UK PubMed Central (United Kingdom)

A barley (Hordeum vulgare L.) mutant (Az34) has been identified with low basal levels of abscisic acid (ABA) and with reduced capacity for producing ABA in response to water stress....Full Text Available

UK PubMed Central (United Kingdom)

Many plants are known to reduce the toxic effects of high soil boron (B) by reducing uptake of B, but no mechanism for limiting uptake has previously been identified. The B-tolerant cultivar of barley...Full Text Available

UK PubMed Central (United Kingdom)

In vitro translation systems were prepared with supernatant factors from wheat germ and 80S ribosomes from wheat germ, barley embryos, watermelon cotyledons, pea cotyledons, and castor...Full Text Available

UK PubMed Central (United Kingdom)

Nickel was established as an essential micronutrient for the growth of temperate cereal crops. Grain from barley (Hordeum vulgare L. cv `Onda'; containing 40 to 80 nanograms of Ni per...Full Text Available

International Nuclear Information System (INIS)

Field experiments were conducted in the 30-km zone of Gomel's region of the Byelorussia to study factors aecting a biological radionuclide accessibility. A contamination density by radiocesium equaled 2,7-9,9 MBk/m"2, strontium 90 - 0,3-0,5 MBk/m"2 in 1991. A sowing of oats barley, lupin was carried out. It was shown that radionuclide accumulation by agricultural plants was determined basically by biological peculiarities of plants in greater degree than by the contamination density. It was shown that strontium 90 migration from the soil was more intensive than that of radiocesium. 8 tabs.

International Nuclear Information System (INIS)

The results are presented of a study in radioactivity of forage (grass, alfalfa, clover), cereals (wheat, oats, rye, barley) and different agriculture products (fodder beet, sugar beet, leguminous plants, poppy, tobacco, maize, potatoes). Total beta activity, "4"0K, "9"0Sr and "1"3"7Cs activities were studied for the period 1962 to 1975 in selected localities in Slovakia. The highest values of "9"0Sr and "1"3"7Cs were measured in 1963, the lowest levels of "9"0Sr in 1975 while the lowest levels of "1"3"7Cs in 1973. (B.S.).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

Metal contaminated crops from contaminated soils are possible hazards for the food chain. The aim of this study was to find practical and cost-effective measures to reduce metal uptake in crops grown on metal contaminated soils near a former metal smelter in Austria. Metal-inefficient cultivars of crop plants commonly grown in the area were investigated in combination with in-situ soil amendments. A laboratory batch experiment using 15 potential amendments was used to select 5 amendments to treat contaminated soil in a pot study using two Barley (Hordeum vulgare L.) cultivars that differed in their ability to accumulate cadmium. Results from this experiment identified 3 of these amendments for use in a field trial. In the pot experiment a reduction in ammonium nitrate extractable Cd (<41%) and Pb (<49%) compared to the controls was measured, with a concurrent reduction of uptake into barley grain (Cd < 62%, Pb < ...

UK PubMed Central (United Kingdom)

Plant roots exhibit remarkable developmental plasticity in response to local soil conditions. It is shown here that mild salt stress stimulates a stress-induced morphogenic response (SIMR) in Arabidopsis...Full Text Available

UK PubMed Central (United Kingdom)

The transport of arginine into isolated barley (Hordeum vulgare L.) mesophyll vacuoles was investigated. In the absence of ATP, arginine uptake was saturable with a K_m...Full Text Available

UK PubMed Central (United Kingdom)

Proline accumulation in NaCl-treated excised barley (Hordeum vulgare var Larker) leaves was studied. Leaves were treated by placing the cut end in NaCl solutions and allowing the salt...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In order to perform the structural analysis and stress evaluation for frame structures in the nuclear power plants, ADAMS (AIJ Design Analysis and Modules System) has been developed by the addition of the following functions to the ICES-STRUDL system. 1. Load combination and stress evaluation on the basis of specifications for designing steel structure (issued by the Architecture Institute of Japan). 2. Combination of load and stress evaluation of piping support on the basis of the regulations of Ministry of International Trade and Industry. 3. Addition of other functions than that described above. ADAMS enables structural analysis and stress evaluation exactly and efficiently not only for a large scale structure such as the pipe whip protection structure installed inside of the primary containment vessel for many loading cases but also for a large number of structures such as ...

UK PubMed Central (United Kingdom)

The effect of water stress on patterns of nitrate reductase activity in the leaves and nodules and on nitrogen fixation were investigated in Medicago sativa L. plants watered 1 week...Full Text Available

DEFF Research Database (Denmark)

Antisense- or RNAi-mediated suppression of the biosynthesis of nutritionally inferior storage proteins is a promising strategy for improving the amino acid profile of seeds. However, the potential pleiotropic effects of this on interconnected pathways and the agronomic quality traits need to be addressed. In the current study, a transcriptomic analysis of an antisense C-hordein line of barley was performed, using a grain-specific cDNA array. The C-hordein antisense line is characterized by marked changes in storage protein and amino acid profiles, while the seed weight is within the normal range and no external morphological irregularities were observed. The results of the transcriptome analysis showed excellent correlation with data on changes in the relative proportions of storage proteins and amino acid composition. The antisense line had a lower C-hordein level and down-regulated transcript encoding C-hordein. The production of the S-rich B/ - and D-hordeins ...

Energy Technology Data Exchange (ETDEWEB)

The toxicities of 21 different herbicides to algae (Selenastrum capricornutum and Chlorella vulgaris) and to terrestrial plants (radishes, barley, and bush beans or soybeans) were compared to order to determine the feasibility of using a short-term (96-h) algal growth inhibition test for identifying chemicals having potential toxicity in a 4-week terrestrial plant bioassay. The toxicity of each test chemical, usually in combination with a commercial formulation, was evaluated at six nominal concentrations, between 0 and 100 mg/L growth medium in the algal bioassay or between 0 and 100 mg/kg substate in the terrestrial plant bioassay, in terms of both (1) the no-observed-effect concentration (NOEC), i.e., the highest concentration tested at which no significant (P < 0.05, one-sided test) reduction in algal growth rate or in terrestrial plant yield, relative to controls, was ...

UK PubMed Central (United Kingdom)

We discuss the relationship between the dynamically changing tension gradients required to move water rapidly through the xylem conduits of plants and the proportion of conduits lost through embolism...Full Text Available

UK PubMed Central (United Kingdom)

The effects of low concentrations (10 nm or less) of indoleacetic acid and abscisic acid on the phytochrome-mediated attachment of barley root (Hordeum vulgare L., var. Compana)...Full Text Available

International Nuclear Information System (INIS)

Results of investigation of stress corrosion cracking of steam turbine materials in nuclear, fossil and geothermal power plants have been analysed. The role of factors that cause damage to rotor discs, mono block and welding rotors of steam turbines has been shown. These are yield stress and steel composition, stress intensity coefficient and crack growth rate, composition and temperature of the condensed steam and water, electrochemical conditions. The conclusion has been made about the state of stress corrosion cracking of the rotors materials, and main investigation trends which are necessary to solve this problem have been listed.

International Nuclear Information System (INIS)

The disposal of municipal solid waste in an environmentally sound manner is a major problem worldwide. The composting of the organic fraction of refuse transforms it into soil amendment that can be recycled on agricultural lands. In order to promote the use of compost among farmers, agronomic investigations have to evaluate the impact of its use on soil properties and plant growth. In a greenhouse experiment, a sample of locally produced compost was applied to a sandy clay soil at rates equivalent to 0, 25, 50, 100, and 200 t/ha with supplemental addition of NH_4 NO_3 at levels equivalent to 0, 25, 50 and 100 Kg N/ha. Barley (Hordium vulgare L.) and corn (Zea mays L. indentata) were grown as indicator crops and soil properties were determined over a period of 150 days. Plant growth was affected by N starvation until the compost was stabilized in the soil. Nitrogen starvation persisted for a longer period with increasing ...

UK PubMed Central (United Kingdom)

A variety of stress situations may affect the activity and survival of plant-beneficial pseudomonads added to soil to control root diseases. This study focused on the roles of the sigma factor AlgU...Full Text Available

UK PubMed Central (United Kingdom)

The chloroplast and cytoplasmic isoenzymes of phosphoglycerate kinase (PGK) (EC. 2.7.2.3) from Hordeum vulgare leaves have been separated and purified for the first time to apparent...Full Text Available

UK PubMed Central (United Kingdom)

The phytochrome-mediated attachment of root tips of mung bean (Phaseolus aureus) and barley (Hordeum vulgare) to glass is affected by the prior exposure of hydrated...Full Text Available

International Nuclear Information System (INIS)

The research work carried out on mutation breeding in Egypt during the 1980s is summarized. Several mutations have been developed in bread wheat, maize, rice and barley. A higher yield, tolerance to salinity, shorter types and earliness were obtained after use of different mutagens and growth regulators. Great attention has been paid to the fababean and chickpea, particularly in improving their quality and quantity of protein, and their resistance to insect weevils such as Callosobruchus sp. Tolerance or resistance to broom rape has also been reported. Various grain legumes such as lentil, pea, cowpea, bean, fenugreek and lupin received some attention. Mutation work on fibre crops such as cotton, kenaf and flax has led to some promising results. Zero type, glandless and early maturing mutants were obtained in cotton, and early flowering, high yielding (fibre or oil) mutants in flax. Some attention has been given to oil crops such as sesame, rapeseed, peanuts, ...

Science.gov (United States)

High salinity is one of the main factors limiting cotton growth and productivity. The genes that regulate salt stress in TM-1 upland cotton were monitored using microarray and real-time PCR (RT-PCR) with samples taken from roots. Microarray analysis showed that 1503 probe sets were up-regulated and 1490 probe sets were down-regulated in plants exposed for 3h to 100mM NaCl, and RT-PCR analysis validated 42 relevant/related genes. The distribution of enriched gene ontology terms showed such important processes as the response to water stress and pathways of hormone metabolism and signal transduction were induced by the NaCl treatment. Some key regulatory gene families involved in abiotic and biotic sources of stress such as WRKY, ERF, and JAZ were differentially expressed. Our transcriptome analysis might provide some useful insights into salt-mediated signal transduction pathways in cotton and offer a ...

