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1

COLD-SHOCKINJURY AND RAPID COLD HARDENING IN THE FLESHFLY SARCOPHAGACRASSIPALPIS'  

E-print Network

COLD-SHOCKINJURY AND RAPID COLD HARDENING IN THE FLESHFLY SARCOPHAGACRASSIPALPIS' CHENG.PINGCHEN,2 inuoiuedirihl;;p";*. Tharborh nondiapause-anddiapause-programmedfliei respondto short-termchillingindicates that survivebriefperiodsoiioi-t.,np".u,ur.. INTRODUCTION Cold shockis a form of cellularinjury gbse.rve{immediatelyafter rapid

Lee Jr., Richard E.

2

Fitness costs of rapid cold-hardening in Ceratitis capitata.  

PubMed

Rapid cold-hardening (RCH) is a unique form of phenotypic plasticity which confers survival advantages at low temperature. The fitness costs of RCH are generally poorly elucidated and are important to understanding the evolution of plastic physiology. This study examined whether RCH responses, induced by ecologically relevant diel temperature fluctuations, carry metabolic, survival, or fecundity costs. We predicted that potential costs in RCH would be manifested as differences in metabolic rate, fecundity, or survival in flies which have hardened versus those which have not, or flies that have experienced more RCH events would show greater costs than those which have experienced fewer events. One group of flies cooled to 10°C for 2 h for 11 consecutive days experienced daily RCH (Hardened), whereas the other group exposed to 15°C for the same 2-h period each day formed a Control group. Hardened flies had higher survival at -5°C for 2 h than control flies (69 ± 9% vs. 44 ± 19%,?P?= 0.04). Hardened flies showed no metabolic or fecundity costs, but had reduced average survival (P?= 0.0403). Thus, a major cost to repeated low temperature exposures in Ceratitis capitata is through direct mortality caused by chilling injury, although this appears not to be a direct cost of RCH. PMID:22220884

Basson, C Helene; Nyamukondiwa, Casper; Terblanche, John S

2012-01-01

3

Rapid cold hardening response in the predatory mite Neoseiulus californicus.  

PubMed

We investigated the rapid cold hardening (RCH) response in the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). On direct exposure, ?2 % of adult females survived -10 °C for 2 h. However, when acclimatized first at 5 °C for 1 h, 75 % of females survived. RCH could also be induced by acclimatization at 30 °C for 2 h or anoxia (oxygen-free nitrogen) for 1-2 h. All immature stages showed enhanced survival when acclimatized at 5 °C for 2 h before exposure to -10 °C. Acclimatization at 30 °C induced RCH only in eggs and deutonymphs, and anoxia was effective for eggs, larvae, and deutonymphs. The variability among immature stages may be attributed to the cost associated with the acclimatization treatments. Our findings suggest that RCH may promote the survival of N. californicus during unexpected changes in temperatures, and can be an important feature particularly when this natural enemy is introduced to non-native environments. PMID:24682616

Ghazy, Noureldin Abuelfadl; Amano, Hiroshi

2014-08-01

4

Anoxic stress and rapid cold hardening enhance cold tolerance of the migratory locust.  

PubMed

Anoxia and rapid cold hardening (RCH) can increase the cold tolerance of many animals. However, mechanisms underlying these two kinds of stresses remain unclear. In this study, we aimed to explore the relationship of acclimation to cold stress with acclimation to anoxic stress in the migratory locust, Locusta migratoria. RCH at 0°C for 3h promoted the survival of cold stress-exposed locusts. Anoxic hypercapnia (CO2 anoxic treatment) for 40 min exerted an effect similar to that of RCH. Anoxic hypercapnia within 1h can all promote the cold hardiness of locusts. We investigated the transcript levels of six heat shock protein (Hsp) genes, namely, Hsp20.5, Hsp20.6, Hsp20.7, Hsp40, Hsp70, and Hsp90. Four genes, namely, Hsp90, Hsp40, Hsp20.5, and Hsp20.7, showed differential responses to RCH and anoxic hypercapnia treatments. Under cold stress, locusts exposed to the two regimens showed different responses for Hsp90, Hsp20.5, and Hsp20.7. However, the varied responses disappeared after recovery from cold stress. Compared with the control group, the transcript levels of six Hsp genes were generally downregulated in locusts subjected to anoxic hypercapnia or/and RCH. These results indicate that anoxic stress and RCH have different mechanisms of regulating the transcription of Hsp family members even if the two treatments exerted similar effects on cold tolerance of the migratory locust. However, Hsps may not play a major role in the promotion of cold hardiness by the two treatments. PMID:25086202

Cui, Feng; Wang, Hongsheng; Zhang, Hanying; Kang, Le

2014-10-01

5

Mild desiccation rapidly increases freeze tolerance of the goldenrod gall fly, Eurosta solidaginis: evidence for drought-induced rapid cold-hardening.  

PubMed

Overwintering insects may experience extreme cold and desiccation stress. Both freezing and desiccation require cells to tolerate osmotic challenge as solutes become concentrated in the hemolymph. Not surprisingly, physiological responses to low temperature and desiccation share common features and may confer cross-tolerance against these stresses. Freeze-tolerant larvae of the goldenrod gall fly, Eurosta solidaginis (Diptera: Tephritidae), experience extremely dry and cold conditions in winter. To determine whether mild desiccation can improve freeze tolerance at organismal and cellular levels, we assessed survival, hemolymph osmolality and glycerol levels of control and desiccated larvae. Larvae that lost only 6-10% of their body mass, in as little as 6 h, had markedly higher levels of freeze tolerance. Mild, rapid desiccation increased freezing tolerance at -15°C in September-collected larvae (33.3±6.7 to 73.3±12%) and at -20°C in October-collected larvae (16.7±6.7 to 46.7±3.3%). Similarly, 6 h of desiccation improved in vivo survival by 17-43% in fat body, Malpighian tubule, salivary gland and tracheal cells at -20°C. Desiccation also enhanced intrinsic levels of cold tolerance in midgut cells frozen ex vivo (38.7±4.6 to 89.2±5.5%). Whereas hemolymph osmolality increased significantly with desiccation treatment from 544±16 to 720±26 mOsm, glycerol levels did not differ between control and desiccated groups. The rapidity with which a mild desiccation stress increased freeze tolerance closely resembles the rapid cold-hardening response, which occurs during brief sub-lethal chilling, and suggests that drought stress can induce rapid cold-hardening. PMID:22899523

Levis, Nicholas A; Yi, Shu-Xia; Lee, Richard E

2012-11-01

6

Strain hardening and orientation hardening\\/softening in cold rolled AA 5052 aluminum alloy  

Microsoft Academic Search

The tensile properties of cold rolled sheets were measured for the hot band and annealed hot band of AA 5052 aluminum alloy. The variation in yield strength with rolling true strain was used to represent the hardening rate of cold rolled sheets. The Taylor factor (M?) of cold rolled sheets in tension along the rolling direction was calculated based on

H. Yuan; J. Li; X. Y. Kong; C. C. Yu; Q. X. Yang; W. C. Liu

2008-01-01

7

Low-temperature tolerance and cold hardening of cacti  

SciTech Connect

Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over 300 m altitude in southern Wyoming, were quite cold tolerant. Relationships among tissue cold sensitivity, morphological features which protect the stems from low temperatures, and the occurrence of species in progressively colder regions were investigated. Differences in tissue cold sensitivity accounted for the approx. = 600 m higher elevational limit of Coryphantha vivipara var. rosea compared to the morphologically similar var. deserti in southern Nevada. In contrast, morphological differences alone could adequately explain the relative northern limits of the columnar cacti Carnegiea gigantea vs Stenocereus gummosus and the barrel cacti Ferocactus acanthodes vs. F. wislizenii in the southwestern United States, as previously indicated using a computer model. Cold hardening in response to decreasing day/night air temperatures was observed for 10 species. A decrease from 50/sup 0//40/sup 0/ to 10/sup 0//0/sup 0/ lowered by 4/sup 0/ the temperature at which the fraction of the chlorenchyma cells taking up stain was reduced 50% for both D. rhodacantha and T. candicans, with a half-time for the shift of approx. = 3 d. The tolerance of subzero temperatures and the ability to cold harden allow cacti to range into regions with considerable wintertime freezing.

Nobel, P.S.

1982-12-01

8

Low temperature tolerance and cold hardening of cacti  

SciTech Connect

Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over 3000 m altitude in southern Wyoming, were quite cold tolerant (50% inhibition of staining occurred from -17/sup 0/ to -20/sup 0/C), while O. bigelovii and O. ramosissima, which are restricted to much warmer habitats, were not very cold tolerant (50% inhibition from -4/sup 0/ to -7/sup 0/). Relationships among tissue cold sensitivity, morphological features which protect the stems from low temperatures, and the occurrence of species in progressively colder regions were investigated. Differences in tissue cold sensitivity accounted for the =600 m higher elevational limit of Coryphantha vivipara var. rosea compared to the morphologically similar var. deserti in southern Nevada. In contrast, morphological differences alone could adequately explain the relative northern limits of the columnar cacti Carnegiea gigantea vs. Stenocereus gummosus and the barrel cacti Ferocactus acanthodes vs. F. wislizenii in the southwestern United States, as previously indicated using a computer model. Differences in both morphology and tissue cold sensitivity apparently influenced the relative northern ranges of Lophocereus schottii with respect to the other columnar cacti and F. covillei with respect to the other barrel cacti, as well as the relative elevational range of Denmoza rhodacantha with respect to Trichocereus candicans in northcentral Argentina. Cold hardening in response to decreasing day/night air temperatures was observed for 10 species.

Nobel, P.S.

1982-12-01

9

Strain hardening of heavily cold-worked metals  

SciTech Connect

It is demonstrated that strain hardening in torsion cannot be correlated with axisymmetric deformation by the von Mises effective stress strain criterion. In fcc materials, the flow stress levels and strain hardening rates are typically lower in torsion and saturation, only at lower stress levels. In bcc iron, a low saturtion stress is observed for torsion, whereas linear hardening is observed for axisymmetric extension. Much of the discrepancy in flow curves can be explained by texture. It is demonstrated that a crystallographic effective stress-strain criterion based on evolving average Taylor factors provides the proper magnitude correction for torsional flow curves in fcc materials. The simple crystallographic analysis does not fully explain the hardening response following deformation path changes and multidirectional loading. 96 references, 42 figures.

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

1982-01-01

10

Solute Diffusion Characteristics of a Rapid Hardening Al-Cu-Mg Alloy during the Early Stages of Age Hardening  

NASA Astrophysics Data System (ADS)

The heat-transfer characteristics of a rapid hardening Al-1.1Cu-1.7Mg at. pct alloy during the early stages of age hardening have been tested, both by experiment and finite element modeling, for a typical laboratory-scale sample, and subsequently a maximum diffusion distance by random walk has been calculated for the solute atom species. It is found that due to small diffusion distances compared to the average dislocation loop interspacing, the dislocation-locking hardness mechanism is not likely, and rather, the cluster hardening model is more accurate.

Marceau, R. K. W.; Tsafnat, N.; Haley, D.; Ringer, S. P.

2010-08-01

11

Effects of induction hardening and prior cold work on a microalloyed medium carbon steel  

SciTech Connect

The torsional strength and microstructural response to induction hardening of a 10V45 steel with prior cold work was evaluated. The vanadium-microalloyed 1045 (10V45) steel was characterized in three conditions: as-hot-rolled, 18% cold-reduced, and 29% cold-reduced. Two of these evaluations, 10V45 as-hot-rolled and 10V45-18%, were subjected to stationary and progressive induction hardening to three nominal case depths: 2, 4, and 6 mm. All specimens were subsequently furnace tempered at 190 C for 1 h. The martensitic case microstructures contained residual lamellar carbides due to incomplete dissolution of the pearlitic carbides in the prior microstructure. Torsional overload strength, as measured by maximum torque capacity, is greatly increased by increasing case depth, and to a lesser extent by increasing prior cold work level. Maximum torque capacity ranges from 2520 to 3170 N[center dot]m, depending upon induction hardening processing. Changing induction hardening processing from stationary (single-shot) to progressive (scan) had little effect on torque capacity.

Cunningham, J.L. (American Axle and Manufacturing, Rochester Hills, MI (United States)); Medlin, D.J. (Timken Co., Canton, OH (United States)); Krauss, G. (Colorado School of Mines, Golden, CO (United States))

1999-08-01

12

Hardening behaviour law versus rigid perfectly plastic law: application to a cold forging tool steel  

Microsoft Academic Search

A hardening stress strain law is determined for the AISI M2 cold forging tool steel. The experimental part is based on the Brinell indentation test. The numerical part consists in the simulation of the Brinell indentation test under increasing load cases. For each load case, parameters of the behaviour law are adjusted in order to make the numerical diameter of

A Verleene; L Dubar; A Dubois; M Dubar; J Oudin

2002-01-01

13

Interactions between cold hardening and Microdochium nivaleinfection on expression of pathogenesis-related genes in winter wheat  

Microsoft Academic Search

Cold hardening induces snow mould resistance in cereals and grasses. The mechanism for this induced resistance is not fully understood. The accumulation of transcripts encoding sucrose synthase and the pathogenesis-related proteins (PR-proteins) chitinase, ?-1,3-glucanase, peroxidase and PR-1a were studied in hardened and non-hardened winter wheat at several time points after inoculation with the snow mouldMicrodochium nivale.Sucrose synthase was induced by

Å. Ergon; S. S. Klemsdal; A. M. Tronsmo

1998-01-01

14

Distortion Analysis in the Manufacturing of Cold-Drawn and Induction-Hardened Components  

NASA Astrophysics Data System (ADS)

In this investigation, a design of experiments analysis of distortion for a typical manufacturing process involving pre-straightening, cold drawing, and induction hardening of AISI 1045 cylindrical steel bars was carried out. A careful characterization of the material, including residual stress states and geometrical changes, was done for the different manufacturing steps. In order to identify effects and correlations on distortion behavior, the investigated variables included the batch influence, the combined drawing process itself with two different drawing angles and two different polishing and straightening (P.S.) angles, a stress relief treatment which was applied to a part of the samples, and finally induction hardening with two different surface hardening depths. Main and statistically significant effects on the distortion of the induction-hardened samples were found to be in this order: first, the interaction between the drawing angle and batch, then the interaction between drawing angles, and finally drawing angle and induction hardened layer. It was also found that the distortion potentials are transmitted from the drawing process to further manufacturing steps and, consequently, from one production site to the next.

Hirsch, Thomas Georg Karl; da Silva Rocha, Alexandre; Menezes Nunes, Rafael

2013-12-01

15

Influence of Cold-Hardening and Soil Matric Potential on Resistance to Speckled Snow Mold in Wheat  

Microsoft Academic Search

Nishio, Z., Iriki, N., Takata, K., Ito, M., Tabiki, T., and Murray, T. D. 2008. Influence of cold- hardening and soil matric potential on resistance to speckled snow mold in wheat. Plant Dis. 92:1021-1025. The influence of soil matric potential, cold-hardening temperature, and duration on resistance to speckled snow mold caused by Typhula ishikariensis in wheat was investigated. Six winter

Zenta Nishio; Norio Iriki; Kanenori Takata; Miwako Ito; Tadashi Tabiki; Timothy D. Murray

2008-01-01

16

Characterizing Hardening on Annealing of Cold-Rolled Aluminum AA3103 Strips  

NASA Astrophysics Data System (ADS)

AA3103 aluminum strips were cold rolled to various von Mises strains up to 4.7. In addition, two severely deformed conditions were obtained by one and four cycles of cold accumulated roll bonding subsequent to cold rolling to a strain of 4.2. For cases of subsequent annealing at 498 K (225 °C) for 10 minutes, an increase in the ultimate tensile strength was observed at the rolling strains of 1.7 and higher. Similar hardening is observed for a wide range of temperature-time combinations for temperatures greater than 423 K (150 °C). The yield stress is also increased by a few per cent during further cold rolling. The magnitude of the increase in strength on annealing increased with the increasing strain. Electron backscattered diffraction and transmission electron microscopy studies showed no significant changes in the high- or low-angle grain boundary spacings by this annealing. A systematic investigation on the roles played by Si and Mn was made with different homogenization treatments of AA3103 and of an AlSi alloy. Based on tensile tests, and differential scanning calorimetry and electrical conductivity measurements, it is concluded that Mn plays a major role. The exact mechanisms causing hardening on annealing are not identified, but through elimination of other explanations, it is suggested that some sort of clustering or precipitation mechanism is involved.

Govindaraj, Nagaraj Vinayagam; Bjørge, Ruben; Holmedal, Bjørn

2013-10-01

17

Influence of cold rolling degree and ageing treatments on the precipitation hardening of 2024 and 7075 alloys  

NASA Astrophysics Data System (ADS)

In the present work, the precipitation hardening of 2024 and 7075 aluminum alloys is investigated as a function of cold rolling degree, ageing time and temperature using Vickers microhardness measurements and differential scanning calorimetry (DSC). It is found that a variation in such parameters can improve the hardness and plays an important role in the precipitation hardening process. At specific ageing temperature, the large cold rolled 7075 alloy exhibits two peaks of hardness. Moreover, for both alloys, the increment of hardness during ageing decreases with increasing the cold rolling degree. While in some cases microhardness measurements give impression that the precipitation reaction is slowed down by deformation, DSC analysis indicates that the precipitation is much accelerated since only a slight deformation decreases strongly the temperatures of reactions. However, the degree of cold rolling does not play a crucial role.

Naimi, A.; Yousfi, H.; Trari, M.

2013-08-01

18

Finite Element Calculation of Residual Stress and Cold-work Hardening Induced in Inconel 718 by Low Plasticity Burnishing  

Microsoft Academic Search

Low Plasticity Burnishing (LPB), a mechanical surface enhancement technology was developed to produce a deep layer of highly compressive residual stress comparable to laser shot peening, but with minimal cold-work hardening, LPB produces the most thermally stable compression to hot sections of gas turbine engines made by superalloy like Inconel 718. Literatures detailing the experimental effects of LPB are comprehensive,

Feng-Lei Li; Wei Xia; Zhao-Yao Zhou

2010-01-01

19

Rapid evolution of cold tolerance in stickleback.  

PubMed

Climate change is predicted to lead to increased average temperatures and greater intensity and frequency of high and low temperature extremes, but the evolutionary consequences for biological communities are not well understood. Studies of adaptive evolution of temperature tolerance have typically involved correlative analyses of natural populations or artificial selection experiments in the laboratory. Field experiments are required to provide estimates of the timing and strength of natural selection, enhance understanding of the genetics of adaptation and yield insights into the mechanisms driving evolutionary change. Here, we report the experimental evolution of cold tolerance in natural populations of threespine stickleback fish (Gasterosteus aculeatus). We show that freshwater sticklebacks are able to tolerate lower minimum temperatures than marine sticklebacks and that this difference is heritable. We transplanted marine sticklebacks to freshwater ponds and measured the rate of evolution after three generations in this environment. Cold tolerance evolved at a rate of 0.63 haldanes to a value 2.5°C lower than that of the ancestral population, matching values found in wild freshwater populations. Our results suggest that cold tolerance is under strong selection and that marine sticklebacks carry sufficient genetic variation to adapt to changes in temperature over remarkably short time scales. PMID:20685715

Barrett, Rowan D H; Paccard, Antoine; Healy, Timothy M; Bergek, Sara; Schulte, Patricia M; Schluter, Dolph; Rogers, Sean M

2011-01-22

20

Rapid desiccation hardening changes the cuticular hydrocarbon profile of Drosophila melanogaster.  

PubMed

The success of insects in terrestrial environments is due in large part to their ability to resist desiccation stress. Since the majority of water is lost across the cuticle, a relatively water-impermeable cuticle is a major component of insect desiccation resistance. Cuticular permeability is affected by the properties and mixing effects of component hydrocarbons, and changes in cuticular hydrocarbons can affect desiccation tolerance. A pre-exposure to a mild desiccation stress increases duration of desiccation survival in adult female Drosophila melanogaster, via a decrease in cuticular permeability. To test whether this acute response to desiccation stress is due to a change in cuticular hydrocarbons, we treated male and female D. melanogaster to a rapid desiccation hardening (RDH) treatment and used gas chromatography to examine the effects on cuticular hydrocarbon composition. RDH led to reduced proportions of unsaturated and methylated hydrocarbons compared to controls in females, but although RDH modified the cuticular hydrocarbon profile in males, there was no coordinated pattern. These data suggest that the phenomenon of RDH leading to reduced cuticular water loss occurs via an acute change in cuticular hydrocarbons that enhances desiccation tolerance in female, but not male, D. melanogaster. PMID:25460832

Stinziano, Joseph R; Sové, Richard J; Rundle, Howard D; Sinclair, Brent J

2015-02-01

21

A new cold-induced alfalfa gene is associated with enhanced hardening at subzero temperature.  

PubMed Central

When alfalfa (Medicago sativa L. cv Apica) plants grown at room temperature are transferred to 2 degrees C, the temperature at which 50% of the plants fail to survive (LT50) decreases from -6 to -14 degrees C during the first 2 weeks but then increases to -9 degrees C during the subsequent 2 weeks. However, when plants are kept for 2 weeks at 2 degrees C and then transferred to -2 degrees C for another two weeks, the LT50 declines to -16 degrees C. These changes in freezing tolerance are paralleled by changes in transcript levels of cas15 (cold acclimation-specific gene encoding a 14.5-kD protein), a cold-induced gene. Cold-activation of cas15 occurs even when protein synthesis is inhibited by more than 90%, suggesting that cold-initiated events up to and including the accumulation of cas15 transcripts depend on preexisting gene products. cas15 shows little homology to any known gene at the nucleotide or amino acid level. The deduced polypeptide (CAS15) of 14.5 kD contains four repeats of a decapeptide motif and possesses a bipartite sequence domain at the carboxy terminus with homology to the reported nuclear-targeting signal sequences. Although the relative amount of cas15 DNA as a fraction of the total genomic DNA is similar in cultivars with different degrees of freezing tolerance, its organization in the genome is different. The possible role of cas15 in the development of cold-induced freezing tolerance is discussed. PMID:8278537

Monroy, A F; Castonguay, Y; Laberge, S; Sarhan, F; Vezina, L P; Dhindsa, R S

1993-01-01

22

Cold hardening processes in the Antarctic springtail, Cryptopygus antarcticus: clues from a microarray.  

PubMed

The physiology of the Antarctic microarthropod, Cryptopygus antarcticus, has been well studied, particularly with regard to its ability to withstand low winter temperatures. However, the molecular mechanisms underlying this phenomenon are still poorly understood. 1180 sequences (Expressed Sequence Tags or ESTs) were generated and analysed, from populations of C. antarcticus. This represents the first publicly available sequence data for this species. A sub-set (672 clones) were used to generate a small microarray to examine the differences in gene expression between summer acclimated cold tolerant and non-cold tolerant springtails. Although 60% of the clones showed no sequence similarity to annotated genes in the datasets, of those where putative function could be inferred via database homology, there was a clear pattern of up-regulation of structural proteins being associated with the cold tolerant group. These structural proteins mainly comprised cuticle proteins and provide support for the recent theory that summer SCP variation within Collembola species could be a consequence of moulting, with moulting population having lowered SCPs. PMID:18703067

Pura?, Jelena; Burns, Gavin; Thorne, Michael A S; Grubor-Lajsi?, Gordana; Worland, M Roger; Clark, Melody S

2008-09-01

23

RAPID SOLUTION HARDENING AT ELEVATED TEMPERATURES BY SUBSTITUTIONAL Re ALLOYING IN  

E-print Network

using silicon nitride reinforcement [4] or alloying with Al [5]. Deformation studies, in compression September 1999) AbstractÐThe mechanical properties of solidi®cation processed polycrystalline MoSi2 is found to be a potent solid solution hardening addition to C11b MoSi2 at temperatures up to 16008C

24

Surface hardening of steel by boriding in a cold rf plasma  

NASA Technical Reports Server (NTRS)

Scanning electron spectroscopy, X-ray diffractometry, Auger electron spectroscopy, and microhardness measurements, are used to study the surfaces of 4340-steel samples that have been borided in a cold RF plasma which had been initiated in a gas mixture of 2.7 percent diborane in Ar. As a result of the dislocation of the diborane in the plasma, boron is deposited on the surface of the steel substrate and two crystalline phases, tetragonal Fe2B and orthorhombic FeB, are formed. The formation of boride phases then increases the surface microhardness from 2650 MPa to a maximum value of 7740 MPa.

Finberg, I.; Avni, R.; Grill, A.; Spalvins, T.; Buckley, D. H.

1985-01-01

25

Proteins Involved in Distinct Phases of Cold Hardening Process in Frost Resistant Winter Barley (Hordeum vulgare L.) cv Luxor  

PubMed Central

Winter barley is an economically important cereal crop grown in higher latitudes and altitudes where low temperatures represent an important environmental constraint limiting crop productivity. In this study changes in proteome of leaves and crowns in a frost tolerant winter barley cv. Luxor in relation to short and long term periods of cold followed by a brief frost treatment were studied in order to disclose proteins responsible for the cold hardening process in distinct plant tissues. The mentioned changes have been monitored using two dimensional difference gel electrophoresis (2D-DIGE) with subsequent peptide-mapping protein identification. Regarding approximately 600–700 distinct protein spots detected on 2D gels, there has been found at least a two-fold change after exposure to low temperatures in about 10% of proteins in leaves and 13% of proteins in crowns. Protein and nitrogen metabolic processes have been influenced by low temperature to a similar extent in both tissues while catabolism, carbohydrate metabolism and proteins involved in stress response have been more affected in crowns than in leaves. The range of changes in protein abundance was generally higher in leaves and chloroplast proteins were frequently affected which suggests a priority to protect photosynthetic apparatus. Overall, our data proved existence of slightly different response strategies to low temperature stress in crowns and leaves, i.e., tissues with different biological role. Moreover, there have been found several proteins with large increase in accumulation, e.g., 33 kDa oxygen evolving protein of photosystem II in leaves and “enhanced disease susceptibility 1” in crowns; these proteins might have potential to indicate an enhanced level of frost tolerance in barley. PMID:23584021

Hlavá?ková, Iva; Vítámvás, Pavel; Šantr??ek, Ji?í; Kosová, Klára; Zelenková, Sylva; Prášil, Ilja Tom; Ovesná, Jaroslava; Hynek, Radovan; Kodí?ek, Milan

2013-01-01

26

TEM Studies of Boron-Modified 17Cr-7Ni Precipitation-Hardenable Stainless Steel via Rapid Solidification Route  

NASA Astrophysics Data System (ADS)

Commercial grade 17Cr-7Ni precipitation-hardenable stainless steel has been modified by adding boron in the range 0.45 to 1.8 wt pct and using the chill block melt-spinning technique of rapid solidification (RS). Application of RS has been found to increase the solid solubility of boron and hardness of 17Cr-7Ni precipitation-hardenable stainless steel. The hardness of the boron-modified rapidly solidified alloys has been found to increase up to ~280 pct after isochronal aging to peak hardness. A TEM study has been carried out to understand the aging behavior. The presence of M23(B,C)6 and M2(B,C) borocarbides and epsilon-carbide in the matrix of austenite and ferrite with a change in heat treatment temperature has been observed. A new equation for Creq is also developed which includes the boron factor on ferrite phase stability. The study also emphasizes that aluminum only takes part in ferrite phase stabilization and remains in the solution.

Gupta, Ankur; Bhargava, A. K.; Tewari, R.; Tiwari, A. N.

2013-09-01

27

Promising methods of surface hardening for titanium alloys and steels with rapid heating  

SciTech Connect

The results of electrical and electron beam heat treatment, thermal diffusion hardening, short-term electron beam and gas heat treatment flashing, and the effect of these processes on metallized coatings were studied. During electron beam heating a range of structural changes were studied: morphology of the components, alloying distribution, hardness, and microstresses in titanium alloys VT9, VT6, and VT15, and tool steels U8, U10, Kh12M and Kh12F1. These methods were found to reduce inclusions and nonuniform alloying distribution and rebuild surface structure with fine block formation and electron beam adhesive strength improved.

Shipko, A.A.

1988-03-01

28

Effect of heat treatment and cold hardening by shot blasting on the fine structure and properties of alloy AL19  

Microsoft Academic Search

1.The increase of the fatigue strength of alloy AL19 after shot hardening is due to strain aging, compressive stresses, and refining of the substructure.2.We determined the optimal shot hardening treatment for the thermally aged, alloy AL19 to produce the highest strength characteristics.

A. S. Shigarev; E. A. Lalayan

1968-01-01

29

Rapid uplift of nonmethane hydrocarbons in a cold front over central Europe  

E-print Network

Rapid uplift of nonmethane hydrocarbons in a cold front over central Europe R. M. Purvis,1 A. C between the PBL and FT was observed for all short and medium lifetime hydrocarbons (e.g., average iso of a cold front, a rapid uplift of reactive carbon from the boundary layer to the mid free troposphere

Hoskins, Brian

30

Effect of Cold Hardening on the Components of Respiratory Decarboxylation in the Light and in the Dark in Leaves of Winter Rye.  

PubMed Central

In the dark, all decarboxylation reactions are associated with the oxidase reactions of mitochondrial electron transport. In the light, photorespiration is also active in photosynthetic cells. In winter rye (Secale cereale L.), cold hardening resulted in a 2-fold increase in the rate of dark respiratory CO2 release from leaves compared with nonhardened (NH) controls. However, in the light, NH and cold-hardened (CH) leaves had comparable rates of oxidase decarboxylation and total intracellular decarboxylation. Furthermore, whereas CH leaves showed similar rates of total oxidase decarboxylation in the dark and light, NH leaves showed a 2-fold increase in total oxidase activity in the light compared with the dark. Light suppressed oxidase decarboxylation of end products of photosynthesis 2-fold in NH leaves and 3-fold in CH leaves in air. However, in high-CO2, light did not suppress the oxidase decarboxylation of end products. Thus, the decrease in oxidase decarboxylation of end products observed in the light and in air reflected glycolate-cycle-related inhibition of tricarboxylic acid cycle activity. We also showed that the glycolate cycle was involved in the decarboxylation of the end products of photosynthesis in both NH and CH leaves, suggesting a flow of fixed carbon out of the starch pool in the light. PMID:12226322

Hurry, V.; Keerberg, O.; Parnik, T.; Oquist, G.; Gardestrom, P.

1996-01-01

31

Causes and the methods of correction of the defects ``transverse ribbing'' and ``work-hardened bands'' on the surface of cold-rolled autobody sheets  

NASA Astrophysics Data System (ADS)

A surface defect in the form of parallel alternating dark and bright bands located across the rolling direction appear periodically upon cold rolling of thin-sheet steel intended for the face parts of cars. This defect is known as transverse ribbing and is visually observed upon rolling. The difference in the dark- and bright-band thicknesses can be determined with a micrometer. A similar but finer defect in the form of work-hardened bands has recently been detected. It is only observed after the sheet surface is processed with hones. In this case, the difference in the band thicknesses cannot be determined with a micrometer. A theory is proposed to explain the causes of the appearance of these defects, and methods for their correction are developed and tested on a commercial rolling mill.

