WorldWideScience

Sample records for temperature burial stress

  1. Rock stresses associated with burial of nuclear waste

    International Nuclear Information System (INIS)

    Voight, B.

    1977-01-01

    Rock stress changes related to long-term deep storage of nuclear waste involve thermoelastic and pore fluid pressure changes associated with excavation and heating. Computer models are being examined to assess the question of thermally-induced fracturing in storage rock surrounding radioactive waste containers. Stresses are evaluated in three dimensions, employing elastic-plastic finite element codes. Potential failure conditions are expressed in terms of ''effective stresses,'' and force and thermal fields are incremented to produce an appropriate load path. In general, heating in vicinity of waste containers produces a zone of high compression bonded by a zone of circumferential and axial tension. (At this conference an analogous case of thermal stresses was documented and illustrated for larger-scale temperature domains associated with geothermal areas in Iceland.) Fractures are possible in radial directions as well as perpendicular to the axis of the cylindrical heat source. In addition, the mechanical effect of a vapor pulse will be explored by a two-phase numerical fluid transport model used in conjunction with mechanical finite element models. This portion of the work, being conducted jointly with C. R. Faust and J. W. Mercer of the US Geological Survey, should provide a preliminary appreciation of the possible effect of phase changes on fracturing of burial sites. Preliminary work suggests the possibility of establishing design criteria (e.g., design burial depth, depth of canister below storage vault) in order to minimize problems of potential rock fracture

  2. Burial stress and elastic strain of carbonate rocks

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2014-01-01

    strain multiplied by the rock frame modulus. We cannot measure the strain directly in the subsurface, but from the data on bulk density and P‐wave velocity, we can estimate the rock frame modulus and Biot's coefficient and then calculate the “effective vertical stress” as the total vertical stress minus......Burial stress on a sediment or sedimentary rock is relevant for predicting compaction or failure caused by changes in, e.g., pore pressure in the subsurface. For this purpose, the stress is conventionally expressed in terms of its effect: “the effective stress” defined as the consequent elastic...... the product of pore pressure and Biot's coefficient. We can now calculate the elastic strain by dividing “effective stress” with the rock frame modulus. By this procedure, the degree of elastic deformation at a given time and depth can be directly expressed. This facilitates the discussion of the deformation...

  3. The Influence of Organic Material and Temperature on the Burial Tolerance of the Blue Mussel, Mytilus edulis: Considerations for the Management of Marine Aggregate Dredging.

    Directory of Open Access Journals (Sweden)

    Richard S Cottrell

    Full Text Available Aggregate dredging is a growing source of anthropogenic disturbance in coastal UK waters and has the potential to impact marine systems through the smothering of benthic fauna with organically loaded screening discards. This study investigates the tolerance of the blue mussel, Mytilus edulis to such episodic smothering events using a multi-factorial design, including organic matter concentration, temperature, sediment fraction size and duration of burial as important predictor variables.Mussel mortality was significantly higher in organically loaded burials when compared to control sediments after just 2 days. Particularly, M. edulis specimens under burial in fine sediment with high (1% concentrations of organic matter experienced a significantly higher mortality rate (p<0.01 than those under coarse control aggregates. Additionally, mussels exposed to the summer maximum temperature treatment (20°C exhibited significantly increased mortality (p<0.01 compared to those in the ambient treatment group (15°C. Total Oxygen Uptake rates of experimental aggregates were greatest (112.7 mmol m-2 day-1 with 1% organic loadings in coarse sediment at 20°C. Elevated oxygen flux rates in porous coarse sediments are likely to be a function of increased vertical migration of anaerobically liberated sulphides to the sediment-water interface. However, survival of M. edulis under bacterial mats of Beggiatoa spp. indicates the species' resilience to sulphides and so we propose that the presence of reactive organic matter within the burial medium may facilitate bacterial growth and increase mortality through pathogenic infection. This may be exacerbated under the stable interstitial conditions in fine sediment and increased bacterial metabolism under high temperatures. Furthermore, increased temperature may impose metabolic demands upon the mussel that cannot be met during burial-induced anaerobiosis.Lack of consideration for the role of organic matter and

  4. Temperature distribution and thermal stress

    Indian Academy of Sciences (India)

    Abstract. Thermal effects of a double-end-pumped cubic Nd:YVO4 laser crystal are investigated in this paper. A detailed analysis of temperature distribution and thermal stress in cubic crystal with circular shape pumping is discussed. It has been shown that by considering the total input powers as constant, the ...

  5. Reconstruction of burial history, temperature, source rock maturity and hydrocarbon generation in the northwestern Dutch offshore

    OpenAIRE

    Abdul Fattah, R.; Verweij, J.M.; Witmans, N.; Veen, J.H. ten

    2012-01-01

    3D basin modelling is used to investigate the history of maturation and hydrocarbon generation on the main platforms in the northwestern part of the offshore area of the Netherlands. The study area covers the Cleaverbank and Elbow Spit Platforms. Recently compiled maps and data are used to build the input geological model. An updated and refined palaeo water depth curve and newly refined sediment water interface temperatures (SWIT) are used in the simulation. Basal heat flow is calculated usi...

  6. Interactive effects of mechanical stress, sand burial and defoliation on growth and mechanical properties in Cynanchum komarovii

    NARCIS (Netherlands)

    Xu, L.; Yu, F.H.; Werger, M.; Dong, M.; Anten, N.P.R.

    2013-01-01

    In drylands, wind, sand burial and grazing are three important factors affecting growth and mechanical properties of plants, but their interactive effects have not yet been investigated. Plants of the semi-shrub Cynanchum komarovii, common in semi-arid parts of NE Asia, were subjected to brushing,

  7. Buried Alive: The Behavioural Response of the Mussels, Modiolus modiolus and Mytilus edulis to Sudden Burial by Sediment.

    Directory of Open Access Journals (Sweden)

    Zoë L Hutchison

    Full Text Available Sedimentation in the sea occurs through natural processes, such as wave and tidal action, which can be exacerbated during storms and floods. Changes in terrestrial land use, marine aggregate extraction, dredging, drilling and mining are known to result in substantial sediment deposition. Research suggests that deposition will also occur due to the modern development of marine renewable energy. The response to individual burial under three depths of sediment, three sediment fractions and five burial durations was investigated in two mussel species, Modiolus modiolus and Mytilus edulis in specialist mesocosms. Both mussel species showed substantial mortality, which increased with duration of burial and burial by finer sediment fractions. M. modiolus was better able to survive short periods of burial than M. edulis, but at longer durations mortality was more pronounced. No mortality was observed in M. modiolus in burial durations of eight days or less but by 16 days of burial, over 50% cumulative mortality occurred. Under variable temperature regimes, M. edulis mortality increased from 20% at 8°C to over 60% at 14.5 and 20°C. Only M. edulis was able to emerge from burial, facilitated by increased byssus production, laid mostly on vertical surfaces but also on sediment particles. Emergence was higher from coarse sediment and shallow burials. Byssus production in M. edulis was not related to the condition index of the mussels. Results suggest that even marginal burial would result in mortality and be more pronounced in warm summer periods. Our results suggest that in the event of burial, adult M. modiolus would not be able to emerge from burial unless local hydrodynamics assist, whereas a small proportion of M. edulis may regain contact with the sediment water interface. The physiological stress resulting in mortality, contribution of local hydrodynamics to survival and other ecological pressures such as mussels existing in aggregations, are

  8. The effects of temperature on the burial performance and axial motor pattern of the sand-swimming of the Mojave fringe-toed lizard Uma scoparia.

    Science.gov (United States)

    Jayne, B C; Daggy, M W

    2000-04-01

    Although lateral axial bending is widespread for the locomotion of ectothermic vertebrates, the axial motor patterns of terrestrial taxa are known only for a limited number of species and behaviors. Furthermore, the extent to which the trunk and tail of ectothermic tetrapods have similar motor patterns is poorly documented. We therefore recorded the activity of the epaxial muscles in the trunk and tail of sand-swimming Mojave fringe-toed lizards (Uma scoparia) to determine whether this specialized behavior has features of the motor pattern that differ from those of diverse ectothermic vertebrates. Muscle activity during initial sand-swimming was a standing-wave pattern in the trunk and tail. Next, the hind limbs moved alternately and the caudofemoralis muscles and nearby axial muscle in the trunk and tail had similar long-duration electromyographic bursts, whereas the anterior trunk had shorter, more frequent electromyographic bursts. The final tail burial involved a traveling wave of posteriorly propagated axial muscle activity within localized regions of the tail. With increased temperature (from 22 to 40 degrees C), the mean frequencies of axial oscillations increased from approximately 7 to 21 Hz, and the greatest value (33 Hz) was nearly twice the maximal limb cycling frequency during running. The mean burial time at the lowest temperature (3.8 s) was nearly twice that for a 10 degrees C higher temperature. For the axial electromyograms, a decrease in temperature of 18 degrees C more than doubled the electromyographic and cycle durations, whereas the duty factors and intersegmental phase lags changed only slightly with temperature.

  9. Thermal maturity and burial history modelling of shale is enhanced by use of Arrhenius time-temperature index and memetic optimizer

    Directory of Open Access Journals (Sweden)

    David A. Wood

    2018-03-01

    Full Text Available Thermal maturity indices and modelling based on Arrhenius-equation reaction kinetics have played an important role in oil and gas exploration and provided petroleum generation insight for many kerogen-rich source rocks. Debate continues concerning how best to integrate the Arrhenius equation and which activation energies (E and frequency factors (A values to apply. A case is made for the strong theoretical basis and practical advantages of the time-temperature index (∑TTIARR method, first published in 1998, using a single, carefully selected E-A set (E = 218 kJ/mol (52.1 kcal/mol; A = 5.45E+26/my from the well-established A-E trend for published kerogen kinetics. An updated correlation between ∑TTIARR and vitrinite reflectance (Ro is provided in which the ∑TTIARR scale spans some 18 orders of magnitude. The method is readily calculated in spreadsheets and can be further enhanced by visual basic for application code to provide optimization. Optimization is useful for identifying possible geothermal gradients and erosion intervals covering multiple burial intervals that can match calculated thermal maturities with measured Ro data. A memetic optimizer with firefly and dynamic local search memes is described that flexibly conducts exploration and exploitation of the feasible, multi-dimensional, thermal history solution space to find high-performing solutions to complex burial and thermal histories. A complex deep burial history example, with several periods of uplift and erosion and fluctuating heat flow is used to demonstrate what can be achieved with the memetic optimizer. By carefully layering in constraints to the models specific insights to episodes in their thermal history can be exposed, leading to better characterization of the timing of petroleum generation. The objective function found to be most effective for this type of optimization is the mean square error (MSE of multiple burial intervals for the difference between

  10. Constitutive relationships for ocean sediments subjected to stress and temperature gradients

    International Nuclear Information System (INIS)

    Davies, T.G.; Banerjee, P.K.

    1980-08-01

    The disposal of low-level nuclear wastes by burial in deep sea sediments is an option currently being considered. This report lays the groundwork for an investigation of the stability of canisters containing nuclear wastes against movement due to fluidisation of the surrounding sediments, where such fluidisation may result from thermally induced stresses. The requisite constitutive relationships for ocean sediments under stress and temperature gradients are derived from the theory of critical state soil mechanics. A parametric survey has been made of the behaviour of an element of soil in order to assess various models and the importance of the governing parameters, The formulation of a finite element algorithm is given for the solution of the sediment stability problem. (author)

  11. A long burial for radioactive wastes

    International Nuclear Information System (INIS)

    Takibaev, Zh.S.

    1998-01-01

    Several ways of radioactive wastes (RAW) burial are considered and characterized: - burial in geological formation deeply under ground; - dispatch RAW to cosmos; - transmutation of highly active and long-living radionuclides into short-living ones by means of nuclear transformation during irradiation of RAW with protons or neutrons; - burial RAW in mountains isolated from environment. Especial attention to RAW self-burial method on depth not less 1 km in Earth crust is paid. Self-burial (i. e. moving of whole RAW object down) is possible when temperature of object is above 1000 deg C and density ρ p is larger than density of surrounding it earth rock ρ r . Two methods of for maintaining of high temperature (>1000-1500 deg C) during quate large period (few hundreds years) are proposed : 1) Creation high temperature by means of residual energy emission by itself of RAW object. 2) Adaptation of reactor assembly ensuring high temperature during prolonged period (more hundred years) to RAW object

  12. Porosity and sonic velocity depth trends of Eocene chalk in Atlantic Ocean: Influence of effective stress and temperature

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Fabricius, Ida Lykke

    2014-01-01

    data were correlated to vertical effective stresses and to TTI.Our porosity data showed a broader porosity trend in the mechanical compaction zone, and the onset of the formation of limestone at a shallower burial depth than the porosity data of the Ontong Java Plateau chalk show. Our porosity data do...... of geological age on chalk compaction trends. For each depth, vertical effective stresses as defined by Terzaghi and by Biot were calculated. We used bottom-hole temperature data to calculate the time–temperature index of thermal maturity (TTI) as defined by Lopatin. Porosity and compressional wave velocity...... not show or at least it is difficult to define a clear pore-stiffening contact cementation trend as the Ontong Java Plateau chalk. Mechanical compaction is the principal cause of porosity reduction (at shallow depths) in the studied Eocene chalk, at least down to about 5MPa Terzaghi׳s effective stress...

  13. 78 FR 76574 - Burial Benefits

    Science.gov (United States)

    2013-12-18

    ..., Congress' clear motivation was to make burial benefits ``easier to administer, i.e., through existing VA...), the Government may pay up to $800 for the funeral and burial expenses of an employee who dies in...

  14. Shallow land burial handbook

    International Nuclear Information System (INIS)

    Stinton, L.H.

    1983-01-01

    The facility development phases (preliminary analysis, site selection, facility design and construction, facility operation, and facility closure/post-closure) are systematically integrated into a logical plan for developing near surface disposal plans. The Shallow Land Burial Handbook provides initial guidance and concepts for understanding the magnitude and the complexity of developing new low-level radioactive waste disposal facilities

  15. Flexible MOFs under stress: pressure and temperature.

    Science.gov (United States)

    Clearfield, Abraham

    2016-03-14

    In the recent past an enormous number of Metal-Organic Framework type compounds (MOFs) have been synthesized. The novelty resides in their extremely high surface area and the ability to include additional features to their structure either during synthesis or as additives to the MOF. This versatility allows for MOFs to be designed for specific applications. However, the question arises as to whether a particular MOF can withstand the stress that may be encountered in fulfillment of the designated application. In this study we describe the behavior of two flexible MOFs under pressure and several others under temperature increase. The pressure study includes both experimental and theoretical calculations. In the thermal processes evidence for colossal negative thermal expansion were encountered.

  16. Eye surface temperature detects stress response in budgerigars (Melopsittacus undulatus).

    Science.gov (United States)

    Ikkatai, Yuko; Watanabe, Shigeru

    2015-08-05

    Previous studies have suggested that stressors not only increase body core temperature but also body surface temperature in many animals. However, it remains unclear whether surface temperature could be used as an alternative to directly measure body core temperature, particularly in birds. We investigated whether surface temperature is perceived as a stress response in budgerigars. Budgerigars have been used as popular animal models to investigate various neural mechanisms such as visual perception, vocal learning, and imitation. Developing a new technique to understand the basic physiological mechanism would help neuroscience researchers. First, we found that cloacal temperature correlated with eye surface temperature. Second, eye surface temperature increased after handling stress. Our findings suggest that eye surface temperature is closely related to cloacal temperature and that the stress response can be measured by eye surface temperature in budgerigars.

  17. Burial Ground Expansion Hydrogeologic Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Gaughan , T.F.

    1999-02-26

    Sirrine Environmental Consultants provided technical oversight of the installation of eighteen groundwater monitoring wells and six exploratory borings around the location of the Burial Ground Expansion.

  18. Alternatives to shallow land burial

    International Nuclear Information System (INIS)

    Burton, B.W.

    1982-01-01

    During FY79 and FY80 the Los Alamos National Laboratory and its contractors performed a preliminary assessment of several alternatives to shallow land burial of low-level waste, including deeper burial, mined cavities, specially engineered storage buildings, well injection of liquid waste, and seabed disposal. Only deeper burial and mined cavities seem acceptable as near-term alternatives. A waste management program using a combination of disposal alternatives is recommended. Research needed to implement the deeper burial and mined cavity options is identified

  19. Modelling and analysis of radial thermal stresses and temperature ...

    African Journals Online (AJOL)

    A theoretical investigation has been undertaken to study operating temperatures, heat fluxes and radial thermal stresses in the valves of a modern diesel engine with and without air-cavity. Temperatures, heat fluxes and radial thermal stresses were measured theoretically for both cases under all four thermal loading ...

  20. Temperature stress and plant sexual reproduction: uncovering the weakest links

    OpenAIRE

    Zinn, Kelly E.; Tunc-Ozdemir, Meral; Harper, Jeffrey F.

    2010-01-01

    The reproductive (gametophytic) phase in flowering plants is often highly sensitive to hot or cold temperature stresses, with even a single hot day or cold night sometimes being fatal to reproductive success. This review describes studies of temperature stress on several crop plants, which suggest that pollen development and fertilization may often be the most sensitive reproductive stage. Transcriptome and proteomic studies on several plant species are beginning to identify stress response p...

  1. The stress relaxation of cement clinkers under high temperature

    Science.gov (United States)

    Wang, Xiufang; Bao, Yiwang; Liu, Xiaogen; Qiu, Yan

    2015-12-01

    The energy consumption of crushing is directly affected by the mechanical properties of cement materials. This research provides a theoretical proof for the mechanism of the stress relaxation of cement clinkers under high temperature. Compression stress relaxation under various high temperatures is discussed using a specially developed load cell, which can measure stress and displacement under high temperatures inside an autoclave. The cell shows that stress relaxation dramatically increases and that the remaining stress rapidly decreases with an increase in temperature. Mechanical experiments are conducted under various temperatures during the cooling process to study the changes in the grinding resistance of the cement clinker with temperature. The effects of high temperature on the load-displacement curve, compressive strength, and elastic modulus of cement clinkers are systematically studied. Results show that the hardening phenomenon of the clinker becomes apparent with a decrease in temperature and that post-peak behaviors manifest characteristics of the transformation from plasticity to brittleness. The elastic modulus and compressive strength of cement clinkers increase with a decrease in temperature. The elastic modulus increases greatly when the temperature is lower than 1000 °C. The compressive strength of clinkers increases by 73.4% when the temperature drops from 1100 to 800 °C.

  2. Arbuscular mycorrhizal fungi and tolerance of temperature stress in plants

    DEFF Research Database (Denmark)

    Zhu, Xiancan; Song, Fengbin; Liu, Fulai

    2017-01-01

    to improve tolerance to temperature stress in plants. This chapter addresses the effect of AM symbiosis on plant growth and biomass production, water relations (water potential, stomatal conductance, and aquaporins), photosynthesis (photosynthetic rate, chlorophyll, and chlorophyll fluorescence), plasma...... membrane permeability (malondialdehyde and ATPase), reactive oxygen species (ROS) and antioxidants, osmotic adjustment, carbohydrate metabolism, nutrient acquisition, and secondary metabolism under low or high temperature stress. The possible mechanisms of AM symbiosis improving temperature stress......Temperature is one of the most important environmental factors that determine the growth and productivity of plants across the globe. Many physiological and biochemical processes and functions are affected by low and high temperature stresses. Arbuscular mycorrhizal (AM) symbiosis has been shown...

  3. Association between temperature and maternal stress during pregnancy.

    Science.gov (United States)

    Lin, Yanfen; Hu, Wenjing; Xu, Jian; Luo, Zhongcheng; Ye, Xiaofang; Yan, Chonghuai; Liu, Zhiwei; Tong, Shilu

    2017-10-01

    Maternal psychological stress during pregnancy has essentially been conceptualized as a teratogen. However, little is known about the effect of temperature on maternal stress during pregnancy. The aim of this study is to investigate the relationship between temperature and maternal stress during pregnancy. In 2010, a total of 1931 eligible pregnant women were enrolled across Shanghai from four prenatal-care clinics during their mid-to-late pregnancy. Maternal life-event stress and emotional stress levels during pregnancy were assessed by the "Life Event Scale for Pregnant Women" (LESPW) and "Symptom Checklist-90-Revised Scale" (SCL-90-R), respectively. Exposure to ambient temperature was evaluated based on daily regional average in different moving average and lag days. The generalized estimating equations were used to evaluate the relationship between daily average temperature/temperature difference and maternal stress. After adjusting for relevant confounders, an U-shaped relationship was observed between daily average temperature and maternal Global-Severity-Index (GSI) of the SCL-90-R. Cumulative exposures to extremely low temperatures (pregnancy. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Beads from Inhumation Rite Burials of Gnezdovo Burial Mound

    Directory of Open Access Journals (Sweden)

    Dobrova Olga P.

    2017-12-01

    Full Text Available The beads from 33 inhumation burials at Gnezdovo burial mound are examined in the article. The beads (total 367 were crafted from stretched tube (258, stretched stick (3, winding (45, press molding (2 pcs., welding (2 pcs., and mosaic beads (9 pcs.. The burial mound contains virtually no broken beads, including the settlement's most common yellow glass beads. Besides glass beads, cornelian, crystal, amber and faience beads have been registered among the burial mound material, as well as beads crafted with metal. Apart from beads, grave inventories contained a series of pendants with a bead strung on a wire ring. The considered complexes contain five pendants of this type. Besides Gnezdovo, similar pendants have been discovered in Kiev, Timerev, Pskov and Vladimir barrows. A comparison between bead sets from Gnezdovo and Kiev burial mounds allows to conclude that the general composition and occurrence frequency of beads is identical for these burials. At the same time, beads crafted with rock crystal, cornelian and metal are more frequently discovered in Kiev inhumations.

  5. Textiles from Scythian burial complexes

    OpenAIRE

    Elena Fialko; Yurii Boltryk

    2013-01-01

    In Northern Black Sea steppes were excavated more than three thousand Scythian burial mounds. In the studied burials were discovered large quantities of artifacts, but leather and textile items are preserved only in a few cases. Some ideas about Scythian costume are found in the works of Greek authors. In this regard, extremely important is the funerary complex dated with the 4th century BC, discovered in barrow Vishnevaja Moghila (Zaporizhia region, Ukraine). In the crypt, which remained und...

  6. Temperature Based Stress Analysis of Notched Members

    Science.gov (United States)

    1979-03-01

    are 1 2 as follows: x-ray microbeam , chemical etching, 3. 4 microhardness, image-distortion, transmission electron 5 6 microscopy, holographic...Materials, 1973, pp. 271-284. 53. Rowland, E. S., "Effect of Residual Stress on Fatigue," Proceedings, Tenth Sagamore Conference , Syracuse University...J. R., "Plastic Yielding at a Crack Tip," Proceedings of the First International Conference on Fracture, Sendal, Japan, Vol. 1, September 1965, pp

  7. How plants cope with temperature stress

    Directory of Open Access Journals (Sweden)

    Walbot Virginia

    2011-11-01

    Full Text Available Abstract A cold night can follow a hot day, and because they cannot move, plants subjected to such temperature fluctuations must acclimate on the basis mainly of pre-existing proteins. Zhang et al. report in a paper in BMC Plant Biology, however, that heat-induced cell death results from transcriptional activation of a kinase related to disease resistance factors and leading to a localized hypersensitive response. This specialized response reflects the failure of adaptations that normally enable plants to survive over a remarkable temperature range, by mechanisms that are not fully understood.

  8. Physiological and biochemical responses to low temperature stress ...

    African Journals Online (AJOL)

    Cuttings of three hybrid clones of P. ussuriensis × P. deltoides were exposed to different low temperatures (cold and freezing) for 24 h, or consecutive low temperatures (5°C, 0 to 120 h), to determine physiological and biochemical responses to cold stress in these woody plants. Soluble sugar and protein contents increased ...

  9. Temperature rise and stress induced by microcracks in accelerating structures

    Directory of Open Access Journals (Sweden)

    W. Zhu

    2010-12-01

    Full Text Available The temperature rise and induced stress due to Ohmic heating in the vicinity of microcracks on the walls of high-gradient accelerating structures are considered. The temperature rise and induced stress depend on the orientation of the crack with respect to the rf magnetic field, the shape of the crack, and the power and duration of the rf pulse. Under certain conditions the presence of cracks can double the temperature rise over that of a smooth surface. Stress at the bottom of the cracks can be several times larger than that of the case when there are no cracks. We study these effects both analytically and by computer simulation. It is shown that the stress in cracks is maximal when the crack depth is on the order of the thermal penetration depth.

  10. Water Stress Detection using Temperature, Emissivity, and Reflectance

    Science.gov (United States)

    Gerhards, Max; Rock, Gilles; Schlerf, Martin; Udelhoven, Thomas

    2017-04-01

    Water stress is one of the most critical abiotic stressors limiting crop development. The main imaging and non-imaging remote sensing based techniques for the detection of plant stress (water stress and other types of stress) are thermography, visible (VIS), near- and shortwave infrared (NIR/SWIR) reflectance, and fluorescence. Just very recently, in addition to broadband thermography, narrowband (hyperspectral) thermal imaging has become available, which even facilitates the retrieval of spectral emissivity as an additional measure of plant stress. It is, however, still unclear at what stage plant stress is detectable with the various techniques. During summer 2014 a water treatment experiment was run on 60 potato plants (Solanum tuberosum L. Cilena) with one half of the plants watered and the other half stressed. Crop response was measured using broadband and hyperspectral thermal cameras and a VNIR/SWIR spectrometer. Stomatal conductance was measured using a leaf porometer. Various measures and indices were computed and analysed for their sensitivity towards water stress (Crop Water Stress Index (CWSI), Moisture Stress Index (MSI), Photochemical Reflectance Index (PRI), and spectral emissivity, amongst others). The results show that water stress as measured through stomatal conductance started on day 2 after watering was stopped. The fastest reacting, i.e., starting on day 7, indices were temperature based measures (e.g., CWSI) and NIR/SWIR reflectance based indices related to plant water content (e.g., MSI). Spectral emissivity reacted equally fast. Contrarily, visual indices (e.g., PRI) either did not respond at all or responded in an inconsistent manner. This experiment shows that pre-visual water stress detection is feasible using indices depicting leaf temperature, leaf water content and spectral emissivity.

  11. Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations

    International Nuclear Information System (INIS)

    Yang, Xu-Sheng; Wang, Yun-Jiang; Wang, Guo-Yong; Zhai, Hui-Ru; Dai, L.H.; Zhang, Tong-Yi

    2016-01-01

    In the present work, stress relaxation tests, high-resolution transmission electron microscopy (HRTEM), and molecular dynamics (MD) simulations were conducted on coarse-grained (cg), nanograined (ng), and nanotwinned (nt) copper at temperatures of 22 °C (RT), 30 °C, 40 °C, 50 °C, and 75 °C. The comprehensive investigations provide sufficient information for the building-up of a formula to describe the time, stress, and temperature-dependent deformation and clarify the relationship among the strain rate sensitivity parameter, stress exponent, and activation volume. The typically experimental curves of logarithmic plastic strain rate versus stress exhibited a three staged relaxation process from a linear high stress relaxation region to a subsequent nonlinear stress relaxation region and finally to a linear low stress relaxation region, which only showed-up at the test temperatures higher than 22 °C, 22 °C, and 30 °C, respectively, in the tested cg-, ng-, and nt-Cu specimens. The values of stress exponent, stress-independent activation energy, and activation volume were determined from the experimental data in the two linear regions. The determined activation parameters, HRTEM images, and MD simulations consistently suggest that dislocation-mediated plastic deformation is predominant in all tested cg-, ng-, and nt-Cu specimens in the initial linear high stress relaxation region at the five relaxation temperatures, whereas in the linear low stress relaxation region, the grain boundary (GB) diffusion-associated deformation is dominant in the ng- and cg-Cu specimens, while twin boundary (TB) migration, i.e., twinning and detwinning with parallel partial dislocations, governs the time, stress, and temperature-dependent deformation in the nt-Cu specimens.

  12. The materiality of Funnelbeaker burial practice : Evidence from the microscope

    NARCIS (Netherlands)

    Gijn, van, A.L.; Marreiros J, Bicho N, Gibaja, J.F.

    2014-01-01

    Flint and amber artefacts from Dutch Funnelbeaker (3400-2900 cal BC) megaliths were examined from a biographical perspective, also involving microwear analysis. It is shown that both flint and amber contributed to the materiality of Funnelbeaker burial practices, which above all stressed the

  13. The Bahrain Burial Mound Project

    DEFF Research Database (Denmark)

    Laursen, Steffen; Johansen, Kasper Lambert

    2007-01-01

    the majority of burial mounds have been removed to make way for roads and housing, and in this process about 8000 mounds have been excavated; of these only c. 265 have been published. In 2006 the Bahrain Directorate for Culture & National Heritage and Moesgaard Museum decided on a collaborative project...... focussed on the Bahrain burial mounds. Within the framework of the Burial Mound Project aerial photos from 1959 have been orto-rectified and geo-referenced and so far a GIS-based digital map representing more than 60.000 mounds have been completed. With respect to the thousands of excavated mounds the huge...... process of linking relevant information to the mounds have been initiated in the course of which excavation data of individual monument is being fed into a relational database. Our preliminary study of the digital maps of the mound cemeteries has revealed an abundance of interesting patterns...

  14. The effect of stress on core and peripheral body temperature in humans.

    Science.gov (United States)

    Vinkers, Christiaan H; Penning, Renske; Hellhammer, Juliane; Verster, Joris C; Klaessens, John H G M; Olivier, Berend; Kalkman, Cor J

    2013-09-01

    Even though there are indications that stress influences body temperature in humans, no study has systematically investigated the effects of stress on core and peripheral body temperature. The present study therefore aimed to investigate the effects of acute psychosocial stress on body temperature using different readout measurements. In two independent studies, male and female participants were exposed to a standardized laboratory stress task (the Trier Social Stress Test, TSST) or a non-stressful control task. Core temperature (intestinal and temporal artery) and peripheral temperature (facial and body skin temperature) were measured. Compared to the control condition, stress exposure decreased intestinal temperature but did not affect temporal artery temperature. Stress exposure resulted in changes in skin temperature that followed a gradient-like pattern, with decreases at distal skin locations such as the fingertip and finger base and unchanged skin temperature at proximal regions such as the infra-clavicular area. Stress-induced effects on facial temperature displayed a sex-specific pattern, with decreased nasal skin temperature in females and increased cheek temperature in males. In conclusion, the amplitude and direction of stress-induced temperature changes depend on the site of temperature measurement in humans. This precludes a direct translation of the preclinical stress-induced hyperthermia paradigm, in which core temperature uniformly rises in response to stress to the human situation. Nevertheless, the effects of stress result in consistent temperature changes. Therefore, the present study supports the inclusion of body temperature as a physiological readout parameter of stress in future studies.

  15. Non-uniform temperature gradients and thermal stresses produced ...

    Indian Academy of Sciences (India)

    Abstract. This work presents numerical analyses of transient temperature and thermally-induced stress distributions in a hollow steel sphere heated by a moving uniform heat source applied on a certain zenithal segment (the heated zenithal segment, H ) of its outer surface (the processed surface) under stagnant ambient.

  16. Influence of temperature on alkali stress adaptation in Listeria monocytogenes

    Science.gov (United States)

    Listeria monocytogenes cells may induce alkali stress adaptation when exposed to sublethal concentrations of alkaline cleaners and sanitizers that may be frequently used in the food processing environment. In the present study, the effect of temperature on the induction and the stability of such alk...

  17. Ambient temperature stress-corrosion cracking of sensitized stainless steels

    International Nuclear Information System (INIS)

    Sieradzki, K.; Isaacs, H.S.; Newman, R.C.

    1982-01-01

    Stress-corrosion cracking of sensitized Type 304 steel in low temperature borated water has been observed. The probable role of low levels of chloride ions or sulfur-containing ions is described, including the relationship of the phenomenon to polythionic acid cracking. The mechanism of the sulfur-induced cracking and its usefulness as a test for sensitization are outlined

  18. Analytical model of transient temperature and thermal stress in ...

    Indian Academy of Sciences (India)

    for certain tensile strain as modulus of elasticity increases. The most effective factor that may influence maximum hoop stress is the absorption coefficient, since it is the reciprocal of the effective depth that absorbs power. Increasing absorption power within a small depth means high temperature gradient and consequently, ...

  19. 20 CFR 416.1231 - Burial spaces and certain funds set aside for burial expenses.

    Science.gov (United States)

    2010-04-01

    ... spouse's, if any) burial expenses and kept separate from nonburial-related assets. Property other than.... Interest earned on excluded burial funds and appreciation in the value of excluded burial arrangements... exclusion of burial funds and accumulated interest and appreciation will continue to apply throughout a...

  20. Flow stress, subgrain size, and subgrain stability at elevated temperature

    International Nuclear Information System (INIS)

    Sherby, O.D.; Klundt, R.H.; Miller, A.K.

    1977-01-01

    Well defined subgrain boundaries dominate the microstructural changes occurring during plastic flow of polycrystalline metals at elevated temperature. The quantitative influence of subgrain size on elevated-temperature plastic flow is considered. Based on the results of tests under constant-stress and constant-structure conditions, and equation is developed which predicts the creep rate as a function of subgrain size, stress, diffusion coefficient, and elastic modulus. In general, the subgrain size is a unique function of the current modulus-compensated flow stress, but if fine subgrains can be introduced and stabilized, large increases in creep strength may result. The applicability of the phenomenological relation developed to the behavior of dispersion-strengthened materials (where the second-phase particles may predetermine the effective subgrain size) is discussed. When subgrain effects are included, it is shown that the creep rate is less dependent on stacking fault energy than has been previously thought

  1. Temperature effect on Zircaloy-4 stress corrosion cracking

    International Nuclear Information System (INIS)

    Farina, Silvia B.; Duffo, Gustavo S.; Galvele, Jose R.

    1999-01-01

    Stress corrosion cracking (SCC) susceptibility of Zircaloy-4 alloy in chloride, bromide and iodide solutions with variables as applied electrode potential, deformation rate and temperature have been studied. In those three halide solutions the susceptibility to SCC is only observed at potentials close to pitting potential, the crack propagation rate increases with the increase of deformation rate, and that the temperature has a notable effect only for iodide solutions. For chloride and bromide solutions and temperatures ranging between 20 to 90 C degrees it was not found measurable changes in crack propagation rates. (author)

  2. Elevated temperature stress strain behavior of beryllium powder product

    Energy Technology Data Exchange (ETDEWEB)

    Abeln, S.P.; Field, R. [Los Alamos National Lab., NM (United States); Mataya, M.C. [Safe Sites of Colorado, Golden, CO (United States)

    1995-09-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s{sup {minus}1} to 1 s{sup {minus}1}. Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data.

  3. Elevated temperature stress strain behavior of beryllium powder product

    International Nuclear Information System (INIS)

    Abeln, S.P.; Field, R.; Mataya, M.C.

    1995-01-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s -1 to 1 s -1 . Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data

  4. 3-D Temperature and Stress Simulations of Hardening Concrete

    DEFF Research Database (Denmark)

    Jensen, Poul; Buhr, Birit; Thorborg, Jesper

    2003-01-01

    When concrete is cast, heat develops. When the concrete cools down there is a risk that thermal gradients induce cracks in the structure. In the Middle East this is especially important as extensive heat builds up due to the high ambient temperatures. Possible formed cracks will have a detrimental...... effect on the overall durability of the structure, especially when placed in or close to a marine environment, and especially if placed in a hot and aggressive environment. In order to minimize the risk of inducing thermal cracks, temperature and stress requirements during the hardening period must...... for the thermo-mechanical conditions during hydration of early age concrete. Material properties as a function of maturity and environmental conditions form the basis of the model. This paper presents temperature and stress calculation results using MAGMAconcrete, and proposed hardening precautions for two...

  5. Stress-induced core temperature changes in pigeons (Columba livia).

    Science.gov (United States)

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Separating heat stress from moisture stress: analyzing yield response to high temperature in irrigated maize

    Science.gov (United States)

    Carter, Elizabeth K.; Melkonian, Jeff; Riha, Susan J.; Shaw, Stephen B.

    2016-09-01

    Several recent studies have indicated that high air temperatures are limiting maize (Zea mays L.) yields in the US Corn Belt and project significant yield losses with expected increases in growing season temperatures. Further work has suggested that high air temperatures are indicative of high evaporative demand, and that decreases in maize yields which correlate to high temperatures and vapor pressure deficits (VPD) likely reflect underlying soil moisture limitations. It remains unclear whether direct high temperature impacts on yields, independent of moisture stress, can be observed under current temperature regimes. Given that projected high temperature and moisture may not co-vary the same way as they have historically, quantitative analyzes of direct temperature impacts are critical for accurate yield projections and targeted mitigation strategies under shifting temperature regimes. To evaluate yield response to above optimum temperatures independent of soil moisture stress, we analyzed climate impacts on irrigated maize yields obtained from the National Corn Growers Association (NCGA) corn yield contests for Nebraska, Kansas and Missouri. In irrigated maize, we found no evidence of a direct negative impact on yield by daytime air temperature, calculated canopy temperature, or VPD when analyzed seasonally. Solar radiation was the primary yield-limiting climate variable. Our analyses suggested that elevated night temperature impacted yield by increasing rates of phenological development. High temperatures during grain-fill significantly interacted with yields, but this effect was often beneficial and included evidence of acquired thermo-tolerance. Furthermore, genetics and management—information uniquely available in the NCGA contest data—explained more yield variability than climate, and significantly modified crop response to climate. Thermo-acclimation, improved genetics and changes to management practices have the potential to partially or completely

  7. Jasmonates: emerging players in controlling temperature stress tolerance

    Directory of Open Access Journals (Sweden)

    Manvi eSharma

    2016-01-01

    Full Text Available The sedentary life of plants has forced them to live in an environment that is characterized by the presence of numerous challenges in terms of biotic and abiotic stresses. Phytohormones play essential roles in mediating plant physiology and alleviating various environmental perturbations. Jasmonates are a group of oxylipin compounds occurring ubiquitously in the plant kingdom that play pivotal roles in response to developmental and environmental cues. Jasmonates (JAs have been shown to participate in unison with key factors of other signal transduction pathway, including those involved in response to abiotic stress. Recent findings have furnished large body of information suggesting the role of jasmonates in cold and heat stress. JAs have been shown to regulate C-repeat binding factor (CBF pathway during cold stress. The interaction between the integrants of JA signaling and components of CBF pathway demonstrates a complex relationship between the two. JAs have also been shown to counteract chilling stress by inducing ROS avoidance enzymes. In addition, several lines of evidence suggest the positive regulation of thermotolerance by JA. The present review provides insights into biosynthesis, signal transduction pathway of jasmonic acid and their role in response to temperature stress.

  8. Attenuation of low-temperature stress in rice seedlings

    Directory of Open Access Journals (Sweden)

    Mara Grohs

    2016-06-01

    Full Text Available Rice is a cold-sensitive crop, and its exposure to low-temperature stress, during germination and early seedling growth, can negatively affect the initial stand establishment. Substances that act as growth regulators can be used to mitigate this initial stress. Thus, the influence of gibberellic acid, thiamethoxam and a phytohormone was investigated at the growth variables and antioxidant enzyme activity of the 'Irga 424' and 'Puita Inta CL' rice cultivars, at low-temperature (17 ºC. The products act on the germination percentage of 'Puita Inta CL', but vigor is only influenced by giberellic acid. Giberellic acid influences shoot length, irrespective of cultivar, while thiamethoxam and the phytohormone only affect length in 'Puita Inta CL'. The antioxidant activity depends on the cultivar and organ tested (shoot or root. These products mitigate the effects of cold, thereby preventing the formation of reactive-oxygen species and lipid peroxidation, and positively influence the superoxide dismutase enzyme activity.

  9. Report on waste burial charges

    International Nuclear Information System (INIS)

    1993-05-01

    One of the requirements placed upon nuclear power reactor licensees by the US Nuclear Regulatory Commission (NRC) is for the licensees to periodically adjust the estimate of the cost of decommissioning their plants, in dollars of the current year, as part of the process to provide reasonable assurance that adequate funds for decommissioning will be available when needed. This report, which is scheduled to be revised periodically, contains the development of a formula for escalating decommissioning cost estimates that is acceptable to the NRC. The sources of information to be used in the escalation formula are identified, and the values developed for the escalation of radioactive waste burial costs, by site and by year, are given. The licensees may use the formula, the coefficients, and the burial escalation factors from this report in their escalation analyses, or they may use an escalation rate at least equal to the escalation approach presented herein. This third revision of NUREG-1307 contains revised spreadsheet results for the disposal costs for the reference PWR and the reference BWR and the ratios of disposal costs at the Washington, Nevada, and South Carolina sites for the years 1986, 1988 and 1991, superseding the values given in the July 1991 issue of this report. Burial cost surcharges mandated by the Low-Level Radioactive Waste Policy Amendments Act of 1985 (LLRWPAA) have been incorporated into the revised ratio tables for those years. In addition, spreadsheet results for the disposal costs for the reference reactors and ratios of disposal costs at the two remaining burial sites in Washington and South Carolina for the year 1993 are provided. These latter results do not include any LLRWPAA surcharges, since those provisions of the Act expired at the end of 1992

  10. Textiles from Scythian burial complexes

    Directory of Open Access Journals (Sweden)

    Elena Fialko

    2013-12-01

    Full Text Available In Northern Black Sea steppes were excavated more than three thousand Scythian burial mounds. In the studied burials were discovered large quantities of artifacts, but leather and textile items are preserved only in a few cases. Some ideas about Scythian costume are found in the works of Greek authors. In this regard, extremely important is the funerary complex dated with the 4th century BC, discovered in barrow Vishnevaja Moghila (Zaporizhia region, Ukraine. In the crypt, which remained undisturbed over time, was found a burial of a Scythian girl. The unique condition of preservation of the textiles and leather findings allowed reconstructing the entire costume of the Scythian. It consisted of six layers of clothing. Various pieces of clothing were made from different materials: white linen cloth, orange satin fabric, reddish-brown fur, black cloth, fur, red skin. This discovery is one of a kind in the Northern Black Sea region, which is currently a reference example of female costume of early nomads of the region.

  11. FEM modelling of firing temperature and stress zones

    Energy Technology Data Exchange (ETDEWEB)

    Schulle, W.; Schultz, K. [Bergakademie Freiberg (Germany)

    1999-03-01

    In the introduction, the principal possibilities of using finite element modelling (FEM) for problem solving in the firing processes of ceramics are given. Subsequently, two concrete application examples are described. In the first example, the temperature and stress calculation during biscuit firing of porcelain is discussed. The results are given for the influence of the heating rate for stacked firing and single-layer firing of flat tableware, the influence of the positioning of the individual plates in the plate stack, and changes in shape of the article during the formation of temperature and stress fields could be estimated. In a second example, the heat stresses that arise during the firing of high voltage insulators were calculated. It can be shown how the progression of the stresses is influenced by the body geometry, especially with the insulators ''cup'' design. During the course of the firing process, a regulating influence is possible. The examples should encourage further problem solving by specific use of FEM. (orig.)

  12. Temperature changes during exercise stress testing in children with burns.

    Science.gov (United States)

    Mlcak, R P; Desai, M H; Robinson, E; McCauley, R L; Robson, M C; Herndon, D N

    1993-01-01

    It has been postulated that because of the extensive destruction of the skin and appendages after thermal injury, the thermoregulatory control mechanism would be impaired, and these patients would be intolerant to prolonged work. Preview studies demonstrate evidence that during work in a hot climate, patients with an extensively healed burn react with an excessive rise in body temperature. This study was designed to investigate the thermoregulatory response to exercise in pediatric patients with burns and to study changes in body temperature during exercise testing. Cardiopulmonary stress tests were completed in 32 children with a mean postburn time of 2.3 +/- 1.5 years and a mean burn size of 44% +/- 23% total body surface area. Exercise variables included expired volume, tidal volume, respiratory rate, tidal/dead space rate, heart rate, and work stage achieved. Temperature monitoring included external auditory canal temperature, burn scar, and normal skin temperature. Values were measured at baseline during and at maximum exercise. Our data indicate all patients reached the same endurance level regardless of the size of the total body surface area burn. Additionally, in a temperature-controlled environment, adequate heat dissipation in children with burns can be maintained during exercise testing without an excessive rise in body temperature.

  13. High temperature thermal creep under variable stress and temperature loading conditions

    International Nuclear Information System (INIS)

    Bocek, M.

    1985-01-01

    The present paper is concerned with thermal creep of cavitating materials subjected to time variable stresses and/or temperatures. Creep cavitation damage, because reducing the load bearing capability will influence the creep behavior of structures loaded by tension. The calculations are based on a phenomenological cavitation damage model, from which the life fraction rule (LFR) is deduced. For complex stress/temperature loading conditions by means of the LFR analytical expressions for the corresponding lifetimes are derived. Only stationary stress rupture data together with the loading conditions enter the computations. In the present procedure the damage function A(t), as a variable structure parameter, enters a constitutive strain rate/stress equation through an effective (true) stress. The latter, for given loading conditions, is derived from the solution of the general tensile test equation. Solving the strain rate/stress equation in terms of strain or time, the constitutive creep equation for ideally plastic cavitating materials exposed to non-stationary loading conditions are derived

  14. Analytical Methods for Temperature Field and Temperature Stress of Column Pier under Solar Radiation

    Directory of Open Access Journals (Sweden)

    Yin-hui Wang

    2015-01-01

    Full Text Available Based on the previous research work, a new idea is proposed for analyzing the impact of solar radiation on the substructure of bridges. Investigation is conducted in the thermodynamic phenomena and temperature stress of a dual-column pier. Research is led to the thermal conductivity of concrete structure and the values of the environmental parameters under solar radiation. An analytical code is written for the thermal analysis of the dual-column pier using the parametric modeling function of FE software, by means of which the temperature distribution of the bridge structure is computed under solar radiation. Using the thermal analytical results, the temperature stress of the dual-column pier is further calculated. The results tell that the temperature gradient distribution curve inside the concrete of the pier fits favorably the curve defined in the design specification and coincides quite well with real situation, which verifies the new idea proposed in this paper. Under the solar radiation which is a time-variable nonlinear temperature load to the bridge, the maximum principal stress is found at the corner of the pier with the sign of negative, which is believed to threaten the safety of the substructure of bridge and is necessary to arouse emphasis.

  15. 20 CFR 61.205 - Burial expense.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Burial expense. 61.205 Section 61.205... § 61.205 Burial expense. (a) When the death of a person listed in § 61.1(a) results from an injury caused by a war-risk hazard, the Office shall pay reasonable burial expenses up to the amount specified...

  16. Burial diagenesis of deep sea chalk as reflected in Biot’s coefficient

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Alam, Mohammad Monzurul

    to limestone as burial increases and porosity decreases. The porosity decrease is accompanied by an increasing velocity to elastic waves, and consequently a decreasing Biot’s coefficient, as estimated from velocity and density of core samples. When the effective burial stress is normalized to total horizontal...... cross sectional area, the porosity is found to decline as a function of stress. The porosity trend proceeds smoothly from ooze over chalk to limestone. By contrast, when vertical effective stress is normalized to grain contact area, each lithology shows a distinct porosity-decline - stress pattern...... indicate that by normalizing effective stress to grain contact area, we can get information about the mechanism behind burial related diagenetic porosity decline....

  17. Burial diagenesis of deep sea chalk as reflected in Biot's coefficient

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Alam, Mohammad Monzurul

    2013-01-01

    to limestone as burial increases and porosity decreases. The porosity decrease is accompanied by an increasing velocity to elastic waves, and consequently a decreasing Biot's coefficient, as estimated from velocity and density of core samples. When the effective burial stress is normalized to total horizontal...... cross sectional area, the porosity is found to decline as a function of stress. The porosity trend proceeds smoothly from ooze over chalk to limestone. By contrast, when vertical effective stress is normalized to grain contact area, each lithology shows a distinct porosity-decline - stress pattern...... indicate that by normalizing effective stress to grain contact area, we can get information about the mechanism behind burial related diagenetic porosity decline....

  18. Carbon sequestration via wood burial

    Directory of Open Access Journals (Sweden)

    Zeng Ning

    2008-01-01

    Full Text Available Abstract To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a sustainable long-term carbon sequestration potential for wood burial is 10 ± 5 GtC y-1, and currently about 65 GtC is on the world's forest floors in the form of coarse woody debris suitable for burial. The potential is largest in tropical forests (4.2 GtC y-1, followed by temperate (3.7 GtC y-1 and boreal forests (2.1 GtC y-1. Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from North American logging industry, the cost for wood burial is estimated to be $14/tCO2($50/tC, lower than the typical cost for power plant CO2 capture with geological storage. The cost for carbon sequestration with wood burial is low because CO2 is removed from the atmosphere by the natural process of photosynthesis at little cost. The technique is low tech, distributed, easy to monitor, safe, and reversible, thus an attractive option for large-scale implementation in a world-wide carbon market.

  19. Land-use change, not climate, controls organic carbon burial in lakes.

    Science.gov (United States)

    Anderson, N J; Dietz, R D; Engstrom, D R

    2013-10-22

    Lakes are a central component of the carbon cycle, both mineralizing terrestrially derived organic matter and storing substantial amounts of organic carbon (OC) in their sediments. However, the rates and controls on OC burial by lakes remain uncertain, as do the possible effects of future global change processes. To address these issues, we derived OC burial rates in (210)Pb-dated sediment cores from 116 small Minnesota lakes that cover major climate and land-use gradients. Rates for individual lakes presently range from 7 to 127 g C m(-2) yr(-1) and have increased by up to a factor of 8 since Euro-American settlement (mean increase: 2.8×). Mean pre-disturbance OC burial rates were similar (14-22 g C m(-2) yr(-1)) across all land-cover categories (prairie, mixed deciduous and boreal forest), indicating minimal effect of the regional temperature gradient (approx. 4 °C) on background carbon burial. The relationship between modern OC burial rates and temperature was also not significant after removal of the effect of total phosphorus. Contemporary burial rates were strongly correlated with lake-water nutrients and the extent of agricultural land cover in the catchment. Increased OC burial, documented even in relatively undisturbed boreal lake ecosystems, indicates a possible role for atmospheric nitrogen deposition. Our results suggest that globally, future land-cover change, intensification of agriculture and associated nutrient loading together with atmospheric N-deposition will enhance OC sequestration by lakes.

  20. Stress Free Temperature Testing and Residual Stress Calculations on Out-of-Autoclave Composites

    Science.gov (United States)

    Cox, Sarah; Tate, LaNetra C.; Danley, Susan; Sampson, Jeff; Taylor, Brian; Miller, Sandi

    2012-01-01

    Future launch vehicles will require the incorporation large composite parts that will make up primary and secondary components of the vehicle. NASA has explored the feasibility of manufacturing these large components using Out-of-Autoclave impregnated carbon fiber composite systems through many composites development projects. Most recently, the Composites for Exploration Project has been looking at the development of a 10 meter diameter fairing structure, similar in size to what will be required for a heavy launch vehicle. The development of new material systems requires the investigation of the material properties and the stress in the parts. Residual stress is an important factor to incorporate when modeling the stresses that a part is undergoing. Testing was performed to verify the stress free temperature with two-ply asymmetric panels. A comparison was done between three newly developed out of autoclave IM7 /Bismalieimide (BMI) systems. This paper presents the testing results and the analysis performed to determine the residual stress of the materials.

  1. Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

    Directory of Open Access Journals (Sweden)

    Chrysochoos A.

    2010-06-01

    Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

  2. Carbon Sequestration via Wood Burial

    Science.gov (United States)

    Zeng, N.

    2007-12-01

    To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which forest dead wood or old trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It was estimated that the carbon sequestration potential of forest wood harvest and burial is 10GtC y-1 with an uncertainty range of 5-15 GtC y-1. Based on data from North American logging industry, the cost was crudely estimated at $50/tC, significantly lower than the cost for power plant CO2 capture with geological storage, a carbon sequestration technique currently under most serious consideration. The low cost is largely because the CO2 capture is achieved at little cost by the natural process of photosynthesis. The technique is low tech, distributed, safe and can be stopped or reversed at any time. The relatively low cost may soon be competitive enough for large-scale implementation in a world-wide carbon trading market. In tropical regions with ongoing deforestation, wood burial instead of burning will immediately reduce that portion of the anthropogenic CO2 emission.

  3. [Effect of shifting sand burial on evaporation reduction and salt restraint under saline water irrigation in extremely arid region].

    Science.gov (United States)

    Zhang, Jian-Guo; Zhao, Ying; Xu, Xin-Wen; Lei, Jia-Qiang; Li, Sheng-Yu; Wang, Yong-Dong

    2014-05-01

    The Taklimakan Desert Highway Shelterbelt is drip-irrigated with high saline groundwater (2.58-29.70 g x L(-1)), and shifting sand burial and water-salt stress are most common and serious problems in this region. So it is of great importance to study the effect of shifting sand burial on soil moisture evaporation, salt accumulation and their distribution for water saving, salinity restraint, and suitable utilization of local land and water resources. In this study, Micro-Lysimeters (MLS) were used to investigate dynamics of soil moisture and salt under different thicknesses of sand burial (1, 2, 3, 4, and 5 cm), and field control experiments of drip-irrigation were also carried out to investigate soil moisture and salt distribution under different thicknesses of shifting sand burial (5, 10, 15, 20, 25, 30, 35, and 40 cm). The soil daily and cumulative evaporation decreased with the increase of sand burial thickness in MLS, cumulative evaporation decreased by 2.5%-13.7% compared with control. And evaporative inhibiting efficiency increased with sand burial thickness, evaporative inhibiting efficiency of 1-5 cm sand burial was 16.7%-79.0%. Final soil moisture content beneath the interface of sand burial increased with sand burial thickness, and it increased by 2.5%-13.7% than control. The topsoil EC of shifting sand in MLS decreased by 1.19-6.00 mS x cm(-1) with the increasing sand burial thickness, whereas soil salt content beneath the interface in MLS increased and amplitude of the topsoil salt content was higher than that of the subsoil. Under drip-irrigation with saline groundwater, average soil moisture beneath the interface of shifting sand burial increased by 0.4% -2.0% compare with control, and the highest value of EC was 7.77 mS x cm(-1) when the sand burial thickness was 10 cm. The trend of salt accumulation content at shifting sand surface increased firstly, and then decreased with the increasing sand burial thickness. Soil salt contents beneath the

  4. Sediment Burial Intolerance of Marine Macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  5. Sediment Burial Intolerance of Marine Macroinvertebrates.

    Science.gov (United States)

    Hendrick, Vicki J; Hutchison, Zoë L; Last, Kim S

    2016-01-01

    The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura), the queen scallop (Aequipecten opercularis) and the sea squirt (Ciona intestinalis) were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris) and the anemone (Sagartiogeton laceratus), showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa). With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally, and perhaps

  6. Efficient egress of escaping ants stressed with temperature.

    Directory of Open Access Journals (Sweden)

    Santiago Boari

    Full Text Available In the present work we investigate the egress times of a group of Argentine ants (Linepithema humile stressed with different heating speeds. We found that the higher the temperature ramp is, the faster ants evacuate showing, in this sense, a group-efficient evacuation strategy. It is important to note that even when the life of ants was in danger, jamming and clogging was not observed near the exit, in accordance with other experiments reported in the literature using citronella as aversive stimuli. Because of this clear difference between ants and humans, we recommend the use of some other animal models for studying competitive egress dynamics as a more accurate approach to understanding competitive egress in human systems.

  7. Creep stresses in a spherical shell under steady state temperature

    Science.gov (United States)

    Verma, Gaurav; Rana, Puneet

    2017-10-01

    The paper investigates the problem of creep of a spherical structure under the influence of steady state temperature. The problem of creep in spherical shell is solved by using the concept of generalized strain measures and transition hypothesis given by Seth. The problem has reduced to non-linear differential equation for creep transition. This paper deals with the non-linear behaviour of spherical shell under thermal condition. The spherical shell structures are easily vulnerable to creep, shrinkage and thermal effects; a thorough understanding of their time-dependent behaviour has been fully established. The paper aims to provide thermal creep analysis to enhance the effective design and long life of shells, and a theoretical model is developed for calculating creep stresses and strains in a spherical shell with purpose. Results obtained for the problem are depicted graphically.

  8. Heat Priming Induces Trans-generational Tolerance to High Temperature Stress in Wheat

    OpenAIRE

    Wang, Xiao; Xin, Caiyun; Cai, Jian; Zhou, Qin; Dai, Tingbo; Cao, Weixing; Jiang, Dong

    2016-01-01

    Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the tran...

  9. PHYSIOLOGICAL RESPONSE OF SOME TOMATO GENOTYPES (LYCOPERSICON ESCULENTUM L. TO HIGH TEMPERATURE STRESS

    Directory of Open Access Journals (Sweden)

    Malgorzata BEROVA

    2009-06-01

    Full Text Available Cultivated plants are often exposed to different types of environmental stress, which limits their development and productivity. High temperature stress induces considerable changes in the biochemistry and physiology of plants. The aim of the present investigation was to evaluate the physiological response of some tomato genotypes to a high temperature stress. Experiments were carried out during the stress period and after its elimination. Valuation of the tolerance of plants was carried out by means of a physiological test. It was observed that the high temperature stress has an inhibitory effect on the physiological state of tomato plants. The degree of its inhibited action was individual, depending on the genotype.

  10. Cleanup Verification Package for the 618-2 Burial Ground

    International Nuclear Information System (INIS)

    Thompson, W.S.

    2006-01-01

    This cleanup verification package documents completion of remedial action for the 618-2 Burial Ground, also referred to as Solid Waste Burial Ground No. 2; Burial Ground No. 2; 318-2; and Dry Waste Burial Site No. 2. This waste site was used primarily for the disposal of contaminated equipment, materials and laboratory waste from the 300 Area Facilities

  11. Cleanup Verification Package for the 618-2 Burial Ground

    Energy Technology Data Exchange (ETDEWEB)

    W. S. Thompson

    2006-12-28

    This cleanup verification package documents completion of remedial action for the 618-2 Burial Ground, also referred to as Solid Waste Burial Ground No. 2; Burial Ground No. 2; 318-2; and Dry Waste Burial Site No. 2. This waste site was used primarily for the disposal of contaminated equipment, materials and laboratory waste from the 300 Area Facilities.

  12. Solid waste burial grounds interim safety analysis

    International Nuclear Information System (INIS)

    Saito, G.H.

    1994-01-01

    This Interim Safety Analysis document supports the authorization basis for the interim operation and restrictions on interim operations for the near-surface land disposal of solid waste in the Solid Waste Burial Grounds. The Solid Waste Burial Grounds Interim Safety Basis supports the upgrade progress for the safety analysis report and the technical safety requirements for the operations in the Solid Waste Burial Grounds. Accident safety analysis scenarios have been analyzed based on the significant events identified in the preliminary hazards analysis. The interim safety analysis provides an evaluation of the operations in the Solid Waste Burial Grounds to determine if the radiological and hazardous material exposures will be acceptable from an overall health and safety standpoint to the worker, the onsite personnel, the public, and the environment

  13. Solid waste burial grounds interim safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Saito, G.H.

    1994-10-01

    This Interim Safety Analysis document supports the authorization basis for the interim operation and restrictions on interim operations for the near-surface land disposal of solid waste in the Solid Waste Burial Grounds. The Solid Waste Burial Grounds Interim Safety Basis supports the upgrade progress for the safety analysis report and the technical safety requirements for the operations in the Solid Waste Burial Grounds. Accident safety analysis scenarios have been analyzed based on the significant events identified in the preliminary hazards analysis. The interim safety analysis provides an evaluation of the operations in the Solid Waste Burial Grounds to determine if the radiological and hazardous material exposures will be acceptable from an overall health and safety standpoint to the worker, the onsite personnel, the public, and the environment.

  14. Decommissioning and decontamination (burial ground stabilization) studies

    International Nuclear Information System (INIS)

    Cline, J.F.

    1980-01-01

    The decommissioning and decontamination of retired Hanford facilities and the future use of surrounding landscapes require isolation of contaminated wastes from the biosphere. Burial ground stabilization studies were conducted to determine the effectiveness of physical barriers for isolating contaminated wastes in shallow-land burial sites from plants and animals. This study was undertaken to determine the effectiveness of using a layer of loose rock between the waste and the surface soil covering to prevent both plant root and animal penetrations

  15. Temperature dependence of stress in CVD diamond films studied by Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Dychalska Anna

    2015-09-01

    Full Text Available Evolution of residual stress and its components with increasing temperature in chemical vapor deposited (CVD diamond films has a crucial impact on their high temperature applications. In this work we investigated temperature dependence of stress in CVD diamond film deposited on Si(100 substrate in the temperature range of 30 °C to 480 °C by Raman mapping measurement. Raman shift of the characteristic diamond band peaked at 1332 cm-1 was studied to evaluate the residual stress distribution at the diamond surface. A new approach was applied to calculate thermal stress evolution with increasing tempera­ture by using two commonly known equations. Comparison of the residts obtained from the two methods was presented. The intrinsic stress component was calculated from the difference between average values of residual and thermal stress and then its temperature dependence was discussed.

  16. Net carbon allocation in soybean seedlings as influenced by soil water stress at two soil temperatures

    International Nuclear Information System (INIS)

    McCoy, E.L.; Boersma, L.; Ekasingh, M.

    1990-01-01

    The influence of water stress at two soil temperatures on allocation of net photoassimilated carbon in soybean (Glycine max [L.] Merr.) was investigated using compartmental analysis. The experimental phase employed classical 14 C labeling methodology with plants equilibrated at soil water potentials of -0.04, -0.25 and -0.50 MPa; and soil temperatures of 25 and 10C. Carbon immobilization in the shoot apex generally followed leaf elongation rates with decreases in both parameters at increasing water stress at both soil temperatures. However, where moderate water stress resulted in dramatic declines in leaf elongation rates, carbon immobilization rates were sharply decreased only at severe water stress levels. Carbon immobilization was decreased in the roots and nodules of the nonwater stressed treatment by the lower soil temperature. This relation was reversed with severe water stress, and carbon immobilization in the roots and nodules was increased at the lower soil temperature. Apparently, the increased demand for growth and/or carbon storage in these tissues with increased water stress overcame the low soil temperature limitations. Both carbon pool sizes and partitioning of carbon to the sink tissues increased with moderate water stress at 25C soil temperature. Increased pool sizes were consistent with whole plant osmotic adjustment at moderate water stress. Increased partitioning to the sinks was consistent with carbon translocation processes being less severely influenced by water stress than is photosynthesis

  17. The Varying Effects of Uniaxial Compressive Stress on the Bainitic Transformation under Different Austenitization Temperatures

    Directory of Open Access Journals (Sweden)

    Mingxing Zhou

    2016-05-01

    Full Text Available In this study, thermal simulation experiments under different austenitization temperatures and different stress states were conducted. High-temperature laser scanning confocal microscopy (LSCM, thermal dilatometry, and scanning electron microscope (SEM were used to quantitatively investigate the effects of the uniaxial compressive stress on bainitic transformation at 330 °C following different austenitization temperatures. The transformation plasticity was also analyzed. It was found that the promotion degree of stress on bainitic transformation increases with the austenitization temperature due to larger prior austenite grain size as well as stronger promoting effect of mechanical driving force on selected variant growth at higher austenitization temperatures. The grain size and the yield strength of prior austenite are other important factors which influence the promotion degree of stress on bainitic transformation, besides the mechanical driving force provided by the stress. Moreover, the transformation plasticity increases with the austenitization temperature.

  18. Shallow land burial technology: humid

    International Nuclear Information System (INIS)

    Davis, E.C.; Yeh, G.T.

