three-dimensional model is required. Discussion of general space physics and radiation belt topology is followed by an account of existing models and how these models can be improved by extending dynamic calculations from two dimensions to three. A model is then developed describing magnetic and electric fields associated with poloidal mode Pc5 ULF waves. The frequency and L dependence of the ULF wave power is included in this model by incorporating published ground-based magnetometer data. The influence of ultra low frequency (ULF) waves in the Pc5 frequency range on radiation belt electrons in a dipole magnetic field is examined. This is the first analysis in three dimensions utilizing model ULF wave electric and magnetic fields in the guiding center trajectories of relativistic electrons. It is demonstrated here that realistic spectral characteristics play a significant role in the rate of diffusion of relativistic electrons via drift resonance with poloidal mode ULF waves. Radial diffusion rates including bounce motion are calculated for alphaeq ≥ 50° (lambda ≤ 20°). Energy, L and pitch angle dependence of diffusion rates are calculated for L-independent, L-dependent, frequency independent and frequency dependent field power. During geomagnetic storms when ULF wave power is increased, ULF waves are a significant driver of increased fluxes of relativistic electrons inside geosynchronous orbit. Diffusion time scales obtained here, when frequency and L dependence compared to observations of ULF wave power is included, support this conclusion. A compression is then added to the dipole field model and diffusion

  20. Effective Conveyor Belt Inspection for Improved Mining Productivity

    Energy Technology Data Exchange (ETDEWEB)

    David LaRose

    2006-07-01

    This document details progress on the project ''Effective Conveyor Belt Inspection for Improved Mining Productivity'' during the period from November 15, 2005 to May 14, 2006. Highlights include significant improvements in the accuracy and reliability of computer-vision based vulcanized splice detection, deployment of the vulcanized splice detection algorithms for daily use in two working mines, and successful demonstration of an early prototype of a Smart-Camera based system for on-site mechanical splice detection in coal mine installations.

  1. WFIRST Ultra-Precise Astrometry I: Kuiper Belt Objects

    CERN Document Server

    Gould, Andrew

    2014-01-01

    I show that the WFIRST microlensing survey will enable detection and precision orbit determination of Kuiper Belt Objects (KBOs) down to H_vega=28.2 over an effective area of about 17 square deg. Typical fractional period errors will be ~1.5% X 10^{0.4(H-28.2)} with similar errors in other parameters for roughly 5000 KBOs. Binary companions to detected KBOs can be detected to even fainter limits, H_vega=29, corresponding to R~31 and effective diameters D~7.5 km. This will provide an unprecedented probe of orbital resonance and KBO mass measurements.

  2. Architecture and Channel-Belt Clustering in the Fluvial lower Wasatch Formation, Uinta Basin, Utah

    Science.gov (United States)

    Pisel, J. R.; Pyles, D. R.; Bracken, B.; Rosenbaum, C. D.

    2013-12-01

    The Eocene lower Wasatch Formation of the Uinta Basin contains exceptional outcrops of low net-sand content (27% sand) fluvial strata. This study quantitatively documents the stratigraphy of a 7 km wide by 300 meter thick strike-oriented outcrop in order to develop a quantitative data base that can be used to improve our knowledge of how some fluvial systems evolve over geologic time scales. Data used to document the outcrop are: (1) 550 meters of decimeter to half meter scale resolution stratigraphic columns that document grain size and physical sedimentary structures; (2) detailed photopanels used to document architectural style and lithofacies types in the outcrop; (3) thickness, width, and spatial position for all channel belts in the outcrop, and (4) directional measurements of paleocurrent indicators. Two channel-belt styles are recognized: lateral and downstream accreting channel belts; both of which occur as either single or multi-story. Floodplain strata are well exposed and consist of overbank fines and sand-rich crevasse splay deposits. Key upward and lateral characteristics of the outcrop documented herein are the following. First, the shapes of 243 channels are documented. The average width, thickness and aspect ratios of the channel belts are 110 m, 7 m, and 16:1, respectively. Importantly, the size and shape of channel belts does not change upward through the 300 meter transect. Second, channels are documented to spatially cluster. 9 clusters are documented using a spatial statistic. Key upward patterns in channel belt clustering are a marked change from non-amalgamated isolated channel-belt clusters to amalgamated channel-belt clusters. Critically, stratal surfaces can be correlated from mudstone units within the clusters to time-equivalent floodplain strata adjacent to the cluster demonstrating that clusters are not confined within fluvial valleys. Finally, proportions of floodplain and channel belt elements underlying clusters and channel belts

  3. Nano-optical conveyor belt with waveguide-coupled excitation.

    Science.gov (United States)

    Wang, Guanghui; Ying, Zhoufeng; Ho, Ho-pui; Huang, Ying; Zou, Ningmu; Zhang, Xuping

    2016-02-01

    We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. The feasibility of this design is analyzed using three-dimensional finite-difference time-domain and Maxwell stress tensor methods. Simulation results show that this system is capable of exciting addressable traps and moving particles in a peristaltic fashion with tens of nanometers resolution. It is the first, to the best of our knowledge, report about a nano-optical conveyor belt with waveguide-coupled excitation, which is very important for scalability and on-chip integration. The proposed approach offers a new design direction for integrated waveguide-based optical manipulation devices and its application in large scale lab-on-a-chip integration.

  4. Triggering Sublimation-Driven Activity of Main Belt Comets

    CERN Document Server

    Haghighipour, Nader; Schaefer, Christoph; Speith, Roland; Dvorak, Rudolf

    2016-01-01

    It has been suggested that the comet-like activity of Main Belt Comets are due to the sublimation of sub-surface water-ice that has been exposed as a result of their surfaces being impacted by m-sized bodies. We have examined the viability of this scenario by simulating impacts between m-sized and km-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle as well as different target material and water-mass fraction. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m suggesting that if the activation of MBCs is due to the sublimation of sub-surface water-ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice-exposure occurs in the bottom and on the interior surface of impact craters as well as the surface of the target where some of the ejected icy inclusions...

  5. Study of the NWC electrons belt observed on DEMETER Satellite

    CERN Document Server

    Li, Xinqiao; Wang, Ping; Wang, Huanyu; Lu, Hong; Zhang, Xuemin; Huang, Jianping; Shi, Feng; Yu, Xiaoxia; Xu, Yanbing; Meng, Xiangcheng; Wang, Hui; Zhao, Xiaoyun; Parrot, M

    2010-01-01

    We analyzed the data from 2007 to 2008, which is observed by IDP onboard DEMETER satellite, during ten months of NWC working and seven months of NWC shutdown. The characteristic of the space instantaneous electron belts, which come from the influence of the VLF transmitted by NWC, is studied comprehensively. The main distribution region of the NWC electron belts and the flux change are given. We also studied the distribution characteristic of the average energy spectrum in different magnetic shell at the height of DEMETER orbit and the difference of the average energy spectrum of the electrons in the drift loss-cone between day and night. As a result, the powerful power of NWC transmitter and the 19.8 kHz narrow bandwidth VLF emission not only created a momentary electrons enhancement region, which strides 180 degree in them longitude direction and from 1.6 to 1.9 in L value, with the rise of the electrons flux reaching to 3 orders of magnitude mostly, but also induced the enhancement or loss of electrons in ...

  6. A Method for Determining Sedimentary Micro-Facies Belts Automatically

    Institute of Scientific and Technical Information of China (English)

    Linfu Xue; Qitai Mei; Quan Sun

    2003-01-01

    It is important to understand the distribution of sedimentary facies, especially the distribution of sand body that is the key for oil production and exploration. The secondary oil recovery requires analyzing a great deal of data accumulated within decades of oil field development. At many cases sedimentary micro-facies maps need to be reconstructed and redrawn frequently, which is time-consuming and heavy. This paper presents an integrated approach for determining the distribution of sedimentary micro-facies, tracing the micro-facies boundary, and drawing the map of sedimentary micro-facies belts automatically by computer technique. The approach is based on the division and correlation of strata of multiple wells as well as analysis of sedimentary facies. The approach includes transform, gridding, interpolation, superposing, searching boundary and drawing the map of sedimentary facies belts, and employs the spatial interpolation method and "worm" interpolation method to determine the distribution of sedimentary micro-facies including sand ribbon and/or sand blanket. The computer software developed on the basis of the above principle provides a tool for quick visualization and understanding the distribution of sedimentary micro-facies and reservoir. Satisfied results have been achieveed by applying the technique to the Putaohua Oil Field in Songliao Basin, China.

  7. Finding the Faintest Exozodi and Asteroid Belt Analogs in WISE

    Science.gov (United States)

    Patel, Rahul; Metchev, S.; Heinze, A.

    2014-01-01

    The presence of circumstellar dust in the terrestrial planet zone and asteroid belt regions of stars can be ascertained from the excess flux from main sequence stars in the near to mid-infrared wavelengths. Finding dust in these regions around stars is significant as it traces material related to terrestrial planet formation. In this study, we use the WISE All-Sky Survey data to detect circumstellar debris disks at the 12 and 22 μm bandpasses (W3 and W4, respectively). We present the detection of a sample of over 220 exozodi and asteroid belt analog candidates, 74% of which are brand new detections all at confidence levels >95%. This was done by cross-matching Hipparcos main-sequence stars with the WISE All-Sky Data Release for stars within 75 pc and outside the galactic plane (|b|>5°) and then seeking color excesses at W3 and W4. In addition to applying the standard WISE photometric flags and filters to remove contaminants from our sample, we also improved our selection techniques by correcting for previously unknown systematic behavior in the WISE photometry. Our debris disk candidates are reliable detections as well as unprecedentedly faint, due in large part to these improved selection techniques.

  8. Main-Belt Comet P/2012 T1 (PANSTARRS)

    CERN Document Server

    Hsieh, Henry H; Novakovic, Bojan; Yang, Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Fitzsimmons, Alan; Jedicke, Robert; Kleyna, Jan; Veres, Peter; Wainscoat, Richard J; Ansdell, Megan; Elliott, Garrett T; Keane, Jacqueline V; Meech, Karen J; Moskovitz, Nicholas A; Riesen, Timm E; Sheppard, Scott S; Sonnett, Sarah; Tholen, David J; Urban, Laurie; Kaiser, Nick; Chambers, K C; Burgett, William S; Magnier, Eugene A; Morgan, Jeffrey S; Price, Paul A

    2013-01-01

    We present initial results from observations and numerical analyses aimed at characterizing main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between October 2012 and February 2013 using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research (SOAR) telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 microns that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of QCN100 Myr and is unlikely to be a rec...

  9. Automation of belts; Automatizacion de Cintas de Interior

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This document presents the most important aspects, and the results of the project DEVELOPMENT AND COMMISSIONING OF AN INTEGRATED HAULAGE AND VENTILATION CONTROL SYSTEM IN A MINE USING VERY LONG SUBLEVEL-CAVING WINNING METHOD. Project's targets were to develop, implement and commission a distributed control system for underground mining, which should allow the control and optimisation of the whole (continuous) haulage network. It should also integrate statutory safety features required for both winning and haulage. The system is capable of controlling the most common devices used in underground coal mining transport networks, like conveyor belts, armored conveyors, regulation silos, etc. from the winning faces to the surface, and also the interlocks between them. Moreover, the system implements statutory safety functions for conveyor belt operation, and for mining activities carried out in culls de sac. Specifically, for its relationship with the transport system, it should monitor secondary ventilation, fire damp and toxic gases concentration, and mains power presence in the culls de sac, which have already reached a length of 2000 m. The prototype was installed in the mine that Carbones de Pedraforca owns in Saldes, Barcelona. (Author)

  10. The Distribution of Basaltic Asteroids in the Main Belt

    CERN Document Server

    Moskovitz, Nicholas A; Gaidos, Eric; Willman, Mark; Nesvorny, David; Fevig, Ronald; Ivezic, Zeljko

    2008-01-01

    We present the observational results of a survey designed to target and detect asteroids whose colors are similar to those of Vesta family members and thus may be considered as candidates for having a basaltic composition. Fifty basaltic candidates were selected with orbital elements that lie outside of the Vesta dynamical family. Optical and near-infrared spectra were used to assign a taxonomic type to 11 of the 50 candidates. Ten of these were spectroscopically confirmed as V-type asteroids, suggesting that most of the candidates are basaltic and can be used to constrain the distribution of basaltic material in the Main Belt. Using our catalog of V-type candidates and the success rate of the survey, we calculate unbiased size-frequency and semi-major axis distributions of V-type asteroids. These distributions, in addition to an estimate for the total mass of basaltic material, suggest that Vesta was the predominant contributor to the basaltic asteroid inventory of the Main Belt, however scattered planetesim...

  11. Future Rangeland Ecosystems in the Dryland Belt of Asia

    Science.gov (United States)

    Qi, Jiaguo

    2015-04-01

    One of the greatest challenges humans are facing is sustainably managing water and land resources under changing global environment. This issue is especially pertinent in dryland belt in Asia where freshwater is scarce and shared among many nations. The region is heavily dependent on the diminishing Himalayan glaciers and limited and changing precipitation patterns. With increasing climate variability and a regional warming trend water security issues are acute and if not properly addressed could affect regional stability and lead to international conflicts. Solutions to these urgent regional issues are lacking and further research efforts are needed. Adaptive strategies addressing the complex and multifaceted water resource issues in the region will require a co-design and co-delivery of knowledge specific to the region and must consider exogenous factors such as policies of neighbouring countries and changing precipitation patterns due to climate change. There is a need to determine and fund scientific research priorities and practical approaches co-developed by local stakeholders and scientists to change the region's paradigm to "science for society". This presentation will summarize the collective outcome from a focused group discussion at the international workshop on "Future Earth and Science for Society" to be held from February 25-27, 2015 at Michigan State University, including knowledge gaps, research priorities, a general framework and international collaborations to move forward to addressing the future of the dyrland belt of Asia.

  12. Main-Belt Comet 238P/Read Revisited

    CERN Document Server

    Hsieh, Henry H; Pittichova, Jana

    2011-01-01

    We present a series of observations of the return of activity in main-belt comet 238P/Read. Using data obtained in July and August 2010 when 238P appeared to be largely inactive, we find best-fit IAU phase function parameters of H=19.05+/-0.05 mag, corresponding to a nucleus radius of r_n ~ 0.4 km (assuming an albedo of p_R=0.05), and G=-0.03+/-0.05. Observations from September 2010 onward show a clear rise in activity, causing both a notable change in visible morphology and increasing photometric excesses beyond what would be expected based on bare nucleus observations. By the end of the observing period reported on here, the dust mass in the coma shows indications of reaching a level comparable to that observed in 2005, but further observations are highly encouraged once 238P again becomes observable from Earth in mid-2011 to confirm whether this level of activity is achieved, or if a notable decrease in activity strength compared to 2005 can be detected. Comet 238P is now the second main-belt comet (after ...

  13. Paleoproterozoic postcollisional magmatic belt of the southern Siberian craton

    Science.gov (United States)

    Salnikova, E. B.; Larin, A. M.; Kotov, A. B.; Levitsky, V. I.; Reznitsky, L. Z.; Kovach, V. P.; Yakovleva, S. Z.

    2003-04-01

    Paleoproterozoic time is characterized by large-scale collisional and postcollisional magmatic activity evidenced in the most of ancient cratons. This global event is related to the Arctic supercontinent assemblage (Rogers, 1996). The formation of postcollisional magmatic belt at 1.9-1.8 Ga within the south-west flanking of the Siberian craton is a remarkable example of these processes happened during overall lithospheric convergence. This belt is extends for about 3000 km from the southern Enisey ridge at the west to the central Aldan shield at the east. Within the central Aldan shield the latest collisional event occurred 1925+/-5 Ma (Kotov et al, 2003) and post-collisional subalkaline S- and I-type granites emplaced at 1916+/-10 Ma (Bibikova et al., 1989), 1901+/-1 Ma (Frost et al., 1998) and 1899+/-6 Ma (Kotov et al, 2003). However at the southern Olekma terrain (western Aldan shield) the syncollisional granites have formed at 1906+/-4 Ma and postcollisional Kodar granitoids were generated at 1876-1873 Ma (Larin et al., 2000). The is a tendency outlined in timing of postcollision processes to the west (in modern coordinates). Ages of postcollisional Kevakta granitoid plutons (1846+/-8 Ma) and volcanics of North-Baikal volcano-plutonic belt (1869+/-6 Ma 1856+/-3 Ma), Baikal folded area, support this tendency. Emplacement of the Primorsky complex postcollisional rapakivi-type granitoids (southern Baikal lake) occurred at 1859+/-16 Ma (Donskaya et al., 2002). New results of U-Pb single zircon and baddeleyite dating demonstrate that formation of late-synkinematic syenite, charnockite and pegmatitic veins (1856±12 Ma, 1853±20 Ma) and calciphyre (1868±2 Ma) within the eastern part of the Sharyzhalgay block (southern Baikal lake) occurred virtually within the same episode. Postcollisional intrusive charnockite of the Shumikha complex from the western Sharyzhalgay block dated at 1861±1 Ma (Donskaya et al., 2001) and 1871±17 Ma (Levitsky et al., 2002). Subalcaline

  14. Northwest trending tectonic belt in the middle Yanshan Orogenic Belt of northeast Hebei Province, North China:Tectonic evolution and geochronology

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Changhou; WU; Ganguo; WANG; Genhou; ZHANG; Weijie

    2004-01-01

    The northwest trending tectonic belt in the middle part of the Mesozoic intraplate Yanshan Orogenic Belt, northeast Hebei Province, is composed of thrusts, extensional faults,strike-slip faults and syntectonic sedimentations as well. The northeastward basement-involved major thrusting deformation occurred between 174Ma and 168MaBP and was followed by an intrusion of the granitic plutonic rocks. As a part of the post-thrusting extensional deformations a northwest extending volcano-sedimentation system of Late Jurassic and Early Cretaceous formed in the southwest side of the belt. These volcano-sedimentary sequences are divided into Tuchengzi Formation, Zhangjiakou Formation, Yixian Formation and Jiufotang Formation respectively. They are characterized by southeastward migration as a result of the increasing down-dip slip displacement along the major extensional fault toward the southeast of the belt.The provenance area of the Jiufotang Formation north to it experienced southwestward thrusting during and after its later sedimentation. The thrusting in this stage resulted in the formation of an asymmetric footwall syncline with vergence to SW in the Jiufotang Formation in the NE side of the basin. Finally a dextral strike-slip deformation occurred along the NW tectonic belt. The striking tectono-geomorphological features and present seismic activities along this belt indicate that it has been being active since Cenozoic era and is still in the active state at present. This northwest extending tectonic belt was following the same direction and location as the existing fault systems within the basement as revealed by former geological and geophysical studies. So it is reasonable to infer the Mesozoic deformation along this belt to be a result of reactivation of the basement structures in a favorable tectonic stress field. The reactivation of basement structures might be taken as one of the mechanisms of intraplate deformation and orogeny.

  15. A mathematical analysis of a belt system with a low and time-varying velocity

    NARCIS (Netherlands)

    Suweken, Gede

    2003-01-01

    In this thesis a mathematical analysis has been given for model which describes the transversal vibrations of belt systems. The belt speed is assumed to be time-varying and to be small compared to the wave speed. Not only linear string-like or beam-like models but also nonlinear models have been stu

  16. A Parametric Energy Model for Energy Management of Long Belt Conveyors

    Directory of Open Access Journals (Sweden)

    Tebello Mathaba

    2015-12-01

    Full Text Available As electricity prices continue to rise, the increasing need for energy management requires better understanding of models for energy-consuming applications, such as conveyor belts. Conveyor belts are used in a wide range of industries, including power generation, mining and mineral processing. Conveyor technological advances are leading to increasingly long conveyor belts being commissioned. Thus, the energy consumption of each individual belt conveyor unit is becoming increasingly significant. This paper proposes a generic energy model for belt conveyors with long troughed belts. The model has a two-parameter power equation, and it uses a partial differential equation to capture the variable amount of material mass per unit length throughout the belt length. Verification results show that the power consumption calculations of the newly proposed simpler model are consistent with those of a known non-linear model with an error of less than 4%. The online parameter identification set-up of the model is proposed. Simulations indicate that the parameters can be identified successfully from data with up to 15% measurement noise. Results show that the proposed model gives better predictions of the power consumed and material delivered by a long conveyor belt than the steady-state models in the current literature.

  17. Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt System

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.;

    2013-01-01

    We perform an analysis of the diffuse low-frequency Galactic components in the Southern part of the Gould Belt system (130^\\circ\\leq l\\leq 230^\\circ and -50^\\circ\\leq b\\leq -10^\\circ). Strong ultra-violet (UV) flux coming from the Gould Belt super-association is responsible for bright diffuse...

  18. Thrust Belts and Foreland Basins——SGF/SGE Joint Earth Science Meeting

    Institute of Scientific and Technical Information of China (English)

    Olivier Lacombe; Jér(o)me Lavé; Fran(c)ois Roure

    2006-01-01

    @@ What is the important geologic information that thrust belts and foreland basins have recorded on the erogenic evolution of adjacent mountain belts? How can they reveal the coupled influence of deep (flexure, plate rheology and kinematics) and surficial (erosion, sedimentation) geological processes?

  19. Lithofacies Associations and Depositional Environments of the Neogene Molasse succession, Pishin Belt, northwestern Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal K.; Kassi, Akhtar M.; Friis, Henrik;

    The Pishin Belt is a NE-SW trending mixed flysch and molasse basin, situated at the northwestern part of Pakistan, bordered by Afghan Block of the Eurasian Plate in the west and Indian Plate in the east. Western boundary of the belt is marked by the well-known Chaman Transform Fault, whereas the ...

  20. Illicit Drug Use and the Social Context of HIV/AIDS in Alabama's Black Belt

    Science.gov (United States)

    Lichtenstein, Bronwen

    2007-01-01

    Context: The rural Black Belt of Alabama is among the poorest areas of the nation. Poverty, lack of health infrastructure, and health disparities involving HIV/AIDS and other diseases reflect the lower life expectancy of people in the region. The Black Belt region has the highest HIV rates in rural America. Purpose: Using Alabama as a case…

  1. The sedimentary dynamics in natural and human-influenced delta channel belts

    NARCIS (Netherlands)

    Hobo, N.

    2015-01-01

    This study investigates the increased anthropogenic influence on the within-channel belt sedimentary dynamics in the Rhine delta. To make this investigation, the sedimentary dynamics within the life-cycle of a single channel belt were reconstructed for three key periods of increasing human impact, w

  2. 77 FR 30885 - Clarification of Prior Interpretations of the Seat Belt and Seating Requirements for General...

    Science.gov (United States)

    2012-05-24

    ... Airplane Flight Manual (14 CFR 23.1581(j)). See 36 FR 12511; see also 14 CFR 23.562, 23.785; Legal... 121, part 91 did not require that each person have a separate seat and/or seat belt. See 36 FR 12511... Belt and Seating Requirements for General Aviation Flights AGENCY: Federal Aviation Administration...

  3. Critical taper wedge mechanics of fold-and-thrust belts on Venus - Initial results from Magellan

    Science.gov (United States)

    Suppe, John; Connors, Chris

    1992-01-01

    Examples of fold-and-thrust belts from a variety of tectonic settings on Venus are introduced. Predictions for the mechanics of fold-and-thrust belts on Venus are examined on the basis of wedge theory, rock mechanics data, and currently known conditions on Venus. The theoretical predictions are then compared with new Magellan data.

  4. Triggering Comet-Like Activity of Main Belt Comets

    Science.gov (United States)

    Haghighipour, Nader; Maindl, Thomas I.; Schaefer, Christoph; Speith, Roland; Dvorak, Rudolf

    2016-10-01

    Main-belt comets (MBCs) have attracted a great deal of interest since their identification as activated asteroids by Hsieh and Jewitt in 2006. It has been suggested that the comet-like activity of these objects are due to the sublimation of sub-surface water-ice that has been exposed as a result of their surfaces being impacted by small (e.g, m-sized) bodies. We have examined the viability of this scenario by simulating impacts between m-sized impactors and km-sized targets using a smooth particle hydrodynamics (SPH) approach. We have carried out simulations for a range of impact velocities and angles, material type and strength, and water content of the target allowing m-sized impactors to erode enough of an MBC's surface to trigger its activation. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m suggesting that if the activation of MBCs is due to the sublimation of sub-surface water-ice, this ice has to exist no deeper than a few meters from the surface. Our simulations point to a clearly notable spread in the aggregated crater depths due to different impact energy, impact angles, and MBC's water contents showing deeper craters due to less overall material strength. Results also show that ice-exposure occurs in the bottom and on the interior surface of impact craters as well as the surface of the target where some of the ejected icy inclusions are re-accreted. Our results, in addition to demonstrating that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation. We present details of our simulations and discuss their

  5. Photometry of Main Belt and Trojan asteroids with K2

    Science.gov (United States)

    Szabó, Gyula; Kiss, Csaba; Pal, Andras; Szabo, Robert

    2016-10-01

    Due to the failure of the second reaction wheel, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 Mission, the telescope is staring at the plane of the Ecliptic, hence thousands of Solar System bodies cross the K2 fields, usually causing extra noise in the highly accurate photometric data.We could measure the first continuous asteroid light curves, covering several days wthout interruption, that has been unprecedented to date. We studied the K2 superstamps covering the M35 and Neptune/Nereid fields observed in the long cadence (29.4-min sampling) mode. Asteroid light curves are generated by applying elongated apertures. We investigated the photometric precision that the K2 Mission can deliver on moving Solar System bodies, and determined the first uninterrupted optical light curves of main-belt and Trojan asteroids. We use thed Lomb-Scargle method to find periodicities due to rotation.We derived K2 light curves of 924 main-belt asteroids in the M35 field, and 96 in the path of Neptune and Nereid. Due to the faintness of the asteroids and the high density of stars in the M35 field, 4.0% of the asteroids with at least 12 data points show clear periodicities or trend signalling a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach ˜ 60% in order to successfully recover rotational periods.The derived period-amplitude diagram is consistent to the known distribution of Main Belt asteroids. For Trojan asteroids, the contribution of our 56 objects with newly determined precise period and amplitude is in the order of all previously known asteroids. The comparison with earth-based determinations showed a previous bias toward short periods and has also proven that asteroid periods >20 hour can be unreliable in a few cases because of daylight time and diurnal calibrations. These biases are avoided from the space. We present an unbiased

  6. Periodic responses of a pulley-belt system with one-way clutch under inertia excitation

    Science.gov (United States)

    Ding, Hu

    2015-09-01

    The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley-belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley-belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley-belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency-response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady

  7. The Development of the “One Belt and One Road” and Its Impacts on China-U.S. Relations

    Institute of Scientific and Technical Information of China (English)

    Xia; Liping

    2015-01-01

    In 2013,Chinese President Xi Jinping has taken the initiatives of promoting the"One Belt and One Road".The"One Belt"refers to the Silk Road Economic Belt,and"One Road"to the 21st Century Maritime Silk Road.The"One Belt and One Road"has become one important part of China’s strategy of domestic economic and social development,as well as one important part of China’s foreign strategy.