Garber, E. A.; Pavlov, S. I.; Kuznetsov, V. V.; Timofeeva, M. A.; Traino, A. I.

2009-02-01

32

Rapid remobilization of magmatic crystals kept in cold storage.  

PubMed

The processes involved in the formation and storage of magma within the Earth's upper crust are of fundamental importance to volcanology. Many volcanic eruptions, including some of the largest, result from the eruption of components stored for tens to hundreds of thousands of years before eruption. Although the physical conditions of magma storage and remobilization are of paramount importance for understanding volcanic processes, they remain relatively poorly known. Eruptions of crystal-rich magma are often suggested to require the mobilization of magma stored at near-solidus conditions; however, accumulation of significant eruptible magma volumes has also been argued to require extended storage of magma at higher temperatures. What has been lacking in this debate is clear observational evidence linking the thermal (and therefore physical) conditions within a magma reservoir to timescales of storage-that is, thermal histories. Here we present a method of constraining such thermal histories by combining timescales derived from uranium-series disequilibria, crystal sizes and trace-element zoning in crystals. At Mount Hood (Oregon, USA), only a small fraction of the total magma storage duration (at most 12 per cent and probably much less than 1 per cent) has been spent at temperatures above the critical crystallinity (40-50 per cent) at which magma is easily mobilized. Partial data sets for other volcanoes also suggest that similar conditions of magma storage are widespread and therefore that rapid mobilization of magmas stored at near-solidus temperatures is common. Magma storage at low temperatures indicates that, although thermobarometry calculations based on mineral compositions may record the conditions of crystallization, they are unlikely to reflect the conditions of most of the time that the magma is stored. Our results also suggest that largely liquid magma bodies that can be imaged geophysically will be ephemeral features and therefore their detection could indicate imminent eruption. PMID:24531766

Cooper, Kari M; Kent, Adam J R

2014-02-27

33

Precipitation hardening  

NASA Astrophysics Data System (ADS)

The topic of precipitation hardening is critically reviewed, emphasizing the influence of precipitates on the CRSS or yield strength of aged alloys. Recent progress in understanding the statistics of dislocation-precipitate interactions is highlighted. It is shown that Pythagorean superposition for strengthening by random mixtures of localized obstacles of different strengths is rigorously obeyed in the limit of very weak obstacles; this had been known previously as a result of computer simulation experiments. Some experimental data are discussed in light of this prediction. All of the currently viable mechanisms of precipitation hardening are reviewed. It is demonstrated that all versions of the theory of coherency hardening are woefully inadequate, while the theory of order hardening is capable of accurately predicting the contribution of ?' precipitates to the CRSS of aged Ni-Al alloys. It is also convincingly shown that a new theory based on computer simulation experiments of the motion of dislocations through arrays of obstacles having a finite range of interaction cannot explain these same data, and is of doubtful validity in other instances for which its success has been proclaimed. A new theory of hardening by spinodal decomposition is proposed. It is based on the statistics of interaction between dislocations and diffuse attractive obstacles, and is shown to be in very good quantitative agreement with much of the limited data available. Some of the problems that remain to be addressed and solved are discussed.

Ardell, A. J.

1985-12-01

34

Rapid assimilation of yolk enhances growth and development of lizard embryos from a cold environment.  

PubMed

Selection for rapid growth and development in cold environments results in a geographic pattern known as countergradient variation. The eastern fence lizard, Sceloporus undulatus, exhibits countergradient variation in embryonic growth and development along latitudinal clines. To identify the proximate causes of countergradient variation, we compared the energy budgets of embryos from a cold environment (Virginia) and a warm environment (South Carolina) during development at a realistic thermal cycle. The difference in mean egg size between populations was controlled by removing yolk from large eggs and performing a sham manipulation on other eggs. Respiration was measured every 4 days throughout 48 days of incubation. After this period, eggs were dissected and the energy contents of embryos and yolk were determined by calorimetry. As expected from previous experiments, embryos from Virginia reached a more advanced stage of development and deposited more energy within tissues than embryos from South Carolina. The greater absorption of yolk by embryos from Virginia was associated with a higher rate of respiration. Assimilation of yolk by rapidly growing embryos could reduce growth or survival after hatching. Such costs might explain the maintenance of countergradient variation in S. undulatus. PMID:17872995

Storm, Melissa A; Angilletta, Michael J

2007-10-01

35

Dispersion strengthening of precipitation hardened Al-Cu-Mg alloys prepared by rapid solidification and mechanical alloying  

NASA Technical Reports Server (NTRS)

Several Al-4Cu-1Mg-1.5Fe-0.75Ce alloys have been processed from either rapidly solidified or mechanically alloyed powder using various vacuum degassing parameters and consolidation techniques. Strengthening by the fine subgrains, grains, and the dispersoids individually or in combination is more effective when the alloys contain shearable precipitates; consequently, the strength of the alloys is higher in the naturally aged rather than the artificially aged condition. The strengths of the mechanically alloyed variants are greater than those produced from prealloyed powder. Properties and microstructural features of these dispersion strengthened alloys are discussed in regards to their processing histories.

Gilman, P. S.; Sankaran, K. K.

1988-01-01

36

Comparative Study of Hardening Mechanisms During Aging of a 304 Stainless Steel Containing ?'-Martensite  

NASA Astrophysics Data System (ADS)

Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of ?'-martensite, hardening of ?'-martensite, and hardening of deformed austenite. The increased amount of ?'-martensite at an aging temperature of 450 °C confirmed the additional formation of ?'-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both ?'-martensite and austenite phases with aging temperature proved that hardening of both ?'-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an ?'-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels.

Jeong, S. W.; Kang, U. G.; Choi, J. Y.; Nam, W. J.

2012-09-01

37

Surface Fatigue Resistance with Induction Hardening  

NASA Technical Reports Server (NTRS)

Induction hardening has been used for some years to harden the surface and improve the strength and service life of gears and other components. Many applications that employ induction hardening require a relatively long time to finish the hardening process and controlling the hardness of the surface layer and its depth often was a problem. Other surface hardening methods, ie., carbonizing, take a very long time and tend to cause deformations of the toothing, whose elimination requires supplementary finishing work. In double-frequency induction hardening, one uses a low frequency for the preheating of the toothed wheel and a much higher frequency for the purpose of rapidly heating the surface by way of surface hardening.

Townsend, Dennis; Turza, Alan; Chapman, Mike

1996-01-01

38

Effects of a Short-Term Shift to Low Temperature and of Long-Term Cold Hardening on Photosynthesis and Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase and Sucrose Phosphate Synthase Activity in Leaves of Winter Rye (Secale cereale L.).  

PubMed Central

The effect of a short-term (hours) shift to low temperature (5[deg]C) and long-term (months) cold hardening on photosynthesis and carbon metabolism was studied in winter rye (Secale cereale L. cv Musketeer). Cold-hardened plants grown at 5[deg]C exhibited 25% higher in situ CO2 exchange rates than nonhardened plants grown at 24[deg]C. Cold-hardened plants maintained these high rates throughout the day, in contrast to nonhardened plants, which showed a gradual decline in photosynthesis after 3 h. Associated with the increase in photosynthetic capacity following cold hardening was an increase in ribulose-1,5-bisphosphate carboxylase/oxygenase and sucrose phosphate synthase activity and 3- to 4-fold increases in the pools of associated metabolites. Leaves of nonhardened plants shifted overnight to 5[deg]C required 9 h in the light at 5[deg]C before maximum rates of photosynthesis were reached. The gradual increase in photosynthesis in leaves shifted to 5[deg]C was correlated with a sharp decline in the 3-phosphoglycerate/triose phosphate ratio and by an increase in the ribulose bisphosphate/3-phosphoglycerate ratio, indicating the gradual easing of aninorganic phosphate-mediated feedback inhibition on photo-synthesis. We suggest that the strong recovery of photosynthesis in winter rye following cold hardening indicates that the buildup of photosynthetic enzymes, as well as those involved in sucrose synthesis, is an adaptive response that enables these plants to maximize the production of sugars that have both cryoprotective and storage functions that are critical to the performance of these cultivars during over-wintering. PMID:12232378

Hurry, V. M.; Malmberg, G.; Gardestrom, P.; Oquist, G.

1994-01-01

39

Effect of the Antimitotic Agent Oryzalin and Ca 2+ on the Permeability of the Plasma Membranes of Cold-Hardened Plants  

Microsoft Academic Search

An integral characteristic of the structure and function of membranes is their permeability, which is assessed by electrolyte efflux from tissues. This parameter is used for estimation of the membrane damage [1, 2]. An increase in the plasma-membrane fluidity after exposure to cold is due to microtubule depolymerization [3] and release of intramembrane particles bound to the matrix components [4].

E. V. Asafova; L. P. Khokhlova; I. L. Volovnik; E. E. Makarova

2001-01-01

40

Cold acclimation induces rapid and dynamic changes in freeze tolerance mechanisms in the cryophile Deschampsia antarctica E. Desv.  

PubMed

The cryophilic Antarctic hair grass, Deschampsia antarctica E. Desv., one of two higher plants indigenous to Antarctica, represents a unique resource for the study of freeze tolerance mechanisms. We have previously characterized a multi-gene family in D. antarctica encoding ice recrystallization inhibition proteins (IRIPs) whose transcript levels are responsive to cold acclimation, and whose products confer ice recrystallization inhibition (RI) activity that can account for activity seen in cold acclimated plants. We used molecular and physiological analyses to investigate temporal responses of D. antarctica to cold acclimation and de-acclimation, and sub-zero acclimation. Quantitative profiling revealed that IRIP transcript levels significantly increased and decreased within hours of cold acclimation and de-acclimation, respectively, becoming up to 1000-fold more abundant in fully acclimated plants. Western analysis detected three major immuno-reactive bands whose pattern of accumulation mirrored that of transcript. These data correlated with the onset and decline of RI activity in acclimated and de-acclimated leaves. Plant survival-based testing revealed that cold acclimation enhanced freeze tolerance by 5 °C within 4 d, and that sub-zero acclimation conferred an additional 3 °C of tolerance. Thus, D. antarctica is highly responsive to temperature fluctuations, able to rapidly deploy IRIP based RI activity and enhance its freeze tolerance. PMID:22070607

Chew, Orinda; Lelean, Suzanne; John, Ulrik P; Spangenberg, German C

2012-04-01

41

A Method for Rapid Measurement of Heat or Cold Resistance of Small R. B. Huey; W. D. Crill; J. G. Kingsolver; K. E. Weber  

E-print Network

A Method for Rapid Measurement of Heat or Cold Resistance of Small Insects R. B. Huey; W. D. Crill British Ecological Society. Your use of the JSTOR archive indicatesyour acceptanceof JSTOR's Terms measurement of heat or cold resistance of small insects R. B. HUEY, W. D. CRILL, J. G. KINGSOLVER and K. E

Huey, Raymond B.

42

Long-Term Cold Acclimation Extends Survival Time at 0°C and Modifies the Metabolomic Profiles of the Larvae of the Fruit Fly Drosophila melanogaster  

Microsoft Academic Search

BackgroundDrosophila melanogaster is a chill-susceptible insect. Previous studies on this fly focused on acute direct chilling injury during cold shock and showed that lower lethal temperature (LLT, approximately ?5°C) exhibits relatively low plasticity and that acclimations, both rapid cold hardening (RCH) and long-term cold acclimation, shift the LLT by only a few degrees at the maximum.Principal FindingsWe found that long-term

Vladimír Kostál; Jaroslava Korbelová; Jan Rozsypal; Helena Zahradnícková; Jana Cimlová; Ales Tomcala; Petr Simek; Amit Singh

2011-01-01

43

How insects survive the cold: molecular mechanisms—a review  

Microsoft Academic Search

Insects vary considerably in their ability to survive low temperatures. The tractability of these organisms to experimentation\\u000a has lead to considerable physiology-based work investigating both the variability between species and the actual mechanisms\\u000a themselves. This has highlighted a range of strategies including freeze tolerance, freeze avoidance, protective dehydration\\u000a and rapid cold hardening, which are often associated with the production of

Melody S. Clark; M. Roger Worland

2008-01-01

44

High speed end milling of hardened AISI D2 tool steel (?58 HRC)  

Microsoft Academic Search

Tool steels conforming to AISI group D are used widely in the manufacture of blanking and cold-forming dies, on account of their excellent wear resistance and deep hardening characteristics. The present paper gives details of machining experiments with hardened AISI D2 cold work tool steel (?58HRC) using indexable insert ball nose end mills employing carbide and cermet tools, and solid

P Koshy; R. C Dewes; D. K Aspinwall

2002-01-01

45

Rapid determination of immunoglobulin G concentration in cold ethanol precipitation process of raw plasma with near-infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy (NIRS) is known to be a powerful analytical tool in process monitoring. The feasibility of NIRS was investigated for determination of immunoglobulin G (IgG) in raw plasma cold ethanol precipitation process. Partial least squares (PLS) was used to develop regression model for 63 samples between spectra and reference data measured with a UV spectrophotometer. Three different variable selection methods, including correlation coefficient method, interval partial least squares (iPLS) and successive projection algorithm (SPA), were performed and compared with models based on all the variables. The values of Rc and root mean square error of cross validation (RMSECV) produced by the best model for the calibration set were 0.9599 and 0.6135 g/L, respectively. While for the validation set, the values of Rp and root mean square error of prediction (RMSEP) were 0.9577 and 0.4913 g/L, respectively. The results of this paper demonstrated that NIRS could be a feasible alternative approach for rapid determination of IgG in the cold ethanol precipitation process and can be used as a PAT tool in the future.

Zhang, Hui; Liu, Aihua; Zang, Hengchang; Li, Hu; Jiang, Wei; Li, Lian; Wang, Jinfeng

2013-12-01

46

Rapid determination of immunoglobulin G concentration in cold ethanol precipitation process of raw plasma with near-infrared spectroscopy.  

PubMed

Near-infrared spectroscopy (NIRS) is known to be a powerful analytical tool in process monitoring. The feasibility of NIRS was investigated for determination of immunoglobulin G (IgG) in raw plasma cold ethanol precipitation process. Partial least squares (PLS) was used to develop regression model for 63 samples between spectra and reference data measured with a UV spectrophotometer. Three different variable selection methods, including correlation coefficient method, interval partial least squares (iPLS) and successive projection algorithm (SPA), were performed and compared with models based on all the variables. The values of Rc and root mean square error of cross validation (RMSECV) produced by the best model for the calibration set were 0.9599 and 0.6135 g/L, respectively. While for the validation set, the values of Rp and root mean square error of prediction (RMSEP) were 0.9577 and 0.4913 g/L, respectively. The results of this paper demonstrated that NIRS could be a feasible alternative approach for rapid determination of IgG in the cold ethanol precipitation process and can be used as a PAT tool in the future. PMID:23973581

Zhang, Hui; Liu, Aihua; Zang, Hengchang; Li, Hu; Jiang, Wei; Li, Lian; Wang, Jinfeng

2013-12-01

47

Cold nuclear matter physics at forward rapidities from d+Au collisions in PHENIX  

SciTech Connect

We present measurements by the PHENIX experiment at the RHIC of di-hadron pair production in d +Au collisions where the particles in the pair are varied across a wide range of pseudorapidity, out to {eta} = 3.8. With di-hadrons, varying the p{sub T} and rapidity of the particles in the di-hadron pair allows studying any effects as a function of partonic x in the nucleus. These di-hadron measurements might probe down to parton momentum fractions x {approx} 10{sup -3} in the gold nucleus, where the interesting possibility of observing gluon saturation effects at the RHIC is the greatest. Our measurements show that the correlated yield of back-to-back pairs in d + Au collisions is suppressed by up to an order of magnitude relative to p+p collisions, and increases with greater nuclear path thickness and with a selection for lower x in the Au nucleus.

Chiu M.; PHENIX Collaboration

2011-11-10

48

Correlation between Cold- and Drought-Induced Frost Hardiness in Winter Wheat and Rye Varieties.  

PubMed

Exposure of six wheat (Triticum aestivum L.) and one rye (Secale cereale L.) cultivar to 40% relative humidity for 24 hours induced the same degree of freezing tolerance in seedling epicotyls as did cold conditioning for 4 weeks at 2 degrees C.Frost hardiness varietal relationships were the same in desiccation-stressed and cold-hardened seedlings. Drought stress could, therefore, be used as a rapid and simple method for inducing frost hardiness in seedling shoots in replacement of cold conditioning. PMID:16662170

Cloutier, Y; Siminovitch, D

1982-01-01

49

Rapid Multiplex PCR Assay To Identify Respiratory Viral Pathogens: Moving Forward Diagnosing The Common Cold  

PubMed Central

Upper respiratory tract infections (URIs) can be a serious burden to the healthcare system. The majority of URIs are viral in etiology, but definitive diagnosis can prove difficult due to frequently overlapping clinical presentations of viral and bacterial infections, and the variable sensitivity, and lengthy turn-around time of viral culture. We tested new automated nested multiplex PCR technology, the FilmArray® system, in the TAMC department of clinical investigations, to determine the feasibility of replacing the standard viral culture with a rapid turn-around system. We conducted a feasibility study using a single-blinded comparison study, comparing PCR results with archived viral culture results from a convenience sample of cryopreserved archived nasopharyngeal swabs from acutely ill ED patients who presented with complaints of URI symptoms. A total of 61 archived samples were processed. Viral culture had previously identified 31 positive specimens from these samples. The automated nested multiplex PCR detected 38 positive samples. In total, PCR was 94.5% concordant with the previously positive viral culture results. However, PCR was only 63.4% concordant with the negative viral culture results, owing to PCR detection of 11 additional viral pathogens not recovered on viral culture. The average time to process a sample was 75 minutes. We determined that an automated nested multiplex PCR is a feasible alternative to viral culture in an acute clinical setting. We were able to detect at least 94.5% as many viral pathogens as viral culture is able to identify, with a faster turn-around time. PMID:24052914

Gordon, Sarah M; Elegino-Steffens, Diane U; Agee, Willie; Barnhill, Jason; Hsue, Gunther

2013-01-01

50

An Anisotropic Hardening Model for Springback Prediction  

NASA Astrophysics Data System (ADS)

As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test.

Zeng, Danielle; Xia, Z. Cedric

2005-08-01

51

Cold worked ferritic alloys and components  

DOEpatents

This invention relates to liquid metal fast breeder reactor and steam generator precipitation hardening fully ferritic alloy components which have a microstructure substantially free of the primary precipitation hardening phase while having cells or arrays of dislocations of varying population densities. It also relates to the process by which these components are produced, which entails solution treating the alloy followed by a final cold working step. In this condition, the first significant precipitation hardening of the component occurs during high temperature use.

Korenko, Michael K. (Wexford, PA)

1984-01-01

52

Precipitation hardening austenitic superalloys  

DOEpatents

Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

Korenko, Michael K. (Wexford, PA)

1985-01-01

53

Precipitation hardening austenitic superalloys  

Microsoft Academic Search

Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation

Korenko; Michael K

1985-01-01

54

RHOBOT: Radiation hardened robotics  

SciTech Connect

A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States)

1997-10-01

55

Nuclear effects hardened shelters  

NASA Astrophysics Data System (ADS)

The Houston Fearless 76 Government Projects Group has been actively engaged for more than twenty-five years as a sub-contractor and currently as a prime contractor in the design, manufacture, repair and logistics support of custom mobile ground stations and their equipment accommodations. Other associated products include environmental control units (ECU's), mobilizers for shelters and a variety of mobile power generation units (MPU's). Since 1984, Houston Fearless 76 has designed and manufactured four 8' x 8' x 22' nuclear hardened mobile shelters. These shelters were designed to contain electronic data processing/reduction equipment. One shelter is currently being operated by the Air Force as a Defense Intelligence Agency (DIA) approved and certified Special Corrpartmented Information Facility (SCIF). During the development and manufacturing process of the shelters, we received continual technical assistance and design concept evaluations from Science Applications International Corporation (SAIC) Operations Analysis and Logistics Engineering Division and the Nondestructive Inspection Lab at McClellan AFB. SAIC was originally employed by the Air Force to design the nuclear hardening specifications applied to these shelters. The specific levels of hardening to which the shelters were designed are classified and will not be mentioned during this presentation.

Lindke, Paul

1990-11-01

56

Acute exposure to cold rapidly increases the number of nucleotide binding sites, but not proton conductance, in BAT mitochondria  

Microsoft Academic Search

Studies on the effect of acute cold exposure of rats on brown adipose tissue (BAT) thermogenic activity have produced equivocal results. Therefore, the authors have reexamined the response of BAT mitochondria to abrupt changes in environmental temperature. ³H-GDP binding to BAT mitochondria increased more than 2-fold in 20 min when rats were moved from 27°C to 4°C. When rats housed

A. G. Swick; R. W. Swick

1986-01-01

57

Multipurpose hardened spacecraft insulation  

NASA Technical Reports Server (NTRS)

A Multipurpose Hardened Spacecraft Multilayer Insulation (MLI) system was developed and implemented to meet diverse survivability and performance requirements. Within the definition and confines of a MLI assembly (blanket), the design: (1) provides environmental protection from natural and induced nuclear, thermal, and electromagnetic radiation; (2) provides adequate electrostatic discharge protection for a geosynchronous satellite; (3) provides adequate shielding to meet radiated emission needs; and (4) will survive ascent differential pressure loads between enclosed volume and space. The MLI design is described which meets these requirements and design evolution and verification is discussed. The application is for MLI blankets which closeout the area between the laser crosslink subsystem (LCS) equipment and the DSP spacecraft cabin. Ancillary needs were implemented to ease installation at launch facility and to survive ascent acoustic and vibration loads. Directional venting accommodations were also incorporated to avoid contamination of LCS telescope, spacecraft sensors, and second surface mirrors (SSMs).

Steimer, Carlos H.

1990-01-01

58

Surface Modifications of Rapid Hydrothermal Synthesized ZnO Nanowires on PET Substrate by Cold Plasma Jet Array  

Microsoft Academic Search

ZnO nanowire arrays on polyethylene terephthalate substrate were characterized, in terms of surface energy, by the honeycomb structured plasma jets for biosensors. A rapid hy- drothermal synthesis is carried out to grow ZnO nanowires by a variable power microwave sintering system. The optical emission spectra of the honeycomb structured plasma jet array show that excited OH, N2 ,N + ,

Jae Young Kim; Jang Bo Shim; Sung-O Kim

2011-01-01

59

Surface hardening of precipitation-hardening nonmagnetic steels  

Microsoft Academic Search

1.Precipitation-hardening nonmagnetic steels of the Fe-Mn-Ni system can be surface hardened by nitriding and also by work hardening of the surface. Surface layers with an elevated hardness to a depth of 0.3 mm can be obtained by nitriding of high-strength nonmagnetic steel 40G14N9Kh3YuF2. The results of comparative wear resistance tests showed that nitrided steel 40G14N9Kh3YuF2 is not inferior to steel

V. M. Blinov; R. M. Volkova; Yu. K. Kovneristyi; V. A. Rudman; Yu. V. Sorokin

1973-01-01

60

Rapid determination of total mercury in treated waste water by cold vapor atomic absorption spectrometry in alkaline medium with sodium hypochlorite solution.  

PubMed

Addition of a sodium hypochlorite solution (9.2% (w/v)) was effective to reduce a sulfide interference in determination of organic mercury, including methylmercury and phenylmercury, as well as a previously reported determination of inorganic mercury by cold vapor atomic absorption spectrometry (CVAAS) in an alkaline medium. Total mercury ranging from 0.17 to 33mugL(-1) in 15mL of sample solutions containing up to 200mgL(-1) of sulfide can be determined without any serious interference by sulfide when 1mL of the sodium hypochlorite solution was added after dilution of the sample solution to 25mL. The proposed method was simple and rapid because no digestion processes were required for the determination of total mercury; the time required for the determination was only about 5min. The proposed method was applicable to the analysis of treated waste water. PMID:18969639

Kagaya, Shigehiro; Kuroda, Yoshiharu; Serikawa, Yuka; Hasegawa, Kiyoshi

2004-10-01

61

Fire vehicle hardening  

SciTech Connect

After attack, the wartime fire fighter faces a harsh environment in which he must operate to perform his mission. Debris, unexploded bombs, and munitions pose hazards that must be overcome. Without modification to the fire-fighting vehicles, there is little assurance that the fire fighter would even be able to reach the locations necessary for performing his mission. Adding armor to the vehicle to protect both the operator and the vehicle from these hazards is the proposed solution. Through a study performed by the BDM Corporation under a subcontract to Martin Marietta Energy Systems, Inc., the recommended types, thicknesses, and locations of material necessary to allow the P-19 crash-rescue fire vehicle to survive, with 95% probability, 100 random events using the NATO Standard Fragment Threat Criteria was determined. Using this information, a preliminary design for a prototype hardening kit for the P-19 was developed. In conjunction with this effort, a P-19 was modified by installing attachment points, and mock-up armor was fabricated and fitted to the vehicle to refine the design. The kit design consisted of (1) various mild steel panels that varied in thickness from 0.125 to 0.375 in., (2) Lexan panels for areas that had to be transparent, (3) flexible Kevlar 49 for areas requiring flexibility, and (4) foam-filled tires. The factors considered in the design were the effects on the vehicle, fragment-stopping ability, weight, cost, ability to fabricate, and ease of installation. 40 figs.

Horner, L.G.

1988-11-01

62

Strain hardening at large strains  

SciTech Connect

The strain hardening properties of various fcc metals have been investigated at large strains by means of torsion tests of short thin-walled cylinders. The results show that Stage IV occurs in all cases provided that a low enough test temperature is used; it is a nearly constant hardening rate of 2.10/sup /minus/4/ G in terms of resolved flow stress. Stage IV strain hardening has been modeled by considering the effects of accumulation of dislocation debris, such as dipoles and loops, in the ''saturation'' stress. The ''saturation'' stress that can be obtained by extrapolation of Stage III is now a limiting flow stress that slowly increases with the accumulation of debris. The model reproduces the sharp transition from Stage III to Stage IV that occurs experimentally at low temperatures and, for a reasonable choice of parameters, the rate of hardening in Stage IV. 15 refs., 8 figs.

Rollett, A.D.; Kocks, U.F.; Embury, J.D.; Stout, M.G.; Doherty, R.D.

1988-01-01

63

Phase Stability of Al-5Fe-V-Si Coatings Produced by Cold Gas Dynamic Spray Process Using Rapidly Solidified Feedstock Materials  

NASA Astrophysics Data System (ADS)

In this study, aluminum alloy Al-5Fe-V-Si (in wt.%) feedstock powder, produced by rapid solidification (RS) using the gas atomization process, was selected to produce high-temperature resistant Al-alloy coatings using the cold gas dynamic spraying process (CGDS). The alloy composition was chosen for its mechanical properties at elevated temperature for potential applications in internal-combustion (IC) engines. The CGDS spray process was selected due to its relatively low operating temperature, thus preventing significant heating of the particles during spraying and as such allowing the original phases of the feedstock powder to be preserved within the coatings. The microstructure and phases stability was investigated by means of Scanning Electron Microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetery techniques. The coatings mechanical properties were evaluated through bond strength and microhardness testing. The study revealed the conservation of the complex microstructure of the rapid solidified powder during the spray process. Four distinct microstructures were observed as well as two different phases, namely a Al13(Fe,V)3Si silicide phase and a metastable (Al,Si) x (Fe,V) Micro-quasicrystalline Icosahedral (MI) phase. Aging of the coating samples was performed and confirmed that the phase transformation of the metastable phases and coarsening of the nanosized precipitates will occurs at around 400 °C. The metastable MI phase was determined to be thermally stable up to 390 °C, after which a phase transformation to silicide starts to occur.

Bérubé, G.; Yandouzi, M.; Zúñiga, A.; Ajdelsztajn, L.; Villafuerte, J.; Jodoin, B.

2012-03-01

64

The Use of a Simple Enzyme Assay in 'Seed-Hardening' Studies  

ERIC Educational Resources Information Center

Describes a single technique for an enzyme assay of catalase. The method shows that vegetable seeds submitted to pre-sowing 'hardening' cycles of imbition and drying have greater catalase activity and more rapid germination than do the controls. (LS)

Ead, J.; Devonald, V. G.

1975-01-01

65

Deformation of plastically compressible hardening-softening-hardening solids  

NASA Astrophysics Data System (ADS)

Motivated by a model of the response of vertically aligned carbon nanotube (VACNT) pillars in uniaxial compression, we consider the deformation of a class of compressible elastic-viscoplastic solids with a hardeningsoftening-hardening variation of flow strength with plastic strain. In previous work (Hutchens et al. 2011) a constitutive relation was presented and used to model the response of VACNT pillars in axisymmetric compression. Subsequently, it was found that due to a programming error the constitutive relation presented in the paper (Hutchens et al. 2011) was not the one actually implemented. In particular, the plastic flow rule actually used did not satisfy plastic normality. Here, we present the constitutive formulation actually implemented in the previous work (Hutchens et al. 2011). Dynamic, finite deformation, finite element calculations are carried out for uniaxial compression, uniaxial tension and for indentation of a "half-space" by a conical indenter tip. A sequential buckling-like deformation mode is found in compression when there is plastic non-normality and hardeningsoftening-hardening. The same material characterization gives rise to a Lüders band-like deformation mode in tension. When there is a deformation mode with a sharp front along mesh boundaries, the overall stress-strain response contains high frequency oscillations that are a mesh artifact. The responses of non-softening solids are also analyzed and their overall stress-strain behavior and deformation modes are compared with those of hardening-softening-hardening solids. We find that indentation with a sharp indenter tip gives a qualitatively equivalent response for hardening and hardening-softening-hardening solids.

Needleman, A.; Hutchens, S. B.; Mohan, N.; Greer, J. R.

2012-08-01

66

How Cold Is Cold?  

NSDL National Science Digital Library

Heat and cold are often difficult concepts for children to understand. First, our everyday sloppy language gives them a predisposition to such common misconceptions as cold being a substance that moves from place to place. Our colloquial language often re

Richard Konicek-Moran

2008-04-01

67

The cold resistance of Macaronesian Sempervivoideae  

Microsoft Academic Search

Cold resistance of twenty-seven species of Macaronesian Sempervivoideae uniformly cultivated under cool moderate but not hardening conditions was measured. The resistance limits of all the tested species ranged between-4 and-10°C. Cold stress response was principially different: Cold resistance of about half of the tested species was due to freezing point lowering. This response type, avoidance of freezing, in which any

R. Lösch; L. Kappen

1981-01-01

68

Ontogenetic variation in cold tolerance plasticity in Drosophila: is the Bogert effect bogus?  

NASA Astrophysics Data System (ADS)

Ontogenetic variation in plasticity is important to understanding mechanisms and patterns of thermal tolerance variation. The Bogert effect postulates that, to compensate for their inability to behaviourally thermoregulate, less-mobile life stages of ectotherms are expected to show greater plasticity of thermal tolerance than more-mobile life stages. We test this general prediction by comparing plasticity of thermal tolerance (rapid cold-hardening, RCH) between mobile adults and less-mobile larvae of 16 Drosophila species. We find an RCH response in adults of 13 species but only in larvae of four species. Thus, the Bogert effect is not as widespread as expected.