    1984-01-01

    Applying engineered modifications to present shallow land burial (SLB) practices is one method of ensuring safe operation and improving overall disposal-site performance. Two such engineered modifications, trench lining and grouting, are being demonstrated and evaluated at the Oak Ridge National Laboratory (ORNL) Engineered Test Facility (ETF), using nine 28-m 3 experimental trenches containing compacted low-level waste (LLW). Concurrent to this field demonstration experiment, two finite-element hydrologic models have been developed to model water movement and solute transport at a waste disposal site. This paper covers progress made in these two areas during FY 1984. Though the economic analysis of the two trench treatments favored Hypalon lining (lining costs were 33% lower at this demonstration scale), results of field experiments examining waste hydrologic isolation favored the cement-bentonite grout treatment. Data from water pump-out and water pump-in tests, combined with observed intratrench water-level fluctuations, suggest that the original goal of constructing watertight liners in three experimental trenches was not achieved. In addition, trench-cover subsidence of approx. 2% of the total trench depth has been measured over two of the three lined trenches but has not occurred over any of the three grouted or three control (untreated) trenches. The evaluation of the two trench treatments is continuing. However, results indicate that the cement-bentonite treatment, implemented at a cost of $160/m 3 of grout, provides a degree of waste isolation not afforded by the lined and control trenches and should be considered for use at SLB sites with water-related problems. 11 references, 6 figures, 2 tables

  19. Thermometry, calorimetry, and mean body temperature during heat stress.

    Science.gov (United States)

    Kenny, Glen P; Jay, Ollie

    2013-10-01

    Heat balance in humans is maintained at near constant levels through the adjustment of physiological mechanisms that attain a balance between the heat produced within the body and the heat lost to the environment. Heat balance is easily disturbed during changes in metabolic heat production due to physical activity and/or exposure to a warmer environment. Under such conditions, elevations of skin blood flow and sweating occur via a hypothalamic negative feedback loop to maintain an enhanced rate of dry and evaporative heat loss. Body heat storage and changes in core temperature are a direct result of a thermal imbalance between the rate of heat production and the rate of total heat dissipation to the surrounding environment. The derivation of the change in body heat content is of fundamental importance to the physiologist assessing the exposure of the human body to environmental conditions that result in thermal imbalance. It is generally accepted that the concurrent measurement of the total heat generated by the body and the total heat dissipated to the ambient environment is the most accurate means whereby the change in body heat content can be attained. However, in the absence of calorimetric methods, thermometry is often used to estimate the change in body heat content. This review examines heat exchange during challenges to heat balance associated with progressive elevations in environmental heat load and metabolic rate during exercise. Further, we evaluate the physiological responses associated with heat stress and discuss the thermal and nonthermal influences on the body's ability to dissipate heat from a heat balance perspective.

  20. An expression for transient thermal stress in a nonhomogeneous plate with temperature variation through thickness

    International Nuclear Information System (INIS)

    Sugano, Y.

    1987-01-01

    An expression for nonzero thermal stress in a nonhomogeneous flat plate with arbitrary variation in mechanical properties is presented under a transient temperature distribution. Especially an equation for nonzero thermal stress and its numerical calculation showing the effect of nonhomogeneous thermal and mechanical properties on temperature and thermal stress distribution, is given for the case of an exponentially varying thermal conductivity and Young's modulus, but for a homogeneous Poisson's ratio and coefficient of linear thermal expansion. (orig.) [de

  1. Shallow land burial of radioactive wastes

    International Nuclear Information System (INIS)

    Jacobs, D.G.; Rose, R.R.

    1985-01-01

    The authors discuss low-level, solid radioactive wastes buried in the ground since the startup of nuclear operations by the Manhattan Engineer District in the early 1940's. These operations were originally intended to be temporary so the primary consideration in locating land burial sites was their accessibility from the source of waste production. Early land-burial facilities were located on large reservations owned by the U.S. Atomic Energy Commission (AEC) and operated by their prime contractors. Shallow land burial consists of excavating a trench or vault, emplacing the waste, minimizing void space within the disposal unit, and covering the waste with earth to control access to the waste. Problems encountered in the land-burial of radioactive wastes are classified into areas which relate to the environmental characteristics of the sites, waste characteristics, operational practices and control, and predictive capability. The most serious environmentally related problems involve water management. Water provides primary vehicle for both erosional processes, which affect the structural integrity of the waste trenches, and for the migration of radionuclides. Although there is consensus that the current level of off-site movement of radionuclides from operating burial grounds does not constitute an immediate health hazard, there is less certainty with respect to the ability of the facilities to provide long-term containment and isolation

  2. Temperature/Stress Distributions in a Stress-Relief-Type Plate of Functionally Graded Materials under Thermal Shock

    Science.gov (United States)

    Awaji, Hideo; Takenaka, Hiromitsu; Honda, Sawao; Nishikawa, Tadahiro

    This paper presents a numerical technique for analyzing one-dimensional transient temperature and stress distributions in a stress-relief-type plate of functionally graded ceramic-metal based materials (FGMs), in relation to both the temperature-dependent thermal properties and continuous and gradual variation of the thermo-mechanical properties of the FGM. The FGM plate is assumed to be initially in steady state of temperature gradient, suffering high temperature at the ceramic side and low temperature at the metallic side associated with its in-service performance. The FGM plate is then rapidly cooled at the ceramic side of the plate by a cold medium. The transient temperature and related thermal stresses in the FGM plate are analyzed numerically for a model alumina-nickel FGM system. The proposed analytical technique for determining the temperature distribution is quite simple and widely applicable for various boundary conditions of FGMs, compared with methods recently proposed by other researchers. The optimum composition of FGMs is also discussed to reduce the thermal stresses in the FGM plate, relating to the function of the volume fraction of the metal across the thickness.

  3. Impact of heat stress on crop yield—on the importance of considering canopy temperature

    International Nuclear Information System (INIS)

    Siebert, Stefan; Ewert, Frank; Eyshi Rezaei, Ehsan; Kage, Henning; Graß, Rikard

    2014-01-01

    Increasing crop productivity while simultaneously reducing the environmental footprint of crop production is considered a major challenge for the coming decades. Even short episodes of heat stress can reduce crop yield considerably causing low resource use efficiency. Studies on the impact of heat stress on crop yields over larger regions generally rely on temperatures measured by standard weather stations at 2 m height. Canopy temperatures measured in this study in field plots of rye were up to 7 °C higher than air temperature measured at typical weather station height with the differences in temperatures controlled by soil moisture contents. Relationships between heat stress and grain number derived from controlled environment studies were only confirmed under field conditions when canopy temperature was used to calculate stress thermal time. By using hourly mean temperatures measured by 78 weather stations located across Germany for the period 1994–2009 it is estimated, that mean yield declines in wheat due to heat stress during flowering were 0.7% when temperatures are measured at 2 m height, but yield declines increase to 22% for temperatures measured at the ground. These results suggest that canopy temperature should be simulated or estimated to reduce uncertainty in assessing heat stress impacts on crop yield. (letter)

  4. Pulmonary artery and intestinal temperatures during heat stress and cooling

    DEFF Research Database (Denmark)

    Pearson, James; Ganio, Matthew S; Seifert, Thomas

    2012-01-01

    In humans, whole body heating and cooling are used to address physiological questions where core temperature is central to the investigated hypotheses. Core temperature can be measured in various locations throughout the human body. The measurement of intestinal temperature is increasingly used i...

  5. Internal stress analysis of Cu/W composite by low temperature neutron in-situ measurement

    International Nuclear Information System (INIS)

    Nishida, Masayuki; Muslih, M. Refai; Minakawa, Nobuaki; Ikeuchi, Yasukazu; Hanabusa, Takao

    2004-01-01

    Properties of fiber-reinforced materials depend strongly on internal stress state due to residual stress caused by difference in thermal expansion coefficient between fibers and matrix. In this study, performance of the neutron diffraction apparatus of BATAN, a low temperature neutron in-situ measurement apparatus, was tested in comparison with similar one of JAERI, by measuring internal stress of Cu/W composite fabricated for this experiment was tested. The composite specimens were loaded by low temperature thermal cycles using a cryostat and the stress was in-situ measured. Strong [110] orientation was observed in W fibers. The initial stress in W fibers was about -400 MPa in compression state along fiber direction, and it changed from -600 MPa to -80 MPa with temperatures. The experiment showed that the apparatus of BATAN was available to measure the internal stress. (A. Hishinuma)

  6. Overexpression of monoubiquitin improves photosynthesis in transgenic tobacco plants following high temperature stress.

    Science.gov (United States)

    Tian, Fengxia; Gong, Jiangfeng; Zhang, Jin; Feng, Yanan; Wang, Guokun; Guo, Qifang; Wang, Wei

    2014-09-01

    The ubiquitin/26S proteasome system (Ub/26S) is implicated in abiotic stress responses in plants. In this paper, transgenic tobacco plants overexpressing Ta-Ub2 from wheat were used to study the functions of Ub in the improvement of photosynthesis under high temperature (45°C) stress. We observed higher levels of Ub conjugates in transgenic plants under high temperature stress conditions compared to wild type (WT) as a result of the constitutive overexpression of Ta-Ub2, suggesting increased protein degradation by the 26S proteasome system under high temperature stress. Overexpressing Ub increased the photosynthetic rate (Pn) of transgenic tobacco plants, consistent with the improved ATPase activity in the thylakoid membrane and enhanced efficiency of PSII photochemistry. The higher D1 protein levels following high temperature stress in transgenic plants than WT were also observed. These findings imply that Ub may be involved in tolerance of photosynthesis to high temperature stress in plants. Compared with WT, the transgenic plants showed lower protein carbonylation and malondialdehyde (MDA) levels, less reactive oxygen species (ROS) accumulation, but higher antioxidant enzyme activity under high temperature stress. These findings suggest that the improved antioxidant capacity of transgenic plants may be one of the most important mechanisms underlying Ub-regulated high temperature tolerance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. De novo assembly and characterization of stress transcriptome and regulatory networks under temperature, salt and hormone stresses in Lilium lancifolium.

    Science.gov (United States)

    Wang, Jingmao; Wang, Qing; Yang, Yang; Liu, Xiaohua; Gu, Jiahui; Li, Wenqi; Ma, Suliya; Lu, Yingmin

    2014-12-01

    Plants have continually confrontation with different abiotic stresses, including salt, low temperature, drought or hormone stress. The plants acclimate to the environmental stresses relating with the falls of the molecular mesh including the stress signal receiver, signal transcriptional regulation and the expression of functional and structure genes. Using the RNA-seq, we carried out a transcriptional analysis under cold treatment for investigating a profound comprehension of the signal network and molecular metabolisms reaction included in abiotic stress reaction for Lilium lancifolium. Our study identified 18,722 unigenes had demonstrated the resemblance to the known exact proteins in the Swiss-Prot protein database and classified them by Gene ontology into three primary kinds: cellular component, biological process, and molecular function, and then 15,898 unigenes aligned to existing sequences in the KEGG databases. Based on the transcriptome results of cold stress, more stress-related genes were identified and analyzed of their expressions in other abiotic stress treatments as 37 °C, ABA, JA and Na. Meanwhile, bioinformatics qRT-PCR analyses of stress genes as LlDREB1, LlAP2, LlNAC1, LlHOT, LlR2R3-MYB and LlCDPK revealed that novel candidate genes encoding ethylene responsive transporters and serine/threonine receptor-like kinases, which contributed to speculate the signal regulation pathway during the abiotic stresses; engineering genes could also boost the tolerance to stress, as protected and maintained the function and structure of cellular components. Our research conjectured the abiotic stress signal transduction pathway and identified the expected key ingredients regulating the stress tolerance in Lilium lancifolium, which would enable the in-depth molecular exploration of stress-tolerance mechanisms in lily.

  8. Modelling of composition and stress profiles in low temperature surface engineered stainless steel

    DEFF Research Database (Denmark)

    Jespersen, Freja Nygaard; Hattel, Jesper Henri; Somers, Marcel A. J.

    2015-01-01

    stresses are introduced in the developing case, arising from the volume expansion that accompanies the dissolution of high interstitial contents in expanded austenite. Modelling of the composition and stress profiles developing during low temperature surface engineering from the processing parameters...... temperature, time and gas composition is a prerequisite for targeted process optimization. A realistic model to simulate the developing case has to take the following influences on composition and stress into account: - a concentration dependent diffusion coefficient - trapping of nitrogen by chromium atoms...... - the effect of residual stress on diffusive flux - the effect of residual stress on solubility of interstitials - plastic accommodation of residual stress. The effect of all these contributions on composition and stress profiles will be addressed....

  9. Non-uniform temperature gradients and thermal stresses produced ...

    Indian Academy of Sciences (India)

    induced stress distributions in a hollow steel sphere heated by a moving uniform heat source applied on a certain zenithal segment (the heated zenithal segment, Θ H ) of its outer surface (the processed surface) under stagnant ambient ...

  10. Drought, salt, and temperature stress-induced metabolic rearrangements and regulatory networks

    Science.gov (United States)

    Krasensky, Julia; Jonak, Claudia

    2015-01-01

    Plants regularly face adverse growth conditions, such as drought, salinity, chilling, freezing, and high temperatures. These stresses can delay growth and development, reduce productivity, and, in extreme cases, cause plant death. Plant stress responses are dynamic and involve complex cross-talk between different regulatory levels, including adjustment of metabolism and gene expression for physiological and morphological adaptation. In this review, information about metabolic regulation in response to drought, extreme temperature, and salinity stress is summarized and the signalling events involved in mediating stress-induced metabolic changes are presented. PMID:22291134

  11. Metabolomic signatures of inbreeding at benign and stressful temperatures in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Pedersen, Kamilla Sofie; Kristensen, Torsten Nygaard; Loeschcke, Volker

    2008-01-01

    to an increased between-line variation in metabolite profiles compared to outbred lines. In contrast to previous observations revealing interactions between inbreeding and environmental stress on gene expression patterns and life-history traits, the effect of inbreeding on the metabolite profile was similar...... and five inbred lines were studied by nuclear magnetic resonance spectroscopy after exposure to benign temperature, heat stress, or cold stress. In both the absence and the presence of temperature stress, metabolite levels were significantly different among inbred and outbred lines. The major effect...

  12. Drought, salt, and temperature stress-induced metabolic rearrangements and regulatory networks.

    Science.gov (United States)

    Krasensky, Julia; Jonak, Claudia

    2012-02-01

    Plants regularly face adverse growth conditions, such as drought, salinity, chilling, freezing, and high temperatures. These stresses can delay growth and development, reduce productivity, and, in extreme cases, cause plant death. Plant stress responses are dynamic and involve complex cross-talk between different regulatory levels, including adjustment of metabolism and gene expression for physiological and morphological adaptation. In this review, information about metabolic regulation in response to drought, extreme temperature, and salinity stress is summarized and the signalling events involved in mediating stress-induced metabolic changes are presented.

  13. A threshold stress for high-temperature plastic flow in WC-CO cemented carbides

    Science.gov (United States)

    Lee, In-Chul

    1995-04-01

    The logarithmic relationship between flow stress and strain rate in WC-Co cemented carbides is represented by a signoidal curve at a constant temperature and is divided into three regions, as in superplastic metals. The flow stress in region I has no dependence on both carbide grain size and binder content, indicative of the presence of a threshold stress for high-temperature plastic flow in cemented carbides. The threshold stress estimated by extrapolating the plot of ɛm against σ to zero strain rate has a strong dependence on temperature. The logarithmic plot of the effective stress compensated by the threshold stress against strain rate shows a single straight line for region I and region II at a constant temperature, which suggests that the regions I and II are controlled by the same deformation process i.e. the grain boundary sliding in WC/WC boundaries. A small addition of Cr3C2 and VC gives rise to the outstanding increase in flow stress in region I and subsequently results in the marked increase in the threshold stress. The origin of the threshold stress in WC-Co cemented carbides is closely related to the impurity elements or the intensional additives such as Cr3C2 and VC.

  14. Measurement of water transfer and swelling stress in the buffer material due to temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokai, Ibaraki (Japan); Chijimatsu, M.; Fujita, A.

    1999-03-01

    Coefficients concerning the water transfer in the buffer material was obtained by empirically giving a temperature gradient, and the swelling stress was measured when water was soaked in the sample under the uniform temperature and temperature gradient conditions. The distributions of temperature and water in the buffer material empirically given a temperature gradient were measured to deduce water diffusion constant due to the temperature gradient. The diffusion constant was the order of 10{sup -8} cm{sup 2}/s/degC. As a result of a equitemperature soaking test, it was found that the swelling stress of the part where soaktion was slow was greater than that of the part with fast soaking at a stage of non-uniform water distribution. The water soaking quantity to the sample and swelling stress reached a stationary state after 7000 hours and the water distribution in the whole sample was found saturated. (H. Baba)

  15. Physiological and biochemical responses to low temperature stress ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-09

    Nov 9, 2011 ... temperatures (cold and freezing) for 24 h, or consecutive low temperatures (5°C, 0 to 120 h), to determine .... min (Aebi, 1984). CAT activity was calculated and expressed as nmol H2O2 mg-1 protein min-1. POD (EC 1.11.1.7) activity was measured using a modification of the method described by Chance.

  16. Wrack burial reduces germination and establishment of the invasive cordgrass Spartina densiflora

    Directory of Open Access Journals (Sweden)

    Ahmed Abbas

    2014-04-01

    Full Text Available Germination and emergence of halophytes may decrease significantly by seed burial in dead plant material, or wrack, which is common and abundant in tidal marshes. The effects of plant debris (wrack burial on seed germination and seedling establishment of Spartina densiflora, an invasive cordgrass, were studied under greenhouse conditions and compared with field observations. Five wrack burial depths were applied: control without wrack, 1 cm (1235 ± 92 g DW wrack m-2, 2 cm (3266 ± 13 g DW m-2, 4 cm (4213 ± 277 g DW m-2, and 8 cm (6138 ± 227 g DW m-2. Sediment pH, electrical conductivity, redox potential and temperature were recorded. Quiescence increased with wrack load up to ~20% at 8 cm deep. Germination decreased with wrack load from 96% to 14%, which could be related with anoxic conditions under the debris since sediment redox potential was as low as -83 ± 7 mV at 8 cm. Germination percentage increased and quiescent and dormant percentages decreased at higher daily sediment temperatures and with higher daily temperature fluctuations, conditions that were recorded without or under low loads of wrack. Spartina densiflora did not show primary dormancy, but its seeds entered into a non-deep physiological dormancy below 1 cm deep in plant debris. The establishment of S. densiflora seedlings was also greatly reduced by wrack burial since only 6 seedlings (11 ± 5 % of germinated seeds emerged above plant debris from 1 cm and all seedlings died from deeper than 1 cm. S. densiflora seedling development was also reduced by wrack burial. The inverse relationship between germination and emergence of S. densiflora with wrack burial recorded in our study is useful to predict its invasion dynamics and to plan the management of invaded marshes.

  17. Effect of intergranular stress on yielding of 316H during room temperature cyclic loading

    International Nuclear Information System (INIS)

    Assessment of cyclic deformation is an integral part of nuclear power plant life assessment code, as many of the components in plant go through scheduled and unscheduled cyclic deformation owing to varying thermal and mechanical stresses. In polycrystalline material like 316H, a type of micro stress known as intergranular stress is generated due to elastic and plastic anisotropies during such cyclic loading. In tension-compression loading cycles, these stresses remain in the material as a residual stress upon unloading to zero stress from the tensile/compressive peak or intermediates stresses. The magnitude of these stresses vary depending on the point in the cycle from which it was unloaded from. When the material is re-loaded either in the same or reverse loading direction these residual stresses increase or decrease the effective stress acting in the material and as such the macroscopic yield stress of the material in subsequent cycle is changed significantly. The magnitude of intergranular stresses in many differently oriented grain families can be measured simultaneously using time of flight (ToF) neutron diffraction technique. In this paper, we have used this technique to experimentally study, how these intergranular stresses affect the yield (proof) stress of 316H at room temperature. (author)

  18. Uprooting and burial of invasive alien plants

    DEFF Research Database (Denmark)

    Kollmann, Johannes Christian; Brink-Jensen, Kasper; Frandsen, Sally I.

    2011-01-01

    Invasive alien plants are a problem for conservation management, and control of these species can be combined with habitat restoration. Subsoil burial of uprooted plants is a new method of mechanical control, which might be suitable in disturbed habitats. The method was tested in Rosa rugosa...

  19. 77 FR 4676 - Parents Eligible for Burial

    Science.gov (United States)

    2012-01-31

    ... available space, and has no spouse or child who is buried, or surviving spouse or child who, upon death, may... death has no spouse or child who is buried, or surviving spouse or child who, upon death, may be... provides burial eligibility to those parents whose unmarried veteran son or daughter dies due to combat or...

  20. Heat index and adjusted temperature as surrogates for wet bulb globe temperature to screen for occupational heat stress.

    Science.gov (United States)

    Bernard, Thomas E; Iheanacho, Ivory

    2015-01-01

    Ambient temperature and relative humidity are readily ava-ilable and thus tempting metrics for heat stress assessment. Two methods of using air temperature and relative humidity to create an index are Heat Index and Adjusted Temperature. The purposes of this article are: (1) to examine how well Heat Index and Adjusted Temperature estimated the wet bulb globe temperature (WBGT) index, and (2) to suggest how Heat Index and Adjusted Temperature can be used to screen for heat stress level. Psychrometric relationships were used to estimate values of actual WBGT for conditions of air temperature, relative humidity, and radiant heat at an air speed of 0.5 m/s. A relationship between Heat Index [°F] and WBGT [°C] was described by WBGT = -0.0034 HI(2) + 0.96 HI - 34. At lower Heat Index values, the equation estimated WBGTs that were ± 2 °C-WBGT around the actual value, and to about ± 0.5 °C-WBGT for Heat Index values > 100 °F. A relationship between Adjusted Temperature [°F] and WBGT [°C] was described by WBGT = 0.45 Tadj - 16. The actual WBGT was between 1 °C-WBGT below the estimated value and 1.4 °C-WBGT above. That is, there was a slight bias toward overestimating WBGT from Adjusted Temperature. Heat stress screening tables were constructed for metabolic rates of 180, 300, and 450 W. The screening decisions were divided into four categories: (1) exposure limit at rest. The authors do not recommend using Heat Index or Adjusted Temperature instead of WBGT, but they may be used to screen for circumstances when a more detailed analysis using WBGT is appropriate. A particular weakness is accounting for radiant heat; and neither air speed nor clothing was considered.

  1. The Management of Risk by Burial Societies in South Africa ...

    African Journals Online (AJOL)

    It considers members\\' perceptions of the risks faced by the burial societies themselves. It explores the ways in which burial societies develop community and establish trust. It investigates the procedures that have been developed by burial societies, on the basis of the trust so established, for the management of their risks.

  2. Temperature and strain-rate dependence of the flow stress of ultrapure tantalum single crystals

    International Nuclear Information System (INIS)

    Werner, M.

    1987-01-01

    Measurements of the temperature dependence of the cyclic flow stress of ultrapure tantalum single crystals (RRR >∼ 14000) are extended to lower temperatures. After cyclic deformation well into saturation at 400 K, the temperature dependence of the flow stress is measured between 80 and 450 K at five different plastic resolved shear-strain rates, ε pl , in the range 2 x 10 -5 to 6 x 10 -3 s -1 . Below a critical temperature T k the flow stress is dominantly controlled by the mobility of screw dislocations. A recent theory of Seeger describes the 'thermal' component, σ*, of the flow stress (resolved shear stress) in the temperature and stress regime where the strain rate is determined by the formation and migration of kink pairs. The analytical expressions are valid in well-defined ranges of stress and temperature. The evaluation of the experimental data yields a value for the formation enthalpy of two isolated kinks 2H k = 0.98 eV. From the low-stress (σ* k = 2.0 x 10 -6 m 2 s -1 . The product of the density of mobile screw dislocations and the distance between insurmountable obstacles is found to be 2 x 10 -5 m -1 . The stress dependence of the kink-pair formation enthalpy H kp follows the theoretically predicted curve in the elastic-interaction stress regime. At the transition to the line-tension approximation (near σ* ∼ 80 MPa) the activation volume increases rather abruptly. Moreover, the quantitative analysis involves kinks other than those of minimum height. The most likely candidates are kinks on {211} planes. (author)

  3. Effects of temperature and water stresses on germination of some ...

    African Journals Online (AJOL)

    Insaf

    2013-04-24

    Apr 24, 2013 ... species. Acta Oecol. 23:23-30. Singh F, Diwakar B (1995). Chickpea botany and production practices. Skill Development Series N°16. ICRISAT. Smita KJ, Nayyar H (2005). Carbendazim alleviates effects of water stress on chickpea seedlings. Biol. Plant. 49:289-291. Tejera NA, Soussi M, Lluch C (2006).

  4. Body Temperature Versus Microclimate Selection in Heat Stressed Dairy Cows

    Science.gov (United States)

    The purpose of this study is to characterize the thermoregulatory responses of unrestrained heat-stressed dairy cows within a freestall environment using fan and spray configurations for cooling cows while lying or standing. An experimental treatment sprayed individual cows lying in freestalls from ...

  5. Analytical model of transient temperature and thermal stress in ...

    Indian Academy of Sciences (India)

    failure stress) and to suitably choose a crystal that achieves this task. The result of this work is compared with a well-verified finite element solution and a good agreement has been found. Some conclusions are obtained: Tm:YAP crystal, which has high thermal conductivity, low expansion coefficient, low absorption ...

  6. Effect of stress-induced grain growth during room temperature ...

    Indian Academy of Sciences (India)

    The TEM observations reveal that stress-induced grain growth during tensile deformation is significantly suppressed for the nc Ni–Co alloys rich in Co in sharp contrast to those poor in Co. We believe that sufficient solutes could effectively pin grain boundaries making grain boundary motions (e.g. grain boundary migration ...

  7. Effects of temperature and water stresses on germination of some ...

    African Journals Online (AJOL)

    Chickpea production did not progress, in spite, of intensification of agricultural practices. Drought and thermal stresses were the major factors that decreased yield when the crop is generally sown in spring. Nevertheless, winter sowing has opened new opportunities for increasing chickpea production in arid areas.

  8. Paleomagnetic dating of burial diagenesis in Mississippian carbonates, Utah

    Science.gov (United States)

    Blumstein, Angela M.; Elmore, R. Douglas; Engel, Michael H.; Elliot, Crawford; Basu, Ankan

    2004-04-01

    The objective of this study is to test models for the origin of widespread secondary magnetizations in the Mississippian Deseret Limestone. The Delle Phosphatic Member of the Deseret Limestone is a source rock for hydrocarbons, and modeling studies indicate that it entered the oil window in the Early Cretaceous during the Sevier orogeny. Paleomagnetic and rock magnetic results from the Deseret Limestone and the stratigraphically equivalent Chainman Shale in central and western Utah indicate that the units contain two ancient magnetizations residing in magnetite. Burial temperatures are too low for the magnetizations to be thermoviscous in origin, and they are interpreted to be chemical remanent magnetizations (CRMs). Fold tests from western Utah indicate the presence of a prefolding Triassic to Jurassic CRM. Geochemical (87Sr/86Sr, δ13C, and δ18O) and petrographic analyses suggest that externally derived fluids did not alter these rocks. This CRM was acquired at the beginning of the oil window and is interpreted to be the result of burial diagenesis of organic matter. A second younger CRM in western central Utah is apparently postfolding and is probably Late Cretaceous to early Tertiary in age. On the basis of the thermal modeling, the timing overlaps with the oil window. These results are consistent with a connection between organic matter maturation and remagnetization. Modeling of the smectite-to-illite transformation in the Deseret Limestone suggests a mean age prior to acquisition of both CRMs, although the range for illitization overlaps with the Triassic to Jurassic CRM. The results of this study support the hypothesis that pervasive CRMs can be related to burial diagenetic processes. In addition, paleomagnetism can be used to determine the timing of such processes, which can benefit hydrocarbon exploration efforts.

  9. Stresses and strains in pavement structures due to the effect of temperatures

    Directory of Open Access Journals (Sweden)

    Svilar Mila

    2016-01-01

    Full Text Available At its absolute amount, stresses due to the effect of temperature in the pavement structures, especially those rigid, are often of the same order of magnitude as those resulting from vehicles' load, but it happens that due to such impact many slabs become cracked before the road is handed over into operation. The temperature stresses which occur in pavement structures include stresses due to bending and buckling, stresses due to friction and hidden stresses. Stresses caused by the influence of temperature in the pavement structure during the day are generally below the strength of the component materials so they do not cause the consequences for structure. However, appearance of residual stresses and their accumulation after a sufficiently long period of time may lead to failure in structure, i.e. thermal fatigue. The paper presents the effects of temperature changes on the pavement structures in the physical and mechanical terms, and the manner in which the temperature is taken into account during the design of pavement structures.

  10. Effects of transverse temperature field nonuniformity on stress in silicon sheet growth

    Science.gov (United States)

    Mataga, P. A.; Hutchinson, J. W.; Chalmers, B.; Bell, R. O.; Kalejs, J. P.

    1987-01-01

    Stress and strain rate distributions are calculated using finite element analysis for steady-state growth of thin silicon sheet temperature nonuniformities imposed in the transverse (sheet width) dimension. Significant reductions in residual stress are predicted to occur for the case where the sheet edge is cooled relative to its center provided plastic deformation with high creep rates is present.

  11. Temperature-stress phase diagram of strain glass Ti48.5Ni51.5

    International Nuclear Information System (INIS)

    Wang, Y.; Ren, X.; Otsuka, K.; Saxena, A.

    2008-01-01

    The temperature and stress dependence of the properties of a recently discovered strain glass Ti 48.5 Ni 51.5 , which is a glass of frozen local lattice strains, was investigated systematically. It was found that the ideal freezing temperature (T 0 ) of the strain glass decreases with increasing stress. When the stress exceeds a critical value σ c (T), the pseudo-B2 strain glass transforms into B19' martensite. However, the stress-strain behavior associated with such a stress-induced transition showed a crossover at a crossover temperature T CR , which is ∼20 K below T 0 . Above T CR , the sample showed superelastic behavior; however, below T CR , the sample demonstrated plastic behavior. More interestingly, the σ c vs. temperature relation for unfrozen strain glass obeys the Clausius-Clapyeron relationship, whereas that for frozen strain glass disobeys this universal thermodynamic law. A phenomenological explanation is provided for all the phenomena observed, and it is shown that all the anomalous effects come from the broken ergodicity of the glass system and a temperature-dependent relative stability of the martensitic phase. Based on experimental observations, a temperature-stress phase diagram is constructed for this strain glass, which may serve as a guide map for understanding and predicting the properties of strain glass

  12. Winter soil warming exacerbates the impacts of spring low temperature stress on wheat

    DEFF Research Database (Denmark)

    Li, Xiangnan; Jiang, D.; Liu, Fulai

    2016-01-01

    The increase in global mean air temperature is likely to affect the soil temperatures in agricultural areas. This study aims to study the effects of winter soil warming on the responses of wheat to low temperature stress in spring. Wheat plants were grown under either normal or increased soil...... temperature by 2.5 °C for 82 days in winter. The physiological and yield responses of the plants to a 2-day low temperature stress (4/2 °C in the day/night) at jointing stage were investigated. After exposing to low spring temperature, the plants that had experienced winter soil warming showed lower leaf...... and root water potential, lower oxygen scavenging capacity and poor photosynthetic performance as compared with the plants grown under normal soil temperature during winter. WL plants had significantly lower sugar content in shoot than the CL plants, which might have contributed to their higher...

  13. Thermomagnetic effect with two temperature theory for photothermal process under hydrostatic initial stress

    Directory of Open Access Journals (Sweden)

    Kh. Lotfy

    Full Text Available A novel technique is used to investigate the influence of magnetic field for a two dimensional deformations on a two temperature problem at the free surface of a semi-infinite medium. The investigation is carried out under the effects of both mechanical force and hydrostatic initial stress during a photothermal excitation theory. The equations of elastic waves, heat conduction equation, quasi-static electric field, carrier density, two temperature coefficient, ratios, and constitutive relationships for the thermo-magnetic-electric medium are obtained using the Harmonic Wave Method (HWM technique. The effects of thermoelastic, thermoelectric and two temperature parameters of the applied force on the displacement component, force stress, carrier density and temperature distribution has been depicted graphically. Keywords: Photothermal theory, Initial stress, Magnetic field, The harmonic wave, Two temperature

  14. Life assessments of elevated temperature components containing stress concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Zarrabi, K.; Hosseini-Toudeshky, H. [Univ. of New South Wales, Sydney, New South Wales (Australia). School of Mechanical and Manufacturing Engineering

    1995-12-31

    By and large the majority of cracking or failures that are related to the pressure components operating within the creep range occur at a stress concentration region such as a nozzle-vessel connection. Because of the geometrical constraint, the creep damage at a stress concentration region will be accumulated over a small region of the component and the material is said to behave in a creep-brittle manner. A relatively simple but approximate method (UNSW-LIFE2) has been devised at the University of New South Wales in Australia for creep life estimation of the pressure components that contain a stress concentrator. The principle of the UNSW-LIFE2 method has already been reported (Zarrabi et al 1994) but for completeness it is summarized in this paper as well. The objective of this paper is to describe the recent improvements to the UNSW-LIFE2 method and the finite element analysis that has been performed to verify the method.

  15. Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions.

    Science.gov (United States)

    Seo, Yongsuk; DiLeo, Travis; Powell, Jeffrey B; Kim, Jung-Hyun; Roberge, Raymond J; Coca, Aitor

    2016-08-01

    Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel. The purpose of this study is to compare estimated core body temperature (Tco-est), determined by heart rate (HR) data from a wearable chest strap physiology monitor, to standard rectal thermometry (Tre) under different conditions.  Tco-est and Tre measurements were obtained in thermoneutral and heat stress conditions (high temperature and relative humidity) during four different experiments including treadmill exercise, cycling exercise, passive heat stress, and treadmill exercise while wearing personal protective equipment (PPE).  Overall, the mean Tco-est did not differ significantly from Tre across the four conditions. During exercise at low-moderate work rates under heat stress conditions, Tco-est was consistently higher than Tre at all-time points. Tco-est underestimated temperature compared to Tre at rest in heat stress conditions and at a low work rate under heat stress while wearing PPE. The mean differences between the two measurements ranged from -0.1 ± 0.4 to 0.3 ± 0.4°C and Tco-est correlated well with HR (r = 0.795 - 0.849) and mean body temperature (r = 0.637 - 0.861).  These results indicate that, the comparison of Tco-est to Tre may result in over- or underestimation which could possibly lead to heat-related illness during monitoring in certain conditions. Modifications to the current algorithm should be considered to address such issues.

  16. Stress corrosion cracking of nickel base alloys in high temperature water

    International Nuclear Information System (INIS)

    Speidel, M.O.; Magdoswki, R.

    1993-01-01

    The resistance of nickel base alloys against stress corrosion cracking in high temperature water has been evaluated by measuring the crack growth rates for specific material-environment combinations. For this purpose, fracture mechanics testing techniques have been applied. The materials tested include both, precipitation hardened and solid solution hardened nickel base alloys. The effect of stress intensity on the stress corrosion crack growth rates has been established by measuring complete crack growth curves. In many cases, the effect of stress intensity on the crack growth rate is very small and thus a plateau is observed in the crack growth rate versus stress intensity curves. However, there are clear exceptions to this rule in certain materials and these are pointed out in comparison with data from the literature. The effect of yield strength on stress corrosion crack growth rates has been studied in detail. It is shown how precipitation hardening and particularly how work hardening influence stress corrosion cracking

  17. Effects of high temperature stress at different development stages on soybean isoflavone and tocopherol concentrations.

    Science.gov (United States)

    Chennupati, Pratyusha; Seguin, Philippe; Liu, Wucheng

    2011-12-28

    Soybean contains a range of compounds with putative health benefits including isoflavones and tocopherols. A study was conducted to determine the effects on these compounds of high temperature stress imposed at specific development stages [i.e., none, pre-emergence, vegetative, early reproductive (R1-4), late-reproductive (R5-8), or all stages]. Two cultivars (AC Proteina and OAC Champion) were grown in growth chambers set at contrasting temperatures [i.e., stress conditions of 33/25 °C (day/night temperature) and control conditions of 23/15 °C] in order to generate these treatments. Isoflavone and tocopherol concentrations in mature seeds were determined using high-performance liquid chromatography. In both cultivars isoflavone response was greatest when stress occurred during the R5-8 stages and during all development stages, these treatments reducing total isoflavone concentration by an average of 85% compared to the control. Stress imposed at other stages also affected isoflavone concentration although the response was smaller. For example, stress during the vegetative stages reduced total isoflavones by 33% in OAC Champion. Stress imposed pre-emergence had an opposite effect increasing daidzein concentration by 24% in AC Proteina. Tocopherol concentrations were affected the most when stress was imposed during all stages of development, followed by stress restricted to stages R5-8; response to stress during other stages was limited. The specific response of tocopherols differed, α-tocopherol being increased by high temperature by as much as 752%, the reverse being observed for δ-tocopherol and γ-tocopherol. The present study demonstrates that while isoflavone and tocopherol concentrations in soybeans are affected the most by stress occurring during seed formation, concentrations can also be affected by stress occurring at other stages including stages as early as pre-emergence.

  18. An investigation of characteristics of thermal stress caused by fluid temperature fluctuation at a T-junction pipe

    International Nuclear Information System (INIS)

    Miyoshi, Koji; Nakamura, Akira; Utanohara, Yoichi

    2014-01-01

    Thermal fatigue cracking may initiate at a T-junction pipe where high and low temperature fluids flow in from different directions and mix. Thermal stress is caused by a temperature gradient in a structure and by its variation. It is possible to obtain stress distributions if the temperature distributions at the pipe inner surface are obtained by experiments. The wall temperature distributions at a T-junction pipe were measured by experiments. The thermal stress distributions were calculated using the experimental data. The circumferential and axial stress fluctuations were larger than the radial stress fluctuation range. The stress fluctuation at the position of the maximum stress fluctuation had 10sec period. The distribution of the stress fluctuation was similar to that of the temperature fluctuation. The large stress fluctuations were caused by the time variation of the heating region by the hot jet flow. (author)

  19. Analysis of the Residual Stresses in Helical Cylindrical Springs at High Temperature

    Directory of Open Access Journals (Sweden)

    H. Sun

    2015-01-01

    Full Text Available Creep is one of the basic properties of materials, its speed significantly depends on the temperature. Helical cylindrical springs are widely used in the elements of heating systems. This results in necessity of taking into account the effect of temperature on the stress-strain state of the spring. The object of research is a helical cylindrical spring used at high temperatures. Under this condition the spring state stability should be ensured.The paper studies relaxation of stress state and generation of residual stresses. Calculations are carried out in ABAQUS environment. The purpose of this work is to discuss the law of relaxation and residual stress in the spring.This paper describes the basic creep theories of helical cylindrical spring material. The calculation formulas of shear stress relaxation for a fixed compression ratio are obtained. Distribution and character of stress contour lines in the cross section of spring are presented. The stress relaxation – time relationships are discussed. The approximate formula for calculating relaxation shear stresses in the cross section of helical springs is obtained.The paper investigates creep ratio and law of residual stress variation in the cross-section of spring at 650℃. Computer simulation in ABAQUS environment was used. Research presents a finite element model of the spring creep in the cross-section.The paper conducts analysis of the stress changes for the creep under constant load. Under constant load stresses are quickly decreased in the around area of cross-section and are increased in the centre, i.e. the maximum and minimum stresses come close with time. Research work shows the possibility for using the approximate formula to calculate the relaxation shear stress in the cross section of spring and can provide a theoretical basis for predicting the service life of spring at high temperatures.In research relaxation processes of stress state are studied. Finite element model is cre

  20. Non-uniform temperature gradients and thermal stresses produced ...

    Indian Academy of Sciences (India)

    The thermo-physical property variations of the workpiece are negligible. • The workpiece material is homogeneous and isotropic. • The heat flux per unit area is uniform along the azimuthal direction. • The temperature, T , depends on r, φ and t, (T = T (r, φ, t)). In the hollow sphere (inner radius, Ri,≤ r ≤ outer radius, Ro, and ...

  1. Physiological stress and ethanol accumulation in tree stems and woody tissues at sublethal temperatures from fire

    Science.gov (United States)

    Rick G. Kelsey; Douglas J. Westlind

    2017-01-01

    The lethal temperature limit is 60 degrees Celsius (°C) for plant tissues, including trees, with lower temperatures causing heat stress. As fire injury increases on tree stems, there is an accompanying rise in tissue ethanol concentrations, physiologically linked to impaired mitochondrial oxidative phosphorylation energy production. We theorize that sublethal tissue...

  2. Temperature dependence of residual stress in TiC coated Mo

    International Nuclear Information System (INIS)

    Yoshizawa, I.; Fukutomi, M.; Kamada, K.

    1984-01-01

    The effects of fabrication temperature and heat treatment on the residual stress in TiC coated Mo have been studied by using X-ray diffractometry. TiC coatings on Mo single crystal substrates with (100) and (111) surfaces were carried out with the Activated Reactive Evaporation (ARE) method. It was found that all Mo substrates measured show tensile residual stresses, and their values decrease as the fabrication temperature increases from 300 to 700 0 C. On the other hand, TiC films measured showed compressive residual stresses, for both TiC/Mo(100) and TiC/Mo(111) specimens. These compressive stresses also decreased with increasing the fabrication temperature. The residual stresses measured were higher in TiC/Mo(100) than in TiC/Mo(111). It was found that the compressive stresses in as-grown TiC films change to the tensile stresses after annealing at 1700 0 C for 30 min. The preferred orientations of TiC films were observed to depend on the fabrication temperature. However, no epitaxial growth of TiC films was found as far as the present experiment was concerned. (orig.)

  3. Neural models on temperature regulation for cold-stressed animals

    Science.gov (United States)

    Horowitz, J. M.

    1975-01-01

    The present review evaluates several assumptions common to a variety of current models for thermoregulation in cold-stressed animals. Three areas covered by the models are discussed: signals to and from the central nervous system (CNS), portions of the CNS involved, and the arrangement of neurons within networks. Assumptions in each of these categories are considered. The evaluation of the models is based on the experimental foundations of the assumptions. Regions of the nervous system concerned here include the hypothalamus, the skin, the spinal cord, the hippocampus, and the septal area of the brain.

  4. Temperature factors effect on occurrence of stress corrosion cracking of main gas pipeline

    Science.gov (United States)

    Nazarova, M. N.; Akhmetov, R. R.; Krainov, S. A.

    2017-10-01

    The purpose of the article is to analyze and compare the data in order to contribute to the formation of an objective opinion on the issue of the growth of stress corrosion defects of the main gas pipeline. According to available data, a histogram of the dependence of defects due to stress corrosion on the distance from the compressor station was constructed, and graphs of the dependence of the accident density due to stress corrosion in the winter and summer were also plotted. Data on activation energy were collected and analyzed in which occurrence of stress corrosion is most likely constructed, a plot of activation energy versus temperature is plotted, and the process of occurrence of stress corrosion by the example of two different grades of steels under the action of different temperatures was analyzed.

  5. Transient thermal stresses in multiple connected region exhibiting temperature dependence of material properties

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Maekawa, Toshiya.

    1983-01-01

    The examples of the analysis of thermal stress in multiple connection regions such as heat exchangers, nuclear reactor cores, ingot cases and polygonal region with elliptic holes are not few, but the temperature dependence of material constants was neglected in these researches because of the difficulty of analysis though the industrial problems related to thermal stress are apt to occur in the condition of relatively large temperature gradient. Also, the analysis of heat conduction problems taking the temperature dependence of material constants into account was limited to one-dimensional problems for which Kirchhoff's transmission can be used. The purpose of this study is to derive the equation of condition which assures the one-value property of rotation and displacement, taking the temperature dependence of material constants into account, and to complete the formulation of the plane thermal stress problems in multiple connection regions by stress function method. Also the method of numerical analysis using difference method is shown to examine the effectiveness of various formulated equations and the effect of the temperature dependence of material constants on temperature and thermal stress. The example of numerical calculation on a thin rectangular plate with a rectangular hole is shown. (Kako, I.)

  6. Variation in the immune state of Gammarus pulex (Crustacea, Amphipoda) according to temperature: Are extreme temperatures a stress?

    Science.gov (United States)

    Labaude, Sophie; Moret, Yannick; Cézilly, Frank; Reuland, Charel; Rigaud, Thierry

    2017-11-01

    Temperature is known to impact host-parasite interactions in various ways. Such effects are often regarded as the consequence of the increased metabolism of parasites with increasing temperature. However, the effect of temperature on hosts' immune system could also be a determinant. Here we assessed the influence of temperature on the immunocompetence of the crustacean amphipod Gammarus pulex. Amphipods play a key ecological role in freshwater ecosystems that can be altered by several parasites. We investigated the consequences of three weeks of acclimatization at four temperatures (from 9 °C to 17 °C) on different immunological parameters. Temperature influenced both hemocyte concentration and active phenoloxidase enzymatic activity, with lower values at intermediate temperatures, while total phenoloxidase activity was not affected. In addition, the ability of gammarids to clear a bacterial infection was at the highest at intermediate temperatures. These results suggest a dysregulation of the immune system of gammarids in response to stress induced by extreme temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Physiological and biochemical response to high temperature stress in Okra (Abelmoschus esculentus L. Moench)

    Science.gov (United States)

    Hayamanesh, Shahnoosh; Keitel, Claudia; Ahmad, Nabil; Trethowan, Richard

    2016-04-01

    High temperature has been shown to lower the growth and yield of Okra, an important summer vegetable crop grown in Asia, Africa, the Middle East and Australia. We aimed to characterise the physiological and biochemical response of Okra to heat stress. 150 genotypes from Pakistan and the AVRDC (The World Vegetable Centre) were screened for their physiological response (fluorescence, electrolyte leakage and yield) to heat in a greenhouse. Four genotypes (including heat tolerant and sensitive) were selected and subsequently grown in control and hot greenhouses. Daytime temperatures were on average 10°C warmer in the hot greenhouse, whereas nighttime temperatures were similar between the two temperature treatments. During a 12 week period, the physiological (assimilation rate, transpiration rate, stomatal conductance, fluorescence, electrolyte leakage, water potential) and biochemical (carbohydrates, sugar alcohols, C content) response of the four genotypes to heat stress was assessed. The effect of heat stress on the C allocation patterns and yield in Okra will be discussed.

  8. Effects of temperature and hypoxic stress on the oxygen ...

    African Journals Online (AJOL)

    The specific oxygen consumption rate (VO2lMb) of Labeo capensis, the freshwater mudsucker, was determined for small and large fish at winter (8°C) and summer (23°C) temperatures. VO2lMb was also determined during hypoxic conditions of the experimental water. It was found that VO2lMb does not differ substantially ...

  9. Microbial adhesion capacity. Influence of shear and temperature stress.

    Science.gov (United States)

    Fink, Rok; Oder, Martina; Rangus, Dušan; Raspor, Peter; Bohinc, Klemen

    2015-01-01

    Environmental parameters dictate the conditions for both biofilm formation and deconstruction. The aim of this study is to analyse the impact of hydrodynamic and thermodynamic effects on bacterial detachment. Escherichia coli grown on two stainless steel metal surfaces with different roughness (brushed with roughness of 0.05 μm and electropolished with roughness of 0.29 μm) are exposed to laminar and turbulent (shower) flows of phosphate buffered saline media at temperatures of 8, 20 and 37 °C. Results show that the turbulent flow removes significantly more bacterial cells than laminar flow (p materials. This indicates that the shear force determines the rate of detached bacteria. It is also observed that detachment of cells is more efficient on brushed than on electropolished contact surfaces because on the latter surface, fewer cells were attached before exposure. Moreover, we demonstrate that the temperature of the washing agent has an impact on bacterial detachment. At the same flow conditions, the exposure to higher temperature results in greater detachment rate.

  10. Transcriptional Profiling of Hydrogen Production Metabolism of Rhodobacter capsulatus under Temperature Stress by Microarray Analysis

    Directory of Open Access Journals (Sweden)

    Muazzez Gürgan

    2015-06-01

    Full Text Available Biohydrogen is a clean and renewable form of hydrogen, which can be produced by photosynthetic bacteria in outdoor large-scale photobioreactors using sunlight. In this study, the transcriptional response of Rhodobacter capsulatus to cold (4 °C and heat (42 °C stress was studied using microarrays. Bacteria were grown in 30/2 acetate/glutamate medium at 30 °C for 48 h under continuous illumination. Then, cold and heat stresses were applied for two and six hours. Growth and hydrogen production were impaired under both stress conditions. Microarray chips for R. capsulatus were custom designed by Affymetrix (GeneChip®. TR_RCH2a520699F. The numbers of significantly changed genes were 328 and 293 out of 3685 genes under cold and heat stress, respectively. Our results indicate that temperature stress greatly affects the hydrogen production metabolisms of R. capsulatus. Specifically, the expression of genes that participate in nitrogen metabolism, photosynthesis and the electron transport system were induced by cold stress, while decreased by heat stress. Heat stress also resulted in down regulation of genes related to cell envelope, transporter and binding proteins. Transcriptome analysis and physiological results were consistent with each other. The results presented here may aid clarification of the genetic mechanisms for hydrogen production in purple non-sulfur (PNS bacteria under temperature stress.

  11. The disappearance of European smiths' burials

    Czech Academy of Sciences Publication Activity Database

    Ježek, Martin

    2015-01-01

    Roč. 25, č. 1 (2015), s. 121-143 ISSN 0959-7743 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M300021203 Institutional support: RVO:67985912 Keywords : elite * burial * forging tools * symbolic * ritual * prehistory * Early Middle Ages * Marxism-Leninism Subject RIV: AC - Archeology, Anthropology, Ethnology

  12. Strain rate, temperature and representative length scale influence on plasticity and yield stress in copper

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Virginie [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2011-01-18

    Shock compression of materials constitutes a complex process involving high strain rates, elevated temperatures and compression of the lattice. Materials properties are greatly affected by temperature, the representative length scale and the strain rate of the deformation. Experimentally, it is difficult to study the dynamic microscopic mechanisms that affect materials properties following high intensity shock loading, but they can be investigated using molecular dynamics (MD) simulations. Moreover, MD allows a better control over some parameters. We are using MD simulations to study the effect of the strain rate, representative length scale and temperature on the properties of metals during compression. A half-million-atom Cu sample is subjected to strain rates ranging from 10{sup 7} s{sup -1} to 10{sup 12} s{sup -1} at different temperatures ranging from 50K to 1500K. Single crystals as well as polycrystals are investigated. Plasticity mechanisms as well as the evolution of the micro- and macro-yield stress are observed. Our results show that the yield stress increases with increasing strain rate and decreasing temperature. We also show that the strain rate at which the transition between constant and increasing yield stress as a function of the temperature occurs increases with increasing temperature. Calculations at different grain sizes will give an insight into the grain size effect on the plasticity mechanisms and the yield stress.

  13. Temperature and Oxidative Stress as Triggers for Virulence Gene Expression in Pathogenic Leptospira spp.

    Directory of Open Access Journals (Sweden)

    Tricia Fraser

    2017-05-01

    Full Text Available Leptospirosis is a zooanthroponosis aetiologically caused by pathogenic bacteria belonging to the genus, Leptospira. Environmental signals such as increases in temperatures or oxidative stress can trigger response regulatory modes of virulence genes during infection. This study sought to determine the effect of temperature and oxidative stress on virulence associated genes in highly passaged Leptospira borgpeterseneii Jules and L. interrogans Portlandvere. Bacteria were grown in EMJH at 30°C, 37°C, or at 30°C before being transferred to 37°C. A total of 14 virulence-associated genes (fliY, invA, lenA, ligB, lipL32, lipL36, lipL41, lipL45, loa22, lsa21, mce, ompL1, sph2, and tlyC were assessed using endpoint PCR. Transcriptional analyses of lenA, lipL32, lipL41, loa22, sph2 were assessed by quantitative real-time RT-PCR at the temperature conditions. To assess oxidative stress, bacteria were exposed to H2O2 for 30 and 60 min with or without the temperature stress. All genes except ligB (for Portlandvere and ligB and mce (for Jules were detectable in the strains. Quantitatively, temperature stress resulted in significant changes in gene expression within species or between species. Temperature changes were more influential in gene expression for Jules, particularly at 30°C and upshift conditions; at 37°C, expression levels were higher for Portlandvere. However, compared to Jules, where temperature was influential in two of five genes, temperature was an essential element in four of five genes in Portlandvere exposed to oxidative stress. At both low and high oxidative stress levels, the interplay between genetic predisposition (larger genome size and temperature was biased towards Portlandvere particularly at 30°C and upshift conditions. While it is clear that expression of many virulence genes in highly passaged strains of Leptospira are attenuated or lost, genetic predisposition, changes in growth temperature and/or oxidative intensity and

  14. Fundamental studies of stress distributions and stress relaxation in oxide scales on high temperature alloys. [Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    Shores, D.A.; Stout, J.H.; Gerberich, W.W.

    1993-06-01

    This report summarizes a three-year study of stresses arising in the oxide scale and underlying metal during high temperature oxidation and of scale cracking. In-situ XRD was developed to measure strains during oxidation over 1000{degrees}C on pure metals. Acoustic emission was used to observe scale fracture during isothermal oxidation and cooling, and statistical analysis was used to infer mechanical aspects of cracking. A microscratch technique was used to measure the fracture toughness of scale/metal interface. A theoretical model was evaluated for the development and relaxation of stresses in scale and metal substrate during oxidation.

  15. Point stresses during reproductive stage rather than warming seasonal temperature determine yield in temperate rice.

    Science.gov (United States)

    Espe, Matthew B; Hill, Jim E; Hijmans, Robert J; McKenzie, Kent; Mutters, Randall; Espino, Luis A; Leinfelder-Miles, Michelle; van Kessel, Chris; Linquist, Bruce A

    2017-10-01

    Climate change is predicted to shift temperature regimes in most agricultural areas with temperature changes expected to impact yields of most crops, including rice. These temperature-driven effects can be classified into point stresses, where a temperature event during a sensitive stage drives a reduction in yield, or seasonal warming losses, where raised temperature is thought to increase maintenance energy demands and thereby decrease available resources for yield formation. Simultaneous estimation of the magnitude of each temperature effect on yield has not been well documented due to the inherent difficulty in separating their effects. We simultaneously quantified the magnitude of each effect for a temperate rice production system using a large data set covering multiple locations with data collected from 1995 to 2015, combined with a unique probability-based modeling approach. Point stresses, primarily cold stress during the reproductive stages (booting and flowering), were found to have the largest impact on yield (over 3 Mg/ha estimated yield losses). Contrary to previous reports, yield losses caused by increased temperatures, both seasonal and during grain-filling, were found to be small (approximately 1-2% loss per °C). Occurrences of cool temperature events during reproductive stages were found to be persistent over the study period, and within season, the likelihood of a cool temperature event increased when flowering occurred later in the season. Short and medium grain types, typically recommended for cool regions, were found to be more tolerant of cool temperatures but more sensitive to heat compared to long grain cultivars. These results suggest that for temperate rice systems, the occurrence of periodic stress events may currently overshadow the impacts of general warming temperature on crop production. © 2017 John Wiley & Sons Ltd.

  16. Temperature-dependent polymerization shrinkage stress kinetics of resin-composites.

    Science.gov (United States)

    Watts, D C; Alnazzawi, A

    2014-06-01

    To determine temperature dependence of shrinkage stress kinetics for a set of resin composites formulated with dimethacrylate monomer matrices. Six representative resin composites with a range of resin matrices were selected. Two of them were considered as low shrinking resin composites: Kalore and Venus Diamond. The shrinkage stress kinetics at 23°C and 37°C were measured continuously using a Bioman instrument for 60min. Stress levels between materials were compared at two intervals: 2min and 60min. Specimen temperatures were controlled by a newly designed heating device. Stress measurements were monitored for 1h, after irradiation for 40s at 550mW/cm(2) (energy density=22J/cm(2)). Three specimens (n=3) were used at each temperature per material. Shrinkage stress at 23°C ranged from 2.93MPa to 4.71MPa and from 3.57MPa to 5.42MPa for 2min and 60min after photo-activation, respectively. The lowest stress-rates were recorded for Kalore and Venus Diamond (0.34MPas(-1)), whereas the highest was recorded for Filtek Supreme XTE (0.63MPas(-1)). At 37°C, shrinkage stress ranged from 3.27MPa to 5.35MPa and from 3.36MPa to 5.49MPa for 2min and 60min after photo-activation, respectively. Kalore had the lowest stress-rate (0.44MPas(-1)), whereas Filtek Supreme XTE had the highest (0.85MPas(-1)). Materials exhibited a higher stress at 37°C than 23°C except for Kalore and Venus Diamond. Positive correlations were found between shrinkage stress and stress-rate at 23°C and 37°C (r=0.70 and 0.92, respectively). Resin-composites polymerized at elevated temperature (37°C) completed stress build up more rapidly than specimens held at 23°C. Two composites exhibited atypical reduced stress magnitudes at the higher temperature. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Numerical simulations on the temperature gradient and thermal stress of a thermoelectric power generator

    International Nuclear Information System (INIS)

    Wu, Yongjia; Ming, Tingzhen; Li, Xiaohua; Pan, Tao; Peng, Keyuan; Luo, Xiaobing

    2014-01-01

    Highlights: • An appropriate ceramic plate thickness is effective in alleviating the thermal stress. • A smaller distance between thermo-pins can help prolong lifecycle of the TE module. • Either a thicker or a thinner copper conducting strip effectively reduces thermal stress. • A suitable tin soldering thickness will alleviate thermal stress intensity and increase thermal efficiency. - Abstract: Thermoelectric generator is a device taking advantage of the temperature difference in thermoelectric material to generate electric power, where the higher the temperature difference of the hot-cold ends, the higher the efficiency will be. However, higher temperature or higher heat flux upon the hot end will cause strong thermal stress which will negatively influence the lifecycle of the thermoelectric module. This phenomenon is very common in industrial applications but seldom has research work been reported. In this paper, numerical analysis on the thermodynamics and thermal stress performance of the thermoelectric module has been performed, considering the variation on the thickness of materials; the influence of high heat flux on thermal efficiency, power output, and thermal stress has been examined. It is found that under high heat flux imposing upon the hot end, the thermal stress is so strong that it has a decisive effect on the life expectation of the device. To improve the module’s working condition, different geometrical configurations are tested and the optimum sizes are achieved. Besides, the side effects on the efficiency, power output, and open circuit voltage output of the thermoelectric module are taken into consideration

  18. Experimental study on critical breaking stress of float glass under elevated temperature

    International Nuclear Information System (INIS)

    Wang, Yu; Wang, Qingsong; Shao, Guangzheng; Chen, Haodong; Sun, Jinhua; He, Linghui; Liew, K.M.

    2014-01-01

    Highlights: • Critical breaking stresses of clear, ground and coated glass were measured. • Breaking stress and strain of smooth glass were measured from 25 °C to 400 °C. • At approximately 100 °C, critical stress reached the minimum value. • Surface treatment and ambient temperature have notable effects on glass breaking. - Abstract: Cracking and subsequent fallout of glass may significantly affect fire dynamics in compartments. Moreover, the breaking tensile stress of glass, a crucial parameter for breakage occurrence, is the least well known among mechanical properties. In this work, a series of experiments were conducted, through mechanical tensile tests, to directly measure the breaking stress of float glass using Material Testing System 810 apparatus. Clear, ground and coated glass samples with a thickness of 6 mm were measured under ambient conditions, with a room temperature of 25 °C. The breaking stress of smooth glass samples was also measured at 75 °C, 100 °C, 125 °C, 150 °C, 200 °C, 300 °C and 400 °C, respectively. The results show that surface treatment may decrease the critical tensile stress of glass panes. The average breaking stress also fluctuates considerably, from 26.60 to 35.72 MPa with the temperature variations investigated here. At approximately 100 °C, critical stress reached the minimum value at which glass breakage occurs more easily. In addition, the thermal expansion coefficient was established using a thermal dilatometer, to obtain the maximum temperature difference float glass can withstand. It is intended that these results will provide some practical guidelines for fire safety engineers

  19. The Coral Reef Temperature Anomaly Database (CoRTAD) - Global, 4 km, Sea Surface Temperature and Related Thermal Stress Metrics for 1985-2005 (NODC Accession 0044419)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  20. Heat priming induces trans-generational tolerance to high temperature stress in wheat

    Directory of Open Access Journals (Sweden)

    Xiao eWang

    2016-04-01

    Full Text Available Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH, the progeny of heat-primed plants (PH possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1 which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production.

  1. Heat Priming Induces Trans-generational Tolerance to High Temperature Stress in Wheat.

    Science.gov (United States)

    Wang, Xiao; Xin, Caiyun; Cai, Jian; Zhou, Qin; Dai, Tingbo; Cao, Weixing; Jiang, Dong

    2016-01-01

    Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1) which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production.

  2. Deformation, Stress Relaxation, and Crystallization of Lithium Silicate Glass Fibers Below the Glass Transition Temperature

    Science.gov (United States)

    Ray, Chandra S.; Brow, Richard K.; Kim, Cheol W.; Reis, Signo T.

    2004-01-01

    The deformation and crystallization of Li(sub 2)O (center dot) 2SiO2 and Li(sub 2)O (center dot) 1.6SiO2 glass fibers subjected to a bending stress were measured as a function of time over the temperature range -50 to -150 C below the glass transition temperature (Tg). The glass fibers can be permanently deformed at temperatures about 100 C below T (sub)g, and they crystallize significantly at temperatures close to, but below T,, about 150 C lower than the onset temperature for crystallization for these glasses in the no-stress condition. The crystallization was found to occur only on the surface of the glass fibers with no detectable difference in the extent of crystallization in tensile and compressive stress regions. The relaxation mechanism for fiber deformation can be best described by a stretched exponential (Kohlrausch-Williams-Watt (KWW) approximation), rather than a single exponential model.The activation energy for stress relaxation, Es, for the glass fibers ranges between 175 and 195 kJ/mol, which is considerably smaller than the activation energy for viscous flow, E, (about 400 kJ/mol) near T, for these glasses at normal, stress-free condition. It is suspected that a viscosity relaxation mechanism could be responsible for permanent deformation and crystallization of the glass fibers below T,

  3. Polyamine accumulation in transgenic tomato enhances the tolerance to high temperature stress.

    Science.gov (United States)

    Cheng, Lin; Zou, Yijing; Ding, Shuli; Zhang, Jiajing; Yu, Xiaolin; Cao, Jiashu; Lu, Gang

    2009-05-01

    Polyamines play an important role in plant response to abiotic stress. S-adenosyl-l-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the tolerance of high-temperature stress in tomato, SAMDC cDNA isolated from Saccharomyces cerevisiae was introduced into tomato genome by means of Agrobacterium tumefaciens through leaf disc transformation. Transgene and expression was confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing yeast SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wild-type plants under high temperature stress, and enhanced antioxidant enzyme activity and the protection of membrane lipid peroxidation was also observed. This subsequently improved the efficiency of CO(2) assimilation and protected the plants from high temperature stress, which indicated that the transgenic tomato presented an enhanced tolerance to high temperature stress (38 degrees C) compared with wild-type plants. Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating high temperature-tolerant germplasm.

  4. Temporal thermometry fails to track body core temperature during heat stress.

    Science.gov (United States)

    Low, David A; Vu, Albert; Brown, Marilee; Davis, Scott L; Keller, David M; Levine, Benjamin D; Crandall, Craig G

    2007-07-01

    The aim of this study was to assess the accuracy of temporal scanning thermometry in monitoring internal temperature increases during passive heating. Sixteen subjects (5 males and 11 females) underwent a whole-body passive heat stress (water-perfused suit) to increase internal temperature. Temperatures were obtained with a temporal scanner and with an ingestible-pill telemetry system that tracks intestinal temperature. Temperatures were recorded while subjects were normothermic (34 degrees C water-perfusing suit) and every 10 min during passive heating (48 degrees C water-perfusing suit). Heart rate (ECG), mean skin temperature (weighted six-site average), skin blood flow (laser Doppler flowmetry), and sweat rate (capacitance hygrometry) were all significantly elevated at the end of heating (all P heat stress temporal-derived temperature was not different from intestinal temperature (36.98 +/- 0.09 vs 37.01 +/- 0.09 degrees C, respectively, P = 0.76). However, after 30 min of heating (the greatest duration of heating completed by all subjects), temporal-derived temperature decreased to below the pre-heat stress baseline (-0.22 +/- 0.11), whereas intestinal temperature increased by 0.39 +/- 0.07 degrees C (P heating (N = 11), intestinal-derived internal temperature increased by 0.70 +/- 0.09 degrees C, whereas temporal-derived temperature decreased by 0.29 +/- 0.10 degrees C (P heating. Given these findings, it is recommended that this technique not be used to assess temperature in hyperthermic diaphoretic subjects.