  8. Inner Radiation Belt Generation of Light Nuclei Isotope

    Science.gov (United States)

    Galper, A. M.; Koldashov, S. V.; Leonv, A. A.; Mikhailov, V. V.

    2003-07-01

    Nuclear interactions between inner zone protons and atoms in the upper atmosphere provide the essential source of H and He isotop es nuclei in radiation belt. This paper reports the calculations of these isotop es intensities from the inner zone proton intensity model AP-8, the atmosphere drift-averaged composition and densities model MSIS-90, and cross sections for the various interaction processes. To calculate drift-averaged densities and energy losses of secondaries the particles are traced in geomagnetic field according IGRF-95 model by numerical solution of motion equation. The calculations account for nuclear interactions kinematic along the whole trapped protons trajectories. The results of calculations are compared with experimental data from SAMPEX, CRRES, RESURS-04 and MITA satellites taken during different solar activity phases. The comparison with observational data shows that the atmosphere is sufficient source for inner zone 4 He, 3 He,2 H and 3 H for L-shell less than 1.3.

  9. A Tropical "NAT-like" belt observed from space

    CERN Document Server

    Chepfer, Hélène; 10.1029/2008GL036289

    2009-01-01

    The optical properties of cold tropical tropopause clouds are examined on a global scale, using two years of space-borne lidar observations from CALIPSO (June 2006 ? May 2008). The linear depolarization ratio, color ratio and backscatter signal are analyzed in tropical clouds colder than 200 K in a way similar to recent studies of Polar Stratospheric Clouds (PSCs). It is found that the three categories of particles encountered in PSC (Ice, Sulfate Ternary Solutions or STS, and Nitric Acid Trihydrate or NAT) do also occur in tropical cold cloud layers. Particles with optical properties similar to NAT are few, but they cover the tropical belt and represent about 20% of cold cloud tropical particles. The optical behavior of these particles requires them to be small, non-spherical, optically thin, and persistent in the TTL at temperatures colder than 200 K; NAT particles and very small ice crystals meet these criteria.

  10. Exploring the Jupiter's and Saturn's radiation belts with LOFAR

    Science.gov (United States)

    Girard, Julien N.; Zarka, Philippe; Pater Imke, de; Hess, Sebastien; Tasse, Cyril; Courtin, Regis; Hofstadter, Mark; Santos-Costa, Daniel; Nettelmann, Nadine; lorenzato, Lise

    2014-05-01

    Since its detection in the mid-fifties, the decimeter synchrotron radiation (DIM), originating from the radiation belts of Jupiter, has been extensively observed over a wide spectrum (from >300 MHz to 22 GHz) by various radio instruments (VLA, ATCA, WSRT, Cassini...). They provided accurate flux measurements as well as resolved maps of the emission that revealed spatial, temporal and spectral variabilities. The strong magnetic field (~4.2 G at the equator) is responsible for the radio emission generated by relativistic electrons. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility configuration (fast rotating 'dipole' magnetic field, beamed radio emission) and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) (e.g. de Pater & Klein, 1989; de Pater & Dunn, 2003; Bagenal (ed.) et al., 2004; Santos-Costa, 2009, 2011). A complete framework is necessary to fully understand the source, loss and transport processes of the electrons populating the inner magnetosphere over a wide frequency range. The low frequencies are associated with electron of lower energies situated in weaker magnetic field regions. LOFAR, the LOw Frequency ARray (LOFAR) (van Haarlem et al., 2012), the last generation of versatile and digital ground-based radio interferometer operates in the [30-250] MHz bandwidth. It brings very high time (~μsec), frequency (~kHz) and angular (~asec) resolutions and huge sensitivities (~mJy). In November 2011, a single 10-hour track enabled to cover an entire planetary rotation and led to image, for the first time, the radiation belts between 127-172 MHz (Girard et al. 2012, 2013). In Feb 2013, an 11-hour joint LOFAR/WSRT observing campaign seized the dyname state of the radiation belts from 45 MHz up to 5 GHz. We will present the current study of the radiation belts

  11. On the oldest asteroid families in the main belt

    CERN Document Server

    Carruba, V; Aljbaae, S; Domingos, R C; Huaman, M

    2016-01-01

    Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects,such as diffusion in mean-motion resonances, Yarkovsky and YORP effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the timescales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the Late Heavy Bombardment and that could provide clues on our understanding of the primitive Solar System? In this work, we investigate the dynamical stability of seven of the allegedly oldest familie...

  12. An on-belt elemental analyser for the cement industry.

    Science.gov (United States)

    Lim, C S; Tickner, J R; Sowerby, B D; Abernethy, D A; McEwan, A J; Rainey, S; Stevens, R; Manias, C; Retallack, D

    2001-01-01

    On-line control of raw mill feed composition is a key factor in the improved control of cement plants. A new and improved on-conveyor belt elemental analyser for cement raw mill feed based on neutron inelastic scatter and capture techniques has been developed and tested successfully in Adelaide Brighton's Birkenhead cement plant on highly segregated material with a depth range of 100 to 180 mm. Dynamic tests in the plant have shown analyser RMS total errors of 0.49, 0.52, 0.38 and 0.23 wt% (on a loss free basis) for CaO, SiO2, Al2O3 and Fe2O3 respectively, when 10-minute counting periods are used. PMID:11144240

  13. Why style matters - uncertainty and structural interpretation in thrust belts.

    Science.gov (United States)

    Butler, Rob; Bond, Clare; Watkins, Hannah

    2016-04-01

    Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

  14. Qinling Orogenic Belt: Its Palaeozoic- Mesozoic Evolution and Metallogenesis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean- Palaeoproterozoic (3.0- 1.6 Ga), (2) plate evolution (0.8- 0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic. The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to extensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic were the main periods of enrichment of large amounts of metals. In the Devonian, many sedex-type massive Pb-Zn- (Cu)-Ag deposits were formed in the hydrothermal basins. In the Triassic (Indosinian-Yanshanian movements), many sediment-hosted disseminated gold deposits and reworked sedimentary type Pb-Zn-Hg-Sb (Au) deposits were formed in the rift hydrothermal basins. Many ductile shear zone-related gold deposits were formed in the restricted ocean basins and residual ocean basins on the two sides of the Qinling micro-plate. The above-mentioned discussion indicates that metallogenesis is not only consistent with geological events, but also controlled by them.

  15. A Path Planning Method for Robotic Belt Surface Grinding

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; YUN Chao

    2011-01-01

    The flexible contact and machining with wide strip are two prominent advantages for the robotic belt grinding system,which can be widely used to improve the surface quality and machining efficiency while finishing the workpieces with sculptured surfaces.There lacks research on grinding path planning with the constraint of curvature.With complicated contact between the contact wheel and the workpiece,the grinding paths for robot can be obtained by the theory of contact kinematics.The grinding process must satisfy the universal demands of the belt grinding technologies,and the most important thing is to make the contact wheel conform to the local geometrical features on the contact area.For the local surfaces with small curvature,the curve length between the neighboring cutting locations becomes longer to ensure processing efficiency.Otherwise,for the local areas with large curvature,the curve length becomes shorter to ensure machining accuracy.A series of planes are created to intersect with the target surface to be ground,and the corresponding sectional profile curves are obtained.For each curve,the curve length between the neighboring cutting points is optimized by inserting a cutter location at the local area with large curvatures.A method of generating the grinding paths including curve length spacing optimization is set up.The validity is completely approved by the off-line simulation,and during the grinding experiments with the method,the quality of surface is improved.The path planning method provides a theoretical support for the smooth and accuracy path of robotic surface grinding.

  16. Inward diffusion and loss of radiation belt protons

    Science.gov (United States)

    Selesnick, R. S.; Baker, D. N.; Jaynes, A. N.; Li, X.; Kanekal, S. G.; Hudson, M. K.; Kress, B. T.

    2016-03-01

    Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (˜103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor ˜2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime ˜120 years.

  17. Two kinds of silicalites in Mount Ailao belt, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two kinds of radiolarian silicalites at the bottom and top of the ophiolite in the Mount (Mt.) Ailao belt, Yunnan Province, are dealt with in this work in terms of geology, micro-paleontology, isotope and REE. The first kind of silicalite was defined as the turbidite formation. In this category, the radiolarian species lived in the Late Devonian (D3). The corresponding ecologic assemblage, composed of δ 30Si (0.4‰-0.5‰, average 0.03‰), δ Ce (0.77- 0.97, average 0.85) and LaN /YbN (0.77-1.06, average 0.96) of silicalite, shows that it occurred in the abyssal environment. The second kind of silicalite was defined as the mud-siliceous formation. Contacting conformably with the basalt of the ophiolite suit, the radiolarian silicalite at the top of ophiolite was in the category of the component units of the ophiolite in the Mt. Ailao belt. In this category, the radiolarian species lived in the Early Carboniferous (C1-). The corresponding ecologic assemblage, composed of d 30Si (0.2‰-1.3‰, averaging 0.7‰), dδCe (0.88- 0.92, averaging 0.90) and LaN /YbN (0.77-1.45, averaging 1.22), of silicalites indicate that it occurred in the bathyal environment. All these facts domonstrate that the Mt. Ailao must have been a small ocean basin at that time.

  18. First ultraviolet reflectance measurements of several Kuiper Belt objects, Kuiper Belt object satellites, and new ultraviolet measurements of A Centaur

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S. A.; Schindhelm, E. [Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302 (United States); Cunningham, N. J., E-mail: astern@swri.edu [Nebraska Wesleyan University, 5000 Saint Paul Avenue, Lincoln, NE 68504 (United States)

    2014-05-01

    We observed the 2600-3200 Å (hereafter, mid-UV) reflectance of two Kuiper Belt Objects (KBOs), two KBO satellites, and a Centaur, using the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). Other than measurements of the Pluto system, these constitute the first UV measurements obtained of KBOs, and KBO satellites, and new HST UV measurements of the Centaur 2060 Chiron. We find significant differences among these objects, constrain the sizes and densities of Haumea's satellites, and report the detection of a possible spectral absorption band in Haumea's spectrum near 3050 Å. Comparisons of these objects to previously published UV reflectance measurements of Pluto and Charon are also made here.

  19. Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt

    Science.gov (United States)

    Mann, I. R.; Ozeke, L. G.; Murphy, K. R.; Claudepierre, S. G.; Turner, D. L.; Baker, D. N.; Rae, I. J.; Kale, A.; Milling, D. K.; Boyd, A. J.; Spence, H. E.; Reeves, G. D.; Singer, H. J.; Dimitrakoudis, S.; Daglis, I. A.; Honary, F.

    2016-10-01

    Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave-particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. Using a data-driven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave-particle scattering loss into the atmosphere is not needed in this case. When rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explained.

  20. Optimizing the Pipe Diameter of the Pipe Belt Conveyor Based on Discrete Element Method

    Science.gov (United States)

    Guo, Yong-cun; Wang, Shuang; Hu, Kun; Li, De-yong

    2016-03-01

    In order to increase the transport volume of the pipe belt conveyor and reduce lateral pressure of the supporting roller set, this study aims to optimize the pipe diameter of the pipe belt conveyor. A mechanical model of the pipe belt conveyor with six supporting roller sets in the belt bearing section was built based on the infinitesimal method, and the formula for calculating the lateral pressure of each supporting roller was deduced on the basis of reasonable assumption. Simulated analysis was carried out on the operation process of the pipe belt conveyor by using the discrete element method. The result showed that, when the other conditions were certain, as the pipe diameter increased, the average lateral pressure of the supporting roller set increased, with a gradually decreasing increment, which was consistent with the calculated result of the theoretical formula. An optimized pipe diameter under the current conditions was obtained by fitting the curve of the formula for calculating the transport volume of the pipe belt conveyor and its simulation curve. It provided a certain reference value for improving the transport efficiency and prolonging the service life of the pipe belt conveyor.

  1. Seat belt syndrome: Delayed or missed intestinal injuries, a case report and review of literature

    Science.gov (United States)

    Al-Ozaibi, Labib; Adnan, Judy; Hassan, Batool; Al-Mazroui, Alya; Al-Badri, Faisal

    2016-01-01

    Introduction Seat belt injuries are not uncommon. The use of seat belts is associated with a unique injury profile collectively termed “the seat belt syndrome”. The aim is to aid in the early diagnosis of seat belt injuries. Case presentation Two different patients presented to the emergency after sustaining a motor vehicle accident. Both were the drivers, restrained and had a frontal impact. On presentation they were hemodynamically stable with mild tenderness on the abdomen and the abdominal computed tomography (CT) did not show any signs of bowel or mesenteric injuries. The signs of peritonitis became obvious after 24 h in one case and after 3 days in the other. Discussion Early diagnosis provides better outcomes for patients with seat belt injuries, but this remains a challenge to trauma surgeons. The typical findings of peritonitis might not be present initially. The presence of abdominal wall ecchymosis (seat belt sign) increases the chance of intraabdominal injuries by eight folds. Conclusion Clinical signs of intestinal injuries might not be obvious on presentation. In the presence of seat belt sign the possibility of bowl injury must be suspected. Admit the patient for observation even if no clinical or radiological findings are present at presentation. PMID:26826929

  2. Metamorphism and plutonism in the Quetico Belt, Superior Province, N.W. Ontario

    Science.gov (United States)

    Percival, J. A.

    1986-01-01

    The Quetico Belt lies between the metavolcanic Wawa-Shebandowan and Wabigoon Belts. It consists of marginal metasedimentary rocks and central pelitic, gneissic and plutonic rocks. Metamorphism is Barrovian, at depths less than 10 km, and grade increases from margins to core of the belt: the outermost pelites are at chlorite-muscovite grade; inward a garnet-andalusite zone formed throughout the inner margin; and the central zone ranges form garnet-andalusite in the west and garnet-sillimanite-muscovite to garnet-sillimanite-cordierite and rare kyanite 6 to 150 km to the east. This increase is correlated with granitic intrusives. Migmatites in the core have intrusive leucosomes in the west and locally derived ones in the east. Isograd surfaces are steep where the belt is narrow and dip gently where it is wide. The Quetico Park intrusive complex of the central region of the Quetico Belt shows a zonation across it 20 to 50 km width from older, medium grained biotite composition to younger, coarse to pegmatitic granitic composition. Sediment of the Quetico basin had its source in the bordering metavolcanic belts and was deposited ca. 2.75 to 2.70 Ga ago. Boundaries of the belt dip inward, so it essentially is a graben of inter-arc or back-arc type.

  3. The Relative Deep Penetrations of Energetic Electrons and Ions into the Slot Region and Inner Belt

    Science.gov (United States)

    Zhao, H.; Li, X.; Claudepierre, S. G.; Fennell, J. F.; Blake, J. B.; Larsen, B.; Skoug, R. M.; Funsten, H. O.; Baker, D. N.; Reeves, G. D.; Spence, H. E.

    2015-12-01

    Energetic electrons in the inner magnetosphere are distributed into two regions: the inner radiation belt and the outer radiation belt, with the slot region in between separating the two belts. Though many studies have focused on the outer belt dynamics, the energetic electrons in the slot region and especially inner belt did not receive much attention until recently. A number of new features regarding electrons in the low L region have been reported lately, including the abundance of 10s-100s of keV electrons in the inner belt, the frequent deep injections of 100s of keV electrons, and 90°-minimum pitch angle distributions of 100s of keV electrons in the inner belt and slot region. In this presentation, we focus on the relative deep injections into the slot region and inner belt of energetic electrons and ions using observations from HOPE and MagEIS instruments on the Van Allen Probes. It is shown that while 10s - 100s of keV electrons penetrate commonly deep into the low L region and are persistent in the inner belt, the deep injections of ions with similar energies occur rarely, possibly due to the fast loss of ions in the low L region. The energy spectra and pitch angle distributions of electrons and ions during injections are also very different, indicating the existence of different physical mechanisms acting on them. In addition, some intriguing similarities between lower energy ions and higher energy electrons will also be discussed.

  4. A method for automated control of belt velocity changes with an instrumented treadmill.

    Science.gov (United States)

    Hinkel-Lipsker, Jacob W; Hahn, Michael E

    2016-01-01

    Increased practice difficulty during asymmetrical split-belt treadmill rehabilitation has been shown to improve gait outcomes during retention and transfer tests. However, research in this area has been limited by manual treadmill operation. In the case of variable practice, which requires stride-by-stride changes to treadmill belt velocities, the treadmill control must be automated. This paper presents a method for automation of asymmetrical split-belt treadmill walking, and evaluates how well this method performs with regards to timing of gait events. One participant walked asymmetrically for 100 strides, where the non-dominant limb was driven at their self-selected walking speed, while the other limb was driven randomly on a stride-by-stride basis. In the control loop, the key factors to insure that the treadmill belt had accelerated to its new velocity safely during the swing phase were the sampling rate of the A/D converter, processing time within the controller software, and acceleration of the treadmill belt. The combination of these three factors resulted in a total control loop time during each swing phase that satisfied these requirements with a factor of safety that was greater than 4. Further, a polynomial fit indicated that belt acceleration was the largest contributor to changes in this total time. This approach appears to be safe and reliable for stride-by-stride adjustment of treadmill belt speed, making it suitable for future asymmetrical split-belt walking studies. Further, it can be incorporated into virtual reality rehabilitation paradigms that utilize split-belt treadmill walking. PMID:26654110

  5. Pb Isotope Mapping in the Tongbai-Dabie Orogenic Belt, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; ZHONG Zengqiu; WANG Linsen; Zhang Benren

    2008-01-01

    Tongbai-Dabie orogenic belt in Central China is a part of the collisional belt between the Yangtze and North China cratons. It represents one of the most extensive ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic rocks in the world. The Pb isotope mapping in this area is a significant method to constrain the crustal structure and tectonic evolution and to identify the tectonic boundaries within the vertical tectonic stack. Based on the Pb isotope compositions of the Dabie complex (DBC), the Tongbai complex (TBC), UHP and HP metamorphic rocks and associated foliated granites, the lower metamorphosed rocks from North Huaiyang (NHY) tectonic belt, and Cretaceous granites in the Tongbai-Dabie orogenic belt, we determined the Pb isotope geochemical map of the Tongbai-Dabie orogenic belt. The Pb isotope map shows that the Pb isotope compositions are similar within each geological body or lithotectonic unit, but the Pb isotope compositions of different lithotectonic units show systematic variations in the Tongbai-Dabie orogenic belt. The NHY tectonic belt contrasts strongly with the Tongbal-Dabie UHP-HP metamorphic belt in Pb isotope compositions.It is suggested that the line along the Xiaotian-Mozitan fault, the north limit of the Tongbai-Dabie UHP and HP metamorphic rocks, represents an important tectonic boundary. Within the Tongbai-Dabie HP -UHP metamorphic belt, to the south of Xiaotian-Mozitan fault, the vertical variations of Pb isotope compositions in different lithotectonic units and the spatial relationship among different major lithotectonic units have been constrained.

  6. Analysis on damage cause of belt eyes for bypass feedwater isolation valves of Daya Bay and Ling'ao NPPs

    International Nuclear Information System (INIS)

    When all of bypass feedwater isolation valves of Daya Bay and Ling'ao NPPs were inspected under disassembled condition, it was found that the belt eyes were damaged in various degrees. The analysis on macro appearance, chemical composition, metallographic, Scanning Electron Microscope and fluid mechanics simulation were carried out on the damaged belt eyes. The results show that the flow rate of belt eye is well above the manufacturer's recommendation so that flow accelerated corrosion and cavitation erosion occur on the belt eyes. According to the damage causes of the belt eyes, corresponding corrective actions are proposed. (authors)

  7. Early Earth tectonics: A high-resolution 3D numerical modelling approach

    Science.gov (United States)

    Fischer, R.; Gerya, T.

    2014-12-01

    Early Earth had a higher amount of remaining radiogenic elements as well as a higher amount of leftover primordial heat. Both contributed to the increased temperature in the Earth's interior and it is mainly this increased mantle potential temperature ΔTp that controls the dynamics of the crust and upper mantle and the style of Early Earth tectonics. For a minor increase in temperature ΔTp buckling, delamination and Rayleigh-Taylor style dripping of the plate is observed in addition. For higher temperatures ΔTp > 250 K no subduction can be observed anymore and tectonics is dominated by delamination and Rayleigh-Taylor instabilities. We conduct 3D petrological-thermomechanical numerical modelling experiments of the crust and upper mantle under Early Earth conditions and a plume tectonics model setup. For varying crustal structures and an increased mantle potential temperature ΔTp, a thermal anomaly in the bottom temperature boundary introduces a plume. The model is able to self-sufficiently form depleted mantle lithosphere after repeated melt removal. New crust can be produced in the form of volcanics or plutonics. To simulate differentiation the newly formed crust can have a range in composition from basaltic over dacitic to granitic depending on its source rock. Models show large amounts of subcrustal decompression melting and consequently large amounts of new formed crust which in turn influences the dynamics. Mantle and crust are convecting separately. Dome-shaped plutons of mafic or felsic composition can be observed in the crust. Between these domes elongated belts of upper crust, volcanics and sediments are formed. These structures look similar to, for example, the Kaapvaal craton in South Africa where the elongated shape of the Barberton Greenstone Belt is surrounded by multiple plutons.

  8. Three Alkali—Rich Intrusive Rock Belts Bewly Discovered in the Mt.Kunlkun—Mt.Altun Region,Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    朱笑青; 王元龙; 等

    2002-01-01

    The newly discovered three alkali-rich intrusive rock belts in the Mt.Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive fock belt, the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beeilisai-Abulash alkali-rich intrusive rock belt.The former two belts were formed during the Yanshanian period,and the third one was formed during the Himalayan period,which is the youngest alkali-rich intrusive rock belt in China.The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.

  9. Three Alkali-Rich Intrusive Rock Belts Newly Discovered in the Mt. Kunlun-Mt. Altun Region, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    朱笑青; 王元龙; 毕华; 王中刚

    2002-01-01

    The newly discovered three alkali-rich intrusive rock belts in the Mt. Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive rock belt,the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beilisai-Abulash alkali-rich intrusive rock belt. The former two belts were formed during the Yanshanian period, and the third one was formed during the Himalayan period, which is the youngest alkali-rich intrusive rock belt in China. The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.