British Library Electronic Table of Contents (United Kingdom)

A wide variety of phytochemicals present in our diet, including fruits, vegetables, and spices, have been shown to possess a broad range of health-beneficial properties. The cytoprotective and restorative effects of dietary phytochemicals are likely to result from the modulation of several distinct cellular signal transduction pathways. Many dietary phytochemicals that are synthesized as secondary metabolites function as toxins, that is, -phytoalexins,- and hence protect plants against insects and other damaging organisms and stresses. However, at the relatively low doses consumed by humans and other mammals, these same toxic plant-derived chemicals, as mild stressors, activate adaptive cellular response signaling, conferring stress resistance and other health benefits. This phenomenon has...

British Library Electronic Table of Contents (United Kingdom)

Survival and growth of terrestrial plants is negatively affected by complete submergence. This is mainly the result of hampered gas exchange between plants and their environment, since gas diffusion is severely reduced in water compared with air, resulting in O2 deficits which limit aerobic respiration. The continuation of photosynthesis could probably alleviate submergence-stress in terrestrial plants, but its potential under water will be limited as the availability of CO2 is hampered. Several submerged terrestrial plant species, however, express plastic responses of the shoot which may reduce gas diffusion resistance and enhance benefits from underwater photosynthesis. In particular, the plasticity of the flooding-tolerant terrestrial species Rumex palustris turned out to be remarkable,...

Energy Technology Data Exchange (ETDEWEB)

Life management system is based on the valid nowadays in Estonian power plants regulation documentation. The system allows to estimate stress distribution in components, find computational assessment of cumulated creep damage, determine when and where it is necessary to cut off the particular number of microsamples or take replicas. Finally, the real metal condition may be assessed on the basis of metallographic specimen research and reasonable 3-R decision - run, repair, replacement - made on further component use. (orig.) 6 refs.

Environmental Research Database

DescriptionThis project aims to develop a hybrid bioremediation/phytoremediation process for sustainable in- situ treatment of hydrocarbon contaminated soils, centred on 3 tenets: 1) Application of wood-chip derived compost enriched with white rot fungi for primary bioremediation; 2) Growth of pre-selected plant species for secondary phytoremediation; 3) Use of stress- adapted mycorrhizal fungi to maximise plant performance. A multidisciplinary approach is essential to optimise bioremediation for the trea [continued...

British Library Electronic Table of Contents (United Kingdom)

Antisense- or RNAi-mediated suppression of the biosynthesis of nutritionally inferior storage proteins is a promising strategy for improving the amino acid profile of seeds. However, the potential pleiotropic effects of this on interconnected pathways and the agronomic quality traits need to be addressed. In the current study, a transcriptomic analysis of an antisense C-hordein line of barley was performed, using a grain-specific cDNA array. The C-hordein antisense line is characterized by marked changes in storage protein and amino acid profiles, while the seed weight is within the normal range and no external morphological irregularities were observed. The results of the transcriptome analysis showed excellent correlation with data on changes in the relative proportions of storage protei...

Energy Technology Data Exchange (ETDEWEB)

The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed ...

British Library Electronic Table of Contents (United Kingdom)

Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2?weeks of salt treatment with 25, 50, 75 and 100?mM NaCl. Results showed that, growth was reduced even by 25?mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions...

Energy Technology Data Exchange (ETDEWEB)

IHI has developed a new Three-Dimensional Computer-Aided Design (3D-CAD) system to improve the design efficiency and quality of the steel structure of nuclear power plants. This system covers every design phase from the initial arrangement of structure to the production design sharing the same database. The system incorporates the design rules and professional expertise of designers, and enable easy and efficient design. The system can easily generate the three-dimensional data for structures, model data for stress analyses and composite arrangement data. The system has already been applied to several plants under construction and has achieved excellent results. The outline of the new CAD system is introduced. (author)

British Library Electronic Table of Contents (United Kingdom)

Homozygous transgenic cotton (Gossypium hirsutum L.) plants that accumulated glycinebetaine (GB) in larger quantities were more tolerant to salt than wild-type (WT) plants. Four transgenic lines, namely 1, 3, 4, and 5, accumulated significantly higher levels of GB than WT plants did both before and after salt stress. At 175 and 275?mM NaCl, seeds of all the transgenic lines germinated earlier and recorded a higher final germination percentage, and the seedlings grew better, than those of the WT. Under salt stress, all the lines showed some characteristic features of salt tolerance, such as higher leaf relative water content (RWC), higher photosynthesis, better osmotic adjustment (OA), lower percentage of ion leakage, and lower peroxidation of the lipid membrane. Levels of endogenous GB in ...

International Nuclear Information System (INIS)

The program introduced here for determining and describing the multi-axial creep of pipes is based, on the one hand, on the results of the nuclear process heat prototype plant material program and, on the other hand, on the possible load conditions which arise for evaluating accidents or extreme working situations. The basis of a theoretical description of multi-axial creep is the invariant theory in which both the von Mises configuration change hypothesis and the Norton creep law are included. Combined tension and torsion are also considered in detail, the superimposition of cyclic stresses in the tensile threshold area is discussed and cases of partial relaxation are explained. Experimental results for the discussed loads are introduced, which have led to satisfactory agreement between theory and experiment. (orig./MM).

International Nuclear Information System (INIS)

By 1970 the first edition of the ASME Code Section XI, Inservice Inspection of Nuclear Reactor Coolant Systems was published. From its inception, the Section XI inservice inspection scope was based on a fundamental risk-based selection process. In other words the inservice inspection scope included components where the consequences of a pressure boundary failure were high. Once the consequence significant system boundaries were established, inspections would then be performed at locations believed to be most susceptible service induced failure. Current Section XI requirements require that inspection locations be selected on the basis of peak stress and fatigue usage values contained in the Design Reports. These original stress calculations were designed to qualify a design and assure that the plant would provide reliable service throughout its design life. For the most part, the fatigue usage values in these reports do not ...

International Nuclear Information System (INIS)

PWR steam generators have suffered from a variety of degradation phenomena. This paper identifies the corrosion-related defects and their probable causes and suggests approaches to correct and prevent corrosive activity. In the attempt to solve the degradation problems, research programs have concentrated on modifying materials, stresses, and the chemical environment in both new and operating steam generators. The following corrosion-related defects have been studied: tube wastage, denting, primary side (ID) intergranular stress corrosion cracking (IGSCC), OD-initiated intergranular attack (IGA), pitting, and corrosion fatigue. Plants affected by wastage have greatly reduced their problem by adopting an all volatile treatment (AVT). In the case of denting, a less aggressive chemical environment is recommended. Primary side IGSCC responds to temperature reduction, stress relief, and material ...

Energy Technology Data Exchange (ETDEWEB)

In an HTR plant high temperature components of Alloy 800 materials are subjected to temperatures from about 550 to 850degC in the long term; higher temperatures may occur in the short term. Thus the creep and stress-rupture parameters govern the design of these components. Since in recent years the scope of experimental data available for Alloy 800 materials has considerably increased, a new evaluation of the creep and creep-rupture properties was performed using a data bank computer. The relationships between the characteristics of the creep and creep-rupture behaviour and the metallurgical parameters were investigated by multilinear regression analyses. On the basis of the results of these analyses and after discussion in material expert committees new material specifications were determined for different types of Alloy 800. They were included into the draft standards DIN 17459 and DIN 17460 under the material standard nos. 1.4958, 1.4958 Rk ...

International Nuclear Information System (INIS)

The AMSE Boiler Code development of design stresses and their optimization for alloys 800 and 800H for conventional and nuclear power plants have coincided with many successful trial installations of these grades of alloy 800. These trial installations, along with laboratory tests, have shown that alloy 800H can be used for long times with a retention of good mechanical properties, including ductility. While gamma prime can be formed, it soon loses its detrimental effect on ductility in service. Sensitization of the alloy also occurs but it, too, has a decreasing effect on corrosion resistance with time in service, especially at elevated temperatures. The authors discuss all of these aspects and conclude that alloy 800 perhaps with low carbon control in the annealed (1800 to 1950degF)(982 to 1066degC) condition gives the optimum combination of properties to 1050degF(566degC) and alloy 800H (.05 to .10%C) solution annealed at 2100 to 2200degF ...

International Nuclear Information System (INIS)

In order to develop competitive and reliable nuclear power generation systems, development of innovative structural design methods is indispensable and risk-based design approach based on the assessment of failure probability is being developed. Fatigue is commonly considered as an important contributor to failure probability in many components of reactor systems and its assessment gives a large influence on total reliability of the plants. In order to assess its effect on the reliability, propagation of cracks needs to be evaluated as well as their initiation and pre-existence probability. As a part of new design approach, efforts are being taken to develop a simplified estimation method for fatigue crack growth under cyclic application of thermal and thermo-mechanical loading. A simplified estimation method of J-integral based on reference stress method and elastic follow-up factor was developed based on many finite element analyses and ...

International Nuclear Information System (INIS)

At the importance increase of UT (ultrasonic testing) with the application of rules on fitness-for-service for nuclear power plants, JAPEIC (Japan power engineering and inspection corporation) started education training for defect detection and sizing technique. Weld joints specimen with EDM (Electro-Discharged Machining) notches, fatigue cracks and intergranular stress corrosion cracks were tested and practiced repeatedly based on a modified ultrasonic method and the defect size measuring accuracy of the trainees was surely improved. Results of the blind test confirmed effectiveness of education training. (T. Tanaka)

British Library Electronic Table of Contents (United Kingdom)

Zeaxanthin is a carotenoid produced by plants and has been associated with protection of the photosynthetic machinery under light stress and, together with lutein, in protection of the central retina of the eye. Zeaxanthin levels in blood plasma have been negatively correlated to the development of AMD (age-related macular degeneration) (Gale et al., 2003). Under normal conditions, plants have a low content of zeaxanthin. The aim of this study was to increase the zeaxanthin content in green vegetables by post harvest treatments. Efficient conditions for activation of the endogenous enzyme system generating zeaxanthin was established and included incubation at low pH (2.5-5.5), with the membrane permeable acetic acid/acetate buffer at room temperature or above for 30min or more. Typically m...