  5. The study on stress-strain state of the spring at high temperature using ABAQUS

    Directory of Open Access Journals (Sweden)

    H Sun

    2014-01-01

    Full Text Available Cylindrical helical springs are widely used in the elements of thermal energy devices. It is necessary to guarantee the stability of the stress state of spring in high temperature. Relaxation phenomenon of stress is studied in this paper. Calculations are carried out in the environment of ABAQUS. The verification is taken out using analytical calculations.This paper describes the distribution and character of stress contour lines on the cross section of spring under the condition of instantaneous load, explicates the relaxation law with time. Research object is cylindrical helical spring, that working at high temperature. The purpose of this work is to get the stress relaxation law of spring, and to guarantee the long-term strength.This article presents the basic theory of helical spring. Establishes spring mathematical model of creep under the loads of compression and torsion. The stress formulas of each component in the cross section of spring are given. The calculation process of relaxation is analyzed in the program ABAQUS.In this paper compare the analytical formulas of spring stress with the simulation results, which are created by program ABAQUS.Finite element model for stress creep analysis in the cross section is created, material of spring – stainless steel 10X18N9T, springs are used at the temperature 650℃.At the beginning, stress-stain of spring is in the elastic state. Analyzes the change law of creep stress under the condition of constant load and a fixed compression.When analyzing under the condition of a fixed compression, the stresses are quickly decreased in most area in the cross section of spring, and the point of minimum shear stress gradually moves to the direction of outer diameter, because of this, stresses in a small area near the center increase slowly at first then decrease gradually with time. When analyzing under the condition of constant load, the stresses are quickly decreased in the around area and in creased

  6. The stress corrosion resistance and the cryogenic temperature mechanical properties of annealed Nitronic 60 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    Ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of annealed, straightened, and centerless ground Nitronic 60 stainless steel alloy bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing strength with decreasing temperature to -196 C. Below liquid nitrogen temperature the smooth tensile and notched tensile strengths decreased slightly while the elongation and reduction of area decreased drastically. The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens and transverse C-ring specimens exposed to: alternate immersion in a 3.5% NaCl bath; humidity cabinet; and a 5% salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack. Approximately 3/4 of the transverse C-rings exposed to alternate immersion and to salt spray experienced a pitting attack on the top and bottom ends. Additional stress corrosion tests were performed on transverse tensile specimens. No failures occurred in the 90% stressed specimens exposed for 90 days in the alternate immersion and salt spray environments

  7. Growth and Yield Quality Parameter of Phyllanthus Amarus as Affected by Moisture and Temperature Stress factors

    Directory of Open Access Journals (Sweden)

    Chandrawanshi, N.

    2013-04-01

    Full Text Available This work investigates the influence of moisture and temperature stress on plant phenological parameters of Phyllanthus amarusplant. A pot experiment was conducted under controlled water stress environment in greenhouse during the Rabi season of 2007 and 2008 at the Experimental Farm area, JNKVV, Jabalpur. Plants were treated with different levels of water and temperature stresses. The experimental design was Completely Randomized Design (CRD with six treatments and five replications. Moisture stress has been given on selected dates for which the sets of pot were first brought to field capacity and the water with hold till wilting. It was found that the Plantheight, Root length, Number of leaves, Number of branches per plants, No. of fruits per plant, Leaf area, Dry weight gm per plant were found maximum in control condition.

  8. Estimates of chemical compaction and maximum burial depth from bedding parallel stylolites

    Science.gov (United States)

    Gasparrini, Marta; Beaudoin, Nicolas; Lacombe, Olivier; David, Marie-Eleonore; Youssef, Souhail; Koehn, Daniel

    2017-04-01

    Chemical compaction is a diagenetic process affecting sedimentary series during burial that develops rough dissolution surfaces named Bedding Parallel Stylolites (BPS). BPS are related to the dissolution of important rock volumes and can lead to porosity reduction around them due to post-dissolution cementation. Our understanding of the effect of chemical compaction on rock volume and porosity evolution during basin burial is however too tight yet to be fully taken into account in basin models and thermal or fluid-flow simulations. This contribution presents a novel and multidisciplinary approach to quantify chemical compaction and to estimate maximum paleodepth of burial, applied to the Dogger carbonate reservoirs from the Paris Basin sub-surface. This succession experienced a relatively simple burial history (nearly continuous burial from Upper Jurassic to Upper Cretaceous, followed by a main uplift phase), and mainly underwent normal overburden (inducing development of BPS), escaping major tectonic stress episodes. We considered one core from the depocentre and one from the eastern margin of the basin in the same stratigraphic interval (Bathonian Sup. - Callovian Inf.; restricted lagoonal setting), and analysed the macro- and micro-facies to distinguish five main depositional environments. Type and abundance of BPS were continuously recorded along the logs and treated statistically to obtain preliminary rules relying the occurrence of the BPS as a function of the contrasting facies and burial histories. The treatment of high resolution 2D images allowed the identification and separation of the BPS to evaluate total stylolitization density and insoluble thickness as an indirect measure of the dissolved volume, with respect to the morphology of the BPS considered. Based on the morphology of the BPS roughness, we used roughness signal analysis method to reconstruct the vertical paleo-stress (paleo-depth) recorded by the BPS during chemical compaction. The

  9. The effect of air velocity on heat stress at increased air temperature

    DEFF Research Database (Denmark)

    Bjerg, Bjarne Schmidt; Wang, Xiaoshuai; Zhang, Guoqiang

    Increased air velocity is a frequently used method to reduce heat stress of farm animals housed in warm conditions. The main reason why the method works is that higher air velocity increases the convective heat release from the animals. Convective heat release from the animals is strongly related...... to the temperature difference between the surfaces of animals and the surrounding air, and this temperature difference declines when the air temperature approaches the animal body temperature. Consequently it can it by expected that the effect of air velocity decreases at increased air temperature. The literature...... on farm animals in warm conditions includes several thermal indices which incorporate the effect of air velocities. But, surprisingly none of them predicts a decreased influence of air velocity when the air temperature approaches the animal body temperature. This study reviewed published investigations...

  10. Influence of peak oral temperatures on veneer–core interface stress state

    Directory of Open Access Journals (Sweden)

    Massimo Marrelli

    2015-01-01

    Full Text Available Objective: There is a growing interest for the use of Y-TZP zirconia as core material in veneered all-ceramic prostheses. The objective of this study was to evaluate the influence of CET on the stress distribution of a porcelain layered to zirconia core single crowns by finite elements analysis. Material and methods: CET of eight different porcelains was considered during the analysis. Results: Results of this study indicated that the mismatch in CET between the veneering porcelain and the Y-TZP zirconia core has to be minimum (0.5–1 μm/mK so as to decrease the growing of residual stresses which could bring chipping. Conclusions: The stress state due to temperature variation should be carefully taken into consideration while studying the effect of mechanical load on zirconia core crown by FEA. The interfacial stress state can be increased by temperature variation up to 20% with respect to the relative failure parameter (interface strength in this case. This means that stress due to mechanical load combined to temperature variation-induced stress can lead porcelain veneer–zirconia core interfaces to failure.

  11. Temperature Field Prediction for Determining the Residual Stresses Under Heat Treatment of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    A. V. Livshits

    2014-01-01

    Full Text Available The article is devoted to non-stationary temperature field blanks from aluminum alloys during heat treatment. It consists of the introduction and two smaller paragraphs. In the introduction the author concerns the influence of residual stresses arising in the manufacturing process of details, on the strength of the whole aircraft construction and, consequently, on their technical and economic parameters, such as weight, reliability, efficiency, and cost. He also notes that the residual stresses appeared during the production of parts change their location, size and direction under the influence of the elastic deformations that occur during the exploitation of aircraft. Redistributed residual stresses may have a chaotic distribution that may cause overlap of these stresses on the stresses caused by the impact of workload of constructions and destruction or damage of aircraft components.The first paragraph is devoted to the existing methods and techniques for determining the residual stresses. The presented methods and techniques are analyzed to show the advantages and disadvantages of each of them. The conclusion is drawn that the method to determine the residual stresses is necessary, its cost is less than those of existing ones, and an error does not exceed 10%.In the second section, the author divides the problem of determining the residual stresses into two parts, and describes the solution methods of the first one. The first problem is to define the temperature field of the work piece. The author uses a Fourier equation with the definition of initial and boundary conditions to describe a mathematical model of the heat cycle of work piece cooling. He draws special attention here to the fact that it is complicated to determine the heat transfer coefficient, which characterizes the process of cooling the work piece during hardening because of its dependence on a number of factors, such as changing temperature-dependent material properties of

  12. Elevated temperature design of KALIMER reactor internals accounting for creep and stress-rupture effects

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Yoo, Bong

    2000-01-01

    In most LMFBR (Liquid Metal Fast Breed Reactor) design, the operating temperature is very high and the time-dependent creep and stress-rupture effects become so important in reactor structural design. Therefore, unlike with conventional PWR, the normal operating conditions can be basically dominant design loading because the hold time at elevated temperature condition is so long and enough to result in severe total creep ratcheting strains during total service lifetime. In this paper, elevated temperature design of the conceptually designed baffle annulus regions of KALIMER (Korea Advanced Liquid Metal Reactor) reactor internal structures is carried out for normal operating conditions which have the operating temperature 530 deg. C and the total service lifetime of 30 years. For the elevated temperature design of reactor internal structures, the ASME Code Case N-201-4 is used. Using this code, the time-dependent stress limits, the accumulated total inelastic strain during service lifetime, and the creep-fatigue damages are evaluated with the calculation results by the elastic analysis under conservative assumptions. The application procedures of elevated temperature design of the reactor internal structures using ASME code case N-201-4 with the elastic analysis method are described step by step in detail. This paper will be useful guide for actual application of elevated temperature design of various reactor types accounting for creep and stress-rupture effects. (author)

  13. Low-temperature strain ageing in In-Pb alloys under stress relaxation conditions

    International Nuclear Information System (INIS)

    Fomenko, L.S.

    2000-01-01

    The dynamic strain ageing (DSA) of In-Pb (6 and 8 at. % Pb) substitutional solid solution single crystals is studied at temperatures 77-205 K under stress relaxation conditions. The dependences of the stress increment after relaxation connected with DSA on stress relaxation time, stress relaxation rate at the end of the relaxation, temperature, alloy content, flow stress, and strain are determined. It is shown that the DSA kinetic is described by a Harper-type equation with the exponent equal to 1/3 and a low activation energy value (0.3-0.34 eV). This provides a low temperature of the DSA onset (∼ 0.17 T m , where T m is the melt temperature) and is evidence of pipe-mode diffusion. It is supposed that the obstacles to dislocation motion in the crystals studied consist of the groups of solutes, and the strength of the obstacles increases during the DSA due to the pipe diffusion of the solute atoms along the dislocations

  14. Appropriate B indices for evaluating load-controlling stresses in piping products at elevated temperatures

    International Nuclear Information System (INIS)

    Rodabaugh, E.C.

    1977-01-01

    At the present time, rules for design of piping for nuclear power plant elevated temperature service are contained in Code Case 1592-8. A Task Group under the Code Working Group on Pipe Design has prepared a revised portion on piping for a future revision of Code Case 1592. This revised portion contains explicit equations for calculating stresses; those stresses are limited by the general stress limits of the Code Case. The stress equations involve the use of stress indices which, except for the B 2 ' indices, are given in the present Code, NB-3600. This report started as an effort to develop appropriate B 2 ' indices for inclusion on the Code Case. However, the report shows that the B 1 and B 2 indices are based on limit load concepts hence there is no need for the B 2 ' indices. The general concepts and motivation behind the stress index approach is described. The background of the B 1 and B 2 indices is given for the several types of piping products covered by the indices. This report is concerned with stress indices in equations as used for checking the equivalent of ''Primary Stress Intensity Limits.'' It does not address the use of stress indices and equations as used for ''Limits on Deformation-Controlled Quantities.''

  15. Prediction of creep of metallic materials under time-variable temperatures and stresses

    International Nuclear Information System (INIS)

    Batsoulas, N.D.

    1994-01-01

    A method is presented for the prediction of metallic materials creep behaviour at time-variable temperatures, exclusively with creep input data under constant loading. The method is derived from a more general physical-phenomenological model and, additionally, incorporates the prediction under time-variable stresses. To test the method's predicting capability, a series of experiments was carried out for the creep strain at time-variable temperatures and stresses for austenitic steel X8CrNiMoNb 16-16. The test data were predicted reasonably well using the method in question. (orig.) [de

  16. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    Science.gov (United States)

    Pechersky, Martin J.

    1999-01-01

    An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

  17. Transformation of Holes Emission Paths under Negative Bias Temperature Stress in Deeply Scaled pMOSFETs

    Directory of Open Access Journals (Sweden)

    Yiming Liao

    2015-01-01

    Full Text Available We examine the impact of negative bias temperature (NBT stress on the fluctuations in ID and IG for deeply scaled pMOSFETs and find that the relative high NBT stress triggers IG-RTN and ID-step. Through the analysis of the field dependence of emission constant and the carrier separation measurement, it is found that under the relative high NBT stress some traps keep charged state for very long time, as observing step-like behaviors in ID, while other traps emit charged holes to the gate side through TAT process, which originate both ID-step and ID-RTN.

  18. Overexpression of Arabidopsis P3B increases heat and low temperature stress tolerance in transgenic sweetpotato.

    Science.gov (United States)

    Ji, Chang Yoon; Jin, Rong; Xu, Zhen; Kim, Ho Soo; Lee, Chan-Ju; Kang, Le; Kim, So-Eun; Lee, Hyeong-Un; Lee, Joon Seol; Kang, Chang Ho; Chi, Yong Hun; Lee, Sang Yeol; Xie, Yiping; Li, Hongmin; Ma, Daifu; Kwak, Sang-Soo

    2017-08-14

    Sweetpotato (Ipomoea batatas [L.] Lam) is suitable for growth on marginal lands due to its abiotic stress tolerance. However, severe environmental conditions including low temperature pose a serious threat to the productivity and expanded cultivation of this crop. In this study, we aimed to develop sweetpotato plants with enhanced tolerance to temperature stress. P3 proteins are plant-specific ribosomal P-proteins that act as both protein and RNA chaperones to increase heat and cold stress tolerance in Arabidopsis. Here, we generated transgenic sweetpotato plants expressing the Arabidopsis ribosomal P3 (AtP3B) gene under the control of the CaMV 35S promoter (referred to as OP plants). Three OP lines (OP1, OP30, and OP32) were selected based on AtP3B transcript levels. The OP plants displayed greater heat tolerance and higher photosynthesis efficiency than wild type (WT) plants. The OP plants also exhibited enhanced low temperature tolerance, with higher photosynthesis efficiency and less membrane permeability than WT plants. In addition, OP plants had lower levels of hydrogen peroxide and higher activities of antioxidant enzymes such as peroxidase and catalase than WT plants under low temperature stress. The yields of tuberous roots and aerial parts of plants did not significantly differ between OP and WT plants under field cultivation. However, the tuberous roots of OP transgenic sweetpotato showed improved storage ability under low temperature conditions. The OP plants developed in this study exhibited increased tolerance to temperature stress and enhanced storage ability under low temperature compared to WT plants, suggesting that they could be used to enhance sustainable agriculture on marginal lands.

  19. Flux Balance Analysis of Escherichia coli under Temperature and pH Stress Conditions

    KAUST Repository

    Xu, Xiaopeng

    2015-05-12

    An interesting discovery in biology is that most genes in an organism are dispensable. That means these genes have minor effects on survival of the organism in standard laboratory conditions. One explanation of this discovery is that some genes play important roles in specific conditions and are essential genes under those conditions. E. coli is a model organism, which is widely used. It can adapt to many stress conditions, including temperature, pH, osmotic, antibiotic, etc. Underlying mechanisms and associated genes of each stress condition responses are usually different. In our analysis, we combined protein abundance data and mutant conditional fitness data into E. coli constraint-based metabolic models to study conditionally essential metabolic genes under temperature and pH stress conditions. Flux Balance Analysis was employed as the modeling method to analysis these data. We discovered lists of metabolic genes, which are E. coli dispensable genes, but conditionally essential under some stress conditions. Among these conditionally essential genes, atpA in low pH stress and nhaA in high pH stress found experimental evidences from previous studies. Our study provides new conditionally essential gene candidates for biologists to explore stress condition mechanisms.

  20. Effect of temperature on the permeability of gas adsorbed coal under triaxial stress conditions

    Science.gov (United States)

    Li, Xiangchen; Yan, Xiaopeng; Kang, Yili

    2018-04-01

    The combined effects of gas sorption, stress and temperature play a significant role in the changing behavior of gas permeability in coal seams. The effect of temperature on nitrogen and methane permeability of naturally fractured coal is investigated. Coal permeability, P-wave velocity and axial strain were simultaneously measured under two effective stresses and six different temperatures. The results showed that the behavior of nitrogen and methane permeability presented nonmonotonic changes with increasing temperature. The variation in the P-wave velocity and axial strain showed a good correspondence with coal permeability. A higher effective stress limited the bigger deformation and caused the small change in permeability. Methane adsorption and desorption significantly influence the mechanical properties of coal and play an important role in the variations in coal permeability. The result of coal permeability during a complete stress-strain process showed that the variation in permeability is determined by the evolution of the internal structure. The increase in the temperature of the gas saturated coal causes the complex interaction between matrix swelling, matrix shrinkage and micro-fracture generation, which leads to the complex changes in coal structure and permeability. These results are helpful to understand the gas transport mechanism for exploiting coal methane by heat injection.

  1. Cleanup Verification Package for the 118-F-2 Burial Ground

    International Nuclear Information System (INIS)

    Capron, J.M.; Anselm, K.A.

    2008-01-01

    This cleanup verification package documents completion of remedial action, sampling activities, and compliance with cleanup criteria for the 118-F-2 Burial Ground. This burial ground, formerly called Solid Waste Burial Ground No. 1, was the original solid waste disposal site for the 100-F Area. Eight trenches contained miscellaneous solid waste from the 105-F Reactor and one trench contained solid waste from the biology facilities

  2. Carbon and nitrogen metabolism in arbuscular mycorrhizal maize plants under low-temperature stress

    DEFF Research Database (Denmark)

    Zhu, Xian-Can; Song, Feng-Bin; Liu, Fulai

    2015-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 258C for 4 weeks...... plants were higher than those of non-AM plants. AM plants had a higher net photosynthetic rate (Pn) than non-AM plants, although low temperature inhibited the Pn. Compared with non-AM plants, AM plants exhibited higher leaf soluble sugars, reducing sugars, root sucrose and fructose contents, and sucrose...... phosphate synthase and amylase activities at low temperature. Moreover, low-temperature stress increased theC :Nratio in the leaves of maize plants, and AM colonisation decreased the root C :N ratio. These results suggested a difference in the C and N metabolism of maize plants at ambient and low...

  3. Elucidating stress proteins in rice (Oryza sativa L.) genotype under elevated temperature: a proteomic approach to understand heat stress response.

    Science.gov (United States)

    Kumar, Narendra; Suyal, Deep Chandra; Sharma, Ishwar Prakash; Verma, Amit; Singh, Hukum

    2017-07-01

    Rice is one of the widely consumed staple foods among the world's human population. Its production is adversely affected by high temperature and is more pronounced at flowering stage. Elucidating elevated temperature stress-related proteins as well as associated mechanisms is inevitable for improving heat tolerance in rice. In the present study, a proteomic analysis of heat-sensitive rice genotype, IET 21405 was conducted. Two-dimensional electrophoresis (2-DE) and MALDI-TOF/MS-based proteomics approaches revealed a total of 73 protein spots in rice leaf. The protein profiles clearly indicated variations in protein expression between the control and heat treated rice genotypes. Functional assessment of 73 expressed proteins revealed several mechanisms thought to be involved in high temperature including their putative role in metabolism, energy, protein synthesis, protein transport/storage, etc. Besides these, some proteins are expected to involve in photosynthesis, tricarboxylic acid (TCA) cycle, glycolysis and other proteins for energy production. The proteins identified in the present study provide a strong basis to elucidate gene function of these proteins and to explain further the molecular mechanisms underlying the adaptation of rice to high temperature stress.

  4. Migration of radionuclides following shallow land burial

    International Nuclear Information System (INIS)

    Sedlet, J.; Golchert, N.W.

    1980-01-01

    The site of a former nuclear laboratory and shallow land burial facility 25 km southwest of Chicago (USA) has been examined for radionuclide migration and residual radioactive materials. The radioactivity was produced during operations with the first nuclear reactors and associated research from 1943 to 1955. The chronology of events and details of the decommissioning procedures, including reactor burial, are described. Surface soil, surface water, soil borings drilled through and around the facility, and water from the dolomite aquifer and glacial till overburden were analyzed for a variety of radionuclides. The only nuclide found to have migrated out of the burial site is hydrogen-3, as tritiated water. This nuclide was detected in surface water, soil water, and nearby picnic wells. The concentrations in the wells show a seasonal fluctuation, from 0.1 nCi/t in the summer to 14 nCi/l in the recharging of the groundwater winter, that is attributed to by spring rains. Water migration rates in the glacial till and dolomite were estimated by several methods. The time of travel of water to the nearest well, 400 m from the facility, is estimated to be 58 months. The vertical and horizontal distribution of tritium in the glacial till was measured. The origin of the tritium, neutron-irradiated lithium, was established from measurements of the hydrogen isotopic ratios. Concentrations of other radionuclides in soil and water were normal, except for plutonium (at about twice fallout concentrations) in the first 2 m below the buried material. The solid-element nuclides have migrated very little. Exposure pathways and their associated doses, and procedures for retarding further migration are discUssed. (author)

  5. Great Moravian burial grounds in Rajhrad and Rajhradice

    OpenAIRE

    Hendrychová, Soňa

    2015-01-01

    The diploma thesis presented deals with an overall assessment of the Great Moravian burial ground in Rajhrad (Brno- venkov), which was excavated in the years 1972 to 1976. The work is based on a catalogue of this burial ground and the neighbouring one in Rajhradice published by Čeněk Staňa. It follows individual aspects of funeral rites at a necropolis and evaluates the inventory of the graves. Based on the findings, the work dates the burial ground, compares with burial ground in Rajhradice ...

  6. Cleanup Verification Package for the 118-F-1 Burial Ground

    Energy Technology Data Exchange (ETDEWEB)

    E. J. Farris and H. M. Sulloway

    2008-01-10

    This cleanup verification package documents completion of remedial action for the 118-F-1 Burial Ground on the Hanford Site. This burial ground is a combination of two locations formerly called Minor Construction Burial Ground No. 2 and Solid Waste Burial Ground No. 2. This waste site received radioactive equipment and other miscellaneous waste from 105-F Reactor operations, including dummy elements and irradiated process tubing; gun barrel tips, steel sleeves, and metal chips removed from the reactor; filter boxes containing reactor graphite chips; and miscellaneous construction solid waste.

  7. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    International Nuclear Information System (INIS)

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Brown, D.W.; Clausen, B.; An, Ke; Choo, Hahn; Hubbard, Camden R.; David, Stan A.

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in-situ, time-resolved neutron diffraction technique. A method is developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld

  8. Optimization of Residual Stress of High Temperature Treatment Using Genetic Algorithm and Neural Network

    Directory of Open Access Journals (Sweden)

    M. Susmikanti

    2015-12-01

    Full Text Available In a nuclear industry area, high temperature treatment of materials is a factor which requires special attention. Assessment needs to be conducted on the properties of the materials used, including the strength of the materials. The measurement of material properties under thermal processes may reflect residual stresses. The use of Genetic Algorithm (GA to determine the optimal residual stress is one way to determine the strength of a material. In residual stress modeling with several parameters, it is sometimes difficult to solve for the optimal value through analytical or numerical calculations. Here, GA is an efficient algorithm which can generate the optimal values, both minima and maxima. The purposes of this research are to obtain the optimization of variable in residual stress models using GA and to predict the center of residual stress distribution, using fuzzy neural network (FNN while the artificial neural network (ANN used for modeling. In this work a single-material 316/316L stainless steel bar is modeled. The minimal residual stresses of the material at high temperatures were obtained with GA and analytical calculations. At a temperature of 6500C, the GA optimal residual stress estimation converged at –711.3689 MPa at adistance of 0.002934 mm from center point, whereas the analytical calculation result at that temperature and position is -975.556 MPa . At a temperature of 8500C, the GA result was -969.868 MPa at 0.002757 mm from the center point, while with analytical result was -1061.13 MPa. The difference in residual stress between GA and analytical results at a temperatureof6500C is about 27 %, while at 8500C it is 8.67 %. The distribution of residual stress showed a grouping concentrated around a coordinate of (-76; 76 MPa. The residuals stress model is a degree-two polynomial with coefficients of 50.33, -76.54, and -55.2, respectively, with a standard deviation of 7.874.

  9. Shallow land burial - why or why not

    International Nuclear Information System (INIS)

    Thompson, W.T.; Ledbetter, J.O.; Rohlich, G.A.

    1979-01-01

    This paper summarizes a master's thesis on the state-of-the-art for shallow land burial of solid low-level radioactive wastes. The coverage of the thesis, which is condensed for this paper, ranges from site selection to problem case histories. Inherent in such coverage is the assessment of risk, the discussion of operational and management problems and the real significance of off-site migration. This topic is discussed in light of the stands taken that the migration is a serious problem and that it is not. Emphasis is on the engineering parameters of importance in site selection, and what pretreatment, if any, is needed

  10. Internal stress-induced melting below melting temperature at high-rate laser heating

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yong Seok, E-mail: yshwang@iastate.edu [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States); Levitas, Valery I., E-mail: vlevitas@iastate.edu [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-06-30

    In this Letter, continuum thermodynamic and phase field approaches (PFAs) predicted internal stress-induced reduction in melting temperature for laser-irradiated heating of a nanolayer. Internal stresses appear due to thermal strain under constrained conditions and completely relax during melting, producing an additional thermodynamic driving force for melting. Thermodynamic melting temperature for Al reduces from 933.67 K for a stress-free condition down to 898.1 K for uniaxial strain and to 920.8 K for plane strain. Our PFA simulations demonstrated barrierless surface-induced melt nucleation below these temperatures and propagation of two solid-melt interfaces toward each other at the temperatures very close to the corresponding predicted thermodynamic equilibrium temperatures for the heating rate Q≤1.51×10{sup 10}K/s. At higher heating rates, kinetic superheating competes with a reduction in melting temperature and melting under uniaxial strain occurs at 902.1 K for Q = 1.51 × 10{sup 11 }K/s and 936.9 K for Q = 1.46 × 10{sup 12 }K/s.

  11. Exogenous calcium alleviates low night temperature stress on the photosynthetic apparatus of tomato leaves.

    Directory of Open Access Journals (Sweden)

    Guoxian Zhang

    Full Text Available The effect of exogenous CaCl2 on photosystem I and II (PSI and PSII activities, cyclic electron flow (CEF, and proton motive force of tomato leaves under low night temperature (LNT was investigated. LNT stress decreased the net photosynthetic rate (Pn, effective quantum yield of PSII [Y(II], and photochemical quenching (qP, whereas CaCl2 pretreatment improved Pn, Y(II, and qP under LNT stress. LNT stress significantly increased the non-regulatory quantum yield of energy dissipation [Y(NO], whereas CaCl2 alleviated this increase. Exogenous Ca2+ enhanced stimulation of CEF by LNT stress. Inhibition of oxidized PQ pools caused by LNT stress was alleviated by CaCl2 pretreatment. LNT stress reduced zeaxanthin formation and ATPase activity, but CaCl2 pretreatment reversed both of these effects. LNT stress caused excess formation of a proton gradient across the thylakoid membrane, whereas CaCl2 pretreatment decreased the said factor under LNT. Thus, our results showed that photoinhibition of LNT-stressed plants could be alleviated by CaCl2 pretreatment. Our findings further revealed that this alleviation was mediated in part by improvements in carbon fixation capacity, PQ pools, linear and cyclic electron transports, xanthophyll cycles, and ATPase activity.

  12. Exogenous calcium alleviates low night temperature stress on the photosynthetic apparatus of tomato leaves.

    Science.gov (United States)

    Zhang, Guoxian; Liu, Yufeng; Ni, Yang; Meng, Zhaojuan; Lu, Tao; Li, Tianlai

    2014-01-01

    The effect of exogenous CaCl2 on photosystem I and II (PSI and PSII) activities, cyclic electron flow (CEF), and proton motive force of tomato leaves under low night temperature (LNT) was investigated. LNT stress decreased the net photosynthetic rate (Pn), effective quantum yield of PSII [Y(II)], and photochemical quenching (qP), whereas CaCl2 pretreatment improved Pn, Y(II), and qP under LNT stress. LNT stress significantly increased the non-regulatory quantum yield of energy dissipation [Y(NO)], whereas CaCl2 alleviated this increase. Exogenous Ca2+ enhanced stimulation of CEF by LNT stress. Inhibition of oxidized PQ pools caused by LNT stress was alleviated by CaCl2 pretreatment. LNT stress reduced zeaxanthin formation and ATPase activity, but CaCl2 pretreatment reversed both of these effects. LNT stress caused excess formation of a proton gradient across the thylakoid membrane, whereas CaCl2 pretreatment decreased the said factor under LNT. Thus, our results showed that photoinhibition of LNT-stressed plants could be alleviated by CaCl2 pretreatment. Our findings further revealed that this alleviation was mediated in part by improvements in carbon fixation capacity, PQ pools, linear and cyclic electron transports, xanthophyll cycles, and ATPase activity.

  13. Psychogenic fever: how psychological stress affects body temperature in the clinical population

    Science.gov (United States)

    Oka, Takakazu

    2015-01-01

    Psychogenic fever is a stress-related, psychosomatic disease especially seen in young women. Some patients develop extremely high core body temperature (Tc) (up to 41°C) when they are exposed to emotional events, whereas others show persistent low-grade high Tc (37–38°C) during situations of chronic stress. The mechanism for psychogenic fever is not yet fully understood. However, clinical case reports demonstrate that psychogenic fever is not attenuated by antipyretic drugs, but by psychotropic drugs that display anxiolytic and sedative properties, or by resolving patients' difficulties via natural means or psychotherapy. Animal studies have demonstrated that psychological stress increases Tc via mechanisms distinct from infectious fever (which requires proinflammatory mediators) and that the sympathetic nervous system, particularly β3-adrenoceptor-mediated non-shivering thermogenesis in brown adipose tissue, plays an important role in the development of psychological stress-induced hyperthermia. Acute psychological stress induces a transient, monophasic increase in Tc. In contrast, repeated stress induces anticipatory hyperthermia, reduces diurnal changes in Tc, or slightly increases Tc throughout the day. Chronically stressed animals also display an enhanced hyperthermic response to a novel stress, while past fearful experiences induce conditioned hyperthermia to the fear context. The high Tc that psychogenic fever patients develop may be a complex of these diverse kinds of hyperthermic responses. PMID:27227051

  14. Necropolis on Bor lake: New reports on Bronze age burial

    Directory of Open Access Journals (Sweden)

    Kapuran Aleksandar

    2011-01-01

    Full Text Available This article deals with the social and anthropological aspects of burial rituals during the Middle Bronze Age in Timočka Krajina. Decades of systematic research of necropolises and reconnaissance in the basin of the Crni Timok proved an increase in number of sites around ore - rich areas of the east Kučaj mountains as well as around Romuliana site and the fertile valleys of Džanovo polje (Map. 1. The quantitative increase in settlements was reflected by the emergence of large necropolises, only three of which have been systematically explored; those in Trnjani, Magura and Bor Lake (Fig. 1; Plan 1. Analysis of geographical features of many settlements and their position in relation to natural resources helped define two communities, one of which carried out mining and metallurgical activities, while the other group engaged in the production of food. Both groups lived in the immediate vicinity and mutual dependence, functioning within a developed market for copper production. During the exploration of the necropolis near Bor Lake in 1997, the remains of burnt skeletons were collected from burial structures 2/97 and 13/97 (Fig. 2; Plans 2 and 3. Anthropological analysis of the cremated remains of the deceased showed that high temperatures were used during the cremation process, which we assume could have only been achieved in metallurgical furnaces. This is confirmed by the fact that the skeletal fragments contain traces of melted metal, as well as finds of bronze slag inside urns and grave structures in the necropolis in Trnjani (Figs. 3 and 4; Tables 1-4. Burial ritual of this kind was not proved by systematic archaeological research of necropolises in the basin of Crni Timok, although anthropological data collected from necropolises linked to metallurgical settlements may indicate some guidelines in the ritual cremation of prominent members of these communities. [Projekat Ministarstva nauke Republike Srbije, br. 177020: Arheologija Srbije

  15. Stress analysis in high-temperature superconductors under pulsed field magnetization

    Science.gov (United States)

    Wu, Haowei; Yong, Huadong; Zhou, Youhe

    2018-04-01

    Bulk high-temperature superconductors (HTSs) have a high critical current density and can trap a large magnetic field. When bulk superconductors are magnetized by the pulsed field magnetization (PFM) technique, they are also subjected to a large electromagnetic stress, and the resulting thermal stress may cause cracking of the superconductor due to the brittle nature of the sample. In this paper, based on the H-formulation and the law of heat transfer, we can obtain the distributions of electromagnetic field and temperature, which are in qualitative agreement with experiment. After that, based on the dynamic equilibrium equations, the mechanical response of the bulk superconductor is determined. During the PFM process, the change in temperature has a dramatic effect on the radial and hoop stresses, and the maximum radial and hoop stress are 24.2 {{MPa}} and 22.6 {{MPa}}, respectively. The mechanical responses of a superconductor for different cases are also studied, such as the peak value of the applied field and the size of bulk superconductors. Finally, the stresses are also presented for different magnetization methods.

  16. Electrodeposition of nickel from low temperature sulfamate electrolytes.Part 1 :Electrochemistry and film stress.

    Energy Technology Data Exchange (ETDEWEB)

    Hachman, John T.; Kelly, J.J. (IBM/T.J. Watson Research Center, Yorktown Heights, NY); Talin, Albert Alec; Goods, Steven Howard

    2005-11-01

    The film stress of Ni films deposited at near-ambient temperatures from sulfamate electrolytes was studied. The particulate filtering of the electrolyte, a routine industrial practice, becomes an important deposition parameter at lower bath temperatures. At 28 C, elevated tensile film stress develops at low current densities (<10 mA/cm{sup 2}) if the electrolyte is filtered. Filtering at higher current densities has a negligible effect on film stress. A similar though less pronounced trend is observed at 32 C. Sulfate-based Ni plating baths display similar film stress sensitivity to filtering, suggesting that this is a general effect for Ni electrodeposition. It is shown that filtering does not significantly change the current efficiency or the pH near the surface during deposition. The observed changes in film stress are thus attributed not to adsorbed hydrogen but instead to the effects of filtering on the formation and concentration of polyborate species due to the decreased solubility of boric acid at near-ambient temperatures.

  17. ANALYSIS OF STRESS STATE IN UPPER LAYER OF ROAD CONCRETE PAVEMENT WITH TEMPERATURE ACTION

    Directory of Open Access Journals (Sweden)

    M. K. Pshembaev

    2017-01-01

    Full Text Available While being operated auto-road pavements are subjected to intensive mechanical impacts, ultraviolet ray irradiation, freeze-thaw temperatures, freezing and thawing, drying and moistening. Due to these actions various types of pavement distresses appear on the road pavement. The most significant and dangerous type of distresses is micro-cracks on the road surface. One of the main reasons for their formation is an action of weather and climatic factors that initiate large changes in temperature of coating surface and occurrence of large temperature gradients in the upper layer. In this context while designing and operating auto-roads it is rather essential to investigate a stress state in road surface which is caused by temperature action. Purpose of the described investigations is to determine permissible temperature gradients for cement-concrete pavements that exclude formation of micro-cracks on their surface and thickness of damaged surface layer. Calculations of road pavement have been carried out at various laws for temperature distribution in its depth. A finite difference method realized in PARUS software has been used for studying a stress state of cement-concrete auto-roads. Regularities for distribution of stresses in cement-concrete pavement of auto-roads have been obtained at various surface temperatures. Permissible temperature gradients in the upper pavement layer have been determined and thickness of the layer where micro-cracks are formed has been assessed in the paper. Strength criterion based on the process of micro-crack formation and development in the concrete has been used for calculations. Risk of micro-crack formation on the auto-road pavement depends on material strength, conditions of plate fixing and temperature gradients.

  18. Temperature and stress distribution in pressure vessel by the boundary element method

    International Nuclear Information System (INIS)

    Alujevic, A.; Apostolovic, D.

    1990-01-01

    The aim of this paper is to demonstrate the applicability of boundary element method for the solution of temperatures and thermal stresses in the body of reactor pressure vessel of the NPP Krsko . In addition to the theory of boundary elements for thermo-elastic continua (2D, 3D) results are given of a numerically evaluated meridional cross-section. (author)

  19. Transient temperature and stress distributions in the pressure vessel's wall of a nuclear reactor

    International Nuclear Information System (INIS)

    Silva, G.A. da

    1979-01-01

    In order to calculate the temperature distribution in a reactor vessel wall which is under the effect of gamma radiation originated in the reactor core, a numerical solution is proposed. This problem may arise from a reactor cooling pump failure .The thermal stresses are also calculated. (Author) [pt

  20. The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

  1. Viscosity, granular-temperature, and stress calculations for shearing assemblies of inelastic, frictional disks

    International Nuclear Information System (INIS)

    Walton, O.R.; Braun, R.L.

    1986-01-01

    Employing nonequilibrium molecular-dynamics methods the effects of two energy loss mechanisms on viscosity, stress, and granular-temperature in assemblies of nearly rigid, inelastic frictional disks undergoing steady-state shearing are calculated. Energy introduced into the system through forced shearing is dissipated by inelastic normal forces or through frictional sliding during collisions resulting in a natural steady-state kinetic energy density (granular-temperature) that depends on the density and shear rate of the assembly and on the friction and inelasticity properties of the disks. The calculations show that both the mean deviatoric particle velocity and the effective viscosity of a system of particles with fixed friction and restitution coefficients increase almost linearly with strain rate. Particles with a velocity-dependent coefficient of restitution show a less rapid increase in both deviatoric velocity and viscosity as strain rate increases. Particles with highly dissipative interactions result in anisotropic pressure and velocity distributions in the assembly, particularly at low densities. At very high densities the pressure also becomes anisotropic due to high contact forces perpendicular to the shearing direction. The mean rotational velocity of the frictional disks is nearly equal to one-half the shear rate. The calculated ratio of shear stress to normal stress varies significantly with density while the ratio of shear stress to total pressure shows much less variation. The inclusion of surface friction (and thus particle rotation) decreases shear stress at low density but increases shear stress under steady shearing at higher densities

  2. Plasticity in behavioural responses and resistance to temperature stress in Musca domestica

    DEFF Research Database (Denmark)

    Kjaersgaard, Anders; Blackenhorn, Wolf U.; Pertoldi, Cino

    2015-01-01

    , at the stressful high temperature Spanish flies flew the furthest and Danish flies the shortest distance. Neither body size nor wing loading affected flight performance, although flies with narrower wings tended to fly further (wing shape effect). Swiss flies were most active in terms of locomotor activity......Organisms can respond to and cope with stressful environments in a number of ways including behavioural, morphological and physiological adjustments. To understand the role of behavioural traits in thermal adaptations we compared heat resistance, locomotor (walking and flying) activity, flight...... performance and morphology of three European populations of Musca domestica (Diptera: Muscidae) originating from different thermal conditions (Spain, Switzerland and Denmark) at benign and stressful high temperatures. Spanish flies showed greater heat resistance than Swiss and Danish flies. Similarly...

  3. Evidence for adaptive evolution of low-temperature stress response genes in a Pooideae grass ancestor

    DEFF Research Database (Denmark)

    Vigeland, Magnus D; Spannagl, Manuel; Asp, Torben

    2013-01-01

    Adaptation to temperate environments is common in the grass subfamily Pooideae, suggesting an ancestral origin of cold climate adaptation. Here, we investigated substitution rates of genes involved in low-temperature-induced (LTI) stress responses to test the hypothesis that adaptive molecular ev...... evidence for a link between adaptation to cold habitats and adaptive evolution of LTI stress responses in early Pooideae evolution and shed light on a poorly understood chapter in the evolutionary history of some of the world's most important temperate crops......Adaptation to temperate environments is common in the grass subfamily Pooideae, suggesting an ancestral origin of cold climate adaptation. Here, we investigated substitution rates of genes involved in low-temperature-induced (LTI) stress responses to test the hypothesis that adaptive molecular...

  4. Temperature tolerance and stress proteins as mechanisms of invasive species success.

    Directory of Open Access Journals (Sweden)

    Robyn A Zerebecki

    2011-04-01

    Full Text Available Invasive species are predicted to be more successful than natives as temperatures increase with climate change. However, few studies have examined the physiological mechanisms that theoretically underlie this differential success. Because correlative evidence suggests that invasiveness is related to the width of a species' latitudinal range, it has been assumed--but largely untested--that range width predicts breadth of habitat temperatures and physiological thermotolerances. In this study, we use empirical data from a marine community as a case study to address the hypotheses that (1 geographic temperature range attributes are related to temperature tolerance, leading to greater eurythermality in invasive species, and (2 stress protein expression is a subcellular mechanism that could contribute to differences in thermotolerance. We examined three native and six invasive species common in the subtidal epibenthic communities of California, USA. We assessed thermotolerance by exposing individuals to temperatures between 14°C and 31°C and determining the temperature lethal to 50% of individuals (LT(50 after a 24 hour exposure. We found a strong positive relationship between the LT(50 and both maximum habitat temperatures and the breadth of temperatures experience across the species' ranges. In addition, of the species in our study, invasives tended to inhabit broader habitat temperature ranges and higher maximum temperatures. Stress protein expression may contribute to these differences: the more thermotolerant, invasive species Diplosoma listerianum expressed higher levels of a 70-kDa heat-shock protein than the less thermotolerant, native Distaplia occidentalis for which levels declined sharply above the LT(50. Our data highlight differences between native and invasive species with respect to organismal and cellular temperature tolerances. Future studies should address, across a broader phylogenetic and ecosystem scope, whether this

  5. High carotenoids content can enhance resistance of selected Pinctada fucata families to high temperature stress.

    Science.gov (United States)

    Meng, Zihao; Zhang, Bo; Liu, Baosuo; Li, Haimei; Fan, Sigang; Yu, Dahui

    2017-02-01

    Carotenoids are a class of natural antioxidants widely found in aquatic, and they have significant effects on the growth, survival, and immunity of these organisms. To investigate the mechanisms of carotenoids in high temperature resistance, we observed the immune response of selected pearl oyster Pinctada fucata (Akoya pearl oyster) families with different carotenoids contents to high temperature stress. The results indicated that the survival rate (SR) of P. fucata decreased significantly with increase in temperature from 26 °C to 34 °C and with the decrease of total carotenoids content (TCC); when the TCC was higher, the SR tended to be higher. TCC and total antioxidant capacity (TAC) decreased significantly at 30 °C with increasing stress time. Correlation analysis indicated that TAC was positively and linearly correlated with TCC, and SR was S-type correlated with TCC and TAC. Immune analysis indicated that levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in selected families (with higher TCC) under temperature stress (at 30 °C) were generally significantly lower than in the control group (with lowest TCC) and from 0 to 96 h, the levels of each of these substances varied significantly. Levels of SOD, CAT, and MDA within each family first rose from 0 to 3 h, then decreased to their lowest point after 24 h, and then rose again to their highest levels at 96 h. When TCC was higher, the levels of SOD, CAT, and MDA tended to be lower. These findings indicated that carotenoids play an important role in improving survival rates of P. fucata under high temperature stress by enhancing animals' antioxidant system, and could serve as an index for breeding stress-resistant lines in selective breeding practices. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Conflicting deductions from machining and other tests, concerning flow stress at high strain rates and temperatures

    International Nuclear Information System (INIS)

    Childs, T.H.C.

    1974-01-01

    This paper is concerned with the friction interaction between an En1A chip and a cemented tungsten--titanium carbide cutting tool during turning En1A on a lathe at speeds between 0.25 and 7.5 m s -1 and at feeds of 0.13 and 0.26 mm rev -1 . The mean friction stress has been measured and deductions made from chip shape measurements about the variation of the friction stress over the rake face. Three regimes of continuous chip formation were seen. In the first, the mean friction stress was independent of strain rate and temperature, in the second it depended on temperature and in the third, at the highest cutting speeds, it depended on temperature and feed. In the third regime, softening of the chip material caused by frictional heating limited the friction force, but the softening temperature depended on the heating rate of the chip material. Softening occurred at 700 0 C when the rate of heating from room temperature was 5.4 x 10 5 0 C s -1 and at 1160 0 C when the rate was 1.7 x 10 7 0 C s -1 . (U.S.)

  7. On The Stress Free Deformation Of Linear FGM Interface Under Constant Temperature

    Directory of Open Access Journals (Sweden)

    Ganczarski Artur

    2015-09-01

    Full Text Available This paper demonstrates the stress free thermo-elastic problem of the FGM thick plate. Existence of such a purely thermal deformation is proved in two ways. First proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations. This reduces 3D problem to the plane stress state problem. Next it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient. Second proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation. This occurs if only stress field is homogeneous in domain and at boundary. Finally an example of application to an engineering problem is presented.

  8. Irradiation-assisted stress corrosion cracking considerations at temperatures below 288 degree C

    International Nuclear Information System (INIS)

    Simonen, E.P.; Jones, R.H.; Bruemmer, S.M.

    1995-03-01

    Irradiation-assisted stress corrosion cracking (IASCC) occurs above a critical neutron fluence in light-water reactor (LWR) water environments at 288 C, but very little information exists to indicate susceptibility as temperatures are reduced. Potential low-temperature behavior is assessed based on the temperature dependencies of intergranular (IG) SCC in the absence of irradiation, radiation-induced segregation (RIS) at grain boundaries and micromechanical deformation mechanisms. IGSCC of sensitized SS in the absence of irradiation exhibits high growth rates at temperatures down to 200 C under conditions of anodic dissolution control, while analysis of hydrogen-induced cracking suggests a peak crack growth rate near 100 C. Hence from environmental considerations, IASCC susceptibility appears to remain likely as water temperatures are decreased. Irradiation experiments and model predictions indicate that RIS also persists to low temperatures. Chromium depletion may be significant at temperatures below 100C for irradiation doses greater than 10 displacements per atom (dpa). Macromechanical effects of irradiation on strength and ductility are not strongly dependent on temperature below 288 C. However, temperature does significantly affect radiation effects on SS microstructure and micromechanical deformation mechanisms. The critical conditions for material susceptibility to IASCC at low temperatures may be controlled by radiation-induced grain boundary microchemistry, strain localization due to irradiation microstructure and irradiation creep processes. 39 refs

  9. Two Temperature Magneto-Thermoelasticity with Initial Stress: State Space Formulation

    Directory of Open Access Journals (Sweden)

    Sunita Deswal

    2013-01-01

    Full Text Available Magneto-thermoelastic interactions in an initially stressed isotropic homogeneous elastic half-space with two temperatures are studied using mathematical methods under the purview of the L-S model of linear theory of generalized thermoelasticity. The formalism deals with the state space approach with the purpose of counteracting the difficulties of handling the displacement potential functions. Of specific concern here is the propagation of waves owing to ramp type increase in temperature and load. The medium is considered to be permeated by a uniform magnetic field. The expressions for different field parameters such as displacement, temperature, strain, and stress in the physical domain are obtained by applying a numerical inversion technique. Results of some earlier workers have been deduced from the present formulation. Numerical work is also performed for a suitable material with the aim of illustrating the results.

  10. Body temperature responses to handling stress in wintering Black-capped Chickadees (Poecile atricapillus L.).

    Science.gov (United States)

    Lewden, Agnès; Nord, Andreas; Petit, Magali; Vézina, François

    2017-10-01

    Body temperature variation in response to acute stress is typically characterized by peripheral vasoconstriction and a concomitant increase in core body temperature (stress-induced hyperthermia). It is poorly understood how this response differs between species and within individuals of the same species, and how it is affected by the environment. We therefore investigated stress-induced body temperature changes in a non-model species, the Black-capped Chickadee, in two environmental conditions: outdoors in low ambient temperature (mean: -6.6°C), and indoors, in milder ambient temperature close to thermoneutrality (mean: 18.7°C). Our results show that the change in body temperature in response to the same handling stressor differs in these conditions. In cold environments, we noted a significant decrease in core body temperature (-2.9°C), whereas the response in mild indoor conditions was weak and non-significant (-0.6°C). Heat loss in outdoor birds was exacerbated when birds were handled for longer time. This may highlight the role of behavioral thermoregulation and heat substitution from activity to body temperature maintenance in harsh condition. Importantly, our work also indicates that changes in the physical properties of the bird during handling (conductive cooling from cold hands, decreased insulation from compression of plumage and prevention of ptiloerection) may have large consequences for thermoregulation. This might explain why females, the smaller sex, lost more heat than males in the experiment. Because physiological and physical changes during handling may carry over to affect predation risk and maintenance of energy balance during short winter days, we advice caution when designing experimental protocols entailing prolonged handling of small birds in cold conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Low Temperature In-Situ Stress Measurement of W/Cu Composite by Neutron Diffraction

    Science.gov (United States)

    Nishida, Masayuki; Muslih, M. Rifai; Ikeuchi, Yasukazu; Minakawa, Nobuaki; Hanabusa, Takao

    The internal stresses in the continuous tungsten-fiber reinforced copper-matrix composite were examined by the Neutron stress measurement method. The Neutron diffraction apparatus ND1, which is abbreviated from the Neutron Diffraction system No.1 designed and manufactured by the National Nuclear Energy Agency in Indonesia (Badan Tenage Nuklir Nasional, BATAN), was used in the present study. The most common 3-axes measurement method with Hooke's equation was used to measure stresses in the both of tungsten-fiber and copper-matrix. The tungsten-fiber became the situation of heavy 110 priority orientation. The other hand, copper-matrix became the large crystal grain. Thermal stress alterations caused form low temperature cycling was measured by in-situ stress measurement method making use of a cryostat system. The thermal residual stresses of tungsten-fiber and copper-matrix in longitudinal direction were compressive and tensile state respectively. Results of in-situ thermal stress measurement were agreed with a calculated result of simple elastic theory qualitatively.

  12. Orexinergic neurotransmission in temperature responses to methamphetamine and stress: mathematical modeling as a data assimilation approach.

    Directory of Open Access Journals (Sweden)

    Abolhassan Behrouzvaziri

    Full Text Available Orexinergic neurotransmission is involved in mediating temperature responses to methamphetamine (Meth. In experiments in rats, SB-334867 (SB, an antagonist of orexin receptors (OX1R, at a dose of 10 mg/kg decreases late temperature responses (t > 60 min to an intermediate dose of Meth (5 mg/kg. A higher dose of SB (30 mg/kg attenuates temperature responses to low dose (1 mg/kg of Meth and to stress. In contrast, it significantly exaggerates early responses (t < 60 min to intermediate and high doses (5 and 10 mg/kg of Meth. As pretreatment with SB also inhibits temperature response to the stress of injection, traditional statistical analysis of temperature responses is difficult.We have developed a mathematical model that explains the complexity of temperature responses to Meth as the interplay between excitatory and inhibitory nodes. We have extended the developed model to include the stress of manipulations and the effects of SB. Stress is synergistic with Meth on the action on excitatory node. Orexin receptors mediate an activation of on both excitatory and inhibitory nodes by low doses of Meth, but not on the node activated by high doses (HD. Exaggeration of early responses to high doses of Meth involves disinhibition: low dose of SB decreases tonic inhibition of HD and lowers the activation threshold, while the higher dose suppresses the inhibitory component. Using a modeling approach to data assimilation appears efficient in separating individual components of complex response with statistical analysis unachievable by traditional data processing methods.

  13. Reference genes selection and normalization of oxidative stress responsive genes upon different temperature stress conditions in Hypericum perforatum L.

    Directory of Open Access Journals (Sweden)

    Isabel Velada

    Full Text Available Reverse transcription-quantitative real-time PCR (RT-qPCR is a widely used technique for gene expression analysis. The reliability of this method depends largely on the suitable selection of stable reference genes for accurate data normalization. Hypericum perforatum L. (St. John's wort is a field growing plant that is frequently exposed to a variety of adverse environmental stresses that can negatively affect its productivity. This widely known medicinal plant with broad pharmacological properties (anti-depressant, anti-tumor, anti-inflammatory, antiviral, antioxidant, anti-cancer, and antibacterial has been overlooked with respect to the identification of reference genes suitable for RT-qPCR data normalization. In this study, 11 candidate reference genes were analyzed in H. perforatum plants subjected to cold and heat stresses. The expression stability of these genes was assessed using GeNorm, NormFinder and BestKeeper algorithms. The results revealed that the ranking of stability among the three algorithms showed only minor differences within each treatment. The best-ranked reference genes differed between cold- and heat-treated samples; nevertheless, TUB was the most stable gene in both experimental conditions. GSA and GAPDH were found to be reliable reference genes in cold-treated samples, while GAPDH showed low expression stability in heat-treated samples. 26SrRNA and H2A had the highest stabilities in the heat assay, whereas H2A was less stable in the cold assay. Finally, AOX1, AOX2, CAT1 and CHS genes, associated with plant stress responses and oxidative stress, were used as target genes to validate the reliability of identified reference genes. These target genes showed differential expression profiles over time in treated samples. This study not only is the first systematic analysis for the selection of suitable reference genes for RT-qPCR studies in H. perforatum subjected to temperature stress conditions, but may also provide

  14. Dialectics of Burial and Teritoriality in Barclays Ayakoroma's A ...

    African Journals Online (AJOL)

    This paper is conceived to investigate the subjects of death, burial, pride and territorial supremacy in African drama with special focus on A Matter of Honour by Barclays Ayakoroma. The study becomes crucial because the question of burial and struggle over rights of possession of a corpse by two parties has become a ...

  15. Urban Stream Burial Increases Watershed-Scale Nitrate Export.

    Directory of Open Access Journals (Sweden)

    Jake J Beaulieu

    Full Text Available Nitrogen (N uptake in streams is an important ecosystem service that reduces nutrient loading to downstream ecosystems. Here we synthesize studies that investigated the effects of urban stream burial on N-uptake in two metropolitan areas and use simulation modeling to scale our measurements to the broader watershed scale. We report that nitrate travels on average 18 times farther downstream in buried than in open streams before being removed from the water column, indicating that burial substantially reduces N uptake in streams. Simulation modeling suggests that as burial expands throughout a river network, N uptake rates increase in the remaining open reaches which somewhat offsets reduced N uptake in buried reaches. This is particularly true at low levels of stream burial. At higher levels of stream burial, however, open reaches become rare and cumulative N uptake across all open reaches in the watershed rapidly declines. As a result, watershed-scale N export increases slowly at low levels of stream burial, after which increases in export become more pronounced. Stream burial in the lower, more urbanized portions of the watershed had a greater effect on N export than an equivalent amount of stream burial in the upper watershed. We suggest that stream daylighting (i.e., uncovering buried streams can increase watershed-scale N retention.

  16. Customary right to befitting burial: a jurisprudential appraisal of four ...

    African Journals Online (AJOL)

    These symbols reveal unique rights for the people's entitlement. Among the rights to which an African is entitled is the right to befitting burial/funerals. This right comes with it, certain duties and/or obligations. The aim of this paper is to deconstruct the elements of applicable burial customs with a view to demonstrating their ...

  17. URBAN STREAM BURIAL INCREASES WATERSHED-SCALE NITRATE EXPORT

    Science.gov (United States)

    Nitrogen (N) uptake in streams is an important ecosystem service that may be affected by the widespread burial of streams in stormwater pipes in urban watersheds. We predicted that stream burial reduces the capacity of streams to remove nitrate (NO3-) from the water column by in...

  18. Fire hazards analysis for solid waste burial grounds

    International Nuclear Information System (INIS)

    McDonald, K.M.

    1995-01-01

    This document comprises the fire hazards analysis for the solid waste burial grounds, including TRU trenches, low-level burial grounds, radioactive mixed waste trenches, etc. It analyzes fire potential, and fire damage potential for these facilities. Fire scenarios may be utilized in future safety analysis work, or for increasing the understanding of where hazards may exist in the present operation

  19. 28-Homobrassinolide Modulate Antenna Complexes and Carbon Skeleton of Brassica juncea L. under Temperature Stress

    Directory of Open Access Journals (Sweden)

    Harpreet Kaur

    2014-08-01

    Full Text Available The aim of present study was to explore the ameliorative impact of 28-homoBL on morpho-physiological attributes, photosynthetic pigments and sugars of Brassica juncea L. exposed to oxidative stress caused by extreme temperatures (4 and 44 °C. For this, experiments were carried out at the Plant Physiology Laboratory, Department of Botany, Punjabi University, Patiala. Effect of different degrees of temperature (4 and 44 °C taking 24 °C as control was studied. 28-homoBL (10-6, 10-9 and 10-12M primed and unprimed seeds of B. juncea L. in terms of antenna complexes and end products of photosynthesis that is total carbohydrates and total soluble sugars was investigated. All concentrations of 28-homoBL used in present study showed different effects on morphology and light quenching pigments. All concentrations of 28-homoBL showed promoting effect on growth and light quenching pigments. The carbon makeup ameliorated positively in stressed and non-stressed components of photosynthetic machinery and 10-9 M 28-homoBL showed best results. In conclusion 28-homoBL showed great potential in protecting the reaction centre of photosynthetic machinery from oxidative stress caused by extreme low and high temperatures but in very dose dependent manner and thus modulate the carbon skeleton of the plant.

  20. Growth and photosynthesis of Chlorella strains from polar, temperate and tropical freshwater environments under temperature stress

    Science.gov (United States)

    Lee, Kok-Keong; Lim, Phaik-Eem; Poong, Sze-Wan; Wong, Chiew-Yen; Phang, Siew-Moi; Beardall, John

    2017-09-01

    Elevated temperatures as a consequence of global warming have significant impacts on the adaptation and survival of microalgae which are important primary producers in many ecosystems. The impact of temperature on the photosynthesis of microalgae is of great interest as the primary production of algal biomass is strongly dependent on the photosynthetic rates in a dynamic environment. Here, we examine the effects of elevated temperature on Chlorella strains originating from different latitudes, namely Antarctic, Arctic, temperate and tropical regions. Chlorophyll fluorescence was used to assess the photosynthetic responses of the microalgae. Rapid light curves (RLCs) and maximum quantum yield (F v/F m) were recorded. The results showed that Chlorella originating from different latitudes portrayed different growth trends and photosynthetic performance. The Chlorella genus is eurythermal, with a broad temperature tolerance range, but with strain-specific characteristics. However, there was a large overlap between the tolerance range of the four strains due to their "eurythermal adaptivity". Changes in the photosynthetic parameters indicated temperature stress. The ability of the four strains to reactivate photosynthesis after inhibition of photosynthesis under high temperatures was also studied. The Chlorella strains were shown to recover in terms of photosynthesis and growth (measured as Chl a) when they were returned to their ambient temperatures. Polar strains showed faster recovery in their optimal temperature compared to that under the ambient temperature from which they were isolated.

  1. Proteomic analysis of broccoli (Brassica oleracea) under high temperature and waterlogging stresses.

    Science.gov (United States)

    Lin, Hsin-Hung; Lin, Kuan-Hung; Chen, Su-Ching; Shen, Yu-Hsing; Lo, Hsiao-Feng

    2015-12-01

    The production of broccoli (Brassica oleracea) is largely reduced by waterlogging and high temperature stresses. Heat-tolerant and heat-susceptible broccoli cultivars TSS-AVRDC-2 and B-75, respectively, were used for physiological and proteomic analyses. The objective of this study was to identify TSS-AVRDC-2 and B-75 proteins differentially regulated at different time periods in response to waterlogging at 40 °C for three days. TSS-AVRDC-2 exhibited significantly higher chlorophyll content, lower stomatal conductance, and better H 2 O 2 scavenging under stress in comparison to B-75. Two-dimensional liquid phase fractionation analyses revealed that Rubisco proteins in both varieties were regulated under stressing treatments, and that TSS-AVRDC-2 had higher levels of both Rubisco large and small subunit transcripts than B-75 when subjected to high temperature and/or waterlogging. This report utilizes physiological and proteomic approaches to discover changes in the protein expression profiles of broccoli in response to heat and waterlogging stresses. Higher levels of Rubisco proteins in TSS-AVRDC-2 could lead to increased carbon fixation efficiency to provide sufficient energy to enable stress tolerance under waterlogging at 40 °C.

  2. Impact of abiotic stress on photosynthetic efficiency and leaf temperature in sunflower

    Directory of Open Access Journals (Sweden)

    Antonela Markulj Kulundžić

    2016-11-01

    Full Text Available The aim of this research was to investigate the variability of photosynthetic performance index (PIABS and leaf temperature values measured in V6 development phase on 13 sunflower hybrids, grown in stressful conditions. The pot trial was made up of two treatments, one (T1 with 60% Field Water Capacity (FWC, and the other one (T2 with 80% FWC. Significant differences between T1 and T2 treatments were established for both of these parameters which prove their dependence on the water content in the soil, while the influence of hybrid was evident only in the case of PIABS. Although in T1, as opposed to T2, all sunflower hybrids reacted by increasing leaf temperature, reaction to stress conditions measured with PIABS parameter was not uniform. Some of the hybrids reacted by decreasing PIABS values, while others reacted by increasing their PIABS values. Therefore, it can be concluded that changes in parameters were independent of each other, which was confirmed by correlation analysis. Investigated parameters are suitable for determining the existence of undesirable environmental conditions that cause stress in plants and can be used in breeding of sunflower to withstand abiotic stress conditions, i.e. in selection of stress tolerant hybrids.

  3. Antioxidant responses of Propylaea japonica (Coleoptera: Coccinellidae) exposed to high temperature stress.

    Science.gov (United States)

    Zhang, Shize; Fu, Wenyan; Li, Ning; Zhang, Fan; Liu, Tong-Xian

    2015-02-01

    Temperature is one of the most important environmental factors, and is responsible for a variety of physiological stress responses in organisms. Induced thermal stress is associated with elevated reactive oxygen species (ROS) generation leading to oxidative damage. The ladybeetle, Propylaea japonica (Thunberg) (Coleoptera: Coccinellidae), is considered a successful natural enemy because of its tolerance to high temperatures in arid and semi-arid areas in China. In this study, we investigated the effect of high temperatures (35, 37, 39, 41 and 43 °C) on the survival and activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidases (POD), glutathione-S-transferases (GST), and total antioxidant capacity (TAC) as well as malondialdehyde (MDA) concentrations in P. japonica adults. The results indicated that P. japonica adults could not survive at 43 °C. CAT, GST and TAC were significantly increased when compared to the control (25 °C), and this played an important role in the process of antioxidant response to thermal stress. SOD and POD activity, as well as MDA, did not differ significantly at 35 and 37 °C compared to the control; however, there were increased levels of SOD, POD and MDA when the temperature was above 37 °C. These results suggest that thermal stress leads to oxidative stress and antioxidant enzymes play important roles in reducing oxidative damage in P. japonica adults. This study represents the first comprehensive report on the antioxidant defense system in predaceous coccinellids (the third trophic level). The findings provide useful information for predicting population dynamics and understanding the potential for P. japonica as a natural enemy to control pest insects under varied environmental conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Polypyrrole/silver coaxial nanowire aero-sponges for temperature-independent stress sensing and stress-triggered Joule heating.