  10. TERRAIN TECTONICS OF THE CENTRAL ASIAN FOLDED BELT

    Directory of Open Access Journals (Sweden)

    M. M. Buslov

    2015-09-01

    Full Text Available The terrain analysis concept envisages primarily a possibility of approximation of fragments / terrains of various geodynamic settings which belong to different plates. The terrain analysis can supplement the theory of plate tectonics in solving problems of geodynamics and tectonics of regions of the crust with complex structures. The Central Asian belt is among such complicated regions. Terrain structures occurred as a result of combined movements in the system of 'frontal' and/or oblique subduction – collision. In studies of geological objects, it is required first of all to prove their (vertical and horizontal autochthony in relations to each other and then proceed to paleogeodynamic, paleotectonic and paleogeographic reconstructions. Obviously, such a complex approach needs data to be obtained by a variety of research methods, including those applied to study geologic structures, stratigraphy, paleontology, paleogeography, lithothlogy, geochemistry, geochronology, paleomagnetism etc. Only by correlating such data collected from inter-disciplinary studies of the regions, it is possible to establish reliable characteristics of the geological settings and avoid mistakes and misinterpretations that may be associated with the 'stratigraphic' approach to solutions of both regional and global problems of geodynamics and tectonics of folded areas. The terrain analysis of the Central Asian folded belt suggests that its tectonic structure combines marginal continental rock complexes that were formed by the evolution of two major oceanic plates. One of them is the plate of the Paleo-Asian Ocean. As the analogue of the current Indo-Atlantic segment of Earth, it is characterised by the presence of continental blocks in the composition of the oceanic crust and the formation of oceanic basins resulting from the breakup of Rodinia and Gondvana. In the course of its evolution, super-continents disintegrated, and the blocks were reunited into the Kazakhstan

  11. New insights into main belt asteroid collisional lifetimes

    Science.gov (United States)

    Henych, Tomas; Holsapple, Keith

    2016-10-01

    We are developing a new Monte Carlo code to study the collisional and spin evolution of main belt asteroids. A byproduct is information on asteroid lifetimes. We find new interpretations and values of those lifetimes.In the conventional approach, the "collisional lifetime" is measured by the time when an asteroid is struck by an impactor large enough to remove one-half of the target's mass. That event is called a catastrophic disruption (CD). From an assumed population of impactors and Poisson statistics, one can estimate the largest expected impactor to impact in a given time interval to get its expected collisional lifetime. However, our Monte Carlo simulations give lifetimes that are distinctly shorter. That raises questions about the basic definition of catastrophic disruption.During its presence in the main belt, many other asteroids of all sizes continually strike a target asteroid. Before the CD one happens, there are many small impacts, and a few less than but not equal to the CD one. Each impact erodes the target asteroid. Very commonly, it is eroded to a much smaller mass before some CD event. We will present examples.So what shall we define as its collisional lifetime? Should it be the time for which its mass is reduced to one-half of its original mass, irrespective of how that happened, perhaps from many impacts? Or when any single impact reduces its mass to one-half of its original mass? Or when a single impact reduces it to one-half of its current mass?We propose that collisional lifetime is defined as the time at which it reaches 50% of its original mass, from any combination of small and/or large events. We use cratering and ejecta scaling formulas (e.g. Holsapple, 1993, Housen and Holsapple, 2011) to calculate the eroded mass history of the target for a history of impactors and calculate the outcome of any impact using the current size. In the gravity regime, the eroded body is easier to disrupt. We will present our lifetime estimates and those of

  12. The absolute magnitude distribution of Kuiper Belt objects

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, Wesley C. [Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Brown, Michael E. [Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Morbidelli, Alessandro [Laboratoire Lagrange, UMR7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d' Azur, BP 4229, F-06304 Nice (France); Parker, Alex [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Batygin, Konstantin, E-mail: wesley.fraser@nrc.ca [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 51, Cambridge, MA 02138 (United States)

    2014-02-20

    Here we measure the absolute magnitude distributions (H-distribution) of the dynamically excited and quiescent (hot and cold) Kuiper Belt objects (KBOs), and test if they share the same H-distribution as the Jupiter Trojans. From a compilation of all useable ecliptic surveys, we find that the KBO H-distributions are well described by broken power laws. The cold population has a bright-end slope, α{sub 1}=1.5{sub −0.2}{sup +0.4}, and break magnitude, H{sub B}=6.9{sub −0.2}{sup +0.1} (r'-band). The hot population has a shallower bright-end slope of, α{sub 1}=0.87{sub −0.2}{sup +0.07}, and break magnitude H{sub B}=7.7{sub −0.5}{sup +1.0}. Both populations share similar faint-end slopes of α{sub 2} ∼ 0.2. We estimate the masses of the hot and cold populations are ∼0.01 and ∼3 × 10{sup –4} M {sub ⊕}. The broken power-law fit to the Trojan H-distribution has α{sub 1} = 1.0 ± 0.2, α{sub 2} = 0.36 ± 0.01, and H {sub B} = 8.3. The Kolmogorov-Smirnov test reveals that the probability that the Trojans and cold KBOs share the same parent H-distribution is less than 1 in 1000. When the bimodal albedo distribution of the hot objects is accounted for, there is no evidence that the H-distributions of the Trojans and hot KBOs differ. Our findings are in agreement with the predictions of the Nice model in terms of both mass and H-distribution of the hot and Trojan populations. Wide-field survey data suggest that the brightest few hot objects, with H{sub r{sup ′}}≲3, do not fall on the steep power-law slope of fainter hot objects. Under the standard hierarchical model of planetesimal formation, it is difficult to account for the similar break diameters of the hot and cold populations given the low mass of the cold belt.

  13. The Main Asteroid Belt: The Crossroads of the Solar System

    Science.gov (United States)

    Michel, Patrick

    2015-08-01

    Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to

  14. Improved electroacoustic dewatering (EAD) belt press for food products. Phase 3, Technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    Battelle`s electroacoustic dewatering (EAD) process improves the performance of mechanical dewatering processes for several food products (such as corn fiber) by superimposing electric and ultrasonic fields. EAD has the potential to save 0.027 to 0.035 quad/yr energy by 1995 in the food processing industry, which consumed 0.15 to 0.18 quad in 1986. This report covers Phase III for demonstrating the EAD prototype on corn wet milling products (corn fiber and gluten); only Task 1 (prototype preparation and planning) was completed. EAD performance was examined in the laboratory; availability of a test site was examined. The single-roll, postdewatering EAD belt press prototype can accept material predewatered by a screw press, centrifuge, or any other mechanical dewatering device. The two-belt system, utilizing a copper-polymer cathode belt, performed as well as the three-belt system used in Phase II.

  15. Dynamics simulation of the belt conveyor possessing feedback loop during starting

    Institute of Scientific and Technical Information of China (English)

    XI Ping-yuan; ZHANG Hai-tao; LIU Jun

    2005-01-01

    Synthesizing the mechanical models of the belt, the driver and the take-up device, the dynamics model was established on the longitudinal vibration of the overall belt conveyor system with finite elemental method, and S-function simulation block of asynchronous motor owing feedback function was built in Matlab/Simulink software, the simulation block indicates that motor rotation speed and its output moment vary with load and time, and the motor is a dynamic feedback system in working process. The state space block was adopted to express model of the belt. Thus it created simulation model of established dynamic model of overall belt conveyor system with Matlab/Simulink software, and simulates the course of starting by properly setting simulation parameters, and processes data for visualization.

  16. Percentage of Drivers and Front Seat Passengers Wearing Seat Belts, 2012, Region 9 - San Francisco

    Data.gov (United States)

    U.S. Department of Health & Human Services — Source for national data: National Occupant Protection Use Survey (NOPUS), 2012. Source for state data: State Observational Survey of Seat Belt Use, 2012.

  17. CRED REA Fish Team Belt Transect Survey at Kauai, Main Hawaiian Islands, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 7 sites at Kauai in the Main...

  18. CRED REA Fish Team Belt Transect Survey at Ofu-Olosega, American Samoa, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Ofu-Olosega in the...

  19. CRED REA Fish Team Belt Transect Surveys at Maro Reef, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 5 sites at Maro Reef in October,...

  20. CRED REA Fish Team Belt Transect Surveys at Pearl and Hermes Reef, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 17 sites at Pearl Hermes Reef in...

  1. CRED REA Fish Team Belt Transect Surveys at Laysan Island, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Laysan Island in...

  2. CRED REA Fish Team Belt Transect Surveys at French frigate Shoals, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  3. CRED REA Fish Team Belt Transect Surveys at the Midway Atoll, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Midway Atoll in...

  4. Principal Resonance of Parametrically Excited Moving Viscoelastic Belts with Geometrical Nonlinearity

    Institute of Scientific and Technical Information of China (English)

    侯之超; 祖武争

    2004-01-01

    Nonlinear dynamic analysis is performed on moving belts subjected to geometric nonlinearity and initial tension fluctuation.To incorporate more accurately the damping mechanism of belt material, linear viscoelastic models are adopted in a unified form of differential operators.To circumvent high-order differential vibration equation of time-varying coefficients and with gyroscopic and nonlinear terms, where analytical solution is almost impossible, a systematic approach is presented by reforming the motion equation and directly using the method of multiple scales.To exemplify the procedure, the solutions at principal resonance are obtained and their stability conditions are derived for employing a Kelvin-Voigt model to reflect the property of the belt material.The solutions and stability conditions successfully reduce to those for using Kelvin model and elastic model, which validate the present approaches.Numerical simulations highlight the effects of tension fluctuations and translating speeds on the stability of the belt vibration.

  5. Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts

    Science.gov (United States)

    Shprits, Yuri Y.; Drozdov, Alexander Y.; Spasojevic, Maria; Kellerman, Adam C.; Usanova, Maria E.; Engebretson, Mark J.; Agapitov, Oleksiy V.; Zhelavskaya, Irina S.; Raita, Tero J.; Spence, Harlan E.; Baker, Daniel N.; Zhu, Hui; Aseev, Nikita A.

    2016-01-01

    The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes. PMID:27678050

  6. CRED REA Fish Team Belt Transect Surveys at Johnston Island, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Johnston Island in...

  7. Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

    Science.gov (United States)

    Yang, Chang; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.

    2016-08-01

    Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. Here we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. These results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

  8. CRED REA Fish Team Belt Transect Survey at Santa Rosa Bank, Marianas Archipelago, 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Santa Rosa Bank in the...

  9. CRED REA Fish Team Belt Transect Survey at Santa Rosa Reef, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Santa Rosa Reef in the...

  10. CRED REA Fish Team Belt Transect Surveys at Midway Atoll, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Midway Atoll in July,...

  11. CRED REA Fish Team Belt Transect Survey at Rose, American Samoa, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at Rose in the American...

  12. Motivating signage prompts safety belt use among drivers exiting senior communities.

    Science.gov (United States)

    Cox, B S; Cox, A B; Cox, D J

    2000-01-01

    Senior drivers are vulnerable to automobile crashes and subsequent injury and death. Safety belts reduce health risks associated with auto crashes. Therefore, it is important to encourage senior drivers to wear safety belts while driving. Using an AB design, replicated five times, we evaluated the short- and long-term effects of a sign with the message "BUCKLE UP, STAY SAFE" attached to a stop sign at the exits of five different senior communities. Safety belt use was stable during two pretreatment assessments averaged across the five sites and 250 drivers (72% and 68% usage), but significantly increased following installation of these signs (94% usage). Six months after installation of the signs, the effect persisted (88% usage). Use of such signs may be a cost-effective way of promoting safety belt use.

  13. CRED REA Fish Team Belt Transect Survey at Midway, NW Hawaiian Islands, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Midway in the NW...

  14. Watershed regressions for pesticides (WARP) for predicting atrazine concentration in Corn Belt streams

    Science.gov (United States)

    Stone, Wesley W.; Gilliom, Robert J.

    2011-01-01

    Watershed Regressions for Pesticides (WARP) models, previously developed for atrazine at the national scale, can be improved for application to the U.S. Corn Belt region by developing region-specific models that include important watershed characteristics that are influential in predicting atrazine concentration statistics within the Corn Belt. WARP models for the Corn Belt (WARP-CB) were developed for predicting annual maximum moving-average (14-, 21-, 30-, 60-, and 90-day durations) and annual 95th-percentile atrazine concentrations in streams of the Corn Belt region. All streams used in development of WARP-CB models drain watersheds with atrazine use intensity greater than 17 kilograms per square kilometer (kg/km2). The WARP-CB models accounted for 53 to 62 percent of the variability in the various concentration statistics among the model-development sites.

  15. The WISE Survey of the Albedo Distribution of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, J.; Mainzer, A.; Grav, T.; Delbó, M.; Mueller, M.; WISE Team, [No Value

    2010-01-01

    Using date from the Wide-field Infrared Survey Explorer (WISE) we investigate the albedo distribution across the main belt of asteroids. When complete WISE will measure albedos and diameters for ~100,000 asteroids.

  16. The Contraction/Expansion History of Charon with implication for its Planetary Scale Tectonic Belt

    CERN Document Server

    Malamud, Uri; Schubert, Gerald

    2016-01-01

    The New-Horizons mission to the Kuiper Belt has recently revealed intriguing features on the surface of Charon, including a network of chasmata, cutting across or around a series of high topography features, conjoining to form a belt. It is proposed that this tectonic belt is a consequence of contraction/expansion episodes in the moon's evolution associated particularly with compaction, differentiation and geophysical reactions of the interior. The proposed scenario involves no need for solidification of a vast subsurface ocean and/or a warm initial state. This scenario is based on a new, detailed thermo-physical evolution model of Charon that includes multiple processes. According to the model, Charon experiences two contraction/expansion episodes in its history that may provide the proper environment for the formation of the tectonic belt. This outcome remains qualitatively the same even if we assume a different initial composition and mass. Two alternative explanations for the precise localization and orie...

  17. CRED REA Fish Team Belt Transect Survey at Pathfinder Reef, Marianas Archipelago, 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Pathfinder Reef in the...

  18. CRED REA Fish Team Belt Transect Survey at Baker, Pacific Remote Island Areas in 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 4 sites at Baker in the Pacific...

  19. CRED REA Fish Team Belt Transect Survey at Ta'u, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Ta'u Islands in...

  20. Poleward expansion of the tropical belt derived from upper tropospheric water vapour

    OpenAIRE

    You, Qinglong; Min, Jinzhong; Kang, Shichang; Pepin, Nick

    2015-01-01

    Based on intersatellite-calibrated high-resolution infrared radiation sounder (HIRS) upper tropospheric water vapour (UTWV) brightness temperatures, the width of the tropical belt is defined as the distance between the latitudes at which maximum HIRS UTWV brightness temperatures are recorded in both hemispheres. Poleward expansion of the tropical belt is evident during 1979–2013 on an annual basis, with an average global magnitude of 1.57° latitude per decade. Most rapid widening is evident i...

  1. EFFECTS OF BELT SPEED, PRESSURE AND GRIT SIZE ON THE SANDING OF Pinus elliottii WOOD

    OpenAIRE

    Manoel Cléber de Sampaio Alves; Luiz Fernando Frezzatti Santiago; Marcos Tadeu Tiburcio Gonçalves; Ivaldo De Domênico Valarelli; Francisco Mateus Faria de Almeida Varasquim

    2015-01-01

    The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size) on the output parameters (temperature and surface roughness) for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD). The results were...

  2. Organochlorine and organophosphorus pesticide residues in fodder and milk samples along Musi river belt, India

    OpenAIRE

    Korrapati Kotinagu; Nelapati Krishnaiah

    2015-01-01

    Aim: The present study was conducted to find the organochlorine pesticide (OCP) and organophosphorus pesticide (OPP) residues in fodder and milk samples along Musi river belt, India. Materials and Methods: Fodder and milk samples collected from the six zones of Musi river belt, Hyderabad India were analyzed by gas chromatography with electron capture detector for OCP residues and pulsated flame photometric detector for the presence of OPP residues. Results: The gas chromatographic analysis of...

  3. MEASURING RESULTS NUMERAL TREATMENT OF IMPULSIVE CURRENTS BY MEANS OF ROGOVSKY BELT APPLICATION

    Directory of Open Access Journals (Sweden)

    U. Batygin

    2009-01-01

    Full Text Available The technique of numerical processing of measurement results of pulse currents by means of Rogovsky belt application is offered in the given work. It is shown that at measurement of signals by digital oscillographs and further numerical transformation of target signals, the possibilities of Rogovsky belt without the application of additional devices that in turn allows to define parameters of pulse currents with any peak-time characteristics essentially expand.

  4. The New Horizons Pluto Kuiper belt Mission: An Overview with Historical Context

    OpenAIRE

    Stern, S. Alan

    2007-01-01

    NASA's New Horizons (NH) Pluto-Kuiper belt (PKB) mission was launched on 19 January 2006 on a Jupiter Gravity Assist (JGA) trajectory toward the Pluto system for a 14 July 2015 closest approach; Jupiter closest approach occurred on 28 February 2007. It was competitively selected by NASA for development on 29 November 2001. New Horizons is the first mission to the Pluto system and the Kuiper belt; and will complete the reconnaissance of the classical planets. The ~400 kg spacecraft carries sev...

  5. The Physiologic Responses of Dutch Belted Rabbits Infected with Inhalational Anthrax

    OpenAIRE

    Lawrence, William S.; Hardcastle, Jason M; Brining, Douglas L; Weaver, Lori E; Ponce, Cindy; Whorton, Elbert B.; Johnny W. Peterson

    2009-01-01

    Bacillus anthracis, the causative agent of anthrax, is a category A priority pathogen that causes extensive damage in humans. For this reason, B. anthracis has been the focus of numerous studies using various animal models. In this study, we explored physiologic parameters in Dutch belted rabbits with inhalation anthrax to characterize the disease progression in this model. To this end, we infected Dutch belted rabbits with 100 LD50 B. anthracis Ames spores by nasal instillation and continuou...

  6. Measurement and monitoring of electrocardiogram belt tension in premature infants for assessment of respiratory function

    Directory of Open Access Journals (Sweden)

    Hegyi Thomas

    2007-04-01

    Full Text Available Abstract Background Monitoring of the electrocardiogram (ECG in premature infants with conventional adhesive-backed electrodes can harm their sensitive skin. Use of an electrode belt prevents skin irritation, but the effect of belt pressure on respiratory function is unknown. A strain gauge sensor is described which measures applied belt tension. Method The device frame was comprised of an aluminum housing and slide to minimize the device weight. Velcro tabs connected housing and slide to opposite tabs located at the electrode belt ends. The slide was connected to a leaf spring, to which were bonded two piezoresistive transducers in a half-bridge circuit configuration. The device was tested for linearity and calibrated. The effect on infant respiratory function of constant belt tension in the normal range (30 g–90 g was determined. Results The mechanical response to a step input was second order (fn = 401 Hz, ζ = 0.08. The relationship between applied tension and output voltage was linear in the range 25–225 gm of applied tension (r2 = 0.99. Measured device sensitivity was 2.18 mV/gm tension using a 5 V bridge excitation voltage. When belt tension was increased in the normal range from 30 gm to 90 gm, there was no significant change in heart rate and most respiratory functions during monitoring. At an intermediate level of tension of 50 gm, pulmonary resistance and work of breathing significantly decreased. Conclusion The mechanical and electrical design of a device for monitoring electrocardiogram electrode belt tension is described. Within the typical range of application tension, cardiovascular and respiratory function are not substantially negatively affected by electrode belt force.

  7. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction

    OpenAIRE

    Rebecca Gyawu; Quansah, Joseph E.; Souleymane Fall; Gichuhi, Peter N; Bovell-Benjamin, Adelia C

    2015-01-01

    In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs) were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%), restaurants (19.7%), fast food restaurants (16.4%), small supermarkets (8.2%), and large supermarket and farmers' markets (3.3 %), respectively. Although there we...

  8. Aeromagnetic and aeromagnetic-based geologic maps of the Coastal Belt, Franciscan Complex, northern California

    Science.gov (United States)

    Langenheim, V.E.; Jachens, R.C.; McLaughlin, R.J.

    2011-01-01

    The Coastal belt of the Franciscan Complex represents a Late Cretaceous to Miocene accretionary prism and overlying slope deposits. Its equivalents may extend from the offshore outer borderland of southern California to north of the Mendocino Triple Junction under the Eel River Basin and in the offshore of Cascadia. The Coastal belt is exposed on land in northern California, yet its structure and stratigraphy are incompletely known because of discontinuous exposure, structural disruption, and lithologically non-distinctive clastic rocks. The intent of this report is to make available, in map form, aeromagnetic data covering the Coastal belt that provide a new dataset to aid in mapping, understanding, and interpreting the incompletely understood geology and structure in northern California. The newly merged aeromagnetic data over the Coastal belt of the Franciscan Complex reveal long, linear anomalies that indicate remarkably coherent structure within a terrane where mapping at the surface indicates complex deformation and that has been described as "broken formation" and, even locally as "melange". The anomalies in the Coastal belt are primarily sourced by volcanic-rich graywackes and exotic blocks of basalt. Some anomalies along the contact of the Coastal belt with the Central belt are likely caused by local interleaving of components of the Coast Ranges ophiolite. These data can be used to map additional exotic blocks within the Coastal belt and to distinguish lithologically indistinct graywackes within the Coastal terrane. Using anomaly asymmetry allows projection of these "layers" into the subsurface. This analysis indicates predominant northeast dips consistent with tectonic interleaving of blocks within a subduction zone.

  9. Optimal linear filters for radiometric transport belt balances

    International Nuclear Information System (INIS)

    Due to a very short measuring path, dynamic measurement can be performed with the radiometric transport band balance. The stochastic perturbations of the measured signal afford the use of adequate filter algorithms. In the case of highly dynamical measurements it may even become necessary to improve the dynamics of the drive system. With essential improvements, the loading measurements can be performed far in front of the belt discharge location. For this purpose a solution is developed on the basis of an optimal control loop synthesis. A simpler solution is based on the optimal choise of the measuring point in order to compensate partially for the inertance of the drive. In addition a linear filter is used to process the radiometric signals. For the optimal design of this filter a method is used, which allows to limit the pulse response to a final time interval. As a consequence, analytical equations can be deduced for the calculation and discussion of the expected filter characteristic. (orig./DG)

  10. Interpreting the Densities of the Kuiper Belt's Dwarf Planets

    CERN Document Server

    Barr, Amy C

    2016-01-01

    Kuiper Belt objects with absolute magnitude less than 3 (radius $\\gtrsim$500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g/cm$^3$. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent ...

  11. Uraniferous mineralizations in the Kuusamo Schist Belt, northeastern Finland

    International Nuclear Information System (INIS)

    The Kouveraara Co-Cu-Au mineralization was found in 1982 with the aid of a geophysical ground survey. This survey was connected with research on the Kouvervaara uranium mineralization in the Early Proterozoic Kuusamo Schist Belt, located just south of the Arctic Circle. In further work, using the Kouvervaara sulphide mineralization as a reference, six Co and Au bearing sulphide mineralizations were discovered, with the help of low altitude aerial geophysical techniques. The Co-Au mineralizations, hosted by the Sericite Quartzite Formation, occur within the hydrothermally altered zones. These zones consist of chloritization, carbonatization, sulphidization, sericitization and albitization, the latter being the most extensive. Excluding the Juomasuo mineralization, uranium is only a trace element in these mineralizations. Other characteristic trace elements are molybdenum and tungsten. The Sivakkaharju and Konttiaho Co-Au-U-Mo mineralizations were found by radiometric ground surveys carried out in 1985 and 1986. These hydrothermal mineralizations occur within brecciated quartz-albite-carbonate rocks and are good manifestations of the positive correlation between uranium and gold in the Kuusamo area. Compared with the other sulphide mineralizations, the Au, U, and Mo contents are remarkably high. Genetically, the mineralizations in the Kuusamo area are associated with deep seated fracture and fault zones, controlled by ancient intracontinental hot spot activity and continental rifting. (author). 31 refs, 6 figs, 2 tabs

  12. Structural style of the Marathon thrust belt, West Texas

    Science.gov (United States)

    Hickman, Robert G.; Varga, Robert J.; Altany, Robert M.

    2009-09-01

    The Marathon portion of the Ouachita thrust belt consists of a highly deformed allochthonous wedge of Cambrian-Pennsylvanian slope strata (Marathon facies) that was transported to the northwest and emplaced over Pennsylvanian foredeep sediments. The foredeep strata in turn overlie early-middle Paleozoic shelfal sediments which are deformed by late Paleozoic basement-involved reverse faults. The Dugout Creek thrust is the basal thrust of the allochthon. Shortening in this sheet and overlying sheets is ˜80%. Steep imbricate faults link the Dugout Creek thrust to upper level detachments forming complex duplex zones. Progressive thrusting and shortening within the allochthon folded the upper level detachments and associated thrust sheets. The Caballos Novaculite is the most competent unit within the Marathon facies and controlled development of prominent detachment folds. Deeper imbricate sheets composed of the Late Pennsylvanian foredeep strata, and possibly early-middle Paleozoic shelfal sediments developed concurrently with emplacement of the Marathon allochthon and folded the overlying allochthon. Following termination of thrusting in the earliest Permian, subsidence and deposition shifted northward to the Delaware, Midland and Val Verde foreland basins.

  13. Belted kingfishers as ecological monitors of contamination: A review

    Energy Technology Data Exchange (ETDEWEB)

    Landrum, C.L. [North Texas Univ., Denton, TX (United States). Dept. of Biology; Ashwood, T.L.; Cox, D.K. [Oak Ridge National Lab., TN (United States)

    1993-03-01

    Aquatic systems serve as transport pathways and reservoirs for most of the contaminants known to be present on the Oak Ridge Reservation (ORR). Organisms that live in aquatic systems accumulate some of these contaminants from their food and directly from the water or sediment. A wide array of terrestrial organisms feeds on aquatic organisms and may accumulate contaminants from aquatic prey. The belted kingfisher (Ceryle alcyon) is a piscivorous and territorial avian species that may be a suitable monitor of contaminant accumulation at specific sites on the ORR. A kingfisher collected on White Oak Lake in 1991 had a {sup 137}Cs concentration of 568 pCi/g in muscle tissue, which exceeds levels found in any other waterfowl collected from the lake. An investigation into the efficacy of using the kingfisher as an ecological indicator of aquatic contaminants on the ORR was initiated in late August 1992. The primary objective of this study was to acquire information concerning the ecology of the kingfisher to determine how the species could be used within the framework of the Biological Monitoring and Abatement Program at Oak Ridge National Laboratory (ORNL). A second important objective of the study was to examine the possible somatic and reproductive effects of polychlorinated biphenyls (PCBs), Hg, and various radioactive contaminants on piscivorous birds by reviewing pollution ecology studies conducted on those species.

  14. Earthquake source characteristics along the arcuate Himalayan belt: Geodynamic implications

    Indian Academy of Sciences (India)

    Prosanta Kumar Khan; Md Afroz Ansari; S Mohanty

    2014-07-01

    The occurrences of moderate to large magnitude earthquakes and associated subsurface geological processes were critically examined in the backdrop of Indian plate obliquity, stress obliquity, topography, and the late Tertiary regional tectonics for understanding the evolving dynamics and kinematics in the central part of the Himalayas. The higher topographic areas are likely associated with the zones of depressions, and the lower topographic areas are found around the ridges located in the frontal part of the orogen. A positive correlation between plate and stress obliquities is established for this diffuse plate boundary. We propose that the zone of sharp bending of the descending Indian lithosphere is the nodal area of major stress accumulation which is released occasionally in form of earthquakes. The lateral geometry of the Himalayas shows clusters of seismicity at an angle of ∼20° from the centre part of the arc. Such spatial distribution is interpreted in terms of compression across the arc and extension parallel to the arc. This biaxial deformation results in the development of dilational shear fractures, observed along the orogenic belt, at an angle of ∼20° from the principal compressive stress axis.

