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Sample records for stresses exceeding yield

  1. Yield stress fluids slowly yield to analysis

    NARCIS (Netherlands)

    Bonn, D.; Denn, M.M.

    2009-01-01

    We are surrounded in everyday life by yield stress fluids: materials that behave as solids under small stresses but flow like liquids beyond a critical stress. For example, paint must flow under the brush, but remain fixed in a vertical film despite the force of gravity. Food products (such as

  2. Yielding to stress: Recent developments in viscoplastic fluid mechanics

    OpenAIRE

    BALMFORTH, Neil; FRIGAARD, Ian A.; OVARLEZ, Guillaume

    2014-01-01

    The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid. Such behavior characterizes materials common in industries such as petroleum and chemical processing, cosmetics, and food processing and in geophysical fluid dynamics. The most common idealization of a viscoplastic fluid is the Bingham model, which has been widely used to rationalize e...

  3. Yield stress determination of a physical gel

    DEFF Research Database (Denmark)

    Hvidt, Søren

    2013-01-01

    Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresses...... values of these gels depend on test type and measurement time, and no absolute yield stress value can be determined for these physical gels....

  4. Yield stress of alumina-zirconia suspensions

    International Nuclear Information System (INIS)

    Ramakrishnan, V.; Pradip; Malghan, S.G.

    1996-01-01

    The yield stress of concentrated suspensions of alumina, zirconia, and mixed alumina-zirconia powders was measured by the vane technique as a function of solids loading, relative amounts of alumina and zirconia, and pH. At the isoelectric point (IEP), the yield stress varied as the fourth power of the solids loading. The relative ratio of alumina and zirconia particles was important in determining the yield stress of the suspension at the IEP. The yield stress of single and mixed suspensions showed a marked variation with pH. The maximum value occurred at or near the IEP of the suspension. The effect of electrical double-layer forces on the yield stress can be described on the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. A normalized yield stress--that is, the ratio of the yield stress at a given pH to the yield stress at the IEP predicted by this model--showed good correlation with experimental data

  5. On the yield stress of complex materials

    Science.gov (United States)

    Calderas, F.; Herrera-Valencia, E. E.; Sanchez-Solis, A.; Manero, O.; Medina-Torres, L.; Renteria, A.; Sanchez-Olivares, G.

    2013-11-01

    In the present work, the yield stress of complex materials is analyzed and modeled using the Bautista-Manero-Puig (BMP) constitutive equation, consisting of the upper-convected Maxwell equation coupled to a kinetic equation to account for the breakdown and reformation of the fluid structure. BMP model predictions for a complex fluid in different flow situations are analyzed and compared with yield stress predictions of other rheological models, and with experiments on fluids that exhibit yield stresses. It is shown that one of the main features of the BMP model is that it predicts a real yield stress (elastic solid or Hookean behavior) as one of the material parameters, the zero shear-rate fluidity, is zero. In addition, the transition to fluid-like behavior is continuous, as opposed to predictions of more empirical models.

  6. Yield stress independent column buckling curves

    DEFF Research Database (Denmark)

    Stan, Tudor‐Cristian; Jönsson, Jeppe

    2017-01-01

    of the yield stress is to some inadequate degree taken into account in the Eurocode by specifying that steel grades of S460 and higher all belong to a common set of “raised” buckling curves. This is not satisfying as it can be shown theoretically that the current Eurocode formulation misses an epsilon factor......Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...... in the definition of the normalised imperfection magnitudes. By introducing this factor it seems that the GMNIA analysis and knowledge of the independency of residual stress levels on the yield stress can be brought together and give results showing consistency between numerical modelling and a simple modified...

  7. Understanding the rheology of yield stress materials

    NARCIS (Netherlands)

    Paredes Rojas, J.F.

    2013-01-01

    This thesis presents the PhD research on the flow behavior of yield stress materials, using rheological measurements and confocal laser scanning microscopy. Experiments are performed in dispersed systems, such as emulsions, gels and foams; for these, when the amount of the dispersed phase is high

  8. Modified stress intensity factor as a crack growth parameter applicable under large scale yielding conditions

    International Nuclear Information System (INIS)

    Yasuoka, Tetsuo; Mizutani, Yoshihiro; Todoroki, Akira

    2014-01-01

    the modified stress intensity factor can be applied even when the yielding scale exceeds the small-scale yielding criterion. (author)

  9. Yielding to Stress: Recent Developments in Viscoplastic Fluid Mechanics

    Science.gov (United States)

    Balmforth, Neil J.; Frigaard, Ian A.; Ovarlez, Guillaume

    2014-01-01

    The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid. Such behavior characterizes materials common in industries such as petroleum and chemical processing, cosmetics, and food processing and in geophysical fluid dynamics. The most common idealization of a viscoplastic fluid is the Bingham model, which has been widely used to rationalize experimental data, even though it is a crude oversimplification of true rheological behavior. The popularity of the model is in its apparent simplicity. Despite this, the sudden transition between solid-like behavior and flow introduces significant complications into the dynamics, which, as a result, has resisted much analysis. Over recent decades, theoretical developments, both analytical and computational, have provided a better understanding of the effect of the yield stress. Simultaneously, greater insight into the material behavior of real fluids has been afforded by advances in rheometry. These developments have primed us for a better understanding of the various applications in the natural and engineering sciences.

  10. A Study of the Failure Wave Phenomenon in Glasses at Peak Stresses Exceeding the HEL

    International Nuclear Information System (INIS)

    Kanel, G. I.; Razorenov, S. V.; Savinykh, A. S.; Rajendran, A.; Chen Zhen

    2006-01-01

    Shock-wave experiments with two glasses of different hardness have been carried out at shock stress levels above the Hugoniot elastic limit. A comparison between the measured free surface velocity histories from two plate impact experiments performed at approximately the same shock stress level (one with a single thick target plate, and the other with several adjacent target plates of total thickness equal to that of the thick target plate) revealed: 1) at shock loading the failure wave is not formed at stress levels above the HEL, indicating suppression of the fracture process by plasticity, 2) at gradual compression the failure wave process occurs as the stress increases above the failure threshold up to the stress at which plastic deformation begins

  11. The effects of green infrastructure on exceedance of critical shear stress in Blunn Creek watershed

    Science.gov (United States)

    Shannak, Sa'd.

    2017-10-01

    Green infrastructure (GI) has attracted city planners and watershed management professional as a new approach to control urban stormwater runoff. Several regulatory enforcements of GI implementation created an urgent need for quantitative information on GI practice effectiveness, namely for sediment and stream erosion. This study aims at investigating the capability and performance of GI in reducing stream bank erosion in the Blackland Prairie ecosystem. To achieve the goal of this study, we developed a methodology to represent two types of GI (bioretention and permeable pavement) into the Soil Water Assessment Tool, we also evaluated the shear stress and excess shear stress for stream flows in conjunction with different levels of adoption of GI, and estimated potential stream bank erosion for different median soil particle sizes using real and design storms. The results provided various configurations of GI schemes in reducing the negative impact of urban stormwater runoff on stream banks. Results showed that combining permeable pavement and bioretention resulted in the greatest reduction in runoff volumes, peak flows, and excess shear stress under both real and design storms. Bioretention as a stand-alone resulted in the second greatest reduction, while the installation of detention pond only had the least reduction percentages. Lastly, results showed that the soil particle with median diameter equals to 64 mm (small cobbles) had the least excess shear stress across all design storms, while 0.5 mm (medium sand) soil particle size had the largest magnitude of excess shear stress. The current study provides several insights into a watershed scale for GI planning and watershed management to effectively reduce the negative impact of urban stormwater runoff and control streambank erosion.

  12. Analysis of heat stress in UK dairy cattle and impact on milk yields

    International Nuclear Information System (INIS)

    Dunn, Robert J H; Mead, Naomi E; Willett, Kate M; Parker, David E

    2014-01-01

    Much as humans suffer from heat-stress during periods of high temperature and humidity, so do dairy cattle. Using a temperature-humidity index (THI), we investigate the effect of past heatwaves in the UK on heat-stress in dairy herds. Daily THI data derived from routine meteorological observations show that during the summer, there has been an average of typically 1 day per year per station over the past 40 years when the THI has exceeded the threshold for the onset of mild heat-stress in dairy cattle. However, during the heatwaves of 2003 and 2006, this threshold was exceeded on typically 5 days on average in the Midlands, south and east of England. Most dairy cattle are in the west and north of the country and so did not experience the severest heat. Milk yield data in the south-west of England show that a few herds experienced decreases in yields during 2003 and 2006. We used the 11-member regional climate model ensemble with the A1B scenario from UKCP09 to investigate the possible future change in days exceeding the THI threshold for the onset of mild heat-stress. The number of days where the THI exceeds this threshold could increase to over 20 days yr −1 in southern parts of England by the end of the century. (letters)

  13. Analysis of the static yield stress for giant electrorheological fluids

    Science.gov (United States)

    Seo, Youngwook P.; Choi, Hyoung Jin; Seo, Yongsok

    2017-08-01

    Cheng et al. (2010)'s experimental results for the static yield stress of giant electrorheological (GER) fluids over the full range of electric field strengths were reanalyzed by applying Seo's scaling function which could include both the polarization and the conductivity models. The Seo's scaling function could correctly fit the yield stress behavior of GER suspensions behavior after if a proper normalization of the yield stress data was taken which collapse them onto a single curve. The model predictions were also contrasted with recently proposed Choi et al.'s scaling function to rouse the attention for a proper consideration of the GER fluid mechanisms.

  14. Effect of water stress on yield and yield components of sunflower ...

    African Journals Online (AJOL)

    A field experiment during year 2009 was conducted in the research station of the University of Tehran, College of Abouraihan in Pakdasht region, Iran. The study was aimed to investigate the effect of water stress on seed yield, yield component and some quantitative traits of four sunflower hybrids namely Azargol, Alstar, ...

  15. Microstructure, Slip Systems and Yield Stress Anisotropy in Plastic Deformation

    DEFF Research Database (Denmark)

    Winther, Grethe; You, Ze Sheng; Lu, Lei

    The highly anisotropic microstructures in nanotwinned copper produced by electrodeposition provide an excellent opportunity to evaluate models for microstructurally induced mechanical anisotropy. A crystal plasticity model originally developed for the integration of deformation induced dislocatio...... boundaries with texture is applied to account for the effects of texture as well as twin and grain boundaries, providing good qualitative agreement with experimental yield stress and yield stress anisotropy data....

  16. Baseline Goblet Cell Mucin Secretion in the Airways Exceeds Stimulated Secretion over Extended Time Periods, and Is Sensitive to Shear Stress and Intracellular Mucin Stores.

    Directory of Open Access Journals (Sweden)

    Yunxiang Zhu

    Full Text Available Airway mucin secretion studies have focused on goblet cell responses to exogenous agonists almost to the exclusion of baseline mucin secretion (BLMS. In human bronchial epithelial cell cultures (HBECCs, maximal agonist-stimulated secretion exceeds baseline by ~3-fold as measured over hour-long periods, but mucin stores are discharged completely and require 24 h for full restoration. Hence, over 24 h, total baseline exceeds agonist-induced secretion by several-fold. Studies with HBECCs and mouse tracheas showed that BLMS is highly sensitive to mechanical stresses. Harvesting three consecutive 1 h baseline luminal incubations with HBECCs yielded equal rates of BLMS; however, lengthening the middle period to 72 h decreased the respective rate significantly, suggesting a stimulation of BLMS by the gentle washes of HBECC luminal surfaces. BLMS declined exponentially after washing HBECCs (t1/2 = 2.75 h, to rates approaching zero. HBECCs exposed to low perfusion rates exhibited spike-like increases in BLMS when flow was jumped 5-fold: BLMS increased >4 fold, then decreased within 5 min to a stable plateau at 1.5-2-fold over control. Higher flow jumps induced proportionally higher BLMS increases. Inducing mucous hyperplasia in HBECCs increased mucin production, BLMS and agonist-induced secretion. Mouse tracheal BLMS was ~6-fold higher during perfusion, than when flow was stopped. Munc13-2 null mouse tracheas, with their defect of accumulated cellular mucins, exhibited similar BLMS as WT, contrary to predictions of lower values. Graded mucous metaplasia induced in WT and Munc13-2 null tracheas with IL-13, caused proportional increases in BLMS, suggesting that naïve Munc13-2 mouse BLMS is elevated by increased mucin stores. We conclude that BLMS is, [i] a major component of mucin secretion in the lung, [ii] sustained by the mechanical activity of a dynamic lung, [iii] proportional to levels of mucin stores, and [iv] regulated differentially from agonist

  17. Baseline Goblet Cell Mucin Secretion in the Airways Exceeds Stimulated Secretion over Extended Time Periods, and Is Sensitive to Shear Stress and Intracellular Mucin Stores

    Science.gov (United States)

    Doyle, Sean P.; Nguyen, Kristine; Ribeiro, Carla M. P.; Vasquez, Paula A.; Forest, M. Gregory; Lethem, Michael I.; Dickey, Burton F.; Davis, C. William

    2015-01-01

    Airway mucin secretion studies have focused on goblet cell responses to exogenous agonists almost to the exclusion of baseline mucin secretion (BLMS). In human bronchial epithelial cell cultures (HBECCs), maximal agonist-stimulated secretion exceeds baseline by ~3-fold as measured over hour-long periods, but mucin stores are discharged completely and require 24 h for full restoration. Hence, over 24 h, total baseline exceeds agonist-induced secretion by several-fold. Studies with HBECCs and mouse tracheas showed that BLMS is highly sensitive to mechanical stresses. Harvesting three consecutive 1 h baseline luminal incubations with HBECCs yielded equal rates of BLMS; however, lengthening the middle period to 72 h decreased the respective rate significantly, suggesting a stimulation of BLMS by the gentle washes of HBECC luminal surfaces. BLMS declined exponentially after washing HBECCs (t1/2 = 2.75 h), to rates approaching zero. HBECCs exposed to low perfusion rates exhibited spike-like increases in BLMS when flow was jumped 5-fold: BLMS increased >4 fold, then decreased within 5 min to a stable plateau at 1.5–2-fold over control. Higher flow jumps induced proportionally higher BLMS increases. Inducing mucous hyperplasia in HBECCs increased mucin production, BLMS and agonist-induced secretion. Mouse tracheal BLMS was ~6-fold higher during perfusion, than when flow was stopped. Munc13-2 null mouse tracheas, with their defect of accumulated cellular mucins, exhibited similar BLMS as WT, contrary to predictions of lower values. Graded mucous metaplasia induced in WT and Munc13-2 null tracheas with IL-13, caused proportional increases in BLMS, suggesting that naïve Munc13-2 mouse BLMS is elevated by increased mucin stores. We conclude that BLMS is, [i] a major component of mucin secretion in the lung, [ii] sustained by the mechanical activity of a dynamic lung, [iii] proportional to levels of mucin stores, and [iv] regulated differentially from agonist-induced mucin

  18. Local yield stress statistics in model amorphous solids

    Science.gov (United States)

    Barbot, Armand; Lerbinger, Matthias; Hernandez-Garcia, Anier; García-García, Reinaldo; Falk, Michael L.; Vandembroucq, Damien; Patinet, Sylvain

    2018-03-01

    We develop and extend a method presented by Patinet, Vandembroucq, and Falk [Phys. Rev. Lett. 117, 045501 (2016), 10.1103/PhysRevLett.117.045501] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a nonperturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process.

  19. Relation between academic yield and stress in medical students

    Directory of Open Access Journals (Sweden)

    Sandra Patricia González Peña

    2006-12-01

    Full Text Available Objective. To study risk factors that where found as influence in the academic yield (stress, alcohol, friendships, depression and family relations in the students of the Medicine Faculty of the Universidad de Manizales. Materials and methods: Descriptive study integrated by random selected sample, who were attending of II to XI semester of the Medicine faculty. An anonymous survey was conduced about sociodemographic, cultural, academic and motivational characteristics,including stress, depresión, family disfunction and substance abuse. We correlated all variables with academic yield using chi square test, Pearson`s coefficient and lineal regression. Results: 212 students of ages between 17 and 31 years where analyzed, in which the majority where from another city. Some of the factors were detected which affect the academic yield of the students as it is stress, depression, the family function and friendships among others. Conclusions: A significant relation between academic yield and stress was found. In turn, stress variable was influenced by depression, alcohol and family relation.

  20. Effects of Drought Stress on Canola (Brassica napus L. Genotypes Yield and Yield Components

    Directory of Open Access Journals (Sweden)

    R Khani

    2018-02-01

    Full Text Available Introduction Canola (Brassica napus L. genotypes with wide adaptability to environmental conditions could play a major role in Iran’s oilseed crop production. Selection of high performing genotypes is very important for developing canola cultivation. Water stress can reduce crop yield by affecting both source and sink for assimilation. Canola yield depends on genotype and environmental conditions and response of genotypes to environmental factors. Canola genotypes response to stress depends on the developmental stage and the events occurring prior to and during flowering stage. Resistance to water stress is divided to avoidance and tolerance. Some species are tolerable against water stress. In a while, other species respond ending life cycle, falling leaves and other reactions into water stress. Therefore, investigation of canola genotypes response to water stress in phenological growth stages can be valuable in order to determine resistant or tolerant genotypes. Materials and Methods In order to study the effect of drought stress on canola genotypes yield and its components, an experiment was conducted in 2013-2014 as a split plot based on randomized complete block design with three replications at the research farm, Agricultural and Natural Resources Research Center of East-Azarbaijan, Tabriz-Iran. Three levels of drought stress were considered as main plot (No-stress, stress at the flowering and pod setting growth stages and 18 canola genotypes including HW113, RS12, Karaj1, KR18, L73, L72, HW101, L146, L210, L183, SW101, L5, L201, HW118, KR4, Karaj2, Karaj3 and KS7 as subplots. Flood irrigation was scheduled at 50% field capacity, 30 and 30% field capacity for no-stress, stress at the flowering and pod setting growth stages, respectively; i.e. soil moisture capacity was maintained at 30% by irrigating to 100% field capacity when available moisture reached 30% in drought stress treatments. An ANOVA was conducted using the PROC-GLM procedure

  1. Metastability at the Yield-Stress Transition in Soft Glasses

    Science.gov (United States)

    Lulli, Matteo; Benzi, Roberto; Sbragaglia, Mauro

    2018-04-01

    We study the solid-to-liquid transition in a two-dimensional fully periodic soft-glassy model with an imposed spatially heterogeneous stress. The model we consider consists of droplets of a dispersed phase jammed together in a continuous phase. When the peak value of the stress gets close to the yield stress of the material, we find that the whole system intermittently tunnels to a metastable "fluidized" state, which relaxes back to a metastable "solid" state by means of an elastic-wave dissipation. This macroscopic scenario is studied through the microscopic displacement field of the droplets, whose time statistics displays a remarkable bimodality. Metastability is rooted in the existence, in a given stress range, of two distinct stable rheological branches, as well as long-range correlations (e.g., large dynamic heterogeneity) developed in the system. Finally, we show that a similar behavior holds for a pressure-driven flow, thus suggesting possible experimental tests.

  2. Predicted strains in austenitic stainless steels at stresses above yield

    International Nuclear Information System (INIS)

    Hammond, J.P.; Sikka, V.K.

    1977-01-01

    Tensile results on austenitic stainless steels were analyzed to develop means for predicting strains at stresses above yield for reactor regulatory applications. Eight heats each of types 316 and 304 were tested at 24, 93, 204, and 316 0 C as mill-annealed and at 24 0 C after reannealing. The effects of heat-to-heat variations on total strain (to 5%) at discrete stress levels were portrayed by a rational polynomial incorporating three constants that relate to the basic features of the true-stress-true-strain diagram. Because these constants usually are interrelated, a single parameter, yield strength (YS), proved adequate to predict results. For predictions analytical expressions of yield strength, an average value (YSa), and a lower bound value [YSa - 1.65SEE (standard error of estimate)] were used. Using the rational polynomial with these parameters we determined (1) limits of total maximum strain and (2) ratios of strain of material of lower bound YS to that of average YS. These are recorded at regular increments of stress [34 MPa (5 ksi)] and at ASME Code-related stresses (S/sub y), S/sub m/, 1.2S/sub m/ and 1.5S/sub m/). At intermediate stresses, strain penalties for using material of lower bound strength were large, generally larger for type 316 than type 304. For mill-annealed type 316 at 24, 93, 204, and 316 0 C, the maximum ratios of strain were 8.8, 13.0, 14.1, and 14.9, respectively, whereas for type 304 they were 3.5, 3.4, 5.6, and 4.6. At 1.5S/sub m/ and 316 0 C, a maximum strain of 2.08% was predicted for type 316 and 1.66% for type 304, as contrasted to values of 0.14 and 0.39% for average strain

  3. Yield stress determination from miniaturized disk bend test data

    International Nuclear Information System (INIS)

    Sohn, D.S.; Kohse, G.; Harling, O.K.

    1985-04-01

    Methodology for testing 3.0 mm diameter by 0.25 mm thick disks by bending in a punch and die has been described previously. This paper describes the analysis of load/deflection data from such miniaturized disk bend tests (MDBT) using a finite element simulation. Good simulation has been achieved up to a point just beyond the predominantly elastic response, linear initial region. The load at which deviation from linearity begins has been found to correlate with yield stress, and yield stress has been successfully extracted from disk bend tests of a number of known materials. Although finite element codes capable of dealing with large strains and large rotations have been used, simulation of the entire load/deflection curve up to fracture of the specimen has not yet been achieved

  4. Evaluating Yield and Drought Stress Indices under End Season Drought Stress in Promising Genotypes of Barley

    Directory of Open Access Journals (Sweden)

    H. Tajalli

    2012-08-01

    Full Text Available To study the effects of end season drought stress on yield, yield components and drought stress indices in barley, a split plot experiment arranged in randomized complete block design with three replications was conducted at the Agricultural Research Center of Birjand in 2008-2009 crop years. Drought stress, in 2 levels, consists of control (complete irrigation and stopping irrigation at the 50% of heading stage, and 20 promising genotypes of barley were the treatments of the experiment. Results revealed that stopping irrigation lead to declining of 14.64 and 8.12 percent of seed and forage yields against control condition, respectively. Using stress susceptibility index (SSI indicated that genotypes 2, 3, 7, 9, 10 and 15; using STI and GMP indices, genotypes 5, 8, 18 and 20 using MP, genotypes 8, 18 and 20, and TOL, genotypes 2, 3, 7, 9, and 10, were the most drought tolerant genotypes. Correlation between seed yield and stress evaluation indices showed that MP, GMP and STI are the best indices to be used in selection and introducing drought tolerant genotypes of barley. Considering all indices, and given that the best genotypes are those with high yield under normal condition and minimum yield reduction under drought stress, No. 18 and 20 could be introduced as the most tolerant barley genotypes to drought.

  5. Effect of Drought Stress at Different Growth Stages on Yield and Yield Components of Six Rice (Oryza sativa L. Genotypes

    Directory of Open Access Journals (Sweden)

    Sharifunnessa Moonmoon

    2017-12-01

    Full Text Available Drought stress affects plant growth and development and ultimately, reduced grain yield of rice. But stress at different growth stages may respond differently which is still unclear. Therefore, a pot experiment was carried out with six rice genotypes to determine the critical growth stage where drought stress effect on yield reduction and to find stress tolerance mechanism in rice genotypes. Drought stress (control i.e. no stress and 40% field capacity, FC was imposed on Binadhan-13, Kalizira, BRRI dhan34, Ukunimodhu, RM-100-16 and NERICA mutant rice genotypes at maximum tillering, panicle initiation and grain filling stages and discontinued when the specific stage was over. The experiment was laid out in a complete randomized design with three replications. Drought stress affected number of effective tiller hill-1, number of spikelets panicle-1, filled grains hill-1, 1000-grain weight and grain yield. Binadhan-13 produced the highest grain yield and the lowest sterility under drought stress at grain filling stage. Percentage of spikelet sterility increased under drought stress (40% FC especially at the panicle initiation stage resulting low grain yield. Among the tested genotypes Binadhan-13 performed well by reducing spikelet sterility under drought stress condition. For 1000-grain weight and grain yield, grain filling stage was found more crucial. From the current research, drought tolerance mechanism was found in genotypes Binadhan-13 and NERICA mutant. [Fundam Appl Agric 2017; 2(3.000: 285-289

  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. Metastability at the Yield-Stress Transition in Soft Glasses

    Directory of Open Access Journals (Sweden)

    Matteo Lulli

    2018-05-01

    Full Text Available We study the solid-to-liquid transition in a two-dimensional fully periodic soft-glassy model with an imposed spatially heterogeneous stress. The model we consider consists of droplets of a dispersed phase jammed together in a continuous phase. When the peak value of the stress gets close to the yield stress of the material, we find that the whole system intermittently tunnels to a metastable “fluidized” state, which relaxes back to a metastable “solid” state by means of an elastic-wave dissipation. This macroscopic scenario is studied through the microscopic displacement field of the droplets, whose time statistics displays a remarkable bimodality. Metastability is rooted in the existence, in a given stress range, of two distinct stable rheological branches, as well as long-range correlations (e.g., large dynamic heterogeneity developed in the system. Finally, we show that a similar behavior holds for a pressure-driven flow, thus suggesting possible experimental tests.

  8. Commercial-scale recycling of NdFeB-type magnets with grain boundary modification yields products with 'designer properties' that exceed those of starting materials.

    Science.gov (United States)

    Zakotnik, M; Tudor, C O

    2015-10-01

    NdFeB-type magnets dominate the market for high performance magnetic materials, yet production of 'virgin' magnets via mining is environmentally, financially and energetically costly. Hence, interest is growing in 'magnet to magnet' recycling schemes that offer the potential for cheaper, more environmentally-friendly solutions to the world's growing appetite for rare-earth based magnetic materials. Unfortunately, previously described recycling processes only partially capitalise on this potential, because the methods described to date are limited to 'laboratory scale' or operate only under ideal conditions and result in products that fail to recapture the coercivity of the starting, scrap materials. Herein, we report a commercial scale process (120 kg batches) that completely recovers the properties of the starting scrap magnets. Indeed, 'grain boundary modification', via careful addition of a proprietary mix of blended elements, produces magnets with 'designer properties' that can exceed those of the starting materials and can be closely tailored to meet a wide variety of end-user applications, including high-coercivity (>2000 kA/m), sintered magnets suitable for motor applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Yield Stress Model for Molten Composition B-3

    Science.gov (United States)

    Davis, Stephen; Zerkle, David

    2017-06-01

    Composition B-3 (Comp B-3) is a melt-castable explosive composed of 60/40 wt% RDX/TNT (hexahydro-1,3,5-trinitro-1,3,5-triazine/2,4,6-trinitrotoluene). During casting operations thermal conditions are controlled which along with the low melting point of TNT and the insensitivity of the mixture to external stimuli leading to safe use. Outside these standard operating conditions a more rigorous model of Comp B-3 rheological properties is necessary to model thermal transport as Comp B-3 evolves from quiescent solid through vaporization/decomposition upon heating. One particular rheological phenomena of interest is Bingham plasticity, where a material behaves as a quiescent solid unless a sufficient load is applied, resulting in fluid flow. In this study falling ball viscometer data is used to model the change in Bingham plastic yield stresses as a function of RDX particle volume fraction; a function of temperature. Results show the yield stress of Comp B-3 (τy) follows the expression τy = B ϕ -ϕc N , where Φ and Φc are the volume fraction of RDX and a critical volume fraction, respectively and B and N are experimentally evaluated constants.

  10. Effect of soil water stress on yield and proline content of four wheat ...

    African Journals Online (AJOL)

    Effect of soil water stress on yield and proline content of four wheat lines. ... This field study was conducted to evaluate the effect of drought stress after anthesis on proline accumulation and wheat yield during 2008 at ... from 32 Countries:.

  11. Yield Stress Reduction of DWPF Melter Feed Slurries

    International Nuclear Information System (INIS)

    Stone, M.E.; Smith, M.E.

    2007-01-01

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides and soluble sodium salts. The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame

  12. On a new method to determine the yield stress in lubricating grease

    NARCIS (Netherlands)

    Cyriac, F.; Lugt, Pieter Martin; Bosman, Rob

    2015-01-01

    An experimental study using both a controlled stress and a controlled strain rheometer has been undertaken to characterize lubricating grease in shear, creep, stress relaxation, and oscillatory flow, with a main focus on determining the yield stress. The yield stress was examined using a cone–plate

  13. The start of ebullition in quiescent, yield-stress fluids

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, David J., E-mail: djsherwo@bechtel.com [URS Corporation, Hanford Tank Waste Treatment and Immobilization Plant Project, 2435 Stevens Center Place, Richland, WA 99354 (United States); Eduardo Sáez, A. [Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721 (United States)

    2014-04-01

    Highlights: • Nuclear waste slurries evolve gases from radiochemical reactions. • Evolved gases form bubbles that rise in the yield-stress slurry. • Bubble buoyancy leads to expansion and ebullition, processes modeled here. - Abstract: Non-Newtonian rheology is typical for the high-level radioactive waste (HLW) slurries to be processed in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hydrogen and other flammable gases are generated in the aqueous phase by radiolytic and chemical reactions. HLW slurries have a capacity for retaining gas characterized by the shear strength holding the bubbles still. The sizes and degassing characteristics of flammable gas bubbles in the HLW slurries, expected to be processed by the WTP are important considerations for designing equipment and operating procedures. Slurries become susceptible to degassing as the bubble concentration increases over a maximum value that depends on shear strength. This susceptibility and the process of ebullitive bubble enlargement are described here. When disturbed, the fluid undergoes localized flow around neighboring bubbles which are dragged together and coalesce, producing an enlarged bubble. For the conditions considered in this work, bubble size increase is enough to displace the weight required to overcome the fluid shear strength and yield the surroundings. The buoyant bubble ascends and accumulates others within a zone of influence, enlarging by a few orders of magnitude. This process describes how the first bubbles appear on the surface of a 7 Pa shear strength fluid a few seconds after being jarred.

  14. Environmental stress in German forests; assessment of critical deposition levels and their exceedances and meteorological stress for crown condition monitoring sites in Germany

    NARCIS (Netherlands)

    Klap, J.M.; Reinds, G.J.; Bleeker, A.; Vries, de W.

    2000-01-01

    Site-specific estimations of meteorological stress and atmospheric deposition were made for the systematic 8 x 8 km2 forest condition monitoring network in Germany for the years 1987-1995. Winter cold and late frost were important temperature stress variables and relative transpiration was a good

  15. Yielding the yield-stress analysis: a study focused on the effects of elasticity on the settling of a single spherical particle in simple yield-stress fluids.

    Science.gov (United States)

    Fraggedakis, D; Dimakopoulos, Y; Tsamopoulos, J

    2016-06-28

    The sedimentation of a single particle in materials that exhibit simultaneously elastic, viscous and plastic behavior is examined in an effort to explain phenomena that contradict the nature of purely yield-stress materials. Such phenomena include the loss of the fore-and-aft symmetry with respect to an isolated settling particle under creeping flow conditions and the appearance of the "negative wake" behind it. Despite the fact that similar observations have been reported in studies involving viscoelastic fluids, researchers conjectured that thixotropy is responsible for these phenomena, as the aging of yield-stress materials is another common feature. By means of transient calculations, we study the effect of elasticity on both the fluidized and the solid phase. The latter is considered to behave as an ideal Hookean solid. The material properties of the model are determined under the isotropic kinematic hardening framework via Large Amplitude Oscillatory Shear (LAOS) measurements. In this way, we are able to predict accurately the unusual phenomena observed in experiments with simple yield-stress materials, irrespective of the appearance of slip on the particle surface. Viscoelasticity favors the formation of intense shear and extensional stresses downstream of the particle, significantly changing the entrapment mechanism in comparison to that observed in viscoplastic fluids. Therefore, the critical conditions under which the entrapment of the particle occurs deviate from the well-known criterion established theoretically by Beris et al. (1985) and verified experimentally by Tabuteau et al. (2007) for similar materials under conditions that elastic effects are negligible. Our predictions are in quantitative agreement with published experimental results by Holenberg et al. (2012) on the loss of the fore-aft symmetry and the formation of the negative wake in Carbopol with well-characterized rheology. Additionally, we propose simple expressions for the Stokes drag

  16. Effects of drought stress condition on the yield of spring wheat ...

    African Journals Online (AJOL)

    Effects of drought stress condition on the yield of spring wheat ( Triticum aestivum ) lines. ... Drought stress tolerance is seen in almost all plants but its extent varies from species to species and even within species. ... from 32 Countries:.

  17. Physiological basis of barley yield under near optimal and stress conditions

    Directory of Open Access Journals (Sweden)

    Pržulj Novo

    2004-01-01

    Full Text Available Average barley yield fall below its potential due to incidence of stresses. Water stress is the main environmental factor limiting yield. The component a priori more sensitive to most stresses is the amount of radiation absorbed. The effect of stresses influence on the total amount of radiation absorbed by barley crop during its vegetation and the photosynthetic efficiency of radiation conversion. Growth inhibition is accompanied by reductions in leaf and cell wall extensibility. Grain yield under drought conditions is source limited. Supply of assimilates to the developing inflorescence plays a critical role in establishing final grain number and grain size. Grain weight is negatively affected by drought, high temperature, and any other factors that may reduce grain filling duration and grain filling rate. Awns and glaucousness confer better performance of barley under drought stress conditions. Barley responds with an increased accumulation of a number of proteins when subjected to different stress inducing cell dehydration. Screening techniques that are able to identify desirable genotypes based on the evaluation of physiological traits related to stress evasion and stress resistance maybe useful in breeding barley for resistance to stress, particularly drought stress. Crop management and breeding can reduce the incidence of stress on yield. The effect of these practices is sustained by an understanding of their physiology. In this paper the physiological basis of the processes determining barley yield and the incidence of stresses on photosynthetic metabolism that determine grain yield of barley is discussed. .

  18. An analytical solution describing the shape of a yield stress material subjected to an overpressure

    DEFF Research Database (Denmark)

    Hovad, Emil; Spangenberg, Jon; Larsen, P.

    2016-01-01

    as well as the spread length and height of the material when deformed in a box due to gravity. In the present work, the analytical solution is extended with the addition of an overpressure that acts over the entire body of the material. This extension enables finding the shape of a yield stress material......Many fluids and granular materials are able to withstand a limited shear stress without flowing. These materials are known as yields stress materials. Previously, an analytical solution was presented to quantify the yield stress for such materials. The yields stress is obtained based on the density...... with known density and yield stress when for instance deformed under water or subjected to a forced air pressure....

  19. Modelling of snow exceedances

    Science.gov (United States)

    Jordanova, Pavlina K.; Sadovský, Zoltán; Stehlík, Milan

    2017-07-01

    Modelling of snow exceedances is of great importance and interest for ecology, civil engineering and general public. We suggest the favorable fit for exceedances related to the exceptional snow loads from Slovakia, assuming that the data is driven by Generalised Pareto Distribution or Generalized Extreme Value Distribution. Further, the statistical dependence between the maximal snow loads and the corresponding altitudes is studied.

  20. Influence of moisture stress on growth, dry matter yield and ...

    African Journals Online (AJOL)

    The effects of moisture stress were evaluated in four Indigofera species (I. amorphoides, I. arrecta, I. coerulea and I. vicioides) using a pot experiment under glasshouse conditions. The aim was to examine the influence of moisture-deficit stress on physiological attributes and performance of the four Indigofera species.

  1. Evaluation of Relationship Between Auxin and Cytokinine Hormones on Yield and Yield Components of Maize under Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    A Mahrokh

    2016-10-01

    Full Text Available Introduction Drought is one of the major environmental conditions that adversely affects plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting crop production worldwide. Drought is the major restriction in maize production. The plant growth reduction under drought stress conditions could be an outcome of altered hormonal balance and hence the exogenous application of growth regulators under stress conditions could be the possible means for reversing the effects of abiotic stress. Phytohormones such as auxine and cytokinine are known to be involved in the regulation of plant response to the adverse effects of stress conditions. Previous studies have shown that endogenous hormones are essential regulators for translocation and partitioning of photoassimilates for grain filling in cereal crops, and therefore could be involved in the regulation of grain weight and yield. Materials and Methods The experiment was carried out in three separately environments included non-drought stress environment (irrigation after soil moisture reached to 75% field capacity, drought stress in vegetative stage (irrigation after soil moisture reached to 50% field capacity in V4 to tasseling stage, but irrigation after soil moisture reached to 75% field capacity in pollination to physiological maturity stage and drought stress in reproductive stage (irrigation after soil moisture reached to 75% field capacity in V4 to tasseling stage and irrigation after soil moisture reached to 50% field capacity in pollination to physiological maturity stage. Cytokinin hormone in three levels (control, spraying in V5 –V6 and V8-V10 stages and auxin hormone in three levels (control, spraying in silk emergence stage and 15 days after that were laid out as a factorial design based on randomized complete block with three replications in each environment at Seed and Plant Improvement Institute (SPII

  2. Effect of moisture stress and low phosphorus on yield of some ...

    African Journals Online (AJOL)

    Soybean genotypes belonging to different maturity periods were planted under normal, nutrient (P) and moisture stress conditions in a combined design with three replications. The objective was to determine the effect of phosphorus and moisture stress on yield and yield components of soybean in order to select varieties ...

  3. Characterizing drought stress and trait influence on maize yield under current and future conditions.

    Science.gov (United States)

    Harrison, Matthew T; Tardieu, François; Dong, Zhanshan; Messina, Carlos D; Hammer, Graeme L

    2014-03-01

    Global climate change is predicted to increase temperatures, alter geographical patterns of rainfall and increase the frequency of extreme climatic events. Such changes are likely to alter the timing and magnitude of drought stresses experienced by crops. This study used new developments in the classification of crop water stress to first characterize the typology and frequency of drought-stress patterns experienced by European maize crops and their associated distributions of grain yield, and second determine the influence of the breeding traits anthesis-silking synchrony, maturity and kernel number on yield in different drought-stress scenarios, under current and future climates. Under historical conditions, a low-stress scenario occurred most frequently (ca. 40%), and three other stress types exposing crops to late-season stresses each occurred in ca. 20% of cases. A key revelation shown was that the four patterns will also be the most dominant stress patterns under 2050 conditions. Future frequencies of low drought stress were reduced by ca. 15%, and those of severe water deficit during grain filling increased from 18% to 25%. Despite this, effects of elevated CO2 on crop growth moderated detrimental effects of climate change on yield. Increasing anthesis-silking synchrony had the greatest effect on yield in low drought-stress seasonal patterns, whereas earlier maturity had the greatest effect in crops exposed to severe early-terminal drought stress. Segregating drought-stress patterns into key groups allowed greater insight into the effects of trait perturbation on crop yield under different weather conditions. We demonstrate that for crops exposed to the same drought-stress pattern, trait perturbation under current climates will have a similar impact on yield as that expected in future, even though the frequencies of severe drought stress will increase in future. These results have important ramifications for breeding of maize and have implications for

  4. Evaluation of Chitosan Nanoparticles Effects on Yield and Yield Components of Barley (Hordeum vulgare L. under Late Season Drought Stress

    Directory of Open Access Journals (Sweden)

    Faride Behboudi

    2018-01-01

    Full Text Available As a step towards the profitable employment of nanoparticles (NPs in agriculture, effects of chitosan NPs was probed on barley plants under late season drought stress. A factorial experiment was performed based on a randomized complete block design with three replications. The experimental factors included the chitosan NPs concentrations (0 (control, 30, 60 and 90 ppm, application methods (foliar and soil application and irrigation regimes (well-watered and withholding of irrigation for 15 days after pollination. The barley seeds were separately planted in pots. Then, the NPs were added to them through the soil and foliar application at three stages. The results indicated that using the chitosan NPs, especially 60 and 90 ppm, significantly increased the leaf area (LA, the leaf color (SPAD, the number of grain per spike, the grain yield and the harvest index compared to the control. Also, drought stress significantly decreased the yield and yield components compared to the well-watered plants. In contrast, using the chitosan NPs in plants under drought stress significantly increased the relative water content (RWC, the 1000-grain weight, the grain protein, the proline content, the catalase (CAT and the superoxide dismutase (SOD compared to the control. There was no a significant difference between two methods of using NPs in most studied traits. The results highlighted that using the chitosan NPs, especially 60 and 90 ppm, in both irrigation regimes can significantly improve the majority of the studied traits compared to the control and mitigate the harmful effects of drought stress.

  5. Effect of drought stress on yield, proline and chlorophyll contents in three chickpea cultivars

    NARCIS (Netherlands)

    Mafakheri, A.; Siosemardeh, A.; Bahramnejad, B.; Struik, P.C.; Sohrabi, Y.

    2010-01-01

    Drought stress is one of the major abiotic stresses in agriculture worldwide. This study was carried out to investigate the effect of drought stress on proline content, chlorophyll content, photosynthesis and transpiration, stomatal conductance and yield characteristics in three varieties of

  6. Effects of Methanol Spraying on Qualitative traits, Yield and Yield Components of Soybean (Glycine max L. under Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    J Esazadeh Panjali Kharabasi

    2017-12-01

    Full Text Available Introduction Soybean (Glycin max L. is one of the most important oilseed crops in the world. It can provide oil and vegetable protein suitable for feeding humans as well as animals. The productivity Increasing of this crop in Iran has been the subject of continuous investigation over the past few years. It is well known that adequate water supply is considered as a very important factor to affect the accumulation of dry matter in the plant as well as vegetative growth of most crops. Irrigation is an important factor affecting soybean growth and yield and its related components. Exposing soybean plants to soil moisture stress at any phase of its life cycle may lead to a detrimental effect on growth, yield and its components. The methanol spraying can lead to increase in yield, expediting in maturity and reduction in drought stress impacts and water requirement of crops. Material and Methods The experiment was conducted as split plots based on randomized complete block design with three replications at the Research Farm, Faculty of Agriculture of Moghan, Iran, in 2011. Treatments included three levels of drought stress as follows irrigation after, 40 (control, 55 and 70 percentage of available soil moisture depletion as main plots, and four levels of methanol spraying including 0 (control, 7, 21 and 35 volumetric percentage as sub plots. The studied traits were included plant height, leaf area, number of pod and seed per plant, 1000 seed weight, biological and seed yield, stomatal conductance and proline contents. Statistical analysis was carried out using SAS version 9.1 software. Significant difference was set at p ≤ 0.05 by using Duncan’s multiple range test. Results and Discussion The results showed that the plant height, leaf area, number of pod and seed per plant, 1000 seed weight, biological and seed yield, stomatal conductance and proline contents as well as number of leaf per plant significantly affected by drought stress and methanol

  7. Response of Yield, Yield Components and Nutrient Concentration of Cumin (Cuminum cyminum L. to Mycorrhizal Symbiosis under Salt Stress Conditions

    Directory of Open Access Journals (Sweden)

    M. Bijhani

    2016-01-01

    Full Text Available To study the effects of mycorrhizal inoculation and salinity stress on the growth, yield and nutrient concentrations of cumin (Cuminum cyminum L., an experiment was carried out as split plot in a completely randomized block design at Zabol University Research Farm in 2013. Treatments consisted of three salinity stresses: 1 (control, 5 and 10 dSm-1, was considered as the main treatments, and four levels of mycorrhizal inoculation (Glomus intraradices, G. etanicatum, G. hoi and non-inoculation as control as the sub-treatments. The effects of salinity on all traits under study, except umbers per plant, were significant, and severe stress (10 dSm-1 reduced 100 seed weight, number of seeds per umbel, concentrations of phosphorus, calcium and magnesium in seeds by 17.71, 11.4, 14.95, 46.08, 13.60 %, respectively, as compared to the control. The numbers of seeds per umbel and phosphorus concentration in seed were highest in G. intraradices with 28.4 and 54.4%, respectively as compared to control and umbels per plant was also maximum (9.7 by using G. etanicatum. Mycorrhizal inoculation did not have significant effect on calcium and magnesium concentrations in seeds and 1000 seed weight. However mycorrhiza × salinity stress interaction was significant about concentration of sodium, potassium and sodium to potassium ratio (Na/K in seeds, as well as seed yield and seed number per plant. Among the species of mycorrhiza, applied G. intraradices had better performance in severe salinity (10 dS-1 and increased seed yield and seed number per plant by 28.5 and 47.6%, respectively in comparision control. The results suggested that mycorrhizal inoculation improves water absorption by plant. Yield increases of plants under different salinity regimes dependent on their mycorrhizal inoculation.

  8. Combining ability studies on yield related traits in wheat under normal and water stress conditions

    International Nuclear Information System (INIS)

    Saeed, A.; Khan, A.S.; Khaliq, I.

    2010-01-01

    Six diverse wheat cultivars/lines viz; Baviacore, Nesser, 9247, 9252, 9258 and 9267 were crossed in a complete diallel fashion to develop 30 F1 crosses, which were tested along with their parents under normal and water stress conditions. Numerical analysis was made for spike density, number of grains per spike, 100-grain weight, biological yield, grain yield and harvest index. Significant differences among genotypic mean were observed in all of the traits under both conditions. GCA and SCA differences were significant for all the traits under study except spike density and 100-grain weight in both conditions. Wheat variety Nesser showed maximum general combining ability value for spike density under water stress conditions and maximum GCA value for biological yield and grain yield under irrigated condition. The variety Baviacore proved best general combiner for number of grains per spike and harvest index under both conditions while biological yield and grain yield under water stress condition. Variety 9252 found best general combiner for 100-grain weight under both condition. The cross 9252 x Nesser showed maximum specific combining ability value for spike density and biological yield under irrigated while for 100-grain weight under water stress condition. 9258 x 9252 exhibited maximum SCA for number of grains per spike under irrigated while 9258 x Nesser under water stress condition. 9267 x Nesser showed maximum SCA for 100-grain weight under irrigated condition while spike density under water stress condition. 9258 x 9247 was proved best combiner for grain yield and harvest index irrigated while 9267 x 9258 for biological yield, grain yield and harvest index under water stress condition. (author)

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

    International Nuclear Information System (INIS)

    Al Mamun, Abdullah; Moat, Richard; Bouchard, John; Kelleher, Joe

    2016-01-01

    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)

  10. Influence of polymer charge on the shear yield stress of silica aggregated with adsorbed cationic polymers.

    Science.gov (United States)

    Zhou, Ying; Yu, Hai; Wanless, Erica J; Jameson, Graeme J; Franks, George V

    2009-08-15

    Flocs were produced by adding three cationic polymers (10% charge density, 3.0x10(5) g/mol molecular weight; 40% charge density, 1.1x10(5) g/mol molecular weight; and 100% charge density, 1.2x10(5) g/mol molecular weight) to 90 nm diameter silica particles. The shear yield stresses of the consolidated sediment beds from settled and centrifuged flocs were determined via the vane technique. The polymer charge density plays an important role in influencing the shear yield stresses of sediment beds. The shear yield stresses of sediment beds from flocs induced by the 10% charged polymer were observed to increase with an increase in polymer dose, initial solid concentration and background electrolyte concentration at all volume fractions. In comparison, polymer dose has a marginal effect on the shear yield stresses of sediment beds from flocs induced by the 40% and 100% charged polymers. The shear yield stresses of sediments from flocs induced by the 40% charged polymer are independent of salt concentration whereas the addition of salt decreases the shear yield stresses of sediments from flocs induced by the 100% charged polymer. When flocculated at the optimum dose for each polymer (12 mg/g silica for the 10% charged polymer at 0.03 M NaCl, 12 mg/g for 40% and 2 mg/g for 100%), shear yield stress increases as polymer charge increases. The effects observed are related to the flocculation mechanism (bridging, patch attraction or charge neutralisation) and the magnitude of the adhesive force. Comparison of shear and compressive yield stresses show that the network is only slightly weaker in shear than in compression. This is different than many other systems (mainly salt and pH coagulation) which have shear yield stress much less than compressive yield stress. The existing models relating the power law exponent of the volume fraction dependence of the shear yield stress to the network fractal structure are not satisfactory to predict all the experimental behaviour.

  11. Post-heading heat stress and yield impact in winter wheat of China.

    Science.gov (United States)

    Liu, Bing; Liu, Leilei; Tian, Liying; Cao, Weixing; Zhu, Yan; Asseng, Senthold

    2014-02-01

    Wheat is sensitive to high temperatures, but the spatial and temporal variability of high temperature and its impact on yield are often not known. An analysis of historical climate and yield data was undertaken to characterize the spatial and temporal variability of heat stress between heading and maturity and its impact on wheat grain yield in China. Several heat stress indices were developed to quantify heat intensity, frequency, and duration between heading and maturity based on measured maximum temperature records of the last 50 years from 166 stations in the main wheat-growing region of China. Surprisingly, heat stress between heading and maturity was more severe in the generally cooler northern wheat-growing regions than the generally warmer southern regions of China, because of the delayed time of heading with low temperatures during the earlier growing season and the exposure of the post-heading phase into the warmer part of the year. Heat stress between heading and maturity has increased in the last decades in most of the main winter wheat production areas of China, but the rate was higher in the south than in the north. The correlation between measured grain yields and post-heading heat stress and average temperature were statistically significant in the entire wheat-producing region, and explained about 29% of the observed spatial and temporal yield variability. A heat stress index considering the duration and intensity of heat between heading and maturity was required to describe the correlation of heat stress and yield variability. Because heat stress is a major cause of yield loss and the number of heat events is projected to increase in the future, quantifying the future impact of heat stress on wheat production and developing appropriate adaptation and mitigation strategies are critical for developing food security policies in China and elsewhere. © 2013 John Wiley & Sons Ltd.

  12. The Start Of Ebullition In Quiescent, Yield-Stress Fluids

    International Nuclear Information System (INIS)

    Reed, G. R.; Sherwood, David J.; Saez, A. Eduardo

    2012-01-01

    Non-Newtonian rheology is typical for the high-level radioactive waste (HLW) slurries processed in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hydrogen and other flammable gases are generated in the aqueous phase by radiolytic and chemical reactions. HLW slurries have a capacity for retaining gas characterized by the shear strength holding the bubbles still. The sizes and degassing characteristics of flammable gas bubbles in the HLW slurries expected to be processed by the WTP are important considerations for designing equipment and operating procedures. Slurries become increasingly susceptible to degassing as the bubble concentration increases. This susceptibility and the process of ebullitive bubble enlargement are described here. When disturbed, the fluid undergoes localized flow around neighboring bubbles which are dragged together and coalesce, producing an enlarged bubble. For the conditions considered in this work, bubble size increase is enough to displace the weight required to overcome the fluid shear strength and yield the surroundings. The buoyant bubble ascends and accumulates others within a zone of influence, enlarging by a few orders of magnitude. This process describes how the first bubbles appear on the surface of a 7 Pa shear strength fluid a few seconds after being jarred

  13. The Start Of Ebullition In Quiescent, Yield-Stress Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Reed, G. R.; Sherwood, David J.; Saez, A. Eduardo

    2012-08-30

    Non-Newtonian rheology is typical for the high-level radioactive waste (HLW) slurries processed in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hydrogen and other flammable gases are generated in the aqueous phase by radiolytic and chemical reactions. HLW slurries have a capacity for retaining gas characterized by the shear strength holding the bubbles still. The sizes and degassing characteristics of flammable gas bubbles in the HLW slurries expected to be processed by the WTP are important considerations for designing equipment and operating procedures. Slurries become increasingly susceptible to degassing as the bubble concentration increases. This susceptibility and the process of ebullitive bubble enlargement are described here. When disturbed, the fluid undergoes localized flow around neighboring bubbles which are dragged together and coalesce, producing an enlarged bubble. For the conditions considered in this work, bubble size increase is enough to displace the weight required to overcome the fluid shear strength and yield the surroundings. The buoyant bubble ascends and accumulates others within a zone of influence, enlarging by a few orders of magnitude. This process describes how the first bubbles appear on the surface of a 7 Pa shear strength fluid a few seconds after being jarred.

  14. Effect of Drought Stress onYield and Yield Components of Sesame cultivars under Kerman conditions (Sesamum indicum L.

    Directory of Open Access Journals (Sweden)

    S Farahbakhsh

    2015-04-01

    Full Text Available To investigate effects of drought stress on yield and yield components of sesame in Kerman region a split-plot experiment based onn compelet randomised block design with three replications was carried out in 1388. Irrigation levels (Normal irrigation in all growth stages, witholding water after 50% flowering, witholding water after 50% pod setting and differen t sesame landraces (Jiroft, Shiraz, Ardestan, Dezful, Shahr babak, Gorgan, Sirjan, Markazi, Birjand and Orzueieh were considered as main plots and sub-plots respectively. Plant height, the biggest pod length, noumber of grain per pod, noumber of pod per plant, grain weight per plant, thousand grain weight and grain yield were the measured traits. Results showed all the measured traits were significantly affected by the irrigation treatments. The effects of different landraces on all traits except noumber of grain per plant were significant. Irrigation × landraces interaction affected all measured traits except the biggest pod length significantly. The highest grain yield was recorde for Markezi landrace (845.2 kg –ha under normal irrigation and the lowest one was obtained from Jiroft landrace (104.8 kg –ha with witholding irrigation after 50% flowering.

  15. Bubble Formation in Yield Stress Fluids Using Flow-Focusing and T-Junction Devices.

    Science.gov (United States)

    Laborie, Benoit; Rouyer, Florence; Angelescu, Dan E; Lorenceau, Elise

    2015-05-22

    We study the production of bubbles inside yield stress fluids (YSFs) in axisymmetric T-junction and flow-focusing devices. Taking advantage of yield stress over capillary stress, we exhibit a robust break-up mechanism reminiscent of the geometrical operating regime in 2D flow-focusing devices for Newtonian fluids. We report that when the gas is pressure driven, the dynamics is unsteady due to hydrodynamic feedback and YSF deposition on the walls of the channels. However, the present study also identifies pathways for potential steady-state production of bubbly YSFs at large scale.

  16. Mean-Field Scenario for the Athermal Creep Dynamics of Yield-Stress Fluids

    Science.gov (United States)

    Liu, Chen; Martens, Kirsten; Barrat, Jean-Louis

    2018-01-01

    We develop a theoretical description based on an existent mean-field model for the transient dynamics prior to the steady flow of yielding materials. The mean-field model not only reproduces the experimentally observed nonlinear time dependence of the shear-rate response to an external stress, but also allows for the determination of the different physical processes involved in the onset of the reacceleration phase after the initial slowing down and a distinct fluidization phase. The fluidization time displays a power-law dependence on the distance of the applied stress to an age-dependent yield stress, which is not universal but strongly dependent on initial conditions.

  17. Effect of drought stress on growth, yield and seed quality of tomato (lycopersicon esculentum L.)

    International Nuclear Information System (INIS)

    Pervez, M.A.; Ayub, C.M.

    2009-01-01

    Plant growth is seriously affected by abiotic stresses such as drought, salinity or temperature. Drought is one of the most important limiting factors for agricultural crops and vegetable production in particular all around the world. Drought stress during vegetative or early reproductive growth usually reduces yield by reducing the number of seeds, seed size and seed quality. To assess the effect of drought stress on seed yield, seed quality and growth of tomato, the experiment was conducted in green house in plastic pots at Pen-y-Fridd field station, University of Wales, Bangor, U.K. during 2003-2004. Tomato cv. Moneymaker was used as a test crop. There were four treatments i.e. early stress (when first truss has set the fruits), middle stress (when fruits in first truss were fully matured and started changing their colour), late stress (when fruits on first truss were ripened fully), whereas in control no stress was imposed. Analysis of data regarding various attributes (fruit weight and shoot dry weight per plant, number of seeds per fruit, total number of seeds and seed weight per plant and vigour of seed) showed that drought stress had non-significant effect on vigour, quality and yield of tomato seed. Plant height, number of leaves and number of fruits per plant showed significant results toward drought stress signifying drought effects on growth of tomato. (author)

  18. Yield shear stress model of magnetorheological fluids based on exponential distribution

    International Nuclear Information System (INIS)

    Guo, Chu-wen; Chen, Fei; Meng, Qing-rui; Dong, Zi-xin

    2014-01-01

    The magnetic chain model that considers the interaction between particles and the external magnetic field in a magnetorheological fluid has been widely accepted. Based on the chain model, a yield shear stress model of magnetorheological fluids was proposed by introducing the exponential distribution to describe the distribution of angles between the direction of magnetic field and the chain formed by magnetic particles. The main influencing factors were considered in the model, such as magnetic flux density, intensity of magnetic field, particle size, volume fraction of particles, the angle of magnetic chain, and so on. The effect of magnetic flux density on the yield shear stress was discussed. The yield stress of aqueous Fe 3 O 4 magnetreological fluids with volume fraction of 7.6% and 16.2% were measured by a device designed by ourselves. The results indicate that the proposed model can be used for calculation of yield shear stress with acceptable errors. - Highlights: • A yield shear stress model of magnetorheological fluids was proposed. • Use exponential distribution to describe the distribution of magnetic chain angles. • Experimental and predicted results were in good agreement for 2 types of MR

  19. Giant intracranial aneurysm embolization with a yield stress fluid material: insights from CFD analysis.

    Science.gov (United States)

    Wang, Weixiong; Graziano, Francesca; Russo, Vittorio; Ulm, Arthur J; De Kee, Daniel; Khismatullin, Damir B

    2013-01-01

    The endovascular treatment of intracranial aneurysms remains a challenge, especially when the aneurysm is large in size and has irregular, non-spherical geometry. In this paper, we use computational fluid dynamics to simulate blood flow in a vertebro-basilar junction giant aneurysm for the following three cases: (1) an empty aneurysm, (2) an aneurysm filled with platinum coils, and (3) an aneurysm filled with a yield stress fluid material. In the computational model, blood and the coil-filled region are treated as a non-Newtonian fluid and an isotropic porous medium, respectively. The results show that yield stress fluids can be used for aneurysm embolization provided the yield stress value is 20 Pa or higher. Specifically, flow recirculation in the aneurysm and the size of the inflow jet impingement zone on the aneurysm wall are substantially reduced by yield stress fluid treatment. Overall, this study opens up the possibility of using yield stress fluids for effective embolization of large-volume intracranial aneurysms.

  20. Mobility of Yield-Stress Fluids on Lubricant-Impregnated Surface

    Science.gov (United States)

    Rapoport, Leonid; Solomon, Brian; Varanasi, Kripa; Varanasi Research Group Team

    2017-11-01

    Assuring the flow of yield-stress fluids is an essential problem for various industries such as consumer products, health care, and energy. Elimination of wall-induced pinning forces can potentially save power and cleaning costs as well as enable the flow of yield-stress fluids in channels previously considered too narrow. Lubricant-Impregnated Surfaces (LIS) have been demonstrated to change the dynamic behavior of yield-stress fluids and enable them to move as bulk without shearing at all. However, despite the wide applicability of this technology and its general appeal, the fundamental principles governing the performance of yield stress fluids on LIS have not yet been fully explained. In this work, we explore the mobility of yield stress fluids on a wide range of LIS, and explain the connection between macroscale behavior and the microscale properties of the LIS. Specifically, we show a striking difference in mobility between an LIS that contains a lubricant which fully spreads on the rough micro-features of the surface, and an LIS that contains a lubricant which only imbibes these features but does spread over them

  1. Yield stress of duplex stainless steel specimens estimated using a compound Hall–Petch equation

    Directory of Open Access Journals (Sweden)

    Noriaki Hirota, Fuxing Yin, Tsukasa Azuma and Tadanobu Inoue

    2010-01-01

    Full Text Available In this study, the 0.2% yield stress of duplex stainless steel was evaluated using a compound Hall–Petch equation. The compound Hall–Petch equation was derived from four types of duplex stainless steel, which contained 0.2–64.4 wt% δ-ferrite phase, had different chemical compositions and were annealed at different temperatures. Intragranular yield stress was measured with an ultra-microhardness tester and evaluated with the yield stress model proposed by Dao et al. Grain size, volume fraction and texture were monitored by electron backscattering diffraction measurement. The kγ constant in the compound equation for duplex stainless steel agrees well with that for γ-phase SUS316L steel in the temperature range of 1323–1473 K. The derived compound Hall–Petch equation predicts that the yield stress will be in good agreement with the experimental results for the Cr, Mn, Si, Ni and N solid-solution states. We find that the intragranular yield stress of the δ-phase of duplex stainless steel is rather sensitive to the chemical composition and annealing conditions, which is attributed to the size misfit parameter.

  2. Effect of Zeolite, Selenium and Silicon on Yield, Yield Components and Some Physiological Traits of Canola under Salt Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Bybordi

    2016-07-01

    Full Text Available Introduction Canola can be cultivated in large areas of the country due to its specific characteristics such as suitable composition of the fatty acids, its germination ability under low temperature, as well as its good compatibility with different climates. Canola is a high demanding crop in terms of fertilizers so that it uptakes considerable amount of nutrients from the soil during the growing season. Canola cultivation in poor soils or application of imbalanced fertilizers, especially nitrogen, can reduce qualitaty and quantity of final yield. On the other hand, salinity is known as one of the major limiting factors in canola production. Therefore, the aim of this study is the application of zeolite, selenium and silicon treatments to amend soil and increasing salinity tolerance in canola. Materials and Methods In order to study the effect of soil applied zeolite and foliar application of selenium and silicon on yield, yield components and some physiological traits of canola grown under salinity stress, a factorial experiment in randomized complete block design was conducted in Agriculture and Natural Resource Research Center in East Azerbaijan during 2011-2013 cropping seasons. Zeolite was applied at three levels (0, 5 and 10 ton ha-1 and foliar selenium and silicon were applied at three levels as well (each one zero, 2 and 4 g l-1. For this purpose, seedbed was prepared using plow and disk and then plot were designed. Canola seeds, cultivar Okapi, were sown in sandy loam soil with 4 dS.m-1 salinity at the depth of 2-3 cm. Irrigation was performed using local well based on 60% field capacity using the closed irrigation system. Potassium selentae and potassium silicate were used for selenium and silicon treatments. Treatments at rosette and stem elongation stages were sprayed on plants using a calibrated pressurized backpack sprayer. At flowering stage, photosynthesis rate was recorded. Then leaf samples were randomly collected to assay

  3. ATLAS: Exceeding all expectations

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    “One year ago it would have been impossible for us to guess that the machine and the experiments could achieve so much so quickly”, says Fabiola Gianotti, ATLAS spokesperson. The whole chain – from collision to data analysis – has worked remarkably well in ATLAS.   The first LHC proton run undoubtedly exceeded expectations for the ATLAS experiment. “ATLAS has worked very well since the beginning. Its overall data-taking efficiency is greater than 90%”, says Fabiola Gianotti. “The quality and maturity of the reconstruction and simulation software turned out to be better than we expected for this initial stage of the experiment. The Grid is a great success, and right from the beginning it has allowed members of the collaboration all over the world to participate in the data analysis in an effective and timely manner, and to deliver physics results very quickly”. In just a few months of data taking, ATLAS has observed t...

  4. Residual Effect of Chemical and Animal Fertilizers and Compost on Yield, YieldComponents, Physiological Characteristics and Essential Oil Content of Matricaria chamomilla L. under Drought Stress conditions

    Directory of Open Access Journals (Sweden)

    a Ahmadian

    2011-02-01

    Full Text Available Abstract The residual effect of inorganic and organic fertilizers on growth and yield of plants is one of the important problems in nutrition. This study was conducted to determine the residual effect of different fertilizers on yield, yield components, physiological parameters and essential oil percentage of Matricaria chamomilla under drought stress. A split plot arrangement based on randomized completely block design (RCBD with three replication was conducted in 2009, at the University of Zabol. Treatments included W1 (non stress, W2 (75% FC and W3 (50% FC as main plot and three types of residual’s fertilizers: F1 (non fertilizer, F2 (chemical fertilizer, F3 (manure fertilizer and F4 (compost as sub plot. Results showed that water stress at W3 treatment reduced dry flower yield. Low water stress increased essential oil percentage and the highest oil was obtained in W2. In this experiment, free proline and total soluble carbohydrate concentration were increased under water stress. The residual’s manure and compost enhanced flower yield, percentage and yield of essential oil of chamomile at the second year. At a glance, animal manure application and light water stress (75% FC was recommended to obtain best quantitative and qualitative yield. Keywords: Water Stress, Fertilizer, Carbohydrate, Proline, Chamomile

  5. Crop yield response to water stress imposed at different growth stages

    International Nuclear Information System (INIS)

    Iqbal, M.; Mahmood Shah, M.; Wisal, M.

    1995-01-01

    Potato requires sufficient soil moisture and fertilization to produce high yields but the present water resoures are limited compared to the cultivable land, field experiments were conduced from 1991 to 1995 to study relationship between yield and crop water use as a function of water stress imposed at different growth stages. The irrigation treatments involved application of full and stress watering s selectively at four growth stages : Establishment , Flowering Tuber formation and ripening. In full watering, full water requirements of the crop were met, i.e., ET sub a = ET sub m whereas in stress watering about half the amount of full watering was applied, i.e., ET sub a < ET sub m. Changes in moisture content of the soil pre files after irrigation were monitored with the help of neutron moisture probe in order to compute ET sub a by the water balance method. The results obtained showed that the tuber yield was produced by full watering ( T 1) and the lowest by continuous stress watering (T 2). A plot of relative yield against relative evapotranspiration deficit revealed that ripening was the lest sensitive whereas early development followed by flowering the most sensitive growth stage to water stress. The crop water use efficiencies were generally higher in the treatments where a combination of normal and stress watering was applied compared to where all - normal watering s were applied. The traditional irrigation practice resulted in wasteful water application with relatively lower yields, hence the results from this project will have high value for the farming community to get this higher yields with scarce water resources. The studies with labelled fertilizer showed that planting and earthing - up were equally important growth stages of potato for applying fertilizer for its efficient utilization. 3 figs; 25 tabs; 12 refs (Author)

  6. Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianfeng, E-mail: zhoujianfeng@njtech.edu.cn [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Mo, Jingwen [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Shao, Chunlei [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Li, Zhigang [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2015-09-01

    In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress.