Mitchell, Katherine A.; Sinclair, Brent J.; Terblanche, John S.

2013-03-01

69

Methods for Designing Concurrently Strengthened Severely Deformed Age-Hardenable Aluminum Alloys by Ultrafine-Grained and Precipitation Hardenings  

NASA Astrophysics Data System (ADS)

The age-hardenings behavior and precipitate microstructures with high dislocation density and/or ultrafine grains have been studied for 6022Al-Mg-Si and 2091Al-Li-Cu alloys. The high-pressure torsion (HPT) specimen of the former alloy exhibited either suppressed age hardenings or even age softening, unlike in the cases of the undeformed and cold-rolled specimens, at room temperature (RT) to 443 K (170 °C). On the other hand, the HPT specimen of the latter alloy successfully increased the hardness up to >HV290 at 373 K (100 °C), suggesting that concurrent strengthening by ultrafine-grained and precipitation hardenings can be activated if both alloy system and aging temperature are optimally selected. The corresponding transmission electron microscopy (TEM) microstructures attributed such a high level of hardness to the transgranular precipitation of the nanometer-scale particles within ultrafine grains. From the results of in situ small-angle X-ray scattering (SAXS) measurements, methods to maximize the effect of the combined processing of severe plastic deformation (SPD) and the age-hardenings technique are proposed based on the underlying phase transformation mechanisms.

Hirosawa, Shoichi; Hamaoka, Takumi; Horita, Zenji; Lee, Seungwon; Matsuda, Kenji; Terada, Daisuke

2013-08-01

70

Precipitation hardening in aluminum alloy 6022  

SciTech Connect

Although the precipitation process in Al-Mg-Si alloys has been extensively studied, the understanding of the hardening process is still incomplete, since any change in composition, processing and aging practices, etc., could affect the precipitation hardening behavior. In this paper, hardness measurements, differential scanning calorimetry and transmission electron microscopy have been utilized to study the precipitation hardening behavior in aluminum alloy 6022.

Miao, W.F.; Laughlin, D.E. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering] [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering

1999-03-05

71

Forming an age hardenable aluminum alloy with intermediate annealing  

NASA Astrophysics Data System (ADS)

A method to improve formability of aluminum sheet alloys by a two-stage stamping process with intermediate annealing was developed for a non-age hardenable Al-Mg alloy where the annealing heat treatment provided recovery of cold work from the initial stamping and recrystallization of the microstructure to enhance the forming limits of the material. This method was extended to an age hardenable, Al-Mg-Si alloy, which is complicated by the competing metallurgical effects during heat treatment including recovery (softening effect) vs. precipitation (hardening effect). An annealing heat treatment process condition was discovered wherein the stored strain energy from an initial plastic deformation can be sufficiently recovered to enhance formability in a second deformation; however, there is a deleterious effect on subsequent precipitation hardening. The improvement in formability was quantified with uniaxial tensile tests as well as with the forming limit diagram. Since strain-based forming limit curves (FLC) are sensitive to pre-strain history, both stress-based FLCs and polar-effective-plastic-strain (PEPS) FLCs, which are path-independent, were used to evaluate the forming limits after preform annealing. A technique was developed to calculate the stress-based FLC in which a residual-effective-plastic-strain (REPS) was determined by overlapping the hardening curve of the pre-strained and annealed material with that of the simply-annealed- material. After converting the strain-based FLCs using the constant REPS method, it was found that the stress-based FLCs and the PEPS FLCs of the post-annealed materials were quite similar and both tools are applicable for evaluating the forming limits of Al-Mg-Si alloys for a two-step stamping process with intermediate annealing.

Wang, Kaifeng; Carsley, John E.; Stoughton, Thomas B.; Li, Jingjing; Zhang, Lianhong; He, Baiyan

2013-12-01

72

An acute injection of corticosterone increases thyrotrophin-releasing hormone expression in the paraventricular nucleus of the hypothalamus but interferes with the rapid hypothalamus pituitary thyroid axis response to cold in male rats.  

PubMed

The activity of the hypothalamic-pituitary-thyroid (HPT) axis is rapidly adjusted by energy balance alterations. Glucocorticoids can interfere with this activity, although the timing of this interaction is unknown. In vitro studies indicate that, albeit incubation with either glucocorticoid receptor (GR) agonists or protein kinase A (PKA) activators enhances pro-thyrotrophin-releasing hormone (pro-TRH) transcription, co-incubation with both stimuli reduces this enhancement. In the present study, we used primary cultures of hypothalamic cells to test whether the order of these stimuli alters the cross-talk. We observed that a simultaneous or 1-h prior (but not later) activation of GR is necessary to inhibit the stimulatory effect of PKA activation on pro-TRH expression. We tested these in vitro results in the context of a physiological stimulus on the HPT axis in adult male rats. Cold exposure for 1 h enhanced pro-TRH mRNA expression in neurones of the hypophysiotrophic and rostral subdivisions of the paraventricular nucleus (PVN) of the hypothalamus, thyrotrophin (TSH) serum levels and deiodinase 2 (D2) activity in brown adipose tissue (BAT). An i.p. injection of corticosterone stimulated pro-TRH expression in the PVN of rats kept at ambient temperature, more pronouncedly in hypophysiotrophic neurones that no longer responded to cold exposure. In corticosterone-pretreated rats, the cold-induced increase in pro-TRH expression was detected only in the rostral PVN. Corticosterone blunted the increase in serum TSH levels and D2 activity in BAT produced by cold in vehicle-injected animals. Thus, increased serum corticosterone levels rapidly restrain cold stress-induced activation of TRH hypophysiotrophic neurones, which may contribute to changing energy expenditure. Interestingly, TRH neurones of the rostral PVN responded to both corticosterone and cold exposure with an amplified expression of pro-TRH mRNA, suggesting that these neurones integrate stress and temperature distinctly from the hypophysiotrophic neurones. PMID:25283355

Sotelo-Rivera, I; Jaimes-Hoy, L; Cote-Vélez, A; Espinoza-Ayala, C; Charli, J-L; Joseph-Bravo, P

2014-12-01

73

Method for determining the hardness of strain hardening articles of tungsten-nickel-iron alloy  

DOEpatents

The present invention is directed to a rapid nondestructive method for determining the extent of strain hardening in an article of tungsten-nickel-iron alloy. The method comprises saturating the article with a magnetic field from a permanent magnet, measuring the magnetic flux emanating from the article, comparing the measurements of the magnetic flux emanating from the article with measured magnetic fluxes from similarly shaped standards of the alloy with known amounts of strain hardening to determine the hardness.

Wallace, Steven A. (Knoxville, TN)

1984-01-01

74

Cold Hardening of Meloidogyne hapla Second-stage Juveniles  

PubMed Central

The effect of previous exposure to low temperatures on freezing tolerance was determined for second-stage juveniles of Meloidogyne hapla. Juveniles in 5% polyethylene glycol 20,000 were exposed to 0-24 C for 12-96 hours, and then freezing tolerance was assessed by freezing samples at -4 C for 24 hours, thawing, and determining survival. Freezing tolerance was inversely related to prefreeze temperatures of 4-24 C. Prefreeze exposure to 4 C resulted in fourfold greater freezing tolerance than did exposure to 24 C. Mortality occurred during prefreeze exposure to 0 C. Most of the increase in freezing tolerance at 4 C occurred during the first 12 hours. In soil, prefreeze exposure to 4 C resulted in greater freezing tolerance than did prefreeze exposure to 24 C. PMID:19287695

Forge, T. A.; MacGuidwin, A. E.

1990-01-01

75

Low-temperature tolerance and cold hardening of cacti  

Microsoft Academic Search

Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over

Nobel

1982-01-01

76

Low temperature tolerance and cold hardening of cacti  

Microsoft Academic Search

Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over

Nobel

1982-01-01

77

Cold forming of aluminium—state of the art  

Microsoft Academic Search

The ongoing development of cold forging technology has been manifested lately by the increasing application of components in cold forged aluminium alloys. Applying precipitation hardening alloys components with great strength\\/weight ratio can be produced with a strength comparable to that of unalloyed steel. After description of the different types of alloys and their individual properties and applications, the special requirements

N. Bay

1997-01-01

78

Common Cold  

MedlinePLUS

... nose, coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In ... avoid colds. There is no cure for the common cold. For relief, try Getting plenty of rest Drinking ...

79

Rapid Low Temperature-Induced Stomatal Closure Occurs in Cold-Tolerant Commelina communis Leaves But Not in Cold-Sensitive Tobacco Leaves, via a Mechanism That Involves Apoplastic Calcium But Not Abscisic Acid1  

PubMed Central

Commelina communis stomata closed within 1 h of transferring intact plants from 27°C to 7°C, whereas tobacco (Nicotiana rustica) stomata did not until the leaves wilted. Abscisic acid (ABA) did not mediate cold-induced C. communis stomatal closure: At low temperatures, bulk leaf ABA did not increase; ABA did not preferentially accumulate in the epidermis; its flux into detached leaves was lower; its release from isolated epidermis was not greater; and stomata in epidermal strips were less sensitive to exogenous ABA. Stomata of both species in epidermal strips on large volumes of cold KCl failed to close unless calcium was supplied. Therefore, the following cannot be triggers for cold-induced stomatal closure in C. communis: direct effects of temperature on guard or epidermal cells, long-distance signals, and effects of temperature on photosynthesis. Low temperature increased stomatal sensitivity to external CaCl2 by 50% in C. communis but only by 20% in tobacco. C. communis stomata were 300- to 1,000-fold more sensitive to calcium at low temperature than tobacco stomata, but tobacco epidermis only released 13.6-fold more calcium into bathing solutions than C. communis. Stomata in C. communis epidermis incubated on ever-decreasing volumes of cold calcium-free KCl closed on the lowest volume (0.2 cm3) because the epidermal apoplast contained enough calcium to mediate closure if this was not over diluted. We propose that the basis of cold-induced stomatal closure exhibited by intact C. communis leaves is increased apoplastic calcium uptake by guard cells. Such responses do not occur in chill-sensitive tobacco leaves. PMID:11500555

Wilkinson, Sally; Clephan, Alison Lee; Davies, William John

2001-01-01

80

COSMIC-RAY HELIUM HARDENING  

SciTech Connect

Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 10{sup 15}eV, and (2) all CR spectra become hard at {approx}>10{sup 11}eV nucleon{sup -1}. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at {approx}100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with {approx}10{sup 6} K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito, E-mail: ohira@post.kek.jp [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan)

2011-03-01

81

Insect Cold-Hardiness: To Freeze or Not to Freeze Richard E. Lee, Jr.  

E-print Network

. The capacity to cold-harden is required for overwintering to survive long-term or short-term exposure to lowInsect Cold-Hardiness: To Freeze or Not to Freeze Richard E. Lee, Jr. BioScience, Vol. 39, No. 5 #12;Insect Cold-hardiness: To Freeze or Not to Freeze How insects survive low temperatures

Lee Jr., Richard E.

82

Plasma hardening of ridges of railway wheelsets  

Microsoft Academic Search

Plasma surface strengthening plant and processing of the rail rolling stock wheel pairs are described here. Following on from starting the equipment design up to hardened wheel pairs' acceptance, accurate adherence of the process-dependent parameters at plasma treatment, and automated control ensure hardened surface structure and properties stability, as the final result it guarantees road safety.

S. V. Antipovskii; A. S. Tyuftyaev

2011-01-01

83

``Work-Hardenable'' Ductile Bulk Metallic Glass  

Microsoft Academic Search

Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<1%) at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive ``work hardening'' and large ductility of 18%. Significant increase in the flow stress was observed during deformation. The ``work-hardening'' capability and ductility

Jayanta Das; Mei Bo Tang; Ki Buem Kim; Ralf Theissmann; Falko Baier; Wei Hua Wang; Jürgen Eckert

2005-01-01

84

Cyber situational awareness and differential hardening  

NASA Astrophysics Data System (ADS)

The advent of cyber threats has created a need for a new network planning, design, architecture, operations, control, situational awareness, management, and maintenance paradigms. Primary considerations include the ability to assess cyber attack resiliency of the network, and rapidly detect, isolate, and operate during deliberate simultaneous attacks against the network nodes and links. Legacy network planning relied on automatic protection of a network in the event of a single fault or a very few simultaneous faults in mesh networks, but in the future it must be augmented to include improved network resiliency and vulnerability awareness to cyber attacks. Ability to design a resilient network requires the development of methods to define, and quantify the network resiliency to attacks, and to be able to develop new optimization strategies for maintaining operations in the midst of these newly emerging cyber threats. Ways to quantify resiliency, and its use in visualizing cyber vulnerability awareness and in identifying node or link criticality, are presented in the current work, as well as a methodology of differential network hardening based on the criticality profile of cyber network components.

Dwivedi, Anurag; Tebben, Dan

2012-06-01

85

Application of plastic anisotropy and non-isotropic hardening to springback prediction  

NASA Astrophysics Data System (ADS)

Springback is sensitive to the stress/moment distribution following a forming operation. To assess the sensitivity of springback to plastic hardening laws, special draw/bend tests were analyzed and compared to existing measurements. Systematic discrepancies were noted. Uniaxial tension-compression results were utilized to construct reverse hardening rules for three sheet materials: drawing-quality silicon-killed steel (DQSK), high-strength low-alloy steel (HSLA), and 6022-T4 aluminum alloy (6022-T4). A two-surface plasticity model was constructed, consisting of an active yield surface and a bounding surface. Initial yield was of the von Mises type. The active surface is of the Armstrong-Frederick type, with extra terms added to allow for the translation of the active yield to be influenced by the translation of the bounding surface (or limiting surface). To model the permanent softening observed in the tension-compression tests, the bounding surface was allowed to translate and expand according to a mixed hardening rule. This model effectively reproduces the two main features of the measured reverse hardening behavior of metal sheets: (1) low yield stress and rapid initial work hardening, and (2) persistent offset of long-strain hardening relative to isotropic hardening. Application of the new hardening model to simulations of springback with the draw/bend test improves the quality of agreement by a factor of two, compared to the results from the conventional isotropic hardening model. The hardening model is further extended to incorporate several forms of initial plastic anisotropy: Hill's quadric yield function, Barlat's three-parameter yield function, and Barlat's 1996 yield function. In addition to modeling the transient hardening and permanent softening of the uniaxial reverse loading curve, the new laws thus also take into account variations of R-value and yield stress with direction. These constitutive equations were implemented in ABAQUS via the UMAT option. Depending on the choice of yield function, the springback prediction of the draw/bend test for aluminum alloys is shown to improve, especially at lower back forces. The planar anisotropy has a strong influence on the loaded and unloaded anticlastic curvatures generated from the bending and unbending deformation in the draw/bend test. The combination of Barlat's 1996 yield function and the hardening model incorporating the Bauschinger effect give improved predictions of springback angles and anticlastic curvature.

Geng, Lumin

2000-10-01

86

Low Temperature Salt Bath Hardening of AISI 201 Austenitic Stainless Steel  

NASA Astrophysics Data System (ADS)

Salt bath hardening at low temperature was applied in order to enhance the surface hardness of AISI 201 stainless steel. The structure and properties of the hardened layer were investigated, such as microstructure, hardness, wear resistance and corrosion resistance. The experiment results show that the treatment temperature plays an importance role in the microstructure and properties of the hardened layer. If the treatment temperature is below 460°C, the hardened layer was a face centre tetragonal (fct) structure without chromium nitride precipitation. The corrosion resistance of hardened layer is better than the matrix and as good as AISI 316 austenitic stainless steel. If the temperature rises above 460 °C the precipitation show up and the corrosion resistance gets worse. The hardness and thickness of the layer increase as the raising of treatment temperature. The test of wear resistance shows that the amount of wear reduces rapidly after hardening treatment and the worn morphology of the surface behaves abrasive wear while that of AISI 201 stainless steel behaves adhesive wear.

Luo, H. S.; Zhao, C.

87

A multidisciplinary approach to the identification and evaluation of novel concepts for deeply buried hardened target defeat  

Microsoft Academic Search

During the Cold War, Deeply Buried Hardened Targets (DBHTs) and the assets they protected were of great strategic and tactical concern to the Department of Defense. Megaton-class nuclear warheads were the only viable means of attacking many of these facilities, and even so, a small subset of DBHTs was anticipated to be robust even in the face of such an

Ewell Caleb Branscome

2006-01-01

88

Common Cold  

NSDL National Science Digital Library

This Web site provides comprehensive information, selected by medical doctors, about the common cold. "The goal is to provide a framework for critical thinking which will allow informed decisions about medical care for the common cold." The section entitled Understanding Colds gives a detailed overview of how the cold virus invades the human body and how cold symptoms are caused. Information about preventing colds, and some of the complications that can occur are also included. The Special Features section includes one of the most interesting parts of the site -- Myths of the Common Cold. This site should be interesting to almost anyone, but perhaps more so for those of us who have recently had a cold.

89

Laser Surface Hardening of Groove Edges  

NASA Astrophysics Data System (ADS)

Surface hardening of groove-edges made of 3Cr13 Stainless Steel has been carried out using 500 W CO2 laser with a rectangular beam of 2.5×3 mm2. The processing speed was varied from 150-500 mm/min. It was seen that the hardened depth increases with increase in laser interaction time. A maximum hardened depth of around 1mm was achieved. The microhardness of the transformed zone was 2.5 times the hardness of base metal. The XRD's and microstructural analysis were also reported.

Hussain, A.; Hamdani, A. H.; Akhter, R.; Aslam, M.

2013-06-01

90

Common cold  

MedlinePLUS

The common cold usually causes a runny nose, nasal congestion, and sneezing. You may also have a sore throat, cough, ... It is called the “common cold” for good reason. There are over one billion colds in the United States each year. You and your children will ...

91

A novel plant defensin-like gene of winter wheat is specifically induced during cold acclimation.  

PubMed

A novel cDNA clone, Tad1, was isolated from crown tissue of winter wheat after differential screening of cold acclimation-induced genes. The Tad1 cDNA encoded a 23kDa polypeptide with a potential N-terminal signal sequence. The putative mature sequence showed striking similarity to plant defensins or gamma-thionins, representing low molecular size antipathogenic polypeptides. High levels of Tad1 mRNA accumulation occurred within one day of cold acclimation in crown tissue and the level was maintained throughout 14 days of cold acclimation. Similar rapid induction was observed in young seedlings treated with low temperature but not with exogenous abscisic acid. In contrast to defensins from other plant species, neither salicylic acid nor methyl jasmonate induced expression of Tad1. The recombinant mature form of TAD1 polypeptide inhibited the growth of the phytopathogenic bacteria, Pseudomonas cichorii; however, no antifreeze activity was detected. Collectively, these data suggested that Tad1 is induced in cold-acclimated winter wheat independent of major defense signaling(s) and is involved in low temperature-induced resistance to pathogens during winter hardening. PMID:12379218

Koike, Michiya; Okamoto, Takashi; Tsuda, Sakae; Imai, Ryozo

2002-10-18

92

Process for hardening the surface of polymers  

DOEpatents

Hard surfaced polymers and the method for making them is generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface and improved wear resistance. 1 figure.

Mansur, L.K.; Lee, E.H.

1992-07-14

93

Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d+Au collisions at sqrt(s_NN)=200 GeV  

E-print Network

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay muons over the transverse momentum range 1 < pT < 6 GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p+p collisions at ?sNN = 200 GeV. In central d+Au collisions an enhancement (suppression) of heavy-flavor muon production is observed at backward (forward) rapidity relative to the yield in p+p collisions scaled by the number of binary collisions. Modification of the gluon density distribution in the Au nucleus contributes in terms of anti-shadowing enhancement and shadowing suppression; however, the enhancement seen at backward rapidity exceeds expectations from this effect alone. These results, implying an important role for additional cold nuclear matter effects, serves as a key baseline for heavy-quark measurements in A+A collisions and in constraining the magnitude of charmonia breakup effects at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

A. Adare; C. Aidala; N. N. Ajitanand; Y. Akiba; R. Akimoto; H. Al-Bataineh; H. Al-Ta'ani; J. Alexander; K. R. Andrews; A. Angerami; K. Aoki; N. Apadula; E. Appelt; Y. Aramaki; R. Armendariz; E. C. Aschenauer; E. T. Atomssa; R. Averbeck; T. C. Awes; B. Azmoun; V. Babintsev; M. Bai; G. Baksay; L. Baksay; B. Bannier; K. N. Barish; B. Bassalleck; A. T. Basye; S. Bathe; V. Baublis; C. Baumann; A. Bazilevsky; S. Belikov; R. Belmont; J. Ben-Benjamin; R. Bennett; J. H. Bhom; D. S. Blau; J. S. Bok; K. Boyle; M. L. Brooks; D. Broxmeyer; H. Buesching; V. Bumazhnov; G. Bunce; S. Butsyk; S. Campbell; A. Caringi; P. Castera; C. -H. Chen; C. Y. Chi; M. Chiu; I. J. Choi; J. B. Choi; R. K. Choudhury; P. Christiansen; T. Chujo; P. Chung; O. Chvala; V. Cianciolo; Z. Citron; B. A. Cole; Z. Conesa del Valle; M. Connors; M. Csanád; T. Csörg?; T. Dahms; S. Dairaku; I. Danchev; K. Das; A. Datta; G. David; M. K. Dayananda; A. Denisov; A. Deshpande; E. J. Desmond; K. V. Dharmawardane; O. Dietzsch; A. Dion; M. Donadelli; O. Drapier; A. Drees; K. A. Drees; J. M. Durham; A. Durum; D. Dutta; L. D'Orazio; S. Edwards; Y. V. Efremenko; F. Ellinghaus; T. Engelmore; A. Enokizono; H. En'yo; S. Esumi; B. Fadem; D. E. Fields; M. Finger; M. Finger; \\, Jr.; F. Fleuret; S. L. Fokin; Z. Fraenkel; J. E. Frantz; A. Franz; A. D. Frawley; K. Fujiwara; Y. Fukao; T. Fusayasu; C. Gal; I. Garishvili; A. Glenn; H. Gong; X. Gong; M. Gonin; Y. Goto; R. Granier de Cassagnac; N. Grau; S. V. Greene; G. Grim; M. Grosse Perdekamp; T. Gunji; L. Guo; H. -Å. Gustafsson; J. S. Haggerty; K. I. Hahn; H. Hamagaki; J. Hamblen; R. Han; J. Hanks; C. Harper; K. Hashimoto; E. Haslum; R. Hayano; X. He; M. Heffner; T. K. Hemmick; T. Hester; J. C. Hill; M. Hohlmann; R. S. Hollis; W. Holzmann; K. Homma; B. Hong; T. Horaguchi; Y. Hori; D. Hornback; S. Huang; T. Ichihara; R. Ichimiya; H. Iinuma; Y. Ikeda; K. Imai; M. Inaba; A. Iordanova; D. Isenhower; M. Ishihara; M. Issah; D. Ivanischev; Y. Iwanaga; B. V. Jacak; J. Jia; X. Jiang; J. Jin; D. John; B. M. Johnson; T. Jones; K. S. Joo; D. Jouan; D. S. Jumper; F. Kajihara; J. Kamin; S. Kaneti; B. H. Kang; J. H. Kang; J. S. Kang; J. Kapustinsky; K. Karatsu; M. Kasai; D. Kawall; M. Kawashima; A. V. Kazantsev; T. Kempel; A. Khanzadeev; K. M. Kijima; J. Kikuchi; A. Kim; B. I. Kim; D. J. Kim; E. -J. Kim; Y. -J. Kim; Y. K. Kim; E. Kinney; Á. Kiss; E. Kistenev; D. Kleinjan; P. Kline; L. Kochenda; B. Komkov; M. Konno; J. Koster; D. Kotov; A. Král; A. Kravitz; G. J. Kunde; K. Kurita; M. Kurosawa; Y. Kwon; G. S. Kyle; R. Lacey; Y. S. Lai; J. G. Lajoie; A. Lebedev; D. M. Lee; J. Lee; K. B. Lee; K. S. Lee; S. H. Lee; S. R. Lee; M. J. Leitch; M. A. L. Leite; X. Li; P. Lichtenwalner; P. Liebing; S. H. Lim; L. A. Linden Levy; T. Liška; H. Liu; M. X. Liu; B. Love; D. Lynch; C. F. Maguire; Y. I. Makdisi; M. D. Malik; A. Manion; V. I. Manko; E. Mannel; Y. Mao; H. Masui; F. Matathias; M. McCumber; P. L. McGaughey; D. McGlinchey; C. McKinney; N. Means; M. Mendoza; B. Meredith; Y. Miake; T. Mibe; A. C. Mignerey; K. Miki; A. Milov; J. T. Mitchell; Y. Miyachi; A. K. Mohanty; H. J. Moon; Y. Morino; A. Morreale; D. P. Morrison; S. Motschwiller; T. V. Moukhanova; T. Murakami; J. Murata; S. Nagamiya; J. L. Nagle; M. Naglis; M. I. Nagy; I. Nakagawa; Y. Nakamiya; K. R. Nakamura; T. Nakamura; K. Nakano; S. Nam; J. Newby; M. Nguyen; M. Nihashi; R. Nouicer; A. S. Nyanin; C. Oakley; E. O'Brien; S. X. Oda; C. A. Ogilvie; M. Oka; K. Okada; Y. Onuki; A. Oskarsson; M. Ouchida; K. Ozawa; R. Pak; V. Pantuev; V. Papavassiliou; B. H. Park; I. H. Park; S. K. Park; W. J. Park; S. F. Pate; L. Patel; H. Pei; J. -C. Peng; H. Pereira; D. Yu. Peressounko; R. Petti; C. Pinkenburg; R. P. Pisani; M. Proissl; M. L. Purschke; H. Qu; J. Rak; I. Ravinovich; K. F. Read; S. Rembeczki; K. Reygers; V. Riabov; Y. Riabov; E. Richardson; D. Roach; G. Roche; S. D. Rolnick; M. Rosati; C. A. Rosen; S. S. E. Rosendahl; P. Ruži?ka; B. Sahlmueller; N. Saito; T. Sakaguchi; K. Sakashita; V. Samsonov; S. Sano; M. Sarsour; T. Sato; M. Savastio; S. Sawada; K. Sedgwick; J. Seele; R. Seidl; R. Seto; D. Sharma; I. Shein; T. -A. Shibata; K. Shigaki; H. H. Shim; M. Shimomura; K. Shoji; P. Shukla; A. Sickles; C. L. Silva; D. Silvermyr; C. Silvestre; K. S. Sim; B. K. Singh; C. P. Singh; V. Singh; M. Slune?ka; T. Sodre; R. A. Soltz; W. E. Sondheim; S. P. Sorensen; I. V. Sourikova; P. W. Stankus; E. Stenlund; S. P. Stoll; T. Sugitate; A. Sukhanov; J. Sun; J. Sziklai; E. M. Takagui; A. Takahara; A. Taketani; R. Tanabe; Y. Tanaka; S. Taneja; K. Tanida; M. J. Tannenbaum; S. Tarafdar; A. Taranenko; E. Tennant; H. Themann; D. Thomas; T. L. Thomas; M. Togawa; A. Toia; L. Tomášek; M. Tomášek; H. Torii; R. S. Towell; I. Tserruya; Y. Tsuchimoto; K. Utsunomiya; C. Vale; H. Valle; H. W. van Hecke; E. Vazquez-Zambrano; A. Veicht; J. Velkovska; R. Vértesi; M. Virius; A. Vossen; V. Vrba; E. Vznuzdaev

2013-10-03

94

Long-Term Cold Acclimation Extends Survival Time at 0°C and Modifies the Metabolomic Profiles of the Larvae of the Fruit Fly Drosophila melanogaster  

PubMed Central

Background Drosophila melanogaster is a chill-susceptible insect. Previous studies on this fly focused on acute direct chilling injury during cold shock and showed that lower lethal temperature (LLT, approximately ?5°C) exhibits relatively low plasticity and that acclimations, both rapid cold hardening (RCH) and long-term cold acclimation, shift the LLT by only a few degrees at the maximum. Principal Findings We found that long-term cold acclimation considerably improved cold tolerance in fully grown third-instar larvae of D. melanogaster. A comparison of the larvae acclimated at constant 25°C with those acclimated at constant 15°C followed by constant 6°C for 2 d (15°C?6°C) showed that long-term cold acclimation extended the lethal time for 50% of the population (Lt50) during exposure to constant 0°C as much as 630-fold (from 0.137 h to 86.658 h). Such marked physiological plasticity in Lt50 (in contrast to LLT) suggested that chronic indirect chilling injury at 0°C differs from that caused by cold shock. Long-term cold acclimation modified the metabolomic profiles of the larvae. Accumulations of proline (up to 17.7 mM) and trehalose (up to 36.5 mM) were the two most prominent responses. In addition, restructuring of the glycerophospholipid composition of biological membranes was observed. The relative proportion of glycerophosphoethanolamines (especially those with linoleic acid at the sn-2 position) increased at the expense of glycerophosphocholines. Conclusion Third-instar larvae of D. melanogaster improved their cold tolerance in response to long-term cold acclimation and showed metabolic potential for the accumulation of proline and trehalose and for membrane restructuring. PMID:21957472

Koštál, Vladimír; Korbelová, Jaroslava; Rozsypal, Jan; Zahradní?ková, Helena; Cimlová, Jana; Tom?ala, Aleš; Šimek, Petr

2011-01-01

95

Plant development affects the cold-induced expression of plant defence-related transcripts in winter wheat  

Microsoft Academic Search

In winter cereals, low temperature hardening, plant age and genotype are known to influence the expression of resistance to snow mould diseases. A study was undertaken to determine the effects of genotype, plant age and duration of cold hardening on the temporal expression of the PR-protein and other defence-related protein transcripts under controlled environment conditions, and in the field during

D. A Gaudet; A Laroche; M Frick; R Huel; B Puchalski

2003-01-01

96

Hard turning: AISI 4340 high strength low alloy steel and AISI D2 cold work tool steel  

Microsoft Academic Search

The aim of this paper is to evaluate the machinability of hardened steels at different levels of hardness and using a range of cutting tool materials. More specifically, the work was focused on the machinability of hardened AISI 4340 high strength low alloy steel and AISI D2 cold work tool steel. The tests involving the AISI 4340 steel were performed

J. G. Lima; R. F. Ávila; A. M. Abrão; M. Faustino; J. Paulo Davim

2005-01-01

97

Analysis of Tensile Stress-Strain and Work-Hardening Behavior in 9Cr-1Mo Ferritic Steel  

NASA Astrophysics Data System (ADS)

Detailed analysis on tensile true stress ( ?)-true plastic strain ( ?) and work-hardening behavior of 9Cr-1Mo steel have been performed in the framework of the Voce relationship and Kocks-Mecking approach for wide range of temperatures, 300 K to 873 K (27 °C to 600 °C) and strain rates (6.33 × 10-5 to 6.33 × 10-3 s-1). At all test conditions, ?- ? data were adequately described by the Voce equation. 9Cr-1Mo steel exhibited two-stage work-hardening behavior characterized by a rapid decrease in instantaneous work-hardening rate ( ? = d?/ d?) with stress at low stresses (transient stage) followed by a gradual decrease in ? at high stresses (stage III). The variations of work-hardening parameters and ?- ? as a function of temperature and strain rate exhibited three distinct temperature regimes. Both work-hardening parameters and ?- ? displayed signatures of dynamic strain aging at intermediate temperatures and dominance of dynamic recovery at high temperatures. Excellent correlations have been obtained between work-hardening parameters evaluated using the Voce relationship and the respective tensile properties. A comparison of work-hardening parameters obtained using the Voce equation and Kocks-Mecking approach suggested an analogy between the two for the steel.