Science.gov (United States)

... Title : STRESS ANALYSIS OF AN AUTOFRETTAGED LOOSE LINER FOR GUN BARREL CONSTRUCTION PRECOMPRESSED IN THE ...

International Nuclear Information System (INIS)

The Belgian Tihange 2 nuclear power plant went into commercial operation in 1983 producing a thermal power of 2785 MW. Since the commissioning of the plant the steam generators U-tubes have been affected by primary stress corrosion cracking. In order to avoid further degradation of the performance and an increase in repair costs, Electrabel, the owner of the plant, decided in 1997 to replace the 3 steam generators. This decision was supported by the feasibility study performed by Tractebel Energy Engineering which demonstrated that an increase of 10% of the initial power together with a fuel cycle length of 18 months was achieved. Tractebel Energy Engineering was entrusted by Electrabel as the owner's engineer to manage the project. This paper presents the role of Tractebel Energy Engineering in this project and the safety analysis program necessary to justify the new operation point and the fuel cycle ...

Science.gov (United States)

Twenty-two landrace-derived inbred lines from the Spanish Barley Core Collection (SBCC) were found to display high levels of resistance to a panel of 27 isolates of the fungus Blumeria graminis that exhibit a wide variety of virulences. Among these lines, SBCC145 showed high overall resistance and a distinctive spectrum of resistance compared with the other lines. Against this background, the main goal of the present work was to investigate the genetic basis underlying such resistance using a doubled haploid population derived from a cross between SBCC145 and the elite spring cultivar Beatrix. The population was genotyped with the 1,536-SNP Illumina GoldenGate Oligonucleotide Pool Assay (Barley OPA-1 or BOPA1 for short), whereas phenotypic analysis was performed using two B. graminis isolates. A major quantitative trait locus (QTL) for resistance to both isolates was identified on the long arm of chromosome 6H (6HL) and accounted for ca. 60% of ...

Energy Technology Data Exchange (ETDEWEB)

To identify radio-protective agent candidate among medicinal plants and to elucidate the mechanism of action of the candidate material by using modern biochemical and molecular biological methods, we screened radio-protective activity among 48 medicinal plants. Seven samples showed above 20% protective activities against oxidative cell damage: Euryale ferox, Glycyrrhiza uralensis, Salvia miltiorrhiza, Eucomia ulmoides, Paeonia suffruticosa, Spirodela polyrrhiza, and Nelumbo nucifera. We also screened for oxidative stress sensitizing activity among other 51 medicinal plants. Among those samples, 11 samples showed good sensitizing effect; Melia azedarach, Agastache rugosa, Catalpa ovata, Prunus persica, Sinomenium acutum, Pulsatilla koreana, Oldenlandia diffusa, Anthriscus sylvestris, Schizandra chinensis, Gleditsia sinensis, and Cridium officinale. We also reported the radio-protective effect of DTT. The ...

British Library Electronic Table of Contents (United Kingdom)

MicroRNAs (miRNAs) are small non-coding RNAs that play vital roles in plant abiotic stress responses via cleavage or translational inhibition of their target mRNAs. Populus euphratica is a typical stress-resistant sessile organism that grows in desert areas. Here, we identified sequences of 12 miRNA precursors from 11 families and 13 mature miRNAs from 12 families by PCR amplification in P. euphratica. To detect expression differences in mature miRNAs and their precursors under dehydration and high salinity shock in P. euphratica, we examined 14 miRNA precursors from 13 miRNA families and 17 mature miRNAs from 17 miRNA families using the SYBR Green RT?PCR assay. This is the first report of expression profiles for both precursor and mature miRNAs in P. euphratica. By profiling both the matu...

Energy Technology Data Exchange (ETDEWEB)

Implementation of Noble Metal Chemical Application (NMCA) in a Boiling Water Reactor (BWR) requires injection of a noble metal compound while the reactor is idle at hot shutdown conditions. In order to minimize outage time, utilities are very pro-actively finding ways to reduce the number of critical path tasks. One of these tasks is to remove some containment vessel drywell head bolts during the NMCA idle time. This, thereby, saves the utilities outage time, or they can perform other tasks as desired. Using design basis conditions and state-of-the-art analytical techniques, detailed finite element stress analyses of the closure region are performed. Two acceptance criteria are evaluated. The first is that contained within Section III of the ASME Code for allowable stresses. The second relates to leak tightness, i.e., with bolt removal the joint must still remain leak tight. This paper describes the activities performed to justify bolt removal ...

International Nuclear Information System (INIS)

With regard to the operation of nuclear power plants, Electricite de France formally recognized in 1973 that it was necessary for safety reasons and economically acceptable to adopt organizational principles of quality assurance that would be applicable both to its own activities and to those of its suppliers. Generally speaking, the form and spirit of the quality assurance programme chosen is based largely on the Code of Practice No. 50-C-QA. In particular, the programme focuses on the flexible character of quality assurance requirements and stresses that in the final analysis product quality depends above all on those to whom the project has been assigned, because it is they who are responsible for meeting the quality objectives set. Ten years of experience with the suppliers of Electricite de France has shown that these suppliers, after some initial difficulty, have been able to adapt the application of quality assurance so as to achieve ...

Energy Technology Data Exchange (ETDEWEB)

The secondary side corrosion of steam generator tubes is the main degradation of components in operating power plants, strongly impacted by chemistry. This is why EDF has largely studied the chemical parameters in its 56 PWRs which might influence corrosion development. The results of 168 hideout returns of chemical species performed on the French plants allowed to draw conclusions on where chemical species are likely to concentrate in steam generators and on the influence of several contaminants on corrosion processes: sodium, chloride, phosphate, organic compounds, etc... Based on laboratory studies and plants feedback, new chemistry specifications were established and are now applied to EDF units to minimize corrosion and operating costs and to provide a good availability while maintaining an excellent safety. Boric acid is added in the secondary water of the 10 oldest units with Inconel 600 MA tubing, highly sensitive ...

Science.gov (United States)

No Abstract Available

Norwegian Open Research Archives (NORA)

Full Text Available

Science.gov (United States)

Sep 16, 2010 ... Taking military operations as an example, there is evidence that stress-related behavioral disorders and mental conditions such as anxiety, ...

International Nuclear Information System (INIS)

The steam generator availability is one of the important problems encountered during the pressurized water nuclear plant operation. Various kinds of corrosion phenomena were observed in the past. These phenomena result from the concentration of impurities mainly in three locations in the steam generators: the tubesheet crevices, the tube support plate crevices, and the sludge pile. Corrections were made in the design and the materials used but a number of steam generators suffer or will suffer from corrosion processes inducing in many cases forcing their replacement. In order to prevent or to retard the corrosions several laboratories have performed experiments to reproduce and to study the corrosion processes. The first step of the degradation is the concentration of chemical species. A method using /sup 24/Na as a radioactive tracer was used to establish the concentration kinetics of caustic which was identified as the major cause of the intergranular attack ...

British Library Electronic Table of Contents (United Kingdom)

The effect of water shortage on growth and gas exchange of maize grown on sandy soil (SS) and clay soil was studied. The lower soil water content in the SS during vegetative growth stages did not affect plant height, above-ground biomass, and leaf area index (LAI). LAI reduction was observed on the SS during the reproductive stage due to early leaf senescence. Canopy and leaf gas exchanges, measured by eddy correlation technique and by a portable photosynthetic system, respectively, were affected by water stress and a greater reduction in net photosynthetic rate (A N) and stomatal conductance (g s) was observed on SS. Chlorophyll and carotenoids content was not affected by water shortage in either condition. Results support two main conclusions: (1) leaf photosynthetic capacity was unaffec...

International Nuclear Information System (INIS)

The critical part of the trimetallic transition joint (type 304 stainless steel/Alloy 800/2.25 Cr-1 Mo steel), the Alloy 800/2.25 Cr-1 Mo steel joint welded with Inconel 182, was subjected to thermal cycling between room temperature and 873 K. The thermal cycling test procedure used produces accelerated failures in transition joints similar to those observed in steam generators of operating power plants. On thermal cycling, precipitation at the weld/ferritic steel interface decreased on post-weld heat treatment. This precipitation increased with increased prior ageing and applied stress. The results of these tests indicated a considerable improvement in performance of the trimetallic transition joint compared to the direct (bimetallic) transition joint. (orig.).

International Nuclear Information System (INIS)

This analysis of the June 8, 1976 California Nuclear Initiative was prepared by the Pacific Gas and Electric Co. The defeat of Proposition 15 in the California election was successful for several reasons. A record 70 percent of the voters in California went to the polls and 97 percent of those voted on the nuclear issue with the results showing defeat by two-to-one. Apparently, the voters perceived the Nuclear Initiative as being too drastic. The campaign for defeat of the initiative stressed the consequences of closing down existing plants and closing off the nuclear option in California, namely: higher costs, job losses, and less-desirable alternatives. The campaign waged for the Initiative seems to have suffered from weak management and lack of consistent messages.

International Nuclear Information System (INIS)

Alloy 800 has been used by Siemens since 1968 and is now used by KWU for U-tubed steam generators in PWR's. The particular grade of alloy 800 that is used is within the ASTM-Specification B 163, but there have been modifications in composition to improve the corrosion resistance. First the permitted upper limit of carbon was reduced to 0.04% and was then further reduced to 0.03% and a stabilisation ratio of Ti : C >= 12 and Ti : C + N >= 8 was specified. The minimum permitted chromium and nickel levels were increased to 20% and 32% respectively. The maximum permitted levels of other elements or impurities were reduced. At the final fabrication stage peening with glass beads on the outer surface was specified to introduce a compressive stress to depth greater than that allowed for production flaws. An account is given of the behaviour of the alloy in service in four power plants already in operation, and future developments are discussed. ...

International Nuclear Information System (INIS)

In view of the importance of the material Alloy 800 in high-temperature reactor plants (HTR), a material data bank was established which is used for statistical evaluation of mechanical and physical material behaviour. Based on investigations on the interconnection between the mechanical properties at high temperatures and the metallurgical parameters, different types of Alloy 800 were specified in compliance with the component requirements. In addition, aspects of corrosion and toughness behaviour were taken into consideration. The specifications and strength characteristics for the different variants of Alloy 800 were incorporated into draft DIN standards after discussion and approval in expert committees. Further important characteristics of the mechanical and physical material behaviour were summarized in HTR material data sheets so as to furnish an improved basis for the design and stress analyses of Alloy 800 components. (orig.).