  7. Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

    International Nuclear Information System (INIS)

    Zhou, Jianfeng; Mo, Jingwen; Shao, Chunlei; Li, Zhigang

    2015-01-01

    In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress

  8. Experimental determination of the yield stress curve of the scotch pine wood materials

    Science.gov (United States)

    Günay, Ezgi; Aygün, Cevdet; Kaya, Şükrü Tayfun

    2013-12-01

    Yield stress curve is determined for the pine wood specimens by conducting a series of tests. In this work, pinewood is modeled as a composite material with transversely isotropic fibers. Annual rings (wood grain) of the wood specimens are taken as the major fiber directions with which the strain gauge directions are aligned. For this purpose, three types of tests are arranged. These are tensile, compression and torsion loading tests. All of the tests are categorized with respect to fiber orientations and their corresponding loading conditions. Each test within these categories is conducted separately. Tensile and compression tests are conducted in accordance with standards of Turkish Standards Institution (TSE) whereas torsion tests are conducted in accordance with Standards Australia. Specimens are machined from woods of Scotch pine which is widely used in boat building industries and in other structural engineering applications. It is determined that this species behaves more flexibly than the others. Strain gauges are installed on the specimen surfaces in such a way that loading measurements are performed along directions either parallel or perpendicular to the fiber directions. During the test and analysis phase of yield stress curve, orientation of strain gauge directions with respect to fiber directions are taken into account. The diagrams of the normal stress vs. normal strain or the shear stress vs. shear strain are plotted for each test. In each plot, the yield stress is determined by selecting the point on the diagram, the tangent of which is having a slope of 5% less than the slope of the elastic portion of the diagram. The geometric locus of these selected points constitutes a single yield stress curve on σ1-σ2 principal plane. The resulting yield stress curve is plotted as an approximate ellipse which resembles Tsai-Hill failure criterion. The results attained in this work, compare well with the results which are readily available in the literature.

  9. Effect of the plate surface characteristics and gap height on yield stresses of a magnetorheological fluid

    International Nuclear Information System (INIS)

    Jonkkari, I; Syrjala, S; Kostamo, E; Kostamo, J; Pietola, M

    2012-01-01

    Effects of the plate material, surface roughness and measuring gap height on static and dynamic yield stresses of a magnetorheological (MR) fluid were investigated with a commercial plate–plate magnetorheometer. Magnetic and non-magnetic plates with smooth (Ra ∼ 0.3 μm) and rough (Ra ∼ 10 μm) surface finishes were used. It was shown by Hall probe measurements and finite element simulations that the use of magnetic plates or higher gap heights increases the level of magnetic flux density and changes the shape of the radial flux density profile. The yield stress increase caused by these factors was determined and subtracted from the measured values in order to examine only the effect of the wall characteristics or the gap height. Roughening of the surfaces offered a significant increase in the yield stresses for non-magnetic plates. With magnetic plates the yield stresses were higher to start with, but roughening did not increase them further. A significant part of the difference in measured stresses between rough non-magnetic and magnetic plates was caused by changes in magnetic flux density rather than by better contact of the particles to the plate surfaces. In a similar manner, an increase in gap height from 0.25 to 1.00 mm can lead to over 20% increase in measured stresses due to changes in the flux density profile. When these changes were compensated the dynamic yield stresses generally remained independent of the gap height, even in the cases where it was obvious that the wall slip was present. This suggests that with MR fluids the wall slip cannot be reliably detected by comparison of flow curves measured at different gap heights. (paper)

  10. Effect of Different Level of Water Stress and Nitrogen Fertilizer on Yield and Yield Components of Barley in Badjgah (Fars province

    Directory of Open Access Journals (Sweden)

    ali asghar ghaemi

    2016-02-01

    fertilizer consumption will be decreased gradually in most cases, 225 kg/ha nitrogen fertilizer treatment caused most of crop yield parametersbut the differences of crop yield at this treatment with 150kg/ha nitrogen fertilizer treatment wasnot significant. Water use efficiency for 50% deficit irrigation treatment was 0.77 and for 100% irrigation treatment was 0.55. Regarding the results obtained from this study andexisting water crisis problem in Iran, it can be noted that the irrigation ofbarley should not be exceeded more than the 100% of crop water consumption use but using 75% of water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the area. Conclusion: This study was conducted in order to determinethe yield performance of barley (BahmanspeciesinBadjgah (Fars Provienceusing three different irrigation treatments of 100, 75 and 50 percent of crop water requirement (based on the total available water plant and three nitrogen treatments include 225, 150 and 75 kg/ ha in the spring and autumn cultivation. In terms of deficit irrigation, during the growing season crop will interface with different intensities and durations of water stress. This tension changes in response to nitrogen fertilizer by plant that creates unpredictable and in some cases is not always the same.Statistical analysis showed that there are significant differencesbetweenthe different treatments of irrigation, nitrogen fertilizer and their interaction.Applying 75% of barley water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the study area.

  11. Nanoscale Roughness of Faults Explained by the Scale-Dependent Yield Stress of Geologic Materials

    Science.gov (United States)

    Thom, C.; Brodsky, E. E.; Carpick, R. W.; Goldsby, D. L.; Pharr, G.; Oliver, W.

    2017-12-01

    Despite significant differences in their lithologies and slip histories, natural fault surfaces exhibit remarkably similar scale-dependent roughness over lateral length scales spanning 7 orders of magnitude, from microns to tens of meters. Recent work has suggested that a scale-dependent yield stress may result in such a characteristic roughness, but experimental evidence in favor of this hypothesis has been lacking. We employ an atomic force microscope (AFM) operating in intermittent-contact mode to map the topography of the Corona Heights fault surface. Our experiments demonstrate that the Corona Heights fault exhibits isotropic self-affine roughness with a Hurst exponent of 0.75 +/- 0.05 at all wavelengths from 60 nm to 10 μm. If yield stress controls roughness, then the roughness data predict that yield strength varies with length scale as λ-0.25 +/ 0.05. To test the relationship between roughness and yield stress, we conducted nanoindentation tests on the same Corona Heights sample and a sample of the Yair Fault, a carbonate fault surface that has been previously characterized by AFM. A diamond Berkovich indenter tip was used to indent the samples at a nominally constant strain rate (defined as the loading rate divided by the load) of 0.2 s-1. The continuous stiffness method (CSM) was used to measure the indentation hardness (which is proportional to yield stress) and the elastic modulus of the sample as a function of depth in each test. For both samples, the yield stress decreases with increasing size of the indents, a behavior consistent with that observed for many engineering materials and recently for other geologic materials such as olivine. The magnitude of this "indentation size effect" is best described by a power-law with exponents of -0.12 +/- 0.06 and -0.18 +/- 0.08 for the Corona Heights and Yair Faults, respectively. These results demonstrate a link between surface roughness and yield stress, and suggest that fault geometry is the physical

  12. Effect of the Yield Stress and r-value Distribution on the Earing Profile of Cup Drawing with Yld2000-2d Yield Function

    Science.gov (United States)

    Lou, Yanshan; Bae, Gihyun; Lee, Changsoo; Huh, Hoon

    2010-06-01

    This paper deals with the effect of the yield stress and r-value distribution on the earing in the cup drawing. The anisotropic yield function, Yld2000-2d yield function, is selected to describe the anisotropy of two metal sheets, 719B and AA5182-O. The tool dimension is referred from the Benchmark problem of NUMISHEET'2002. The Downhill Simplex method is applied to identify the anisotropic coefficients in Yld2000-2d yield function. Simulations of the drawing process are performed to investigate the earing profile of two materials. The earing profiles obtained from simulations are compared with the analytical model developed by Hosford and Caddell. Simulations are conducted with respect to the change of the yield stress and r-value distribution, respectively. The correlation between the anisotropy and the earing tendency is investigated based on simulation data. Finally, the earing mechanism is analyzed through the deformation process of the blank during the cup deep drawing. It can be concluded that ears locate at angular positions with lower yield stress and higher r-value while the valleys appear at the angular position with higher yield stress and lower r-value. The effect of the yield stress distribution is more important for the cup height distribution than that of the r-value distribution.

  13. The Effect of Drought Stress on Morphological Characteristics and Yield Components of Medicinal Plant Fenugreek

    Directory of Open Access Journals (Sweden)

    N. Bazzazi

    2013-06-01

    Full Text Available Fenugreek (Trigonella foenum-graecum L. is one of the oldest medicinal plants. In order to study water-stress effects on some morphological characteristics of fenugreek, an experiment was carried out in a strip plots based on randomized complete blocks design with three replicates, at Research Farm of Shahrekord University, Shahrekord, Iran, in 2010. The first factor was allocated to four water stress levels (irrigation after depletion of 20 (as control, 40, 60 and 80% of available soil moisture and the second factor was six fenugreek landraces (Shiraz, Ardestan, Tirancheh, Yazd, Jahrom and Hindi. The results of ANOVA and comparison of means indicated that the effect of water stress was significant for all traits and variation was observed among landraces for all the studied characteristics. Mean comparison showed that drought stress reduced days to flowering, days to maturity, plant height and yield components (number of pods per plant, number of seeds per pod and 1000-kernel weight. It was also revealed that water stress caused reduction in biological yield (43% and grain yield (42.3% of all genotypes. Comparison between landraces indicated that maximum biological and grain yield belonged to Ardestan landrace. Assessment of cluster analysis showed that it was possible to classify Ardestan, Shiraz and Tirancheh as a single group having tolerance to water stress. In general, based on obtained results, the Ardestan landrace, with 22.37 g/plant, had the highest biological yield and Hindi landrace, with 73.83 days to maturity, was the most early-maturing one.

  14. Global crop yield response to extreme heat stress under multiple climate change futures

    Science.gov (United States)

    Deryng, D.; Conway, D.; Ramankutty, N.; Price, J.; Warren, R.

    2014-12-01

    Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO2 fertilization effects, could double global losses of maize yield (dY = -12.8 ± 6.7% versus -7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (dY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (dY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

  15. A water stress index based on water balance modelling for discrimination of grapevine quality and yield

    Directory of Open Access Journals (Sweden)

    Rémi Gaudin

    2014-01-01

    Significance and impact of the study: This water stress index is a valuable tool for explaining the variations in grape yield and quality among various locations and years because it reflects the vineyard water stress history in relation to rainfall regime and soil conditions. Improvement would come from the simulation of FTSW during winter, notably for soils of high Total Transpirable Soil Water. One potential application is the quantification of water stress change brought by irrigation in Mediterranean vineyards, and its relation to grapevine production.

  16. Crop coefficient, yield response to water stress and water productivity of teff (Eragrostis tef (Zucc.)

    NARCIS (Netherlands)

    Araya, A.; Stroosnijder, L.; Girmay, G.; Keesstra, S.D.

    2011-01-01

    In the semi-arid region of Tigray, Northen Ethiopia a two season experiment was conducted to measure evapotranspiration, estimate yield response to water stress and derive the crop coefficient of teff using the single crop coefficient approach with simple, locally made lysimeters and field plots.

  17. Suction pressure, yield strength and effective stress of partially saturated unbound granular pavement layers

    CSIR Research Space (South Africa)

    Theyse, HL

    2006-09-01

    Full Text Available to the ratio of the imposed stress over the shear strength of the material. Conventionally, the shear strength of the material was characterised with the Mohr-Coulomb shear strength parameters. This paper further develops a recent yield strength model...

  18. Effects of shade and drought stress on soybean hormones and yield ...

    African Journals Online (AJOL)

    Multiple frequently interactive stress factors naturally influence plant due to global change. The leaf's hormone concentrations, main-stem and branch yield response to the combination of shade and drought were studied in a greenhouse experiment during 2009 and 2010 seasons. Pot experiments were conducted under ...

  19. Effects of drought stress and different densities on oil yield and ...

    African Journals Online (AJOL)

    For evaluation of water deficit stress and planting density effects on the oil and biological yield attributes of sunflower, an experiment was conducted in a randomized complete block design (RCBD) based split plot factorial design in three replications in the research field of Baku State University, Baku, Azerbaijan, in 2009.

  20. Optimization of MR fluid Yield stress using Taguchi Method and Response Surface Methodology Techniques

    Science.gov (United States)

    Mangal, S. K.; Sharma, Vivek

    2018-02-01

    Magneto rheological fluids belong to a class of smart materials whose rheological characteristics such as yield stress, viscosity etc. changes in the presence of applied magnetic field. In this paper, optimization of MR fluid constituents is obtained with on-state yield stress as response parameter. For this, 18 samples of MR fluids are prepared using L-18 Orthogonal Array. These samples are experimentally tested on a developed & fabricated electromagnet setup. It has been found that the yield stress of MR fluid mainly depends on the volume fraction of the iron particles and type of carrier fluid used in it. The optimal combination of the input parameters for the fluid are found to be as Mineral oil with a volume percentage of 67%, iron powder of 300 mesh size with a volume percentage of 32%, oleic acid with a volume percentage of 0.5% and tetra-methyl-ammonium-hydroxide with a volume percentage of 0.7%. This optimal combination of input parameters has given the on-state yield stress as 48.197 kPa numerically. An experimental confirmation test on the optimized MR fluid sample has been then carried out and the response parameter thus obtained has found matching quite well (less than 1% error) with the numerically obtained values.

  1. Analysis of the yielding behavior of electrorheological suspensions by controlled shear stress experiments

    Czech Academy of Sciences Publication Activity Database

    Pavlínek, V.; Sáha, P.; Perez-Gonzales, K.; de Vargas, L.; Stejskal, Jaroslav; Quadrat, Otakar

    2006-01-01

    Roč. 16, 1-2 (2006), s. 14-18 ISSN 1430-6395 R&D Projects: GA ČR GA202/06/0419 Institutional research plan: CEZ:AV0Z40500505 Keywords : electrorheology * yield stress * suspensions * polyaniline Subject RIV: CD - Macromolecular Chemistry

  2. Effect of soil water stress on yield and proline content of four wheat ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-04

    Jan 4, 2010 ... Four lines of bread wheat (N-82-9, N-83-5, ... Key words: Water stress, Triticum aestivum, yield, proline, TSS. .... Numbers in the columns followed by the same letters are not significantly different at P .... constituents, Acta Bot.

  3. Evaluation of drought tolerance and yield capacity of barley (hordeum vulgare) genotypes under irrigated and water-stressed conditions

    International Nuclear Information System (INIS)

    Khokhar, M.I.; Silva, J.A.T.D

    2012-01-01

    Twelve barley genotypes developed through different selection methods were evaluated under drought and irrigated conditions. The results of a correlation matrix revealed highly significant associations between Grain Yield (Yp) and Mean Productivity (MP), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Yield Index (Yi) under irrigated conditions while the Mean Productivity (MP), Yield Stability Index (Yi), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Yield Index (Yi) had a high response under stressed condition. Based on a principal component analysis, Geometric Mean Productivity (GMP), Mean Productivity (MP) and Stress Tolerance Index (STI) were considered to be the best parameters for selection of drought-tolerant genotypes. The 2-row barley genotypes B-07023 and B-07021 performed better in yield response under drought conditions and were more stable under stress conditions. Furthermore, drought stress reduced the yield of some genotypes while others were tolerant to drought, suggesting genetic variability in this material for drought tolerance. (author)

  4. Effect of Black and Clear Polyethylene Mulch on Yield and Yield Components of Melon in Salinity Stress Condition

    Directory of Open Access Journals (Sweden)

    Peyman Jafari

    2017-02-01

    Full Text Available Introduction: The term of Mulch, is the German word (Molsh means the soft, however, not soft, and made of plant debris or synthetic substances. Many positive effects attributed to the use of plastic mulch such as adjusting the temperature in the root environment, conserve moisture, reduce weeds, increase root growth, reduce soil erosion, and soil condensation and improve germination and early plant establishment. The use of mulch can reduce the harmful effects of salt in plants. Materials and Methods: To evaluate the effects of black and clear polyethylene mulch on yield and yield components of melon in salinity stress condition, a study was conducted in 2011 using split plot randomized based on complete block design with three replications in Varamin region. Three salinity levels of irrigation water of 2, 5 and 8 dS-1 as main factor and three plastic mulch treatments (no mulch, clear mulch and black mulch were considered as sub-plots. At harvest and after determining the yield and number of fruits harvested from each plot, the average number of fruits per plant was measured and fruit pulp thickness was recorded with calipers. Results Discussion The results showed interactive effects of salinity and mulch on fruit yield, number of fruits per plant, average fruit weight, fruit length, days to first harvest and fruit soluble solids percentage were statistically significant. In salinity levels of 2, 5 and 8 dS m-1, fruit yield increased, respectively, 19.6, 59, and 45.4 %in clear mulch compared to control. Similarly these increases for the black mulch were equal to 15.7, 41.9, and 21.4 percent, respectively. With 2, 5 and 8 dS m-1 salinity levels, fruit yield in the first harvest were 7.44, 7.72, and 6.98 t ha -1, respectively, which was significantly higher than without mulch and black mulch. Mulch can reduce evaporation and increase the level of moisture in the soil and thereby dilute the salt and reduce the harmful effects of salinity. Some

  5. Improving Wheat Growth and Yield Using Chlormequat Chloride, Salicylic Acid and Jasmonic Acid under Water Stress

    Directory of Open Access Journals (Sweden)

    N Vahabi

    2017-06-01

    Full Text Available Introduction Drought stress is most important abiotic stress reducing growth and production of wheat worldwide. Protective role of plant growth regulators (PGRs against drought stress has been accepted in general, however, comparison of PGRs types to determine the optimum one is crucial. Many PGRs are known to alleviate the negative effects of drought stress in plants. However, limited research has been conducted to investigate the potential benefits of exogenous application of different PGRs in wheat plants grown under drought stress. Chlormequat chloride (CCC, salicylic acid (SA and jasmonic acid (JA could consider as three major PGRs using in cereals. Materials and Methods To examine the effect of three PGRs consisted of CCC, SA and JA on yield components and grain yield of wheat cv. Roshan under different water stress conditions (a range of light to severe drought levels two separated experiments were conducted at controlled and field conditions at College of Agriculture, Shiraz University during 2012-2013 growing seasons. Concentration of CCC, SA and JA were 19.0, 1.0 and 0.1 mM, respectively. Drought stress levels were 100%, 80%, 60% and 40% of field capacity in greenhouse and were 100%, 2/3 and 1/5 of field capacity in the field experiment. Field capacity was determined as 25% (g g-1 for the experimental field. Greenhouse and field researches were carried out in factorial experiment based on completely randomized design and in split plot experiment based on randomized complete block design, respectively. Four and three replications were used greenhouse and field experiments, respectively. Roshan as a bread wheat cultivar with standard height was used. Foliar application of 3 PGRs was done at double ridges stage in both experiments; however, irrigation treatments were applied at double ridges stage and early anthesis at greenhouse and field experiment, respectively. For plot irrigation a tape system was used and amount of irrigation was

  6. 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.

  7. Improvement of wheat yield grown under drought stress by boron foliar application at different growth stages

    Directory of Open Access Journals (Sweden)

    F.M.F. Abdel-Motagally

    2018-04-01

    Full Text Available Two field experiments were conducted to determine the effect of boron foliar application and water stress on yield of wheat plant grown in calcareous soil during 2013/2014 and 2014/2015 seasons. The highest mean values obtained against boron application time were potential contributor to total grains mass by improving the plant height (99.42 and 98.32 cm, spike length (11.86 and 11.72 cm, number of spikelets m−2 (332.65 and 324.35, grain yield plant−1 (21.56 and 20.26 g, 1000-grain weight (35.2 and 37.4 g and grain yield (1.87 and 1.85 ton fed.−1, which were recorded at normal irrigation level (100% from the amount of water consumption for wheat with boron spraying at booting stage (B1 in the first and second seasons, respectively. Furthermore, boron application significantly enhanced all studied growth traits under water stress levels (50% from the amount of water consumption for wheat compared to B-untreated plants. Boron spraying at booting stage enhances also plant pigments contents recording its highest mean values under normal water level (100% from the amount of water consumption for wheat. The reduction in stress markers (proline and H2O2 and the enhancement of plant pigments content under water stress levels (50% from the amount of water consumption for wheat by B spraying suggests an alleviating effect of boron foliar application to water stress in the test plant. This alleviating effect was more pronounced when B applied at booting stage. Therefore, booting stage was found to be the best time for boron application to get higher grains production and consequently, better economic returns of wheat. Keywords: Wheat, Growth stages, Boron application time, Water stress, Crop yield, Plant pigments, Proline, H2O2

  8. An Efficient Return Algorithm For Non-Associated Plasticity With Linear Yield Criteria In Principal Stress Space

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars

    2007-01-01

    . The stress return and the formation of the constitutive matrix is carried out in principal stress space. Here the manipulations simplify and rely on geometrical arguments. The singularities arising at the intersection of yield planes are dealt with in a straightforward way also based on geometrical......An efficient return algorithm for stress update in numerical plasticity computations is presented. The yield criterion must be linear in principal stress space and can be composed of any number of yield planes. Each of these yield planes may have an associated or non-associated flow rule...

  9. The influence of aging stress on the yield point phenomenon in the zirconium alloy, ozhennite 0.5

    International Nuclear Information System (INIS)

    Dickson, J.I.; Sayar, A.

    1977-01-01

    The influence of aging stress on the occurrence of yield points during interrupted tensile tests was studied in the temperature range 423 to 623 K for aging times of 2 to 10 min. The results indicate that at the lower temperatures the yield points are produced by dislocation rearrangements, with a minimum yield drop resulting from an aging close to the internal stress estimated by an unloading to zero stress relaxation technique. Above approximately 458 K, solute atoms can play an important role in the formation of the yield points. When this solute strain-aging occurs strongly, a maximum yield drop is at times obtained by aging at a stress close to the measured internal stress. At the higher deformation temperatures, the yield drop decreases more rapidly with increasing plastic strain, which result appears related to the greater amount of tangling of dislocations produced at the higher temperatures. (Auth.)

  10. Modelling climate change impacts on viticultural yield, phenology and stress conditions in Europe.

    Science.gov (United States)

    Fraga, Helder; García de Cortázar Atauri, Iñaki; Malheiro, Aureliano C; Santos, João A

    2016-11-01

    Viticulture is a key socio-economic sector in Europe. Owing to the strong sensitivity of grapevines to atmospheric factors, climate change may represent an important challenge for this sector. This study analyses viticultural suitability, yield, phenology, and water and nitrogen stress indices in Europe, for present climates (1980-2005) and future (2041-2070) climate change scenarios (RCP4.5 and 8.5). The STICS crop model is coupled with climate, soil and terrain databases, also taking into account CO 2 physiological effects, and simulations are validated against observational data sets. A clear agreement between simulated and observed phenology, leaf area index, yield and water and nitrogen stress indices, including the spatial differences throughout Europe, is shown. The projected changes highlight an extension of the climatic suitability for grapevines up to 55°N, which may represent the emergence of new winemaking regions. Despite strong regional heterogeneity, mean phenological timings (budburst, flowering, veraison and harvest) are projected to undergo significant advancements (e.g. budburst/harvest can be >1 month earlier), with implications also in the corresponding phenophase intervals. Enhanced dryness throughout Europe is also projected, with severe water stress over several regions in southern regions (e.g. southern Iberia and Italy), locally reducing yield and leaf area. Increased atmospheric CO 2 partially offsets dryness effects, promoting yield and leaf area index increases in central/northern Europe. Future biomass changes may lead to modifications in nitrogen demands, with higher stress in northern/central Europe and weaker stress in southern Europe. These findings are critical decision support systems for stakeholders from the European winemaking sector. © 2016 John Wiley & Sons Ltd.

  11. Universal rescaling of flow curves for yield-stress fluids close to jamming

    Science.gov (United States)

    Dinkgreve, M.; Paredes, J.; Michels, M. A. J.; Bonn, D.

    2015-07-01

    The experimental flow curves of four different yield-stress fluids with different interparticle interactions are studied near the jamming concentration. By appropriate scaling with the distance to jamming all rheology data can be collapsed onto master curves below and above jamming that meet in the shear-thinning regime and satisfy the Herschel-Bulkley and Cross equations, respectively. In spite of differing interactions in the different systems, master curves characterized by universal scaling exponents are found for the four systems. A two-state microscopic theory of heterogeneous dynamics is presented to rationalize the observed transition from Herschel-Bulkley to Cross behavior and to connect the rheological exponents to microscopic exponents for the divergence of the length and time scales of the heterogeneous dynamics. The experimental data and the microscopic theory are compared with much of the available literature data for yield-stress systems.

  12. Global crop yield response to extreme heat stress under multiple climate change futures

    International Nuclear Information System (INIS)

    Deryng, Delphine; Warren, Rachel; Conway, Declan; Ramankutty, Navin; Price, Jeff

    2014-01-01

    Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO 2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO 2 fertilization effects, could double global losses of maize yield (ΔY = −12.8 ± 6.7% versus − 7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (ΔY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (ΔY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO 2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries. (paper)

  13. TECHNICAL NOTE: The strengthening effect of guar gum on the yield stress of magnetorheological fluid

    Science.gov (United States)

    Wu, Wei Ping; Zhao, Bin Yuan; Wu, Qing; Chen, LeSheng; Hu, Ke Ao

    2006-08-01

    In this paper we present a novel approach for producing obvious strengthening of the magnetorheological (MR) effect of MR fluids. Carbonyl iron powders coated with guar gum were used as magnetic particles in the MR fluid. Experimental results showed that inducing a guar gum coating not only greatly improved the sedimentation stability but also strengthened the yield stress of the MR fluid. An intermolecular force based model was proposed for explaining the strengthening effect.

  14. Genotype x environment interaction for grain yield of wheat genotypes tested under water stress conditions

    International Nuclear Information System (INIS)

    Sail, M.A.; Dahot, M.U.; Mangrio, S.M.; Memon, S.

    2007-01-01

    Effect of water stress on grain yield in different wheat genotypes was studied under field conditions at various locations. Grain yield is a complex polygenic trait influenced by genotype, environment and genotype x environment (GxE) interaction. To understand the stability among genotypes for grain yield, twenty-one wheat genotypes developed Through hybridization and radiation-induced mutations at Nuclear Institute of Agriculture (NIA) TandoJam were evaluated with four local check varieties (Sarsabz, Thori, Margalla-99 and Chakwal-86) in multi-environmental trails (MET/sub s/). The experiments were conducted over 5 different water stress environments in Sindh. Data on grain yield were recorded from each site and statistically analyzed. Combined analysis of variance for all the environments indicated that the genotype, environment and genotype x environment (GxE) interaction were highly significant (P greater then 0.01) for grain yield. Genotypes differed in their response to various locations. The overall highest site mean yield (4031 kg/ha) recorded at Moro and the lowest (2326 kg/ha) at Thatta. Six genotypes produced significantly (P=0.01) the highest grain yield overall the environments. Stability analysis was applied to estimate stability parameters viz., regression coefficient (b), standard error of regression coefficient and variance due to deviation from regression (S/sub 2/d) genotypes 10/8, BWS-78 produced the highest mean yield over all the environments with low regression coefficient (b=0.68, 0.67 and 0.63 respectively and higher S/sup 2/ d value, showing specific adaptation to poor (un favorable) environments. Genotype 8/7 produced overall higher grain yield (3647 kg/ha) and ranked as third high yielding genotype had regression value close to unity (b=0.9) and low S/sup d/ value, indicating more stability and wide adaptation over the all environments. The knowledge of the presence and magnitude of genotype x environment (GE) interaction is important to

  15. Ectopic expression of specific GA2 oxidase mutants promotes yield and stress tolerance in rice.

    Science.gov (United States)

    Lo, Shuen-Fang; Ho, Tuan-Hua David; Liu, Yi-Lun; Jiang, Mirng-Jier; Hsieh, Kun-Ting; Chen, Ku-Ting; Yu, Lin-Chih; Lee, Miin-Huey; Chen, Chi-Yu; Huang, Tzu-Pi; Kojima, Mikiko; Sakakibara, Hitoshi; Chen, Liang-Jwu; Yu, Su-May

    2017-07-01

    A major challenge of modern agricultural biotechnology is the optimization of plant architecture for enhanced productivity, stress tolerance and water use efficiency (WUE). To optimize plant height and tillering that directly link to grain yield in cereals and are known to be tightly regulated by gibberellins (GAs), we attenuated the endogenous levels of GAs in rice via its degradation. GA 2-oxidase (GA2ox) is a key enzyme that inactivates endogenous GAs and their precursors. We identified three conserved domains in a unique class of C 20 GA2ox, GA2ox6, which is known to regulate the architecture and function of rice plants. We mutated nine specific amino acids in these conserved domains and observed a gradient of effects on plant height. Ectopic expression of some of these GA2ox6 mutants moderately lowered GA levels and reprogrammed transcriptional networks, leading to reduced plant height, more productive tillers, expanded root system, higher WUE and photosynthesis rate, and elevated abiotic and biotic stress tolerance in transgenic rice. Combinations of these beneficial traits conferred not only drought and disease tolerance but also increased grain yield by 10-30% in field trials. Our studies hold the promise of manipulating GA levels to substantially improve plant architecture, stress tolerance and grain yield in rice and possibly in other major crops. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  16. Correlation between yield stress and hardness of nickel–silicon–boron-based alloys by nanoindentation

    International Nuclear Information System (INIS)

    Şerban, Viorel-Aurel; Codrean, Cosmin; Vodă, Mircea; Chicot, Didier; Decoopman, Xavier

    2014-01-01

    Based on the relation proposed by Tabor in 1951, which connects the ultimate tensile strength and the yield stress of classical materials to the Brinell or Vickers hardness numbers by a simple factor of proportionality, we propose an extended analytical model for the determination of the yield stress of brittle materials using nanoindentation data. This model considers the nanoindentation hardness calculated from the projected actual contact area between the indenter and the material which is representative of the real mean pressure exerted by the indenter compared to classical hardness numbers. A coefficient is introduced in the model to integrate the extent of the elastic recovery of the indented material occurring after the withdrawal of the indenter. This is possible by using the criterion defined by the residual to maximum indenter displacements ratio, this criterion being already related to the deformation mode under indentation. Indeed, this criterion allows identifying the piling-up deformation observed for complete or fully plastic deformation materials or the sinking-in deformation for purely elastic materials. The proposed model thus allows a good estimation of the yield stress of brittle materials for which classical tensile tests are not applicable. The model is validated on a variety of amorphous nickel–silicon-based alloy ribbons, i.e., Ni 89 Si 9 B 2 , Ni 78 Si 9 B 13 and Ni 68 Fe 3 Cr 7 Si 8 B 14 on which both nanoindentation tests and tensile experiments have been performed

  17. Boron application improves yield of rice cultivars under high temperature stress during vegetative and reproductive stages.

    Science.gov (United States)

    Shahid, Mohammad; Nayak, Amaresh Kumar; Tripathi, Rahul; Katara, Jawahar Lal; Bihari, Priyanka; Lal, Banwari; Gautam, Priyanka

    2018-04-12

    It is reported that high temperatures (HT) would cause a marked decrease in world rice production. In tropical regions, high temperatures are a constraint to rice production and the most damaging effect is on spikelet sterility. Boron (B) plays a very important role in the cell wall formation, sugar translocation, and reproduction of the rice crop and could play an important role in alleviating high temperature stress. A pot culture experiment was conducted to study the effect of B application on high temperature tolerance of rice cultivars in B-deficient soil. The treatments comprised of four boron application treatments viz. control (B0), soil application of 1 kg B ha -1 (B1), soil application of 2 kg B ha -1 (B2), and foliar spray of 0.2% B (Bfs); three rice cultivars viz. Annapurna (HT stress tolerant), Naveen, and Shatabdi (both HT stress susceptible); and three temperature regimes viz. ambient (AT), HT at vegetative stage (HTV), and HT at reproductive stage (HTR). The results revealed that high temperature stress during vegetative or flowering stage reduced grain yield of rice cultivars mainly because of low pollen viability and spikelet fertility. The effects of high temperature on the spikelet fertility and grain filling varied among cultivars and the growth stages of plant when exposed to the high temperature stress. Under high temperature stress, the tolerant cultivar displays higher cell membrane stability, less accumulation of osmolytes, more antioxidant enzyme activities, and higher pollen viability and spikelet fertility than the susceptible cultivars. In the present work, soil application of boron was effective in reducing the negative effects of high temperature both at vegetative and reproductive stages. Application of B results into higher grain yield under both ambient and high temperature condition over control for all the three cultivars; however, more increase was observed for the susceptible cultivar over the tolerant one. The results

  18. Boron application improves yield of rice cultivars under high temperature stress during vegetative and reproductive stages

    Science.gov (United States)

    Shahid, Mohammad; Nayak, Amaresh Kumar; Tripathi, Rahul; Katara, Jawahar Lal; Bihari, Priyanka; Lal, Banwari; Gautam, Priyanka

    2018-04-01

    It is reported that high temperatures (HT) would cause a marked decrease in world rice production. In tropical regions, high temperatures are a constraint to rice production and the most damaging effect is on spikelet sterility. Boron (B) plays a very important role in the cell wall formation, sugar translocation, and reproduction of the rice crop and could play an important role in alleviating high temperature stress. A pot culture experiment was conducted to study the effect of B application on high temperature tolerance of rice cultivars in B-deficient soil. The treatments comprised of four boron application treatments viz. control (B0), soil application of 1 kg B ha-1 (B1), soil application of 2 kg B ha-1 (B2), and foliar spray of 0.2% B (Bfs); three rice cultivars viz. Annapurna (HT stress tolerant), Naveen, and Shatabdi (both HT stress susceptible); and three temperature regimes viz. ambient (AT), HT at vegetative stage (HTV), and HT at reproductive stage (HTR). The results revealed that high temperature stress during vegetative or flowering stage reduced grain yield of rice cultivars mainly because of low pollen viability and spikelet fertility. The effects of high temperature on the spikelet fertility and grain filling varied among cultivars and the growth stages of plant when exposed to the high temperature stress. Under high temperature stress, the tolerant cultivar displays higher cell membrane stability, less accumulation of osmolytes, more antioxidant enzyme activities, and higher pollen viability and spikelet fertility than the susceptible cultivars. In the present work, soil application of boron was effective in reducing the negative effects of high temperature both at vegetative and reproductive stages. Application of B results into higher grain yield under both ambient and high temperature condition over control for all the three cultivars; however, more increase was observed for the susceptible cultivar over the tolerant one. The results suggest

  19. Infrared thermometry: a remote sensing technique for predicting yield in water-stressed cotton

    International Nuclear Information System (INIS)

    Pinter, P.J.; Fry, K.E.; Guinn, G.; Mauney, J.R.

    1983-01-01

    A crop water stress index (CWSI) was derived from air temperatures, air vapor pressure deficits and the midday radiant leaf temperatures of cotton plants that were exposed to different early-season irrigation treatments at Phoenix, AZ, U.S.A. To calculate the CWSI, an infrared thermometer was used to measure leaf temperatures which were then scaled relative to minimum and maximum temperatures expected for no-stress (CWSI=0) and extreme drought-stress conditions (CWSI=1). Results showed the CWSI behaved as expected, dropping to low levels following an irrigation and increasing gradually as the cotton plants depleted soil moisture reserves. The final yield of seed cotton was significantly inversely correlated with the average CWSI observed over the interval from the appearance of the first square until two weeks following the final irrigation

  20. Effect of Filter Cake on Morphophysiological and Yield of Sweet Corn Under Late Season Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    S. A. Siadat

    2015-06-01

    Full Text Available In order to investigate the effect of Filter Cake application on some morpho-physiological characteristics and yield of sweet corn (Zea mays var saccharata under different irrigation regimes, an experiment was conducted in Ramin Agriculture and Natural Resources University, Khuzestan, in 2012. The experiment was arranged in split-plot design in RCBD (Completely Randomized Block Design with three replications. Treatments were drought stress (irrigation after 25, 50 and 75% depletion of available water content in main plots and Filter Cake (0, 10, 20 and 30 tonha-1 arranged in sub-plots. Results showed that drought stress increased electrolyte leakage (EL and proline content (PC while height of plant, relative water content (RWC, chlorophyll stability index and ear and grain yield were decreased. The intensive drought stress had the greatest effect on EL and PC (54% increase, and decreased ear and grain yield by21 and 37% compared to control, respectively. Application of filter cake on non-stress condition increased height of plant and economic yield. But Filter Cake in intensive stress reduced RWC and yield and increased EL compared to control. Also, the application of 30 tonha-1 of Filter Cake in intensive stress condition decreased ear and grain yield by 14.5 and 10.7% respectively. Thus, positive effect of Filter Cake application was clear on non-stress condition, but on drought stress condition it decreased the economic yield.

  1. The rising motion of spheres in structured fluids with yield stress

    Science.gov (United States)

    Mirzaagha, S.; Pasquino, R.; Iuliano, E.; D'Avino, G.; Zonfrilli, F.; Guida, V.; Grizzuti, N.

    2017-09-01

    The rising of spherical bodies in structured fluids with yield stress is studied. The system is a suspension of hydrogenated castor oil colloidal fibers in a surfactant micellar solution. The fiber network confers to the fluid a viscoelastic behavior, with a well-defined yield stress, which increases with increasing fiber concentration. Various fluids with different fiber contents are prepared and rheologically characterized. A home-made time-lapse photography setup is used to monitor the time evolution position of the spherical particles, and the rising motion of both hollow spheres and air bubbles, in the diameter range 65-550 μm, is measured. The experiments last as long as several weeks, corresponding to significantly low measured velocities. Finite element simulations are performed to support the experimental data, assuming both interfacial slip and no slip conditions. The fluid dynamic phenomenon is studied and discussed in terms of dimensionless numbers, such as yield ratio, Bingham number, and Stokes drag coefficient. The results are novel for the system (suspending medium and hollow spheres) and for the covered Bingham number range, which is extended over three orders of magnitude in comparison with already available literature results. Our values provide quantitative data of the mechanical properties (i.e., yield stress value) at very low shear rates, in a prohibitive range for a traditional rheometer, and agree with the macroscopic rheological response. Moreover, the important role of the power law index n of the Herschel-Bulkley model, used to fit the data, has been highlighted. Our results, based on a Bingham-like fluid, are compared with the experimental data already available with Carbopol, treated as a Herschel Bulkley fluid with n = 0.5. The results could have important implications in the fabric and personal care detergency, a technological area where many fluids have composition and show rheological properties similar to those considered in the

  2. Effect of Mulch and Water Stress on Some Physiological Traits, Yield Components and Grain Yield of Red Kidney bean (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    R Amini

    2016-02-01

    Full Text Available Introduction Water use in agricultural production as one of the most important environmental factors affecting plant growth and development, especially in arid and semi-arid climatic conditions of Iran is of special importance (21. One of the ways of alleviating water scarcity is by enhancing its use efficiency or productivity. Improving water use efficiency in arid and semi-arid areas depends on effective conservation of moisture and efficient use of limited water. Mulching is one of the management practices for increasing water use efficiency (WUE . Straw mulch is commonly used as mulch. Straw mulching has potential for increasing soil water storage (16. Mulches modify the microclimate and growing conditions of crops (16, conserve more water and increase water use efficiency (34. Red kidney bean (Phaseolus vulgaris L. is the most important food legume (25 and is an important source of proteins and minerals (28. The majority of red kidney bean production is under drought conditions, and thus yield reductions due to drought are very common (29. This research was carried out to evaluate the effect of wheat straw mulch and water stress on physiological traits, yield components and grain yield of red kidney bean cultivars. Materials and Methods A field experiment was conducted in 2012 at the Research Farm of the Faculty of Agriculture, University of Tabriz, Iran (latitude 38°05_N, longitude 46°17_E, altitude 1360 m above sea level. In order to investigate the effect of mulch on grain yield and yield components of red kidney bean (Phaseolus vulgaris L. cultivars at different water stress treatments, a factorial experiment was conducted based on RCB design with three replications. The factors were including water stress treatment (I1 and I2, irrigation after 60 and 120 mm evaporation from class A pan, respectively; mulch application at two levels (M1: (no mulch and M2: 2 ton ha-1 wheat straw mulch and red kidney bean cultivars including Akhtar and

  3. Large particles increase viscosity and yield stress of pig cecal contents without changing basic viscoelastic properties.

    Science.gov (United States)

    Takahashi, Toru; Sakata, Takashi

    2002-05-01

    The viscosity of gut contents should influence digestion and absorption. Earlier investigators measured the viscosity of intestinal contents after the removal of solid particles. However, we previously found that removal of solid particles from pig cecal contents dramatically lowered the viscosity of the contents. Accordingly, we examined the contribution of large solid particles to viscoelastic parameters of gut contents in the present study. We removed large particles from pig cecal contents by filtration through surgical gauze. Then, we reconstructed the cecal contents by returning all, one half or none of the original amount of the large particles to the filtrate. We measured the viscosity, shear stress and shear rate of these reconstructed cecal contents using a tube-flow viscometer. The coefficient of viscosity was larger when the large-particle content was higher (P Bingham plastic nature irrespective of large-particle content. We calculated the yield stress of these fluids assuming that the fluids behave as Bingham plastic. The yield stress of the cecal contents was greater (P Bingham plastic characteristics to pig cecal contents.

  4. Combining Ability of Pod Yield and Related Traits of Groundnut (Arachis hypogaea L. under Salinity Stress

    Directory of Open Access Journals (Sweden)

    Md. Abul Kalam Azad

    2014-01-01

    Full Text Available A study was performed using 6×6 F1 diallel population without reciprocals to assess the mode of inheritance of pod yield and related traits in groundnut with imposed salinity stress. Heterosis was found for pod number and yield. Data on general and specific combining ability (gca and sca indicated additive and nonadditive gene actions. The gca: sca ratios were much less than unity suggesting predominant role of nonadditive gene effects. Cultivars “Binachinabadam-2” and “Dacca-1” and mutant M6/25/64-82 had the highest, second highest, and third highest pod number, as well as gca values, respectively. These two cultivars and another mutant M6/15/70-19 also had the highest, second highest, and third highest pod yield, as well as gca values, respectively. Therefore, “Dacca-1”, “Binachinabadam-2”, M6/25/64-82, and M6/15/70-19 could be used as source of salinity tolerance. Cross combinations showing high sca effects arising from parents with high and low gca values for any trait indicate the influence of nonadditive genes on their expression. Parents of these crosses can be used for biparental mating or reciprocal recurrent selection for developing high yielding varieties. Crosses with high sca effects having both parents with good gca effects could be exploited by pedigree breeding to get transgressive segregants.

  5. Traits in Spring Wheat Cultivars Associated with Yield Loss Caused by a Heat Stress Episode after Anthesis

    DEFF Research Database (Denmark)

    Vignjevic, Marija; Wang, Xiao; Olesen, Jørgen E

    2015-01-01

    with heat tolerance. Fifteen spring wheat (Triticum aestivum L.) cultivars were grown in pots under semifield conditions, and heat stress (35/26 °C) and control treatments (20/12 °C) were applied in growth chambers for 5 days starting 14 days after flowering. The heat stress treatment reduced final yield...... in the grain-filling period was negatively correlated with grain nitrogen yield (r = −0.60). A positive correlation (r = 0.73) was found between the treatment effect on green leaf area (GLA) and the reduction in yield resulting from heat stress. The amount of stem water-soluble carbohydrates (WSC...

  6. Postpartum endocrine activities, metabolic attributes and milk yield are influenced by thermal stress in crossbred dairy cows.

    Science.gov (United States)

    Ihsanullah; Qureshi, Muhammad Subhan; Suhail, Syed Muhammad; Akhtar, Sohail; Khan, Rifat Ullah

    2017-09-01

    This study was conducted on 30 freshly parturated multiparous crossbred dairy cows possessing three levels of Holstein Frisian genetic makeup (62.5, 75.0, and 87.5%). Data on temperature humidity index (THI) were classified into comfortable (≤ 71), mild stress (72-79), moderate stress (80-89), and stressful (≥90) zone. Results showed that serum cortisol concentration increased significantly (P stressful condition irrespective of genetic makeup compared to the other zones. Daily milk yield (DMY) was significantly (P stressful condition. Triglyceride was significantly higher in cows with genetic makeup 87.5% compared to the others, while total serum protein was significantly (P stressful conditions. The mean concentration of cortisol and protein increased linearly from comfort to the stressful condition, while mean serum triglyceride, glucose, progesterone (P 4 ), and luteinizing hormone (LH) decreased by moving from comfort to stressful conditions. Results also indicated that higher cortisol level in higher grade crossbred cows was adversely associated with LH concentration and milk yield under thermal stress conditions. Greater triglyceride in high-grade crossbred (87.5%) cows indicates higher fat mobilization reflecting a negative energy balance. We concluded that heat stress increased blood cortisol and protein, and reduced milk yield in dairy cows irresptive of the genetic makeup. In addition, there was no significant difference in blood metabolites and daily milk yield in the different levels of genetic makeup cows.

  7. Postpartum endocrine activities, metabolic attributes and milk yield are influenced by thermal stress in crossbred dairy cows

    Science.gov (United States)

    Ihsanullah; Qureshi, Muhammad Subhan; Suhail, Syed Muhammad; Akhtar, Sohail; Khan, Rifat Ullah

    2017-09-01

    This study was conducted on 30 freshly parturated multiparous crossbred dairy cows possessing three levels of Holstein Frisian genetic makeup (62.5, 75.0, and 87.5%). Data on temperature humidity index (THI) were classified into comfortable (≤ 71), mild stress (72-79), moderate stress (80-89), and stressful (≥90) zone. Results showed that serum cortisol concentration increased significantly ( P cows during stressful condition irrespective of genetic makeup compared to the other zones. Daily milk yield (DMY) was significantly ( P cows during stressful condition. Triglyceride was significantly higher in cows with genetic makeup 87.5% compared to the others, while total serum protein was significantly ( P cows during both moderate and stressful conditions. The mean concentration of cortisol and protein increased linearly from comfort to the stressful condition, while mean serum triglyceride, glucose, progesterone (P4), and luteinizing hormone (LH) decreased by moving from comfort to stressful conditions. Results also indicated that higher cortisol level in higher grade crossbred cows was adversely associated with LH concentration and milk yield under thermal stress conditions. Greater triglyceride in high-grade crossbred (87.5%) cows indicates higher fat mobilization reflecting a negative energy balance. We concluded that heat stress increased blood cortisol and protein, and reduced milk yield in dairy cows irresptive of the genetic makeup. In addition, there was no significant difference in blood metabolites and daily milk yield in the different levels of genetic makeup cows.

  8. Effects of Saline and Sodic Stress on Yield and Fatty Acid Profile in Sunflower Seeds

    Directory of Open Access Journals (Sweden)

    Giovanna Cucci

    2007-03-01

    Full Text Available Among the objectives concerned in this research, much importance has been attached to the assessment of the influence of soil type, irrigation water quality and leaching requirement on the production and composition in fatty acids of sunflower oil. The trial was run in 2001 on a sunflower crop (cv. HS 90 grown in cylindrical pots at the Campus of Bari University (Italy. 36 treatments obtained from the factorial combination of two clay soils with nine types of brackish water and two leaching fractions (10 and 20% were compared. The nine types of irrigation water were obtained by dissolving the proper amounts of NaCl and CaCl2 in de-ionized water, according to the factorial combination of three salt concentration levels (0.01, 0.032 and 0.064 M with three sodium levels (SAR = 5, 15 and 45. At ripening the main yield traits, oil yield and acid composition of seeds were analysed. At the highest salinity level about 70% yield reduction, in terms of seeds per plant was observed. The oil yield and the final acid composition of seeds were significantly affected by soil type, leaching requirement, salinity and the SAR levels of irrigation water. A progressive decline in oil yield was recorded as the salt concentration and sodium level of irrigation solutions increased. As to the fatty acid composition, a gradual increase in oleic and linolenic acid content and a corresponding decrease in the other fatty acids were found as the salinity and sodium levels of irrigation water increased. The oleic/linoleic acid ratio too increased as the salinity increased. The salt and sodium-induced stresses of irrigation water reduced the seed and oil yields while still favouring a progressive increase in the oleic acid content and a slight decrease of linoleic, palmitic and stearic acids, thus improving oil quality. The results point out both the influence of the soil and the positive effect of sodium and salt stress and of the leaching fraction on the food quality of

  9. Effects of Saline and Sodic Stress on Yield and Fatty Acid Profile in Sunflower Seeds

    Directory of Open Access Journals (Sweden)

    Emanuele Tarantino

    2011-02-01

    Full Text Available Among the objectives concerned in this research, much importance has been attached to the assessment of the influence of soil type, irrigation water quality and leaching requirement on the production and composition in fatty acids of sunflower oil. The trial was run in 2001 on a sunflower crop (cv. HS 90 grown in cylindrical pots at the Campus of Bari University (Italy. 36 treatments obtained from the factorial combination of two clay soils with nine types of brackish water and two leaching fractions (10 and 20% were compared. The nine types of irrigation water were obtained by dissolving the proper amounts of NaCl and CaCl2 in de-ionized water, according to the factorial combination of three salt concentration levels (0.01, 0.032 and 0.064 M with three sodium levels (SAR = 5, 15 and 45. At ripening the main yield traits, oil yield and acid composition of seeds were analysed. At the highest salinity level about 70% yield reduction, in terms of seeds per plant was observed. The oil yield and the final acid composition of seeds were significantly affected by soil type, leaching requirement, salinity and the SAR levels of irrigation water. A progressive decline in oil yield was recorded as the salt concentration and sodium level of irrigation solutions increased. As to the fatty acid composition, a gradual increase in oleic and linolenic acid content and a corresponding decrease in the other fatty acids were found as the salinity and sodium levels of irrigation water increased. The oleic/linoleic acid ratio too increased as the salinity increased. The salt and sodium-induced stresses of irrigation water reduced the seed and oil yields while still favouring a progressive increase in the oleic acid content and a slight decrease of linoleic, palmitic and stearic acids, thus improving oil quality. The results point out both the influence of the soil and the positive effect of sodium and salt stress and of the leaching fraction on the food quality of

  10. Effect of water stress and harvesting stages on quantitative and qualitative yields of coriander (Coriandrum sativum L.

    Directory of Open Access Journals (Sweden)

    A. Ahmadian

    2016-05-01

    Full Text Available In order to study the effect of drought stress and harvesting stages on quantitative and qualitative yields of Coriander (Coriandrum sativum L. this experiment was conducted on split plot based on a randomized completely block design with 3 replications in Torbat-e Heydariyeh University, Iran, during growing season of 2010-2011. Treatments were drought stress (in three levels no stress: control and irrigation in 60 and 30 percentage of FC as main plots and harvesting times (in 3 levels consist of: before flowering, flowering and after flowering as sub plots. Results showed that drought stress and harvesting stages had significant affected on leaf number, height, number of stem, wet and dry weight of plant, SPAD, proline content, carbohydrate content, essential oil yield and percentage and components of essential oil of coriander. Increasing water stress decreased yield and its components while enhanced proline and carbohydrate contents. Maximum of essential oil and its main components (linalool, alpha pentene, gamma terpinene, geranial acetate and camphor were in low stress that had significant difference with other stress treatments. Delaying in harvest enhanced yield and its components and essential oil percentage. Proline content had no significant difference between flowering and after flowering stages. Therefore, we can suggest low stress of water and harvest at after flowering stage to get maximum of yield.

  11. The Bree problem with different yield stresses on-load and off-load and application to creep ratcheting

    International Nuclear Information System (INIS)

    Bradford, R.A.W.; Ure, J.; Chen, H.F.

    2014-01-01

    The ratchet boundaries and ratchet strains are derived for the Bree problem and an elastic-perfectly plastic material with different yield stresses on-load and off-load. The Bree problem consists of a constant uniaxial primary membrane stress and a cycling thermal bending stress. The ratchet problem with differing yield stresses is also solved for a modified loading in which both the primary membrane and thermal bending stresses cycle in-phase. The analytic solutions for the ratchet boundaries are compared with the results of deploying the linear matching method (LMM) and excellent agreement is found. Whilst these results are of potential utility for purely elastic–plastic behaviour, since yield stresses will often differ at the two ends of the cycle, the solution is also proposed as a means of assessing creep ratcheting via a creep ductility exhaustion approach. -- Highlights: • The Bree problem is solved for differing yield stresses on and off load. • The modified Bree problem with cycling primary load is also solved. • These solutions can be applied to creep ratcheting using a pseudo-yield stress

  12. Effect of yield stress matching on ductile fracture behavior of girth welds for X line pipe

    Energy Technology Data Exchange (ETDEWEB)

    Motohashi, Hiroyuki; Hagiwara, Naoto [Tokyo Gas Co., Ltd. (Japan)

    2005-07-01

    This paper describes the effects of yield stress matching on the ductile fracture behavior of girth welded joints for X linepipes. Three welded joints were made on an X line pipe using several consumables to obtain about a 20% overmatched, even matched and about a 20% under matched weld metal. For these three welded joints, curved wide plate tensile tests were then conducted with a surface notch in the weld metal. To determine the ductile crack initiation from the surface notch, these tests employed a direct-current electric potential (d-c E P) method. Crack opening displacement, gauge length strain and local strain adjacent to the surface notch were also measured. The ductile crack initiation was successfully detected using the d-c E P method. The yield stress matching significantly affected the ductile crack initiation and fracture behavior, that is, the overmatched welded joint had a higher resistance to ductile fracture than that of the under matched welded joint. The allowable strength matching level was determined from the relationship between the strength matching and the gauge length strain at the ductile crack initiation detected using the d-c E P method. (author)

  13. The transverse mobility of yield-stress fluids in fibrous media

    Science.gov (United States)

    Shahsavari, Setareh; McKinley, Gareth H.

    2015-11-01

    The pressure-drop/flow-rate relationship for fluids that exhibit a yield stress and a shear dependent viscosity flowing through fibrous media is studied numerically. The Cauchy momentum equation along with the Bingham or Herschel-Bulkley constitutive equations are solved for flow transverse to a periodic array of fibers and systematic parametric studies are used to understand the individual roles of geometrical characteristics and fluid rheological properties. We develop a scaling model to predict the fluid mobility as a function of the medium porosity and the Bingham number. In addition, using this scaling model we estimate the width of the unyielded region between two adjacent fibers. Numerical computations are combined with the scaling model to obtain a criterion for the critical pressure gradient required to drive flow. Variations in the size of the yielded zones, the velocity profiles and the resulting stress fields are investigated for the limiting cases of (i) densely packed fiber arrays and (ii) very sparsely distributed fibers, and the hydrodynamic transition between these configurations is investigated. While this work focuses on the flow of inelastic fluids, the methodology can be extended to consider more complex rheology such as flow of elasto-visco-plastic fluids.

  14. Response of Barley Double Haploid Lines to the Grain Yield and Morphological Traits under Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    Maroof Khalily

    2017-04-01

    Full Text Available To study the relationships of grain yield and some of agro-morphological traits in 40 doubled haploid (DH lines along with parental and three check genotypes in a randomized complete block design with two replications under two water regimes (normal and stress were evaluated during 2011-2012 and 2012-2013 growing seasons. Combined analysis of variance showed significant difference for all the traits in terms of the year, water regimes, lines, and and line × year. Comparison of group means, between non-stress and stress conditions, showed that DH lines had the lowest reduction percentage for the number of grains per spike, thousand grain weight, grain yield and biological yield as opposed to check genotypes. The correlation between grain yield with biological yield, harvest index, thousand grain weight, and hectoliter of kernel weight in both conditions, were highly significant and positive. Based on stepwise regression the peduncle length, number of seeds per spike, thousand seed weight, and hectoliter of kernel weight had important effect on increasing seed yield. The result of path analysis showed that these traits had the highest direct effect on grain yield. Based on mean comparisons of morphological characters as well as STI and GMP indices it can be concluded that lines No.11, 13, 14, 24, 29, 30, 35 and 39 were distinguished to be desirable lines for grain yield and their related traits and also tolerant lines in terms of response to drought stress conditions.

  15. Evaluation Physiological Characteristics and Grain Yield Canola Cultivars under end Seasonal Drought Stress in Weather Condition of Ahvaz

    Directory of Open Access Journals (Sweden)

    A Seyed Ahmadi

    2015-07-01

    Full Text Available To evaluate canola cultivars response to physiological characteristics and grain yield end seasonal drought stress in weather condition of Ahvaz, farm experiments were done at research farm of Khuzestan agriculture and natural resources center. During 2007-2008 and 2008-2009 crop years. Farm test comprised drought stress was done as split plot form with randomize complete block design with four replication, treatments consist of drought stress (main factor including 50, 60 and 70 percent of water use content, which was applied from early heading stage until physiological maturity, and three spring canola cultivar including Shirali, Hayola 401 and R.G.S. were considered as sub plots. Measurements include biological yield, grain yield, harvesting index, number of pod per plant 1000 grain weight, number of grain in pod, plant height, and stem diameter, oil and protein percentage. Results showed that drought stress reduced significantly grain yield, biological yield, harvest index and the average of reduction of them during 2 years for per unit reduce moisture from 50% to 70% were 2, 1.35, and 0.81 percent, respectively. During two years, 1000 grain weight, number of pods per plant and number of grain per pod reduced 27, 36 and 20 percent, respectively. Terminal Drought stress reduced significantly plant height, stem diameter, stem number per plant and pod length, this reduced were 12, 46, 36 and 14 percent, respectively. Stem diameter, and stem number per plant reduced more than other characteristics. In this study oil grain decreased 12 % and protein grain increased 18.5% but oil and protein yield decreased 44.9% and 27.1% respectively..Finally, in weather condition of Khuzestan, terminal drought stress on February and March in which has simultaneous with early flowering stage and filling seed, significantly, reduced yield and compounded yield and affects on stem growth and qualities oil and protein negatively. Therefore, with irrigation

  16. The Effects of Drought Stress on Yield, Yield Components and Anti-oxidant of Two Garlic (Allium sativum L. Ecotypes with Different Planting Densities

    Directory of Open Access Journals (Sweden)

    shiva akbari

    2016-07-01

    Full Text Available Introduction Drought stress reduces plant growth by affecting various physiological and biochemical processes, such as photosynthesis, respiration, translocation, ion uptake, carbohydrates, nutrient metabolism and growth promoters. Garlic (Allium sativum L. is an annual bulb crop that has been cultivated since ancient times and was used as a spice and condiment for many centuries. Garlic is an important plant because of its pharmaceutical properties. The optimum yield of this bulb crop depends on well-managed irrigation, fertilization and cultivation practices. In the final and middle stages of growth, garlic is sensitive to water stress and low irrigation is unsuitable in these stages. This experiment was established to study the influence of drought stress and planting density on yield and its components and the non-enzymatic anti-oxidant content of two different garlic ecotypes. Materials and methods This study was conducted in 2011-2012 in a farmland at the south east of Semnan city. The experimental layout was a split-plot factorial with a randomized complete block design with three replications. The treatments were comprised of three factors: irrigation rates (60%, 80% and 100% of estimated crop evapotranspiration (ETC as the main plot and the factorial combination of three levels of planting density (30, 40 and 50 plants.m-2 and two ecotypes (Tabas and Toroud as the sub-plots. To estimate the crop water requirement, different meteorological parameters were collected from Semnan weather station and were used based on FAO-56 water irrigation calculation instructions. After harvesting, ten garlic plants were sampled randomly in each plot and bulb yield components were measured. To calculate the leaves anti-oxidant content, DPPH method was used. The statistical significances of mean values were assessed by analysis of variance and LSD tests at p≤0.05. All calculations were performed using SAS and Mstat-C softwares. Results and discussion

  17. Influence of oxidative stress and grains on sclerotial biomass and carotenoid yield of Penicillium sp. PT95.

    Science.gov (United States)

    Chen, Shu-Jun; Wang, Qi; Han, Jian-Rong

    2010-08-01

    Oxidative stress and grains were evaluated for carotenoid production by solid-state fermentation using Penicillium sp. PT95. When the fungus was grown at high oxidative stress, its sclerotial biomass and carotenoid content in sclerotia increased significantly with respect to low oxidative stress (P < 0.01). High oxidative stress also caused a statistically significant increase in carotenoid yield as compared with low oxidative stress (P < 0.01). Both the sclerotial biomass and the amount of carotenoid accumulated in sclerotia of strain PT95 were strongly dependent on the grain medium used. Among the grain media tested under high oxidative stress, buckwheat medium gave the highest content of carotenoid in sclerotia (828 microg/g dry sclerotia), millet medium gave respectively the highest sclerotial biomass (12.69 g/100 g grain) and carotenoid yield (10.152 mg/100 g grain). Copyright 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  18. Effects of shade and drought stress on soybean hormones and yield ...

    African Journals Online (AJOL)

    Jane

    2011-10-24

    Oct 24, 2011 ... hormone concentrations, main-stem and branch yield response to the combination of shade and drought were studied ... yield primarily by reducing branch growth and branch seed yield per ..... deficit soybean. Yield decrease ...

  19. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Science.gov (United States)

    Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Liu, Yang; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem B.; Zhang, Lizhen

    2017-08-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root / shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season) and to mitigate drought risk in dry-land agriculture.

  20. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Directory of Open Access Journals (Sweden)

    Q. Cai

    2017-08-01

    Full Text Available A large yield gap exists in rain-fed maize (Zea mays L. production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU and water use efficiency (WUE. Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root ∕ shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season and to mitigate drought risk in dry-land agriculture.

  1. Do maize models capture the impacts of heat and drought stresses on yield? Using algorithm ensembles to identify successful approaches.

    Science.gov (United States)

    Jin, Zhenong; Zhuang, Qianlai; Tan, Zeli; Dukes, Jeffrey S; Zheng, Bangyou; Melillo, Jerry M

    2016-09-01

    Stresses from heat and drought are expected to increasingly suppress crop yields, but the degree to which current models can represent these effects is uncertain. Here we evaluate the algorithms that determine impacts of heat and drought stress on maize in 16 major maize models by incorporating these algorithms into a standard model, the Agricultural Production Systems sIMulator (APSIM), and running an ensemble of simulations. Although both daily mean temperature and daylight temperature are common choice of forcing heat stress algorithms, current parameterizations in most models favor the use of daylight temperature even though the algorithm was designed for daily mean temperature. Different drought algorithms (i.e., a function of soil water content, of soil water supply to demand ratio, and of actual to potential transpiration ratio) simulated considerably different patterns of water shortage over the growing season, but nonetheless predicted similar decreases in annual yield. Using the selected combination of algorithms, our simulations show that maize yield reduction was more sensitive to drought stress than to heat stress for the US Midwest since the 1980s, and this pattern will continue under future scenarios; the influence of excessive heat will become increasingly prominent by the late 21st century. Our review of algorithms in 16 crop models suggests that the impacts of heat and drought stress on plant yield can be best described by crop models that: (i) incorporate event-based descriptions of heat and drought stress, (ii) consider the effects of nighttime warming, and (iii) coordinate the interactions among multiple stresses. Our study identifies the proficiency with which different model formulations capture the impacts of heat and drought stress on maize biomass and yield production. The framework presented here can be applied to other modeled processes and used to improve yield predictions of other crops with a wide variety of crop models. © 2016 John

  2. Yield strength, shear stress and toughness of YBCO samples textured by Bridgman technique

    International Nuclear Information System (INIS)

    Roa, J J; Capdevila, X G; Martinez, M; Segarra, M; Jimenez-Pique, E

    2008-01-01

    Mechanical properties of the orthorhombic phase of YBa 2 Cu 3 O 7-δ (Y-123) at room temperature have been investigated at different applied loads using nanoindentation technique. The study was carried out for several monodomains on the (001) planes for textured Bridgman samples with dispersed Y 2 BaCuO 5 (Y-211) particles as pinning centers. The yield strength (σ ys ), shear stress (τ m ) and toughness (K IC ) of Y123/Y211composite was determined at different applied loads. First and second mechanical properties have been calculated though the Hertz equations and the last one with Lawn et al. equations. Finally, the ultra-low imprints obtained by nanoindentation have been correlated with parameters obtained by Field Emission Scanning Electron Microscope (FE-SEM)

  3. A Piston-Rotaxane with Two Potential Stripes: Force Transitions and Yield Stresses

    Directory of Open Access Journals (Sweden)

    Edith M. Sevick

    2013-10-01

    Full Text Available We examine a rod piston-rotaxane system, where the positions of several mobile rings on the axle are controlled by an external force acting on one of the rings. This allows us to access the translational entropy of the rings. For a simple rotaxane molecule with an axle that has uniform ring-axle interactions along its length, the molecule behaves like a miniature piston filled with a one-dimensional ideal gas. We then examine the effect of two stripes on the axle, having different ring-axle interactions with the mobile rings, so that one section is of high energy (repulsive for the rings and another section is of lower energy (or attractive. This kind of rotaxane can exhibit rapid changes in displacement or force, and in particular, this molecule can exhibit a yield stress in which the piston suddenly compresses under a small increase in the applied force.

  4. Static yield stress of a magnetorheological fluid containing Pickering emulsion polymerized Fe2O3/polystyrene composite particles.

    Science.gov (United States)

    Seo, Youngwook P; Kwak, Soonjong; Choi, Hyoung Jin; Seo, Yongsok

    2016-02-01

    The flow behaviors of magnetorheological (MR) suspensions containing Pickering emulsion polymerized Fe2O3/polystyrene (PS) composite particles were reanalyzed using the Seo-Seo model. The experimental shear stress data obtained experimentally from the magnetorheological fluid fit well to the Seo-Seo model, indicating that this model can describe the structural reformation process of the aligned fibers at various shear rates. Unlike the dynamic yield stress obtained from the Cho-Choi-Jhon (CCJ) model, the static yield stresses obtained from the Seo-Seo model exhibit the same quadratic dependence on the magnetic field strength for both pure Fe2O3 particle suspension and Fe2O3/PS particle suspensions, which is in agreement with the predictions of the polarization model. The static yield stress plausibly explains the difference in underlying mechanism of MR fluids. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Combining Earthquake Focal Mechanism Inversion and Coulomb Friction Law to Yield Tectonic Stress Magnitudes in Strike-slip Faulting Regime

    Science.gov (United States)

    Soh, I.; Chang, C.

    2017-12-01

    The techniques for estimating present-day stress states by inverting multiple earthquake focal mechanism solutions (FMS) provide orientations of the three principal stresses and their relative magnitudes. In order to estimate absolute magnitudes of the stresses that are generally required to analyze faulting mechanics, we combine the relative stress magnitude parameter (R-value) derived from the inversion process and the concept of frictional equilibrium of stress state defined by Coulomb friction law. The stress inversion in Korean Peninsula using 152 FMS data (magnitude≥2.5) conducted at regularly spaced grid points yields a consistent strike-slip faulting regime in which the maximum (S1) and the minimum (S3) principal stresses act in horizontal planes (with an S1 azimuth in ENE-WSW) and the intermediate principal stress (S2) close to vertical. However, R-value varies from 0.28 to 0.75 depending on locations, systematically increasing eastward. Based on the assumptions that the vertical stress is lithostatic, pore pressure is hydrostatic, and the maximum differential stress (S1-S3) is limited by Byerlee's friction of optimally oriented faults for slip, we estimate absolute magnitudes of the two horizontal principal stresses using R-value. As R-value increases, so do the magnitudes of the horizontal stresses. Our estimation of the stress magnitudes shows that the maximum horizontal principal stress (S1) normalized by vertical stress tends to increase from 1.3 in the west to 1.8 in the east. The estimated variation of stress magnitudes is compatible with distinct clustering of faulting types in different regions. Normal faulting events are densely populated in the west region where the horizontal stress is relatively low, whereas numerous reverse faulting events prevail in the east offshore where the horizontal stress is relatively high. Such a characteristic distribution of distinct faulting types in different regions can only be explained in terms of stress

  6. Residual effects of biochar on improving growth, physiology and yield of wheat under salt stress

    DEFF Research Database (Denmark)

    Akhtar, Saqib Saleem; Andersen, Mathias Neumann; Liu, Fulai

    2015-01-01

    Salinity is one of the major threats to global food security. Biochar amendment could alleviate the negative impacts of salt stress in crop in the season. However, its long-term residual effect on reducing Na+ uptake in latter crops remains unknown. A pot experiment with wheat was conducted...... in a greenhouse. The soil used was from an earlier experiment on potato where the plants were irrigated with tap water (S0), 25 mM (S1) and 50 mM (S2) NaCl solutions and with 0 and 5% (w/w) biochar amendment. At onset of the experiment, three different EC levels at S0, S1 and S2 were established in the non...... by transient Na+ binding due to its high adsorption capacity, decreasing osmotic stress by enhancing soil moisture content, and by releasing mineral nutrients (particularly K+, Ca++, Mg++) into the soil solution. Growth, physiology and yield of wheat were affected positively with biochar amendment...