Choudhary, B. K.; Palaparti, D. P. Rao; Samuel, E. Isaac

2013-01-01

98

Centrality, rapidity, and transverse-momentum dependence of cold nuclear matter effects on J/? production in dAu, CuCu, and AuAu collisions at sNN=200 GeV  

NASA Astrophysics Data System (ADS)

We have carried out a wide study of cold nuclear matter (CNM) effects on J/? production in dAu, CuCu and AuAu collisions at sNN=200 GeV. We have studied the effects of three different gluon-shadowing parametrizations, using the usual simplified kinematics for which the momentum of the gluon recoiling against the J/? is neglected as well as an exact kinematics for a 2?2 process; namely g+g?J/?+g as expected from LO pQCD. We have shown that the rapidity distribution of the nuclear modification factor RdAu, and particularly its antishadowing peak, is systematically shifted toward larger rapidities in the 2?2 kinematics, irrespective of which shadowing parametrization is used. In turn, we have noted differences in the effective final-state nuclear absorption needed to fit the PHENIX dAu data. Taking advantage of our implementation of 2?2 kinematics, we have also computed the transverse momentum dependence of the nuclear modification factor, which cannot be predicted with the usual simplified kinematics. All the corresponding observables have been computed for CuCu and AuAu collisions and compared to the PHENIX and STAR data. Finally, we have extracted the effective nuclear absorption from the recent measurements of RCP in dAu collisions by the PHENIX collaboration.

Ferreiro, E. G.; Fleuret, F.; Lansberg, J. P.; Rakotozafindrabe, A.

2010-06-01

99

Precipitation hardening in gold-cobalt alloys.  

PubMed

The precipitation hardening in gold-cobalt alloys containing less than 5 wt.%Co was studied by means of resistivity, hardness, X-ray diffraction, and optical microscopic examination. The hardness curves showed two hardness peaks after isothermal ageing below the temperature of 250 or 300 degrees C. It was considered that the first peak was due to the formation of G.P. zone which was confirmed by reversion phenomenon. The second peak was due to the growth of metastable cobalt-rich precipitate, and this stage was found to make a major contribution to the age-hardening in the present alloys. The nodular products at grain boundary do not play an important role in age-hardening. Acitvation energies, order of the reaction involved, and the rate constant for the growth process were established. The difference in growth mechanism of the metastable precipitate was deduced from the kinetics data. PMID:1065510

Miyajima, Y; Yasuda, K; Kanzawa, Y

1976-03-01

100

Modeling of Irradiation Hardening of Polycrystalline Materials  

SciTech Connect

High energy particle irradiation of structural polycrystalline materials usually produces irradiation hardening and embrittlement. The development of predict capability for the influence of irradiation on mechanical behavior is very important in materials design for next generation reactors. In this work a multiscale approach was implemented to predict irradiation hardening of body centered cubic (bcc) alpha-iron. The effect of defect density, texture and grain boundary was investigated. In the microscale, dislocation dynamics models were used to predict the critical resolved shear stress from the evolution of local dislocation and defects. In the macroscale, a viscoplastic self-consistent model was applied to predict the irradiation hardening in samples with changes in texture and grain boundary. This multiscale modeling can guide performance evaluation of structural materials used in next generation nuclear reactors.

Li, Dongsheng; Zbib, Hussein M.; Garmestani, Hamid; Sun, Xin; Khaleel, Mohammad A.

2011-09-14

101

Radiation Hardened Electronics for Space Environments (RHESE)  

NASA Technical Reports Server (NTRS)

Radiation Environmental Modeling is crucial to proper predictive modeling and electronic response to the radiation environment. When compared to on-orbit data, CREME96 has been shown to be inaccurate in predicting the radiation environment. The NEDD bases much of its radiation environment data on CREME96 output. Close coordination and partnership with DoD radiation-hardened efforts will result in leveraged - not duplicated or independently developed - technology capabilities of: a) Radiation-hardened, reconfigurable FPGA-based electronics; and b) High Performance Processors (NOT duplication or independent development).

Keys, Andrew S.; Adams, James H.; Frazier, Donald O.; Patrick, Marshall C.; Watson, Michael D.; Johnson, Michael A.; Cressler, John D.; Kolawa, Elizabeth A.

2007-01-01

102

Rapid Induction of COOLing in Stroke Patients (iCOOL1): a randomised pilot study comparing cold infusions with nasopharyngeal cooling.  

PubMed

IntroductionInduction methods for therapeutic cooling are under investigated. We compared the effectiveness and safety of cold infusions (CI) and nasopharyngeal cooling (NPC) used for cooling induction in stroke patients.MethodsA prospective, open-label, randomised (1:1), single-centre pilot trial with partially blinded safety endpoint assessment was conducted at the neurointensive care unit of Heidelberg University. Intubated stroke patients with an indication for therapeutic cooling and an intracranial pressure (ICP)/temperature brain probe were randomly assigned to CI (4°C, 2L at 4L/h) or NPC (60L/min for 1 h). Previous data suggested a maximum decrease of tympanic temperature for CI (2.1L within 35 min) after 52 min. Therefore the study period was 1-hour (15 min subperiods I-IV). The brain temperature course was the primary endpoint. Secondary measures included continuous monitoring of neurovital parameters and extracerebral temperatures. Statistical analysis based on repeated-measures analysis of variance.ResultsOf 221 patients screened, 20 were randomized within 5 months. Infusion time of 2L CI was 33¿±¿4 min in 10 patients and 10 patients received NPC for 60 min. During the first 30 min of active treatment with CI, brain temperature decreased faster than during NPC (I: ¿0.31¿±¿0.2 versus ¿0.12¿±¿0.1°C, P =0.008; II: ¿1.0¿±¿0.3 versus ¿0.49¿±¿0.3°C, P =0.001). In the CI-group, after the infusion was finished, the intervention no longer decreased brain temperature, which increased after 3.5¿±¿3.3 min. Oesophageal temperature correlated best with brain temperature during CI and NPC. Tympanic temperature reacted similarly to relative changes of brain temperature during CI, but absolute values slightly differed. CI provoked three severe adverse events during subperiods II-IV (two systolic arterial pressure (SAP), one shivering) compared with four in the NPC-group, all during subperiod I (three SAP, one ICP). Classified as possible intervention-related, two cases of ventilator failure occurred during NPC.ConclusionsIn intubated stroke patients, brain cooling is faster during CI than during NPC. Importantly, contrary to previous expectations, brain cooling stopped soon after CI cessation. Oesophageal but neither bladder nor rectal temperature is suited as surrogate for brain temperature during CI and NPC. Several severe adverse events in CI and in NPC demand further studying of safety.Trial registrationClinicalTrials.gov NCT01573117. Registered 31 March 2012. PMID:25346332

Poli, Sven; Purrucker, Jan; Priglinger, Miriam; Ebner, Matthias; Sykora, Marek; Diedler, Jennifer; Bulut, Cem; Popp, Erik; Rupp, André; Hametner, Christian

2014-10-27

103

27. LAEMPE AUTOMATED COLD BOX CORE MAKING MACHINES IN THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

27. LAEMPE AUTOMATED COLD BOX CORE MAKING MACHINES IN THE GREY IRON FOUNDRY USED PRESSURE TO SET RESINS IN CORE SAND. THE ONLY EFFORT REQUIRED OF WORKERS IS TO CHANGE CORE BOXES AND REMOVE HARDENED CORE. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

104

Introduction 5 Mechanism of Irradiation Hardening 5  

E-print Network

Figures 25 #12;- 5 - 1. INTRODUCTION It is well known that bombardment of metals by energetic neutrons induces considerable changes in their physical and mechanical properties. The increase in critical shear-produced defects with dislocations. Several irradiation hardening studies have been performed on fee metals

105

Selective Hardening Methodology for Combinational Logic  

E-print Network

Selective Hardening Methodology for Combinational Logic Samuel N. Pagliarini, Lirida A. de B of combinational logic cells. The methodology is based on the SPRA algorithm for calculating logical masking--Reliability, Single Event Effects, Selective Hard- ening, Logic Masking. I. INTRODUCTION The amount of defects as well

Paris-Sud XI, Université de

106

Ghabezloo et al.: Poromechanical behaviour of hardened cement paste under isotropic loading Poromechanical behaviour of hardened cement paste  

E-print Network

Ghabezloo et al.: Poromechanical behaviour of hardened cement paste under isotropic loading 1 Poromechanical behaviour of hardened cement paste under isotropic loading Siavash Ghabezloo1,* , Jean Sulem1 behaviour of hardened cement paste under isotropic loading is studied on the basis of an experimental

Boyer, Edmond

107

Strain hardening in underaged INCONEL 718  

Microsoft Academic Search

INCONEL 718 is a commercial, precipitation-hardenable nickel iron-base superalloy, strengthened primarily by precipitates of the metastable [gamma][double prime] phase which is based on the composition Ni[sub 3]Nb and has an ordered body-centered tetragonal (DO[sub 22]) structure. An earlier investigation on the deformation mechanisms in this alloy has shown that [gamma][double prime] precipitates are sheared by the passage of true crystallographic

M. Sundararaman; R. Kishore; P. Mukhopadhyay

1994-01-01

108

Memento: A Framework for Hardening Web Applications  

Microsoft Academic Search

We propose a generic framework called Memento for systemati cally hardening web applications. Memento models a web application's behavior using a deterministic finite automata (DFA), where each server-side script is a state, and st ate transitions are triggered by HTTP requests. We use this DFA t o defend against cross-site request forgery (CSRF) and cros s- site-scripting (XSS) attacks. The

Karthick Jayaraman; Grzegorz Lewandowski; Steve J. Chapin

2008-01-01

109

The nature of CSH in hardened cements  

Microsoft Academic Search

Calcium silicate hydrates (C-S-H) are the main binding phases in all Portland cement-based systems. This paper considers the morphology, composition, and nanostructure of C-S-H in a range of hardened cements. Inner product (Ip) C-S-H present in larger Portland cement grains typically has a fine-scale and homogeneous morphology with pores somewhat under 10 nm in diameter. Ip from larger slag grains

I. G Richardson

1999-01-01

110

A Fundamental Study of Laser Transformation Hardening  

Microsoft Academic Search

A theoretical and experimental study of heat flow and solid-state phase transformations during the laser surface hardening\\u000a of 1018 steel was conducted. In the theoretical part of the study, a three-dimensional heat flow model was developed using\\u000a the finite difference method. The surface heat loss, the temperature dependence of the surface absorptivity, and the temperature\\u000a dependence of thermal properties were

Sindo Kou; D. K. Sun; Y. P. Le

1983-01-01

111

Pulsed laser surface hardening of ferrous alloys.  

SciTech Connect

A high power pulsed Nd:YAG laser and special optics were used to produce surface hardening on 1045 steel and gray cast iron by varying the process parameters. Unlike CO{sub 2} lasers, where absorptive coatings are required, the higher absorptivity of ferrous alloys at the Nd:YAG laser wavelength eliminates the necessity of applying a coating before processing. Metallurgical analysis of the treated tracks showed that very fine and hard martensitic microstructure (1045 steel) or inhomogeneous martensite (gray cast iron) were obtained without surface melting, giving maximum hardness of HRC 61 and HRC 40 for 1045 steel and gray cast iron respectively. The corresponding maximum case depths for both alloys at the above hardness are 0.6 mm. Gray cast iron was more difficult to harden without surface melting because of its lower melting temperature and a significantly longer time-at-temperature required to diffuse carbon atoms from the graphite flakes into the austenite matrix during laser heating. The thermal distortion was characterized in term of flatness changes after surface hardening.

Xu, Z.; Reed, C. B.; Leong, K. H.; Hunter, B. V.

1999-09-30

112

Project COLD.  

ERIC Educational Resources Information Center

Describes Project COLD (Climate, Ocean, Land, Discovery) a scientific study of the Polar Regions, a collection of 35 modules used within the framework of existing subjects: oceanography, biology, geology, meterology, geography, social science. Includes a partial list of topics and one activity (geodesic dome) from a module. (Author/SK)

Kazanjian, Wendy C.

1982-01-01

113

Common Cold  

MedlinePLUS

... en español] National Library of Medicine, Medline Plus Common Cold Skip Content Marketing Share this: JavaScript is disabled in your browser. To view this content, please enable JavaScript and refresh the page. Click here for instructions on how to enable JavaScript in your browser. ...

114

Empirical beam hardening correction (EBHC) for CT  

SciTech Connect

Purpose: Due to x-ray beam polychromaticity and scattered radiation, attenuation measurements tend to be underestimated. Cupping and beam hardening artifacts become apparent in the reconstructed CT images. If only one material such as water, for example, is present, these artifacts can be reduced by precorrecting the rawdata. Higher order beam hardening artifacts, as they result when a mixture of materials such as water and bone, or water and bone and iodine is present, require an iterative beam hardening correction where the image is segmented into different materials and those are forward projected to obtain new rawdata. Typically, the forward projection must correctly model the beam polychromaticity and account for all physical effects, including the energy dependence of the assumed materials in the patient, the detector response, and others. We propose a new algorithm that does not require any knowledge about spectra or attenuation coefficients and that does not need to be calibrated. The proposed method corrects beam hardening in single energy CT data. Methods: The only a priori knowledge entering EBHC is the segmentation of the object into different materials. Materials other than water are segmented from the original image, e.g., by using simple thresholding. Then, a (monochromatic) forward projection of these other materials is performed. The measured rawdata and the forward projected material-specific rawdata are monomially combined (e.g., multiplied or squared) and reconstructed to yield a set of correction volumes. These are then linearly combined and added to the original volume. The combination weights are determined to maximize the flatness of the new and corrected volume. EBHC is evaluated using data acquired with a modern cone-beam dual-source spiral CT scanner (Somatom Definition Flash, Siemens Healthcare, Forchheim, Germany), with a modern dual-source micro-CT scanner (TomoScope Synergy Twin, CT Imaging GmbH, Erlangen, Germany), and with a modern C-arm CT scanner (Axiom Artis dTA, Siemens Healthcare, Forchheim, Germany). A large variety of phantom, small animal, and patient data were used to demonstrate the data and system independence of EBHC. Results: Although no physics apart from the initial segmentation procedure enter the correction process, beam hardening artifacts were significantly reduced by EBHC. The image quality for clinical CT, micro-CT, and C-arm CT was highly improved. Only in the case of C-arm CT, where high scatter levels and calibration errors occur, the relative improvement was smaller. Conclusions: The empirical beam hardening correction is an interesting alternative to conventional iterative higher order beam hardening correction algorithms. It does not tend to over- or undercorrect the data. Apart from the segmentation step, EBHC does not require assumptions on the spectra or on the type of material involved. Potentially, it can therefore be applied to any CT image.

Kyriakou, Yiannis; Meyer, Esther; Prell, Daniel; Kachelriess, Marc [Institute of Medical Physics, University of Erlangen-Nuernberg, 91052 Erlangen (Germany)

2010-10-15

115

Cold plasma processing technology makes advances  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold plasma (AKA nonthermal plasma, cool plasma, gas plasma, etc.) is a rapidly maturing antimicrobial process being developed for applications in the food industry. A wide array of devices can be used to create cold plasma, but the defining characteristic is that they operate at or near room temper...

116

Chilling Out with Colds  

MedlinePLUS

... most common cold virus, but more than 200 viruses can cause colds. Because there are so many, ... to help you feel better. Take that, cold viruses! Continue How Kids Catch Colds Mucus (say: MYOO- ...

117

Laser quench hardening of steel: Effects of superimposed elastic pre-stress on the hardness and residual stress distribution  

NASA Astrophysics Data System (ADS)

Cold drawn AISI 4140 beams were LASER surface hardened with a 2 kW CO2 LASER. Specimens were treated in the free state and while restrained in a bending fixture inducing surface tensile stresses of 94 and 230 MPa. Knoop hardness indentation was used to evaluate the through thickness hardness distribution, and a layer removal methodology was used to evaluate the residual stress distribution. Results showed the maximum surface hardness attained was not affected by pre-stress during hardening, and ranged from 513 to 676 kg/mm2. The depth of effective hardening varied at different magnitudes of pre-stress, but did not vary proportionately to the pre-stress. The surface residual stress, coinciding with the maximum compressive residual stress, increased as pre-stress was increased, from 1040 MPa for the nominally treated specimens to 1270 MPa for specimens pre-stressed to 230 MPa. The maximum tensile residual stress observed in the specimens decreased from 1060 MPa in the nominally treated specimens to 760 MPa for specimens pre-stressed to 230 MPa. Similarly, thickness of the compressive residual stress region increased and the depth at which maximum tensile residual stress occurred increased as the pre-stress during treatment was increased Overall, application of tensile elastic pre-stress during LASER hardening is beneficial to the development of compressive residual stress in AISI 4140, with minimal impact to the hardness attained from the treatment. The newly developed approach for LASER hardening may support efforts to increase both the wear and fatigue resistance of parts made from hardenable steels.

Meserve, Justin

118

A brief review of cavity swelling and hardening in irradiated copper and copper alloys  

SciTech Connect

The literature on radiation-induced swelling and hardening in copper and its alloy is reviewed. Void formation does not occur during irradiation of copper unless suitable impurity atoms such as oxygen or helium are present. Void formation occurs for neutron irradiation temperatures of 180 to 550{degree}C, with peak swelling occurring at {approximately}320{degree}C for irradiation at a damage rate of 2 {times} 10{sup {minus}7} dpa/s. The post-transient swelling rate has been measured to be {approximately}0.5%/dpa at temperatures near 400{degree}C. Dispersion-strengthened copper has been found to be very resistant to void swelling due to the high sink density associated with the dispersion-stabilized dislocation structure. Irradiation of copper at temperatures below 400{degree}C generally causes an increase in strength due to the formation of defect clusters which inhibit dislocation motion. The radiation hardening can be adequately described by Seeger's dispersed barrier model, with a barrier strength for small defect clusters of {alpha} {approx} 0.2. The radiation hardening apparently saturates for fluences greater than {approximately}10{sup 24} n/m{sup 2} during irradiation at room temperature due to a saturation of the defect cluster density. Grain boundaries can modify the hardening behavior by blocking the transmission of dislocation slip bands, leading to a radiation- modified Hall-Petch relation between yield strength and grain size. Radiation-enhanced recrystallization can lead to softening of cold-worked copper alloys at temperatures above 300{degree}C.

Zinkle, S.J.

1990-01-01

119

The effect of undrained heating on a fluid-saturated hardened cement paste  

E-print Network

The effect of undrained heating on volume change and induced pore pressure increase is an important point to properly understand the behaviour and evaluate the integrity of an oil well cement sheath submitted to rapid temperature changes. This thermal pressurization of the pore fluid is due to the discrepancy between the thermal expansion coefficients of the pore fluid and of the solid matrix. The equations governing the undrained thermo-hydro-mechanical response of a porous material are presented and the effect of undrained heating is studied experimentally for a saturated hardened cement paste. The measured value of the thermal pressurization coefficient is equal to 0.6MPa/'C. The drained and undrained thermal expansion coefficients of the hardened cement paste are also measured in the heating tests. The anomalous thermal behaviour of cement pore fluid is back analysed from the results of the undrained heating test.

Ghabezloo, Siavash; Saint-Marc, Jérémie

2008-01-01

120

Expecting the Unexpected: Radiation Hardened Software  

NASA Technical Reports Server (NTRS)

Radiation induced Single Event Effects (SEEs) are a serious problem for spacecraft flight software, potentially leading to a complete loss of mission. Conventional risk mitigation has been focused on hardware, leading to slow, expensive and outdated on-board computing devices, increased power consumption and launch mass. Our approach is to look at SEEs from a software perspective, and to explicitly design flight software so that it can detect and correct the majority of SEES. Radiation hardened flight software will reduce the significant residual residual risk for critical missions and flight phases, and enable more use of inexpensive and fast COTS hardware.

Penix, John; Mehlitz, Peter C.

2005-01-01

121

Strain Hardening of Fractal Colloidal Gels  

NASA Astrophysics Data System (ADS)

We report on experiments on the rheology of gels formed by diffusion-limited aggregation of neutrally buoyant colloidal particles. These gels form very weak solids, with the elastic modulus, G'\\(?\\), larger than the loss modulus, G''\\(?\\), and with both G'\\(?\\) and G''\\(?\\) exhibiting only a very weak frequency dependence. Upon small but finite strains ?<0.45 the elastic modulus increases roughly exponentially with ?2. We explain the observed strain hardening with the highly nonlinear elastic response of the rigid backbone of the gel to elongational deformation.

Gisler, T.; Ball, R. C.; Weitz, D. A.

1999-02-01

122

Technology Developments in Radiation-Hardened Electronics for Space Environments  

NASA Technical Reports Server (NTRS)

The Radiation Hardened Electronics for Space Environments (RHESE) project consists of a series of tasks designed to develop and mature a broad spectrum of radiation hardened and low temperature electronics technologies. Three approaches are being taken to address radiation hardening: improved material hardness, design techniques to improve radiation tolerance, and software methods to improve radiation tolerance. Within these approaches various technology products are being addressed including Field Programmable Gate Arrays (FPGA), Field Programmable Analog Arrays (FPAA), MEMS, Serial Processors, Reconfigurable Processors, and Parallel Processors. In addition to radiation hardening, low temperature extremes are addressed with a focus on material and design approaches. System level applications for the RHESE technology products are discussed.

Keys, Andrew S.; Howell, Joe T.

2008-01-01

123

Cold Stress  

MedlinePLUS

... Whenever temperatures drop decidedly below normal and as wind speed increases, heat can more rapidly leave your ... severe winter weather threatens. NOAA: National Weather Service Wind Chill Chart Additional Resources American Conference of Governmental ...

124

Cold Stowage Flight Systems  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) provides a test bed for researchers to perform science experiments in a variety of fields, including human research, life sciences, and space medicine. Many of the experiments being conducted today require science samples to be stored and transported in a temperature controlled environment. NASA provides several systems which aid researchers in preserving their science. On orbit systems provided by NASA include the Minus Eighty Laboratory freezer for ISS (MELFI), Microgravity Experiment Research Locker Incubator (MERLIN), and Glacier. These freezers use different technologies to provide rapid cooling and cold stowage at different temperature levels on board ISS. Systems available to researchers during transportation to and from ISS are MERLIN, Glacier, and Coldbag. Coldbag is a passive cold stowage system that uses phase change materials to maintain temperature. Details of these current technologies are provided along with operational experience gained to date. This paper discusses the capability of the current cold stowage hardware and how it may continue to support NASA s mission on ISS and in future exploration missions.

Campana, Sharon E.; Melendez, David T.

2011-01-01

125

Beam hardening and partial beam hardening of the bowtie filter: Effects on dosimetric applications in CT  

NASA Astrophysics Data System (ADS)

Purpose: To estimate the consequences on dosimetric applications when a CT bowtie filter is modeled by means of full beam hardening versus partial beam hardening. Method: A model of source and filtration for a CT scanner as developed by Turner et. al. [1] was implemented. Specific exposures were measured with the stationary CT X-ray tube in order to assess the equivalent thickness of Al of the bowtie filter as a function of the fan angle. Using these thicknesses, the primary beam attenuation factors were calculated from the energy dependent photon mass attenuation coefficients and used to include beam hardening in the spectrum. This was compared to a potentially less computationally intensive approach, which accounts only partially for beam hardening, by giving the photon spectrum a global (energy independent) fan angle specific weighting factor. Percentage differences between the two methods were quantified by calculating the dose in air after passing several water equivalent thicknesses representative for patients having different BMI. Specifically, the maximum water equivalent thickness of the lateral and anterior-posterior dimension and of the corresponding (half) effective diameter were assessed. Results: The largest percentage differences were found for the thickest part of the bowtie filter and they increased with patient size. For a normal size patient they ranged from 5.5% at half effective diameter to 16.1% for the lateral dimension; for the most obese patient they ranged from 7.7% to 19.3%, respectively. For a complete simulation of one rotation of the x-ray tube, the proposed method was 12% faster than the complete simulation of the bowtie filter. Conclusion: The need for simulating the beam hardening of the bow tie filter in Monte Carlo platforms for CT dosimetry will depend on the required accuracy.

Lopez-Rendon, X.; Zhang, G.; Bosmans, H.; Oyen, R.; Zanca, F.

2014-03-01

126

DESIGN TECHNIQUES FOR RADIATION HARDENED PHASE-LOCKED LOOPS  

E-print Network

of phase-lock during the operation. Digital blocks are inherently robust to the effects of radiationDESIGN TECHNIQUES FOR RADIATION HARDENED PHASE-LOCKED LOOPS Anantha Nag Nemmani, Martin Vandepas the spacecraft requires radiation hardening. This article presents the design and analysis of a radiation

Moon, Un-Ku

127

ORIGINAL PAPER Growth and frost hardening of European aspen  

E-print Network

ORIGINAL PAPER Growth and frost hardening of European aspen and backcross hybrid aspen.V. 2011 Abstract & Introduction The interactive effects of water and nitrogen (N) on frost hardiness) supply influence the growth, bud phenology and frost hardening of seven young European aspen (Populus

Paris-Sud XI, Université de

128

Hardening description for FCC materials under complex loading paths  

E-print Network

Hardening description for FCC materials under complex loading paths C. G´erard a,b,c B. Bacroix c M The present work aims at exploring self and latent hardening for FCC polycrystals under complex loading paths of face-centred cubic (FCC) crys- tals are experimentally well documented. They are related to dislocation

Boyer, Edmond

129

Radiation-Hardened Electronics for the Space Environment  

NASA Technical Reports Server (NTRS)

RHESE covers a broad range of technology areas and products. - Radiation Hardened Electronics - High Performance Processing - Reconfigurable Computing - Radiation Environmental Effects Modeling - Low Temperature Radiation Hardened Electronics. RHESE has aligned with currently defined customer needs. RHESE is leveraging/advancing SOA space electronics, not duplicating. - Awareness of radiation-related activities through out government and industry allow advancement rather than duplication of capabilities.

Keys, Andrew S.; Watson, Michael D.

2007-01-01

130

Strain hardening of low-carbon manganese steels  

Microsoft Academic Search

Low-carbon steels with a high manganese content (3–5%) are highly susceptible to strain aging, which is accompanied by hardening due to precipitation of finely dispersed cementite particles. The increase of the manganese content, due to the displacement character of the transformation of austenite, increase the amount of carbon in solution and leads to precipitation hardening similar to the intermediate transformation

V. D. Kal'ner; B. I. Beilin; L. G. Shevyakova; I. P. Arsent'eva

1980-01-01

131

Protective coatings of metal surfaces by cold plasma treatment  

NASA Technical Reports Server (NTRS)

The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.

Manory, R.; Grill, A.

1985-01-01

132

Evaluation of Microstructure and Toughness of AISI D2 Steel by Bright Hardening in Comparison with Oil Quenching  

NASA Astrophysics Data System (ADS)

AISI D2 is used widely in the manufacture of blanking and cold-forming dies, on account of its excellent hardness and wear behavior. Increasing toughness at a fixed high level of hardness is growing requirement for this kind of tool steel. Improving microstructure characteristics, especially refinement of coarse carbides, is an appropriate way to meet such requirement. In this study, morphology and size of carbides in martensite matrix were compared between two kinds of samples, which were bright hardened (quenching in hot alkaline salt bath consisting of 60% KOH and 40% NaOH) at 230 °C and quenched in oil bath at 60 °C. Results showed that morphology and distribution of carbides in samples performed by bright hardening were finer and almost spherical compared to that of oil quenched. This microstructure resulted in an improvement in toughness and tensile properties of alloy.

Torkamani, H.; Raygan, Sh.; Rassizadehghani, J.

2011-12-01

133

On the precipitation-hardening behavior of the Al-Mg-Si-Cu alloy AA6111  

NASA Astrophysics Data System (ADS)

The precipitation-hardening behavior of aluminum alloy AA6111 during artificial aging and the influence of prior natural aging on the aging behavior were investigated. The evolution of microstructure was studied using quantitative transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The evolution of the relative volume fraction of precipitates for the solution-treated alloy was determined using isothermal calorimetry and a new analysis based on the DSC technique. Quantitative TEM was also used to obtain the rate of precipitation of microscopically resolvable phases during aging at 180 °C. Three types of precipitates, i.e., unresolved Guinier-Preston (GP) zones, ??, and Q', were found to form during aging at 180 °C. The evolution of yield strength was related to the evolution of microstructure. It was found that the high hardening rate during artificial aging for the solution-treated alloy is due to the rapid precipitation of the ?? phase. Natural aging prior to artificial aging was found to decrease the rate of precipitation of ??. The slow hardening rate for the naturally aged alloy was attributed to the slower nucleation and growth of ?? phase.

Esmaeili, S.; Wang, X.; Lloyd, D. J.; Poole, W. J.

2003-03-01

134

Effects of porosity on leaching of Ca from hardened ordinary Portland cement paste  

SciTech Connect

Aiming at evaluating the effects of porosity in hardened cement paste on dissolution phenomena, we prepared hardened ordinary Portland cement (OPC), with variation in pore volume, and then leached them in deionized water. It was found that the bulk density and pore volume were affected by the dissolution of portlandite. The larger the pore volume of the sample, the more rapidly portlandite is dissolved. An electron probe microanalysis (EPMA) performed on the cross-section of the solid phase showed the 'portlandite (CH) dissolution front'. As the leaching period became longer, the CH dissolution front shifted towards the inner part. In addition, the movement of the CH dissolution front was described by the diffusion model, with consideration of the dissolution of portlandite. It was concluded that the transport of leached constituents is diffusion controlled, and the major leached constituents of hardened OPC are portlandite and C-S-H gel. Large pore, which was generated associated with the leaching of portlandite, was considered significantly to affect the diffusion of leached constituents.