    Science.gov (United States)

    He, Weina; Li, Guangyong; Zhang, Shangquan; Wei, Yong; Wang, Jin; Li, Qingwen; Zhang, Xuetong

    2015-04-28

    To obtain ideal sensing materials with nearly zero temperature coefficient resistance (TCR) for self-temperature-compensated pressure sensors, we proposed an Incipient Network Conformal Growth (INCG) technology to prepare hybrid and elastic porous materials: the nanoparticles (NPs) are first dispersed in solvent to form an incipient network, another component is then introduced to coat the incipient network conformally via wet chemical route. The conformal coatings not only endow NPs with high stability but also offer them additional structural elasticity, meeting requirements for future generations of portable, compressive and flexible devices. The resultant polypyrrole/silver coaxial nanowire hybrid aero-sponges prepared via INCG technology have been processed into a piezoresistive sensor with highly sensing stability (low TCR 0.86 × 10(-3)/°C), sensitivity (0.33 kPa(-1)), short response time (1 ms), minimum detectable pressure (4.93 Pa) after suffering repeated stimuli, temperature change and electric heating. Moreover, a stress-triggered Joule heater can be also fabricated mainly by the PPy-Ag NW hybrid aero-sponges with nearly zero temperature coefficient.

  5. 118-B-1 burial ground excavation treatability test report

    International Nuclear Information System (INIS)

    1995-08-01

    This treatability investigation focused on the feasibility of excavating, analytical screening, and handling waste materials from the 118-B-1 Burial Ground located in the 100 B/C Area of the Hanford Site. The 118-B-1 Burial Ground consists of approximately 24 trenches on a 7-acre parcel. Solid low-level radioactive wastes and other debris and trash associated with reactor operations were disposed in 28 burial grounds in the 100 Area between 1944 and 1973. The majority of waste generated from routine reactor operations was placed in seven primary burial grounds, including 118-B-1. The 118-B-1 Burial Ground was selected as the location to perform this treatability test based on the availability of historical data for this site, and because it was thought to be representative of other primary-use burial grounds in the 100 Area. Geophysical surveys were conducted over the burial ground to map the concentrations of waste and aid in the selection of test pit excavation locations. The test plan developed for this study integrated the Streamlined Approach for Environmental Restoration (SAFER), a US Department of Energy (DOE) initiative based on both the Data Quality Objective (DQO) process and the observational approach. This treatability test is the first one at the Hanford Site to use the SAFER approach. The purpose of this study was (1) to support development of the Proposed Plan and Record of Decision, which would identify the approach to be used for burial ground remediation and (2) to provide specific engineering information for receiving waste generated from the 100 Area removal actions. The results of the treatability test can be used to determine the feasibility of performing excavation, analytical screening, and handling of burial ground materials from similar burial grounds

  6. Analysis of temperature and pressure distribution of containers for nuclear waste material disposal in space

    Science.gov (United States)

    Vanbibber, L. E.; Parker, W. G.

    1973-01-01

    A computer program was adapted from a previous generation program to analyze the temperature and internal pressure response of a radioactive nuclear waste material disposal container following impact on the earth. This program considers component melting, LiH dissociation, temperature dependent properties and pressure and container stress response. Analyses were performed for 21 cases with variations in radioactive power level, container geometry, degree of deformation of the container, degree of burial and soil properties. Results indicated that the integrity of SS-316 containers could be maintained with partial burials of either underformed or deformed containers. Results indicated that completely buried waste containers, with power levels above 5 kW, experienced creep stress rupture failures in 4 to 12 days.

  7. Effect of substrate preheating temperature and coating thickness on residual stress in plasma sprayed hydroxyapatite coating

    International Nuclear Information System (INIS)

    Tang, Dapei

    2015-01-01

    A thermal-mechanical coupling model was developed based on thermal-elastic- plastic theory according the special process of plasma spraying Hydroxyapatite (HA) coating upon Ti-6Al-4V substrate. On the one hand, the classical Fourier transient heat conduction equation was modified by introducing the effect item of deformation on temperature, on the other hand, the Johnson-Cook model, suitable for high temperature and high strain rate conditions, was used as constitutive equation after considering temperature softening effect, strain hardening effect and strain rate reinforcement effect. Based on the above coupling model, the residual stress field within the HA coating was simulated by using finite element method (FEM). Meanwhile, the substrate preheating temperature and coating thickness on the influence of residual stress components were calculated, respectively. The failure modes of coating were also preliminary analyzed. In addition, in order to verify the reliability of calculation, the material removal measurement technique was applied to determine the residual stress of HA coating near the interface. Some important conclusions are obtained. (paper)

  8. Microstructure and temperature dependence of intergranular strains on diffractometric macroscopic residual stress analysis

    International Nuclear Information System (INIS)

    Wagner, J.N.; Hofmann, M.; Wimpory, R.; Krempaszky, C.; Stockinger, M.

    2014-01-01

    Knowledge of the macroscopic residual stresses in components of complex high performance alloys is crucial when it comes to considering the safety and manufacturing aspects of components. Diffraction experiments are one of the key methods for studying residual stresses. However a component of the residual strain determined by diffraction experiments, known as microstrain or intergranular residual strain, occurs over the length scale of the grains and thus plays only a minor role for the life time of such components. For the reliable determination of macroscopic strains (with the minimum influence of these intergranular residual strains), the ISO standard recommends the use of particular Bragg reflections. Here we compare the build-up of intergranular strain of two different precipitation hardened IN 718 (INCONEL 718) samples, with identical chemical composition. Since intergranular strains are also affected by temperature, results from room temperature measurement are compared to results at T=550 °C. It turned out that microstructural parameters, such as grain size or type of precipitates, have a larger effect on the intergranular strain evolution than the influence of temperature at the measurement temperature of T=550 °C. The results also show that the choice of Bragg reflections for the diffractometric residual stress analysis is dependent not only on its chemical composition, but also on the microstructure of the sample. In addition diffraction elastic constants (DECs) for all measured Bragg reflections are given

  9. Breeding approaches and genomics technologies to increase crop yield under low-temperature stress.

    Science.gov (United States)

    Jha, Uday Chand; Bohra, Abhishek; Jha, Rintu

    2017-01-01

    Improved knowledge about plant cold stress tolerance offered by modern omics technologies will greatly inform future crop improvement strategies that aim to breed cultivars yielding substantially high under low-temperature conditions. Alarmingly rising temperature extremities present a substantial impediment to the projected target of 70% more food production by 2050. Low-temperature (LT) stress severely constrains crop production worldwide, thereby demanding an urgent yet sustainable solution. Considerable research progress has been achieved on this front. Here, we review the crucial cellular and metabolic alterations in plants that follow LT stress along with the signal transduction and the regulatory network describing the plant cold tolerance. The significance of plant genetic resources to expand the genetic base of breeding programmes with regard to cold tolerance is highlighted. Also, the genetic architecture of cold tolerance trait as elucidated by conventional QTL mapping and genome-wide association mapping is described. Further, global expression profiling techniques including RNA-Seq along with diverse omics platforms are briefly discussed to better understand the underlying mechanism and prioritize the candidate gene (s) for downstream applications. These latest additions to breeders' toolbox hold immense potential to support plant breeding schemes that seek development of LT-tolerant cultivars. High-yielding cultivars endowed with greater cold tolerance are urgently required to sustain the crop yield under conditions severely challenged by low-temperature.

  10. Subcellular proteomic characterization of the high-temperature stress response of the cyanobacterium Spirulina platensis

    Directory of Open Access Journals (Sweden)

    Cheevadhanarak Supapon

    2009-09-01

    Full Text Available Abstract The present study examined the changes in protein expression in Spirulina platensis upon exposure to high temperature, with the changes in expression analyzed at the subcellular level. In addition, the transcriptional expression level of some differentially expressed proteins, the expression pattern clustering, and the protein-protein interaction network were analyzed. The results obtained from differential expression analysis revealed up-regulation of proteins involved in two-component response systems, DNA damage and repair systems, molecular chaperones, known stress-related proteins, and proteins involved in other biological processes, such as capsule formation and unsaturated fatty acid biosynthesis. The clustering of all differentially expressed proteins in the three cellular compartments showed: (i the majority of the proteins in all fractions were sustained tolerance proteins, suggesting the roles of these proteins in the tolerance to high temperature stress, (ii the level of resistance proteins in the photosynthetic membrane was 2-fold higher than the level in two other fractions, correlating with the rapid inactivation of the photosynthetic system in response to high temperature. Subcellular communication among the three cellular compartments via protein-protein interactions was clearly shown by the PPI network analysis. Furthermore, this analysis also showed a connection between temperature stress and nitrogen and ammonia assimilation.

  11. Analysis of the temperature and stress distributions in ceramic window materials subjected to microwave heating

    International Nuclear Information System (INIS)

    Ferber, M.K.; Kimrey, H.D.; Becher, P.F.

    1983-07-01

    The temperature and stress and distributions generated in ceramic materials currently employed in microwave gyrotron tube windows were determined for a variety of operating conditions. Both edge- and face-cooled windows of either polycrystalline BeO or polycrystalline Al 2 O 3 were considered. The actual analysis involved three steps. First, a computer program was used to determine the electric field distribution within the window at a given power level and frequency (TE 02 wave propagation assumed). This program was capable of describing both the radial and axial dependence of the electric field. The effects of multiple internal reflections at the various dielectric interfaces were also accounted for. Secondly, the field distribution was used to derive an expression for the heat generated per unit volume per unit time within the window due to dieletric losses. A generalized heat conduction computer code was then used to compute the temperature distribution based on the heat generation function. Third, the stresses were determined from the temperature profiles using analytical expression or a finite-element computer program. Steady-state temperature and stress profiles were computed for the face-cooled and edge-cooled windows

  12. Impact of Brake Pad Structure on Temperature and Stress Fields of Brake Disc

    Directory of Open Access Journals (Sweden)

    Guoshun Wang

    2013-01-01

    Full Text Available Utilizing ABAQUS finite element software, the study established the relationship between a brake pad structure and distributions of temperature and thermal stress on brake disc. By introducing radial structure factor and circular structure factor concepts, the research characterized the effect of friction block radial and circumferential arrangement on temperature field of the brake disc. A method was proposed for improving heat flow distribution of the brake disc through optimizing the position of the friction block of the brake pad. Structure optimization was conducted on brake pads composed of 5 or 7 circular friction blocks. The result shows that, with the same overall contact area of friction pair, an appropriate brake pad structure can make the friction energy distribute evenly and therefore lowers peak temperature and stress of the brake disc. Compared with a brake pad of 7 friction blocks, an optimized brake pad of 5 friction blocks lowered the peak temperature of the corresponding brake disc by 4.9% and reduced the highest stress by 10.7%.

  13. Stress analysis in pipelines submitted to internal pressure - and temperature transients

    International Nuclear Information System (INIS)

    Mansur, T.R.

    1981-08-01

    Experimental determination of the structural behaviour of a thermal-hydraulic loop, when submitted to simultaneous fast change of pressure and temperature, was performed. For this, electrical strain-gages were positioned at some critical points in order to measure the deformation conditions of the structure. The study of the kinetics of the deformation revealed the presence of important transient stresses, mainly from thermal origin. After this transient behaviour, the structure is submitted to a thermal stress, which is shown to be strongly dependent on the degree of restraint of the structure. (Author) [pt

  14. Evolution of nanoscale interstitial dislocation loops under coupling effect of stress and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ning; Shen, Tielong; Kurtz, Richard; Wang, Zhiguang; Gao, Fei

    2017-07-01

    The properties of nano-scale interstitial dislocation loops under the coupling effect of stress and temperature are studied using atomistic simulation methods and experiments. The decomposition of a loop by the emission of smaller loops is identified as one of the major mechanisms to release the localized stress induced by the coupling effect, which is validated by the TEM observations. The classical conservation law of Burgers vector cannot be applied during such decomposition process. The dislocation network is formed from the decomposed loops, which may initiate the irradiation creep much earlier than expected through the mechanism of climb-controlled glide of dislocations.

  15. Transition from Slow to Fast Slip with Temperature, Forcing Velocity and Normal Stress: Experimental Evidence

    Science.gov (United States)

    Mitchell, E. K.; Brown, K. M.; Fialko, Y.

    2009-12-01

    We investigate frictional properties of K-feldspar bearing granite using a heated direct shear apparatus. We study the effects of temperature, applied forcing velocity and normal stress on the evolution of friction. We find that dramatic changes in slip rate and stress drop occur in response to changing experimental conditions. We perform two types of tests in this study: high sampling rate tests and hold tests. High sampling rate (10,000 Hz) tests reveal the effects of varying temperature, normal stress and forcing velocity on the amplitude, duration and velocity of individual slip events. Increasing temperature increases both slip amplitude and slip rate and decreases slip duration. Slip rates gradually increase as temperatures rise from 15 to 300 °C. However, we observe a dramatic jump in slip characteristics as temperatures rise from 300 to 400 °C; slip rates increase by two orders of magnitude from 0.17 to 10.46 mm/s. We speculate that the jump in slip velocities is related to the onset of substantial weakening of the quartz mineral phase and associated increases in contact area. The effect of increasing normal stress or decreasing forcing velocity is similar to but slightly different than temperature effects. We also tend to see increases in slip amplitude and velocity but slip time also increases. We also performed a series of hold tests to study the effect of temperature on the time dependent post slip healing of the frictional surface. We measure peak friction coefficient as a function of hold time at constant normal/shear load at 15, 300 and 500 °C. In rough agreement with results of Dieterich (1972), at 15°C the static coefficient of friction increases as a logarithm of hold time with a pre-multiplying coefficient. Raising temperature increases the value and rate of change of the static friction coefficient as a function of hold time. This suggests that post slip fault strengthening and the subsequent seismic stress drop are enhanced at higher

  16. Shrinkage stress kinetics of Bulk Fill resin-based composites at tooth temperature and long time.

    Science.gov (United States)

    Kalliecharan, David; Germscheid, William; Price, Richard B; Stansbury, Jeffrey; Labrie, Daniel

    2016-11-01

    To determine the shrinkage stress kinetics at up to 12h after light exposure and at tooth temperature during placement of selected Bulk Fill resin-based composites (RBCs). Five representative Bulk Fill RBCs from four companies were chosen with a wide range of viscosity and filler volume content. The shrinkage stress kinetics at T=33°C was measured continuously over a period of 12h using a modified tensometer with the ability to measure the cantilever beam deflection to better than 40nm accuracy at a sampling rate of up to 200 samples/s, and thermally stable resulting in a measurement accuracy better than 0.05MPa at 12h. The tensometer compliance was 0.105μm/N. A custom made heater was used to control the RBC sample temperature at T=33°C with a temperature gradient across the sample of less than 1°C. The samples were irradiated for 20s with irradiance of 1.1W/cm 2 and total energy density of 22J/cm 2 . Three samples (n=3) were used for each RBCs. The shrinkage stress at 12h for the five Bulk Fill RBCs ranged from 2.21 to 3.05MPa, maximum stress rate ((dS/dt) M ) varied from 0.18 to 0.41MPa/s, time at which the maximum stress rate occurred (t Max ) were between 1.42 to 3.24s and effective gel time (t gel ) varied from 50 to 770ms. Correlations were observed between (dS/dt) M and t Max (r=-0.946), t Max and filler volume fraction (r=-0.999), and between the shrinkage stress at 12h and t gel (r=0.994). However, no correlation was observed between the stress at 12h and filler volume fraction. The shrinkage stress for four of the five Bulk Fill RBCs were not significantly different (p<0.05) at 6h and beyond after photo-curing and that fully developed stress induced by photo-cured RBCs may only be reached at times longer than 12h. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Managing soil moisture on waste burial sites

    International Nuclear Information System (INIS)

    Anderson, J.E.; Ratzlaff, T.D.

    1991-11-01

    Shallow land burial is a common method of disposing of industrial, municipal, and low-level radioactive waste. The exclusion of water from buried wastes is a primary objective in designing and managing waste disposal sites. If wastes are not adequately isolated, water from precipitation may move through the landfill cover and into the wastes. The presence of water in the waste zone may promote the growth of plant roots to that depth and result in the transport of toxic materials to above-ground foliage. Furthermore, percolation of water through the waste zone may transport contaminants into ground water. This report presents results from a field study designed to assess the the potential for using vegetation to deplete soil moisture and prevent water from reaching buried wastes at the Idaho National Engineering Laboratory (INEL). Our results show that this approach may provide an economical means of limiting the intrusion of water on waste sites

  18. Tensile Residual Stress Mitigation Using Low Temperature Phase Transformation Filler Wire in Welded Armor Plates

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [ORNL; Bunn, Jeffrey R [ORNL; Tzelepis, Demetrios A [ORNL; Payzant, E Andrew [ORNL; Yu, Xinghua [ORNL

    2016-01-01

    Hydrogen induced cracking (HIC) has been a persistent issue in welding of high-strength steels. Mitigating residual stresses is one of the most efficient ways to control HIC. The current study develops a proactive in-process weld residual stress mitigation technique, which manipulates the thermal expansion and contraction sequence in the weldments during welding process. When the steel weld is cooled after welding, martensitic transformation will occur at a temperature below 400 C. Volume expansion in the weld due to the martensitic transformation will reduce tensile stresses in the weld and heat affected zone and in some cases produce compressive residual stresses in the weld. Based on this concept, a customized filler wire which undergoes a martensitic phase transformation during cooling was developed. The new filler wire shows significant improvement in terms of reducing the tendency of HIC in high strength steels. Bulk residual stress mapping using neutron diffraction revealed reduced tensile and compressive residual stresses in the welds made by the new filler wire.

  19. iTRAQ-Based Quantitative Proteomic Analysis of Spirulina platensis in Response to Low Temperature Stress.

    Science.gov (United States)

    Li, Qingye; Chang, Rong; Sun, Yijun; Li, Bosheng

    2016-01-01

    Low temperature (LT) is one of the most important abiotic stresses that can significantly reduce crop yield. To gain insight into how Spirulina responds to LT stress, comprehensive physiological and proteomic analyses were conducted in this study. Significant decreases in growth and pigment levels as well as excessive accumulation of compatible osmolytes were observed in response to LT stress. An isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomics approach was used to identify changes in protein abundance in Spirulina under LT. A total of 3,782 proteins were identified, of which 1,062 showed differential expression. Bioinformatics analysis indicated that differentially expressed proteins that were enriched in photosynthesis, carbohydrate metabolism, amino acid biosynthesis, and translation are important for the maintenance of cellular homeostasis and metabolic balance in Spirulina when subjected to LT stress. The up-regulation of proteins involved in gluconeogenesis, starch and sucrose metabolism, and amino acid biosynthesis served as coping mechanisms of Spirulina in response to LT stress. Moreover, the down-regulated expression of proteins involved in glycolysis, TCA cycle, pentose phosphate pathway, photosynthesis, and translation were associated with reduced energy consumption. The findings of the present study allow a better understanding of the response of Spirulina to LT stress and may facilitate in the elucidation of mechanisms underlying LT tolerance.

  20. Temperature stress in accumulation of free proline of pigeonpea seedlings from seeds treated with polyamines

    Directory of Open Access Journals (Sweden)

    Jéssica da Silva

    2015-02-01

    Full Text Available It was studied the effects of seed treatment with polyamines of pigeonpea for proline content of seedling in order to verify that the application of these polyamines attenuates temperature stress on germination and early seedling growth, and see if exogenous putrescine and spermidine induce the accumulation of proline, this amino acid may be biochemical and physiological indicator in seedlings that are under suboptimal temperatures and supraoptmail. The seeds of pigeonpea cv. BRS Mandarin and cv. Caqui, treated with a solution of 0.5 mM of putrescine and spermidine, were subjected to suboptimal temperature (20ºC, 18ºC, 16ºC and 14ºC and supraoptimal (36ºC, 38ºC, 40ºC and 44ºC for 24 hours and 48 hours. After these periods, were subjected to 25°C until day 10, when the percentage of seed germination were observed, the proline content of vegetative parts and the dry mass of the seedlings. A completely randomized design in a factorial arrangement was used 3x4x2+3 (solutions with polyamines, temperature stress by cooling/heating, time of exposure to stress, plus additional factors em25ºC with 0.0 mM and 0.5mM of Put and Spd, with four replicates of 25 seeds. The results were submitted to analysis of variance and means were compared by Tukey test at 5% probability, separately for each cultivar. Both exogenous polyamines attenuate the effects of cooling and heating, contributing to the growth of germinated seeds. Also, putrescine and spermidine exogenous mitigated the adverse effects by inducing proline accumulation, which leads to osmotic adjustment temperatures, although this physiological response has not minimized the negative effects of temperature stress on seedling growth of pigeonpea. Proline can be considered biochemical and physiological indicator in seedlings of both cultivars of pigeonpea treated with polyamines under temperature stress.

  1. Effects of stress temperatures of germination on polyamine titers of soybean seeds

    Science.gov (United States)

    Pineda-Mejia, Renan

    High and low stress temperatures during seed germination and seedling development limit total germination and the rate of germination and growth. Changes in polyamine (PA) concentrations in seeds of different species have been associated with germination, growth and environmental stresses such as temperature, drought, oxygen, chilling injury and osmotic conditions. Two studies were conducted to determine the effect of stress temperatures during germination and seedling development on polyamine titers in soybean seeds. Three germination temperatures, 25, 30, and 36°C were used in the first study to evaluate their influence on changes in polyamine concentrations in soybean seeds germinated at 76 and 90 hours. The polyamines (PAs), cadaverine (Cad), putrescine (Put), spermidine (Spd), agmatine (Agm), and spermine (Spin) were quantified by HPLC using a cation exchange column and an electrochemical detector. Cad, Put, Agm, and Spd declined as the germination temperatures increased from 25 to 36°C. Conversely, Spin increased considerably with an increase in temperature. Total germination was reduced from 97.2 to 92.5% as germination temperatures increased from 25 to 36°C. Germination time did not affect Cad, Agm and Spm, and total germination, however, the interaction between temperature and germination time for Put and Spd concentrations was significant. In the second study, changes in PA concentrations, seedling growth, germination time (t50), fresh and dry weight, and moisture content were measured in the embryonic axis and cotyledons of soybean seeds germinated at 10 and 25°C through six stages of germination dry seed (DS), testa split (TS), radicle at 10 mm (Ra-10), root hairs visible (RHV), secondary root primordia (SRP), and complete seedling (CS). The concentrations of Cad and Put in the embryonic axis, were significantly higher in seeds germinated under low temperature than in seeds at 25°C (approximately 10 and 3 fold respectively). However, this

  2. Burial of a Man-At-Arms in Kudash I Burial Ground

    Directory of Open Access Journals (Sweden)

    Kazantseva Olga A.

    2017-07-01

    Full Text Available The article features a comprehensive analysis of items discovered in male burial 160 of Kudash I burial ground – a unique source of materials for the research of interactions between the local and foreign population on the Middle Kama region in 3rd – 5th centuries A.D. The monument is located in Bardymsky district of Perm Krai. The complex of metal objects comprises a set of personal protective armament rarely discovered in the Kama region: an open-work helmet, a set of plate armour, a sword, a spear head, a knife and "crooked scythes". The article contains a description of the grave, its structure, morphology and classification of findings, as well as the results of an investigation of the manufacturing technology of the following armament and implements: sword, spear head, knife, and "crooked scythe" conducted using the metallographic method. It also features a graphical reconstruction of the warriors’s protective armament – the helmet. The authors determined counterparts of the grave complex discovered at archaeological sites in the Middle Kama region and the Altai Mountains. The apparel of the man-at-arms represents a unique set of protective and offensive armament. The armour of the deceased is complemented by an open-work ceremonial helmet with an aventail, which suggests that the grave belonged to a military commander. The date of burial was determined on the basis of artefact study results as late 4th – early 5th centuries A.D.

  3. valuation of Germination Characteristics for Hedysarum Criniferum Boiss in Alternative Temperature and Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    A. Shahbazi

    2016-05-01

    24-26 °C day-night and four drought levels (0, -2, -4, and -6 bar with three replications. According to the results, different levels of drought stress and alternative temperature had significant effects on germination percentage and germination speed of the species seeds (α=5%. The study showed that increasing temperature and drought levels leads to reducing the germination percentage and germination speed of the species. Higher germination percentage of H. criniferum seeds in different drought levels compared to alternative temperature levels of 24-26 °C indicated that this species is more sensitive to higher temperature than high levels of drought condition. Therefore, it could partly be concluded that the H. criniferum is a relatively drought resistance species.

  4. Effect of heat treatment conditions on stress corrosion cracking resistance of alloy X-750 in high temperature water

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Onimura, Kichiro; Sakamoto, Naruo; Sasaguri, Nobuya; Susukida, Hiroshi; Nakata, Hidenori.

    1984-01-01

    In order to improve the resistance of the Alloy X-750 in high temperature and high purity water, the authors investigated the influence of heat treatment condition on the stress corrosion cracking resistance of the alloy. This paper describes results of the stress corrosion cracking test and some discussion on the mechanism of the stress corrosion cracking of Alloy X-750 in deaerated high temperature water. The following results were obtained. (1) The stress corrosion cracking resistance of Alloy X-750 in deaerated high temperature water remarkably depended upon the heat treatment condition. The materials solution heat treated and aged within temperature ranges from 1065 to 1100 0 C and from 704 to 732 0 C, respectively, have a good resistance to the stress corrosion cracking in deaerated high temperature water. Especially, water cooling after the solution heat treatment gives an excellent resistance to the stress corrosion cracking in deaerated high temperature water. (2) Any correlations were not observed between the stress corrosion cracking susceptibility of Alloy X-750 in deaerated high temperature water and grain boundary chromium depleted zones, precipitate free zones and the grain boundary segregation of impurity elements and so on. It appears that there are good correlations between the stress corrosion cracking resistance of the alloy in the environment and the kinds, morphology and coherency of precipitates along the grain boundaries. (author)

  5. Effects of Temperature Stresses on the Resistance of Chickpea Genotypes and Aggressiveness of Didymella rabiei Isolates

    Directory of Open Access Journals (Sweden)

    Seid Ahmed Kemal

    2017-09-01

    Full Text Available Chickpea (Cicer arietinum L. is an important food and rotation crop in many parts of the world. Cold (freezing and chilling temperatures and Ascochyta blight (Didymella rabiei are the major constraints in chickpea production. The effects of temperature stresses on chickpea susceptibility and pathogen aggressiveness are not well documented in the Cicer-Didymella pathosystem. Two experiments were conducted under controlled conditions using chickpea genotypes and pathogen isolates in 2011 and 2012. In Experiment 1, four isolates of D. rabiei (AR-01, AR-02, AR-03 and AR-04, six chickpea genotypes (Ghab-1, Ghab-2, Ghab-3, Ghab-4, Ghab-5 and ICC-12004 and four temperature regimes (10, 15, 20, and 25°C were studied using 10 day-old seedlings. In Experiment 2, three chickpea genotypes (Ghab-1, Ghab-2, and ICC-12004 were exposed to 5 and 10 days of chilling temperature exposure at 5°C and non-exposed seedlings were used as controls. Seedlings of the three chickpea genotypes were inoculated with the four pathogen isolates used in Experiment 1. Three disease parameters (incubation period, latent period and disease severity were measured to evaluate treatment effects. In Experiment 1, highly significant interactions between genotypes and isolates; genotypes and temperature; and isolate and temperature were observed for incubation and latent periods. Genotype x isolate and temperature x isolate interactions also significantly affected disease severity. The resistant genotype ICC-12004 showed long incubation and latent periods and low disease severity at all temperatures. The highly aggressive isolate AR-04 caused symptoms, produced pycnidia in short duration as well as high disease severity across temperature regimes, which indicated it is adapted to a wide range of temperatures. Short incubation and latent periods and high disease severity were observed on genotypes exposed to chilling temperature. Our findings showed that the significant interactions of

  6. Functional conservation analysis and expression modes of grape anthocyanin synthesis genes responsive to low temperature stress.

    Science.gov (United States)

    Zhang, Cheng; Jia, Haifeng; Wu, Weimin; Wang, Xicheng; Fang, Jinggui; Wang, Chen

    2015-12-10

    In grape cultivation, low temperature generally increases the expression of genes involved in synthesis of anthocyanin. In this study, multi-type structural analysis of the proteins encoded by five anthocyanin biosynthesis genes VvF3H, VvPAL, VvCHS3, VvCHS2 and VvLDOX, in addition to nine of their homologous genes revealed that proteins in grapevine shared a high similarity with that in kiwi, red orange and some other species in which the biosynthesis of anthocyanin significantly influenced by low temperature as proved by previous studies. Low temperature regulatory elements were also found in the promoter region of the grapevine genes VvCHS2, VvPAL and VvF3H. These findings indicate that the functions of anthocyanin biosynthesis genes in grapevine are conservative and might be sensitive to low temperature. In order to identify the specific expression patterns of the five anthocyanin biosynthesis genes and the changes of polyphenols, anthocyanins and flavonoids under low temperature stress. The transcription analysis of the five genes and the content of polyphenols, anthocyanins and flavonoids in grape skins were examined, by using Vitis vinifera L. cv. 'Yongyou 1' and 'Juxing' berries as experimental material and treated at 4°C and 25°C for 24h, 48 h, 72 h and 96 h. The results showed that low temperature greatly enhanced the expression of the five anthocyanin biosynthesis genes. Low temperature greatly slowed down the decomposition of polyphenol, anthocyanin, and flavonoid in grape skins. Our study also found that cv. 'Juxing' responded more sensitively to low temperature than cv. 'Yongyou 1'. All the findings would provide a basis for further study on the mechanism of anthocyanin biosynthesis under environmental stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Neglecting rice milling yield and quality underestimates economic losses from high-temperature stress.

    Directory of Open Access Journals (Sweden)

    Nathaniel B Lyman

    Full Text Available Future increases in global surface temperature threaten those worldwide who depend on rice production for their livelihoods and food security. Past analyses of high-temperature stress on rice production have focused on paddy yield and have failed to account for the detrimental impact of high temperatures on milling quality outcomes, which ultimately determine edible (marketable rice yield and market value. Using genotype specific rice yield and milling quality data on six common rice varieties from Arkansas, USA, combined with on-site, half-hourly and daily temperature observations, we show a nonlinear effect of high-temperature stress exposure on yield and milling quality. A 1 °C increase in average growing season temperature reduces paddy yield by 6.2%, total milled rice yield by 7.1% to 8.0%, head rice yield by 9.0% to 13.8%, and total milling revenue by 8.1% to 11.0%, across genotypes. Our results indicate that failure to account for changes in milling quality leads to understatement of the impacts of high temperatures on rice production outcomes. These dramatic losses result from reduced paddy yield and increased percentages of chalky and broken kernels, which together decrease the quantity and market value of milled rice. Recently published estimates show paddy yield reductions of up to 10% across the major rice-producing regions of South and Southeast Asia due to rising temperatures. The results of our study suggest that the often-cited 10% figure underestimates the economic implications of climate change for rice producers, thus potentially threatening future food security for global rice producers and consumers.

  8. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    Directory of Open Access Journals (Sweden)

    Kolby J. Jardine

    2015-09-01

    Full Text Available Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  9. Fuelling of TCA cycle in hepatic cells Marwari goat during ambient temperature associated stress

    Directory of Open Access Journals (Sweden)

    Kataria N.

    2010-11-01

    Full Text Available The present study was launched to assess the effect of extreme ambient temperature associated stress on fuelling of TCA cycle in hepatic cells of Marwari goat. Based on the fact that whenever a hepatocyte needs fuel for TCA cycle, the activity of enzyme glutamate dehydrogenase (GD increases making alpha-ketoglutarate available for TCA cycle, 600 apparently healthy Marwari goats of either sex, between 6 months to 3 years of age were screened and blood samples were collected during moderate, cold and hot ambient temperature periods to determine the serum glutamate dehydrogenase enzyme and glucose concentration. The mean value of serum GD was significantly (p≤0.05 higher during cold and hot ambient temperature periods in comparison to overall moderate mean value. However, the rise was greater in cold (2.20 times than hot ambient temperature (1.19 times. The serum GD activity was higher in male and younger animals. Serum glucose concentration showed a reverse trend as compared to serum GD activity. The results indicated that in cold condition associated stress the fuelling to TCA cycle was more than moderate and hot ambient temperature periods. Serum GD activity was also found related with glucose homeostasis. Further the study has shown that variations in the enzyme levels are not always pathological and while interpreting clinical data, a clinician must consider these variations.

  10. Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Mills

    2009-03-05

    Cast nickel-based superalloys are used for blades in land-based, energy conversion and powerplant applications, as well as in aircraft gas turbines operating at temperatures up to 1100 C, where creep is one of the life-limiting factors. Creep of superalloy single crystals has been extensively studied over the last several decades. Surprisingly, only recently has work focused specifically on the dislocation mechanisms that govern high temperature and low stress creep. Nevertheless, the perpetual goal of better engine efficiency demands that the creep mechanisms operative in this regime be fully understood in order to develop alloys and microstructures with improved high temperature capability. At present, the micro-mechanisms controlling creep before and after rafting (the microstructure evolution typical of high temperature creep) has occurred have yet to be identified and modeled, particularly for [001] oriented single crystals. This crystal orientation is most interesting technologically since it exhibits the highest creep strength. The major goal of the program entitled ''Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals'' (DOE Grant DE-FG02-04ER46137) has been to elucidate these creep mechanisms in cast nickel-based superalloys. We have utilized a combination of detailed microstructure and dislocation substructure analysis combined with the development of a novel phase-field model for microstructure evolution.

  11. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest.

    Science.gov (United States)

    Jardine, Kolby J; Chambers, Jeffrey Q; Holm, Jennifer; Jardine, Angela B; Fontes, Clarissa G; Zorzanelli, Raquel F; Meyers, Kimberly T; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O; Piva, Luani R de O; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O

    2015-09-15

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  12. Metabolic and cellular stress responses of catfish, Horabagrus brachysoma (Günther) acclimated to increasing temperatures.

    Science.gov (United States)

    Dalvi, Rishikesh S; Das, Tilak; Debnath, Dipesh; Yengkokpam, Sona; Baruah, Kartik; Tiwari, Lalchand R; Pal, Asim K

    2017-04-01

    We investigated the metabolic and cellular stress responses in an endemic catfish Horabagrus brachysoma acclimated to ambient (26°C), 31, 33 and 36°C for 30 days. After acclimation, fish were sampled to investigate changes in the levels of blood glucose, tissue glycogen and ascorbic acid, activities of enzymes involved in glycolysis (LDH), citric acid cycle (MDH), gluconeogenesis (FBPase and G6Pase), pentose phosphate pathway (G6PDH), protein metabolism (AST and ALT), phosphate metabolism (ACP and ALP) and energy metabolism (ATPase), and HSP70 levels in various tissues. Acclimation to higher temperatures (33 and 36°C) significantly increased activities of LDH, MDH, ALP, ACP, AST, ALT and ATPase and blood glucose levels, whereas decreased the G6PDH enzyme activity and, tissue glycogen and ascorbic acid. Results indicated an overall increase in the carbohydrate, protein and lipid metabolism implying increased metabolic demands for maintaining homeostasis in fish acclimated to higher temperatures (33 and 36°C). We observed tissue specific response of HSP70 in H. brachysoma, with significant increase in gill and liver at 33 and 36°C, and in brain and muscle at 36°C, enabling cellular protection at higher acclimation temperatures. In conclusion, H. brachysoma adjusted metabolic and cellular responses to withstand increased temperatures, however, these responses suggest that the fish was under stress at 33°C or higher temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Physical robustness of canopy temperature models for crop heat stress simulation across environments and production conditions

    DEFF Research Database (Denmark)

    Webber, Heidi; White, Jeffrey W; Kimball, Bruce

    2018-01-01

    Despite widespread application in studying climate change impacts, most crop models ignore complex interactions among air temperature, crop and soil water status, CO2 concentration and atmospheric conditions that influence crop canopy temperature. The current study extended previous studies...... between modeling approaches. More accurate simulation of heat stress will likely require use of energy balance approaches that consider atmospheric stability conditions....... by evaluating Tc simulations from nine crop models at six locations across environmental and production conditions. Each crop model implemented one of an empirical (EMP), an energy balance assuming neutral stability (EBN) or an energy balance correcting for atmospheric stability conditions (EBSC) approach...

  14. Analysis technology on the temperature and thermal stress of the cask for radioactive material transport

    International Nuclear Information System (INIS)

    Shin, L.Y.; Jin, C.Y.; Soo, K.H.; Hwan, C.S.

    2005-01-01

    The cask is used to transport the radioactive materials. It is required to withstand for the thirty minute under the hypothetical fire accident condition of the 800□. According to development of the computer simulation, finite element analysis is applied to the calculation widely. But finite element method for the hypothetical accident conditions is not established in domestic regulations. In this study, the temperature and thermal stress analysis of KSC-4 cask under 800□ fire condition is conducted using by ANSYS 7.0 code. In order to analyze finite elements, two-dimensional model of KSC-4 cask is used. Symmetric boundary, convection, and radiation condition are applied in the analysis. As the results, maximum temperature and thermal stress of the KSC-4 cask is evaluated. (orig.)

  15. Sulfide Stress Cracking Behavior of a Martensitic Steel Controlled by Tempering Temperature

    Directory of Open Access Journals (Sweden)

    Yu Sun

    2018-03-01

    Full Text Available A medium-carbon Cr–Mo–V martensitic steel was thermally processed by quenching (Q at 890 °C and tempering (T at increasing temperatures from 650 °C to 720 °C and the effect of tempering temperature, Tt, on sulfide stress cracking (SSC behaviors was estimated mainly via double cantilever beam (DCB and electrochemical hydrogen permeation (EHP tests and microstructure characterization. The results indicate that the threshold stress intensity factor for SSC, KISSC, increased with increasing Tt. The overall and local H concentration around the inclusions decreased with increasing Tt, due to reductions in the amounts of solute atoms, grain boundaries and dislocations, which effectively prevented SSC initiation. Also, increasing Tt caused an increased fraction of high-angle boundaries, which evidently lowered the SSC propagation rate by more frequently diverting the propagating direction and accordingly restricted SSC propagation. The overall SSC resistance of this Q&T–treated steel was therefore significantly enhanced.

  16. Simulation of Stress-Strain behavior for one-dimensional aluminum samples subjected to high temperature

    DEFF Research Database (Denmark)

    Bellini, Anna; Thorborg, Jesper; Hattel, Jesper

    2004-01-01

    , financed by the EU in frame work 6 and born in collaboration with the automobile and foundry industries, to fill the mentioned gap. Through a systematic analysis of experimental tests, this study aims to develop a powerful predicting tool capable of capturing stress relaxation effects through an adequate...... in literature several programs capable of simulating the entire casting process, i.e. filling, solidification, as well as developed thermomechanical stresses. However, it is common practice in the foundry industry that the results obtained by the simulation of the cast process are "forgotten" during...... the analysis of the next phases, such as heat treatment and life prediction of the cast parts. Because of the lack of numerical program tools capable of predicting the stress-strain behavior of aluminum parts subjected to high temperature, it is indeed normally assumed that at the end of the thermal treatment...

  17. Effects of cyclic stress and temperature on oxidation damage of a nickel-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Karabela, A. [Department of Mechanical and Design Engineering, University of Portsmouth, Anglesea Building, Anglesea Road, Portsmouth PO1 3DJ (United Kingdom); Zhao, L.G., E-mail: liguo.zhao@port.ac.uk [Department of Mechanical and Design Engineering, University of Portsmouth, Anglesea Building, Anglesea Road, Portsmouth PO1 3DJ (United Kingdom); Tong, J. [Department of Mechanical and Design Engineering, University of Portsmouth, Anglesea Building, Anglesea Road, Portsmouth PO1 3DJ (United Kingdom); Simms, N.J.; Nicholls, J.R. [School of Applied Sciences, Cranfield University, Cranfield, MK43 0AL (United Kingdom); Hardy, M.C. [Rolls-Royce plc, Elton Road, Derby DE24 8BJ (United Kingdom)

    2011-07-25

    Highlights: {yields} FIB shows the formation of surface oxide scales and internal micro-voids. {yields} Oxidation damage at 800 deg. C is much more severe than that at 700 deg. C and 750 deg. C. {yields} Cyclic stress enhances the extent of oxidation damage at 750 deg. C and above. {yields} Enrichment of Cr and Ti, as well as lower Ni and Co levels, in the surface oxides. {yields} Penetration of oxygen into the material and internal oxidation are evidenced. - Abstract: Oxidation damage, combined with fatigue, is a concern for nickel-based superalloys utilised as disc rotors in high pressure compressor and turbine of aero-engines. A study has been carried out for a nickel-based alloy RR1000, which includes cyclic experiments at selected temperatures (700-800 deg. C) and microscopy examination using focused ion beam (FIB). The results suggest that the major mechanism of oxidation damage consists of the formation of surface oxide scales and internal micro-voids and oxide particles beneath the oxide scales, which become more severe with the increase of temperature. Applying a cyclic stress does not change the nature of oxidation damage but tends to enhance the extent of oxidation damage for temperatures at 750 deg. C and 800 deg. C. The influence of cyclic stress on oxidation damage appears to be insignificant at 700 deg. C, indicating a combined effect of cyclic stress and temperature. Further energy-dispersive X-ray spectrometry (EDXS) analyses show the enrichment of Cr and Ti, together with lower Ni and Co levels, in the surface oxide scales, suggesting the formation of brittle Cr{sub 2}O{sub 3}, TiO{sub 2}, NiO and Co{sub 3}O{sub 4} oxides on the specimen surface. Penetration of oxygen into the material and associated internal oxidation, which leads to further material embrittlement and associated failure, are evidenced from both secondary ion imaging and EDXS analyses.

  18. Analysis of Effective and Internal Cyclic Stress Components in the Inconel Superalloy Fatigued at Elevated Temperature

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Miroslav; Petrenec, Martin; Polák, Jaroslav; Obrtlík, Karel; Chlupová, Alice

    2011-01-01

    Roč. 278, 4 July (2011), s. 393-398 ISSN 1022-6680. [European Symposium on Superalloys and their Application. Wildbad Kreuth, 25.5.2010-28.5.2010] R&D Projects: GA ČR GA106/08/1631 Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloys * high temperature * hysteresis loop * effective and internal stresses Subject RIV: JL - Materials Fatigue, Friction Mechanics; JL - Materials Fatigue, Friction Mechanics (UFM-A)

  19. Evidence for adaptive evolution of low-temperature stress response genes in a Pooideae grass ancestor

    OpenAIRE

    Vigeland, Magnus Dehli; Spannagl, Manuel; Asp, Torben; Paina, Cristiana; Rudi, Heidi; Rognli, Odd Arne; Fjellheim, Siri; Sandve, Simen Rød

    2013-01-01

    Adaptation to temperate environments is common in the grass subfamily Pooideae, suggesting an ancestral origin of cold climate adaptation. Here, we investigated substitution rates of genes involved in low-temperature-induced (LTI) stress responses to test the hypothesis that adaptive molecular evolution of LTI pathway genes was important for Pooideae evolution. Substitution rates and signatures of positive selection were analyzed using 4330 gene trees including three warm climate-adapted spec...

  20. Stress-temperature-lifetime response of nicalon fiber-reinforced SiC composites in air

    International Nuclear Information System (INIS)

    Lin, Hua-Tay; Becher, P.F.

    1996-01-01

    Time-to-failure tests were conducted in four-point flexure and in air as a function of stress levels and temperatures to study the lifetime response of various Nicalon fiber-reinforced SiC (designated as Nic/SiC) composites with a graphitic interfacial coating. The results indicated that all of the Nic/SiC composites exhibit a similar stress-dependent failure at applied stress greater than a threshold value. In this case, the lifetimes of the composites increased with decrease in both stress level and test temperature. The lifetime of the composites appeared to be relatively insensitive to the thickness of graphitic interface layer and was enhanced somewhat by the addition of oxidation inhibitors. Electron microscopy and oxidation studies indicated that the life of the Nic/SiC composites was governed by the oxidation of the graphitic interfaces and the on of glass(es) in composites due to the oxidation of the fiber and matrix, inhibitor phases

  1. Effects of metallurgical factors on stress corrosion cracking of Ni-base alloys in high temperature water

    International Nuclear Information System (INIS)

    Yonezawa, T.; Sasaguri, N.; Onimura, K.

    1988-01-01

    Nickel-base Alloy 600 is the principal material used for the steam generator tubes of PWRs. Generally, this alloy has been proven to be satisfactory for this application, however when it is subjected to extremely high stress level in PWR primary water, it may suffer from stress corrosion cracking. The authors have systematically studied the effects of test temperature and such metallurgical factors as cold working, chemical composition and heat treatment on the stress corrosion cracking of Alloy 600 in high temperature water, and also on that of Alloy 690 which is a promising material for the tubes and may provide improved crrosion resistance for steam generators. The test materials, the stress corrosion cracking test and the test results are reported. When the test temperature was raise, the stress corrosion cracking of the nickel-base alloys was accelerated. The time of stress corrosion cracking occurrence decreased with increasing applied stress, and it occurred at the stress level higher than the 0.2 % offset proof stress of Alloy 600. In Alloy 690, stress corrosion cracking was not observed at such stress level. Cold worked Alloy 600 showed higher resistance to stress corrosion cracking than the annealed alloy. (Kako, I.)

  2. Pengaruh Temperatur Sensitisasi Dan Variasi Stress Terhadap Laju Korosi SS 409 Pada Lingkungan Salt Spray

    Directory of Open Access Journals (Sweden)

    Faris Hizrian Maulana

    2015-03-01

    Full Text Available Korosi intergranular merupakan permasalahan yang sering terjadi pada stainless steel. Hal ini dipicu karena adanya proses sensitisasi yang menyebabkan terbentuk presipitasi karbida pada batas butir yang menyebabkan berkurangnya kadar Cr pada butir yang berakibat stainless steel menjadi rentan terhadap korosi. Ferritic stainless steel 409 merupakan material yang biasa digunakan pada heat exchanger maupun exhaust pada kendaraan otomotif dimana sering mendapatkan temperatur yang tinggi. Jika terdapat internal stress yang merupakan hasil welding maupun cold working pada material tersebut dapat menyebabkan laju korosi menjadi lebih tinggi. Penelitian ini bertujuan mempelajari laju korosi pada spesimen ferritic stainless steel tipe 409 yang telah mengalami proses sensitisasi serta mendapatkan tegangan aplikasi sebesar 20% dan 40% yield stress pada lingkungan salt spray. Hasil SEM menunjukkan adanya senyawa TiC yang merupakan presipitat karbida yang muncul pada spesimen dengan temperatur anil 550oC sampai 850oC yang menyebabkan laju korosi yang lebih tinggi dari spesimen lain. Pengujian ini menunjukkan bahwa semakin tinggi temperatur sensitisasi dan semakin besar stress yang diberikan, laju korosi akan semakin meningkat

  3. Temperature induced stress influence on biodiesel productivity during mixotrophic microalgae cultivation with wastewater.

    Science.gov (United States)

    Venkata Subhash, G; Rohit, M V; Devi, M Prathima; Swamy, Y V; Venkata Mohan, S

    2014-10-01

    The role of operating temperature as a physical stress factor for enhancing lipid induction during microalgae cultivation with domestic wastewater was evaluated. Experiments were designed with dual mode microalgae cultivation viz., growth phase (GP) and temperature induced stress phase (25 °C, 30 °C and 35 °C). GP showed enhancement in biomass growth and carbohydrate accumulation while stress phase (SP) operation at 30 °C showed noticeable improvement in lipid productivities (total/neutral lipid, 24.5/10.2%). Maximum carbohydrate utilization was observed during SP at 30 °C operation (57.8%) compared to 25 °C (50.6%) and 35 °C (26.9%) correlating well with the lipid synthesis. Interestingly the neutral lipid content documented five-fold increment illustrating feasibility towards good biodiesel properties. Biodiesel profile at 30 °C temperature is well supported by higher saturated fatty acids (SFA) to unsaturated fatty acids (USFA) ratio. GP operation showed good COD and nutrient removal concomitant to the biomass growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Correlation between Low Temperature Adaptation and Oxidative Stress in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Estéfani García-Rios

    2016-08-01

    Full Text Available Many factors, such as must composition, juice clarification, fermentation temperature or inoculated yeast strain, strongly affect the alcoholic fermentation and aromatic profile of wine. As fermentation temperature is effectively controlled by the wine industry, low-temperature fermentation (10-15 ºC is becoming more prevalent in order to produce white and rosé wines with more pronounced aromatic profiles. Elucidating the response to cold in Saccharomyces cerevisiae is of paramount importance for the selection or genetic improvement of wine strains. Previous research has shown the strong implication of oxidative stress response in adaptation to low temperature during the fermentation process. Here we aimed first to quantify the correlation between recovery after shock with different oxidants and cold, and then to detect the key genes involved in cold adaptation that belong to sulfur assimilation, peroxiredoxins, glutathione-glutaredoxins and thioredoxins pathways. To do so, we analyzed the growth of knockouts from the EUROSCARF collection S. cerevisiae BY4743 strain at low and optimal temperatures. The growth rate of these knockouts, compared with the control, enabled us to identify the genes involved, which were also deleted and validated as key genes in the background of two commercial wine strains with a divergent phenotype in their low-temperature growth. We identified three genes, AHP1, MUP1 and URM1, whose deletion strongly impaired low-temperature growth.

  5. Physiological and Proteomic Investigations to Study the Response of Tomato Graft Unions under Temperature Stress.

    Science.gov (United States)

    Muneer, Sowbiya; Ko, Chung Ho; Wei, Hao; Chen, Yuze; Jeong, Byoung Ryong

    2016-01-01

    Grafting is an established practice for asexual propagation in horticultural and agricultural crops. The study on graft unions has become of interest for horticulturists using proteomic and genomic techniques to observe transfer of genetic material and signal transduction pathways from root to shoot and shoot to root. Another reason to study the graft unions was potentially to observe resistance against abiotic stresses. Using physiological and proteomic analyses, we investigated graft unions (rootstock and scions) of tomato genotypes exposed to standard-normal (23/23 and 25/18°C day/night) and high-low temperatures (30/15°C day/night). Graft unions had varied responses to the diverse temperatures. High-low temperature, but not standard-normal temperature, induced the production of reactive oxygen species (ROS) in the form of H2O2 and O2-1 in rootstock and scions. However, the expression of many cell protection molecules was also induced, including antioxidant enzymes and their immunoblots, which also show an increase in their activities such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The graft interfaces thus actively defend against stress by modifying their physiological and proteomic responses to establish a new cellular homeostasis. As a result, many proteins for cellular defense were regulated in graft unions under diverse temperature, in addition to the regulation of photosynthetic proteins, ion binding/transport proteins, and protein synthesis. Moreover, biomass, hardness, and vascular transport activity were evaluated to investigate the basic connectivity between rootstock and scions. Our study provides physiological evidence of the grafted plants' response to diverse temperature. Most notably, our study provides novel insight into the mechanisms used to adapt the diverse temperature in graft unions (rootstock/scion).

  6. Physiological and Proteomic Investigations to Study the Response of Tomato Graft Unions under Temperature Stress.

    Directory of Open Access Journals (Sweden)

    Sowbiya Muneer

    Full Text Available Grafting is an established practice for asexual propagation in horticultural and agricultural crops. The study on graft unions has become of interest for horticulturists using proteomic and genomic techniques to observe transfer of genetic material and signal transduction pathways from root to shoot and shoot to root. Another reason to study the graft unions was potentially to observe resistance against abiotic stresses. Using physiological and proteomic analyses, we investigated graft unions (rootstock and scions of tomato genotypes exposed to standard-normal (23/23 and 25/18°C day/night and high-low temperatures (30/15°C day/night.Graft unions had varied responses to the diverse temperatures. High-low temperature, but not standard-normal temperature, induced the production of reactive oxygen species (ROS in the form of H2O2 and O2-1 in rootstock and scions. However, the expression of many cell protection molecules was also induced, including antioxidant enzymes and their immunoblots, which also show an increase in their activities such as superoxide dismutase (SOD, catalase (CAT, and ascorbate peroxidase (APX. The graft interfaces thus actively defend against stress by modifying their physiological and proteomic responses to establish a new cellular homeostasis. As a result, many proteins for cellular defense were regulated in graft unions under diverse temperature, in addition to the regulation of photosynthetic proteins, ion binding/transport proteins, and protein synthesis. Moreover, biomass, hardness, and vascular transport activity were evaluated to investigate the basic connectivity between rootstock and scions.Our study provides physiological evidence of the grafted plants' response to diverse temperature. Most notably, our study provides novel insight into the mechanisms used to adapt the diverse temperature in graft unions (rootstock/scion.

  7. Heat stress and recovery of photosystem II efficiency in wheat (Triticum aestivum L.) cultivars acclimated to different growth temperatures

    DEFF Research Database (Denmark)

    Haque, Sabibul; Kjær, Katrine Heinsvig; Rosenqvist, Eva

    2014-01-01

    The effect of heat stress on photosystem II (PS II) efficiency and post-stress recovery was studied in four wheat cultivars using chlorophyll fluorescence. The main aim was to examine the cultivar differences in relation to inhibition and recovery of PSII functionality after heat stress...... at different growth stages. The secondary aim was to investigate whether a pre-acclimation of plants to elevated temperature during the growth period induces a better tolerance to heat stress than for plants grown in ambient temperature or not. The plants were grown in two growth temperature conditions (15 °C...... and 25 °C) and subjected to heat stress (40 °C) for two days at early tillering and three days at anthesis and early grain development stages. The plants were returned to their original growth conditions after heat stress and recovery was observed for three days. The maximum photochemical efficiency (Fv...

  8. Identification and Tracing Groundwater Contamination by Livestock Burial Sites

    Science.gov (United States)

    Ko, K.; Ha, K.; Park, S.; Kim, Y.; Lee, K.

    2011-12-01

    Foot-and-mouth disease (FMD) or hoof-and-mouth disease is a severe plague for animal farming that affects cloven-hoofed animals such as cattle, pigs, sheep, and goats. Since it is highly infectious and can be easily proliferated by infected animals, contaminated equipments, vehicles, clothing, people, and predators. It is widely known that the virus responsible for FMD is a picornavirus, the prototypic member of the genus Aphthovirus. A serious outbreak of foot-and-mouth disease, leading to the stamping out of 3.53 millions of pigs and cattle and the construction of 4,538 burial sites until 15th March, 2011. The build-up of carcass burial should inevitably produce leachate by the decomposition of buried livestock affecting the surround environment such as air, soil, groundwater, and surface water. The most important issues which are currently raised by scientists are groundwater contamination by leachate from the livestock burial sites. This study examined the current status of FMD outbreak occurred in 2010-2011 and the issues of groundwater contamination by leachate from livestock burial sites. The hydrogeochemical, geophysical, and hydrogeological studies were executed to identify and trace groundwater contamination by leachate from livestock burial sites. Generally livestock mortality leachate contains high concentrations of NH3-N, HCO3-, Cl-, SO42-, K+, Na+, P along with relative lesser amounts of iron, calcium, and magnesium. The groundwater chemical data around four burial sites showed high NH3-N, HCO3-, and K+ suggesting the leachate leakage from burial sites. This is also proved by resistivity monitoring survey and tracer tests. The simulation results of leachate dispersion showed the persistent detrimental impacts for groundwater environment for a long time (~50 years). It is need to remove the leachate of burial sites to prevent the dispersion of leachate from livestock burial to groundwater and to monitor the groundwater quality. The most important

  9. Observations of stress-strain curves of hcp-Fe at high pressures and temperatures

    Science.gov (United States)

    Nishiyama, N.; Wang, Y.; Rivers, M. L.; Sutton, S. R.

    2005-12-01

    We performed in-situ X-ray diffraction and radiography experiments of hcp-Fe within its stability field to observe some independent stress-strain curves of this material. Deformation experiments were carried out at the GSECARS 13-BM-D beamline (APS) using a deformation-DIA with a monochromatic X-ray diffraction and a radiographic imaging system. We used four tungsten carbide and two sintered diamond (SD) anvils with truncated edge length of 2 mm. Pressure medium was a mixture of boron and epoxy and a cylindrical graphite furnace was employed. The starting material is a fragment of pure bcc-Fe wire (0.5 mm in diameter and 0.5 mm long) and two deformation pistons made of alumina were situated above and below the sample. First, the cell assembly was compressed uniformly at room temperature up to about 13 GPa. After that, the sample was heated to about 700 K and we observed transformation of the sample to hcp-Fe. Several deformation cycles were repeated at high pressures and temperatures after the transformation. The incident beam was directed through an anvil-gap and impinged the sample. The diffracted X-rays went through the SD anvils, and thus we were able to observe diffraction Debye rings over the entire 360 degrees detector azimuth range. Two-dimensional diffraction patterns were collected using an X-ray CCD detector. Using distortion of the Debye rings from the true circle and single-crystal elastic moduli of hcp-Fe, differential stresses can be calculated. The sample length was measured by radiography using a wide X-ray beam. Using the radiographic data, axial strains of the sample can be determined. We observed ten independent stress-strain curves with pressures of about 12 GPa, axial strains in excess of 15 percent, three different temperatures, and some strain rates. These stress-strain curves indicate that hcp-Fe deforms elastically at the beginning of deformation. In some of these, we observed saturation of the sample stresses, which means that the

  10. Effects of temperature, temperature gradients, stress, and irradiation on migration of brine inclusions in a salt repository

    International Nuclear Information System (INIS)

    Jenks, G.H.

    1979-07-01

    Available experimental and theoretical information on brine migration in bedded salt are reviewed and analyzed. The effects of temperature, thermal gradients, stress, irradiation, and pressure in a salt repository are among the factors considered. The theoretical and experimental (with KCl) results of Anthony and Cline were used to correlate and explain the available data for rates of brine migration at temperatures up to 250 0 C in naturally occurring crystals of bedded salt from Lyons and Hutchinson, Kansas. Considerations of the effects of stressing crystals of bedded salt on the migratin properties of brine inclusions within the crystals led to the conclusion that the most probable effects are a small fractional increase in the solubility of the salt within the liquid and a concomitant and equal fractional increase in the rate of the thermal gradient-induced migration of the brine. The greatest uncertainty relative to the prediction of rates of migration of brine into a waste emplacement cavity in bedded salt is associated with questions concerning the effects of the grain boundaries (within the aggregates of single crystals which comprise a bedded salt deposit) on brine migration through the deposit. The results of some of the estimates of rates and total amounts of brine inflow to HLW and SURF waste packages emplaced in bedded salt were included to illustrate the inflow volumes which might occur in a repository. The results of the brine inflow estimates for 10-year-old HLW emplaced at 150 kW/acre indicated inflow rates starting at 0.7 liter/year and totaling 12 liters at 30 years after emplacement. The results of the estimates for 10-year-old PWR SURF emplaced at 60 kW/acre indicated a constant inflow of 0.035 liter/year for the first 35 years after emplacement

  11. Theory of Time-Temperature-Stress Equivalent Principle Based on Schapery Equation and Its Application on Granite

    Directory of Open Access Journals (Sweden)

    Yuanguang ZHU

    2014-12-01

    Full Text Available The time-temperature-stress equivalent (TTSE principle refers to the phenomenon that the time-dependent mechanical properties of materials rely on the variations of temperature and stress level. Thus, it is reasonable to predict the long time material mechanical properties based on their relationships with rising temperatures and stress levels. According to the single-integral nonlinear constitutive equation proposed by Schapery, a general expression of the TTSE principle for nonlinear viscoelastic creep property is deduced. The specific expression for time-temperature-stress shift factor is presented by assuming quadratic polynomial form of the Doolittle formula for the viscosity as a function of free volume. Creep curves of granite at different temperatures and stress levels are introduced, and the validation of applying time-temperature-stress principle to predict the long time creep property of granite is provided. The master curves are generated through vertical shift modification and horizontal shift equivalence of all creep curves, and corresponding coefficients in the shift equations are determined by curve fittings. The results indicate the modified time-temperature-stress equivalent relation is appropriate to predict the long time creep property of granite. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6294

  12. Behaviour of a pre-stressed concrete pressure-vessel subjected to a high temperature gradient

    International Nuclear Information System (INIS)

    Dubois, F.

    1965-01-01

    After a review of the problems presented by pressure-vessels for atomic reactors (shape of the vessel, pressures, openings, foundations, etc.) the advantages of pre-stressed concrete vessels with respect to steel ones are given. The use of pre-stressed concrete vessels however presents many difficulties connected with the properties of concrete. Thus, because of the absence of an exact knowledge of the material, it is necessary to place a sealed layer of steel against the concrete, to have a thermal insulator or a cooling circuit for limiting the deformations and stresses, etc. It follows that the study of the behaviour of pre-stressed concrete and of the vessel subjected- to a high temperature gradient can yield useful information. A one-tenth scale model of a pre-stressed concrete cylindrical vessel without any side openings and without a base has been built. Before giving a description of the tests the authors consider some theoretical aspects concerning 'scale model-actual structure' similitude conditions and the calculation of the thermal and mechanical effects. The pre-stressed concrete model was heated internally by a 'pyrotenax' element and cooled externally by a very strong air current. The concrete was pre-stressed using horizontal and vertical cables held at 80 kg/cm 2 ; the thermal gradient was 160 deg. C. During the various tests, measurements were made of the overall and local deformations, the changes in water content, the elasticity modulus, the stress and creep of the cables and the depths of the cracks. The overall deformations observed are in line with thermal deformation theories and the creep of the cables attained 20 to 30 per cent according to their position relative to the internal surface. The dynamic elasticity modulus decreased by half but the concrete keeps its good mechanical properties. Finally, cracks 8 to 12 cm deep and 2 to 3 mms wide appeared in that part of the concrete which was not pre-stressed. The results obtained make it

  13. Blood Glukose Response of Giant Gouramy (Osphronemus gaouramy, Lac. to the Stress of Environmental Temperature Changes

    Directory of Open Access Journals (Sweden)

    S. Hastuti

    2007-08-01

    Full Text Available This experiment was conducted to investigate blood glucose performance of giant gouramy (Osphronemus gouramy, Lac. to environmental changes. Fish with body weight of about 52,15 g was used in the experiment. A hundred and twenty fish were subjected to stress by moving them to another aquarium containing cooler water for 5 minute before put them back to the origin aquarium. The stress treatments were Δ 0°C (A, Δ-3°C (B, Δ-6°C(C, and Δ-9°C(D. Blood glucose was measured at 0, 1, 2, 3, 4 and 5 hours post stress, each for 5 fish. During stress treatment, the survival offish were recorded. To study the role of insulin activation on reducing the stress effects, thirty fish were injected with insulin 2 IU/100 g body weight before subjected them to stressar. Blood glucose level of fish subjected to temperature stress of Δ-9°C was the greatest. The blood glucose response to temperature changes was linear, Y = 4,4543 X + 35,553 with R2 = 0,09976. The survival rate of fish was 100% for all treatments. Injected of insulin 2 IU/100 g body weight was able to reduce hyperglycemia that caused by stress. Key words: Blood glucose, giant gouramy, Osphronemus gouramy, stress   ABSTRAK Penelitian ini dilakukan dengan tujuan untuk mengetahui performa glukosa darah ikan gurami (Osphronemus gouramy, Lac. dalam merespon perubahan suhu lingkungan. Ikan berbobot rata-rata 52,15 g sebanyak 120 ekor diberi stres dengan cara diangkat dan dipindahkan ke suatu wadah yang bersuhu lebih dingin selama 5 menit dan dikembalikan lagi ke wadah mula-mula. Perlakuan stres perubahan suhu dingin tersebut adalah A (Δ 0°C, B (Δ- 3°C, C (Δ-6°C dan D (Δ-9°C. Glukosa darah diukur dari 5 ekor ikan pada jam ke 0, 1, 2, 3, 4 dan 5 jam pascastres. Kelangsungan hidup dihitung pada saat perlakuan stres. Untuk melihat peran aktivasi insulin dalam menekan efek stres, ikan sebanyak 30 ekor diinjeksi insulin 2 iu/100 g bobot badan sebelum diberi stres. Kadar glukosa darah ikan gurame

  14. Low-Temperature Stress during Capped Brood Stage Increases Pupal Mortality, Misorientation and Adult Mortality in Honey Bees

    Science.gov (United States)

    Wang, Qing; Xu, Xinjian; Zhu, Xiangjie; Chen, Lin; Zhou, Shujing; Huang, Zachary Y.; Zhou, Bingfeng

    2016-01-01

    Honey bees (Apis mellifera) are key pollinators, playing a vital role in ecosystem maintenance and stability of crop yields. Recently, reduced honey bee survival has attracted intensive attention. Among all other honey bee stresses, temperature is a fundamental ecological factor that has been shown to affect honey bee survival. Yet, the impact of low temperature stress during capped brood on brood mortality has not been systematically investigated. In addition, little was known about how low temperature exposure during capped brood affects subsequent adult longevity. In this study, capped worker broods at 12 different developmental stages were exposed to 20°C for 12, 24, 36, 48, 60, 72, 84 and 96 hours, followed by incubation at 35°C until emergence. We found that longer durations of low temperature during capped brood led to higher mortality, higher incidences of misorientation inside cells and shorter worker longevity. Capped brood as prepupae and near emergence were more sensitive to low-temperature exposure, while capped larvae and mid-pupal stages showed the highest resistance to low-temperature stress. Our results suggest that prepupae and pupae prior to eclosion are the most sensitive stages to low temperature stress, as they are to other stresses, presumably due to many physiological changes related to metamorphosis happening during these two stages. Understanding how low-temperature stress affects honey bee physiology and longevity can improve honey bee management strategies. PMID:27149383

  15. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    DEFF Research Database (Denmark)

    Chen, Jun; Shen, Jing; Solem, Christian

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed...... riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C....... These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller...