  7. Effect of Filter Cake on Physiological Traits and Ear Yield of Sweet Corn under Late Drought Stress Condition

    Directory of Open Access Journals (Sweden)

    aziz karmollachaab

    2017-10-01

    Full Text Available Introduction Environmental stresses are one of the main causes of severe yield reductions. Drought is still a serious agronomic problem and also one of the most important factors contributing to crop yield loss in arid and semi-arid areas in the world. Filter Cake is a byproduct of sugarcane industry and experiments on corn showed that the use of 20 tons per hectare Filter Cake increases crop productivity, total amount of dry matter, protein and forage yield compared with the control. Materials and methods This experiment was conducted at the Research Station of the Ramin Agricultural University of Khuzestan in 2012. The experiment was done as a split plot based on randomized complete block design with three replications. Drought stress at the end of the growth period in three levels, non-stress, mild and severe drought stress, respectively irrigated after 25, 50 and 75% depletion of available water, and was considered as the main factor. Drought stress was applied in early stage of the male inflorescence of plants to maturity for 35 days, due to the critical stage of the plant in late spring. Soil moisture was determined by gravimetric method. Different doses of Filter Cake (0, 10, 20 and 30 tons per hectare were considered as subplot factor and was added to the soil two days before the seeding. The final harvest as green corn was performed in the first phase of dough by hand in three times and two midfields of each subplot was considered as the margin of half a meter for each side. Finally, the data were analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at probability level of 5%. Results and discussion In non-stress conditions, Filter Cake is significantly increased plant height, So the amounts of 20 and 30 tons per hectare increased by 11.7% and 10.1% of the plant’s height, respectively, but the use of 10 tons of Filter Cake did not have a significant effect on it. In severe stress conditions, the use of

  8. Growth and yield response of wheat varieties to water stress at booting and anthesis stages of development

    International Nuclear Information System (INIS)

    Khakwani, A.A.; Abid, M.

    2012-01-01

    Plants of 6 bread wheat varieties (Damani, Hashim-8, Gomal-8, DN-73, Zam-04 and Dera-98) were subjected to 2 treatments i.e., control treatment (100% field capacity) and stressed treatment (20 days water stress was given during booting stage and 20 days water stress after anthesis). The findings revealed highly significant differences among means of wheat varieties in all physiological and yield traits. Almost all varieties showed their best adaptation under stressed environment however Hashim-8 and Zam-04 behaved exclusively and indicated higher relative water content (RWC), mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI) whereas stress susceptibility index (SSI) and tolerance (TOL) was estimated at its lowest, as these traits are recognised beneficial drought tolerance indicators for selection of a stress tolerant variety. Similarly, total grain yield per plant, biological yield per plant and harvest index was also higher in the same wheat varieties that put them as good candidates for selection criteria in wheat breeding program for drought resistant. (author)

  9. Genotypic Correlation and Path Analysis of Some Traits related to Oil Yield and Grain Yield in Canola (Brassica napus L. under Non-stress and Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Ismaili

    2017-03-01

    Full Text Available Introduction Obtaining varieties with acceptable yield and tolerant to different arid and semi-arid climate condition of Iran is an important goal in canola breeding programs. Selection of genotypes base on one or more traits without regarding to correlation between them, could biases the expected results. Therefore, identifying of genetic correlation among traits especially in environmental stress condition is very important. The use of genotypic correlation helps evaluating the magnitude and direction of associations between characters facilitating the application of indirect selection, because genetic changes in a given trait may change other traits, leading to faster and larger genetic gains in plant breeding programs. Therefore, the selection for another trait may result in indirect response in the low heritable trait, provided the following conditions are satisfied: the genetic correlation between them is substantial, and the heritability of the secondary trait is greater than that of the primary trait. The purpose of this study was estimating the total genotypic variability, genotypic correlations, and path analysis among some important traits for selection criteria for improving seed and oil yield in canola under water deficit stress condition. Materials and Methods For evaluation of genetic correlation among traits and identifying important affecting traits on grain yield and oil yield in canola genotypes, an experiment was conducted based on a randomized complete blocks design with three replications in two different conditions of water deficit (stress and non-stress. Different traits were measured including seed yield, 1000-seed weight, number of seeds per pod, number of pods per plant, silique length, oil content, days to maturity, protein content, plant height and water use efficiency. Genotypic and phenotypic correlation coefficients were calculated for ten characters during growing seasons. The genotypic correlation coefficients

  10. Feeding sustains photosynthetic quantum yield of a scleractinian coral during thermal stress.

    Science.gov (United States)

    Borell, Esther M; Bischof, Kai

    2008-10-01

    Thermal resistance of the coral-zooxanthellae symbiosis has been associated with chronic photoinhibition, increased antioxidant activity and protein repair involving high demands of nitrogen and energy. While the relative importance of heterotrophy as a source of nutrients and energy for cnidarian hosts, and as a means of nitrogen acquisition for their zooxanthellae, is well documented, the effect of feeding on the thermal sensitivity of the symbiotic association has been so far overlooked. Here we examine the effect of zooplankton feeding versus starvation on the bleaching susceptibility and photosynthetic activity of photosystem II (PSII) of zooxanthellae in the scleractinian coral Stylophora pistillata in response to thermal stress (daily temperature rises of 2-3 degrees C) over 10 days, employing pulse-amplitude-modulated chlorophyll fluorometry. Fed and starved corals displayed a decrease in daily maximum potential quantum yield (F (v)/F (m)) of PSII, effective quantum yield (F/F (m)') and relative electron transport rates over the course of 10 days. However after 10 days of exposure to elevated temperature, F (v)/F (m) of fed corals was still 50-70% higher than F (v)/F (m) of starved corals. Starved corals showed strong signs of chronic photoinhibition, which was reflected in a significant decline in nocturnal recovery rates of PSII relative to fed corals. This was paralleled by the progressive inability to dissipate excess excitation energy via non-photochemical quenching (NPQ). After 10 days, NPQ of starved corals had decreased by about 80% relative to fed corals. Feeding treatment had no significant effect on chlorophyll a and c (2) concentrations and zooxanthellae densities, but the mitotic indices were significantly lower in starved than in fed corals. Collectively the results indicate that exogenous food may reduce the photophysiological damage of zooxanthellae that typically leads to bleaching and could therefore play an important role in mediating the

  11. Effect of Water Stress and Sulfur Fertilizer on Grain Yield, Chlorophyll and Nutrient Status of Black Cumin (Nigella Sativa L.

    Directory of Open Access Journals (Sweden)

    M. Heidari

    2011-04-01

    Full Text Available In order to study the effects of water stress and different amounts of sulfur fertilizer on grain yield, nutrient status and chlorophyll content in black cumin (Nigella sativa L. a field experiment as split plot design with three replications was conducted at Ghaen city in 2009. Treatments included three levels of irrigation after 50, 100 and 150 mm evaporation from Class A pan as main plot and four levels of sulfur fertilizer including 0, 75, 150 and 225 kg/ha from bentonite-sulfur source as sub-plot. Statistical analysis of the results showed that water stress has significant effect on grain yield and essential oil of black cumin. At the level of 150 mm evaporation from Class A pan, the grain yield decreased by 22.8% and essential oil by 27.6%. Application of 225 kg/ha sulfur fertilizer increased grain yield up to 7.2%. Water stress and sulfur fertilizer treatments had only significant effect on chlorophyll a content. However, water stress decreased chlorophyll a content, but sulfur fertilizer application up to 225 kg/ha increased the content of chlorophyll a. In this study, water stress decreased potassium content in black cumin leaves, but increased the sodium and calcium accumulation. Although application of sulfur fertilizer affected significantly the potassium and magnesium contents in shoots, but did not have significant effect on sodium and calcium contents.

  12. Effects of drought stress and arbuscular mycorrhizal fungi on some morphophysiological traits and yield of savory (Satureja hortensis L.)

    OpenAIRE

    B. Esmaielpour; P. Jalilvand; J. Hadian

    2016-01-01

    Water deficit stress permanent or temporary limits the growth and distribution of natural vegetation and performance of plants more than other environmental factors. In order to investigate the effect of drought stress and mycorrhizal-arbuscular fungi inoculation on the growth and yield of savory (Satureja hortensis L.) a factorial experiment based on completely randomized design were conducted in Research Greenhouse of Horticulture Department of Mohaghegh Ardabili University during 2010. Exp...

  13. Can LENR Energy Gains Exceed 1000?

    Science.gov (United States)

    Nagel, David J.

    2011-03-01

    Energy gain is defined as the energy realized from reactions divided by the energy required to produce those reactions. Low Energy Nuclear Reactions (LENR) have already been measured to significantly exceed the energy gain of 10 projected from ITER,possibly 15 years from now. Electrochemical experiments using the Pd-D system have shown energy gains exceeding 10. Gas phase experiments with the Ni-H system were reported to yield energy gains of over 100. Neither of these reports has been adequately verified or reproduced. However, the question in the title still deserves consideration. If, as thought by many, it is possible to trigger nuclear reactions that yield MeV energies with chemical energies of the order of eV, then the most optimistic expectation is that LENR gains could approach one million. Hence, the very tentative answer to the question above is yes. However, if LENR could be initiated with some energy cost, and then continue to ``burn,'' very high energy gains might be realized. Consider a match and a pile of dry logs. The phenomenon termed ``heat after death'' will be examined to see if it might be the initial evidence for nuclear ``burning.''

  14. Effects of different mycorrhiza species on grain yield, nutrient uptake and oil content of sunflower under water stress

    Directory of Open Access Journals (Sweden)

    Mostafa Heidari

    2014-01-01

    Full Text Available The role of arbuscular mycorrhizal fungi in alleviating water stress is well documented. In order to study the effects of water stress and two different mycorrhiza species on grain yield, nutrient uptake and oil content of sunflower, a field experiment as split plot design with three replications was conducted in the Research Field Station, Zabol University, Zabol, Iran in 2011. Water stress treatments included control as 90% of field capacity (W1, 70% field capacity (W2 and 50% field capacity (W3 assigned to the main plots and two different mycorrhiza species, consisting of M1 = control (without any inoculation, M2 = Glumus mossea and M3 = Glumus etanicatum as sub plots. Results showed that by increasing water stress from control (W1 to W3 treatment, grain yield was significantly decreased. The reduction in the level of W3 was 15.05%. The content of potassium in seeds significantly decreased due to water stress but water stress upto W2 treatment increased the content of phosphorus, nitrogen and oil content of seeds. In between two species of mycorrhiza in sunflower plants, Glumus etanicatum had the highest effect on grain yield and these elements in seeds and increased both.

  15. Effects of inter-varietal diversity, biotic stresses and environmental productivity on grain yield of spring barley variety mixtures

    DEFF Research Database (Denmark)

    Kiær, Lars Pødenphant; Skovgaard, Ib M.; Østergård, Hanne

    2012-01-01

    than their component varieties when accounting also for the general response to environmental productivity. Hence, most mixtures adapted slightly better to environmental productivity and were less sensitive to environmental stress than their component varieties. We conclude that the efficacy of variety...... mixtures may be enhanced by mixing relatively high-yielding varieties differing in responsiveness to environmental productivity.......Varietal seed mixtures tend to increase and stabilize crop yields, yet their application is sparse. Large-scale cultivation of variety mixtures may require a better understanding of how inter-varietal interactions and their interaction with the environment may influence the grain yield of variety...

  16. Increasing influence of heat stress on French maize yields from the 1960s to the 2030s

    Science.gov (United States)

    Hawkins, Ed; Fricker, Thomas E; Challinor, Andrew J; Ferro, Christopher A T; Kit Ho, Chun; Osborne, Tom M

    2013-01-01

    Improved crop yield forecasts could enable more effective adaptation to climate variability and change. Here, we explore how to combine historical observations of crop yields and weather with climate model simulations to produce crop yield projections for decision relevant timescales. Firstly, the effects on historical crop yields of improved technology, precipitation and daily maximum temperatures are modelled empirically, accounting for a nonlinear technology trend and interactions between temperature and precipitation, and applied specifically for a case study of maize in France. The relative importance of precipitation variability for maize yields in France has decreased significantly since the 1960s, likely due to increased irrigation. In addition, heat stress is found to be as important for yield as precipitation since around 2000. A significant reduction in maize yield is found for each day with a maximum temperature above 32 °C, in broad agreement with previous estimates. The recent increase in such hot days has likely contributed to the observed yield stagnation. Furthermore, a general method for producing near-term crop yield projections, based on climate model simulations, is developed and utilized. We use projections of future daily maximum temperatures to assess the likely change in yields due to variations in climate. Importantly, we calibrate the climate model projections using observed data to ensure both reliable temperature mean and daily variability characteristics, and demonstrate that these methods work using retrospective predictions. We conclude that, to offset the projected increased daily maximum temperatures over France, improved technology will need to increase base level yields by 12% to be confident about maintaining current levels of yield for the period 2016–2035; the current rate of yield technology increase is not sufficient to meet this target. PMID:23504849

  17. The Effect of Chemical, Biological and Organic Nutritional Treatments on Sunflowers Yield and Yield Components under the Influence of Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    fatemeh soleymani

    2016-07-01

    Full Text Available Introduction To achieve the higher economic yield of crop plants, supplying enough nutrients to plants is very important. Moreover, nutrient uptakes by plants is influenced by the soil water contents. However, nowadays chemical fertilizer application is important agronomic factor that has significant effects on growth and quantity and quality of final yield, but traditional nutrient management and excessive use of chemical fertilizers may cause the environmental problems such as contamination of soil and water resources, low quality of agricultural products and reduction of soil fertility. These factors have drawn attention to health and ecological sustainable farming systems (Sharma, 2002. In this context, usage of organic and biological products for plant nutrition is considered as one of the solutions to achieve the goals of sustainable agriculture. Materials and methods To evaluate the effect of various feeding systems on yield and yield components of sunflower (Helianthus annuus L. under the influence of water deficit stress, a split-plot experiment based on randomized complete block design with three replications, was carried out in the Agricultural Faculty of Bu-Ali Sina University during the growing season of 2013-2014. Main plots consisted of two irrigation levels: optimum irrigation and deficit irrigation stress (irrigation after 60 and 120 mm evaporation from evaporation pan, class A, respectively and sub-plots included of nine nutrition systems: 1- no bio or chemical fertilizer application, 2- 100% of the recommended chemical fertilizer , 3- vermicompost, 4- phospho nitro kara, 5- vermicompost+ phospho nitro kara, 6- vermicompost+ ½ chemical fertilizer, 7- phospho nitro kara+ ½ chemical fertilizer, 8- vermicompost+ phospho nitro kara+ ½ chemical fertilizer, 9- ½ proposed chemical fertilizer. Phospho-nitro-kara which contains phosphate solubilizing and nitrogen fixing bacteria (Bacillus coagulans, azotobactr chroocuccum and

  18. Effect of Foliar Application of Chelate Iron in Common and Nanoparticles Forms on Yield and Yield Components of Cumin (Cuminum cyminum L. under Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    A Nasiri Dehsorkhi

    2018-05-01

    Full Text Available Introduction Cumin is a member of Apiaceae family and annual plant which is widely cultivated in arid and semi-arid zone. Iran is one of the main producers of this plant. Water deficit is the major limiting factor in crops production. Proper nutrition management under stress conditions could partly help the plant to tolerate different stresses. Various studies were carried out to understand the effect of nanoparticles on the growth of plants. For example, Hong et al. (2005 and Yang et al. (2006 reported that a proper concentration of nano-TiO2 was found to improve the growth of spinach by promoting photosynthesis and nitrogen metabolism. Iran a country with arid and semi-arid climate, always face water deficiency. Thus the aim of this research was investigate the effect of foliar application of chelate iron in common and nanoparticles forms on yield and yield components of cumin (Cuminum cyminum L. under drought stress conditions. Materials and Methods A field experiment was conducted as a split plot in complete randomized block design with three replications in Esfahan city, during the growing season of 2015-2016. Treatments were included three irrigation intervals (5, 10 and 15 days as main plots and Fe foliar application in four levels (control, 2 g L-1 iron chelate, 2 g L-1 Nano-iron chelate, 4 g L-1 iron chelate, 4 g L-1 nano-iron chelate. Foliar application of Fe chelate on leaves was done two times at before and after flowering stage. The plots were 16 m2 with 4 sowing rows, 4 m long. Seeds were placed at 2 to 4 cm depth in each row. All data collected were subjected of analysis of variance (ANOVA using MSTATC software. Significant differences between means refer to the probability level of 0.05 by LSD test. Results and Discussion The results indicated that drought stress decreased the investigated traits significantly but the effect of irrigation by 15 days interval was more than 10 days. Plots which irrigated by 15 days interval showed

  19. Assessing and Exploiting Functional Diversity in Germplasm Pools to Enhance Abiotic Stress Adaptation and Yield in Cereals and Food Legumes

    Science.gov (United States)

    Dwivedi, Sangam L.; Scheben, Armin; Edwards, David; Spillane, Charles; Ortiz, Rodomiro

    2017-01-01

    There is a need to accelerate crop improvement by introducing alleles conferring host plant resistance, abiotic stress adaptation, and high yield potential. Elite cultivars, landraces and wild relatives harbor useful genetic variation that needs to be more easily utilized in plant breeding. We review genome-wide approaches for assessing and identifying alleles associated with desirable agronomic traits in diverse germplasm pools of cereals and legumes. Major quantitative trait loci and single nucleotide polymorphisms (SNPs) associated with desirable agronomic traits have been deployed to enhance crop productivity and resilience. These include alleles associated with variation conferring enhanced photoperiod and flowering traits. Genetic variants in the florigen pathway can provide both environmental flexibility and improved yields. SNPs associated with length of growing season and tolerance to abiotic stresses (precipitation, high temperature) are valuable resources for accelerating breeding for drought-prone environments. Both genomic selection and genome editing can also harness allelic diversity and increase productivity by improving multiple traits, including phenology, plant architecture, yield potential and adaptation to abiotic stresses. Discovering rare alleles and useful haplotypes also provides opportunities to enhance abiotic stress adaptation, while epigenetic variation has potential to enhance abiotic stress adaptation and productivity in crops. By reviewing current knowledge on specific traits and their genetic basis, we highlight recent developments in the understanding of crop functional diversity and identify potential candidate genes for future use. The storage and integration of genetic, genomic and phenotypic information will play an important role in ensuring broad and rapid application of novel genetic discoveries by the plant breeding community. Exploiting alleles for yield-related traits would allow improvement of selection efficiency and

  20. Assessing and Exploiting Functional Diversity in Germplasm Pools to Enhance Abiotic Stress Adaptation and Yield in Cereals and Food Legumes

    Directory of Open Access Journals (Sweden)

    Sangam L. Dwivedi

    2017-08-01

    Full Text Available There is a need to accelerate crop improvement by introducing alleles conferring host plant resistance, abiotic stress adaptation, and high yield potential. Elite cultivars, landraces and wild relatives harbor useful genetic variation that needs to be more easily utilized in plant breeding. We review genome-wide approaches for assessing and identifying alleles associated with desirable agronomic traits in diverse germplasm pools of cereals and legumes. Major quantitative trait loci and single nucleotide polymorphisms (SNPs associated with desirable agronomic traits have been deployed to enhance crop productivity and resilience. These include alleles associated with variation conferring enhanced photoperiod and flowering traits. Genetic variants in the florigen pathway can provide both environmental flexibility and improved yields. SNPs associated with length of growing season and tolerance to abiotic stresses (precipitation, high temperature are valuable resources for accelerating breeding for drought-prone environments. Both genomic selection and genome editing can also harness allelic diversity and increase productivity by improving multiple traits, including phenology, plant architecture, yield potential and adaptation to abiotic stresses. Discovering rare alleles and useful haplotypes also provides opportunities to enhance abiotic stress adaptation, while epigenetic variation has potential to enhance abiotic stress adaptation and productivity in crops. By reviewing current knowledge on specific traits and their genetic basis, we highlight recent developments in the understanding of crop functional diversity and identify potential candidate genes for future use. The storage and integration of genetic, genomic and phenotypic information will play an important role in ensuring broad and rapid application of novel genetic discoveries by the plant breeding community. Exploiting alleles for yield-related traits would allow improvement of selection

  1. A seed preferential heat shock transcription factor from wheat provides abiotic stress tolerance and yield enhancement in transgenic Arabidopsis under heat stress environment.

    Directory of Open Access Journals (Sweden)

    Harsh Chauhan

    Full Text Available Reduction in crop yield and quality due to various abiotic stresses is a worldwide phenomenon. In the present investigation, a heat shock factor (HSF gene expressing preferentially in developing seed tissues of wheat grown under high temperatures was cloned. This newly identified heat shock factor possesses the characteristic domains of class A type plant HSFs and shows high similarity to rice OsHsfA2d, hence named as TaHsfA2d. The transcription factor activity of TaHsfA2d was confirmed through transactivation assay in yeast. Transgenic Arabidopsis plants overexpressing TaHsfA2d not only possess higher tolerance towards high temperature but also showed considerable tolerance to salinity and drought stresses, they also showed higher yield and biomass accumulation under constant heat stress conditions. Analysis of putative target genes of AtHSFA2 through quantitative RT-PCR showed higher and constitutive expression of several abiotic stress responsive genes in transgenic Arabidopsis plants over-expressing TaHsfA2d. Under stress conditions, TaHsfA2d can also functionally complement the T-DNA insertion mutants of AtHsfA2, although partially. These observations suggest that TaHsfA2d may be useful in molecular breeding of crop plants, especially wheat, to improve yield under abiotic stress conditions.

  2. The influence of predeformations and annealings on yield stress and modulus of elongation essentially yttrium doped copper

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Sytin, V.I.; Voevodin, V.N.

    2003-01-01

    The researches results of influence of predeformations and annealings on elastic and plastic characteristics of vacuum melting and yttrium doped copper are given. The interrelation between elastic and plastic characteristics has been shown. It is shown that the yield stress and modulus of elongation essentially depend on predeformations and annealings and they are the structurally sensitive characteristics

  3. Yield Stress Reduction of Radioactive Waste Slurries by Addition of Surfactants

    International Nuclear Information System (INIS)

    MICHAEL, STONE

    2005-01-01

    The Savannah River Site (SRS) and Hanford site are in the process of stabilizing millions of gallons of radioactive waste slurries remaining from production of nuclear materials for the Department of Energy (DOE). The Defense Waste Processing Facility (DWPF) at SRS is currently vitrifying the waste in borosilicate glass while the facilities at the Hanford site are in the design/construction phase. Both processes utilize slurry-fed joule heated melters to vitrify the waste slurries. The rheological properties of the waste slurries limit the total solids content that can be processed by the remote equipment during the pretreatment and melter feed processes. The use of a surface active agent, or surfactant, to increase the solids loading that can be fed to the melters would increase melt rate by reducing the heat load on the melter required to evaporate the water in the feed. The waste slurries are non-Newtonian fluids with rheological properties that were modeled using the Bingham Plastic mod el (this model is typically used by SRNL when studying the DWPF process1).The results illustrate that altering the surface chemistry of the particulates in the waste slurries can lead to a reduction in the yield stress. Dolapix CE64 is an effective surfactant over a wide range of pH values and was effective for all simulants tested. The effectiveness of the additive increased in DWPF simulants as the concentration of the additive was increased. No maxi main effectiveness was observed. Particle size measurements indicate that the additive acted as a flocculant in the DWPF samples and as a dispersant in the RPP samples

  4. Comments on the Dutton-Puls model: Temperature and yield stress dependences of crack growth rate in zirconium alloys

    International Nuclear Information System (INIS)

    Kim, Young S.

    2010-01-01

    Research highlights: → This study shows first that temperature and yield stress dependences of crack growth rate in zirconium alloys can analytically be understood not by the Dutton-Puls model but by Kim's new DHC model. → It is demonstrated that the driving force for DHC is ΔC, not the stress gradient, which is the core of Kim's DHC model. → The Dutton-Puls model reveals the invalidity of Puls' claim that the crack tip solubility would increase to the cooling solvus. - Abstract: This work was prompted by the publication of Puls's recent papers claiming that the Dutton-Puls model is valid enough to explain the stress and temperature dependences of the crack growth rate (CGR) in zirconium alloys. The first version of the Dutton-Puls model shows that the CGR has positive dependences on the concentration difference ΔC, hydrogen diffusivity D H , and the yield strength, and a negative dependence on the applied stress intensity factor K I , which is one of its critical defects. Thus, the Dutton-Puls model claiming that the temperature dependence of CGR is determined by D H C H turns out to be incorrect. Given that ΔC is independent of the stress, it is evident that the driving force for DHC is ΔC, not the stress gradient, corroborating the validity of Kim's model. Furthermore, the predicted activation energy for CGR in a cold-worked Zr-2.5Nb tube disagrees with the measured one for the Zr-2.5Nb tube, showing that the Dutton-Puls model is too defective to explain the temperature dependence of CGR. It is demonstrated that the revised Dutton-Puls model also cannot explain the yield stress dependence of CGR.

  5. Yield stress determines bioprintability of hydrogels based on gelatin-methacryloyl and gellan gum for cartilage bioprinting

    Science.gov (United States)

    Mouser, Vivian H. M.; Melchels, Ferry P.W.; Visser, Jetze; Dhert, Wouter J.A.; Gawlitta, Debby; Malda, Jos

    2016-01-01

    Bioprinting of chondrocyte-laden hydrogels facilitates the fabrication of constructs with controlled organization and shape for e.g. articular cartilage implants. Gelatin-methacryloyl (gelMA) supplemented with gellan gum is a promising bio-ink. However, the rheological properties governing the printing process, and the influence of gellan gum on the mechanical properties and chondrogenesis of the blend, are still unknown. Here, we investigated the suitability of gelMA/gellan for cartilage bioprinting. Multiple concentrations, ranging from 3-25% gelMA with 0-1.5% gellan gum, were evaluated for their printability, defined as the ability to form filaments and to incorporate cells at 15-37°C. To support the printability assessment, yield stress and viscosity of the hydrogels were measured. Stiffness of UV-cured constructs, as well as cartilage-like tissue formation by embedded chondrocytes, were determined in vitro. A large range of gelMA/gellan concentrations were printable with inclusion of cells and formed the bioprinting window. Addition of gellan gum improved filament deposition by inducing yielding behavior, increased construct stiffness, and supported chondrogenesis. High gellan gum concentrations, however, did compromise cartilage matrix production and distribution, and even higher concentrations resulted in too high yield stresses to allow cell encapsulation. This study demonstrates the high potential of gelMA/gellan blends for cartilage bioprinting and identifies yield stress as dominant factor for bioprintability. PMID:27431733

  6. Yield stress determines bioprintability of hydrogels based on gelatin-methacryloyl and gellan gum for cartilage bioprinting.

    Science.gov (United States)

    Mouser, Vivian H M; Melchels, Ferry P W; Visser, Jetze; Dhert, Wouter J A; Gawlitta, Debby; Malda, Jos

    2016-07-19

    Bioprinting of chondrocyte-laden hydrogels facilitates the fabrication of constructs with controlled organization and shape e.g. for articular cartilage implants. Gelatin-methacryloyl (gelMA) supplemented with gellan gum is a promising bio-ink. However, the rheological properties governing the printing process, and the influence of gellan gum on the mechanical properties and chondrogenesis of the blend, are still unknown. Here, we investigated the suitability of gelMA/gellan for cartilage bioprinting. Multiple concentrations, ranging from 3% to 20% gelMA with 0%-1.5% gellan gum, were evaluated for their printability, defined as the ability to form filaments and to incorporate cells at 15 °C-37 °C. To support the printability assessment, yield stress and viscosity of the hydrogels were measured. Stiffness of UV-cured constructs, as well as cartilage-like tissue formation by embedded chondrocytes, were determined in vitro. A large range of gelMA/gellan concentrations were printable with inclusion of cells and formed the bioprinting window. The addition of gellan gum improved filament deposition by inducing yielding behavior, increased construct stiffness and supported chondrogenesis. High gellan gum concentrations, however, did compromise cartilage matrix production and distribution, and even higher concentrations resulted in too high yield stresses to allow cell encapsulation. This study demonstrates the high potential of gelMA/gellan blends for cartilage bioprinting and identifies yield stress as a dominant factor for bioprintability.

  7. Effect of different N fertilizer forms on antioxidant capacity and grain yield of rice growing under Cd stress

    International Nuclear Information System (INIS)

    Jalloh, Mohamed Alpha; Chen Jinghong; Zhen Fanrong; Zhang Guoping

    2009-01-01

    Cadmium contamination in soil has become a serious issue in sustainable agriculture production and food safety. A pot experiment was conducted to study the influence of four N fertilizer forms on grain yield, Cd concentration in plant tissues and oxidative stress under two Cd levels (0 and 100 mg Cd kg -1 soil). The results showed that both N form and Cd stress affected grain yield, with urea-N and NH 4 + -N treatments having significantly higher grain yields, and Cd addition reducing yield. NO 3 - -N and NH 4 + -N treated plants had the highest and lowest Cd concentration in plant tissues, respectively. Urea-N and NH 4 + -N treatments had significantly higher N accumulation in plant tissues than other two N treatments. Cd addition caused a significant increase in leaf superoxide dismutase (SOD) and peroxidase (POD) activities for all N treatments, except for NO 3 - -N treatment, with urea-N and NH 4 + -N treated plants having more increase than organic-N treated ones. The results indicated that growth inhibition, yield reduction and Cd uptake of rice plants in response to Cd addition varied with the N fertilizer form

  8. Effect of different N fertilizer forms on antioxidant capacity and grain yield of rice growing under Cd stress.

    Science.gov (United States)

    Jalloh, Mohamed Alpha; Chen, Jinghong; Zhen, Fanrong; Zhang, Guoping

    2009-03-15

    Cadmium contamination in soil has become a serious issue in sustainable agriculture production and food safety. A pot experiment was conducted to study the influence of four N fertilizer forms on grain yield, Cd concentration in plant tissues and oxidative stress under two Cd levels (0 and 100 mg Cd kg(-1)soil). The results showed that both N form and Cd stress affected grain yield, with urea-N and NH(4)(+)-N treatments having significantly higher grain yields, and Cd addition reducing yield. NO(3)(-)-N and NH(4)(+)-N treated plants had the highest and lowest Cd concentration in plant tissues, respectively. Urea-N and NH(4)(+)-N treatments had significantly higher N accumulation in plant tissues than other two N treatments. Cd addition caused a significant increase in leaf superoxide dismutase (SOD) and peroxidase (POD) activities for all N treatments, except for NO(3)(-)-N treatment, with urea-N and NH(4)(+)-N treated plants having more increase than organic-N treated ones. The results indicated that growth inhibition, yield reduction and Cd uptake of rice plants in response to Cd addition varied with the N fertilizer form.

  9. Effect of different N fertilizer forms on antioxidant capacity and grain yield of rice growing under Cd stress

    Energy Technology Data Exchange (ETDEWEB)

    Jalloh, Mohamed Alpha; Chen Jinghong; Zhen Fanrong [Department of Agronomy, Huajiachi Campus, Zhejiang University, Hangzhou 310029 (China); Zhang Guoping [Department of Agronomy, Huajiachi Campus, Zhejiang University, Hangzhou 310029 (China)], E-mail: zhanggp@zju.edu.cn

    2009-03-15

    Cadmium contamination in soil has become a serious issue in sustainable agriculture production and food safety. A pot experiment was conducted to study the influence of four N fertilizer forms on grain yield, Cd concentration in plant tissues and oxidative stress under two Cd levels (0 and 100 mg Cd kg{sup -1} soil). The results showed that both N form and Cd stress affected grain yield, with urea-N and NH{sub 4}{sup +}-N treatments having significantly higher grain yields, and Cd addition reducing yield. NO{sub 3}{sup -}-N and NH{sub 4}{sup +}-N treated plants had the highest and lowest Cd concentration in plant tissues, respectively. Urea-N and NH{sub 4}{sup +}-N treatments had significantly higher N accumulation in plant tissues than other two N treatments. Cd addition caused a significant increase in leaf superoxide dismutase (SOD) and peroxidase (POD) activities for all N treatments, except for NO{sub 3}{sup -}-N treatment, with urea-N and NH{sub 4}{sup +}-N treated plants having more increase than organic-N treated ones. The results indicated that growth inhibition, yield reduction and Cd uptake of rice plants in response to Cd addition varied with the N fertilizer form.

  10. Protective containment behaviour under exceeded design loads

    International Nuclear Information System (INIS)

    Holub, I.; Stepan, J.; Maly, J.; Schererova, K.

    2003-01-01

    The contribution describes the calculation results of the behaviour of containment structure if loaded in excess of its design load. The Temelin NPP comprises two WWER 1000 blocks and containment consists of a pre-stressed reinforced concrete structure with a system of unbonded cables. The objective of the calculations was to determine the level of load caused by the internal pressure and temperature at which the containment protective function would fail. In the first step, the maximum overpressure was determined, which may be transferred by the containment structure. In further steps analyses were made of various combinations of simultaneous pressure and temperature loads. The contribution presents relevant calculation results, including the evaluation of containment structure behaviour including liner under loads that exceed its design parameters. (author)

  11. Effects of drought stress condition on the yield of spring wheat ...

    African Journals Online (AJOL)

    use

    2011-12-14

    Dec 14, 2011 ... spikelets to booting stage affected the yield and yield components. Water deficit at this stage considerably decreased the number of spikelets per spike. The spike length reportedly showed stability under different conditions. However, the findings of Iqbal et al. (1999) on durum wheat indicated that the ...

  12. Evaluation of Foliar Spraying of Zinc and Calcium Fertilizers on Yield and Physiological Traits of Safflower under Lead Stress

    Directory of Open Access Journals (Sweden)

    P Jamshidi

    2017-10-01

    Full Text Available Introduction In order to evaluate the effect of foliar spraying of zinc and calcium on yield and physiological traits of safflower under lead stress, a factorial experiment based on randomized complete block design was performed in Kerman agricultural and natural resource research and education center in 2014-2015 with three replications. The first factorial included three levels (control, and 0.5 and 1 μM lead spraying, whereas the second and third factorials were spraying zinc sulfate at three concentrations (zero, and 10 and 20 μM and spraying calcium chloride at two levels (zero and 20 μM, respectively. According to the results, grain yield, the 1000-grain weight, leaf dry weight, number of seeds per head, head weight and chlorophyll content decreased. On the other hand, a significant increase was observed in the activities of catalase and ascorbate peroxidase enzymes and amount of malondialdehyde in plants. Moreover, spraying zinc fertilizer in lead treatment resulted in a significant increase in activity of catalase enzyme, reduction of membrane lipid peroxidation, prevention of chlorophyll destruction and maintenance of grain yield. However, the effect of spraying calcium fertilize in lead treatment was only significant on chlorophyll content. According to the results of the research, it seems that spraying zinc fertilizer had more effects on improved growth of safflower under lead stress, compared to spraying calcium fertilizer. Therefore, in air pollution with heavy metals (lead, application of zinc sulfate fertilizer can be an effective approach to maintain the growth and production of plants. Among the various heavy metals, lead (Pb is a major anthropogenic pollutant that has been released to the environment since the industrial revolution and accumulated in different terrestrial and aquatic ecosystems These elements will transfer to leaves in polluted areas and will rapidly uptake and cause irreparable damages to the most

  13. In-situ stress analysis with X-Ray diffraction for yield locus characterization of sheet metals

    Energy Technology Data Exchange (ETDEWEB)

    Güner, A.; Tekkaya, A. E. [Institute of Forming Technology and Lightweight Construction, TU Dortmund University, Baroper Str. 301, 44227 Dortmund (Germany); Zillmann, B.; Lampke, T. [Institute of Materials Science and Engineering, Chemnitz University of Technology, Erfenschlager Strasse 73 D-09125 Chemnitz (Germany)

    2013-12-16

    A main problem in the field of sheet metal characterization is the inhomogeneous plastic deformation in the gauge regions of specimens which causes the analytically calculated stresses to differ from the sought state of stress acting in the middle of the gauge region. To overcome this problem, application of X-Ray diffraction is analyzed. For that purpose a mobile X-ray diffractometer and an optical strain measurement system are mounted on a universal tensile testing machine. This enables the recording of the whole strain and stress history of a material point. The method is applied to uniaxial tension tests, plane strain tension tests and shear tests to characterize the interstitial free steel alloy DC06. The applicability of the concepts of stress factors is verified by uniaxial tension tests. The experimentally obtained values are compared with the theoretical values calculated with crystal elasticity models utilizing the orientation distribution functions (ODF). The relaxation problem is addressed which shows itself as drops in the stress values with the strain kept at a constant level. This drop is analyzed with elasto-viscoplastic material models to correct the measured stresses. Results show that the XRD is applicable to measure the stresses in sheet metals with preferred orientation. The obtained yield locus is expressed with the Yld2000–2D material model and an industry oriented workpiece is analyzed numerically. The comparison of the strain distribution on the workpiece verifies the identified material parameters.

  14. Reliability analysis for cementless hip prosthesis using a new optimized formulation of yield stress against elasticity modulus relationship

    International Nuclear Information System (INIS)

    Kharmanda, G.

    2015-01-01

    Highlights: • We develop a new formulation between the yield stress and Young’s modulus of bone. • We validate the optimized formulation for cortical and trabecular bone. • We integrate the reliability analysis into artificially hip replacement design. - Abstract: Using classical design optimization methods for implant-bone studies does not completely guarantee a safety and satisfactory performance, due in part to the randomness of bone properties and loading. Here, the material properties of the different bone layers are considered as uncertain parameters. So their corresponding yield stress values will not be deterministic, that leads to integrate variable limitations into the optimization process. Here there is a strong need to find a reliable mathematical relationship between yield stress and material properties of the different bone layers. In this work, a new optimized formulation for yield stress against elasticity modulus relationship is first developed. This model is based on some experimental results. A validation of the proposed formulation is next carried out to show its accuracy for both bone layers (cortical and cancellous). A probabilistic sensitivity analysis is then carried out to show the role of each input parameter with respect to the limit state function. The new optimized formulation is next integrated into a reliability analysis problem in order to assess the reliability level of the stem–bone study where we deal with variable boundary limitations. An illustrative application is considered as a bi-dimensional example (contains only two variables) in order to present the results in an illustrative 2D space. Finally, a multi-variable problem considering several daily loading cases on a hip prosthesis shows the applicability of the proposed strategy

  15. Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

    OpenAIRE

    M. Sarai Tabrizi; H. Babazadeh; M. Homaee; F. Kaveh Kaveh; M. Parsinejad

    2016-01-01

    Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil respon...

  16. Bingham viscosity and yield stress of molten (TeO2)0.78(WO3)0.22 glass

    International Nuclear Information System (INIS)

    Churbanov, M.F.; Snopatin, G.E.; Shaposhnikov, R.M.; Shabarov, V.V.; Plotnichenko, V.G.

    2007-01-01

    The flow of molten (TeO 2 ) 0.78 (WO 3 ) 0.22 glass in a circular-cylindrical channel has been studied at temperatures from 390 to 430 deg C. The variation of the measured volumetric flow rate with the gas pressure over the melt attests to non-Newtonian flow behavior. The flow rates calculated in the pseudo plastic model were used to determine the yield stress and plastic (Bingham) viscosity of the melt [ru

  17. Supportability of a High-Yield-Stress Slurry in a New Stereolithography-Based Ceramic Fabrication Process

    Science.gov (United States)

    He, Li; Song, Xuan

    2018-03-01

    In recent years, ceramic fabrication using stereolithography (SLA) has gained in popularity because of its high accuracy and density that can be achieved in the final part of production. One of the key challenges in ceramic SLA is that support structures are required for building overhanging features, whereas removing these support structures without damaging the components is difficult. In this research, a suspension-enclosing projection-stereolithography process is developed to overcome this challenge. This process uses a high-yield-stress ceramic slurry as the feedstock material and exploits the elastic force of the material to support overhanging features without the need for building additional support structures. Ceramic slurries with different solid loadings are studied to identify the rheological properties most suitable for supporting overhanging features. An analytical model of a double doctor-blade module is established to obtain uniform and thin recoating layers from a high-yield-stress slurry. Several test cases highlight the feasibility of using a high-yield-stress slurry to support overhanging features in SLA.

  18. Effects of arbuscular mycorrhiza inoculation on growth and yield of tomato (Lycopersicum esculentum Mill. under salinity stress

    Directory of Open Access Journals (Sweden)

    D.R.R. Damaiyanti

    2015-10-01

    Full Text Available Objective of the research was to study the effect mycorrhiza on growth and yield of tomato. The experiment was conducted in screen house 14 m x 10.5 m, in Pasuruan on November 2013 until March 2014, The experiment was conducted as a factorial randomized complete design. The first factor was dose of mycorrhiza (without mycorrhiza, 5 g mycorrhiza, 10 g mycorrhiza, and 20 g mycorrhiza. The second factor was the salinity stress level (without NaCl, 2500 ppm NaCl, 5000 ppm NaCl, and 7500 ppm NaCl. The results showed that salinity stress at the level 7500 ppm decreased the amount of fruit by 30.84% and fresh weight per hectare decreased by 51.72%. Mycorrhizal application was not able to increase the growth and yield in saline stress conditions; it was shown by the level of infection and the number of spores on the roots of tomato plants lower the salinity level 5000 ppm and 7500 ppm. But separately, application of 20 g mycorrhiza enhanced plant growth, such as plant height, leaf area, leaf number and proline. Application of 20 g mycorrhiza increased the yield by 35.99%.

  19. Seed yield and quality of pepper plants grown under salt stress ...

    African Journals Online (AJOL)

    The effect of salinity on seed yield and quality of pepper plants were evaluated. Plants were grown in five salt levels (electrical conductivity, EC): 1.0, 1.5, 2.0, 4.0 to 6.0 dSm-1 in glasshouse. Seed yield was assessed by seed weight/fruit, seed weight/plant and individual seed weight. Seed quality was measured by ...

  20. Seed yield and quality of pepper plants grown under salt stress

    African Journals Online (AJOL)

    İbrahim Demir

    2013-12-04

    Dec 4, 2013 ... The effect of salinity on seed yield and quality of pepper plants were evaluated. Plants were grown in five salt levels (electrical conductivity, EC): 1.0, 1.5, 2.0, 4.0 to 6.0 dSm-1 in glasshouse. Seed yield was assessed by seed weight/fruit, seed weight/plant and individual seed weight. Seed quality was.

  1. Evaluation of Low Pressure Fogging System for Improving Crop Yield of Tomato (Lycopersicon esculentum Mill.: Grown under Heat Stress Conditions

    Directory of Open Access Journals (Sweden)

    Kobi Shilo

    2013-06-01

    Full Text Available In Mediterranean regions, many tomato plants are grown throughout the hot summer period (May–September in sheltered cultivation, mainly for plant protection reasons. Most of the shelters that are used are low cost net houses covered with 50 mesh insect proof net. In most cases these net houses have a flat roof and no ventilation or climate control measures. This insufficient ventilation during the hot summer leads to above optimal air temperatures and causes moderate heat stress inside the shelters, which leads to yield reduction. The aim of this study was to evaluate the ability of a simple and inexpensive low pressure fogging system installed in a naturally ventilated net house to lower temperatures and improve the yield during the summer. The study showed that in areas where relative air humidity (RH during the daytime is less than 60%, tomato plants improved their performance when grown through the summer in net houses under moderate heat stress. Under fogging conditions pollen grain viability and fruit set were significantly improved. This improvement influenced the yield picked during September (104–136 DAP. However, total seasonal yield was not affected by the fogging treatment.

  2. Effect of drought stress and sulphur fertilizer on quantity and quality yield of psyllium (Plantago ovata L. in Baluchestan

    Directory of Open Access Journals (Sweden)

    M. Mousavi nik

    2016-05-01

    Full Text Available Management of chemical fertilizers application is very important issues on environment and plant yield especially in arid and-semi arid region. In order to determine the effects of drought stresses and fertilizer levels on quantity and quality yields of psyllium (Plantago ovata L., a study was conducted as split plot based on randomized complete block design with four replications at the Natural Resources and Agriculture Researches Center of Balouchestan, Iran, during growing season of 2009-2010. Treatments included different irrigation regimes (three, five and eight times irrigation during the growing season as main plots and four levels of sulphur fertilizer (0, 75, 150 and 225 kg.ha-1 sulphur as sub plot. The results showed that the irrigation regimes and sulphur fertilizer had significant effects on seed and biological yield of psyllium, so the highest seed and biological yields obtained in eight times irrigation. Also, the maximum of these factors were achieved in 225 kg.ha-1 sulphur. The highest harvest index and 1000- seed weight, No. seed per spike and No. spike per plant were observed in eight times irrigation and 225 kg.ha-1 sulphur. The highest plant height was obtained in eight times irrigation and 225 kg.ha-1 sulphur and the maximum mucilage percentage and proline content were obtained in three times irrigation. The maximum mucilage yield and carbohydrate content were achieved in eight times irrigation. Among sulphur fertilizer, the highest amounts for all factors were achieved in 225 kg.ha-1 sulphur. There was positive and significant correlation between seed yield with spike No. per plant, Seed No. per spike, 1000-Seed, biological yield and mucilage yield.

  3. Satellite-based mapping of field-scale stress indicators for crop yield forecasting: an application over Mead, NE

    Science.gov (United States)

    Yang, Y.; Anderson, M. C.; Gao, F.; Wardlow, B.; Hain, C.; Otkin, J.; Sun, L.; Dulaney, W.

    2017-12-01

    In agricultural regions, water is one of the most widely limiting factors of crop performance and production. Evapotranspiration (ET) describes crop water use through transpiration and water lost through direct soil evaporation, which makes it a good indicator of soil moisture availability and vegetation health and thus has been an integral part of many yield estimation efforts. The Evaporative Stress Index (ESI) describes temporal anomalies in a normalized evapotranspiration metric (fRET) as derived from satellite remote sensing and has demonstrated capacity to explain regional yield variability in water limited crop growing regions. However, its performance in some regions where the vegetation cycle is intensively managed appears to be degraded. In this study we generated maps of ET, fRET, and ESI at high spatiotemporal resolution (30-m pixels, daily timesteps) using a multi-sensor data fusion method, integrating information from satellite platforms with good temporal coverage and other platforms that provide field-scale spatial detail. The study was conducted over the period 2010-2014, covering a region around Mead, Nebraska that includes both rainfed and irrigated crops. Correlations between ESI and measurements of corn yield are investigated at both the field and county level to assess the value of ESI as a yield forecasting tool. To examine the role of phenology in ESI-yield correlations, annual input fRET timeseries were aligned by both calendar day and by biophysically relevant dates (e.g. days since planting or emergence). Results demonstrate that mapping of fRET and ESI at 30-m has the advantage of being able to resolve different crop types with varying phenology. The study also suggests that incorporating phenological information significantly improves yield-correlations by accounting for effects of phenology such as variable planting date and emergence date. The yield-ESI relationship in this study well captures the inter-annual variability of yields

  4. Quantitative trait loci for yield and morphological traits in maize under drought stress

    Directory of Open Access Journals (Sweden)

    Nikolić Ana

    2011-01-01

    Full Text Available Drought is one of the most important factors contributing to crop yield loss. In order to develop maize varieties with drought tolerance, it is necessary to explore the genetic basis. Mapping quantitative trait loci (QTL that control the yield and associate agronomic traits is one way of understanding drought genetics. QTLs associated with grain yield (GY, leaf width (LW3, LW4 plant height (PH, ear height (EH, leaf number (NL, tassel branch number (TBN and tassel length (TL were studied with composite interval mapping. A total of 43 QTLs were detected, distributed on all chromosomes, except chromosome 9. Phenotypic variability determined for the identified QTLs for all the traits was in the range from 20.99 to 87.24%. Mapping analysis identified genomic regions associated with two traits in a manner that was consistent with phenotypic correlation among traits, supporting either pleiotropy or tight linkage among QTLs.

  5. Yield estimation based on calculated comparisons to particle velocity data recorded at low stress

    International Nuclear Information System (INIS)

    Rambo, J.

    1993-01-01

    This paper deals with the problem of optimizing the yield estimation process if some of the material properties are known from geophysical measurements and others are inferred from in-situ dynamic measurements. The material models and 2-D simulations of the event are combined to determine the yield. Other methods of yield determination from peak particle velocity data have mostly been based on comparisons of nearby events in similar media at NTS. These methods are largely empirical and are subject to additional error when a new event has different properties than the population being used for a basis of comparison. The effect of material variations can be examined using LLNL's KDYNA computer code. The data from an NTS event provide the instructive example for simulation

  6. [Impacts of drought stress on the growth and development and grain yield of spring maize in Northeast China].

    Science.gov (United States)

    Ji, Rui-Peng; Che, Yu-Sheng; Zhu, Yong-Ning; Liang, Tao; Feng, Rui; Yu, Wen-Ying; Zhang, Yu-Shu

    2012-11-01

    Taking spring maize variety Danyu-39 as test object, an experiment was conducted in a large-scale agricultural water controlling experimental field to study the impacts of drought stress at three key growth stages, i. e. , 3-leaf-jointing, jointing-silking, and silking-milk ripe, on the growth and development and grain yield of spring maize in Northeast China. Two treatments were installed, including moderate drought stress (MS) and re-watering to suitable water (CK). Compared with CK, the MS at 3-leaf-jointing stage postponed the whole growth period of Danyu-39 by 13 d, and the plant height and leaf area at jointing stage were decreased by 29.8% and 41.2%, respectively. After re-watering, the plant height and grain yield recovered obviously, and the differences in ear characteristics and final yield were insignificant. The MS at jointing-silking stage shortened the whole growth period by 7 d, the plant height and leaf area at silking stage were decreased by 18.6% and 14.1%, respectively, the ear length, grain number per ear, ear dry mass, and grain mass per ear decreased by 6.9%, 19.1%, 28.1%, and 29.4%, respectively, and the blank stem rate increased by 13.3%. When the maize suffered from moderate drought stress at silking-milk ripe stage, the whole growth period was shortened by 15 d, the plant height and leaf area at milk ripe stage were decreased by 2.3% and 37.3%, respectively, the ear length, grain number per ear, ear dry mass, and grain mass per ear decreased by 9.2%, 24.1%, 30.8%, and 27.9%, respectively, and the blank stem rate increased by 24.5%. After re-watering at the latter two stages, the recovery of plant height was little, and the grain yield decreased significantly.

  7. Increasing Crop Yields in Water Stressed Countries by Combining Operations of Freshwater Reservoir and Wastewater Reclamation Plant

    Science.gov (United States)

    Bhushan, R.; Ng, T. L.

    2015-12-01

    Freshwater resources around the world are increasing in scarcity due to population growth, industrialization and climate change. This is a serious concern for water stressed countries, including those in Asia and North Africa where future food production is expected to be negatively affected by this. To address this problem, we investigate the potential of combining freshwater reservoir and wastewater reclamation operations. Reservoir water is the cheaper source of irrigation, but is often limited and climate sensitive. Treated wastewater is a more reliable alternative for irrigation, but often requires extensive further treatment which can be expensive. We propose combining the operations of a reservoir and a wastewater reclamation plant (WWRP) to augment the supply from the reservoir with reclaimed water for increasing crop yields in water stressed regions. The joint system of reservoir and WWRP is modeled as a multi-objective optimization problem with the double objective of maximizing the crop yield and minimizing total cost, subject to constraints on reservoir storage, spill and release, and capacity of the WWRP. We use the crop growth model Aquacrop, supported by The Food and Agriculture Organization of the United Nations (FAO), to model crop growth in response to water use. Aquacrop considers the effects of water deficit on crop growth stages, and from there estimates crop yield. We generate results comparing total crop yield under irrigation with water from just the reservoir (which is limited and often interrupted), and yield with water from the joint system (which has the potential of higher supply and greater reliability). We will present results for locations in India and Africa to evaluate the potential of the joint operations for improving food security in those areas for different budgets.

  8. A Remote-Sensing Driven Tool for Estimating Crop Stress and Yields

    Directory of Open Access Journals (Sweden)

    Martha C. Anderson

    2013-07-01

    Full Text Available Biophysical crop simulation models are normally forced with precipitation data recorded with either gauges or ground-based radar. However, ground-based recording networks are not available at spatial and temporal scales needed to drive the models at many critical places on earth. An alternative would be to employ satellite-based observations of either precipitation or soil moisture. Satellite observations of precipitation are currently not considered capable of forcing the models with sufficient accuracy for crop yield predictions. However, deduction of soil moisture from space-based platforms is in a more advanced state than are precipitation estimates so that these data may be capable of forcing the models with better accuracy. In this study, a mature two-source energy balance model, the Atmosphere Land Exchange Inverse (ALEXI model, was used to deduce root zone soil moisture for an area of North Alabama, USA. The soil moisture estimates were used in turn to force the state-of-the-art Decision Support System for Agrotechnology Transfer (DSSAT crop simulation model. The study area consisted of a mixture of rainfed and irrigated cornfields. The results indicate that the model forced with the ALEXI moisture estimates produced yield simulations that compared favorably with observed yields and with the rainfed model. The data appear to indicate that the ALEXI model did detect the soil moisture signal from the mixed rainfed/irrigation corn fields and this signal was of sufficient strength to produce adequate simulations of recorded yields over a 10 year period.

  9. Genetic Gains in Yield and Yield Related Traits under Drought Stress and Favorable Environments in a Maize Population Improved Using Marker Assisted Recurrent Selection

    Directory of Open Access Journals (Sweden)

    Folusho Bankole

    2017-05-01

    Full Text Available The objective of marker assisted recurrent selection (MARS is to increase the frequency of favorable marker alleles in a population before inbred line extraction. This approach was used to improve drought tolerance and grain yield (GY in a biparental cross of two elite drought tolerant lines. The testcrosses of randomly selected 50 S1 lines from each of the three selection cycles (C0, C1, C2 of the MARS population, parental testcrosses and the cross between the two parents (F1 were evaluated under drought stress (DS and well watered (WW well as under rainfed conditions to determine genetic gains in GY and other agronomic traits. Also, the S1 lines derived from each selection types were genotyped with single nucleotide polymorphism (SNP markers. Testcrosses derived from C2 produced significantly higher grain field under DS than those derived from C0 with a relative genetic gain of 7% per cycle. Also, the testcrosses of S1 lines from C2 showed an average genetic gain of 1% per cycle under WW condition and 3% per cycle under rainfed condition. Molecular analysis revealed that the frequency of favorable marker alleles increased from 0.510 at C0 to 0.515 at C2, while the effective number of alleles (Ne per locus decreased from C0 (1.93 to C2 (1.87. Our results underscore the effectiveness of MARS for improvement of GY under DS condition.

  10. The Effects of Drought Stress and Humic Acid on Morphological Traits, Yield and Anthocyanin of Roselle (Hibiscus sabdariffa L.

    Directory of Open Access Journals (Sweden)

    mojgan sanjarimijani

    2017-08-01

    Full Text Available Introduction Roselle (Hibiscus sabdariffa L. as a medicinal plant belongs to the Malvacea family. Their active ingredient increases under water stress. Humic acid bacteria derived from humus and other natural resources have hormonal effects and can improve nutrient absorption to enhance performance especially under stress conditions . Materials and methods This experiment was conducted in the research of agricultural education centre Jiroft in 2013. Field experiment was carried out as split plot design with three replications. Water deficit stress set as main factor with three levels (A1= Irrigation after 50, A2= 100 and A3= 150 mm evaporation from pan class A and humic acid was in four manners (B1= non humic acid, B2= once with Irrigation, B3= once with Irrigation + Once spraying, B4= once with Irrigation + twice Spraying. Humic acid was used to form Irrigation spray in order to arrange with compactness (10 kg.ha-1, (250 ml/100L. In late September, which coincides with the end of the heading, plant height, inflorescence length, number of branches, stem diameter, fresh and dry weight of plant, fresh and dry weight of sepals, were examined. Wagner method was used to measure anthocyanin content sepals (Wagner, 1979. Finally, data was analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at 5% level of probability. Results and discussion The analysis of variance showed that drought stress and humic acid had significant effect on growth parameters, vegetative and generative yield and anthocyanin. Drought stress decreased plant height, inflorescence length, stem diameterand fresh and dry weight sepals. The highest values of these traits was obtained in the first level of stress (50 mm evaporation from pan class A. Due to the reduction in mentioned properties, reducing the pressure tolerance and the subsequent reduction in drought conditions was considered as division and cell enlargement. The reduction in growth parameters

  11. Spinach biomass yield and physiological response to interactive salinity and water stress

    Science.gov (United States)

    Critical shortages of fresh water throughout arid regions means that growers must face the choice of applying insufficient fresh water, applying saline water, or consider the option of combined water and salt stress. The best approach to manage drought and salinity is evaluation of the impact of wat...

  12. Effect of heat stress at anthesis on yield formation in winter wheat

    Czech Academy of Sciences Publication Activity Database

    Hlaváčová, Marcela; Klem, Karel; Smutná, P.; Škarpa, P.; Hlavinka, Petr; Novotná, Kateřina; Rapantová, Barbora; Trnka, Miroslav

    2017-01-01

    Roč. 63, č. 3 (2017), s. 139-144 ISSN 1214-1178 Institutional support: RVO:67179843 Keywords : high temperature stress * grain s number per spike * spike productivity * phytotron * Triticum aestivum L. Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.225, year: 2016

  13. Drought stress impact on vegetable crop yields in the Elbe River lowland between 1961 and 2014

    Czech Academy of Sciences Publication Activity Database

    Potopová, V.; Štěpánek, Petr; Farda, Aleš; Türkott, L.; Zahradníček, Pavel; Soukup, J.

    2016-01-01

    Roč. 42, č. 1 (2016), s. 127-143 ISSN 0211-6820 R&D Projects: GA MŠk(CZ) LD14043; GA ČR GA13-19831S Institutional support: RVO:67179843 Keywords : standardized precipitation evapotranspiration index * drought stress * reference evapotranspiration * crop evapotranspiration * crop coefficient * Czech Republic Subject RIV: EH - Ecology, Behaviour

  14. Coupled ADCPs can yield complete Reynolds stress tensor profiles in geophysical surface flows

    NARCIS (Netherlands)

    Vermeulen, B.; Hoitink, A.J.F.; Sassi, M.G.

    2011-01-01

    We introduce a new technique to measure profiles of each term in the Reynolds stress tensor using coupled acoustic Doppler current profilers (ADCPs). The technique is based on the variance method which is extended to the case with eight acoustic beams. Methods to analyze turbulence from a single

  15. The effect of water deficit stress and nitrogen fertilizer levels on morphology traits, yield and leaf area index in maize

    International Nuclear Information System (INIS)

    Moosavi, S.G.

    2012-01-01

    In order to study the effect of water deficit stress at different growth stages and N fertilizer levels on morphological traits, yield and yield components of maize cv. Single Cross 704, an experiment was conducted as a split-plot based on a Randomized Complete Block Design with three replications. The main plot included irrigation at four levels (irrigation stop at 10-leaf, tasselling and grain-filling stages and optimum irrigation) and the sub-plot was N fertilizer at three levels (75, 150 and 225 kg N/ha). The results of analysis of variance showed that water-deficit stress and N fertilizer level significantly affected leaf area index at silking stage, ear length, grain number per ear, 1000-grain weight and grain yield. Stem diameter, ear diameter and harvest index were only affected by irrigation treatments and the interaction between irrigation and N level did not significantly affect the studied traits. Means comparison indicated that ear diameter under optimum irrigation was higher than that under the treatments of irrigation stop at 8-leaf, tasselling and grain-filling stages by 29.9, 19.1 and 33.5%, respectively; and ear length was higher than them by 38.1, 28.9 and 25.2%, respectively. Moreover, the highest grain number per ear, 1000-grain weight and grain yield were obtained under optimum irrigation treatment, and irrigation stop at 10-leaf, tasselling and grain-filling stages decreased grain yield by 52.8, 66.4 and 44.9%, respectively; and it decreased grain number/ear by 45.9, 59.3 and 30.1%, respectively. In addition, optimum irrigation treatment with mean 1000-grain weight of 289.2 g was significantly superior over other irrigation stop treatments by 27.6-42.8% and produced the highest leaf area index at silking stage (4.1). Means comparison of traits at different N levels indicated that N level of 225 kg/ha produced the highest ear length (17.82 cm), grain number per ear (401.9), 1000-grain weight (258.8 g), leaf area index at silking stage (4

  16. Impacts of Ridge-Furrow Planting on Salt Stress and Cotton Yield under Drip Irrigation

    Directory of Open Access Journals (Sweden)

    Chitao Sun

    2017-01-01

    Full Text Available Flat (F, mini-ditch (MD, and ridge-furrow (RF are three conventional cotton planting patterns that are usually adopted around the world, yet soil and crop responses to these three patterns are poorly studied, as is their suitability for increasing yield for coastal areas in Eastern China. The effects of three planting methods on water and salt dynamics as well as on growth and lint yield of cotton (Gossypium hirsutum L. were investigated in a saline field in Bohai Rim, China, to select the best planting pattern for cultivating coastal saline fields of Eastern China. Soil moisture in the root zone with RF was 11.9% and 12.1% higher than with F and MD, whereas the electrical conductivity of a saturated soil extract (ECe in the root zone with RF was 18.0% and 13.8% lower than with MD and F, respectively, during the growth period, which indicated that RF could efficiently collect rainfall and leach salt in the root zone. After drip irrigation, the infiltration and salt-leaching depth with RF were both deeper than that with F and MD. The stand establishment of MD was the highest (80.3% due to the greenhouse effect from film mulching, and was 12.8% and 4.6% higher than that with F and RF, respectively. Growth indicators and lint yield demonstrated that RF was superior to F and MD because of the higher soil moisture and lower ECe. The lint yield was significantly higher in RF, suggesting that RF can be an optimal planting pattern for agricultural reclamation in similar saline-alkaline areas around the world.

  17. Effect of Coarse Particle Volume Fraction on the Yield Stress of Muddy Sediments from Marennes Oléron Bay

    Directory of Open Access Journals (Sweden)

    A. Pantet

    2010-01-01

    Full Text Available Coastal erosion results from a combination of various factors, both natural and humaninduced, which have different time and space patterns. In addition, uncertainties still remain about the interactions of the forcing agents, as well as on the significance of non-local causes of erosion. We focused about the surface sediments in the Marennes Oléron bay, after a general description of the site that has many various activities. The superficial sediments show a mechanical behavior, mainly depends on the fine fraction for a composition that contains up to 60% of sandy material. Fine sediments fraction has a typical yield stress depending naturally of concentration or water content. This yield could be modified slightly or significantly by adding silt or sand. As a result, the rheological measurement sensitivity allows us to characterize five typical sediments that correlate with solid fraction and fine fraction.

  18. Photosynthesis and yield reductions from wheat stem sawfly (Hymenoptera: Cephidae): interactions with wheat solidness, water stress, and phosphorus deficiency.

    Science.gov (United States)

    Delaney, Kevin J; Weaver, David K; Peterson, Robert K D

    2010-04-01

    The impact of herbivory on plants is variable and influenced by several factors. The current study examined causes of variation in the impact of larval stem mining by the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), on spring wheat, Triticum aestivum L. We performed greenhouse experiments over 2 yr to (1) study whether biotic (hollow versus solid stemmed host wheat) and abiotic (water, phosphorus stress) factors interact with C. cinctus stem mining to influence degree of mined stem physiological (photosynthesis) and yield (grain weight) reductions; and (2) determine whether whole plant yield compensatory responses occur to offset stem-mining reductions. Flag leaf photosynthetic reduction was not detected 16-20 d after infestation, but were detected at 40-42 d and doubled from water or phosphorus stresses. Main stem grain weight decreased from 10 to 25% from stem mining, largely due to reductions in grain size, with greater reductions under low phosphorus and/or water levels. Phosphorus-deficient plants without water stress were most susceptible to C. cinctus, more than doubling the grain weight reduction due to larval feeding relative to other water and phosphorus treatments. Two solid stemmed varieties with stem mining had less grain weight loss than a hollow stemmed variety, so greater internal mechanical resistance may reduce larval stem mining and plant yield reductions. Our results emphasize the importance of sufficient water and macronutrients for plants grown in regions impacted by C. cinctus. Also, solid stemmed varieties not only reduce wheat lodging from C. cinctus, they may reduce harvested grain losses from infested stems.

  19. Effect of Water Stress and Sulfur Fertilizer on Grain Yield, Chlorophyll and Nutrient Status of Black Cumin (Nigella Sativa L.)

    OpenAIRE

    M. Heidari; A. R. Rezapor

    2011-01-01

    In order to study the effects of water stress and different amounts of sulfur fertilizer on grain yield, nutrient status and chlorophyll content in black cumin (Nigella sativa L.) a field experiment as split plot design with three replications was conducted at Ghaen city in 2009. Treatments included three levels of irrigation after 50, 100 and 150 mm evaporation from Class A pan as main plot and four levels of sulfur fertilizer including 0, 75, 150 and 225 kg/ha from bentonite-sulfur source a...

  20. Exogenous Cytokinins Increase Grain Yield of Winter Wheat Cultivars by Improving Stay-Green Characteristics under Heat Stress.