Haga, Kazuko [Taiheiyo Consultant Co. Ltd., 2-4-2, Osaku, Sakura-City, Chiba 285-8655 (Japan)]. E-mail: Kazuko_Haga@grp.taiheiyo-cement.co.jp; Sutou, Shunkichi [Taiheiyo Consultant Co. Ltd., 2-4-2, Osaku, Sakura-City, Chiba 285-8655 (Japan); Hironaga, Michihiko [Central Research Institute of Electric Power Industry, 1646, Abiko, Abiko-City, Chiba 270-1194 (Japan); Tanaka, Satoru [Department of Quantum Engineering and Systems Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nagasaki, Shinya [Institute of Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2005-09-01

135

Precipitation hardening The objective of this laboratory is for you to explore the kinetics and strengthening of Al by precipitation  

E-print Network

Precipitation hardening Objective The objective of this laboratory is for you to explore the kinetics and strengthening of Al by precipitation hardening. Preparation Read sections 10 is through precipitation reactions. Precipitation hardening is the process of hardening or strengthening

Braun, Paul

136

Cold worked high alloy ultra-high strength steels with aged martensite structure  

Microsoft Academic Search

Purpose: The study on structure-property relations of heavily cold worked and aged martensite in two high- alloy structural steels was presented. The aim was to understand properties of the sheet products better and thus extend applications of the newly developed cobalt-free maraging and precipitation hardening stainless steels. Design\\/methodology\\/approach: Mechanical tests were performed on cold rolled and aged specimens. Microstructures were

S. J. Pawlak; H. J. Krzto?

137

Cold knife cone biopsy  

MedlinePLUS

A cold knife cone biopsy (conization) is surgery to remove a sample of abnormal tissue from the cervix. The cervix is ... Cold knife cone biopsy is done to detect cervical cancer or early changes that lead to cancer. A cold ...

138

Bronchitis (Chest Cold)  

MedlinePLUS

... Antibiotic Use Respiratory Illnesses Sinus Infection Sore Throat Common Cold and Runny Nose Ear Infections Bronchitis (Chest Cold) ... Tips Appropriate Treatment Summary Cough Illness/Bronchitis The Common Cold Otitis Media Pharyngitis: Treat Only Proven GAS Online ...

139

Cold Atoms  

NASA Astrophysics Data System (ADS)

This chapter and the following one address collective effects of quantum particles, that is, the effects which are observed when we put together a large number of identical particles, for example, electrons, helium-4 or rubidium-85 atoms. We shall see that quantum particles can be classified into two categories, bosons and fermions, whose collective behavior is radically different. Bosons have a tendency to pile up in the same quantum state, while fermions have a tendency to avoid each other. We say that bosons and fermions obey two different quantum statistics, the Bose-Einstein and the Fermi-Dirac statistics, respectively. Temperature is a collective effect, and in Section 5.1 we shall explain the concept of absolute temperature and its relation to the average kinetic energy of molecules. We shall describe in Section 5.2 how we can cool atoms down thanks to the Doppler effect, and explain how cold atoms can be used to improve the accuracy of atomic clocks by a factor of about 100. The effects of quantum statistics are prominent at low temperatures, and atom cooling will be used to obtain Bose-Einstein condensates at low enough temperatures, when the atoms are bosons.

Bellac, Michel Le

2014-11-01

140

Limitations of Hollomon and Ludwigson stress strain relations in assessing the strain hardening parameters  

NASA Astrophysics Data System (ADS)

It is shown that the deviation from the ideal Hollomon relation in describing the stress-strain behaviour is characteristic of all materials at low strains. The Ludwigson relation describing the deviation from the Hollomon relation at low strains is critically analysed and it is shown that the deviation at low strains is a consequence of some unknown 'plastic strain equivalent' present in the material. Stress strain curves obeying an ideal Hollomon relation as well as that of a structurally modified (prior cold worked) material were simulated and compared. The results show that the yield strength and the flow strength of a material at constant strain rate and temperature are dictated by the magnitude of the 'plastic strain equivalent' term. It is shown that this component need not necessarily mean a prior plastic strain present in the material due to prior cold work alone and that prior cold work strain will add to this. If this component is identified, the stress-strain behaviour can be adequately described by the Swift relation. It is shown that in both formalisms, the strain hardening index is a function of the yield strength of the material.

Samuel, K. G.

2006-01-01

141

Electrical conductivity is a parameter that can be used to monitor the entire hardening process of oilwell cement slurries. The theo-  

E-print Network

process of oilwell cement slurries. The theo- retical relationship among conductivity, porosity, cement and that rapid hydration will reduce the risk of gas migration. Introduction The main purposes of oilwell cements hardening process of oilwell cement slurries is important for successful cementing operations. Several

Backe, Knut

142

Transcriptome Analysis of Cold Acclimation in Barley Albina and Xantha Mutants1[W  

PubMed Central

Previously, we have shown that barley (Hordeum vulgare) plants carrying a mutation preventing chloroplast development are completely frost susceptible as well as impaired in the expression of several cold-regulated genes. Here we investigated the transcriptome of barley albina and xantha mutants and the corresponding wild type to assess the effect of the chloroplast on expression of cold-regulated genes. First, by comparing control wild type against cold-hardened wild-type plants 2,735 probe sets with statistically significant changes (P = 0.05; ?2-fold change) were identified. Expression of these wild-type cold-regulated genes was then analyzed in control and cold-hardened mutants. Only about 11% of the genes cold regulated in wild type were regulated to a similar extent in all genotypes (chloroplast-independent cold-regulated genes); this class includes many genes known to be under C-repeat binding factor control. C-repeat binding factor genes were also equally induced in mutants and wild-type plants. About 67% of wild-type cold-regulated genes were not regulated by cold in any mutant (chloroplast-dependent cold-regulated genes). We found that the lack of cold regulation in the mutants is due to the presence of signaling pathway(s) normally cold activated in wild type but constitutively active in the mutants, as well as to the disruption of low-temperature signaling pathway(s) due to the absence of active chloroplasts. We also found that photooxidative stress signaling pathway is constitutively active in the mutants. These results demonstrate the major role of the chloroplast in the control of the molecular adaptation to cold. PMID:16603669

Svensson, Jan T.; Crosatti, Cristina; Campoli, Chiara; Bassi, Roberto; Stanca, Antonio Michele; Close, Timothy J.; Cattivelli, Luigi

2006-01-01

143

Development of cosmic ray hardened power MOSFET's  

NASA Astrophysics Data System (ADS)

Developmental power DMOS (double-diffused metal-oxide-semiconductor) FETs were thoroughly characterized in a simulated cosmic-ray environment using heavy ions at the Brookhaven National Laboratory's tandem Van de Graaff accelerator facility. The primary failure mode encountered on FETs in this environment was susceptibility to single-event burnout. Burnout of the power DMOS FET was catastrophic. Another failure mode was single-event gate rupture. Although gate rupture is not as severe as burnout, its long-term effects are not known. Single-event gate rupture causes performance degradation due to increased gate leakage current. An increase in current can pose serious problems for applications that cannot compensate for the added performance degradation. Long-term reliability of the gate oxide may be affected, resulting in premature device failure. Numerous processing lots were fabricated to verify experimentally that each failure mode could be successfully minimized. Test results have shown that an n-channel, 150-V DMOS FET survived exposures to ions with linear energy transfers up to 80 MeV-sq cm/mg. Hardening approaches are discussed, including their advantages and disadvantages in relation to the FET's performance.

Titus, Jeffrey L.; Jamiolkowski, Linda S.; Wheatley, C. Frank

1989-12-01

144

Cylindrical shell buckling through strain hardening  

SciTech Connect

Recently, the authors published results of plastic buckling analysis of cylindrical shells. Ideal elastic-plastic material behavior was used for the analysis. Subsequently, the buckling analysis program was continued with the realistic stress-strain relationship of a stainless steel alloy which does not exhibit a clear yield point. The plastic buckling analysis was carried out through the initial stages of strain hardening for various internal pressure values. The computer program BOSOR5 was used for this purpose. Results were compared with those obtained from the idealized elastic-plastic relationship using the offset stress level at 0.2% strain as the yield stress. For moderate hoop stress values, the realistic stress-grain case shows a slight reduction of the buckling strength. But, a substantial gain in the buckling strength is observed as the hoop stress approaches the yield strength. Most importantly, the shell retains a residual strength to carry a small amount of axial compressive load even when the hoop stress has exceeded the offset yield strength.

Bandyopadhyay, K.; Xu, J.; Shteyngart, S. [Brookhaven National Lab., Upton, NY (United States); Gupta, D. [USDOE, Germantown, MD (United States)

1995-04-01

145

Surface Hardening: Beam Shaping And Coating Techniques  

NASA Astrophysics Data System (ADS)

The heat treatment and surface hardening of metals is a process that is of considerable interest to the metal working community. The use of lasers to accomplish this heat treatment permits one to produce results not possible with other methods. However, due to the somewhat complex nature of this process it can be confusing and it is sometimes difficult to understand exactly how to proceed: What type of beam shaping to use, what type of coatings to apply, what power levels to use, what laser, etc. In this paper , an examination of four distinct methods of beam shaping are presented. They are: 1. Focusing lens only 2. Beam scanner 3. Beam integrating mirror 4. Kaleidoscope (also known as the light pipe) Coating such as graphite paint, Manganese phosphate and black paint are used. The performance of these devices together with these various coatings, is then examined. Also factors such as the following are considered: 1. Power loss in each device 2. Energy uniformity that each produces 3. Penetrations possible 4. Limitations of each 5. Ease of installation and operation 6. Suitability of each for certain applications. Concerning the coatings, such things as: 1. Types 2. Coating thickness are studied. Each device was used in actual heat treatment with the data then examined and presented here with the hope being that specific merits and drawbacks would become evident.

Jasnowski, Kazie S.; Sanz Justes, Pedro; Zubiri Amatriain, Jose F.; Garciandia Ibanez, Fermin

1989-10-01

146

Beam Hardening Corrections in Quantitative Computed Tomography  

NASA Astrophysics Data System (ADS)

Volumetric computed tomography (VCT) is the emerging 3D NDE inspection technique that gives highest throughput and better image quality. Industrial components in general demands higher x-ray energy for inspection for which polychromatic x-ray sources are used in common. Polychromatic nature of the x-rays gives rise to non-linear effects in the VCT projection data measurements called to be the beam hardening (BH) effects. BH produces prominent artifacts in the reconstructed images thereby deteriorating the image quality. Quantitative analysis such as density quantification, dimensional analysis etc., becomes difficult with the presence of these artifacts. This paper describes the BH correction using preprocessing technique for the homogeneous materials. Selection of effective energy at which the monoenergetic linear attenuation coefficient of a particular material equals to that of the polyenergetic beam is critical for BH correction. Various methods to determine the effective energy and their consequence in the quantitative measurements have been investigated in the present study. In this paper, BH corrections for heterogeneous materials have also been explored.

Vedula, Venumadhav; Venugopal, Manoharan; Raghu, C.; Pandey, Pramod

2007-03-01

147

Effects of cold rolling deformation on microstructure, hardness, and creep behavior of high nitrogen austenitic stainless steel  

NASA Astrophysics Data System (ADS)

Effects of cold rolling deformation on the microstructure, hardness, and creep behavior of high nitrogen austenitic stainless steel (HNASS) are investigated. Microstructure characterization shows that 70% cold rolling deformation results in significant refinement of the microstructure of this steel, with its average twin thickness reducing from 6.4 ?m to 14 nm. Nanoindentation tests at different strain rates demonstrate that the hardness of the steel with nano-scale twins (nt-HNASS) is about 2 times as high as that of steel with micro-scale twins (mt-HNASS). The hardness of nt-HNASS exhibits a pronounced strain rate dependence with a strain rate sensitivity (m value) of 0.0319, which is far higher than that of mt-HNASS (m = 0.0029). nt-HNASS shows more significant load plateaus and a higher creep rate than mt-HNASS. Analysis reveals that higher hardness and larger m value of nt-HNASS arise from stronger strain hardening role, which is caused by the higher storage rate of dislocations and the interactions between dislocations and high density twins. The more significant load plateaus and higher creep rates of nt-HNASS are due to the rapid relaxation of the dislocation structures generated during loading.

Sun, Shi-Cheng; Sun, Gui-Xun; Jiang, Zhong-Hao; Ji, Chang-Tao; Liu, Jia-An; Lian, Jian-She

2014-02-01

148

Possible correlation between work-hardening and fatigue-failure  

NASA Technical Reports Server (NTRS)

Conceptual theory proposes that cyclic hardening due to non-uniform strain and stress amplitudes during testing, especially during the initial application of stress to a specimen, may correlate positively with the ultimate strength of the specimen under test.

Kettunen, P. O.; Kocks, U. F.

1969-01-01

149

Stress corrosion cracking evaluation of precipitation-hardening stainless steel  

NASA Technical Reports Server (NTRS)

Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

Humphries, T. S.; Nelson, E. E.

1970-01-01

150

HYPOTHERMIA Surviving the Cold  

E-print Network

), and fatigue are some of the main factors that can contribute to hypothermia. · Cold is the most common causeHYPOTHERMIA Surviving the Cold www.WorkSafebc.com #12;About the WCB Preventing on-the-job injury-HELP) toll-free in British Columbia. #12;1 Introduction Working in a cold environment ­ whether it be cold

Machel, Hans

151

Facts about the Common Cold  

MedlinePLUS

... Disease > Influenza > In-Depth-Resources Facts About the Common Cold What Is a Cold? Colds are minor infections ... for 10 to 40 percent of colds. Other common cold viruses include coronavirus and respiratory syncytial virus (RSV). ...

152

Strain hardening of fcc metal surfaces induced by microploughing  

SciTech Connect

Microploughing experiments were used as a method for better understanding the ploughing mechanism in gold and iridium single crystals. The plough depths ranged from 20 nm in iridium to 1,600 nm in gold. Yield stress profiles and TEM analyses indicate that both materials strain harden even when very small volumes of material are involved. Strain hardening theory, as applied to bulk material, is useful in analyzing the results.

Day, R.D.; Dickerson, R.M. [Los Alamos National Lab., NM (United States); Russell, P.E. [North Carolina State Univ., Raleigh, NC (United States)

1998-12-01

153

Finite deformation plasticity and viscoplasticity laws exhibiting nonlinear hardening rules  

Microsoft Academic Search

This paper deals with plasticity and viscoplasticity laws exhibiting nonlinear kinematic hardening as well as nonlinear isotropic\\u000a hardening rules. In Tsakmakis (1996a, b) a constitutive theory has been formulated within the framework of finite deformations,\\u000a which is based on the concept of so-called dual variables and associated time derivatives. Within two families of dual variables,\\u000a two different formulations have been

E. Diegele; W. Jansohn; Ch. Tsakmakis

2000-01-01

154

Cold Signaling and Cold Response in Plants  

PubMed Central

Plants are constantly exposed to a variety of environmental stresses. Freezing or extremely low temperature constitutes a key factor influencing plant growth, development and crop productivity. Plants have evolved a mechanism to enhance tolerance to freezing during exposure to periods of low, but non-freezing temperatures. This phenomenon is called cold acclimation. During cold acclimation, plants develop several mechanisms to minimize potential damages caused by low temperature. Cold response is highly complex process that involves an array of physiological and biochemical modifications. Furthermore, alterations of the expression patterns of many genes, proteins and metabolites in response to cold stress have been reported. Recent studies demonstrate that post-transcriptional and post-translational regulations play a role in the regulation of cold signaling. In this review article, recent advances in cold stress signaling and tolerance are highlighted. PMID:23466881

Miura, Kenji; Furumoto, Tsuyoshi

2013-01-01

155

Extracting material response from simple mechanical tests on hardening-softening-hardening viscoplastic solids  

NASA Astrophysics Data System (ADS)

Compliant foams are usually characterized by a wide range of desirable mechanical properties. These properties include viscoelasticity at different temperatures, energy absorption, recoverability under cyclic loading, impact resistance, and thermal, electrical, acoustic and radiation-resistance. Some foams contain nano-sized features and are used in small-scale devices. This implies that the characteristic dimensions of foams span multiple length scales, rendering modeling their mechanical properties difficult. Continuum mechanics-based models capture some salient experimental features like the linear elastic regime, followed by non-linear plateau stress regime. However, they lack mesostructural physical details. This makes them incapable of accurately predicting local peaks in stress and strain distributions, which significantly affect the deformation paths. Atomistic methods are capable of capturing the physical origins of deformation at smaller scales, but suffer from impractical computational intensity. Capturing deformation at the so-called meso-scale, which is capable of describing the phenomenon at a continuum level, but with some physical insights, requires developing new theoretical approaches. A fundamental question that motivates the modeling of foams is `how to extract the intrinsic material response from simple mechanical test data, such as stress vs. strain response?' A 3D model was developed to simulate the mechanical response of foam-type materials. The novelty of this model includes unique features such as the hardening-softening-hardening material response, strain rate-dependence, and plastically compressible solids with plastic non-normality. Suggestive links from atomistic simulations of foams were borrowed to formulate a physically informed hardening material input function. Motivated by a model that qualitatively captured the response of foam-type vertically aligned carbon nanotube (VACNT) pillars under uniaxial compression [2011,"Analysis of Uniaxial Compression of Vertically Aligned Carbon Nanotubes," J. Mech.Phys. Solids, 59, pp. 2227--2237, Erratum 60, 1753-1756 (2012)], the property space exploration was advanced to three types of simple mechanical tests: 1) uniaxial compression, 2) uniaxial tension, and 3) nanoindentation with a conical and a flat-punch tip. The simulations attempt to explain some of the salient features in experimental data, like 1) The initial linear elastic response. 2) One or more nonlinear instabilities, yielding, and hardening. The model-inherent relationships between the material properties and the overall stress-strain behavior were validated against the available experimental data. The material properties include the gradient in stiffness along the height, plastic and elastic compressibility, and hardening. Each of these tests was evaluated in terms of their efficiency in extracting material properties. The uniaxial simulation results proved to be a combination of structural and material influences. Out of all deformation paths, flat-punch indentation proved to be superior since it is the most sensitive in capturing the material properties.

Mohan, Nisha

156

High-Performance, Radiation-Hardened Electronics for Space Environments  

NASA Technical Reports Server (NTRS)

The Radiation Hardened Electronics for Space Environments (RHESE) project endeavors to advance the current state-of-the-art in high-performance, radiation-hardened electronics and processors, ensuring successful performance of space systems required to operate within extreme radiation and temperature environments. Because RHESE is a project within the Exploration Technology Development Program (ETDP), RHESE's primary customers will be the human and robotic missions being developed by NASA's Exploration Systems Mission Directorate (ESMD) in partial fulfillment of the Vision for Space Exploration. Benefits are also anticipated for NASA's science missions to planetary and deep-space destinations. As a technology development effort, RHESE provides a broad-scoped, full spectrum of approaches to environmentally harden space electronics, including new materials, advanced design processes, reconfigurable hardware techniques, and software modeling of the radiation environment. The RHESE sub-project tasks are: SelfReconfigurable Electronics for Extreme Environments, Radiation Effects Predictive Modeling, Radiation Hardened Memory, Single Event Effects (SEE) Immune Reconfigurable Field Programmable Gate Array (FPGA) (SIRF), Radiation Hardening by Software, Radiation Hardened High Performance Processors (HPP), Reconfigurable Computing, Low Temperature Tolerant MEMS by Design, and Silicon-Germanium (SiGe) Integrated Electronics for Extreme Environments. These nine sub-project tasks are managed by technical leads as located across five different NASA field centers, including Ames Research Center, Goddard Space Flight Center, the Jet Propulsion Laboratory, Langley Research Center, and Marshall Space Flight Center. The overall RHESE integrated project management responsibility resides with NASA's Marshall Space Flight Center (MSFC). Initial technology development emphasis within RHESE focuses on the hardening of Field Programmable Gate Arrays (FPGA)s and Field Programmable Analog Arrays (FPAA)s for use in reconfigurable architectures. As these component/chip level technologies mature, the RHESE project emphasis shifts to focus on efforts encompassing total processor hardening techniques and board-level electronic reconfiguration techniques featuring spare and interface modularity. This phased approach to distributing emphasis between technology developments provides hardened FPGA/FPAAs for early mission infusion, then migrates to hardened, board-level, high speed processors with associated memory elements and high density storage for the longer duration missions encountered for Lunar Outpost and Mars Exploration occurring later in the Constellation schedule.

Keys, Andrew S.; Watson, Michael D.; Frazier, Donald O.; Adams, James H.; Johnson, Michael A.; Kolawa, Elizabeth A.

2007-01-01

157

Process design of press hardening with gradient material property influence  

SciTech Connect

Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

Neugebauer, R. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz (Germany); Professorship for Machine Tools and Forming Technology, TU Chemnitz (Germany); Schieck, F. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz (Germany); Rautenstrauch, A. [Professorship for Machine Tools and Forming Technology, TU Chemnitz (Germany)

2011-05-04

158

Cold Stress and the Cold Pressor Test  

ERIC Educational Resources Information Center

Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This…

Silverthorn, Dee U.; Michael, Joel

2013-01-01

159

Cryptographic Path Hardening: Hiding Vulnerabilities in Software through Cryptography  

E-print Network

We propose a novel approach to improving software security called Cryptographic Path Hardening, which is aimed at hiding security vulnerabilities in software from attackers through the use of provably secure and obfuscated cryptographic devices to harden paths in programs. By "harden" we mean that certain error-checking if-conditionals in a given program P are replaced by equivalent" we mean that adversaries cannot use semi-automatic program analysis techniques to reason about the hardened program paths and thus cannot discover as-yet-unknown errors along those paths, except perhaps through black-box dictionary attacks or random testing (which we can never prevent). Other than these unpreventable attack methods, we can make program analysis aimed at error-finding "provably hard" for a resource-bounded attacker, in the same sense that cryptographic schemes are hard to break. Unlike security-through-obscurity, in Cryptographic Path Hardening we use provably-secure crypto devices to hide errors and our mathemati...

Ganesh, Vijay; Rinard, Martin

2012-01-01

160

Cold dark matter heats up.  

PubMed

A principal discovery in modern cosmology is that standard model particles comprise only 5 per cent of the mass-energy budget of the Universe. In the ?CDM paradigm, the remaining 95 per cent consists of dark energy (?) and cold dark matter. ?CDM is being challenged by its apparent inability to explain the low-density 'cores' of dark matter measured at the centre of galaxies, where centrally concentrated high-density 'cusps' were predicted. But before drawing conclusions, it is necessary to include the effect of gas and stars, historically seen as passive components of galaxies. We now understand that these can inject heat energy into the cold dark matter through a coupling based on rapid gravitational potential fluctuations, explaining the observed low central densities. PMID:24522596

Pontzen, Andrew; Governato, Fabio

2014-02-13

161

Cold dark matter heats up  

NASA Astrophysics Data System (ADS)

A principal discovery in modern cosmology is that standard model particles comprise only 5 per cent of the mass-energy budget of the Universe. In the ?CDM paradigm, the remaining 95 per cent consists of dark energy (?) and cold dark matter. ?CDM is being challenged by its apparent inability to explain the low-density `cores' of dark matter measured at the centre of galaxies, where centrally concentrated high-density `cusps' were predicted. But before drawing conclusions, it is necessary to include the effect of gas and stars, historically seen as passive components of galaxies. We now understand that these can inject heat energy into the cold dark matter through a coupling based on rapid gravitational potential fluctuations, explaining the observed low central densities.

Pontzen, Andrew; Governato, Fabio

2014-02-01

162

Hot Topics in Cold Gases  

E-print Network

Since the first experimental realization of Bose-Einstein condensation in cold atomic gases in 1995 there has been a surge of activity in this field. Ingenious experiments have allowed us to probe matter close to zero temperature and reveal some of the fascinating effects quantum mechanics has bestowed on nature. It is a challenge for mathematical physicists to understand these various phenomena from first principles, that is, starting from the underlying many-body Schr\\"odinger equation. Recent progress in this direction concerns mainly equilibrium properties of dilute, cold quantum gases. We shall explain some of the results in this article, and describe the mathematics involved in understanding these phenomena. Topics include the ground state energy and the free energy at positive temperature, the effect of interparticle interaction on the critical temperature for Bose-Einstein condensation, as well as the occurrence of superfluidity and quantized vortices in rapidly rotating gases.

Robert Seiringer

2009-08-25

163

Vitamin C and colds  

MedlinePLUS

... popular belief that vitamin C can cure the common cold , the scientific evidence for this is conflicting. Large ... B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev . 2007 Jul 18;(3): ...

164

Fructan metabolism and expression of genes coding fructan metabolic enzymes during cold acclimation and overwintering in timothy (Phleum pratense).  

PubMed

Metabolism of fructans in temperate grasses dynamically fluctuates before and during winter and is involved in the overwintering activity of plants. We monitored three candidate factors that may be involved in seasonal fructan metabolism in timothy (Phleum pratense): transcription levels of two fructosyltransferase (PpFT1 and PpFT2) genes and one fructan exohydrolase (Pp6-FEH1) gene during fall and winter and under artificially cold conditions. Functional analysis using a recombinant enzyme for PpFT2, a novel fructosyltransferase cDNA, revealed that it encoded sucrose:fructan 6-fructosyltransferase, with enzymatic properties different from previously characterized PpFT1. PpFT1 transcripts decreased from September to December as the amount of fructans increased, whereas PpFT2 transcripts increased in timothy crowns. PpFT2 was transcriptionally more induced than PpFT1 in response to cold and sucrose in timothy seedlings. A rapid increase in Pp6-FEH1 transcripts and increased monosaccharide content were observed in timothy crowns when air temperature was continuously below 0°C and plants were not covered by snow. Transcriptional induction of Pp6-FEH1 by exposure to -3°C was also observed in seedlings. These findings suggest Pp6-FEH1 involvement in the second phase of hardening. PpFT1 and PpFT2 transcription levels decreased under snow cover, whereas Pp6-FEH1 transcription levels were constant, which corresponded with the fluctuation of fructosyltransferase and fructan exohydrolase activities. Inoculation with snow mold fungi (Typhula ishikariensis) increased Pp6-FEH1 transcription levels and accelerated hydrolysis of fructans. These results suggest that transcriptional regulation of genes coding fructan metabolizing enzymes is partially involved in the fluctuation of fructan metabolism during cold acclimation and overwintering. PMID:24913052

Tamura, Ken-ichi; Sanada, Yasuharu; Tase, Kazuhiro; Yoshida, Midori

2014-07-01

165

Ion-irradiation-induced hardening in Inconel 718  

NASA Astrophysics Data System (ADS)

Inconel 718 is a material under consideration for areas in the target region of the spallation neutron source (SNS), now under construction at Oak Ridge National Laboratory (ORNL) in the US. In these positions, displacement damage from protons and neutrons will affect the mechanical properties. In addition, significant amounts of helium and hydrogen will build up in the material due to transmutation reactions. Nanoindentation measurements of solution-annealed (SA) Inconel 718 specimens, implanted with Fe-, He-, and H-ions to simulate SNS target radiation conditions, have shown that hardening occurs due to ion-induced displacement damage as well as due to the build-up of helium bubbles in the irradiated layer. Precipitation-hardened (PH) Inconel 718 also exhibited hardening by helium build-up but showed softening as a function of displacement damage due to dissolution of the ? ' and ?? precipitates.

Hunn, J. D.; Lee, E. H.; Byun, T. S.; Mansur, L. K.

2001-07-01

166

Oxide dispersion hardened mechanically alloyed materials for high temperatures  

NASA Technical Reports Server (NTRS)

The procedure of mechanical alloying makes it possible to obtain, with the aid of powder-metallurgy techniques, alloys that consist of a metallic matrix in which very fine oxide particles are dispersed. Mechanically alloyed compound powders can be used for making either forged or hot-rolled semifinished products. For these products, dispersion strengthening and precipitation hardening has been combined. At high temperatures, the strength characteristics of the alloy are determined by both dispersion hardening and by precipitation hardening processes. The effect produced by each process is independent of that due to the other. Attention is given to the principle of mechanical alloying developed by Benjamin (1970, 1976), the strength characteristics of mechanically alloyed materials, the corrosion resistance of mechanically alloyed material at high temperatures, and the preparation and characteristics of the alloy MA 6000 E.

Benjamin, J. S.; Strassburg, F. W.

1982-01-01

167

Engineering design guidelines for electromagnetic pulse hardening of naval equipment  

NASA Astrophysics Data System (ADS)

This document is intended to be used by engineers who design and manufacture shipboard equipment. It is complete in the sense that both the EMP hazard and the means of mitigating the hazard (hardening) are presented. The hazard is described, which not only discusses EMP generation in a general sense, but it also presents specific threat levels for EMP fields and transient currents and voltages included on cables and antennas which are connected to electronic equipment. This specific threat constitutes an EMP survivability criteria which must be met by the mission critical equipment. The necessary hardening technology areas include volume shielding, cable shielding and connectors, interface susceptibility analysis, terminal protective devices, upset and upset hardening, common mode rejection techniques, optical isolation, and grounding/bonding techniques. Test techniques which can verify equipment hardness are presented along with methods to observe the equipment's hardness and maintain the hardness.

Rogers, S. R.; Perala, R. A.; Rosich, R. K.; Cook, R. B.; Rudolph, T. H.

1981-07-01

168

Determination of Anisotropic Hardening of Sheet Metals by Shear Tests  

SciTech Connect

With regard to the increasing necessity of accurate material data determination for the prediction of springback, a material testing equipment has been developed and set up for the measurement of material hardening within cyclic loading. One reason for inaccurate springback predictions can be seen in a missing consideration of load reversal effects in a realistic material model description. Due to bending and unbending while the material is drawn from the flange over a radius of a deep drawing tool, a hardening takes place which leads to an expanding or shifting of the elastic area and yield locus known as isotropic, kinematic, or combined hardening. Since springback is mainly influenced by the actual stress state and a correct distinction between elastic and elastic-plastic regions, an accurate prediction of these stress and strain components is basically required to simulate springback accurately, too. The presented testing method deals with shearing of sheet metal specimens in one or more load cycles to analyze the change of yield point and yield curve. The experimental set up is presented and discussed and the results are shown for different materials such as aluminum A199.5, stainless steel X5CrNi18.10, dual phase steel DP600, and copper Cu99.99. To guarantee a wide experimental range, different sheet thicknesses were used additionally. Simulations using the finite element method were carried out to compare the measured results with calculated results from different yield criterions and different hardening laws mentioned above. It was possible to show that commonly used standard material hardening laws like isotropic and kinematic hardening laws often do not lead to accurate stress state predictions when load reversals occur. The work shows the range of occurring differences and strategies to obtain to a more reliable prediction.

Schikorra, Marco; Brosius, Alexander; Kleiner, Matthias [Institute of Forming Technology and Lightweight Construction, University of Dortmund, D-44227 Dortmund (Germany)

2005-08-05

169

EMP/EMI hardening of electrical conduit systems  

NASA Astrophysics Data System (ADS)

Properly designed and installed conduit systems can provide an effective EMP/EMI hardening technique for fixed facility construction. This report presents the results of a CERL study to provide design criteria and to conduct hardness assessments for such shielded systems. Leakage mechanisms are identified, and techniques for determining signal levels coupled to conductors inside conduit systems are presented. EMP shielding properties of conduit hardware items are analyzed and some experimental EMP hardened conduit hardware items evaluated. Finally, a number of 'in situ' test techniques for identifying and locating EMP-related defects in an installed conduit system are assessed.