  15. Geochronological review of Sambagawa metamorphic belt in Southwest Japan

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on almost all available published age data, the protolith ages, peak metamorphic ages and cooling rate of the Sambagawa metamorphic belt have been discussed and the latest constraints on the ages of the Sambagawa metamorphism and subduction-related accretionary evolutions were summarized. Peak metamorphic conditions attained within the Kuma nappe complex at ca. 145~185 Ma, and uplift through ca. 500℃ at ca. 150 Ma and 350~400℃ at ca. 110~ 115 Ma. The protolith sediments of the Besshi nappe complex were accumulated and subsequently progressively subducted and suffered high P-T prograde metamorphism during the Kuma nappe complex uplifting. The Besshi nappe complex arrived maximum metamorphic conditions at ca. 110 ~ 120 Ma and subsequently started rapid uplift with the cooling rate of ca. 14.2℃/Ma at ca. 75 ~85 Ma, followed with the cooling rate of ca. 6.0 ~8.9℃/Ma. The Oboke nappe complex started subduction later than other tectonic units and arrived the peak metamorphic conditions at ca. 75 Ma, which followed by the uplift with a cooling rate of ca. 8℃/Ma.

  16. The Gould Belt 'MISFITS' Survey: The Real Solar Neighborhood Protostars

    CERN Document Server

    Heiderman, Amanda

    2015-01-01

    We present an HCO$^{+}$ J=3-2 survey of Class 0+I and Flat SED young stellar objects (YSOs) found in the Gould Belt clouds by surveys with Spitzer. Our goal is to provide a uniform Stage 0+I source indicator for these embedded protostar candidates. We made single point HCO$^{+}$ J = 3-2 measurements toward the source positions at the CSO and APEX of 546 YSOs (89% of the Class 0+I + Flat SED sample). Using the criteria from van Kempen et al. (2009), we classify sources as Stage 0+I or bona fide protostars and find that 84% of detected sources meet the criteria. We recommend a timescale for the evolution of Stage 0+I (embedded protostars) of 0.54 Myr. We find significant correlations of HCO$^{+}$ integrated intensity with ${\\alpha}$ and $T_{bol}$ but not with $L_{bol}$. The detection fraction increases smoothly as a function of ${\\alpha}$ and $L_{bol}$, while decreasing smoothly with $T_{bol}$. Using the Stage 0+I sources tightens the relation between protostars and high extinction regions of the cloud; 89% of ...

  17. Volatile Loss and Classification of Kuiper Belt Objects

    CERN Document Server

    Johnson, R E; Young, L A; Volkov, A N; Schmidt, C

    2015-01-01

    Observations indicate that some of the largest Kuiper Belt Objects (KBOs) have retained volatiles in the gas phase, which implies the presence of an atmosphere that can affect their reflectance spectra and thermal balance. Volatile escape rates driven by solar heating of the surface were estimated by Schaller and Brown (2007) (SB) and Levi and Podolak (2009)(LP) using Jeans escape from the surface and a hydrodynamic model respectively. Based on recent molecular kinetic simulations these rates can be hugely in error (e.g., a factor of $\\sim 10^{16}$ for the SB estimate for Pluto). In this paper we estimate the loss of primordial N$_2$ for several large KBOs guided by recent molecular kinetic simulations of escape due to solar heating of the surface and due to UV/EUV heating of the upper atmosphere. For the latter we extrapolate simulations of escape from Pluto (Erwin et al. 2013) using the energy limited escape model recently validated for the KBOs of interest by molecular kinetic simulations (Johnson et al. 2...

  18. Initial highlights from the Herschel Gould Belt survey

    CERN Document Server

    André, Ph; Bontemps, S; Könyves, V; Motte, F; Schneider, N; Didelon, P; Minier, V; Saraceno, P; Ward-Thompson, D; Di Francesco, J; White, G; Molinari, S; Testi, L; Abergel, A; Griffin, M; Henning, Th; Royer, P; Merín, B; Vavrek, R; Attard, M; Arzoumanian, D; Wilson, C D; Ade, P; Aussel, H; Baluteau, J -P; Benedettini, M; Bernard, J -Ph; Blommaert, J A D L; Cambrésy, L; Cox, P; Di Giorgio, A; Hargrave, P; Hennemann, M; Huang, M; Kirk, J; Krause, O; Launhardt, R; Leeks, S; Pennec, J Le; Li, J Z; Martin, P; Maury, A; Olofsson, G; Omont, A; Peretto, N; Pezzuto, S; Prusti, T; Roussel, H; Russeil, D; Sauvage, M; Sibthorpe, B; Sicilia-Aguilar, A; Spinoglio, L; Waelkens, C; Woodcraft, A; Zavagno, A

    2010-01-01

    We summarize the first results from the Gould Belt survey, obtained toward the Aquila Rift and Polaris Flare regions during the 'science demonstration phase' of Herschel. Our 70-500 micron images taken in parallel mode with the SPIRE and PACS cameras reveal a wealth of filamentary structure, as well as numerous dense cores embedded in the filaments. Between ~ 350 and 500 prestellar cores and ~ 45-60 Class 0 protostars can be identified in the Aquila field, while ~ unbound starless cores and no protostars are observed in the Polaris field. The prestellar core mass function (CMF) derived for the Aquila region bears a strong resemblance to the stellar initial mass function (IMF), already confirming the close connection between the CMF and the IMF with much better statistics than earlier studies. Comparing and contrasting our Herschel results in Aquila and Polaris, we propose an observationally-driven scenario for core formation according to which complex networks of long, thin filaments form first within molecul...

  19. Storm/substorm signatures in the outer belt

    International Nuclear Information System (INIS)

    The response of the ring current region is compared for periods of storm and substorm activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and substorm (AE) activity and examine compositional changes. Substorm activity leads to the intensification of the ring current at higher L (L ∼ 6) and lower ring current energies compared to storms (L ∼ 4). The O+/H+ ratio during substorms remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated substorms with an AE ∼ 900 nT lead to a ΔDst of ∼ 30 nT, but do not contribute to Dst during storm main phase as substorm injections do not form a symmetric ring current during such disturbed times

  20. Baseline air quality evaluation for the Venezuelan Orinoco Bitumen Belt

    International Nuclear Information System (INIS)

    To achieve a harmonic relationship between oil exploration and production activities and the environment, Petroleos de Venezuela and its affiliated companies conducted environmental evaluations of the physical and bionic media in the Orinoco Bitumen Belt. This region covers an area of approximately 42000 km2 with estimated bitumen reserves on the order of 3 x 1012 barrels, one of the largest bitumen reservoirs in the world. This paper presents the results of a study of baseline air quality conditions: an emissions inventory, surface and upper layer meteorological conditions and measurements of air quality parameters of interest (CO, HC, NOx, SO2, H2S and T.S.P.) taken by a network of automated air quality stations using standard international reference techniques. The temporal (hourly and daily basis) and spatial air quality variability and the variables/activities that might determine the observed trends are discussed. NO, NO2, SO2 and H2S concentrations were lower than the detection limits of the analytical methods, while O3 and CO 1-hour average levels ranged from 5-30 ppb and 0.5-1.8 ppm, respectively, and T.S.P. daily means varied from 10-50 μg/m3, all of which is close to natural background concentrations. Maximum hourly average reactive hydrocarbon concentrations of 0.37 ppm were found near a producing oil field

  1. Two Color Populations of Kuiper Belt and Centaur Objects

    Science.gov (United States)

    Tegler, Stephen C.; Romanishin, William; Consolmagno, Guy

    2016-10-01

    We present new optical colors for 64 Kuiper belt objects (KBOs) and Centaur objects measured with the 1.8-meter Vatican Advanced Technology Telescope (VATT) and the 4.3-meter Discovery Channel Telescope (DCT). By combining these new colors with our previously published colors, we increase the sample size of our survey to 154 objects. Our survey is unique in that the uncertainties in our color measurements are less than half the uncertainties in the color measurements reported by other researchers in the literature. Small uncertainties are essential for discerning between a unimodal and a bimodal distribution of colors for these objects as well as detecting correlations between colors and orbital elements. From our survey, it appears red Centaurs have a broader color distribution than grey Centaurs. We find red Centaurs have a smaller orbital inclination angle distribution than grey Centaurs at the 99.3% confidence level. Furthermore, we find that our entire sample of KBOs and Centaurs exhibits bimodal colors at the 99.4% confidence level. KBOs and Centaurs with HV > 7.0 have bimodal colors at the 99.96% confidence level and KBOs with HV < 6.0 have bimodal colors at the 96.3% confidence level.We are grateful to the NASA Solar System Observations Program for support, NAU for joining the Discovery Channel Telescope Partnership, and the Vatican Observatory for the consistent allocation of telescope time over the last 12 years of this project.

  2. Mechanism of hydro-viscous soft start of belt conveyor

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-rui; HOU You-fu

    2008-01-01

    The mechanism of a hydro-viscous soft start is of great importance in the design of a hydro-viscous clutch and its control system. To explain the mechanism of a hydro-viscous soft start, the startup process of a belt conveyor was numerically analyzed with the modified Reynolds equation, an energy equation and a temperature-viscosity equation. The effect of temperature and grooves of the friction disk surface on torque transfer and load capacity of the oil film have also been analyzed. The results show that 1) the grooves are the basis of forming dynamic pressure but they may reduce the capacity of torque transfer to a certain extent,2) during the startup process, temperature has little effect on torque transfer and load capacity and the variation in load capacity of the oil film is very small, indicating that it is preferable to use the flow rate as a control object than the pressure of the feed cylinder.The results have been verified by an experiment.

  3. First results from the Herschel Gould Belt Survey in Taurus

    CERN Document Server

    Kirk, J M; Palmeirim, P; Andre, Ph; Griffin, M J; Hargrave, P J; Konyves, V; Bernard, J P; Nutter, D J; Sibthorpe, B; Di Francesco, J; Abergel, A; Arzoumanian, D; Benedettini, M; Bontemps, S; Elia, D; Hennemann, M; Hill, T; Men'shchikov, A; Motte, F; Nguyen-Luong, Q; Peretto, N; Pezzuto, S; Rygl, K L J; Sadavoy, S I; Schisano, E; Schneider, N; Testi, L; White, G

    2013-01-01

    The whole of the Taurus region (a total area of 52 sq. deg.) has been observed by the Herschel SPIRE and PACS instruments at wavelengths of 70, 160, 250, 350 and 500 {\\mu}m as part of the Herschel Gould Belt Survey. In this paper we present the first results from the part of the Taurus region that includes the Barnard 18 and L1536 clouds. A new source-finding routine, the Cardiff Source-finding AlgoRithm (CSAR), is introduced, which is loosely based on CLUMPFIND, but that also generates a structure tree, or dendrogram, which can be used to interpret hierarchical clump structure in a complex region. Sources were extracted from the data using the hierarchical version of CSAR and plotted on a mass-size diagram. We found a hierarchy of objects with sizes in the range 0.024-2.7 pc. Previous studies showed that gravitationally bound prestellar cores and unbound starless clumps appeared in different places on the mass-size diagram. However, it was unclear whether this was due to a lack of instrumental dynamic range ...

  4. Belted kingfishers as ecological monitors of contamination: A review

    International Nuclear Information System (INIS)

    Aquatic systems serve as transport pathways and reservoirs for most of the contaminants known to be present on the Oak Ridge Reservation (ORR). Organisms that live in aquatic systems accumulate some of these contaminants from their food and directly from the water or sediment. A wide array of terrestrial organisms feeds on aquatic organisms and may accumulate contaminants from aquatic prey. The belted kingfisher (Ceryle alcyon) is a piscivorous and territorial avian species that may be a suitable monitor of contaminant accumulation at specific sites on the ORR. A kingfisher collected on White Oak Lake in 1991 had a 137Cs concentration of 568 pCi/g in muscle tissue, which exceeds levels found in any other waterfowl collected from the lake. An investigation into the efficacy of using the kingfisher as an ecological indicator of aquatic contaminants on the ORR was initiated in late August 1992. The primary objective of this study was to acquire information concerning the ecology of the kingfisher to determine how the species could be used within the framework of the Biological Monitoring and Abatement Program at Oak Ridge National Laboratory (ORNL). A second important objective of the study was to examine the possible somatic and reproductive effects of polychlorinated biphenyls (PCBs), Hg, and various radioactive contaminants on piscivorous birds by reviewing pollution ecology studies conducted on those species

  5. Arable weed flora in the Western Siberian grain belt

    Directory of Open Access Journals (Sweden)

    Kämpf, Immo

    2016-02-01

    Full Text Available Between Ekaterinburg and Nowosibirsk, in the Western Siberian grain belt, spring wheat is grown on fertile Chernozem soils. Field and farm sizes are large but the land-use intensity per area is low compared to Central Europe. Fertilizers and pesticides are applied only in low to moderate quantities and yields range between 10 and 20 dt ha-1. We studied the arable weed flora in the northern forest steppe zone of Tyumen region using a randomized sampling design. Surprisingly, the species richness was only moderate, on average 9.8 ± 3.8 species per 100 m². Compared to weed communities of Bashkiria (Southern Ural and less intensively used arable land of Central Europe these numbers are rather low. Moreover, most of the recorded species were cosmopolitans or widely distributed throughout the temperate zone. We suggest that the land use intensity was high enough to reduce the density of a number of weed species in a way that they were not registered by our random sampling design. The limited conservational value of the weed vegetation of large grain fields in Tyumen leads to the conclusion that if intensification of land use is unavoidable, it should be directed to arable land and not to ex-arable land or ancient grassland, which is of higher conservation value.

  6. Size Distribution of Main-Belt Asteroids with High Inclination

    CERN Document Server

    Terai, Tsuyoshi

    2010-01-01

    We investigated the size distribution of high-inclination main-belt asteroids (MBAs) to explore asteroid collisional evolution under hypervelocity collisions of around 10 km/s. We performed a wide-field survey for high-inclination sub-km MBAs using the 8.2-m Subaru Telescope with the Subaru Prime Focus Camera (Suprime-Cam). Suprime-Cam archival data were also used. A total of 616 MBA candidates were detected in an area of 9.0 deg^2 with a limiting magnitude of 24.0 mag in the SDSS r filter. Most of candidate diameters were estimated to be smaller than 1 km. We found a scarcity of sub-km MBAs with high inclination. Cumulative size distributions (CSDs) were constructed using Subaru data and published asteroid catalogs. The power-law indexes of the CSDs were 2.17 +/- 0.02 for low-inclination ( 15 deg) MBAs in the 0.7-50 km diameter range. The high-inclination MBAs had a shallower CSD. We also found that the CSD of S-like MBAs had a small slope with high inclination, whereas the slope did not vary with inclinatio...

  7. Kuiper belt structure around nearby super-Earth host stars

    CERN Document Server

    Kennedy, Grant M; Marmier, Maxime; Greaves, Jane S; Wyatt, Mark C; Bryden, Geoffrey; Holland, Wayne; Lovis, Christophe; Matthews, Brenda C; Pepe, Francesco; Sibthorpe, Bruce; Udry, Stéphane

    2015-01-01

    We present new observations of the Kuiper belt analogues around HD 38858 and HD 20794, hosts of super-Earth mass planets within 1 au. As two of the four nearby G-type stars (with HD 69830 and 61 Vir) that form the basis of a possible correlation between low-mass planets and debris disc brightness, these systems are of particular interest. The disc around HD 38858 is well resolved with Herschel and we constrain the disc geometry and radial structure. We also present a probable JCMT sub-mm continuum detection of the disc and a CO J=2-1 upper limit. The disc around HD 20794 is much fainter and appears marginally resolved with Herschel, and is constrained to be less extended than the discs around 61 Vir and HD 38858. We also set limits on the radial location of hot dust recently detected around HD 20794 with near-IR interferometry. We present HARPS upper limits on unseen planets in these four systems, ruling out additional super-Earths within a few au, and Saturn-mass planets within 10 au. We consider the disc st...

  8. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    CERN Document Server

    Girard, J N; Tasse, C; Hess, S; de Pater, I; Santos-Costa, D; Nenon, Q; Sicard, A; Bourdarie, S; Anderson, J; Asgekar, A; Bell, M E; van Bemmel, I; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Breton, R P; Broderick, J W; Brouw, W N; Brüggen, M; Ciardi, B; Corbel, S; Corstanje, A; de Gasperin, F; de Geus, E; Deller, A; Duscha, S; Eislöffel, J; Falcke, H; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Hessels, J W T; Hoeft, M; Hörandel, J; Iacobelli, M; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Loose, M; Maat, P; Mann, G; Markov, S; McFadden, R; McKay-Bukowski, D; Moldon, J; Munk, H; Nelles, A; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Rowlinson, A; Schwarz, D; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; van Weeren, R J; Wijers, R A M J; Wucknitz, O

    2015-01-01

    Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electrons magnetically trapped around the planet (because in-situ particle data are limited in the inner magnetosphere). Aims. We perform the first resolved and low-frequency imaging of the synchrotron emission with LOFAR at 127 MHz. The radiation comes from low energy electrons (~1-30 MeV) which map a broad region of Jupiter's inner magnetosphere. Methods (see article for complete abstract) Results. The first resolved images of Jupiter's radiation belts at 127-172 MHz are obtained along with total integrated flux densities. They are compared with previous observations at higher frequencies and show a larger extent of the synchrotron emission source (>=4 $R_J$). The asymmetry and the dynamic of east-west emission peaks are measured and the presence of a hot spot at lambda_III=230 {\\deg} $\\pm$ 25 {\\deg}. Spectral flux density measurements ar...

  9. Dynamical delivery of volatiles to the outer main belt

    Science.gov (United States)

    Grazier, Kevin R.; Castillo-Rogez, Julie C.; Sharp, Philip W.

    2014-04-01

    We quantify the relative contribution of volatiles supplied from outer Solar System planetesimal reservoirs to large wet asteroids during the first few My after the beginning of the Solar System. To that end, we simulate the fate of planetesimals originating within different regions of the Solar System - and thus characterized by different chemical inventories - using a highly accurate integrator tuned to handle close planet/planetesimal encounters. The fraction of icy planetesimals crossing the Asteroid Belt was relatively significant, and our simulations show that planetesimals originating from the Jupiter/Saturn region were orders of magnitude more abundant than those stemming from the Uranus and Neptune regions when the planets were just embryos. As the planets reached their full masses the Jupiter/Saturn and Saturn/Uranus regions contributed similar fractions of planetesimals for any material remaining in these reservoirs late in the stage of planetary formation, This implies that large asteroids like Ceres accreted very little material enriched in low-eutectic volatiles (e.g., methanol, nitrogen and methane ices, etc.) and clathrate hydrates expected to condense at the very low temperatures predicted for beyond Saturn’s orbit in current early solar nebula models. Further, a large fraction of the content in organics of Ceres and neighboring ice-rich objects originates from the outer Solar System.

  10. The Roles of Transport and Wave-Particle Interactions on Radiation Belt Dynamics

    Science.gov (United States)

    Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua

    2011-01-01

    Particle fluxes in the radiation belts can vary dramatically during geomagnetic active periods. Transport and wave-particle interactions are believed to be the two main types of mechanisms that control the radiation belt dynamics. Major transport processes include substorm dipolarization and injection, radial diffusion, convection, adiabatic acceleration and deceleration, and magnetopause shadowing. Energetic electrons and ions are also subjected to pitch-angle and energy diffusion when interact with plasma waves in the radiation belts. Important wave modes include whistler mode chorus waves, plasmaspheric hiss, electromagnetic ion cyclotron waves, and magnetosonic waves. We investigate the relative roles of transport and wave associated processes in radiation belt variations. Energetic electron fluxes during several storms are simulated using our Radiation Belt Environment (RBE) model. The model includes important transport and wave processes such as substorm dipolarization in global MHD fields, chorus waves, and plasmaspheric hiss. We discuss the effects of these competing processes at different phases of the storms and validate the results by comparison with satellite and ground-based observations. Keywords: Radiation Belts, Space Weather, Wave-Particle Interaction, Storm and Substorm

  11. On the formation and evolution of asteroid belts and their potential significance for life

    CERN Document Server

    Martin, Rebecca G

    2012-01-01

    Suggestions have been made that asteroid belts may be important both for the existence of life and perhaps even for the evolution of complex life on a planet. Using numerical models for protoplanetary discs we calculate the location of the snow line, and we propose that asteroid belts are most likely to form in its vicinity. We then show that observations of warm dust in exo-solar systems, thought to be produced by collisions between asteroids in a belt, indicate that asteroid belts (when they exist), indeed coincide with the radial location and the temperature of the snow line. Giant planets form outside the snow line and prevent planet formation just inside of their orbit creating an asteroid belt there. However, the migration of giant planets through the asteroid belt likely disperses the compact formation. We examine existing observations of giant exo-planets and find that less than 4% are at radial locations outside of the snow line. This definitely may be the consequence of observational selection effec...

  12. Biomechanical caracterisation of lumbar belt by full-field techniques: Preliminary results

    CERN Document Server

    Bonnaire, Rebecca; Calmels, Paul; Convert, Reynald

    2013-01-01

    In France, 50% of the population per year is suffering from low back pain. Lumbar belt are frequently proposed as a part of the treatment of this pathology. However mechanical ways of working of this medical device is not clearly understood, but abdominal pressure is often related. So an optical method was developed in this study to measure strain in lumbar belt and trunk interface and to derive a pressure estimation. Optical method consisted of coupling fringe projection and digital image correlation (DIC). Measurement has been carried out on the right side of a manikin wearing a lumbar belt. Average strain is 0.2 and average pressure is 1 kPa. Continuation of this study will be comparison of strain and pressure in different areas of lumbar belt (left side, front and back) and comparison of different lumbar belts. Results will be used in a finite elements model to determine lumbar belt impact in intern body. In long term, this kind of study will be done on human.

  13. Discussion about the relationship between seismic belt and seismic statistical zone

    Institute of Scientific and Technical Information of China (English)

    潘华; 金严; 胡聿贤

    2003-01-01

    This paper makes a summary of status of delimitation of seismic zones and belts of China firstly in aspects of studying history, purpose, usage, delimiting principles, various presenting forms and main specialties. Then the viewpoints are emphasized, making geographical divisions by seismicity is just the most important purpose of delimiting seismic belts and the concept of seismic belt is also quite different from that of seismic statistical zone used in CPSHA method. The concept of seismic statistical zone and its history of evolvement are introduced too. Large differences between these two concepts exist separately in their statistical property, actual meaning, gradation, required scale, and property of refusing to overlap each other, aim and usage of delimitation. But in current engineering practice, these two concepts are confused. On the one hand, it causes no fit theory for delimiting seismic statistical zone in PSHA to be set up; on the other hand, researches about delimitation of seismic belts with purposes of seismicity zoning and studying on structural environment, mechanism of earthquake generating also pause to go ahead. Major conclusions are given in the end of this paper, that seismic statistical zone bases on the result of seismic belt delimiting, it only arises in and can be used in the especial PSHA method of China with considering spatially and temporally inhomogeneous seismic activities, and its concept should be clearly differentiated from the concept of seismic belt.

  14. Seismic tomography beneath the orogenic belts and adjacent basins of northwestern China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave recorded in seismic networks in Xinjiang, Qinghai, Gansu of China and Kyrgyzstan. The velocity images of upper crust demonstrate the tectonic framework on the ground surface. High velocities are observed beneath orogenic belts, and low velocities are observed in the basins and depressions that are obviously related to unconsolidated sediments. The velocity image in mid-crust maintains the above features, and in addition low velocities appear in some earthquake regions and a low velocity boundary separates the western Tianshan Mts. from eastern Tianshan Mts. The orogenic belts and the northern Tibetan plateau have a Moho depth over 50 km, whereas the depths of the Moho in basins and depressions are smaller than 50 km. The velocity images of upper mantle clearly reveal the colliding relationship and location of deep boundaries of the continental blocks in northwestern China, indicating a weakness of the upper mantle structure of orogenic belts. The top depth of upper mantle asthenosphere varies from place to place. It seems shallower under the northern Tibetan plateau, Altay and Qilian Mts., and deeper under the Tarim and Tianshan regions. Hot mantle probably rose to the bottom of some orogenic belts along tectonic boundaries when continental blocks collided to each other. Therefore their dynamic features are closely correlated to the formation and evolution of orogenic belts in northwestern China.

  15. Development of Computational Models for Coiling Process with the Belt Wrapper

    Science.gov (United States)

    Park, Yonghui; Park, Hyunchul

    2016-10-01

    This study introduces coiling mechanism with the belt wrapper to understand a force equilibrium for successful coiling. By establishing a finite element (FE) model, strips were coiled 2 to 3 rotations by the belt wrapper on the sleeve without coiling tension T, then T was applied to the opposite side of the strips near the pinch roller, and the belt wrapper was removed from the strip coil at the same time. Additionally, analytical model corresponding to FE model was defined by thick and thin cylinder theorems to quantize coiling mechanisms. Especially elasticity of the belt wrapper E [N/m2], coiling tension T [N/m2], and friction coefficient μ were checked on how these variables affect each other, were converted into pressure P [N/m2], and P were used to calculate when the strip coil come untied. For instance, the strip coil came untied when E was lower than 1 × 109 N/m2 corresponding to ( {{{{Pressure}} {{on}} {{outmost}} {{of the belt wrapper}} P_{{o,belt}} }/{{{Pressure} {{on}} {{innermost}} {{of the sleeve}} P_{{i,sleeve}} }} = 0.877} ) . Lastly, radial stress on the outmost of the sleeve σ r,o,sleeve [N/m2] according to E were compared to the previous coiling method with the grooved joint to see how these methods are different. Based on these results, this paper suggests coiling criteria to avoid coiling failure of slip of the strip coil.

  16. The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt

    CERN Document Server

    Hsieh, Henry H

    2009-01-01

    The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: (1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit, or (2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If (1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if (2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. I conducted just such a survey -- the Hawaii Trails Project -- of selected main-belt asteroids in a search for objec...

  17. Classification of the rift zones of venus: Rift valleys and graben belts

    Science.gov (United States)

    Guseva, E. N.