International Nuclear Information System (INIS)

PWR plants have made efforts to maintain the long-term integrity of the steam generators (SG) by reducing the amount of corrosion products entering the secondary side of the SG. Iron entered the SG can cause several problems: degraded heat conductivity of the SG tubes in locations where iron is deposited, water level oscillations in the SG due to tube support plate hole blockage, and initiation and propagation of inter-granular attacks (IGA) and stress corrosion cracking (SCC). One of the most effective measures, high all-volatile treatment (AVT) chemistry has been applied to actual plants to reduce the flow-accelerated corrosion (FAC) coming from the carbon steel piping. The secondary water chemistry at Genkai NPS 1 and 2 changed, from the Low AVT chemistry to the High AVT chemistry, in November 2006. In this paper, we will describe the results of experiments in applying the use of High pH water in the secondary water ...

British Library Electronic Table of Contents (United Kingdom)

A process combining dark fermentation and photofermentation for production of hydrogen is interesting due to its potential of producing hydrogen at a high yields. In this study, the hydrogen process is compared to a 2nd generation ethanol process with respect to cost and with the aim of increasing our understanding of the pros and cons and giving a clear picture of the present status of the two processes. The hydrogen production cost was found to be about 20 times higher than the ethanol production cost, 421.7&z.euro;/GJ compared to 19.5&z.euro;/GJ. The main drawbacks of the hydrogen process are its low productivity, low energy efficiency, and the high cost of buffer and base required to control the pH.

International Nuclear Information System (INIS)

To ensure safe and reliable power production nuclear power plants must be operated at high level. Non destructive in-service inspections are inseparable part of the effort. Non destructive in-service inspections are essential on the ground of degradation mechanisms existence in nuclear power components. Degradation processes are constituent of operation of each industrial installation including nuclear power plants. Mission of non-destructive testing is degradation detection, closer characterization of its parameters (dimensions) and to supply as much information as possible to nuclear power plant operator. Eddy current testing method can be assigned to surface - volumetric methods. Method enables inspection of electrically conductive materials. It is particularly suitable for inspection of non-ferromagnetic materials like austenitic stainless steel and brass. The method is used for detection of stress ...

Energy Technology Data Exchange (ETDEWEB)

Since the first operation of nuclear steam generator early 1960s, its performance requirements have been met but the steam generator problems have been met but the steam generator problems have been major cause of reducing the operational reliability, plant safety and availability. U-tube assembly of steam generator forms the primary system pressure boundary of the plant and have experienced several types of tube degradation problems. Tube failure and leakage resulting from the degradation will cause radioactive contamination of secondary system by the primary coolant, and this may lead to unplanned plant outages and costly repair operations such as tube plugging or steam generator replacement. For the case of steam generators for heavy water reactors, e.g. Wolsong 2, 3, and 4 NPP, a high cost of heavy water will be imposed additionally. During the plant operation, steam generator tubes can potentially ...

UK PubMed Central (United Kingdom)

Stress has been reported to be a causative factor for male infertility. Withania somnifera has been documented in Ayurveda and Unani medicine system for its stress-combating properties....Full Text Available

UK PubMed Central (United Kingdom)

Rate of dehydration greatly affects desiccation tolerance of recalcitrant seeds. This effect is presumably related to two different stress vectors: direct mechanical or physical stress because of the...Full Text Available

UK PubMed Central (United Kingdom)

The alternative sigma factor ς^B of Bacillus subtilis is required for the induction of approximately 100 genes after the imposition of a whole range of stresses and...Full Text Available

UK PubMed Central (United Kingdom)

Social stress is prevalent in many facets of modern society. Epidemiological data suggest that stress is linked to the development of overweight, obesity and metabolic disease. Although there...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Residual stresses are present in engineering components as an unintended consequence of manufacturing processes, but they are also deliberately introduced to beneficial effect during surface engineering procedures. Plasma nitriding is a process of particular importance for forming tools and dies, giving significant advantages in wear, and fatigue resistance through the generation of near-surface compressive residual stresses. A precise knowledge of the level and distribution of residual stresses that exist in engineering components is necessary for an accurate design and prediction of a component's fatigue resistance. However, measurement of residual stresses is not always possible, which is especially true for forming tools. Therefore, other methods for residual stress evaluation and pred...

Science.gov (United States)

It is shown that the method used for comparing theoretical and experimental results is erroneous and the values of the couple stress parameters obtained for blood flow are incorrect. A method for determining the couple stress parameters is presented. The computational work in the improved method is considerably less. It is observed that both the couple stress parameters are functions of concentration. An empirical relation between concentration and the stress parameters is obtained. The shear viscosity and non-dimensional axial velocity are functions of concentration. Some uses of determining the values of the couple stress parameters are suggested.

Science.gov (United States)

... Mirrors (Preprint) Ryan Conk et al. 15 September 2006 ... 4. TITLE AND SUBTITLE Stress Coatings for Large Scale Membrane Mirrors (Preprint) 5a. ...

UK PubMed Central (United Kingdom)

We explored transcriptional responses of the fission yeast Schizosaccharomyces pombe to various environmental stresses. DNA microarrays were used to characterize changes in expression...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Alloy 600 is commonly used in the primary systems of PWR plants because of its excellent resistance to a stress corrosion cracking and pitting. But a stress corrosion cracking and pitting corrosion are occasionally observed under PWR conditions, which may be correlated with the passive film on the Alloy 600 surface. There is little information on the composition of films growing on the surface of Alloy 600 at high temperature. Therefore, an understanding of the basic electrochemical behaviors about an anodic dissolution and the passivation of the bare surface of metals and alloys provides important information about localized corrosions like a SCC and pitting. Oxide on the steel surfaces in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. Outer layer of the oxide is less ...

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The objective of this study is to evaluate the lifetime of Zr-2.5Nb pressure tube at Wolsung Unit-1. The testing materials (Effective full power year: 9.3 year, Accumulated nuetron fluence: 7.66{approx}8.91 x 1025 n/m{sup 2}) were sampled from M-11 tube at various position(inlet, middle and outlet). The cutting was carried out at hot cell to fabricate CT(Compact tension) specimen with 48 ppm hydrogen content. In the result of DHC test, irradiation-damaged specimen showed 4{approx}6 times faster DHC velocity(5.298E-0.8{approx}7.039E-8 m/s: 182 .deg. C) than non-irradiated specimen. These DHCV results also show slight faster than one of specimen from Pickering plant (average DHCV: 4.5E-8 m/s: 182 .Deg C). This faster DHCV can be explained with the fact that Wolsung Unit-1 have been operated in a severe conditions(higher cooling water temperature, high power and efficiency) than Pickering one. The striation spacing which was seen DHC fracture surface at irradiated ...

International Nuclear Information System (INIS)

In association with periodic inspection of CANDU nuclear power plant components, Canadian Standards Association issued CSA N285.8 in 2005 as technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors. This first version, CSA N285.8 involves procedures for, firstly, the evaluation of pressure tube flaws, secondly, the evaluation of pressure tube to calandria tube contact and, thirdly, the assessment of a reactor core, and material properties and derived quantities. The evaluation of pressure tube flaws includes delayed hydride cracking evaluation the procedures of which are stipulated based on the existing delayed hydride cracking models. For example, the evaluation of flaw-tip hydride precipitation during reactor cooldown involves a procedure to calculate the equilibrium hydrogen equivalent concentration in solution at the flaw tip, Htipas follows: Htip=Hfexp[- (VH delta no.)/RT], where Hf is the total bulk hydrogen ...

Energy Technology Data Exchange (ETDEWEB)

In the development of the man-made island siting technology of nuclear power plants, assessing the stability of the seawall against large ocean waves and earthquakes is indispensable. Concerning with the seismic stability of the seawall, prediction of the deformation like sliding and settlement of the seawall during earthquake including the armour units in front of the caisson becomes important factor. For this purpose, the authors have developed the two-dimensional DEM-FEM coupled analysis method (SEAWALL-2D) to predict the deformation of the seawall covered with the armour units during earthquake. In this method, movements of the armour units are calculated in DEM analysis part and deformation of the caisson, rubble moundsand seabed and back fill are calculated in FEM analysis part taking the nonlinearity of the soil materials based on the effective stress into account. Numerical simulations of dynamic centrifuge model tests of the seawall ...

Energy Technology Data Exchange (ETDEWEB)

Industrial facilities offer a wide variety of design challenges to engineers, including the mechanical engineers who design the HVAC, the process, exhaust, and other required mechanical systems; the mechanical contractors who install and maintain the systems (and who also may do design work); and the owners` engineers who are responsible for the day-to-day operation of their facilities. Along with the responsibility to see that all systems function as intended is the responsibility to ensure that all worker health concerns are addressed. These include heat stress avoidance and the proper control of harmful substances. The services of industrial hygienists may be required to ensure this. These may be independent consultants or the staff members of mechanical design firms. In addition, it is not unusual for major corporations that own manufacturing plants to have staff industrial hygienists. The accompanying sidebar presents a checklist of items ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Hydrogen release and distribution in nuclear power plant containment is an important safety issue. Selection of a proper turbulence model is important for accurate estimation of the mixing process. The selection of turbulence model is dictated by the best compromise between accuracy and computational efforts. For this, three different turbulence models, viz. Standard k-{epsilon}, RNG k-{epsilon} and Reynolds Stress Model, based on Reynolds averaged Navier Stokes equations (RANS) approach, were used. The computations were done using the CFD code FLUENT, which is based on the control volume methodology. The computational results were compared with the experimental results of HYMIS test facility, where helium was used to simulate hydrogen. The processes of helium plume rise, multiple plume merging, distribution and mixing were studied. Based on these computations, a simple analytical/empirical zone based model was ...