Nielsen, P. H.

1981-09-01

170

EMP (electro-magnetic pulse) hardening of a relocatable radar  

NASA Astrophysics Data System (ADS)

The problem of ensuring radar survivability in a HEMP (high-altitude electromagnetic pulse) environment is examined with particular reference to experimental results obtained for the relocatable TRS 22XX radar. The approach used here is global hardening, whereby the whole system except the antenna is enclosed in a Faraday cage. Every penetration of the radar station is protected, the energy input is correctly filtered, and the signal input/output is implemented with optical fibers. Specific technological solutions for HEMP hardening are discussed.

Deville, G. J.

171

Method and apparatus for welding precipitation hardenable materials  

DOEpatents

A method for welding together members consisting of precipitation age hardened materials includes the steps of selecting a weld filler material that has substantially the same composition as the materials being joined, and an age hardening characteristic temperature age threshold below that of the aging kinetic temperature range of the materials being joined, whereby after welding the members together, the resulting weld and heat affected zone (HAZ) are heat treated at a temperature below that of the kinetic temperature range of the materials joined, for obtaining substantially the same mechanical characteristics for the weld and HAZ, as for the parent material of the members joined.

Murray, Jr., Holt (Hopewell, NJ); Harris, Ian D. (Dublin, OH); Ratka, John O. (Cleveland Heights, OH); Spiegelberg, William D. (Parma, OH)

1994-01-01

172

Method and apparatus for welding precipitation hardenable materials  

DOEpatents

A method for welding together members consisting of precipitation age hardened materials includes the steps of selecting a weld filler material that has substantially the same composition as the materials being joined, and an age hardening characteristic temperature age threshold below that of the aging kinetic temperature range of the materials being joined, whereby after welding the members together, the resulting weld and heat affected zone (HAZ) are heat treated at a temperature below that of the kinetic temperature range of the materials joined, for obtaining substantially the same mechanical characteristics for the weld and HAZ, as for the parent material of the members joined. 5 figures.

Murray, H. Jr.; Harris, I.D.; Ratka, J.O.; Spiegelberg, W.D.

1994-06-28

173

Why semiconductors must be hardened when used in space  

SciTech Connect

The natural space radiation environment presents a great challenge to present and future satellite systems with significant assets in space. Defining requirements for such systems demands knowledge about the space radiation environment and its effects on electronics and optoelectronics technologies, as well as suitable risk assessment of the uncertainties involved. For mission of high radiation levels, radiation-hardened integrated circuits will be required to preform critical mission functions. The most successful systems in space will be those that are best able to blend standard commercial electronics with custom radiation-hardened electronics in a mix that is suitable for the system of interest.

Winokur, P.S.

2000-01-04

174

Preparation of in situ hardening composite microcarriers: Calcium phosphate cement combined with alginate for bone regeneration  

PubMed Central

Novel microcarriers consisting of calcium phosphate cement and alginate were prepared for use as three-dimensional scaffolds for the culture and expansion of cells that are effective for bone tissue engineering. The calcium phosphate cement-alginate composite microcarriers were produced by an emulsification of the composite aqueous solutions mixed at varying ratios (calcium phosphate cement powder/alginate solution?=?0.8–1.2) in an oil bath and the subsequent in situ hardening of the compositions during spherodization. Moreover, a porous structure could be easily created in the solid microcarriers by soaking the produced microcarriers in water and a subsequent freeze-drying process. Bone mineral-like apatite nanocrystallites were shown to rapidly develop on the calcium phosphate cement–alginate microcarriers under moist conditions due to the conversion of the ?-tricalcium phosphate phase in the calcium phosphate cement into a carbonate–hydroxyapatite. Osteoblastic cells cultured on the microspherical scaffolds were proven to be viable, with an active proliferative potential during 14 days of culture, and their osteogenic differentiation was confirmed by the determination of alkaline phosphatase activity. The in situ hardening calcium phosphate cement–alginate microcarriers developed herein may be used as potential three-dimensional scaffolds for cell delivery and tissue engineering of bone. PMID:23836845

Park, Jung-Hui; Lee, Eun-Jung; Knowles, Jonathan C

2014-01-01

175

Defects in Carbon-Rich Ferrite of Cold-Drawn Pearlitic Steel Wires  

NASA Astrophysics Data System (ADS)

By means of X-ray line profile analysis and positron lifetime spectroscopy, densities of deformation-induced defects in carbon-rich ferrite of a series of cold-drawn pearlitic steel wires with true strains (?) up to 5 are characterized. It is shown that both the dislocation densities and the vacancy cluster concentrations increase continuously with increasing ?. On the basis of the measured defect densities, values of defect hardening are estimated. The result shows that contributions of the defect hardening to the total tensile strength of the wires reach nearly 40 pct, which is mainly ascribed to the dislocation hardening. Chemical surroundings of the defects in the carbon-rich ferrite are investigated by coincidence Doppler broadening spectroscopy. The association of carbon with the defects in ferrite is demonstrated.

Chen, Y. Z.; Csiszár, G.; Cizek, J.; Westerkamp, S.; Borchers, C.; Ungár, T.; Goto, S.; Liu, F.; Kirchheim, R.

2013-08-01

176

Cold Nuclear Matter Effects on J/{psi} Yields as a Function of Rapidity and Nuclear Geometry in d+A Collisions at {radical}(s{sub NN})=200 GeV  

SciTech Connect

We present measurements of J/{psi} yields in d+Au collisions at {radical}(s{sub NN})=200 GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/{psi} rapidity (-2.2rapidity data are inconsistent with nuclear modifications that are linear or exponential in the density weighted longitudinal thickness, such as those from the final state breakup of the bound state.

Adare, A.; Bickley, A. A.; Ellinghaus, F.; Kinney, E.; Kiriluk, K.; Linden Levy, L. A.; Nagle, J. L.; Rosen, C. A.; Seele, J.; Wysocki, M. [University of Colorado, Boulder, Colorado 80309 (United States); Afanasiev, S.; Isupov, A.; Litvinenko, A.; Malakhov, A.; Peresedov, V.; Rukoyatkin, P.; Zolin, L. [Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation); Aidala, C.; Datta, A. [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337 (United States); Ajitanand, N. N. [Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400 (United States)

2011-09-30

177

Performance comparison of radiation-hardened layout techniques  

NASA Astrophysics Data System (ADS)

Total ionizing dose (TID) effect and single event effect (SEE) from space may cause serious effects on bulk silicon and silicon on insulator (SOI) devices, so designers must pay much attention to these bad effects to achieve better performance. This paper presents different radiation-hardened layout techniques to mitigate TID and SEE effect on bulk silicon and SOI device and their corresponding advantages and disadvantages are studied in detail. Under 0.13 ?m bulk silicon and SOI process technology, performance comparisons of two different kinds of DFF circuit are made, of which one kind is only hardened in layout (protection ring for bulk silicon DFF, T-gate for SOI DFF), while the other kind is also hardened in schematic such as DICE structure. The result shows that static power and leakage of SOI DFF is lower than that of bulk silicon DFF, while SOI DFF with T-gate is a little slower than bulk silicon DFF with protection ring, which will provide useful guidance for radiation-hardened circuit and layout design.

Lingjuan, Lü; Ruping, Liu; Min, Lin; Zehua, Sang; Shichang, Zou; Genqing, Yang

2014-06-01

178

Hardening digital systems with distributed functionality: robust networks  

NASA Astrophysics Data System (ADS)

Collaborative hardening and hardware redundancy are nowadays the most interesting solutions in terms of fault tolerance achieved and low extra cost imposed to the project budget. Thanks to the powerful and cheap digital devices that are available in the market, extra processing capabilities can be used for redundant tasks, not only in early data processing (sensed data) but also in routing and interfacing1

Vaskova, Anna; Portela-Garcia, Marta; Garcia-Valderas, Mario; López-Ongil, Celia; Portilla, Jorge; Valverde, Juan; de la Torre, Eduardo; Riesgo, Teresa

2013-05-01

179

Modelling of work hardening and stress saturation in FCC metals  

Microsoft Academic Search

A work hardening theory has been developed based on a microstructural concept comprising three elements; the cell\\/subgrain size, ?, the dislocation density inside the cells, ?i, and the cell boundary dislocation density or the sub boundary misorientation, ?b or ?. The theory is based on a statistical approach to the storage of dislocations. This approach predicts that the slip length,

Erik Nes

1997-01-01

180

PRECIPITATION-HARDENING STAINLESS STEELS IN WATER-COOLED REACTORS  

Microsoft Academic Search

A study is made of the stress corrosion susceptibiity of unirradiated ; precipitation-hardening stainless steels. This study is made because of the ; failures encouatered with these materials in the Dresden and Vallecltos boiling ; water reactors. Service experience, static steam autoclave tests, and dynamic ; water and steam corrosion loop tests have demonstrated that 17-4 PH in the high-;

M. C. Rowland; W. R. Sr. Smith

1962-01-01

181

Piriformospora indica: a new biological hardening tool for micropropagated plants  

Microsoft Academic Search

Piriformospora indica is a novel plant growth promoting root endophyte. Regenerated plantlets of tobacco subjected to two different biological hardening techniques showed 88–94% survival when inoculated with P. indica as compared to 62% survival of uninoculated controls under similar conditions. The tendency of the plantlet to overcome the stress in terms of revival capacity was maximal in the case of

N. S Sahay; A Varma

1999-01-01

182

Achieving Cost-Effective Power Grid Hardening through ...  

E-print Network

that energy security efforts should start with hardening power grids. To derive an .... DC power flows on a power grid following the Kirchhoff's Law with protection, at- ... it is sufficient to prove the first part of the second statement. So, we have.

2014-12-31

183

BUSFET - A Novel Radiation-Hardened SOI Transistor  

SciTech Connect

A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology.

Dodd, P.E.; Draper, B.L.; Schwank, J.R.; Shaneyfelt, M.R.

1999-02-04

184

Enhanced Age-hardening in Aluminium-Magnesium Alloys  

Microsoft Academic Search

ALTHOUGH the solubility of magnesium in aluminium is as high as 16.8 per cent (alloy contents are expressed as atomic percentages) at 450° C (ref. 1), and decreases to an estimated value of 1 per cent at room temperature, the alloys show an abnormally small response to age-hardening. Furthermore, there is no evidence to indicate that the ageing characteristics of

I. J. Polmear; K. R. Sargant

1963-01-01

185

Micromilling of hardened tool steel for mould making applications  

Microsoft Academic Search

The implementation of replication techniques for mass production of microcomponents relies on the availability of tooling technologies for manufacturing of tools and moulds. Micromilling is a suitable technique for manufacturing of microstructures characterized by high aspect ratios and complex geometries as those characterizing injection moulding moulds. The realization of the micromilling process in connection with hardened tool steel as workpiece

G. Bissacco; H. N. Hansen; L. De Chiffre

2005-01-01

186

STRESS BEHAVIOUR IN A POWER-LAW HARDENING MATERIAL  

E-print Network

is characteristic for metals with extended strain hardening capability and low proportionality limits. If the elastic body has reentrant corners and edges or the material pa- rameters are jumping, then high stresses-fields [10], [24]. Finally, we present some regularity results for elastic fields in composites with varying

Knees, Dorothee

187

Cold Nuclear Matter Effects on J\\/psi Yields as a Function of Rapidity and Nuclear Geometry in Deuteron-Gold Collisions at sqrt(s_NN) = 200 GeV  

Microsoft Academic Search

We present measurements of J\\/psi yields in d+Au collisions at sqrt(s_NN) =\\u000a200 GeV recorded by the PHENIX experiment and compare with yields in p+p\\u000acollisions at the same energy per nucleon-nucleon collision. The measurements\\u000acover a large kinematic range in J\\/psi rapidity (-2.2 < y < 2.4) with high\\u000astatistical precision and are compared with two theoretical models: one

A. Adare; S. Afanasiev; C. Aidala; N. N. Ajitanand; Y. Akiba; H. Al-Bataineh; J. Alexander; A. Angerami; K. Aoki; N. Apadula; L. Aphecetche; Y. Aramaki; J. Asai; E. T. Atomssa; R. Averbeck; T. C. Awes; B. Azmoun; V. Babintsev; M. Bai; G. Baksay; L. Baksay; A. Baldisseri; K. N. Barish; P. D. Barnes; B. Bassalleck; A. T. Basye; S. Batsouli; V. Baublis; C. Baumann; A. Bazilevsky; S. Belikov; R. Belmont; R. Bennett; A. Berdnikov; Y. Berdnikov; J. H. Bhom; A. A. Bickley; D. S. Blau; J. G. Boissevain; J. S. Bok; H. Borel; K. Boyle; M. L. Brooks; H. Buesching; V. Bumazhnov; G. Bunce; S. Butsyk; C. M. Camacho; S. Campbell; A. Caringi; B. S. Chang; W. C. Chang; J.-L. Charvet; C.-H. Chen; S. Chernichenko; C. Y. Chi; M. Chiu; I. J. Choi; J. B. Choi; R. K. Choudhury; P. Christiansen; T. Chujo; P. Chung; A. Churyn; O. Chvala; V. Cianciolo; Z. Citron; B. A. Cole; Z. Conesa del Valle; M. Connors; P. Constantin; M. Csanád; T. CsörgHo; T. Dahms; S. Dairaku; I. Danchev; K. Das; A. Datta; G. David; M. K. Dayananda; A. Denisov; D. d'Enterria; A. Deshpande; E. J. Desmond; K. V. Dharmawardane; O. Dietzsch; A. Dion; M. Donadelli; L. D Orazio; O. Drapier; A. Drees; K. A. Drees; A. K. Dubey; J. M. Durham; A. Durum; D. Dutta; V. Dzhordzhadze; S. Edwards; Y. V. Efremenko; F. Ellinghaus; T. Engelmore; A. Enokizono; H. En'yo; S. Esumi; K. O. Eyser; B. Fadem; D. E. Fields; M. Finger; F. Fleuret; S. L. Fokin; Z. Fraenkel; J. E. Frantz; A. Franz; A. D. Frawley; K. Fujiwara; Y. Fukao; T. Fusayasu; I. Garishvili; A. Glenn; H. Gong; M. Gonin; J. Gosset; Y. Goto; R. Granier de Cassagnac; N. Grau; S. V. Greene; G. Grim; M. Grosse Perdekamp; T. Gunji; H.-Å. Gustafsson; A. Hadj Henni; J. S. Haggerty; K. I. Hahn; H. Hamagaki; J. Hamblen; J. Hanks; R. Han; E. P. Hartouni; K. Haruna; E. Haslum; R. Hayano; M. Heffner; T. K. Hemmick; T. Hester; X. He; J. C. Hill; M. Hohlmann; W. Holzmann; K. Homma; B. Hong; T. Horaguchi; D. Hornback; S. Huang; T. Ichihara; R. Ichimiya; H. Iinuma; Y. Ikeda; K. Imai; J. Imrek; M. Inaba; D. Isenhower; M. Ishihara; T. Isobe; M. Issah; A. Isupov; D. Ivanischev; Y. Iwanaga; B. V. Jacak J. Jia; X. Jiang; J. Jin; B. M. Johnson; T. Jones; K. S. Joo; D. Jouan; D. S. Jumper; F. Kajihara; S. Kametani; N. Kamihara; J. Kamin; J. H. Kang; J. Kapustinsky; K. Karatsu; M. Kasai; D. Kawall; M. Kawashima; A. V. Kazantsev; T. Kempel; A. Khanzadeev; K. M. Kijima; J. Kikuchi; A. Kim; B. I. Kim; D. H. Kim; D. J. Kim; E. J. Kim; S. H. Kim; Y.-J. Kim; E. Kinney; K. Kiriluk; Á. Kiss; E. Kistenev; J. Klay; C. Klein-Boesing; L. Kochenda; B. Komkov; M. Konno; J. Koster; A. Kozlov; A. Král; A. Kravitz; G. J. Kunde; K. Kurita; M. Kurosawa; M. J. Kweon; Y. Kwon; G. S. Kyle; R. Lacey; Y. S. Lai; J. G. Lajoie; D. Layton; A. Lebedev; D. M. Lee; J. Lee; K. B. Lee; K. S. Lee; T. Lee; M. J. Leitch; M. A. L. Leite; B. Lenzi; P. Lichtenwalner; P. Liebing; L. A. Linden Levy; T. Liška; A. Litvinenko; H. Liu; M. X. Liu; X. Li; B. Love; D. Lynch; C. F. Maguire; Y. I. Makdisi; A. Malakhov; M. D. Malik; V. I. Manko; E. Mannel; Y. Mao; L. Mašek; H. Masui; F. Matathias; M. McCumber; P. L. McGaughey; D. McGlinchey; N. Means; B. Meredith; Y. Miake; T. Mibe; A. C. Mignerey; P. Mikeš; K. Miki; A. Milov; M. Mishra; J. T. Mitchell; A. K. Mohanty; H. J. Moon; Y. Morino; A. Morreale; T. V. Moukhanova; D. Mukhopadhyay; T. Murakami; J. Murata; S. Nagamiya; J. L. Nagle; M. Naglis; M. I. Nagy; I. Nakagawa; Y. Nakamiya; K. R. Nakamura; T. Nakamura; K. Nakano; S. Nam; J. Newby; M. Nguyen; M. Nihashi; T. Niita; R. Nouicer; A. S. Nyanin; C. Oakley; E. O'Brien; S. X. Oda; C. A. Ogilvie; K. Okada; M. Oka; Y. Onuki; A. Oskarsson; M. Ouchida; K. Ozawa; R. Pak; A. P. T. Palounek; V. Pantuev; V. Papavassiliou; I. H. Park; S. K. Park; W. J. Park; S. F. Pate; H. Pei; J.-C. Peng; H. Pereira; V. Peresedov; D. Yu. Peressounko; R. Petti; C. Pinkenburg; R. P. Pisani; M. Proissl; M. L. Purschke; A. K. Purwar; H. Qu; J. Rak; A. Rakotozafindrabe; I. Ravinovich; K. F. Read; S. Rembeczki; K. Reygers; V. Riabov; Y. Riabov; E. Richardson; D. Roach; G. Roche; S. D. Rolnick; M. Rosati; C. A. Rosen; S. S. E. Rosendahl; P. Rosnet; P. Rukoyatkin; P. Ruži?ka; V. L. Rykov; B. Sahlmueller; N. Saito; T. Sakaguchi; S. Sakai; K. Sakashita; V. Samsonov; S. Sano; T. Sato; S. Sawada; K. Sedgwick; J. Seele; R. Seidl; A. Yu. Semenov; V. Semenov; R. Seto; D. Sharma; I. Shein; T.-A. Shibata; K. Shigaki; M. Shimomura; K. Shoji; P. Shukla; A. Sickles; C. L. Silva; D. Silvermyr; C. Silvestre; K. S. Sim; B. K. Singh; C. P. Singh; V. Singh; M. Slune?ka; A. Soldatov; R. A. Soltz; W. E. Sondheim; S. P. Sorensen; I. V. Sourikova; F. Staley; P. W. Stankus; E. Stenlund; M. Stepanov; A. Ster; S. P. Stoll; T. Sugitate; C. Suire; A. Sukhanov; J. Sziklai; E. M. Takagui; A. Taketani; R. Tanabe; Y. Tanaka; S. Taneja; K. Tanida; M. J. Tannenbaum; S. Tarafdar; A. Taranenko; P. Tarján; H. Themann; D. Thomas

2010-01-01

188

Open photoacoustic cell for thermal diffusivity measurements of a fast hardening cement used in dental restoring  

NASA Astrophysics Data System (ADS)

Thermal diffusivity and conductivity of dental cements have been studied using open photoacoustic cell (OPC). The samples consisted of fast hardening cement named CER, developed to be a root-end filling material. Thermal characterization was performed in samples with different gel/powder ratio and particle sizes and the results were compared to the ones from commercial cements. Complementary measurements of specific heat and mass density were also performed. The results showed that the thermal diffusivity of CER tends to increase smoothly with gel volume and rapidly against particle size. This behavior was linked to the pores size and their distribution in the samples. The OPC method was shown to be a valuable way in deriving thermal properties of porous material.

Astrath, F. B. G.; Astrath, N. G. C.; Baesso, M. L.; Bento, A. C.; Moraes, J. C. S.; Santos, A. D.

2012-01-01

189

Nanoscale characterization of the biomechanical hardening of bovine zona pellucida  

PubMed Central

The zona pellucida (ZP) is an extracellular membrane surrounding mammalian oocytes. The so-called zona hardening plays a key role in fertilization process, as it blocks polyspermy, which may also be caused by an increase in the mechanical stiffness of the ZP membrane. However, structural reorganization mechanisms leading to ZP's biomechanical hardening are not fully understood yet. Furthermore, a correct estimate of the elastic properties of the ZP is still lacking. Therefore, the aim of the present study was to investigate the biomechanical behaviour of ZP membranes extracted from mature and fertilized bovine oocytes to better understand the mechanisms involved in the structural reorganization of the ZP that may lead to the biomechanical hardening of the ZP. For that purpose, a hybrid procedure is developed by combining atomic force microscopy nanoindentation measurements, nonlinear finite element analysis and nonlinear optimization. The proposed approach allows us to determine the biomechanical properties of the ZP more realistically than the classical analysis based on Hertz's contact theory, as it accounts for the nonlinearity of finite indentation process, hyperelastic behaviour and material heterogeneity. Experimental results show the presence of significant biomechanical hardening induced by the fertilization process. By comparing various hyperelastic constitutive models, it is found that the Arruda–Boyce eight-chain model best describes the biomechanical response of the ZP. Fertilization leads to an increase in the degree of heterogeneity of membrane elastic properties. The Young modulus changes sharply within a superficial layer whose thickness is related to the characteristic distance between cross-links in the ZP filamentous network. These findings support the hypothesis that biomechanical hardening of bovine ZP is caused by an increase in the number of inter-filaments cross-links whose density should be higher in the ZP inner side. PMID:22675161

Boccaccio, Antonio; Frassanito, Maria Cristina; Lamberti, Luciano; Brunelli, Roberto; Maulucci, Giuseppe; Monaci, Maurizio; Papi, Massimiliano; Pappalettere, Carmine; Parasassi, Tiziana; Sylla, Lakamy; Ursini, Fulvio; De Spirito, Marco

2012-01-01

190

Effect of CNTs on precipitation hardening behavior of CNT/AlCu composites  

E-print Network

Effect of CNTs on precipitation hardening behavior of CNT/Al­Cu composites Dong H. Nam a , Yun K June 2012 A B S T R A C T The precipitation hardening behavior of CNT/Al­Cu composites was investigated accelerated the precipitation hardening behavior of CNT/Al­Cu composites due to the generation of excess

Hong, Soon Hyung

191

Environmental control of cold hardiness in woody plants.  

PubMed

The development of cold hardiness in 2 woody plant species (Acer negundo and Viburnum plicatum tomentosum) was shown to be independent of the induction of bud dormancy. Substantial hardiness levels were obtained under controlled conditions with long days and certain low temperatures-without dormancy development as a prerequisite.Low temperatures given during the dark period with long days induced hardiness to a level not significantly different from that of short days. Giving plants continuous 10 degrees temperatures under long days forced plants to harden as if they were under short days, even though they were not dormant.Development of hardiness was shown to be a photoperiodic response. Increasing weeks of short days, followed by a low temperature hardening period in darkness, brought about a progressive increase in hardiness. The short day stimulus could be reversed by long days. Following 6 weeks of short days, the rate of hardening in darkness at 5 degrees was over twice that of plants previously exposed to long days. PMID:16656639

Irving, R M; Lanphear, F O

1967-09-01

192

Purification and characterization of glutathione reductase isozymes specific for the state of cold hardiness of red spruce.  

PubMed Central

Isozymes of glutathione reductase (GR) have been purified from red spruce (Picea rubens Sarg.) needles. Two isozymes could be separated by anion-exchange chromatography from both nonhardened or cold-hardened tissue. Based on chromatographic elution profiles, the isozymes were designated GR-1NH and GR-2NH in preparations from nonhardened needles, and GR-1H and GR-2H in preparations from hardened needles. N-terminal sequencing and immunological data with antisera obtained against GR-1H and GR-2H established that the isozymes from hardened needles are different gene products and show significant structural differences from each other. Chromatographic, electrophoretic, and immunological data revealed only minor differences between GR-2NH and GR-2H, and it is concluded that these isozymes are very similar or identical. Anion-exchange chromatography and native polyacrylamide gel electrophoresis also established that GR-1NH and GR-1H are different proteins. From these data we conclude that GR-1H is a distinct gene product, present only in hardened needles. Therefore, GR-1H can be considered to be a cold-hardiness-specific GR isozyme, and GR-1NH can be considered to be specific for nonhardened needles. It is proposed that GR-1H is a cold-acclimation protein. PMID:8029350

Hausladen, A; Alscher, R G

1994-01-01

193

Analysis of cold and hot isostatic compaction of spherical particles  

SciTech Connect

Cold and hot isostatic compaction of monosized metal powders is analyzed within the framework of viscoplastic theory for particles packed both in a regular and a random manner. The problem of local contact between spherical particles is analyzed first by drawing upon recent detailed numerical studies of spherical indentation of power law plastic and creeping solids. The compaction process is then modelled as a self-similar contraction of unit (average) cells, in contrast to commonly used phenomenological assumptions, yielding a simple but rigorous relation between the densification density and center-to-center approach of adjacent powder particles. The resulting densification formulae are easy to apply and the influence of hardening and creep parameters appears in concise form. Predictions are compared with discriminating experimental data for a variety of different powder materials, both in the cold and a hot state, and the agreement is good for a relative density increase of up to 30%.

Larsson, P.L.; Biwa, S.; Storaakers, B. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid Mechanics] [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid Mechanics

1996-09-01

194

A dnaN Plasmid Shuffle Strain for Rapid In Vivo Analysis of Mutant Escherichia coli ? Clamps Provides Insight Into the Role of Clamp in umuDC-Mediated Cold Sensitivity  

PubMed Central

The E. coli umuDC gene products participate in two temporally distinct roles: UmuD2C acts in a DNA damage checkpoint control, while UmuD'2C, also known as DNA polymerase V (Pol V), catalyzes replication past DNA lesions via a process termed translesion DNA synthesis. These different roles of the umuDC gene products are managed in part by the dnaN-encoded ? sliding clamp protein. Co-overexpression of the ? clamp and Pol V severely blocked E. coli growth at 30°C. We previously used a genetic assay that was independent of the ability of ? clamp to support E. coli viability to isolate 8 mutant clamp proteins (?Q61K, ?S107L, ?D150N, ?G157S, ?V170M, ?E202K, ?M204K and ?P363S) that failed to block growth at 30°C when co-overexpressed with Pol V. It was unknown whether these mutant clamps were capable of supporting E. coli viability and normal umuDC functions in vivo. The goals of this study were to answer these questions. To this end, we developed a novel dnaN plasmid shuffle assay. Using this assay, ?D150N and ?P363S were unable to support E. coli viability. The remaining 6 mutant clamps, each of which supported viability, were indistinguishable from ?+ with respect to umuDC functions in vivo. In light of these findings, we analyzed phenotypes of strains overexpressing either ? clamp or Pol V alone. The strain overexpressing ?+, but not those expressing mutant ? clamps, displayed slowed growth irrespective of the incubation temperature. Moreover, growth of the Pol V-expressing strain was modestly slowed at 30°, but not 42°C. Taken together, these results suggest the mutant clamps were identified due to their inability to slow growth rather than an inability to interact with Pol V. They further suggest that cold sensitivity is due, at least in part, to the combination of their individual effects on growth at 30°C. PMID:24896652

Babu, Vignesh M. P.; Sutton, Mark D.

2014-01-01

195

Cold stress and the cold pressor test.  

PubMed

Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This activity is easily adapted to an inquiry format that asks students to go to the scientific literature to learn about the test and then design a protocol for carrying out the test in classmates. The data collected are ideal for teaching graphical presentation of data and statistical analysis. PMID:23471256

Silverthorn, Dee U; Michael, Joel

2013-03-01

196

Surface hardening of titanium alloys with melting depth controlled by heat sink  

DOEpatents

A process for forming a hard surface coating on titanium alloys includes providing a piece of material containing titanium having at least a portion of one surface to be hardened. The piece having a portion of a surface to be hardened is contacted on the backside by a suitable heat sink such that the melting depth of said surface to be hardened may be controlled. A hardening material is then deposited as a slurry. Alternate methods of deposition include flame, arc, or plasma spraying, electrodeposition, vapor deposition, or any other deposition method known by those skilled in the art. The surface to be hardened is then selectively melted to the desired depth, dependent on the desired coating thickness, such that a molten pool is formed of the piece surface and the deposited hardening material. Upon cooling a hardened surface is formed.

Oden, Laurance L. (Albany, OR); Turner, Paul C. (Albany, OR)

1995-01-01

197

Cold Air Damming  

NSDL National Science Digital Library

Cold Air Damming is part of the Mesoscale Meteorology Primer series. This module first presents a Navy forecast scenario prior to the development of a major cold air damming (CAD) event along the east slopes of the Appalachian Mountains. Then, from a conceptual standpoint, the classic CAD scenario is described in detail, both from an observational and modeling standpoint.

2014-09-14

198

Stress and Distortion Evolution During Induction Case Hardening of Tube  

NASA Astrophysics Data System (ADS)

Simulation of stresses during heat treatment relates usually to furnace heating. Induction heating provides a very different evolution of temperature in the part and therefore different stresses. This may be positive for service properties or negative, reducing component strength or even causing cracks. A method of coupled simulation between electromagnetic, thermal, structural, stress, and deformation phenomena during induction tube hardening is described. Commercial software package ELTA is used to calculate the power density distribution in the load resulting from the induction heating process. The program DANTE is used to predict temperature distribution, phase transformations, stress state, and deformation during heating and quenching. Analyses of stress and deformation evolution were made on a simple case of induction hardening of external (1st case) and internal (2nd case) surfaces of a thick-walled tubular body.

Nemkov, Valentin; Goldstein, Robert; Jackowski, John; Ferguson, Lynn; Li, Zhichao

2013-07-01

199

Vacancy-induced hardening in Fe-Al alloys  

NASA Astrophysics Data System (ADS)

Hardness of Fe-Al alloys shows a non-trivial dependence on chemical composition and thermal treatment of samples and cannot be fully explained by consideration of intermetallic phases formed according to the equilibrium phase diagram of Fe-Al system. Hardening in Fe-Al alloys caused by quenched-in non-equilibrium vacancies was studied in this work. Non-equilibrium vacancies introduced into the alloys by quenching from 1000 °C were detected by means of positron annihilation spectroscopy. The concentration of quenched-in vacancies was found to strongly increase with increasing Al content from ? 10-5 at.-1 in the alloy with cAl = 18 at. % up to ? 10-1 at.-1 in the alloy with cAl = 45 at. %. Comparison of the vacancy concentration and the Vickers microhardness revealed that hardening is proportional to square root of concentration of quenched-in vacancies.