    Directory of Open Access Journals (Sweden)

    Dongqing Yang

    Full Text Available Stay-green, a key trait of wheat, can not only increase the yield of wheat but also its resistance to heat stress during active photosynthesis. Cytokinins are the most potent general coordinator between the stay-green trait and senescence. The objectives of the present study were to identify and assess the effects of cytokinins on the photosynthetic organ and heat resistance in wheat. Two winter wheat cultivars, Wennong 6 (a stay-green cultivar and Jimai 20 (a control cultivar, were subjected to heat stress treatment from 1 to 5 days after anthesis (DAA. The two cultivars were sprayed daily with 10 mg L-1 of 6-benzylaminopurine (6-BA between 1 and 3 DAA under ambient and elevated temperature conditions. We found that the heat stress significantly decreased the number of kernels per spike and the grain yield (P < 0.05. Heat stress also decreased the zeatin riboside (ZR content, but increased the gibberellin (GA3, indole-3-acetic acid (IAA, and abscisic acid (ABA contents at 3 to 15 DAA. Application of 6-BA significantly (P < 0.05 increased the grain-filling rate, endosperm cell division rate, endosperm cell number, and 1,000-grain weight under heated condition. 6-BA application increased ZR and IAA contents at 3 to 28 DAA, but decreased GA3 and ABA contents. The contents of ZR, ABA, and IAA in kernels were positively and significantly correlated with the grain-filling rate (P < 0.05, whereas GA3 was counter-productive at 3 to 15 DAA. These results suggest that the decrease in grain yield under heat stress was due to a lower ZR content and a higher GA3 content compared to that at elevated temperature during the early development of the kernels, which resulted in less kernel number and lower grain-filling rate. The results also provide essential information for further utilization of the cytokinin substances in the cultivation of heat-resistant wheat.

  1. Stress relaxation and activation volume at the yield point of cold worked and neutron irradiated copper single crystals

    International Nuclear Information System (INIS)

    Brunner, D.; Diehl, J.

    1979-01-01

    The effective activation volume of slip is studied after neutron irradiation in as-grown crystals as well as in predeformed ones by means of stress relaxation tests between 20 K and 200 K. The activation volume corresponding to the initial strain rate is found to be always higher in predeformed crystals than in as-grown ones. During stress relaxation the flow stress tau decreases linearly with ln(-dtau/dt) (indicating a constant activation volume) only in rare cases. Depending on predeformation and temperature several types of deviations from straight lines are observed: monotoneously bent curves, strong scattering of data points not fitting smooth curves or systematic deviations from straight lines at the beginning of relaxation. Accordingly the effective activation volumes and their dependences on stress seem to behave in a strange manner. By the aid of a previously proposed model for the deformation within the yield point elongation the results can be interpreted qualitatively by taking into account the inhomogeneity of slip and work hardening, allowing a more reliable judgement on the real activation volumes, on which a better understanding of the superposition of the two hardening mechanisms involved here can be based. (author)

  2. Metabolic stress and inflammatory response in high-yielding, periparturient dairy cows.

    Science.gov (United States)

    Trevisi, E; Amadori, M; Cogrossi, S; Razzuoli, E; Bertoni, G

    2012-10-01

    Increased disease rates are commonly reported among high-yielding dairy cows in the transition period, extending from 3 weeks before to 3 weeks after calving, and characterized by the occurrence of an inflammatory response in terms of both positive and negative acute phase proteins (APP+ and APP-). To determine the above inflammatory response, the authors had developed the Liver Functionality Index (LFI), which defines the above condition on the basis of some APP- responses (albumin, cholesterol sensu stricto+bilirubin) during the first month of lactation. In this respect, low LFI values are associated to a high inflammatory response and vice versa. The relationship between LFI and inflammatory cytokine response was investigated from day -28 to day +28 with respect to calving in 12 periparturient dairy cows showing the six highest and six lowest LFI values within a cohort of 54 high-yielding dairy cows. The hypothesis being tested was that LFI and APP- on the whole could be used as readout of successful vs. non-successful adaptation to the transition period, with a strong association to disease occurrence. In fact, low LFI cows experienced many more disease cases (13 vs. 3 in high LFI Group) and related drug treatments till day +28. Interleukin-6 (IL-6) serum concentrations were always higher in low LFI cows (Pcows at risk in the transition period toward an improved farm management. Also, our study indicates that disease cases in periparturient, high-yielding dairy cows are correlated with signs of accentuated IL-6 response and other markers of inflammatory phenomena. These likely start in the late lactation period or around dry-off, as suggested by our prepartal data, and proceed at much greater levels after calving. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Imbalance of heterologous protein folding and disulfide bond formation rates yields runaway oxidative stress

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    Tyo Keith EJ

    2012-03-01

    Full Text Available Abstract Background The protein secretory pathway must process a wide assortment of native proteins for eukaryotic cells to function. As well, recombinant protein secretion is used extensively to produce many biologics and industrial enzymes. Therefore, secretory pathway dysfunction can be highly detrimental to the cell and can drastically inhibit product titers in biochemical production. Because the secretory pathway is a highly-integrated, multi-organelle system, dysfunction can happen at many levels and dissecting the root cause can be challenging. In this study, we apply a systems biology approach to analyze secretory pathway dysfunctions resulting from heterologous production of a small protein (insulin precursor or a larger protein (α-amylase. Results HAC1-dependent and independent dysfunctions and cellular responses were apparent across multiple datasets. In particular, processes involving (a degradation of protein/recycling amino acids, (b overall transcription/translation repression, and (c oxidative stress were broadly associated with secretory stress. Conclusions Apparent runaway oxidative stress due to radical production observed here and elsewhere can be explained by a futile cycle of disulfide formation and breaking that consumes reduced glutathione and produces reactive oxygen species. The futile cycle is dominating when protein folding rates are low relative to disulfide bond formation rates. While not strictly conclusive with the present data, this insight does provide a molecular interpretation to an, until now, largely empirical understanding of optimizing heterologous protein secretion. This molecular insight has direct implications on engineering a broad range of recombinant proteins for secretion and provides potential hypotheses for the root causes of several secretory-associated diseases.

  4. Yield stress in metallic glasses: The jamming-unjamming transition studied through Monte Carlo simulations based on the activation-relaxation technique

    International Nuclear Information System (INIS)

    Rodney, David; Schuh, Christopher A.

    2009-01-01

    A Monte Carlo approach allowing for stress control is employed to study the yield stress of a two-dimensional metallic glass in the limit of low temperatures and long (infinite) time scales. The elementary thermally activated events are determined using the activation-relaxation technique (ART). By tracking the minimum-energy state of the glass for various applied stresses, we find a well-defined jamming-unjamming transition at a yield stress about 30% lower than the steady-state flow stress obtained in conventional strain-controlled quasistatic simulations. ART is then used to determine the evolution of the distribution of thermally activated events in the glass microstructure both below and above the yield stress. We show that aging below the yield stress increases the stability of the glass, both thermodynamically (the internal potential energy decreases) and dynamically (the aged glass is surrounded by higher-energy barriers than the initial quenched configuration). In contrast, deformation above the yield stress brings the glass into a high internal potential energy state that is only marginally stable, being surrounded by a high density of low-energy barriers. The strong influence of deformation on the glass state is also evidenced by the microstructure polarization, revealed here through an asymmetry of the distribution of thermally activated inelastic strains in glasses after simple shear deformation.

  5. Effect of yield strength on stress corrosion crack propagation under PWR and BWR environments of hardened stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Castano, M.L.; Garcia, M.S.; Diego, G. de; Gomez-Briceno, D. [CIEMAT, Nuclear Fission Department, Structural Materials Program, Avda. Complutense 22, 28040 Madrid (Spain)

    2004-07-01

    stress corrosion cracking of austenitic stainless steels (SS) and to quantify the effect on the crack propagation rate, an experimental research program was performed using cold and warm worked 304, 316L and 347 SS. Stress corrosion crack growth rate tests, under BWR and PWR environments have been carried out. The results obtained have permitted to determine the yield strength effect in the crack propagation of austenitic stainless steels in PWR and BWR conditions. In addition, similarities on cold work and radiation hardening in enhancing the yield strength and the stress corrosion cracking propagation at high temperature water have been evaluated. (authors)

  6. Influence of yield stress on free convective boundary-layer flow of a non-Newtonian nanofluid past a vertical plate in a porous medium

    International Nuclear Information System (INIS)

    Hady, F. M.; Ibrahim, F. S.; Abdel-Gaied, S. M.; Eid, M. R.

    2011-01-01

    The effect of yield stress on the free convective heat transfer of dilute liquid suspensions of nanofluids flowing on a vertical plate saturated in porous medium under laminar conditions is investigated considering the nanofluid obeys the mathematical model of power-law. The model used for non-Newtonian nanofluid incorporates the effects of Brownian motion and thermophoresis. The governing boundary- layer equations are cast into dimensionless system which is solved numerically using a deferred correction technique and Newton iteration. This solution depends on yield stress parameter Ω, a power-law index n, Lewis number Le, a buoyancy-ratio number Nr, a Brownian motion number Nb, and a thermophoresis number Nt. Analyses of the results found that the reduced Nusselt and Sherwood numbers are decreasing functions of the higher yield stress parameter for each dimensionless numbers, n and Le, except the reduced Sherwood number is an increasing function of higher Nb for different values of yield stress parameter

  7. Effect of magnetic field and silver nanoparticles on yield and water use efficiency of Carum copticum under water stress conditions

    Directory of Open Access Journals (Sweden)

    Seghatoleslami Mohammadjavad

    2015-03-01

    Full Text Available Normally the productivity of cropping systems in arid and semi- arid regions is very low. The sustainable agricultural systems try to find out environmental friendly technologies based on physical and biological treatments to increase crop production. In this study two irrigation treatments (control and water stress and six methods of fertilizer treatment (control, NPK-F, using magnetic band- M, using silver nano particles- N, M+N and M+N+50% F on performance of ajowan were compared. Results showed that treatments with magnetic field or base fertilizer had more yield compared to the control and silver nanoparticles (N treatments. Application of silver nanoparticles had no positive effect on yield. The highest seed and biomass WUE achieved in base fertilizer or magnetic field treatments. Under water stress treatment, seed WUE significantly increased. In conclusion magnetic field exposure, probably by encourage nutrient uptake efficiency could be applied to reduce fertilizer requirement. On the other hand the cultivation of plants under low MF could be an alternative way of WUE improving.

  8. Effect of deformation on crystallite characteristic and yield stress of zircaloy-4

    International Nuclear Information System (INIS)

    Sugondo; Futichah

    2007-01-01

    The effect of deformation (rolling) on micro strain, crystallite size, crystallite density, and yield strength of Zircaloy-4 was characterized by x-ray diffraction. The goal of this investigation is to characterize the cladding materials of PWR and the target is to have data on the crystallography of Zircaloy-4. The as-received material with the composition 1.3% Sn, 0.22% Fe, 0.1% Cr, and Zr balanced was cut 10 mm × 100 mm in size using diamond blade. The samples were cleaned and heated at 1100 °C for 2 hours and then quenched in cold water. Then the sample were cleaned and heated at 750 °C for 2 hours. Afterward the samples were cold rolled with 40%, 75%, and 80% reduction in thickness. After the preparation was completed, the crystals of the samples were characterized using X-ray diffraction. The processes being analysed were quenching followed by annealing, plastic deformation of annealing and reduction from 40% to 80%, and the constancy of the c/a ratio. From the analyses, three conclusions were obtained. Firstly, the annealing process at 750 °C of Zircaloy-4 from the quenched samples resulted in the recrystallization and the grain growth which was proven by the increase of micro strain from 25.05% to 32.83%, the increase of crystallite size from 10.1015 Å to 287.4798 Å, the decrease of dislocation density from 2.94E+16 m/m3 to 3.63E+13 m/m3, and the decrease of yield strength from 1125.52 MPa to 304.44 MPa. Secondly, the process of reduction of Zircaloy-4 from the annealed samples reduced to 80% resulted in the plastic deformation and crystallite which was shown by the decrease of micro strain from 32.83% to 3.15%, the decrease of crystallite size from 287.4798 Å to 10.9764 Å, the increase of dislocation density from 3.63E+13 m/m3 to 2.49E+16 m/m3, and the increase of yield strength from 304.44 MPa to 1057.69 MPa. Thirdly, the process of plastic deformation of Zircaloy-4 was limited by the constancy of the c/a ratio which was verified by the decrease

  9. Determination of NABE in urine of high-yield dairy cows in early lactation in conditions of moderate heat stress

    Directory of Open Access Journals (Sweden)

    Fratrić Natalija

    2010-01-01

    Full Text Available The work presents the results of investigations of the effect of moderate heat stress on the acidobasal status in high-yield dairy cows in early lactation. Improving performance in high-yield dairy cows increases their inclination toward metabolic disorders. The most likely to be affected is the acid-base balance, in particular when cows are exposed to heat stress. Investigations so far have shown that the taking of urine samples and their analysis is the best and fastest way to diagnose disorders in the acid-base balance. Investigations were carried out on 7 clinically healthy cows of the Holstein- Friesian breed in the phase of early lactation, 30 to 40 days (on days 30, 33 and 40 following calving during the summer period, during the month of July, when there were significant variations in daily and nightly temperatures. The cows were in the second and fourth lactation, the annual milk yield was 8000 L milk per cow. The average daily milk production in the early phase of lactation ranged from 35 to 40 L. The cows were fed mixed rations (TMR twice daily. Lucerne hay in limited quantities was given to the cows prior to the mixed feed ration. The ration for this animal category was optimized on the grounds of the daily milk production. The balance of cations and anions in the feed ration stood at 95 mEq/kg DM. The results clearly demonstrate the cows' response to moderate heat stress through the defense parameters in urine (urine pH, NABE (net-acid-base-excretion, acids, bases, ammonium ion (NH4. The determination of the kidney NABE yields more correct data than the urine pH on acidotic conditions. The results of examinations of the urine pH do not show any digressions from physiological values and are approximately the same in all cows during the investigated periods. Normal NABE values are from 100-200 mmol/L. Burdening with acid products results in a NABE range from 0-100mmol/L, and metabolic acidosis results in NAB<0 mmol/L. NABE in the cows

  10. Evolution of Grain Yield and its Components Relationships in Bread Wheat Genotypes under Full Irrigation and Terminal Water Stress Conditions Using Multivariate Statistical Analysis

    Directory of Open Access Journals (Sweden)

    S Mohammadi

    2014-07-01

    Full Text Available To study relationships between effective traits on wheat grain yield, the varieties Zarrin and Alvand, and some promising lines i.e. C-81-4, C-81-10, C-81-14 and C-82-12 were investigated at three sowing dates including 10 October, 1 November and 21 November. The experiment was carried out using strip plot in RCBD with three replications under two different water conditions including full-irrigation and terminal water stress at Miyandoab Agricultural Research Station in 2005-06 and 2006-07 cropping seasons. The results showed that under both full irrigation and terminal water stress conditions, grain yield had positive and significant correlation with days to heading, days to maturity, plant height, number of spikes/m2 and 1000 grain weight. Stepwise regression analysis revealed that 83 percent of yield variation under non-stressed conditions could be determined by days to maturity and number of spikes/m2 (R2 = 83% whereas these traits explained 87% of yield variation under stress conditions (R2= 87%. Path analysis indicated that number of spikes/m2 and days to maturity had the greatest positive direct and indirect effect on grain yield, under both conditions. The results of factor analysis under non-stressed condition showed that three factors explained 77% of total variation; these factors were called grain yield components, grain characteristics and plant phonology. Under non-stressed condition two factors (that were called grain yield and phenology, and plant morphology explained 88% of total variation. Cluster analysis through ward method, classified days to maturity and number of spikes/m2 in the same cluster where the grain yield was put under both conditions. It was concluded that under different sowing dates, selection based on days to maturity and number spikes/m2 could indirectly led to higher yield under both normal and water stress conditions.

  11. The Effect of Water Deficit stress on Osmotic Metabolites and Anti Oxidant System and Grain and Oil Yield of Amaranth CV. Koniz

    Directory of Open Access Journals (Sweden)

    Mehrdad Yarnia

    2015-01-01

    Full Text Available Drought is one of the most important environmental stresses that highly affect crop growth and yield. But the response of crops to stress depending on the timing of crop growth stages is different. The purpose of this study was to investigate effect of different levels of water stress (irrigation after 50, 80, 110, 140 and 170 mm evaporation from pan on different stages of Amaranth growth (establishment, branching, flowering and grain filling. To find the effects of water deficit stress on this plant it was decided to determine its protein percentage, oil and grain yields under drought stress. Evaluation of physiological characteristics as to the extent of osmotic adjustment and antioxidant activity was also carried out. Results showed that water deficit stress,depending on the severity and duration of stress, caused a reduction between between a minimum of 10 to a maximum of 89 percent in yield, 28 to 70 percent in harvest index, 12 to 32 percent in grain protein and 29 to 97 percent in oil yield. This indicates the high sensitivity of grain and oil yields to severe and prolonged drought stresses. Changes in osmotic substances (proline and soluble carbohydrates showed that this crop under water stress conditions increased proline and soluble carbohydrates by 31 and 50 percents, respectively. Thus, if could be said that under severe droughts the ability of crops to cops with drought will be reduced. Similarly, amaranth, to cope with water stress, increases the amount of antioxidant enzymes like catalase, peroxidase and super oxid dismutase up to 53, 23 and 79%, respectively. Higher amount of super oxid dismutase enzyme produce as the result of drought stress may play an important role to cope with reactive oxygen species and oxidative stresses.

  12. Abscisic acid, a stress hormone helps in improving water relations and yield of sunflower (helianthus annuus l.) hybrids under drought

    International Nuclear Information System (INIS)

    Hussain, S.; Saleem, M.F.; Cheema, M.A.; Ashraf, M.Y.; Haq, M.A.

    2010-01-01

    Genotypic variation in water relations under drought is an important index of studying drought tolerance of crops. Abscisic acid (ABA) application helped in mitigating drought stress by improving water relations and yield. Three sunflower hybrids viz., DK-4040 (tall stature), S-278 (medium stature) and SF-187 (short stature) were subjected to different irrigation and ABA application regimes i.e., four irrigations (25 days after sowing (DAS), at bud initiation, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with ABA spray at bud initiation, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with ABA spray at flower initiation. The experiment was laid out in randomized complete block design with split plot arrangement and had three replications. Exogenous application of ABA under drought at either stage (bud or flower initiation) was helpful in ameliorating drought stress by improving water relations and yield of sunflower hybrids; however response was better when ABA was applied under drought at bud initiation than at flower initiation stage. Sunflower hybrid DK- 4040 showed better enhancement of drought tolerance by exogenous application of ABA under drought than SF-187 and S-278 because it showed more improvement in water potential, osmotic potential, turgor pressure, relative leaf water contents and achene yield. (author)

  13. Effect of Salicylic Acid on Yield, Component Yield and Essential Oil of Black Cumin (Nigella sativa L. under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    E. Rezaei Chiyaneh

    2014-12-01

    Full Text Available Since the production of medicinal plants can be influenced by environmental factors such as water limitation. In other hand salicylic acid as a plant regulator can enhance drought resistance in plants. In order to investigate the effect of different irrigation intervals on yield, yield components and essential oil of black cumin (Nigella sativa L., a field experiment was conducted a farm located in West Azerbaijan province- city Nagadeh, West- Azerbaijan, during growing season of 2011- 2012. The experiment was arranged as split plot based on a randomized complete block design with three replications. Irrigation intervals (6, 12 and 18 days and three levels of salicylic acid concentration (0, 0.5 and 1 mM considered as in main plots and sub-plots, respectively. Results showed that irrigation had significant effects on all characteristics such as Plant height, number of follicule per plant, number of seed per follicule, biological yield, grain yield, essential oil content and essential oil yield with the exception of 1000- seed weight. With increasing irrigation intervals from 6 to 18 days, plant height, number of follicule per plant, number of seed per follicule, biological yield, grain yield, essential oil percentage and essential oil yield were decreased up to 49, 52, 40, 35, 43, 20 and 55 %, respectively. In contrast, yield components and yield were enhanced up to treatments 0.5 mM of salicylic acid. Grain yield and essential oil yield with application of 0.5 mM salicylic acid increased up to 13 and 11 % compared to control, respectively. It seems that due to the limited sources of water in the region irrigation after 12 days and 0.5 mM salicylic acid concentration are suitable for black cumin grain production.

  14. Cowpea (Vigna unguiculata L. Walp. Metabolomics: Osmoprotection as a Physiological Strategy for Drought Stress Resistance and Improved Yield

    Directory of Open Access Journals (Sweden)

    Piebiep Goufo

    2017-04-01

    Full Text Available Plants usually tolerate drought by producing organic solutes, which can either act as compatible osmolytes for maintaining turgor, or radical scavengers for protecting cellular functions. However, these two properties of organic solutes are often indistinguishable during stress progression. This study looked at individualizing properties of osmotic adjustment vs. osmoprotection in plants, using cowpea as the model species. Two cultivars were grown in well-watered soil, drought conditions, or drought followed by rewatering through fruit formation. Osmoadaptation was investigated in leaves and roots using photosynthetic traits, water homoeostasis, inorganic ions, and primary and secondary metabolites. Multifactorial analyses indicated allocation of high quantities of amino acids, sugars, and proanthocyanidins into roots, presumably linked to their role in growth and initial stress perception. Physiological and metabolic changes developed in parallel and drought/recovery responses showed a progressive acclimation of the cowpea plant to stress. Of the 88 metabolites studied, proline, galactinol, and a quercetin derivative responded the most to drought as highlighted by multivariate analyses, and their correlations with yield indicated beneficial effects. These metabolites accumulated differently in roots, but similarly in leaves, suggesting a more conservative strategy to cope with drought in the aerial parts. Changes in these compounds roughly reflected energy investment in protective mechanisms, although the ability of plants to adjust osmotically through inorganic ions uptake could not be discounted.

  15. Cowpea (Vigna unguiculata L. Walp.) Metabolomics: Osmoprotection as a Physiological Strategy for Drought Stress Resistance and Improved Yield.

    Science.gov (United States)

    Goufo, Piebiep; Moutinho-Pereira, José M; Jorge, Tiago F; Correia, Carlos M; Oliveira, Manuela R; Rosa, Eduardo A S; António, Carla; Trindade, Henrique

    2017-01-01

    Plants usually tolerate drought by producing organic solutes, which can either act as compatible osmolytes for maintaining turgor, or radical scavengers for protecting cellular functions. However, these two properties of organic solutes are often indistinguishable during stress progression. This study looked at individualizing properties of osmotic adjustment vs. osmoprotection in plants, using cowpea as the model species. Two cultivars were grown in well-watered soil, drought conditions, or drought followed by rewatering through fruit formation. Osmoadaptation was investigated in leaves and roots using photosynthetic traits, water homoeostasis, inorganic ions, and primary and secondary metabolites. Multifactorial analyses indicated allocation of high quantities of amino acids, sugars, and proanthocyanidins into roots, presumably linked to their role in growth and initial stress perception. Physiological and metabolic changes developed in parallel and drought/recovery responses showed a progressive acclimation of the cowpea plant to stress. Of the 88 metabolites studied, proline, galactinol, and a quercetin derivative responded the most to drought as highlighted by multivariate analyses, and their correlations with yield indicated beneficial effects. These metabolites accumulated differently in roots, but similarly in leaves, suggesting a more conservative strategy to cope with drought in the aerial parts. Changes in these compounds roughly reflected energy investment in protective mechanisms, although the ability of plants to adjust osmotically through inorganic ions uptake could not be discounted.

  16. Dry matter yield and nitrogen-15 uptake by tomatoes under sodium chloride stress

    International Nuclear Information System (INIS)

    Pessarakli, M.; Tucker, T.C.

    1988-01-01

    An absorption study was conducted in nutrient solution with seedlings of tomato (Lycopersicon esculentum Mill; cv. Columbia) to observe the effects of NaCl on ( 15 N) uptake and distribution in plant roots and shoots. The 14-d-old seedlings were grown for 16 d in complete Hoagland solution no. 1, then salinized (except the controls, -0.03 MPa) to -0.3, -0.6, and -0.9 MPa osmotic potentials with NaCl. Nutrient solutions were sampled daily for N loss after addition of 15 NH 4 15 NO 3 to the pots. The cumulative 15 N loss was considered to be absorbed by plants. Lowering the osmotic potential of the culture solution decreased total N uptake at all salinity levels, and 15 N uptake of the plants at medium and high salinity levels. A low level of salinity did not affect 15 N uptake compared with the control. Water uptake and dry matter yield were affected to a greater extent than 15 N absorption. Nitrogen-15 concentration was slightly higher in roots than in shoots

  17. Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad Waraich

    2017-05-01

    Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

  18. Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

    Directory of Open Access Journals (Sweden)

    M. Sarai Tabrizi

    2016-10-01

    Full Text Available Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil response to salinity and to evaluate the effectiveness of available mathematical models for the yield estimation of the Basil . Materials and Methods: The extensive experiments were conducted with 13 natural saline water treatments including 1.2, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 5, 6, 8, and 10 dSm-1. Water salinity treatments were prepared by mixing Shoor River water with fresh water. In order to quantify the salinity effect on Basil yield, seven mathematical models including Maas and Hoffman (1977, van Genuchten and Hoffman (1984, Dirksen and Augustijn (1988, and Homaee et al., (2002 were used. One of the relatively recent methods for soil water content measurements is theta probes instrument. Theta probes instrument consists of four probes with 60 mm long and 3 mm diameter, a water proof container (probe structure, and a cable that links input and output signals to the data logger display. The advantages that have been attributed to this method are high precision and direct and rapid measurements in the field and greenhouse. The range of measurements is not limited like tensiometer and is from saturation to wilting point. In this study, Theta probes instrument was calibrated by weighing method for exact irrigation scheduling. Relative transpiration was calculated using daily soil water content changes. A coarse sand layer with 2 centimeters thick was used to decrease evaporation from the surface soil of the pots. Quantity comparison of the used models was done

  19. Salt Stress Responses of Pigeon Pea (Cajanus Cajan) on Growth, Yield and Some Biochemical Attributes

    International Nuclear Information System (INIS)

    Tayyab, A.; Azeem, M.; Ahmad, N; Ahmad, R.; Qasim, M.

    2016-01-01

    Growth responses of leguminous plants to salinity vary considerably among species. Pigeon pea (Cajanus cajan (L.) Millsp.) is a sub-tropical crop, grown worldwide particularly in South Asia for edible and fodder purposes, while little is known about its salinity tolerance. In order to investigate the effect of salinity, plants were established at six different levels of sea salt concentrations i.e. 0.5, 1.6, 2.8, 3.5, 3.8 and 4.3 (EC/sub e/ dS.m/sup -1/). Plant growth was measured using vegetative (height, fresh and dry biomass, moisture, relative growth rate (RGR) and specific shoot length (SSL)), reproductive (number of flowers, pods, seeds and seed weight) and some biochemical parameters (chlorophylls, carotenoids, sugars and proteins). Pigeon pea showed a salt sensitive growth response, however, it survived up to 3.5 (EC/sub e/ dS.m/sup -1/) sea salt salinity. Plant height, biomass, SSL and RGR linearly decreased under saline conditions. Leaf pigments increased (chlorophylls) or maintained (carotenoids) at 1.6 dS.m/sup -1/ and subsequently decreased in higher salinity. Low moisture content and succulence along with more accumulation of soluble sugars and proteins may be attributed to leaf osmotic adjustments at low salinity. Salinity adversely affect reproductive growth of C. cajan where production of flowers, pods, number of seeds and seed weight were significantly reduced. Present study provides basic information related to plant growth, seed yield and some biochemical attributes, which suggest C. cajan as a salt sensitive leguminous crop. However, detailed information is required to understand the eco-physiological responses of this plant under field and green house conditions. (author)

  20. Maximizing Lipid Yield in Neochloris oleoabundans Algae Extraction by Stressing and Using Multiple Extraction Stages with N-Ethylbutylamine as Switchable Solvent

    Science.gov (United States)

    2017-01-01

    The extraction yield of lipids from nonbroken Neochloris oleoabundans was maximized by using multiple extraction stages and using stressed algae. Experimental parameters that affect the extraction were investigated. The study showed that with wet algae (at least) 18 h extraction time was required for maximum yield at room temperature and a solvent/feed ratio of 1:1 (w/w). For fresh water (FW), nonstressed, nonbroken Neochloris oleoabundans, 13.1 wt % of lipid extraction yield (based on dry algae mass) was achieved, which could be improved to 61.3 wt % for FW stressed algae after four extractions, illustrating that a combination of stressing the algae and applying the solvent N-ethylbutylamine in multiple stages of extraction results in almost 5 times higher yield and is very promising for further development of energy-efficient lipid extraction technology targeting nonbroken wet microalgae. PMID:28781427

  1. Hardening of particle/oil/water suspensions due to capillary bridges: Experimental yield stress and theoretical interpretation.

    Science.gov (United States)

    Danov, Krassimir D; Georgiev, Mihail T; Kralchevsky, Peter A; Radulova, Gergana M; Gurkov, Theodor D; Stoyanov, Simeon D; Pelan, Eddie G

    2018-01-01

    Suspensions of colloid particles possess the remarkable property to solidify upon the addition of minimal amount of a second liquid that preferentially wets the particles. The hardening is due to the formation of capillary bridges (pendular rings), which connect the particles. Here, we review works on the mechanical properties of such suspensions and related works on the capillary-bridge force, and present new rheological data for the weakly studied concentration range 30-55 vol% particles. The mechanical strength of the solidified capillary suspensions, characterized by the yield stress Y, is measured at the elastic limit for various volume fractions of the particles and the preferentially wetting liquid. A quantitative theoretical model is developed, which relates Y with the maximum of the capillary-bridge force, projected on the shear plane. A semi-empirical expression for the mean number of capillary bridges per particle is proposed. The model agrees very well with the experimental data and gives a quantitative description of the yield stress, which increases with the rise of interfacial tension and with the volume fractions of particles and capillary bridges, but decreases with the rise of particle radius and contact angle. The quantitative description of capillary force is based on the exact theory and numerical calculation of the capillary bridge profile at various bridge volumes and contact angles. An analytical formula for Y is also derived. The comparison of the theoretical and experimental strain at the elastic limit reveals that the fluidization of the capillary suspension takes place only in a deformation zone of thickness up to several hundred particle diameters, which is adjacent to the rheometer's mobile plate. The reported experimental results refer to water-continuous suspension with hydrophobic particles and oily capillary bridges. The comparison of data for bridges from soybean oil and hexadecane surprisingly indicate that the yield strength is

  2. Random regression models to account for the effect of genotype by environment interaction due to heat stress on the milk yield of Holstein cows under tropical conditions.

    Science.gov (United States)

    Santana, Mário L; Bignardi, Annaiza Braga; Pereira, Rodrigo Junqueira; Menéndez-Buxadera, Alberto; El Faro, Lenira

    2016-02-01

    The present study had the following objectives: to compare random regression models (RRM) considering the time-dependent (days in milk, DIM) and/or temperature × humidity-dependent (THI) covariate for genetic evaluation; to identify the effect of genotype by environment interaction (G×E) due to heat stress on milk yield; and to quantify the loss of milk yield due to heat stress across lactation of cows under tropical conditions. A total of 937,771 test-day records from 3603 first lactations of Brazilian Holstein cows obtained between 2007 and 2013 were analyzed. An important reduction in milk yield due to heat stress was observed for THI values above 66 (-0.23 kg/day/THI). Three phases of milk yield loss were identified during lactation, the most damaging one at the end of lactation (-0.27 kg/day/THI). Using the most complex RRM, the additive genetic variance could be altered simultaneously as a function of both DIM and THI values. This model could be recommended for the genetic evaluation taking into account the effect of G×E. The response to selection in the comfort zone (THI ≤ 66) is expected to be higher than that obtained in the heat stress zone (THI > 66) of the animals. The genetic correlations between milk yield in the comfort and heat stress zones were less than unity at opposite extremes of the environmental gradient. Thus, the best animals for milk yield in the comfort zone are not necessarily the best in the zone of heat stress and, therefore, G×E due to heat stress should not be neglected in the genetic evaluation.

  3. Interactive effects of high temperature and drought stress during stem elongation, anthesis and early grain filling on the yield formation and photosynthesis of winter wheat

    Czech Academy of Sciences Publication Activity Database

    Hlaváčová, Marcela; Klem, Karel; Rapantová, Barbora; Novotná, Kateřina; Urban, Otmar; Hlavinka, Petr; Smutná, P.; Horáková, V.; Škarpa, P.; Pohanková, Eva; Wimmerová, Markéta; Orság, Matěj; Jurečka, František; Trnka, Miroslav

    2018-01-01

    Roč. 221, MAY (2018), s. 182-195 ISSN 0378-4290 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LM2015061; GA MŠk(CZ) EF16_013/0001609 Institutional support: RVO:86652079 Keywords : carbon-isotope discrimination * triticum-aestivum-l. * heat-stress * climate-change * reproductive growth * leaf senescence * gas-exchange * water -stress * durum-wheat * responses * Drought stress * Heat stress * Photosynthesis * Triticum aestivum * Yield formation Subject RIV: GC - Agronomy OBOR OECD: Agronomy, plant breeding and plant protection Impact factor: 3.048, year: 2016

  4. Improving adaptation to drought stress in white pea bean (Phaseolus vulgaris L): genotypic effects on grain yield, yield components and pod harvest index

    Science.gov (United States)

    Common bean (Phaseolus vulgaris L.) is the most important food legume crop in Africa and Latin America where rainfall pattern is unpredictable. The objectives were to identify better yielding common bean lines with good canning quality under drought, and to identify traits that could be used as sele...

  5. Effect of Drought Stress During Phenological Stage and Biofertilizer and Nitrogen Application on Yield and Yield Components of Corn (KSC 704

    Directory of Open Access Journals (Sweden)

    M. Ashkavand

    2013-06-01

    Full Text Available To study the effect of cutting irrigation and application of biofertilizer and nitrogen on yield and yield components of corn single cross hybrid, an experiment was carried out in Satloo Agricultural and Natural resources Research Station of west Azarbaijan, 2009-2010. This experiment was arranged as split plot based on Randomized Complete Block Design with three replications.Four irrigation factors including I1, I2, I3 and I4, respectively: cutting irrigations at stem elongation, blossom and seed filling stages and normal irrigation assigned to main plots and fertilizer treatments consisted of Nitoxin + 50% urea (F1 , Niragin + 50% urea (F2 , and without biofertilizer application + 100% urea (F3 were allocated to sub plots.Results indicated that the effect of cutting irrigations had negative and significant effects on all characteristics; Fertilizer treatments on the other hand had significant effect only on seed numbers per ear, 100 seeds weight and seed yield. The highest seed yield was obtained under normal irrigation and treatment of Nitragin + 50% urea (12320.7 kg/ha and 11100.5 kg/ha respectively.

  6. Effect of Silicon application on Morpho-physiological Characteristics, Grain Yield and Nutrient Content of Bread Wheat under Water Stress Conditions

    Directory of Open Access Journals (Sweden)

    A. Karmollachaab

    2015-03-01

    Full Text Available In order to investigate the effect of silicon application on some physiological characteristics, yield and yield components, and grain mineral contents of bread wheat (Triticum aestivum under water stress condition, an experiment was conducted in Ramin Agriculture and Natural Resources University, Khuzestan, in 2012. The experiment was arranged in split-plots design in RCBD (Completely Randomized Blocks Design with three replications. Treatments consisted of drought stress (irrigation after 25, 50 and 75% depletion of Available Water Content in main plots and silicon (0, 10, 20 and 30 Kg Si ha-1 arranged in sub-plots. Results showed that the effect of drought stress was significant on most traits and led to the increase of electrolyte leakage (EL, cuticular wax, leaf and grain silicon content and grain nitrogen content. But drought led to negative impacts on grain yield and its components, and leaf potassium content, i.e. moderate and severe stresses reduced yield by 17% and 38% compared to control, respectively. Effect of silicon application was significant on all traits except for spike per square meter. Silicon had the greatest impact on EL and led to 35% decrease in this trait. Also, silicon led to increase in leaf and grain silicon contents and grain K content and grain yield and yield components, when applied at 30 kg ha-1. Generally, application of 30 kg ha-1 of silicon led to 6 and 14% increases of grain yield at the presence of moderate and severe drought stresses, respectively. Thus, given the abundance of silicon it can be used as an ameliorating element for planting bread wheat in drought-prone conditions.

  7. Glucose concentration and blood acid-basis status in high-yielding dairy cows during heat stress

    Directory of Open Access Journals (Sweden)

    Vujanac Ivan

    2011-01-01

    Full Text Available The objective of this work was to examine the effect of heat stress on glucose and pH values in blood of high-yielding dairy cows in the early stage of lactation, as well as to determine whether the changes in these parameters are interdependent under such conditions. An experiment was performed on high-yielding dairy cows during the summer and the spring periods. Forty cows were selected, twenty each for the two periods under investigation. In the course of the experiment, the temperature humidity index (THI was determined for the entire period of investigations, and then also the average daily THI, nightmorning THI (average value of hourly THI measured from 22h on the previous day until 10h of the current day, as well as the day-night THI (average value of hourly THI measured during the period from 10h to 22h of the current day. The pH and glucose concentration were determined in blood samples taken in the morning and afternoon of days 30, 60, and 90 of lactation during the spring and summer periods of the investigations. Based on the results for the THI, it was established that the animals were not exposed to the effect of extreme heat stress during the spring period of investigations, while they were periodically exposed to moderate but also extreme heat stress during the summer, in particular in the afternoon hours. It can be concluded from the results obtained for the blood pH that the cows were in respiratory alkalosis during the summer in the morning and afternoon hours on day 30, in the afternoon hours of days 60 and 90 of lactation, as well as in the afternoon on day 90 of lactation during the spring period of investigations. During the summer period, there were no statistically significant differences between the pH value determined in the morning and afternoon hours on day 30 of lactation, while the pH value was significantly higher in the afternoon hours than in the morning hours on days 60 and 90 of lactation. There were no

  8. Remote detection of water stress conditions via a diurnal photochemical reflectance index (PRI) improves yield prediction in rainfed wheat

    Science.gov (United States)

    Magney, T. S.; Vierling, L. A.; Eitel, J.

    2014-12-01

    Employing remotely sensed techniques to quantify the existence and magnitude of midday photosynthetic downregulation using the photochemical reflectance index (PRI) may reveal new information about plant responses to abiotic stressors in space and time. However, the interpretation and application of the PRI can be confounded because of its sensitivity to several variables changing at the diurnal (e.g., irradiation, shadow fraction) and seasonal (e.g., leaf area, chlorophyll and carotene pigment concentrations, irradiation) time scales. We explored different techniques to correct the PRI for variations in canopy structure and relative chlorophyll content (ChlR) using highly temporally resolved (frequency = five minutes) in-situ radiometric measurements of PRI and the Normalized Difference Vegetation Index (NDVI) over eight soft white spring wheat (Triticum aestivum L.)field plots under varying nitrogen and soil water conditions over two seasons. Our results suggest that the influence of seasonal variation in canopy ChlR and LAI on the diurnally measured PRI (PRIdiurnal) can be minimized using simple correction techniques, therefore improving the strength of PRI as a tool to quantify abiotic stressors such as daily changes in soil volumetric water content (SVWC), and vapor pressure deficit (VPD). PRIdiurnal responded strongly to available nitrogen, and linearly tracked seasonal changes in SVWC, VPD, and stomatal conductance (gc). Utilizing the PRI as an indicator of stress, yield predictions significantly over greenness indices such as the NDVI. This study provides insight towards the future interpretation and scaling of PRI to quantify rapid changes in photosynthesis, and as an indicator of plant stress.

  9. Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L. Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

    Directory of Open Access Journals (Sweden)

    Kamrun NAHAR

    2010-09-01

    Full Text Available Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, Sufi, Shatabdi and Bijoy were evaluated under two growing environments; one is normal growing environment (sowing at November 30 and the other is post anthesis heat stressed environment (sowing at December 30. In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23C in case of normal seeding and it was near about 28C to 30C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was lower. Days to anthesis and booting decreased due to late sown heat stress condition regardless the cultivars. These phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower the grain yield as compared to normal condition. Due to heat stress, the yield reduction was 69.53% in Sourav, 58.41% in Pradip, 73.01% in Sufi, 55.46% in Shatabdi and 53.42% in Bijoy.

  10. The influence of zeta potential and yield stress on the filtration characteristics of a magnesium hydroxide simulant

    International Nuclear Information System (INIS)

    Biggs, Simon; Nabi, Rafiq; Poole, Colin; Patel, Ashok

    2007-01-01

    In the UK, irradiated fuels from Magnox reactors are often stored in water-filled ponds under alkaline conditions, so as to minimise corrosion of fuel cladding. This is important to prevent or reduce leakage of soluble fission products and actinides to the pond water. A variety of intermediate level wastes derived from Magnox materials are stored at power stations. Under these alkaline conditions, various species of magnesium are formed, of which magnesium hydroxide is the dominant material. The particle-fluid interactions are significant for the design and operation of facilities for hydraulic retrieval, filtration, dewatering and ion exchange treatment of fuel storage pond water and stored wet Magnox wastes. Here we describe a study of particulate properties and filtration characteristics of oxide particle simulants under laboratory conditions. Cake and medium resistance data were correlated across a range of pH conditions with electro-acoustic zeta potential and shear yield stress measurements, as a function of particle volume fractions. The influence of zeta potential on filtration properties arises directly from the interaction of particles within the sediment cake. (authors)

  11. Genetic Analysis of Yield and Physiological Traits in Sunflower (Helianthus annuus L. under Irrigation and Drought Stress

    Directory of Open Access Journals (Sweden)

    Azam POURMOHAMMAD

    2014-06-01

    Full Text Available Implementing appropriate breeding strategies for sunflower, alongside dependable information on heritability and gene effects upon yield and related traits under drought conditions, are all necessary. Thirty sunflower hybrids were produced by line × tester cross of six male-sterile and five restorer lines. Their hybrids were evaluated in three levels of irrigation, as follows: (1 non-stressed plots, irrigated at regular intervals (W1; (2 mild water stress (W2, irrigated from the beginning of the button stage (R4 to seed filling initiation (R6; (3 severe water stress (W3 started from the beginning of button stage (R4 to physiological maturity. Based on observations and specific methods for determination, canopy temperatures, chlorophyll index, relative water content and proline content, were studied by additive effects, under the different irrigation conditions. Canopy temperatures,chlorophyll index, relative water content, leaf water potential, proline content and yield were controlled by additive effects under mild stressed conditions. Under severe stress conditions however, canopy temperatures, leaf water potential and proline content were controlled by additive effects, while chlorophyll index and relative water content were controlled by both additive and dominant effects, as seed yield was mainly influenced by the dominant effects. The narrow sense heritability ranged from 47-97% for all traits, except for chlorophyll fluorescence. Yield correlated positively with chlorophyll index and relative water content, and negatively with canopy temperature and leaf water potential. Therefore, under drought stressed conditions in breeding programs, canopy temperatures, chlorophyll index and relative water content can be reliable criteria for the selection of tolerant genotypes with prospect to higher yields.

  12. Genotypic variability in faba bean (vicia faba L.) for seed yield and protein content under drought stress during vegetative and Reproductive Stages

    International Nuclear Information System (INIS)

    Abdelmula, A. A.; Gasim, S. M.; Link, W.; Mohamed, A. A.; Khalifa, J. E.

    2012-01-01

    Faba bean (viciafaba L.) is subjected to drought stress during different growth stages. In this study, variability in seed yield and protein content was investigated when drought occurred during the vegetative and reproductive stages. Twenty two genotypes of faba bean were field evaluated under three levels of drought stress at two locations in the Sudan. The three levels of drought were normal watering (non-stress), drought during the vegetative stage and drought during the reproductive stage. Data were collected on yield and vegetative traits and protein content. The results showed that yield, as well as other traits, were reduced by drought. The genotypes exhibited significant differences for 100 seed weight, plant height and protein content. The interaction between the genotypes and drought was significant for yield/plant. Some genotypes were more sensitive when drought occurred during the vegetative stage, some when drought occurred during the vegetative stage, and others were more stable under the three levels of drought. yield/plant showed significant covariance with pods/plant and plant height. The association between different characters varied according to trait and the time of drought incidence. The correlation of yield/plant with protein content was negative under all drought levels, and the average correlation coefficient was 0.32. It could be concluded that the specific adaptation and the wide adaptation have great implication for improving faba bean under drought. To select for high seed yield under drought, secondary characters, such as pods/plant and plant height could be of great importance. Drought could reduce protein content and affect its association with yield/plant.(Author)

  13. Maximizing Lipid Yield in Neochloris oleoabundans Algae Extraction by Stressing and Using Multiple Extraction Stages with N-Ethylbutylamine as Switchable Solvent

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Brilman, Derk W.F.

    2017-01-01

    (Graph Presented) The extraction yield of lipids from nonbroken Neochloris oleoabundans was maximized by using multiple extraction stages and using stressed algae. Experimental parameters that affect the extraction were investigated. The study showed that with wet algae (at least) 18 h extraction

  14. Effect of Salinity Stress and Foliar Application of Methyl Jasmonate on Photosynthetic Rate, Stomatal Conductance, Water Use Efficiency and Yield of German Chamomile

    Directory of Open Access Journals (Sweden)

    fatemeh Salimi

    2014-09-01

    Full Text Available Jasmonate is new plant growth regulator that plays an essential role at increasing plants resistance to the environmental stresses like salinity stress. Hence, in this research the effect of foliar application of methyl jasmonate on some physiological indices and yield of German chamomile under salinity conditions was studied. A factorial experiment was laid out based on randomized complete block design (RCBD with three replications in the greenhouse condition. Foliar application of methyl jasmonate was five levels (MJ1; 0, MJ2; 75, MJ3; 150, MJ4; 225 and MJ5; 300 μM and salinity stress was four levels (S1; 2, S2; 6, S3; 10, S4; 14 dS m-1. The effect of methyl jasmonate, salinity condition treatments and their interaction was significant for traits of photosynthesis rate, stomata conductance, transpiration rate, carboxylation efficiency, intercellular CO2 concentration and yield of flower. The highest values of photosynthetic rate, stomata conductance, transpiration rate, carboxylation efficiency and yield of flower (3.76 g pot-1 and the lowest intercellular CO2 concentration were achieved at MJ×S treatment. Maximum value of photosynthetic water use efficiency was revealed at MJ5×S2 treatment. With decreasing stomata conductance, photosynthetic water use efficiency and intercellular CO2 concentration were increased. In general, it seems that application of methyl jasmonate by lower dose (MJ2 under salinity conditions especially mild salinity stress (S2 can improve physiological indices and yield of chamomile.

  15. Heat waves imposed during early pod development in soybean (Glycine max) cause significant yield loss despite a rapid recovery from oxidative stress.

    Science.gov (United States)

    Siebers, Matthew H; Yendrek, Craig R; Drag, David; Locke, Anna M; Rios Acosta, Lorena; Leakey, Andrew D B; Ainsworth, Elizabeth A; Bernacchi, Carl J; Ort, Donald R

    2015-08-01

    Heat waves already have a large impact on crops and are predicted to become more intense and more frequent in the future. In this study, heat waves were imposed on soybean using infrared heating technology in a fully open-air field experiment. Five separate heat waves were applied to field-grown soybean (Glycine max) in central Illinois, three in 2010 and two in 2011. Thirty years of historical weather data from Illinois were analyzed to determine the length and intensity of a regionally realistic heat wave resulting in experimental heat wave treatments during which day and night canopy temperatures were elevated 6 °C above ambient for 3 days. Heat waves were applied during early or late reproductive stages to determine whether and when heat waves had an impact on carbon metabolism and seed yield. By the third day of each heat wave, net photosynthesis (A), specific leaf weight (SLW), and leaf total nonstructural carbohydrate concentration (TNC) were decreased, while leaf oxidative stress was increased. However, A, SLW, TNC, and measures of oxidative stress were no different than the control ca. 12 h after the heat waves ended, indicating rapid physiological recovery from the high-temperature stress. That end of season seed yield was reduced (~10%) only when heat waves were applied during early pod developmental stages indicates the yield loss had more to do with direct impacts of the heat waves on reproductive process than on photosynthesis. Soybean was unable to mitigate yield loss after heat waves given during late reproductive stages. This study shows that short high-temperature stress events that reduce photosynthesis and increase oxidative stress resulted in significant losses to soybean production in the Midwest, U.S. The study also suggests that to mitigate heat wave-induced yield loss, soybean needs improved reproductive and photosynthetic tolerance to high but increasingly common temperatures. Published 2015. This article is a U.S. Government work and is

  16. Effect of maltose and trehalose on growth, yield and some biochemical components of wheat plant under water stress

    Directory of Open Access Journals (Sweden)

    Hemmat A. Ibrahim

    2016-12-01

    Full Text Available In the greenhouse experiment, wheat plants (Triticum aestivum L. cv. Giza 168 were treated with 10 mM of maltose and trehalose as foliar spray using Tween 20 as wetting agent at 15, 30 and 45 days post sowing with two times of irrigation at 10 and 20 days intervals. Two samples were taken after 45 and 120 days from planting. At the first sample date, plant height, shoot fresh and dry weights and leaf area were recorded. At harvesting time (the second sample no. of spikes/plant, no. of spikelets/plant and weight of 1000 grains were taken. Chemical analyses were conducted in leaves at the first sample date for determination of phenolic compounds, flavonoids, amino acids, reducing sugars, total soluble sugars, protein, proline, PAL, POD, ascorbate peroxidase, catalase, PPO and MDA. The obtained results indicated that maltose and trehalose had significant and positive effect on most growth parameters. Opposite trend was found in plant height, no. of spike/plant and weight of 1000 grains by drought treatment. Maltose and trehalose treatments enhanced in the most biochemical components whereas they decreased PAL and catalase activity. Variable trends in amino acids and ascorbate peroxidase were observed by drought. However, the drought has more stimulative effect in most cases than the first time period of irrigation. The results concluded that foliar applications with maltose or trehalose induced water stress tolerance in wheat plants. Maltose treatment gave the best results in most morphological parameters, grains yield and biochemical components than trehalose treatment.

  17. Detrimental effect of selection for milk yield on genetic tolerance to heat stress in purebred Zebu cattle: Genetic parameters and trends.

    Science.gov (United States)

    Santana, M L; Pereira, R J; Bignardi, A B; Filho, A E Vercesi; Menéndez-Buxadera, A; El Faro, L

    2015-12-01

    In an attempt to determine the possible detrimental effects of continuous selection for milk yield on the genetic tolerance of Zebu cattle to heat stress, genetic parameters and trends of the response to heat stress for 86,950 test-day (TD) milk yield records from 14,670 first lactations of purebred dairy Gir cows were estimated. A random regression model with regression on days in milk (DIM) and temperature-humidity index (THI) values was applied to the data. The most detrimental effect of THI on milk yield was observed in the stage of lactation with higher milk production, DIM 61 to 120 (-0.099kg/d per THI). Although modest variations were observed for the THI scale, a reduction in additive genetic variance as well as in permanent environmental and residual variance was observed with increasing THI values. The heritability estimates showed a slight increase with increasing THI values for any DIM. The correlations between additive genetic effects across the THI scale showed that, for most of the THI values, genotype by environment interactions due to heat stress were less important for the ranking of bulls. However, for extreme THI values, this type of genotype by environment interaction may lead to an important error in selection. As a result of the selection for milk yield practiced in the dairy Gir population for 3 decades, the genetic trend of cumulative milk yield was significantly positive for production in both high (51.81kg/yr) and low THI values (78.48kg/yr). However, the difference between the breeding values of animals at high and low THI may be considered alarming (355kg in 2011). The genetic trends observed for the regression coefficients related to general production level (intercept of the reaction norm) and specific ability to respond to heat stress (slope of the reaction norm) indicate that the dairy Gir population is heading toward a higher production level at the expense of lower tolerance to heat stress. These trends reflect the genetic

  18. Effect of Organic and Chemical Fertilizers on Yield and Essential Oil of Two Ecotypes of Savory (Satureja hortensis L. under Normal and Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    O Akrami nejad

    2016-02-01

    height, grain and biological yield, chlorophyll index, ionic leakage, relative water content, number of branches, essence percentage and essence amount were evaluated. Data were analyzed with SAS and MSTAT-C software and mean comparison was done using Duncan test at %5 level. Results and Discussion The results showed that drought stress reduced plant height, number of branches, oil yield, relative water content, SPAD index and increased ion leakage. Meanwhile, it had no significant effect on the percent of oil. Fertilizers increased plant height, number of branches, yield, chlorophyll index and oil yield, while it decreased ion leakage in contrast with control. Baher et al (2002 have reported that drought stress reduced plant height, grain yield, and branches number of Savory. As nutrients deficit is one of the main factors in control of plant height and yield, plant that were treated with control had the lowest growth. Organic fertilizers provide appropriate plant growth via gradual release of nutrients during growth season and saving water. Two ecotypes had significant differences for yield, number of branches and ionic leakage. Kerman ecotype showed better yield performance. The results showed that water stress reduced yield, number of branches and plant height of savory. Meanwhile fertilizers (especially cow and hen manure could reduce the effects of drought. Conclusions Generally, organic fertilizers, especially cow manure, produced higher yield and showed a better response to drought stress. It might be for higher moisture maintenance in contrast with chemical fertilizers. It seems that, using cow manure could be helpful to overcome the negative effects of drought stress.

  19. Genetic Gains in Grain Yield of a Maize Population Improved through Marker Assisted Recurrent Selection under Stress and Non-stress Conditions in West Africa

    Directory of Open Access Journals (Sweden)

    Rekiya O. Abdulmalik

    2017-05-01

    Full Text Available Marker-assisted recurrent selection (MARS is a breeding method used to accumulate favorable alleles that for example confer tolerance to drought in inbred lines from several genomic regions within a single population. A bi-parental cross formed from two parents that combine resistance to Striga hermonthica with drought tolerance, which was improved through MARS, was used to assess changes in the frequency of favorable alleles and its impact on inbred line improvement. A total of 200 testcrosses of randomly selected S1 lines derived from the original (C0 and advanced selection cycles of this bi-parental population, were evaluated under drought stress (DS and well-watered (WW conditions at Ikenne and under artificial Striga infestation at Abuja and Mokwa in Nigeria in 2014 and 2015. Also, 60 randomly selected S1 lines each derived from the four cycles (C0, C1, C2, C3 were genotyped with 233 SNP markers using KASP assay. The results showed that the frequency of favorable alleles increased with MARS in the bi-parental population with none of the markers showing fixation. The gain in grain yield was not significant under DS condition due to the combined effect of DS and armyworm infestation in 2015. Because the parents used for developing the bi-parental cross combined tolerance to drought with resistance to Striga, improvement in grain yield under DS did not result in undesirable changes in resistance to the parasite in the bi-parental maize population improved through MARS. MARS increased the mean number of combinations of favorable alleles in S1 lines from 114 in C0 to 124 in C3. The level of heterozygosity decreased by 15%, while homozygosity increased by 13% due to the loss of some genotypes in the population. This study demonstrated the effectiveness of MARS in increasing the frequency of favorable alleles for tolerance to drought without disrupting the level of resistance to Striga in a bi-parental population targeted as a source of improved

  20. Genetic Gains in Grain Yield of a Maize Population Improved through Marker Assisted Recurrent Selection under Stress and Non-stress Conditions in West Africa.

    Science.gov (United States)

    Abdulmalik, Rekiya O; Menkir, Abebe; Meseka, Silvestro K; Unachukwu, Nnanna; Ado, Shehu G; Olarewaju, Joseph D; Aba, Daniel A; Hearne, Sarah; Crossa, Jose; Gedil, Melaku

    2017-01-01

    Marker-assisted recurrent selection (MARS) is a breeding method used to accumulate favorable alleles that for example confer tolerance to drought in inbred lines from several genomic regions within a single population. A bi-parental cross formed from two parents that combine resistance to Striga hermonthica with drought tolerance, which was improved through MARS, was used to assess changes in the frequency of favorable alleles and its impact on inbred line improvement. A total of 200 testcrosses of randomly selected S 1 lines derived from the original (C 0 ) and advanced selection cycles of this bi-parental population, were evaluated under drought stress (DS) and well-watered (WW) conditions at Ikenne and under artificial Striga infestation at Abuja and Mokwa in Nigeria in 2014 and 2015. Also, 60 randomly selected S 1 lines each derived from the four cycles (C 0 , C 1 , C 2 , C 3 ) were genotyped with 233 SNP markers using KASP assay. The results showed that the frequency of favorable alleles increased with MARS in the bi-parental population with none of the markers showing fixation. The gain in grain yield was not significant under DS condition due to the combined effect of DS and armyworm infestation in 2015. Because the parents used for developing the bi-parental cross combined tolerance to drought with resistance to Striga , improvement in grain yield under DS did not result in undesirable changes in resistance to the parasite in the bi-parental maize population improved through MARS. MARS increased the mean number of combinations of favorable alleles in S 1 lines from 114 in C 0 to 124 in C 3 . The level of heterozygosity decreased by 15%, while homozygosity increased by 13% due to the loss of some genotypes in the population. This study demonstrated the effectiveness of MARS in increasing the frequency of favorable alleles for tolerance to drought without disrupting the level of resistance to Striga in a bi-parental population targeted as a source of improved

  1. The Effect of Silicon on some Morpho-physiological Characteristics and Grain Yield of Sorghum (Sorghum bicolor L. under Salt Stress

    Directory of Open Access Journals (Sweden)

    S Hasibi

    2016-12-01

    Full Text Available Introduction Nowadays, salinity is one of the limiting factors for crop production in arid and semi-arid regions. On the other hand, sorghum (Sorghum bicolor L. is a self-pollinated and short-day plant, which partly has been adapted to salinity and water stress conditions; also play an important role in humans, livestock and poultry nourishments. All studies have showed the positive effects of Silicon on growth and yield of plants in both normal and stress conditions. The aim of this experiment was to improve salinity tolerance of Sorghum by application of Silicon. Materials and Methods A split plot experiment based on randomized complete block design with three replications in both normal and salt stress conditions was carried out at research farm of Shahid Bahonar University of Kerman in 2013. Silicon treatments (0 and 6 mM were considered as main plot and various sorghum genotypes (payam, sepideh, TN-4-70, TN-04-71, TN-04-39, TN-04-107, TN-04-100, TN-04-37, TN-04-68, TN-04-83, TN-04-62 and TN-04-95 were assigned to sub plots. The sodium silicate was used as silica source. The data were analyzed by SAS software using combine analysis. Means comparisons were accomplished by Duncan multiple range test at 5% probability level. Some of the measured traits were as follow: Relative water content (Ritchie and Nguyen, 1990, Relative permeability (33, leaf area index and chlorophyll index (by SPAD. Results and Discussion According to the results, use of silicon led to increase of RWC under salinity stress, while RWC decreased by 13% when no silicon applied. Salinity significantly decreased 1000-grain weight. Maximum grain yield obtained from TN-04-37 (987.6 g m-2 under normal condition with foliar application of silicon. Application of silicon under stress condition led to 38% increase in grain yield of Sepideh compared to control. Under salt stress, silicon also increased shoot dry weight in TN-04-107, TN-04-70, TN-04-37, Payam and Sepideh genotypes

  2. Improvement of antioxidant activities and yield of spring maize through seed priming and foliar application of plant growth regulators under heat stress conditions

    Directory of Open Access Journals (Sweden)

    Ijaz Ahmad

    2017-03-01

    Full Text Available Heat stress during reproductive and grain filling phases adversely affects the growth of cereals through reduction in grain’s number and size. However, exogenous application of antioxidants, plant growth regulators and osmoprotectants may be helpful to minimize these heat induced yield losses in cereals. This two year study was conducted to evaluate the role of exogenous application of ascorbic acid (AsA, salicylic acid (SA and hydrogen peroxide (H2O2 applied through seed priming or foliar spray on biochemical, physiological, morphological and yield related traits, grain yield and quality of late spring sown hybrid maize. The experiment was conducted in the spring season of 2007 and 2008. We observed that application of AsA, SA and H2O2 applied through seed priming or foliar spray improved the physiological, biochemical, morphological and yield related traits, grain yield and grain quality of late spring sown maize in both years. In both years, we observed higher superoxide dismutase (SOD, catalase (CAT and peroxidase (POD activity in the plants where AsA, SA and H2O2were applied through seed priming or foliar spray than control. Membrane stability index (MSI, relative water contents (RWC, chlorophyll contents, grain yield and grain oil contents were also improved by exogenous application of AsA, SA and H2O2 in both years. Seed priming of AsA, SA and H2O2was equally effective as the foliar application. In conclusion, seed priming with AsA, SA and H2O2 may be opted to lessen the heat induced yield losses in late sown spring hybrid maize. Heat tolerance induced by ASA, SA and H2O2 may be attributed to increase in antioxidant activities and MSI which maintained RWC and chlorophyll contents in maize resulting in better grain yield in heat stress conditions.

  3. Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L. Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

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    Kamrun NAHAR

    2010-09-01

    Full Text Available Phenological performance in relation to yield of five modern varieties of wheat �Sourav�, �Pradip�, �Sufi�, �Shatabdi� and �Bijoy� were evaluated under two growing environments; one is normal growing environment (sowing at November 30 and the other is post anthesis heat stressed environment (sowing at December 30. In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23�C in case of normal seeding and it was near about 28�C to 30�C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was lower. Days to anthesis and booting decreased due to late sown heat stress condition regardless the cultivars. These phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower the grain yield as compared to normal condition. Due to heat stress, the yield reduction was 69.53% in �Sourav�, 58.41% in �Pradip�, 73.01% in �Sufi�, 55.46% in �Shatabdi� and 53.42% in �Bijoy�.

  4. Sequential path analysis for determining interrelationships between yield and related traits in tobacco (Nicotiana tabacum L. under normal and abiotic stress conditions

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    Bayat Mahdi

    2014-01-01

    Full Text Available In the present work the relationships between yield and its related traits were investigated in tobacco genotypes under normal and abiotic stress conditions (Orobanche aegyptiaca weed at Urmia Tobacco Research Centre, Iran, during 2006-2009 cropping seasons. The experimental design was a randomized complete block design (RCBD with three replications in each condition every year. Analysis of variance revealed extent genetic variability among the genotypes for most of the traits studied. In comparison with normal condition, the mean value of studied traits decreased in stress condition. LAI and FD showed the maximum and minimum diminution in the mean values under stress condition compared to normal one so known as more sensitive and more tolerant traits, respectively. Based on CV values, the traits FD and DLYP showed the minimum and maximum variation among traits in both normal and stress conditions. Correlation analysis revealed significant and positive correlations between DLYP with all studied traits in both normal and stress conditions. Path analysis detected the traits including biomass, APDW and DWR as the first-order variables at normal condition and biomass, APDW, DWR and harvest index as the first-order variables under abiotic stress condition. Based on results, the traits such as biomass, APDW, DWR detected as more important factors in both conditions can be used in tobacco breeding programs for increasing yield. Abbreviation: aerial part fresh weight without leaves weight (APFW, aerial part dry weight without leaves weight (APDW, biomass (BIO, coefficient of variation (CV, dry weight of root (DWR, flowering date (FD, fresh weight of leaf (FWL, fresh weight of root (FWR, harvest index (HI, leaf area index (LAI, dry leaf yield per plant (DLYP, number of leaf (NL, plant height (PH, randomized complete block design (RCBD, standard deviation (Std.

  5. Effect of water stress on total biomass, tuber yield, harvest index and water use efficiency in Jerusalem artichoke

    Science.gov (United States)

    The objectives of this study were to determine the effect of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought str...

  6. Assesment of economic benefits of foliarly applied osmoprotectants in alleviating the adverse effects of water stress on growth and yield of cotton (gossypium hirsutum L.)

    International Nuclear Information System (INIS)

    Zafar, Z. U.; Hussain, K.; Athar, H. U. R.

    2015-01-01

    Water stress reduces crop growth and productivity by affecting various physiological and biochemical processes. Although foliar application of osmoprotectants alleviates the detrimental effects of drought stress growth and productivity of crops, its economic benefits on large scale has not been explored yet. The studies were carried out to quantify the interactive effects of some osmoprotectantsand various watering regimes on cotton crop. The treatments consisted of water stress and osmoprotectant applications ((a) two watering regimes (well watered, 2689m /sup 3/ water; drought stressed, 2078m /sup 3/), and (b) three osmoprotectants (untreated check; water spray containing 0.1 percentage Tween-80; salicylic acid (100 mg L /sup -1/); proline (100 mg L /sup -1/); glycine betaine (100 mg L /sup -1/)) in split plot design. The crop was subjected to drought stress at day 45 after sowing, i.e. at the flowering stage. The solutions of osmoprotectants were foliarly applied after two weeks of imposition of water stress (at the peak flowering stage). The results showed that imposition of water stress caused substantial reduction in plant growth, biological yield, fruit production, and fiber characteristics as compared to fully irrigated cotton crop. However, the application of osmoprotectants was found effective in off-setting the negative impacts of drought stress. The exogenous application of salicylic acid (100 mgL /sup -1/) caused improvement by 47.9 percentage, 36.5 percentage, 17.4 percentage, 4.86 percentage and 9.9 percentage in main stem height, biological yield, fruit production, fiber length and seed cotton yield over an untreated check, respectively. The efficiency of various osmoprotectants was in order of salicylic acid > glycinebetaine > proline in alleviating the harmful effects of drought stress. The usage of osmoprotectants was also found most cost-effective and the value for money. The cost-benefit ratio was 1:9.1, 1:3.9 and 1:1.7 by spraying of salicylic

  7. Evaluation of anisotropic effective stress-strain criteria for the biaxial yield and flow of 2024 aluminum tubes

    International Nuclear Information System (INIS)

    Stout, M.G.; Hecker, S.S.; Bourcier, R.

    1983-01-01

    2024 aluminum tubes, heat treated to a T6 and T8 temper, were tested in combinations of tension-internal pressure and tension-torsion loading. Yield loci and flow behavior were determined for both modes of loading and compared to theoretical predictions. Both tempers of 2024 aluminum exhibited crystallographic textures and anisotropic yield and flow. Hill's quadratic yield criterion and the associated flow rule under-estimate balanced biaxial yield and flow, which is consistent with hydraulic bulge data on other face-centered cubic metals. Hill's nonquadratic criterion, which adds one additional parameter, and Bassani's criterion, which adds two parameters, predict the anisotropic yield behavior much more accurately. Predictions of the complete flow behavior, including strain paths, with these anisotropic criteria could be improved markedly by including provisions for planar anisotropy

  8. The Effect of Silicon on some Morpho-physiological Characteristics and Grain Yield of Sorghum (Sorghum bicolor L.) under Salt Stress

    OpenAIRE

    S Hasibi; H Farahbakhsh; Gh Khajoeinejad

    2016-01-01

    Introduction Nowadays, salinity is one of the limiting factors for crop production in arid and semi-arid regions. On the other hand, sorghum (Sorghum bicolor L.) is a self-pollinated and short-day plant, which partly has been adapted to salinity and water stress conditions; also play an important role in humans, livestock and poultry nourishments. All studies have showed the positive effects of Silicon on growth and yield of plants in both normal and stress conditions. The aim of this exp...