    2016-05-01

    The spatial distribution of rift zones of Venus, their topographic configuration, morphometric parameters, and the type of volcanism associating with rifts were analyzed. This allowed the main characteristic features of rifts to be revealed and two different types of rift-forming structures, serving for classification of rift zones as rift valleys and graben belts, to be isolated. These structural types (facies) of rift zones are differently expressed in the relief: rift valleys are individual deep (several kilometers) W-shaped canyons, while graben belts are clusters of multiple V-shaped and rather shallow (hundreds of meters) depressions. Graben belts are longer and wider, as compared to rift valleys. Rift valleys are spatially associated with dome-shaped volcanic rises and large volcanos (concentrated volcanic sources), while graben belts do not exhibit such associations. Volcanic activity in the graben belts are presented by spacious lava fields with no apparent sources of volcanism. Graben belts and rift valleys were formed during the Atlian Period of geologic history of Venus, and they characterized the tectonic style of the planet at the late stages of its geologic evolution. Formation of this or that structural facies of the rift zones of Venus were probably governed by the thickness of the lithosphere, its rheological properties, and the development degree of the mantle diapirs associating with rift zones.

  18. Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

    Science.gov (United States)

    Savage, James C.; Simpson, Robert W.

    2013-01-01

    The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

  19. ORBITS, MASSES, AND EVOLUTION OF MAIN BELT TRIPLE (87) SYLVIA

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Julia; Margot, Jean-Luc [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Rojo, Patricio [Departamento de Astronomia, Universidad de Chile, Santiago (Chile)

    2012-08-15

    Sylvia is a triple asteroid system located in the main belt. We report new adaptive optics observations of this system that extend the baseline of existing astrometric observations to a decade. We present the first fully dynamical three-body model for this system by fitting to all available astrometric measurements. This model simultaneously fits for individual masses, orbits, and primary oblateness. We find that Sylvia is composed of a dominant central mass surrounded by two satellites orbiting at 706.5 {+-} 2.5 km and 1357 {+-} 4.0 km, i.e., about 5 and nearly 10 primary radii. We derive individual masses of 1.484{sup +0.016}{sub -0.014} Multiplication-Sign 10{sup 19} kg for the primary (corresponding to a density of 1.29 {+-} 0.39 g cm{sup -3}), 7.33{sup +4.7}{sub -2.3} Multiplication-Sign 10{sup 14} kg for the inner satellite, and 9.32{sup +20.7}{sub -8.3} Multiplication-Sign 10{sup 14} kg for the outer satellite. The oblateness of the primary induces substantial precession and the J{sub 2} value can be constrained to the range of 0.0985-0.1. The orbits of the satellites are relatively circular with eccentricities less than 0.04. The spin axis of the primary body and the orbital poles of both satellites are all aligned within about 2 deg of each other, indicating a nearly coplanar configuration and suggestive of satellite formation in or near the equatorial plane of the primary. We also investigate the past orbital evolution of the system by simulating the effects of a recent passage through 3:1 mean-motion eccentricity-type resonances. In some scenarios this allow us to place constraints on interior structure and past eccentricities.

  20. Interpreting the densities of the Kuiper belt's dwarf planets

    Science.gov (United States)

    Barr, Amy C.; Schwamb, Megan E.

    2016-08-01

    Kuiper belt objects (KBOs) with absolute magnitude less than 3 (radius ≳500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g cm-3. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent of the total colliding mass, is lost. The fragments would not remain in physical or dynamical proximity to the parent body. The ice loss process has not yet been demonstrated numerically, which could be due to the paucity of KBO origin simulations, or missing physical processes in the impact models. If our hypothesis is correct, we predict that large KBOs with small moons should be denser than the primordial material, and that the mean density of Orcus should be close to the primordial value.

  1. Triggering Comet-Like Activity of Main Belt Comets

    Science.gov (United States)

    Haghighipour, N.; Maindl, T. I.; Schäfer, C.; Speith, R.; Dvorak, R.

    2016-01-01

    Main Belt Comets (MBCs) have attracted a great deal of interest since their identification as a new class of bodies by Hsieh and Jewitt in 2006. Much of this interest is due to the implication that MBC activity is driven by the sublimation of volatile material (presumed to be water-ice) presenting these bodies as probable candidates for the delivery of a significant fraction of Earth's water. Results of the studies of the dynamics of MBCs suggest that these objects might have formed in-situ as the remnants of the break-up of large icy asteroids. Simulations also show that collisions among MBCs and small objects could have played an important role in triggering the cometary activity of these bodies. Such collisions might have exposed sub-surface water-ice which sublimated and created thin atmospheres and tails around MBCs. In order to drive the effort of understanding the nature of the activation of MBCs, we have investigated these collision processes by simulating the impacts in detail using a smooth particle hydrodynamics (SPH) approach that includes material strength and fracture models. We have carried out simulations for a range of impact velocities and angles, allowing m-sized impactors to erode enough of an MBC's surface to expose volatiles and trigger its activation. Impact velocities were varied between 0.5 km/s and 5.3 km/s, and the projectile radius was chosen to be 1 m. As expected, we observe significantly different crater depths depending on the impact energy, impact angle, and MBC's material strength. Results show that for all values of impact velocity and angle, crater depths are only a few meters, implying that if the activity of MBCs is due to the sublimation of water-ice, ice has to exist in no deeper than a few meters from the surface. We present details of our simulations and discuss the implications of their results.

  2. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    Energy Technology Data Exchange (ETDEWEB)

    Marrs, R

    2002-11-13

    In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many more satellites in orbit, and it is important to understand their vulnerability to radiation belt pumping from nuclear explosions at high altitude or in space. This report presents the results of a calculation of the contribution of neutron beta decay to artificial belt pumping. For most high altitude nuclear explosions, neutrons are expected to make a smaller contribution than fission products to the total trapped electron inventory, and their contribution is usually neglected. However, the neutron contribution may dominate in cases where the fission product contribution is suppressed due to the altitude or geomagnetic latitude of the nuclear explosion, and for regions of the radiation belts with field lines far from the detonation point. In any case, an accurate model of belt pumping from high altitude nuclear explosions, and a self-consistent explanation of the 1962 data, require inclusion of the neutron contribution. One recent analysis of satellite measurements of electron flux from the 1962 tests found that a better fit to the data is obtained if the neutron contribution to the trapped electron inventory was larger than that of the fission products [l]. Belt pumping from high altitude nuclear explosions is a complicated process. Fission fragments are dispersed as part of the ionized bomb debris, which is constrained and guided by the earth's magnetic field. Those fission products that beta decay before being lost to the earth's atmosphere can contribute trapped energetic electrons to the earth's radiation belts. There has been a large effort to develop computer models for

  3. Motion Track Modeling and Analysis of Belt Spindle under Combined Effects of Bending Moment-Torque-Thermal Deformation

    Institute of Scientific and Technical Information of China (English)

    齐向阳; 高卫国; 刘腾; 张大卫

    2015-01-01

    The motion track of belt spindle is important for the radial error of belt spindle. An analytical modeling method for the motion track of belt spindle under the combined effects of bending moment-torque-thermal deforma-tion is proposed in this paper. Three running phases of belt spindle have been analyzed and modeled:the start-up phase with leaping change due to the change in force and bending moment, the accelerating phase with axis deflection, and the constant speed phase with axis regression because of the combined effects of bending moment-torque-thermal de-formation. The simulation and test were completed on the belt spindle of SKVM850 machine tool, which illustrates the variation law of the radial error of belt spindle during the whole running phases.

  4. What effect do substorms have on the content of the radiation belts?

    Science.gov (United States)

    Rae, I. J.; Murphy, K. R.; Freeman, M. P.; Huang, C.‐L.; Spence, H. E.; Boyd, A. J.; Coxon, J. C.; Jackman, C. M.; Kalmoni, N. M. E.; Watt, C. E. J.

    2016-01-01

    Abstract Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV “seed” population into the inner magnetosphere which is subsequently energized through wave‐particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to 3 times as many increases in TRBEC following substorm intervals. There is a lag of 1–3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM‐H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.

  5. Innermost Van Allen Radiation Belt for High Energy Protons at Saturn

    Science.gov (United States)

    Cooper, John F.

    2008-01-01

    The high energy proton radiation belts of Saturn are energetically dominated by the source from cosmic ray albedo neutron decay (CRAND), trapping of protons from beta decay of neutrons emitted from galactic cosmic ray nuclear interactions with the main rings. These belts were originally discovered in wide gaps between the A-ring, Janus/Epimetheus, Mimas, and Enceladus. The narrow F and G rings significant affected the CRAND protons but did not produce total depletion. Voyager 2 measurements subsequently revealed an outermost CRAND proton belt beyond Enceladus. Although the source rate is small, the trapping times limited by radial magnetospheric diffusion are very long, about ten years at peak measured flux inwards of the G ring, so large fluxes can accumulate unless otherwise limited in the trapping region by neutral gas, dust, and ring body interactions. One proposed final extension of the Cassini Orbiter mission would place perikrone in a 3000-km gap between the inner D ring and the upper atmosphere of Saturn. Experience with CRAND in the Earth's inner Van Allen proton belt suggests that a similar innermost belt might be found in this comparably wide region at Saturn. Radial dependence of magnetospheric diffusion, proximity to the ring neutron source, and northward magnetic offset of Saturn's magnetic equator from the ring plane could potentially produce peak fluxes several orders of magnitude higher than previously measured outside the main rings. Even brief passes through such an intense environment of highly penetrating protons would be a significant concern for spacecraft operations and science observations. Actual fluxes are limited by losses in Saturn's exospheric gas and in a dust environment likely comparable to that of the known CRAND proton belts. The first numerical model of this unexplored radiation belt is presented to determine limits on peak magnitude and radial profile of the proton flux distribution.

  6. What controls the growth and shape of the Himalayan foreland fold-and-thrust belt?

    Science.gov (United States)

    Grujic, Djordje; Hirschmiller, John; Mallyon, Deirdre

    2014-05-01

    We provide empirical evidence for the impact of surface processes on the structure and geometry of the present-day foreland fold-and-thrust belt (FTB) of the Himalaya. We have reconstructed and analysed ten balanced cross sections distributed along the entire length of the Himalayan arc. Here, we focus on the Siwalik Group, which represents the deformed part of the foreland basin and consists of synorogenic middle Miocene to Pleistocene sediments that form the youngest and frontal part of the Himalayan orogen. Within the active foreland fold-and-thrust belt of the Himalaya, extension, strain rate, and belt morphology vary systematically from west to east. Strain rates correlate well with west-to east increases in convergence rates according to both long-term plate velocity data and GPS data, suggesting that Pliocene to Holocene shortening is externally imposed and related to plate convergence rates. Conversely, the eastward decrease in belt width corresponds to an eastward increase in rainfall rates and specific stream power. Although mass accretion rates have not been well constrained, we argue that they remain relatively constant along the FTB. We suggest that the morphology of the Himalayan FTB is controlled primarily by erosion, in accordance with the critical taper model. Surface material removal is mainly controlled through rainfall and runoff and can be expressed as specific stream power. Thus, we propose that climatically induced erosion is the principal control on Himalayan foreland fold-and-thrust belt morphology. We test this hypothesis through a series of 1D numerical models. Among the parameters controlling the form of a wedge, lithology, erodibility, and rock mechanical properties are relatively homogeneous throughout the belt. Hence, within the range of observed values in the Himalaya, we investigate the sensitivity of the shape of the Himalayan fold-and-thrust belt to the sole-out depth of the basal décollement, flux of tectonically added material

  7. Canonical Correlation Factors Causing the Formation of Accumulated Sand-belts along the Oasis Fringe in Hexi Corridor

    Institute of Scientific and Technical Information of China (English)

    Chang; Zhaofeng; Wang; Qiangqiang; Zhang; Jianhui; Tang; Jinnian; Zhu; Shujuan; Fan; Baoli; Zhang; Dabiao; Liu; Shizeng; Zhang; Guozhong; Li; Aide

    2014-01-01

    Accumulated sand-belts refer to those formed along the oasis fringe,especially at the upwind location,due to the accumulation of sand blocked by farmland windbreak. In the 60 years since the foundation of new China,a lot of trees have been planted for desertification combating in northwest and north China,thus,accumulated sand-belts were formed at the upwind location. The formation and the ecological effects of the accumulated sand-belts along the oasis fringe is a new scientific concern. To study the formation causes of these belts in Hexi corridor,21 samples were selected,and the height / width of the belts,as well as the vegetation,soil,soil moisture and climatic factors were investigated. This paper analyzed the correlation between the height / width of the belts and the vegetation,soil,soil moisture and climatic factors using the methods of variance analysis,correlation analysis and canonical correlation analysis. The results indicate that: the accumulated sand-belts take a trend of being high and wide in the east whereas low and narrow in the west,and most of the parts tend to be stable; the species on the belts are dominated by Tamarix austromongolica,the vegetation cover and the pure vegetation cover of different dominant species on the leeward slope of the accumulated sand-belts vary significantly. The canonical correlation analysis shows that: the height and width of accumulated sand-belt is the interaction of precipitation,distance to the sand source,leeward vegetation cover and annual average wind speed. Moreover,the height of accumulated sand-belts are negatively correlated to the soil moisture at the depth of 30- 50 cm,air humidity and leeward vegetation cover,and the width of the belts is also negatively correlated with the distance to the sand source. The ecological effects of the accumulated sand-belts are both positive( stopping sands from moving into farmland,protective role as an obstacle)and negative( when the belts decay and activate one day

  8. The Pattern and Evolution of the Permian Palaeobiogeography and Tectonic Palaeogeography in Jilin and Heilongjiang Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    Peng Xiangdong; Li Xiaomin; Liu Pengju

    2000-01-01

    The orogenic belt locates between the North China plate and Siberia plate. The Permian palaeobiogeography and tectonic palaeogeography changed quickly and clearly. The line from Changchun to Yanji is an important palaeobiogeographic provincing line, which may be the collission suture belt of the North China plate and north middle massifs. The orogenic belt has been divided into 2 regions: the North middle massif region and the North Margin of North China plate, the pattern and evolution of Permian palaeobiogeography in the present area were discussed and the Permian biota mixture and its significants were analysed. Then, Based on the above, the Permian tectonic palaeogeography of the orogenic belt is reconstructed.

  9. Potential Jupiter-Family comet contamination of the main asteroid belt

    Science.gov (United States)

    Hsieh, Henry H.; Haghighipour, Nader

    2016-10-01

    We present the results of "snapshot" numerical integrations of test particles representing comet-like and asteroid-like objects in the inner Solar System aimed at investigating the short-term dynamical evolution of objects close to the dynamical boundary between asteroids and comets as defined by the Tisserand parameter with respect to Jupiter, TJ (i.e., TJ = 3). As expected, we find that TJ for individual test particles is not always a reliable indicator of initial orbit types. Furthermore, we find that a few percent of test particles with comet-like starting elements (i.e., similar to those of Jupiter-family comets) reach main-belt-like orbits (at least temporarily) during our 2 Myr integrations, even without the inclusion of non-gravitational forces, apparently via a combination of gravitational interactions with the terrestrial planets and temporary trapping by mean-motion resonances with Jupiter. We estimate that the fraction of real Jupiter-family comets occasionally reaching main-belt-like orbits on Myr timescales could be on the order of ∼ 0.1-1%, although the fraction that remain on such orbits for appreciable lengths of time is certainly far lower. For this reason, the number of JFC-like interlopers in the main-belt population at any given time is likely to be small, but still non-zero, a finding with significant implications for efforts to use apparently icy yet dynamically asteroidal main-belt comets as tracers of the primordial distribution of volatile material in the inner Solar System. The test particles with comet-like starting orbital elements that transition onto main-belt-like orbits in our integrations appear to be largely prevented from reaching low eccentricity, low inclination orbits, suggesting that the real-world population of main-belt objects with both low eccentricities and inclinations may be largely free of this potential occasional Jupiter-family comet contamination. We therefore find that low-eccentricity, low-inclination main-belt

  10. Formation cause of thermal infrared high temperature belt along Honghe fault and its relation to earthquakes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Aiming at two Dayao earthquakes with magnitude more than 6 occurred in 2003 in Yunnan Province, we analyzed and interpreted the NOAA satellite thermal infrared images of 1999, 2003 and 2004 in Chuandian region, and also calculated the annual variation of brightness temperature of the hot belt along Honghe fault to explore the formation cause of the high temperature belt and its relation to the earthquakes. The results show that the high temperature belt along Honghe fault is caused by geographic environment factors, such as water system and terrain. But the annual average brightness temperature of the belt in earthquake year of 2003 is clearly higher than that in no earthquake years of 1999 and 2004, this maybe indicates that the thermal activities of Honghe fault increase in earthquake years, and can cause the annual variation anomaly of brightness temperature. We can detect and monitor this thermal activities of Honghe fault before earthquake by analyzing and comparing the relative changes of thermal infrared brightness temperature of the hot belt in different years

  11. Research on Magnetic Model of Low Resistance Permanent Magnet Pipe Belt Conveyor

    Science.gov (United States)

    Wang, Shuang; Li, De-yong; Guo, Yong-cun

    2016-09-01

    In view of the feasibility of a new type of low resistance permanent magnet pipe belt conveyor, the magnetic properties of the permanent magnet magnetic pipe conveyor belt system are studied. Based on the molecular current hypothesis, the mathematical model of the three dimensional radial magnetic force of permanent magnet pipe conveyor belt was established. The mathematical model of the radial magnetic force was derived, and the influence factors of the radial magnetic force were derived. The finite element simulation of permanent magnet-magnetic pipe conveyor belt magnetic model was carried out, then the magnetic flux density distribution chart under the conditions of different remanence intensity of different permanent magnet and different lengths of the permanent magnets (along the transport direction) were obtained. The simulation results are consistent with the calculation results, which shows that the permanent magnet pipe belt conveyor is feasible. Under certain conditions, the radial magnetic force has nonlinear increase relations with residual magnetism of permanent magnet and the length of the permanent magnet (along the transport direction).

  12. The Asteroid Belt as a Relic From a Chaotic Early Solar System

    CERN Document Server

    Izidoro, Andre; Pierens, Arnaud; Morbidelli, Alessandro; Winter, Othon C; Nesvorny, David

    2016-01-01

    The orbital structure of the asteroid belt holds a record of the Solar System's dynamical history. The current belt only contains ${\\rm \\sim 10^{-3}}$ Earth masses yet the asteroids' orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter's orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth's orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may have been excited to their current state if Jupiter and Saturn's early orbits were chaotic. Stochastic variations in the gas giants' orbits cause resonances to continually jump across the main belt and excite the asteroids' orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at...

  13. Dynamical evolution of V-type asteroids in the central main belt

    CERN Document Server

    Carruba, V; Domingos, R C; Santos, C R Dos; Souami, D

    2014-01-01

    V-type asteroids are associated with basaltic composition, and are supposed to be fragments of crust of differentiated objects. Most V-type asteroids in the main belt are found in the inner main belt, and are either current members of the Vesta dynamical family (Vestoids), or past members that drifted away. However, several V-type photometric candidates have been recently identified in the central and outer main belt. The origin of this large population of V-type objects is not well understood. Since it seems unlikely that Vestoids crossing the 3J:-1A mean-motion resonance with Jupiter could account for the whole population of V-type asteroids in the central and outer main belt, origin from local sources, such as the parent bodies of the Eunomia, and of the Merxia and Agnia asteroid families, has been proposed as an alternative mechanism. In this work we investigated the dynamical evolution of the V-type photometric candidates in the central main belt, under the effect of gravitational and non-gravitational f...

  14. Structural Geochemical Study of the Yuxi Fold-Thrust Belt in the Southern North China Plate

    Institute of Scientific and Technical Information of China (English)

    Li Wenyong; Xia Bin; Li Dongxu

    2006-01-01

    The Yuxi (豫西) fold-thrust fracture belt is part of the gigantic fold-thrust fracture belt that extends NW in the southern North China plate. The contents of major elements of tectonites were analyzed by ICP-AES. The analysis of chemical compositions and new stress minerals indicates: extending from the surrounding country rocks to the center of the fracture belt, the Fe2 O3 content gradually increases while the FeO content gradually decreases; regular increase, decrease or peak changes are shown for chemical compositions likeSiO2, Al2O3, Fe2O3, MgO, CaO, FeO, loss on ignition, TiO2,K2O, Na2O, etc.. New stress minerals are developed for the south branch and few for the north branch.The characteristics of chemical compositions and new stress minerals of the thrust fracture demonstrate that the fracture belt has undergone a process from a closed reducing environmental system to a relatively open, oxidizing environmental system, and compressive fractures have resulted from compression in the late stages of evolution, and the dynamothermal metamorphism and thrusting intensities are different between the south and north branches of the belt, which is strong for the south branch but relatively weak for the north branch.

  15. CubeSat-Associated Radiation Belt Research: Recent and Upcoming Observations

    Science.gov (United States)

    Blum, Lauren; Li, Xinlin; Schiller, Quintin

    2016-07-01

    Interest in CubeSats has grown dramatically in the past decade within the space physics community. While CubeSats are generally accepted now to be useful tools for education and technology development/demonstration, their ability to provide scientific value is often still questioned. Radiation belt physics, however, is one area in which the scientific utility of these small platforms has been demonstrated and continues to offer great promise. The Colorado Student Space Weather Experiment (CSSWE) CubeSat, designed, built, tested, and operated by students at University of Colorado with mentoring from LASP professionals, was one of the first of now a long line of CubeSats designed to study radiation belt dynamics. Launched in September 2012, just a few weeks after NASA's Van Allen Probes, CSSWE provided valuable measurements of energetic electrons and protons from low-Earth orbit for two years, well beyond its nominal 3-month mission lifetime. The status of and results from CSSWE will be presented, with an emphasis on how these measurements have been combined with those from balloons and larger satellite missions to better understand radiation belt electron acceleration and loss processes. Some highlights from other radiation belt-related CubeSats will also be presented, along with upcoming missions. Radiation belt studies are a prime example of how small inexpensive CubeSats can be used to provide valuable scientific measurements and complement larger missions.

  16. The impact of radiation belts region on top side ionosphere condition during last solar minimum.

    Science.gov (United States)

    Rothkaehl, Hanna; Przepiórka, Dororta; Matyjasiak, Barbara

    2014-05-01

    The wave particle interactions in radiation belts region are one of the key parameters in understanding the global physical processes which govern the near Earth environment. The populations of outer radiation belts electrons increasing in response to changes in the solar wind and the interplanetary magnetic field, and decreasing as a result of scattering into the loss cone and subsequent absorption by the atmosphere. The most important question in relation to understanding the physical processes in radiation belts region relates to estimate the ratio between acceleration and loss processes. This can be also very useful for construct adequate models adopted in Space Weather program. Moreover the wave particle interaction in inner radiation zone and in outer radiation zone have significant influence on the space plasma property at ionospheric altitude. The aim of this presentation is to show the manifestation of radiation belts region at the top side ionosphere during the last long solar minimum. The presentation of longitude and seasonal changes of plasma parameters affected by process occurred in radiation belts region has been performed on the base of the DEMETER and COSMIC 3 satellite registration. This research is partly supported by grant O N517 418440

  17. Junction and Evolution of the Qinling, Qilian and Kunlun Orogenic Belts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As the main part of the "central mountain system" in the continent of China, the Qinling, Qilian and Kunlun orogenic belts have been comprehensively and deeply studied since the 1970s and rich fruits have been reaped. However, these achievements were mostly confined to an individual orogenic belt and the study of the mutual relationship among the three orogenic belts was obliged to depend on comparative studies. Different views were produced therefrom. The material composition and structural features of the junction region show that there are several epicontinental and intracontinental transform faults developed in different periods. Restricted by these transform faults, the large-scale lateral movements and, as a consequence, complicated magmatism and tectonic deformation took place in the orogenic belts. According to these features, the authors put forward a three-stage junction and evolution model and point out that there is not a single junction zone traversing from west to east but that the three orogenic belts have been joined progressively by the epicontinental and intracontinental transform faults.

  18. STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the Orbit of Fomalhaut b

    CERN Document Server

    Kalas, Paul; Fitzgerald, Michael P; Clampin, Mark

    2013-01-01

    We present new optical coronagraphic data of the bright star Fomalhaut obtained with the HST in 2010/2012 using STIS. Fomalhaut b is recovered at both epochs to high significance. The observations include the discoveries of tenuous nebulosity beyond the main dust belt detected to at least 209 AU projected radius and a ~50 AU wide azimuthal gap in the belt northward of Fom b. The morphology of Fomalhaut b appears elliptical in the STIS detections. We show that residual noise in the processed data can plausibly result in point sources appearing extended. A MCMC analysis demonstrates that the orbit of Fom b is highly eccentric, with e=0.8+/-0.1, a=177+/-68 AU, and q = 32+/-24 AU. Fom b is apsidally aligned with the belt and 90% of allowed orbits have mutual inclination 36 deg or less. Fomalhaut b's orbit is belt-crossing in projection, but only 12% of possible orbits have nodes within a 25 AU wide belt annulus (133-158 AU). The high e invokes a dynamical history where Fom b may have experienced a significant dyn...

  19. TSUBASA (MDS-1) observations of energetic electrons and magnetic field variations in outer radiation belt

    Science.gov (United States)

    Nakamura, M.; Matsuoka, H.; Liu, H.; Koshiishi, H.; Koga, K.; Matsumoto, H.; Goka, T.

    2002-12-01

    We have investigated variations of energetic electrons (> 0.4 MeV) and magnetic field in the radiation belt obtained from the Standard DOse Monitor (SDOM) and the MAgnetoMeter (MAM) of the Space Environment Data Acquisition equipment (SEDA) onboard TSUBASA (the Mission Demonstration Test Satellite (MDS)-1) launched on February 4, 2002. Since TSUBASA is operated in the geostationary transfer orbit, it has provided rare opportunities of directly observing near-equatorial radiation belt plasma particles and magnetic field, having already included several large magnetic storms. The energetic electrons in the outer radiation belt are contributors to the total radiation dose deposited in lightly shielded spacecraft electronics for high altitude orbits and are known to have a drastic variability associated with geomagnetic storm and high speed solar wind streams. The abrupt energetic electron flux decreases in the outside of outer radiation belt show characteristic variations of in situ magnetic field. These observations have implications for the possible mechanisms of the depletion and the following recovery and/or buildup of energetic electrons in the outer radiation belt.