Luká?, F.; ?ížek, J.; Procházka, I.; Jirásková, Y.; Jani?kovi?, D.; Anwand, W.; Brauer, G.

2013-06-01

200

Precipitation hardening in a dental low-gold alloy.  

PubMed

Age-hardening characteristics in a dental low-gold alloy composed of 40.0 wt% Au-35.0 wt% Ag-7.9 wt% Pd-7.0 wt% Cu-5.0 wt% In-3.5 wt% Zn-1.5 wt% Sn, were investigated by means of the hardness test, XRD study, SEM observations and EPMA. The following results were obtained. The age-hardening was characterized by a precipitation of Cu-rich alpha2 phase in the a phase. The softening that occurred following prolonged ageing was due to the heterogeneous formation of the fine nodular precipitates composed of the Ag-rich alpha1 phase and the Cu-rich alpha2 phase at the grain boundaries of the a phase. PMID:12790292

Kim, Hyung-Il; Park, Young-Hwan; Lee, Hee-Kyung; Seol, Hyo-Joung; Shiraishi, Takanobu; Hisatsune, Kunihiro

2003-03-01

201

Radiation-hardened microcomputers for robotics and teleoperated systems  

SciTech Connect

Future applications of robots for Environmental Restoration and Waste Management will require radiation-hardened high-performance 32-bit microcomputers for advanced control and sensory integration. With the winding down of many programs sponsored by the U.S. Department of Defense, it is important to select carefully microprocessors for projects that will mature (or will require continued support) several years in the future. Other studies have examined a broad range of radiation-hardened microprocessors available. However, at present there are only six candidate rad-hard 32-bit processors that should be considered for long-range planning for high-performance systems. For U.S. Department of Energy applications, it is also important to consider efforts at standardization that require the use of the VxWorks operating system and hardware based on the VMEbus.

Sias, F.R. Jr. (Clemson Univ., SC (United States)); Tulenko, J.S. (Univ. of Florida, Gainesville, FL (United States))

1993-01-01

202

Sequential circuit design for radiation hardened multiple voltage integrated circuits  

DOEpatents

The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

Clark, Lawrence T. (Phoenix, AZ); McIver, III, John K. (Albuquerque, NM)

2009-11-24

203

Setting Reaction and Hardening of an Apatitic Calcium Phosphate Cement  

Microsoft Academic Search

The combination of self-setting and biocompatibility makes calcium phosphate cements potentially useful materials for a variety of dental applications. The objective of this study was to investigate the setting and hardening mechanisms of a cement-type reaction leading to the formation of calcium-deficient hydroxyapatite at low temperature. Reactants used were a-tricalcium phosphate containing 17 wt% ?-tricalcium phosphate, and 2 wt% of

M. P. Ginebra; E. Fernández; E. A. P. De Maeyer; R. M. H. Verbeeck; M. G. Boltong; J. Ginebra; F. C. M. Driessens; J. A. Planell

1997-01-01

204

Hardening and Securing Linux OS Syllabus and Course Outline  

NSDL National Science Digital Library

The Center for Systems Security and Information Assurance (CSSIA) provides this zip file with a course outline and syllabus document for a course on hardening and securing Linux OS. The syllabus is a sample one, which could be adapted to suit any course on this topic. It includes information about the course, required textbook, course goals, outline, classroom policies and grading policies. An additional document with a detailed course outline is also included in the zip file.

205

Beam Hardening Correction for Middle-Energy Industrial Computerized Tomography  

Microsoft Academic Search

In this paper, a new beam hardening correction (BHC) method for middle-energy industrial computerized tomography (CT) is presented. Our method is derived from linearization and is straightforward without iteration involved. The linearization is commonly used as a preprocessing method in BHC. Conventionally, only one-material objects can be conveniently corrected by linearization. In industrial CT, two-material objects, especially cylinders with high-Z

Hewei Gao; L. Zhang; Zhiqiang Chen; Yuxiang Xing; Shuanglei Li

2006-01-01

206

Gamma prime hardened nickel--iron based superalloy  

Microsoft Academic Search

A low swelling, gamma prime hardened nickel--iron base superalloy useful for fast reactor duct and cladding applications is described having from about 7.0 to about 10.5 weight percent (wt%) chromium, from about 24 to about 35 wt% nickel, from about 1.7 to 2.5 wt% titanium, from about 0.3 to about 1.0 wt% aluminum, from about 2.0 to about 3.3 wt%

Korenko

1978-01-01

207

Gamma prime hardened nickel-iron based superalloy  

Microsoft Academic Search

A low swelling, gamma prime hardened nickel-iron base superalloy useful for fast reactor duct and cladding applications is described having from about 7.0 to about 10.5 weight percent (wt%) chromium, from about 24 to about 35 wt% nickel, from about 1.7 to about 2.5 wt% titanium, from about 0.3 to about 1.0 wt% aluminum, from about 2.0 to about 3.3

Korenko; Michael K

1978-01-01

208

Perspective polymers hardened media for aluminum alloys and steels  

SciTech Connect

The topicality of the problem lies in decreasing shrinkage and residual stresses under heat treatment of the details made of aluminum alloys and steels. Both metallogists and chemists worked together to solve the problem. Universal non-contact media on the water basis with polymers of low concentration as additatives were developed. It decreased shrinkage and residual stresses effective and provided with velocity of cooling heat treatment necessary for remaining mechanical characteristics under hardening of the details made of aluminum alloys and steels.

Bedarev, A.S.; Muraviev, V.V.; Yermolaeva, Z.I. [Siberian State Academy of Railways, Novosibirsk (Russian Federation)

1996-12-31

209

Finite deformation plasticity and viscoplasticity laws exhibiting nonlinear hardening rules  

Microsoft Academic Search

We consider two finite deformation plasticity models, which differ mainly in the evolution equation governing the response\\u000a of kinematic hardening. Both models reduce to the same constitutive law in the case of small deformations. The aim of the\\u000a paper is to discuss these models by calculating the predicted responses for some representative loading conditions. The numerical\\u000a calculations needed are performed

E. Diegele; St. Hartmann; Ch. Tsakmakis

2000-01-01

210

Blast response of a hardened Army ISO shelter  

SciTech Connect

A prototype shelter was designed to withstand a blast loading corresponding to a 10.0 psi (68.9 kPa) incident overpressure. The hardened shelter was then constructed, instrumented and subjected to a simulated nuclear blast loading. Test results demonstrated that a design featuring shear stiffened sandwich panels with aluminum face materials could withstand a nominal 10.0 psi incident shock loading.

Milligan, R.W.; Lush, A.; Crenshaw, W.L.

1982-09-01

211

Surface modification on PMMA : PVDF polyblend: hardening under chemical environment  

Microsoft Academic Search

The influence of chemical environment on polymers include the surface alteration as well as other deep modifications in surface\\u000a layers. The surface hardening, as an effect of organic liquids on poly(methyl methacrylate): poly(vinylidene fluoride) (PMMA:\\u000a PVDF), which is one of the few known miscible blends, has been detected using microhardness testing. Organic liquids like\\u000a acetone, toluene, xylene and benzene were

R. Bajpai; V. Mishra; Pragyesh Agrawal; S. C. Datt

2002-01-01

212

Numerical simulation of burst defects in cold extrusion process  

NASA Astrophysics Data System (ADS)

The formation of the central bursts in axisymmetric cold extrusion is numerically simulated by using 2D finite element analysis (FEA) accounting for the mixed isotropic and kinematic hardening together with the ductile damage effect. The coupling between the ductile damage and the elastoplastic constitutive equations is formulated in the framework of the thermodynamics of irreversible processes together with the Continuum Damage Mechanics (CDM) theory. An isotropic ductile damage model is fully coupled with elastoplastic constitutive equations including non linear isotropic and kinematic hardening. A modified ductile damage criterion based on linear combination of the stress tensor invariants is used in order to predict the occurrence of micro-crack initiation as a discontinuous central bursts along the bar axis. The implicit integration scheme of the fully coupled constitutive equations and the Dynamic Explicit resolution scheme to solve the associated initial and boundary value problem are outlined. Application is made to the prediction of the chevron shaped cracks in cold extrusion of a round bar. The effect of various process parameters, as the diameter reduction ratio, the die semi-angle, the friction coefficient and the material ductility, on the central bursts occurrence are discussed.

Labergère, C.; Lestriez, P.; Saanouni, K.

2007-05-01

213

Simulation of Stress and Strain for Induction-Hardening Applications  

NASA Astrophysics Data System (ADS)

The possibility to manage stress and strain in hardened parts might be beneficial for a number of induction-hardening applications. The most important of these benefits are the improvement of fatigue strength, avoidance of cracks, and minimization of distortion. An appropriate and powerful way to take the stress and strain into account during the development of a process is to make use of computer simulations. In-house developed and commercial software packages have been coupled to incorporate the electromagnetic task into the calculations. The simulations have been performed followed by analysis of the results. The influences of two different values of quenching intensity, strength of initial material structure, strength of austenite, surface power density-frequency-time combination, and workpiece diameter on the residual stress are studied. The influence of quenching intensity is confirmed by the series of experiments representing the external hardening of a cylinder with eight variations of quenching intensity. Measured by x-rays, the values of surface tangential stress are used as a dataset for verification of the model being used for analyses.

Ivanov, Dmitry; Markegård, Leif; Asperheim, John Inge; Kristoffersen, Hans

2013-11-01

214

Strain hardening behavior of ARMCO iron processed by ECAP  

NASA Astrophysics Data System (ADS)

The strain hardening behavior of an ARMCO iron processed by ECAP at room temperature up to sixteen passes following route Bc was investigated through Hollomon and differential Crussard-Jaoul models. Results indicate that the Hollomon analysis shows some deviations from the experimentally determined true stress - true strain curves while the differential Crussard-Jaoul analysis based on the Ludwik equation and the modified Crussard- Jaoul analysis based on the Swift equation fit better when two work hardening exponents are considered. As expected, the strength of the material increased with the number of ECAP passes. Indeed the ultimate tensile stress reached a maximum of ~900MPa after 16 passes, which is more than three times higher than the UTS of the annealed material. Nevertheless, the strain hardening capacity of the material was reduced in comparison with the material without severe plastic deformation. For that reason the tensile ductility was also reduced at increasing ECAP passes. The increase in strength was attributed to the reduction of the grain size through refined sub-grains with high density of dislocations. After sixteenth passes the original grain size (namely 70 mm) was reduced down to 300 to 400 nm observing a good correspondence with the Hall-Petch relationship. The microstructural analysis, carried out by EBSD, showed an increasing amount in the fraction of high Angle Grain Boundaries (HAGB) after 1 pass due to the regeneration of the microstructure with a smaller grain size.

Muñoz Bolaños, J. A.; Higuera Cobos, O. F.; Cabrera Marrero, J. M.

2014-08-01

215

Influence of hardening and surface modification of endourological wires on corrosion resistance.  

PubMed

Guide wires with suitable functional characteristics are of crucial importance for proper urological treatment. This study presents an analysis of the effect of work hardening taking place in the process of wire cold drawing and the effect of surface modification by means of electrochemical polishing and chemical passivation on the resistance of wires made of X10CrNi18-8 steel used in urology. Corrosion resistance was evaluated on the grounds of the registered anodic polarisation curves by means of potentiodynamic method. The tests were made in solution simulating human urine. Anodic polarisation curves were presented for selected wire diameters. Mechanical properties were tested in a static uniaxial tensile test. The course of flow curve as well as mathematical form of flow stress function were determined. Curves presenting the relation of polarisation resistance as a function of strain applied in the drawing process are given. The tests carried out show that surface modification by means of electrochemical polishing and then chemical passivation of wires used in endourological treatment is fundamental. PMID:23140197

Walke, Witold; Przondziono, Joanna

2012-01-01

216

Formation quality optimization of laser hot wire cladding for repairing martensite precipitation hardening stainless steel  

NASA Astrophysics Data System (ADS)

Laser cladding is an advantaged repairing technology due to its low heat input and high flexibility. With preheating wire by resistance heat, laser hot wire cladding shows better process stability and higher deposition efficiency compared to laser cold wire/powder cladding. Multi-pass layer were cladded on the surface of martensite precipitation hardening stainless steel FV520B by fiber laser with ER410NiMo wire. Wire feed rate and preheat current were optimized to obtain stable wire transfer, which guaranteed good formation quality of single pass cladding. Response surface methodology (RSM) was used to optimize processing parameters and predict formation quality of multi-pass cladding. Laser power P, scanning speed Vs, wire feed rate Vf and overlap ratio ? were selected as the input variables, while flatness ratio, dilution and incomplete fusion value as the responses. Optimal clad layer with flat surface, low dilution and no incomplete fusion was obtained by appropriately reducing Vf, and increasing P, Vs and ?. No defect like pore or crack was found. The tensile strength and impact toughness of the clad layer is respectively 96% and 86% of those of the substrate. The clad layer showed nonuniform microstructure and was divided into quenched areas with coarse lath martensite and tempered areas with tempered martensite due to different thermal cycles in adjacent areas. The tempered areas showed similar hardness to the substrate.

Wen, Peng; Feng, Zhenhua; Zheng, Shiqing

2015-01-01

217

Irradiation hardening of ODS ferritic steels under helium implantation and heavy-ion irradiation  

NASA Astrophysics Data System (ADS)

Irradiation hardening of ODS ferritic steels after multi-energy He-ion implantation, or after irradiation with energetic heavy ions including Xe and Bi-ions was investigated with nano-indentation technique. Three kinds of high-Cr ODS ferritic steels including the commercial MA956 (19Cr-3.5Al), the 16Cr-0.1Ti and the 16Cr-3.5Al-0.1Zr were used. Data of nano-hardness were analyzed with an approach based on Nix-Gao model. The depth profiles of nano-hardness can be understood by the indentation size effect (ISE) in specimens of MA956 implanted with multi-energy He-ions or irradiated with 328 MeV Xe ions, which produced a plateau damage profile in the near-surface region. However, the damage gradient overlaps the ISE in the specimens irradiated with 9.45 Bi ions. The dose dependence of the nano-hardness shows a rapid increase at low doses and a slowdown at higher doses. An 1/2-power law dependence on dpa level is obtained. The discrepancy in nano-hardness between the helium implantation and Xe-ion irradiation can be understood by using the average damage level instead of the peak dpa level. Helium-implantation to a high dose (7400 appm/0.5 dpa) causes an additional hardening, which is possibly attributed to the impediment of motion dislocations by helium bubbles formed in high concentration in specimens.

Zhang, Hengqing; Zhang, Chonghong; Yang, Yitao; Meng, Yancheng; Jang, Jinsung; Kimura, Akihiko

2014-12-01

218

Effect of Hf on structure and age hardening of Ti–Al-N thin films  

PubMed Central

Protective coatings for high temperature applications, as present e.g. during cutting and milling operations, require excellent mechanical and thermal properties during work load. The Ti1 ? xAlxN system is industrially well acknowledged as it covers some of these requirements, and even exhibits increasing hardness with increasing temperature in its cubic modification, known as age hardening. The thermally activated diffusion at high temperatures however enables for the formation of wurtzite AlN, which causes a rapid reduction of mechanical properties in Ti1 ? xAlxN coatings. The present work investigates the possibility to increase the formation temperature of w-AlN due to Hf alloying up to 10 at.% at the metal sublattice of Ti1 ? xAlxN films. Ab initio predictions on the phase stability and decomposition products of quaternary Ti1 ? x ? yAlxHfyN alloys, as well as the ternary Ti1 ? xAlxN, Hf1 ? xAlxN and Ti1 ? zHfzN systems, facilitate the interpretation of the experimental findings. Vacuum annealing treatments from 600 to 1100 °C indicate that the isostructural decomposition, which is responsible for age hardening, of the Ti1 ? x ? yAlxHfyN films starts at lower temperatures than the ternary Ti1 ? xAlxN coating. However, the formation of a dual phase structure of c-Ti1 ? zHfzN (with z = y/(1 ? x)) and w-AlN is shifted to ~ 200 °C higher temperatures, thus retaining a film hardness of ~ 40 GPa up to ~ 1100 °C, while the Hf free films reach the respective hardness maximum of ~ 38 GPa already at ~ 900 °C. Additional annealing experiments at 850 and 950 °C for 20 h indicate a substantial improvement of the oxidation resistance with increasing amount of Hf in Ti1 ? x ? yAlxHfyN. PMID:22319223

Rachbauer, R.; Blutmager, A.; Holec, D.; Mayrhofer, P.H.

2012-01-01

219

Macromolecules from cold-adapted antarctic fishes  

Microsoft Academic Search

The article reviews the studies of the authors and other investigators on blood proteins and muscle and brain enzymes from Antarctic fishes adapted to the -1.85 °C temperature of the ice-salt water of McMurdo Sound, Antarctica. The bloods had two major characteristics related to the cold-adaptation: a rapid rate of clotting of the blood at 0 °C and a very

R. E. Feeney; J. Vandenheede; D. T. Osuga

1972-01-01

220

The Common Cold  

NSDL National Science Digital Library

When winter rolls around and we begin to spend more time indoors, the common cold becomes an unfortunate reality for many of us. But for something as common as the cold, misconceptions about it are remarkably common as well. The following collection of Web sites provides an in-depth look at the cold and the cold virus.The first site (1) comes from the Common Cold Care Center of Cardiff University in Wales, and offers a thorough and highly readable introduction to the common cold, including sections on conventional and alternative cold medications. Readers can brush up on their basic virology with the next Web site from HowStuffWorks to get a clear, general idea of how the cold virus infects the body (2). This site also explains why antibiotics have no effect on a virus, and includes numerous hypertext links to related HowStuffWorks Web pages. KidsHealth for Parents, a service of the Nemours Foundation, provides a straightforward guide to the symptoms of cold vs. flu, while also offering information on flu treatment options (3). The next Web site, from University of Guelph, contains an easy-to-understand comparison of bacteria and viruses (4). Readers can learn more about rhinoviruses, the family of viruses which account for about one-third of all colds, in the following Web site from the University of South Carolina's Microbiology and Immunology Online (5). The next Web site offers visitors a close-up look at human rhinovirus 14 with over a dozen 3-D images and movies from the University of Wisconsin-Madison Bock Laboratory (6). The following site describes the findings, as detailed in the Proceedings of the National Academy of Sciences, of a Purdue University research team that has analyzed on an atomic scale the structure of the cellular receptor that binds cold-causing viruses (7). And finally, find out about common cold clinical trials with ClinicalTrial.gov, a service of the National Institutes of Health (8).

Sohmer, Rachel.

2003-01-01

221

Coping with Colds  

MedlinePLUS

... by viruses called rhinoviruses that are in invisible droplets in the air you breathe or on things ... Continue Catching Colds Rhinoviruses can stay alive as droplets in the air or on surfaces for as ...

222

Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash  

DOEpatents

The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points.

Liskowitz, John W. (Belle Mead, NJ); Wecharatana, Methi (Parsippany, NJ); Jaturapitakkul, Chai (Bangkok, TH); Cerkanowicz, deceased, Anthony E. (late of Livingston, NJ)

1997-01-01

223

Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash  

DOEpatents

The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points. 2 figs.

Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

1997-10-28

224

Fatigue resistance of titanium alloy VT3-1 connection with surface work-hardening  

SciTech Connect

The authors describe how surface work-hardening increases the endurance limit of smooth specimens of titanium alloy VT3-1 cut from bars by 25-30%. The range of the efficiency of strain-hardening by vibrational treatment and burnishing is 3-7%, the exact percentage depending on processing factors in each form of work-hardening. Work-hardening reduces scatter of fatigue characteristics, which enhances the effectiveness of the resulting strain-hardening with a decrease in the probability of fracture. Surface strain-hardening is recommended for alloy VT3-1, since it increases resistance to fatigue and reduces scatter of fatigue characteristics used in design.

Stepnov, M.N.; Agamirov, L.V.; Giatsintov, E.V.; Gus'kova, L.N.; Veitsman, M.G.

1985-11-01

225

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

Designed to help teachers deal with students in a cold environment, this article explains cold physiology and fundamental laws of heat; describes 14 common cold injuries and their current treatment; and lists a number of useful teaching techniques for cold environments. (SB)

Ewert, Alan

1979-01-01

226

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

Instructors who teach outdoors in an environment so cold as to cause injury must satisfy program objectives while avoiding cold injury to themselves and students, help students focus on learning instead of discomfort, and alleviate some students' intense fear of the cold. Dealing with the cold successfully requires a thorough knowledge of:…

Ewert, Alan

227

An analysis of grain boundary cohesion in precipitation hardened stainless steel  

Microsoft Academic Search

17-4 precipitation hardened (PH) stainless steel belongs to the family of precipitation hardening martensitic stainless steel (AISI 630), containing 17%Cr, 4%Ni and 4%Cu as the main alloying elements; carbon content in the steel is normally maintained below about 0.05 wt.%. The authors have recently attempted an assessment of 17-4 precipitation hardened martensitic steel in terms of processing steps and heat

R. D. K Misra; R. Rao

1993-01-01

228

Alternating current potential-drop measurement of the depth of case hardening in steel rods  

Microsoft Academic Search

The case depth of induction-hardened steel rods has been determined using multi-frequency alternating current potential-drop measurements. Experimental results are analyzed using a model which approximates the variation in the material properties of a hardened rod by assuming that a homogeneous core is surrounded by a homogeneous case-hardened layer of uniform thickness. Experimental measurements on an untreated rod are used to

John R. Bowler; Yongqiang Huang; Haiyan Sun; Jonathan Brown; Nicola Bowler

2008-01-01

229

Case depth verification of hardened samples with Barkhausen noise sweeps  

SciTech Connect

An interesting topic of recent Barkhausen noise (BN) method studies is the application of the method to case depth evaluation of hardened components. The utilization of BN method for this purpose is based on the difference in the magnetic properties between the hardened case and the soft core. Thus, the detection of case depth with BN can be achieved. The measurements typically have been carried out by using low magnetizing frequencies which have deeper penetration to the ferromagnetic samples than the conventional BN measurement. However, the penetration depth is limited due to eddy current damping of the signal. We introduce here a newly found sweep measurement concept for the case depth evaluation. In this study sweep measurements were carried out with various magnetizing frequencies and magnetizing voltages to detect the effect of different frequency and voltage and their correspondence to the actual case depth values verified from destructive characterization. Also a BN measurement device that has an implemented sweep analysis option was utilised. The samples were either induction or case-hardened samples and sample geometry contained both rod samples and gear axle samples with different case depth values. Samples were also further characterized with Xray diffraction to study the residual stress state of the surface. The detailed data processing revealed that also other calculated features than the maximum slope division of the 1st derivative of the BN signal could hold the information about the case depth value of the samples. The sweep method was able to arrange the axles into correct order according to the case depth value even though the axles were used.

Santa-aho, Suvi; Vippola, Minnamari; Lepistö, Toivo [Tampere University of Technology, Department of Materials Science, P.O. Box 589, 33101 Tampere (Finland); Hakanen, Merja [Stresstech Oy, Tikkutehtaantie 1, 40800 Vaajakoski (Finland); Sorsa, Aki; Leiviskä, Kauko [University of Oulu, Control Engineering Laboratory, P.O. Box 4300, FIN-90014 University of Oulu (Finland)

2014-02-18

230

Critical role of zinc in hardening of Nereis jaws  

PubMed Central

Summary Hardening of invertebrate jaws and mandibles has been previously correlated to diverse, potentially complex modifications. Here we demonstrate directly, for the first time, that Zn plays a critical role in the mechanical properties of histidine-rich Nereis jaws. Using nanoindentation, we show that removal of Zn by chelation decreases both hardness and modulus by over 65%. Moreover, reconstitution of Zn yields a substantial recovery of initial properties. Modulus and hardness of Zn-replete jaws exceed those attainable by current engineering polymers by a factor of >3. Zn-mediated histidine cross-links are proposed to account for this enhancement in mechanical properties. PMID:16888069

Broomell, Chris C.; Mattoni, Mike A.; Zok, Frank W.; Waite, J. Herbert

2007-01-01

231

Active radiation hardening technology for fiber-optic source  

NASA Astrophysics Data System (ADS)

We demonstrated an active radiation hardening technology for fiber optic source developed for high performance fiber optic gyroscope. The radiation characteristic of erbium-doped fiber was studied experimentally. The radiation induced attenuation (RIA) at 980nm pump light was identified to be the main reason for the degradation and there was photo-bleaching effect in EDF too. A variable parameters control technology was proposed and taken to keep the 980nm and 1550nm light energy stable and high stability and radiation-resistance fiber source with gauss profile spectrum was realized .The source can stand against more than 50 krad (Si) total radiation dose.

Yang, Yuanhong; Suo, Xinxin; Yang, Mingwei

2013-09-01

232

Hardening communication ports for survival in electrical overstress environments  

NASA Technical Reports Server (NTRS)

Greater attention is being focused on the protection of data I/O ports since both experience and lab tests have shown that components at these locations are extremely vulnerable to electrical overstress (EOS) in the form of transient voltages. Lightning and electrostatic discharge (ESD) are the major contributors to these failures; however, these losses can be prevented. Hardening against transient voltages at both the board level and system level has a proven record of improving reliability by orders of magnitude. The EOS threats, typical failure modes, and transient voltage mitigation techniques are reviewed. Case histories are also reviewed.

Clark, O. Melville

1991-01-01

233

Measurement of Water Transport from Saturated Pumice Aggregates to Hardening Cement Paste  

E-print Network

Measurement of Water Transport from Saturated Pumice Aggregates to Hardening Cement Paste by Pietro-ray absorption showed that considerable transport of water from saturated lightweight aggregates (pumice

Bentz, Dale P.

234

Hardening mechanisms in a dynamic strain aging alloy, Hastelloy X, during isothermal and thermomechanical cyclic deformation  

NASA Technical Reports Server (NTRS)

The relative contributions of the hardening mechanisms in Hastelloy X during cyclic deformation were investigated by conducting isothermal cyclic deformation tests within a total strain range of +/-0.3 pct and at several temperatures and strain rates, and thermomechanical tests within several different temperature limits. The results of the TEM examinations and special constant structure tests showed that the precipitation on dislocations of Cr23C6 contributed to hardening, but only after sufficient time above 500 C. Solute drag alone produced very considerable cyclic hardening. Heat dislocation densities, peaking around 10 exp 11 per sq cm, were found to develop at temperatures producing the greatest cyclic hardening.

Miner, R. V.; Castelli, M. G.

1992-01-01

235

Anisotropy of Dynamic Compressive Properties of Non-Heat-Treating Cold-Heading-Quality Steel Bars  

NASA Astrophysics Data System (ADS)

In the current study, a non-heat-treating cold-heading-quality steel bar was fabricated by cold drawing of a rolled bar, and anisotropic mechanical properties of the as-rolled and cold-drawn bars were investigated by quasistatic and dynamic compressive tests of 0 deg (longitudinal)-, 45 deg-, and 90 deg (transverse)-orientation specimens. Under the dynamic compressive loading, the trend of strength variation was similar to that of the quasistatic compressive loading, while the strength level was considerably increased by the strain rate hardening effect. Stress-strain curves of the cold-drawn bar specimens showed the nearly same strain hardening behavior, irrespective of specimen orientation and strain rate, but the yield stress and compressive flow stress increased in the order of the 0 deg-, 90 deg-, and 45 deg-orientation specimens. In the 45 deg- and 90 deg-orientation specimens, the pearlite bands had the stronger resistance to the stress acting on the maximum shear stress plane than in the 0 deg-orientation specimens, thereby resulting in the higher strengths. In some dynamically compressed specimens, pearlite bands were dissolved to form bainitic microstructures. Locations of these bainitic microstructures were well matched with hemispherical-shaped heat-trap zones, which confirmed that bainitic microstructures were formed by the temperature rise occurring during the dynamic compressive loading.

Kim, Hyunmin; Kang, Minju; Bae, Chul Min; Kim, Hyoung Seop; Lee, Sunghak

2014-01-01

236

Folding and faulting of strain-hardening sedimentary rocks  

USGS Publications Warehouse

The question of whether single- or multi-layers of sedimentary rocks will fault or fold when subjected to layer-parallel shortening is investigated by means of the theory of elastic-plastic, strain-hardening materials, which should closely describe the properties of sedimentary rocks at high levels in the Earth's crust. The most attractive feature of the theory is that folding and faulting, intimately related in nature, are different responses of the same idealized material to different conditions. When single-layers of sedimentary rock behave much as strain-hardening materials they are unlikely to fold, rather they tend to fault, because contrasts in elasticity and strength properties of sedimentary rocks are low. Amplifications of folds in such materials are negligible whether contacts between layer and media are bonded or free to slip for single layers of dolomite, limestone, sandstone, or siltstone in media of shale. Multilayers of these same rocks fault rather than fold if contacts are bonded, but they fold readily if contacts between layers are frictionless, or have low yield strengths, for example due to high pore-water pressure. Faults may accompany the folds, occurring where compression is increased in cores of folds. Where there is predominant reverse faulting in sedimentary sequences, there probably were few structural units. ?? 1980.

Johnson, A.M.

1980-01-01

237

DISCREPANT HARDENING OBSERVED IN COSMIC-RAY ELEMENTAL SPECTRA  

SciTech Connect

The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of {approx}70 days, which indicate hardening of the elemental spectra above {approx}200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at {approx}10{sup 15} eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Lutz, L.; Malinin, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P.; Beatty, J. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Siena 53100 (Italy); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, MN 55414 (United States); Conklin, N. B.; Coutu, S.; Mognet, S. I. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A. [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Minnick, S. [Department of Physics, Kent State University Tuscarawas, New Philadelphia, OH 44663 (United States)], E-mail: seo@umd.edu (and others)

2010-05-01

238

Electromagnetic induction heating for cold wall rapid thermal processing  

Microsoft Academic Search

Electromagnetic Induction Heating is a novel heating technique by which shallow implanted dopants can be activated with minimal movement of the as implanted profile. Silicon wafers can be directly heated, without the use of a susceptor, in the RF (13.56 MHz), microwave (2.45 GHz), or millimeter wave (30.5 GHz) regimes. Heating rates of at least 125°C\\/sec have been achieved and

K. Thompson; J. H. Booske; Y. Gianchandani; R. Cooper; Yu. Bykov; A. Eremeev; I. Plotnikov

2001-01-01

239

Rapid Prototyping  

NASA Technical Reports Server (NTRS)

Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

1999-01-01

240

Modelling of strain hardening and microstructural evolution in equal channel angular extrusion  

Microsoft Academic Search

Strain hardening as well as crystallographic texture development is studied in polycrystalline OFHC Cu subjected to equal channel angular extrusion (ECAE) up to four passes. The experiments have been carried out at room temperature in a 90° die, following Route A processing. Texture development was followed using pole figures and hardening was measured by Vickers hardness testing. The self-consistent viscoplastic

László S. Tóth

2005-01-01

241

The effects of x-ray beam hardening on detective quantum efficiency and radiation dose  

PubMed Central

The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The DQE and the average glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results demonstrate a reduction of 15% to 24% for the range of beam hardening levels. The comparison of all quantities comprising the DQE exhibit very close correlation between the results obtained without added beam hardening to the results corresponding to the range of beam hardening levels. For the specific experimental conditions utilized in this preliminary study, the results are an indication that the use of beam hardening holds the potential to reduce the radiation dose without decreasing the performance of the system. Future studies will seek to apply this method in a clinical environment and perform a comprehensive image quality evaluation, in an effort to further evaluate the potential of beam hardening to balance the tradeoff between dose and image quality. PMID:25214383

Wong, Molly Donovan; Wu, Xizeng; Liu, Hong

2011-01-01

242

Thermal and Thermal-Stressed States of Railway Wheels in the Process of Local Surface Hardening  

Microsoft Academic Search

We study the thermal and thermal-stressed states of the tires of railway wheels in the process of local surface hardening. For different points of the cross section of a tire, we determine the time dependences of temperature, thermal stresses, strains, strain rates, and the ratios of principal stresses. It is shown that, in the process of hardening, the material is

B. S. Karpinos; V. G. Barilo; S. V. Petrov; A. G. Saakov; L. I. Markashova; M. I. Valevich; V. P. Drogovoz; N. G. Solov'eva; V. V. Zadorozhnyi

2004-01-01

243

PRECIPITATION HARDENING IN ALUMINUM ALLOY 6022 W.F. Miao and D.E. Laughlin  

E-print Network

PRECIPITATION HARDENING IN ALUMINUM ALLOY 6022 W.F. Miao and D.E. Laughlin Department of Materials on a precipitation hardening process. The precipitation sequence in the Al-Mg-Si alloys is generally accepted [1-shaped precipitates (circular cross sections) along 100 Al, having a hexagonal crystal structure with a 0.705 nm and c

Laughlin, David E.