  16. Stress, strain, and temperature induced permeability changes in potential repository rocks

    International Nuclear Information System (INIS)

    Heard, H.C.; Duba, A.

    1977-01-01

    Work is in progress to assess the permeability characteristics of coarse-grained igneous rocks as affected by pressure, deviatoric stress, and temperature. In order to predict the long-term behavior of these rocks, both virgin and fractured, permeability and all principal strains resulting from an imposed deviatoric stress under various simulated lithostatic pressures are being measured. In addition, compressional as well as shear velocities and electrical conductivity are being evaluated along these principal directions. These simultaneous measurements are being made initially at 25 0 C on a 15 cm diameter by 30 cm long sample in a pressure apparatus controlled by a mini-computer. Correlation of these data with similar field observations should then allow simplified exploration for a suitable repository site as well as the prediction of the response of a mined cavity with both distance and time at this site. After emplacement of the waste canisters, the mechanical stability and hydrologic integrity of this mined repository will be directly influenced by the fracturing of the surrounding rock which results from local temperature differences and the thermal expansion of that rock. Temperatures (and, hence, these differences) in the vicinity of the repository are expected to be affected by the presence of pore fluids (single- or two-phase) in the rock, the heat capacity and the thermal conductivity of this system. In turn, these are all dependent upon lithostatic pressure, pore pressure, and stress. Thermal expansion (and fracturing) will also be affected by the lithostatic (and effective) pressure, the deviatoric stress field, and the initial anisotropy of the rock

  17. A study of the effect of apparent strain on thermal stress measurement for two types of elevated temperature strain gages

    Science.gov (United States)

    Jenkins, J. M.

    1983-01-01

    A weldable type strain gage was used to measure low level thermal stress in an elevated temperature environment. Foil strain gages used in a comparative manner reveal that the apparent strain of weldable strain gages is not sufficiently known to acquire accurate low level thermal stress data. Apparent strain data acquired from coupon tests reveals a large scatter in apparent strain characteristics among the weldable strain gages. It is concluded that apparent strain data for individual weldable strain gages must be required prior to installation if valid thermal stress data is to be obtained through the temperature range of room temperature to 755 K (900 F).

  18. Patterns of Irregular Burials in Western Europe (1st-5th Century A.D..

    Directory of Open Access Journals (Sweden)

    Marco Milella

    Full Text Available Irregular burials (IB--burials showing features that contrast with the majority of others in their geographic and chronological context have been the focus of archaeological study because of their relative rarity and enigmatic appearance. Interpretations of IB often refer to supposed fear of the dead or to social processes taking place in time-specific contexts. However, a comprehensive and quantitative analysis of IB for various geographical contexts is still lacking, a fact that hampers any discussion of these burials on a larger scale.Here, we collected a bibliographic dataset of 375 IB from both Britain and Continental Europe, altogether spanning a time period from the 1st to the 5th century AD. Each burial has been coded according to ten dichotomous variables, further analyzed by means of chi-squared tests on absolute frequencies, non-metric multidimensional scaling, and cluster analysis.Even acknowledging the limits of this study, and in particular the bias represented by the available literature, our results point to interesting patterns. Geographically, IB show a contrast between Britain and Continental Europe, possibly related to historical processes specific to these regions. Different types of IB (especially prone depositions and depositions with the cephalic extremity displaced present a series of characteristics and associations between features that permit a more detailed conceptualization of these occurrences from a socio-cultural perspective that aids to elucidate their funerary meaning.Altogether, the present work stresses the variability of IB, and the need to contextualize them in a proper archaeological and historical context. It contributes to the discussion of IB by providing a specific geographic and chronological frame of reference that supports a series of hypotheses about the cultural processes possibly underlying their occurrence.

  19. An experimental analysis of temperature and stress fields in girth welded 304L stainless steel pipes

    International Nuclear Information System (INIS)

    Li, M.; Atteridge, D.G.; Anderson, W.E.; Hubbard, C.R.; Spooner, S.

    1996-01-01

    The thermal and deformation/strain histories were measured by a computer data acquisition system for three 406-mm-diameter, Type 304L stainless steel (SS), schedule 40 (12.7 mm thickness) pipe girth welds. Two welds were standard V groove preparations and completed in six and nine (discontinuous) passes with multiple start-stop positions, while the third one was a narrow groove configuration and finished with four continuous passes with one start-stop position. The thermomechanical history measurements were taken on the pipe inner surface, encompassing the weld centerline (WCL) and heat-affected zone; a total of 47 data acquisition instruments were used for each weld to monitor weld shrinkages, surface temperatures, surface strains, and radial deformations. The experimental data give the following general conclusions: (1) the temperature profiles in the two V groove weldments are, in general, axisymmetric, while the temperature profile in the narrow gap groove weldment is axisymmetric in locations far from WCL, but is not axisymmetric in locations near start-stop position; (2) the strain/deformation histories are controlled by the thermal histories with the final strain/deformation value largely determined by the last one or two passes of welding; (3) the strain/deformation profile in the weldment is not axisymmetric suggesting that the residual stress is not axisymmetrically distributed; (4) the four-pass narrow gap weldment experienced the fewest time and temperature cycles during welding, and has the lowest level of radial deformation among the three pipe weldments indicating that the narrow gap weldment would have the lowest overall residual stress level among the three pipe weldments. Residual stress measurements on the inner surface of four-pass pipe weldment were performed using the neutron diffraction (ND) technique. The ND results show that a tensile zone exists on the pipe inner surface and in the weld and its heat-affected zone (HAZ) area

  20. 25 CFR 20.324 - When can the Bureau provide Burial Assistance?

    Science.gov (United States)

    2010-04-01

    ... ASSISTANCE AND SOCIAL SERVICES PROGRAMS Direct Assistance Burial Assistance § 20.324 When can the Bureau provide Burial Assistance? In the absence of other resources, the Bureau can provide Burial Assistance for... 25 Indians 1 2010-04-01 2010-04-01 false When can the Bureau provide Burial Assistance? 20.324...

  1. Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

    DEFF Research Database (Denmark)

    Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas

    2008-01-01

    . The burial history modelling points to development of most of the dolomite cement during rapid Silurian-Devonian subsidence and Carboniferous-early Permian uplift. A wide range of precipitation temperatures indicate that temperature was not a major factor in triggering the carbonate cementation. Dolomite...... precipitation is related to early stages of organic matter maturation and thus to the oil generation history in the basin. delta C-13 values vary from +0.03% to -6.2%( PDB), suggesting limited addition of carbon from an organic source, with the major part derived from marine bicarbonate. The sourcing of carbon...

  2. Cellular mechanisms contributing to multiple stress tolerance in Saccharomyces cerevisiae strains with potential use in high-temperature ethanol fermentation.

    Science.gov (United States)

    Kitichantaropas, Yasin; Boonchird, Chuenchit; Sugiyama, Minetaka; Kaneko, Yoshinobu; Harashima, Satoshi; Auesukaree, Choowong

    2016-12-01

    High-temperature ethanol fermentation has several benefits including a reduction in cooling cost, minimizing risk of bacterial contamination, and enabling simultaneous saccharification and fermentation. To achieve the efficient ethanol fermentation at high temperature, yeast strain that tolerates to not only high temperature but also the other stresses present during fermentation, e.g., ethanol, osmotic, and oxidative stresses, is indispensable. The C3253, C3751, and C4377 Saccharomyces cerevisiae strains, which have been previously isolated as thermotolerant yeasts, were found to be multiple stress-tolerant. In these strains, continuous expression of heat shock protein genes and intracellular trehalose accumulation were induced in response to stresses causing protein denaturation. Compared to the control strains, these multiple stress-tolerant strains displayed low intracellular reactive oxygen species levels and effective cell wall remodeling upon exposures to almost all stresses tested. In response to simultaneous multi-stress mimicking fermentation stress, cell wall remodeling and redox homeostasis seem to be the primary mechanisms required for protection against cell damage. Moreover, these strains showed better performances of ethanol production than the control strains at both optimal and high temperatures, suggesting their potential use in high-temperature ethanol fermentation.

  3. Bone foreshafts from a clovis burial in southwestern montana.

    Science.gov (United States)

    Lahren, L; Bonnichsen, R

    1974-10-11

    Formal and functional analyses of bone artifacts from a Clovis burial in southwestern Montana suggest that they were constructed to serve as (detachable or nondetachable) foreshafts for attaching fluted projectile points to lance shafts.

  4. Waste migration studies at the Savannah River Plant burial ground

    International Nuclear Information System (INIS)

    Stone, J.A.; Oblath, S.B.; Hawkins, R.H.; Grant, M.W.; Hoeffner, S.L.; King, C.M.

    1985-01-01

    The low-level radioactive waste burial ground at the Savannah River Plant is a typical shallow-land-burial disposal site in a humid region. Studies of waste migration at this site provide generic data for designing other disposal facilities. A program of field, laboratory, and modeling studies for the SRP burial ground has been conducted for several years. Recent results of lysimeter tests, soil-water chemistry studies, and transport modeling are reported. The lysimeter experiments include ongoing tests with 40 lysimeters containing a variety of defense wastes, and recently concluded lysimeter tests with tritium and plutonium waste forms. The tritium lysimeter operated 12 years. In chemistry studies, measurements of soil-water distribution coefficients (K/sub d/) were concluded. Current emphasis is on identification of trace organic compounds in groundwater from the burial site. Development of the dose-to-man model was completed, and the computer code is available for routine use. 16 refs., 2 figs., 2 tabs

  5. Rusenikha Burial Ground: interdisciplinary approach to monument investigation

    Directory of Open Access Journals (Sweden)

    Nikitina Tatyana B.

    2017-07-01

    Full Text Available The article presents the results of excavations at Rusenikha burial ground of Mari culture dating back to the medieval period obtained as a result of bioarcheological research. The research conducted by the authors is based on the atomic-absorption photometry method. Study of mineral composition allowed to classify the burials of Rusenikha burial mound into 2 conventional groups. The bone tissue located in burials of the first group contain exceedingly high concentrations of zinc, copper, lead and manganese with low calcium content, and low to average strontium content. Bones feature average or low mineralization. Of special interest is an individual group of skeletons with high zinc and manganese content, and very low strontium content. The differences determined on the basis of studying the mineral composition of bone tissue have been confirmed by an analysis of archaeological material: planigraphy, funerary rite and item inventory.

  6. Effects of urban stream burial on nitrogen uptake and ...

    Science.gov (United States)

    Urbanization has resulted in extensive burial and channelization of headwater streams, yet little is known about impacts on stream ecosystem functions critical for reducing downstream nitrogen pollution. To characterize the biogeochemical impact of stream burial, we measured NO3- uptake, using 15N-NO3- isotope tracer releases, and whole stream metabolism, during four seasons in three paired buried and open streams reaches within the Baltimore Ecosystem Study Long-term Ecological Research Network. Stream burial increased NO3- uptake lengths, by a factor of 7.5 (p metabolism were primarily explained by decreased transient storage and light availability in buried streams. We estimate that stream burial increases daily watershed nitrate export by as much as 500% due to decreased in-stream retention and may considerably decrease carbon export via decreased primary production. These results

  7. Influence of Mineralogy, Pressure, Temperature and Stress on Mechanical roperties of shale Rocks

    Science.gov (United States)

    Herrmann, J.; Rybacki, E.; Sone, H.; Dresen, G. H.

    2017-12-01

    The production of hydrocarbons from unconventional reservoirs, like tight shale plays increased tremendously over the past decade. Hydraulic fracturing is a common method to increase the productivity of a well drilled in these reservoirs. Unfortunately, the production rate decreases over time presumably due to fracture healing. The healing rate induced by proppant embedment depends on pressure (p), temperature (T), stress (σ) - conditions and on shale composition. To improve understanding of the influence of these parameters on fracture healing, we conducted constant strain rate experiments (p = 50 - 100 MPa, T = 50 - 125 °C, ɛ/t = 5 * 10-4 - 5 * 10-6 s-1) on porous ( 8 %), quartz - rich ( 72 vol %) Bowland shale (UK) and on low porosity ( 3 %), clay - rich ( 33 vol %) Posidonia shale (GER), deformed perpendicular to bedding and with as-is water content. Bowland shale showed mainly brittle behaviour with predominantly elastic deformation before failure and a high strength (280 - 350 MPa). In contrast, Posidonia shale deformed semibrittle with pronounced inelastic deformation and low peak strength (165 - 220 MPa). For both shale rocks, static Young's moduli vary between 12 - 18 GPa. In addition, we performed a series of constant stress tests on both shales at p = 30 - 115 MPa, T = 75 - 150 °C and σ = 160 - 450 MPa. Samples showed transient (primary) creep with increasing strain rates for increasing temperature and stress and decreasing pressure. An empirical power law in the form of ɛ = A*tm is used to describe the observed relation between inelastic strain (ɛ) and time (t), where the constant A is mainly affected by temperature and stress and the exponent m accounts for the influence of pressure. Compared to quartz - rich, strong Bowland shale, the creep behaviour of clay - rich, weak Posidonia shale is much more sensitive to changes in pressure, temperature and stress. Electron microscopy suggests that creep was mainly accommodated by deformation of weak

  8. Numerical Simulation for Thermal Shock Resistance of Ultra-High Temperature Ceramics Considering the Effects of Initial Stress Field

    Directory of Open Access Journals (Sweden)

    Weiguo Li

    2011-01-01

    Full Text Available Taking the hafnium diboride ceramic as an example, the effects of heating rate, cooling rate, thermal shock initial temperature, and external constraint on the thermal shock resistance (TSR of ultra-high temperature ceramics (UHTCs were studied through numerical simulation in this paper. The results show that the external constraint has an approximately linear influence on the critical rupture temperature difference of UHTCs. The external constraint prepares a compressive stress field in the structure because of the predefined temperature field, and this compressive stress field relieves the tension stress in the structure when it is cooled down and then it improves the TSR of UHTCs. As the thermal shock initial temperature, a danger heating rate (or cooling rate exists where the critical temperature difference is the lowest.

  9. Reliability Analysis of Temperature Influence on Stresses in Rigid Pavement Made from Recycled Materials

    Directory of Open Access Journals (Sweden)

    Aleš Florian

    2016-01-01

    Full Text Available Complex statistical and sensitivity analysis of principal stresses in concrete slabs of the real type of rigid pavement made from recycled materials is performed. The pavement is dominantly loaded by the temperature field acting on the upper and lower surface of concrete slabs. The computational model of the pavement is designed as a spatial (3D model, is based on a nonlinear variant of the finite element method that respects the structural nonlinearity, enables to model different arrangement of joints, and the entire model can be loaded by thermal load. Four concrete slabs separated by transverse and longitudinal joints and the additional structural layers including soil to the depth of about 3 m are modeled. The thickness of individual layers, physical and mechanical properties of materials, characteristics of joints, and the temperature of the upper and lower surface of slabs are supposed to be random variables. The simulation technique Updated Latin Hypercube Sampling with 20 simulations is used for the reliability analysis. As results of statistical analysis, the estimates of basic statistics of the principal stresses σ1 and σ3 in 106 points on the upper and lower surface of slabs are obtained. For sensitivity analysis the sensitivity coefficient based on the Spearman rank correlation coefficient is used. As results of sensitivity analysis, the estimates of influence of random variability of individual input variables on the random variability of principal stresses σ1 and σ3 are obtained.

  10. Characterization of Flame Cut Heavy Steel: Modeling of Temperature History and Residual Stress Formation

    Science.gov (United States)

    Jokiaho, T.; Laitinen, A.; Santa-aho, S.; Isakov, M.; Peura, P.; Saarinen, T.; Lehtovaara, A.; Vippola, M.

    2017-12-01

    Heavy steel plates are used in demanding applications that require both high strength and hardness. An important step in the production of such components is cutting the plates with a cost-effective thermal cutting method such as flame cutting. Flame cutting is performed with a controlled flame and oxygen jet, which burns the steel and forms a cutting edge. However, the thermal cutting of heavy steel plates causes several problems. A heat-affected zone (HAZ) is generated at the cut edge due to the steep temperature gradient. Consequently, volume changes, hardness variations, and microstructural changes occur in the HAZ. In addition, residual stresses are formed at the cut edge during the process. In the worst case, unsuitable flame cutting practices generate cracks at the cut edge. The flame cutting of thick steel plate was modeled using the commercial finite element software ABAQUS. The results of modeling were verified by X-ray diffraction-based residual stress measurements and microstructural analysis. The model provides several outcomes, such as obtaining more information related to the formation of residual stresses and the temperature history during the flame cutting process. In addition, an extensive series of flame cut samples was designed with the assistance of the model.

  11. Effect of storage temperatures and stresses on the survival of Salmonella spp. in halva.

    Science.gov (United States)

    Osaili, T M; Al-Nabulsi, A A; Nazzal, D S; Shaker, R R

    2017-11-01

    The presence of Salmonella spp. in halva has been associated with foodborne illnesses and product recalls from the markets. This study investigated the effect of environmental stresses on the survival of Salmonella spp. in halva during storage for 12 months at 10 and 25°C (log (N 0 /N) g -1 ). Halva samples were inoculated with a cocktail of four strains of unstressed, desiccation stressed or heat stressed Salmonella (10 6 -10 7  CFU per gram). In general, survival of Salmonella spp. in halva decreased significantly (P ˂ 0·05) as storage time and temperature increased. At the end of halva shelf life at 10°C, the initial populations of unstressed, desiccation stressed or heat stressed Salmonella spp. decreased by 2·7, 2·6 or 2·8 log CFU per gram (reduction rate c. 0·2 log CFU per month), respectively. While at 25°C, the populations decreased 5·2, 6·7 or 6·3 log CFU per gram, respectively (reduction rate c. 0·4-0·5 log CFU per month). The populations of stressed Salmonella spp. in halva samples were not significantly different (P ≥ 0·05) from populations of unstressed cells during storage at 10 and 25°C, except during the last 3 months of storage at 25°C when populations of unstressed cells were higher (P Salmonella spp. to desiccation or heat stress prior product contamination may play a role in Salmonella spp. survival in halva during storage. Contamination of halva (tahini halva) with Salmonella from raw materials or during production was documented. Halva and tahini have been involved in salmonellosis outbreaks in different countries. The study demonstrated enhanced survivability of stressed and unstressed Salmonella spp. in halva over a 12-month storage period at 10 and 25°C with lower log reductions than expected. Exposing Salmonella spp. to desiccation or heat stress prior product contamination may play a role in microbial survival in halva during storage. These findings serve as a model to halva producers to implement control

  12. Time and Temperature Dependence of Viscoelastic Stress Relaxation in Gold and Gold Alloy Thin Films

    Science.gov (United States)

    Mongkolsuttirat, Kittisun

    Radio frequency (RF) switches based on capacitive MicroElectroMechanical System (MEMS) devices have been proposed as replacements for traditional solid-state field effect transistor (FET) devices. However, one of the limitations of the existing capacitive switch designs is long-term reliability. Failure is generally attributed to electrical charging in the capacitor's dielectric layer that creates an attractive electrostatic force between a moving upper capacitor plate (a metal membrane) and the dielectric. This acts as an attractive stiction force between them that may cause the switch to stay permanently in the closed state. The force that is responsible for opening the switch is the elastic restoring force due to stress in the film membrane. If the restoring force decreases over time due to stress relaxation, the tendency for stiction failure behavior will increase. Au films have been shown to exhibit stress relaxation even at room temperature. The stress relaxation observed is a type of viscoelastic behavior that is more significant in thin metal films than in bulk materials. Metal films with a high relaxation resistance would have a lower probability of device failure due to stress relaxation. It has been shown that solid solution and oxide dispersion can strengthen a material without unacceptable decreases in electrical conductivity. In this study, the viscoelastic behavior of Au, AuV solid solution and AuV2O5 dispersion created by DC magnetron sputtering are investigated using the gas pressure bulge testing technique in the temperature range from 20 to 80°C. The effectiveness of the two strengthening approaches is compared with the pure Au in terms of relaxation modulus and 3 hour modulus decay. The time dependent relaxation curves can be fitted very well with a four-term Prony series model. From the temperature dependence of the terms of the series, activation energies have been deduced to identify the possible dominant relaxation mechanism. The measured

  13. Water problems at the West Valley burial site

    International Nuclear Information System (INIS)

    Kelleher, W.J.

    1979-01-01

    A history of the water problems encountered at the West Valley, New York, burial site is presented with recommendations concerning operation at this site to prevent migration of radioactivity off site. When a permit to bury wastes was first issued in 1963, the possibility of water ponding in trenches because of relatively impermeable soil was recognized. Water rose persistently in 3 completed trenches in the north burial area, so the permit was revised in 1968 to be more explicit on how the trenches should be constructed to minimize the entrance of water into completed trenches. Water has not risen in the 7 trenches in the south burial area, which were completed in accordance with the revised permit. Water continued to rise in the 4 trenches in the north burial area and in early 1975 water from 2 of these trenches began to seep out through the cover. Three of the trenches were pumped to halt this seepage. Monitoring of surface streams has indicated no large-scale migration of radioisotopes away from the burial site. However, extraneous sources of radioactivity made it impossible to detect small amounts of seepage. Soil samples taken in 1973 near the trenches confirmed that there was no large-scale underground migration. The borings did indicate the existence of perched groundwater near the problem trenches in the north burial area that could result in the horizontal migration of water in or out of trenches. The USGS is now making a detailed hydrogeological study of the burial area. Erosion control and prevention of water from entering completed trenches are the main environmental problems at the West Valley burial site

  14. Elevated temperature altered photosynthetic products in wheat seedlings and organic compounds and biological activity in rhizopshere soil under cadmium stress.

    Science.gov (United States)

    Jia, Xia; Zhao, YongHua; Wang, WenKe; He, Yunhua

    2015-09-23

    The objective of this study was to investigate the effects of slightly elevated atmospheric temperature in the spring on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated temperature was associated with increased soluble sugars, reducing sugars, starch, and total sugars, and with decreased amino acids in wheat seedlings under Cd stress. Elevated temperature improved total soluble sugars, free amino acids, soluble phenolic acids, and organic acids in rhizosphere soil under Cd stress. The activity of amylase, phenol oxidase, invertase, β-glucosidase, and l-asparaginase in rhizosphere soil was significantly improved by elevated temperature under Cd stress; while cellulase, neutral phosphatase, and urease activity significantly decreased. Elevated temperature significantly improved bacteria, fungi, actinomycetes, and total microorganisms abundance and fluorescein diacetate activity under Cd stress. In conclusion, slightly elevated atmospheric temperature in the spring improved the carbohydrate levels in wheat seedlings and organic compounds and biological activity in rhizosphere soil under Cd stress in the short term. In addition, elevated atmospheric temperature in the spring stimulated available Cd by affecting pH, DOC, phenolic acids, and organic acids in rhizosphere soil, which resulted in the improvement of the Cd uptake by wheat seedlings.

  15. Study of glass transition temperature (Tg) of novel stress-sensitive composites using molecular dynamic simulation

    Science.gov (United States)

    Koo, B.; Liu, Y.; Zou, J.; Chattopadhyay, A.; Dai, L. L.

    2014-09-01

    This study investigates the glass transition temperature (Tg) of novel stress-sensitive composites capable of detecting a damage precursor using molecular dynamics (MD) simulations. The molecular structures of a cross-linked epoxy network (which consist of epoxy resin, hardener and stress-sensitive material) have been simulated and experimentally validated. The chemical constituents of the molecular structures are di-glycidyl ether of bisphenol F (DGEBF: epoxy resin), di-ethylene tri-amine (DETA: hardener) and tris-(cinnamoyloxymethyl)-ethane (TCE: stress-sensitive material). The cross-linking degree is varied by manipulating the number of covalent bonds through tuning a cutoff distance between activated DGEBF and DETA during the non-equilibrium MD simulation. A relationship between the cross-linking degree and Tgs has been studied numerically. In order to validate a proposed MD simulation framework, MD-predicted Tgs of materials used in this study have been compared to the experimental results obtained by the differential scanning calorimetry (DSC). Two molecular models have been constructed for comparative study: (i) neat epoxy (epoxy resin with hardener) and (ii) smart polymer (neat epoxy with stress-sensitive material). The predicted Tgs show close agreement with the DSC results.

  16. Leaf Water Relationships and Canopy Temperature as Criteria to Distinguish Maize Hybrids under Drought Stress

    Directory of Open Access Journals (Sweden)

    Abbas Maleki

    2014-05-01

    Full Text Available This research aimed at studying the physiologic traits of maize different hybrids and considering them as screening criteria to select the drought tolerant hybrids. The experiment was conducted using a randomized complete block design with three replications and in a split-plot arrangement. The treatments were as follows: Maize Hybrids (including SC400, ZP434, SC524, ZP599, BC66, SC704 and irrigation regimes (including optimum; 100% FC, moderate; 75% FC, and severe stress; 50% FC. Results showed that drought stress significantly affects most of the studied indices. These indices also had significant differences in the above mentioned hybrids. Indices of leaf relative water content and temperature of the canopy varied significantly under drought stress. So, they could be used as suitable criteria to measure the level of stress effect on the plant and also to lay out the irrigation schedule. Findings of the study suggest that blistering is the best growth stage to screen the hybrids and among the studied indices, the ELWL is the best item for screening.

  17. AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions

    Science.gov (United States)

    Wiegand, C. L. (Principal Investigator); Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J.

    1981-01-01

    Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures.

  18. Tritium in the burial ground of the Savannah River Site

    International Nuclear Information System (INIS)

    Hyder, M.L.

    1993-06-01

    This memorandum reviews the available information on tritium-contaminated material discarded to burial grounds. Tritium was the first isotope studied because it represents the most immediate concern with regard to release to the environment. Substantial amounts of tritium are known to be present in the ground water underneath the area, and outcropping of this ground water in springs and seeps has been observed. The response to this release of tritium from the burial ground is a current concern. The amount of tritium emplaced in the burial ground facilities is very uncertain, however, some general conclusions can be made. In particular, most of the tritium buried is associated with spent equipment and other waste, rather than spent melts. Correspondingly, most of the tritium in the ground water seems to be associated with burials of this type, rather than the spent melts. Maps are presented showing the location of burials of tritiated waste by type, and the location of the largest individual burials according to COBRA records

  19. Physiological performance of sesame seeds under the water stress at different temperatures

    Directory of Open Access Journals (Sweden)

    Dayana Silva de Medeiros

    2015-10-01

    Full Text Available Sesame (Sesamum indicum L. shows great economic potential because it can be explored by the national as well as the international market. It can be grown in the second season when it is subject to less favorable weather conditions such as drought during the sowing and emergence. Given this the objective was to evaluate the effect of water stress induced by polyethylene glycol solutions (PEG 6000 at different temperatures in order to asses the physiological quality of sesame seeds. In this work, were used PEG 6000 with different osmotic potentials (0.0 control and (-0.2, –0.4, –0.6, –0.8, –1.0 –1,2 and –1.4 MPa at temperatures of 25, 30 and 35 °C. For determine the effect of the treatments it was evaluated seed germination and vigor (first count and length of the primary root and shoot, in a completely randomized, with four replications. The sesame seeds are affected by water stress, with significant reductions in germination and vigor. A temperature of 30 °C favored the germination performance in less restrictive water potentials.

  20. Ensuring Reproduction at High Temperatures: The Heat Stress Response during Anther and Pollen Development

    Directory of Open Access Journals (Sweden)

    Filomena Giorno

    2013-07-01

    Full Text Available Sexual reproduction in flowering plants is very sensitive to environmental stresses, particularly to thermal insults which frequently occur when plants grow in field conditions in the warm season. Although abnormalities in both male and female reproductive organs due to high temperatures have been described in several crops, the failure to set fruits has mainly been attributed to the high sensitivity of developing anthers and pollen grains, particularly at certain developmental stages. A global view of the molecular mechanisms involved in the response to high temperatures in the male reproductive organs will be presented in this review. In addition, transcriptome and proteomic data, currently available, will be discussed in the light of physiological and metabolic changes occurring during anther and pollen development. A deep understanding of the molecular mechanisms involved in the stress response to high temperatures in flowers and, particularly, in the male reproductive organs will be a major step towards development of effective breeding strategies for high and stable production in crop plants.

  1. Exploring the Metabolomic Responses of Bacillus licheniformis to Temperature Stress by Gas Chromatography/Mass Spectrometry.

    Science.gov (United States)

    Dong, Zixing; Chen, Xiaoling; Cai, Ke; Chen, Zhixin; Wang, Hongbin; Jin, Peng; Liu, Xiaoguang; Permaul, Kugenthiren; Singh, Suren; Wang, Zhengxiang

    2018-03-28

    Owing to its high protein secretion capacity, simple nutritional requirements, and GRAS (generally regarded as safe) status, Bacillus licheniformis is widely used as a host for the industrial production of enzymes, antibiotics, and peptides. However, as compared with its close relative Bacillus subtilis , little is known about the physiology and stress responses of B. licheniformis . To explore its temperature-stress metabolome, B. licheniformis strains ATCC 14580 and B186, with respective optimal growth temperatures of 42°C and 50°C, were cultured at 42°C, 50°C, and 60°C and their corresponding metabolic profiles were determined by gas chromatography/mass spectrometry and multivariate statistical analyses. It was found that with increased growth temperatures, the two B. licheniformis strains displayed elevated cellular levels of proline, glutamate, lysine, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid, and decreased levels of glutamine and octadecenoic acid. Regulation of amino acid and fatty acid metabolism is likely to be associated with the evolution of protective biochemical mechanisms of B. licheniformis . Our results will help to optimize the industrial use of B. licheniformis and other important Bacillus species.

  2. Diversity of burial rates in convergent settings decreased as Earth aged.

    Science.gov (United States)

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-05-24

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth's geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma(-1)) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision.

  3. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  4. Distributions of temperature and stress fields on penetration assembly during multi-pass welding

    International Nuclear Information System (INIS)

    Li Hong; Li Li

    2010-01-01

    Welding is a fundamental manufacturing technique used to join metal components. They cause errors during the assembly of the structure and reduce the strength of the structure. Based on an elastic-plastic-model, a three-dimensional finite element numerical simulation of a stainless steel penetration assembly during multi-pass welding with girth welds is carried out in this paper. And then the transient temperature field and the real-time dynamic stresses field of the structure are obtained. The heat source is modeled as a moving heat flux along girth welds following a double ellipsoid distribution. The 'birth and death' element method is applied to simulate the gradual growth of welding pass metal. The way of predicting the residual stresses in this paper can prepare an error-minimizing guide at design stage and can be used in accuracy management.

  5. Safety analysis of the Chernobyl accident origin decontamination waste burials in Belarus

    International Nuclear Information System (INIS)

    Skurat, V.V.; Shiryaeva, N.M.; Myshkina, N.K.; Gvozdev, A.A.; Serebryanyj, G.Z.; Golikova, N.B.

    2002-01-01

    Potential dangerous of the decontamination waste burials was estimated by means of the generalized multicompartmental model. Characteristics of 24 the most large and unfavorable decontamination waste burials are shown and an estimate of their safety is given. The burial effect zones were determined (100-300 m). A reliability of the forecasting estimate of potential dangerous radioactive contamination of ground waters near the burials was checked on example of the Dudichi decontamination waste burial

  6. Effect of temperature on oxidative stress induced by lead in the leaves of Plantago major L.

    Science.gov (United States)

    Balakhnina, Tamara I.; Borkowska, Aneta; Nosalewicz, Magdalena; Nosalewicz, Artur; Włodarczyk, Teresa M.; Kosobryukhov, Anatoly A.; Fomina, Irina R.

    2016-07-01

    Fluctuation of the summer day-time temperatures in the mid-latitudes in a range from 16 to 30°C should not have irreversible negative effects on plants, but may influence metabolic processes including the oxidative stress. To test the effect of moderately high temperature on oxidative stress induced by lead in the leaves of Plantago major L.; the plants were incubated in a water solution of 0, 150, 450, and 900 μM Pb (NO3)2 at 20 and 28°C. Plant reactions were evaluated by the content of thiobarbituric acid reactive substances and ascorbate peroxidase and glutathione reductase activities in leaves after 2, 24, 48, and 72 h. The Pb concentration in the leaves rose with the increase in the Pb content and was higher at 20°C. The increase in stomatal resistance caused by Pb was higher at 28°C. The contents of TBARS increased after 2 h of plant exposure to Pb and the increase was the highest at 900 μM Pb, 28°C. The AsP activity increased up to 50% after 24 h of Pb-treatment at 28°C; the highest increase in glutathione reductase activity was observed after 72 h at 20°C. Thus, the moderately high temperature 28°C compared with optimal 20°C caused a decrease in Pb accumulation in Plantago leaves but amplified the negative effects of lead, especially in the beginning of stress development.

  7. Tolerance of wheat and lettuce plants grown on human mineralized waste to high temperature stress

    Science.gov (United States)

    Ushakova, Sofya A.; Tikhomirov, Alexander A.; Shikhov, Valentin N.; Gros, Jean-Bernard; Golovko, Tamara K.; Dal'ke, Igor V.; Zakhozhii, Ilya G.

    2013-06-01

    The main objective of a life support system for space missions is to supply a crew with food, water and oxygen, and to eliminate their wastes. The ultimate goal is to achieve the highest degree of closure of the system using controlled processes offering a high level of reliability and flexibility. Enhancement of closure of a biological life support system (BLSS) that includes plants relies on increased regeneration of plant waste, and utilization of solid and liquid human wastes. Clearly, the robustness of a BLSS subjected to stress will be substantially determined by the robustness of the plant components of the phototrophic unit. The aim of the present work was to estimate the heat resistance of two plants (wheat and lettuce) grown on human wastes. Human exometabolites mineralized by hydrogen peroxide in an electromagnetic field were used to make a nutrient solution for the plants. We looked for a possible increase in the heat tolerance of the wheat plants using changes in photosynthetically active radiation (PAR) intensity during heat stress. At age 15 days, plants were subjected to a rise in air temperature (from 23 ± 1 °C to 44 ± 1 °С) under different PAR intensities for 4 h. The status of the photosynthetic apparatus of the plants was assessed by external СО2 gas exchange and fluorescence measurements. The increased irradiance of the plants during the high temperature period demonstrated its protective action for both the photosynthetic apparatus of the leaves and subsequent plant growth and development. The productivity of the plants subjected to temperature changes at 250 W m-2 of PAR did not differ from that of controls, whereas the productivity of the plants subjected to the same heat stress but in darkness was halved.

  8. Effect of Stress and Temperature on the Optical Properties of Silicon Nitride Membranes at 1,550 nm

    OpenAIRE

    Mark Fletcher; Simon Tait; Jessica Steinlechner; Jessica Steinlechner; Iain W. Martin; Angus S. Bell; James Hough; Sheila Rowan; Roman Schnabel

    2018-01-01

    Future gravitational-wave detectors operated at cryogenic temperatures are expected to be limited by thermal noise of the highly reflective mirror coatings. Silicon nitride is an interesting material for such coatings as it shows very low mechanical loss, a property related to low thermal noise, which is known to further decrease under stress. Low optical absorption is also required to maintain the low mirror temperature. Here, we investigate the effect of stress on the optical properties at ...

  9. Influence of temperature on the corticosterone stress-response: an experiment in the Children's python (Antaresia childreni).

    Science.gov (United States)

    Dupoué, Andréaz; Brischoux, François; Lourdais, Olivier; Angelier, Frédéric

    2013-11-01

    To cope with environmental challenges, organisms have to adjust their behaviours and their physiology to the environmental conditions they face (i.e. allostasis). In vertebrates, such adjustments are often mediated through the secretion of glucocorticoids (GCs) that are well-known to activate and/or inhibit specific physiological and behavioural traits. In ectothermic species, most processes are temperature-dependent and according to previous studies, low external temperatures should be associated with low GC concentrations (both baseline and stress-induced concentrations). In this study, we experimentally tested this hypothesis by investigating the short term influence of temperature on the GC stress response in a squamate reptile, the Children's python (Antaresia childreni). Snakes were maintained in contrasting conditions (warm and cold groups), and their corticosterone (CORT) stress response was measured (baseline and stress-induced CORT concentrations), within 48h of treatment. Contrary to our prediction, baseline and stress-induced CORT concentrations were higher in the cold versus the warm treatment. In addition, we found a strong negative relationship between CORT concentrations (baseline and stress-induced) and temperature within the cold treatment. Although it remains unclear how cold temperatures can mechanistically result in increased CORT concentrations, we suggest that, at suboptimal temperature, high CORT concentrations may help the organism to maintain an alert state. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Creep-Fatigue Life Design with Various Stress and Temperature Conditions on the Basis of Lethargy Coefficient

    International Nuclear Information System (INIS)

    Park, Jung Eun; Yang, Sung Mo; Han, Jae Hee; Yu, Hyo Sun

    2011-01-01

    High temperature and stress are encounted in power plants and vehicle engines. Therefore, determination of the creep-fatigue life of a material is necessary prior to fabricating equipment. In this study, life design was determined on the basis of the lethargy coefficient for different temperatures, stress and rupture times. SP-Creep test data was compared with computed data. The SP-Creep test was performed to obtain the rupture time for X20CrMoV121 steel. The integration life equation was considered for three cases with various load, temperature and load-temperature. First, the lethargy coefficient was calculated by using the obtained rupture stress and the rupture time that were determined by carrying out the SP-Creep test. Next, life was predicted on the basis of the temperature condition. Finally, it was observed that life decreases considerably due to the coupling effect that results when fatigue and creep occur simultaneously

  11. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    International Nuclear Information System (INIS)

    Seifert, H.P.

    2002-02-01

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  12. Stress Corrosion Cracking of Zircaloy-4 in Halide Solutions: Effect of Temperature

    Directory of Open Access Journals (Sweden)

    Farina S.B.

    2002-01-01

    Full Text Available Zircaloy-4 was found to be susceptible to stress corrosion cracking in 1 M NaCl, 1 M KBr and 1 M KI aqueous solutions at potentials above the pitting potential. In all the solutions tested crack propagation was initially intergranular and then changed to transgranular. The effect of strain rate and temperature on the SCC propagation was investigated. An increase in the strain rate was found to lead to an increase in the crack propagation rate. The crack propagation rate increases in the three solutions tested as the temperatures increases between 20 and 90 °C. The Surface-Mobility SCC mechanism accounts for the observation made in the present work, and the activation energy predicted in iodide solutions is similar to that found in the literature.

  13. Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis.

    Science.gov (United States)

    Delatorre, Jose; Pinto, Manuel; Cardemil, Liliana

    2008-08-21

    The main aim of this research was to compare the photosynthetic responses of two species of Prosopis, Prosopis chilensis (algarrobo) and Prosopis tamarugo (tamarugo) subjected to heat and water stress, to determine how heat shock or water deficit, either individually or combined, affect the photosynthesis of these two species. The photosynthetic rates expressed as a function of photon flow density (PFD) were determined by the O(2) liberated, in seedlings of tamarugo and algarrobo subjected to two water potentials: -0.3 MPa and -2.5 MPa and to three temperatures: 25 degrees C, 35 degrees C and 40 degrees C. Light response curves were constructed to obtain light compensation and light saturation points, maximum photosynthetic rates, quantum yields and dark respiration rates. The photochemical efficiency as the F(v)/F(m) ratio and the amount of RUBISCO were also determined under heat shock, water deficit, and under the combined action of both stress. Photosynthetic rates at a light intensity higher than 500 micromole photons m(-2)s(-1) were not significantly different (P>0.05) between species when measured at 25 degrees C under the same water potential. The maximum photosynthetic rates decreased with temperature in both species and with water deficit in algarrobo. At 40 degrees C and -2.5 MPa, the photosynthetic rate of algarrobo fell to 72% of that of tamarugo. The quantum yield decreased in algarrobo with temperature and water deficit and it was reduced by 50% when the conditions were 40 degrees C and -2.5 MPa. Dark respiration increased by 62% respect to the control at 40 degrees C in tamarugo while remained unchanged in algarrobo. The photochemical efficiency decreased with both, high temperature and water deficit, without differences between species. RUBISCO content increased in algarrobo 35 degrees C. Water deficit reduced the amount of RUBISCO in both species. The results of this work support the conclusion that in both Prosopis species, the interaction between

  14. Stability of machining induced residual stresses in Inconel 718 under quasi-static loading at room temperature

    International Nuclear Information System (INIS)

    Madariaga, A.; Esnaola, J.A.; Arrazola, P.J.; Ruiz-Hervias, J.; Muñoz, P.; Ostolaza, K.

    2015-01-01

    Tensile residual stresses are very often generated on the surface when machining nickel alloys. In order to determine their influence on the final mechanical behaviour of the component residual stress stability should be considered. In the present work the evolution of surface residual stresses induced by machining in Inconel 718 under static loading at room temperature was studied experimentally and numerically. An Inconel 718 disc was face turned employing industrial working conditions and specimens for tensile tests were extracted from the disc. Surface residual stresses were measured by X-ray diffraction for initial state and after applying different loads over the material's yield stress. Then, a finite element model based on the surface–core approach was fitted to experimental results and the study was extended to analyse the influence of load level, degree of work-hardening and initial surface conditions. For the studied case, initial tensile surface residual stress (776 MPa) became even more tensile when applying loads higher than the material yield stress, but a shift was observed at the highest applied load (1350 MPa) and initial residual stress was relaxed about 170 MPa. This particular behaviour is associated to the modified stress–strain properties of the machined affected surface layer which was strongly work-hardened. Moreover, if the work-hardened properties are not considered in the finite element model results differ substantially from experiments. Surface residual stress stability also depends on the initial surface residual stress, but the degree of work-hardening induced by the machining process must be considered as well. If the difference between the yield stress of the surface and the yield stress of the core is lower than the initial surface residual stress, the surface begins yielding first and consequently the surface residual stress is decreased. In contrast, if the difference between the yield stress of the surface and the

  15. Sensitivity to high temperature and water stress in recalcitrant Baccaurea ramiflora seeds.

    Science.gov (United States)

    Wen, Bin; Liu, Minghang; Tan, Yunhong; Liu, Qiang

    2016-07-01

    Southeast Asia experiences one of the highest rates of deforestation in the tropics due to agricultural expansion, logging, habitat fragmentation and urbanization. As tropical rainforests harbour abundant recalcitrant-seeded species, it is important to understand how recalcitrant seeds respond to deforestation and fragmentation. Baccaurea ramiflora is a recalcitrant-seeded species, widely distributed in Southeast Asian tropical rainforest. In this study, B. ramiflora seeds were sown in three plots, one in a nature reserve and two in disturbed holy hill forests, to investigate seed germination and seedling establishment in the field, while laboratory experiments were conducted to investigate the effects of high temperature and water stress on germination. It was found that seed germination and seedling establishment in B. ramiflora were clearly reduced in holy hills compared to the nature reserve, although the seeds were only moderately to minimally recalcitrant. This was potentially caused by increased temperature and decreased moisture in holy hills, for laboratory experiments showed that seed germination was greatly inhibited by temperatures ≥35 °C or water potentials ≤-0.5 MPa, and depressed by heat treatment at 40 °C when the continuous heating period lasted for 240 h or daily periodic heating exceeded 10 h. Unlike orthodox seeds, which can endure much higher temperatures in the air-dried state than in the imbibed state, both blotted and immersed B. ramiflora seeds lost viability within a narrow temperature range between 50 and 60 °C. As recalcitrant seeds can be neither air-dried nor heated, species producing recalcitrant seeds will suffer more than those producing orthodox seeds in germination and seedling establishment from increased temperature and decreased moisture in fragmented rainforests, which results in sensitivity of recalcitrant-seeded species to rainforest fragmentation.

  16. Stress corrosion cracking behaviour of Alloy 600 in high temperature water

    International Nuclear Information System (INIS)

    Webb, G.L.; Burke, M.G.

    1995-01-01

    The stress corrosion cracking (SCC) susceptibility of Alloy 600 in deaerated water at 360 deg. C, as measured with statistically-loaded U-bend specimens, is dependent upon microstructure and whether the material was cold-worked and annealed (CWA) or hot-worked and annealed (HWA). All cracking was intergranular, and materials lacking grain boundary carbides were most susceptible to SCC initiation. CWA tubing materials are more susceptible to SCC initiation than HWA ring-rolled forging materials with similar microstructures, as determined by light optical metallography (LOM). In CWA tubing materials one crack dominated and grew to a large size that was observable by visual inspection. HWA materials with a low hot-working finishing temperature (below 925 deg. C) and final anneals at temperatures ranging from 1010 deg. C to 1065 deg. C developed both large cracks, similar to those found in CWA materials, and also small intergranular microcracks, which are detectable only by destructive metallographic examination. HWA materials with a high hot-working finishing temperature (above 980 deg. C) and high-temperature final anneal (above 1040 deg. C), with grain boundaries that are fully decorated, developed only microcracks, which were observed in all specimens examined. These materials developed no large, visually detectable cracks, even after more than 300 weeks exposure. A low-temperature thermal treatment (610 deg. C for 7h), which reduced or eliminates SCC in Alloy 600, did not eliminate microcrack formation in the high temperature processed HWA materials. Detailed microstructural characterization using conventional metallographic and analytical electron microscopy (AEM) techniques was performed on selected materials to identify the factors responsible for the observed differences in cracking behaviour. 11 refs, 12 figs, 3 tabs

  17. Stress Concentration in the Bulk Cr2O3: Effects of Temperature and Point Defects

    Directory of Open Access Journals (Sweden)

    Mazharul M. Islam

    2017-01-01

    Full Text Available Modeling the growth and failure of passive oxide films formed on stainless steels is of general interest for the use of stainless steel as structural material and of special interest in the context of life time extension of light water reactors in nuclear power plants. Using the DFT+U approach, a theoretical investigation on the resistance to failure of the chromium-rich inner oxide layer formed at the surface of chromium-containing austenitic alloys (stainless steel and nickel based alloys has been performed. The investigations were done for periodic bulk models. The data at the atomic scale were extrapolated by using the Universal Binding Energy Relationships (UBERs model in order to estimate the mechanical behavior of a 10 μm thick oxide scale. The calculated stress values are in good agreement with experiments. Tensile stress for the bulk chromia was observed. The effects of temperature and structural defects on cracking were investigated. The possibility of cracking intensifies at high temperature compared to 0 K investigations. Higher susceptibility to cracking was observed in presence of defects compared to nondefective oxide, in agreement with experimental observation.

  18. S-methylmethionine reduces cell membrane damage in higher plants exposed to low-temperature stress.

    Science.gov (United States)

    Rácz, Ilona; Páldi, Emil; Szalai, Gabriella; Janda, Tibor; Pál, Magdolna; Lásztity, Demeter

    2008-09-29

    S-methylmethionine (SMM), an important intermediate compound in the sulphur metabolism, can be found in various quantities in majority of plants. The experiments were designed to determine the extent to which SMM is able to preserve cell membrane integrity or reduce the degree of membrane damage in the course of low-temperature stress. By measuring electrolyte leakage (EL), it was proved that SMM treatment reduced cell membrane damage, and thus EL, during low-temperature stress in both the leaves and roots of peas, maize, soy beans and eight winter wheat varieties with different levels of frost resistance. Investigations on the interaction between SMM and polyamine biosynthesis revealed that SMM increased the quantities of agmatine (Agm) and putrescine (Put) as well as that of spermidine (Spd), while it had no effect on the quantity of spermine (Spn). Using a specific inhibitor, methylglyoxal-bis-guanyl hydrazone (MGBG), it was proved that the polyamine metabolic pathway starting from methionine played no role in the synthesis of Spd or Spn, so there must be an alternative pathway for the synthesis of SMM-induced polyamines.

  19. Comparative transcriptome analysis of sweet corn seedlings under low-temperature stress

    Directory of Open Access Journals (Sweden)

    Jihua Mao

    2017-10-01

    Full Text Available Stress induced by low temperature, which represents a widespread environmental factor, strongly affects maize growth and yield. However, the physiological characteristics and molecular regulatory mechanisms of maize seedlings in response to cold remain poorly understood. In this study, using RNA-seq, we investigated the transcriptome profiles of two sweet corn inbred lines, “Richao” (RC and C5, under cold stress. A total of 357 and 455 differentially expressed genes (DEGs were identified in the RC and C5 lines, respectively, 94 DEGs were detected as common DEGs related to cold response in both genotypes, and a total of 589 DEGs were detected as cold tolerance-associated genes. By combining protein function clustering analysis and significantly enriched Gene Ontology (GO terms analysis, we suggest that transcription factors may play a dominating role in the cold stress response and tolerance of sweet corn. Furthermore, 74 differentially expressed transcription factors were identified, of those many genes involved in the metabolism and regulation of hormones. These results expand our understanding of the complex mechanisms involved in chilling tolerance in maize, and provide a set of candidate genes for further genetic analyses.

  20. Stress relaxation in 'aged high-purity aluminium at room temperature

    International Nuclear Information System (INIS)

    Butt, M.Z.; Haq, I.U.

    1993-01-01

    Stress relaxation in 99.996% Al polycrystals of average grain diameter 0.30, 0.42 and 0.51 mm, annealed at 500 deg. C and 'aged' for six months at room temperature, have been studied as a function of initial stress level from which relaxation at constant strain was allowed to start. The results obtained were compared with those for 'un-aged' Al specimens of the same purity and grain size. The intrinsic height of the thermally activable energy barrier (1.6 eV) evaluated for 'aged' Al is comparable with that (1.9 eV) for 'un-aged' Al, and is of the order of magnitude for recovery processes. In 'aged' specimens, the relaxation rate at a given stress level is larger and associated activation volume is smaller than that in 'un-aged' specimens. This is probably due to the diffusion of vacancies and/or residual impurity atoms to the cores to edge dislocations in 'aged' specimens; the length of dislocation segment involved in unit activation process therefore gets shortened compared with that in 'un-aged' specimens. (author)

  1. Stress corrosion cracking behavior of weldments of ferritic stainless steels in high temperature pure water

    International Nuclear Information System (INIS)

    Fujiwara, Kazuo; Tomari, Haruo; Shimogori, Kazutoshi

    1985-01-01

    Considering the application of a ferritic stainless steel as heat exchanger tubing for a moisture separator reheater of light water reactors, stress corrosion cracking behavior at the weldment of commercial ferritic stainless steels in high temperature pure water was studied. Double U-bend method was used for the study and the relationship with microstructure was discussed. Welded joint of Type 439SS containing 0.021% C, 0.025% N and 0.27% Ti with In-82 type filler metal was susceptible to intergranular stress corrosion cracking if a tight crevice was provided by inserting a teflon sheet between the inner and outer specimens of double U-bend. This was attributable to the formation of chromium depleted zone due to the precipitation of chromium carbides/nitrides along ferrite grain boundaries. On the other hand welded joint of Type 444SS with 0.007% C, 0.010% N and 0.26% Nb was immune to stress corrosion cracking, and this might be attributed to the higher ratio of Nb/(C+N) content. (author)

  2. 28-homobrassinolide Protects Photosynthetic Machinery in Indian mustard Under High Temperature Stress

    Directory of Open Access Journals (Sweden)

    Qazi Fariduddin

    2014-03-01

    Full Text Available High temperature is a serious threat to crop production. Brassinosteroids (BRs, a group of plant steroidal hormones, can reduce effects of abiotic stresses. The present study was aimed to study the potency of brassinosteroids on high temperature induced changes in Indian mustard (Brassica juncea L. for effects on growth, chlorophyll, photosynthesis, photosystem II, antioxidant system and proline. Surface sterilized seeds of Indian mustard were sown in pots, grown for 21 days and treated with double distilled water or 0.01 µM of 28-homobrassinolide. Treated plants, after 24 h, were exposed to 30°C or 40°C for 48 h. One set of plants were kept at ambient temperature, 25°C, as the control. Plants were harvested at 30 days stage of growth to assess the various parameters. Plants exposed to 40°C had a decline in growth, leaf water potential, chlorophyll, photosynthetic rate, and activities of carbonic anhydrase (E.C.4.2.1.1 and nitrate reductase (E.C.1.6.1.1. The 28-homobrassinolide alone improved growth and photosynthesis responses along with various enzymes activities. Treatment of plants with HBL prior to exposure to 40°C, partially reduced damage and completely controlled damage when exposure was to 30°C. Levels of the antioxidative enzymes catalase (E.C.1.11.1.6, peroxidase (E.C.1.11.1.7, and superoxide dismutase (E.C.1.15.1.1, and the level of proline increased in response to 30 or 40°C and were further enhanced in the presence of 28-homobrassinolide. Plants grown under high temperature had increased levels of H2O2; application of HBL before temperature treatment decreased H2O2 content compared to the control. Elevated levels of antioxidative enzymes and proline might be responsible for conferring tolerance to high temperature stress in Indian mustard and overcome the loss of productivity of the crop.

  3. Analysis of expressed sequence tags from Musa acuminata ssp. burmannicoides, var. Calcutta 4 (AA) leaves submitted to temperature stresses

    NARCIS (Netherlands)

    Santos, C.R.; Martins, N.F.; Horberg, H.M.; Almeida, E.R.P.; Coelho, M.C.F.; Togawa, R.; Silva, F.R.; Caetano, A.R.; Miller, R.N.G.; Souza, M.T.

    2005-01-01

    In order to discover genes expressed in leaves of Musa acuminata ssp. burmannicoides var. Calcutta 4 (AA), from plants submitted to temperature stress, we produced and characterized two full-length enriched cDNA libraries. Total RNA from plants subjected to temperatures ranging from 5°C to 25°C and

  4. Measurement and analysis of temperature, strain and stress of foundation mat concrete in nuclear and thermal power stations

    International Nuclear Information System (INIS)

    Haraguchi, Akira; Yamakawa, Hidetsugu; Abe, Hirotoshi

    1981-01-01

    The problems of the thermal stress in concrete structures are roughly divided into the initial stress due to setting heat and the stress due to external temperature after hardening. The initial stress exists in every concrete structure, and it is usually neglected in beams and columns, but it must be taken into account in case of the foundation mat structures in nuclear power stations, for example. In this paper, (1) the results of measurement of temperature, strain and stress in each lift at the time of and after placing concrete in the foundation mat of a nuclear power station and the comparison of them with the results of analysis, (2) the results of measurement of the temperature and stress in a foundation mat, which was carried out to rationalize the design method for the raft type foundation mats in thermal power stations, and (3) the results of examination on the analysis model, external force conditions and boundary conditions used for the design are reported. The analysis method for temperature and thermal stress by finite element method, developed by the Central Research Institute of Electric Power Industry, can take the changes in the heat of hydration in placed concrete, the creep phenomenon of concrete and the restraint at construction joints in consideration. It is necessary to collect the data on the measurement of mat concrete and to develop the accurate analysis method. (Kako, I.)

  5. Stresses evolution at high temperature (200°C on the interface of thin films in magnetic components

    Directory of Open Access Journals (Sweden)

    Doumit Nicole

    2014-07-01

    Full Text Available In the field of electronics, the increase of operating temperatures is a major industrial and scientific challenge because it allows reducing mass and volume of components especially in the aeronautic domain. So minimizing our components reduce masses and the use of cooling systems. For that, the behaviours and interface stresses of our components (in particular magnetic inductors and transformers that are constituted of one magnetic layer (YIG or an alumina substrate (Al2O3 representing the substrate and a thin copper film are studied at high temperature (200°C. COMSOL Multiphysics is used to simulate our work and to validate our measurements results. In this paper, we will present stresses results according to the geometrical copper parameters necessary for the component fabrication. Results show that stresses increase with temperature and copper’s thickness while remaining always lower than 200MPa which is the rupture stress value.

  6. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    International Nuclear Information System (INIS)

    Speidel, M.O.; Magdowski, R.

    1995-01-01

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  7. High temperature and stress corrosion cracking of 310S austenitic stainless steel in wet chloride corrosive environment

    Directory of Open Access Journals (Sweden)

    T. Pornpibunsompop

    2018-01-01

    Full Text Available High temperature corrosion and stress corrosion cracking of 310S austenitic stainless steel in wet chloride environment at a high temperature was investigated. The result showed that high temperature corrosion products mostly consisted of ferrous oxides and chromium oxides. Chloride ions attacked a chromium passive film and strongly reacted with iron and chromium. As a result of metal chlorides being volatized, tunnel of pores inside corrosion layer existed. Intergranular stress corrosion cracking was observed. The oxide originated on surface could act as a crack initiator and a crack propagation would progress along grain boundaries and particularly along tunnel of pores.

  8. Alternative oxidase pathway optimizes photosynthesis during osmotic and temperature stress by regulating cellular ROS, malate valve and antioxidative systems

    Directory of Open Access Journals (Sweden)

    DINAKAR eCHALLABATHULA

    2016-02-01

    Full Text Available The present study reveals the importance of alternative oxidase (AOX pathway in optimizing photosynthesis under osmotic and temperature stress conditions in the mesophyll protoplasts of Pisum sativum. The responses of photosynthesis and respiration were monitored at saturating light intensity of 1000 µmoles m-2 s-1 at 25 oC under a range of sorbitol concentrations from 0.4 M to 1.0M to induce hyper-osmotic stress and by varying the temperature of the thermo-jacketed pre-incubation chamber from 25 oC to 10 oC to impose sub-optimal temperature stress. Compared to controls (0.4 M sorbitol and 25 OC, the mesophyll protoplasts showed remarkable decrease in NaHCO3-dependent O2 evolution (indicator of photosynthetic carbon assimilation, under both hyper-osmotic (1.0 M sorbitol and sub-optimal temperature stress conditions (10 OC, while the decrease in rates of respiratory O2 uptake were marginal. The capacity of AOX pathway increased significantly in parallel to increase in intracellular pyruvate and reactive oxygen species (ROS levels under both hyper-osmotic stress and sub-optimal temperature stress under the background of saturating light. The ratio of redox couple (Malate/OAA related to malate valve increased in contrast to the ratio of redox couple (GSH/GSSG related to antioxidative system during hyper-osmotic stress. Nevertheless, the ratio of GSH/GSSG decreased in the presence of sub-optimal temperature, while the ratio of Malate/OAA showed no visible changes. Also, the redox ratios of pyridine nucleotides increased under hyper-osmotic (NADH/NAD and sub-optimal temperature (NADPH/NADP stresses, respectively. However, upon restriction of AOX pathway by using salicylhydroxamic acid (SHAM, the observed changes in NaHCO3 dependent O2 evolution, cellular ROS, redox ratios of Malate/OAA, NAD(PH/NAD(P and GSH/GSSG were further aggravated under stress conditions with concomitant modulations in NADP-MDH and antioxidant enzymes. Taken together, the

  9. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    Science.gov (United States)

    Chen, Jun; Shen, Jing

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed quickly. Raising the temperature to 37°C resulted in severe growth inhibition and only slow removal of dissolved oxygen. Under these conditions, an abnormally low intracellular ratio of [ATP] to [ADP] (1.4) was found (normally around 5), which indicates that the cells are energy limited. By adding riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C. These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller. The drop was accompanied by a decrease in NADH oxidase and pyruvate dehydrogenase activities, both of which depend on FAD as a cofactor. By overexpressing the riboflavin transporter, it was possible to improve FAD biosynthesis, which resulted in increased NADH oxidase and pyruvate dehydrogenase activities and improved fitness at high temperatures in the presence of oxygen. PMID:23913422

  10. Transcriptional profile of breast muscle in heat stressed layers is similar to that of broiler chickens at control temperature.

    Science.gov (United States)

    Zahoor, Imran; de Koning, Dirk-Jan; Hocking, Paul M

    2017-09-20

    In recent years, the commercial importance of changes in muscle function of broiler chickens and of the corresponding effects on meat quality has increased. Furthermore, broilers are more sensitive to heat stress during transport and at high ambient temperatures than smaller egg-laying chickens. We hypothesised that heat stress would amplify muscle damage and expression of genes that are involved in such changes and, thus, lead to the identification of pathways and networks associated with broiler muscle and meat quality traits. Broiler and layer chickens were exposed to control or high ambient temperatures to characterise differences in gene expression between the two genotypes and the two environments. Whole-genome expression studies in breast muscles of broiler and layer chickens were conducted before and after heat stress; 2213 differentially-expressed genes were detected based on a significant (P heat-stressed layers. Expression of these genes was further increased in heat-stressed broilers. Differences in gene expression between broiler and layer chickens under control and heat stress conditions suggest that damage of breast muscles in broilers at normal ambient temperatures is similar to that in heat-stressed layers and is amplified when broilers are exposed to heat stress. The patterns of gene expression of the two genotypes under heat stress were almost the polar opposite of each other, which is consistent with the conclusion that broiler chickens were not able to cope with heat stress by dissipating their body heat. The differentially expressed gene networks and pathways were consistent with the pathological changes that are observed in the breast muscle of heat-stressed broilers.

  11. Thermophysical and Mechanical Properties of Granite and Its Effects on Borehole Stability in High Temperature and Three-Dimensional Stress

    Science.gov (United States)

    Bao-lin, Liu; Hai-yan, Zhu; Chuan-liang, Yan; Zhi-jun, Li; Zhi-qiao, Wang

    2014-01-01

    When exploiting the deep resources, the surrounding rock readily undergoes the hole shrinkage, borehole collapse, and loss of circulation under high temperature and high pressure. A series of experiments were conducted to discuss the compressional wave velocity, triaxial strength, and permeability of granite cored from 3500 meters borehole under high temperature and three-dimensional stress. In light of the coupling of temperature, fluid, and stress, we get the thermo-fluid-solid model and governing equation. ANSYS-APDL was also used to stimulate the temperature influence on elastic modulus, Poisson ratio, uniaxial compressive strength, and permeability. In light of the results, we establish a temperature-fluid-stress model to illustrate the granite's stability. The compressional wave velocity and elastic modulus, decrease as the temperature rises, while poisson ratio and permeability of granite increase. The threshold pressure and temperature are 15 MPa and 200°C, respectively. The temperature affects the fracture pressure more than the collapse pressure, but both parameters rise with the increase of temperature. The coupling of thermo-fluid-solid, greatly impacting the borehole stability, proves to be a good method to analyze similar problems of other formations. PMID:24778592

  12. Calculation of Transient Temperature and Thermal Stresses at Calculus of Heat Transfer Coefficient Considering the Radiation

    Directory of Open Access Journals (Sweden)

    Gorbunov A.D.

    2016-04-01

    Full Text Available The problem of simplifications for solving problems of cooling / heating of bodies under the joint action of convection and radiation is considered. The mathematical formulation of the problem of non-stationary nonlinear heat, allowing along with convection, to take approximately into account the heat radiation. The solution of the problem for a thin body thermal model, based on the substitution method, linearizing the right boundary condition, as well as through the integral equation relationship between heat flow and surface-average and mass – average temperatures for the simple bodies in a regular stage of thermal conductivity. Two engineering methods were developed for calculating the temperature fields and axial thermal stresses during cooling (heating bodies of simple shape in the form of a plate, ball, and cylinder by convection and radiation in quasi-stationary stage. It is shown that neglecting heat transfer by radiation can lead to significant errors in calculation of the temperatures (up to 26%. The adequacy of the solutions has been tested at extreme cases, in the lack of heat transfer by radiation.