  9. Water stress drastically reduces root growth and inulin yield in Cichorium intybus (var. sativum) independently of photosynthesis

    Science.gov (United States)

    Vandoorne, B.; Mathieu, A.-S.; Van den Ende, W.; Vergauwen, R.; Périlleux, C.; Javaux, M.; Lutts, S.

    2012-01-01

    Root chicory (Cichorium intybus var. sativum) is a cash crop cultivated for inulin production in Western Europe. This plant can be exposed to severe water stress during the last 3 months of its 6-month growing period. The aim of this study was to quantify the effect of a progressive decline in water availability on plant growth, photosynthesis, and sugar metabolism and to determine its impact on inulin production. Water stress drastically decreased fresh and dry root weight, leaf number, total leaf area, and stomatal conductance. Stressed plants, however, increased their water-use efficiency and leaf soluble sugar concentration, decreased the shoot-to-root ratio and lowered their osmotic potential. Despite a decrease in photosynthetic pigments, the photosynthesis light phase remained unaffected under water stress. Water stress increased sucrose phosphate synthase activity in the leaves but not in the roots. Water stress inhibited sucrose:sucrose 1-fructosyltransferase and fructan:fructan 1 fructosyltransferase after 19 weeks of culture and slightly increased fructan 1-exohydrolase activity. The root inulin concentration, expressed on a dry-weight basis, and the mean degree of polymerization of the inulin chain remained unaffected by water stress. Root chicory displayed resistance to water stress, but that resistance was obtained at the expense of growth, which in turn led to a significant decrease in inulin production. PMID:22577185

  10. A Comparative Study Between Strain And Stress Based Forming Limit Analysis By Applying Several Phenomenological Yield Criteria

    International Nuclear Information System (INIS)

    Butuc, Marilena C.; Vincze, Gabriela T.; Gracio, Jose J.; Barata da Rocha, A.

    2005-01-01

    The present work aims at analyzing a comparative study between the strain-based forming limit criterion (FLD) and the stress-based forming limit criterion (FLSD), under linear and complex strain paths. The selected material is an AA5182-0 aluminium alloy. Some relevant remarks about stress-based forming limit criterion concept are presented

  11. Natural convection in Bingham plastic fluids from an isothermal spheroid: Effects of fluid yield stress, viscous dissipation and temperature-dependent viscosity

    Science.gov (United States)

    Gupta, Anoop Kumar; Gupta, Sanjay; Chhabra, Rajendra Prasad

    2017-08-01

    In this work, the buoyancy-induced convection from an isothermal spheroid is studied in a Bingham plastic fluid. Extensive results on the morphology of approximate yield surfaces, temperature profiles, and the local and average Nusselt numbers are reported to elucidate the effects of the pertinent dimensionless parameters: Rayleigh number, 102 ≤ Ra ≤ 106; Prandtl number, 20 ≤ Pr ≤ 100; Bingham number, 0 ≤ Bn ≤ 103, and aspect ratio, 0.2 ≤ e ≤ 5. Due to the fluid yield stress, fluid-like (yielded) and solid-like (unyielded) regions coexist in the flow domain depending upon the prevailing stress levels vis-a-vis the value of the fluid yield stress. The yielded parts progressively grow in size with the rising Rayleigh number while this tendency is countered by the increasing Bingham and Prandtl numbers. Due to these two competing effects, a limiting value of the Bingham number ( Bn max) is observed beyond which heat transfer occurs solely by conduction due to the solid-like behaviour of the fluid everywhere in the domain. Such limiting values bear a positive dependence on the Rayleigh number ( Ra) and aspect ratio ( e). In addition to this, oblate shapes ( e 1) impede it. Finally, simple predictive expressions for the maximum Bingham number and the average Nusselt number are developed which can be used to predict a priori the overall heat transfer coefficient in a new application. Also, a criterion is developed in terms of the composite parameter Bn• Gr-1/2 which predicts the onset of convection in such fluids. Similarly, another criterion is developed which delineates the conditions for the onset of settling due to buoyancy effects. The paper is concluded by presenting limited results to delineate the effects of viscous dissipation and the temperature-dependent viscosity on the Nusselt number. Both these effects are seen to be rather small in Bingham plastic fluids.

  12. A Modified Eyring Equation for Modeling Yield and Flow Stresses of Metals at Strain Rates Ranging from 10−5 to 5 × 104 s−1

    Directory of Open Access Journals (Sweden)

    Ramzi Othman

    2015-01-01

    Full Text Available In several industrial applications, metallic structures are facing impact loads. Therefore, there is an important need for developing constitutive equations which take into account the strain rate sensitivity of their mechanical properties. The Johnson-Cook equation was widely used to model the strain rate sensitivity of metals. However, it implies that the yield and flow stresses are linearly increasing in terms of the logarithm of strain rate. This is only true up to a threshold strain rate. In this work, a three-constant constitutive equation, assuming an apparent activation volume which decreases as the strain rate increases, is applied here for some metals. It is shown that this equation fits well the experimental yield and flow stresses for a very wide range of strain rates, including quasi-static, high, and very high strain rates (from 10−5 to 5 × 104 s−1. This is the first time that a constitutive equation is showed to be able to fit the yield stress over a so large strain rate range while using only three material constants.

  13. MAXIMIZING PROFIT - OPTICAL TRADITIONAL TRAVEL AGENCIES EXCEEDED

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    ENEA CONSTANŢA

    2013-12-01

    Full Text Available Recently concepts of globalized the services the advertising only that and substantial modifications, but that just radicals, in the structure net of touristic states. Is directed to of a new conceive the organic fashions of structures ale net of realized and of casting of guy colaborative, baze on interconexion, the interface and flexible interactions, from which his. I result the competitive advantages popularly the partners of business. The optics traditional agencies of tourings considered the production and the delivery touristic services except through the of a alone objective major prism scilicet maximizarea of the profits, falls to is exceeded. For the past decades ale the century XX, the impact technological changes in the industry services becomes all determine maul influenced the „traditional sectors” in charge, as for example the education, the trade, the touring, the informatics. Certainly, globalized can be interpretation in different senses. Referenced to the touristic services, the globalized is define as be a form an advanced still more complex maul of which nationalization involves a degrees of functional integration between the touristic activities disperse on plans transfrontalier.

  14. Effect of Three Species of Mycorrhiza Inoculation on Yield and Some Physiological properties of Two Potato Cultivars under Drought Stress in Controlled Conditions

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    S. Khaninejad

    2017-03-01

    , soil and mycorrhizal active parts (spore and hyphae provided by corn root during a four-month period, in root space. Results and Discussion The results indicated that Agria cultivar in higher than Fontana. The drought stress decreased bush height, totally fungi resulted in increasing bush height in both cultivars. However, leaf area of Fontana was more than Agria; drought stress decreased leaf area but using Glomus fasciculatum and Glomus mosseae fungi increased the plant height in both cultivars. Among the treatments, the effect of cultivar on chlorophyll fluorescence was significant and there was no significant difference with each other. Only the effect of cultivar on chlorophyll fluorescence was significant among the treatments and there was no significant difference among other treatments. The amount of Spad index in Agria was 10% more than Fontana. This parameter was observed much more in control treatment than fungal treatments; drought stress indicated higher spad. There was a significant difference between Agria and Fontana cultivars for tuber weight. Fontana increased the production to 36% by producing 129g tuber to Agria cultivar. This difference was observed in control treatment and drought stress. Among various cultivars, Glomus fasciculatum and Glomus mosseae were significantly different from other treatments with 120 and 123gr tuber, respectively; and control treatment contained the least one with a 75g tuber. The interaction of fungus and stress indicated that there was no significant difference in Fontana cultivar and in mycorrhizal treatments for single-bush yield; but in control treatment, this rate was the least and had significant difference with other treatments. The most significant difference among stress levels was observed in Glomus intraradices; in this fungus, control treatment indicated 44% yield more than drought stress. Fontana indicated a significant difference to Agria cultivar for four tubers in a bush, averagely. Control treatment

  15. The Effect of Drought Stress on Grain Yield and Oil Rate and Protein Percentage of Four Varieties Castor in Climatic Conditions of Damghan

    Directory of Open Access Journals (Sweden)

    Gh. Laei

    2012-08-01

    Full Text Available In this study theeffect ofdrought stress was investigated on grain yield and oil rate and protein percentage of four varieties of castor in the climatic conditions of Damghan. The experiment was done in the research farm of Damghan Islamic Azad University(Iranin 2011 assplit plots in a randomized complete block design with three replications. The main plots of drought stress were 5, 10 and15 days and another factor included four varities of castor ( one-flower, two- flower, local and red-flower which were performed in stable density of fivebushes per cultured square meter. Therefore, after gremination, the amount of irrigation water was recorded using volumetric meters. The traits evaluated included oil rate,seed protein percentage, andgrainyield. The results show that two-flower variety with 1241 kg per hectare on 5-day drought stress has the most grain yield. Most oil rate was observed in two-flower variety on 5 day drought stress with 496.4 kg/ha.

  16. Comparative effectiveness of Pseudomonas and Serratia sp. containing ACC-deaminase for improving growth and yield of wheat (Triticum aestivum L.) under salt-stressed conditions.

    Science.gov (United States)

    Zahir, Zahir Ahmad; Ghani, Usman; Naveed, Muhammad; Nadeem, Sajid Mahmood; Asghar, Hafiz Naeem

    2009-05-01

    Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under axenic conditions at 1, 5, 10 and 15 dS m(-1). Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m(-1). Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m(-1). Similarly, chlorophyll content and K(+)/Na(+) of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene. The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction.

  17. Impact of mild heat stress on dry matter intake, milk yield and milk composition in mid-lactation Holstein dairy cows in a temperate climate.

    Science.gov (United States)

    Gorniak, Tobias; Meyer, Ulrich; Südekum, Karl-Heinz; Dänicke, Sven

    2014-01-01

    The aim of the present study was to evaluate the impact of summer temperatures in a temperate climate on mid-lactation Holstein dairy cows. Therefore, a data set was examined comprising five trials with dairy cows conducted at the experimental station of the Friedrich-Loeffler-Institute in Braunschweig, Germany. The temperature-humidity index (THI) was calculated using temperature and humidity data from the barns recorded between January 2010 and July 2012. By using a generalised additive mixed model, the impact of increasing THI on dry matter intake, milk yield and milk composition was evaluated. Dry matter intake and milk yield decreased when THI rose above 60, whilst water intake increased in a linear manner beyond THI 30. Furthermore, milk protein and milk fat content decreased continuously with increasing THI. The present results revealed that heat stress exists in Lower Saxony, Germany. However, further research is necessary to describe the mode of action of heat stress. Especially, mild heat stress has to be investigated in more detail and appropriate heat stress thresholds for temperate climates have to be developed.

  18. Effect of Water Stress and Spraying of Potassium Iodide on Agronomic Traits and Grain Yield of Bread Wheat (Tiriticum aistivum L. Genotypes

    Directory of Open Access Journals (Sweden)

    N. Pooladsaz

    2011-01-01

    Full Text Available Abstract In order to study the effect of water stress and chemical desiccation (potassium iodide on grain yield and agronomic traits of 8 wheat genotypes, a field experiment was conducted using a split split plot design based on a randomized complete block design with three replications in Torogh Agricultural and Natural Resources Research Station (Mashhad, Iran in 2006-2007 and 2007-2008. Main plots were assigned to two levels of water stress treatments; D1: optimum irrigation, and D2: cessation of watering from anthesis to maturity stages. Sub plots were assigned to eight bread wheat genotypes: 9103, 9116, 9203, 9205, 9207, 9212, C-81-10 and Cross Shahi (drought sensitive; and photosynthetic conditions with two levels: P1: using of current photosynthesis and P2: inhibition of current photosynthesis were in sub-sub plots. The results showed that the effects of water stress and photosynthetic conditions on number of total florets per spike (NTF/S, seed set percentage (SSP, spike harvest index (SHI, duration of grain filling (DGF and grain yield (GY were significant. There was a significant difference between genotypes for spike dry weight at anthesis (SDWA, number of spikletes per spike (NSP/S, NTF/S, SSP, SHI, spike partitioning coefficient (SPC, plant height (PLH, spike length (SL, DGF and GY. 9103 genotype produced the most GY (7870 kg/ha under D1P1 treatment. The least GY ( 1114 kg/ha related to Cross Shahi cultivar under D2P2 treatment. Considering that C-81-10, 9103 and 9116 genotypes showed the highest grain yield, potential for reserves and remobilizations of assimilates under different irrigation conditions thus, these genotypes could be introduced as promising in breeding programs for arid and semi-arid regions. Keywords: Triticum aestivum L., Cessation of watering, Chemical Desiccation, Spike, Grain yield

  19. Acceptable-doses exceeding in radionuclides transport

    International Nuclear Information System (INIS)

    Delabarre, P.

    2006-01-01

    Without any foregoing signal, the 12-gliding month dose in an employee of a radionuclides transporting firm raised to 44,30 mSv (over the double of the ICRP recommended yearly maximum of 20 mSv). Apart from immediate prohibition of any further professional exposure to ionising radiation for the employee concerned, and an inquiry for possible explanations concerning as well the employer as the employee, an in-depth investigation of the employees previous records took place. Except from the sudden rise, the investigation showed that the personal dosimeter was mostly presented for analysis weeks, even months, too late, what made any immediate action from occupational health and radioprotection side difficult and anyhow far too late. Investigation of the records of the other 30 employees showed that 1) mostly the dosimeters were not presented on the assumed date for analysis, but months to (sometimes) nearly one year late behind schedule 2) for the same job in the same period, registered doses varied from naught to over 8,00 mSv, depending on the employee 3) several employees had a 12-gliding months dose of over 10,00 mSv, even over 15,00 mSv During discussion with employee, employer, occupational physician and an agent of the qualified organisation for dosimeter analysis, the employer was anything but cooperative; the employee also was rather reluctant to answer questions, and given possible causes could not be corroborated. In an attempt to clarify the multiple problems, the Governmental Agency for Nuclear Control was involved, which imposed in a first time a( not very stringent, rather indulgent) action plan. Meanwhile, a written comment on the monthly dosimeter analyses was sent from as well the occupational physician as the analytical firm to the employer and to the concerned employees if a 12-gliding months dose exceeding 10 mSv was determined, without any reaction neither from the employer nor the employees. At the moment of the abstract submission (sept 05

  20. The Effect of Water Stress and Polymer on Water Use Efficiency, Yield and several Morphological Traits of Sunflower under Greenhouse Condition

    Directory of Open Access Journals (Sweden)

    Hossein NAZARLI

    2010-12-01

    Full Text Available In many part of Iran, the reproductive growth stages of sunflower (Helianthus annuus L. are exposed to water deficit stress. Therefore, the investigation of irrigation management in the farm conditions is a necessary element for increasing irrigation efficiency and decreasing water losses. The objective of present study was to investigate the effect of different rates of super absorbent polymer and levels of water stress on water use efficiency (WUE, yield and some morphological traits of sunflower (cultivar Master. Factorial experiment was carried out in completely randomized design with 3 replications. Factors were water stress in three levels (irrigation in 0.75; 0.50 and 0.25% of field capacity and super absorbent polymer in five levels (0; 0.75; 0.150; 2.25; 3 g/kg of soil. Super absorbent polymer was added in eight leaves stage of sunflower to pots in deepness of roots development. Water stress treatment was also applied in this growth stage of sunflower. For stress application, pots were weighted every day and irrigated when soil water received to 0.75; 0.50 and 0.25 of field capacity, respectively. The results of ANOVA indicated that the effect of different rates of super absorbent polymer and different rates of consumed water in all traits were significant. ANOVA also revealed that the interactive effects of two mentioned factors were significant except for seed yield trait. Polynomial model based on the ANOVA results was fitted for each trait. The results indicated that water stress significantly convert in decreasing the number of leaves per plant, chlorophyll content, 100 weight of seeds, seed yield and WUE in sunflower, whereas the application of super absorbent polymer moderated the negative effect of deficit irrigation, especially in high rates of polymer (2.25 and 3 g/kg of soil. The above mentioned rates of polymer have the best effect to all characteristics of sunflower in all levels of water stress treatment. The findings

  1. Water and temperature stresses impact canola (Brassica napus L.) fatty acid, protein and yield over nitrogen and sulfur

    Science.gov (United States)

    Interactive effects of weather and soil nutrient status often control crop productivity. An experiment was conducted to determine effects of N and S fertilizer rate, soil water, and atmospheric temperature on canola fatty acid (FA), total oil, protein and grain yield. Nitrogen and S were assessed in...

  2. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    NARCIS (Netherlands)

    Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Yang, Liu; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem; Zhang, Lizhen

    2017-01-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region

  3. Effect of water stress on growth, yield and water use efficiency of berseem (Trifolium alexandrium in Tadla

    Directory of Open Access Journals (Sweden)

    B. Bouazzama

    2018-01-01

    Full Text Available The study of crop response to water deficit is important in areas where water resources are limited. This study was carried out over the period 2008-2011 in order to study the effect of water deficit on the productivity of berseem in the Tadla region. Four water regimes (100%, 80%, 60% and 40% ETc were compared under both flood and drip irrigation techniques. Observations were made on the soil, biomass at each cut and root system. The results showed that the average annual maximum yield obtained was 16.2 t/ha. Reductions in yields by applying 60% of water inputs are 40% and 42% in 2009/10 and 2010/11, respectively. The contribution of cycles without irrigation to annual biomass yield varies from 35% under 100% ETc to 52% under 40% ETc. Water use efficiency of berseem over the over the entire crop period is 3.37 kg/m3. The maximum average yield obtained under drip irrigation was 15.7 t/ha. It was obtained with a water supply of 411 mm which allowed a saving of 57% of water supply versus flood irrigation technique.

  4. Quantifying the effect of heat stress on daily milk yield and monitoring dynamic changes using an adaptive dynamic model

    NARCIS (Netherlands)

    Andre, G.; Engel, B.; Berentsen, P.B.M.; Vellinga, T.V.; Oude Lansink, A.G.J.M.

    2011-01-01

    Automation and use of robots are increasingly being used within dairy farming and result in large amounts of real time data. This information provides a base for the new management concept of precision livestock farming. From 2003 to 2006, time series of herd mean daily milk yield were collected on

  5. An experimental and numerical investigation into the single-fibre fragmentation test : stress transfer by a locally yielding matrix

    NARCIS (Netherlands)

    van den Heuvel, P.W.J.; Hogeweg, B.; Peijs, A.A.J.M.

    1997-01-01

    Single-fibre fragmentation tests on carbon/epoxy microcomposites were performed using carbon fibres with surface treatment levels varying from 0 to 200% of the commercial fibre surface treatment, i.e. 100%. Polarized light microscopy showed substantial local matrix yielding near the fibre-matrix

  6. A late embryogenesis abundant protein HVA1 regulated by an inducible promoter enhances root growth and abiotic stress tolerance in rice without yield penalty.

    Science.gov (United States)

    Chen, Yi-Shih; Lo, Shuen-Fang; Sun, Peng-Kai; Lu, Chung-An; Ho, Tuan-Hua D; Yu, Su-May

    2015-01-01

    Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress-inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water-use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin-dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress-suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  7. The Effect of Vermicompost and Mycorrhizal Inoculation on Grain Yield and some Physiological Characteristics of Soybean (Glycine max L. under Water Stress Condition

    Directory of Open Access Journals (Sweden)

    Elham Jahangiri nia

    2017-08-01

    Full Text Available Introduction Moisture limitation is considered as one of the important limiting factors in soybean growth. Drought stress affects different aspects of soybean growth through making anatomical, physiological and biochemical changes (Tarumingkeng & Coto, 2003. Under dry tension condition, there will be a disturbance in transmitting nutrients, but some useful soil fungi such as mycorrhiza improve production of crops under stress through forming colonies in the root and boosting water and nutrient absorption (Al-Karaki et al., 2004. Using vermicompost in sustainable agriculture strengthens support and activities of beneficial soil microorganisms (such as mycorrhizal fungi and phosphate solubilizing microorganisms in order to provide nutrients required by plants like nitrogen, phosphorus and soluble potassium as well as improving the growth and performance of the crops (Arancon et al., 2004. Materials and methods In order to investigate the effects of vermicompost and mycorrhiza fertilizers on grain yield and some physiological characteristics of soybean under water stress condition an experiment was conducted at Agricultural Research Center of Khorramabad during 2013. The field experiment was carried out based on a randomized complete blocks design arranged in split-plot with four replications. The experiment treatments including irrigation in three levels (after 60, 120 and 180 mm evaporation from pan class A pan, nutrient management in six levels (non-use of vermicompost and mycorhiza fertilizer, inoculated with mycorrhiza fertilizer, consumption of 5 and 10 t.ha-1 vermicompost, consumption of 5 and 10 t.ha-1 vermicompost with mycorrhiza were respectively as the main plots and sub. In current study, RWC, LAI, SPAD were measured during 59 days after planting at the beginning of podding of the control treatment. The temperature of plant leaves were measured by the thermometer (model TM-958 LUTRON infrared Thermometers. To analyze the growth of

  8. Material Properties Test to Determine Ultimate Strain and True Stress-True Strain Curves for High Yield Steels

    Energy Technology Data Exchange (ETDEWEB)

    K.R. Arpin; T.F. Trimble

    2003-04-01

    This testing was undertaken to develop material true stress-true strain curves for elastic-plastic material behavior for use in performing transient analysis. Based on the conclusions of this test, the true stress-true strain curves derived herein are valid for use in elastic-plastic finite element analysis for structures fabricated from these materials. In addition, for the materials tested herein, the ultimate strain values are greater than those values cited as the limits for the elastic-plastic strain acceptance criteria for transient analysis.

  9. Role of aquaporins in determining transpiration and photosynthesis in water-stressed plants: crop water-use efficiency, growth and yield.

    Science.gov (United States)

    Moshelion, Menachem; Halperin, Ofer; Wallach, Rony; Oren, Ram; Way, Danielle A

    2015-09-01

    The global shortage of fresh water is one of our most severe agricultural problems, leading to dry and saline lands that reduce plant growth and crop yield. Here we review recent work highlighting the molecular mechanisms allowing some plant species and genotypes to maintain productivity under water stress conditions, and suggest molecular modifications to equip plants for greater production in water-limited environments. Aquaporins (AQPs) are thought to be the main transporters of water, small and uncharged solutes, and CO2 through plant cell membranes, thus linking leaf CO2 uptake from the intercellular airspaces to the chloroplast with water loss pathways. AQPs appear to play a role in regulating dynamic changes of root, stem and leaf hydraulic conductivity, especially in response to environmental changes, opening the door to using AQP expression to regulate plant water-use efficiency. We highlight the role of vascular AQPs in regulating leaf hydraulic conductivity and raise questions regarding their role (as well as tonoplast AQPs) in determining the plant isohydric threshold, growth rate, fruit yield production and harvest index. The tissue- or cell-specific expression of AQPs is discussed as a tool to increase yield relative to control plants under both normal and water-stressed conditions. © 2014 John Wiley & Sons Ltd.

  10. Unwinding after high salinity stress: Pea DNA helicase 45 over- expression in tobacco confers high salinity tolerance without affecting yield (abstract)

    International Nuclear Information System (INIS)

    Tuteja, N.

    2005-01-01

    Soil salinity is an increasing threat for agriculture and is a major factor in reducing plant productivity; therefore, it is necessary to obtain salinity-tolerant varieties. A typical characteristic of soil salinity is the induction of multiple stress- inducible genes. Some of the genes encoding osmolytes, ion channels or enzymes are able to confer salinity-tolerant phenotypes when transferred to sensitive plants. As salinity stress affects the cellular gene-expression machinery, it is evident that molecules involved in nucleic acid processing including helicases, are likely to be affected as well. DNA helicases unwind duplex DNA and are involved in replication, repair, recombination and transcription while RNA helicases unfold the secondary structures in RNA and are involved in transcription, ribosome biogenesis and translation initiation. We have earlier reported the isolation of a pea DNA helicase 45 (PDH45) that exhibits striking homology with eIF-4A (Plant J. 24:219-230,2000). Here we report that PDH45 mRNA is induced in pea seedlings in response to high salt and its over- expression driven by a constitutive CAMV-355-promoter in tobacco plants confers salinity tolerance, thus suggesting a new pathway for manipulating stress tolerance in crop plants. The T0 transgenic plants showed high-levels of PDH45 protein in normal and stress conditions, as compared to wild type (WT) plants. The T0 transgenics also showed tolerance to high salinity as tested by a leaf disc senescence assay. The T1 transgenics were able to grow to maturity and set normal viable seeds under continuous salinity stress, without any reduction in plant yield, in terms of seed weight. Measurement of Na/sup +/ ions in different parts of the plant showed higher accumulation in the old leaves and negligible in seeds of T1 transgenic lines as compared with the WT plants. The possible mechanism of salinity tolerance will be discussed. Over-expression of PDH45 provides a possible example of the

  11. The Effect of Phosphorus and Zinc Fertilizers on Nutrient Content and Essential Oil Yield of German Chamomile under Drought Stress (Matricaria recutita L.

    Directory of Open Access Journals (Sweden)

    M. Ghaedi Jeshni

    2016-07-01

    Full Text Available Introduction: The German chamomile (Matricaria recutita L. is mainly cultivated for essential oil. Nowadays, it is a highly favored and much-used medicinal plant in reqular and traditional medicine. Water deficit is one of the most important limiting factors on crops production in arid and semi-arid regions (Sharafi et al. 2002. Drought stress limits the growth of plants by reducing water content of tissues and causes some metabolic and physiological changes. On the other hand, the availability of nutrients in the soil is affected by drought stress. Thus, nutritional management of plants under drought stress conditions is one of the most important factors in crop production. A better understanding of the role of nutrients in plant resistance to drought is associated with improvement of fertilizer management in arid and semi-arid areas. Our objectives were to investigate the effects of phosphorus and zinc fertilizers on nutrient content and essential oil yield of German chamomile under drought stress. Material and Methods: The experiment was conducted in split plot factorial based on randomized complete block design with three replications at Research farm of University of Zabol in 2013. Drought stress consisted of three levels 75% (control, 50% (mild stress and 25% of field capacity (severe stress as main plots, and factorial combinations of three triple superphosphate fertilizer (CaH4P2O8 levels (0, 150, and 300 kg ha-1 and two zinc sulphate fertilizer (ZnSO4H2O levels (0 and 30 kg ha-1 as sub plots (the fertilizers were applied before planting time. The seeds were sown at 20 cm apart in rows 40 cm wide, on first half of March 2013. Drought stress levels were determined by the Time Domain Reflectometry (TDR. The success of chamomile cultivation as a commercial venture lies in how efficiently and effectively one can collect the flowers at the right stage during the peak flowering season extending over a period of 3–6 weeks. So, flowers were

  12. Soil precompression stress, penetration resistance and crop yields in relation to differently-trafficked, temperate-region sandy loam soils

    DEFF Research Database (Denmark)

    Schjønning, Per; Lamandé, Mathieu; Munkholm, Lars Juhl

    2016-01-01

    . Undisturbed soil cores were used for quantifying the precompression stress (spc) of non-compacted soil. Tractor-trailer combinations for slurry application with wheel loads of 3, 6 and 8 Mg (treatments M3, M6, M8) were used for the experimental traffic in the spring at field-capacity. For one additional...

  13. Energy-Based Yield Criteria for Orthotropic Materials, Exhibiting Strength-Differential Effect. Specification for Sheets under Plane Stress State

    Directory of Open Access Journals (Sweden)

    Szeptyński P.

    2017-06-01

    Full Text Available A general proposition of an energy-based limit condition for anisotropic materials exhibiting strength-differential effect (SDE based on spectral decomposition of elasticity tensors and the use of scaling pressure-dependent functions is specified for the case of orthotropic materials. A detailed algorithm (based on classical solutions of cubic equations for the determination of elastic eigenstates and eigenvalues of the orthotropic stiffness tensor is presented. A yield condition is formulated for both two-dimensional and three-dimensional cases. Explicit formulas based on simple strength tests are derived for parameters of criterion in the plane case. The application of both criteria for the description of yielding and plastic deformation of metal sheets is discussed in detail. The plane case criterion is verified with experimental results from the literature.

  14. Predicting yield-stress anomalies in L12 alloys: Ni3Ge-Fe3Ge pseudo-binaries

    International Nuclear Information System (INIS)

    Liu, J.B.; Johnson, D.D.; Smirnov, A.V.

    2005-01-01

    The L1 2 -based pseudo-binary (Ni 1-c Fe c ) 3 Ge is an ideal system to study yield-strength anomaly and its origin as it has a solid-solution phase vs. c and Ni 3 Ge exhibits an anomaly while Fe 3 Ge does not. Using two ab initio electronic-structure techniques, we calculate the planar-fault energies on the γ-surface, i.e., antiphase boundaries (APB) and stacking faults, both complex and superlattice intrinsic (SISF), for (Ni 1-c Fe c ) 3 Ge as a function of c. Generally, we use the fault energies combined with elasticity theory to predict occurrence/loss of the yield-strength anomaly and show that the loss of anomaly occurs due to APB(1 1 1)-to-SISF(1 1 1) instability. Assessing the stability of APB(1 1 1) on the γ-surface within linear elasticity theory, we predict the transition from anomalous to normal temperature dependence of yield strength for c ∼≥ 0.35 (or 26 at.% Fe), as is observed, after which type-II, rather than type-I, dissociation is energetically favorable. Hence, first-principles calculations can predict reliably the existence/loss of anomalous yield-strength. Finally, we show that (0 0 1) and (1 1 1) APB energies of the binaries and pseudo-binaries agree quantitatively with measured values when chemical antisite disorder, intrinsic to the samples characterized, is included, whereas they are too large by a factor of two in perfect L1 2 . We investigate three types of disorder: thermal and off-stoichiometric antisites, as well as chemical disorder vs. Fe-content in pseudo-binaries

  15. Role of nitric oxide in cadmium-induced stress on growth, photosynthetic components and yield of Brassica napus L.

    Science.gov (United States)

    Jhanji, Shalini; Setia, R C; Kaur, Navjyot; Kaur, Parminder; Setia, Neelam

    2012-11-01

    Experiments were carried out to study the effect of cadmium (Cd) and exogenous nitric oxide (NO) on growth, photosynthetic attributes, yield components and structural features of Brassica napus L. (cv. GSL 1). Cadmium in the growth medium at different levels (1, 2 and 4 Mm) retarded plant growth viz. shoot (27%) and root (51%) length as compared to control. The accumulation of total dry matter and its partitioning to different plant parts was also reduced by 31% due to Cd toxicity. Photosynthetic parameters viz., leaf area plant(-1) (51%), total Chl (27%), Chl a / Chl b ratio (22%) and Hill reaction activity of chloroplasts (42%) were greatly reduced in Cd-treated plants. Cd treatments adversely affected various yield parameters viz., number of branches (23) and siliquae plant(-1) (246), seed number siliqua(-1) (10.3), 1000-seed weight (2.30g) and seed yield plant(-1) (7.09g). Different Cd treatments also suppressed the differentiation of various tissues like vessels in the root with a maximum inhibition caused by 4mM Cd. Exogenous application of nitric oxide (NO) improved the various morpho-physiological and photosynthetic parameters in control as well as Cd-treated plants.

  16. RESPONSE OF CHILE PEPPER (Capsicum annuum L. TO SALT STRESS AND ORGANIC AND INORGANIC NITROGEN SOURCES: I.GROWTH AND YIELD

    Directory of Open Access Journals (Sweden)

    Marco Antonio Huez Lopez

    2010-10-01

    Full Text Available The effect of two sources of nitrogen on plant growth, and fruit yield of chile pepper (Capsicum annuum L. cv. Sandia grown in greenhouse to increased salinity   were evaluated. An organic source extracted from grass clippings in rates of 120 and 200 kg N ha-1, and another inorganic (ammonium nitrate in rate of 120 kg ha-1 were combined with low, moderate and high (1.5, 4.5, and 6.5 dS m-1 salinity levels arranged in a randomized complete block design replicated four times. Salinity treatments reduced dry matter production, leaf area, relative growth rate and net assimilation rate but increased leaf area ratio. Mean fresh fruit yields decreased for each N rate and source combinations as soil salinity increased. The organic fertilizer produced higher fruit yields tan the inorganic fertilizer. The highest fruit yield was obtained with the increased rate of organic N.    The fruit number was more affected by salinity than the individual fruit weight. This organic fertilizer may be an effective N source for chile pepper and other vegetable crops grown under non- and salt-stressed conditions.

  17. Drought Stress Effect during Different Growth Stages on Yield, Osmolites and Photosynthetic Pigments Accumulation of Grain Sorghum Genotypes (Sorghum bicolor L.

    Directory of Open Access Journals (Sweden)

    A Azari Nasrabad

    2017-12-01

    Full Text Available Introduction Osmotic adjustment in plants can be achieved by the accumulation of compatible solution or metabolites. These compounds are known as compatible metabolites that accumulate naturally in tolerant plants due to non-interference in the normal metabolic response of plants to adapt or supplement. Proline, soluble sugars and other metabolites accumulation that are involved in osmotic adjustment have been reported for various plants. Different studies show that water absorption in sorghum plant, is due to osmotic adjustment and appropriate and fairly extensive root system. Moreover, there are some differences from genotype to genotype regarding the osmolites accumulation under drought stress conditions. Thus, the aim of this study was to investigate the effects of drought in the vegetative and reproductive growth stages on yield, its components and biochemical traits in grain sorghum genotypes. Materials and Methods In order to evaluate the effect of water stress on grain yield and its components and some biochemical traits in grain sorghum genotypes (Sorghum bicolor L., a field experiment as a split plot design was carried out with 3 replications in 2014 at the research farm of the southern Khorasan Agriculture and natural resources research and education center. Water stress treatments including normal irrigation (control, irrigation cut off in vegetative growth stage (emergence of terminal leaf as rolled and irrigation cut off in generative growth stage (50% of plants in start of flowering as the main plot and 10 genotypes of sorghum including KGS29, MGS2, Sepideh, KGFS27, MGS5, KGFS5, KGFS17, KGFS13 and KGFS30 were considered as sub plots. Each plot consists of 4 rows with a length of 6 m and row spacing of 60 cm, between plants on row was 10 cm. In addition, between each plot and the adjacent plot a row was considered to side effect reduction. To determine the yield components of each plot, half a meter in length was harvested and the

  18. Effects of drought stress and bio-fertilizers inoculation on growth, essential oil yield and constituents of thyme (Thymus vulgaris L.

    Directory of Open Access Journals (Sweden)

    roghayeh mohammadpour vashvaei

    2016-05-01

    Full Text Available Thyme (Thymus vulgaris L. is perennial aromatic shrub belonging to the mint family which has anti-spasmodic, antiseptic, carminative, anti-cough, sputum and antioxidant properties. In order to study the effects of drought stress and bio-fertilizer on plant growth, essential oil yield and constituents of thyme plant, an experiment was conducted in a split plot based on randomized complete block design with two replications, at the Research Farm of Zabol University, during growing season of 2012 and 2013. Main plots consisted of irrigation with 30, 50, 70 and 90% field capacity and subplots including plant inoculation with nitroxin, bio-phosphorus and mycorrhiza. Plant traits such as plant height, fresh and dry weight of herb per plant, essential oil percentage, yield and constituents of Thyme were measured. Effects of drought stress, bio-fertilizer and their interactions on all studied traits were significant at the 1% probability level. The highest plant height (35.09 cm, fresh and dry weight of herb per plant (103.52 and 43,27 g.plant-1, respectively and essential oil yield (0.350 ml.plant-1 belong to treatment of irrigation with 90% field capacity and nitroxin bio-fertilizer. The maximum essential oil percentage with 0.413% was obtained by irrigation with 70% field capacity and nitroxin bio-fertilizer. Fresh weight of herb per plant was the most crucial component in determining essential oil yield in Thyme. Plants irrigated with 70% filed capacity gave the highest relative percentage of thymol, which reached 71.32, 50.68 and 47.71% in nitroxin, biophosphorus and mycorrhiza biofertilizer, respectively. This effect was accompanied with decrease in -cymene content. Inoculation with nitroxin bio-fertilizer as compared to other fertilizers could further amend drought stress and improved the plant growth, essential oil percentage and yield and phenolic compound thymol of Thyme. Thus, it appears that in order to achieve sustainable agriculture

  19. The scaling of stress distribution under small scale yielding by T-scaling method and application to prediction of the temperature dependence on fracture toughness

    International Nuclear Information System (INIS)

    Ishihara, Kenichi; Hamada, Takeshi; Meshii, Toshiyuki

    2017-01-01

    In this paper, a new method for scaling the crack tip stress distribution under small scale yielding condition was proposed and named as T-scaling method. This method enables to identify the different stress distributions for materials with different tensile properties but identical load in terms of K or J. Then by assuming that the temperature dependence of a material is represented as the stress-strain relationship temperature dependence, a method to predict the fracture load at an arbitrary temperature from the already known fracture load at a reference temperature was proposed. This method combined the T-scaling method and the knowledge “fracture stress for slip induced cleavage fracture is temperature independent.” Once the fracture load is predicted, fracture toughness J c at the temperature under consideration can be evaluated by running elastic-plastic finite element analysis. Finally, the above-mentioned framework to predict the J c temperature dependency of a material in the ductile-to-brittle temperature distribution was validated for 0.55% carbon steel JIS S55C. The proposed framework seems to have a possibility to solve the problem the master curve is facing in the relatively higher temperature region, by requiring only tensile tests. (author)

  20. Correlation of Yield Stress And Microhardness in 08cr16ni11mo3 Irradiated To High Dose In The Bn-350 Fast Reactor

    International Nuclear Information System (INIS)

    Maksimkin, O.P.; Gusev, M.N.; Tivanova, O.S.; Silnaygina, N.S.; Garner, Francis A.

    2006-01-01

    The relationship between values of the microhardness and the engineering yield stress in steel 08Cr16Ni11Mo3 (Russian analog of AISI 316) heavily irradiated in the BN-350 reactor has been experimentally derived. It agrees very well with the previously published correlation developed by Toloczko for unirradiated 316 in a variety of cold-work conditions. Even more importantly, when the correlation is derived in the K δ format where the correlation involves changes in the two properties, we find excellent agreement with a universal K δ correlation developed by Busby and coworkers. With this K δ correlation, one can predict the value of yield stress in irradiated material based on measured values of microhardness. The technique is particularly suitable when the material of interest is in an inconvenient location or configuration, or when significant gradients in mechanical properties are anticipated over small dimensions. This approach makes it possible to reduce the labor input and risk when conducting such work. It appears that the derived correlation is equally applicable to both Russian and Western austenitic steel, and also in both irradiated and unirradiated conditions. Additionally, this report points out that microhardness measurements must take into account that high temperature sodium exposure alters the metal surface to produce ferrite, and therefore the altered layers should be removed prior to testing

  1. Lowering rumen-degradable protein maintained energy-corrected milk yield and improved nitrogen-use efficiency in multiparous lactating dairy cows exposed to heat stress.

    Science.gov (United States)

    Kaufman, J D; Kassube, K R; Ríus, A G

    2017-10-01

    The objective of this study was to examine the effect of reducing rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) proportions on feed intake, milk production, and N-use efficiency in primiparous and multiparous cows exposed to warm climates. Eighteen primiparous and 30 multiparous mid-lactation Holstein cows were used in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Cows were randomly assigned to 1 of 4 dietary treatments formulated to contain 2 proportions of RDP (10 and 8%) and 2 proportions RUP (8 and 6%) of dry matter (DM) indicated as follows: (1) 10% RDP, 8% RUP; (2) 8% RDP, 8% RUP; (3) 10% RDP, 6% RUP; and (4) 8% RDP, 6% RUP. Protein sources were manipulated to obtain desired RDP and RUP proportions. Diets were isoenergetic and contained 50% forage and 50% concentrate (DM basis). Cows were individually fed the 10% RDP, 8% RUP diet 3 wk before treatment allocation. Cows were exposed to the prevailing Tennessee July and August temperature and humidity in a freestall barn with no supplemental cooling. Main effects and their interaction were tested using the Mixed procedure of SAS (least squares means ± standard error of the mean; SAS Institute Inc., Cary, NC). Observed values of nutrient intake and milk production were used to obtain NRC (2001) model predictions. Cows showed signs of heat stress throughout the study. Reducing from 10 to 8% RDP decreased dry matter intake (DMI; 0.9 kg/d) at 8% RUP, but increased DMI (2.6 kg/d) at 6% RUP in primiparous cows. Reducing from 10 to 8% RDP decreased milk yield (10%) at 8% RUP, but increased yield (14%) at 6% RUP. Treatments did not affect yield of energy-corrected milk. For multiparous cows, treatments did not affect DMI. Reducing from 10 to 8% RDP decreased yield of energy-corrected milk (3.4%) at 8% RUP, but increased yield (8.8%) at 6% RUP. Reducing from 10 to 8% RDP and 8 to 6% RUP both increased N-use efficiency for primiparous and multiparous cows. The NRC

  2. On the stability of the production of bubbles in yield-stress fluid using flow-focusing and T-junction devices

    Science.gov (United States)

    Laborie, B.; Rouyer, F.; Angelescu, D. E.; Lorenceau, E.

    2016-06-01

    We investigate experimentally the stability of bubble production in yield-stress fluids (YSF) and highly viscous silicone oil, using flow-focusing and T-junction devices. When the exit channel is initially pre-filled with the fluid and the gas is pressure-driven, the production is highly unstable, despite a regular frequency of bubble production in the junction. As observed for pressure-driven bubble trains in Newtonian fluids, we report that two mechanisms can explain these observations: (i) drastic reduction of the hydrodynamic pressure drop along the channel during the transient bubble production, which induces a rapid increase of the gas flow rate and (ii) thin film deposition resulting in a cascade of plug break-up and bubble coalescence. While the drastic reduction of the pressure drop is inevitable in such two-phase flows, we show that modifying the surfaces of the channel can help to stabilize the system when the continuous phase is a YSF. To do so, we measure the thickness of the film deposited on the channel wall for rough and smooth channels. Our results are rationalized by introducing the inverse of the Bingham number Bi-1 comparing the viscous stress to the yield stress. For Bi-1 ≥ 1, a fast fluidization process associated to efficient deposition of YSF on the channel wall leads to a rapid destabilization of bubble production. However, for Bi-1 < 1, the deposition driven by capillarity can be hindered by the wall-slip induced by the existence of the yield stress: the thickness of the deposited film is very thin and corresponds to the equivalent roughness of the channels. It is typically 40 μm thick for rough surfaces and below the limit of resolution of our set-up for smooth surfaces. In this regime of Bi-1 and for smooth surfaces, the length of the plugs barely vanishes, thus the start-up flow is less prone to destabilization. These results therefore potentially open routes to steady production of aerated YSF on smooth channels in the regime of

  3. Effects of timing and severity of salinity stress on rice (Oryza sativa L.) yield, grain composition, and starch functionality.

    Science.gov (United States)

    Thitisaksakul, Maysaya; Tananuwong, Kanitha; Shoemaker, Charles F; Chun, Areum; Tanadul, Orn-u-ma; Labavitch, John M; Beckles, Diane M

    2015-03-04

    The aim of this work was to examine agronomic, compositional, and functional changes in rice (Oryza sativa L. cv. Nipponbare) grains from plants grown under low-to-moderate salinity stress in the greenhouse. Plants were grown in sodium chloride-containing soil (2 or 4 dS/m(2) electrical conductivity), which was imposed 4-weeks after transplant (called Seedling EC2 and EC4) or after the appearance of the anthers (called Anthesis EC2 and EC4). The former simulates field conditions while the latter permits observation of the isolated effect of salt on grain filling processes. Key findings of this study are the following: (i) Plants showed adaptive responses to prolonged salt treatment with no negative effects on grain weight or fertility. Seedling EC2 plants had more panicles and enhanced caryopsis dimensions, while surprisingly, Seedling EC4 plants did not differ from the control group in the agronomic parameters measured. (ii) Grain starch increased in Seedling EC4 (32.6%) and Anthesis EC2 (39%), respectively, suggesting a stimulatory effect of salt on starch accumulation. (iii) The salinity treatment of 2 dS/m(2) was better tolerated at anthesis than the 4 dS/m(2) treatment as the latter led to reduced grain weight (28.8%) and seed fertility (19.4%) and compensatory increases in protein (20.1%) and nitrogen (19.8%) contents. (iv) Although some salinity treatments led to changes in starch content, these did not alter starch fine structure, morphology, or composition. We observed no differences in reducing sugar and amylose content or starch granule size distribution among any of the treatments. The only alterations in starch were limited to small changes in thermal properties and glucan chain distribution, which were only seen in the Anthesis EC4 treatment. This similarity of compositional and functional features was supported by multivariate analysis of all variables measured, which suggested that differences due to treatments were minimal. Overall, this study

  4. A note on hypoplastic yielding

    OpenAIRE

    Nader, José Jorge

    2010-01-01

    This note discusses briefly the definition of yield surface in hypoplasticity in connection with the physical notion of yielding. The relation of yielding with the vanishing of the material time derivative of the stress tensor and the vanishing of the corotational stress rate is investigated.

  5. Effects of water restriction following feeding on nutrient digestibilities, milk yield and composition and blood hormones in lactating Holstein cows under heat stress conditions

    Directory of Open Access Journals (Sweden)

    Jalil Ghassemi Nejad

    2015-08-01

    Full Text Available The effects of water restriction following feeding under heat stress conditions on nutrient digestibilities, milk yield and composition and some blood hormones in lactating Holstein cows were evaluated. The design was completely randomized with 30 high producing lactating Holstein cows (80.8±40.5 DIM which were assigned to two treatment groups (15 cows per treatment. Treatments were free access to water (FAW and 2 h water restriction (2hWR following feeding. Average temperature-humidity index (THI in the farm was over 80 throughout the experiment which defines heat stress conditions. Neutral detergent fibre, organic matter and ether extract digestibilities increased by water restriction (P0.05. Water intake was recorded daily during the digestibility period and was not different between FAW and 2hWR group (P>0.05. Fat corrected milk was higher in 2hWR group than FAW group (P0.05. Somatic cell counts were greater in 2hWR than FAW group (P0.05. Blood prolactin and growth hormone were higher in 2hWR group than the FAW group (P<0.05. It is concluded that water restriction for 2 hours following feeding improved nutrient digestibility of some dietary components and increased milk fat percentage in lactating Holstein cows under heat stress conditions.

  6. Core stress distribution of phase shifting multimode polymer optical fiber

    International Nuclear Information System (INIS)

    Furukawa, Rei; Matsuura, Motoharu; Nagata, Morio; Mishima, Kenji; Inoue, Azusa; Tagaya, Akihiro; Koike, Yasuhiro

    2013-01-01

    Poly-(methyl methacrylate-co-benzyl methacrylate) polarization-maintaining optical fibers are known for their high response to normal stress. In this report, responses to higher stress levels up to 0.45 MPa were investigated. The stress amplitude and direction in the fiber cross section were calculated and analyzed with a coincident mode-field obtained from the near-field pattern. The stress amplitude varies significantly in the horizontal direction and is considered to create multiple phases, explaining the measurement results. To investigate possible permanent deformation, the core yield point profile was analyzed. Although it largely exceeds the average applied stress, the calculated stress distribution indicates that the core could partially experience stress that exceeds the yield point

  7. Generalization of the existing relations between microstructure and yield stress from ferrite-pearlite to high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Iza-Mendia, A., E-mail: aiza@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain); Gutierrez, I. [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain)

    2013-01-20

    A series of available equations allows the yield and the tensile strength of low carbon ferrite-pearlite microstructures to be expressed as a function of the optical grain size, steel composition and interstitials in solution. Over the years, as the complexity of steel microstructures has increased, some additional terms have been added to account for precipitation and forest dislocation contributions. In theory, this opens the door for an extension of these equations to bainitic microstructures. Nevertheless, there is a series of difficulties that needs to be overcome in order to improve prediction accuracy. In the present work, different microstructures (ferrite-pearlite, bainite, quenched, and quenched and tempered) were produced and tension tested in a C-Mn-Nb steel. Optical microscopy and EBSD (Electron Back Scattered Diffraction) were applied and the results were compared as a function of the tolerance angle. Based on this work, an adaptation to Pickering's equation is proposed, including its extension to other microstructures rather than ferrite-pearlite.

  8. Benzoate-induced stress enhances xylitol yield in aerobic fed-batch culture of Candida mogii TISTR 5892.

    Science.gov (United States)

    Wannawilai, Siwaporn; Sirisansaneeyakul, Sarote; Chisti, Yusuf

    2015-01-20

    Production of the natural sweetener xylitol from xylose via the yeast Candida mogii TISTR 5892 was compared with and without the growth inhibitor sodium benzoate in the culture medium. Sodium benzoate proved to be an uncompetitive inhibitor in relatively poorly oxygenated shake flask aerobic cultures. In a better controlled aerobic environment of a bioreactor, the role of sodium benzoate could equally well be described as competitive, uncompetitive or noncompetitive inhibitor of growth. In intermittent fed-batch fermentations under highly aerobic conditions, the presence of sodium benzoate at 0.15gL(-1) clearly enhanced the xylitol titer relative to the control culture without the sodium benzoate. The final xylitol concentration and the average xylitol yield on xylose were nearly 50gL(-1) and 0.57gg(-1), respectively, in the presence of sodium benzoate. Both these values were substantially higher than reported for the same fermentation under microaerobic conditions. Therefore, a fed-batch aerobic fermentation in the presence of sodium benzoate is promising for xylitol production using C. mogii. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Increased biomass, seed yield and stress tolerance is conferred in Arabidopsis by a novel enzyme from the resurrection grass Sporobolus stapfianus that glycosylates the strigolactone analogue GR24.

    Directory of Open Access Journals (Sweden)

    Sharmin Islam

    Full Text Available Isolation of gene transcripts from desiccated leaf tissues of the resurrection grass, Sporobolus stapfianus, resulted in the identification of a gene, SDG8i, encoding a Group 1 glycosyltransferase (UGT. Here, we examine the effects of introducing this gene, under control of the CaMV35S promoter, into the model plant Arabidopsis thaliana. Results show that Arabidopsis plants constitutively over-expressing SDG8i exhibit enhanced growth, reduced senescence, cold tolerance and a substantial improvement in protoplasmic drought tolerance. We hypothesise that expression of SDG8i in Arabidopsis negatively affects the bioactivity of metabolite/s that mediate/s environmentally-induced repression of cell division and expansion, both during normal development and in response to stress. The phenotype of transgenic plants over-expressing SDG8i suggests modulation in activities of both growth- and stress-related hormones. Plants overexpressing the UGT show evidence of elevated auxin levels, with the enzyme acting downstream of ABA to reduce drought-induced senescence. Analysis of the in vitro activity of the UGT recombinant protein product demonstrates that SDG8i can glycosylate the synthetic strigolactone analogue GR24, evoking a link with strigolactone-related processes in vivo. The large improvements observed in survival of transgenic Arabidopsis plants under cold-, salt- and drought-stress, as well as the substantial increases in growth rate and seed yield under non-stress conditions, indicates that overexpression of SDG8i in crop plants may provide a novel means of increasing plant productivity.

  10. Dietary Supplementation of Chromium Can Alleviate Negative Impacts of Heat Stress on Performance, Carcass Yield, and Some Blood Hematology and Chemistry Indices of Growing Japanese Quail.

    Science.gov (United States)

    El-Kholy, Mohamed Soliman; El-Hindawy, Mohamed Mohamed; Alagawany, Mahmoud; Abd El-Hack, Mohamed Ezzat; El-Sayed, Sabry Abd El-Gawad Abd El-Halim

    2017-09-01

    The main objective of this work was to investigate the impact of dietary chromium supplementation on growth indices, carcass yield, and some hematological and biochemical blood parameters of growing Japanese quails subjected to heat stress. A total of 360 unsexed 2-week-old Japanese quail chicks were used in a 2 × 3 factorial arrangement that had two ambient temperatures (23 ± 2 and 33 ± 2 °C) and three dietary chromium (0.00, 500, and 1000 μg Cr/kg diet as chromium picolinate). For induction of heat stress, the room temperature was set at 33 ± 2 °C from 2 to 6 weeks of age. Results showed that body weight, body weight gain, and feed intake were decreased for birds subjected to heat stress condition during 2 to 4 and 2 to 6 weeks of age. Feed conversion was not significantly (P > 0.05) affected by high ambient temperature throughout the experiment. Carcass, dressing, liver, and heart percentages were not influenced by the ambient temperature or dietary chromium or their combinations. Significant temperature × chromium combinations were observed for hemoglobin value (P = 0.025) and packed cell volume (P = 0.001). Cholesterol and glucose in plasma were increased (P = 0.004 or 0.022) in quails subjected to heat stress condition. Plasma measurements of total proteins, albumin, globulin, lipids, glucose, and A/G ratio of quail chicks were not influenced (P > 0.05) by chromium, while cholesterol was increased with increasing chromium level (P = 0.033). High ambient temperature or dietary chromium levels or their interactions did not (P > 0.05) affect plasma levels of aspartate transaminase (AST), alanine transaminase (ALT), triiodothyronine (T3), thyroxin (T4), or T3/T4 ratio of growing quails. From these observations, it can be concluded that dietary chromium supplementation of growing Japanese quail subjected to heat stress condition could beneficially affect growth performance and carcasses, as well as modulate the hematological

  11. Dry matter yield, carbon isotope discrimination and nitrogen uptake in silicon and/ or potassium fed chickpea and barley plants grown under water and non-water stress conditions

    International Nuclear Information System (INIS)

    Kurd Ali, F.; Al-Chammaa, M.; Mouasess, A.

    2012-09-01

    A pot experiment was conducted to study the effects of silicon (Si) and/or potassium (K) on dry matter yield, nitrogen uptake and carbon isotope discrimination Δ 13 C in water stressed (FC1) and well watered (FC2) chickpea plants using 15 N and 13 C isotopes. Three fertilizer rates of Si (Si 5 0, Si 1 00 and Si 2 00) and one fertilizer rate of K were used. The results showed that: In chickpeas, it was found, for most of the growth parameters, that Si either alone or in combination with K was more effective to alleviate water stress than K alone. Increasing soil water level from FC1 to FC2 often had a positive impact on values of most studied parameters. The Si 1 00K + (FC1) and Si 5 0K + (FC2) treatments gave high enough amounts of N 2 -fixation, higher dry matter production and greater nitrogen yield. The percent increments of total N 2 -fixed in the above mentioned treatments were 51 and 47% over their controls, respectively. On the other hand, increasing leaves dry matter in response to the solely added Si (Si 5 0K - and Si 1 00K - ) is associated with lower Δ 13 C under both watering regimes. This may indicate that Si fertilization had a beneficial effect on water use efficiency (WUE). Hence, Δ 13 C could be an adequate indicator of WUE in response to the exogenous supply of silicon to chickpea plants. Our results highlight that Si is not only involved in amelioration of growth and in maintaining of water status but it can be considered as an important element for the symbiotic performance of chickpea plants. It can be concluded that synergistic effect of silicon and potassium fertilization with adequate irrigation improves growth and nitrogen fixation in chickpea plants.In barley plants, solely added K or in combination with adequate rate of Si (Si 1 00) were more effective in alleviating water stress and producing higher yield in barley plants than solely added Si. However, the latter nutrient was found to be more effective than the former in producing

  12. Using the quantum yields of photosystem II and the rate of net photosynthesis to moniter high irradiance and temperature stress in chrysanthemum (Dendrantherma grandiflora)

    DEFF Research Database (Denmark)

    Janka, Eshetu; Körner, Oliver; Rosenqvist, Eva

    2015-01-01

    and quantum yield of PSII remaining low until the temperature reaches 28 °C and 2) the integration of online measurements to monitor photosynthesis and PSII operating efficiency may be used to optimise dynamic greenhouse control regimes by detecting plant stress caused by extreme microclimatic conditions.......Under a dynamic greenhouse climate control regime, temperature is adjusted to optimise plant physiological responses to prevailing irradiance levels; thus, both temperature and irradiance are used by the plant to maximise the rate of photosynthesis, assuming other factors are not limiting...... irradiance, the maximum Pn and ETR were reached at 24 °C. Increased irradiance decreased the PSII operating efficiency and increased NPQ, while both high irradiance and temperature had a significant effect on the PSII operating efficiency at temperatures >28 °C. Under high irradiance and temperature, changes...

  13. Correlation of yield stress and microhardness in 08Cr16Ni11Mo3 stainless steel irradiated to high dose in the BN-350 fast reactor

    International Nuclear Information System (INIS)

    Gusev, M.N.; Maksimkin, O.P.; Tivanova, O.V.; Silnaygina, N.S.; Garner, F.A.

    2006-01-01

    The relationship between the microhardness and the engineering yield stress in 08Cr16Ni11Mo3 steel after irradiation in the BN-350 reactor has been experimentally derived and agrees with a previously published correlation developed by Toloczko for unirradiated 316 in a variety of cold-work conditions. Even more importantly, when the correlation is derived in the K Δ format where the correlation involves changes in the two properties, excellent agreement is found with a universal K Δ correlation developed by Busby and coworkers. Additionally, this report points out that microhardness measurements must take into account that sodium exposure at high temperature and neutron fluence alters the metal surface to produce ferrite, and therefore the altered layers should be removed prior to testing

  14. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  15. NaCl stress-induced changes in the essential oil quality and abietane diterpene yield and composition in common sage

    Directory of Open Access Journals (Sweden)

    Taieb Tounekti

    2015-09-01

    Full Text Available Aim: The purpose of this study was to evaluate how increasing NaCl salinity in the medium can affects the essential oils (EOs composition and phenolic diterpene content and yield in leaves of Salvia officinalis L. The protective role of such compounds against NaCl stress was also argued with regard to some physiological characteristics of the plant (water and ionic relations as well as the leaf gas exchanges. Materials and Methods: Potted plants were exposed to increasing NaCl concentrations (0, 50, 75 and 100 mM for 4 weeks during July 2012. Replicates from each treatment were harvested after 0, 2, 3 and 4 weeks of adding salt to perform physiological measurements and biochemical analysis. Results: Sage EOs were rich in manool, viridiflorol, camphor, and borneol. Irrigation with a solution containing 100 mM NaCl for 4 weeks increased considerably 1.8-cineole, camphor and beta-thujone concentrations, whereas lower concentrations (50 and 75 mM had no effects. On the contrary, borneol and viridiflorol concentrations decreased significantly under the former treatment, while manool and total fatty acid concentrations were not affected. Leaf extracts contained also several diterpenes such as carnosic acid (CA, carnosol (CAR and 12- and #1054;-methoxy carnosic acid (MCA. The concentrations and total contents of CA and MCA increased after 3 weeks of irrigation with 75 or 100 mM NaCl. The 50 mM NaCl had no effect on these diterpenes. Our results suggest a protective role for CA against salinity stress. Conclusion: This study may provide ways to manipulate the concentration and yield of some phenolic diterpenes and EOs in sage. In fact soil salinity may favour a directional production of particular components of interest. [J Intercult Ethnopharmacol 2015; 4(3.000: 208-216

  16. Validation of AquaCrop Model for Simulation of Winter Wheat Yield and Water Use Efficiency under Simultaneous Salinity and Water Stress

    Directory of Open Access Journals (Sweden)

    M. Mohammadi

    2016-02-01

    Full Text Available Introduction: FAO AquaCrop model (Raes et al., 2009a; Steduto et al., 2009 is a user-friendly and practitioner oriented type of model, because it maintains an optimal balance between accuracy, robustness, and simplicity; and it requires a relatively small number of model input parameters. The FAO AquaCrop model predicts crop productivity, water requirement, and water use efficiency under water-limiting and saline water conditions. This model has been tested and validated for different crops such as maize, sunflower and wheat (T. aestivum L. under diverse environments. In most of arid and semi-arid regions water shortage is associated with reduction in water quality (i.e. increasing salinity. Plants in these regions in terms of water quality and quantity may be affected by simultaneous salinity and water stress. Therefore, in this study, the AquaCrop model was evaluated under simultaneous salinity and water stress. In this study, AquaCrop Model (v4.0 was used. This version was developed in 2012 to quantify the effects of salinity. Therefore, the objectives of this study were: i evaluation of AquaCrop model (v4.0 to simulate wheat yield and water use efficiency under simultaneous salinity and water stress conditions in an arid region of Birjand, Iran and ii Using different treatments for nested calibration and validation of AquaCrop model. Materials and Methods: This study was carried out as split plot design (factorial form in Birjand, east of Iran, in order to evaluate the AquaCrop model.Treatments consisted of three levels of irrigation water salinity (S1, S2, S3 corresponding to 1.4, 4.5, 9.6 dS m-1 as main plot, two wheat varieties (Ghods and Roshan, and four levels of irrigation water amount (I1, I2, I3, I4 corresponding to 125, 100, 75, 50% water requirement as sub plot. First, AquaCrop model was run with the corresponding data of S1 treatments (for all I1, I2, I3, and I4 and the results (wheat grain yield, average of soil water content

  17. Equity yields

    NARCIS (Netherlands)

    Vrugt, E.; van Binsbergen, J.H.; Koijen, R.S.J.; Hueskes, W.

    2013-01-01

    We study a new data set of dividend futures with maturities up to ten years across three world regions: the US, Europe, and Japan. We use these asset prices to construct equity yields, analogous to bond yields. We decompose the equity yields to obtain a term structure of expected dividend growth

  18. A Combined Precipitation, Yield Stress, and Work Hardening Model for Al-Mg-Si Alloys Incorporating the Effects of Strain Rate and Temperature

    Science.gov (United States)

    Myhr, Ole Runar; Hopperstad, Odd Sture; Børvik, Tore

    2018-05-01

    In this study, a combined precipitation, yield strength, and work hardening model for Al-Mg-Si alloys known as NaMo has been further developed to include the effects of strain rate and temperature on the resulting stress-strain behavior. The extension of the model is based on a comprehensive experimental database, where thermomechanical data for three different Al-Mg-Si alloys are available. In the tests, the temperature was varied between 20 °C and 350 °C with strain rates ranging from 10-6 to 750 s-1 using ordinary tension tests for low strain rates and a split-Hopkinson tension bar system for high strain rates, respectively. This large span in temperatures and strain rates covers a broad range of industrial relevant problems from creep to impact loading. Based on the experimental data, a procedure for calibrating the different physical parameters of the model has been developed, starting with the simplest case of a stable precipitate structure and small plastic strains, from which basic kinetic data for obstacle limited dislocation glide were extracted. For larger strains, when work hardening becomes significant, the dynamic recovery was linked to the Zener-Hollomon parameter, again using a stable precipitate structure as a basis for calibration. Finally, the complex situation of concurrent work hardening and dynamic evolution of the precipitate structure was analyzed using a stepwise numerical solution algorithm where parameters representing the instantaneous state of the structure were used to calculate the corresponding instantaneous yield strength and work hardening rate. The model was demonstrated to exhibit a high degree of predictive power as documented by a good agreement between predictions and measurements, and it is deemed well suited for simulations of thermomechanical processing of Al-Mg-Si alloys where plastic deformation is carried out at various strain rates and temperatures.

  19. Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress.

    Science.gov (United States)

    Porcel, Rosa; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique; Aroca, Ricardo; Garcia, Rosalva; Ruiz-Lozano, Juan Manuel

    2015-08-01

    Rice is the most important food crop in the world and is a primary source of food for more than half of the world population. However, salinity is considered the most common abiotic stress reducing its productivity. Soil salinity inhibits photosynthetic processes, which can induce an over-reduction of the reaction centres in photosystem II (PSII), damaging the photosynthetic machinery. The arbuscular mycorrhizal (AM) symbiosis may improve host plant tolerance to salinity, but it is not clear how the AM symbiosis affects the plant photosynthetic capacity, particularly the efficiency of PSII. This study aimed at determining the influence of the AM symbiosis on the performance of PSII in rice plants subjected to salinity. Photosynthetic activity, plant gas-exchange parameters, accumulation of photosynthetic pigments and rubisco activity and gene expression were also measured in order to analyse comprehensively the response of the photosynthetic processes to AM symbiosis and salinity. Results showed that the AM symbiosis enhanced the actual quantum yield of PSII photochemistry and reduced the quantum yield of non-photochemical quenching in rice plants subjected to salinity. AM rice plants maintained higher net photosynthetic rate, stomatal conductance and transpiration rate than nonAM plants. Thus, we propose that AM rice plants had a higher photochemical efficiency for CO2 fixation and solar energy utilization and this increases plant salt tolerance by preventing the injury to the photosystems reaction centres and by allowing a better utilization of light energy in photochemical processes. All these processes translated into higher photosynthetic and rubisco activities in AM rice plants and improved plant biomass production under salinity. Copyright © 2015 Elsevier GmbH. All rights reserved.

  20. Conversion of fracture toughness testing values from small scale three point bending test specimens to small scale yielding state (SSY) by elastic-plastic stress analysis

    International Nuclear Information System (INIS)

    Ikonen, K.

    1993-07-01

    The report describes the work performed for achieving readiness to calculate fracture toughness dependence on dimension effects and loading conditions in fracture test specimens and real structures. In the report two- and three-dimensional computer codes developed and calculational methods applied are described. One of the main goals is to converse fracture toughness from small scale three point bending test specimens to case of a depth crack in plane strain i.e. to small scale yielding state (SSY) by numerical elastic-plastic stress analysis. Thickness effect of a test specimens and effect of a crack depth are separately investigated. Tests of three point bending specimens with and without sidegrooves and curved crack front are numerically simulated and experimental and computed results are compared. J-integral is calculated along crack front and also from force-deflection dependence of the beam. For the analyses the computing system was thoroughly automatized. Measuring capacity of three point bending test specimens was tried to evaluate. (orig.) (7 refs., 54 figs.)

  1. Stope Stability Assessment and Effect of Horizontal to Vertical Stress Ratio on the Yielding and Relaxation Zones Around Underground Open Stopes Using Empirical and Finite Element Methods

    Science.gov (United States)

    Sepehri, Mohammadali; Apel, Derek; Liu, Wei

    2017-09-01

    Predicting the stability of open stopes can be a challenging task for underground mine engineers. For decades, the stability graph method has been used as the first step of open stope design around the world. However, there are some shortcomings with this method. For instance, the stability graph method does not account for the relaxation zones around the stopes. Another limitation of the stability graph is that this method cannot to be used to evaluate the stability of the stopes with high walls made of backfill materials. However, there are several analytical and numerical methods that can be used to overcome these limitations. In this study, both empirical and numerical methods have been used to assess the stability of an open stope located between mine levels N9225 and N9250 at Diavik diamond underground mine. It was shown that the numerical methods can be used as complementary methods along with other analytical and empirical methods to assess the stability of open stopes. A three dimensional elastoplastic finite element model was constructed using Abaqus software. In this paper a sensitivity analysis was performed to investigate the impact of the stress ratio "k" on the extent of the yielding and relaxation zones around the hangingwall and footwall of the understudy stope.