Energy Technology Data Exchange (ETDEWEB)

"What happens to conventional metals near the ocean?" you might ask the workers who are repairing the water tower at Jones Beach. They will tell you that both the tower's steel framework and copper roof show extensive corrosion from the salty air. To power future generations of cars, homes, utility plants, and even particle accelerators, unprecedented levels of efficiency will be needed. Such efficiency will require new unconventional alloys and composite materials that can also withstand high temperatures, intense radiation fluxes, high stresses, and other extreme conditions in highly corrosive environments that accelerate the aging and weakening of materials, as salty air weakens steel and copper. During the lecture, Simos will discuss the demands of next-generation energy systems and focus on the extreme conditions that materials used in these systems will perform under. He will also explain Brookhaven Lab's role in past, ...

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The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear ...

Energy Technology Data Exchange (ETDEWEB)

The stability of a solid ice cover subjected to rapidly varying water levels and discharge was investigated. The support from the bank limits the stress in the ice cover and consequently bank contact must be maintained to ensure ice cover stability. An analysis was required of the stability of ice hinges, a flexible connection between a solid ice cover and the riverbank. Phase II and phase III of the research involved a field study of the Peace River, investigating the evolution of ice hinges with water level variation, from initial ice cover cracking parallel to the banks, to a fully developed hinge. A test program of midwinter discharge variations was undertaken to gather specific data and measurements of ice hinge link length, ice thickness, hinge joint behavior, riverbank geometry, and response of ice hinging to water level variation. As a result of the program, concepts developed throughout the study were confirmed, preliminary guidelines for hydroelectric ...

Energy Technology Data Exchange (ETDEWEB)

Transition joints in power plants between ferritic steels and austenitic stainless steels suffer from a mismatch in coefficients of thermal expansion (CTE) and the migration of carbon during service from the ferritic to the austenitic steel. To overcome these, nickel-based consumables are commonly used. The use of a trimetallic combination with an insert piece of intermediate CTE provides for a more effective lowering of thermal stresses. The current work envisages a trimetallic joint involving modified 9Cr-1Mo steel and 316LN austenitic stainless steel as the base materials and Alloy 800 as the intermediate piece. Of the two joints involved, this paper describes the choice of welding consumables for the joint between Alloy 800 and 316LN. Four consumables were examined: 316, 16-8-2, Inconel 82 and Inconel 182. The comparative evaluation was based on hot cracking tests and estimation of mechanical properties and coefficient of thermal expansion. ...

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Wastenet

aged gracefully: premature and accelerated corro - sion, erosion, and stress are raising maintenance costs.Last

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Energy Technology Data Exchange (ETDEWEB)

The development and improvement of materials plays a key role in energy technology, particularly in power plant technology, because materials are crucial to plant performance and power availability. This becomes particularly clear when one considers that modern power plants generate temperatures of up to 600 C and pressures of up to 230 bar in order to increase process efficiency, conserve resources and reduce CO{sub 2} emissions. Modern heat-resistant materials for power plant technology are customised materials which have been developed to meet the specific requirements of special applications. After the requirement profile has been determined the material is developed or optimised on the basis of previous experiences gained with materials in power plant technology. Basic heat-resistant materials are ferritic materials containing 9 to 12% Cr as well as additions of Mo, V, Nb and ...

Energy Technology Data Exchange (ETDEWEB)

The macroscopic stress distribution across an annealed Zircaloy-4 gas tungsten arc weld was measured by neutron time-of-flight diffraction at the SMARTS diffractometer at Los Alamos National Laboratory. The stresses after annealing are about 40% lower than those in the same weld prior to heat treatment. The intergranular strains in the reference coupons, which give the macroscopic stress free lattice spacings, are consistent with the difference in cooling the strongly textured plate and the weakly textured weld.

Science.gov (United States)

In this project the influence of residual compression stresses on the stress corrosion cracking behaviour of the turbine disc steel 26 NiCrMoV 14 5 (Rp(sub 0.2) = 850 N/mm(sup 2)) was investigated. The residual compression stresses were produced by shot p...

Energy Technology Data Exchange (ETDEWEB)

The Alloy 800 tubes used in CANDU 6 steam generators have not experienced significant corrosion damage to date, which may be attributed to successful water chemistry control strategies. However, it is known that Alloy 800, like other steam generator (SG) tubing materials, is not immune to corrosion, especially pitting, under some plausible but off-specification operating scenarios. Electrochemical measurements provide information on corrosion susceptibility and rate, which are known to be a function of water chemistry. Using laboratory data in combination with chemistry monitoring and diagnostic software it is possible to assess the impact of plant operating conditions on SG tube corrosion for plant life management (PLIM). In this context, this paper discusses the results of electrochemical measurements made to elucidate the corrosion behaviour of Alloy 800 SG tubes under conditions simulating those plausible in SG crevices. In addition to ...

Science.gov (United States)

Title list.

Energy Technology Data Exchange (ETDEWEB)

Natural fractures and in situ stresses commonly dictate subsurface reservoir permeability and permeability anisotropy, as well as the effectiveness of stimulation techniques in low-permeability, natural gas reservoirs. This paper offers an initial prediction for the orientations of the fracture and stress systems in the tight gas reservoirs of the Frontier Formation, in the Green River basin of southwestern Wyoming. It builds on a previous report that addressed fractures and stresses in the western part of the basin and on ideas developed for the rest of the basin, using the principle that thrust faults are capable of affecting the stress magnitudes and orientations in little-deformed strata several hundreds of kilometers in front of a thrust. The prediction of subsurface stresses and natural fracture orientations is an undertaking that requires the willingness to revise models as ...

Energy Technology Data Exchange (ETDEWEB)

Approximately 95% of the world`s integrated chips are packaged using a hot, high pressure transfer molding process. The stress created by the flow of silica powder loaded epoxy can displace the fine bonding wires and can even distort the metalization patterns under the protective chip passivation layer. In this study the authors developed a technique to measure the mechanical stress over the surface of an integrated circuit during the molding process. A CMOS test chip with 25 diffused resistor stress sensors was applied to a commercial lead frame. Both compression and shear stresses were measured at all 25 locations on the surface of the chip every 50 milliseconds during molding. These measurements have a fine time and stress resolution which should allow comparison with computer simulation of the molding process, thus allowing optimization of both the manufacturing process and mold ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this study is to develop the methodology which enables to identify the mechanical properties of element such as stress intensity factor by using the AE parameters. Considering the multivariate and nonlinear properties of AE parameters such as ringdown count, rise time, energy, event duration and peak amplitude from fatigue cracks of machine element the principal component regression(PCR) and artificial neural network(ANN) models for the estimation of stress intensity factor were developed and validated. The AE parameters were found to be very significant to estimate the stress intensity factor. Since the statistical values including correlation coefficients, standard mr of calibration, standard error of prediction and bias were stable, the PCR and ANN models for stress intensity factor were very robust. The performance of ANN model for unknown data of stress intensity ...

KoreaScience (Korea)

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CERN Document Server

Nuclear plants decommissioning

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UK PubMed Central (United Kingdom)

Vulnerability to xylem embolism by freeze-thaw cycles and water stress was quantified in ring-porous (Quercus gambelii Nutt.), diffuse-porous (Populus tremuloides Michx.,...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The temperature dependence of the dislocation mobility threshold is investigated on the basis of a dislocation model suggested by Frenkel-Kontorova. The critical value is obtained for the stress/temperature, corresponding to the dislocation depinning from its equilibrium position. The universal behaviour of a barrier height at finite stress and temperature is revealed and investigated.

UK PubMed Central (United Kingdom)

Stress strongly inhibits proliferation of granule cell precursors in the dentate gyrus, while voluntary running has the opposite effect. Few studies, however, have examined the possible effects...Full Text Available

UK PubMed Central (United Kingdom)

The RNA-binding protein Hfq is recognized as an important regulatory factor in a variety of cellular processes, including stress resistance and pathogenesis. Hfq has been shown in several bacteria to...Full Text Available

International Nuclear Information System (INIS)

Research highlights: ? Correlations between microstructure and internal stress during Ti anodising are established. ? Large internal compressive stresses are accumulated in the film during anodising upto 12 V. ?A transition from compressive to tensile stress is observed when the cell voltage exceeds 12 V. ? At 40 V, the oxide films consist of two regions with different compositions and microstructures. Crystallisation of amorphous to anatase TiO2 contributes to the compressive stress relaxation. - Abstract: The relationship between the microstructural and internal stress evolution during Ti anodising is discussed. Samples anodised galvanostatically to 12 V and 40 V, corresponding to different stages of the internal stress evolution, were examined by in-plane and cross-section transmission electron microscopy. Electron diffraction patterns have been complemented ...

CERN Document Server

Residual Stresses in Ta, Mo, Al and Pd Thin Films Deposited by E-Beam Evaporation Process on Si and Si/SiO 2 Substrates

UK PubMed Central (United Kingdom)

The widely accepted oxidative stress theory of aging postulates that aging results from accumulation of oxidative damage. Surprisingly, data from the longest-living rodent known, naked mole-rats [MRs;...Full Text Available

Wastenet

... Austrian Environment Minister Nikolaus Berlakovich called for such stress tests on Sunday (13 March) to make sure that nuclear power stations were quake-proof following Japan's massive earthquake and tsunami. Austria, a mountainous country rich in geothermal energy, has no NPPs and no plans to develop ...

Energy Technology Data Exchange (ETDEWEB)

A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground ...

Science.gov (United States)

This report is a continuation of the former efforts to elucidate the behavior of ferrocement concrete in static and dynamic stress fields. The influence of various reinforcements on pre and post cracking of thin sections forms the main topic of this repor...