  13. Seed viability of Dimorphandra gardneriana subject to water stress in different temperatures

    Directory of Open Access Journals (Sweden)

    Marina Matias Ursulino

    Full Text Available ABSTRACT: The forest species Dimorphandra gardneriana Tul. is widely used for various pharmacological products, yet few basic studies have been undertaken to understand their ecological and physiological attributes under stress conditions. The goal of this research was to evaluate the seed germination and vigor when subjected to different osmotic potentials and temperatures. Water restriction was simulated with polyethylene glycol 6000 solution (PEG 6000 with osmotic potentials of 0; -0,2; -0,4; -0,6; -0,8, and -1,0MPa at temperatures of 20, 25, 30, and 35°C. The effect of the treatment was determined by the germination and vigor (germination speed index, length and phytomass of dry shoot and roots of the seeds, in an entirely random design with four repetitions. From-0, 4MPa it occurs a drastic reduction in germination and vigor of seeds although these factors were less affected at temperature of 25°C up to -0, 2MPa.

  14. Low temperature tensile properties and stress corrosion cracking resistance in the super duplex stainless steels weldments

    International Nuclear Information System (INIS)

    Lee, Jeung Woo; Sung, Jang Hyun; Lee, Sung Keun

    1998-01-01

    Low temperature tensile properties and SCC resistances of super duplex stainless steels and their weldments are investigated. Tensile strengths increase remarkably with decreasing test temperature, while elongations decrease steeply at -196 .deg. C after showing peak or constant value down to -100 .deg. C. Owing to the low tensile deformation of weld region, elongations of welded specimen decrease in comparison to those of unwelded specimen. The welded tensile specimen is fractured through weld region at -196 .deg. C due to the fact that the finely dispersed ferrite phase in the austenite matrix increases an opportunity to supply the crack propagation path through the brittle ferrite phase at low temperature. The stress corrosion cracking initiates preferentially at the surface ferrite phase of base metal region and propagates through ferrite phase. When the corrosion crack meets with the fibrously aligned austenite phase to the tensile direction, the ferrite phase around austenite continues to corrode. Eventually, fracture of the austenite phase begins without enduring the tensile load. The addition of Cu+W to the super duplex stainless steel deteriorates the SCC resistance in boiling MgCl 2 solution, possibly due to the increment of pits in the ferrite phase and reduction of N content in the austenite phase

  15. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

  16. Influence of Anchoring on Burial Depth of Submarine Pipelines.

    Science.gov (United States)

    Zhuang, Yuan; Li, Yang; Su, Wei

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed.

  17. The Semiotics of Pemature Burial: Feminism in a Postfeminist Age

    Directory of Open Access Journals (Sweden)

    Mary Hawkesworth

    2006-09-01

    Full Text Available In this article, I will explore how the death of feminism is represented in order to plumb the larger meanings embedded in proclamations of feminism’s symbolic death. I will begin by investigating two mechanisms by which feminism’s death has been produced to unearth the tacit values of feminism’s morticians. I will then consider competing accounts of the “signs of death” in order to explore how particular assumptions about the ontology of feminism are tied to specific forms of metaphorical death. Given the particular kind of distortion involved in the premature burial of a thriving global feminism, the final section of the article situates contemporary feminism’s death knell in the context of a gendered history of live burial practices. By excavating and interpreting such archaic practices, I will link the rhetorical burial of contemporary feminism to an ongoing effort to undermine feminist struggles for social justice.

  18. Thermally activated low temperature creep and primary water stress corrosion cracking of NiCrFe alloys

    International Nuclear Information System (INIS)

    Hall, M.M. Jr.

    1993-01-01

    A phenomenological SCC-CGR model is developed based on an apriori assumption that the SCC-CGR is controlled by low temperature creep (LTC). This mode of low temperature time dependent deformation occurs at stress levels above the athermal flow stress by a dislocation glide mechanism that is thermally activated and may be environmentally assisted. The SCC-CGR model equations developed contain thermal activation parameters descriptive of the dislocation creep mechanism. Thermal activation parameters are obtained by fitting the CGR model to SCC-CGR data obtained on Alloy 600 and Alloy X-750. These SCC-CGR activation parameters are compared to LTC activation parameters obtained from stress relaxation tests. When the high concentration of hydrogen at the tip of an SCC crack is considered, the SCC-CGR activation energies and rate sensitivities are shown to be quantitatively consistent with hydrogen reducing the activation energy and increasing the strain rate sensitivity in LTC stress relaxation tests. Stress dependence of SCC-CGR activation energy consistent with that found for the LTC activation energy. Comparisons between temperature dependence of the SCC-CGR stress sensitivity and LTC stress sensitivity provide a basis for speculation on effects of hydrogen and solute carbon on SCC crack growth rates

  19. Water stress index for alkaline fen habitat based on UAV and continuous tower measurements of canopy infrared temperature

    Science.gov (United States)

    Ciężkowski, Wojciech; Jóźwiak, Jacek; Chormański, Jarosław; Szporak-Wasilewska, Sylwia; Kleniewska, Małgorzata

    2017-04-01

    This study is focused on developing water stress index for alkaline fen, to evaluate water stress impact on habitat protected within Natura 2000 network: alkaline fens (habitat code:7230). It is calculated based on continuous measurements of air temperature, relative humidity and canopy temperature from meteorological tower and several UAV flights for canopy temperature registration. Measurements were taken during the growing season in 2016 in the Upper Biebrza Basin in north-east Poland. Firstly methodology of the crop water stress index (CWSI) determination was used to obtained non-water stress base line based on continuous measurements (NWSBtower). Parameters of NWSBtower were directly used to calculate spatial variability of CWSI for UAV thermal infrared (TIR) images. Then for each UAV flight day at least 3 acquisition were performed to define NWSBUAV. NWSBUAV was used to calculate canopy waters stress for whole image relative to the less stressed areas. The spatial distribution of developed index was verified using remotely sensed indices of vegetation health. Results showed that in analysed area covered by sedge-moss vegetation NWSB cannot be used directly. The proposed modification of CWSI allows identifying water stress in alkaline fen habitats and was called as Sedge-Moss Water Stress Index (SMWSI). The study shows possibility of usage remotely sensed canopy temperature data to detect areas exposed to the water stress on wetlands. This research has been carried out under the Biostrateg Programme of the Polish National Centre for Research and Development (NCBiR), project No.: DZP/BIOSTRATEG-II/390/2015: The innovative approach supporting monitoring of non-forest Natura 2000 habitats, using remote sensing methods (HabitARS).

  20. Identification and Expression Profile of CYPome in Perennial Ryegrass and Tall Fescue in Response to Temperature Stress

    Directory of Open Access Journals (Sweden)

    Xiang Tao

    2017-11-01

    Full Text Available Plant cytochrome P450s are involved in a wide range of biosynthetic reactions that generate various biomolecules, including a variety of defensive compounds. Perennial ryegrass (Lolium perenne and tall fescue (Festuca arundinacea are two major species of turf and forage grasses that usually experience low temperature below −10°C and high temperature over 38°C around the world. In this study, we re-analyzed transcriptome of perennial ryegrass and tall fescue treated with heat and cold stress. Thus, we can evaluate P450 composition in these species and confirm whether P450 genes response to temperature stress. We identified 277 and 319 P450 transcripts with open reading frames larger than 300 bp, respectively. These P450 transcripts were mainly classed in the CYP71, 51, 94, 89, 72, and 734 families. In perennial ryegrass and tall fescue, a total of 66 and 62 P450 transcripts were up-regulated, and 65 and 117 transcripts were down-regulated when subjected to heat stress, respectively. When exposed to cold stress, 60 and 73 transcripts were up-regulated, and 59 and 77 transcripts were down-regulated in perennial ryegrass and tall fescue. Among these differentially expressed transcripts, 64 and 87 of them showed expression level changes that followed the same trend, and these temperature-responsive genes primarily belong to the CYP71, 72 and 99 families. Besides, heat and cold stress altered phenylalanine and brassinosteroid involved P450 transcripts in perennial ryegrass and tall fescue. P450 transcripts involved in the metabolism of these compounds showed a strong response to heat and/or cold stress, indicating that they likely play important roles in temperature acclimation in these two species. The CYPome provide a genetic base for the future functional studies, as well as genetic studies that may improve stress tolerance for perennial ryegrass and tall fescue to extreme temperature.

  1. Effects of body temperature on post-anoxic oxidative stress from the perspective of postnatal physiological adaptive processes in rats.

    Science.gov (United States)

    Kletkiewicz, H; Rogalska, J; Nowakowska, A; Wozniak, A; Mila-Kierzenkowska, C; Caputa, M

    2016-04-01

    It is well known that decrease in body temperature provides protection to newborns subjected to anoxia/ischemia. We hypothesized that the normal body temperature of 33°C in neonatal rats (4°C below normal body temperature in adults) is in fact a preadaptation to protect CNS from anoxia and further reductions as well as elevations in temperature may be counterproductive. Our experiments aimed to examine the effect of changes in body temperature on oxidative stress development in newborn rats exposed to anoxia. Two-day-old Wistar rats were divided into 4 temperature groups: i. hypothermic at body temperature of 31°C, ii. maintaining physiological neonatal body temperature of 33°C, iii. forced to maintain hyperthermic temperature of 37°C, and i.v. forced to maintain hyperthermic temperature of 39°C. The temperature was controlled starting 15 minutes before and afterword during 10 minutes of anoxia as well as for 2 hours post-anoxia. Cerebral concentrations of lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CD) and the activities of antioxidant enzymes had been determined post mortem: immediately after anoxia was finished and 3, 7, and 14 days later. There were no post-anoxic changes in the concentration of MDA, CD and in antioxidant enzymes activity in newborn rats kept at their physiological body temperature of 33°C. In contrast, perinatal anoxia at body temperature elevated to 37°C or 39°C as well as under hypothermic conditions (31°C) intensified post-anoxic oxidative stress and depleted the antioxidant pool. Overall, these findings suggest that elevated body temperature (hyperthermia or fever), as well as exceeding cooling beyond the physiological level of body temperature of newborn rats, may extend perinatal anoxia-induced brain lesions. Our findings provide new insights into the role of body temperature in anoxic insult in vivo.

  2. Stress- and Magnetic Field-Induced Martensitic Transformation at Cryogenic Temperatures in Fe-Mn-Al-Ni Shape Memory Alloys

    Science.gov (United States)

    Xia, Ji; Xu, Xiao; Miyake, Atsushi; Kimura, Yuta; Omori, Toshihiro; Tokunaga, Masashi; Kainuma, Ryosuke

    2017-12-01

    Stress-induced and magnetic-field-induced martensitic transformation behaviors at low temperatures were investigated for Fe-Mn-Al-Ni alloys. The magnetic-field-induced reverse martensitic transformation was directly observed by in situ optical microscopy. Magnetization measurements under pulsed magnetic fields up to 50 T were carried out at temperatures between 4.2 and 125 K on a single-crystal sample; full magnetic-field-induced reverse martensitic transformation was confirmed at all tested temperatures. Compression tests from 10 to 100 K were conducted on a single-crystal sample; full shape recovery was obtained at all tested temperatures. It was found that the temperature dependence of both the critical stress and critical magnetic field is small and that the transformation hysteresis is less sensitive to temperature even at cryogenic temperatures. The temperature dependence of entropy change during martensitic transformation up to 100 K was then derived using the Clausius-Clapeyron relation with critical stresses and magnetic fields.

  3. Effect of thermal stabilization on the low-temperature stress-corrosion cracking of Inconel 600

    International Nuclear Information System (INIS)

    Bandy, R.; van Rooyen, D.

    1983-01-01

    The propensity to low-temperature stress-corrosion cracking (SCC) of thermally stabilized Inconel 600 in sulfur-bearing environments has been investigated using U-bends and slow-strain-rate testing. The results have been compared with those of sensitized Inconel 600. The potential dependence of crack-propagation rate has been established in a single test by using several U-bends held at different potentials, by choosing an appropriate electrical circuitry. The difference in SCC susceptibility of the sensitized and stabilized materials is discussed in terms of the grain-boundary chromium depletion and resulting intergranular attack in boiling ferric sulfate-sulfuric acid tests, and electrochemical potentiokinetic reactivation (EPR) tests. 10 figures

  4. Stress induced martensite transformation in Co–28Cr–6Mo alloy during room temperature deformation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, S., E-mail: song_cai@fwmetals.com [Fort Wayne Metals Research Products Corporation, 9609 Ardmore Avenue, Fort Wayne, IN 46809 (United States); Daymond, M.R. [Department of Mechanical and Materials Engineering, Queen' s University, Nicol Hall, 60 Union Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Ren, Y. [Advanced Photon Source, Argonne National Laboratory, 9700S. Cass Avenue, 433/D008, Argonne, IL 60439 (United States)

    2013-09-15

    The phase transformation and texture change of two Co–28Cr–6Mo alloys during room temperature deformation were studied by using the in-situ synchrotron X-ray diffraction. It is found that a slight difference in chemical compositions can significantly change the phase constitutions and the mechanical properties. For the material with less Ni, C and N (lower α-phase stability), increasing the grain size promotes the athermal martensite transformation during cooling. The kinetics of the Stress Induced Martensite (SIM) phase transformation may be more affected by the athermal martensite instead of the grain size of the α-phase. After deformation, similar textures are produced in samples regardless the differences in the initial structures such as the phase constitution and the grain size; while a relatively strong {111} texture and a weak {100} texture are produced in the α-phase, a {101"¯1} fiber texture is gradually developed in the ε-phase during uniaxial tension.

  5. Reflex sympathetic dystrophy and repetitive strain injury: temperature and microcirculatory changes following mild cold stress.

    Science.gov (United States)

    Cooke, E D; Steinberg, M D; Pearson, R M; Fleming, C E; Toms, S L; Elusade, J A

    1993-01-01

    Temperature and blood flow studies were performed in the upper limbs of six patients with reflex sympathetic dystrophy (RSD), nine patients with repetitive strain injury (RSI) and 12 control subjects using thermography, laser Doppler flowmetry, infrared photoplethysmography and venous occlusion strain gauge plethysmography. The contralateral responses of the symptomatic and asymptomatic limbs were examined after being subjected, separately, to mild cold stress (20 degrees C for 1 min). Altered thermoregulation and haemodynamics were evident in RSD. Though the pattern of response to contralateral cold challenge is similar to normal in RSI, vasodilatation and reduced vasomotion appears to be characteristic in this condition. Such changes may assist in distinguishing between RSD and RSI from other causes of chronic upper limb pain. PMID:8308805

  6. Estimated erosion rate at the SRP burial ground

    International Nuclear Information System (INIS)

    Horton, J.H.; Wilhite, E.L.

    1978-04-01

    The rate of soil erosion at the Savannah River Plant (SRP) burial ground can be calculated by means of the universal soil loss equation. Erosion rates estimated by the equation are more suitable for long-term prediction than those which could be measured with a reasonable effort in field studies. The predicted erosion rate at the SRP burial ground ranges from 0.0007 cm/year under stable forest cover to 0.38 cm/year if farmed with cultivated crops. These values correspond to 170,000 and 320 years, respectively, to expose waste buried 4 ft deep

  7. Changes in carbohydrate content in zucchini fruit (Cucurbita pepo L.) under low temperature stress.

    Science.gov (United States)

    Palma, Francisco; Carvajal, Fátima; Lluch, Carmen; Jamilena, Manuel; Garrido, Dolores

    2014-03-01

    The postharvest handling of zucchini fruit includes low-temperature storage, making cold stress unavoidable. We have investigated the changes of soluble carbohydrates under this stress and its relation with weight loss and chilling injury in zucchini fruit during postharvest storage at 4 °C and 20 °C for up to 14 days. Two varieties with different degrees of chilling tolerance were compared: Natura, the more tolerant variety, and Sinatra, the variety that suffered more severe chilling-injury symptoms and weight loss. In both varieties, total soluble carbohydrates, reducing soluble carbohydrates and polyols content was generally higher during storage at 4 °C than at 20 °C, thus these parameters are related to the physiological response of zucchini fruit to cold stress. However, the raffinose content increased in Natura and Sinatra fruits during storage at 4 °C and 20 °C, although at 20 °C the increase in raffinose was more remarkable than at 4 °C in both varieties, so that the role of raffinose could be more likely related to dehydration than to chilling susceptibility of zucchini fruit. Glucose, fructose, pinitol, and acid invertase activity registered opposite trends in both varieties against chilling, increasing in Natura and decreasing in Sinatra. The increase in acid invertase activity in Natura fruit during cold storage could contribute in part to the increase of these reducing sugars, whose metabolism could be involved in the adaptation to postharvest cold storage. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Analysis of stress intensity factor for a Griffith crack opened under constant pressure in a plate with temperature dependent properties

    International Nuclear Information System (INIS)

    Hata, Toshiaki

    1982-01-01

    Recently, the research on the thermal stress of structural materials has become important with the progress of nuclear reactor technology. In the case of large temperature gradient, the change of the physical properties of materials must be taken into account. The thermal stress analysis for the things with cracks taking the temperature dependence of properties into account has scarcely been carried out. In this report, the general method of solution of three-dimensional problems using perturbation method and the extension of thermo-elastic displacement potential method is shown for the case in which Young's modulus changes according to the exponential function of temperature. Moreover, using this method, the effect of the temperature dependence of properties on the stress intensity factor of the cracks subjected to internal pressure in a strip exposed to linear thermal flow was clarified. In the analysis, Young's modulus, the coefficient of linear thermal expansion and thermal conductivity were assumed to be dependent on temperature. The method of solution, the analysis of stress intensity factor considering the change of properties due to temperature, and the numerical calculation for a square plate with a crack are explained. (Kako, I.)

  9. Temperature as a potent driver of regional forest drought stress and tree mortality

    Science.gov (United States)

    Williams, A. Park; Allen, Craig D.; Macalady, Alison K.; Griffin, Daniel; Woodhouse, Connie A.; Meko, David M.; Swetnam, Thomas W.; Rauscher, Sara A.; Seager, Richard; Grissino-Mayer, Henri D.; Dean, Jeffrey S.; Cook, Edward R.; Gangodagamage, Chandana; Cai, Michael; McDowell, Nathan G.

    2012-01-01

    s the climate changes, drought may reduce tree productivity and survival across many forest ecosystems; however, the relative influence of specific climate parameters on forest decline is poorly understood. We derive a forest drought-stress index (FDSI) for the southwestern United States using a comprehensive tree-ring data set representing AD 1000-2007. The FDSI is approximately equally influenced by the warm-season vapour-pressure deficit (largely controlled by temperature) and cold-season precipitation, together explaining 82% of the FDSI variability. Correspondence between the FDSI and measures of forest productivity, mortality, bark-beetle outbreak and wildfire validate the FDSI as a holistic forest-vigour indicator. If the vapour-pressure deficit continues increasing as projected by climate models, the mean forest drought-stress by the 2050s will exceed that of the most severe droughts in the past 1,000 years. Collectively, the results foreshadow twenty-first-century changes in forest structures and compositions, with transition of forests in the southwestern United States, and perhaps water-limited forests globally, towards distributions unfamiliar to modern civilization.

  10. Saccharomyces cerevisiae KNU5377 Stress Response during High-Temperature Ethanol Fermentation

    Science.gov (United States)

    Kim, Il-Sup; Kim, Young-Saeng; Kim, Hyun; Jin, Ingnyol; Yoon, Ho-Sung

    2013-01-01

    Fuel ethanol production is far more costly to produce than fossil fuels. There are a number of approaches to cost-effective fuel ethanol production from biomass. We characterized stress response of thermotolerant Saccharomyces cerevisiae KNU5377 during glucose-based batch fermentation at high temperature (40°C). S. cerevisiae KNU5377 (KNU5377) transcription factors (Hsf1, Msn2/4, and Yap1), metabolic enzymes (hexokinase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, and alcohol dehydrogenase), antioxidant enzymes (thioredoxin 3, thioredoxin reductase, and porin), and molecular chaperones and its cofactors (Hsp104, Hsp82, Hsp60, Hsp42, Hsp30, Hsp26, Cpr1, Sti1, and Zpr1) are upregulated during fermentation, in comparison to S. cerevisiae S288C (S288C). Expression of glyceraldehyde-3-phosphate dehydrogenase increased significantly in KNU5377 cells. In addition, cellular hydroperoxide and protein oxidation, particularly lipid peroxidation of triosephosphate isomerase, was lower in KNU5377 than in S288C. Thus, KNU5377 activates various cell rescue proteins through transcription activators, improving tolerance and increasing alcohol yield by rapidly responding to fermentation stress through redox homeostasis and proteostasis. PMID:23512334

  11. Stress Corrosion Cracking of alloy 600 in high temperature water: a study of mechanisms

    International Nuclear Information System (INIS)

    Boursier, J.M.; Bouvier, O. de; Gras, J.M.; Noel, D.; Vaillant, F.; Rios, R.

    1992-12-01

    Investigations of the stress corrosion cracking behaviour of Alloy 600 tubing in high temperature water were performed in order to get a precise knowledge of the different stages of the cracking and their dependence on various parameters. The compatibility of the results with the main mechanisms to be considered was examined. Results showed three stages in the cracking: a true incubation time, a slow-rate propagation period followed by a rapid-propagation stage. Tests separating stress and strain rate contributions show that the strain rate is the main parameter which controls the crack propagation. The hydrogen overpressure was found to increase the crack growth rate up to 1-4 bar, but a strong decrease is observed from 4 to 20 bar. Analysis of the hydrogen ingress in the metal showed that it is neither correlated to the hydrogen overpressure nor to the severity of cracking; so cracking resulting from an hydrogen-model is unlikely. No detrimental effect of oxygen (4 bar) was noticed both in the mill-annealed and the sensitized conditions. Finally, none of the classical mechanisms, neither hydrogen-assisted cracking nor slip-step dissolution, can correctly describe the observed behaviour. Some fractographic examinations, and an influence of primary water on the creep rate of Alloy 600, lead to consider that other recent mechanisms, involving an interaction between dissolution and plasticity, have to be considered

  12. Recombination luminescence in irradiated silicon-effects of uniaxial stress and temperature variations.

    Science.gov (United States)

    Jones, C. E.; Compton, W. D.

    1971-01-01

    Demonstration that luminescence in irradiated silicon consists of a spectral group between 0.80 and 1.0 eV which seems to be independent of impurities, while a lower energy group between 0.60 and 0.80 eV is seen only in pulled crystals. The small halfwidth and temperature dependence of the sharp zero-phonon lines observed in these spectra indicate that the luminescence arises from a bound-to-bound transition. A model is proposed for the transition mechanism. Stress data taken on the 0.79-eV zero-phonon line in pulled crystals can be fit by either a tetragonal 100 (in brackets) defect symmetry or by conduction-band splitting effects. It is suggested that the 0.79-eV zero-phonon line and the 0.60- to 0.80-eV spectral group arise from the EPR G-15 center. Stress data on a zero-phonon line at 0.97 eV associated with the 0.80- to 1.0-eV spectral group can be explained by a trigonal 111 (in brackets) defect. The divacancy is tentatively suggested as responsible for this luminescence spectra.

  13. The effect of inertia, viscous damping, temperature and normal stress on chaotic behaviour of the rate and state friction model

    Science.gov (United States)

    Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

    2018-04-01

    A fundamental understanding of frictional sliding at rock surfaces is of practical importance for nucleation and propagation of earthquakes and rock slope stability. We investigate numerically the effect of different physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic behaviour of the two state variables rate and state friction (2sRSF) model. In general, a slight variation in any of inertia, viscous damping, temperature and effective normal stress reduces the chaotic behaviour of the sliding system. However, the present study has shown the appearance of chaos for the specific values of normal stress before it disappears again as the normal stress varies further. It is also observed that magnitude of system stiffness at which chaotic motion occurs, is less than the corresponding value of critical stiffness determined by using the linear stability analysis. These results explain the practical observation why chaotic nucleation of an earthquake is a rare phenomenon as reported in literature.

  14. The behavior of stress correlations and glass transition temperature in liquid aluminum at cooling and heating process

    Science.gov (United States)

    Kirova, E. M.; Pisarev, V. V.

    2018-01-01

    Molecular dynamics study of stress correlations and shear viscosity behavior of the rapidly cooled and re-heated liquid aluminum film is performed. The embedded atom method potential is used at the simulation. The stress correlation behavior is studied in the plane of the film and along the direction normal to the plane. The behavior of the kinematic viscosity and the stress correlations are compared for cooling and heating process. Using two methods we showed that the glass transition for the cooling process is higher than for the heating. The first method is based on the stress correlations in the plane of the film and the steep change of the kinematic viscosity. The second method is based on the transverse oscillations in the film. The glass transition temperature is estimated from the dependence of the oscillation damping on temperature. The increasing in the kinematic viscosity correlates with the decrease of transverse oscillations damping in the film.

  15. Effect of Stress and Temperature on the Optical Properties of Silicon Nitride Membranes at 1,550 nm

    Directory of Open Access Journals (Sweden)

    Mark Fletcher

    2018-01-01

    Full Text Available Future gravitational-wave detectors operated at cryogenic temperatures are expected to be limited by thermal noise of the highly reflective mirror coatings. Silicon nitride is an interesting material for such coatings as it shows very low mechanical loss, a property related to low thermal noise, which is known to further decrease under stress. Low optical absorption is also required to maintain the low mirror temperature. Here, we investigate the effect of stress on the optical properties at 1,550 nm of silicon nitride membranes attached to a silicon frame. Our approach includes the measurement of the thermal expansion coefficient and the thermal conductivity of the membranes. The membrane and frame temperatures are varied, and translated into a change in stress using finite element modeling. The resulting product of the optical absorption and thermo-optic coefficient (dn/dT is measured using photothermal common-path interferometry.

  16. The co-action of osmotic and high temperature stresses results in a growth improvement of Debaryomyces hansenii cells

    Czech Academy of Sciences Publication Activity Database

    Papoušková, Klára; Sychrová, Hana

    2007-01-01

    Roč. 118, č. 1 (2007), s. 1-7 ISSN 0168-1605 R&D Projects: GA ČR(CZ) GD204/03/H066; GA ČR(CZ) GA206/05/0035; GA MŠk(CZ) LC531; GA AV ČR(CZ) IAA5011407 Institutional research plan: CEZ:AV0Z50110509 Keywords : D. hansenii * osmotic stress * temperature stress Subject RIV: EE - Microbiology, Virology Impact factor: 2.581, year: 2007

  17. Influence of acute erythrocythemia on temperature regulation during exercise-heat stress

    International Nuclear Information System (INIS)

    Sawka, M.N.; Gonzalez, R.R.; Dennis, R.C.; Young, A.J.; Muza, S.R.; Martin, J.W.; Francesconi, R.P.; Pandolf, K.B.; Valeri, C.R.

    1986-01-01

    We studied the effects of acute erythrocythemia on temperature regulation responses during exercise in the heat. In a double blind study, 6 subjects (Ss) received a 700-ml solution of autologous red blood cells at a 60% Hct, and 3 Ss (control) received a 700-ml saline solution. All Ss attempted a Heat Stress Test (HST) two weeks prior to and 48-h post-transfusion during summer months. After 30 min of rest in a 20 0 C antechamber, the HST consisted of a 120-min exposure (two repeats of 15-min rest and 45-min treadmill walk) in a 35 0 C, 45% rh environment while euhydrated. Maximal oxygen uptake (VO 2 max) and red cell volume (RCV, 51 Cr) were measured approximately 24 h before each HST. For experimental Ss, an increase in RCV (11%, P 2 max (11%, P < 0.05) was found following transfusion, whereas, differences were not observed in the control Ss. During the HSTs for experimental Ss, metabolic rate as well as steady state rectal and esophageal temperatures were similar, but heat storage tended (P = 0.13) to be lower post-transfusion. Steady state local arm (R + C) was reduced (P < 0.05) with no change in total body sweating rate or local arm evaporative heat loss post-transfusion. For control Ss, thermoregulatory responses were generally not altered post-transfusion. Erythrocythemia may improve steady state sensible heat exchange by allowing a greater volume of blood to be directed to the cutaneous vasculature

  18. Stress Corrosion Behavior of Low-temperature Liquid-Nitrided 316 Austenitic Stainless Steel in a Sour Environment

    Science.gov (United States)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Yan, Jing; Duan, Lian; Gu, Tan; Xian, Guang; Sun, Lan; Wang, Danqi

    2018-01-01

    Low-temperature nitridation is a widely used surface heat treatment. Low-temperature liquid nitridation was applied to 316 austenitic stainless steel and an S-phase (expanded austenite) layer was achieved on the alloy surface. The effect of the S-phase layer on corrosion resistance and stress corrosion cracking was investigated in a sour environment. When a bending stress of 164 MPa (80 pct yield stress, YS) was applied, no macroscopic corrosion cracking and pits were observed on the nitrided samples and the S-phase layer stayed intact. Although no macroscopic corrosion cracking was observed on the non-nitrided samples under 205 MPa (100 pct YS), some pits were formed on the alloy surface. This could be attributed to the high stresses and hardness, and the excellent corrosion resistance of the S-phase layer introduced by low-temperature nitridation. Supersaturated nitrogen atoms in the S-phase layer can effectively prevent the decrease in pH of the corrosive medium and accelerate the alloy repassivation kinetics. However, when the bending stress was increased to 205 and 246 MPa (100 pct YS, 120 pct YS), macroscopic cracks were observed in the presence of both tensile stress and a corrosive medium.

  19. Evaluation of Temperature and Stress Distribution on 2 Different Post Systems Using 3-Dimensional Finite Element Analysis.

    Science.gov (United States)

    Değer, Yalçın; Adigüzel, Özkan; Yiğit Özer, Senem; Kaya, Sadullah; Seyfioğlu Polat, Zelal; Bozyel, Bejna

    2015-11-29

    BACKGROUND The mouth is exposed to thermal irritation from hot and cold food and drinks. Thermal changes in the oral cavity produce expansions and contractions in tooth structures and restorative materials. The aim of this study was to investigate the effect of temperature and stress distribution on 2 different post systems using the 3-dimensional (3D) finite element method. MATERIAL AND METHODS The 3D finite element model shows a labio-lingual cross-sectional view of the endodontically treated upper right central incisor and supporting periodontal ligament with bone structures. Stainless steel and glass fiber post systems with different physical and thermal properties were modelled in the tooth restored with composite core and ceramic crown. We placed 100 N static vertical occlusal loading onto the center of the incisal surface of the tooth. Thermal loads of 0°C and 65°C were applied on the model for 5 s. Temperature and thermal stresses were determined on the labio-lingual section of the model at 6 different points. RESULTS The distribution of stress, including thermal stress values, was calculated using 3D finite element analysis. The stainless steel post system produced more temperature and thermal stresses on the restorative materials, tooth structures, and posts than did the glass fiber reinforced composite posts. CONCLUSIONS Thermal changes generated stresses in the restorative materials, tooth, and supporting structures.

  20. Antagonistic effects of drought and sand burial enable the survival of the biocrust moss Bryum argenteum in an arid sandy desert

    Directory of Open Access Journals (Sweden)

    R. Jia

    2018-02-01

    Full Text Available Biocrust moss is an essential soil surface bio-cover. It can represent the latest succession stage among the diverse range of surface-dwelling cryptogams (e.g., cyanobacteria, green algae, and lichen, which are also referred to as biocrusts, and it can make a major contribution to soil stability and fertility in many arid sandy desert ecosystems. The soil surface represents a very large ecological niche that is poikilohydric in nature. Biocrust moss is therefore highly susceptible to drought and sand burial, which are two ubiquitous stressors in arid sandy deserts. However, little information is available regarding the mechanism by which biocrust moss can survive and flourish in these habitats when stressed simultaneously by the two stressors. The combined effects of drought and sand burial were evaluated in a field experiment using the predominant biocrust moss, Bryum argenteum Hedw., in the Tengger Desert, China. Drought was simulated by applying distilled water in three artificial rainfall regimes at 8-day intervals in spring and autumn: 4 and 6 mm (average rainfall, control, 2 and 3 mm (double drought, and 1 and 1.5 mm (4-fold drought, respectively. The effect of sand burial was determined by applying six treatments, i.e., sand depths of 0 (control, 0.5, 1, 2, 4, and 10 mm. The four parameters of chlorophyll a content, PSII photochemical efficiency, regeneration potential, and shoot upgrowth were evaluated in the moss. It was found that the combined effects of drought and sand burial did not exacerbate the single negative effects of the four parameters tested. Drought significantly ameliorated the negative effects of deep-sand burial on the retention of chlorophyll a content, PSII photochemical efficiency, and the regeneration potential of B. argenteum. Sand burial diminished and even reversed the negative effects of drought on the maintenance of chlorophyll a content, PSII photochemical efficiency, and regeneration potential

  1. Antagonistic effects of drought and sand burial enable the survival of the biocrust moss Bryum argenteum in an arid sandy desert

    Science.gov (United States)

    Jia, Rongliang; Zhao, Yun; Gao, Yanhong; Hui, Rong; Yang, Haotian; Wang, Zenru; Li, Yixuan

    2018-02-01

    Biocrust moss is an essential soil surface bio-cover. It can represent the latest succession stage among the diverse range of surface-dwelling cryptogams (e.g., cyanobacteria, green algae, and lichen, which are also referred to as biocrusts), and it can make a major contribution to soil stability and fertility in many arid sandy desert ecosystems. The soil surface represents a very large ecological niche that is poikilohydric in nature. Biocrust moss is therefore highly susceptible to drought and sand burial, which are two ubiquitous stressors in arid sandy deserts. However, little information is available regarding the mechanism by which biocrust moss can survive and flourish in these habitats when stressed simultaneously by the two stressors. The combined effects of drought and sand burial were evaluated in a field experiment using the predominant biocrust moss, Bryum argenteum Hedw., in the Tengger Desert, China. Drought was simulated by applying distilled water in three artificial rainfall regimes at 8-day intervals in spring and autumn: 4 and 6 mm (average rainfall, control), 2 and 3 mm (double drought), and 1 and 1.5 mm (4-fold drought), respectively. The effect of sand burial was determined by applying six treatments, i.e., sand depths of 0 (control), 0.5, 1, 2, 4, and 10 mm. The four parameters of chlorophyll a content, PSII photochemical efficiency, regeneration potential, and shoot upgrowth were evaluated in the moss. It was found that the combined effects of drought and sand burial did not exacerbate the single negative effects of the four parameters tested. Drought significantly ameliorated the negative effects of deep-sand burial on the retention of chlorophyll a content, PSII photochemical efficiency, and the regeneration potential of B. argenteum. Sand burial diminished and even reversed the negative effects of drought on the maintenance of chlorophyll a content, PSII photochemical efficiency, and regeneration potential. Although drought and sand

  2. Variable Temperature Stress in the Nematode Caenorhabditis elegans (Maupas and Its Implications for Sensitivity to an Additional Chemical Stressor.

    Directory of Open Access Journals (Sweden)

    Nina Cedergreen

    Full Text Available A wealth of studies has investigated how chemical sensitivity is affected by temperature, however, almost always under different constant rather than more realistic fluctuating regimes. Here we compared how the nematode Caenorhabditis elegans responds to copper at constant temperatures (8-24°C and under fluctuation conditions of low (±4°C and high (±8°C amplitude (averages of 12, 16, 20°C and 16°C respectively. The DEBkiss model was used to interpret effects on energy budgets. Increasing constant temperature from 12-24°C reduced time to first egg, life-span and population growth rates consistent with temperature driven metabolic rate change. Responses at 8°C did not, however, accord with this pattern (including a deviation from the Temperature Size Rule, identifying a cold stress effect. High amplitude variation and low amplitude variation around a mean temperature of 12°C impacted reproduction and body size compared to nematodes kept at the matching average constant temperatures. Copper exposure affected reproduction, body size and life-span and consequently population growth. Sensitivity to copper (EC50 values, was similar at intermediate temperatures (12, 16, 20°C and higher at 24°C and especially the innately stressful 8°C condition. Temperature variation did not increase copper sensitivity. Indeed under variable conditions including time at the stressful 8°C condition, sensitivity was reduced. DEBkiss identified increased maintenance costs and increased assimilation as possible mechanisms for cold and higher copper concentration effects. Model analysis of combined variable temperature effects, however, demonstrated no additional joint stressor response. Hence, concerns that exposure to temperature fluctuations may sensitise species to co-stressor effects seem unfounded in this case.

  3. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress*

    OpenAIRE

    Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia

    2009-01-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 °C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it en...

  4. Stress heterogeneity analysis by X-ray diffraction in the 16MND5 bainitic pressure vessel steel at low temperatures

    International Nuclear Information System (INIS)

    Pesci, R.; Inal, K.; Berveiller, M.

    2004-01-01

    The 16MND5 bainitic steel being a two-phase material, the X-Ray Diffraction (XRD) is the most efficient tool to determine the stress states in the ferritic phase. Coupled to tensile tests at low temperatures [96 deg C; -60 deg C], this technique shows the heterogeneity of strains for each phase and each crystallographic orientation. A multi-scale polycrystalline modeling is developed concurrently with these experimental measurements: it takes into account the effects of temperature on the stress states in each phase, enables to calculate the lattice strains ε φψ and also includes a cleavage fracture criterion. (authors)

  5. The Effect of Grain Size and Strain on the Tensile Flow Stress of Aluminium at Room Temperature

    DEFF Research Database (Denmark)

    Hansen, Niels

    1977-01-01

    Tensile-stress-strain data over a strain range from 0.2 to 30% were obtained at room temperature for 99.999 and 99.5% aluminium as a function of grain size. The yield stress-grain size relationship can be expressed by a Petch-Hall relation with approximately the same slope for the two materials....... The flow stress-grain size relationship can adequately be expressed by a modified Petch-Hall relation; for 99.999% aluminium material the slope increases with strain through a maximum around 15–20%, whereas for 99.5% aluminium the slope decreases with the strain to zero at strains about 10%. The flow...... stress-grain size relationship was analyzed in terms of matrix strengthening and grain boundary strengthening according to the dislocation concept of Ashby. At intermediate strains this approach gives a good description of the effect of strain, grain size and purity on the flow stress....

  6. The probability distribution of intergranular stress corrosion cracking life for sensitized 304 stainless steels in high temperature, high purity water

    International Nuclear Information System (INIS)

    Akashi, Masatsune; Kenjyo, Takao; Matsukura, Shinji; Kawamoto, Teruaki

    1984-01-01

    In order to discuss the probability distribution of intergranular stress corrsion carcking life for sensitized 304 stainless steels, a series of the creviced bent beem (CBB) and the uni-axial constant load tests were carried out in oxygenated high temperature, high purity water. The following concludions were resulted; (1) The initiation process of intergranular stress corrosion cracking has been assumed to be approximated by the Poisson stochastic process, based on the CBB test results. (2) The probability distribution of intergranular stress corrosion cracking life may consequently be approximated by the exponential probability distribution. (3) The experimental data could be fitted to the exponential probability distribution. (author)

  7. Two Catacombs of Late Sarmatian Time From Pashkovsky Burial Mound no. 2

    OpenAIRE

    Limberis Natalya Yuryevna; Marchenko Ivan Ivanovich

    2015-01-01

    The article deals with two burials from the Kuban basin region excavated in Pashkovsky burial mound no. 2 belonging to Maeotian Pashkovskoe ancient settlement. The burials were made in catacombs of similar construction and orientation. The narrow grave entrances and grave chambers are situated in-line. The grave chambers of the catacombs adjoin one other that probably was the reason for plunder of a little earlier burial no. 2. There were the complete horse skeleton, the cow skull and the she...

  8. Measurement of Temperature and Relative Humidity with Polymer Optical Fiber Sensors Based on the Induced Stress-Optic Effect.

    Science.gov (United States)

    Leal-Junior, Arnaldo; Frizera-Neto, Anselmo; Marques, Carlos; Pontes, Maria José

    2018-03-20

    This paper presents a system capable of measuring temperature and relative humidity with polymer optical fiber (POF) sensors. The sensors are based on variations of the Young's and shear moduli of the POF with variations in temperature and relative humidity. The system comprises two POFs, each with a predefined torsion stress that resulted in a variation in the fiber refractive index due to the stress-optic effect. Because there is a correlation between stress and material properties, the variation in temperature and humidity causes a variation in the fiber's stress, which leads to variations in the fiber refractive index. Only two photodiodes comprise the sensor interrogation, resulting in a simple and low-cost system capable of measuring humidity in the range of 5-97% and temperature in the range of 21-46 °C. The root mean squared errors (RMSEs) between the proposed sensors and the reference were 1.12 °C and 1.36% for the measurements of temperature and relative humidity, respectively. In addition, fiber etching resulted in a sensor with a 2 s response time for a relative humidity variation of 10%, which is one of the lowest recorded response times for intrinsic POF humidity sensors.

  9. Study on Real-Time Simulation Analysis and Inverse Analysis System for Temperature and Stress of Concrete Dam

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2015-01-01

    Full Text Available In the concrete dam construction, it is very necessary to strengthen the real-time monitoring and scientific management of concrete temperature control. This paper constructs the analysis and inverse analysis system of temperature stress simulation, which is based on various useful data collected in real time in the process of concrete construction. The system can produce automatically data file of temperature and stress calculation and then achieve the remote real-time simulation calculation of temperature stress by using high performance computing techniques, so the inverse analysis can be carried out based on a basis of monitoring data in the database; it fulfills the automatic feedback calculation according to the error requirement and generates the corresponding curve and chart after the automatic processing and analysis of corresponding results. The system realizes the automation and intellectualization of complex data analysis and preparation work in simulation process and complex data adjustment in the inverse analysis process, which can facilitate the real-time tracking simulation and feedback analysis of concrete temperature stress in construction process and enable you to discover problems timely, take measures timely, and adjust construction scheme and can well instruct you how to ensure project quality.

  10. Habitat pollution and thermal regime modify molecular stress responses to elevated temperature in freshwater mussels (Anodonta anatina: Unionidae)

    International Nuclear Information System (INIS)

    Falfushynska, H.; Gnatyshyna, L.; Yurchak, I.; Ivanina, A.; Stoliar, O.; Sokolova, I.

    2014-01-01

    Elevated temperature and pollution are common stressors in freshwater ecosystems. We study cellular stress response to acute warming in Anodonta anatina (Unionidae) from sites with different thermal regimes and pollution levels: a pristine area and an agriculturally polluted site with normal temperature regimes (F and A, respectively) and a polluted site with elevated temperature (N) from the cooling pond of an electrical power plant. Animals were exposed to different temperatures for 14 days and stress response markers were measured in gills, digestive gland and hemocytes. Mussels from site N and A had elevated background levels of lactate dehydrogenase activity indicating higher reliance on anaerobic metabolism for ATP production and/or redox maintenance. Exposure to 25 °C and 30 °C induced oxidative stress (indicated by elevated levels of lipid peroxidation products) in digestive gland and gills of mussels from A and F sites, while in mussels from N sites elevated oxidative stress was only apparent at 30 °C. Temperature-induced changes in levels of antioxidants (superoxide dismutase, metallothioneins and glutathione) were tissue- and population-specific. Acute warming led to destabilization of lysosomal membranes and increased frequencies of nuclear lesions in mussels from F and A sites but not in their counterparts from N site. Elevated temperature led to an increase in the frequency of micronuclei in hemocytes in mussels from F and A sites at 25 °C and 30 °C and in mussels from N site at 30 °C. The mussels from N site also demonstrated better survival at elevated temperature (30 °C) than their counterparts from the F and A sites. Taken together, these data indicate that long-term acclimation and/or adaptation of A. anatina to elevated temperatures result in increased thermotolerance and alleviate stress response to moderate temperature rise. In contrast, extreme warming (30 °C) is harmful to mussels from all populations indicating limit to this induced

  11. Habitat pollution and thermal regime modify molecular stress responses to elevated temperature in freshwater mussels (Anodonta anatina: Unionidae)

    Energy Technology Data Exchange (ETDEWEB)

    Falfushynska, H.; Gnatyshyna, L.; Yurchak, I. [Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, Kryvonosa Str 2, 46027 Ternopil (Ukraine); Ivanina, A. [Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States); Stoliar, O. [Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, Kryvonosa Str 2, 46027 Ternopil (Ukraine); Sokolova, I., E-mail: isokolov@uncc.edu [Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States)

    2014-12-01

    Elevated temperature and pollution are common stressors in freshwater ecosystems. We study cellular stress response to acute warming in Anodonta anatina (Unionidae) from sites with different thermal regimes and pollution levels: a pristine area and an agriculturally polluted site with normal temperature regimes (F and A, respectively) and a polluted site with elevated temperature (N) from the cooling pond of an electrical power plant. Animals were exposed to different temperatures for 14 days and stress response markers were measured in gills, digestive gland and hemocytes. Mussels from site N and A had elevated background levels of lactate dehydrogenase activity indicating higher reliance on anaerobic metabolism for ATP production and/or redox maintenance. Exposure to 25 °C and 30 °C induced oxidative stress (indicated by elevated levels of lipid peroxidation products) in digestive gland and gills of mussels from A and F sites, while in mussels from N sites elevated oxidative stress was only apparent at 30 °C. Temperature-induced changes in levels of antioxidants (superoxide dismutase, metallothioneins and glutathione) were tissue- and population-specific. Acute warming led to destabilization of lysosomal membranes and increased frequencies of nuclear lesions in mussels from F and A sites but not in their counterparts from N site. Elevated temperature led to an increase in the frequency of micronuclei in hemocytes in mussels from F and A sites at 25 °C and 30 °C and in mussels from N site at 30 °C. The mussels from N site also demonstrated better survival at elevated temperature (30 °C) than their counterparts from the F and A sites. Taken together, these data indicate that long-term acclimation and/or adaptation of A. anatina to elevated temperatures result in increased thermotolerance and alleviate stress response to moderate temperature rise. In contrast, extreme warming (30 °C) is harmful to mussels from all populations indicating limit to this induced

  12. Mesolithic burial place in La Martina Cave (Dinant, Belgium)

    International Nuclear Information System (INIS)

    Dewez, M.; Gilot, E.; Groessens-Van-Dyck, M.C.; Cordy, J.M.

    1995-01-01

    The ''La Martina'' cave is located near Dinant (Belgium). Although the sediments had been shoveled out in the mid XIXth century, a calcic breccia has provided prehistoric bones. We can distinguish a Pleistocene fauna with cave bear, one Mesolithic burial place with two cromagnoid skeletons, from the 6th millennium BC, and some Holocene faunal remains. (authors). 7 refs

  13. Scale and distribution of marine carbonate burial dissolution pores

    Directory of Open Access Journals (Sweden)

    Anjiang Shen

    2016-06-01

    Full Text Available It is gradually accepted that porosity can be created in burial settings via dissolution by organic acid; TSR derived or hydrothermal fluids. The role of deep-buried carbonate reservoirs is becoming more and more important since the degree and difficulty in petroleum exploration of shallow strata are increasing. A profound understanding of the development scale and prediction of the deep-buried carbonate reservoirs is economically crucial. In addition to the formation mechanism, scale and distribution of burial dissolution pores in burial settings are focused on in recent studies. This paper is based on case studies of deep-buried (>4500 m carbonate reservoirs from the Tarim Basin and Sichuan Basin. Case studies mentioned includes dissolution simulation experiments proposes that an open system is of crucial importance in the development of large-scale burial dissolution pores, the distribution pattern of which is controlled by lithology, pre-existing porosity, and pore throat structures. These findings provided the basis for evaluation and prediction of deep-buried carbonate reservoirs.

  14. Waste analysis plan for the low-level burial grounds

    Energy Technology Data Exchange (ETDEWEB)

    Haas, C.R.

    1996-09-19

    This waste analysis plan (WAP) has been prepared for the Low-Level Burial Grounds (LLBG) which are located in the 200 East and West Areas of the Hanford Facility, Richland, Washington. This WAP documents the methods used to characterize, and obtain and analyze representative samples of waste managed at this unit.

  15. Waste analysis plan for the low-level burial grounds

    International Nuclear Information System (INIS)

    Barnes, B.M.

    1996-01-01

    This waste analysis plan (WAP) has been prepared for the Low-Level Burial Grounds that are located in the 200 East and 200 West Areas of the Hanford Facility, Richland, Washington. This WAP documents the methods used to characterize and obtain and analyze representative samples of waste managed at this unit

  16. Redefining kin and family social relations: burial societies and ...

    African Journals Online (AJOL)

    The omnipresence of death and dying in Botswana (due to the AIDS pandemic, social victimization, road-related carnage and so on), does not necessarily precipitate despondency; instead it underwrites commitments by members of burial societies to new sensibilities and to imaginative interventions that regenerate, rather ...

  17. Chemical and Mechanical processes during burial diagenesis of chalk

    DEFF Research Database (Denmark)

    Borre, Mai Kirstine; Lind, Ida

    1998-01-01

    Burial diagenesis of chalk is a combination of mechanical compaction and chemical recrystallization as well as cementation. We have predicted the characteristic trends in specific surface resulting from these processes. The specific surface is normally measured by nitrogen adsorption but is here...

  18. Effect of temperature and stress on the structure and creep parameters of Pb-2 at%Sb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ganainy, G.S. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Mostafa, M.T.; Nagy, M.R. [Ain Shams Univ., Cairo (Egypt). Faculty of Education

    1998-01-16

    The transient and steady state creep parameters of Pb-2 at% Sb alloy are determined in the temperature range from 443 to 503 K. The transient creep parameters {beta} and n increase with working temperature and applied stress and have values changing from 43 x 10{sup -4} to 335 x 10{sup -4} and from 0.46 to 0.79, respectively. The strain rate sensitivity parameter m changes from 0.12 to 0.2 which points to a cross slipping dislocation mechanism. The activation energies of both transient and steady state creep are calculated. In the low temperature range (443 to 473 K), the steady state activation energy is found to be stress dependent. The X-ray analysis supports that relaxation of the internal lattice strain takes place at the transformation temperature (473 K). (orig.) 17 refs.

  19. 25 CFR 20.325 - Who can apply for Burial Assistance?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who can apply for Burial Assistance? 20.325 Section 20.325 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR HUMAN SERVICES FINANCIAL ASSISTANCE AND SOCIAL SERVICES PROGRAMS Direct Assistance Burial Assistance § 20.325 Who can apply for Burial...

  20. 25 CFR 20.326 - Does Burial Assistance cover transportation costs?

    Science.gov (United States)

    2010-04-01

    ... ASSISTANCE AND SOCIAL SERVICES PROGRAMS Direct Assistance Burial Assistance § 20.326 Does Burial Assistance... 25 Indians 1 2010-04-01 2010-04-01 false Does Burial Assistance cover transportation costs? 20.326... because of extenuating circumstances, the social services worker can pay the added charge. To do this, the...

  1. Environmental analysis burial of offsite low-level waste at SRP

    International Nuclear Information System (INIS)

    Poe, W.L.; Moyer, R.A.

    1980-12-01

    The environmental effects of receipt and burial of low-level naval waste generated at Department of Energy Laboratories are assessed in this environmental analysis. Through 1979, this low-level DOE waste was sent to the NRC-licensed burial ground operated by Chem-Nuclear Systems, Inc., at Barnwell, South Carolina. DOE announced on October 26, 1979, that DOE-generated low-level waste would no longer be buried at commercial waste burial sites. SRP was selected to receive the naval waste described in this analysis. Receipt and burial of these wastes will have a negligible effect on SRP's environment and increase only slightly the environmental effects of the SRP operations discussed in the EIS on SRP waste management operations. The environmental effects of burial of this waste at Chem-Nuclear Burial Ground or at the SRP Burial Ground are described in this environmental analysis to permit assessment of incremental effects caused by the decision to bury this naval waste in the SRP Burial Ground rather than in the Barnwell Burial Ground. The radiological effects from burial of this waste in either the SRP or Chem-Nuclear Burial Ground are very small when compared to those from natural background radiation or to the annual population dose commitment from operation of SRP. The environmental effects of burial at SRP to dose commitments normally received by the population surrounding SRP are compared

  2. Funeral dress and textiles in 17th and 19th century burials in Ostrobothnia, Finland

    NARCIS (Netherlands)

    Lipkin, S.; Vajanto, K.; Kallio-Seppä, T.; Kuokkanen, T.; Niinimäki, S.; Väre, T.; van Bommel, M.; Grömer, K.; Pritchard, F.

    2015-01-01

    The 17th-19th-century burial materials from northern Ostrobothnia are studied in order to consider the value, origin and meaning of textiles especially in child burials. The focus is on the preservation, quality and dyes of burial textiles unearthed at the yard of Oulu Cathedral as well as the

  3. The Sociological Essence of Music in Burial: An Analysis of Akwa ...

    African Journals Online (AJOL)

    The type of research methodology to be used in this paper would involve interviews and critical analysis on Akwa Oke-Nwanyi songs on some selected burials. This paper therefore looked at the sociological essence of burial music by taking a critical analysis of Akwa-Oke Nwaanyi. Key Word: Music in Burials; Akwa ...

  4. The kink-pair mechanism and low-temperature flow-stress behaviour of strontium titanate single crystals

    International Nuclear Information System (INIS)

    Castillo-Rodriguez, M.; Sigle, W.

    2011-01-01

    The mechanical behaviour of strontium titanate exhibits a remarkable behaviour at low temperature, in the so-called regime A, where the flow stress experiences two different temperature dependences separated by a noticeably abrupt drop in between. The dislocation microstructure was investigated and, by making adequate use of the kink-pair model, we interpret this behaviour as a transition from the short- to the long-segment limit of kink-pair formation. The fit parameters are found to be physically sound.

  5. Spatial and temporal patterns of stream burial and its effect on habitat connectivity across headwater stream communities of the Potomac River Basin, USA

    Science.gov (United States)

    Weitzell, R.; Guinn, S. M.; Elmore, A. J.

    2012-12-01

    The process of directing streams into culverts, pipes, or concrete-lined ditches during urbanization, known as stream burial, alters the primary physical, chemical, and biological processes of streams. Knowledge of the cumulative impacts of reduced structure and ecological function within buried stream networks is crucial for informing management of stream ecosystems, in light of continued growth in urban areas, and the uncertain response of freshwater ecosystems to the stresses of global climate change. To address this need, we utilized recently improved stream maps for the Potomac River Basin (PRB) to describe the extent and severity of stream burial across the basin. Observations of stream burial made from high resolution aerial photographs (>1% of total basin area) and a decision tree using spatial statistics from impervious cover data were used to predict stream burial at 4 time-steps (1975, 1990, 2001, 2006). Of the roughly 95,500 kilometers (km) of stream in the PRB, approximately 4551 km (4.76%) were buried by urban development as of 2001. Analysis of county-level burial trends shows differential patterns in the timing and rates of headwater stream burial, which may be due to local development policies, topographical constraints, and/or time since development. Consistently higher rates of stream burial were observed for small streams, decreasing with stream order. Headwater streams (1st-2nd order) are disproportionately affected, with burial rates continuing to increase over time in relation to larger stream orders. Beyond simple habitat loss, headwater burial decreases connectivity among headwater populations and habitats, with potential to affect a wide range of important ecological processes. To quantify changes to regional headwater connectivity we applied a connectivity model based on electrical circuit theory. Circuit-theoretical models function by treating the landscape as a resistance surface, representing hypothesized relationships between

  6. A comparative proteomic analysis of responses to high temperature stress in hypocotyl of Canola (Brassica napus L.).

    Science.gov (United States)

    Ismaili, Ahmad; Salavati, Afshin; Mohammadi, Payam Pour

    2014-01-01

    High temperature stress, especially on the early season of plant growth stages, is an agricultural problem in many areas in the world. A temporary or continually high temperature leads to a set of morphological, biochemical and physiological changes in plants, which consequently reduces the plant growth and development and finally may cause a severe reduction in economic yield. The main goal of this study was to assess plant response to high temperature stress (HTS) in early seedling of canola. This study is the first experiment on the effect of heat stress on proteome of canola. In the present research, a proteomics approach was used to evaluate the effects of high temperature stress, including 45 °C day/34 °C night for 2, 6 and 12 hour, on early seedling stage (2-day old) of canola. Proteins were isolated from hypocotyl and separated by two-dimensional polyacrylamide gel electrophoresis. Out of 381 protein spots, 28 and 34 proteins were significantly down- and up-regulated, respectively. The trend of mRNA expression for sucrose binding protein, a scorbate peroxidase and triosephosphateisomerase, was in accordance with their trend at translation level. Results of this study suggest that the up-regulation of proteins involved in cellular traffic, energy and metabolism, and down-regulation of some proteins involved in disease and defense, protein synthesis and signal transduction could be the main reason of physiological and morphological responses to high temperature stress. The observed increases in the level of ascorbate peroxidase protein and mRNA expression in canola hypocotyl in response to HTS suggests that ascorbate peroxidase is a short term high temperature stress response protein and is thus a candidate for gene modification strategies aimed at producing high temperature canola varieties. These results also suggest that the up regulation of protein involved in energy and metabolism in response to the heat stress can use most of nutritive reserves in

  7. Sarmatian Burials Near the Astanino Village in the Eastern Crimea

    Directory of Open Access Journals (Sweden)

    Kropotov Viktor Valeryevich

    2015-06-01

    Full Text Available The present article contains the materials of two Sarmatian burials that had been studied in 1966-1967 years by the Kerch expedition of Institute of Archeology of Academy of Sciences of Ukraine (the chief of expedition – A.M. Leskov in the Astanino village in the Eastern Crimea. These burials had been made on small depth in embankments of barrows of the bronze epoch, therefore it is not possible to track contours of funeral constructions. The dead were laid on their backs, heads turned to the North and the North-West. The utensils buried in the same tombs included two ceramic gray-clay pelikes, two gray-clay bowls, a red-gloss vessel, a red-clay pottery, a set of glass and cornelian beads, and the Egyptian faience beads. These things allow to exactly date the investigated complexes within the second half of the 1st century BC – the beginnings of the 1st century AD. The main distinctive characteristics of Early-Sarmatian burials of Northern Pontic region consist in the use of already existing barrows for burial places, orientations of the dead in the Northern sector, the insignificant depth of burials. Therefore published monuments should be also referred to them. A small number of such complexes with their distribution on the quite big territory between the Don and Dnepr rivers testify to the low density of the nomadic population at that time. The antique sources of the end of the 2nd – 1st centuries BC mention the presence of Roxolani in the given region. The described complexes supplement our poor knowledge of Sarmatian antiquities of the Eastern Crimea and specify the direct contacts of nomads of Northern Pontic region to the antique centers, in immediate proximity from which they had been located.

  8. Quasi-100 ky glacial-interglacial cycles triggered by subglacial burial carbon release

    Directory of Open Access Journals (Sweden)

    N. Zeng

    2007-01-01

    Full Text Available A mechanism is proposed in which climate, carbon cycle and icesheets interact with each other to produce a feedback that can lead to quasi-100 ky glacial-interglacial cycles. A central process is the burial and preservation of organic carbon by icesheets which contributes to the observed glacial-interglacial CO2 change (the glacial burial hypothesis, Zeng, 2003. Allowing carbon cycle to interact with physical climate, here I further hypothesize that deglaciation can be triggered by the ejection of glacial burial carbon when a major icesheet grows to sufficiently large size after a prolonged glaciation so that subglacial transport becomes significant. Glacial inception may be initiated by CO2 drawdown due to a relaxation from a high but transient interglacial CO2 value as the land-originated CO2 invades into deep ocean via thermohaline circulation and CaCO3 compensation. Also important for glacial inception may be the CO2 uptake by vegetation and soil regrowth in the previously ice-covered regions. When tested in a fully coupled Earth system model with comprehensive carbon cycle components and semi-empirical physical climate components, it produced under certain parameter regimes self-sustaining glacial-interglacial cycles with durations of 93 ky, CO2 changes of 90 ppmv, temperature changes of 6°C. Since the 100 ky cycles can not be easily explained by the Milankovitch astronomical forcing alone, this carbon-climate-icesheet mechanism provides a strong feedback that could interact with external forcings to produce the major observed Quaternary climatic variations. It is speculated that some glacial terminations may be triggered by this internal feedback while others by orbital forcing. Some observable consequences are highlighted that may support or falsify the theory.

  9. Long-term creep behavior of high-temperature gas turbine materials under constant and variable stress

    International Nuclear Information System (INIS)

    Granacher, J.; Preussler, T.

    1987-01-01

    Within the framework of the documented research project, extensive creep rupture tests were carried out with characteristic, high-temperature gas turbine materials for establishment of improved design data. In the range of the main application temperatures and in stress ranges down to application-relevant values the tests extended over a period of about 40,000 hours. In addition, long-term annealing tests were carried out in the most important temperature ranges for the measurement of the density-dependent straim, which almost always manifested itself as a material contraction. Furthermore, hot tensile tests were carried out for the description of the elastoplastic short-term behavior. Several creep curves were derived from the results of the different tests with a differentiated evaluation method. On the basis of these creep curves, creep equations were set up for a series of materials which are valid in the entire examined temperature range and stress range and up to the end of the secondary creep range. Also, equations for the time-temperature-dependent description of the material contraction behavior were derived. With these equations, the high-temperature deformation behavior of the examined materials under constant creep stress can be described simply and application-oriented. (orig.) With 109 figs., 19 tabs., 77 refs [de

  10. Clinical studies of the vibration syndrome using a cold stress test measuring finger temperature.

    Science.gov (United States)

    Gautherie, M

    1995-01-01

    Since nine years multicentre, transversal and longitudinal clinical studies on hand-arm, vibration-exposed patients are being performed in cooperation with French occupational medicine centers and social security institutions. These studies are based upon current clinical assessment and standardized, temperature-measuring cooling tests. Data acquisition uses a portable, 10-channel, micro-processor-based temperature recorder and miniature thermal sensors. Temperature is monitored at the ten finger tips continuously, before, during and after a cold stress performed in strictly controlled conditions. Data from examinations performed at outlying sites are transferred through the telephonic network to a central processing unit. Data analysis uses a specific, expert-type software procedure based upon previous clinical studies on (i) 238 "normal" subjects, and (ii) 3,046 patients with vascular disturbances of the upper extremities of various etiologies. This procedure includes a staging process which assigns each finger a class representing the degree of severity of the abnormalities of response to cold ("dysthermia") related to vascular disorders. All data processing is fully automatic and results in a printed examination report. To date, over 1,623 vibration-exposed forestry, building and mechanical workers were examined. Sixty-three per cent of patients had received high dose of vibration (daily use of chain saws, air hammers, ballast tampers over many years). Typical white finger attacks or only neurological symptoms were found in 36% and 23% of patients respectively. The rate of sever dysthermia was much higher in patients with white finger attacks (83%) than in patients without (32%). In 90% of the vibration-exposed patients, the severity of dysthermia has differed greatly from one finger to another and between hands, while in non-exposed patients with primary Raynaud syndrome the dysthermia are generally similar for all fingers but the thumbs. Of 208 forestry

  11. Effects of temperature and Mo2C layer on stress and structural properties in CVD diamond film grown on Mo foil

    International Nuclear Information System (INIS)

    Long, Fen; Wei, Qiuping; Yu, Z.M.; Luo, Jiaqi; Zhang, Xiongwei; Long, Hangyu; Wu, Xianzhe

    2013-01-01

    Highlights: •Polycrystalline diamond films were grown on Mo foil substrates by HF-CVD. •We investigated the temperature dependence of the film stress for each sample. •We show that how the thermal stress and intrinsic stress affects the total stress. •The stress of Mo foil substrate obtained by XRD was investigated in this study. •The effect of Mo 2 C interface layer for stress of multilayer system was considered. -- Abstract: Polycrystalline diamond films have been prepared by hot-filament-assisted chemical vapor deposition (HFCVD) on Mo foils. The morphology, growth rate, phase composition, element distribution and residual stress of the films at different temperature were investigated by field-emission scanning electron microscopy, Raman spectrum, field emission electron probe microanalysis and X-ray diffraction. Results show that the residual stress of the diamond films is compressive. The thermal stress plays a decisive role in the total stress, while the intrinsic stress can change the trend of the total stress. The residual stress of substrate gradually changes from tensile stress to compressive stress with the increase of the deposited temperature. A Mo 2 C interlayer is formed during deposition process, and this layer has an important influence on the stresses of films and substrates

  12. The effect of mimicking febrile temperature and drug stress on malarial development

    Directory of Open Access Journals (Sweden)

    Adisakwattana Poom

    2009-06-01

    Full Text Available Abstract Background Malaria remains one of the most important tropical diseases of human with 1–2 million deaths annually especially caused by P. falciparum. During malarial life cycle, they exposed to many environmentally stresses including wide temperature fluctuation and pharmacological active molecules. These trigger malarial evolutionarily adaptive responses. The effect of febrile temperature on malarial growth, development and drug susceptibility by mimicking patient in treatment failure before and after drug uptake was examined. Methods Sensitivities of P. falciparum to antimalarial drug (chloroquine, mefloquine, quinine and artesunate were investigated based on the incorporation of [3H] hypoxanthine into parasite nucleic acids or radioisotopic technique. The number of parasites was examined under microscope following Giemsa staining and the parasite development at the end of each phase was counted and comparison of parasite number was made. The proteome was separated, blotted and hybridized with anti-Hsp70s primary antibody. The hybridized proteins were separately digested with trypsin and identified by MALDI-TOF peptide mass fingerprint. Results The results show that febrile temperature is capable of markedly inhibiting the growth of field isolate P. falciparum but not to K1 and 3D7 standard strains. K1 and 3D7 grown under heat shock developed greater and the reinfection rate was increased up to 2-folds when compared to that of non-heat shock group. The IC50 value of K1 toward chloroquine, mefloquine and quinine under heat shock was higher than that of K1 under non-heat shock which is opposite to that of 3D7. Heat shock caused death in field isolated parasite. It was also found that the febrile temperature coped with chloroquine uptake had no effect to the development, drug sensitivity and the parasite number of K1 strain. In the opposite way, heat shock and chloroquine shows extremely effect toward 3D7 and field isolate PF91 as shown

  13. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 3 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2009 (NODC Accession 0068999)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  14. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession Number 0054501)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  15. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 4 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1981-10-31 to 2010-12-31 (NODC Accession 0087989)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  16. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  17. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 1 - Global, 4 km, Sea Surface Temperature and Related Thermal Stress Metrics for 1985-2005 (NODC Accession 0044419)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

  18. The Coral Reef Temperature Anomaly Database (CoRTAD) Version 5 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2012 (NCEI Accession 0126774)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Version 5 of the Coral Reef Temperature Anomaly Database (CoRTAD) is a global, 4 km, sea surface temperature (SST) and related thermal stress metrics dataset for...