  2. Evaluation of Drought Stress Effect on Growth, Essential Oil Percentage and Essential Oil Yield of Chamomile (Matricaria recutita L. Presov cultivar and Chicory (Cichorium intybus L. local cultivar in the North of Khuzestan

    Directory of Open Access Journals (Sweden)

    roozbeh farhoudi

    2017-10-01

    Full Text Available Introduction: Iran’s climate is mostly arid and semi-arid, where water availability is a major problem. Water stress substantially alters plant metabolism, decreasing plant growth and photosynthesis and profoundly affecting ecosystems and agriculture, as well as human societies. Unfortunately, water deficiency is increasingly becoming a serious problem in agriculture in Iran whereas the national average annual precipitation is less than 249 mm. Recently, medicinal and aromatic plants have received much attention in several fields such as agroalimentary, perfumes, pharmaceutical industries and natural cosmetic products. Although, secondary metabolites in the medicinal and aromatic plants impressed conventionally by their genetic makeup; moreover their biosynthesis is strongly influenced by environmental factors. It means biotic and abiotic environmental factors affect growth parameter, essential oil yield and constituents. Abiotic environmental stresses like drought have the most effect on medicinal plants. In arid and semi-arid regions like south of Iran where water availability is a major limitation, using plants with low water consumption is one way to manage available water efficiently. Chamomile (Matricaria recutita L. and chicory (Cichorium intybus are annual plants belonging to Asteraceae family naturally widespread in west, northwest and south of Iran and their consumption has a long history in Iranian folklore medicine. Over 120 components have been identified in these plants essential oil, while, chamazulene, camphor, bisabolol oxides A and B, farnesene and ά- bisabolonoxide are the most important ones. Materials and Methods: This study was conducted in Research Farm of Islamic Azad University, Shoshtar Branch, Iran during 2010-2011 in order to evaluate the effects of water stress levels on growth, photosynthesis and essential oil yield of German chamomile (Matricaria recutita L. and chicory (Cichorium intybus. Two water stress

  3. Stress

    Science.gov (United States)

    ... taking care of an aging parent. With mental stress, the body pumps out hormones to no avail. Neither fighting ... with type 1 diabetes. This difference makes sense. Stress blocks the body from releasing insulin in people with type 2 ...

  4. Understanding the weather signal in national crop-yield variability

    Science.gov (United States)

    Frieler, Katja; Schauberger, Bernhard; Arneth, Almut; Balkovič, Juraj; Chryssanthacopoulos, James; Deryng, Delphine; Elliott, Joshua; Folberth, Christian; Khabarov, Nikolay; Müller, Christoph; Olin, Stefan; Pugh, Thomas A. M.; Schaphoff, Sibyll; Schewe, Jacob; Schmid, Erwin; Warszawski, Lila; Levermann, Anders

    2017-06-01

    Year-to-year variations in crop yields can have major impacts on the livelihoods of subsistence farmers and may trigger significant global price fluctuations, with severe consequences for people in developing countries. Fluctuations can be induced by weather conditions, management decisions, weeds, diseases, and pests. Although an explicit quantification and deeper understanding of weather-induced crop-yield variability is essential for adaptation strategies, so far it has only been addressed by empirical models. Here, we provide conservative estimates of the fraction of reported national yield variabilities that can be attributed to weather by state-of-the-art, process-based crop model simulations. We find that observed weather variations can explain more than 50% of the variability in wheat yields in Australia, Canada, Spain, Hungary, and Romania. For maize, weather sensitivities exceed 50% in seven countries, including the United States. The explained variance exceeds 50% for rice in Japan and South Korea and for soy in Argentina. Avoiding water stress by simulating yields assuming full irrigation shows that water limitation is a major driver of the observed variations in most of these countries. Identifying the mechanisms leading to crop-yield fluctuations is not only fundamental for dampening fluctuations, but is also important in the context of the debate on the attribution of loss and damage to climate change. Since process-based crop models not only account for weather influences on crop yields, but also provide options to represent human-management measures, they could become essential tools for differentiating these drivers, and for exploring options to reduce future yield fluctuations.

  5. ATRF Earns Three Green Globes, Exceeds NIH Building Standards | Poster

    Science.gov (United States)

    By Ashley DeVine, Staff Writer From project management and energy and water efficiency to emissions and the indoor environment, the Advanced Technology Research Facility (ATRF) was built with sustainability in mind, exceeding the National Institutes of Health’s (NIH’s) building standards and earning three Green Globes from the Green Building Initiative (GBI).

  6. Estimating the exceedance probability of rain rate by logistic regression

    Science.gov (United States)

    Chiu, Long S.; Kedem, Benjamin

    1990-01-01

    Recent studies have shown that the fraction of an area with rain intensity above a fixed threshold is highly correlated with the area-averaged rain rate. To estimate the fractional rainy area, a logistic regression model, which estimates the conditional probability that rain rate over an area exceeds a fixed threshold given the values of related covariates, is developed. The problem of dependency in the data in the estimation procedure is bypassed by the method of partial likelihood. Analyses of simulated scanning multichannel microwave radiometer and observed electrically scanning microwave radiometer data during the Global Atlantic Tropical Experiment period show that the use of logistic regression in pixel classification is superior to multiple regression in predicting whether rain rate at each pixel exceeds a given threshold, even in the presence of noisy data. The potential of the logistic regression technique in satellite rain rate estimation is discussed.

  7. 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....

  8. 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.

  9. Effects of buffering mineral mixtures on milk yield, milk composition, rumen pH and some blood biochemical parameters in heat stressed dairy cows

    Directory of Open Access Journals (Sweden)

    Adamović Milan

    2014-01-01

    Full Text Available The objective of the work was to investigate the influence of partial substitution of magnesium oxide with natural bentonite in feed mixtures used in feeding of cows during their exposure to heat stress. The investigation lasted 30 days and was carried out during last ten days of may and first twenty days of June when average air temperature in stables was 36.6±2.5oC. In the experiment there were included 30 cows of Holstein breed in first phase of lactation, which were divided into two groups of 15 cows: control (C and experimental (E. Group C was fed with experimental mineral mixture that contained 60% of magnesium oxide during the whole investigation period. Group E was fed with experimental mineral mixture that contained 40% of magnesium oxide as well as 20% of natural bentonite. Remaining ingredients in both control and experimental mineral mixtures were the same and also contained 20% of sodium bicarbonate and 20% of zeolite in the same quantities. The control and experimental mineral mixtures were mixed into complete feed mixture (18% UP in the amount of 1%. At tne end of the investigation period, on the 30th day, there were taken samples of rumens contents for determining pH, and after that blood samples, in which, after the separation of blood serum, were determined glucose concentration, total proteins, albumin, globulin, urea, HDL cholesterol, LDL cholesterol, total bilirubin, calcium and phosphorus, as well as the activity of ALT and AST. By computation there was calculated the ratio between albumin and globulin, ALT and AST, and the ratio between calcium and phosphorus. Daily allowance and milk chemical composition ( percentage of fat, proteins and dry substance were determined at the end of the investigation period, that is on the 30th day of lactation, for each cow individually. Partial substitution of magnesium oxide with bentonite influenced milk production increase, but it was statistically insignificant. Besides that, in E

  10. Large deviation estimates for exceedance times of perpetuity sequences and their dual processes

    DEFF Research Database (Denmark)

    Buraczewski, Dariusz; Collamore, Jeffrey F.; Damek, Ewa

    2016-01-01

    In a variety of problems in pure and applied probability, it is of relevant to study the large exceedance probabilities of the perpetuity sequence $Y_n := B_1 + A_1 B_2 + \\cdots + (A_1 \\cdots A_{n-1}) B_n$, where $(A_i,B_i) \\subset (0,\\infty) \\times \\reals$. Estimates for the stationary tail dist......-time exceedance probabilities of $\\{ M_n^\\ast \\}$, yielding a new result concerning the convergence of $\\{ M_n^\\ast \\}$ to its stationary distribution.......In a variety of problems in pure and applied probability, it is of relevant to study the large exceedance probabilities of the perpetuity sequence $Y_n := B_1 + A_1 B_2 + \\cdots + (A_1 \\cdots A_{n-1}) B_n$, where $(A_i,B_i) \\subset (0,\\infty) \\times \\reals$. Estimates for the stationary tail...... distribution of $\\{ Y_n \\}$ have been developed in the seminal papers of Kesten (1973) and Goldie (1991). Specifically, it is well-known that if $M := \\sup_n Y_n$, then ${\\mathbb P} \\left\\{ M > u \\right\\} \\sim {\\cal C}_M u^{-\\xi}$ as $u \\to \\infty$. While much attention has been focused on extending...

  11. Derivation and Mapping of Critical Loads for Nitrogen and Trends in Their Exceedance in Germany

    Directory of Open Access Journals (Sweden)

    Hans-Dieter Nagel

    2001-01-01

    Full Text Available The term “critical load” means a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur, according to present knowledge. In the case of nitrogen, both oxidised and reduced compounds contribute to the total deposition of acidity, which exceeds critical loads in many forest ecosystems. These also cause negative effects through eutrophication. Critical loads of nitrogen were derived for forest soils (deciduous and coniferous forest, natural grassland, acid fens, heathland, and mesotrophic peat bogs. In Germany, a decrease in sulphur emissions over the past 15 years resulted in a reduced exceedance of critical loads for acid deposition. In the same period it was noted that reduction in the emissions of nitrogen oxides and ammonia remained insignificant. Therefore, emissions of nitrogen compounds have become relatively more important and will continue to threaten ecosystem function and stability. The risk of environmental damage remains at an unacceptable level. The German maps show the degree to which the critical loads are exceeded, and they present current developments and an expected future trend. Results indicate that recovery from pollutant stress occurs only gradually.

  12. Stress !!!

    NARCIS (Netherlands)

    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.

  13. Ridge and furrow systems with film cover increase maize yields and mitigate climate risks of cold and drought stress in continental climates

    NARCIS (Netherlands)

    Dong, Wanlin; Zhang, Lizhen; Duan, Yu; Sun, Li; Zhao, Peiyi; Werf, van der Wopke; Evers, Jochem B.; Wang, Qi; Wang, Ruonan; Sun, Zhigang

    2017-01-01

    Ridge-furrow tillage and plastic film cover are widely applied in China to mitigate climate risks, e.g. cool temperature and low rainfall. This study aimed to quantify the effects of ridge-furrow tillage and film cover on maize growth and yield in an environment with frequent seasonal drought and

  14. Yielding and flow of sheared colloidal glasses

    International Nuclear Information System (INIS)

    Petekidis, G; Vlassopoulos, D; Pusey, P N

    2004-01-01

    We have studied some of the rheological properties of suspensions of hard-sphere colloids with particular reference to behaviour near the concentration of the glass transition. First we monitored the strain on the samples during and after a transient step stress. We find that, at all values of applied step stress, colloidal glasses show a rapid, apparently elastic, recovery of strain after the stress is removed. This recovery is found even in samples which have flowed significantly during stressing. We attribute this behaviour to 'cage elasticity', the recovery of the stress-induced distorted environment of any particle to a more isotropic state when the stress is removed. Second, we monitored the stress as the strain rate dot γ of flowing samples was slowly decreased. Suspensions which are glassy at rest show a stress which becomes independent of dot γ as dot γ →0. This limiting stress can be interpreted as the yield stress of the glass and agrees well both with the yield stress deduced from the step stress and recovery measurements and that predicted by a recent mode coupling theory of sheared suspensions. Thus, the behaviours under steady shearing and transient step stress both support the idea that colloidal glasses have a finite yield stress. We note however that the samples do exhibit a slow accumulation of strain due to creep at stresses below the yield stress

  15. Indices of heart rate variability as potential early markers of metabolic stress and compromised regulatory capacity in dried-off high-yielding dairy cows.

    Science.gov (United States)

    Erdmann, S; Mohr, E; Derno, M; Tuchscherer, A; Schäff, C; Börner, S; Kautzsch, U; Kuhla, B; Hammon, H M; Röntgen, M

    2017-10-25

    High performing dairy cows experience distinct metabolic stress during periods of negative energy balance. Subclinical disorders of the cow's energy metabolism facilitate failure of adaptational responses resulting in health problems and reduced performance. The autonomic nervous system (ANS) with its sympathetic and parasympathetic branches plays a predominant role in adaption to inadequate energy and/or fuel availability and mediation of the stress response. Therefore, we hypothesize that indices of heart rate variability (HRV) that reflect ANS activity and sympatho-vagal balance could be early markers of metabolic stress, and possibly useful to predict cows with compromised regulatory capacity. In this study we analysed the autonomic regulation and stress level of 10 pregnant dried-off German Holstein cows before, during and after a 10-h fasting period by using a wide range of HRV parameters. In addition heat production (HP), energy balance, feed intake, rumen fermentative activity, physical activity, non-esterified fatty acids, β-hydroxybutyric acid, cortisol and total ghrelin plasma concentrations, and body temperature (BT) were measured. In all cows fasting induced immediate regulatory adjustments including increased lipolysis (84%) and total ghrelin levels (179%), reduction of HP (-16%), standing time (-38%) and heart rate (-15%). However, by analysing frequency domain parameters of HRV (high-frequency (HF) and low-frequency (LF) components, ratio LF/HF) cows could be retrospectively assigned to groups reacting to food removal with increased or decreased activity of the parasympathetic branch of the ANS. Regression analysis reveals that under control conditions (feeding ad libitum) group differences were best predicted by the nonlinear domain HRV component Maxline (L MAX, R 2=0.76, threshold; TS=258). Compared with cows having L MAX values above TS (>L MAX: 348±17), those with L MAX values below TS (fasting with a shift of their sympatho-vagal balance

  16. White dwarf stars exceeding the Chandrasekhar mass limit

    Science.gov (United States)

    Tomaschitz, Roman

    2018-01-01

    The effect of nonlinear ultra-relativistic electron dispersion on the mass-radius relation of high-mass white dwarfs is studied. The dispersion is described by a permeability tensor in the Dirac equation, generated by the ionized high-density stellar matter, which constitutes the neutralizing background of the nearly degenerate electron plasma. The electron dispersion results in a stable mass-radius relation for high-mass white dwarfs, in contrast to a mass limit in the case of vacuum permeabilities. In the ultra-relativistic regime, the dispersion relation is a power law whose amplitude and scaling exponent is inferred from mass and radius estimates of two high-mass white dwarfs, Sirius B and LHS 4033. Evidence for the existence of super-Chandrasekhar mass white dwarfs is provided by several Type Ia supernovae (e.g., SN 2013cv, SN 2003fg, SN 2007if and SN 2009dc), whose mass ejecta exceed the Chandrasekhar limit by up to a factor of two. The dispersive mass-radius relation is used to estimate the radii, central densities, Fermi temperatures, bulk and compression moduli and sound velocities of their white dwarf progenitors.

  17. Modeling environmental noise exceedances using non-homogeneous Poisson processes.

    Science.gov (United States)

    Guarnaccia, Claudio; Quartieri, Joseph; Barrios, Juan M; Rodrigues, Eliane R

    2014-10-01

    In this work a non-homogeneous Poisson model is considered to study noise exposure. The Poisson process, counting the number of times that a sound level surpasses a threshold, is used to estimate the probability that a population is exposed to high levels of noise a certain number of times in a given time interval. The rate function of the Poisson process is assumed to be of a Weibull type. The presented model is applied to community noise data from Messina, Sicily (Italy). Four sets of data are used to estimate the parameters involved in the model. After the estimation and tuning are made, a way of estimating the probability that an environmental noise threshold is exceeded a certain number of times in a given time interval is presented. This estimation can be very useful in the study of noise exposure of a population and also to predict, given the current behavior of the data, the probability of occurrence of high levels of noise in the near future. One of the most important features of the model is that it implicitly takes into account different noise sources, which need to be treated separately when using usual models.

  18. Delivered volumes of enteral nutrition exceed prescribed volumes.

    Science.gov (United States)

    Walker, Renee Nichole; Utech, Anne; Velez, Maria Eugenia; Schwartz, Katie

    2014-10-01

    Enteral nutrition (EN) provisions are typically calculated based on a 24-hour infusion period. However, feedings are often interrupted for daily activities, procedures, or gastrointestinal intolerance. The study's objective was to determine the delivered EN quantities provided to stable hospitalized patients, using cellular time and measured volumes to verify our EN calculation adjustment. A supply of consecutively numbered ready-to-hang (RTH) EN product was delivered to the bedside of 26 inpatients with established EN tolerance at goal rates on various types of nursing units. The dietitian weighed the volume remaining in the infusing product and recorded the measurement time. On the following days, the dietitian continued to weigh the infusing RTH product and the empty RTH bottles saved by nursing. The primary outcome was the difference between the prescribed and delivered EN provisions, which was calculated with a paired t test. Patients received significantly more calories in the delivered enteral feeding (mean [SD], 1678 [385] kcal) than prescribed calories in the EN order (1489 [246 kcal]; t = 3.736, P = .001), adjusting for observed time. No significant differences were found between nursing units, product, and rate. EN delivered may actually exceed ordered amounts by 5%–21% (mean, 12%) with feeding pump inaccuracy as the primary contributing factor. This differs from what others have found. Our findings support using a volume-based ordering system vs a rate-based ordering system for more accurate EN delivery.

  19. Amino acid production exceeds plant nitrogen demand in Siberian tundra

    Science.gov (United States)

    Wild, Birgit; Eloy Alves, Ricardo J.; Bárta, Jiři; Čapek, Petr; Gentsch, Norman; Guggenberger, Georg; Hugelius, Gustaf; Knoltsch, Anna; Kuhry, Peter; Lashchinskiy, Nikolay; Mikutta, Robert; Palmtag, Juri; Prommer, Judith; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Urich, Tim; Richter, Andreas

    2018-03-01

    Arctic plant productivity is often limited by low soil N availability. This has been attributed to slow breakdown of N-containing polymers in litter and soil organic matter (SOM) into smaller, available units, and to shallow plant rooting constrained by permafrost and high soil moisture. Using 15N pool dilution assays, we here quantified gross amino acid and ammonium production rates in 97 active layer samples from four sites across the Siberian Arctic. We found that amino acid production in organic layers alone exceeded literature-based estimates of maximum plant N uptake 17-fold and therefore reject the hypothesis that arctic plant N limitation results from slow SOM breakdown. High microbial N use efficiency in organic layers rather suggests strong competition of microorganisms and plants in the dominant rooting zone. Deeper horizons showed lower amino acid production rates per volume, but also lower microbial N use efficiency. Permafrost thaw together with soil drainage might facilitate deeper plant rooting and uptake of previously inaccessible subsoil N, and thereby promote plant productivity in arctic ecosystems. We conclude that changes in microbial decomposer activity, microbial N utilization and plant root density with soil depth interactively control N availability for plants in the Arctic.

  20. Experimental study on yield behavior of Daqing crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Lei [China University of Petroleum, College of Mechanical and Transportation Engineering, Beijing (China)

    2012-07-15

    The yield behavior of Daqing crude oil was studied by means of multi-mode controlled-stress tests with a high-precision stress controlled rheometer. Two experiments of creep and constant stress loading rate were performed. The yield stress of gelled crude oil was dependent on the test conditions such as the stress loading time and the stress loading rate, but the yield strain did not change with test conditions. The yield strain did exist objectively and it can be used as the criterion for the yielding of the structure of gelled crude oil. The yield strain of gelled oil was studied through experiments of creep, constant stress loading rate, oscillatory shear stress increase, and constant shear rate. The yield strain of gelled crude oil decreased with the increasing gel strength. The experiment of constant speed increase of stress showed the strain softening phenomena for low gel strength oil. (orig.)

  1. Combining field performance with controlled environment plant imaging to identify the genetic control of growth and transpiration underlying yield response to water-deficit stress in wheat.

    Science.gov (United States)

    Parent, Boris; Shahinnia, Fahimeh; Maphosa, Lance; Berger, Bettina; Rabie, Huwaida; Chalmers, Ken; Kovalchuk, Alex; Langridge, Peter; Fleury, Delphine

    2015-09-01

    Crop yield in low-rainfall environments is a complex trait under multigenic control that shows significant genotype×environment (G×E) interaction. One way to understand and track this trait is to link physiological studies to genetics by using imaging platforms to phenotype large segregating populations. A wheat population developed from parental lines contrasting in their mechanisms of yield maintenance under water deficit was studied in both an imaging platform and in the field. We combined phenotyping methods in a common analysis pipeline to estimate biomass and leaf area from images and then inferred growth and relative growth rate, transpiration, and water-use efficiency, and applied these to genetic analysis. From the 20 quantitative trait loci (QTLs) found for several traits in the platform, some showed strong effects, accounting for between 26 and 43% of the variation on chromosomes 1A and 1B, indicating that the G×E interaction could be reduced in a controlled environment and by using dynamic variables. Co-location of QTLs identified in the platform and in the field showed a possible common genetic basis at some loci. Co-located QTLs were found for average growth rate, leaf expansion rate, transpiration rate, and water-use efficiency from the platform with yield, spike number, grain weight, grain number, and harvest index in the field. These results demonstrated that imaging platforms are a suitable alternative to field-based screening and may be used to phenotype recombinant lines for positional cloning. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Changes in diurnal temperature range and national cereal yields

    Energy Technology Data Exchange (ETDEWEB)

    Lobell, D

    2007-04-26

    Models of yield responses to temperature change have often considered only changes in average temperature (Tavg), with the implicit assumption that changes in the diurnal temperature range (DTR) can safely be ignored. The goal of this study was to evaluate this assumption using a combination of historical datasets and climate model projections. Data on national crop yields for 1961-2002 in the 10 leading producers of wheat, rice, and maize were combined with datasets on climate and crop locations to evaluate the empirical relationships between Tavg, DTR, and crop yields. In several rice and maize growing regions, including the two major nations for each crop, there was a clear negative response of yields to increased DTR. This finding reflects a nonlinear response of yields to temperature, which likely results from greater water and heat stress during hot days. In many other cases, the effects of DTR were not statistically significant, in part because correlations of DTR with other climate variables and the relatively short length of the time series resulted in wide confidence intervals for the estimates. To evaluate whether future changes in DTR are relevant to crop impact assessments, yield responses to projected changes in Tavg and DTR by 2046-2065 from 11 climate models were estimated. The mean climate model projections indicated an increase in DTR in most seasons and locations where wheat is grown, mixed projections for maize, and a general decrease in DTR for rice. These mean projections were associated with wide ranges that included zero in nearly all cases. The estimated impacts of DTR changes on yields were generally small (<5% change in yields) relative to the consistently negative impact of projected warming of Tavg. However, DTR changes did significantly affect yield responses in several cases, such as in reducing US maize yields and increasing India rice yields. Because DTR projections tend to be positively correlated with Tavg, estimates of yields

  3. Stress.

    Science.gov (United States)

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself.

  4. Did European temperatures in 1540 exceed present-day records?

    Science.gov (United States)

    Orth, Rene; Vogel, Martha M.; Luterbacher, Jürg; Pfister, Christian; Seneviratne, Sonia I.

    2017-04-01

    There is strong evidence that the year 1540 was exceptionally dry and warm in Central Europe. Here we infer 1540 summer temperatures from the number of dry days (NDDs) in spring (March-May) and summer (June-August) in 1540 derived from historical documentary evidence published elsewhere, and compare our estimates with present-day temperatures. We translate the NDD values into temperature distributions using a linear relationship between modeled temperature and NDD from a 3000 year pre-industrial control simulation with the Community Earth System Model (CESM). Our results show medium confidence that summer mean temperatures (T JJA) and maximum temperatures (TXx) in Central Europe in 1540 were warmer than the respective present-day mean summer temperatures (assessed between 1966-2015). The model-based reconstruction suggests further that with a probability of 40%-70%, the highest daily temperatures in 1540 were even warmer than in 2003, while there is at most a 20% probability that the 1540 mean summer temperature was warmer than that of 2003 in Central Europe. As with other state-of-the-art analyses, the uncertainty of the reconstructed 1540 summer weather in this study is considerable, for instance as extrapolation is required because 1540-like events are not captured by the employed Earth system model (ESM), and neither by other ESMs. However, in addition to paleoclimatological approaches we introduce here an independent methodology to estimate 1540 temperatures, and contribute consequently to a reduced overall uncertainty in the analysis of this event. The characterization of such events and the related climate system functioning is particularly relevant in the context of global warming and the corresponding increase of extreme heat wave magnitude and occurrence frequency. Orth, R., M.M. Vogel, J. Luterbacher, C. Pfister, and S.I. Seneviratne, (2016): Did European temperatures in 1540 exceed present-day records? Env. Res. Lett., 11, 114021, doi: 10.1088/1748-9326/11/11/114021

  5. Normalized Rotational Multiple Yield Surface Framework (NRMYSF) stress-strain curve prediction method based on small strain triaxial test data on undisturbed Auckland residual clay soils

    Science.gov (United States)

    Noor, M. J. Md; Ibrahim, A.; Rahman, A. S. A.

    2018-04-01

    Small strain triaxial test measurement is considered to be significantly accurate compared to the external strain measurement using conventional method due to systematic errors normally associated with the test. Three submersible miniature linear variable differential transducer (LVDT) mounted on yokes which clamped directly onto the soil sample at equally 120° from the others. The device setup using 0.4 N resolution load cell and 16 bit AD converter was capable of consistently resolving displacement of less than 1µm and measuring axial strains ranging from less than 0.001% to 2.5%. Further analysis of small strain local measurement data was performed using new Normalized Multiple Yield Surface Framework (NRMYSF) method and compared with existing Rotational Multiple Yield Surface Framework (RMYSF) prediction method. The prediction of shear strength based on combined intrinsic curvilinear shear strength envelope using small strain triaxial test data confirmed the significant improvement and reliability of the measurement and analysis methods. Moreover, the NRMYSF method shows an excellent data prediction and significant improvement toward more reliable prediction of soil strength that can reduce the cost and time of experimental laboratory test.

  6. Boro e estresse hídrico na produção do girassol Boron and water stress on yield of sunflower

    Directory of Open Access Journals (Sweden)

    César de Castro

    2006-04-01

    Full Text Available Com este trabalho, objetivou-se estudar sob condições de casa-de-vegetação, o efeito da interação doses boro e estresse hídrico na produção de matéria seca total, produção de aquênios e conteúdo de óleo em girassol cultivado em Latossolo Vermelho Amarelo distrófico de textura média. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 4 x 4, com quatro repetições. Foram estudadas quatro doses de B: 0, 0,25, 0,5 e 2,0 mg kg-1, aplicado na forma de ácido bórico e quatro fases de controle de umidade: sem estresse hídrico durante o ciclo, com estresse hídrico durante o ciclo, estresse hídrico a partir do florescimento e estresse hídrico a partir do enchimento de aquênios. Os resultados mostraram que, independentemente da fase de aplicação ou não de estresse hídrico, a dose 0,5 mg dm-3 de B acarretou na maior produção de matéria seca total, produção de aquênios e rendimento de óleo por capítulo. A aplicação de estresse hídrico a partir do início do florescimento ou no enchimento de aqûenios acarreta em menor produção de matéria seca total, de aquênios e de óleo.The objective of this work was to study under greenhouse conditions, the effect of the interaction between boron rates and phases of water stress on total dry matter production, achene production, oil content and development of sunflower tillage in dystrophic Red Yellow Latosol of medium texture. The experimental design consisted of casual blocks, using factorial scheme 4x4, with four replicates. The treatments studied were: Four boron rates: 0, 0,25, 0,5 e 2,0 mg kg-1, applied through the boric acid form, and four period of soil water content: without water stress for the whole cycle, with water stress during the whole cycle, with stress after beginning of flowering and with water stress after beginning of grain filling. The results showed that independently of the presence or not of water stress, the 0,5 mg dm-3

  7. Yielding and shear banding in soft glassy materials

    NARCIS (Netherlands)

    Fall, A.; Paredes, J.; Bonn, D.

    2010-01-01

    Yield stress fluids have proven difficult to characterize, and a reproducible determination of the yield stress is difficult. We study two types of yield stress fluids (YSF) in a single system: simple and thixotropic ones. This allows us to show that simple YSF are simply a special case of

  8. Water splitting-biosynthetic system with CO₂ reduction efficiencies exceeding photosynthesis.

    Science.gov (United States)

    Liu, Chong; Colón, Brendan C; Ziesack, Marika; Silver, Pamela A; Nocera, Daniel G

    2016-06-03

    Artificial photosynthetic systems can store solar energy and chemically reduce CO2 We developed a hybrid water splitting-biosynthetic system based on a biocompatible Earth-abundant inorganic catalyst system to split water into molecular hydrogen and oxygen (H2 and O2) at low driving voltages. When grown in contact with these catalysts, Ralstonia eutropha consumed the produced H2 to synthesize biomass and fuels or chemical products from low CO2 concentration in the presence of O2 This scalable system has a CO2 reduction energy efficiency of ~50% when producing bacterial biomass and liquid fusel alcohols, scrubbing 180 grams of CO2 per kilowatt-hour of electricity. Coupling this hybrid device to existing photovoltaic systems would yield a CO2 reduction energy efficiency of ~10%, exceeding that of natural photosynthetic systems. Copyright © 2016, American Association for the Advancement of Science.

  9. Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods

    International Nuclear Information System (INIS)

    Hempel, Nico; Nitschke-Pagel, Thomas; Dilger, Klaus

    2017-01-01

    This research is dedicated to the experimental investigation of the residual stress relaxation in girth-welded pipes due to quasi-static bending loads. Ferritic-pearlitic steel pipes are welded with two passes, resulting in a characteristic residual stress state with high tensile residual stresses at the weld root. Also, four-point bending is applied to generate axial load stress causing changes in the residual stress state. These are determined both on the outer and inner surfaces of the pipes, as well as in the pipe wall, using X-ray and neutron diffraction. Focusing on the effect of tensile load stress, it is revealed that not only the tensile residual stresses are reduced due to exceeding the yield stress, but also the compressive residual stresses for equilibrium reasons. Furthermore, residual stress relaxation occurs both parallel and perpendicular to the applied load stress.

  10. High temperature (900-1300 C) mechanical behaviour of dendritic web grown silicon ribbons - Strain rate and temperature dependence of the yield stress

    Science.gov (United States)

    Mathews, V. K.; Gross, T. S.

    1987-01-01

    The mechanical behavior of dendritic web Si ribbons close the melting point was studied experimentally. The goal of the study was to generate data for modeling the generation of stresses and dislocation structures during growth of dendritic web Si ribbons, thereby permitting modifications to the production process, i.e., the temperature profile, to lower production costs for the photovoltaic ribbons. A laser was used to cut specimens in the direction of growth of sample ribbons, which were then subjected to tensile tests at temperatures up to 1300 C in an Ar atmosphere. The tensile strengths of the samples increased when the temperature rose above 1200 C, a phenomena which was attributed to the diffusion of oxygen atoms to the quasi-dislocation sites. The migration to the potential dislocations sites effectively locked the dislocations.

  11. Effect of the cold-rolling parameters and the yield strength of the strip material on the friction stresses in a deformation zone

    Science.gov (United States)

    Garber, E. A.; Yagudin, I. V.; Ermilov, V. V.; Traino, A. I.

    2009-10-01

    The reliability of the methods of determining the friction coefficient is analyzed, since the friction stresses in the deformation zone during cold rolling significantly affect the quality of cold-rolled sheets and the energy consumption. The well-known experimental data and empirical dependences are shown to contradict each other, and the statistical assurance of these dependences is absent. A database on the interrelated technological and energy-force parameters of a five-stand cold-rolling mill, which includes a wide range of steel grades and strip sizes and shapes, is analyzed. Regression analysis is used to obtain a statistically reliable regression dependence of the friction coefficient in the deformation zone on the most significant technological parameters. The application of this dependence decreases the error of energy-force calculations by more than two times.

  12. Atomistic simulations of the yielding of gold nanowires

    International Nuclear Information System (INIS)

    Diao Jiankuai; Gall, Ken; Dunn, Martin L.; Zimmerman, Jonathan A.

    2006-01-01

    We performed atomistic simulations to study the effect of free surfaces on the yielding of gold nanowires. Tensile surface stresses on the surfaces of the nanowires cause them to contract along the length with respect to the bulk face-centered cubic lattice and induce compressive stress in the interior. When the cross-sectional area of a nanowire is less than 2.45 nm x 2.45 nm, the wire yields under its surface stresses. Under external forces and surface stresses, nanowires yield via the nucleation and propagation of the {1 1 1} partial dislocations. The magnitudes of the tensile and compressive yield stress of nanowires increase and decrease, respectively, with a decrease of the wire width. The magnitude of the tensile yield stress is much larger than that of the compressive yield stress for small nanowires, while for small nanowires, tensile and compressive yield stresses have similar magnitudes. The critical resolved shear stress (RSS) by external forces depends on wire width, orientation and loading condition (tension vs. compression). However, the critical RSS in the interior of the nanowires, which is exerted by both the external force and the surface-stress-induced compressive stress, does not change significantly with wire width for same orientation and same loading condition, and can thus serve as a 'local' criterion. This local criterion is invoked to explain the observed size dependence of yield behavior and tensile/compressive yield stress asymmetry, considering surface stress effects and different slip systems active in tensile and compressive yielding

  13. Yield surface evolution for columnar ice

    Science.gov (United States)

    Zhou, Zhiwei; Ma, Wei; Zhang, Shujuan; Mu, Yanhu; Zhao, Shunpin; Li, Guoyu

    A series of triaxial compression tests, which has capable of measuring the volumetric strain of the sample, were conducted on columnar ice. A new testing approach of probing the experimental yield surface was performed from a single sample in order to investigate yield and hardening behaviors of the columnar ice under complex stress states. Based on the characteristic of the volumetric strain, a new method of defined the multiaxial yield strengths of the columnar ice is proposed. The experimental yield surface remains elliptical shape in the stress space of effective stress versus mean stress. The effect of temperature, loading rate and loading path in the initial yield surface and deformation properties of the columnar ice were also studied. Subsequent yield surfaces of the columnar ice have been explored by using uniaxial and hydrostatic paths. The evolution of the subsequent yield surface exhibits significant path-dependent characteristics. The multiaxial hardening law of the columnar ice was established experimentally. A phenomenological yield criterion was presented for multiaxial yield and hardening behaviors of the columnar ice. The comparisons between the theoretical and measured results indicate that this current model is capable of giving a reasonable prediction for the multiaxial yield and post-yield properties of the columnar ice subjected to different temperature, loading rate and path conditions.

  14. Exceeding Conventional Photovoltaic Efficiency Limits Using Colloidal Quantum Dots

    Science.gov (United States)

    Pach, Gregory F.

    details the synthesis of PbS/CdS heterostructures in which the PbS and CdS domains exist on opposite sides of the nanocrystal and are termed "Janus particles". Transient absorption spectroscopy shows MEG quantum yields above unity very the thermodynamic limit of 2Eg for PbS/CdS Janus particles. We further explain a mechanism for enhanced MEG using photoluminescence studies.

  15. Effect of sulfur and iron fertilizers on yield, yield components and ...

    African Journals Online (AJOL)

    Jane

    2011-06-13

    Jun 13, 2011 ... per plant. Interaction between water stress and combination of iron and sulfur fertilizers had significant .... Results of analysis of variance (ANOVA) of water stress (W), sulfur (B) and iron (C), and their interaction with gain yield, yield components and ... the soil structure and it increased the usefulness of other.

  16. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs

    Science.gov (United States)

    Brady, Gerald J.; Way, Austin J.; Safron, Nathaniel S.; Evensen, Harold T.; Gopalan, Padma; Arnold, Michael S.

    2016-01-01

    Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G0 = 4e2/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm−1, fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm−1, which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm−1 and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies. PMID:27617293

  17. Evaluation of a Biostimulant (Pepton Based in Enzymatic Hydrolyzed Animal Protein in Comparison to Seaweed Extracts on Root Development, Vegetative Growth, Flowering, and Yield of Gold Cherry Tomatoes Grown under Low Stress Ambient Field Conditions

    Directory of Open Access Journals (Sweden)

    Javier Polo

    2018-01-01

    effective improving yield of gold cherry tomatoes under the low stress ambient growing conditions of this experiment. Probably short-chain peptides present in Pepton are involved in endogenous hormones and metabolic mediators that could explain the results obtained in this study.

  18. Effect of Applied Stress and Temperature on Residual Stresses Induced by Peening Surface Treatments in Alloy 600

    Science.gov (United States)

    Telang, A.; Gnäupel-Herold, T.; Gill, A.; Vasudevan, V. K.

    2018-04-01

    In this study, the effects of applied tensile stress and temperature on laser shock peening (LSP) and cavitation shotless peening (CSP)-induced compressive residual stresses were investigated using neutron and x-ray diffraction. Residual stresses on the surface, measured in situ, were lower than the applied stress in LSP- and CSP-treated Alloy 600 samples (2 mm thick). The residual stress averaged over the volume was similar to the applied stress. Compressive residual stresses on the surface and balancing tensile stresses in the interior relax differently due to hardening induced by LSP. Ex situ residual stress measurements, using XRD, show that residual stresses relaxed as the applied stress exceeded the yield strength of the LSP- and CSP-treated Alloy 600. Compressive residual stresses induced by CSP and LSP decreased by 15-25% in magnitude, respectively, on exposure to 250-450 °C for more than 500 h with 10-11% of relaxation occurring in the first few hours. Further, 80% of the compressive residual stresses induced by LSP and CSP treatments in Alloy 600 were retained even after long-term aging at 350 °C for 2400 h.

  19. Particle debonding using different yield criteria

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Kuroda, Mitsutoshi

    2004-01-01

    Effects of plastic anisotropy in relation to debonding of rigid inclusions embedded in an elastic-viscoplastic metal are studied. Full finite strain analyses are carried out for plane cells assuming plane stress or plane strain. The overall stress strain response is calculated, when the cell......-matrix debonding. Keeping all material parameters fixed, the material response of the plane strain cell is considerably affected, due to debonding at a much reduced overall plastic strain compared to the corresponding plane stress cell. (C) 2004 Elsevier SAS. All rights reserved....... extent and shape of the particular yield function considered. The required overall straining of the cell for debonding initiation is related to the extent of the yield surfaces, since a high yield stress promotes debonding. Additionally, the maximum overall stress level for the cell is lower for the Hill...

  20. PRODUCCIÓN Y CALIDAD DE FRUTA EN CULTIVARES DE FRESA (Fragaria sp. AFECTADOS POR ESTRÉS SALINO YIELD AND FRUIT QUALITY OF SALT-STRESSED STRAWBERRY CULTIVARS (Fragaria sp.

    Directory of Open Access Journals (Sweden)

    Fánor Casierra-Posada

    2006-12-01

    levels. This trial was carried out to investigate the relationship between NaCl-salt stress, fruit quality and yield on the strawberries cultivars ‘Sweet Carlie’ ‘Chandler’ and ‘Camarosa’ grown in pots filled with salinized soil in glasshouse. Five salt levels were compared (0, 20, 40, 60 and 80 mM NaCl which induced different electrical conductivity (EC levels (2,68; 6,08; 8,24; 9,98 y 12,62 dS.m-1 respectly. The different EC levels were obtained by adding NaCl progressively to the soil. Fruit yield and quality were negatively influenced by the tested treatments. Sugar content in fruits was influenced by the treatments. Total soluble solids and tritrable acidity in fruits grew as EC levels grew. While the accumulation of dry matter in the roots showed a proportional increase with the level of NaCl in the substrate, the fruits showed an opposite tendency. Although typical stress symptoms such as growth retardation and poor fruit yield were observed in the strawberry tested cultivars, ‘Sweet Charlie’ was less sensitive to the salinity.

  1. Microencapsulation of β-Carotene Based on Casein/Guar Gum Blend Using Zeta Potential-Yield Stress Phenomenon: an Approach to Enhance Photo-stability and Retention of Functionality.

    Science.gov (United States)

    Thakur, Deepika; Jain, Ashay; Ghoshal, Gargi; Shivhare, U S; Katare, O P

    2017-07-01

    β-Carotene, abundant majorly in carrot, pink guava yams, spinach, kale, sweet potato, and palm oil, is an important nutrient for human health due to its scavenging action upon reactive free radicals wherever produced in the body. Inclusion of liposoluble β-carotene in foods and food ingredients is a challenging aspect due to its labile nature and low absorption from natural sources. This fact has led to the application of encapsulation of β-carotene to improve stability and bioavailability. The present work was aimed to fabricate microcapsules (MCs) of β-carotene oily dispersion using the complex coacervation technique with casein (CA) and guar gum (GG) blend. The ratio of CA:GG was found to be 1:0.5 (w/v) when optimized on the basis of zeta potential-yield stress phenomenon. These possessed a higher percentage yield (71.34 ± 0.55%), lower particle size (176.47 ± 4.65 μm), higher encapsulation efficiency (65.95 ± 5.33%), and in general, a uniform surface morphology was observed with particles showing optimized release behavior. Prepared MCs manifested effective and controlled release (up to 98%) following zero-order kinetics which was adequately explained by the Korseymer-Peppas model. The stability of the freeze-dried MCs was established in simulated gastrointestinal fluids (SGF, SIF) for 8 h. Antioxidant activity of the MCs was studied and revealed the retention of the functional architecture of β-carotene in freeze-dried MCs. Minimal photolytic degradation upon encapsulation of β-carotene addressed the challenge regarding photo-stability of β-carotene as confirmed via mass spectroscopy.

  2. Effects of Cd2+ on chlorophyll content in flag and grain yield of wheats

    International Nuclear Information System (INIS)

    Zhu Zhiyong; Li Youjun; Liu Yingjie; Duan Youqiang; Li Qiang; Hao Yufen; Guo Jia

    2011-01-01

    A field experiment was conducted with wheat cultivars Luohan 6 and Yumai 18 to investigate the effects of Cd 2+ stress on chlorophyll contents in flag leaves, flag leave area, thousand kernel weight, kernel filling velocity and yield of wheat. Results indicated that, under low Cd 2+ stress (10 mg/kg), the average contents of chlorophyll a + b of Luohan 6 reduced by 1.6%, however, its average area of flag leave and yield increased by 3.8% and 1.6%, respectively. At the same time, the average content of chlorophyll a + b, area of flag leave yield of Yumai 18 reduced 8.0%, 9.6% and 5.4%. Under high Cd 2+ stress (100 mg/kg), the average contents of chlorophyll a + b, areas of flag leaves and yields of Luohan 6 and Yumai 18 reduced by 29.2% and 30.5%, 6.3% and 17.4%, 16.7% and 36.7%, respectively. The results demonstrated that Cd 2+ restrained synthesis and accumulation of chlorophyll and its components. This study even showed that within a range of Cd 2+ concentration could promote the growth of flag leaves, and it also had an equal positive effect on yield of wheat if the Cd 2+ concentration in grains were not out of limit. The growth of flag leave and yield of wheat would be limited when Cd 2+ concentration exceed that range. Overall, Yumai 18 bore more poison from Cd 2+ than Luohan 6. (authors)

  3. Residual-stress distributions near stainless steel butt weldments

    International Nuclear Information System (INIS)

    Elligson, W.A.; Shack, W.J.

    1978-01-01

    Concern for the integrity of stainless steel butt-weldments in boiling-water-reactor (BWR) piping systems has stimulated study of the conditions that cause stress corrosion cracking (SCC) in the heat-affected zones (HAZ) of the weldments. It is generally agreed that a high stress exceeding the initial yield strength is one of the essential elements for crack initiation. Since design procedures usually ensure that load stresses are below initial yield, the source of the high stresses necessary to produce SCC is thought to be the residual stresses due to welding. To examine the level of residual stresses in the weldments of interest, bulk residual stresses were measured on 100 mm (4-in.) and 254 mm (10-in.) diameter Schedule 80 piping weldments using strain relief techniques. Both laboratory welded specimens and field welded specimens from reactors in service were studied. Axial bulk residual stress distributions were obtained at 45 0 intervals around the circumference. At each azimuthal position, the residual stresses were measured at seven axial positions: on the weld centerline and 13, 20, and 25 mm on either side of the weld centerline on both the inside and outside surfaces

  4. Effect of prior machining deformation on the development of tensile residual stresses in weld-fabricated nuclear components

    International Nuclear Information System (INIS)

    Prevey, P.S.; Mason, P.W.; Hornbach, D.J.; Molkenthin, J.P.

    1996-01-01

    Austenitic alloy weldments in nuclear systems may be subject to stress-corrosion cracking (SCC) failure if the sum of residual and applied stresses exceeds a critical threshold. Residual stresses developed by prior machining and welding may either accelerate or retard SCC, depending on their magnitude and sign. A combined x-ray diffraction and mechanical procedure was used to determine the axial and hoop residual stress and yield strength distributions into the inside-diameter surface of a simulated Alloy 600 penetration J-welded into a reactor pressure vessel. The degree of cold working and the resulting yield strength increase caused by prior machining and weld shrinkage were calculated from the line-broadening distributions. Tensile residual stresses on the order of +700 MPa were observed in both the axial and the hoop directions at the inside-diameter surface in a narrow region adjacent to the weld heat-affected zone. Stresses exceeding the bulk yield strength were found to develop due to the combined effects of cold working of the surface layers during initial machining and subsequent weld shrinkage. The residual stress and cold work distributions produced by prior machining were found to influence strongly the final residual stress state developed after welding

  5. What could have caused pre-industrial biomass burning emissions to exceed current rates?

    Directory of Open Access Journals (Sweden)

    G. R. van der Werf

    2013-01-01

    Full Text Available Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO and its isotopic signature measured at South Pole station (SPO. Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the

  6. An experimental study of the influence of stress history on fault slip during injection of supercritical CO2

    Science.gov (United States)

    Cuss, Robert J.; Wiseall, Andrew C.; Tamayo-Mas, Elena; Harrington, Jon F.

    2018-04-01

    The injection of super-critical CO2 into a depleted reservoir will alter the pore pressure of the basin, which if sufficiently perturbed could result in fault slip. Therefore, knowledge of the acceptable pressure limits is required in order to maintain fault stability. A two-part laboratory study was conducted on fully saturated kaolinite fault gouge to investigate this issue. Previously, we showed that fault slip occurred once pore-pressure within the gouge was sufficient to overcome the normal stress acting on the fault. For kaolinite, this behaviour occurred at a pressure similar to the yield stress. The current study shows that following a slow-reduction in the maximum principal stress, as would be expected through changes in effective stress, the reactivation pressure shows a stress memory. Consequently, the pressure necessary to initiate fault slip is similar to that required at the maximum stress encountered. Therefore, fault slip is at least partially controlled by the previous maximum stress and not the current stress state. During the slow reduction in normal stress, the flow characteristics of the fault remain unchanged until pore-pressure exceeds shear stress and does not increase significantly until it exceeds normal stress. This results in fault slip, which slows the rate of flow increase as shear is an effective self-sealing mechanism. These observations lead to the conclusion that stress history is a vital parameter when considering fault stability.

  7. 6 Grain Yield

    African Journals Online (AJOL)

    create a favourable environment for rice ... developing lines adaptable to many ... have stable, not too short crop duration with ..... Analysis of variance of the effect of site and season on maturity, grain yield and plant ..... and yield components.

  8. 29 CFR 4.162 - Fringe benefits under contracts exceeding $2,500.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefits under contracts exceeding $2,500. 4.162... Compensation Standards § 4.162 Fringe benefits under contracts exceeding $2,500. (a) Pursuant to the statutory... contain a provision specifying the fringe benefits to be furnished the various classes of service...

  9. 40 CFR 1045.107 - What are the not-to-exceed emission standards?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What are the not-to-exceed emission... Emission Standards and Related Requirements § 1045.107 What are the not-to-exceed emission standards? Not...) For engines equipped with a catalyst, use NTE multipliers from the following table across the...

  10. Prediction in Partial Duration Series With Generalized Pareto-Distributed Exceedances

    DEFF Research Database (Denmark)

    Rosbjerg, Dan; Madsen, Henrik; Rasmussen, Peter Funder

    1992-01-01

    As a generalization of the common assumption of exponential distribution of the exceedances in Partial duration series the generalized Pareto distribution has been adopted. Estimators for the parameters are presented using estimation by both method of moments and probability-weighted moments......-weighted moments. Maintaining the generalized Pareto distribution as the parent exceedance distribution the T-year event is estimated assuming the exceedances to be exponentially distributed. For moderately long-tailed exceedance distributions and small to moderate sample sizes it is found, by comparing mean...... square errors of the T-year event estimators, that the exponential distribution is preferable to the correct generalized Pareto distribution despite the introduced model error and despite a possible rejection of the exponential hypothesis by a test of significance. For moderately short-tailed exceedance...

  11. Improving growth and yield of cowpea by foliar application of ...

    African Journals Online (AJOL)

    Water stress impaired cowpea plant growth and decreased ion percentage and chlorophyll and carbohydrate concentration in the shoot as well as yield and its quality. Foliar-applied chitosan, in particular 250 mg/l, increased plant growth, yield and its quality as well as physiological constituents in plant shoot under stressed ...

  12. Heritability and correlates of maize yield ( Zea mays L .) under ...

    African Journals Online (AJOL)

    Heritability and correlates of maize yield ( Zea mays L .) under varying drought conditions. ... Nigeria Agricultural Journal ... Correlation analysis revealed that days to 50% tasseling and silking under non-stress, ASI and leaf senescence under severe stress exhibited negative and significant correlations with grain yield.

  13. Bond yield curve construction

    Directory of Open Access Journals (Sweden)

    Kožul Nataša

    2014-01-01

    Full Text Available In the broadest sense, yield curve indicates the market's view of the evolution of interest rates over time. However, given that cost of borrowing it closely linked to creditworthiness (ability to repay, different yield curves will apply to different currencies, market sectors, or even individual issuers. As government borrowing is indicative of interest rate levels available to other market players in a particular country, and considering that bond issuance still remains the dominant form of sovereign debt, this paper describes yield curve construction using bonds. The relationship between zero-coupon yield, par yield and yield to maturity is given and their usage in determining curve discount factors is described. Their usage in deriving forward rates and pricing related derivative instruments is also discussed.

  14. Yield and competition in barley variety mixtures

    Directory of Open Access Journals (Sweden)

    Kari Jokinen

    1991-09-01

    Full Text Available Competition between spring barley varieties and yield performance of two-, three and four-variety mixtures were studied in two replacement series field experiments. In the first experiment, repeated in three successive years (1983 —85 the components were the six-row varieties Agneta, Arra, Hja-673 and Porno. In the second experiment (1984, including two nitrogen doses (50 and 100 kgN/ha, both six-row (Agneta, Pomo and two-row (Ida, Kustaa varieties were used. Arra in the first and Agneta in the second experiment were the most competitive varieties. The results suggested that the fast growth of Arra at the beginning promoted its competitive ability. Increase in available nitrogen usually strengthened the competitiveness of Agneta. The observed competitive differences between varieties were not related to the earliness of a variety, neither to the morphological characters (two- and six-row varieties nor to the grain yield of a variety grown alone. The competitive ability was not always a stable character, the dominant suppression relationship varying from one environment to another (e.g. growing season, nitrogen dose. The observed overyielding was not statistically significant. The ratio of actual to expected yield and the relative yield total of several mixtures exceeded slightly one. As a conclusion, the yield advantage of mixtures was marginal. As a rule, the mixtures were not more stable than monocultures as determined by the coefficient of variation. However, the yield of some mixtures varied less than the yield of the most stable monoculture.

  15. Measurements of fission yields

    International Nuclear Information System (INIS)

    Denschlag, H.O.

    2000-01-01

    After some historical introductory remarks on the discovery of nuclear fission and early fission yield determinations, the present status of knowledge on fission yields is briefly reviewed. Practical and fundamental reasons motivating the pursuit of fission yield measurements in the coming century are pointed out. Recent results and novel techniques are described that promise to provide new interesting insights into the fission process during the next century. (author)

  16. Prediction in Partial Duration Series With Generalized Pareto-Distributed Exceedances

    DEFF Research Database (Denmark)

    Rosbjerg, Dan; Madsen, Henrik; Rasmussen, Peter Funder

    1992-01-01

    As a generalization of the common assumption of exponential distribution of the exceedances in Partial duration series the generalized Pareto distribution has been adopted. Estimators for the parameters are presented using estimation by both method of moments and probability-weighted moments...... distributions (with physically justified upper limit) the correct exceedance distribution should be applied despite a possible acceptance of the exponential assumption by a test of significance....

  17. N-acetylcysteine increased rice yield

    OpenAIRE

    NOZULAIDI, MOHD; JAHAN, MD SARWAR; KHAIRI, MOHD; KHANDAKER, MOHAMMAD MONERUZZAMAN; NASHRIYAH, MAT; KHANIF, YUSOP MOHD

    2015-01-01

    N-acetylcysteine (NAC) biosynthesized reduced glutathione (GSH), which maintains redox homeostasis in plants under normal and stressful conditions. To justify the effects of NAC on rice production, we measured yield parameters, chlorophyll (Chl) content, minimum Chl fluorescence (Fo), maximum Chl fluorescence (Fm), quantum yield (Fv/Fm), net photosynthesis rate (Pn), photosynthetically active radiation (PAR), and relative water content (RWC). Four treatments, N1G0 (nitrogen (N) with no NAC), ...

  18. Fission product yields

    International Nuclear Information System (INIS)

    Valenta, V.; Hep, J.

    1978-01-01

    Data are summed up necessary for determining the yields of individual fission products from different fissionable nuclides. Fractional independent yields, cumulative and isobaric yields are presented here for the thermal fission of 235 U, 239 Pu, 241 Pu and for fast fission (approximately 1 MeV) of 235 U, 238 U, 239 Pu, 241 Pu; these values are included into the 5th version of the YIELDS library, supplementing the BIBFP library. A comparison is made of experimental data and possible improvements of calculational methods are suggested. (author)

  19. Yield, yield components and dry matter digestibility of alfalfa experimental populations

    Directory of Open Access Journals (Sweden)

    Katić Slobodan

    2010-01-01

    Full Text Available Alfalfa is the most important forage crop grown in the temperate regions. It is cultivated for production of vegetative aerial mass used fresh or as hay, and recently as haylage and silage. In many centres worldwide, efforts are made to breed and create new alfalfa cultivars with both higher yields and of higher nutritional value. The aim of this paper was to determine yield and digestibility of 12 experimental populations of alfalfa, and to compare their results to the yields of well-known domestic alfalfa commercial cultivars. The results show significant differences in yield of green forage and dry matter among alfalfa populations, as well as in yield components, height, proportion of leaves in yield and growth rate (tab. 1, 2 and 3. Differences between in vitro digestible dry matter (% and yields of in vitro digestible dry matter (t ha-1 were also significant (tab. 5 and 6. Yield and quality of experimental populations were at the same level or higher than of control cultivars. Synthetic SINUSA exceeded the control cutivars (NS Mediana ZMS V and Banat VS in yield and quality of dry matter. .

  20. Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou; Howell, Gary L.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... for structural integrity. The paper presents the results and the analyses of model tests with 200 kg and 200 g load-cell instrumented Dolosse. Static stresses and wave generated stresses were studied as well as model and scale effects. A preliminary design diagram for Dolosse is presented as well....

  1. Water limits to closing yield gaps

    Science.gov (United States)

    Davis, Kyle Frankel; Rulli, Maria Cristina; Garrassino, Francesco; Chiarelli, Davide; Seveso, Antonio; D'Odorico, Paolo

    2017-01-01

    Agricultural intensification is often seen as a suitable approach to meet the growing demand for agricultural products and improve food security. It typically entails the use of fertilizers, new cultivars, irrigation, and other modern technology. In regions of the world affected by seasonal or chronic water scarcity, yield gap closure is strongly dependent on irrigation (blue water). Global yield gap assessments have often ignored whether the water required to close the yield gap is locally available. Here we perform a gridded global analysis (10 km resolution) of the blue water consumption that is needed annually to close the yield gap worldwide and evaluate the associated pressure on renewable freshwater resources. We find that, to close the yield gap, human appropriation of freshwater resources for irrigation would have to increase at least by 146%. Most study countries would experience at least a doubling in blue water requirement, with 71% of the additional blue water being required by only four crops - maize, rice, soybeans, and wheat. Further, in some countries (e.g., Algeria, Morocco, Syria, Tunisia, and Yemen) the total volume of blue water required for yield gap closure would exceed sustainable levels of freshwater consumption (i.e., 40% of total renewable surface and groundwater resources).

  2. Clinical and psychosocial predictors of exceeding target length of stay during inpatient stroke rehabilitation.

    Science.gov (United States)

    Lai, Wesley; Buttineau, Mackenzie; Harvey, Jennifer K; Pucci, Rebecca A; Wong, Anna P M; Dell'Erario, Linda; Bosnyak, Stephanie; Reid, Shannon; Salbach, Nancy M

    2017-10-01

    In Ontario, Canada, patients admitted to inpatient rehabilitation hospitals post-stroke are classified into rehabilitation patient groups based on age and functional level. Clinical practice guidelines, called quality-based procedures, recommend a target length of stay (LOS) for each group. The study objective was to evaluate the extent to which patients post-stroke at an inpatient rehabilitation hospital are meeting LOS targets and to identify patient characteristics that predict exceeding target LOS. A quantitative, longitudinal study from an inpatient rehabilitation hospital was conducted. Participants included adult patients (≥18 years) with stroke, admitted to an inpatient rehabilitation hospital between 2014 and 2015. The percentage of patients exceeding the recommended target LOS was determined. Logistic regression was performed to identify clinical and psychosocial patient characteristics associated with exceeding target LOS after adjusting for stroke severity. Of 165 patients, 38.8% exceeded their target LOS. Presence of ataxia, recurrent stroke, living alone, absence of a caregiver at admission, and acquiring a caregiver during hospital LOS was each associated with significantly higher odds of exceeding target LOS in comparison to patients without these characteristics after adjusting for stroke severity (p stroke-specific factors may be helpful to adjust LOS expectations and promote efficient resource allocation. This exploratory study was limited to findings from one inpatient rehabilitation hospital. Cross-validation of results using data-sets from multiple rehabilitation hospitals across Ontario is recommended.

  3. Influence of overelastic loading on the stress intensity factor under thermal fatigue conditions

    International Nuclear Information System (INIS)

    Stamm, H.; Munz, D.

    1983-10-01

    Thermal shock loading often creates high thermal stresses which may exceed yield strength of the material in a surface layer. In this report the application of the linear elastic ΔK-concept in the case of cyclic thermal loading within the shakedown region is discussed. To this K-factors for an edge crack in a linear elastic - perfectly plastic plate are calculated using the weight function method and are compared with results obtained with the Finite Element Method. It is shown, that rearrangement stresses during plastic flow in the first cycle must be taken into account developing conservative approximation procedures. (orig.) [de

  4. Soviet test yields

    Science.gov (United States)

    Vergino, Eileen S.

    Soviet seismologists have published descriptions of 96 nuclear explosions conducted from 1961 through 1972 at the Semipalatinsk test site, in Kazakhstan, central Asia [Bocharov et al., 1989]. With the exception of releasing news about some of their peaceful nuclear explosions (PNEs) the Soviets have never before published such a body of information.To estimate the seismic yield of a nuclear explosion it is necessary to obtain a calibrated magnitude-yield relationship based on events with known yields and with a consistent set of seismic magnitudes. U.S. estimation of Soviet test yields has been done through application of relationships to the Soviet sites based on the U.S. experience at the Nevada Test Site (NTS), making some correction for differences due to attenuation and near-source coupling of seismic waves.

  5. Stress analysis of a rupture disk

    International Nuclear Information System (INIS)

    Werne, R.W.

    1975-04-01

    The results of an elastic stress analysis of the rupture disk for an internal pressure of 45.5 MPa (6600 psi) indicate that the maximum von Mises stresses occur in the membrane and are on the order of 483 to 690 MPa (70,000 psi). This far exceeds the yield of the membrane material of 207 MPa (30,000 psi). These high stresses are expected since the membrane is designed to burst at that design pressure. The von Mises stresses in the rest of the body are less than 138 MPa (20,000 psi). An elastic-plastic analysis of the membrane alone subjected to the 45.5 MPa (6600 psi) pressure indicates that it becomes plastically unstable, i.e., it continues to deform under constant load. A second load case with a constant 6.9 MPa (1000 psi) pressure throughout the entire body (i.e., after release of pressure by burst of the membrane) was analyzed. The results indicate that the elastic von Mises stresses are less than 26.7 MPa (3880 psi) throughout the body. (U.S.)

  6. What could have caused pre-industrial biomass burning emissions to exceed current rates?

    NARCIS (Netherlands)

    van der Werf, G. R.; Peters, W.; van Leeuwen, T. T.; Giglio, L.

    2012-01-01

    Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked

  7. Relating road salt to exceedances of the water quality standard for chloride in New Hampshire streams.

    Science.gov (United States)

    Trowbridge, Philip R; Kahl, J Steve; Sassan, Dari A; Heath, Douglas L; Walsh, Edward M

    2010-07-01

    Six watersheds in New Hampshire were studied to determine the effects of road salt on stream water quality. Specific conductance in streams was monitored every 15 min for one year using dataloggers. Chloride concentrations were calculated from specific conductance using empirical relationships. Stream chloride concentrations were directly correlated with development in the watersheds and were inversely related to streamflow. Exceedances of the EPA water quality standard for chloride were detected in the four watersheds with the most development. The number of exceedances during a year was linearly related to the annual average concentration of chloride. Exceedances of the water quality standard were not predicted for streams with annual average concentrations less than 102 mg L(-1). Chloride was imported into three of the watersheds at rates ranging from 45 to 98 Mg Cl km(-2) yr(-1). Ninety-one percent of the chloride imported was road salt for deicing roadways and parking lots. A simple, mass balance equation was shown to predict annual average chloride concentrations from streamflow and chloride import rates to the watershed. This equation, combined with the apparent threshold for exceedances of the water quality standard, can be used for screening-level TMDLs for road salt in impaired watersheds.

  8. How "ought" exceeds but implies "can": Description and encouragement in moral judgment.

    Science.gov (United States)

    Turri, John

    2017-11-01

    This paper tests a theory about the relationship between two important topics in moral philosophy and psychology. One topic is the function of normative language, specifically claims that one "ought" to do something. Do these claims function to describe moral responsibilities, encourage specific behavior, or both? The other topic is the relationship between saying that one "ought" to do something and one's ability to do it. In what respect, if any, does what one "ought" to do exceed what one "can" do? The theory tested here has two parts: (1) "ought" claims function to both describe responsibilities and encourage people to fulfill them (the dual-function hypothesis); (2) the two functions relate differently to ability, because the encouragement function is limited by the person's ability, but the descriptive function is not (the interaction hypothesis). If this theory is correct, then in one respect "ought implies can" is false because people have responsibilities that exceed their abilities. But in another respect "ought implies can" is legitimate because it is not worthwhile to encourage people to do things that exceed their ability. Results from two behavioral experiments support the theory that "ought" exceeds but implies "can." Results from a third experiment provide further evidence regarding an "ought" claim's primary function and how contextual features can affect the interpretation of its functions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. What could have caused pre-industrial biomass burning emissions to exceed current rates?

    NARCIS (Netherlands)

    Werf, van der G.R.; Peters, W.; Leeuwen, van T.T.; Giglio, L.

    2013-01-01

    Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked

  10. Mercury in United Kingdom topsoils; concentrations, pools, and Critical Limit exceedances

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E., E-mail: et@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Poskitt, J.M.; Lawlor, A.J.; Wadsworth, R.A. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Norris, D.A.; Hall, J.R. [Centre for Ecology and Hydrology, Bangor, Gwynedd LL57 2UW (United Kingdom)

    2011-12-15

    The median total mercury concentration in 898 UK rural topsoils, sampled between 1998 and 2008, was 0.095 {mu}g g{sup -1}. Approximate adjustment for unreactive metal produced an estimate of 0.052 {mu}g g{sup -1} for reactive Hg. The highest concentrations were in the north and west, where organic-rich soils with low bulk densities dominate, but the spatial pattern was quite different if soil Hg pools (mg m{sup -2}) were considered, the highest values being near to the industrial north of England and London. Possible toxic effects of Hg were best evaluated by comparison with soil Critical Limits expressed as ratios of Hg to soil organic matter, or soil solution Hg{sup 2+} concentrations, estimated by chemical speciation modelling. Only a few percent of the rural UK soils showed exceedance, and this also applied to rural soils from the whole of Europe. UK urban and industrial soils had higher Hg concentrations and more cases of exceedance. - Highlights: > Concentrations of Hg in rural soils are highest near to industrial areas and London. > Mercury is strongly associated with soil organic matter. > Only a few percent of UK rural soils have Hg levels higher than Critical Limits. > Critical Limit exceedances are found for 15-30% of urban and industrial soils. - Mercury contents of 898 UK and 868 European rural soils are largely lower than Critical Limit values, but appreciable numbers of soils in UK urban and industrial areas show exceedance.

  11. 40 CFR 141.208 - Special notice for exceedance of the SMCL for fluoride.

    Science.gov (United States)

    2010-07-01

    ... exceed 2 mg/l because of this cosmetic dental problem. For more information, please call [name of water system contact] of [name of community water system] at [phone number]. Some home water treatment units... drinking water provided by your community water system [name] has a fluoride concentration of [insert value...