UK PubMed Central (United Kingdom)

Oxidative stress has been implicated in the etiology of age-related muscle loss (sarcopenia). However, the underlying mechanisms by which oxidative stress contributes to sarcopenia have not been thoroughly...Full Text Available

UK PubMed Central (United Kingdom)

Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of cellular aging. Mild stress-induced hormesis can be an effective way for reducing the accumulation of molecular...Full Text Available

UK PubMed Central (United Kingdom)

Neurons in the hippocampal CA1 region are particularly sensitive to oxidative stress (OS), whereas those in CA3 are resistant. To uncover mechanisms for selective CA1 vulnerability to OS, we...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundA strong association between stress resistance and longevity in multicellular organisms has been established as many mutations that extend lifespan also show increased...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundClara cell protein (CC16), the main secretory product of bronchiolar Clara cells, plays an important protective role in the respiratory tract against oxidative stress and...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundTrichloroethylene (TCE) may induce oxidative stress which generates free radicals and alters antioxidants or oxygen-free radical scavenging enzymes.MethodsTwenty...Full Text Available

UK PubMed Central (United Kingdom)

The sirtuin Sirt6 is a NAD-dependent histone deacetylase that is implicated in gene regulation and lifespan control. Sirt6 can interact with the stress-responsive transcription factor NF-κB...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The influences of compressive stress on the dielectric properties of (1 - x)Pb(In{sub 1/2}Nb{sub 1/2})O{sub 3}-xPbTiO{sub 3} (x = 0.1-0.5) ceramics was investigated in this study. The dielectric properties were measured under compressive stress applied parallel and perpendicular to electric field. The results clearly showed that the superimposed compression stress had pronounced effects on the dielectric properties of PIN-PT ceramics. In general, with increasing compressive stress the dielectric constant of the ceramics increased and decreased when the stress was applied parallel and perpendicular, respectively, to the electric field direction. The dielectric loss tangent, however, decreased in both stress cases. The observations were mainly interpreted in terms of competing influences of the domain switching through non-180 deg. domain walls, clamping of domain ...

UK PubMed Central (United Kingdom)

BackgroundArsenic (As) exposure during pregnancy induces oxidative stress and increases the risk of fetal loss and low birth weight.ObjectivesIn...Full Text Available

UK PubMed Central (United Kingdom)

The cofactor nicotinamide adenine dinucleotide (NAD+) has emerged as a key regulator of metabolism, stress resistance and longevity. Apart from its role as ...Full Text Available

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International Nuclear Information System (INIS)

The threshold stress intensities for stress corrosion crack propagation in beta titanium alloy 38-6-44, Ti3Al-8V-6Cr-4Mo-4Zr, has been determined in salt water and methanolic solutions. The alloy was immune to stress corrosion cracking (SCC) in aqueous sodium chloride solutions (marine atmosphere). However, in methanolic solutions, the alloy was very susceptible to SCC. This marked susceptibility in methanolic solutions can be mitigated by the addition of an inhibitor: sodium nitrate. Crack extension in the alloy was transgranular and failure occurred by brittle quasi-cleavage in methanolic solutions.

Science.gov (United States)

... without the problem of purple plague. The Au-Ni-In evaporated ... surface and bonding degradation (purple plague) St step-stress ...

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PMID:534760

International Nuclear Information System (INIS)

... Yoshiaki Toshiba Corp., Nuclear Power Division, Yokohama, Kanagawa (Japan)

Energy Technology Data Exchange (ETDEWEB)

Stress relaxation was studied at 408 K on AZ31 reinforced by ceramic foam produced by in situ foaming of filler loaded preceramic polymer melt. Reinforcement causes significant enhancement of the resistance against stress relaxation compared to AZ91. It is correlated with hardening by the ceramic skeleton as well as ceramic particles formed in the AZ31-matrix. (orig.)

UK PubMed Central (United Kingdom)

Stress exposure increases the risk of addictive drug use in human and animal models of drug addiction by mechanisms that are not completely understood. Mice subjected to repeated forced swim stress...Full Text Available

Science.gov (United States)

During the erection of the Sandia 34-Meter VAWT Test Bed, the induced gravitational stress state in the turbine blades and their associated deflections were measured. This manuscript details the measurements that were taken on the Test Bed blades during erection and compares them to the stresses and deflections predicted by the NASTRAN finite element code.

Energy Technology Data Exchange (ETDEWEB)

Economic and safe operation of nuclear power plants requires reliable steam turbines with high efficiencies. The progress in flow mechanics achieved over the past few years has allowed the use of powerful methods of flow calculation in developments of new blading with greatly enhanced efficiencies. Thanks to the latest manufacturing techniques, the newly developed blading systems can be produced at low cost. Next to progress in flow mechanics, also the broadbased use of advanced finite-element calculations resulted in a more thorough grasp of the many problems associated with structural mechanics assessment of steam turbine components. The theoretical methods have been supplemented by comprehensive efforts in fracture mechanics and experimental materials studies, thus helping to create a reliable knowledge base which will help to avoid the dreaded stress corrosion cracking phenomenon, in components of steam turbines. The measures introduced to ...

British Library Electronic Table of Contents (United Kingdom)

A kind of metastable beta titanium alloy, i.e. Ti-10Mo-8V-1Fe-3.5Al, was aged under elastic compressive stress. Transmission electron microscopy (TEM) investigations revealed that, in the stress-aged samples, precipitated alpha plates were parallel to each other. However, in the conventionally aged samples, alpha plates intersected each other. In other words, variant of alpha plate was selected in the stress-aged samples. Tensile tests showed that, at equivalent tensile strength, the stress-aged samples exhibited higher ductility, compared to the conventionally aged ones.

Energy Technology Data Exchange (ETDEWEB)

The accurate measurement of a stress level is one of the most important issues in a stress diagnosis and its measurement could be of great value in clinical medicine. Stress has a potent effect on the spirit and physical condition of an individual. There are various methods available for its measurement. Some of the commonly used techniques for the diagnosis of a stress level include analysis of the body fluids, questionnaire assessments, psychophysiological evaluations and by determining heart rate variability (HRV) of subjects. However, the existing diagnostic methods have several defects like, a low sensitivity, inaccuracy and long of operation time. In this report, we present a diagnostic technology to detect a stress level which is the origin of various diseases. This method can be of great help in providing an early diagnosis through a biosensor and might play a vital role in ...

International Nuclear Information System (INIS)

Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research ...

International Nuclear Information System (INIS)

Internal pressure creep tests as well as uniaxial creep tests were conducted on 9Cr and 12Cr steels welded joints in order to evaluate creep strength of the high chromium steels welded parts under multiaxial stress conditions, where a welding direction of the internal pressure specimen was longitudinal one. Except under high stress conditions, cracks occurred at fine grained HAZ region for both materials, i.e., the type IV mode fracture. Regarding creep voids distribution along thickness direction of the internal pressure specimens, the creep voids were predominantly observed in the middle of the thickness at the HAZ region while they might be negligible in outer and inner surface of the specimen. Finite element analysis which considers HAZ and weld metal properties revealed that the principal stress (hoop stress) and the stress multiaxiality are the largest in the middle of the ...

Science.gov (United States)

The main purpose of this paper is to explore a numerical algorithm for determining the contact stress when a circular crowned roller is compressed between two plates. To start with, the deformation curve on a plate surface will be derived by using the contact mechanical model. Then, the contact stress distribution along the roller which occurs on the plate surface is divided into three parts: from the center of contact to the edge, the edge and apart from the contact line. The first part is calculated by the elastic contact theorem for the contact subjected to nominal stress between non-crowned parts of roller and plates, the second part is obtained by the classical Hertzian contact solution for the contact between crowned parts of roller and plates, and the third part is simulated as exponential decay. In order to overcome the defect of the half space theorem, in which a plate with infinite thickness is assumed initially, ...

Energy Technology Data Exchange (ETDEWEB)

The aim of the present study was to describe the distribution and remobilization of plutonium (Pu) in the sediments off the Rhone river mouth. Most of the {sup 238}Pu and {sup 239,240}Pu isotopes introduced into the Rhone River were discharged by the liquid effluents released from the Marcoule reprocessing plant, located 120 km upstream the river mouth. Due to its high affinity for particles and its long half life, {sup 238}Pu is a promising tracer to follow the dispersion of particulate matter from the Rhone River to the Mediterranean Sea. During the 3 REMORA cruises, sediment samples were specifically collected in the Rhone pro-delta area and more offshore on the whole continental shelf of the Gulf of Lions. The measurements of alpha emitters gave a first detailed spatial distribution of Pu isotope concentrations in surface sediments off the Rhone mouth. Using {sup 137}Cs concentrations and their correlations with Pu isotopes, we were able to give a first ...

UK PubMed Central (United Kingdom)

The concept of plant intelligence, as proposed by Anthony Trewavas, has raised considerable discussion. However, plant intelligence remains loosely defined; often it is either perceived as practically...Full Text Available

International Nuclear Information System (INIS)

Nuclear power in Romania was initiated on the basis of CANDU reactor type technology, an option found to fulfill the requirements for a sustainable economic development, to support the electric energy demand of the country and to ensure the population and environment protection. The construction of the Cernavoda NPP was heavily based on the Romanian industry participation and basic and applied nuclear research national resources. The experience acquired from Cernavoda NPP Unit 1 will be fructified in the construction of Units 2-5 to be built. The Romanian Ministry of Education and Research implemented a nuclear national program for research and development taking into account the European Union requirements and recommendations, the cooperation with the IAEA - Vienna and the Romanian government policy on short and medium terms in the nuclear field. The research-development program targeted: the reactor physics and nuclear fuel management; the operation safety of Cernavoda NPP Unit 1; ...

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Callus cultures derived from pith tissue of Nicotiana tobacum were grown on two media either under continuous illumination or in complete darkness. The first medium limited greening ability of callus grown in the light (3 milligrams per liter naphthalene acetic acid, 0.3 milligram per liter 2-isopentenylaminopurine, Murashige and Skoog salts, and 2% sucrose). The second medium encouraged chlorophyll synthesis (greening) though not shoot formation (0.3 milligram per liter naphthalene acetic acid; 0.3 milligrams per liter 2-isopentylaminopurine). To measure intracellular concentrations, calli were grown for 15 days on these standard media containing (U-/sup 14/C)sucrose. The dry weight proportions of the calli (as a fraction of fresh weight) and many metabolite concentrations nearly doubled in light-grown cells compared to dark-grown cells and increase 30 to 40% on low-auxin media relative to high-auxin media. Glutamine concentrations (from 4 to 26 millimolar) were very high, probably ...