  20. A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.

    Directory of Open Access Journals (Sweden)

    Olivier Manigart

    Full Text Available The pattern of epidemic meningococcal disease in the African meningitis belt may be influenced by the background level of population immunity but this has been measured infrequently. A standardised enzyme-linked immunosorbent assay (ELISA for measuring meningococcal serogroup A IgG antibodies was established at five centres within the meningitis belt. Antibody concentrations were then measured in 3930 individuals stratified by age and residence from six countries. Seroprevalence by age was used in a catalytic model to determine the force of infection. Meningococcal serogroup A IgG antibody concentrations were high in each country but showed heterogeneity across the meningitis belt. The geometric mean concentration (GMC was highest in Ghana (9.09 μg/mL [95% CI 8.29, 9.97] and lowest in Ethiopia (1.43 μg/mL [95% CI 1.31, 1.57] on the margins of the belt. The force of infection was lowest in Ethiopia (λ = 0.028. Variables associated with a concentration above the putative protective level of 2 μg/mL were age, urban residence and a history of recent vaccination with a meningococcal vaccine. Prior to vaccination with the serogroup A meningococcal conjugate vaccine, meningococcal serogroup A IgG antibody concentrations were high across the African meningitis belt and yet the region remained susceptible to epidemics.

  1. Heliocentric zoning of the asteroid belt by aluminum-26 heating

    Science.gov (United States)

    Grimm, R. E.; Mcsween, H. Y., Jr.

    1993-01-01

    depends only on the initial orbit properties and distribution of the planesimal swarm. In order to demonstrate the basic dependence of thermal evolution on semimajor axis, we parameterized accretion time across the asteroid belt according to tau varies as a(sup n) and calculated the subsequent thermal history. Objects at a specified semimajor axis were assumed to have the same accretion time, regardless of size. We set the initial Al-26/Al-27 ratio = 6 x 10(exp -5) and treated n and tau(sub 0) at a(sub 0) = 3 AU as adjustable parameters. The thermal model included temperature-dependent properties of ice and rock (CM chondrite analog) and the thermodynamic effects of phase transitions.

  2. Lithospheric seismic fabrics of Sulu ultrahigh-pressure metamorphic belt

    Institute of Scientific and Technical Information of China (English)

    YANG; Wencai; YANG; Wuyang; JIN; Zhenmin; CHENG; Zhenyan

    2005-01-01

    Calibration of seismic reflectors appearing in the crust of the Chinese continent scientific drilling site can be completed through the correlation studies between direct evidences, such as the drill cores, and geophysical signatures; therefore the interpretation of geophysical data could produce reliable results of crustal structure and composition. On the other hand, there are two Cenozoic volcanoes close to the scientific drilling site; analyzing composition of xenoliths existent in the volcanoes and evaluating their seismic velocities can also offer information about the mantle and lower crust. After the calibration via cores and well-logging data, the seismic reflectors appearing in the UHP belt can be caused by lithological changes within the UHP rock slice, ductile shearing rock-suites, and later fracture zones. Among these sources, ductile shearing resulted in displacement and detachment of original rock-sheets, producing some rock-interbeds of several hundred meters thick that are named the ductile shearing rock-suites. A suite consists of mylonized gneiss and eclogite slices that underwent shearing, becoming the major mechanism responsible to generate regional strong reflections. The UHP rock-slice is characterized by complicated structures and high density, high seismic velocity and high electrical resistivity, its thickness is usually less than 11 km. Velocity and density of the gneiss-layer beneath gradually tend to normal with increasing depth. Based on the xenoliths we can infer that the middle crust contains a lot of gneisses, and the lower crust consists of different granulites. The lithospheric mantle has multi-layer structures and consists mainly of spinal lherzolite and harzburgite, implying late Mesozoic lithospheric thinning. The seismic fabrics with different origins were possible products of different geodynamic processes. For instance, the UHP rock-slice was produced by the UHP metamorphic process and the exhumation of subducted

  3. Geoinformatics and Data Fusion in the Southwestern Utah Mineral Belt

    Science.gov (United States)

    Kiesel, T.; Enright, R.

    2012-12-01

    Data Fusion is a technique in remote sensing that combines separate geophysical data sets from different platforms to yield the maximum information of each set. Data fusion was employed on multiple sources of data for the purposes of investigating an area of the Utah Mineral Belt known as the San Francisco Mining District. In the past many mineral deposits were expressed in or on the immediate surface and therefore relatively easy to locate. More modern methods of investigation look for evidence beyond the visible spectrum to find patterns that predict the presence of deeply buried mineral deposits. The methods used in this study employed measurements of reflectivity or emissivity features in the infrared portion of the electromagnetic spectrum for different materials, elevation data collected from the Shuttle Radar Topography Mission and indirect measurement of the magnetic or mass properties of deposits. The measurements were collected by various spaceborne remote sensing instruments like Landsat TM, ASTER and Hyperion and ground-based statewide geophysical surveys. ASTER's shortwave infrared bands, that have been calibrated to surface reflectance using the atmospheric correction tool FLAASH, can be used to identify products of hydrothermal alteration like kaolinite, alunite, limonite and pyrophyllite using image spectroscopy. The thermal infrared bands once calibrated to emissivity can be used to differentiate between felsic, mafic and carbonate rock units for the purposes of lithologic mapping. To validate results from the extracted spectral profiles existing geological reports were used for ground truth data. Measurements of electromagnetic spectra can only reveal the composition of surface features. Gravimetric and magnetic information were utilized to reveal subsurface features. Using Bouguer anomaly data provided by the USGS an interpreted geological cross section can be created that indicates the shape of local igneous intrusions and the depth of

  4. EFFECTS OF BELT SPEED, PRESSURE AND GRIT SIZE ON THE SANDING OF Pinus elliottii WOOD

    Directory of Open Access Journals (Sweden)

    Manoel Cléber de Sampaio Alves

    2015-03-01

    Full Text Available The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size on the output parameters (temperature and surface roughness for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD. The results were analyzed employing the analysis of variance (ANOVA with 5% of significance level. Only grit sizes were significant to different temperature levels. The same outcome was observed for roughness, where only grits sizes were significant. No interaction between the pressure and belt speed factors were observed for all the results analyzed.

  5. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction

    Directory of Open Access Journals (Sweden)

    Rebecca Gyawu

    2015-01-01

    Full Text Available In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%, restaurants (19.7%, fast food restaurants (16.4%, small supermarkets (8.2%, and large supermarket and farmers' markets (3.3 %, respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p < 0.0001 higher health scores than the other store types. A few health promotion messages were highly visible or obscurely positioned in some RFOs. The Alabama Black Belt food environment had limited opportunities for healthy food choices.

  6. Atmospheres and surfaces of small bodies and dwarf planets in the Kuiper Belt

    Directory of Open Access Journals (Sweden)

    Schaller E.L.

    2010-12-01

    Full Text Available Kuiper Belt Objects (KBOs are icy relics orbiting the sun beyond Neptune left over from the planetary accretion disk. These bodies act as unique tracers of the chemical, thermal, and dynamical history of our solar system. Over 1000 Kuiper Belt Objects (KBOs and centaurs (objects with perihelia between the giant planets have been discovered over the past two decades. While the vast majority of these objects are small ( 6-meter telescopes, have allowed for the first detailed studies of their surfaces and atmospheres. Visible and near-infrared spectroscopy of KBOs and centaurs has revealed a great diversity of surface compositions. Only the largest and coldest objects are capable of retaining volatile ices and atmospheres. Knowledge of the dynamics, physical properties, and collisional history of objects in the Kuiper belt is important for understanding solar system formation and evolution.

  7. SOME FUNDAMENTAL PROBLEMS OF TECTONICS AND GEODYNAMICS OF THE CENTRAL ASIAN FOLDED BELT

    Directory of Open Access Journals (Sweden)

    I. V. Gordienko

    2015-09-01

    Full Text Available This study addresses some fundamental problems of tectonics and geodynamics of the Central Asian folded belt, the largest tectonic structure in Eurasia. The article presents results of long-term researches conducted by scientists and geologists specialized in various disciplines which contribute to the knowledge of the origin and breakup of Rodinia and formation of the Paleo-Asian Ocean. It considers problems of development of the Central Asian folded belt that was formed in the area of the Paleo-Asian Ocean and describes its subduction magmatism and marginal-marine sedimentation, formation of island arcs, processes of exhumation of the oceanic crust and formation of high-pressure blueschist and eclogite-blueschist complexes. Outstanding fundamental issues of the geodynamic evolution of the Central Asian folded belt are noted. 

  8. Properties of Hermean plasma belt: Numerical simulations and comparison with MESSENGER data

    Science.gov (United States)

    Herčík, David; Trávníček, Pavel M.; Å tverák, Å. těpán.; Hellinger, Petr

    2016-01-01

    Using a global hybrid model and test particle simulations we present a detailed analysis of the Hermean plasma belt structure. We investigate characteristic properties of quasi-trapped particle population characteristics and its behavior under different orientations of the interplanetary magnetic field. The plasma belt region is constantly supplied with solar wind protons via magnetospheric flanks and tail current sheet region. Protons inside the plasma belt region are quasi-trapped in the magnetic field of Mercury and perform westward drift along the planet. This region is well separated by a magnetic shell and has higher average temperatures and lower bulk proton current densities than the surrounding area. On the dayside the population exhibits loss cone distribution function matching the theoretical loss cone angle. The simulation results are in good agreement with in situ observations of MESSENGER's (MErcury Surface Space ENvironment GEochemistry, and Ranging) MAG and FIPS instruments.

  9. Centennial variations in sunspot number, open solar flux and streamer belt width: 3. Modeling

    Science.gov (United States)

    Lockwood, M.; Owens, M. J.

    2014-07-01

    From the variation of near-Earth interplanetary conditions, reconstructed for the mid-19th century to the present day using historic geomagnetic activity observations, Lockwood and Owens (2014) have suggested that Earth remains within a broadened streamer belt during solar cycles when the Open Solar Flux (OSF) is low. From this they propose that the Earth was immersed in almost constant slow solar wind during the Maunder minimum (c. 1650-1710). In this paper, we extend continuity modeling of the OSF to predict the streamer belt width using both group sunspot numbers and corrected international sunspot numbers to quantify the emergence rate of new OSF. The results support the idea that the solar wind at Earth was persistently slow during the Maunder minimum because the streamer belt was broad.

  10. Neptune on tiptoes: dynamical histories that preserve the cold classical Kuiper belt

    CERN Document Server

    Wolff, Schuyler; Murray-Clay, Ruth A

    2011-01-01

    The current dynamical structure of the Kuiper belt was shaped by the orbital evolution of the giant planets, especially Neptune, during the era following planet formation, when the giant planets may have undergone planet-planet scattering and/or planetesimal-driven migration. Numerical simulations of this process, while reproducing many properties of the belt, fail to generate the high inclinations and eccentricities observed for some objects while maintaining the observed dynamically "cold" population. We present the first of a three-part parameter study of how different dynamical histories of Neptune sculpt the planetesimal disk. Here we identify which dynamical histories allow an in situ planetesimal disk to remain dynamically cold, becoming today's cold Kuiper belt population. We find that if Neptune undergoes a period of elevated eccentricity and/or inclination, it secularly excites the eccentricities and inclinations of the planetesimal disk. We demonstrate that there are several well-defined regimes fo...

  11. Drying of HTR fissile and fertile particles and experience with a belt dryer

    International Nuclear Information System (INIS)

    In the fabrication of fissile and fertile material particles for high-temperature reactors, drying of the gel particles is a very important process step. First, the drying properties of ThO2(Th, U)O2 and UO2 gel particles were examined and a belt dryer for continuous drying was developed using the findings obtained. The parameters during examination of the drying properties were: Th/U ratio, content of organic accessory substances, residual concentration of ammonium nitrate, particle size, washing liquid, ageing and drying room atmosphere. The belt dryer developed, having a centre-to-centre distance of 2.5 m and a belt width of 350 mm, can be used for drying approx. 0.8 kg/h of heavy metal oxide particles. The particle residence time in the dryer is only 8 to 13 minutes. (orig.)

  12. Some problems of geologic relations between the Amazon craton and east margins fold belts

    International Nuclear Information System (INIS)

    This paper deals with some geologic problems related to the limits between the Amazon craton and the fold belts developed at its margins during the Precambrian. These limits are diversified but clearly recognized. To the north, the Araguaia-Tocantins fold belt, of presumed Middle Proterozoic age, is separated from the cratonic block by a deep marginal fracture zone permeated by mafic and ultramafic rocks. The geologic, magmatic and aeromagnetic characteristics of this zone point out the presence of deep faults, supposed to be of Middle Proterozoic age. The southern Paraguay fold belt constitutes and accurated zone of linear structures supposed to be of Late Proterozoic development. Despite the great increase of knowledge during the last ten years many tectonic, stratigraphic and geochronologic problems remain unsolved. The aim of this paper is to point out some of these problems and suggest specific studies to solve them. (author)

  13. Design of belt conveyor electric control device based on CC-link bus

    Science.gov (United States)

    Chen, Goufen; Zhan, Minhua; Li, Jiehua

    2016-01-01

    In view of problem of the existing coal mine belt conveyor is no field bus communication function, two levels belt conveyor electric control system design is proposed based on field bus. Two-stage belt conveyor electric control system consists of operation platform, PLC control unit, various sensors, alarm device and the water spraying device. The error protection is realized by PLC programming, made use of CC-Link bus technology, the data share and the cooperative control came true between host station and slave station. The real-time monitor was achieved by the touch screen program. Practical application shows that the system can ensure the coalmine production, and improve the automatic level of the coalmine transport equipment.

  14. Growth of asteroids, planetary embryos and Kuiper belt objects by chondrule accretion

    CERN Document Server

    Johansen, Anders; Lacerda, Pedro; Bizzarro, Martin

    2015-01-01

    Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas-drag-assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo run-away accretion of chondrules within ~3 Myr, forming planetary embryos up to Mars sizes along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size-sorting of chondrules consistent with chondrites. Accretion of mm-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disk life time outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is...

  15. RESEARCH AND PRACTICE ON NONDESTRUCTIVE FLAW DETECTION INSTALLATION FOR WIRE-CORE BELT

    Institute of Scientific and Technical Information of China (English)

    刘志河; 张海涛; 绍庆龙

    1997-01-01

    Electromagnetic self-induction theory and computer are adopted and study of online monitoring technique for wire-core belt is conducted, the study shows that there is direct proportion between distance I of broken ends and output volt V, when I≥60 mm, V keeps constantly, the running speed v of wire-core belt has no big effect on output volt V, there is inverse proportion between the height h from probe to the surface of the belt and output volt V, when h≥30mm, V tends to be zero. Based on the test result, on-line monitoring installation is developed, the practice proved that the accuracy of broken wire monitoring can be above 95%, the monitoring accuracy of joint twitch can be 0.04 V/mm.

  16. Singularity Detection of Magnetic Memory Signal of Steel-Cord Conveyor Belt

    Directory of Open Access Journals (Sweden)

    Qiao Tiezhu

    2013-09-01

    Full Text Available Metal magnetic memory technology was an important method for detecting the steel-cord conveyor belt early fault, characteristics of magnetic memory signal extraction is critical for judging of the conveyor belt failure. Generally using of magnetic memory signal maximum gradient value can quickly judge the stress concentration zone, but the magnetic memory signal is susceptible to effected by environmental and noise; In view of the weak and non-stationary characteristics of magnetic memory signal, this paper has proposed the singularity detection method based on wavelet transform modulus maximum for metal magnetic memory signal, the method could exactly judged the stress concentration zone of joints and located the fault points of the steel-cord belt, the characteristic gradient of magnetic memory signal and the Lipschitz exponent were extracted. The result of simulation indicated the technology was effectively for judging the stress concentration zone and fault point. ��

  17. Combined analysis of land cover change and NDVI trends in the Northern Eurasian grain belt

    Institute of Scientific and Technical Information of China (English)

    Christopher K.WRIGHT; Kirsten M.de BEURS; Geoffrey M.HENEBRY

    2012-01-01

    We present an approach to regional environmental monitoring in the Northern Eurasian grain belt combining time series analysis of MODIS normalized difference vegetation index (NDVI) data over the period 2001-2008 and land cover change (LCC) analysis of the 2001and 2008 MODIS Global Land Cover product (MCD12Q1).NDVI trends were overwhelmingly negative across the grain belt with statistically significant (p ≤ 0.05)positive trends covering only 1% of the land surface.LCC was dominated by transitions between three classes;cropland,grassland,and a mixed cropland/natural vegetation mosaic.Combining our analyses of NDVI trends and LCC,we found a pattern of agricultural abandonment (cropland to grassland) in the southern range of the grain belt coinciding with statistically significant (p≤0.05)negative NDVI trends and likely driven by regional drought.In the northern range of the grain belt we found an opposite tendency toward agricultural intensification; in this case,represented by LCC from cropland mosaic to pure cropland,and also associated with statistically significant (p≤0.05) negative NDVI trends.Relatively small clusters of statistically significant (p ≤ 0.05) positive NDVI trends corresponding with both localized land abandonment and localized agricultural intensification show that land use decision making is not uniform across the region.Land surface change in the Northern Eurasian grain belt is part of a larger pattern of land cover land use change (LCLUC) in Eastern Europe,Russia,and former territories of the Soviet Union following realignment of socialist land tenure and agricultural markets.Here,we show that a combined analysis of LCC and NDVI trends provides a more complete picture of the complexities of LCLUC in the Northern Eurasian grain belt,involving both broader climatic forcing,and narrower anthropogenic impacts,than might be obtained from either analysis alone.

  18. Combined analysis of land cover change and NDVI trends in the Northern Eurasian grain belt

    Science.gov (United States)

    Wright, Christopher K.; de Beurs, Kirsten M.; Henebry, Geoffrey M.

    2012-06-01

    We present an approach to regional environmental monitoring in the Northern Eurasian grain belt combining time series analysis of MODIS normalized difference vegetation index (NDVI) data over the period 2001-2008 and land cover change (LCC) analysis of the 2001 and 2008 MODIS Global Land Cover product (MCD12Q1). NDVI trends were overwhelmingly negative across the grain belt with statistically significant ( p⩽0.05) positive trends covering only 1% of the land surface. LCC was dominated by transitions between three classes; cropland, grassland, and a mixed cropland/natural vegetation mosaic. Combining our analyses of NDVI trends and LCC, we found a pattern of agricultural abandonment (cropland to grassland) in the southern range of the grain belt coinciding with statistically significant ( p⩽0.05) negative NDVI trends and likely driven by regional drought. In the northern range of the grain belt we found an opposite tendency toward agricultural intensification; in this case, represented by LCC from cropland mosaic to pure cropland, and also associated with statistically significant ( p⩽0.05) negative NDVI trends. Relatively small clusters of statistically significant ( p⩽0.05) positive NDVI trends corresponding with both localized land abandonment and localized agricultural intensification show that land use decision making is not uniform across the region. Land surface change in the Northern Eurasian grain belt is part of a larger pattern of land cover land use change (LCLUC) in Eastern Europe, Russia, and former territories of the Soviet Union following realignment of socialist land tenure and agricultural markets. Here, we show that a combined analysis of LCC and NDVI trends provides a more complete picture of the complexities of LCLUC in the Northern Eurasian grain belt, involving both broader climatic forcing, and narrower anthropogenic impacts, than might be obtained from either analysis alone.

  19. Development of green belt for Heavy Water Plant (Manuguru) (Paper No. 4.4)

    International Nuclear Information System (INIS)

    There has been an awakening worldwide regarding environmental degradation. So there is an urgent need of a policy on conservation of ecology while planning projects. Provision for suitable tree plantation as a green belt around a chemical industrial plant is a proven remedy to minimise the impact of gaseous effluents in addition to retain a green cover in the area. This paper describes the steps taken at Heavy Water Plant, Manuguru for providing green belt from a very early stage of execution of the project. (author)

  20. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction.

    Science.gov (United States)

    Gyawu, Rebecca; Quansah, Joseph E; Fall, Souleymane; Gichuhi, Peter N; Bovell-Benjamin, Adelia C

    2015-01-01

    In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs) were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%), restaurants (19.7%), fast food restaurants (16.4%), small supermarkets (8.2%), and large supermarket and farmers' markets (3.3 %), respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p environment had limited opportunities for healthy food choices. PMID:26844138

  1. Crustal scale geometry of the Zagros fold–thrust belt, Iran

    OpenAIRE

    McQuarrie, Nadine

    2004-01-01

    Balanced cross-sections across the Zagros fold–thrust belt in Iran are used to analyze the geometry of deformation within the sedimentary cover rocks, and to test the hypothesis of basement involved thrusting throughout the fold–thrust belt. Although the Zagros deformation front is a relatively rectilinear feature, the sinuous map-view morphology of the mountain front is a result of a 6 km structural step in the regional elevation of the Asmari Limestone that produces a pronounced step in top...

  2. Willingness to use safety belt and levels of injury in car accidents

    OpenAIRE

    DE LAPPARENT, M

    2008-01-01

    In this article, we develop a bivariate ordered Probit model to analyze the decision to fasten the safety belt in a car and the resulting severity of accidents if it happens. The approach takes into account the fact that the decision to fasten the safety belt has a direct causal effect on the category of injury if an accident happens. Our application to a sample drawn from the database of French accident reports in 2003 for three populations of car users (drivers, front passengers, rear passe...

  3. Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt System

    CERN Document Server

    Ade, P A R; Alves, M I R; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartlett, J G; Battaner, E; Bedini, L; Benabed, K; Benoît, A; Bernard, J -P; Bersanelli, M; Bonaldi, A; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Burigana, C; Butler, R C; Chen, X; Chiang, L -Y; Christensen, P R; Clements, D L; Colombi, S; Colombo, L P L; Coulais, A; Cuttaia, F; Davies, R D; Davis, R J; de Bernardis, P; de Zotti, G; Delabrouille, J; Dickinson, C; Diego, J M; Dobler, G; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Enßlin, T A; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Génova-Santos, R T; Ghosh, T; Giard, M; Giardino, G; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gregorio, A; Gruppuso, A; Hansen, F K; Harrison, D; Hernández-Monteagudo, C; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Jaffe, T R; Jaffe, A H; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Lawrence, C R; Leach, S; Leonardi, R; Lilje, P B; Linden-Vørnle, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Massardi, M; Matarrese, S; Mazzotta, P; Melchiorri, A; Mennella, A; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Pajot, F; Paladini, R; Paoletti, D; Peel, M; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Popa, L; Poutanen, T; Pratt, G W; Prunet, S; Puget, J -L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Renault, C; Ricciardi, S; Ristorcelli, I; Rocha, G; Rosset, C; Rubiño-Martín, J A; Rusholme, B; Salerno, E; Sandri, M; Savini, G; Scott, D; Spencer, L; Stolyarov, V; Sudiwala, R; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Tibbs, C T; Toffolatti, L; Tomasi, M; Tristram, M; Valenziano, L; Van Tent, B; Varis, J; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Ysard, N; Yvon, D; Zacchei, A; Zonca, A

    2013-01-01

    We perform an analysis of the diffuse low-frequency Galactic components in the Southern part of the Gould Belt system ($130^\\circ\\leq l\\leq 230^\\circ$ and $-50^\\circ\\leq b\\leq -10^\\circ$). Strong UV flux coming from the Gould Belt super-association is responsible for bright diffuse foregrounds that we observe from our position inside the system and that can help us improve our knowledge of the Galactic emission. Free-free emission and anomalous microwave emission (AME) are the dominant components at low frequencies ($\

  4. Age constraints of the Wassa and Benso mesothermal gold deposits, Ashanti Belt, Ghana, West Africa

    Science.gov (United States)

    Parra-Avila, Luis A.; Bourassa, Yan; Miller, John; Perrouty, Stéphane; Fiorentini, Marco L.; Campbell McCuaig, T.

    2015-12-01

    The Ashanti Belt in Ghana hosts numerous multi-million ounce gold deposits and is one of the most richly gold endowed Paleoproterozoic belts of the West African Craton. This work shows that the Wassa mineralized intrusion is part of the Sefwi Group. This unit at Wassa is strongly magnetic and show a distinctly high response in regional magnetic data sets compared to other units of equivalent age within the belt. The unit is inferred to be a lateral extension of an exposed fragment of what defines the substrate to the Tarkwa Basin sediments. The Wassa deposit, located in the eastern limb of the belt, is hosted within mafic to intermediate volcanic flows that are interbedded with minor horizons of volcaniclastics, clastic sediments. The clastic sediments include wackes and magnetite rich sedimentary layers, presumably derived from banded iron formations. The previously described sequence is intruded by syn-volcanic mafic intrusives and felsic porphyries rocks that are all part of the Birimian stratigraphy. Two new key SHRIMP II U-Pb ages were determined as part of this study: a new age of 2191 ± 6 Ma was determined on magmatic zircon grains of the Wassa porphyry host rock, which now represents the oldest known felsic intrusion hosting gold mineralization in the Ashanti Belt region. The Benso gold deposit system, which is located in the eastern limb of the Ashanti Belt approximately 38 km southwest of Wassa is hosted within a series of volcanic units intruded by mafic to intermediate units. A SHRIMP II U-Pb age of 2157 ± 5 Ma was determined from magmatic zircons obtained from a granodiorite of the G-Zone of the Benso deposit. This granodiorite is the main host rock for gold mineralization and thus the age provides an upper constraint for mineral emplacement. The newly determined ages provide an upper constraint for the gold mineralization within this region of the Ashanti Belt. They also support recent structural studies that have interpreted that the Wassa

  5. Primary Seat-Belt Laws and Driver Behavior: Evidence from Accident Data

    OpenAIRE

    Bae, Yong-Kyun

    2013-01-01

    This paper investigates the offsetting effect theory, using individual-level accident data to analyze how drivers respond to seat-belt laws. I find that drivers drive their vehicles more carefully when more stringent seat-belt laws are in effect. I also find that careful driving is not associated with pedestrian involvement in accidents. Using synthetic panel data, I find that the change in the laws results in an increased number of careful drivers and a decreased number of careless drivers i...