  12. A Study on OBE Exceedance Criteria Using the CAV Concept for NPPs in Korea

    International Nuclear Information System (INIS)

    Park, Se Moon; Cho, Sung Il; Yun, Kwan Hee

    2009-01-01

    NPPs in Korea have so far complied with the US Regulatory Guide 1.12 Rev.1 (1974) for the seismic monitoring systems. However, researchers in Korea have been considering attempting to comply with Regulatory Guide 1.12 rev.2 (1997) when implementing all future seismic monitoring systems. To comply with the new regulations, Operating Basis Earthquake (OBE) Exceedance Criteria applied with the Cumulative Absolute Velocity (CAV) has to be developed for local use. The CAV was developed in the USA as one reasonable OBE exceedance criterion for NPPs; however, it has not been widely used outside the USA, not-withstanding its solid technical basis. It is, however, expected that the worldwide NPP construction boom will necessitate development and more frequent use of reasonable OBE exceedance criteria. As multi-units (four or more) are situated in one site in Korea, prevention of simultaneous shutdown of multi-unit caused by non damaging earthquakes is very important; otherwise, a serious economic loss could occur, and there could also be a great impact on the stability of the power grid that would arise due to the unnecessary shutdown. Actually, we have had the experience of observing a Peak Ground Acceleration (PGA)-value greater than 0.1g (the current OBE level for Korean NPPs) due to an M=4.8 earthquake (20 th Jan. '07) that did not even cause any damage to the poorly-designed structures nearby. This experience gave a motivation to the KHNP should concern the needs of study on OBE exceedance criteria in view of application of the CAV to Korean seismic situation, which will be more practical. The present paper is intended to show the intermediate result of the research on Operating Basis Earthquake (OBE) exceedance criteria in Korea

  13. Yield point of metallic glass

    International Nuclear Information System (INIS)

    Shimizu, Futoshi; Ogata, Shigenobu; Li, Ju

    2006-01-01

    Shear bands form in most bulk metallic glasses (BMGs) within a narrow range of uniaxial strain ε y ≅ 2%. We propose this critical condition corresponds to embryonic shear band (ESB) propagation, not its nucleation. To propagate an ESB, the far-field shear stress τ ∞ ∼ Eε y /2 must exceed the quasi-steady-state glue traction τ glue of shear-alienated glass until the glass transition temperature is approached internally due to frictional heating, at which point ESB matures as a runaway shear crack. The incubation length scale l inc necessary for this maturation is estimated to be ∼10 2 nm for Zr-based BMGs, below which sample size-scale shear localization does not happen. In shear-alienated glass, the last resistance against localized shearing comes from extremely fast downhill dissipative dynamics of timescale comparable to atomic vibrations, allowing molecular dynamics (MD) simulations to capture this recovery process which governs τ glue . We model four metallic glasses: a binary Lennard-Jones system, two binary embedded atom potential systems and a quinternary embedded atom system. Despite vast differences in the structure and interatomic interactions, the four MD calculations give ε y predictions of 2.4%, 2.1%, 2.6% and 2.9%, respectively

  14. Efficient Return Algorithms For Associated Plasticity With Multiple Yield Planes

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars

    2006-01-01

    of such criteria. The return formulae are in closed form and no iteration is required. The method accounts for three types of stress return: Return to a single yield plane, to a discontinuity line at the intersection of two yield planes and to a discontinuity point at the intersection between three or more yield...... planes. The infinitesimal and the consistent elastoplastic constitutive matrix are calculated for each type of stress return, as are the conditions to ascertain which type of return is required. The method is exemplified with the Mohr-Coulomb yield criterion....

  15. Enhancement of HHG yield

    International Nuclear Information System (INIS)

    Serrat, C.; Biegert, J.

    2011-01-01

    A static electric field periodically distributed in space controls and enhances the yield in high harmonic generation. The method is relatively simple to implement and allows tuning from the extreme-ultraviolet to soft X-ray. The radiation yield is selectively enhanced due to symmetry breaking induced by a static electric field on the interaction between the driving laser and the medium. The enhanced spectral region is tuned by varying the periodicity of the static electric field. Simulations predict an increase of more than two orders of magnitude for harmonics in the water window spectral range.

  16. Observed ozone exceedances in Italy: statistical analysis and modelling in the period 2002-2015

    Science.gov (United States)

    Falasca, Serena; Curci, Gabriele; Candeloro, Luca; Conte, Annamaria; Ippoliti, Carla

    2017-04-01

    Local ambient air quality is strongly influenced by anthropogenic emissions and meteorological conditions. The year 2015 is considered by NASA scientists as one of the hottest at the global scale since 1880. Furthermore, in Europe it was the first summer after the introduction of Euro6 regulation, the latest emission standard for passenger vehicles. The goal of this study is twofold: (1) the investigation of the impact of the heat wave occurred in the summer of 2015 on ozone levels and (2) the exploration of the weight of temperature as driver of high-level ozone events with respect to other variables. We performed a quantitative examination of the ozone seasons (May-September) for the period 2002-2015 using ozone concentration and weather data from 24 stations across Italy. The number of exceedances of limit values set by the European directive was calculated for each year, and compared with the trend of ozone concentration and temperature. Furthermore, the data were grouped in clusters of consecutive days of ozone exceedances in order to characterize the duration and the intensity of high ozone events. Finally, we developed a multivariate logistic regression model to investigate the role of a set of independent variables (meteorological, and temporal variables, altitude, number of inhabitants, vehicle emission standard) on the probability of exceedances. Results show that 2015 is one of the hottest years after 2003. During the period 2002-2015, the average number of exceedances per station of the daily maximum 8-hour average is often higher than the limit established by the European directive (25 per year). The highest number of exceedances was 65 per station, reached in 2003. The Po Valley is confirmed as a hot spot for pollution, with more frequent exceedances and a higher sensitivity to temperature, especially at urban sites. Ozone events in 2015 were fewer than recent years, but of longer duration (on average 4 days against 3 days), and with similar mean

  17. Forage yield and nutritive value of Panicum maximum genotypes in the Brazilian savannah

    Directory of Open Access Journals (Sweden)

    Francisco Duarte Fernandes

    2014-02-01

    Full Text Available The narrow genetic variability of grasslands and the incidence of new biotic and abiotic stresses have motivated the selection of new Panicum maximum genotypes for use as forage for beef cattle in the Brazilian savannah. This study aimed to evaluate forage yield and nutritive value of P. maximum genotypes including 14 accessions (PM30 to PM43, four intraspecific hybrids (PM44 to PM47 and six cultivars (Aruana, Massai, Milênio, Mombaça, Tanzania and Vencedor, examining 24 genotypes over two years (2003 and 2004. Milênio cultivar was the genotype with the highest dry matter yield (DMY in both years (18.4 t ha-1 and 20.9 t ha-1, respectively although it presented a high proportion of stems (~ 30%. Genotypes that showed higher Leaf DMY in both years were the accession PM34 (14.7 t ha-1 and the hybrid PM46 (14.0 t ha-1, while Mombaça and Tanzania yielded 12.5 and 11.0 t ha-1, respectively. Leaf organic matter digestibility and leaf DMY for PM40 and PM46 genotypes exceeded the mean (> 656 g kg-1 and > 11.7 t ha-1, respectively. For this reason, PM40 and PM46 can be considered promising P. maximum genotypes for use as forage for grazing systems in the Brazilian savannah.

  18. An experimental study on developing seismic damage indicator appearing OBE exceedance

    International Nuclear Information System (INIS)

    Park, D. S.; Kwon, K. J.; Lee, J. L.

    2000-01-01

    Immediate measurement should be taken depending on the level of seismic damage to nuclear power plants when an earthquake exceeds Operating Base Earthquake by NRC regulatory guide. An earthquake at nuclear plant site is felt with seismic instrument and analyzed by seismic monitoring systems. However, if operators of insufficient knowledge to earthquake can recognize the intensity of the earthquake with a subsidiary indicating model, more immediate response can be conducted. This subsidiary indicating model is called seismic damage indicator. In this regard, an experimental study using shaking table was conducted to develop the seismic damage indicator by CAV and OBE compatible with NRC standard response spectrum. In this test result, stacked acrylic cylinders were manufactured to behave consistently for each direction of seismic load. If the developed SDI is installed in nuclear power plants, it is seemed to be useful in easily determining OBE exceedance easily, and counteracting by plant operator along with the existing seismic monitoring systems

  19. 41 CFR 102-85.105 - How does an agency pay for customer alterations that exceed the TI allowance?

    Science.gov (United States)

    2010-07-01

    ... for customer alterations that exceed the TI allowance? 102-85.105 Section 102-85.105 Public Contracts....105 How does an agency pay for customer alterations that exceed the TI allowance? Amounts exceeding the TI allowance are paid in a one-time lump sum and are not amortized over the term of the occupancy...

  20. Development of Thresholds and Exceedance Probabilities for Influent Water Quality to Meet Drinking Water Regulations

    Science.gov (United States)

    Reeves, K. L.; Samson, C.; Summers, R. S.; Balaji, R.

    2017-12-01

    Drinking water treatment utilities (DWTU) are tasked with the challenge of meeting disinfection and disinfection byproduct (DBP) regulations to provide safe, reliable drinking water under changing climate and land surface characteristics. DBPs form in drinking water when disinfectants, commonly chlorine, react with organic matter as measured by total organic carbon (TOC), and physical removal of pathogen microorganisms are achieved by filtration and monitored by turbidity removal. Turbidity and TOC in influent waters to DWTUs are expected to increase due to variable climate and more frequent fires and droughts. Traditional methods for forecasting turbidity and TOC require catchment specific data (i.e. streamflow) and have difficulties predicting them under non-stationary climate. A modelling framework was developed to assist DWTUs with assessing their risk for future compliance with disinfection and DBP regulations under changing climate. A local polynomial method was developed to predict surface water TOC using climate data collected from NOAA, Normalized Difference Vegetation Index (NDVI) data from the IRI Data Library, and historical TOC data from three DWTUs in diverse geographic locations. Characteristics from the DWTUs were used in the EPA Water Treatment Plant model to determine thresholds for influent TOC that resulted in DBP concentrations within compliance. Lastly, extreme value theory was used to predict probabilities of threshold exceedances under the current climate. Results from the utilities were used to produce a generalized TOC threshold approach that only requires water temperature and bromide concentration. The threshold exceedance model will be used to estimate probabilities of exceedances under projected climate scenarios. Initial results show that TOC can be forecasted using widely available data via statistical methods, where temperature, precipitation, Palmer Drought Severity Index, and NDVI with various lags were shown to be important

  1. Impact analysis of TOTEM data at the LHC: black disk limit exceeded

    CERN Document Server

    Alkin, A; Kovalenko, O; Troshin, S M

    2015-01-01

    We discuss the profile of the impact--parameter dependent elastic scattering amplitude. Extraction of impact-parameter dependence from the dataset with inclusion of the experimental data on elastic scattering at the LHC energies helps to reveal the asymptotics of hadron interactions. Analysis of the data clearly indicates that the impact-parameter elastic scattering amplitude exceed the black disk limit at the LHC energy 7TeV and the inelastic overlap function reaches its maximum value at $b>0$

  2. Sound levels in a neonatal intensive care unit significantly exceeded recommendations, especially inside incubators.

    Science.gov (United States)

    Parra, Johanna; de Suremain, Aurelie; Berne Audeoud, Frederique; Ego, Anne; Debillon, Thierry

    2017-12-01

    This study measured sound levels in a 2008 built French neonatal intensive care unit (NICU) and compared them to the 2007 American Academy of Pediatrics (AAP) recommendations. The ultimate aim was to identify factors that could influence noise levels. The study measured sound in 17 single or double rooms in the NICU. Two dosimeters were installed in each room, one inside and one outside the incubators, and these conducted measurements over a 24-hour period. The noise metrics measured were the equivalent continuous sound level (L eq ), the maximum noise level (L max ) and the noise level exceeded for 10% of the measurement period (L 10 ). The mean L eq , L 10 and L max were 60.4, 62.1 and 89.1 decibels (dBA), which exceeded the recommended levels of 45, 50 and 65 dBA (p care was correlated to an increased noise level, except for a postconceptional age below 32 weeks. The sound levels significantly exceeded the AAP recommendations, particularly inside incubators. A multipronged strategy is required to improve the sound environment and protect the neonates' sensory development. ©2017 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  3. Welding stresses

    International Nuclear Information System (INIS)

    Poirier, J.; Barbe, B.; Jolly, N.

    1976-01-01

    The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

  4. Variational formulation based analysis on growth of yield front in ...

    African Journals Online (AJOL)

    user

    The analysis of rotating disk behavior has been of great interest to many ... strain hardening using Tresca's yield condition and its associated flow rule ...... Determination of Stresses in Gas-Turbine Disks Subjected to Plastic Flow and Creep.

  5. Growth, phenological and yield responses of a bambara groundnut ...

    African Journals Online (AJOL)

    Effects of irrigation levels and seed coat colour on growth, development, yield and ... Drought tolerance in bambara groundnut landraces was achieved by reduced canopy ... and maturity, and maintaining high water use efficiency under stress.

  6. Effect of processing conditions on residual stress distributions by bead-on-plate welding after surface machining

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Mochizuki, Masahito

    2014-01-01

    Residual stress is important factor for stress corrosion cracking (SCC) that has been observed near the welded zone in nuclear power plants. Especially, surface residual stress is significant for SCC initiation. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and residual stress distribution due to surface machining is varied by the subsequent butt welding. In previous paper, authors reported that residual stress distribution generated by bead on plate welding after surface machining has a local maximum residual stress near the weld metal. The local maximum residual stress shows approximately 900 MPa that exceeds the stress threshold for SCC initiation. Therefore, for the safety improvement of nuclear power plants, a study on the local maximum residual stress is important. In this study, the effect of surface machining and welding conditions on residual stress distribution generated by welding after surface machining was investigated. Surface machining using lathe machine and bead on plate welding with tungsten inert gas (TIG) arc under various conditions were conducted for plate specimens made of SUS316L. Then, residual stress distributions were measured by X-ray diffraction method (XRD). As a result, residual stress distributions have the local maximum residual stress near the weld metal in all specimens. The values of the local maximum residual stresses are almost the same. The location of the local maximum residual stress is varied by welding condition. It could be consider that the local maximum residual stress is generated by same generation mechanism as welding residual stress in surface machined layer that has high yield stress. (author)

  7. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%.

    KAUST Repository

    Kim, Hui-Seon; Lee, Chang-Ryul; Im, Jeong-Hyeok; Lee, Ki-Beom; Moehl, Thomas; Marchioro, Arianna; Moon, Soo-Jin; Humphry-Baker, Robin; Yum, Jun-Ho; Moser, Jacques E; Grä tzel, Michael; Park, Nam-Gyu

    2012-01-01

    We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH(3)NH(3))PbI(3) as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI(2) and deposited onto a submicron-thick mesoscopic TiO(2) film, whose pores were infiltrated with the hole-conductor spiro-MeOTAD. Illumination with standard AM-1.5 sunlight generated large photocurrents (J(SC)) exceeding 17 mA/cm(2), an open circuit photovoltage (V(OC)) of 0.888 V and a fill factor (FF) of 0.62 yielding a power conversion efficiency (PCE) of 9.7%, the highest reported to date for such cells. Femto second laser studies combined with photo-induced absorption measurements showed charge separation to proceed via hole injection from the excited (CH(3)NH(3))PbI(3) NPs into the spiro-MeOTAD followed by electron transfer to the mesoscopic TiO(2) film. The use of a solid hole conductor dramatically improved the device stability compared to (CH(3)NH(3))PbI(3) -sensitized liquid junction cells.

  8. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%.

    KAUST Repository

    Kim, Hui-Seon

    2012-08-21

    We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH(3)NH(3))PbI(3) as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI(2) and deposited onto a submicron-thick mesoscopic TiO(2) film, whose pores were infiltrated with the hole-conductor spiro-MeOTAD. Illumination with standard AM-1.5 sunlight generated large photocurrents (J(SC)) exceeding 17 mA/cm(2), an open circuit photovoltage (V(OC)) of 0.888 V and a fill factor (FF) of 0.62 yielding a power conversion efficiency (PCE) of 9.7%, the highest reported to date for such cells. Femto second laser studies combined with photo-induced absorption measurements showed charge separation to proceed via hole injection from the excited (CH(3)NH(3))PbI(3) NPs into the spiro-MeOTAD followed by electron transfer to the mesoscopic TiO(2) film. The use of a solid hole conductor dramatically improved the device stability compared to (CH(3)NH(3))PbI(3) -sensitized liquid junction cells.

  9. Lead Iodide Perovskite Sensitized All-Solid-State Submicron Thin Film Mesoscopic Solar Cell with Efficiency Exceeding 9%

    Science.gov (United States)

    Kim, Hui-Seon; Lee, Chang-Ryul; Im, Jeong-Hyeok; Lee, Ki-Beom; Moehl, Thomas; Marchioro, Arianna; Moon, Soo-Jin; Humphry-Baker, Robin; Yum, Jun-Ho; Moser, Jacques E.; Grätzel, Michael; Park, Nam-Gyu

    2012-01-01

    We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH3NH3)PbI3 as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI2 and deposited onto a submicron-thick mesoscopic TiO2 film, whose pores were infiltrated with the hole-conductor spiro-MeOTAD. Illumination with standard AM-1.5 sunlight generated large photocurrents (JSC) exceeding 17 mA/cm2, an open circuit photovoltage (VOC) of 0.888 V and a fill factor (FF) of 0.62 yielding a power conversion efficiency (PCE) of 9.7%, the highest reported to date for such cells. Femto second laser studies combined with photo-induced absorption measurements showed charge separation to proceed via hole injection from the excited (CH3NH3)PbI3 NPs into the spiro-MeOTAD followed by electron transfer to the mesoscopic TiO2 film. The use of a solid hole conductor dramatically improved the device stability compared to (CH3NH3)PbI3 -sensitized liquid junction cells. PMID:22912919

  10. Brazilian Soybean Yields and Yield Gaps Vary with Farm Size

    Science.gov (United States)

    Jeffries, G. R.; Cohn, A.; Griffin, T. S.; Bragança, A.

    2017-12-01

    Understanding the farm size-specific characteristics of crop yields and yield gaps may help to improve yields by enabling better targeting of technical assistance and agricultural development programs. Linking remote sensing-based yield estimates with property boundaries provides a novel view of the relationship between farm size and yield structure (yield magnitude, gaps, and stability over time). A growing literature documents variations in yield gaps, but largely ignores the role of farm size as a factor shaping yield structure. Research on the inverse farm size-productivity relationship (IR) theory - that small farms are more productive than large ones all else equal - has documented that yield magnitude may vary by farm size, but has not considered other yield structure characteristics. We examined farm size - yield structure relationships for soybeans in Brazil for years 2001-2015. Using out-of-sample soybean yield predictions from a statistical model, we documented 1) gaps between the 95th percentile of attained yields and mean yields within counties and individual fields, and 2) yield stability defined as the standard deviation of time-detrended yields at given locations. We found a direct relationship between soy yields and farm size at the national level, while the strength and the sign of the relationship varied by region. Soybean yield gaps were found to be inversely related to farm size metrics, even when yields were only compared to farms of similar size. The relationship between farm size and yield stability was nonlinear, with mid-sized farms having the most stable yields. The work suggests that farm size is an important factor in understanding yield structure and that opportunities for improving soy yields in Brazil are greatest among smaller farms.

  11. Estimating Corporate Yield Curves

    OpenAIRE

    Antionio Diaz; Frank Skinner

    2001-01-01

    This paper represents the first study of retail deposit spreads of UK financial institutions using stochastic interest rate modelling and the market comparable approach. By replicating quoted fixed deposit rates using the Black Derman and Toy (1990) stochastic interest rate model, we find that the spread between fixed and variable rates of interest can be modeled (and priced) using an interest rate swap analogy. We also find that we can estimate an individual bank deposit yield curve as a spr...

  12. Effect of the Apulia air quality plan on PM10 and benzo(apyrene exceedances

    Directory of Open Access Journals (Sweden)

    L. Trizio

    2016-03-01

    Full Text Available During the last years, several exceedances of PM10 and benzo(apyrene limit values exceedances were recorded in Taranto, a city in southern Italy included in so-called areas at high risk of environmental crisis because of the presence of a heavy industrial district including the largest steel factory in Europe. A study of these critical pollution events showed a close correlation with the wind coming from the industrial site to the adjacent urban area. During 2011, at monitoring sites closes to the industrial area, at least the 65% of PM10 exceedances were related to wind day conditions (characterized by at least 3 consecutive hours of wind coming from 270-360±2deg with an associated speed higher than 7 m/s. For this reason, in 2012 an integrated environmental permit and a regional air quality plan were enacted to reduce pollutant emissions from industrial plants. A study of PM10 levels registered during windy days was performed during critical episodes of pollution highlighting that the difference between windy days and no windy days’ concentrations reduces from 2012 to 2014 in industrial site. False negative events (verified ex-post by observed meteorological data not identified by the forecast model - did not show a significant influence on PM concentration: PM10 values were comparable and sometimes lower than windy days levels. It is reasonable that the new scenario with a relevant reduction emissions form Ilva plant reduced the pollutants contribution from industrial area, contributing to PM10 levels decrease, also in false negative events.

  13. Planktivory in the changing Lake Huron zooplankton community: Bythotrephes consumption exceeds that of Mysis and fish

    Science.gov (United States)

    Bunnell, D.B.; Hunter, R. Douglas; Warner, D.M.; Chriscinske, M.A.; Roseman, E.F.

    2011-01-01

    Oligotrophic lakes are generally dominated by calanoid copepods because of their competitive advantage over cladocerans at low prey densities. Planktivory also can alter zooplankton community structure. We sought to understand the role of planktivory in driving recent changes to the zooplankton community of Lake Huron, a large oligotrophic lake on the border of Canada and the United States. We tested the hypothesis that excessive predation by fish (rainbow smelt Osmerus mordax, bloater Coregonus hoyi) and invertebrates (Mysis relicta, Bythotrephes longimanus) had driven observed declines in cladoceran and cyclopoid copepod biomass between 2002 and 2007. We used a field sampling and bioenergetics modelling approach to generate estimates of daily consumption by planktivores at two 91-m depth sites in northern Lake Huron, U.S.A., for each month, May-October 2007. Daily consumption was compared to daily zooplankton production. Bythotrephes was the dominant planktivore and estimated to have eaten 78% of all zooplankton consumed. Bythotrephes consumption exceeded total zooplankton production between July and October. Mysis consumed 19% of all the zooplankton consumed and exceeded zooplankton production in October. Consumption by fish was relatively unimportant - eating only 3% of all zooplankton consumed. Because Bythotrephes was so important, we explored other consumption estimation methods that predict lower Bythotrephes consumption. Under this scenario, Mysis was the most important planktivore, and Bythotrephes consumption exceeded zooplankton production only in August. Our results provide no support for the hypothesis that excessive fish consumption directly contributed to the decline of cladocerans and cyclopoid copepods in Lake Huron. Rather, they highlight the importance of invertebrate planktivores in structuring zooplankton communities, especially for those foods webs that have both Bythotrephes and Mysis. Together, these species occupy the epi-, meta- and

  14. Combining ability for maize grain yield and other agronomic ...

    African Journals Online (AJOL)

    Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress ...

  15. Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

    DEFF Research Database (Denmark)

    Waldner, P.; Thimonier, A.; Graf Pannatier, E.

    2015-01-01

    solution tended to be related to less favourable nutritional status. Context Forests have been exposed to elevated atmospheric deposition of acidifying and eutrophying sulphur and nitrogen compounds for decades. Critical loads have been identified, below which damage due to acidification and eutrophication...... are not expected to occur. Aims We explored the relationship between the exceedance of critical loads and inorganic nitrogen concentration, the base cation to aluminium ratio in soil solutions, as well as the nutritional status of trees. Methods We used recent data describing deposition, elemental concentrations....... Conclusion The findings support the hypothesis that elevated nitrogen and sulphur deposition can lead to imbalances in tree nutrition....

  16. Ballistic Transport Exceeding 28 μm in CVD Grown Graphene.

    Science.gov (United States)

    Banszerus, Luca; Schmitz, Michael; Engels, Stephan; Goldsche, Matthias; Watanabe, Kenji; Taniguchi, Takashi; Beschoten, Bernd; Stampfer, Christoph

    2016-02-10

    We report on ballistic transport over more than 28 μm in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit carrier mobilities of up to three million cm(2)/(Vs). The ballistic nature of charge transport is probed by measuring the bend resistance in cross- and square-shaped devices. Temperature-dependent measurements furthermore prove that ballistic transport is maintained exceeding 1 μm up to 200 K.

  17. Four-Terminal All-Perovskite Tandem Solar Cells Achieving Power Conversion Efficiencies Exceeding 23%

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Kai [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Dewei [University of Toledo; Wang, Changlei [University of Toledo; Wuhan University; Song, Zhaoning [University of Toledo; Yu, Yue [University of Toledo; Chen, Cong [University of Toledo; Zhao, Xingzhong [Wuhan University; Yan, Yanfa [University of Toledo

    2018-02-09

    We report on fabrication of 4-terminal all-perovskite tandem solar cells with power conversion efficiencies exceeding 23% by mechanically stacking semitransparent 1.75 eV wide-bandgap FA0.8Cs0.2Pb(I0.7Br0.3)3 perovskite top cells with 1.25 eV low-bandgap (FASnI3)0.6(MAPbI3)0.4 bottom cells. The top cells use MoOx/ITO transparent electrodes and achieve transmittance up to 70% beyond 700 nm.

  18. Stress tolerant plants

    OpenAIRE

    Rubio, Vicente; Iniesto Sánchez, Elisa; Irigoyen Miguel, María Luisa

    2014-01-01

    [EN] The invention relates to transgenic plants and methods for modulating abscisic acid (ABA) perception and signal transduction in plants. The plants find use in increasing yield in plants, particularly under abiotic stress.

  19. Investigation of the possibility of exceeding the Greenwald density limit during ECRH in T-10

    International Nuclear Information System (INIS)

    Alikaev, V.V.; Borshchegovskii, A.A.; Volkov, V.V.; Dremin, M.M.; Esipchuk, Yu.V.; Kakurin, A.M.; Kirneva, N.A.; Kislov, A.Ya.; Kislov, D.A.; Klimanov, I.V.; Kochin, V.A.; Krupin, V.A.; Krylov, S.V.; Myalton, T.B.; Novikov, A.Yu.; Notkin, G.E.; Pavlov, Yu.D.; Piterskii, V.V.; Poznyak, V.I.; Roi, I.N.

    2000-01-01

    In T-10 experiments, attempts were made to significantly exceed the Greenwald limit n-bar Gr during high-power (P ab = 750 kW) electron-cyclotron resonance heating (ECRH) and gas puffing. Formally, the density limit (n-bar e ) lim exceeding the Greenwald limit ((n-bar) e ) lim /n-bar Gr = 1.8) was achieved for q L = 8.2. However, as q L decreased, the ratio (n-bar e ) lim /n-bar Gr also decreased, approaching unity at q L ≅ 3. It was suggested that the 'current radius' (i.e., the radius of the magnetic surface enclosing the bulk of the plasma current I p ), rather than the limiter radius, was the parameter governing the value of (n-bar e ) lim . In the ECRH experiments, no substantial degradation of plasma confinement was observed up to n-bar e ∼ 0.9(n-bar e ) lim regardless of the ratio (n(bar sign) e ) lim /n-bar Gr . In different scenarios of the density growth up to (n-bar e ) lim , two types of disruptions related to the density limit were observed

  20. Jupiter's Auroral Energy Input Observed by Hisaki/EXCEED and its Modulations by Io's Volcanic Activity

    Science.gov (United States)

    Tao, C.; Kimura, T.; Tsuchiya, F.; Murakami, G.; Yoshioka, K.; Kita, H.; Yamazaki, A.; Kasaba, Y.; Yoshikawa, I.; Fujimoto, M.

    2016-12-01

    Aurora is an important indicator representing the momentum transfer from the fast-rotating outer planet to the magnetosphere and the energy input into the atmosphere through the magnetosphere-ionosphere coupling. Long-term monitoring of Jupiter's northern aurora was achieved by the Extreme Ultraviolet (EUV) spectrometer called EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) onboard JAXA's Earth-orbiting planetary space telescope Hisaki until today after its launch in September 2013. We have proceeded the statistical survey of the Jupiter's auroral energy input into the upper atmosphere. The auroral electron energy is estimated using a hydrocarbon color ratio (CR) adopted for the wavelength range of EXCEED, and the emission power in the long wavelength range 138.5-144.8 nm is used as an indicator of total emitted power before hydrocarbon absorption and auroral electron energy flux. Temporal dynamic variation of the auroral intensity was detected when Io's volcanic activity and thus EUV emission from the Io plasma torus are enhanced in the early 2015. Average of the total input power over 80 days increases by 10% with sometimes sporadically more than a factor of 3 upto 7, while the CR indicates the auroral electron energy decrease by 20% during the volcanic event compared to the other period. This indicates much more increase in the current system and Joule heating which contributes heating of the upper atmosphere. We will discuss the impact of this event on the upper atmosphere and ionosphere.

  1. Effect of Salinity and Silicon on Seed Yield and Yield Components of Purslane Portulaca oleracea L.(

    Directory of Open Access Journals (Sweden)

    Z Rahimi

    2011-01-01

    Full Text Available Abstract In order to study the effects on salinity and silicon application on yield and yield components of purslane (Portulaca oleracea L., an experiment was conducted in a completely randomized desgin with three replications and two factors consisted of four different levels of salinity using NaCl (0, 7, 14, 21dS/m and two levels of silicon (application of one mMol sodium silicate and not application. Increasing salinity concentration significantly caused a negative effect on seed yield. But yield components such as number and weight of seed were more sensitive than number of capsul in main stem in final seed yield. Application of silicon increased seed yield in control but was not significant in salinity levels and leaves and stem biomass. Seed yield and total seed weight in branches was significantly decresed. Weight of 1000 seed in main stem and branches was not significantly different in salinity levels. As a result, purslane could be extremely tolerated to saline conditions, so it seems that it can be cultivated in saline soils and arid regions. Also applied silicon can be increase yield and plant tolerance to environmental stress. Keywords: 1000 seed, Branches, Capsul, Dry weight

  2. Effect of nitrogen and water deficit type on the yield gap between the potential and attainable wheat yield

    Directory of Open Access Journals (Sweden)

    Jiangang Liu

    2015-12-01

    Full Text Available Water deficit and N fertilizer are the two primary limiting factors for wheat yield in the North China plain, the most important winter wheat (Triticum aestivum L. production area in China. Analyzing the yield gap between the potential yield and the attainable yield can quantify the potential for increasing wheat production and exploring the limiting factors to yield gap in the high-yielding farming region of North China Plain. The Decision Support System for Agrotechnology Transfer (DSSAT model was used to identify methods to increase the grain yield and decrease the gap. In order to explore the impact of N and cultivars on wheat yield in the different drought types, the climate conditions during 1981 to 2011 growing seasons was categorized into low, moderate, and severe water deficit classes according to the anomaly percentage of the water deficit rate during the entire wheat growing season. There are differences (P < 0.0001 in the variations of the potential yields among three cultivars over 30 yr. For all three water deficit types, the more recent cultivars Jimai22 and Shijiazhuang8 had higher yields compared to the older 'Jinan17'. As the N fertilizer rate increased, the yield gap decreased more substantially during the low water deficit years because of the significant increase in attainable yield. Overall, the yield gaps were smaller with less water stress. Replacement of cultivars and appropriate N fertilizer application based on the forecasted drought types can narrow the yield gap effectively.

  3. Status of fission yield measurements

    International Nuclear Information System (INIS)

    Maeck, W.J.

    1979-01-01

    Fission yield measurement and yield compilation activities in the major laboratories of the world are reviewed. In addition to a general review of the effort of each laboratory, a brief summary of yield measurement activities by fissioning nuclide is presented. A new fast reactor fission yield measurement program being conducted in the US is described

  4. Yield strength of attached copper film

    International Nuclear Information System (INIS)

    Zhang Yan; Zhang Jian-Min

    2011-01-01

    Variation of stress in attached copper film with an applied strain is measured by X-ray diffraction combined with a four-point bending method. A lower slope of the initial elastic segment of the curve of X-ray measured stress versus applied strain results from incomplete elastic strain transferred from the substrate to the film due to insufficiently strong interface cohesion. So the slope of the initial elastic segment of the X-ray stress (or X-ray strain directly) of the film against the substrate applied strain may be used to measure the film-substrate cohesive strength. The yield strength of the attached copper film is much higher than that of the bulk material and varies linearly with the inverse of the film thickness. (condensed matter: structural, mechanical, and thermal properties)

  5. Value of stress ultrasound for the diagnosis of chronic ankle instability compared to manual anterior drawer test, stress radiography, magnetic resonance imaging, and arthroscopy.

    Science.gov (United States)

    Cho, Jae Ho; Lee, Doo Hyung; Song, Hyung Keun; Bang, Joon Young; Lee, Kyung Tai; Park, Young Uk

    2016-04-01

    Clinicians frequently diagnose chronic ankle instability using the manual anterior drawer test and stress radiography. However, both examinations can yield incorrect results and do not reveal the extent of ankle instability. Stress ultrasound has been reported to be a new diagnostic tool for the diagnosis of chronic ankle instability. The purpose of this study was to assess the diagnostic value of stress ultrasound for chronic ankle instability compared to the manual anterior drawer test, stress radiography, magnetic resonance imaging (MRI), and arthroscopy. Twenty-eight consecutive patients who underwent ankle arthroscopy and subsequent modified Broström repair for treatment of chronic ankle instability were included. The arthroscopic findings were used as the reference standard. A standardized physical examination (manual anterior drawer test), stress radiography, MRI, and stress ultrasound were performed to assess the anterior talofibular ligament (ATFL) prior to operation. Ultrasound images were taken in the resting position and the maximal anterior drawer position. Grade 3 lateral instability was verified arthroscopically in all 28 cases with a clinical diagnosis (100%). Twenty-two cases showed grade III instability on the manual anterior drawer test (78.6%). Twenty-four cases displayed anterior translation exceeding 5 mm on stress radiography (86%), and talar tilt angle exceeded 15° in three cases (11 %). Nineteen cases displayed a partial chronic tear (change in thickness or signal intensity), and nine cases displayed complete tear on MRI (100%). Lax and wavy ATFL was evident on stress ultrasound in all cases (100 %). The mean value of the ATFL length was 2.8 ± 0.3 cm for the stressed condition and 2.1 ± 0.2 cm for the resting condition (p radiography. III.

  6. 49 CFR 230.24 - Maximum allowable stress.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the ultimate...

  7. Nutrient intakes of US infants, toddlers, and preschoolers meet or exceed dietary reference intakes.

    Science.gov (United States)

    Butte, Nancy F; Fox, Mary Kay; Briefel, Ronette R; Siega-Riz, Anna Maria; Dwyer, Johanna T; Deming, Denise M; Reidy, Kathleen C

    2010-12-01

    To assess the usual nutrient intakes of 3,273 US infants, toddlers, and preschoolers, aged 0 to 47 months, surveyed in the Feeding Infants and Toddlers Study (FITS) 2008; and to compare data on the usual nutrient intakes for the two waves of FITS conducted in 2002 and 2008. The FITS 2008 is a cross-sectional survey of a national random sample of US children from birth through age 47 months. Usual nutrient intakes derived from foods, beverages, and supplements were ascertained using a telephone-administered, multiple-pass 24-hour dietary recall. Infants aged birth to 5 months (n=382) and 6 to 11 months (n=505), toddlers aged 12 to 23 months (n=925), and preschoolers aged 24 to 47 months (n=1,461) were surveyed. All primary caregivers completed one 24-hour dietary recall and a random subsample (n=701) completed a second 24-hour dietary recall. The personal computer version of the Software for Intake Distribution Estimation was used to estimate the 10th, 25th, 50th, 75th, and 90th percentiles, as well as the proportions below and above cutoff values defined by the Dietary Reference Intakes or the 2005 Dietary Guidelines for Americans. Usual nutrient intakes met or exceeded energy and protein requirements with minimal risk of vitamin and mineral deficiencies. The usual intakes of antioxidants, B vitamins, bone-related nutrients, and other micronutrients were adequate relative to the Adequate Intakes or Estimated Average Requirements, except for iron and zinc in a small subset of older infants, and vitamin E and potassium in toddlers and preschoolers. Intakes of synthetic folate, preformed vitamin A, zinc, and sodium exceeded Tolerable Upper Intake Level in a significant proportion of toddlers and preschoolers. Macronutrient distributions were within acceptable macronutrient distribution ranges, except for dietary fat, in some toddlers and preschoolers. Dietary fiber was low in the vast majority of toddlers and preschoolers, and saturated fat intakes exceeded

  8. Kinetics model of bainitic transformation with stress

    Science.gov (United States)

    Zhou, Mingxing; Xu, Guang; Hu, Haijiang; Yuan, Qing; Tian, Junyu

    2018-01-01

    Thermal simulations were conducted on a Gleeble 3800 simulator. The main purpose is to investigate the effects of stress on the kinetics of bainitic transformation in a Fe-C-Mn-Si advanced high strength bainitic steel. Previous studies on modeling the kinetics of stress affected bainitic transformation only considered the stress below the yield strength of prior austenite. In the present study, the stress above the yield strength of prior austenite is taken into account. A new kinetics model of bainitic transformation dependent on the stress (including the stresses below and above the yield strength of prior austenite) and the transformation temperature is proposed. The new model presents a good agreement with experimental results. In addition, it is found that the acceleration degree of stress on bainitic transformation increases with the stress whether its magnitude is below or above the yield strength of austenite, but the increasing rate gradually slows down when the stress is above the yield strength of austenite.

  9. Spot volume exceeds 2 million lbs (again); restricted price hits $10/lb

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    This article is the January 1995 uranium market summary. Volume on the spot concentrates market exceeded 2 million lbs equivalent for the second consecutive month. Six deals took place; four in the spot concentrates market, one in the conversion market, and one in the enrichment market. No deals took place in the medium or long-term market. The upper end of the restricted price range reached $10.00 per lb U3O8, its highest level since December 1993. The lower end of the restricted price range strengthened to $9.75. The lower end of the spot conversion price range strengthed to $5.70 per kg U, and SWU prices firmed to the $75.00 to $87.00 level

  10. Technical meeting on progress in managing, and limiting the consequences of events exceeding the design basis

    International Nuclear Information System (INIS)

    Fabian, H.

    2004-01-01

    The Technical Groups on 'Reactor Safety' and 'Thermodynamics and Fluid Dynamics' of the Kerntechnische Gesellschaft e.V. organized a joint technical meeting on 'Progress in Managing, and Limiting the Consequences of, Events Exceeding the Design Basis' at the FTU Training Center of the Karlsruhe Research Center. The topic chosen, the papers presented, the presenters, and the non-technical part of the program met with lively interest on the part of institutions in the nuclear field. These were the objectives of the technical meeting: - Establishing a forum for communicating relevant topics. - In-depth discussion of the main topic, i.e. the advanced development of reactor safety, research in the field, and its application, in twenty selected papers presented by speakers from different institutions. - Presentation of topical work in a nuclear technology institution, the Karlsruhe Research Center. (orig.) [de

  11. Positive and negative gain exceeding unity magnitude in silicon quantum well metal-oxide-semiconductor transistors

    Science.gov (United States)

    Hu, Gangyi; Wijesinghe, Udumbara; Naquin, Clint; Maggio, Ken; Edwards, H. L.; Lee, Mark

    2017-10-01

    Intrinsic gain (AV) measurements on Si quantum well (QW) n-channel metal-oxide-semiconductor (NMOS) transistors show that these devices can have |AV| > 1 in quantum transport negative transconductance (NTC) operation at room temperature. QW NMOS devices were fabricated using an industrial 45 nm technology node process incorporating ion implanted potential barriers to define a lateral QW in the conduction channel under the gate. While NTC at room temperature arising from transport through gate-controlled QW bound states has been previously established, it was unknown whether the quantum NTC mechanism could support gain magnitude exceeding unity. Bias conditions were found giving both positive and negative AV with |AV| > 1 at room temperature. This result means that QW NMOS devices could be useful in amplifier and oscillator applications.

  12. A revised formula for 3-body recombination that cannot exceed the unitarity limit

    International Nuclear Information System (INIS)

    Greene, Chris H.; Esry, B.D.; Suno, H.

    2004-01-01

    We discuss the recent developments in theory and experiment that bear on our understanding of three-body recombination at ultracold temperatures. Some of these predictions include the fourth-power dependence of the three-body rate on the two-body scattering lenght a, the appearance of quantum mechanical shape resonance and Feshbach resonances, and the existence of destructive interference minima at large positive scattering lenghts. At very large scattering lenghts, however, the a 4 dependence of the recombination rate eventually will exceed the unitarity limit. We propose in this paper a simple way to correct this problem, permitting an approximate extension of previous predictions to slightly higher energies above the three-body fragmentation threshold. A preliminary comparison is carried out with a very recent experiment by Grimm and coworkers, showing reasonable agreement

  13. Response Load Extrapolation for Wind Turbines during Operation Based on Average Conditional Exceedance Rates

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Naess, Arvid; Saha, Nilanjan

    2011-01-01

    to cases where the Gumbel distribution is the appropriate asymptotic extreme value distribution. However, two extra parameters are introduced by which a more general and flexible class of extreme value distributions is obtained with the Gumbel distribution as a subclass. The general method is implemented...... within a hierarchical model where the variables that influence the loading are divided into ergodic variables and time-invariant non-ergodic variables. The presented method for statistical response load extrapolation was compared with the existing methods based on peak extrapolation for the blade out......The paper explores a recently developed method for statistical response load (load effect) extrapolation for application to extreme response of wind turbines during operation. The extrapolation method is based on average conditional exceedance rates and is in the present implementation restricted...

  14. Global biomass production potentials exceed expected future demand without the need for cropland expansion.

    Science.gov (United States)

    Mauser, Wolfram; Klepper, Gernot; Zabel, Florian; Delzeit, Ruth; Hank, Tobias; Putzenlechner, Birgitta; Calzadilla, Alvaro

    2015-11-12

    Global biomass demand is expected to roughly double between 2005 and 2050. Current studies suggest that agricultural intensification through optimally managed crops on today's cropland alone is insufficient to satisfy future demand. In practice though, improving crop growth management through better technology and knowledge almost inevitably goes along with (1) improving farm management with increased cropping intensity and more annual harvests where feasible and (2) an economically more efficient spatial allocation of crops which maximizes farmers' profit. By explicitly considering these two factors we show that, without expansion of cropland, today's global biomass potentials substantially exceed previous estimates and even 2050s' demands. We attribute 39% increase in estimated global production potentials to increasing cropping intensities and 30% to the spatial reallocation of crops to their profit-maximizing locations. The additional potentials would make cropland expansion redundant. Their geographic distribution points at possible hotspots for future intensification.

  15. Gusts and shear within hurricane eyewalls can exceed offshore wind turbine design standards

    Science.gov (United States)

    Worsnop, Rochelle P.; Lundquist, Julie K.; Bryan, George H.; Damiani, Rick; Musial, Walt

    2017-06-01

    Offshore wind energy development is underway in the U.S., with proposed sites located in hurricane-prone regions. Turbine design criteria outlined by the International Electrotechnical Commission do not encompass the extreme wind speeds and directional shifts of hurricanes stronger than category 2. We examine a hurricane's turbulent eyewall using large-eddy simulations with Cloud Model 1. Gusts and mean wind speeds near the eyewall of a category 5 hurricane exceed the current Class I turbine design threshold of 50 m s-1 mean wind and 70 m s-1 gusts. Largest gust factors occur at the eye-eyewall interface. Further, shifts in wind direction suggest that turbines must rotate or yaw faster than current practice. Although current design standards omit mention of wind direction change across the rotor layer, large values (15-50°) suggest that veer should be considered.

  16. How much Baltic salmon can be consumed without exceeding the tolerable safety limit ?

    Energy Technology Data Exchange (ETDEWEB)

    Kristiansen, H.R. [Mobile Nutrients Ltd. (Denmark)

    2004-09-15

    Because Baltic salmon is a top predator preying on sprat, herring and tobis, it is very vulnerable to contamination with dioxin and PCBs. The EU safety limit (SL) for fish is 4 picogram (pg) WHOTEQ g{sup -1} fresh fish. In April 2004, Danish commercial salmon fishing was banned to in the Baltic sea around Bornholm and Gotland (mainly ICES areas 25, 26), because the Food Administration reported dioxin levels exceeding the intervention level of 3 pg g{sup -1} fresh salmon. Their report was based on data from 10 individual salmon, and 3 pooled samples, each with 10 salmon. Since dioxins are widespread in the environment, the human population face a trade off to produce sufficient food that is safe to eat and avoid eating contaminated food. The world population is increasing, and the demand for healthy food is steadily increasing. Consequently, there is a need for risk assessments, where the consequences of eating foods with different grades of contamination is evaluated. The evaluation must be based on data of high quality, and because dioxin accumulation is a slow proces, the risk assessments should consider long time periods of months and years instead of days and weeks. The purpose of the present study is to evaluate the statistical variation of dioxin data from Baltic herring and salmon. The data are used to calculate the quantity of herring and salmon, that humans of different body weight can eat without exceeding the tolerable daily intake (TDI). (In dietary recommendations exposure from dairy products etc. must also be taken into account). A PCDD/F box model is proposed that subtract losses during cooking and postprandially.

  17. Was it worthwhile? Where have the benefits of rooftop solar photovoltaic generation exceeded the cost?

    Science.gov (United States)

    Vaishnav, Parth; Horner, Nathaniel; Azevedo, Inês L.

    2017-09-01

    We estimate the lifetime magnitude and distribution of the private and public benefits and costs of currently installed distributed solar PV systems in the United States. Using data for recently-installed systems, we estimate the balance of benefits and costs associated with installing a non-utility solar PV system today. We also study the geographical distribution of the various subsidies that are made available to owners of rooftop solar PV systems, and compare it to distributions of population and income. We find that, after accounting for federal subsidies and local rebates and assuming a discount rate of 7%, the private benefits of new installations will exceed private costs only in seven of the 19 states for which we have data and only if customers can sell excess power to the electric grid at the retail price. These states are characterized by abundant sunshine (California, Texas and Nevada) or by high electricity prices (New York). Public benefits from reduced air pollution and climate change impact exceed the costs of the various subsidies offered system owners for less than 10% of the systems installed, even assuming a 2% discount rate. Subsidies flowed disproportionately to counties with higher median incomes in 2006. In 2014, the distribution of subsidies was closer to that of population income, but subsidies still flowed disproportionately to the better-off. The total, upfront, subsidy per kilowatt of installed capacity has fallen from 5200 in 2006 to 1400 in 2014, but the absolute magnitude of subsidy has soared as installed capacity has grown explosively. We see considerable differences in the balance of costs and benefits even within states, indicating that local factors such as system price and solar resource are important, and that policies (e.g. net metering) could be made more efficient by taking local conditions into account.

  18. General aviation accidents related to exceedance of airplane weight/center of gravity limits.

    Science.gov (United States)

    Boyd, Douglas D

    2016-06-01

    Obesity, affects a third of the US population and its corollary occupant weight adversely impacts safe flight operations. Increased aircraft weight results in longer takeoff/landing distances, degraded climb gradients and airframe failure may occur in turbulence. In this study, the rate, temporal changes, and lethality of accidents in piston-powered, general aviation aircraft related to exceeding the maximum aircraft weight/center of gravity (CG) limits were determined. Nation-wide person body mass were from the National Health and Nutrition Examination Survey. The NTSB database was used to identify accidents related to operation of aircraft outside of their weight/CG envelope. Statistical analyses employed T-tests, proportion tests and a Poisson distribution. While the average body mass climbed steadily (p<0.001) between 1999 and 2014 the rate of accidents related to exceedance of the weight/CG limits did not change (p=0.072). However, 57% were fatal, higher (p<0.001) than the 21% for mishaps attributed to other causes/factors. The majority (77%) of accidents were due to an overloaded aircraft operating within its CG limits. As to the phase of flight, accidents during takeoff and those occurring enroute carried the lowest (50%) and highest (85%) proportion of fatal accidents respectively. While the rate of general aviation accidents related to operating an aircraft outside of its weight/CG envelope has not increased over the past 15 years, these types of accidents carry a high risk of fatality. Airmen should be educated as to such risks and to dispel the notion held by some that flights may be safely conducted with an overloaded aircraft within its CG limits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Most American Academy of Orthopaedic Surgeons' online patient education material exceeds average patient reading level.

    Science.gov (United States)

    Eltorai, Adam E M; Sharma, Pranav; Wang, Jing; Daniels, Alan H

    2015-04-01

    Advancing health literacy has the potential to improve patient outcomes. The American Academy of Orthopaedic Surgeons' (AAOS) online patient education materials serve as a tool to improve health literacy for orthopaedic patients; however, it is unknown whether the materials currently meet the National Institutes of Health/American Medical Association's recommended sixth grade readability guidelines for health information or the mean US adult reading level of eighth grade. The purposes of this study were (1) to evaluate the mean grade level readability of online AAOS patient education materials; and (2) to determine what proportion of the online materials exceeded recommended (sixth grade) and mean US (eighth grade) reading level. Reading grade levels for 99.6% (260 of 261) of the online patient education entries from the AAOS were analyzed using the Flesch-Kincaid formula built into Microsoft Word software. Mean grade level readability of the AAOS patient education materials was 9.2 (SD ± 1.6). Two hundred fifty-one of the 260 articles (97%) had a readability score above the sixth grade level. The readability of the AAOS articles exceeded the sixth grade level by an average of 3.2 grade levels. Of the 260 articles, 210 (81%) had a readability score above the eighth grade level, which is the average reading level of US adults. Most of the online patient education materials from the AAOS had readability levels that are far too advanced for many patients to comprehend. Efforts to adjust the readability of online education materials to the needs of the audience may improve the health literacy of orthopaedic patients. Patient education materials can be made more comprehensible through use of simpler terms, shorter sentences, and the addition of pictures. More broadly, all health websites, not just those of the AAOS, should aspire to be comprehensible to the typical reader.

  20. Nonsynonymous substitution in abalone sperm fertilization genes exceeds substitution in introns and mitochondrial DNA

    Science.gov (United States)

    Metz, Edward C.; Robles-Sikisaka, Refugio; Vacquier, Victor D.

    1998-01-01

    Strong positive Darwinian selection acts on two sperm fertilization proteins, lysin and 18-kDa protein, from abalone (Haliotis). To understand the phylogenetic context for this dramatic molecular evolution, we obtained sequences of mitochondrial cytochrome c oxidase subunit I (mtCOI), and genomic sequences of lysin, 18-kDa, and a G protein subunit. Based on mtDNA differentiation, four north Pacific abalone species diverged within the past 2 million years (Myr), and remaining north Pacific species diverged over a period of 4–20 Myr. Between-species nonsynonymous differences in lysin and 18-kDa exons exceed nucleotide differences in introns by 3.5- to 24-fold. Remarkably, in some comparisons nonsynonymous substitutions in lysin and 18-kDa genes exceed synonymous substitutions in mtCOI. Lysin and 18-kDa intron/exon segments were sequenced from multiple red abalone individuals collected over a 1,200-km range. Only two nucleotide changes and two sites of slippage variation were detected in a total of >29,000 nucleotides surveyed. However, polymorphism in mtCOI and a G protein intron was found in this species. This finding suggests that positive selection swept one lysin allele and one 18-kDa allele to fixation. Similarities between mtCOI and lysin gene trees indicate that rapid adaptive evolution of lysin has occurred consistently through the history of the group. Comparisons with mtCOI molecular clock calibrations suggest that nonsynonymous substitutions accumulate 2–50 times faster in lysin and 18-kDa genes than in rapidly evolving mammalian genes. PMID:9724763

  1. Effective stress, friction and deep crustal faulting

    Science.gov (United States)

    Beeler, N.M.; Hirth, Greg; Thomas, Amanda M.; Burgmann, Roland

    2016-01-01

    Studies of crustal faulting and rock friction invariably assume the effective normal stress that determines fault shear resistance during frictional sliding is the applied normal stress minus the pore pressure. Here we propose an expression for the effective stress coefficient αf at temperatures and stresses near the brittle-ductile transition (BDT) that depends on the percentage of solid-solid contact area across the fault. αf varies with depth and is only near 1 when the yield strength of asperity contacts greatly exceeds the applied normal stress. For a vertical strike-slip quartz fault zone at hydrostatic pore pressure and assuming 1 mm and 1 km shear zone widths for friction and ductile shear, respectively, the BDT is at ~13 km. αf near 1 is restricted to depths where the shear zone is narrow. Below the BDT αf = 0 is due to a dramatically decreased strain rate. Under these circumstances friction cannot be reactivated below the BDT by increasing the pore pressure alone and requires localization. If pore pressure increases and the fault localizes back to 1 mm, then brittle behavior can occur to a depth of around 35 km. The interdependencies among effective stress, contact-scale strain rate, and pore pressure allow estimates of the conditions necessary for deep low-frequency seismicity seen on the San Andreas near Parkfield and in some subduction zones. Among the implications are that shear in the region separating shallow earthquakes and deep low-frequency seismicity is distributed and that the deeper zone involves both elevated pore fluid pressure and localization.

  2. Evaluation of Yield and Yield Components of Some Pinto bean (Phaseolus vulgaris L. Genotypes under Late Season Water Deficit Conditions

    Directory of Open Access Journals (Sweden)

    somayyeh soheili movahhed

    2017-10-01

    Full Text Available Introduction Drought or water deficit stress is the most important environmental factor which has severe negative impacts on crop yields, especially when the water stress occurs in the flowering stage. Iran is located in arid and semi-arid areas, therefore, attention to the effects of water deficit stress in different stages of plants growth seems necessary. Bean (Phaseolus vulgaris L. is one of the most important legumes that has a major contribution to human diet and provides an important part of the human protein. According to studies, cultivation areas of legumes in Iran are about 97300 hectares and its total production is about 208350 tons of grain. Bean is a fast-growing plant (Tran and Singh, 2002, thus soil water must be sufficiently available to ensure its desirable growth and yield. The aim of this study was to investigate the effect of drought stress on yield and yield components of some pinto bean (Phaseolus vulgaris L. cultivated in Zanjan province. Materials and methods An experiment was conducted as spilt plot based on randomized complete block design with four replications in Zanjan university research farm. Irrigation levels (control and drought stress and genotypes (Local khomein, Sadri, Ks21193 and Ks21189 were set in the main and subplot, respectively. Water deficit stress was applied during flowering stage (50% of the plants were at anthesis. Sampling was performed to measure yield and yield components at the end of the growth period and final maturity. In this experiment number of pod per Plant, numberof grain per pod, 100 grain weight, grain yield, biological yield and harvest index were measured. Results and Discussion In this experiment it was observed that drought stress, genotype and interact irrigation×genotyps were significantly for all traits except biological yield. Drought stress reduced number of pod perplant, number of grain per pod, 100 grain weight, grain yield, biological yield and Harvest Index. Results

  3. Effect of Integrated Nutrient Management on Yield and Yield ...

    African Journals Online (AJOL)

    Declining soil fertility is one of the major problems causing yield reduction of barley ... (VC) with inorganic NP on growth, yield and yield components of food barley. ... The experiments were laid out in a randomized complete block design with ...

  4. 40 CFR 141.209 - Special notice for nitrate exceedances above MCL by non-community water systems (NCWS), where...

    Science.gov (United States)

    2010-07-01

    ... Water Violations § 141.209 Special notice for nitrate exceedances above MCL by non-community water... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Special notice for nitrate exceedances above MCL by non-community water systems (NCWS), where granted permission by the primacy agency under Â...

  5. Yield enhancement with DFM

    Science.gov (United States)

    Paek, Seung Weon; Kang, Jae Hyun; Ha, Naya; Kim, Byung-Moo; Jang, Dae-Hyun; Jeon, Junsu; Kim, DaeWook; Chung, Kun Young; Yu, Sung-eun; Park, Joo Hyun; Bae, SangMin; Song, DongSup; Noh, WooYoung; Kim, YoungDuck; Song, HyunSeok; Choi, HungBok; Kim, Kee Sup; Choi, Kyu-Myung; Choi, Woonhyuk; Jeon, JoongWon; Lee, JinWoo; Kim, Ki-Su; Park, SeongHo; Chung, No-Young; Lee, KangDuck; Hong, YoungKi; Kim, BongSeok

    2012-03-01

    A set of design for manufacturing (DFM) techniques have been developed and applied to 45nm, 32nm and 28nm logic process technologies. A noble technology combined a number of potential confliction of DFM techniques into a comprehensive solution. These techniques work in three phases for design optimization and one phase for silicon diagnostics. In the DFM prevention phase, foundation IP such as standard cells, IO, and memory and P&R tech file are optimized. In the DFM solution phase, which happens during ECO step, auto fixing of process weak patterns and advanced RC extraction are performed. In the DFM polishing phase, post-layout tuning is done to improve manufacturability. DFM analysis enables prioritization of random and systematic failures. The DFM technique presented in this paper has been silicon-proven with three successful tape-outs in Samsung 32nm processes; about 5% improvement in yield was achieved without any notable side effects. Visual inspection of silicon also confirmed the positive effect of the DFM techniques.

  6. Neurological and neurophysiological examinations of workers exposed to arsenic levels exceeding hygiene standards

    Directory of Open Access Journals (Sweden)

    Halina Sińczuk-Walczak

    2014-12-01

    Full Text Available Objectives: The assessment of the neurotoxic effect of arsenic (As and its inorganic compounds is still the subject of interest due to a growing As application in a large array of technologies and the need to constantly verify the principles of prevention and technological parameters. The aim of this study was to determine the status of the nervous system (NS in workers exposed to As at concentrations exceeding hygiene standards (Threshold Limit Values (TLV – 10 μg/m3, Biological Exposure Index (BEI – 35 μg/l and to analyze the relationship between the NS functional state, species of As in urine and As levels in the workplace air. Material and Methods: The study group comprised 21 men (mean age: 47.43±7.59 employed in a copper smelting factory (mean duration of employment: 22.29±11.09. The control group comprised 16 men, matched by age and work shifts. Arsenic levels in the workplace air (As-A ranged from 0.7 to 92.3 μg/m3; (M = 25.18±28.83. The concentration of total arsenic in urine (Astot-U ranged from 17.35 to 434.68 μg/l (M = 86.82±86.6. Results: Syndrome of peripheral nervous system (PNS was manifested by extremity fatigue (28.6%, extremity pain (33.3% and paresthesia in the lower extremities (33.3%, as well as by neuropathy-type mini-symptoms (23.8%. Electroneurographic (ENeG tests of peroneal nerves showed significantly decreased response amplitude with normal values of motor conduction velocity (MCV. Stimulation of sural nerves revealed a significantly slowed sensory conduction velocity (SCV and decreased sensory potential amplitude. Neurophysiological parameters and the results of biological and environmental monitoring showed a relationship between Astot, AsIII (trivalent arsenic, the sum of iAs (AsIII+AsV (pentavalent arsenic+MMA (monomethylarsonic acid concentration in urine and As levels in the air. Conclusions: The results of the study demonstrate that occupational exposure to inorganic arsenic levels exceeding hygiene

  7. Efeitos do estresse térmico sobre a produção, composição química do leite e respostas termorreguladoras de cabras da raça alpina Thermal stress effects on milk yield and chemical composition and thermoregulatory responses of lactating alpines goats

    Directory of Open Access Journals (Sweden)

    Lúcia Helena de Albuquerque Brasil

    2000-12-01

    Full Text Available Seis cabras da raça Alpina, com produção média de leite de 2,5 kg/dia, foram distribuídas aleatoriamente em dois grupos de três e submetidas à termoneutralidade ou estresse térmico por 56 dias em câmara climática. Usou-se um delineamento estatístico "crossover". A temperatura média do ar diurna, incluindo radiação solar simulada, foi de 33,84ºC. Os animais estressados aumentaram a freqüência respiratória, o volume-minuto respiratório, a termólise-evaporativa respiratória, temperatura retal e a taxa de sudorese, enquanto o volume corrente respiratório e o volume globular diminuíram. Houve também perda de peso, redução da ingestão de alimentos e duplicação do consumo de água. A produção de leite e a porcentagem de gordura, proteína, lactose e sólidos totais diminuíram. Os teores de cloretos, cálcio e fósforo não sofreram alteração. Concluiu-se que, para manter a homeotermia, as cabras mobilizaram o sistema respiratório e sudoríparo para perder calor. A alta temperatura ambiente efetiva reduziu a produção e os teores de alguns componentes do leite.Six Alpine goats with an average milk yield of 2.5 kg/day were randomly assigned to two groups of three and allotted to thermoneutral or heat stress conditions, for 56 days in climate chamber room. A crossover experimental design was used. The goats under heat stress were exposed to a diurnal average air temperature plus simulated solar radiation of 33. 84ºC. The heat-stressed goats showed elevated respiratory frequency, respiratory minute volume, respiratory evaporation, rectal temperature and sweating rate, while the tidal volume and packed cell volume decreased. Further weight loss, decreased feed intake, and their water consumption doubled. The milk yield, the percentage of fat, protein, lactose and total solid contents decreased. The contents of chloride, calcium and phosphorus did not change. The goats mobilized the respiratory and sweating systems to

  8. Cool-down flow-rate limits imposed by thermal stresses in LNG pipelines

    Science.gov (United States)

    Novak, J. K.; Edeskuty, F. J.; Bartlit, J. R.

    Warm cryogenic pipelines are usually cooled to operating temperature by a small, steady flow of the liquid cryogen. If this flow rate is too high or too low, undesirable stresses will be produced. Low flow-rate limits based on avoidance of stratified two-phase flow were calculated for pipelines cooled with liquid hydrogen or nitrogen. High flow-rate limits for stainless steel and aluminum pipelines cooled by liquid hydrogen or nitrogen were determined by calculating thermal stress in thick components vs flow rate and then selecting some reasonable stress limits. The present work extends these calculations to pipelines made of AISI 304 stainless steel, 6061 aluminum, or ASTM A420 9% nickel steel cooled by liquid methane or a typical natural gas. Results indicate that aluminum and 9% nickel steel components can tolerate very high cool-down flow rates, based on not exceeding the material yield strength.

  9. An integrated approach to identify the origin of PM10 exceedances.

    Science.gov (United States)

    Amodio, M; Andriani, E; de Gennaro, G; Demarinis Loiotile, A; Di Gilio, A; Placentino, M C

    2012-09-01

    This study was aimed to the development of an integrated approach for the characterization of particulate matter (PM) pollution events in the South of Italy. PM(10) and PM(2.5) daily samples were collected from June to November 2008 at an urban background site located in Bari (Puglia Region, South of Italy). Meteorological data, particle size distributions and atmospheric dispersion conditions were also monitored in order to provide information concerning the different features of PM sources. The collected data allowed suggesting four indicators to characterize different PM(10) exceedances. PM(2.5)/PM(10) ratio, natural radioactivity, aerosol maps and back-trajectory analysis and particle distributions were considered in order to evaluate the contribution of local anthropogenic sources and to determine the different origins of intrusive air mass coming from long-range transport, such as African dust outbreaks and aerosol particles from Central and Eastern Europe. The obtained results were confirmed by applying principal component analysis to the number particle concentration dataset and by the chemical characterization of the samples (PM(10) and PM(2.5)). The integrated approach for PM study suggested in this paper can be useful to support the air quality managers for the development of cost-effective control strategies and the application of more suitable risk management approaches.

  10. 137Cs activity concentration in wild boar meat may still exceed the permitted levels

    Directory of Open Access Journals (Sweden)

    Rachubik J.

    2012-04-01

    Full Text Available The radiocaesium activity concentration may still remain high in natural products such as game meat, wild mushrooms, and forest berries even more than two decades after the Chernobyl accident. The results of regular control studies of game meat conducted in Poland showed wild boars as the most contaminated game animals. It is well documented that some mushrooms, readily consumed by animals, show high ability to accumulate caesium radioisotopes. Bay bolete, one of the most wide-spread mushroom species in Poland, reveals a unique radiocaesium accumulation feature. Moreover, deer truffle, containing also particularly high levels of radiocaesium, could be another radionu-clide source for wild boars. Furthermore, animals consuming deer truffles could digest contaminated soil components. Among 94 wild boar meat samples analysed in 2008–2009, two exceeded the permitted level. Hence, some precautions should be taken in the population with an elevated intake of wild boar meat. Moreover, since each hunted wild boar is examined for the presence of Trichinella larvae, regular measurements of radiocaesium concentrations in these animals may be advisable for enhancing consumer safety.

  11. How to evaluate the risks of exceeding limits: geostatistical models and their application to air pollution

    International Nuclear Information System (INIS)

    Fouquet, Ch. de; Deraisme, J.; Bobbia, M.

    2007-01-01

    Geo-statistics is increasingly applied to the study of environmental risks in a variety of sectors, especially in the fields of soil decontamination and the evaluation of the risks due to air pollution. Geo-statistics offers a rigorous stochastic modeling approach that makes it possible to answer questions expressed in terms of uncertainty and risk. This article focusses on nonlinear geo-statistical methods, based on the Gaussian random function model, whose essential properties are summarised. We use two examples to characterize situations where direct and thus rapid methods provide appropriate solutions and cases that inevitably require more laborious simulation techniques. Exposure of the population of the Rouen metropolitan area to the risk of NO 2 pollution is assessed by simulations, but the surface area where the pollution exceeds the threshold limit can be easily estimated with nonlinear conditional expectation techniques. A second example is used to discuss the bias introduced by direct simulation, here of a percentile of daily SO 2 concentration for one year in the city of Le Havre; an operational solution is proposed. (authors)

  12. Kyoto and beyond : A plan of action to meet and exceed Manitoba's Kyoto targets

    International Nuclear Information System (INIS)

    2002-10-01

    This document represents the next step in Manitoba's effort to mitigate the effects of climate change. A message from the Manitoba Premier and the Minister of Conservation of Manitoba are included in the introduction. The Action Plan is based in part on the discussion among climate experts and public input gathered in the course of the 2001 task force and the 2001 public forum on climate change. A rise in average global temperatures is affecting most of the planet, which is due in part to the upsetting of the balance of greenhouse gases in the atmosphere as a result of human activities. It is affecting weather patterns, water, agriculture, forests, health and welfare, and life in the North. The Manitoba government is committed to meeting and exceeding the reduction targets set under the Kyoto Protocol through renewable electricity, Selkirk conversion, ethanol, methane capture, and other measures targeted toward industry. Energy efficiency also plays a big part in the process of reducing greenhouse gas emissions. The government is leading by example, and also investing in knowledge. It is promoting technology development and innovation while enhancing awareness and understanding. All sectors are being encouraged to implement appropriate measures. The various initiatives undertaken by each department and organization under each of those headings are described. figs

  13. 137Cs activity concentration in wild boar meat may still exceed the permitted levels

    Science.gov (United States)

    Rachubik, J.

    2012-04-01

    The radiocaesium activity concentration may still remain high in natural products such as game meat, wild mushrooms, and forest berries even more than two decades after the Chernobyl accident. The results of regular control studies of game meat conducted in Poland showed wild boars as the most contaminated game animals. It is well documented that some mushrooms, readily consumed by animals, show high ability to accumulate caesium radioisotopes. Bay bolete, one of the most wide-spread mushroom species in Poland, reveals a unique radiocaesium accumulation feature. Moreover, deer truffle, containing also particularly high levels of radiocaesium, could be another radionu-clide source for wild boars. Furthermore, animals consuming deer truffles could digest contaminated soil components. Among 94 wild boar meat samples analysed in 2008-2009, two exceeded the permitted level. Hence, some precautions should be taken in the population with an elevated intake of wild boar meat. Moreover, since each hunted wild boar is examined for the presence of Trichinella larvae, regular measurements of radiocaesium concentrations in these animals may be advisable for enhancing consumer safety.