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During the service in nuclear power plants, steam generator (SG) tubing will suffer from a vibration with a frequency from 30-40 Hz. This means that SG tubing will undergo a very high cycle fatigue process during the design life time (25 years=about 3x10{sup 10}cycles). The material degradation and the very high cycle fatigue life of SG tubing materials due to the vibration are therefore of concern. In this investigation, the fatigue properties of Alloy 690 and Alloy 800 SG tubing in the very high cycle fatigue regime (higher than 10{sup 7} cycles) and strain controlled fatigue at temperatures up to 330{sup o}C have been investigated. The fatigue properties of SG tubing of Alloy 690 are comparable to that of wrought material. The strain controlled fatigue properties of Alloy 690 and Alloy 800 are slightly better at 288{sup o}C than at room temperature (RT). At the stress near the fatigue endurance, the influence of temperature on the high cycle ...

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Stabilized austenitic steels can suffer intercrystalline stress corrosion cracking under BWR water conditions. This experience of the last three years, which is important for German nuclear power station technology, has resulted from the discovery of cracks, which were detected in pipework made from titanium-stabilized 1.4541 charged with hot reactor water in six boiling water reactors and in core components made from niobium-stabilized 1.4550 of one BWR plant. Remedies to the pipework have been found by applying optimized materials and fabrication procedures and also by improving water chemistry conditions. (orig.) [Deutsch] Stabilisierte austenitische Staehle koennen unter SWR-Reaktorwasser-Bedingungen interkristalline Spannungsrisskorrosion (IKSpRK) erleiden. Diese fuer die deutsche Kernkraftwerkstechnik bedeutsame Erfahrung der letzten drei Jahre ergab sich aus Rissbefunden, die in mit heissem Reaktorwasser beaufschlagten Rohrleitungen aus ...

International Nuclear Information System (INIS)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is formed by a dissolution and precipitation mechanism. Growth processes of the inner layer and the outer ...

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Correlation between mechanical stress and hydrogen effects on radiation damage in polycide-gate MOS capacitors was investigated as a function of gate-oxide thickness. The compressive stress magnitude was altered by varying the silicide (TiSi/sub 2/ or WSi/sub 2/) thickness in the polycide-gate electrode, and hydrogen introduction into gate-SiO/sub 2/ film was carried out by diffusion from plasma-deposited silicon-nitride passivation film (SiN-Cap). In a MOS capacitor without passivation film (No-Cap sample), it was found that compressive stress on gate-SiO/sub 2/ reduces both positive charge build-up (..delta..Qot) and interface-trap generation (..delta..Dit). Radiation induced shift, ..delta..Qot exhibits a smaller stress effect as compared with ..delta..Dit. As gate-SiO/sub 2/ thickness decreases, the stress effect on ..delta..Qot increases, while this effect on ..delta..Dit ...

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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International Nuclear Information System (INIS)

Finnish (May 1971). Finland Kilpelaeinen, JE Imatran Voima Osakeyhtio,

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The aim of this research project, funded jointly by SILMU and by the Agricultural Research Centre of Finland, was to evaluate the possible effects of changes in climate and carbon dioxide concentration on the growth, development and yield of field crops and on crop pests and diseases in Finland. The study focused on two cereal crops (spring wheat and spring barley), a grass species (meadow fescue), some common pathogens of cereals and potato, insect pests of small fruits and nematode risk of potato and sugar beet. The results of this study indicate the following effects on crop production of the `best guess` climate change anticipated for Finland by 2050: A lengthening of the potential growing season of 3-5 weeks. A northward expansion of about 250-500 km in suitability for cereal production. Increased yields of adapted spring cereals. New, longer-season cultivars would benefit from both higher temperatures and elevated CO{sub 2}. Improved potential for the ...

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The paper present the results of the study on D.U. (depleted uranium) contamination in the environment and possible effects on animal healths in the region o f Bujanovac. Samples of soil, feed, leaves, grass, lichen, moss, honey and water were collected randomly in 2003/2004 in the vicinity of the target area (500-1000 m) and 5 km from the target area. Activity of the radionuclides ({sup 226}Ra, {sup 232}Th, {sup 40}K, {sup 210}Pb, {sup 238}U, {sup 235}U, {sup 137}Cs, {sup 7}Be) in soils, grass, lichen, moss and honey was determined on Hp Ge detector (Canberra, relative efficiency 23%) by standard gamma spectrometry. Total alpha and beta activity in water was determined on proportional alpha/beta counter (Canberra 2400, efficiency for alpha emitters 11%, efficiency for beta emitters 30%). Non significantly higher values of concentrations of {sup 226}Ra, {sup 232}Th, {sup 238}U and {sup 235}U were measured in the immediate vicinity of the targeted site, but {sup 235}U/{sup 238}U ...

International Nuclear Information System (INIS)

A set of equations describing a stress-mediated evolution of the nonequilibrium dopant-defect system has been derived and analyzed. Together with coupled diffusion of dopant atoms and point defects, we consider the drift of all mobile species in different charge states, namely vacancies, self-interstitials, and pairs 'dopant atom-point defect', in the field of stress. It has been shown that stresses may affect the diffusion of dopant atoms mainly in two ways: (1) directly, due to the drift of the pairs in the field of stress; (2) indirectly, by the formation of nonuniform defect distribution due to the drift of point defects. On this basis, various features of doping processes, such as phenomena of 'uphill' impurity diffusion near the surface (within the framework of the first or second mechanisms) and the peculiarities of high concentration phosphorus diffusion (due to the second mechanism), can be ...

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Machines and structures, such as automobiles are usually subjected to biaxial or three-axial stresses instead of uniaxial stress. However, research on a fatigue failure under multi-axial stress has not been fully presented because such experiments are difficult. To solve this problem, we developed the servo biaxial fatigue-testing machine. In this research, we performed the biaxial fatigue tests of a magnesium alloy in order to clarify the effects from different heat treatments. Magnesium alloy is the lightest in weight among metal materials for structural use. The fatigue characteristics of a magnesium alloy are indispensable in order to create the design which ensures the reliability and the safety of the vehicles especially in long-distance run. The main conclusions are summarized as follows; (1) The mechanical property of magnesium alloy AZ31B falls by heat treatment at low temperature. (2) The crack progress speed ...

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The effects of gate and drain bias stresses on thin film transistors fabricated in polysilicon films crystallized using the advanced sequential lateral solidification excimer laser annealing (SLS ELA) process, which yields very elongated polysilicon grains and allows the fabrication of TFTs without grain boundary barriers to current flow, are investigated as a function of the active layer thickness and of the TFT orientation relative to the grains. The application of hot carrier stress, with a condition of V{sub GS} = V{sub DS}/2, was determined to induce threshold voltage, subthreshold swing and transconductance degradation for TFTs in thicker polysilicon films and the associated stress-induced increase in the active layer trap density was evaluated. However, this device degradation was drastically reduced for TFTs fabricated in ultra-thin films. Furthermore, the application of the same stress ...

International Nuclear Information System (INIS)

The effect of mean stress, or the stress ratio (R), on the fatigue-crack growth (FCG) behavior of #alpha#-aged and #omega#-aged microstructures of the beta titanium alloy Ti-10V-2Fe-3Al was investigated. While the mean stress had a negligible effect on the FCG behavior of the #alpha#-aged microstructure, a strong effect was observed in the #omega#-aged microstructure. In particular, the values of the threshold stress-intensity range (#DELTA#K_t_h) exhibited a strong dependence on R in the #omega#-aged microstructure, while this dependence was weak in the #alpha#-aged microstructure. These effects seem to arise primarily from fracture-surface roughness-induced crack closure. The crack closure levels for the #alpha#-aged microstructure were found to be very low compared to those for the #omega#-aged microstructure. Transmission electron microscopy and scanning electron microscopy studies of ...

International Nuclear Information System (INIS)

High strain fatigue problem in steam turbine. Cyclic stress strain hysteresis loops and stress relaxation behaviour in 16 h dwell period tests. Variation of stress and strain during tests under nominally strain controlled conditions. Definition of test conditions and of criteria for crack initiation and failure. Comparison of reverse bend and push pull failure data. (orig.) 891 RW/orig. 892 RKD.

International Nuclear Information System (INIS)

A study of stress corrosion cracking susceptibility of Zircaloy-4 in chloride-containing aqueous methanolic media is presented. The influence of water content is investigated in the 5-100 vol. % water range. The dependence of stress corrosion cracking on potential is evidenced. A close correlation is established with pitting susceptibility determined by a statistical analysis of induction times. A correlation with the repassivation potential is observed in the water-rich solutions. In the low water content solutions, two repassivation curves are determined according to the experimental technique. Pit morphology and fractography show a transition from aqueous to organic media. (author).

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Bragg peaks obtained in X-ray stress analysis studies are often asymmetric. The use of K/sub ..beta../ rather than K/sub ..cap alpha../ radiation simplifies the problem of peak location, as only one Bragg peak needs to be analysed. It is shown, however, that the common practice of fitting a parabola to the top 15% of the data in a Bragg peak in order to determine the peak position, when the fitted region is asymmetric, can lead to large errors in the calculated stress. Asymmetric pseudo-Lorentzian functions have been found to provide the most satisfactory fits.

International Nuclear Information System (INIS)

It has been found out that 30HGSNA steel undergo cracking under action of stresses in aqueous solutions containing oxygen, while it show high resistance in deoxidated solutions. The purpose of such phenomena is the existence of sulfur inclusions in steel which are a centers of denting corrosion. That points acting as a stresses concentrators where pH factor decreases including hydrogen formation and its absorption in the metal. That mechanism is the main purpose of brittle steel cracking observed in oxygen rich solutions. (author).

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Past airfoil configurations have been used to improve aerodynamic performance and engine efficiencies. The present airfoil configuration further increases component life and reduces maintenance by reducing internal stress within the airfoil itself. The airfoil includes a chord and a span. Each of the chord and the span has a bow being summed to form a generally "C" configuration of the airfoil. The generally "C" configuration includes a compound bow in which internal stresses resulting from a thermal temperature gradient are reduced. The structural configuration reduces internal stresses resulting from thermal expansion.