  6. The "One Belt and One Road" is a Strategy to Optimize Regional Pattern Focus

    Institute of Scientific and Technical Information of China (English)

    Li; Boya

    2015-01-01

    "We should focus on implementation of the three grand strategies,i.e.build the One Belt and One Road,Beijing-Tianjin-Hebei collaborative development,and the Yangtze River Economic Belt,and strive for a good start the next year".The just completed Central Economic Work Conference lists"the optimization of economic spatial development"as one of the five major tasks for economic work in 2015.After last year’s Central Economic Work Conference proposed to push forward building

  7. An Experimental Approach Towards the Evaluation of a Seat Belt Campaign With an Inside View on the Psychology Behind Seat Belt Use

    OpenAIRE

    Brijs, Kris; DANIELS, Stijn; Brijs, Tom; Wets, Geert

    2010-01-01

    A Belgian national safety belt campaign was evaluated by means of a questionnaire survey in a student sample. The evaluation was done through a three group after-only design with the use of one control group and two experimental groups. The first experimental group, the attentive group, was exposed to the campaign material in a very direct, attentive way, whereas the second experimental group, the pre-attentive group, was exposed rather inattentively. The framework of the Theory of Planned Be...

  8. The Russell gold deposit, Carolina Slate Belt, North Carolina

    Science.gov (United States)

    Klein, T.L.; Cunningham, C.G.; Logan, M.A.V.; Seal, R.R.

    2007-01-01

    Gold deposits have been mined in the Carolina slate belt from the early 1800s to recent times, with most of the production from large mines in South Carolina. The Russell mine, one of the larger producers in North Carolina, is located in the central Uwharrie Mountains, and produced over 470 kg of gold. Ore grades averaged about 3.4 grams per tonne (g/ t), with higher-grade zones reported. The Russell deposit is interpreted to be a sediment-hosted, gold-rich, base-metal poor, volcanogenic massive sulfide deposit in which gold was remobilized, in part, during Ordovician metamorphism. The ore was deposited syngenetically with laminated siltstones of the late Proterozoic Tillery Formation that have been metamorphosed to a lower greenschist facies. The Tillery Formation regionally overlies subaerial to shallow marine rhyolitic volcanic and volcaniclastic rocks of the Uwharrie Formation and underlies the marine volcanic and sedimentary rocks of the Cid Formation. Recent mapping has shown that a rhyolitic dome near the Russell mine was extruded during the deposition of the lower part of the Tillery Formation, at about the same time as ore deposition. Relict mafic, rock fragments present in the ore zones suggest contemporaneous bimodal (rhyolite-basalt) volcanism. The maximum formation age of the Russell deposit is younger than 558 Ma, which is similar to that of the larger, well known Brewer, Haile, and Ridgeway deposits of South Carolina. Gold was mined from at least six zones that are parallel to the regional metamorphic foliation. These strongly deformed zones consist of northeast-trending folds, high-angle reverse faults, and asymmetric doubly plunging folds overturned to the southeast. The dominant structure at the mine is an asymmetric doubly plunging anticline with the axis trending N 45?? E, probably related to late Ordovician (456 ?? 2 Ma) regional metamorphism and deformation. Two stages of pyrite growth are recognized. Stage 1, primary, spongy pyrite, is

  9. The effects of enforcement and rewards on safety-belt use : a field study in The Netherlands.

    NARCIS (Netherlands)

    Hagenzieker, M.P.

    1990-01-01

    It turns out that young male drivers aged between 18 and 25 use their safety belt less often than other driver groups in The Netherlands. For this reason, it was decided to conduct a nationwide campaign to promote safety belt use by military personnel during October and November 1988. The campaign w

  10. Triton's surface age and impactor population revisited in light of Kuiper Belt fluxes Evidence for small Kuiper Belt objects and recent geological activity

    CERN Document Server

    Stern, S A

    1999-01-01

    Neptune's largest satellite, Triton, is one of the most fascinating and enigmatic bodies in the solar system. Among its numerous interesting traits, Triton appears to have far fewer craters than would be expected if its surface was primordial. Here we combine the best available crater count data for Triton with improved estimates of impact rates by including the Kuiper Belt as a source of impactors. We find that the population of impactors creating the smallest observed craters on Triton must be sub-km in scale, and that this small-impactor population can be best fit by a differential power-law size index near -3. Such results provide interesting, indirect probes of the unseen small body population of the Kuiper Belt. Based on the modern, Kuiper Belt and Oort Cloud impactor flux estimates, we also recalculate estimated ages for several regions of Triton's surface imaged by Voyager 2, and find that Triton was probably active on a time scale no greater than 0.1-0.3 Gyr ago (indicating Triton was still active af...

  11. The General Geology of the Kruger National Park

    Directory of Open Access Journals (Sweden)

    I.C. Schutte

    1986-12-01

    Full Text Available Geological units and new data gathered during regional mapping of the Kruger National Park are summarised. A simplified geological map is presented in conjunction with this paper. A large number of new geological formations have been recognised in the course of this regional mapping and new names have been proposed for these units. Some of these names have not yet been officially recognised by the South African Committee for Stratigraphy (SACS. On-going work by the Geological Survey and other organisations is likely to lead to further additions to and refinement of the data presented in this paper. The Goudplaats and Makhutswi Gneisses are the oldest rocks known in the park. They form the sialic basement of the various greenstone belts represented by the Murchison and Barberton sequences. The age relations of the Orpen Gneiss* have not yet been established. Tonalitic and trondjemitic gneisses constitute the first phase of intrusion of the Nelspruit Granite Suite. The Shamiriri, Macetse* and Baderoukwe Granites, and the Cunning Moor Tonalite* intrudes rocks of Swazian age during the succeeding Randian Erathem. At the commencement of the Mokolian Erathem syenite of the Phalaborwa Complex intruded the Makhutswi Gneiss. Subsequently extrusion of lavas and deposition of sediments of the Soutpansberg Group of Mokolian age took place in a fault-bounded trough in the northern part of the park. Diabase intruded the Group in the form of sills. Pre-Karoo dykes of various ages occur throughout the area. The Timbavati Gabbro represents the youngest Pre-Karoo intrusion. The Late Palaeozoic to Mesozoic Karoo Sequence extends from north to south along the eastern edge of the park and consists of sedimentary rocks overlain by basalt and rhyolite. The last phase of Karoo volcanism is represented by granophyre, gabbro and microgranite. The sedimentary Malvernia Formation of Cretaceous age unconformably overlies the basalt in the northern part of the park

  12. Evaluating the earliest traces of Archean sub-seafloor life by NanoSIMS

    Science.gov (United States)

    Mcloughlin, N.; Grosch, E. G.; Kilburn, M.; Wacey, D.

    2012-12-01

    The Paleoarchean sub-seafloor has been proposed as an environment for the emergence of life with titanite microtextures in pillow lavas argued to be the earliest traces of microbial micro-tunneling (Furnes et al. 2004). Here we use a nano-scale ion microprobe (NanoSIMS) to evaluate possible geochemical traces of life in 3.45 Ga pillow lavas of the Barberton Greenstone Belt, South Africa. We investigated both surface and drill core samples from the original "Biomarker" outcrop in the Hooggenoeg Fm. Pillow lava metavolcanic glass contain clusters of segmented microcrystalline titanite filaments, ~4μm across and inclusions in the microtextures have strongly depleted δ34SVCDT values of -39.8 to +3.2‰ (n= 32). The magnitude, range and spatial heterogeneity of these δ34S values are consistent with an early microbial origin (McLoughlin et al. 2012). In contrast, sulfides cross-cutting the microtextures related to later veining have positive δ34S of +6.7 to +18.0‰ (n=20). These data can be compared to magmatic sulfides (δ34S = +3±3‰), Archean seawater (δ34S ca. +5‰) and Archean sedimentary sulfides (δ34S = +8 to -23‰). We propose that the Hooggenoeg sulfides probably formed during early fluid-rock-microbe interaction involving sulfate-reducing microbes (c.f. Rouxel et al. 2008). The pillow lavas were then metamorphosed, the glass transformed to a greenschist facies assemblage and titanite growth encapsulated the microbial sulfides. In summary, the extreme sulfur isotope fractionations reported here independently point towards the potential involvement of microbes in the alteration of Archean volcanic glass. In situ sulfur isotope analysis of basalt-hosted sulfides may provide an alternative approach to investigating the existence of an Archean sub-seafloor biosphere that does not require the mineralization of early microbial microborings with organic linings.

  13. National Coral Reef Monitoring Program: Assessment of coral reef communities in U.S. Virgin Islands (USVI) using the Belt Transect fish census method

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Belt Transect method is used to conduct fish surveys in the U.S. Virgin Islands (USVI) as part of the National Coral Reef Monitoring Program (NCRMP). The Belt...

  14. Determining the spectra of radiation belt electron losses: Fitting DEMETER electron flux observations for typical and storm times

    Science.gov (United States)

    Whittaker, Ian C.; Gamble, Rory J.; Rodger, Craig J.; Clilverd, Mark A.; Sauvaud, Jean-André

    2013-12-01

    The energy spectra of energetic electron precipitation from the radiation belts are studied in order to improve our understanding of the influence of radiation belt processes. The Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) microsatellite electron flux instrument is comparatively unusual in that it has very high energy resolution (128 channels with 17.9 keV widths in normal survey mode), which lends itself to this type of spectral analysis. Here electron spectra from DEMETER have been analyzed from all six years of its operation, and three fit types (power law, exponential, and kappa-type) have been applied to the precipitating flux observations. We show that the power law fit consistently provides the best representation of the flux and that the kappa-type is rarely valid. We also provide estimated uncertainties in the flux for this instrument as a function of energy. Average power law gradients for nontrapped particles have been determined for geomagnetically nondisturbed periods to get a typical global behavior of the spectra in the inner radiation belt, slot region, and outer radiation belt. Power law spectral gradients in the outer belt are typically -2.5 during quiet periods, changing to a softer spectrum of ˜-3.5 during geomagnetic storms. The inner belt does the opposite, hardening from -4 during quiet times to ˜-3 during storms. Typical outer belt e-folding values are ˜200 keV, dropping to ˜150 keV during geomagnetic storms, while the inner belt e-folding values change from ˜120 keV to >200 keV. Analysis of geomagnetic storm periods show that the precipitating flux enhancements evident from such storms take approximately 13 days to return to normal values for the outer belt and slot region and approximately 10 days for the inner belt.

  15. Search for Water in Outer Main Belt Based on AKARI Asteroid Catalog

    Science.gov (United States)

    Usui, Fumihiko

    2012-06-01

    We propose a program to search water ice on the surface of asteroids in the outer main belt regions, which have high albedo measured with AKARI. The distribution of water in the main belt provides important information to understanding of the formation and evolution of the solar system, because water is a good indicator of temperature in the early solar nebula. The existence of water ice is a hot topic in the solar system studies today. Water ice is recently found in the outer region of the main asteroid belt and some of them are linked to the main belt comets. Brand-new albedo data brought by AKARI opens the possibility of detection of water ice on the C-type asteroids. Here we propose to make the spectroscopic observations with the Subaru telescope in the near-infrared wavelengths to detect water ice on these high-albedo C-type asteroids. Thanks to a large aperture of Subaru telescope and a high altitude of Mauna Kea, it can be only possible to observe a weak signal of the existence of water on the surface of asteroids with a certain S/N. In addition, using the imaging data taken prior to IRCS spectroscopic mode, we intend to seek any comet-like activities by investigating diffuseness of the asteroids, which can be detected by comparing the observed point-spread functions with those of field stars.

  16. Economic analysis of deforestation : the case of the gum Arabic belt in Sudan

    NARCIS (Netherlands)

    Rahim, A.

    2006-01-01

    Keywords: Gum Arabic; Deforestation; Entry and Exit; Real options Drought; Socio-economic, Oligopoly; Interdependent markets; Stackelberg.The gum arabic belt inSudanoffered in the past an examp

  17. Active Prompting to Decrease Cell Phone Use and Increase Seat Belt Use while Driving

    Science.gov (United States)

    Clayton, Michael; Helms, Bridgett; Simpson, Cathy

    2006-01-01

    Automobile crashes are the leading cause of death for those aged 3 to 33, with 43,005 (118 per day) Americans killed in 2002 alone. Seat belt use reduces the risk of serious injury in an accident, and refraining from using a cell phone while driving reduces the risk of an accident. Cell phone use while driving increases accident rates, and leads…

  18. 77 FR 19155 - Federal Motor Vehicle Safety Standards; Seat Belt Assembly Anchorages; Incorporation by Reference

    Science.gov (United States)

    2012-03-30

    ... published on April 11, 2000 (65 FR 19477-78). FOR FURTHER INFORMATION CONTACT: For non-legal issues: Ms... the FAD is acceptable. In comparison, FMVSS No. 208, ``Occupant crash protection,'' at S10.4.2.1... NPRM that, among other matters, proposed to require passenger seat belts on motorcoaches (75 FR...

  19. 49 CFR 571.209 - Standard No. 209; Seat belt assemblies.

    Science.gov (United States)

    2010-10-01

    ....1 of Standard No. 208 (49 CFR 571.208) by virtue of S4.1.2.1(c)(2) of Standard No. 208 does not have... Motor Vehicle Safety Standards § 571.209 Standard No. 209; Seat belt assemblies. S1. Purpose and scope.... S3. Definitions. Adjustment hardware means any or all hardware designed for adjusting the size of...

  20. Uranium deposits of the Grants, New Mexico mineral belt (II). [Genesis

    Energy Technology Data Exchange (ETDEWEB)

    Brookins, D.G.

    1979-07-01

    This is part of a study of the genesis of the U deposits of the Grants mineral belt. Enrichment of Mg in ore zones is frequently observed, with chlorite being a common product. Clay mineralogic studies argue for chlorite-illite-montmorillonite associations with ores. The methods include scanning electron microscopy, Eh-pH diagrams, activation analysis, and rare earth element studies. (DLC)

  1. Improving the Salammbo code modelling and using it to better predict radiation belts dynamics

    Science.gov (United States)

    Maget, Vincent; Sicard-Piet, Angelica; Grimald, Sandrine Rochel; Boscher, Daniel

    2016-07-01

    In the framework of the FP7-SPACESTORM project, one objective is to improve the reliability of the model-based predictions performed of the radiation belt dynamics (first developed during the FP7-SPACECAST project). In this purpose we have analyzed and improved the way the simulations using the ONERA Salammbô code are performed, especially in : - Better controlling the driving parameters of the simulation; - Improving the initialization of the simulation in order to be more accurate at most energies for L values between 4 to 6; - Improving the physics of the model. For first point a statistical analysis of the accuracy of the Kp index has been conducted. For point two we have based our method on a long duration simulation in order to extract typical radiation belt states depending on the solar wind stress and geomagnetic activity. For last point we have first improved separately the modelling of different processes acting in the radiation belts and then, we have analyzed the global improvements obtained when simulating them together. We'll discuss here on all these points and on the balance that has to be taken into account between modeled processes to globally improve the radiation belt modelling.

  2. Economic performance of alternative tillage systems in the northern Corn Belt

    Science.gov (United States)

    While no-till (NT) cropping systems can provide conservation benefits in the northern Corn Belt, adoption has been low due to concerns about potential yield reductions and economic risk. Strip-tillage (ST) systems have been proposed as an alternative that may provide many of the conservation benefit...

  3. Dynamical evolution of V-type photometric candidates in the outer Main-belt

    CERN Document Server

    Huaman, Mariela E; Domingos, Rita Cassia

    2014-01-01

    V-type asteroids, characterized by two absorption bands at 1.0 and 2.0 $\\mu m$, are usually thought to be portions of the crust of differentiated or partially differentiated bodies. Most V-type asteroids are found in the inner main belt and are thought to be current or past members of the Vesta dynamical family. Recently, several V-type photometric candidates have been identified in the central and outer main belt. While the dynamical evolution of V-type photometric candidates in the central main belt has been recently investigated, less attention has been given to the orbital evolution of basaltic material in the outer main belt as a whole. Here we identify known and new V-type photometric candidates in this region, and study their orbital evolution under the effect of gravitational and non-gravitational forces. A scenario in which a minimum of three local sources, possibly associated with the parent bodies of (349) Dembowska, (221) Eos, and (1459) Magnya, could in principle explain the current orbital distr...

  4. Water-ice-driven Activity on Main-Belt Comet P/2010 A2 (LINEAR)?

    DEFF Research Database (Denmark)

    Moreno, Fernando; Licandro, Javier; Tozzi, Gian-Paolo;

    2010-01-01

    The dust ejecta of Main-Belt Comet P/2010 A2 (LINEAR) have been observed with several telescopes at the Observatorio del Roque de los Muchachos on La Palma, Spain. Application of an inverse dust tail Monte Carlo method to the images of the dust ejecta from the object indicates that a sustained, l...

  5. Walking Flexibility after Hemispherectomy: Split-Belt Treadmill Adaptation and Feedback Control

    Science.gov (United States)

    Choi, Julia T.; Vining, Eileen P. G.; Reisman, Darcy S.; Bastian, Amy J.

    2009-01-01

    Walking flexibility depends on use of feedback or reactive control to respond to unexpected changes in the environment, and the ability to adapt feedforward or predictive control for sustained alterations. Recent work has demonstrated that cerebellar damage impairs feedforward adaptation, but not feedback control, during human split-belt treadmill…

  6. Age and sedimentary record of inland eolian sediments in Lithuania, NE European Sand Belt

    DEFF Research Database (Denmark)

    Kalińska-Nartiša, Edyta; Thiel, Christine; Nartišs, Maris;

    2015-01-01

    We present a study based on four inland eolian locations in Eastern, Central and Southeastern Lithuania belonging to the northeastern part of the 'European Sand Belt' (ESB). Although there have been several previous studies of the ESB, this north-eastern extension has not been investigated before...

  7. Crop advisor perceptions of giant ragweed distribution, herbicide-resistance, and management in the Corn Belt

    Science.gov (United States)

    Giant ragweed has been increasing as a major weed of row crops in North America. We conducted a web-based survey of Certified Crop Advisors in the Corn Belt to determine the current distribution of giant ragweed, the distribution of herbicide resistant populations, and management and ecological fact...

  8. Salt-related structural styles of Kuqa foreland fold belt, northern Tarim basin

    Institute of Scientific and Technical Information of China (English)

    TANG; Liangjie; JIA; Chengzao; PI; Xuejun; CHEN; Suping; W

    2004-01-01

    The salt beds of Lower Tertiary developed in the mid-segment of Kuqa foreland fold belt, northern Tarim basin. They considerably controlled structural deformation of the belt.According to the field observation, seismic profile interpretation and drilling data, three different structural styles of supra-salt, intra-salt and sub-salt occurred in the Kuqa foreland fold belt. Supra-salt structural styles mainly include thrust faults and fault-related sags. Intra-slat structural styles essentially are salt-pillows, intra-salt faults and folds, and salt weld structures. Sub-salt structural styles mainly consist of imbricated thrust faults, duplex structures, pop-up and fault-related folds. It is indicated that great differences exist among supra-salt, intra-salt and sub-salt structures of Kuqa foreland fold belt. The salt-related structures were formed in the same structural stress field. The dynamic mechanism of the salt-related structures is mainly associated with gravitation, compression and plastic flow of salt beds.

  9. Stability of organic matter in soils of the Belgium Loess Belt upon erosion and deposition

    NARCIS (Netherlands)

    X. Wang; E. Cammeraat; Z. Wang; G. Govers; K. Kalbitz

    2011-01-01

    Stability of organic matter in soils of the Belgium Loess Belt upon erosion and deposition X. Wang, L.H. Cammeraat, Z. Wang, G. Govers, K. Kalbitz. Abstract: Soil erosion has significant impacts on terrestrial C dynamics, which removes C from topsoil and continually exposes subsoil that has lower C

  10. Clay minerals assemblage in the Neogene fluvial succession of the Pishin Belt, Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Akhtar Muhammad; Friis, Henrik;

    2014-01-01

    The Neogene siliciclastic succession of the Pishin Belt comprises the newly proposed Middle to Upper Miocene Dasht Murgha group, Miocene-Pliocene Malthanai formation and Pleistocene Bostan Formation. Sandstones of the succession have been classified as lithic arenites and their detrital modes ind...

  11. New investigations in southwestern Guinea: consequences for the Rokelide belt (West Africa)

    Science.gov (United States)

    Villeneuve, Michel; Bellon, Hervé; Corsini, Michel; Le Metour, Joël; Chatelee, Sébastien

    2015-07-01

    The southern Guinean terranes belong to the "Rokelide belt" that is located in the southwestern part of the West African craton (Senegal to Liberia). Field investigations and K-Ar and 40Ar-39Ar radiometric analysis performed on samples collected from southern Guinea provide a new interpretation for metamorphic terranes not yet dated. A K-Ar whole-rock age of a gneiss and 40Ar-39Ar plateau ages of amphiboles separated from a mylonitic gneiss of the Ouankifondi formation and a gneiss from the Kissi-Kissi formation yield several Pan-African metamorphic ages at circa 650, 560, and 530 Ma, respectively. Field investigations show that these formations are unconformably capped by the Kolente group. The previous structural framework and the geodynamic evolution of the Rokelide belt based on the coeval evolution of the Ouankifondi and Kissi-Kissi formations and the Kolente group are reassessed. The Rokelide belt is linked to the Bassaride belt. Correlations with adjacent Sierra Leonean terranes and with northern Guinea and Senegal are considered.

  12. Tianyi Copper Corporation Copper Belt Project Expected to Start in June

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>The copper belt project initiated by Zhongshan Tianyi Copper Corporation is now under construction. Construction of plant is nearing completion and the installation of equipment will soon begin.According to the schedule,the project is expected to begin operation in June, and the output is expected to reach 30,000 tons by end of year.

  13. 14 CFR 91.107 - Use of safety belts, shoulder harnesses, and child restraint systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Use of safety belts, shoulder harnesses, and child restraint systems. 91.107 Section 91.107 Aeronautics and Space FEDERAL AVIATION... was approved by the FAA through Type Certificate or Supplemental Type Certificate. (iv) That the...

  14. 76 FR 36890 - Clarification of Prior Interpretations of the Seat Belt and Seating Requirements for General...

    Science.gov (United States)

    2011-06-23

    ... Printing Office's Web page at http://www.gpoaccess.gov/fr/index.html . You can also get a copy by sending a... belt properly secured about him.'' 36 FR 12511 (July 1, 1971). The FAA has previously interpreted this... Airplane Flight Manual (14 CFR Sec. 23.1581(j)). See 36 FR 12511; see also 14 CFR 23.562, 23.785;...

  15. An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela

    Science.gov (United States)

    Schenk, Christopher J.; Cook, Troy A.; Charpentier, Ronald R.; Pollastro, Richard M.; Klett, Timothy R.; Tennyson, Marilyn E.; Kirschbaum, Mark A.; Brownfield, Michael E.; Pitman, Janet K.

    2009-01-01

    The Orinoco Oil Belt Assessment Unit of the La Luna-Quercual Total Petroleum System encompasses approximately 50,000 km2 of the East Venezuela Basin Province that is underlain by more than 1 trillion barrels of heavy oil-in-place. As part of a program directed at estimating the technically recoverable oil and gas resources of priority petroleum basins worldwide, the U.S. Geological Survey estimated the recoverable oil resources of the Orinoco Oil Belt Assessment Unit. This estimate relied mainly on published geologic and engineering data for reservoirs (net oil-saturated sandstone thickness and extent), petrophysical properties (porosity, water saturation, and formation volume factors), recovery factors determined by pilot projects, and estimates of volumes of oil-in-place. The U.S. Geological Survey estimated a mean volume of 513 billion barrels of technically recoverable heavy oil in the Orinoco Oil Belt Assessment Unit of the East Venezuela Basin Province; the range is 380 to 652 billion barrels. The Orinoco Oil Belt Assessment Unit thus contains one of the largest recoverable oil accumulations in the world.

  16. Agricultural production and nutrient runoff in the Corn Belt: Assessing dynamic environmental performance

    Science.gov (United States)

    Agricultural production in the Corn Belt region of the Upper Mississippi River Basin (UMRB) remains a leading source of nitrogen runoff that contributes to the annual hypoxic 'Dead Zone' in the Gulf of Mexico. The rise of corn production, land conversion, and fertilizer use in re...

  17. Dual task effects for asymmetric stepping on a split-belt treadmill.

    NARCIS (Netherlands)

    McFadyen, B.J.; Hegeman, J.; Duysens, J.E.J.