  19. Can a canopy temperature-based stress index enhance water use efficiency in irrigated wine grape under arid conditions?

    Science.gov (United States)

    Enhancement of irrigation water use efficiency and water productivity in arid wine grape production regions is hindered by a lack of automated, real-time methods for monitoring and interpreting vine water status. A normalized, water stress index calculated from real-time vine canopy temperature meas...

  20. Hair shedding score may affect body temperature more than hair coat color during heat stress in weaned beef heifers.

    Science.gov (United States)

    The objective of this study was to evaluate the effect of hair shedding score and hair coat color on the vaginal temperature (VT) of calves during heat stress. Weaned Bos taurus beef heifers (n = 32; BW = 282 ± 6.4 kg) were assigned to a hair coat color class (BLACK; RED; or LIGHT, where LIGHT = yel...

  1. Effects of hardness and test temperature on the stress-corrosion cracking susceptibility of carbon steel in simulated BWR environment

    International Nuclear Information System (INIS)

    Nakayama, Guen; Akashi, Masatsune

    1998-01-01

    Carbon steels which are used for such as water supply line, core spray line, and clean up heat exchanger in Boiling Water Reactor (BWR) Plant, are main structural materials as well as an austenitic stainless steels, and Ni based alloys. It has been well known that carbon steels can become susceptible to stress-corrosion cracking (SCC) in BWR primary coolant water environments, i.e., the high-temperature, high-purity water containing dissolved oxygen. Nevertheless, their sensitivity of SCC appears to be markedly smaller compared to that of weld-sensitized Type 304 stainless steels, whole failure has often been observed. This paper examines the critical condition, especially effects of hardness, and temperature for the initiation of SCC by means of Slow Strain Rate Tensile (SSRT) test, and Creviced Bent Beam (CBB) test as laboratory accelerated tests. It has been shown that, (1) Intergranular stress-corrosion cracking (IGSCC) initiates over hardness of Hv 400 for single bead weld material, simulated corner weld; (2) in middle temperature domain around 160 to 190degC range, so many stress-corrosion cracks initiate, but each crack is not so deep, on the other hand, in high temperature domain, stress-corrosion cracks initiate few in number, but each cracks is developed so deep. (author)

  2. Effects of shade and feeding zilpaterol hydrochloride to finishing steers on performance, carcass quality, heat stress, mobility, and body temperature

    Science.gov (United States)

    Steers (n = 480) were used to study the effects of shade and feeding zilpaterol hydrochloride (ZH) on performance, carcass quality, heat stress, mobility, and body temperature (BT). A randomized block design with a 2 × 2 factorial arrangement of treatments was used with 4 replicates per treatment. F...

  3. Shy and bold great tits (Parus major): body temperature and breath rate in response to handling stress

    NARCIS (Netherlands)

    Carere, C.; Van Oers, K.

    2004-01-01

    A standard handling protocol was used to test the hypothesis that boldness predicts stress responsiveness in body temperature and breath rate. Great tit (Parus major) nestlings were taken from the field, hand reared until independence, and their response to a novel object was assessed. At the age of

  4. Variable content and distribution of arabinogalactan proteins in banana (Musa spp.) under low temperature stress.

    Science.gov (United States)

    Yan, Yonglian; Takáč, Tomáš; Li, Xiaoquan; Chen, Houbin; Wang, Yingying; Xu, Enfeng; Xie, Ling; Su, Zhaohua; Šamaj, Jozef; Xu, Chunxiang

    2015-01-01

    Information on the spatial distribution of arabinogalactan proteins (AGPs) in plant organs and tissues during plant reactions to low temperature (LT) is limited. In this study, the extracellular distribution of AGPs in banana leaves and roots, and their changes under LT stress were investigated in two genotypes differing in chilling tolerance, by immuno-techniques using 17 monoclonal antibodies against different AGP epitopes. Changes in total classical AGPs in banana leaves were also tested. The results showed that AGP epitopes recognized by JIM4, JIM14, JIM16, and CCRC-M32 antibodies were primarily distributed in leaf veins, while those recognized by JIM8, JIM13, JIM15, and PN16.4B4 antibodies exhibited predominant sclerenchymal localization. Epitopes recognized by LM2, LM14, and MAC207 antibodies were distributed in both epidermal and mesophyll cells. Both genotypes accumulated classical AGPs in leaves under LT treatment, and the chilling tolerant genotype contained higher classical AGPs at each temperature treatment. The abundance of JIM4 and JIM16 epitopes in the chilling-sensitive genotype decreased slightly after LT treatment, and this trend was opposite for the tolerant one. LT induced accumulation of LM2- and LM14-immunoreactive AGPs in the tolerant genotype compared to the sensitive one, especially in phloem and mesophyll cells. These epitopes thus might play important roles in banana LT tolerance. Different AGP components also showed differential distribution patterns in banana roots. In general, banana roots started to accumulate AGPs under LT treatment earlier than leaves. The levels of AGPs recognized by MAC207 and JIM13 antibodies in the control roots of the tolerant genotype were higher than in the chilling sensitive one. Furthermore, the chilling tolerant genotype showed high immuno-reactivity against JIM13 antibody. These results indicate that several AGPs are likely involved in banana tolerance to chilling injury.

  5. In vitro degradation kinetics of pure PLA and Mg/PLA composite: Effects of immersion temperature and compression stress.

    Science.gov (United States)

    Li, Xuan; Chu, Chenglin; Wei, Yalin; Qi, Chenxi; Bai, Jing; Guo, Chao; Xue, Feng; Lin, Pinghua; Chu, Paul K

    2017-01-15

    The effects of the immersion temperature and compression stress on the in vitro degradation behavior of pure poly-lactic acid (pure-PLA) and PLA-based composite unidirectionally reinforced with micro-arc oxidized magnesium alloy wires (Mg/PLA or MAO-MAWs/PLA) are investigated. The degradation kinetics of pure-PLA and the PLA matrix in MAO-MAWs/PLA exhibit an Arrhenius-type behavior. For the composite, the synergic degradation of MAO-MAWs maintains a steady pH and mitigates the degradation of PLA matrix during immersion. However, the external compression stress decreases the activation energy (E a ) and pre-exponential factor (k 0 ) consequently increasing the degradation rate of PLA. Under a compression stress of 1MPa, E a and k 0 of pure PLA are 57.54kJ/mol and 9.74×10 7 day -1 , respectively, but 65.5kJ/mol and 9.81×10 8 day -1 for the PLA matrix in the composite. Accelerated tests are conducted in rising immersion temperature in order to shorten the experimental time. Our analysis indicates there are well-defined relationships between the bending strength of the specimens and the PLA molecular weight during immersion, which are independent of the degradation temperature and external compression stress. Finally, a numerical model is established to elucidate the relationship of bending strength, the PLA molecular weight, activation energy, immersion time and temperature. We systematically evaluate the effects of compression stress and temperature on the degradation properties of two materials: (pure-PLA) and MAO-MAWs/PLA (or Mg/PLA). The initial in vitro degradation kinetics of the unstressed or stressed pure-PLA and MAO-MAWs/PLA composite is confirmed to be Arrhenius-like. MAO-MAWs and external compression stress would influence the degradation activation energy (E a ) and pre-exponential factor (k 0 ) of PLA, and we noticed there is a linear relationship between E a and ln k 0 . Thereafter, we noticed that Mg 2+ , not H + , plays a significant role on the

  6. Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses

    DEFF Research Database (Denmark)

    Caspeta, Luis; Nielsen, Jens

    2015-01-01

    adaptive laboratory evolution, we previously isolated seven Saccharomyces cerevisiae strains with improved growth at 40°C. Here, we show that genetic adaptations to high temperature caused a growth trade-off at ancestral temperatures, reduced cellular functions, and improved tolerance of other stresses...... in the ancestral strain. The latter is an advantageous attribute for acquiring thermotolerance and correlates with the reduction of yeast functions associated with loss of respiration capacity. This trait caused glycerol overproduction that was associated with the growth trade-off at ancestral temperatures...

  7. Incision of the Yangtze River at the First Bend Determined by Three-Nuclide Burial Dating

    Science.gov (United States)

    McPhillips, D. F.; Hoke, G. D.; Rood, D. H.; Bierman, P. R.

    2015-12-01

    On the southeast margin of the Tibetan Plateau, the evolution of the Yangtze River and its major tributaries has become an important source of data for investigating geodynamics. In particular, the timing of river incision is frequently interpreted as a proxy for the timing of surface uplift in the absence of structural evidence. We investigate the timing of the incision of the gorge at the First Bend using cosmogenic nuclide burial dating of coarse, quartz sediments from caves. Sediments were deposited when the caves were near river level and subsequently abandoned as the river incised. To resolve burial ages >5 Ma, we measured the radionuclides 10Be and 26Al, and the stable nuclide 21Ne. Results from 4 caves show that 26Al and 10Be concentrations are an order of magnitude lower in abandoned cave samples than in a river-level cave sample where deposition is active (10Be: 1.3x104 and 3.4x105 at/g). In contrast, 26Al/10Be ratios in all caves are ≥6.2 and indistinguishable within error. 21Ne concentrations range from 2.1x106 to 7.8x106 at/g. The results are consistent with an old age for the abandoned cave deposits, such that most of the radionuclides initially present have decayed and the concentrations that we measure today are the result of millions of years of exposure to muons. We solve for burial ages, taking into account in situ muogenic production, and find that the majority of the gorge (1 km) was likely incised between ~12 and 9 Ma. The results also require that the rate of river incision declined after the gorge was cut below the lowest elevation cave at 9 Ma. Inverse modeling of published low-temperature thermochronology (Ouimet et al., 2010) supports our burial age results. River capture near the First Bend, which likely integrated the modern Yangtze, likely occurred prior to the mid-Miocene incision of the gorge. In view of the geographic position of the First Bend—just downslope from the southeast margin of the Plateau—it is difficult to explain

  8. Direct burial and vault emplacement data quality comparison at Dotson Ranch, New Mexico

    Science.gov (United States)

    Beaudoin, B. C.; Aderhold, K.; Anderson, K.; Pfeifer, M.; Parker, T.; Miller, P. E.; Slad, G. W.; Reusch, A.

    2013-12-01

    noise levels are similar at all sensors and are likely due to cultural activity and temperature fluctuations. The conclusion from this study is that the shallow vault emplacement method does not provide significant improvement in data quality compared to direct burial emplacement method. Further experiments are underway in a less noisy environment at Poker Flat Research Range in Alaska.

  9. Improved austenitic stainless steel for high temperature applications. [Improved stress-rupture properties

    Science.gov (United States)

    Not Available

    This invention describes a composition for an austenitic stainless steel which has been found to exhibit improved high temperature stress rupture properties. The composition of this alloy is about (in wt. %): 12.5 to 14.5 Cr; 14.5 to 16.5 Ni; 1.5 to 2.5 Mo; 1.5 to 2.5 Mn; 0.1 to 0.4 Ti; 0.02 to 0.08 C; 0.5 to 1.0 Si; 0.01 maximum, N; 0.02 to 0.08 P; 0.002 to 0.008 B; 0.004-0.010 S; 0.02-0.05 Nb; .01-.05 V; 0.005-0.02 Ta; 0.02-0.05 Al; 0.01-0.04 Cu; 0.02-0.05 Co; .03 maximum, As; 0.01 maximum, 0; 0.01 maximum, Zr; and with the balance of the alloy being essentially iron. The carbon content of the alloy is adjusted such that wt. % Ti/(wt. % C+wt. % N) is between 4 and 6, and most preferably about 5. In addition the sum of the wt. % P + wt. % B + wt. % S is at least 0.03 wt. %. This alloy is believed to be particularly well suited for use as fast breeder reactor fuel element cladding.

  10. Modelling of the Stress Corrosion Cracking Behaviour for Low Alloy Steels in High Temperature Water

    International Nuclear Information System (INIS)

    Tirbonod, B.

    2000-11-01

    The goal of the model is to calculate the crack growth and to determine the parameters of relevance for the stress corrosion cracking of the low alloy steels in high temperature water for reactor safety purposes. The model assumes for the crack growth mechanism an anodic dissolution initiated by the rupture of the oxide film by creep at the crack tip, a repassivation, and, for representing other possible crack growth mechanisms, a cleavage. The model for the dissolution considers all the parameters of relevance for the dissolution and well accepted laws of physics. The creep is calculated by a constitutive law of Chaboche with the finite element method. The dissolution cell is found to be situated in the region of the crack tip with a length up to a few hundred micrometers. Sensitive parameters for the crack growth are the strain to film rupture, the composition of the electrolyte, the exchange current densities, and the cleavage length. The model is in qualitative agreement with measurements. It is discussed with particular attention to the geometry and dimensions of the dissolution cell and to the species transport in the dissolution cell and along the crack. Further work should be devoted to the comparison of the model to experiments. (author)

  11. Beef cattle body temperature during climatic stress: a genome-wide association study

    Science.gov (United States)

    Howard, Jeremy T.; Kachman, Stephen D.; Snelling, Warren M.; Pollak, E. John; Ciobanu, Daniel C.; Kuehn, Larry A.; Spangler, Matthew L.

    2014-09-01

    Cattle are reared in diverse environments and collecting phenotypic body temperature (BT) measurements to characterize BT variation across diverse environments is difficult and expensive. To better understand the genetic basis of BT regulation, a genome-wide association study was conducted utilizing crossbred steers and heifers totaling 239 animals of unknown pedigree and breed fraction. During predicted extreme heat and cold stress events, hourly tympanic and vaginal BT devices were placed in steers and heifers, respectively. Individuals were genotyped with the BovineSNP50K_v2 assay and data analyzed using Bayesian models for area under the curve (AUC), a measure of BT over time, using hourly BT observations summed across 5-days (AUC summer 5-day (AUCS5D) and AUC winter 5-day (AUCW5D)). Posterior heritability estimates were moderate to high and were estimated to be 0.68 and 0.21 for AUCS5D and AUCW5D, respectively. Moderately positive correlations between direct genomic values for AUCS5D and AUCW5D (0.40) were found, although a small percentage of the top 5 % 1-Mb windows were in common. Different sets of genes were associated with BT during winter and summer, thus simultaneous selection for animals tolerant to both heat and cold appears possible.

  12. POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

    International Nuclear Information System (INIS)

    Oh, Chang H; Davis, Cliff; Hawkes, Brian D; Sherman, Steven R

    2007-01-01

    various operating conditions as well as trade offs between efficiency and capital cost. Parametric studies were carried out on reactor outlet temperature, mass flow, pressure, and turbine cooling. Recommendations on the optimal working fluid for each configuration were made. Engineering analyses were performed for several configurations of the intermediate heat transport loop that transfers heat from the nuclear reactor to the hydrogen production plant. The analyses evaluated parallel and concentric piping arrangements and two different working fluids, including helium and a liquid salt. The thermal-hydraulic analyses determined the size and insulation requirements for the hot and cold leg pipes in the different configurations. Mechanical analyses were performed to determine hoop stresses and thermal expansion characteristics for the different configurations. Economic analyses were performed to estimate the cost of the various configurations

  13. Temperature-Dependent Fatigue Strength of Diamond Coating-Substrate Interface Quantified via the Shear Failure Stress

    Science.gov (United States)

    Skordaris, G.

    2015-09-01

    A dynamic 3D-finite element method (FEM) thermomechanical model is employed for quantifying the temperature-dependent fatigue strength of nanocrystalline diamond (NCD) coating-substrate interface. This model simulates dynamically the inclined impact test on NCD-coated cemented carbide inserts considering the temperature-dependent residual stresses in the NCD coating structure. A fatigue damage of the NCD coating-substrate interface develops after a certain number of repetitive impacts depending on the applied impact load and temperature. After the interface fatigue failure, the high compressive residual stresses of the NCD coating structure are released, and the detached coating hikes up at a certain maximum height (bulge formation). The critical impact forces for avoiding the fatigue failure of the NCD coating-substrate interface, and the subsequent film detachment after 106 impacts at various temperatures were determined by conducting inclined impact tests up to 400 °C. Considering the critical impact forces, using the mentioned FEM model, the related shear failure stresses in the NCD coating-substrate interface at various temperatures were predicted.

  14. A kinematic hardening constitutive model for the uniaxial cyclic stress-strain response of magnesium sheet alloys at room temperature

    Science.gov (United States)

    He, Zhitao; Chen, Wufan; Wang, Fenghua; Feng, Miaolin

    2017-11-01

    A kinematic hardening constitutive model is presented, in which a modified form of von Mises yield function is adopted, and the initial asymmetric tension and compression yield stresses of magnesium (Mg) alloys at room temperature (RT) are considered. The hardening behavior was classified into slip, twinning, and untwinning deformation modes, and these were described by two forms of back stress to capture the mechanical response of Mg sheet alloys under cyclic loading tests at RT. Experimental values were obtained for AZ31B-O and AZ31B sheet alloys under both tension-compression-tension (T-C-T) and compression-tension (C-T) loadings to calibrate the parameters of back stresses in the proposed model. The predicted parameters of back stresses in the twinning and untwinning modes were expressed as a cubic polynomial. The predicted curves based on these parameters showed good agreement with the tests.

  15. Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

    DEFF Research Database (Denmark)

    Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas

    2008-01-01

    The conditions and timing of carbonate cementation in Cambrian sandstones of the Baltic sedimentary basin were determined by oxygen and carbon stable isotope and chemical data in combination with optical and cathodoluminescence petrographic studies. Studied samples represent a range in present....... The burial history modelling points to development of most of the dolomite cement during rapid Silurian-Devonian subsidence and Carboniferous-early Permian uplift. A wide range of precipitation temperatures indicate that temperature was not a major factor in triggering the carbonate cementation. Dolomite...... precipitation is related to early stages of organic matter maturation and thus to the oil generation history in the basin. delta C-13 values vary from +0.03% to -6.2%( PDB), suggesting limited addition of carbon from an organic source, with the major part derived from marine bicarbonate. The sourcing of carbon...

  16. U-Th Burial Dates on Ostrich Eggshell

    Science.gov (United States)

    Sharp, W. D.; Fylstra, N. D.; Tryon, C. A.; Faith, J. T.; Peppe, D. J.

    2015-12-01

    Obtaining precise and accurate dates at archaeological sites beyond the range of radiocarbon dating is challenging but essential for understanding human origins. Eggshells of ratites (large flightless birds including ostrich, emu and others) are common in many archaeological sequences in Africa, Australia and elsewhere. Ancient eggshells are geochemically suitable for the U-Th technique (1), which has about ten times the range of radiocarbon dating (>500 rather than 50 ka), making eggshells attractive dating targets. Moreover, C and N isotopic studies of eggshell provide insights into paleovegetation and paleoprecipitation central to assessing past human-environment interactions (2,3). But until now, U-Th dates on ratite eggshell have not accounted for the secondary origin of essentially all of their U. We report a novel approach to U-Th dating of eggshell that explicitly accounts for secondary U uptake that begins with burial. Using ostrich eggshell (OES) from Pleistocene-Holocene east African sites, we have measured U and 232Th concentration profiles across OES by laser ablation ICP-MS. U commonly peaks at 10s to 100s of ppb and varies 10-fold or more across the ~2 mm thickness of OES, with gradients modulated by the layered structure of the eggshell. Common Th is high near the shell surfaces, but low in the middle "pallisade" layer of OES, making it optimal for U-Th dating. We determine U-Th ages along the U concentration gradient by solution ICP-MS analyses of two or more fractions of the pallisade layer. We then estimate OES burial dates using a simple model for diffusive uptake of uranium. Comparing such "U-Th burial dates" with radiocarbon dates for OES calcite from the same shells, we find good agreement in 7 out of 9 cases, consistent with rapid burial and confirming the accuracy of the approach. The remaining 2 eggshells have anomalous patterns of apparent ages that reveal they are unsuitable for U-Th dating, thereby providing reliability criteria innate

  17. Late Sarmatian Elite Military Burial From the Southern Urals

    Directory of Open Access Journals (Sweden)

    Krivosheev Mikhail Vasilyevich

    2015-12-01

    Full Text Available The article is devoted to the burial of a warrior of Late Sarmatian time from the Southern Urals. The complex from mound no. 4 of the burial mound Taksai I is distinguished by large size of barrow and grave. The reconstructed height of the mound was less than 2 meters. The depth of the burial pit was more than 3 meters. For Late Sarmatian culture such dimensions of sepulchral structures are unique. Under the mound the ritual platform from mainland soil was discovered. The found inventory of a warrior-rider included: horse bridle, a set of bladed weapons consisting of a long sword, dagger and knife, as well as a small bronze cauldron. Analysis of inventory allows us to date this burial to the second half of the 3rd century A.D. This burial belongs to an elite funerary complexes of Late Sarmatian culture and is a burial of professional warriors. This social stratum was formed in Late Sarmatian society at the end of the 2nd - first half of the 3rd century A.D. Most of these graves are dating back to the first half of the 3rd century A.D and were found in the Low Don and in the Volga region. The situation in these regions changed in that period due to the invasion of the tribes of the North-Caucasian origin. Their occurrence is associated with the destruction of the Tanais in the Lower Don region and the spread of graves in the T-shaped catacombs in the steppe monuments. The tradition of burying warriors-horsemen of high social status almost disappears in the Volga-Don steppes after the middle of 3rd century A.D. In the Southern Urals where these processes had an indirect influence, the existence of traditional hierarchies of Late Sarmatian society could continue until the end of the 3rd century A.D. Among the parts of a horse bridle the researchers discovered bronze B-shape buckle. These buckles are widely distributed in the 4th-5th centuries A.D. in the basin of the Kama river and the Danube river. The found buckle is the earliest currently known

  18. Effect of moderate hypoxia at three acclimation temperatures on stress responses in Atlantic cod with different haemoglobin types

    DEFF Research Database (Denmark)

    Methling, Caroline; Aluru, Neelakanteswar; Vijayan, Mathilakath M

    2010-01-01

    in a difference in stress response to hypoxia exposure. Two hsp70-isoforms (labelled a and b) were detected and they differed in expression in the gills but not in the liver of Atlantic cod. Acclimation temperature significantly affected the expression of hsp70 in the liver, and in an isoform-specific manner...... in the gills. Hypoxia exposure increased the expression of hsp70 in the liver, but not the gills, of cod and this response was not influenced by the acclimation temperature. The expression of hsp70 in both tissues did not differ between fish with different haemoglobin types. Acclimation temperature...... hypoxic exposure influence the organismal and cellular stress responses in Atlantic cod. We hypothesise that HbI-2 fish are more tolerant to short-term hypoxic episodes than HbI-1 fish, and this adaptation may be independent of tissue hsp70 expression....

  19. microRNAs involved in auxin signalling modulate male sterility under high-temperature stress in cotton (Gossypium hirsutum).

    Science.gov (United States)

    Ding, Yuanhao; Ma, Yizan; Liu, Nian; Xu, Jiao; Hu, Qin; Li, Yaoyao; Wu, Yuanlong; Xie, Sai; Zhu, Longfu; Min, Ling; Zhang, Xianlong

    2017-09-01

    Male sterility caused by long-term high-temperature (HT) stress occurs widely in crops. MicroRNAs (miRNAs), a class of endogenous non-coding small RNAs, play an important role in the plant response to various abiotic stresses. To dissect the working principle of miRNAs in male sterility under HT stress in cotton, a total of 112 known miRNAs, 270 novel miRNAs and 347 target genes were identified from anthers of HT-insensitive (84021) and HT-sensitive (H05) cotton cultivars under normal-temperature and HT conditions through small RNA and degradome sequencing. Quantitative reverse transcriptase-polymerase chain reaction and 5'-RNA ligase-mediated rapid amplification of cDNA ends experiments were used to validate the sequencing data. The results show that miR156 was suppressed by HT stress in both 84021 and H05; miR160 was suppressed in 84021 but induced in H05. Correspondingly, SPLs (target genes of miR156) were induced both in 84021 and H05; ARF10 and ARF17 (target genes of miR160) were induced in 84021 but suppressed in H05. Overexpressing miR160 increased cotton sensitivity to HT stress seen as anther indehiscence, associated with the suppression of ARF10 and ARF17 expression, thereby activating the auxin response that leads to anther indehiscence. Supporting this role for auxin, exogenous Indole-3-acetic acid (IAA) leads to a stronger male sterility phenotype both in 84021 and H05 under HT stress. Cotton plants overexpressing miR157 suppressed the auxin signal, and also showed enhanced sensitivity to HT stress, with microspore abortion and anther indehiscence. Thus, we propose that the auxin signal, mediated by miRNAs, is essential for cotton anther fertility under HT stress. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  20. Habitat pollution and thermal regime modify molecular stress responses to elevated temperature in freshwater mussels (Anodonta anatina: Unionidae).

    Science.gov (United States)

    Falfushynska, H; Gnatyshyna, L; Yurchak, I; Ivanina, A; Stoliar, O; Sokolova, I

    2014-12-01

    Elevated temperature and pollution are common stressors in freshwater ecosystems. We study cellular stress response to acute warming in Anodonta anatina (Unionidae) from sites with different thermal regimes and pollution levels: a pristine area and an agriculturally polluted site with normal temperature regimes (F and A, respectively) and a polluted site with elevated temperature (N) from the cooling pond of an electrical power plant. Animals were exposed to different temperatures for 14 days and stress response markers were measured in gills, digestive gland and hemocytes. Mussels from site N and A had elevated background levels of lactate dehydrogenase activity indicating higher reliance on anaerobic metabolism for ATP production and/or redox maintenance. Exposure to 25°C and 30°C induced oxidative stress (indicated by elevated levels of lipid peroxidation products) in digestive gland and gills of mussels from A and F sites, while in mussels from N sites elevated oxidative stress was only apparent at 30°C. Temperature-induced changes in levels of antioxidants (superoxide dismutase, metallothioneins and glutathione) were tissue- and population-specific. Acute warming led to destabilization of lysosomal membranes and increased frequencies of nuclear lesions in mussels from F and A sites but not in their counterparts from N site. Elevated temperature led to an increase in the frequency of micronuclei in hemocytes in mussels from F and A sites at 25°C and 30°C and in mussels from N site at 30°C. The mussels from N site also demonstrated better survival at elevated temperature (30°C) than their counterparts from the F and A sites. Taken together, these data indicate that long-term acclimation and/or adaptation of A. anatina to elevated temperatures result in increased thermotolerance and alleviate stress response to moderate temperature rise. In contrast, extreme warming (30°C) is harmful to mussels from all populations indicating limit to this induced

  1. Analysis of transient thermal stresses in an orthotropic finite rectangular plate exhibiting temperature-dependent material properties by finite difference method

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro

    1983-01-01

    Recently, the analysis of thermal stress problem taking the temperature dependence of material constants into account has been regarded as an important subject since the various industrial problems concerning thermal stress occur at relatively large temperature gradient. Only the analysis of one-dimensional thermal stress has been made so far, taking the temperature dependence of material constants into account. In this study, in order to examine the effect of the temperature dependence of material constants on the thermal stress arising in a two-dimensional temperature field, the thermal stress problem of an orthotropic rectangular plate was formulated by using stress functions, taking the temperature dependence of thermal conductivity, specific heat, density, Young's modulus, coefficient of linear expansion and Poisson's ratio in consideration. The effects of the temperature dependence of material constants on temperature distribution and thermal stress distribution were examined by carrying out the numerical analysis by difference method. The numerical analysis was carried out for an isotropic rectangular plate of low carbon steel, of which the data on the temperature dependence of material constants are available. The temperature drop of 8 deg C at maximum as compared with the case of constant material properties was obtained. (Kako, I.)

  2. Numerical simulation of the influence factors for rotary kiln in temperature field and stress field and the structure optimization

    Directory of Open Access Journals (Sweden)

    Gongfa Li

    2015-06-01

    Full Text Available With the development of metallurgical industry and the improvement of kiln technology, the processing properties of kiln equipment are being paid more attention. The rotary kiln is one of the most representatives of the furnace equipment; higher requirements of the rotary kiln are put forward in response to the call of the national energy saving and emission reduction. That is, the new designed equipment has the characteristics of the optimal energy consumption and stable performance. In order to analyze the energy consumption of the rotary kiln, it is necessary to study the heat transfer process of the rotary kilns. The three-dimensional numerical model of the rotary kiln is set up by using the finite element technology. After analyzing the data, it is found that different thicknesses of the kiln crust and different working conditions have certain influence on the rotary kiln’s temperature field and stress field. After analyzing the result of the simulation, the temperature of the rotary kiln’s outer wall has an approximate linear relationship with the thickness of the kiln crust. Changing the thickness of the kiln crust will not only alter the value of the maximum stress but also have influence on the position of maximum stress. The increase in the thickness of the kiln crust can reduce the extreme value of stress. When the wind speed of induce fan inside the kiln is larger, the temperature of each layer will be relatively high as well, and the temperature curve is softer, and the temperature variation is more stable. It has also been found that when the comprehensive coefficient of heat exchange outside the kiln surface is larger, the thermal stress created by the body of kiln is smaller. The phenomenon of excessive thermal stress can be improved by changing the outer surface ventilation conditions of the rotary kiln. In order to ensure that the high temperature of the kiln wall has no influence on working wheels, and make sure the

  3. 24-Epibrassinoslide enhances plant tolerance to stress from low temperatures and poor light intensities in tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Cui, Lirong; Zou, Zhirong; Zhang, Jing; Zhao, Yanyan; Yan, Fei

    2016-01-01

    Brassinosteroids (Brs) are a newly recognized group of active steroidal hormones that occur at low concentrations in all plant parts and one of the active and stable forms is 24-epibrassinolide (EBR). We investigated the effect of EBR on tomato (Lycopersicon esculentum Mill.) and its mechanism when seedlings were exposed to low temperature and poor light stress conditions. Leaves of stress-tolerant 'Zhongza9' and stress-sensitive 'Zhongshu4' cultivars were pre-treated with spray solutions containing either 0.1 μM EBR or no EBR (control). The plants were then transferred to chambers where they were exposed to low temperatures of 12 °C/6 °C (day/night) under a low light (LL) level of 80 μmol · m(-2) · s(-1). Exogenous application of EBR significantly increased the antioxidant activity of superoxide dismutase, catalase and peroxidase, and decreased the rate of O2 · (-) formation and H2O2 and malondialdehyde contents. Additionally, the ATP synthase β subunit content was increased by exogenous hormone application. Based on these results, we conclude that exogenous EBR can elicit synergism between the antioxidant enzyme systems and the ATP synthase β subunit so that scavenging of reactive oxygen species becomes more efficient. These activities enable plants to cope better under combined low temperature and poor light stresses.

  4. Modelling and simulation of temperature and concentration dispersion in a couple stress nanofluid flow through stenotic tapered arteries

    Science.gov (United States)

    Ramana Reddy, J. V.; Srikanth, D.; Das, Samir K.

    2017-08-01

    A couple stress fluid model with the suspension of silver nanoparticles is proposed in order to investigate theoretically the natural convection of temperature and concentration. In particular, the flow is considered in an artery with an obstruction wherein the rheology of blood is taken as a couple stress fluid. The effects of the permeability of the stenosis and the treatment procedure involving a catheter are also considered in the model. The obtained non-linear momentum, temperature and concentration equations are solved using the homotopy perturbation method. Nanoparticles and the two viscosities of the couple stress fluid seem to play a significant role in the flow regime. The pressure drop, flow rate, resistance to the fluid flow and shear stress are computed and their effects are analyzed with respect to various fluids and geometric parameters. Convergence of the temperature and its dependency on the degree of deformation is effectively depicted. It is observed that the Nusselt number increases as the volume fraction increases. Hence magnification of molecular thermal dispersion can be achieved by increasing the nanoparticle concentration. It is also observed that concentration dispersion is greater for severe stenosis and it is maximum at the first extrema. The secondary flow of the axial velocity in the stenotic region is observed and is asymmetric in the tapered artery. The obtained results can be utilized in understanding the increase in heat transfer and enhancement of mass dispersion, which could be used for drug delivery in the treatment of stenotic conditions.

  5. Effects of different rearing temperatures on muscle development and stress response in the early larval stages of Acipenser baerii

    Directory of Open Access Journals (Sweden)

    Lucia Aidos

    2017-11-01

    Full Text Available The present study aims at investigating muscle development and stress response in early stages of Siberian sturgeon when subjected to different rearing temperatures, by analysing growth and development of the muscle and by assessing the stress response of yolk-sac larvae. Siberian sturgeon larvae were reared at 16°C, 19°C and 22°C until the yolk-sac was completely absorbed. Sampling timepoints were: hatching, schooling and complete yolk-sac absorption stage. Histometrical, histochemical and immunohistochemical analyses were performed in order to characterize muscle growth (total muscle area, TMA; slow muscle area, SMA; fast muscle area, FMA, development (anti-proliferating cell nuclear antigen -PCNA or anticaspase as well as stress conditions by specific stress biomarkers (heat shock protein 70 or 90, HSP70 or HSP90. Larvae subjected to the highest water temperature showed a faster yolk-sac absorption. Histometry revealed that both TMA and FMA were larger in the schooling stage at 19°C while no differences were observed in the SMA at any of the tested rearing temperatures. PCNA quantification revealed a significantly higher number of proliferating cells in the yolk-sac absorption phase at 22°C than at 16°C. HSP90 immunopositivity seems to be particularly evident at 19°C. HPS70 immunopositivity was never observed in the developing lateral muscle.

  6. Shallow ground burial of low-level waste

    International Nuclear Information System (INIS)

    Camilleri, A.; Cooper, M.B.; Hargrave, N.J.; Munslow-Davies, L.

    1989-01-01

    Acceptance criteria for the disposal of low-level radioactive wastes are presented for adoption throughout Australia, a continent in which there are readily available areas in arid, sparsely inhabited places, likely to be suitable as sites for shallow ground burial. Drawing upon overseas practices and experiences, criteria have been developed for low-level waste disposal and are intended to be applicable and relevant to the Australian situation. Concentration levels have been derived for a shallow ground burial facility assuming a realistic institutional control period of 200 years. A comparison is made between this period and institutional control for 100 years and 300 years. Longer institutional control periods enable the acceptance of higher concentrations of radionuclides of intermediate half-lives. Scenarios, which have been considered, include current Australian pastoral practices and traditional Aboriginal occupancy. The derived radionuclide concentration levels for the disposal of low level wastes are not dissimilar to those developed in other countries. 17 refs., 6 tabs., 1 fig

  7. Salt stress and temperatures on the germination and initial growth of ‘jurema-de-embira’ (Mimosa ophthalmocentra seedlings

    Directory of Open Access Journals (Sweden)

    Narjara W. Nogueira

    Full Text Available ABSTRACT The objective of this study was to evaluate the effects of salinity on the germination and initial growth of ‘jurema-de-embira’ (Mimosa ophthalmocentra seedlings at different temperatures. The experiment was installed in a completely randomized design, in a factorial scheme of eight salt concentrations (0; 4.0; 8.0; 12.0; 16.0; 20.0; 24.0 and 28.0 dS m-1 and four temperatures (25, 30, 35 and 20-30 °C in four replicates of 25 seeds under an 8-h photoperiod in Biochemical Oxygen Demand germinators. The variables analyzed were: germination, germination speed index, shoot and root lengths, and shoot, root and total dry matter. Temperature variation influences the response of ‘jurema-de-embira’ seeds to salinity, and the salt stress is intensified by the increase in temperature. ‘Jurema-de-embira’ is tolerant to salt stress in the germination stage, showing satisfactory germination up to the salinity level 20 dS m-1, at temperatures below 30 °C. The initial growth of ‘jurema-de-embira’ plants is satisfactory up to salinity of 12 dS m-1, at temperatures below 30 °C.

  8. Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress tolerant crops

    Directory of Open Access Journals (Sweden)

    Craita eBita

    2013-07-01

    Full Text Available Global warming is predicted to have a general negative effect on plant growth due to the negative effect of high temperatures on plant development. The increasing threat of climatological extremes, including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review we assess the impact of global climate change on the production of agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that have will be likely to show the most extreme reductions in yield as a result of warming in general and the expected fluctuations in temperature. High temperature stress has a wide range of effects on plants both in terms of physiology, biochemistry and gene regulation pathways. In this review we present the recent advances of research on all these level of investigation focusing on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally we review possible mechanisms and methods which can lead to the generation of new varieties that will allow sustainable yield production in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations.

  9. Stress-relieving annealing of Cr-Mo steel for high temperature pressure vessels and the quality change in use

    International Nuclear Information System (INIS)

    Makioka, Minoru; Hirano, Hiromichi

    1976-01-01

    The securing of good mechanical properties is difficult in thick plates for large pressure vessels because cooling rate is insufficient and time is prolonged in heat treatment. Cr-Mo steel plates are usually used in the state of improved notch toughness though somewhat reduced strength by normalizing or accelerated cooling and tempering. If the time for heat treatment is prolonged, the embrittlement occurs. The effects of temperature, holding time, and cooling rate in stress-relieving treatment on the mechanical properties of 1-1/4Cr - 1/2Mo, 2-1/4Cr - 1Mo, 3Cr - 1Mo, and 5Cr - 1/2Mo steels were investigated. The tensile strength lowered almost linearly as the hollomon-Jaffe parameter of heat treatment condition increased in all the steels. The transition temperature shifted continuously to high temperature side in 1-1/4Cr - 1/2Mo steel, but the notch toughness was improved up to certain values and then the tendency turning to brittleness was shown in the other steels, as the H-J parameter increased. When the holding time became longer, the transition temperature shifted to higher temperature side, but the cooling rate showed no effect. The condition for stress relieving treatment must be selected so that the ferrite bands observed in welded metal do not arise. The embrittlement at the operation temperature of 400 - 450 0 C for a long time is evaluated by the comparison with that by stepped cooling method. (Kako, I.)

  10. Multiple heat priming enhances thermo-tolerance to a later high temperature stress via improving subcellular antioxidant activities in wheat seedlings

    DEFF Research Database (Denmark)

    Wang, Xiao; Cai, Jian; Liu, Fulai

    2014-01-01

    Seedlings of winter wheat (Triticum aestivum L.) were firstly twice heat-primed at 32/24 °C, and subsequently subjected to a more severe high temperature stress at 35/27 °C. The later high temperature stress significantly decreased plant biomass and leaf total soluble sugars concentration. Howeve...

  11. Development of waste unit for use in shallow land burial

    International Nuclear Information System (INIS)

    Brodersen, K.

    1986-01-01

    A hexagonal waste unit has been developed for use in shallow land burial of low- and medium-level radioactive waste. The waste units used as overpack on empty standard 210 1 drums have been tested for tightness and mechanical resistance. Experimental burial of 21 empty full-size units has demonstrated the emplacement of the containers and the sealing of the crevises between them with molten bitumen. The development of the experimental burial with time is being followed. Three different conceptual designs for advanced burial systems using the hexagonal standard units are described. The outer barrier is a thick concrete structure covered by 2, 10 or 20 m soil, respectively. The waste units were cast from a normal high-quality concrete as well as from Densit, a new, very strong and impermeable type of concrete prepared by the combined use of silica-fume (microsilica) and a superplastizicer as additives. The migration of Cl - , Cs + and tritiated water was found to be much slower in Densit than in normal concrete. In combination with leaching measurements for Cs + from the same materials the results are used to present some theoretical considerations concerning transport through solution-filled pore systems as dependent on pore-size distribution, tortuosity, etc. A method based on neutron-activated cement cast in form of thin plates has been developed and used to study the dissolution chemistry of concrete. A preliminary model is presented. Indications for precipitation mechanisms were obtained. Densit was demonstrated to ensure a high degree of corrosion protection for steel reinforcement. The reason is mainly the high electrical resistivity combined with low diffusive transport in the material. The pozzolanic reaction results in somewhat lower pH in the pore water than in normal concrete, but the effect is not so pronounced that the passivation of steel reinforcement is endangered

  12. Touchstones from early medieval burials in Tuna in Alsike, Sweden

    Czech Academy of Sciences Publication Activity Database

    Ježek, Martin

    2014-01-01

    Roč. 42, February (2014), s. 422-429 ISSN 0305-4403 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M300021203 Institutional support: RVO:67985912 Keywords : Early Middle Ages * Viking Age * elite * boat burial * touchstone * precious metal * zinc * nickel Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 2.196, year: 2014

  13. Does Temperature and UV Exposure History Modulate the Effects of Temperature and UV Stress on Symbiodinium Growth Rates?

    Science.gov (United States)

    Temperature and ultraviolet radiation (UV) alone or in combination are known to inhibit the growth of Symbiodinium isolates. This conclusion was drawn from a number of studies having widely different exposure scenarios. Here we have examined the effects of pre-exposure acclimat...

  14. Effects of carbon ion irradiation on survival rate, catalase and peroxidase activity of alfalfa M1 under low temperature stress

    International Nuclear Information System (INIS)

    Wang Shuyang; Li Jinghua; Jiang Boling

    2014-01-01

    In this study, three kinds of alfalfa including Zhonglan 1, BC-04-477 and Ta Cheng were treated with different doses of 12 C 6+ (75 keV) heavy ion radiation, and then the influence of survival rate, catalase (CAT) and peroxidase (POD) activity of M1 with low temperature stress were tested. The results showed that under the condition of 400 Gy radiation dose, the survival rate and CAT activity of Zhonglan 1 under low temperature stress have increased by 33.3%, 56.3% respectively compared with those of the control group, while there was no difference in POD activity between those two groups. The survival rate, CAT and POD activity of BC-04-477 treated with low temperature have been improved by 33.3%, 69.2%, 5.1% respectively compared with those of the control group when the radiation dose was 400 Gy. Compared with those of the control group, the survival rate, CAT and POD activity of Ta Cheng under low temperature stress have been improved by 25%, 26%,22.8% respectively when the radiation dose was 800 Gy. These results indicate that the viability and the cold resistance ability of Zhong Lan 1, BC-04-477 and Ta Cheng can be improved by 12 C 6+ radiation. (authors)

  15. Biaxial stress driven tetragonal symmetry breaking and high-temperature ferromagnetic semiconductor from half-metallic CrO2

    Science.gov (United States)

    Xiao, Xiang-Bo; Liu, Bang-Gui

    2018-03-01

    It is highly desirable to combine the full spin polarization of carriers with modern semiconductor technology for spintronic applications. For this purpose, one needs good crystalline ferromagnetic (or ferrimagnetic) semiconductors with high Curie temperatures. Rutile CrO2 is a half-metallic spintronic material with Curie temperature 394 K and can have nearly full spin polarization at room temperature. Here, we find through first-principles investigation that when a biaxial compressive stress is applied on rutile CrO2, the density of states at the Fermi level decreases with the in-plane compressive strain, there is a structural phase transition to an orthorhombic phase at the strain of -5.6 % , and then appears an electronic phase transition to a semiconductor phase at -6.1 % . Further analysis shows that this structural transition, accompanying the tetragonal symmetry breaking, is induced by the stress-driven distortion and rotation of the oxygen octahedron of Cr, and the half-metal-semiconductor transition originates from the enhancement of the crystal field splitting due to the structural change. Importantly, our systematic total-energy comparison indicates the ferromagnetic Curie temperature remains almost independent of the strain, near 400 K. This biaxial stress can be realized by applying biaxial pressure or growing the CrO2 epitaxially on appropriate substrates. These results should be useful for realizing full (100%) spin polarization of controllable carriers as one uses in modern semiconductor technology.

  16. Modelling the evolution of composition-and stress-depth profiles in austenitic stainless steels during low-temperature nitriding

    DEFF Research Database (Denmark)

    Jespersen, Freja Nygaard; Hattel, Jesper Henri; Somers, Marcel A. J.

    2016-01-01

    that accompanies the dissolution of high nitrogen contents in expanded austenite. An intriguing phenomenon during low-temperature nitriding is that the residual stresses evoked by dissolution of nitrogen in the solid state, affect the thermodynamics and the diffusion kinetics of nitrogen dissolution....... In the present paper solid mechanics was combined with thermodynamics and diffusion kinetics to simulate the evolution of composition-depth and stress-depth profiles resulting from nitriding. The model takes into account a composition-dependent diffusion coefficient of nitrogen in expanded austenite, short range...

  17. Self-burial mechanics of hygroscopically responsive awns.

    Science.gov (United States)

    Jung, Wonjong; Kim, Wonjung; Kim, Ho-Young

    2014-12-01

    We present the results of a combined experimental and theoretical investigation of the mechanics of self-burial of some plant seeds whose morphologies respond to environmental changes in humidity. The seeds of Erodium and Pelargonium have hygroscopically responsive awns that play a critical role in their self-burial into soil. The awn, coiled in a dry state, uncoils to stretch linearly under highly humid condition because of a tilted arrangement of cellulose microfibrils in one of the layers of the awn's bilayered structure. By measuring the mechanical characteristics of the awns of Pelargonium carnosum, we find that the extensional force of the awn can be aptly modeled by the theory of elasticity for a coiled spring. We further show that although the resistance to the seed-head penetrating relatively coarse soils without spinning is large enough to block the digging seed, the rotation of the seed greatly reduces the soil's resistance down to a level the awn can easily overcome. Our mechanical analysis reveals that the self-burial of the seed is a sophisticated outcome of the helically coiled configuration of the awn. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  18. Examination of representative drum from 618-9 Burial Ground

    International Nuclear Information System (INIS)

    Duncan, D.R.; Bunnell, L.R.

    1992-10-01

    The work described in this report was conducted in pursuance of Task E of the Pacific Northwest Laboratory Solid Waste Technology Support Program for Westinghouse Hanford Company. Task E calls for a determination of the corrosion rate of low-carbon steels under typical Hanford Site conditions. To meet this objective, Pacific Northwest Laboratory examined one intact drum that was judged to be representative of the largely intact drums excavated at the 618-9 Burial Ground located west of the 300 Area at the Hanford Site. Six samples were examined to characterize the drum, its composition, and its corrosion and corrosion products. The drum, which was found empty, was constructed of low-carbon steel. Its surface appeared relatively sound. The drum metal varied in thickness, but the minimum thickness in the samples was near 0.020 in. The corrosion corresponds to approximately 25 to 35 mils of metal loss, roughly a 1 mil/yr corrosion rate. Corrosion products were goethite and maghymite, expected products of iron buried in soil. Apparently, the drum leaked some time ago, but the cause of the leakage is unknown because records of the drums and their burial are limited. The drum was empty when found, and it is possible that it could have failed by pitting rather than by general corrosion. A pitting rate of about 3.5 mils/yr would have caused loss of drum integrity in the time since burial

  19. Ground resistance influences lizard burial in dry and wet sand

    Science.gov (United States)

    Sharpe, Sarah; Kuckuk, Robyn; Goldman, Daniel

    2012-11-01

    Many terrestrial animals move within soil in which water content can vary, and little is known about how water content affects locomotor performance. To investigate the effect of water content on burial, we created controlled dry and wet substrates. We used 0.3 mm glass particles and varied water content W, the mass of water to mass of dry loosely packed sand. Drag force on a submerged 1.6 cm diameter rod increased by a factor of 4 as W increased from 0 to 0.03, after which force increases were small. Drag force in wet media periodically fluctuated with time and corresponded with surface fracturing. We characterized how W affected burial performance and strategy of a generalist burrower, the ocellated skink lizard (Chalcides ocellatus). High speed x-ray imaging was used to measure head, body and limb kinematics in substrates with W= 0 and W= 0.03. In both states during burial the body was maintained in a curved posture and the animal moved using a start-stop motion. During movement, the head oscillated and the forelimb on the convex side of the body was used to push the animal forward. Both speed and angular excursion of the head oscillation decreased in the W= 0.03 state. The differences in locomotion were attributed to the changing resistance force within the media.

  20. Thallium-isotopic compositions of euxinic sediments as a proxy for global manganese-oxide burial

    Science.gov (United States)

    Owens, Jeremy D.; Nielsen, Sune G.; Horner, Tristan J.; Ostrander, Chadlin M.; Peterson, Larry C.

    2017-09-01

    Thallium (Tl) isotopes are a new and potentially powerful paleoredox proxy that may track bottom water oxygen conditions based on the global burial flux of manganese oxides. Thallium has a residence time of ∼20 thousand years, which is longer than the ocean mixing time, and it has been inferred that modern oxic seawater is conservative with respect to both concentration and isotopes. Marine sources of Tl have nearly identical isotopic values. Therefore, the Tl sinks, adsorption onto manganese oxides and low temperature oceanic crust alteration (the dominant seawater output), are the primary controls of the seawater isotopic composition. For relatively short-term, ∼million years, redox events it is reasonable to assume that the dominant mechanism that alters the Tl isotopic composition of seawater is associated with manganese oxide burial because large variability in low temperature ocean crust alteration is controlled by long-term, multi-million years, average ocean crust production rates. This study presents new Tl isotope data for an open ocean transect in the South Atlantic, and depth transects for two euxinic basins (anoxic and free sulfide in the water column), the Cariaco Basin and Black Sea. The Tl isotopic signature of open ocean seawater in the South Atlantic was found to be homogeneous with ε205Tl = -6.0 ± 0.3 (±2 SD, n = 41) while oxic waters from Cariaco and the Black Sea are -5.6 and -2.2, respectively. Combined with existing data from the Pacific and Arctic Oceans, our Atlantic data establish the conservatism of Tl isotopes in the global ocean. In contrast, partially- and predominantly-restricted basins reveal Tl isotope differences that vary between open-ocean (-6) and continental material (-2) ε205Tl, scaling with the degree of restriction. Regardless of the differences between basins, Tl is quantitatively removed from their euxinic waters below the chemocline. The burial of Tl in euxinic sediments is estimated to be an order of magnitude

  1. Acute and chronic temperature stress on copepod individuals and populations. Final report, November 1977-February 1983

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, B.P.

    1983-10-01

    Temperature variation resulting from thermal discharges of two power plants affected temperature tolerances and densities of two copepod species, Eurytemora affinis and Acartia tonsa. Temperature tolerances were increased genetically (next generation) provided either ambient temperature or delta T was sufficiently high. Densities also varied with temperature but not always systematically. Other criteria used to assess the environmental influence of power plant were egg production and potentials for physiological and genetic adaptation.

  2. A phenomenological formulation for the shape/temperature memory effect in amorphous polymers with multi-stress components

    Science.gov (United States)

    Lu, Haibao; Wang, Xiaodong; Yu, Kai; Huang, Wei Min; Yao, Yongtao; Leng, Jinsong

    2017-09-01

    By means of combining the influence of temperature and strain rate, and based on the cooperative Eyring model, a phenomenological formulation for the shape memory effect and temperature memory effect of an amorphous shape memory polymer (SMP) is proposed. The internal stress and stored mechanical energy are correlated to shape/temperature memory behaviours below and above the glass transition temperature. The working mechanism and fundamentals for the chemo-responsive shape memory behaviour in SMPs are further investigated in terms of the activation enthalpy parameter for inductive depression. Simulation using the proposed model is compared with the experimental results reported in the literature. Predictions are also made using the proposed model. This phenomenological framework is expected to provide a powerful tool for investigating the underlying thermomechanics that originate in the movement of cooperative segments and segmental relaxations in SMPs.

  3. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    International Nuclear Information System (INIS)

    Freiesleben, Trine; Sohbati, Reza; Murray, Andrew; Jain, Mayank; Al Khasawneh, Sahar; Hvidt, Søren; Jakobsen, Bo

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescence–depth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated luminescence-depth profile from a feldspar-rich granite cobble from an archaeological site near Aarhus, Denmark. This profile shows qualitative evidence for multiple daylight exposure and burial events; these are quantified using the model developed here. By determining the burial ages from the surface layer of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible to determine the length of a fossil exposure, using a known natural light exposure as calibration. - Highlights: • Evidence for multiple exposure and burial events in the history of a single cobble. • OSL rock surface dating model improved to include multiple burial/exposure cycles. • Application of the new model quantifies burial and exposure events.

  4. Residual Stress Formation Relating to Peak Temperature- and Austenite Grain Size-based Phase Transformation of S355 Steel

    Science.gov (United States)

    Klaproth, Fabian; Vollertsen, Frank

    Nowadays thermal forming processes of steel are state of the art in industrial applications. Nevertheless, the influences of thermal induced phase-transformation on residual stresses and strength have not been fully observed. Times needed for transformation are affected by the initial austenite grain size, while the prevailing peak temperature influences austenite grain growth. Higher temperatures lead to larger austenite grains, leading to increased times for transformation. In order to get an embraced understanding of such effects numerical simulations of phase-transformations are mandatory. In this paper simulations of thermal forming processes, using S355 steel, are presented. Different continuous-cooling-transformation-diagrams (cct-diagrams) of specific austenite grain sizes for temperatures between transformation point AC3 and melting temperature are implemented in the model. It is shown that resulting magnitudes of residual stresses vary between 248 N/mm2 and 550 N/mm2. Finally an approach for the impact on relevant peak temperatures in the heat affected zone is outlined.

  5. USE OF AUTODESK SIMULATION MULTIPHYSICS FOR RESEARCH OF TEMPERATURE FIELDS, STRESS AND DEFOMATION IN THE CONSTRUCTION OF GEAR PUMP

    Directory of Open Access Journals (Sweden)

    A. V. Puzanov

    2016-01-01

    Full Text Available Gear pumps are the most common type of hydraulic machines. They are used in various industries: oil and gas processing industry, in machine tools, mobile military, road-building and agricultural machinery. The need to ensure efficiency of hydraulic mobile applications in a wide climatic range requires increasing the accuracy of the calculation methods for the design of their elements. The results of temperature field modeling and caused them stress and strain. The results obtained allowed to justify the design and technological solutions, providing an increase of hydraulic performance at critical ambient temperatures.

  6. High Temperature Stress Analysis on 61-pin Test Assembly for Reactor Core Sub-channel Flow Test

    International Nuclear Information System (INIS)

    Lee, Dongwon; Kim, Hyungmo; Lee, Hyeongyeon

    2014-01-01

    In this study, a high temperature heat transfer and stress analysis of a 61-pin test fuel assembly scaled down from the full scale 217-pin sub-assembly was conducted. The reactor core subchannel flow characteristic test will be conducted to evaluate uncertainties in computer codes used for reactor core thermal hydraulic design. Stress analysis for a 61-pin fuel assembly scaled down from Prototype Generation IV Sodium-cooled Fast Reactor was conducted and structural integrity in terms of load controlled stress limits was conducted. In this study, The evaluations on load-controlled stress limits for a 61-pin test fuel assembly to be used for reactor core subchannel flow distribution tests were conducted assuming that the test assembly is installed in a Prototype Generation IV Sodium-cooled fast reactor core. The 61-pin test assembly has the geometric similarity on P/D and H/D with PGSFR and material of fuel assembly is austenitic stainless steel 316L. The stress analysis results showed that 4.05MPa under primary load occurred at mid part of the test assembly and it was shown that the value of 4.05Mpa was far smaller than the code allowable of 127MPa. , it was shown that the stress intensity due to due to primary load is very small. The stress analysis results under primary and secondary loads showed that maximum stress intensity of 84.08MPa occurred at upper flange tangent to outer casing and the value was well within the code allowable of 268.8MPa. Integrity evaluations based on strain limits and creep-fatigue damage are underway according to the elevated design codes

  7. Stress corrosion cracking of stainless steel under deaerated high-temperature water. Influence of cold work and processing orientation

    International Nuclear Information System (INIS)

    Terachi, Takumi; Yamada, Takuyo; Chiba, Goro; Arioka, Koji

    2006-01-01

    The influence of cold work and processing orientation on the propagation of stress corrosion cracking (SCC) of stainless steel under hydrogenated high-temperature water was examined. It was shown that (1) the crack growth rates increased with heaviness of cold work, and (2) processing orientation affected crack growth rate with cracking direction. Crack growth rates showed anisotropy of T-L>>T-S>L-S, with T-S and L-S branches representing high shear stress direction. Geometric deformation of crystal grains due to cold work caused the anisotropy and shear stress also assisted the SCC propagation. (3) The step intervals of slip like patterns observed on intergranular facets increased cold work. (4) Nano-indentation hardness of the crack tip together with EBSD measurement indicated that the change of hardness due to crack propagation was less than 5% cold-work, even though the distance from the crack tip was 10μm. (author)

  8. Temperature stress differentially modulates transcription in meiotic anthers of heat-tolerant and heat-sensitive tomato plants

    Directory of Open Access Journals (Sweden)

    Pezzotti Mario

    2011-07-01

    Full Text Available Abstract Background Fluctuations in temperature occur naturally during plant growth and reproduction. However, in the hot summers this variation may become stressful and damaging for the molecular mechanisms involved in proper cell growth, impairing thus plant development and particularly fruit-set in many crop plants. Tolerance to such a stress can be achieved by constitutive gene expression or by rapid changes in gene expression, which ultimately leads to protection against thermal damage. We have used cDNA-AFLP and microarray analyses to compare the early response of the tomato meiotic anther transcriptome to moderate heat stress conditions (32°C in a heat-tolerant and a heat-sensitive tomato genotype. In the light of the expected global temperature increases, elucidating such protective mechanisms and identifying candidate tolerance genes can be used to improve breeding strategies for crop tolerance to heat stress. Results The cDNA-AFLP analysis shows that 30 h of moderate heat stress (MHS alter the expression of approximately 1% of the studied transcript-derived fragments in a heat-sensitive genotype. The major effect is gene down-regulation after the first 2 h of stress. The microarray analysis subsequently applied to elucidate early responses of a heat-tolerant and a heat-sensitive tomato genotype, also shows about 1% of the genes having significant changes in expression after the 2 h of stress. The tolerant genotype not only reacts with moderate transcriptomic changes but also exhibits constitutively higher expression levels of genes involved in protection and thermotolerance. Conclusion In contrast to the heat-sensitive genotype, the heat-tolerant genotype exhibits moderate transcriptional changes under moderate heat stress. Moreover, the heat-tolerant genotype also shows a different constitutive gene expression profile compared to the heat-sensitive genotype, indicating genetic differences in adaptation to increased temperatures. In

  9. Recovery stress and shape memory stability in Ni-Ti-Cu thin wires at high temperatures

    Czech Academy of Sciences Publication Activity Database

    Molnár, Peter; Van Humbeeck, J.

    2011-01-01

    Roč. 102, č. 11 (2011), s. 1362-1368 ISSN 1862-5282 Institutional research plan: CEZ:AV0Z10100520 Keywords : shape memory alloys * recovery stress * Ni-Ti-Cu * stress relaxation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.830, year: 2011 http://www.ijmr.de/directlink.asp?MK110596

  10. Structural modification of aluminium oxynitride phases under stresses at high temperatures, high pressures and under irradiation by fast neutrons

    International Nuclear Information System (INIS)

    Labbe, J.C.; Jeanne, A.; Roult, G.

    1990-01-01

    The structural modifications of the aluminium oxynitride phases under stresses are studied by the time of flight neutron diffraction method, at high temperatures (up to 1375degC), at high pressures (up to 2.4 GPa), and under irradiation by fast neutrons (up to 3.2 X 10 20 n/cm 2 ). In each case the evolutions of cell parameter, interatomic bond angles, bond lengths and atomic positions are given. (orig.)

  11. Numerical simulation of temperature field and thermal stress field in the new type of ladle with the nanometer adiabatic material

    Directory of Open Access Journals (Sweden)

    Gongfa Li

    2015-04-01

    Full Text Available With the development of metallurgical industry and the improvement of continuous casting technology, the processing properties of casting technology equipment are being paid more attention. Ladle is one of the most representatives of the furnace equipment; higher requirements of ladle are put forward in response to the call for national energy-saving and emission reduction. According to the requirements of actual operator and working condition, a lining structure of a new type of ladle with nanometer adiabatic material is put forward. Based on heat transfer theory and finite element technology, the three-dimensional finite element model of a new type of ladle is established. Temperature field and stress field of the new type of ladle with the nanometer adiabatic material in lining structure after baking are analyzed. The results indicate that the distributions of temperature and thermal stress level of working layer, permanent layer, and nanometer heat insulating layer are similar, and they are in the permissible stress and temperature range of each material for the new type of ladle. Especially heat preservation effect of nanometer adiabatic material is excellent. Furthermore, the maximum temperature of shell for the new type of ladle drops to 114°C than the traditional ladle, and the maximum stress of shell for the new type of ladle is lower than the traditional ladle, that is, 114 MPa. It can provide reliable theory for energy-saving and emission reduction of metallurgy industry, which also points out the right direction for the future development of the iron and steel industry.

  12. Influence of solute, pH, and incubation temperature on recovery of heat-stressed Wallemia sebi conidia.

    Science.gov (United States)

    Beuchat, L R; Pitt, J I

    1990-08-01

    The influences of glucose, sorbitol, and NaCl in a basal enumeration medium at water activities (aw) from 0.82 to 0.97 on colony formation by sublethally heat-stressed Wallemia sebi conidia were determined. Over this aw range, glucose and sorbitol had similar effects on recovery, whereas at an aw of 0.82 to 0.92, NaCl had a detrimental effect. Colony diameters were generally largest on media containing sorbitol and smallest on media containing NaCl. Maximum colony size and viable population of heat-stressed conidia were observed on media at an aw of ca. 0.92. When the recovery incubation temperature was 20 degrees C, the number of uninjured conidia detected at an aw of 0.82 was reduced compared with the number detected at 25 degrees C, while at 30 degrees C, the number recovered at an aw of 0.97 was reduced. The effect on heat-stressed conidia was magnified. This suggests that W. sebi conidia may be more tolerant of aw values higher than the optimum 0.92 when the incubation temperature is decreased from the near optimum of 25 degrees C and less tolerant of aw values greater than 0.92 when the incubation temperature is higher than 25 degrees C. The sensitivity of heat-stressed conidia increased as the pH of the recovery medium was decreased from 6.55 to 3.71. W. sebi conidia dispersed in wheat flour at aw values of 0.43 and 0.71 and stored for up to 65 days at both 1 and 25 degrees C neither lost viability nor underwent sublethal desiccation or temperature injury.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth

    Directory of Open Access Journals (Sweden)

    JUAN eMORAL

    2015-06-01

    Full Text Available Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt and the type of water stress (matric or osmotic on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30ºC during both periods, with a maximum around 20ºC. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche spp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  14. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth.