  14. Biomaterials recycling: bioglasses obtained from reuse of hydroxyapatite (HA) bovine bone with term exceeded validity

    International Nuclear Information System (INIS)

    Silva, A.C.; Santos, S.C.; Braga, F.J.C.; Aparecida, A.H.

    2012-01-01

    The hydroxyapatite (HA) is a reference bioceramic for bone replacement and regeneration medical practice, becoming one of the most produced and researched bone graft material. Since it is a material for biomedical application, the manufacture and storage of this bioceramic must comply with severe conservation criteria, and its validity date is the lawful major factor for disposal. Materials with the exceeded expiration date are usually discarded and incinerated, resulting in ash, environmental contamination and energy expenditure. This study evaluates the possibility of reuse of bovine HA collected after its validity date as raw material to obtain bioglass, aiming to natural resources saving and environmental emissions mitigation. 45S5 similar compositions were obtained by melting the materials at 1500 ° C, followed by rapid cooling and annealing thermal treatment (500 ° C for 2h), analytical grade chemical reagents were used to set the final composition. The obtained materials were characterized by X-ray diffraction, infrared spectroscopy (FT-IR), and hydrolysis resistance techniques. The results of comparative chemical resistance (Hydrolytic) tests indicate the potential use of the materials developed for bone replacement applications. (author)

  15. Irrigation offsets wheat yield reductions from warming temperatures

    Science.gov (United States)

    Tack, Jesse; Barkley, Andrew; Hendricks, Nathan

    2017-11-01

    Temperature increases due to climate change are expected to cause substantial reductions in global wheat yields. However, uncertainty remains regarding the potential role for irrigation as an adaptation strategy to offset heat impacts. Here we utilize over 7000 observations spanning eleven Kansas field-trial locations, 180 varieties, and 29 years to show that irrigation significantly reduces the negative impact of warming temperatures on winter wheat yields. Dryland wheat yields are estimated to decrease about eight percent for every one-degree Celsius increase in temperature, yet irrigation completely offsets this negative impact in our sample. As in previous studies, we find that important interactions exist between heat stress and precipitation for dryland production. Here, uniquely, we observe both dryland and irrigated trials side-by-side at the same locations and find that precipitation does not provide the same reduction in heat stress as irrigation. This is likely to be because the timing, intensity, and volume of water applications influence wheat yields, so the ability to irrigate—rather than relying on rainfall alone—has a stronger influence on heat stress. We find evidence of extensive differences of water-deficit stress impacts across varieties. This provides some evidence of the potential for adapting to hotter and drier climate conditions using optimal variety selection. Overall, our results highlight the critical role of water management for future global food security. Water scarcity not only reduces crop yields through water-deficit stress, but also amplifies the negative effects of warming temperatures.

  16. Structural strength assessment of the reconstructed road structure in terms of the loading time and yield criterion

    Science.gov (United States)

    Mazurek, Grzegorz; Iwański, Marek

    2018-05-01

    This article reports the results of numerical simulations of the stress-strain states in the rebuilt road structure compared to the solutions contained in the Polish Catalogue, with the true characteristics of the layer materials taken into account. In the case analysed, a cold-recycled base layer with foamed bitumen as a recycling agent was used. The presented analysis is complementary to the mandatory in Poland procedure of mechanistic pavement design based on a linear elastic model. The temperature distribution in the road structure was analysed at the reference temperature of 40°C on the asphalt layer surface. The loading time was included in the computer simulations through the use of the classic generalized Maxwell model and thus the stiffness-time history of the layers had to be determined. For this purpose, the dynamic modulus E* tests of the loading time frequency from 0.1 Hz to 20 Hz were carried out, and the yield point was modelled using the Coulomb-Mohr failure criterion calculated on the basis of triaxial compression tests. The analytical solution to the problem was found with ABAQUS. The results demonstrate that the high temperature of asphalt layers and long loading time noticeably reduces the stiffness modulus in those layers. That reduction changes the principal stress levels, which significantly influences the shear stress both in the recycled base layer and in the subgrade soil. Should the yield point be exceeded rapidly in the recycled layer, the horizontal stresses in the asphalt layers will increase and adversely affect the durability of the reconstructed road pavement structure, especially in the zones of slow heavy vehicle traffic.

  17. Residual stresses in plastic random systems

    NARCIS (Netherlands)

    Alava, M.J.; Karttunen, M.E.J.; Niskanen, K.J.

    1995-01-01

    We show that yielding in elastic plastic materials creates residual stresses when local disorder is present. The intensity of these stresses grows with the external stress and degree of initial disorder. The one-dimensional model we employ also yields a discontinuous transition to perfect plasticity

  18. Stress corrosion cracking lifetime prediction of spring screw

    International Nuclear Information System (INIS)

    Koh, S. K.; Ryu, C. H.

    2004-01-01

    A lifetime prediction of holddown spring screw in nuclear fuel assembly was performed using fracture mechanics approach. The spring screw was designed such that it was capable of sustaining the loads imposed by the initial tensile preload and operational loads. In order to investigate the cause of failure and to predict the stress corrosion cracking life of the screw, a stress analysis of the top nozzle spring assembly was done using finite element analysis. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Normalized stress intensity factors for PWSCC life prediction was proposed. Primary water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of the Scott model and resulted in 1.78 years, which was fairly close to the actual service life of the holddown spring screw

  19. Investigation of Tolerance, Yield and Yield Components of Wheat Cultivars to Salinity of Irrigation Water at Sensitive Stages of Growth

    Directory of Open Access Journals (Sweden)

    B Saadatian

    2013-04-01

    Full Text Available This research in order to study of tolerance ability of wheat cultivates yield and yield components to salinity of irrigation water at sensitive stages of growth, was carried out as a factorial based on a randomized complete block design with 3 replications at greenhouse of Agricultural Faculty of Bu-Ali Sina University, in 2009. Treatments were included wheat cultivars of Alvand, Tous, Sayson and Navid and salinity of irrigation water induced by sodium chloride at five levels of 0, 4, 8, 12 and 16 dS m-1. The results showed that percentage and rate of emergence, plant height, 1000-grain weight, number of seed per spike, number of spike per pot, biological and grain yield reduced by increasing salinity level. At all stress levels Navid cv. had highest emergence percentage. In non-stress and 4 dS m-1, Alvand cv. and at higher levels of stress, Tous cv. had high height in reproductive phase. At control and 4 dS m-1, Sayson cv. and at 8, 12 and 16 dS m-1, Tous cv. in majority of yield and yield components traits had significant superior than other cultivars. Tolerance index of Sayson cv. at 4 and 8 dS m-1 was more than other cultivars but at 12 and 16 dS m-1, maximum value of this index was belonged to Tous cv. At all salinity levels, Alvand cv. had least tolerance index to stress. Number of spike per pot had maximum direct effect on grain yield of wheat cultivars in stress condition. Also indirect effect of biological yield via number of spike per pot than other its indirect effects, had maximum share in wheat seed yield.

  20. Recycling of fresh concrete exceeding and wash water in concrete mixing plants

    Directory of Open Access Journals (Sweden)

    Férriz Papí, J. A.

    2014-03-01

    Full Text Available The exceeding concrete and washing equipment water are a matter to solve in concrete production. This paper explains several possibilities for recycling and analyses the products obtained with one recycling equipment. The objective of this work is to study the possibility to increase the percentage of recycling in new mixes. The developed study relates wash water density and fine particles content. Besides, mortar and concrete samples were tested introducing different quantities of these fine particles, substituting cement, sand or only as an addition. Consistency, compressive strength, setting time, absorption, and capillarity were tested. The results indicated an improvement of the studied properties in some percentages when substituting sand. It confirms the possibility to introduce larger quantities of wash water in new concrete mixes, with corrections in sand quantity depending on water density.Los hormigones frescos sobrantes y aguas procedentes de la limpieza de equipos son un inconveniente a resolver en las plantas de hormigón. Este artículo explica varias posibilidades de reciclado y analiza los productos obtenidos en un equipo reciclador concreto, con el objetivo de estudiar el incremento del porcentaje de reciclaje en nuevas amasadas. El estudio realizado relaciona la densidad del agua de lavado y el contenido de partículas finas. Además, ensaya muestras de mortero y hormigón realizando sustituciones de estas partículas finas por cemento, arena o simplemente como adición. Determina consistencia, resistencia a compresión, principio y fin de fraguado, absorción y capilaridad. Los resultados indicaron un incremento general de las propiedades estudiadas en algunos porcentajes de sustitución por arena. Ello confirma la posibilidad de introducir mayores cantidades de agua de lavado en nuevas amasadas de hormigón, mediante correcciones en la dosificación de arena en función de la densidad del agua.

  1. Predicted and observed therapeutic dose exceedances of ionizable pharmaceuticals in fish plasma from urban coastal systems.

    Science.gov (United States)

    Scott, W Casan; Du, Bowen; Haddad, Samuel P; Breed, Christopher S; Saari, Gavin N; Kelly, Martin; Broach, Linda; Chambliss, C Kevin; Brooks, Bryan W

    2016-04-01

    Instream flows of the rapidly urbanizing watersheds and estuaries of the Gulf of Mexico in Texas (USA) are increasingly dominated by reclaimed waters. Though ionizable pharmaceuticals have received increasing attention in freshwaters, many research questions remain unanswered, particularly in tidally influenced urban coastal systems, which experience significant spatiotemporal variability in pH that influences bioavailability and bioaccumulation. The authors coupled fish plasma modeling of therapeutic hazard values with field monitoring of water chemistry variability and pharmaceutical occurrence to examine whether therapeutic hazards to fish existed within these urban coastal ecosystems and whether therapeutic hazards differed within and among coastal locations and seasons. Spatial and temporal fluctuations in pH within study sites altered the probability of encountering pharmaceutical hazards to fish. Significant water quality differences were consistently observed among traditional parameters and pharmaceuticals collected from surface and bottom waters, which are rarely sampled during routine surface water quality assessments. The authors then compared modeling predictions of fish plasma concentrations of pharmaceuticals to measured plasma levels from various field-collected fish species. Diphenhydramine and diltiazem were observed in plasma of multiple species, and diltiazem exceeded human therapeutic doses in largemouth bass, catfish, and mullet inhabiting these urban estuaries. Though the present study only examined a small number of target analytes, which represent a microcosm of the exposome of these fish, coastal systems are anticipated to be more strongly influenced by continued urbanization, altered instream flows, and population growth in the future. Unfortunately, aquatic toxicology information for diltiazem and many other pharmaceuticals is not available for marine and estuarine organisms, but such field observations suggest that potential adverse

  2. Physically based probability criterion for exceeding radionuclide concentration limits in heterogeneous bedrock

    International Nuclear Information System (INIS)

    Worman, A.; Xu, S.; Dverstorp, B.

    2004-01-01

    A significant problem in a risk analysis of the repository for high-level nuclear waste is to estimate the barrier effect of the geosphere. The significant spatial variability of the rock properties implies that migrating RNs encounter a distribution of bedrock properties and mass-transfer mechanisms in different proportions along the transport paths. For practical reasons, we will never be able to know exactly this distribution of properties by performing a reasonable amount of measurements in a site investigation. On the contrary, recent experimental studies reveal that crystalline bedrock can possess a marked heterogeneity of various physical and geochemical properties that potentially may have a certain impact on the transport of RNs in fractured bedrock. Also current field investigation techniques provide only fragmentary information of the properties of the geosphere. This is a basic motivation for treating flows of water and solute elements in groundwaters by means of stochastic continuum models. The stochastic analysis is based on the idea that we know only certain point values of the property fields and use this information to estimate intermediate values. The probabilistic properties of the stochastic analysis are suitable input variables for risk analyses of the relevant sequence of extreme events for which empirical observations are rare or non-existing. The purpose of this paper is to outline the implications of the stochastic approach for estimating probabilities that certain concentration limits are exceeded at discharge points from. the bedrock in case of a leakage from the waste repository. The analysis is restricted to the water flow and solute transport in the bedrock alone without consideration of the full sequence of events in a full risk analysis and the Bayesian statistics involved in such conditioned (and cross-correlated) event series. The focus is on the implication for the risk analysis of the auto-covariance structure in bedrock

  3. Investigations on evaluation method for yield strength of round bar undermatched joint

    International Nuclear Information System (INIS)

    Matsumoto, Toshimi; Satoh, Hiroshi; Wadayama, Yoshihide

    1988-01-01

    The objective values of the yield strength and fracture toughness are respectively more than 1200 MPa and 200 MPa √m at 4K on the structural material for the superconducting magnet container in the Fusion Reactor. It should be desirable to assure the above value for the properties of the weld metal used for the containers. The initial yielding behavior of the undermatched joint is investigated in this paper. Results are as follows. (1) On the nominal stress vs. nominal strain relationship at the central section of the undermatched metal of the joint, the stress increases higher than the yield stress of undermatched metal itself then gradually comes up to a constant value, after the whole area of the undermatched metal starts to generate plastic deformation as the stress reaches the yield stress of the metal. (2) The increase in the stress is caused by the restraint effect of the base metal on the plasticity, and the stress becomes larger with the larger strength ratio of the undermatched metal to the basemetal and with the smaller relative thickness of the joint. (3) The strain does not distribute uniformly at the central section of the undermatched metal along the radial direction during the initial yielding process of the joint. (4) In the case that the yield strength of the joints is considered as the proof stress desided for a constant offset strain, the relationship between the dimensionless yield strength of the joint to the yield stress of the base metal and the relative yield strength of the undermatched metal to the base metal cannot be not established consistently. (5) The assumption that the base metal is rigid, causes the excessive evaluation of the joint yield strength of theoretical analysis. (6) As the quantitative evaluation method, the stress vs. strain relationship and then the algebraic expression has been formulated for the initial yielding behavior of the joint. (author)

  4. Stress corrosion cracking mitigation by ultrasound induced cavitation technique

    Energy Technology Data Exchange (ETDEWEB)

    Fong, C.; Lee, Y.C. [Industrial Technology Research Inst., Taiwan (China); Yeh, T.K. [National Tsing Hua Univ., Taiwan (China)

    2014-07-01

    Cavitation is usually considered as a damaging mechanism under erosion corrosion condition. However, if used appropriately, cavitation can be applied as a peening technique for surface stress modification process. The aim of surface stress modification is to alter the stress state of processed surface through direct or indirect thermo-mechanical treatments to reduce cracking problems initiated from surface. Ultrasonic devices are used to generate cavitation bubbles which when collapse will produce high intensity shock waves and high velocity micro-jet streams. The cavitation impact when properly controlled will create plastically deformed compressive layers in nearby surfaces and minimize cracking susceptibility in corrosive environments. This study is to investigate the effectiveness of Ultrasound Induced Cavitation (UIC) technique in surface stress improvement. Ultrasonic cavitation treatment of SS304 stainless steel under pure water is carried out with different controlling parameters. The cavitation impact on SS304 surface is measured in terms of surface roughness, surface strain, hardness, and microstructural characteristics. The in-depth residual stress distribution and crack mitigation effect are also evaluated. Test result indicates ultrasound induced cavitation treatment only has minor effect on surface physical characteristics. The extent of compressive stress produced on top surface exceeds the yield strength and can reach a depth above 150 μm. The maximum surface strain measured is generally below 20%, which is not considered detrimental to accelerate crack initiation. Stress corrosion verification tests show UIC treatment is capable in preventing environmental assisted cracking of stainless steels in severely corrosive conditions. In view of the test results, UIC technique has demonstrated to be a low cost, low contaminating, and effective surface stress improvement technology. (author)

  5. Stress corrosion cracking mitigation by ultrasound induced cavitation technique

    International Nuclear Information System (INIS)

    Fong, C.; Lee, Y.C.; Yeh, T.K.

    2014-01-01

    Cavitation is usually considered as a damaging mechanism under erosion corrosion condition. However, if used appropriately, cavitation can be applied as a peening technique for surface stress modification process. The aim of surface stress modification is to alter the stress state of processed surface through direct or indirect thermo-mechanical treatments to reduce cracking problems initiated from surface. Ultrasonic devices are used to generate cavitation bubbles which when collapse will produce high intensity shock waves and high velocity micro-jet streams. The cavitation impact when properly controlled will create plastically deformed compressive layers in nearby surfaces and minimize cracking susceptibility in corrosive environments. This study is to investigate the effectiveness of Ultrasound Induced Cavitation (UIC) technique in surface stress improvement. Ultrasonic cavitation treatment of SS304 stainless steel under pure water is carried out with different controlling parameters. The cavitation impact on SS304 surface is measured in terms of surface roughness, surface strain, hardness, and microstructural characteristics. The in-depth residual stress distribution and crack mitigation effect are also evaluated. Test result indicates ultrasound induced cavitation treatment only has minor effect on surface physical characteristics. The extent of compressive stress produced on top surface exceeds the yield strength and can reach a depth above 150 μm. The maximum surface strain measured is generally below 20%, which is not considered detrimental to accelerate crack initiation. Stress corrosion verification tests show UIC treatment is capable in preventing environmental assisted cracking of stainless steels in severely corrosive conditions. In view of the test results, UIC technique has demonstrated to be a low cost, low contaminating, and effective surface stress improvement technology. (author)

  6. Consumo, produção de leite e estresse térmico em vacas da raça Pardo-Suíça alimentadas com castanha de caju Dry mater intake, milk yield, and heat stress indicators of dairy cows fed diets with cashew nut

    Directory of Open Access Journals (Sweden)

    P.G. Pimentel

    2007-12-01

    Full Text Available Avaliaram-se o consumo de matéria seca, a produção de leite e os indicadores de estresse térmico de vacas Pardo-Suíça alimentadas com castanha de caju no semi-árido do Nordeste do Brasil. Doze animais foram distribuídos em um ensaio de reversão, com quatro tratamentos: 0, 8, 16 e 24% de castanha no concentrado. As vacas receberam cana-de-açúcar à vontade e sete quilos de concentrado por dia. Maior consumo de matéria seca de cana-de-açúcar foi observado no tratamento com concentrado sem castanha (7,70kgMS/dia em relação aos tratamentos com 16% e 24% de castanha (7,35 e 7,05kgMS/dia, respectivamente. O consumo no tratamento com concentrado sem castanha não diferiu do consumo no tratamento com 8% (7,59kgMS/dia. Não houve efeito dos tratamentos sobre a produção de leite e sobre as variáveis indicativas de estresse térmico (P>0,05.A study was carried out to evaluate dry matter intake, milk yield, and heat stress parameters in Brown Swiss cows fed diets with cashew nut. Animals were raised in the semi-arid region of the Brazilian Northeast. Twelve cows were subjected to a switch back experimental design, with four treatments: 0, 8, 16, and 24% of cashew nut in the concentrate. Each cow received 7kg of concentrate per day and had free access to sugar cane. Dry matter (DM intake and milk yield were daily taken as well as measurements of rectal and milk temperature; and cardiac and respiratory rates. The highest intake of forage (sugar cane was obtained when the concentrate had no cashew nut (7.7kgDM/day. This value was not different when the concentrate contained 8% of cashew nut (7.59kgDM/day but greater than dry matter intake of cows receiving diets with 16% of cashew nut (7.35kgDM/day; P0.05. Such low variability in daily milk yield could be associated with the higher energy density of diets containing more cashew nut. Finally, indicators of heat stress were not influenced by changes in the diets, given the air temperatures and

  7. Rapidly star-forming galaxies adjacent to quasars at redshifts exceeding 6.

    Science.gov (United States)

    Decarli, R; Walter, F; Venemans, B P; Bañados, E; Bertoldi, F; Carilli, C; Fan, X; Farina, E P; Mazzucchelli, C; Riechers, D; Rix, H-W; Strauss, M A; Wang, R; Yang, Y

    2017-05-24

    The existence of massive (10 11 solar masses) elliptical galaxies by redshift z ≈ 4 (refs 1, 2, 3; when the Universe was 1.5 billion years old) necessitates the presence of galaxies with star-formation rates exceeding 100 solar masses per year at z > 6 (corresponding to an age of the Universe of less than 1 billion years). Surveys have discovered hundreds of galaxies at these early cosmic epochs, but their star-formation rates are more than an order of magnitude lower. The only known galaxies with very high star-formation rates at z > 6 are, with one exception, the host galaxies of quasars, but these galaxies also host accreting supermassive (more than 10 9 solar masses) black holes, which probably affect the properties of the galaxies. Here we report observations of an emission line of singly ionized carbon ([C ii] at a wavelength of 158 micrometres) in four galaxies at z > 6 that are companions of quasars, with velocity offsets of less than 600 kilometres per second and linear offsets of less than 100 kiloparsecs. The discovery of these four galaxies was serendipitous; they are close to their companion quasars and appear bright in the far-infrared. On the basis of the [C ii] measurements, we estimate star-formation rates in the companions of more than 100 solar masses per year. These sources are similar to the host galaxies of the quasars in [C ii] brightness, linewidth and implied dynamical mass, but do not show evidence for accreting supermassive black holes. Similar systems have previously been found at lower redshift. We find such close companions in four out of the twenty-five z > 6 quasars surveyed, a fraction that needs to be accounted for in simulations. If they are representative of the bright end of the [C ii] luminosity function, then they can account for the population of massive elliptical galaxies at z ≈ 4 in terms of the density of cosmic space.

  8. Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities

    Science.gov (United States)

    Asquith, William H.; Kiang, Julie E.; Cohn, Timothy A.

    2017-07-17

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Nuclear Regulatory Commission, has investigated statistical methods for probabilistic flood hazard assessment to provide guidance on very low annual exceedance probability (AEP) estimation of peak-streamflow frequency and the quantification of corresponding uncertainties using streamgage-specific data. The term “very low AEP” implies exceptionally rare events defined as those having AEPs less than about 0.001 (or 1 × 10–3 in scientific notation or for brevity 10–3). Such low AEPs are of great interest to those involved with peak-streamflow frequency analyses for critical infrastructure, such as nuclear power plants. Flood frequency analyses at streamgages are most commonly based on annual instantaneous peak streamflow data and a probability distribution fit to these data. The fitted distribution provides a means to extrapolate to very low AEPs. Within the United States, the Pearson type III probability distribution, when fit to the base-10 logarithms of streamflow, is widely used, but other distribution choices exist. The USGS-PeakFQ software, implementing the Pearson type III within the Federal agency guidelines of Bulletin 17B (method of moments) and updates to the expected moments algorithm (EMA), was specially adapted for an “Extended Output” user option to provide estimates at selected AEPs from 10–3 to 10–6. Parameter estimation methods, in addition to product moments and EMA, include L-moments, maximum likelihood, and maximum product of spacings (maximum spacing estimation). This study comprehensively investigates multiple distributions and parameter estimation methods for two USGS streamgages (01400500 Raritan River at Manville, New Jersey, and 01638500 Potomac River at Point of Rocks, Maryland). The results of this study specifically involve the four methods for parameter estimation and up to nine probability distributions, including the generalized extreme value, generalized

  9. Radial and azimuthal distribution of Io's oxygen neutral cloud observed by Hisaki/EXCEED

    Science.gov (United States)

    Koga, R.; Tsuchiya, F.; Kagitani, M.; Sakanoi, T.; Yoneda, M.; Yoshikawa, I.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kimura, T.; Smith, H. T.

    2017-12-01

    We report the spatial distributions of oxygen neural cloud surrounding Jupiter's moon Io and along Io's orbit observed by the HISAKI satellite. Atomic oxygen and sulfur in Io's atmosphere escape from the exobase and move to corona ( 5.8 Io radii) mainly due to atmospheric sputtering. Io plasma torus is formed by ionization of these atoms by electron impact and charge exchange processes. It is essential to examine the dominant source of Io plasma torus, particularly in the vicinity of Io (5.8 Io radii; extended neutral clouds). The spatial distribution of oxygen and sulfur neutral clouds is important to understand the source. The extreme ultraviolet spectrometer called EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) installed on the Hisaki satellite observed Io plasma torus continuously in 2014-2015, and we carried out the monitoring of the distribution of atomic oxygen emission at 130.4 nm. The emission averaged over the distance range of 4.5-6.5 Jovian radii on the dawn and dusk sides strongly depends on the Io phase angle (IPA), and has a emission peak between IPA of 60-90 degrees on the dawn side, and between 240-270 degrees on the dusk side, respectively. It also shows the asymmetry with respect to Io's position: the intensity averaged for IPA 60-90 degrees (13.3 Rayleighs (R)) is 1.2 times greater than that for IPA 90-120 degrees (11.1 R) on the dawn side. The similar tendency is found on the dusk side. Weak atomic oxygen emission (4 R) uniformly distributes in every IPA. We also examined the radial distribution of the oxygen neutral cloud during the same period and found the emission peak near Io's orbit with decreasing the intensity toward 8.0 Jupiter radii. The results show the high density component of the oxygen neutral cloud is concentrated around Io and extends mainly toward leading side of Io. In addition, the low density neutrals uniformly exist along Io's orbit. Both components extend radially outward up to 8 Jovian radii with

  10. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  11. VARIABILITY OF YIELD AND YIELD COMPONENTS IN “EGUSI ...

    African Journals Online (AJOL)

    journal

    Estimate of expected genetic advance in seed yield plant-1 ranged between. 25.90-48.40%. ..... values in fruit and seed yield characters have been reported in culinary melon, ... and Khund, A. 2004. Extent of heterosis and heritability in some.

  12. Response of Yield and Yield Components of Tef [Eragrostis Tef ...

    African Journals Online (AJOL)

    The partial budget analysis also indicates that applications of 46 kg. N ha-1 and 10 kg P ha-1 are ..... (1994) indicated that where the grain yield response is negative, yield reduction is primarily caused by a .... An Economic Training. Manual.

  13. On yield gaps and yield gains in intercropping

    NARCIS (Netherlands)

    Gou, Fang; Yin, Wen; Hong, Yu; Werf, van der Wopke; Chai, Qiang; Heerink, Nico; Ittersum, van Martin K.

    2017-01-01

    Wheat-maize relay intercropping has been widely used by farmers in northwest China, and based on field experiments agronomists report it has a higher productivity than sole crops. However, the yields from farmers’ fields have not been investigated yet. Yield gap analysis provides a framework to

  14. 7755 EFFECT OF NPK FERTILIZER ON FRUIT YIELD AND YIELD ...

    African Journals Online (AJOL)

    Win7Ent

    2013-06-03

    Jun 3, 2013 ... peasant farmers in Nigeria. With the increased ... did not significantly (p=0.05) increase the fruit yield nor the seed yield. Key words: NPK fertilizer, Fruit ..... SAS (Statistical Analysis System) Version 9.1. SAS Institute Inc., Cary, ...

  15. SLIFER measurement for explosive yield

    International Nuclear Information System (INIS)

    Bass, R.C.; Benjamin, B.C.; Miller, H.M.; Breding, D.R.

    1976-04-01

    This report describes the shorted location indicator by frequency of electrical resonance (SLIFER) system used at Sandia Laboratories for determination of explosive yield of under ground nuclear tests

  16. Increasing crop diversity mitigates weather variations and improves yield stability.

    Science.gov (United States)

    Gaudin, Amélie C M; Tolhurst, Tor N; Ker, Alan P; Janovicek, Ken; Tortora, Cristina; Martin, Ralph C; Deen, William

    2015-01-01

    Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental

  17. Yield surfaces for perforated plates with square arrays of holes

    International Nuclear Information System (INIS)

    Bhattacharya, A.; Venkat Raj, V.

    2004-01-01

    A symmetric model of a perforated plate containing a 3x3 array of circular holes, arranged in a square pattern, was chosen and elastoplastic finite element analyses were carried out to determine the limit stresses for both pitch and diagonal directions of loading, for different values of biaxiality ratios. Plane stress conditions were assumed and the Tresca and von Mises yield criteria were employed to obtain two different sets of results. Yield surfaces were constructed and 'general cut-out factors' were determined for four different ligament efficiencies. The FEM results obtained by the authors using the Tresca and von Mises yield criteria were compared with the corresponding results of [J. Pressure Vessel Technol. Trans. ASME (1975) 146-154] and [J. Pressure Vessel Technol. Trans. ASME (1997) 122-126], respectively. The results based on the Tresca yield criterion obtained by the present authors and those in [J. Pressure Vessel Technol. Trans. ASME (1975) 146-154] were found to agree well with each other. In the case of the von Mises yield criterion, the agreement with [J. Pressure Vessel Technol. Trans. ASME 122-126] is generally good. The estimates based on the Tresca yield criterion are seen to result in lower values of limit stresses and cut-out factors as compared to those based on the von Mises yield criterion. The difference is attributed to the yield criterion and the flow rule chosen for the analysis. The shape as well as the size of the yield surface was found to depend on the ligament efficiency

  18. Estimation of peak discharge quantiles for selected annual exceedance probabilities in northeastern Illinois

    Science.gov (United States)

    Over, Thomas M.; Saito, Riki J.; Veilleux, Andrea G.; Sharpe, Jennifer B.; Soong, David T.; Ishii, Audrey L.

    2016-06-28

    This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of equations was developed through a temporal analysis with a two-step least squares-quantile regression technique that measures the average effect of changes in the urbanization of the watersheds used in the study. The resulting equations can be used to adjust rural peak discharge quantiles for the effect of urbanization, and in this study the equations also were used to adjust the annual maximum peak discharges from the study watersheds to 2010 urbanization conditions.The other set of equations was developed by a spatial analysis. This analysis used generalized least-squares regression to fit the peak discharge quantiles computed from the urbanization-adjusted annual maximum peak discharges from the study watersheds to drainage-basin characteristics. The peak discharge quantiles were computed by using the Expected Moments Algorithm following the removal of potentially influential low floods defined by a multiple Grubbs-Beck test. To improve the quantile estimates, regional skew coefficients were obtained from a newly developed regional skew model in which the skew increases with the urbanized land use fraction. The drainage-basin characteristics used as explanatory variables in the spatial analysis include drainage area, the fraction of developed land, the fraction of land with poorly drained soils or likely water, and the basin slope estimated as the ratio of the basin relief to basin perimeter.This report also provides the following: (1) examples to illustrate the use of the spatial and urbanization-adjustment equations for estimating peak discharge quantiles at ungaged

  19. Magnitude of flood flows for selected annual exceedance probabilities for streams in Massachusetts

    Science.gov (United States)

    Zarriello, Phillip J.

    2017-05-11

    The U.S. Geological Survey, in cooperation with the Massachusetts Department of Transportation, determined the magnitude of flood flows at selected annual exceedance prob­abilities (AEPs) at streamgages in Massachusetts and from these data developed equations for estimating flood flows at ungaged locations in the State. Flood magnitudes were deter­mined for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs at 220 streamgages, 125 of which are in Massachusetts and 95 are in the adjacent States of Connecticut, New Hamp­shire, New York, Rhode Island, and Vermont. AEP flood flows were computed for streamgages using the expected moments algorithm weighted with a recently computed regional skew­ness coefficient for New England.Regional regression equations were developed to estimate the magnitude of floods for selected AEP flows at ungaged sites from 199 selected streamgages and for 60 potential explanatory basin characteristics. AEP flows for 21 of the 125 streamgages in Massachusetts were not used in the final regional regression analysis, primarily because of regulation or redundancy. The final regression equations used general­ized least squares methods to account for streamgage record length and correlation. Drainage area, mean basin elevation, and basin storage explained 86 to 93 percent of the variance in flood magnitude from the 50- to 0.2-percent AEPs, respec­tively. The estimates of AEP flows at streamgages can be improved by using a weighted estimate that is based on the magnitude of the flood and associated uncertainty from the at-site analysis and the regional regression equations. Weighting procedures for estimating AEP flows at an ungaged site on a gaged stream also are provided that improve estimates of flood flows at the ungaged site when hydrologic characteristics do not abruptly change.Urbanization expressed as the percentage of imperviousness provided some explanatory power in the regional regression; however, it was not statistically

  20. Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

    Science.gov (United States)

    Zarriello, Phillip J.; Ahearn, Elizabeth A.; Levin, Sara B.

    2012-01-01

    Heavy persistent rains from late February through March 2010 caused severe widespread flooding in Rhode Island that set or nearly set record flows and water levels at many long-term streamgages in the State. In response, the U.S. Geological Survey, in partnership with the Federal Emergency Management Agency, conducted a study to update estimates of flood magnitudes at streamgages and regional equations for estimating flood flows at ungaged locations. This report provides information needed for flood plain management, transportation infrastructure design, flood insurance studies, and other purposes that can help minimize future flood damages and risks. The magnitudes of floods were determined from the annual peak flows at 43 streamgages in Rhode Island (20 sites), Connecticut (14 sites), and Massachusetts (9 sites) using the standard Bulletin 17B log-Pearson type III method and a modification of this method called the expected moments algorithm (EMA) for 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probability (AEP) floods. Annual-peak flows were analyzed for the period of record through the 2010 water year; however, records were extended at 23 streamgages using the maintenance of variance extension (MOVE) procedure to best represent the longest period possible for determining the generalized skew and flood magnitudes. Generalized least square regression equations were developed from the flood quantiles computed at 41 streamgages (2 streamgages in Rhode Island with reported flood quantiles were not used in the regional regression because of regulation or redundancy) and their respective basin characteristics to estimate magnitude of floods at ungaged sites. Of 55 basin characteristics evaluated as potential explanatory variables, 3 were statistically significant—drainage area, stream density, and basin storage. The pseudo-coefficient of determination (pseudo-R2) indicates these three explanatory variables explain 95 to 96 percent of the variance

  1. Prediction of yield and long-term failure of oriented polypropylene: kinetics and anisotropy

    NARCIS (Netherlands)

    van Erp, T.B.; Reynolds, C.T.; Peijs, T.; van Dommelen, J.A.W.; Govaert, L.E.

    2009-01-01

    The time-dependent yield and failure behavior of off-axis loaded uniaxially oriented polypropy-lene tape is investigated. The yield and failure behavior is described with an anisotropic vis-coplastic model. A viscoplastic flow rule is used with an equivalent stress, based on Hill’sanisotropic yield

  2. Stress Management: Job Stress

    Science.gov (United States)

    Healthy Lifestyle Stress management Job stress can be all-consuming — but it doesn't have to be. Address your triggers, keep perspective and ... stress triggers, it's often helpful to improve time management skills — especially if you tend to feel overwhelmed ...

  3. Breeding for Grass Seed Yield

    DEFF Research Database (Denmark)

    Boelt, Birte; Studer, Bruno

    2010-01-01

    Seed yield is a trait of major interest for many fodder and amenity grass species and has received increasing attention since seed multiplication is economically relevant for novel grass cultivars to compete in the commercial market. Although seed yield is a complex trait and affected...... by agricultural practices as well as environmental factors, traits related to seed production reveal considerable genetic variation, prerequisite for improvement by direct or indirect selection. This chapter first reports on the biological and physiological basics of the grass reproduction system, then highlights...... important aspects and components affecting the seed yield potential and the agronomic and environmental aspects affecting the utilization and realization of the seed yield potential. Finally, it discusses the potential of plant breeding to sustainably improve total seed yield in fodder and amenity grasses....

  4. Childhood Stress

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Childhood Stress KidsHealth / For Parents / Childhood Stress What's in this ... and feel stress to some degree. Sources of Stress Stress is a function of the demands placed ...

  5. Are GM Crops for Yield and Resilience Possible?

    Science.gov (United States)

    Paul, Matthew J; Nuccio, Michael L; Basu, Shib Sankar

    2018-01-01

    Crop yield improvements need to accelerate to avoid future food insecurity. Outside Europe, genetically modified (GM) crops for herbicide- and insect-resistance have been transformative in agriculture; other traits have also come to market. However, GM of yield potential and stress resilience has yet to impact on food security. Genes have been identified for yield such as grain number, size, leaf growth, resource allocation, and signaling for drought tolerance, but there is only one commercialized drought-tolerant GM variety. For GM and genome editing to impact on yield and resilience there is a need to understand yield-determining processes in a cell and developmental context combined with evaluation in the grower environment. We highlight a sugar signaling mechanism as a paradigm for this approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Yield response of cotton, maize, soybean, sugar beet, sunflower and wheat to deficit irrigation

    International Nuclear Information System (INIS)

    Kirda, C.; Kanber, R.; Tulucu, K.

    1995-01-01

    Results of several field experiments on deficit irrigation programmes in Turkey are discussed. Deficit irrigation of sugar beet with water stress imposed (i e.,irrigation omitted)during ripening,stage saved nearly 22 % water, yet with no significant yield decrease. An experiment, conducted in Turkey Region, the European part of Turkey,and aimed at studying water production functions of sunflower(i e,yield vs water consumption), revealed that water stress imposed at either head forming or seed filling stags influence yield the least , and 40 % savings of irrigation water supply , compared with traditional practices in the region, can be achieved without significant yield reduction. Water stress imposed at vegetative and flowering stages of maize hindered the yield most significantly. The results showed that deficit irrigation can be a feasible option under limited supply of irrigation if stress occurs during yield formation stage. A four year field experiments aiming at developing deficit irrigation strategies for soybean showed that soybean was at the most sensitive to water stress during flowering and pod filling stages, and irrigation during these stages would ensure high yields. Results of experiments on cotton showed that irrigations omitted during yield formation stage did not significantly hinder the yield. Similarly wheat give good yield response if irrigated at booting,heading and milking stages, depending on w heather conditions. In areas where rainfall at planting is limited, supplementary irrigation during this period can ensure good establishment of wheat crop. 1 tab; 9 figs; 59 refs (Author)

  7. Nitrogen rate and plant population effects on yield and yield ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Gan et al., 2003). Nitrogen increases yield by influencing a variety of agronomic and quality parameters. In general, there was an increase in plant height and dry matter accumulation per plant in soybean (Manral and Saxena, ...

  8. Nitrogen rate and plant population effects on yield and yield ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... density and nitrogen rate increased plant height, lowest pod height, harvest index and seed yield. ... since some combine harvester heads are unable to pick ..... as effected by population density and plant distribution.

  9. Yield stress distribution in injection-moulded glassy polymers

    NARCIS (Netherlands)

    Verbeeten, W.M.H.; Kanters, M.J.W.; Engels, T.A.P.; Govaert, L.E.

    2015-01-01

    A methodology for structural analysis simulations is presented that incorporates the distribution of mechanical propertiesalong the geometrical dimensions of injection-moulded amorphous polymer products. It is based on a previously developedmodelling approach, where the thermomechanical history

  10. On the residual yield stress of shocked metals

    International Nuclear Information System (INIS)

    Chapman, David J; Eakins, Daniel E; Proud, William G; Savinykh, Andrey S; Garkushin, Gennady V; Razorenov, Sergey V; Kanel, Gennady I

    2014-01-01

    Precise measurement of the free-surface velocity can be a rich source of information on the effects of time and strain on material strength. With this objective, we performed a careful comparative measurement of the free-surface velocity of shock loaded aluminium AD1 and magnesium alloy Ma2 samples of various thicknesses in the range 0.2 mm to 5 mm. We observed the expected decay in the elastic precursor state with increasing sample thickness for both aluminium and magnesium alloy. However, we also observed a small change in the magnitude of hysteresis in the elastic-plastic compression-unloading cycle; where qualitatively the peak free-surface velocity also increased with increasing specimen thickness. Interestingly, the observed change in hysteresis as function of specimen thickness for the Ma2 alloy was relatively smaller than the AD1, in contrast with the larger change in precursor magnitude observed for the magnesium. We propose that softening due to multiplication of dislocations is relatively large in Ma2 and results in a smaller hysteresis in the elastic-plastic cycle.

  11. Effects of application boron on yields, yield component and oil ...

    African Journals Online (AJOL)

    The study was conducted to investigate the effects of five boron (B) doses; 0, 2.5, 5.0, 7.5 and 10.0 kg B ha-1 in B-deficient calcareous soils on yield and some yield components of four sunflower genotypes. Genotypes have shown variations with respect to their responses to B applications. AS-615 and Coban had the ...

  12. The Cumulative Daily Tolerance Levels of Potentially Toxic Excipients Ethanol and Propylene Glycol Are Commonly Exceeded in Neonates and Infants

    DEFF Research Database (Denmark)

    Valeur, Kristine Svinning; Hertel, Steen Axel; Lundstrøm, Kaare Engell

    2018-01-01

    neonates and infants and compare these levels to the tolerance limits found in guidelines published by European Medicines Agency (EMA). As part of the SEEN study, all medicinal products administered to neonates and infants were recorded. All included neonates received ≥2 medicinal products/day and infants...... ≥3 medicinal products/day. Daily excipient levels were calculated based on quantities obtained from manufacturers or databases. Excipient levels were compared to tolerance limits proposed by the EMA. Altogether, 470 neonates and 160 infants were included, recording 4207 prescriptions and 316 products...... exceed tolerance limit of 6 mg/kg/day. Of the total number of prescriptions involving PG-containing medicinal products (n = 174), 70% would alone exceed a maximum tolerance limit of 50 mg/kg/day. Maximal daily exposure to ethanol (1563 mg/kg/day) or PG (954 mg/kg/day) exceeded the tolerance limits...

  13. Decomposing global crop yield variability

    Science.gov (United States)

    Ben-Ari, Tamara; Makowski, David

    2014-11-01

    Recent food crises have highlighted the need to better understand the between-year variability of agricultural production. Although increasing future production seems necessary, the globalization of commodity markets suggests that the food system would also benefit from enhanced supplies stability through a reduction in the year-to-year variability. Here, we develop an analytical expression decomposing global crop yield interannual variability into three informative components that quantify how evenly are croplands distributed in the world, the proportion of cultivated areas allocated to regions of above or below average variability and the covariation between yields in distinct world regions. This decomposition is used to identify drivers of interannual yield variations for four major crops (i.e., maize, rice, soybean and wheat) over the period 1961-2012. We show that maize production is fairly spread but marked by one prominent region with high levels of crop yield interannual variability (which encompasses the North American corn belt in the USA, and Canada). In contrast, global rice yields have a small variability because, although spatially concentrated, much of the production is located in regions of below-average variability (i.e., South, Eastern and South Eastern Asia). Because of these contrasted land use allocations, an even cultivated land distribution across regions would reduce global maize yield variance, but increase the variance of global yield rice. Intermediate results are obtained for soybean and wheat for which croplands are mainly located in regions with close-to-average variability. At the scale of large world regions, we find that covariances of regional yields have a negligible contribution to global yield variance. The proposed decomposition could be applied at any spatial and time scales, including the yearly time step. By addressing global crop production stability (or lack thereof) our results contribute to the understanding of a key

  14. Small millet farmers increase yields through participatory varietal ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Small millets, despite being rich in micronutrients and dietary fibre and known for their low glycemic index and tolerance of water stress, are in decline in South Asia. Existing varieties suffer from low yield and farmers lack access to improved varieties. The Revalorising Small Millets in Rainfed Regions of South Asia ...

  15. Rock stress investigations

    International Nuclear Information System (INIS)

    Pahl, A.; Heusermann, St.; Braeuer, V.; Gloeggler, W.

    1989-04-01

    On the research project 'Rock Stress Mesurements' the BGR has developed and tested several methods for use in boreholes at a depth of 200 m. Indirect stress measurements using overcoring methods with BGR-probes and CSIR-triaxial cells as well as direct stress measurements using the hydraulic-fracturing method were made. To determine in-situ rock deformation behavior borehole deformation tests, using a BGR-dilatometer, were performed. Two types of the BGR-probe were applied: a four-component-probe to determine horizontal stresses and a five-component-probe to determine a quasi three-dimensional stress field. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on low cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (author) 4 tabs., 76 figs., 31 refs

  16. Genotypic Variation in Yield, Yield Components, Root Morphology and Architecture, in Soybean in Relation to Water and Phosphorus Supply

    Science.gov (United States)

    He, Jin; Jin, Yi; Du, Yan-Lei; Wang, Tao; Turner, Neil C.; Yang, Ru-Ping; Siddique, Kadambot H. M.; Li, Feng-Min

    2017-01-01

    Water shortage and low phosphorus (P) availability limit yields in soybean. Roots play important roles in water-limited and P-deficient environment, but the underlying mechanisms are largely unknown. In this study we determined the responses of four soybean [Glycine max (L.) Merr.] genotypes [Huandsedadou (HD), Bailudou (BLD), Jindou 21 (J21), and Zhonghuang 30 (ZH)] to three P levels [applied 0 (P0), 60 (P60), and 120 (P120) mg P kg-1 dry soil to the upper 0.4 m of the soil profile] and two water treatment [well-watered (WW) and water-stressed (WS)] with special reference to root morphology and architecture, we compared yield and its components, root morphology and root architecture to find out which variety and/or what kind of root architecture had high grain yield under P and drought stress. The results showed that water stress and low P, respectively, significantly reduced grain yield by 60 and 40%, daily water use by 66 and 31%, P accumulation by 40 and 80%, and N accumulation by 39 and 65%. The cultivar ZH with the lowest daily water use had the highest grain yield at P60 and P120 under drought. Increased root length was positively associated with N and P accumulation in both the WW and WS treatments, but not with grain yield under water and P deficits. However, in the WS treatment, high adventitious and lateral root densities were associated with high N and P uptake per unit root length which in turn was significantly and positively associated with grain yield. Our results suggest that (1) genetic variation of grain yield, daily water use, P and N accumulation, and root morphology and architecture were observed among the soybean cultivars and ZH had the best yield performance under P and water limited conditions; (2) water has a major influence on nutrient uptake and grain yield, while additional P supply can modestly increase yields under drought in some soybean genotypes; (3) while conserved water use plays an important role in grain yield under drought

  17. On some features of the effective behaviour of porous solids with J2- and J3-dependent yielding matrix behaviour

    Science.gov (United States)

    Benallal, Ahmed

    2018-02-01

    Some features od the constitutive behaviour of voided materials taking into account possible effects of the Lode angle in the yielding behaviour of the matrix are discussed. The Gurson approach is used to this end. After providing a parametric representation of the effective behaviour of such materials, some closed-form results are given for pure shear stress states and also at very high stress triaxialities. In the former case corresponding to a zero macroscopic mean stress, the contour of the yield domain in the π-plane has exactly the shape of the yield surface of the matrix in the deviatoric plane, but a size reduced by a factor 1 - f, with f the porosity of the voided material. In the latter, effective yield stresses for the voided material are slightly different from the Gurson result and found to be set by the yield stress at a microscopic stress Lode angle π/3 for very high positive triaxiality and by the yield stress at a microscopic stress Lode angle 0 for very high negative triaxiality. This last result is extended for porous materials with yielding depending further on the hydrostatic stress, fully exhibiting the interaction between volumetric and shear interactions on the yielding behaviour of isotropic porous materials. Applications to many usual yielding criteria for the matrix are also provided. xml:lang="fr"

  18. Relação entre a produtividade do mamoeiro e o déficit hídrico (ky na região Norte Fluminense Response coefficient of papaya yield to water stress (ky in Northern Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Robson P. Posse

    2009-04-01

    Full Text Available Teve-se como objetivo neste trabalho, determinar o coeficiente de resposta ao déficit hídrico na produção de frutos comerciais e totais do mamoeiro, cultivado na região Norte do Estado do Rio de Janeiro. O experimento foi realizado na área de convênio UENF/PESAGRO-RIO, no município de Campos dos Goytacazes, RJ, no período de 25/04/2006 a 18/05/2007, utilizando-se o mamoeiro cultivar Híbrido UENF/CALIMAN01 e um delineamento em blocos casualizados, com cinco tratamentos, correspondendo às reposições de 50% (T1, 75% (T2, 100% (T3, 125% (T4 e 150% (T5 da evapotranspiração de referência (ETo, com quatro repetições. A máxima produção comercial real da cultura, aos 13 meses de cultivo e com quatro meses de colheita, foi de 38,78 t ha-1 (T3 e a máxima produção total real encontrada foi de 49,42 t ha-1 (T5. O mamoeiro cultivar Híbrido UENF/CALIMAN01 conduzido até os 13 meses de cultivo e com quatro meses de colheita, apresentou um coeficiente de resposta de produção (ky para frutos comerciais de 1,4581 e para produção total um coeficiente igual a 0,5674.The objective of this study was to determine the response coefficient to water stress in the commercial and total yield of papaya fruits grown in the northern region of the State of Rio de Janeiro. The experiment was conducted in an area of UENF/PESAGRO-RIO in the municipality of Campos dos Goytacazes, Rio de Janeiro, from 25/04/2006 to 18/05/2007, using the papaya cultivar Hybrid UENF/CALIMAN01. The experiment had a randomized block design with five treatments [replacement of reference evapotranspiration (ETo by 50% (T1, 75% (T2, 100% (T3, 125% (T4 and 150% (T5], with four replications. The highest real commercial yield of the crop after 13 months of growth and four harvest months was 38.78 t ha-1 (T3 and the highest total real yield was 49.42 t ha-1 (T5. After 13 months of growth and 4 harvest months of the papaya cultivar Hybrid UENF/CALIMAN01 the response coefficient for

  19. Fission yield measurements at IGISOL

    Science.gov (United States)

    Lantz, M.; Al-Adili, A.; Gorelov, D.; Jokinen, A.; Kolhinen, V. S.; Mattera, A.; Moore, I.; Penttilä, H.; Pomp, S.; Prokofiev, A. V.; Rakopoulos, V.; Rinta-Antila, S.; Simutkin, V.; Solders, A.

    2016-06-01

    The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL) technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f) and Th(p,f) have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn) reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  20. Fission yield measurements at IGISOL

    Directory of Open Access Journals (Sweden)

    Lantz M.

    2016-01-01

    Full Text Available The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f and Th(p,f have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  1. An alternative approach for modeling strength differential effect in sheet metals with symmetric yield functions

    Science.gov (United States)

    Kurukuri, Srihari; Worswick, Michael J.

    2013-12-01

    An alternative approach is proposed to utilize symmetric yield functions for modeling the tension-compression asymmetry commonly observed in hcp materials. In this work, the strength differential (SD) effect is modeled by choosing separate symmetric plane stress yield functions (for example, Barlat Yld 2000-2d) for the tension i.e., in the first quadrant of principal stress space, and compression i.e., third quadrant of principal stress space. In the second and fourth quadrants, the yield locus is constructed by adopting interpolating functions between uniaxial tensile and compressive stress states. In this work, different interpolating functions are chosen and the predictive capability of each approach is discussed. The main advantage of this proposed approach is that the yield locus parameters are deterministic and relatively easy to identify when compared to the Cazacu family of yield functions commonly used for modeling SD effect observed in hcp materials.

  2. The yield drop at or below 423 K in Zr single crystals and in Ti

    International Nuclear Information System (INIS)

    Ferron, A.; Malik, L.M.; Dickson, J.I.

    1979-01-01

    Yield drops were obtained in interrupted tensile and compression tests performed on zirconium single crystals between 262 and 362 K. Near 295 K, where most tests were performed, a minimum yield drop was obtained for an aging performed near the internal stress. For positive stress relaxations and a constant aging time, this yield drop increased linearly with the stress relaxed during aging. This result indicates a significant portion of the yield drop is caused by dislocations gliding to pinning points, which are most probably forest dislocations. A similar behaviour was observed for polycrystalline titanium at 423 K. The yield drops observed in the single crystals at 295 K, after aging at zero stress, increased linearly with the logarithm of the aging time in contrast to the time-independent Haasen-Kelly effect observed in polycrystalline material. (auth)

  3. Investigation of the yield process by deformation luminescence of X-ray irradiated KCl:Ca2+

    International Nuclear Information System (INIS)

    Nakamura, S.; Ida, K.; Ohgaku, T.

    2011-01-01

    It is found that deformation luminescence gives us information about the microscopic yield process of X-ray irradiated KCl:Ca 2+ . The stress-strain curve has a macroscopic yield point. But we find that luminescence appears to start before the macroscopic yield. This means that dislocation begin to move before the macroscopic yield because deformation luminescence is attributed to radiation-induced dislocation motion. The beginning of luminescence is considered to be the microscopic yield. Investigating the dependence of microscopic yield stress on strain rate and impurity concentration gives us additional information. The activation volume obtained from the dependence of microscopic yield stress on strain rate is comparable to the value estimated from the concentration of impurity. Then the dislocation starts to move overcoming impurity-vacancy dipoles as obstacles to dislocation motion. The dislocation density starts to increase at the microscopic yield point and then sharply increases to the macroscopic yield.

  4. Yield and flow properties of aluminum alloy AA 8001

    International Nuclear Information System (INIS)

    Lyons, J.S.; Johnson, H.W.; Han, E.G.

    1995-01-01

    Aluminum alloy AA 8001 is being used at the Westinghouse Savannah River Company (WSRC) for nuclear reactor fuel and target components. The objective of this research was to determine parameters for predictive models of the compressive flow properties of AA 8001. Seventy-five true strain-rate, hot compression tests were performed. New, quantitative information about the yield and flow behavior of aluminum alloy AA 8001 was determined. Parameters were determined to use in a hyperbolic sine constitutive law so that the yield stress, the peak stress, and the peak strain can be predicted from the temperature-compensated strain-rate, Z. It was found that the onset of strain softening was more strongly dependent on Z than the onset of yielding was

  5. Genetic Analysis of Relative Cell Injury Percentage and Some Yield Contributing Traits in Wheat Under Nomral and Heat Stress Conditions Análisis Genético del Porcentaje Relativo de Daño celular y algún Rasgo que Contribuye al Rendimiento en Trigo bajo Condiciones Normales y de Estrés Térmico

    Directory of Open Access Journals (Sweden)

    Jehanzeb Farooq

    2011-12-01

    Full Text Available Several wheat genotypes were screened against heat stress. Seven wheat (Triticum aestivum L. cultivars obtained after screening against heat classified as tolerant, moderately tolerant, and susceptible to heat stress, were mated in a complete diallel mating system to study the inheritance pattern of relative cell injury percentage (cell injury % and some yield contributing parameters under normal and heat stress conditions. Significant genotypic differences were found (P Varios genotipos de trigo se discriminaron para estrés térmico. De ellos siete cultivares de trigo (Triticum aestivum L. incluyendo tolerantes, moderadamente tolerantes, y susceptibles a estrés térmico obtenidos después de discriminar con calor se aparearon en un sistema de apareamiento de dialelo completo para estudiar el patrón de heredabilidad del porcentaje de daño celular relativo (daño celular % y algunos parámetros que contribuyen al rendimiento bajo condiciones normales o de estrés térmico. Se encontraron diferencias genotípicas significativas (P < 0.01 para todos los rasgos estudiados bajo ambas condiciones. Pruebas de ajuste revelaron adecuación parcial para rasgos como días a espigadura y días a madurez en ambas condiciones pero mostraron suficiencia completa para área hoja bandera y daño celular % en ambas condiciones. El modelo para producción de grano por planta y biomasa por planta fue completamente suficiente bajo condiciones normales y completamente adecuado en estrés. El componente aditivo de variación genotípica (D fue significativo para todos los rasgos estudiados y más que los componentes de dominancia H1 y H2. Los valores de la proporción de genes con efectos positivos y negativos en los progenitores (H2/4H1 demostraron distribución desigual de genes dominantes en los progenitores para casi todos los rasgos excepto área de hoja bandera, producción de grano, y daño celular % en ambas condiciones. Se encontraron estimaciones

  6. Projected climate change impacts upon dew yield in the Mediterranean basin

    Energy Technology Data Exchange (ETDEWEB)

    Tomaszkiewicz, M. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Abou Najm, M., E-mail: majdian@aub.edu.lb [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Beysens, D. [Physique et Mecanique des Milieux Heterogenes, UMR 7636 CNRS — ESPCI, Universite Pierre et Marie Curie — Universite Paris Diderot, 10 rue Vauquelin, 75005 Paris (France); Service des Basses Temperatures, CEA-Grenoble & Universite Joseph Fourier, Grenoble (France); OPUR, 60 rue Emeriau, 75015 Paris (France); Alameddine, I. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Bou Zeid, E. [Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08540 (United States); El-Fadel, M. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon)

    2016-10-01

    Water scarcity is increasingly raising the need for non-conventional water resources, particularly in arid and semi-arid regions. In this context, atmospheric moisture can potentially be harvested in the form of dew, which is commonly disregarded from the water budget, although its impact may be significant when compared to rainfall during the dry season. In this study, a dew atlas for the Mediterranean region is presented illustrating dew yields using the yield data collected for the 2013 dry season. The results indicate that cumulative monthly dew yield in the region can exceed 2.8 mm at the end of the dry season and 1.5 mm during the driest months, compared to < 1 mm of rainfall during the same period in some areas. Dew yields were compared with potential evapotranspiration (PET) and actual evapotranspiration (ET) during summer months thus highlighting the role of dew to many native plants in the region. Furthermore, forecasted trends in temperature and relative humidity were used to estimate dew yields under future climatic scenarios. The results showed a 27% decline in dew yield during the critical summer months at the end of the century (2080). - Highlights: • Dew atlas for Mediterranean region is presented. • Cumulative dew yields can exceed 2.8 mm at the end of the dry season. • Dew yields compared with PET and ET show the role of dew to many native plants. • Forecasted trends under future climatic scenarios show a 27% decline in dew yield.

  7. 20 CFR 641.740 - How will the Department determine whether a grantee fails, meets, or exceeds the expected levels...

    Science.gov (United States)

    2010-04-01

    ... determine whether a grantee fails, meets, or exceeds the expected levels of performance for the core indicators and what will be the consequences of failing to meet expected levels of performance? (a) Aggregate... determine if a national grantee has met the expected levels of performance (including any adjustments to...

  8. Modelling the risk of Pb and PAH intervention value exceedance in allotment soils by robust logistic regression

    International Nuclear Information System (INIS)

    Papritz, A.; Reichard, P.U.

    2009-01-01

    Soils of allotments are often contaminated by heavy metals and persistent organic pollutants. In particular, lead (Pb) and polycyclic aromatic hydrocarbons (PAHs) frequently exceed legal intervention values (IVs). Allotments are popular in European countries; cities may own and let several thousand allotment plots. Assessing soil contamination for all the plots would be very costly. Soil contamination in allotments is often linked to gardening practice and historic land use. Hence, we predict the risk of IV exceedance from attributes that characterize the history and management of allotment areas (age, nearby presence of pollutant sources, prior land use). Robust logistic regression analyses of data of Swiss allotments demonstrate that the risk of IV exceedance can be predicted quite precisely without costly soil analyses. Thus, the new method allows screening many allotments at small costs, and it helps to deploy the resources available for soil contamination surveying more efficiently. - The contamination of allotment soils, expressed as frequency of intervention value exceedance, depends on the age and further attributes of the allotments and can be predicted by logistic regression.

  9. Methods for estimating annual exceedance-probability discharges and largest recorded floods for unregulated streams in rural Missouri.

    Science.gov (United States)

    2014-01-01

    Regression analysis techniques were used to develop a : set of equations for rural ungaged stream sites for estimating : discharges with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent : annual exceedance probabilities, which are equivalent to : ann...

  10. 48 CFR 736.602-5 - Short selection process for procurements not to exceed the simplified acquisition threshold.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Short selection process for procurements not to exceed the simplified acquisition threshold. 736.602-5 Section 736.602-5... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 736.602-5 Short...

  11. 48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Short selection processes... ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 636.602-5 Short selection processes for contracts not to exceed the simplified acquisition threshold. The short selection process described in FAR 36...

  12. 48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal... ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Service 436.602-5 Short selection process for contracts not...

  13. 48 CFR 836.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 836.602-5 Section 836.602-5 Federal... AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 836.602-5 Short selection process for...

  14. Susceptibility of forests in the northeastern USA to nitrogen and sulfur deposition: critical load exceedance and forest health

    Science.gov (United States)

    N. Duarte; L.H. Pardo; M.J. Robin-Abbott

    2013-01-01

    The objectives of this study were to assess susceptibility to acidification and nitrogen (N) saturation caused by atmospheric deposition to northeastern US forests, evaluate the benefits and shortcomings of making critical load assessments using regional data, and assess the relationship between expected risk (exceedance) and forest health. We calculated the critical...

  15. Utilization of low- and high-voltage electric equipment at heights exceeding 1000 m above sea level

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, M.M.

    1980-01-01

    The present-day state of high- and low-voltage equipment utilization at heights exceeding 1000 m above sea level is considered with allowance for the technical requirements applicable to the equipment, as provided for in the GOST (All-Union State Standards), and for the results of scientific research studies. 12 refs.

  16. Effect of methyl jasmonate, salicylic acid, Headline and Stadium on root yield, sucrose yield, and storage properties

    Science.gov (United States)

    Methyl jasmonate (MeJA) and salicylic acid (SA) have been reported to enhance yield and protect crop plants and products against abiotic stresses and diseases. The effect of these compounds on sugarbeets, however, is unknown. Research was conducted in 2016 and 2017 to investigate the effects of an e...

  17. Empirical applications of an environmental stress indicator and the environmental efficiency revolution in Taiwan

    Directory of Open Access Journals (Sweden)

    Han-Shen Chen

    2013-09-01

    Full Text Available In this essay, the first aim is to apply the structure of material flow analysis (MFA and ecological footprint model to construct an environmental stress indicator. Secondly, an impact, population, affluence and technology (IPAT analysis is used to resolve indicators related to MFA and resource yield productivity. The research indicates following results: (1 The 2007 per capita ecological deficit in Taiwan is 6.3441 square hm.The figures reflect that productivity and life intensity of residents have exceeded the carrying capacity of Taiwan's ecological economic system. (2 Wealth becomes the most important factor in material needs and pollution discharge. (3 Environmental efficiency and ecological efficiency slowed down dramatically, demonstrating that use of resources and total amount of environmental stress stay at a developmental stage. Therefore, if proper measures are not adopted, the current weak sustainability will lead into the vicious circle which departs from sustainable development.

  18. Competitive ability, stress tolerance and plant interactions along stress gradients.

    Science.gov (United States)

    Qi, Man; Sun, Tao; Xue, SuFeng; Yang, Wei; Shao, DongDong; Martínez-López, Javier

    2018-04-01

    Exceptions to the generality of the stress-gradient hypothesis (SGH) may be reconciled by considering species-specific traits and stress tolerance strategies. Studies have tested stress tolerance and competitive ability in mediating interaction outcomes, but few have incorporated this to predict how species interactions shift between competition and facilitation along stress gradients. We used field surveys, salt tolerance and competition experiments to develop a predictive model interspecific interaction shifts across salinity stress gradients. Field survey and greenhouse tolerance tests revealed tradeoffs between stress tolerance and competitive ability. Modeling showed that along salinity gradients, (1) plant interactions shifted from competition to facilitation at high salinities within the physiological limits of salt-intolerant plants, (2) facilitation collapsed when salinity stress exceeded the physiological tolerance of salt-intolerant plants, and (3) neighbor removal experiments overestimate interspecific facilitation by including intraspecific effects. A community-level field experiment, suggested that (1) species interactions are competitive in benign and, facilitative in harsh condition, but fuzzy under medium environmental stress due to niche differences of species and weak stress amelioration, and (2) the SGH works on strong but not weak stress gradients, so SGH confusion arises when it is applied across questionable stress gradients. Our study clarifies how species interactions vary along stress gradients. Moving forward, focusing on SGH applications rather than exceptions on weak or nonexistent gradients would be most productive. © 2018 by the Ecological Society of America.

  19. Risk of shear failure and extensional failure around over-stressed excavations in brittle rock

    Directory of Open Access Journals (Sweden)

    Nick Barton

    2017-04-01

    Full Text Available The authors investigate the failure modes surrounding over-stressed tunnels in rock. Three lines of investigation are employed: failure in over-stressed three-dimensional (3D models of tunnels bored under 3D stress, failure modes in two-dimensional (2D numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD, both in intact rock and in rock masses with one or two joint sets, and finally, observations in TBM (tunnel boring machine tunnels in hard and medium hard massive rocks. The reason for ‘stress-induced’ failure to initiate, when the assumed maximum tangential stress is approximately (0.4–0.5σc (UCS, uniaxial compressive strength in massive rock, is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect. However, because similar ‘stress/strength’ failure limits are found in mining, nuclear waste research excavations, and deep road tunnels in Norway, one is easily misled into thinking of compressive stress induced failure. Because of this, the empirical SRF (stress reduction factor in the Q-system is set to accelerate as the estimated ratio σθmax/σc >> 0.4. In mining, similar ‘stress/strength’ ratios are used to suggest depth of break-out. The reality behind the fracture initiation stress/strength ratio of ‘0.4’ is actually because of combinations of familiar tensile and compressive strength ratios (such as 10 with Poisson's ratio (say 0.25. We exceed the extensional strain limits and start to see acoustic emission (AE when tangential stress σθ ≈ 0.4σc, due to simple arithmetic. The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by ‘stable’ extensional strain fracturing, but propagation in ‘unstable’ and therefore dynamic shearing. In the case of very deep tunnels (and 3D physical simulations, compressive stresses may be too high for extensional strain fracturing, and

  20. Asymmetric correlation of sovereign bond yield dynamics in the Eurozone

    Directory of Open Access Journals (Sweden)

    Dajcman Silvo

    2013-01-01

    Full Text Available This paper examines the symmetry of correlation of sovereign bond yield dynamics between eight Eurozone countries (Austria, Belgium, France, Germany, Ireland, Italy, Portugal, and Spain in the period from January 3, 2000 to August 31, 2011. Asymmetry of correlation is investigated pair-wise by applying the test of Yongmiao Hong, Jun Tu, and Guofu Zhou (2007. Whereas the test of Hong, Tu, and Zhou (2007 is static, the present paper provides also a dynamic version of the test and identifies time periods when the correlation of Eurozone sovereign bond yield dynamics became asymmetric. We identified seven pairs of sovereign bond markets for which the null hypothesis of symmetry in correlation of sovereign bond yield dynamics can be rejected. Calculating rolling-window exceedance correlation, we found that the time-varying upper- (i.e. for positive yield changes and lower-tail correlations (i.e. for negative yield changes for pair-wise observed sovereign bond markets normally follow each other closely, yet during some time periods (for most pair-wise observed countries, these periods are around the September 11 attack on the New York City WTC and around the start of the Greek debt crisis the difference in correlation does increase. The results show that the upper- and lower-tail correlation was symmetric before the Eurozone debt crisis for most of the pair-wise observed sovereign bond markets but has become much less symmetric since then.

  1. Effects of physical agitation on yield of greenhouse-grown soybean

    Science.gov (United States)

    Jones, R. S.; Mitchell, C. A.

    1992-01-01

    Agronomic and horticultural crop species experience reductions in growth and harvestable yield after exposure to physical agitation (also known as mechanical stress), as by wind or rain. A greenhouse study was conducted to test the influence of mechanical stress on soybean yield and to determine if exposure to mechanical stress during discrete growth pe