    2009-01-01

    Bilaterally asymmetric stepping during walking is common to a number of pathological gaits (e.g., hemiplegia, limping). In the present work, the attention level of asymmetric stepping was studied by having subjects walk on a split-belt treadmill with symmetric (2 km/h) and asymmetric (2 km/h vs 4 km

  18. Terrestrial Planet Formation Constrained by Mars and the Structure of the Asteroid Belt

    CERN Document Server

    Izidoro, André; Morbidelli, Alessandro; Winter, Othon C

    2015-01-01

    Reproducing the large Earth/Mars mass ratio requires a strong mass depletion in solids within the protoplanetary disk between 1 and 3 AU. The Grand Tack model invokes a specific migration history of the giant planets to remove most of the mass initially beyond 1 AU and to dynamically excite the asteroid belt. However, one could also invoke a steep density gradient created by inward drift and pile-up of small particles induced by gas-drag, as has been proposed to explain the formation of close-in super Earths. Here we show that the asteroid belt's orbital excitation provides a crucial constraint against this scenario for the Solar System. We performed a series of simulations of terrestrial planet formation and asteroid belt evolution starting from disks of planetesimals and planetary embryos with various radial density gradients and including Jupiter and Saturn on nearly circular and coplanar orbits. Disks with shallow density gradients reproduce the dynamical excitation of the asteroid belt by gravitational s...

  19. Understanding the Dynamical Evolution of the Earth Radiation Belt and Ring Current Coupled System

    Science.gov (United States)

    Shprits, Yuri; Usanova, Maria; Kellerman, Adam; Drozdov, Alexander

    2016-07-01

    Modeling and understanding the ring current and radiation belt-coupled system has been a grand challenge since the beginning of the space age. In this study we show long-term simulations with a 3D Versatile Electron Radiation Belt (VERB) code of modeling the radiation belts with boundary conditions derived from observations around geosynchronous orbit. Simulations can reproduce long term variations of the electron radiation belt fluxes and show the importance of local acceleration, radial diffusion, loss to the atmosphere and loss to the magnetopause. We also present 4D VERB simulations that include convective transport, radial diffusion, pitch angle scattering and local acceleration. VERB simulations show that the lower energy inward transport is dominated by the convection and higher energy transport is dominated by the diffusive radial transport. We also show that at energies of 100s of keV, a number of processes work simultaneously, including convective transport, radial diffusion, local acceleration, loss to the loss cone and loss to the magnetopause. The results of the simulation of the March 2013 storm are compared with Van Allen Probes observations.

  20. An icy Kuiper-Belt around the young solar-type star HD 181327

    CERN Document Server

    Lebreton, J; Thi, W -F; Roberge, A; Donaldson, J; Schneider, G; Maddison, S T; Ménard, F; Riviere-Marichalar, P; Mathews, G S; Kamp, I; Pinte, C; Dent, W R F; Barrado, D; Duchêne, G; Gonzalez, J -F; Grady, C A; Meeus, G; Pantin, E; Williams, J P; Woitke, P

    2011-01-01

    HD 181327 is a young F5/F6V star belonging to the Beta Pictoris moving group (12 Myr). It harbors an optically thin belt of circumstellar material at 90 AU. We aim to study the dust properties in the belt in details, and to constrain the gas-to-dust ratio. We obtained far-IR observations with the Herschel/PACS instrument, and 3.2 mm observations with the ATCA array. The geometry of the belt is constrained with newly reduced HST/NICMOS images that break the degeneracy between the disk geometry and the dust properties. We use the radiative transfer code GRaTer to compute a large grid of models, and we identify the grain models that best reproduce the Spectral Energy Distribution through a Bayesian analysis. We attempt to detect the [OI] and [CII] lines with PACS spectroscopy, providing observables to our photochemical code ProDiMo. The HST observations confirm that the dust is confined in a narrow belt. The continuum is detected in the far-IR with PACS and the disk is resolved with both PACS and ATCA. A medium ...

  1. The secular evolution of the Kuiper belt after a close stellar encounter

    CERN Document Server

    Punzo, D; Zwart, S Portegies

    2014-01-01

    We show the effects of the perturbation caused by a passing by star on the Kuiper belt objects (KBOs) of our Solar System. The Kuiper belt is sampled using up to 131,072 bodies on nearly circular orbits distributed in a ring of surface density $\\Sigma \\sim r^{-2}$. The dynamics of the KB is followed by direct $N$- body simulations. The growth of a dynamically hot population as well as the population in resonance orbits with the planets, depends on the distribution of individual masses of Kuiper belt objects, the total mass and its radial extent, as well as on the mass and the orbit of the passing by star. The Kuiper belt is rather fragile for an encounter with a passing star, and the cross section threshold above which a recognizable structure is left are quite small. We chose for the encountering star a mass 0.5 MSun, to 2 MSun, with an impact parameter of 170 AU (for a 0.5 MSun star) to 220 AU (for 2 MSun) and an inclination angle ($\\theta$) of $60^\\circ$ (for 0.5 MSun) to $120^\\circ$ (for 2 MSun). This res...

  2. Bearing Capacity Analyses for the Great Belt East Bridge Anchor Blocks

    DEFF Research Database (Denmark)

    Sørensen, Carsten Steen; Clausen, Carl J. Frimann; Andersen, Henrik

    1993-01-01

    This paper presents a comparison between different methods of bearing capacity analyses: Upper Bound Method. Limit Equilibrium Analysis and Finite Element Analysis. For the Great Belt East Bridge anchor blocks it was concluded that these methods of calculation agree within 5%. However, for cases...... where the bearing capacity is dominated by frictional materials, much higher differences should be expected....

  3. Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives

    NARCIS (Netherlands)

    Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2010-01-01

    Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives, in the absence or presence of food debris from meat, fish and vegetables and at temperatures of 10, 25 and 37 °C was investigated. The pathogen survived best at 10 °C, and better at 25 °C than at

  4. A ring as a model of the main belt in planetary ephemerides

    CERN Document Server

    Kuchynka, P; Fienga, A; Manche, H; 10.1051/0004-6361/200913346

    2010-01-01

    We assess the ability of a solid ring to model a global perturbation induced by several thousands of main-belt asteroids. The ring is first studied in an analytical framework that provides an estimate of all the ring's parameters excepting mass. In the second part, numerically estimated perturbations on the Earth-Mars, Earth-Venus, and Earth-Mercury distances induced by various subsets of the main-belt population are compared with perturbations induced by a ring. To account for large uncertainties in the asteroid masses, we obtain results from Monte Carlo experiments based on asteroid masses randomly generated according to available data and the statistical asteroid model. The radius of the ring is analytically estimated at 2.8 AU. A systematic comparison of the ring with subsets of the main belt shows that, after removing the 300 most perturbing asteroids, the total main-belt perturbation of the Earth-Mars distance reaches on average 246 m on the 1969-2010 time interval. A ring with appropriate mass is able ...

  5. Impacts of intense inward and outward ULF wave radial diffusion on the Van Allen belts

    Science.gov (United States)

    Mann, Ian; Ozeke, Louis; Rae, I. Jonathan; Murphy, Kyle

    2016-07-01

    During geomagnetic storms, the power in ultra-low frequency (ULF) waves can be orders of magnitude larger than that predicted by statistics determined from an entire solar cycle. This is especially true during the main phase and early recovery phase. These periods of enhanced storm-time ULF wave power can have significant impacts on the morphology and structure of the Van Allen belts. Either fast inward or outward radial diffusion can result, depending on the profiles of the electron phase space density and the outer boundary condition at the edge of the belts. Small changes in the time sequence of powerful ULF waves, and the time sequence of any magnetopause shadowing or the recovery of plamasheet sources relative to the ULF wave occurrence, have a remarkable impact on the resulting structure of the belts. The overall impact of the enhanced ULF wave power is profound, but the response can be very different depending on the available source flux in the plasmasheet. We review these impacts by examining ultra-relativistic electron dynamics during seemingly different storms during the Van Allen Probe era, including during the Baker et al. third radiation belt, and show the observed behaviour can be largely explained by differences in the time sequence of events described above.

  6. Reanalysis and forecasting killer electrons in Earth's radiation belts using the VERB code

    Science.gov (United States)

    Kellerman, Adam; Kondrashov, Dmitri; Shprits, Yuri; Podladchikova, Tatiana; Drozdov, Alexander

    2016-07-01

    The Van Allen radiation belts are torii-shaped regions of trapped energetic particles, that in recent years, have become a principle focus for satellite operators and engineers. During geomagnetic storms, electrons can be accelerated up to relativistic energies, where they may penetrate spacecraft shielding and damage electrical systems, causing permanent damage or loss of spacecraft. Data-assimilation provides an optimal way to combine observations of the radiation belts with a physics-based model in order to more accurately specify the global state of the Earth's radiation belts. We present recent advances to the data-assimilative version of the Versatile Electron Radiation Belt (VERB) code, including more sophisticated error analysis, and incorporation of realistic field-models to more accurately specify fluxes at a given MLT or along a spacecraft trajectory. The effect of recent stream-interaction-region (SIR) driven enhancements are investigated using the improved model. We also present a real-time forecast model based on the data-assimilative VERB code, and discuss the forecast performance over the past 12 months.

  7. Wave Distribution Functions of Plasmaspheric Hiss and their Effects on Radiation Belt Dynamics

    Science.gov (United States)

    Santolik, O.; Ripoll, J. F.; Kurth, W. S.; Hospodarsky, G. B.; Kletzing, C.

    2015-12-01

    Plasmaspheric hiss is formed by whistler-mode waves which play an important role in the dynamics the Earth's radiation belts, specifically in connection with the slot region between the inner and outer Van Allen belts. The origin of plasmaspheric hiss is still a subject of discussions and these waves are known for their complex propagation properties. They are often far from a single plane wave approximation, forming a continuous distribution of the wave energy density with respect to the wave vector direction (wave distribution function). Analysis of polarization and propagation parameters of these waves provides us with inputs for modeling of radiation belt dynamics. We use the data of the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft, to analyze simultaneous measurements of all electric and magnetic field components, together with measurements of the plasma density based on the determination of the upper hybrid resonance frequency. Using this unique data set we estimate the wave distribution functions of plasmaspheric hiss and we model the effects of these waves on the decay rates of radiation belt electrons through quasilinear pitch angle diffusion.

  8. 78 FR 71546 - Safety Zone; Belt Parkway Bridge Construction, Gerritsen Inlet, Brooklyn, NY

    Science.gov (United States)

    2013-11-29

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Belt Parkway Bridge Construction, Gerritsen... for the safety of life in the regulated area during the construction of the Bridge. DATES: Comments.... SUPPLEMENTARY INFORMATION: Table of Acronyms COTP Captain of the Port DHS Department of Homeland Security...

  9. Prompting Safety Belt Use: Comparative Impact on the Target Behavior and Relevant Body Language

    Science.gov (United States)

    Cox, Matthew G.; Geller, E. Scott

    2010-01-01

    Researchers used two behavioral prompts to compare increases in safety belt use: a Click It or Ticket prompt or a Flash-for-Life prompt. Participants were 1,822 unbuckled drivers exiting two student parking lots of a large university. Research assistants identified unbuckled drivers, flashed one of the two prompts, and recorded whether drivers…

  10. 76 FR 18042 - Uniform Criteria for State Observational Surveys of Seat Belt Use

    Science.gov (United States)

    2011-04-01

    ... selection. A State may draw a simple random sample without stratification from the entire road sampling... Seat Belt Use (the Uniform Criteria). See 63 FR 46389. On March 14, 2000, NHTSA published a Final Rule, adopting the Uniform Criteria with one clarifying change.\\1\\ See 65 FR 13679. \\1\\ In 2000, NHTSA...

  11. Control of the energetic proton flux in the inner radiation belt by artificial means

    Science.gov (United States)

    Shao, X.; Papadopoulos, K.; Sharma, A. S.

    2009-07-01

    Earth's inner radiation belt located inside L = 2 is dominated by a relatively stable flux of trapped protons with energy from a few to over 100 MeV. Radiation effects in spacecraft electronics caused by the inner radiation belt protons are the major cause of performance anomalies and lifetime of Low Earth Orbit satellites. For electronic components with large feature size, of the order of a micron, anomalies occur mainly when crossing the South Atlantic Anomaly. However, current and future commercial electronic systems are incorporating components with submicron size features. Such systems cannot function in the presence of the trapped 30-100 MeV protons, as hardening against such high-energy protons is essentially impractical. The paper discusses the basic physics of the interaction of high-energy protons with low-frequency Shear Alfven Wave (SAW) under conditions prevailing in the radiation belts. Such waves are observed mainly in the outer belt, and it is believed that they are excited by an Alfven Ion Cyclotron instability driven by anisotropic equatorially trapped energetic protons. The paper derives the bounce and drift-averaged diffusion coefficients and uses them to determine the proton lifetime as a function of the spectrum and amplitude of the volume-averaged SAW resonant with the trapped energetic protons. The theory is applied to the outer and inner radiation belts. It is found that the resonant interaction of observed SAW with nT amplitude in the outer belt results in low flux of trapped protons by restricting their lifetime to periods shorter than days. A similar analysis for the inner radiation belt indicates that broadband SAW in the 1-10 Hz frequency range and average amplitude of 25 pT would reduce the trapped energetic proton flux by more than an order of magnitude within 2 to 3 years. In the absence of naturally occurring SAW waves, such reduction can be achieved by injecting such waves from ground-based transmitters. The analysis indicates

  12. Insights on radiation belt physics from the dynamics radiation environment assimilation model, DREAM

    International Nuclear Information System (INIS)

    Complete text of publication follows. The Dynamic Radiation Environment Assimilation Model (DREAM) is a coupled, inner magnetosphere model with modules that include the ring current, the radiation belts, self-consistent global magnetic fields, Kalman filter data assimilation, and customized user applications. DREAM was developed at Los Alamos National Laboratory with the goals of specifying, predicting and understanding the near-Earth space environment. Here we will focus on new understanding of physics of the inner magnetosphere that DREAM has provided and, even more specifically, on the physics of radiation belt acceleration, transport, and loss. One early and important contribution was providing definitive evidence that local acceleration processes acting inside or near geosynchronous orbit are required in order to explain radiation belt dynamics. Another critical process we investigated was loss of radiation belt electrons by radial diffusion or transport to the magnetopause. A critical calculation here is accurate determination of the adiabatic redistribution of particles due to the storm-time ring current (the 'Dst' effect) which can cause both apparent 'loss' of particles at a given satellite. At different times and at different energies, DREAM can determine whether the region outside the trapping boundary acts as a source (the plasma sheet) a sink (the magnetopause) or a combination of both. Another fundamental sink of radiation belt electrons is the atmospheric loss cone where pitch angle scattering can remove electrons trough precipitation. In the final topic for this talk we will describe how we use DREAM to determine the relationship between trapped and precipitating populations and how we relate LEO measurements to high-altitude measurements using observed and modeled characteristics of magnetospheric wave populations.

  13. Study of movement of the western and central belts of Peninsular Malaysia using GPS data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ramli, Siti Hafizah; Samsudin, Abdul Rahim [Geology Programme, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Since the large earthquakes in Sumatera and Nias, there were some tremors incidents at Bukit Tinggi. Therefore, a study on the earth’s crust movement and the effects of the earthquake in Indonesia on the tectonic blocks of Peninsular Malaysia have been carried out using GPS data analysis. GPS data from five MyRTKnet stations within Peninsular Malaysia have been analyzed to monitor the movement of two major tectonic blocks of Peninsular Malaysia which are the western belt represented by the Behrang (BEHR) and UPM Serdang (UPMS) stations and the central belt represented by Bentong (BENT), Jerantut (JRNT) and Temerloh (TLOH) stations. GPS data recorded from 2005 to 2010 were analysed based on horizontal and vertical displacements of the respective stations by using Trimble Business Centre (TBC) software. Based on the results of accumulated displacements of recorded GPS data from January 2006 to December 2013, it shows that the western belt which represented by UPMS has shifted 0.096m towards northwest with changes of ellipsoidal height of +0.030m while the central belt which represented by TLOH has shifted 0.080m towards northwest with changes of ellipsoidal height of −0.015m. Meanwhile, BENT station which is located on the Bentong-Raub suture zone turns to its original position as well as JRNT station. However, BEHR station which are located in western belt do not show any movements. All of these movements may be due to the influence of reactive faults in the stations area stimulated by several large earthquakes that occurred in 2005 to 2010. Study on using the GPS data analysis and combine with integrated geophysical methods are necessary to understand in detail about the tectonic evolution of Peninsular Malaysia.

  14. Study of movement of the western and central belts of Peninsular Malaysia using GPS data analysis

    International Nuclear Information System (INIS)

    Since the large earthquakes in Sumatera and Nias, there were some tremors incidents at Bukit Tinggi. Therefore, a study on the earth’s crust movement and the effects of the earthquake in Indonesia on the tectonic blocks of Peninsular Malaysia have been carried out using GPS data analysis. GPS data from five MyRTKnet stations within Peninsular Malaysia have been analyzed to monitor the movement of two major tectonic blocks of Peninsular Malaysia which are the western belt represented by the Behrang (BEHR) and UPM Serdang (UPMS) stations and the central belt represented by Bentong (BENT), Jerantut (JRNT) and Temerloh (TLOH) stations. GPS data recorded from 2005 to 2010 were analysed based on horizontal and vertical displacements of the respective stations by using Trimble Business Centre (TBC) software. Based on the results of accumulated displacements of recorded GPS data from January 2006 to December 2013, it shows that the western belt which represented by UPMS has shifted 0.096m towards northwest with changes of ellipsoidal height of +0.030m while the central belt which represented by TLOH has shifted 0.080m towards northwest with changes of ellipsoidal height of −0.015m. Meanwhile, BENT station which is located on the Bentong-Raub suture zone turns to its original position as well as JRNT station. However, BEHR station which are located in western belt do not show any movements. All of these movements may be due to the influence of reactive faults in the stations area stimulated by several large earthquakes that occurred in 2005 to 2010. Study on using the GPS data analysis and combine with integrated geophysical methods are necessary to understand in detail about the tectonic evolution of Peninsular Malaysia

  15. EVIDENCE FROM THE ASTEROID BELT FOR A VIOLENT PAST EVOLUTION OF JUPITER'S ORBIT

    International Nuclear Information System (INIS)

    We use the current orbital structure of large (>50 km) asteroids in the main asteroid belt to constrain the evolution of the giant planets when they migrated from their primordial orbits to their current ones. Minton and Malhotra showed that the orbital distribution of large asteroids in the main belt can be reproduced by an exponentially decaying migration of the giant planets on a timescale of τ ∼ 0.5 Myr. However, self-consistent numerical simulations show that the planetesimal-driven migration of the giant planets is inconsistent with an exponential change in their semi-major axes on such a short timescale. In fact, the typical timescale is τ ≥ 5 Myr. When giant planet migration on this timescale is applied to the asteroid belt, the resulting orbital distribution is incompatible with the observed one. However, the planet migration can be significantly sped up by planet-planet encounters. Consider an evolution where both Jupiter and Saturn have close encounters with a Neptune-mass planet (presumably Uranus or Neptune itself) and where this third planet, after being scattered inward by Saturn, is scattered outward by Jupiter. This scenario leads to a very rapid increase in the orbital separation between Jupiter and Saturn which we show here to have only mild effects on the structure of the asteroid belt. This type of evolution is called a 'jumping-Jupiter' case. Our results suggest that the total mass and dynamical excitation of the asteroid belt before migration were comparable to those currently observed. Moreover, they imply that, before migration, the orbits of Jupiter and Saturn were much less eccentric than their current ones.

  16. Steady-state responses of a belt-drive dynamical system under dual excitations

    Science.gov (United States)

    Ding, Hu

    2016-02-01

    The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete-continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and driven pulleys and the accessory pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the firing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Furthermore, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numerical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the driven pulley and the accessory pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foundation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.

  17. Is the Grand Tack model compatible with the orbital distribution of main belt asteroids?

    Science.gov (United States)

    Deienno, Rogerio; Gomes, Rodney S.; Walsh, Kevin J.; Morbidelli, Alessandro; Nesvorný, David

    2016-07-01

    The Asteroid Belt is characterized by the radial mixing of bodies with different physical properties, a very low mass compared to Minimum Mass Solar Nebula expectations and has an excited orbital distribution, with eccentricities and inclinations covering the entire range of values allowed by the constraints of dynamical stability. Models of the evolution of the Asteroid Belt show that the origin of its structure is strongly linked to the process of terrestrial planet formation. The Grand Tack model presents a possible solution to the conundrum of reconciling the small mass of Mars with the properties of the Asteroid Belt, including the mass depletion, radial mixing and orbital excitation. However, while the inclination distribution produced in the Grand Tack model is in good agreement with the one observed, the eccentricity distribution is skewed towards values larger than those found today. Here, we evaluate the evolution of the orbital properties of the Asteroid Belt from the end of the Grand Tack model (at the end of the gas nebula phase when planets emerge from the dispersing gas disk), throughout the subsequent evolution of the Solar System including an instability of the Giant Planets approximately 400 Myr later. Before the instability, the terrestrial planets were modeled on dynamically cold orbits with Jupiter and Saturn locked in a 3:2 mean motion resonance. The model continues for an additional 4.1 Gyr after the giant planet instability. Our results show that the eccentricity distribution obtained in the Grand Tack model evolves towards one very similar to that currently observed, and the semimajor axis distribution does the same. The inclination distribution remains nearly unchanged with a slight preference for depletion at low inclination; this leads to the conclusion that the inclination distribution at the end of the Grand Tack is a bit over-excited. Also, we constrain the primordial eccentricities of Jupiter and Saturn, which have a major influence

  18. Mechanisms of the outer radiation belt electron flux variation during magnetic storms

    Science.gov (United States)

    Nakamura, M.; Obara, T.; Koshiishi, H.; Koga, K.; Matsumoto, H.; Goka, T.

    2003-12-01

    We have investigated variations of the energetic electron flux (> 0.4 MeV) and the magnetic field in the outer radiation belt obtained from the Standard DOse Monitor (SDOM) and the MAgnetoMeter (MAM) of the Space Environment Data Acquisition equipment (SEDA) onboard Tsubasa (Mission Demonstration Test Satellite (MDS)-1). Since Tsubasa operates in geostationary transfer orbit (GTO) with an orbital period of 10 hours and an inclination of 28.5 degrees, it has provided a rare opportunity for directly observing near-equatorial radiation belt plasma particles and the magnetic field during magnetic storms. The decreases of the energetic electron flux during the main phase of the magnetic storms, and the subsequent recoveries and enhancements during the recovery phase in the outer radiation belt are linked respectively to typical variations of the magnetic field. At the moment that the outer radiation belt flux sharply drops during the main phase of the 17 April 2002 magnetic storm, the butterfly distribution is observed at L=5 and the magnetic equator where the magnitude of magnetic field is much smaller than the IGRF model. Calculating the drift motions of the energetic electrons in the Tyganenko 2001 magnetospheric magnetic field model, shows that the drift-shell splitting mechanism could generate the butterfly distribution due to loss of the near-equatorially mirroring electrons through dayside magnetopause boundary. We evaluate roles and contributions of the other possible mechanisms to explain the flux decreases. We discuss the three-dimensional field configuration in the magnetopause to compare with the low earth orbital observation of the outer radiation belt flux.

  19. New Findings in High-Pressure and Ultrahigh-Pressure Metamorphic Belt of Tongbaishan-Dabieshan Regions, Central China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Tongbai-Dabieshan high-pressure (HP) and ultrahigh-pressure (UHP) belt is sandwiched between the Yangtze and the Sinokorean cratons. It connects the Qinling orogenic belt in the west and links toward the east to the Sulu ultrahigh-pressure (UHP) belt. At present there is a consensus that the UHP metamorphic rocks are the products of the oblique collision between the Yangtze and Sinokorean cratons during the Triassic. However, there is still a lot of controversies about the formation and exhumation of the HP- and UHP-metamorphic belts. The present research work on the composition and the structural geometry and kinetics of the HP- and UHP- metamorphic belt has shown the following new results: (1) The overall structural geometry pattern of Dabieshan is similar to the metamorphic core complex developed in the western North America; (2) The discoveries of HP and UHP metamorphic rocks in the north of Dabieshan indicate that the significance of Shuihou-Wuhe fault should be re-evaluated; (3) A series of micro-structural evidence, including the newly-found retrograde granulite facies assemblages in the garnet pyroxenites, substantiate the extensional processes following the collision event; (4) The discovery of partial melting phenomena in the UHP-metamorphic belts illuminates the relationship between the HP- and UHP metamorphic rocks and their associated granite gneiss. All of these new findings will greatly improve our understanding of the formation and exhumation of the high-pressure and ultrahigh pressure metamorphic belts.

  20. Pelvic belt effects on pelvic morphometry, muscle activity and body balance in patients with sacroiliac joint dysfunction.

    Directory of Open Access Journals (Sweden)

    Odette Soisson

    Full Text Available The sacroiliac joint (SIJ is frequently involved in low back and pelvic girdle pain. However, morphometrical and functional characteristics related to SIJ pain are poorly defined. Pelvic belts represent one treatment option, but evidence still lacks as to their pain-reducing effects and the mechanisms involved. Addressing these two issues, this case-controlled study compares morphometric, functional and clinical data in SIJ patients and healthy controls and evaluates the effects of short-term pelvic belt application.Morphometric and functional data pertaining to pelvic belt effects were compared in 17 SIJ patients and 17 controls. Lumbar spine and pelvis morphometries were obtained from 3T magnetic resonance imaging. Functional electromyography data of pelvis and leg muscles and center of pressure excursions were measured in one-leg stance. The numerical rating scale was used to evaluate immediate pain-reducing effects.Pelvic morphometry was largely unaltered in SIJ patients and also by pelvic belt application. The angle of lumbar lateral flexion was significantly larger in SIJ patients without belt application. Muscle activity and center of pressure were unaffected by SIJ pain or by belt application in one-leg stance. Nine of 17 patients reported decreased pain intensities under moderate belt application, four reported no change and four reported increased pain intensity. For the entire population investigated here, this qualitative description was not confirmed on a statistical significant level.Minute changes were observed in the alignment of the lumbar spine in the frontal plane in SIJ patients. The potential pain-decreasing effects of pelvic belts could not be attributed to altered muscle activity, pelvic morphometry or body balance in a static short-term application. Long-term belt effects will therefore be of prospective interest.