    Science.gov (United States)

    Moral, Juan; Lozano-Baena, María Dolores; Rubiales, Diego

    2015-01-01

    Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt) and the type of water stress (matric or osmotic) on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30°C during both periods, with a maximum around 20°C. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche sp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  15. Transcriptome-based discovery of AP2/ERF transcription factors related to temperature stress in tea plant (Camellia sinensis).

    Science.gov (United States)

    Wu, Zhi-Jun; Li, Xing-Hui; Liu, Zhi-Wei; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2015-11-01

    Tea plant (Camellia sinensis) is an important natural resource for the global supply of non-alcoholic beverage production. The extension of tea plant cultivation is challenged by biotic and abiotic stresses. Transcription factors (TFs) of the APETALA 2 (AP2)/ethylene-responsive factor (ERF) family are involved in growth and anti-stresses through multifaceted transcriptional regulation in plants. This study comprehensively analyzed AP2/ERF family TFs from C. sinensis on the basis of the transcriptome sequencing data of four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. A total of 89 putative AP2/ERF transcription factors with full-length AP2 domain were identified from C. sinensis and classified into five subfamilies, namely, AP2, dehydration-responsive-element-binding (DREB), ERF, related to ABI3/VP (RAV), and Soloist. All identified CsAP2/ERF genes presented relatively stable expression levels in the four tea plant cultivars. Many groups also showed cultivar specificity. Five CsAP2/ERF genes from each AP2/ERF subfamily (DREB, ERF, AP2, and RAV) were related to temperature stresses; these results indicated that AP2/ERF TFs may play important roles in abnormal temperature stress response in C. sinensis.

  16. The Interaction Effect of Salicylic Acid and High Temperature Stress on Some Physiological Characteristics of Maize Zea mays L.(

    Directory of Open Access Journals (Sweden)

    M Attarzadeh

    2015-04-01

    Full Text Available The present study was conducted to evaluate the effects of salicylic acid and High temperature on physiological characteristics of maize (cv. SC704. In order to, a factorial experiment based on randomized complete blocks design with three replications was carried out in Research Greenhouse of Vali-e-Asr University of Rafsanjan. The factors were included pre-treatment of concentrations of salicylic acid (0, 50, 100 and 200 μM and duration of 40°C (0, 8, 16 and 24 hours. Results showed that SPAD index increased significantly in levels of 50 and 100μM salicylic acid but it was low in control and 200μM salicylic acid. In level of 50μM salicylic acid, increase in duration of heat stress was resulted in increasing content of a and ab chlorophyll. However, it was occurred conversely in level of 200 μM salicylic acid, i.e., content of a and ab was decreased. Levels of salicylic acid and duration of heat stress did not effect on Fv/Fm and content of soluble sugar. Use of 200 μM salicylic acid decreased significantly relative water content, while increase in duration of heat stress caused to increase relative water content. In addition, increase in duration of heat stress resulted in increasing leaf temperature and proline content.

  17. A first insight into temperature stress-induced neuroendocrine and immunological changes in giant freshwater prawn, Macrobrachium rosenbergii.

    Science.gov (United States)

    Chang, Chin-Chyuan; Jiang, Jia-Rong; Cheng, Winton

    2015-11-01

    Haemolymph norepinephrine (NE); total haemocyte count (THC); respiratory bursts (RBs); superoxide dismutase (SOD), phenoloxidase (PO), and phagocytic activity; and prophenoloxidase (proPO)-system-related genes (lipopolysaccharide- and β-1,3-glucan-binding protein: LGBP, proPO, peroxinectin: PE, and α2-macroglobulin: α2-M) in haemocytes of Macrobrachium rosenbergii were investigated after transferring them from 28 °C to 22 °C, 28 °C, and 34 °C respectively. The results revealed that haemolymph NE, hyaline cells (HCs), and PO activity per granulocyte increased from 30 to 120 min of exposure, and however, RBs and phagocytic activity significantly decreased from 30 to 120 min of exposure as well as granular cells (GCs), semigranular cells (SGCs), and SOD activity decreased from 60 to 120 min of exposure for the prawns subjected to temperature stress. The proPO-system-related gene expression markedly increased with 60-120 min of exposure for the prawns transferred from 28 °C to 22 °C and 34 °C, except α2M at 120 min. These results provide a first insight into the effects of temperature stress on haemolymph NE level and immune functions in prawns and suggest that temperature-stress-induced acute modulation in immunity is associated with the release of haemolymph NE in M. rosenbergii. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Modifications of system for elevated temperature tensile testing and stress-strain measurement of metal matrix composites

    Science.gov (United States)

    Diaz, J. O.

    1985-01-01

    Composites consisting of tungsten alloy wires in superalloy matrices are being studied because they offer the potential for increased strength compared to current materials used at temperatures up to at least 1093 C (2000F). Previous research at the NASA Lewis Research Center and at other laboratories in the U.S., Europe, and Japan has demonstrated laboratory feasibility for fiber reinforced superalloys (FRS). The data for the mechanical and physical properties used to evaluate candidate materials is limited and a need exists for a more detailed and complete data base. The focus of this work is to develop a test procedure to provide a more complete FRS data base to quantitatively evaluate the composite's potential for component applications. This paper will describe and discuss the equipment and procedures under development to obtain elevated temperature tensile stress-strain, strength and modulus data for the first generation of tungsten fiber reinforced superalloy composite (TFRS) materials. Tensile stress-strain tests are conducted using a constant crosshead speed tensile testing machine and a modified load-strain measuring apparatus. Elevated temperature tensile tests are performed using a resistance wound commercial furnace capable of heating test specimens up to 1093 C (2000 F). Tensile stress-strain data are obtained for hollow tubular stainless steel specimens serving as a prototype for future composite specimens.

  19. Biosynthesis and uptake of glycine betaine as cold-stress response to low temperature in fish pathogen Vibrio anguillarum.

    Science.gov (United States)

    Ma, Yue; Wang, Qiyao; Gao, Xiating; Zhang, Yuanxing

    2017-01-01

    Fish pathogen Vibrio anguillarum, a mesophile bacterium, is usually found in estuarine and marine coastal ecosystems worldwide that pose a constant stress to local organism by its fluctuation in salinity as well as notable temperature change. Though V. anguillarum is able to proliferate while maintain its pathogenicity under low temperature (5-18°C), so far, coldadaption molecular mechanism of the bacteria is unknown. In this study, V. anguillarum was found possessing a putative glycine betaine synthesis system, which is encoded by betABI and synthesizes glycine betaine from its precursor choline. Furthermore, significant up-regulation of the bet gene at the transcriptional level was noted in log phase in response to cold-stress. Moreover, the accumulation of betaine glycine was only found appearing at low growth temperatures, suggesting that response regulation of both synthesis system and transporter system are cold-dependent. Furthermore, in-frame deletion mutation in the two putative ABC transporters and three putative BCCT family transporters associated with glycine betaine uptake could not block cellular accumulation of betaine glycine in V. anguillarum under coldstress, suggesting the redundant feature in V. anguillarum betaine transporter system. These findings confirmed that glycine betaine serves as an effective cold stress protectant and highlighted an underappreciated facet of the acclimatization of V. anguillarum to cold environments.

  20. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress*

    Science.gov (United States)

    Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia

    2009-01-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 °C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60~64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress. PMID:19489108

  1. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress.

    Science.gov (United States)

    Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia

    2009-06-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 degrees C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60 approximately 64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress.

  2. Low Temperature Stress Induced Changes in Biochemical Parameters, Protein Banding Pattern and Expression of Zat12 and Myb Genes in Rice Seedling

    Directory of Open Access Journals (Sweden)

    Salma Perveen

    2013-11-01

    Full Text Available Low temperature stress is one of the main abiotic factors that reduce the productivity of many crops in hilly areas around the world. In this study, rice seedling were exposed to low temperature stress (control, 0°C, -2°C, -4°C and -6°C for 2 hr to observe its effect on two rice varieties (Basmati-385 and Shaheen Basmati through ion and proline contents, photosynthetic pigments, total protein content, protein banding pattern and expression of Zat12 and Myb genes. Resulted showed different patterns of accumulation of Na+ K+ and Ca+2 ions with the decrease in temperature in both varieties. Proline accumulation was gradually increased in both varieties with the decrease in temperature. Photosynthetic pigments (Chlorophyll (Chl a, b and carotene were negatively affected by low temperature stress in both varieties, however, carotene content was much affected than Chl a and b. Nonsignificant variation in protein contents was observed at all levels of low temperature, but the effects of low temperature stress on protein banding pattern of Basmti-385 and Shaheen Basmati were different at different treatments. RT-PCR results indicated that ZAT12 was upregulated by short term low temperature stress while OsMYB show slight upregulation at -2°C as compared to the other treatments. This study identified that ZAT12 and OsMYB function as a positive regulator to mediate tolerance of rice seedlings at low temperature stress.

  3. Antioxidant responses and photosynthetic behaviors of Kappaphycus alvarezii and Kappaphycus striatum (Rhodophyta, Solieriaceae) during low temperature stress.

    Science.gov (United States)

    Li, Hu; Liu, Jianguo; Zhang, Litao; Pang, Tong

    2016-12-01

    Kappaphycus are farmed in tropical countries as raw material for carrageenan, which is widely used in food industry. The sea area available for farming is one limiting factor in the production of seaweeds. Though cultivation is spreading into subtropical regions, the lower seawater temperature is an important problem encountered in subtropical regions for the farming of Kappaphycus. This research of physiological response to low temperature stress will be helpful for screening Kappaphycus strains for growth in a lower temperature environment. Responses of antioxidant systems and photosystem II (PSII) behaviors in Kappaphycus alvarezii and Kappaphycus striatum were evaluated during low temperature treatments (23, 20, 17 °C). Compared with the controls at 26 °C, the H 2 O 2 concentrations increased in both species when the thalli were exposed to low temperatures (23, 20, 17 °C), but these increases were much greater in K. striatum than in K. alvarezii thalli, suggesting that K. striatum suffered more oxidative stress. The activities of some important antioxidant enzymes (e.g. superoxide dismutase and ascorbate peroxidase) and the hydroxyl free radical scavenging capacity were substantially higher at 23, 20 and 17 °C than at the control 26 °C in K. alvarezii, indicating that the antioxidant system of K. alvarezii enhanced its resistance to low temperature. However, no significant increases of antioxidant enzymes activities were observed at 20 and 17 °C in K. striatum. In addition, both the maximal efficiency of PSII photochemistry (F V /F m ) and the performance index (PI ABS ) decreased significantly in K. striatum at 23 °C, indicating that the photosynthetic apparatus was damaged at 23 °C. In contrast, no significant decreases of either F V /F m or PI ABS were observed in K. alvarezii at 23 °C. It is concluded that K. alvarezii has greater tolerance to low temperature than K. striatum.

  4. Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century

    Science.gov (United States)

    Coffel, Ethan D.; Horton, Radley M.; de Sherbinin, Alex

    2018-01-01

    As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100-250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world’s population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150-750 million person-days of exposure to wet bulb temperatures above those seen in today’s most severe heat waves by 2070-2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.

  5. Seed germination response to high temperature and water stress in three invasive Asteraceae weeds from Xishuangbanna, SW China.

    Science.gov (United States)

    Yuan, Xia; Wen, Bin

    2018-01-01

    Crassocephalum crepidioides, Conyza canadensis, and Ageratum conyzoides are alien annuals naturalized in China, which produce a large number of viable seeds every year. They widely grow in Xishuangbanna, becoming troublesome weeds that compete with crops for water and nutrients. As seed germination is among the most important life-stages which contribute to plant distribution and invasiveness, its adaptation to temperature and water stress were investigated in these three species. Results showed that: (1) These three species have wide temperature ranges to allow seed germination, i.e., high germination and seedling percentages were achieved between 15°C and 30°C, but germination was seriously inhibited at 35°C; only A. conyzoides demonstrated relative preference for warmer temperatures with approximately 25% germination and seedling percentage at 35°C; (2) light was a vital germination prerequisite for C. crepidioides and A. conyzoides, whereas most C. canadensis seeds germinated in full darkness; (3) Although all three species have good adaptation to bare ground habitat characterized by high temperatures and water stress, including their tolerance to soil surface temperatures of 70°C in air-dried seeds, A. conyzoides seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 40°C, and to water restriction (e.g., ca. 65% seeds germinated to -0.8 MPa created by NaCl), which is consistent with their field behavior in Xishuangbanna. This study suggests that seed high-temperature tolerance contributes to the weed attributes of these three species, and that adaptation to local micro-habitats is a critical determinant for invasiveness of an alien plant.

  6. Alternate stresses and temperature variation as factors of influence of ultrasonic vibration on mechanical and functional properties of shape memory alloys.

    Science.gov (United States)

    Belyaev, Sergey; Volkov, Alexander; Resnina, Natalia

    2014-01-01

    It is known that the main factors in a variation in the shape memory alloy properties under insonation are heating of the material and alternate stresses action. In the present work the experimental study of the mechanical behaviour and functional properties of shape memory alloy under the action of alternate stresses and varying temperature was carried out. The data obtained had demonstrated that an increase in temperature of the sample resulted in a decrease or increase in deformation stress depending on the structural state of the TiNi sample. It was shown that in the case of the alloy in the martensitic state, a decrease in stress was observed, and on the other hand, in the austenitic state an increase in stress took place. It was found that action of alternate stresses led to appearance of strain jumps on the strain-temperature curves during cooling and heating the sample through the temperature range of martensitic transformation under the constant stress. The value of the strain jumps depended on the amplitude of alternate stresses and the completeness of martensitic transformation. It was shown that the heat action of ultrasonic vibration to the mechanical behaviour of shape memory alloys was due to the non-monotonic dependence of yield stress on the temperature. The force action of ultrasonic vibration to the functional properties was caused by formation of additional oriented martensite. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Relation between the celestial tide-generating stress and the temperature variations of the Abruzzo M = 6.3 Earthquake in April 2009

    Directory of Open Access Journals (Sweden)

    F. S. Li

    2012-03-01

    Full Text Available The temperature variations caused by additive tectonic stress has been studied to explain its relationship with the seismic fault sliding of the Abruzzo M = 6.3 Earthquake in April 2009. According to the periodic changes of the additive tectonic stress caused by the celestial tide-generating force, the temperature variations before and after the earthquake have been analyzed based on the temperature data from National Centers for Environmental Prediction (NCEP. The figures of temperature variations clearly show that the abnormal increasing of the temperature has resulted from seismic fault sliding. Based on this method, it is possible to forewarn short-impending earthquakes.

  8. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [south Texas

    Science.gov (United States)

    Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

    1981-01-01

    Emissive and reflective data for 10 days, and IR data for 6 nights in south Texas scenes were analyzed after procedures were developed for removing cloud-affected data. HCMM radiometric temperatures were: within 2 C of dewpoint temperatures on nights when air temperature approached dewpoint temperatures; significantly correlated with variables important in evapotranspiration; and, related to freeze severity and planting depth soil temperatures. Vegetation greenness indexes calculated from visible and reflective IR bands of NOAA-6 to -9 meteorological satellites will be useful in the AgRISTARS program for seasonal crop development, crop condition, and drought applications.

  9. Cold priming drives the sub-cellular antioxidant systems to protect photosynthetic electron transport against subsequent low temperature stress in winter wheat

    DEFF Research Database (Denmark)

    Li, Xiangnan; Cai, Jian; Liu, Fulai

    2014-01-01

    Low temperature seriously depresses the growth of wheat through inhibition of photosynthesis, while earlier cold priming may enhance the tolerance of plants to subsequent low temperature stress. Here, winter wheat plants were firstly cold primed (5.2°C lower temperature than the ambient temperatu...

  10. Rock outcrops reduce temperature-induced stress for tropical conifer by decoupling regional climate in the semiarid environment.

    Science.gov (United States)

    Locosselli, Giuliano Maselli; Cardim, Ricardo Henrique; Ceccantini, Gregório

    2016-05-01

    We aimed to understand the effect of rock outcrops on the growth of Podocarpus lambertii within a microrefuge. Our hypothesis holds that the growth and survival of this species depend on the regional climate decoupling provided by rock outcrops. To test this hypothesis, we characterized the microclimate of (1) surrounding vegetation, (2) rock outcrop corridors, and (3) adjacencies. We assessed population structure by collecting data of specimen stem diameter and height. We also assessed differences between vegetation associated or not with outcrops using satellite imaging. For dendrochronological analyses, we sampled 42 individuals. Tree rings of 31 individuals were dated, and climate-growth relationships were tested. Rock outcrops produce a favorable microclimate by reducing average temperature by 4.9 °C and increasing average air humidity by 12 %. They also reduce the variability of atmospheric temperature by 42 % and air humidity by 20 % supporting a vegetation with higher leaf area index. Within this vegetation, specimen height was strongly constrained by the outcrop height. Although temperature and precipitation modulate this species growth, temperature-induced stress is the key limiting growth factor for this population of P. lambertii. We conclude that this species growth and survival depend on the presence of rock outcrops. These topography elements decouple regional climate in a favorable way for this species growth. However, these benefits are restricted to the areas sheltered by rock outcrops. Although this microrefuge supported P. lambertii growth so far, it is unclear whether this protection would be sufficient to withstand the stress of future climate changes.

  11. Cleanup Verification Package for the 118-B-1, 105-B Solid Waste Burial Ground

    International Nuclear Information System (INIS)

    Capron, J.M.

    2008-01-01

    This cleanup verification package documents completion of remedial action, sampling activities, and compliance criteria for the 118-B-1, 105-B Solid Waste Burial Ground. This waste site was the primary burial ground for general wastes from the operation of the 105-B Reactor and P-10 Tritium Separation Project and also received waste from the 105-N Reactor. The burial ground received reactor hardware, process piping and tubing, fuel spacers, glassware, electrical components, tritium process wastes, soft wastes and other miscellaneous debris

  12. GPR and bulk ground resistivity surveys in graveyards: locating unmarked burials in contrasting soil types.

    Science.gov (United States)

    Hansen, James D; Pringle, Jamie K; Goodwin, Jon

    2014-04-01

    With graveyards and cemeteries globally being increasingly designated as full, there is a growing need to identify unmarked burial positions to find burial space or exhume and re-inter if necessary. In some countries, for example the U.S. and U.K., burial sites are not usually re-used; however, most graveyard and cemetery records do not have maps of positions. One non-invasive detection method is near-surface geophysics, but there has been a lack of research to-date on optimal methods and/or equipment configuration. This paper presents three case studies in contrasting burial environments, soil types, burial styles and ages in the U.K. Geophysical survey results reveal unmarked burials could be effectively identified from these case studies that were not uniform or predicted using 225 MHz frequency antennae GPR 2D 0.5 m spaced profiles. Bulk ground electrical surveys, rarely used for unmarked burials, revealed 1 m probe spacings were optimal compared to 0.5 m, with datasets needing 3D detrending to reveal burial positions. Results were variable depending upon soil type; in very coarse soils GPR was optimal; whereas resistivity was optimal in clay-rich soils and both were optimal in sandy and black earth soils. Archaeological excavations revealed unmarked burials, extra/missing individuals from parish records and a variety of burial styles from isolated, brick-lined, to vertically stacked individuals. Study results, evidence unmarked burial targets were significantly different from clandestine burials of murder victims which are used as analogues. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Exploring sustainable burial practices in South Africa: Potential challenges and opportunities

    CSIR Research Space (South Africa)

    Leuta, T

    2011-10-01

    Full Text Available ; Moreosele et al, 2011) and alternatives to traditional burial1 (Davids, 2011). Burial in South Africa remains the most popular end-of-life choice, and is by far the most commonly used by members of Islamic, Christian, Jewish and traditional African faiths... provides challenges due to insufficient suitable and affordable land for future burial needs. For this method to become a more culturally- acceptable practice it requires education and publicity of the choices and implications (including costs) regarding...

  14. Optimal temperature profiles for minimum residual stress in the cure process of polymer composites

    CSIR Research Space (South Africa)

    Gopal, AK

    2000-01-01

    Full Text Available model which includes the effects of chemical and thermal strains and the viscoelastic material behaviour. The process model is implemented to conduct a parametric study to observe the trends and characteristics of the residual stress history varying...

  15. Phenolic compounds and properties of antioxidants in grapevine roots (Vitis vinifera L. under low-temperature stress followed by recovery

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2011-01-01

    Full Text Available The research has been performed on roots of Vitis vinifera, cv. Himrod, obtained from seedlings grown under chill stress conditions (+10oC in the day and +7oC at night, under optimum conditions (+25oC in the day and +18oC at night and from seedling which underwent a recover period after the chill stress treatment. The purpose of the study has been to determine quantitative and qualitative changes in phenolic compounds as well as to demonstrate changes in antiradical properties of extracts from grapevine roots, which appeared as a result of chill stress and during recovery under the optimum conditions following the stress. Phenolic compounds from grapevine roots were extracted using 80% acetone. The total content of phenolics was determined by colorimetry. The content of tannins was tested by precipitation with bovine serum albumin. The reducing power as well as DPPH• free radical and ABTS+• cation radical scavenging activity of the extracts were also tested. In order to identify phenolic compounds present in the extracts the RP-HPLC technique was employed. The tested material was found to contain tannins and three identified phenolic acids: ferulic, caffeic and p-coumaric ones. The latter occurred in the highest concentrations (from 4.46 to 6.28 µg/g fresh matter. Ferulic acid appeared in smaller amounts (from 1.68 to 2.65 µg/g fresh matter, followed by caffeic acid (from 0.87 to 1.55 µg/g fresh matter. Significantly less total phenolic compounds occurred in roots of seedlings subjected to chill stress. However, the total content of these compounds increased significantly in roots of plants which underwent recovery after chill stress. Concentration of tannins was determined by two methods. The content of condensed tannins was depressed in roots as a result of low temperature stress, whereas the content of condensed and hydrolysing tannins (determined via the BSA method rose under chill stress conditions. A significant increase in tannins

  16. Survival of Salmonella serovars on beef carcasses and molecular mechanisms to survive low temperature stress and desiccation

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Thomsen, Line Elnif; Aabo, Søren

    2006-01-01

    . Infantis and S. Newport. This experiment indicates that storage at low temperature of beef carcasses can be used as a reduction strategy for Salmonella spp. in beef. In addition molecular mechanisms to resist low temperature stress and desiccation have been investigated. Mutants in the otsA, rpoS and clp...... at 10°C and 15°C, the ¿clpP mutant was severely affected in ability to form colonies compared to the wildtype. Neither the ¿otsA nor the ¿rpoS were affected in growth or survival at low temperature. In a desiccation model, both the ¿rpoS and ¿clpP mutant were more sensitive than the C5 wildtype...

  17. Biomass burial and storage to reduce atmospheric CO2

    Science.gov (United States)

    Zeng, N.

    2012-04-01

    To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a theoretical carbon sequestration potential for wood burial is 10 ± 5 GtC/y, but probably 1-3 GtC/y can be realized in practice. Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other environmental concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from forest industry, the cost for wood burial is estimated to be 14/tCO2 (50/tC), lower than the typical cost for power plant CO2 capture with geological storage. The low cost for carbon sequestration with wood burial is possible because the technique uses the natural process of photosynthesis to remove carbon from the atmosphere. The technique is low tech, distributed, safe, and can be stopped at any time, thus an attractive option for large-scale implementation in a world-wide carbon market.

  18. Shallow land burial of low-level radioactive waste

    International Nuclear Information System (INIS)

    Cannon, J.B.; Jacobs, D.G.; Lee, D.W.

    1986-02-01

    The performance objectives included in regulations for disposal of low-level radioactive waste (10 CFR 61 for commercial waste and DOE Order 5820.2 for defense waste) are generic principles that generate technical requirements which must be factored into each phase of the development and operation of a shallow land burial facility. These phases include a determination of the quantity and characteristics of the waste, selection of a site and appropriate facility design, use of sound operating practices, and closure of the facility. The collective experience concerning shallow land burial operations has shown that achievement of the performance objectives (specifically, waste isolation and radionuclide containment) requires a systems approach, factoring into consideration the interrelationships of the phases of facility development and operation and their overall impact on performance. This report presents the technical requirements and procedures for the development and operation of a shallow land burial facility for low-level radioactive waste. The systems approach is embodied in the presentation. The report is not intended to be an instruction manual; rather, emphasis is placed on understanding the technical requirements and knowing what information and analysis are needed for making informed choices to meet them. A framework is developed for using the desired site characteristics to locate potentially suitable sites. The scope of efforts necessary for characterizing a site is then described and the range of techniques available for site characterization is identified. Given the natural features of a site, design options for achieving the performance objectives are discussed, as are the operating practices, which must be compatible with the design. Site closure is presented as functioning to preserve the containment and isolation provided at earlier stages of the development and operation of the facility

  19. Continuous Monitoring of Mobility, Burial and Re exposure of Underwater Munitions in Energetic Near Shore Environments

    Science.gov (United States)

    2017-01-01

    to planning remediation efforts. In sandy, energetic, nearshore environments, the migration , burial, and reexposure processes all have the...8 Theory ...31 Discussion of Theory and Hydrodynamic Forcing

  20. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    DEFF Research Database (Denmark)

    Freiesleben, Trine Holm; Sohbati, Reza; Murray, Andrew

    2015-01-01

    luminescence-depth profile from a feldspar-rich granite cobble from an archaeological site near Aarhus, Denmark. This profile shows qualitative evidence for multiple daylight exposure and burial events; these are quantified using the model developed here. By determining the burial ages from the surface layer...... of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure...

  1. Closure Plan for Active Low Level Burial Grounds

    Energy Technology Data Exchange (ETDEWEB)

    SKELLY, W.A.

    2000-11-16

    This plan has been prepared in response to direction from the U.S. Department of Energy. The purpose of the plan is to define approaches that will be implemented to ensure protection of the public and the environment when active Low-Level Burial Grounds (LLBGs) at the Hanford Site are closed. Performance assessments for active burial grounds in the 200 East and West 200 Areas provide current estimates of potential environmental contamination and doses to the ''maximum exposed individual'' from burial ground operation and closure and compare dose estimates to performance objective dose limits for the facilities. This is an Operational Closure Plan. The intent of the guidance in DOE Order 435.1 is that this plan will be a living document, like the facility performance assessments, and will be revised periodically through the operational life of the LLBGs to reflect updated information on waste inventory. management practices, facility transition planning, schedule dates, assessments of post-closure performance, and environmental consequences. Out year dates identified in this plan are tentative. A Final Closure Plan will be prepared in the future when the timing and extent of closure-related activities for LLBGs can be established with greater certainty. After current operations at the LLBGs are concluded, this plan proposes transitioning of these facilities to the Environmental Restoration Program. This action will enable the Environmental Restoration Program to design and implement consistent and coordinated final remedial actions for active and inactive LLBGs. Active and inactive burial grounds in the 200 West and 200 East Areas are commingled. This plan describes approaches that will be implemented during Interim Closure, Final Closure, and Institutional Control Periods to prepare LLBGs for surface barriers, and the construction of barriers, as well as the scope of inspection, monitoring and maintenance practices that will be performed during

  2. Hydrogeology of the 200 Areas low-level burial grounds

    International Nuclear Information System (INIS)

    Last, G.V.; Bjornstad, B.N.; Bergeron, M.P.

    1989-01-01

    This report presents information derived form the installation of 35 ground-water monitoring wells around six low-level radioactive/hazardous waste burial grounds located in the 200 Areas of the Hanford Site in southeastern Washington State. This information was collected between May 20, 1987 and August 1, 1988. The contents of this report have been divided into two volumes. Volume 1 contains the main text. This Volume contains the appendixes, including data and supporting information that verify content and results found in the main text

  3. Organic Carbon Burial Rates in Mangrove Soils Along Florida's Coast from Tampa Bay to Biscayne National Park

    Science.gov (United States)

    Smoak, J. M.; Breithaupt, J. L.; Moyer, R. P.; Sanders, C. J.; Proctor, M. R.; Jacobs, J. A.; Chappel, A. R.; Comparetto, K. R.

    2016-12-01

    Mangrove forests provide a range of valuable ecosystem services including sequestering organic carbon (OC) in their soils at rates much greater on a per area basis than those found in other types of forests. This restricts a large quantity of OC to a relatively small area along tropical and sub-tropical coastal margins, where dramatic climate-driven impacts are expected. Hence this small yet highly-vulnerable area will have a disproportionally large impact on global carbon cycling. One of the fundamental climate-related questions in mangrove systems is whether their soils will continue to function as a globally significant OC sink or become a source as previously buried OC is oxidized and returned to the atmosphere. While changes to precipitation, temperature, cyclone activity, etc. may influence this sink capacity, it is accelerating sea-level rise (SLR) that is of greatest immediate concern because if mangrove peat formation fails to keep pace then all ecosystem services, including carbon burial, will collapse. Mangroves that receive minimal terrigenous sediments (such as those in South Florida) are largely dependent on the rate of OC accumulation as a key contributor to accretion. To investigate these processes, we measured OC burial and accretion rates over the last 100 years (via 210Pb dating) from sites in Tampa Bay, Charlotte Harbor, Ten Thousand Islands, Everglades National Park, Biscayne National Park, and the Lower Florida Keys. The mean 100-year burial rate over all sites is 119 ± 33 (SD) g m-2 yr-1 which is lower than the global mean. Mean accretion rates were found to match (within error) the relatively modest average SLR over the last 100 years, but rates may not have kept pace with the substantially higher SLR in the last decade. This investigation contributes to establishing regional-scale Blue Carbon budgets, and examines how OC burial in mangroves has changed over the last 100 years. This improved understanding of past mangrove OC burial response

  4. temperature

    Directory of Open Access Journals (Sweden)

    G. Polt

    2015-10-01

    Full Text Available In-situ X-ray diffraction was applied to isotactic polypropylene with a high volume fraction of α-phase (α-iPP while it has been compressed at temperatures below and above its glass transition temperature Tg. The diffraction patterns were evaluated by the Multi-reflection X-ray Profile Analysis (MXPA method, revealing microstructural parameters such as the density of dislocations and the size of coherently scattering domains (CSD-size. A significant difference in the development of the dislocation density was found compared to compression at temperatures above Tg, pointing at a different plastic deformation mechanism at these temperatures. Based on the individual evolutions of the dislocation density and CSD-size observed as a function of compressive strain, suggestions for the deformation mechanisms occurring below and above Tg are made.

  5. Analysis of temperature and thermal stress fields of K9 glass damaged by 1064nm nanosecond pulse laser

    Science.gov (United States)

    Pan, Yunxiang; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2013-02-01

    There are residual scratches, inclusions and other forms of defects at surfaces of optical materials after the processes of grinding and polishing, which could either enhance the local electric field or increase the absorption rate of the material. As a result, the laser-induced damage threshold at the surface of the material is reduced greatly. In order to study underlying mechanisms and process of short pulsed laser-induced damage to K9 glass, a spatial axisymmetric model where the K9 glass was irradiated by a laser whose wavelength and pulse width are respectively 1064nm and 10ns was established. Taking into account the fact that the surface of the K9 glass is more likely to be damaged, 2μm-thick layers whose absorption coefficients are larger than bulk were set at both the input and output surfaces in the model. In addition, the model assumed that once the calculated tensile/compressive stress was greater than the tensile/compressive strength of K9 glass, the local absorption coefficient increased. The finite element method(FEM) was applied to calculate the temperature and thermal stress fields in the K9 glass. Results show that only the temperature of a small part of interacted region exceeds the melting point, while most of the damage pit is generated by thermal stress. The simulated damage morphology and the size of the damage region are consistent with those reported in literatures, which indicates that the model built in our work is reasonable.

  6. Pseudo-variables method to calculate HMA relaxation modulus through low-temperature induced stress and strain

    International Nuclear Information System (INIS)

    Canestrari, Francesco; Stimilli, Arianna; Bahia, Hussain U.; Virgili, Amedeo

    2015-01-01

    Highlights: • Proposal of a new method to analyze low-temperature cracking of bituminous mixtures. • Reliability of the relaxation modulus master curve modeling through Prony series. • Suitability of the pseudo-variables approach for a close form solution. - Abstract: Thermal cracking is a critical failure mode for asphalt pavements. Relaxation modulus is the major viscoelastic property that controls the development of thermally induced tensile stresses. Therefore, accurate determination of the relaxation modulus is fundamental for designing long lasting pavements. This paper proposes a reliable analytical solution for constructing the relaxation modulus master curve by measuring stress and strain thermally induced in asphalt mixtures. The solution, based on Boltzmann’s Superposition Principle and pseudo-variables concepts, accounts for time and temperature dependency of bituminous materials modulus, avoiding complex integral transformations. The applicability of the solution is demonstrated by testing a reference mixture using the Asphalt Thermal Cracking Analyzer (ATCA) device. By applying thermal loadings on restrained and unrestrained asphalt beams, ATCA allows the determination of several parameters, but is still unable to provide reliable estimations of relaxation properties. Without them the measurements from ATCA cannot be used in modeling of pavement behavior. Thus, the proposed solution successfully integrates ATCA experimental data. The same methodology can be applied to all test methods that concurrently measure stress and strain. The statistical parameters used to evaluate the goodness of fit show optimum correlation between theoretical and experimental results, demonstrating the accuracy of this mathematical approach

  7. Temperature-dependent bias-stress-induced electrical instability of amorphous indium-gallium-zinc-oxide thin-film transistors

    Science.gov (United States)

    Qian, Hui-Min; Yu, Guang; Lu, Hai; Wu, Chen-Fei; Tang, Lan-Feng; Zhou, Dong; Ren, Fang-Fang; Zhang, Rong; Zheng, You-Liao; Huang, Xiao-Ming

    2015-07-01

    The time and temperature dependence of threshold voltage shift under positive-bias stress (PBS) and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτstress = 0.72 eV for the PBS process and an average effective energy barrier Eτrecovery = 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB301900 and 2011CB922100) and the Priority Academic Program Development of Jiangsu Higher Education Institutions, China

  8. Bias temperature stress induced hydrogen depassivation from Al2O3/InGaAs interface defects

    Science.gov (United States)

    Tang, Kechao; Droopad, Ravi; McIntyre, Paul C.

    2018-01-01

    We study the reliability of Al2O3/InGaAs metal-oxide-semiconductor gate stacks by investigating the effect of bias temperature stress on the charge trap density at the Al2O3/InGaAs interface and in the bulk oxide. Under extended negative biasing at 100 °C, the gate stacks display a notable increase in the interface trap density (Dit), but little change in the border trap density. This phenomenon is more prominent for samples exposed to a H2/N2 forming gas anneal (FGA) than for the as-deposited samples. Negative gate bias applied during 100 °C thermal stress negates the FGA-induced passivation of interface states and causes convergence of the Dit of the post-FGA and as-deposited gate stacks with increasing biasing time. This appears to be caused by hydrogen depassivation of interface traps under bias temperature stress, which is further supported by an observed hydrogen isotope effect when comparing the rate of Dit increase after annealing in hydrogenated versus deuterated forming gas. A N2 anneal control experiment also indicates that the stability of the interface trap density of post-FGA Al2O3/InGaAs gate stacks is more strongly influenced by the behavior of hydrogen at the interface than by the thermal treatment effect of the anneal.

  9. Thawing of permafrost may disturb historic cattle burial grounds in East Siberia

    Directory of Open Access Journals (Sweden)

    Boris A. Revich

    2011-11-01

    Full Text Available Climate warming in the Arctic may increase the risk of zoonoses due to expansion of vector habitats, improved chances of vector survival during winter, and permafrost degradation. Monitoring of soil temperatures at Siberian cryology control stations since 1970 showed correlations between air temperatures and the depth of permafrost layer that thawed during summer season. Between 1900s and 1980s, the temperature of surface layer of permafrost increased by 2–4°C; and a further increase of 3°C is expected. Frequent outbreaks of anthrax caused death of 1.5 million deer in Russian North between 1897 and 1925. Anthrax among people or cattle has been reported in 29,000 settlements of the Russian North, including more than 200 Yakutia settlements, which are located near the burial grounds of cattle that died from anthrax. Statistically significant positive trends in annual average temperatures were established in 8 out of 17 administrative districts of Yakutia for which sufficient meteorological data were available. At present, it is not known whether further warming of the permafrost will lead to the release of viable anthrax organisms. Nevertheless, we suggest that it would be prudent to undertake careful monitoring of permafrost conditions in all areas where an anthrax outbreak had occurred in the past.

  10. Micromorphology of two prehistoric ritual burials from Yemen, and considerations on methodological aspects of sampling the burial matrix - work in progress

    Science.gov (United States)

    Usai, Maria-Raimonda; Brothwell, Don; Buckley, Stephen; Ai-Thour, Kalid; Canti, Matthew

    2010-05-01

    Introduction In the central area of Yemen, two burial sites placed high in the crevices of vertical cliff face of Cretaceous sandstone (Tawilah Group) provided evidence of human remains and yielded burial soils. Radiocarbon dating indicated c.2500-2900 years BP for the burials. In other local comparable sites the deep horizontal crevices yielded Bronze Age human remains, in exceptional state of preservation Questions: What was the nature of the burial matrix? Are other human influences superimposed on the soils derived from it? Is it simply decomposed crevice rock, scraped together at the time of burial, or the result of a more complex burial practice? Such questions are also relevant to a variety of other burials of different periods and world regions. Methods Seven matrix samples from Cliff Burials (A) Talan (Layers 4,10,12,14,18,20 and 22, from top to bottom) and (B) Shiban Kawkaban (Layer 1 and 9) were analysed with micromorphology, supplemented by SEM microprobe, X-ray diffraction, gas chromatography/mass spectrometry. Results Cliff Burial Site Talan. The presence of cholesterol was confirmed in the lower sample. The second layer contained darker earth with fibrous plant material. A hard calcareous upper capping contrasted with the other levels of matrix, and it displayed a highly birefingent material with a significant component of uric acid. The other levels had variable organic content and plant inclusions, and possibly pollen. In Layer 10, aromatic acids indicative of balsam and sugar markers suggested plant gum. Cholesterol was the major sterol in Layers 10 and 22, but whilst in Layer 10 its oxidation products were present and cholestanol was abundant as normally in soils, it was only a minor component of Layer 22 where, rather, a significant amount of coprostanol indicated faecal input, and cholesterol oxidation products were absent. Cliff Burial Site Shiban Kawkaban. Although no stratification was visible to the naked eye, variation was observed at a

  11. Determination of the optimum temperature history of inlet water for minimizing thermal stresses in a pipe by the multiphysics inverse analysis

    International Nuclear Information System (INIS)

    Kubo, S; Uchida, K; Ishizaka, T; Ioka, S

    2008-01-01

    It is important to reduce the thermal stresses for managing and extending the lives of pipes in plants. In this problem, heat conduction, elastic deformation, heat transfer, liquid flow should be considered, and therefore the problem is of a multidisciplinary nature. An inverse method was proposed by the present authors for determining the optimum thermal load history which reduced transient thermal stress considering the multidisciplinary physics. But the obtained solution had a problem that the temperature increasing rate of inner surface of the pipe was discontinuous at the end time of heat up. In this study we introduce temperature history functions that ensure the continuity of the temperature increasing rate. The multidisciplinary complex problem is decomposed into a heat conduction problem, a heat transfer problem, and a thermal stress problem. An analytical solution of the temperature distribution of radial thickness and thermal hoop stress distribution is obtained. The maximum tensile and compressive hoop stresses are minimized for the case where inner surface temperature T s (t) is expressed in terms of the 4th order polynomial function of time t. Finally, from the temperature distributions, the optimum fluid temperature history is obtained for reducing the thermal stresses.

  12. Stress !!!

    OpenAIRE

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten. Opvallend is dat mannelijke studenten uit Twente zich veel minder druk lijken te maken over hun studie. Onder vrouwen ligt de stress juist erg hoog ten opzichte van het landelijk gemiddelde.

  13. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  14. Effect of Filler Size and Temperature on Packing Stress and Viscosity of Resin-composites

    OpenAIRE

    Elbishari, Haitham; Satterthwaite, Julian; Silikas, Nick

    2011-01-01

    The objective of this study was to investigate the effect of filler size on the packing stress and viscosity of uncured resin-composite at 23 °C and 37 °C. A precision instrument used was designed upon the penetrometer principle. Eight resin-composite materials were tested. Packing-stress ranged from 2.60 to 0.43 MPa and viscosity ranged from 2.88 to 0.02 MPa.s at 23 °C. Values for both properties were reduced significantly at 37 °C. Statistical analysis, by ANOVA and post hoc methods, were c...

  15. Seed germination of three provenances of Pinus brutia (Ten.) as influenced by stratification, temperature and water stress.

    Science.gov (United States)

    Tilki, Fahrettin; Dirik, Huseyin

    2007-01-01

    Seeds from three provenances of Pinus brutia were stratified for 0 or 45 d (days) at 4 +/- 1 degrees C and then germinated at 15 degrees C or 20 degrees C on filter paper saturated with polyethylene glycol solutions to provide water potentials of 0, -0.2 and -0.4 MPa (mega Pascal). Regardless of stratification, germination was lower at 15 degrees C than 20 degrees C for seeds of all provenances. Stratification significantly increased germination percentage at all water potentials regardless of the germination temperatures. Lowering the water potential to -0.4 MPa reduced germination for all three provenances in unstratified and stratified seeds when averaged for two temperatures, but reaction to the increased water stress was different among the provenances. Combined over two temperatures, stratified or unstratified seeds from the highest elevation (Cehennemdere) had the lowest germination performance at all water potentials, and stratified and nonstratified seeds from a coastal elevation (Silifke) had the highest germination parameters at the lowest water potential (-0.4 MPa). It might be concluded that seed germination and resistance to water stress vary according to provenance and stratification.

  16. Shifts of heat availability and stressful temperatures in Russian Federation result in gains and losses of wheat thermal suitability

    Science.gov (United States)

    Di Paola, Arianna; Caporaso, Luca; Santini, Monia; Di Paola, Francesco; Vasenev, Ivan; Valentini, Riccardo

    2017-04-01

    Climate changes are likely to shift the suitability of lands devoted to cropping systems. We explored the past-to-future thermal suitability of Russian Federation for wheat (Triticum aestivum) culture through an ensemble of bias corrected CMIP5-GCMs outputs considering two representative concentration pathways (RCP 4.5 and 8.5). Thermal suitability assesses where wheat heat requirement, counted from suggested sowing dates, is satisfied without the occurrence of stressful hot and frost temperatures. Thermal requirement was estimated by means of phenological observations on soft wheat involving different wheat cultivar collected in different regions of Russian Federation, Azerbaidhan, Kazakhstan and Tadzhikistan, whilst stressful temperatures were taken from a literature survey. Results showed projected geographical shift of heat resource toward the north-eastern regions, currently mainly covered by forests and croplands, but also an increase of very hot temperatures in the most productive areas of the southern regions. Gains and losses were then quantified and discussed from both agronomical and climatic perspective.

  17. Theoretical Research on Thermal Shock Resistance of Ultra-High Temperature Ceramics Focusing on the Adjustment of Stress Reduction Factor

    Directory of Open Access Journals (Sweden)

    Daining Fang

    2013-02-01

    Full Text Available The thermal shock resistance of ceramics depends on not only the mechanical and thermal properties of materials, but also the external constraint and thermal condition. So, in order to study the actual situation in its service process, a temperature-dependent thermal shock resistance model for ultra-high temperature ceramics considering the effects of the thermal environment and external constraint was established based on the existing theory. The present work mainly focused on the adjustment of the stress reduction factor according to different thermal shock situations. The influences of external constraint on both critical rupture temperature difference and the second thermal shock resistance parameter in either case of rapid heating or cooling conditions had been studied based on this model. The results show the necessity of adjustment of the stress reduction factor in different thermal shock situations and the limitations of the applicable range of the second thermal shock resistance parameter. Furthermore, the model was validated by the finite element method.

  18. Low-Level Burial Grounds Dangerous Waste Permit Application

    International Nuclear Information System (INIS)

    1989-01-01

    The single dangerous waste permit identification number issued to the Hanford Site by the US Environmental Protection Agency and the Washington State Department of Ecology is US Environmental Protection Agency/State Identification Number WA 7890008967. This identification number encompasses a number of waste management units within the Hanford Site. Westinghouse Hanford Company is a major contractor to the US Department of Energy-Richland Operations Office and serves as co-operator of the Low-Level Burial Grounds, the waste management unit addressed by this permit application. The Low-Level Burial Grounds Dangerous Waste Permit Application consists of both a Part A and a Part B Permit Application. The original Part A, submitted in November 1985, identified landfills, retrievable storage units, and reserved areas. An explanation of subsequent Part A revisions is provided at the beginning of the Part A section. The Part B consists of 15 chapters addressing the organization and content of the Part B checklist prepared by the Washington State Department of Ecology

  19. Ancient Item Spoilage Ritual Used in Nomadic Burial Rite

    Directory of Open Access Journals (Sweden)

    Beisenov Arman Z.

    2017-07-01

    Full Text Available The article considers the findings of items in ancient burials which were intentionally spoiled prior to deposition in graves. This tradition was widely spread both in terms of chronology and geography, and therefore cannot be attributed to any individual cultures or regions. The authors present new information on the ritual obtained during an investigation of Borsyk burial mound of the Middle Sarmatian period located in West Kazakhstan. The central grave of barrow 6 contained a heavily damaged bronze cauldron. The grave was looted in antiquity. Individual scattered bones of a human skeleton and minor gold foil adornments from the ceremonial dress of a nobleman were discovered in the grave. The authors suggest that the cauldron was intentionally deformed by the participants of an ancient mortuary and memorial ritual. According to the principal hypothesis concerning the essence of this ritual, spoilage of the items was related to the idea of assign the items with “different” and “transcendent” properties, which resulted from the necessity of burying the owner. Cauldrons played an important role in the life of steppe leaders. The authors assume a sacral nature of the use of cauldrons in the culture of steppe peoples associated with feasts, battles, and sacred hunting. Perhaps, there was a tradition of burying cauldrons together with their owners after spoiling the items in view of the concept of the other world and the role of a heroic leader therein.

  20. Waste migration in shallow burial sites under unsaturated flow conditions

    International Nuclear Information System (INIS)

    Eicholz, G.G.; Whang, J.

    1987-01-01

    Unsaturated conditions prevail in many shallow-land burial sites, both in arid and humid regions. Unless a burial site is allowed to flood and possibly overflow, a realistic assessment of any migration scenario must take into account the conditions of unsaturated flow. These are more difficult to observe and to model, but introduce significant changes into projected rates of waste leaching and waste migration. Column tests have been performed using soils from the Southeastern coastal plain to observe the effects of varying degrees of ''unsaturation'' on the movement of radioactive tracers. The moisture content in the columns was controlled by maintaining various levels of hydrostatic suction on soil columns whose hydrodynamic characteristics had been determined carefully. Tracer tests, employing Cs-137, I-131 and Ba-133 were used to determine migration profiles and to follow their movement down the column for different suction values. A calculational model has been developed for unsaturated flow and seems to match the observations fairly well. It is evident that a full description of migration processes must take into account the reduced migration rates under unsaturated conditions and the hysteresis effects associated with wetting-drying cycles

  1. Genetic research at a fivefold children's burial from medieval Berlin.

    Science.gov (United States)

    Rothe, Jessica; Melisch, Claudia; Powers, Natasha; Geppert, Maria; Zander, Judith; Purps, Josephine; Spors, Birgit; Nagy, Marion

    2015-03-01

    Berlin originated from the two twin cities Berlin and Cölln, which both were founded at the beginning of the 13th century. However the real date of their foundation as well as the origin of the first settlers is still unknown. On the Berlin site the historic city center is still visible in the Nikolaiviertel, but the medieval origin of Cölln disappeared almost completely. In 2007 a large scale excavation, which comprised an area of about 1700m(2) of the historical center of the St. Peters church, recovers the remains of Cölln's first citizens and span a period of 500 years of medieval population. Here we present the first genetic analysis of a fivefold children's burial from excavations in Berlin. The genetic data unveiled next to ancestry and eye color data also the kinship and the gender of the five individuals. Together with the archeological context the new gained information help to shed more light on the possible reasons for this burial. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. The Application of GPR in Florida for Detecting Forensic Burials

    Energy Technology Data Exchange (ETDEWEB)

    S. K. Koppenjan; J. J. Schultz; S. Ono; H. Lee

    2003-01-01

    A study was performed at the University of Florida to measure ground penetrating radar(GPR) performance for detecting forensic burials. In controlled scenarios, 24 burials were constructed with pig cadavers. Two soils were utilized to represent two of the most common soil orders in Florida: an Entisol and an Ultisol. Graves were monitored on a monthly basis for time periods up to 21 months with grid data acquired with pulsed and swept-frequency GPR systems incorporating several different frequency antennas. A small subset of the graves was excavated to assess decomposition and relate to the GPR images during the test. The grave anomalies in the GPR depth profiles became less distinctive over time due to body decomposition and settling of the disturbed soil (backfill) as it compacted. Soil type was a major factor. Grave anomalies became more difficult to recognize over time for deep targets that were within clay. Forensic targets that were in sandy soil were recognized for the duration of this study. Time elapsed imagery will be presented to elucidate the changes, or lack thereof, of grave anomalies over the duration of this study. Further analysis was performed using Synthetic Aperture Radar (SAR) reconstruction of images in 2-D and 3-D.

  3. Low-Level Burial Grounds Dangerous Waste Permit Application

    International Nuclear Information System (INIS)

    1989-01-01

    The single dangerous waste permit identification number issued to the Hanford Site by the US Environmental Protection Agency and the Washington State Department of Ecology is US Environmental Protection Agency/State Identification Number WA 7890008967. This identification number encompasses a number of waste management units within the Hanford Site. Westinghouse Hanford Company is a major contractor to the US Department of Energy-Richland Operations Office and serves as co-operator of the Low-Level Burial Grounds, the waste management unit addressed by this permit application. The Low-Level Burial Grounds Dangerous Waste Permit Application consists of both a Part A and a Part B Permit Application. The original Part A, submitted in November 1985, identified landfills, retrievable storage units, and reserved areas. An explanation of subsequent Part A revisions is provided at the beginning of the Part A section. Part B consists of 15 chapters addressing the organization and content of the Part B checklist prepared by the Washington State Department of Ecology

  4. Shallow land burial of low-level radioactive wastes

    International Nuclear Information System (INIS)

    Ensminger, J.T.; Owen, P.T.; Fore, C.S.

    1977-10-01

    This publication is the first in a series of annotated bibliographies jointly compiled by the staffs of the Ecological Sciences Information Center of the Information Center Complex at Oak Ridge National Laboratory and of Dames and Moore, White Plains, New York. The data file was built to provide information support to Department of Energy researchers in the field of waste disposal and management. The scope of the data base emphasizes studies which deal with the ''old'' Manhattan sites, commercial disposal sites, and the specific parameters which affect the soil and geologic migration of radionuclides. Specialized data fields have been incorporated into the data base to improve the ease and accuracy of locating pertinent references. Specific radionuclides for which data are presented are listed in the ''Measured Radionuclides'' field, and specific parameters which affect the migration of these radionuclides are presented in the ''Measured Parameters'' field. In addition, each document referenced in this bibliography has been assigned a ''relevance'' number to facilitate sorting the documents according to their pertinence to shallow land burial technology. The documents are rated 1, 2, 3, or 4, with 1 indicating direct applicability to shallow land burial technology and 4 indicating that a considerable amount of interpretation is required for the information presented to be applied. The references are arranged by the organization responsible for the research, with lead authors appearing alphabetically within each installation group. Indexes are provided for author, title, geographic location, keywords, subject categories, measured radionuclides, and publication description. 129 abstracted references

  5. Burial increases seed longevity of two Artemisia tridentata (Asteraceae) subspecies.

    Science.gov (United States)

    Wijayratne, Upekala C; Pyke, David A

    2012-03-01

    Seed longevity and persistence in soil seed banks may be especially important for population persistence in ecosystems where opportunities for seedling establishment and disturbance are unpredictable. The fire regime, an important driver of population dynamics in sagebrush steppe ecosystems, has been altered by exotic annual grass invasion. Soil seed banks may play an active role in postfire recovery of the foundation shrub Artemisia tridentata, yet conditions under which seeds persist are largely unknown. We investigated seed longevity of two Artemisia tridentata subspecies in situ by retrieving seed bags that were placed at varying depths over a 2 yr period. We also sampled naturally dispersed seeds in litter and soil immediately after seed dispersal and before flowering in subsequent seasons to estimate seed persistence. After 24 mo, seeds buried at least 3 cm below the soil surface retained 30-40% viability whereas viability of seeds on the surface and under litter declined to 0 and seeds in the seed bank was highly heterogeneous both spatially and temporally, and attrition varied significantly by region. Our study suggests that Artemisia tridentata has the potential to form a short-term soil seed bank that persists longer than has been commonly assumed, and that burial is necessary for seed longevity. Use of seeding techniques that promote burial of some seeds to aid in formation of a soil seed bank may increase restoration potential.

  6. Ecology and evolution of the diaspore "burial syndrome".

    Science.gov (United States)

    Humphreys, Aelys M; Antonelli, Alexandre; Pirie, Michael D; Linder, H Peter

    2011-04-01

    Hygroscopically active awns or "bristles" have long intrigued scientists. Experimental evidence shows that they are important for diaspore burial in the correct orientation, thereby increasing successful seed germination and seedling survival. Despite these ecological advantages, 38 of the 280 species of grasses in Danthonioideae lack awns. We provide the first study of awns in a phylogenetic context and show that although the awnless state has arisen ca. 25 times independently, the ecological disadvantage of not having an awn also applies in an evolutionary context. Only in Tribolium and Schismus have awnless ancestors diversified to form a clade of primarily awnless descendents. Several of the awnless species in these genera are annual and we find a significant correlation between the evolution of awns and the evolution of life history. A suite of other diaspore traits accompany the awned or awnless states. We interpret the awn as being the visible constituent of a compound "burial syndrome," the two ecological extremes of which may explain the correlation between awns and life history and provide an explanation why awnless species in Tribolium and Schismus persist. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

  7. Physical modelling of globe and natural wet bulb temperatures to predict WBGT heat stress index in outdoor environments.

    Science.gov (United States)

    Gaspar, Adélio R; Quintela, Divo A

    2009-05-01

    The present paper describes a physical model that estimates the globe and the natural wet bulb temperatures from the main parameters generally recorded at meteorological weather stations, in order to predict the wet bulb globe temperature (WBGT) heat stress index for outdoor environments. The model is supported by a thermal analysis of the globe and the natural wet bulb temperature sensors. The results of simultaneous measurements of the WBGT and climatological parameters (solar radiation, wind velocity, humidity, etc.) are presented and used to validate the model. The final comparison between calculated and measured values shows a good agreement with the experimental data, with a maximum absolute deviation of 2.8% for the globe temperature and 2.6% for the natural wet bulb temperature and the WBGT index. The model is applied to the design reference year for Coimbra, Portugal, in order to illustrate its preventative capabilities from a practical point of view. The results clearly show that during the summer there is a critical daily period (1200-1600 hours, local standard time) during which people working outdoors should not be allowed to perform their normal activities.

  8. De novo transcriptome sequencing and comparative analysis of differentially expressed genes in dryoperis fragrans under temperature stress

    International Nuclear Information System (INIS)

    Wang, W.Z.; Tong, W.S.; Gao, R.

    2016-01-01

    Dryopteris fragrans is a species of fern and contains flavonoids compounds with medicinal value. This study explain the temperature stress impact flavonoids synthesis in D. fragrans tissue culture seedlings under the low temperature at 4 degree C, high temperature at 35 degree C and moderate temperature at 25 degree C. By using Illumina HiSeq 2000 sequencing, 80.9 million raw sequence reads were de novo assembled into 66,716 non-redundant unigenes. 38,486 unigenes (57.7%) were annotated for their function. 13,973 unigenes and 29,598 unigenes were allocated to gene ontology (GO) and clusters of orthologous group (COG), respectively. 18,989 sequences mapped to 118 Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG), 204 genes were involved in flavonoid biosynthesis, regulation and transport. 25,292 and 16,817 unigenes exhibited marked differential expression in response to temperature shifts of 25 degree C to 4 degree C and 25 degree C to 35 degree C, respectively. 4CL and CHS genes involved in flavonoid biosynthesis were tested and suggested that they were responsible for biosynthesis of flavonoids. This study provides the first published data to describe the D. fragrans transcriptome and should accelerate understanding of flavonoids biosynthesis, regulation and transport mechanisms. Since most unigenes described here were successfully annotated, these results should facilitate future functional genomic understanding and research of D. fragrans. (author)

  9. Stress corrosion cracking behaviour of low alloy steels in high temperature water: Description and results from modelling

    International Nuclear Information System (INIS)

    Tirbonod, B.

    2001-01-01

    The initiation and growth of a crack by stress and corrosion in the low alloy steels used for the pressure vessels of Boiling Water Reactors may affect the availability and safety of the plant. This paper presents a new model for stress corrosion cracking of the low alloy steels in high temperature water. The model, based on observations, assumes the crack growth mechanism to be based on an anodic dissolution and cleavage. The main results deal with the position of the dissolution cell found at the crack tip, and with the identification of the parameters sensitive to crack growth, among which are the electrolyte composition and the cleavage length. The model is conservative, in qualitative agreement with measurements conducted at PSI, and may be extended to other metal-environment systems. (author)

  10. Genotypic response of detached leaves versus intact plants for chlorophyll fluorescence parameters under high temperature stress in wheat

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Fernández, Juan Olivares; Rosenqvist, Eva

    2014-01-01

    The genotypic response of wheat cultivars as affected by two methods of heat stress treatment (treatment of intact plants in growth chambers versus treatment of detached leaves in test tubes) in a temperature controlled water bath were compared to investigate how such different methods of heat....... The responses of the same cultivars to heat stress were compared between the two methods of heat treatment. The results showed that in detached leaves, all of the fluorescence parameters remained almost unaffected in control (20°C at all durations tested), indicating that the detachment itself did not affect...... variation that can be ascribed to the genetic differences among cultivars for a trait was estimated as genetic determination. During heat treatment, the genetic determination of most of the fluorescence parameters was lower in detached leaves than in intact plants. In addition, the correlation...

  11. Influence of cycle conditions on the creep-rupture behaviour of some creep-resistant steels under variable stress or temperature

    International Nuclear Information System (INIS)

    Kloos, K.H.; Granacher, J.; Abelt, E.

    1978-01-01

    Creep-rupture test lasting up to 20 000h under variable stress or temperature on six creep-resistant steels for power stations. Range of validity of the linear damage accumulation rule to predict time to rupture considering the parameters of the rectangular cycle. Creep-rupture tests show that the mean relative life is influenced by the individual cycle parameters and the type of steel. At beginning basic condition in the cycle and about 3 to 30 cycles to rupture, the mean relative life for all six steels under variable stress amounting to about 63% is shorter than that under variable temperature amounting to about 87%. Peak time proportion and stress change have under variable stress a very much stronger influence than under variable temperature. Beginning peak condition seems to lead according to the first results to additional reduction of life, and this to a larger extent under variable temperature. (orig.) [de

  12. Characterisation of the transcriptomes of genetically diverse Listeria monocytogenes exposed to hyperosmotic and low temperature conditions reveal global stress-adaptation mechanisms.

    Directory of Open Access Journals (Sweden)

    Juliana Durack

    Full Text Available The ability of Listeria monocytogenes to adapt to various food and food- processing environments has been attributed to its robustness, persistence and prevalence in the food supply chain. To improve the present understanding of molecular mechanisms involved in hyperosmotic and low-temperature stress adaptation of L. monocytogenes, we undertook transcriptomics analysis on three strains adapted to sub-lethal levels of these stress stimuli and assessed functional gene response. Adaptation to hyperosmotic and cold-temperature stress has revealed many parallels in terms of gene expression profiles in strains possessing different levels of stress tolerance. Gene sets associated with ribosomes and translation, transcription, cell division as well as fatty acid biosynthesis and peptide transport showed activation in cells adapted to either cold or hyperosmotic stress. Repression of genes associated with carbohydrate metabolism and transport as well as flagella was evident in stressed cells, likely linked to activation of CodY regulon and consequential cellular energy conservation.

  13. Synergistic Effects of Stress-Rupture and Cyclic Loading on Strain Response of Fiber-Reinforced Ceramic-Matrix Composites at Elevated Temperature in Oxidizing Atmosphere

    Directory of Open Access Journals (Sweden)

    Longbiao Li

    2017-02-01

    Full Text Available In this paper, the synergistic effects of stress rupture and cyclic loading on the strain response of fiber-reinforced ceramic-matrix composites (CMCs at elevated temperature in air have been investigated. The stress-strain relationships considering interface wear and interface oxidation in the interface debonded region under stress rupture and cyclic loading have been developed to establish the relationship between the peak strain, the interface debonded length, the interface oxidation length and the interface slip lengths. The effects of the stress rupture time, stress levels, matrix crack spacing, fiber volume fraction and oxidation temperature on the peak strain and the interface slip lengths have been investigated. The experimental fatigue hysteresis loops, interface slip lengths, peak strain and interface oxidation length of cross-ply SiC/MAS (magnesium alumino-silicate, MAS composite under cyclic fatigue and stress rupture at 566 and 1093 °C in air have been predicted.

  14. Comparative miRNAs analysis of Two contrasting broccoli inbred lines with divergent head-forming capacity under temperature stress.

    Science.gov (United States)

    Chen, Chi-Chien; Fu, Shih-Feng; Norikazu, Monma; Yang, Yau-Wen; Liu, Yu-Ju; Ikeo, Kazuho; Gojobori, Takashi; Huang, Hao-Jen

    2015-12-01

    MicroRNAs (miRNAs) play a vital role in growth, development, and stress response at the post-transcriptional level. Broccoli (Brassica oleracea L. var italic) is an important vegetable crop, and the yield and quality of broccoli are decreased by heat stress. The broccoli inbred lines that are capable of producing head at high temperature in summer are unique varieties in Taiwan. However, knowledge of miRNAomes during the broccoli head formation under heat stress is limited. In this study, molecular characterization of two nearly isogenic lines with contrasting head-forming capacity was investigated. Head-forming capacity was better for heat-tolerant (HT) than heat-sensitive (HS) broccoli under heat stress. By deep sequencing and computational analysis, 20 known miRNAs showed significant differential expression between HT and HS genotypes. According to the criteria for annotation of new miRNAs, 24 novel miRNA sequences with differential expression between the two genotypes were identified. To gain insight into functional significance, 213 unique potential targets of these 44 differentially expressed miRNAs were predicted. These targets were implicated in shoot apical development, phase change, response to temperature stimulus, hormone and energy metabolism. The head-forming capacity of the unique HT line was related to autonomous regulation of Bo-FT genes and less expression level of heat shock protein genes as compared to HS. For the genotypic comparison, a set of miRNAs and their targets had consistent expression patterns in various HT genotypes. This large-scale characterization of broccoli miRNAs and their potential targets is to unravel the regulatory roles of miRNAs underlying heat-tolerant head-forming capacity.

  15. Ripening, storage temperature, ethylene action, and oxidative stress alter apple peel phytosterol metabolism

    Science.gov (United States)

    The chilling conditions of apple cold storage can provoke an economically significant necrotic peel disorder called superficial scald (scald) in susceptible cultivars. Disorder development can be reduced by inhibiting ethylene action or oxidative stress. We found previously that scald is preceded b...