Science.gov (United States)

Alcoholism; Anxiety Disorders; Generalized Anxiety Disorder; Post-Traumatic Stress Disorder; Panic Disorder; Obsessive-Compulsive Disorder

UK PubMed Central (United Kingdom)

In response to stress, cells start transcriptional and transcription-independent programs that can lead to adaptation or death. Here, we show that multiple inducers of autophagy, including nutrient...Full Text Available

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In vulnerable individuals, exposure to stressors can result in chronic disorders such as generalized anxiety disorder (GAD), major depressive disorder (MDD), and post-traumatic stress disorder (PTSD). The extended amygdala is critically implicated in mediating acute and chronic stress responsivity and anxiety-like behaviors. The bed nucleus of the stria terminalis (BNST), a subregion of the extended amygdala, serves as a relay of corticolimbic information to the paraventricular nucleus of the hypothalamus (PVN) to directly influence the stress response. To investigate the influence of the corticosteroid milieu and housing conditions on BNST function, adult C57Bl/6J were either acutely or chronically administered corticosterone (CORT, 25mg/kg in sesame oil) or vehicle (sesame oil) or were g...

International Nuclear Information System (INIS)

Magnetron sputter deposition was used to fabricate body centered cubic (bcc) and A-15 crystal structure W thin films. Previous work demonstrated that the as-deposited crystal structure of the films was dependent on the deposition parameters and that the formation of a metastable A-15 structure was favored over the thermodynamically stable bcc phase when the films contained a few atomic percent oxygen. However, the A-15 phase was shown to irreversibly transform into the bcc phase between 500 C and 650 C and that a significant decrease in the resistivity of the metallic films was measured after the transformation. The current investigation of 150 nm thick, sputter deposited A-15 and bcc tungsten thin films on silicon wafers consisted of a series of experiments in which the stress, resistivity and crystal structure of the films was measured as a function of temperatures cycles in a Flexus 2900 thin film stress measurement system. The as-deposited ...

UK PubMed Central (United Kingdom)

ContextCorticotropin-releasing hormone (CRH), through the hypothalamic pituitary adrenal (HPA) axis and other brain stress systems, is involved in the emotional dysregulation...Full Text Available

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Low residual stress silicon oxynitride thin films are investigated for use as a replacement for silicon dioxide (SiO{sub 2}) as sacrificial layer in surface micromachined microelectrical-mechanical systems (MEMS). It is observed that the level of residual stress in oxynitrides is a function of the nitrogen content in the film. MEMS film stacks are prepared using both SiO{sub 2} and oxynitride sacrificial layers. Wafer bow measurements indicate that wafers processed with oxynitride release layers are significantly flatter. Polycrystalline Si (poly-Si) cantilevers fabricated under the same conditions are observed to be flatter when processed with oxynitride rather than SiO{sub 2} sacrificial layers. These results are attributed to the lower post-processing residual stress of oxynitride compared to SiO{sub 2} and reduced thermal mismatch to poly-Si.

UK PubMed Central (United Kingdom)

Periventricular white matter injury (PWMI), is the leading cause of chronic neurologic injury among survivors of preterm birth. The hallmark of PWMI is hypomyelination and a lack of mature,...Full Text Available

UK PubMed Central (United Kingdom)

Obesity is characterized by the abnormal or excessive deposition of fat in the adipose tissue. Its consequences go far beyond adverse metabolic effects on health, causing an increase in oxidative stress,...Full Text Available

International Nuclear Information System (INIS)

... for mediating the effects of early adverse experiences since they are affected

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A new test methodology is described which allows access to loading rates that lie between split Hopkinson bar and shock-loading techniques. Gas gun experiments combined with velocity interferometry techniques have been used to experimentally determine the intermediate strain-rate loading behavior of Coors AD995 alumina and Cercom silicon-carbide rods. Graded-density materials have been used as impactors; thereby eliminating the tension states generated by the radial stress components during the loading phase. Results of these experiments demonstrate that the time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod. This allows access to intermediate loading rates over 5 x 10{sup 3}/s to a few times 10{sup 4}/s.

UK PubMed Central (United Kingdom)

Tetragonal ferroelectric/ferroelectric \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts}...Full Text Available

UK PubMed Central (United Kingdom)

Chaperones (stress proteins) are essential proteins to help the formation and maintenance of the proper conformation of other proteins and to promote cell survival after a large variety of environmental...Full Text Available

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We conduct the static and dynamic loading fracture experiments on magnesium alloy (AZ31B) under the equitable and inequitable biaxial stress. We process specimens as cross type with cracks. There are different kinds of cracks defined by their crack angles. By using a hydraulic high-speed biaxial experiment machine, we put the equitable and inequitable stresses on the specimen. We analyze results using the caustic method. The experiments reveal a few important results. There is negative correlation between the fracture toughness value and the plate thickness in the magnesium alloy sheet specimen. The fracture toughness value decrease in the case the crack has the angle different from the loading direction. The fracture toughness value decreases significantly under the inequitable biaxial stress. (orig.)

British Library Electronic Table of Contents (United Kingdom)

In this research, the interactive effect of grain and specimen sizes on the flow stress of sheet metal in microforming is investigated via the tensile test of pure copper and numerical modeling. Models based on different assumptions are proposed to analyze the size effect phenomenon. It is found that the flow stress decreases linearly with the decrease of the ratio of specimen to grain sizes. The grain boundary thickness decreases and its volume fraction increases with the decrease of grain size. The variation of grain boundary thickness is not proportional to the variation of grain size. Furthermore, the fraction of grain boundary increases with the strain and the ratio of specimen to grain sizes. Based on the FE simulation, it is found that the simulated flow stress, which is modeled bas...

British Library Electronic Table of Contents (United Kingdom)

This paper is concerned with the study of the Electrorheological RayleighTaylor instability (ERTI) at the interface between a densely packed saturated poorly conducting couple stress porous layer accelerated by a lighter poorly conducting couple stress fluid in a thin shell in the presence of a transverse electric field and laser radiation. A simple theory based on fully developed flow approximations is used to derive the dispersion relation for the growth rate of ERTI. The cutoff and the maximum wave numbers and the corresponding maximum frequencies are obtained. It is shown that the effects of couple stress parameter and the electric field reduce the growth rate considerably compared to a non-conducting fluid in the absence of an electric field. These are favorable to control the surface...

International Nuclear Information System (INIS)

... University, Fracture and Reliability Research Institute, Sendai, Miyagi (Japan)

International Nuclear Information System (INIS)

The effect of uniaxial tensile stress on intergranular corrosion (IGC) of AA2024-T3 was studied using the foil penetration technique. Standard ASTM G49 fixed-displacement jigs were modified to allow the use of sheet samples, which were then attached to an electrochemical cell as in the foil penetration setup. The time for IGC to penetrate samples of varying thickness was monitored. This method provides a new approach to bridge the gap between IGC and intergranular stress corrosion cracking (IGSCC). Samples with various orientations relative to the rolling direction were studied in 1.0 M NaCl at controlled anodic potentials. Potentiodynamic polarization measurements indicated that the two breakdown potentials typically observed for AA2024-T3 were lower for stressed samples than for unstressed samples, and the current at a given potential was higher. The penetration rate depended on potential and was higher for ...

International Nuclear Information System (INIS)

... Industry, Material Science Research Laboratory, Yokosuka, Kanagawa (Japan)

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138 unselected head tomographies of children by computer are reported and analysed. The major aspect stressed by the authors is the excellent precision of this radiological technique.

British Library Electronic Table of Contents (United Kingdom)

The residing fracture system and the prevailing in situ stresses have a significant impact on fluid flow and heat transfer in crystalline rocks. The long term response of fracture systems to changes in effective stresses, in particular the long term geo-mechanical effects of thermal stresses on reservoir characteristics is of particular interest to the geothermal industry.In this paper, a geothermal reservoir model is presented, in which a thermo-poroelastic finite element module is coupled to a fracture geomechanical module. This describes fracture closure as a function of effective stress and the changes in parameters, such as effective permeability, porosity and discrete fracture apertures. The novelty of this approach lies in its dynamic treatment of the characteristic properties of in...

Science.gov (United States)

reaching their ultimate compressive strength. Thus, when applying a lamina stress analysis in conjunction with a failure model, one must ...

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All power plant engineers face the problem of peak power demands. Pumped storage plants are used to generate peak load power by pumping up water utilizing off-peak energy of hydrothermal and thermonuclear plants. This is a reference to cover hydroelectric power generation with emphasis on engineering to meet peak power demands by means of pumped storage plants, tidal power plants, and low head power generation. Text covers hydrology, mechanical and electrical equipment, accessories such as penstocks and valves, and civil engineering considerations. Contains descriptions of several existing plants. Includes 200 diagrams and 50 photographs.

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As part of a coordinated program, AECL is developing a set of tools to aid with the prediction and management of steam generator performance. Although stress corrosion cracking (of Alloy 800) has not been detected in any operating steam generator, for life management it is necessary to develop mechanistic models to predict the conditions under which stress corrosion cracking is plausible. Therefore, constant extension rate tests were carried out for Alloy 800 under various steam generator crevice chemistry conditions at applied potentials. These tests were designed to evaluate the stress corrosion cracking susceptibility of Alloy 800 under CANDU( steam generator operating conditions. Based on the experimental results, the recommended electrochemical corrosion potential/pH zone for Alloy 800 determined by electrochemical polarization measurements was verified with the respect of stress corrosion cracking ...

International Nuclear Information System (INIS)

As part of a coordinated program, AECL is developing a set of tools to aid with the prediction and management of steam generator performance. Although stress corrosion cracking (of Alloy 800) has not been detected in any operating steam generator, for life management it is necessary to develop mechanistic models to predict the conditions under which stress corrosion cracking is plausible. Therefore, constant extension rate tests were carried out for Alloy 800 under various steam generator crevice chemistry conditions at applied potentials. These tests were designed to evaluate the stress corrosion cracking susceptibility of Alloy 800 under CANDU( steam generator operating conditions. Based on the experimental results, the recommended electrochemical corrosion potential/pH zone for Alloy 800 determined by electrochemical polarization measurements was verified with the respect of stress corrosion cracking ...

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The objectives of this project are to detect and characterize fractures in a naturally fractured tight gas reservoir, using surface seismic methods, borehole imaging logs, and in-situ stress field data. Further, the project aims to evaluate the various seismic methods as to their effectiveness in characterizing the fractures, and to formulate the optimum employment of the seismic methods as regards fracture characterization.