244

Investigation into springback characteristics of two HSS sheets during cold v-bending  

SciTech Connect

Considering the safety and the light-weight structure, there is an increasing requirement of high strength steel (HSS) sheets in the automotive industry. The high-precise prediction of the springback depends on constitutive equations and their corresponding material parameters. In order to investigate the springback of HSS sheets, DP590 and B280VK, their constitutive behaviors were analyzed based on the sheet tension tests. With respect to the constitutive equation, the Voce model is more proper to two hot-rolled steels, DP590 and B280VK, than the Swift model. Two steels are all saturated hardening, and the degree of hardening decreases with the strain. The cold v-banding tests of two HSS sheets were carried out for evaluation of springback characteristics. Results of v-bending experiments showed that the springback angle increases with the bending along 45°, 90° and 0° to the rolling direction of steel in turn.

Fang, Gang; Gao, Wei-Ran [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

2013-12-16

245

5 Ultra Cold Neutrons  

Microsoft Academic Search

At the Paul Scherrer Institut (PSI) a new source of ultra cold neutrons (UCN) will be con- structed with the goal to improve the sensitivity to the neutron electric dipole moment (nEDM), which is sensitive to possible contributions from new physics. In addition the neu- tron decay parameters such as its life time may be studied more accurately. Presently, we

P. Fierlinger; S. Heule; U. Straumann

246

Cold Facts about Viruses.  

ERIC Educational Resources Information Center

Provides ways for students to demonstrate their understanding of scientific concepts and skills. Describes a mini-unit around the cold in which students can relate humans to viruses. Includes activities and a modified simulation that provides questions to guide students. Discusses ways that allows students to apply prior knowledge, take ownership…

Pea, Celeste; Sterling, Donna R.

2002-01-01

247

Teaching "In Cold Blood."  

ERIC Educational Resources Information Center

The Truman Capote nonfiction novel, "In Cold Blood," which reflects for adolescents the immediacy of the real world, illuminates (1) social issues--capital punishment, environmental influence, and the gap between the "haves" and "have-nots," (2) moral issues--the complexity of man's nature, the responsibility of one man for another, and the place…

Berbrich, Joan D.

1967-01-01

248

Galactic Cold Cores  

NASA Astrophysics Data System (ADS)

The aims of the project "Cold Cores" include the compilation of an extensive catalog of dense and cold interstellar dust clouds and the characterization of this source population at large scale in the Galaxy. The sources, which range from pre-stellar cores to already star-forming clouds, are being identified from the Planck satellite all-sky survey. With good coverage of sub-millimeter wavelengths, high sensitivity, and a spatial resolution comparable to that of IRAS satellite, Planck is ideal for this search. Herschel will be used for a more detailed study of some 150 Planck-detected target fields. The Herschel data, combined with ground based follow-up observations, are used to determine the evolutionary stages of the detected sources and to study their physical characteristics and dust properties. The Herschel results help us to better understand the initial phases of star formation and give a key to the statistical interpretation of the much larger sample of sources included in the Planck catalog. We describe the scientific goals of the project and show first results from Herschel Science Demonstration Phase observations. In the fields studied so far, observations have revealed isolated starless cores, cores with embedded sources, and cold dust clumps within regions of active star formation. Thus, the results already demonstrate the large variety of Galactic sources harboring cold dust.

Juvela, Mika; Ristorcelli, Isabelle

249

Expert Cold Structure Development  

NASA Astrophysics Data System (ADS)

The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub- orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011.

Atkins, T.; Demuysère, P.

2011-08-01

250

COLD NEUTRON SOURCES  

Microsoft Academic Search

Experimental work on cold neutron source development is reviewed along ; with the theoretical explanations devised for the results obtained. Factors ; governing source design, the associated cryogenic and safety problems, large ; source design, and experiments by which source efficiency might be increased are ; also discussed. (D.C.W.);

F WEBB

1963-01-01

251

Titanium Cold Spray Coatings  

NASA Astrophysics Data System (ADS)

Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical properties similar to a traditional bulk material. Vickers hardness testing and nanoindentation were used as micro-and nano-scale measurement techniques to characterize the mechanical properties of titanium coatings, deposited at different deposition conditions, and bulk Ti. The mechanical properties of bulk titanium and titanium coatings were measured over a range of length scales, with the indentation size effect examined with Meyer's law. Hardness measurements are shown to be affected by material porosity, microstructure and coating particle bonding mechanism. Hard-ness measurements showed that Ti coatings deposited at higher gas pressures and temperatures demonstrate an indentation load response similar to bulk Ti. Key words: titanium, cold spray, Vickers hardness, nanoindentation, indentation size effect, microstructure, mechanical properties

Ajaja, Jihane; Goldbaum, Dina; Chromik, Richard; Yue, Stephen; Rezaeian, Ahmad; Wong, Wilson; Irissou, Eric; Legoux, Jean-Gabriel

252

A finite strain isotropic/kinematic hardening model for springback simulation of sheet metals  

SciTech Connect

Crucial for the accurate prediction of the blank springback is the use of an appropriate material model, which is capable of modelling the typical cyclic hardening behaviour of metals (e.g. Bauschinger effect, ratchetting). The proposed material model combines both nonlinear isotropic hardening and nonlinear kinematic hardening, and is defined in the finite strain regime. The kinematic hardening component represents a continuum extension of the classsical rheological model of Armstrong-Frederick kinematic hardening. The evolution equations of the model are integrated by a new form of the exponential map algorithm, which preserves the plastic volume and the symmetry of the internal variables. Finally, the applicability of the model for springback prediction has been demonstrated by performing simulations of the draw-bending process.

Vladimirov, Ivaylo N.; Reese, Stefanie [Institute of Solid Mechanics, Braunschweig University of Technology, D-38106 Braunschweig (Germany)

2007-04-07

253

Testing and Analysis of Full-Scale Creep-Rupture Experiments on Inconel Alloy 740 Cold-Formed Tubing  

NASA Astrophysics Data System (ADS)

Full-scale pressurized creep-rupture tests were conducted on Inconel® alloy 740 cold-formed tube bends to evaluate the effect of cold-work on the performance of tube bends for high-temperature creep applications. A new method of analysis is developed that can be used to simplify the complexities of structural (geometric) effects and material degradation due to cold-work. Results show that Inconel® alloy 740 behaves similarly to other age-hardenable nickel-based alloys subjected to cold-work prior to creep testing with large reductions in rupture life and ductility and a corresponding moderate increase in minimum creep rate. The results also demonstrate that the full-size test method can be a beneficial to understanding the performance of large components in service.

Shingledecker, J. P.; Pharr, G. M.

2013-02-01

254

Hardening effect on machined surface for precise hard cutting process with consideration of tool wear  

NASA Astrophysics Data System (ADS)

During hard cutting process there is severe thermodynamic coupling effect between cutting tool and workpiece, which causes quenching effect on finished surfaces under certain conditions. However, material phase transformation mechanism of heat treatment in cutting process is different from the one in traditional process, which leads to changes of the formation mechanism of damaged layer on machined workpiece surface. This paper researches on the generation mechanism of damaged layer on machined surface in the process of PCBN tool hard cutting hardened steel Cr12MoV. Rules of temperature change on machined surface and subsurface are got by means of finite element simulation. In phase transformation temperature experiments rapid transformation instrument is employed, and the effect of quenching under cutting conditions on generation of damaged layer is revealed. Based on that, the phase transformation points of temperature under cutting conditions are determined. By experiment, the effects of cutting speed and tool wear on white layer thickness in damaged layer are revealed. The temperature distribution law of third deformation zone is got by establishing the numerical prediction model, and thickness of white layer in damaged layer is predicted, taking the tool wear effect into consideration. The experimental results show that the model prediction is accurate, and the establishment of prediction model provides a reference for wise selection of parameters in precise hard cutting process. For the machining process with high demanding on surface integrity, the generation of damaged layer on machined surface can be controlled precisely by using the prediction model.

Yue, Caixu; Liu, Xianli; Ma, Jing; Liu, Zhaojing; Liu, Fei; Yang, Yongheng

2014-11-01

255

Development of a Press-Hardened Steel Suitable for Thin Slab Direct Rolling Processing  

NASA Astrophysics Data System (ADS)

The thin slab casting and direct rolling process is a hot-rolled strip production method which has maintained commercial quality steel grades as a major material in many industrial applications due to its low processing cost. Few innovative products have however been developed specifically for production by thin slab direct rolling. Press hardening or hot press forming steel grades which are now widely used to produce structural automotive steel parts requiring ultra-high strength and formability may however offer an opportunity for thin slab direct rolling-specific ultra-high strength products. In this work, a newly designed press hardening steel grade developed specifically for thin slab direct rolling processing is presented. The press hardening steel has a high nitrogen content compared with press hardening steel grades produced by conventional steelmaking routes. Boron and titanium which are key alloying additions in conventional press hardening steel such as the 22MnB5 press hardening steel grade are not utilized. Cr is added in the press hardening steel to obtain the required hardenability. The properties of the new thin slab direct rolling-specific 22MnCrN5 press hardening steel grade are reviewed. The evolution of the microstructure and mechanical properties with increasing amounts of Cr additions from 0.6 to 1.4 wt pct and the effect of the cooling rate during die-quenching were studied by means of laboratory simulations. The selection of the optimum chemical composition range for the thin slab direct rolling-specific 22MnCrN5 steel in press hardening heat treatment conditions is discussed.

Lee, Jewoong; De Cooman, Bruno C.

2015-01-01

256

Thermal creep model for CWSR zircaloy-4 cladding taking into account the annealing of the irradiation hardening  

SciTech Connect

After irradiation and cooling in a pool, spent nuclear fuel assemblies are either transported for wet storage to a devoted site or loaded in casks for dry storage. During dry transportation or at the beginning of dry storage, the cladding is expected to be submitted to creep deformation under the hoop stress induced by the internal pressure of the fuel rod. The thermal creep is a potential mechanism that might lead to cladding failure. A new creep model was developed, based on a database of creep tests on as-received and irradiated cold-worked stress-relieved Zircaloy-4 cladding in a wide range of temperatures (310 degrees C to 470 degrees C) and hoop stress (80 to 260 MPa). Based on three laws-a flow law, a strain-hardening recovery law, and an annealing of irradiation hardening law this model allows the simulation of not only the transient creep and the steady-state creep, but also the early creep acceleration observed on irradiated samples tested in severe conditions, which was not taken into account in the previous models. The extrapolation of the creep model in the conditions of very long-term creep tests is reassuring, proving the robustness of the chosen formalism. The creep model has been assessed in progressively decreasing stress conditions, more representative of a transport. Set up to predict the cladding creep behavior under variable temperature and stress conditions, this model can easily be implemented into codes in order to simulate the thermomechanical behavior of spent fuel rods in various scenarios of postirradiation phases. (authors)

Cappelaere, Chantal; Limon, Roger; Duguay, Chrstelle; Pinte, Gerard; Le Breton, Michel [CEA Saclay, DEN, Serv Etud Mat Irradies, F-91191 Gif Sur Yvette, (France); Bouffioux, Pol [EDF R et D Renardieres, F-77818 Ecuelles, Moret Sur Loing, (France); Chabretou, Valerie [AREVA NP SAS, AREVA, F-69456 Lyon 6, (France); Miquet, Alain [EDF SEPTEN, F-69628 Villeurbanne, (France)

2012-02-15

257

Thermoregulatory modeling for cold stress.  

PubMed

Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview. PMID:24944030

Xu, Xiaojiang; Tikuisis, Peter

2014-07-01

258

Method of forming a hardened surface on a substrate  

DOEpatents

The invention includes a method of producing a hard metallic material by forming a mixture containing at least 55% iron and at least one of B, C, Si and P. The mixture is formed into an alloy and cooled to form a metallic material having a hardness of greater than about 9.2 GPa. The invention includes a method of forming a wire by combining a metal strip and a powder. The metal strip and the powder are rolled to form a wire containing at least 55% iron and from two to seven additional elements including at least one of C, Si and B. The invention also includes a method of forming a hardened surface on a substrate by processing a solid mass to form a powder, applying the powder to a surface to form a layer containing metallic glass, and converting the glass to a crystalline material having a nanocrystalline grain size.

Branagan, Daniel J. (Iona, ID)

2010-08-31

259

Theoretical Study of the Oxidation Behavior of Precipitation Hardening Steel  

SciTech Connect

The oxidation of precipitation hardening (PH) steels is a rather unexplored area. In the present work an attempt is made is made to estimate the kinetics of a PH steel. For this purpose specimens of the material under examination were isothermally heated at 850, 900 and 950 deg. C for 15 hr. Kinetics was based on TGA results. During heating a thick scale is formed on the substrate surface, which is composed by different oxides. The layer close to the substrate is compact and as a result it impedes corrosion. The mathematical analysis of the collected data shows that the change of the mass of the substrate per unit area versus time is described by a parabolic law.

Pistofidis, N.; Vourlias, G.; Chrissafis, K. [Department of Physics, Aristotle University of Thessaloniki, 541 24 Thessaloniki (Greece); Psyllaki, P. [Department of Mechanical Engineering, Technological Education Institute of Piraeus (TEI), 122 44 Egaleo (Greece); Institute of Materials Science, N.C.S.R. 'Demokritos', 153 10 Aghia Paraskevi, Attiki (Greece)

2010-01-21

260

Strain Hardening Behavior of Dual-Phase Steels  

NASA Astrophysics Data System (ADS)

A detailed qualitative and quantitative examination of the microstructure and mechanical properties of three different classes of DP600 and DP450 dual-phase (DP) steels was carried out. The tested DP steels are characterized by different alloying elements: aluminum, boron, and phosphorus. Among them, aluminum DP steels showed the lowest percentages of hard phases, while phosphorus DP steels exhibited the highest resistance values. The Hollomon, Pickering, Crussard-Jaoul (CJ), and Bergstrom models were used to reproduce the strain hardening behavior of DP steels. Relationships that correlate the fitting parameters with the chemical composition and the thermal cycle parameters were found, and the predictive abilities of different models were evaluated. The Pickering equation, among the tested models, is the best one in the reproduction of the experimental stress-strain data.

Colla, V.; de Sanctis, M.; Dimatteo, A.; Lovicu, G.; Solina, A.; Valentini, R.

2009-11-01

261

Silicon diode radiation hardening for high energy physics detectors  

NASA Astrophysics Data System (ADS)

We summarize in a general review all the studies performed by our group in the last years in the field of radiation hardening of silicon detectors for High Energy Physics experiments. Test structures (silicon p-i-n diodes) were irradiated by 16 MeV, 27 MeV, 34 MeV and 24 GeV protons, and by fast neutrons from a nuclear reactor and from the 9Be(d,n) 10B nuclear reaction. We will show that after proton irradiation the substrate oxygenation mitigates the depletion voltage increase rate ?, which nevertheless presents a wide range of values if standard and oxygenated devices processed by different manufacturers are considered, pointing out that besides oxygenation, processing affects the diode radiation hardness in the case of proton irradiation. After neutron irradiation though the oxygen mitigating effect is strongly suppressed, nonetheless the ? dependence on the particular process can be important.

Rando, R.; Candelori, A.; Bisello, D.; Kaminski, A.; Litovchenko, A.; Pantano, D.; Stavitski, I.; Wyss, J.

2003-11-01

262

Designing Security-Hardened Microkernels For Field Devices  

NASA Astrophysics Data System (ADS)

Distributed control systems (DCSs) play an essential role in the operation of critical infrastructures. Perimeter field devices are important DCS components that measure physical process parameters and perform control actions. Modern field devices are vulnerable to cyber attacks due to their increased adoption of commodity technologies and that fact that control networks are no longer isolated. This paper describes an approach for creating security-hardened field devices using operating system microkernels that isolate vital field device operations from untrusted network-accessible applications. The approach, which is influenced by the MILS and Nizza architectures, is implemented in a prototype field device. Whereas, previous microkernel-based implementations have been plagued by poor inter-process communication (IPC) performance, the prototype exhibits an average IPC overhead for protected device calls of 64.59 ?s. The overall performance of field devices is influenced by several factors; nevertheless, the observed IPC overhead is low enough to encourage the continued development of the prototype.

Hieb, Jeffrey; Graham, James

263

Characterization and hardening of concrete with ultrasonic testing.  

PubMed

In this study, we describe a technique which can be used to characterize some relevant properties of 26 cylindrical samples (15 x 30 cm2) of concrete. The characterization has been performed, according to Spanish regulations in force, by some destructive and ultrasound-based techniques using frequencies of 40 kHz. Samples were manufactured using different water/cement ratios (w/c), ranging from 0.48 to 0.80, in order to simulate different values of compressive strength at each sample. We have correlated the propagation velocity v of ultrasonic waves through the samples to compressive strength R values. As some other authors remark, there exists an exponential relationship between the two above parameters. We have found that a highly linear relationship is present between R and w/c concentration at the samples. Nevertheless, when the same linear model is adopted to describe the relationship between v and w/c, the value of r decreases significantly. Thus, we have performed a multiple regression analysis which takes into account the impact of different concrete constituents (water, cement, sand, etc.) on ultrasound propagation speed. One of the most relevant practical issues addressed in our study is the estimation of the hardening curve of concrete, which can be used to quantify the viability of applying the proposed method in a real scenario. Subsequently, we also show a detailed analysis of the temporal evolution of v and R through 61 days, beginning at the date where the samples were manufactured. After analyzing both parameters separately, a double reciprocal relationship is deduced. Using the above parameters, we develop an NDE-based model which can be used to estimate hardening time of concrete samples. PMID:15047341

del Río, L M; Jiménez, A; López, F; Rosa, F J; Rufo, M M; Paniagua, J M

2004-04-01

264

[Hardened anodized aluminum as a replacement material for bracket manufacture].  

PubMed

Attention has been repeatedly drawn to the problem of corrosion and the risk of allergic reaction to nickel resulting from the use of stainless steel brackets. In the search for a suitable alternative, manufacturers have turned to thin coating technology using hardened anodized aluminium. Applying resistance to corrosion and abrasion as the criteria to be met, they have selected aluminium alloy type 6082 as the material of choice. Purpose of this study is to examine the physical suitability of this material. Using the above noted alloy, 60 prototype brackets were made with a hardened anodized surface. They were then subjected to the following 3 stress tests: first an abrasion test using a tooth polishing machine, second, a deformation test using a device designed to simulate torque movement, and, third, a corrosion test. The effects on the brackets resulting from the three types of stress were evaluated by light microscopy. A quantitative analysis of the corrosion test was performed by ICP spectrometry. The control group consisted of conventional stainless steel brackets. The light microscopic analysis revealed no evidence of surface damage or signs of deformation in the prototype brackets. The steel brackets, on the other hand, showed clear signs of wear and corrosion. The quantitative analysis of the corrosion solution revealed metallic ion wear of 1.75 ng x mm-2 x h-1 for the prototypes subjected to abrasion. The steel brackets showed at a factor of around 104.6 metallic ion wear of 183 ng x mm-2 x h-1. In addition to this, no Ni ions were found in the corrosion solution of the prototype brackets.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7851828

Fischer-Brandies, H; Bönhoff, M

1994-12-01

265

The analysis on viable development mode of farm produce cold chain logistics industry of Henan Province  

Microsoft Academic Search

The farm produce in Henan Province is featured by abundant output and high level of consumption, hence it is conducive to the development of farm produce cold chain development so as to satisfy the demand of the consumers. The cold chain logistics industry is currently undergoing a rapid growth in Henan Province. However, some problems exist. This paper puts forward

Xin-Ping Ren

2011-01-01

266

Imaging with cold neutrons  

NASA Astrophysics Data System (ADS)

Neutrons for imaging purposes are provided mainly from thermal beam lines at suitable facilities around the world. The access to cold neutrons is presently limited to very few places only. However, many challenging options for imaging with cold neutrons have been found out, given by the interaction behavior of the observed materials with neutrons in the cold energy range (3-10 Å). For absorbing materials, the interaction probability increases proportionally with the wavelength with the consequence of more contrast but less transmission with cold neutrons. Many materials are predominantly scattering neutrons, in particular most of crystalline structural materials. In these cases, cold neutrons play an important role by covering the energy range of the most important Bragg edges given by the lattice planes of the crystallites. This particular behavior can be used for at least two important aspects—choosing the right energy of the initial beam enables to have a material more or less transparent, and a direct macroscopic visualization of the crystalline structure and its change in a manufacturing process. Since 2006, PSI operates its second beam line for neutron imaging, where cold neutrons are provided from a liquid deuterium cold source (operated at 25 K). It has been designed to cover the most current aspects in neutron imaging research with the help of high flexibility. This has been done with changeable inlet apertures, a turbine based velocity selector, two beam positions and variable detector systems, satisfying the demands of the individual investigation. The most important detection system was found to be a micro-tomography system that enables studies in the presently best spatial resolution. In this case, the high contrast from the sample interaction process and the high detection probability for the cold neutrons combines in an ideal combination for the best possible performance. Recently, it was found out that the energy selective studies might become a research field in its own sing the Bragg edge behavior and its modification to contribute to material research by the direct visualization of textures and the observation of stress and strain. This topic is still in the beginning but has some important relevance for the design of future beam lines for imaging at the pulsed spallation sources. Considering the neutrons to be waves, the cold energy range is important to push and to investigate phase effects in detail with high spatial resolution. Although a lot of studies have been done in this respect previously, there is enough space to study refraction at the edges, diffraction and total reflection with the best possible accuracy, and to figure out when and why neutrons interfere. Phase contrast methods like grating interference methods have to be implemented as a user option, which enables one to define their future application range.

Lehmann, E. H.; Kaestner, A.; Josic, L.; Hartmann, S.; Mannes, D.

2011-09-01

267

Small Cold Temperature Instrument Packages  

Microsoft Academic Search

We are developing a small cold temperature instrument package concept that integrates a cold temperature power system with ultra low temperature ultra low power electronics components and power supplies now under development into a ‘cold temperature surface operational’ version of a planetary surface instrument package. We are already in the process of developing a lower power lower temperature version for

P. E. Clark; P. S. Millar; P. S. Yeh; S. Feng; D. Brigham; B. Beaman

2011-01-01

268

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

COLD STORAGE DESIGN AND REFRIGERATION EQUIPMENT REFRIGERATION OF FISH - PART 1 \\ "..\\- ,,, T I Fishery Leaflet 427 Washington 25, D. C. June 1956 REFRIGERATION OF FISH - PART em; COlD STORAGE DESIGN (Section 1), and F. Bruce Sanford (Section 1) Table of Contents Pages Section 1 - Cold Storage Design

269

Progress in the technology and applications of in-situ atmosphere production in hardening and case-hardening furnaces  

SciTech Connect

The utilization of in-situ atmospheres for neutral hardening and gas carburizing is steadily increasing in batch furnaces as well as continuous furnaces. Depending on furnace temperature and type of fuel used for atmosphere production, the furnace atmosphere is closer to or further away from chemical equilibrium. This makes the carbon-potential measurement and control difficult. The theory of controllability of non-equilibrium atmospheres is shortly described. Different fuels possess different properties with respect to carbon transfer, case-structure (internal oxidation) and cycle speed. This is compared to other atmosphere systems like endothermic atmosphere and nitrogen/methanol based systems. The applicational range of different in-situ atmospheres varies. Its utilization in different furnaces is presented together with the achieved energy savings.

Edenhofer, B. [Ipsen Industries International GmbH, Kleve (Germany)

1995-12-31

270

Comparison of three cold hardiness tests for conifer seedlings.  

PubMed

Greenhouse-cultured, container-grown ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and Engelmann spruce (Picea engelmannii (Parry) Engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. Cold hardiness was measured weekly by a whole-plant freeze test and by two quick tissue tests: freeze-induced electrolyte leakage of needles, and differential thermal analysis of buds. The whole-plant freeze test provided results in 7 days, and indicated differences in cold hardiness among stems, buds, and needles. Although the whole-plant freeze test could accurately measure cold hardiness, it was not precise, and it required destructive sampling. Results from freeze-induced electrolyte leakage and differential thermal analysis were available in 2 days and 1 hour, respectively. The freeze-induced electrolyte leakage test was a precise, sensitive and objective predictor of changes or differences in tissue cold hardiness. To determine actual cold hardiness, results could be calibrated to the response of the same tissue in the whole-plant freeze test. The speed and objectivity of differential thermal analysis made this test useful for rapid, general assessment of cold hardiness status, but calibration was difficult, and precision varied. PMID:14972928

Burr, K E; Tinus, R W; Wallner, S J; King, R M

1990-12-01

271

The effects of cold rolling on the microstructural and spall response of 1100 aluminum  

NASA Astrophysics Data System (ADS)

As received 1100-O aluminum was cold rolled (CR) to 30%, 70%, and 80% reduction, respectively, to study the effects of microstructural evolution on the spall response using plate impact experiments. Previous results show a sharp increase in pullback velocity for 1100-O aluminum with increase in peak shock stress between 4.0 and 8.3 GPa due to hardening, followed by a decrease for peak shock stresses up to 12.0 GPa possibly due to softening. This maximum was not observed for the 30% CR, which showed only an increase in pullback velocity over the shock stress range of 4.0-12.0 GPa due to hardening (net increase in dislocation density). For the 70% CR aluminum, no change was observed in the pullback velocity over the range tested (4.0-11.0 GPa) probably due to saturation in dislocation density. Similar observations were made for the 80% CR, that is, no change was observed in the spall response between 4.0 GPa and 11.0 GPa. However, variations were observed in the spall response for the 80% CR, and these variations are attributed to material inhomogeneity possibly caused by increased cold rolling beyond saturation. The results also show a significant increase in Hugoniot Elastic Limit with increase in percent cold rolling.

Williams, C. L.; Chen, C. Q.; Ramesh, K. T.; Dandekar, D. P.

2013-09-01

272

Cold heteromolecular dipolar collisions.  

PubMed

Cold molecules promise to reveal a rich set of novel collision dynamics in the low-energy regime. By combining for the first time the techniques of Stark deceleration, magnetic trapping, and cryogenic buffer gas cooling, we present the first experimental observation of cold collisions between two different species of state-selected neutral polar molecules. This has enabled an absolute measurement of the total trap loss cross sections between OH and ND(3) at a mean collision energy of 3.6 cm(-1) (5 K). Due to the dipolar interaction, the total cross section increases upon application of an external polarizing electric field. Cross sections computed from ab initio potential energy surfaces are in agreement with the measured value at zero external electric field. The theory presented here represents the first such analysis of collisions between a (2)? radical and a closed-shell polyatomic molecule. PMID:21881670

Sawyer, Brian C; Stuhl, Benjamin K; Yeo, Mark; Tscherbul, Timur V; Hummon, Matthew T; Xia, Yong; K?os, Jacek; Patterson, David; Doyle, John M; Ye, Jun

2011-11-14

273

WISPy cold dark matter  

SciTech Connect

Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population until today. We find that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold dark matter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches — exploiting haloscopes (direct dark matter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques — can probe large parts of this parameter space in the foreseeable future.

Arias, Paola; Goodsell, Mark; Ringwald, Andreas [Deutsches Elektronen-Synchrotron, Notkestraße 85, D-22607 Hamburg (Germany); Cadamuro, Davide; Redondo, Javier [Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München (Germany); Jaeckel, Joerg, E-mail: paola.arias@desy.de, E-mail: cadamuro@mppmu.mpg.de, E-mail: mark.goodsell@cern.ch, E-mail: joerg.jaeckel@durham.ac.uk, E-mail: redondo@mppmu.mpg.de, E-mail: andreas.ringwald@desy.de [Institute for Particle Physics Phenomenology, Durham University, Durham DH1 3LE (United Kingdom)

2012-06-01

274

Limitations of heart preservation by cold storage.  

PubMed

Clinical heart preservation is currently limited to only 4-6 hr, while the kidney, liver, and pancreas can tolerate 24-48 hr of cold ischemia. A fundamental difference between these organs is that the heart is contractile, containing large quantities of actin and myosin, and is susceptible to contracture-induced injury caused by energy deprivation. We have quantified and correlated the onset of contracture with levels of ATP and glycogen during cold storage in rabbit hearts flushed with UW solution, with and without 1 mM calcium (Ca), or 3 mM iodoacetate (IAA). A fluid-filled left ventricular balloon was used to generate pressure-volume curves (compliance) at 1, 6, 12, 18, and 24 hr of cold storage. Onset of contracture occurred in UW stored hearts at 18 hr, contracture in hearts exposed to Ca occurred between 6 and 12 hr. Compliance was significantly less in hearts exposed to Ca at 12, 18, and 24 hr (P less than .01) than in hearts without Ca. ATP levels were well maintained for up to 18 hr in the hearts preserved in UW solution (78%), but fell more rapidly in the presence of Ca at 12 hr (P less than .005), 18 hr (P less than .005), and 24 hr (P less than .05). In comparison, the ATP supply of the liver and kidney was exhausted by only 4 hr of cold storage. Onset of myocardial contracture correlated with a decrease in ATP to less than 80% of control, and contracture accelerated ATP decline 3-6-fold. IAA caused nearly complete myocardial contracture and ATP depletion within 2 hr. Isolated heart function was 77% and 73% at 6 and 12 hr of storage, but fell to 54% and 42% at 18 and 24 hr, respectively, coinciding with development of contracture. We conclude that ischemic contracture in this model is a major cause of myocardial damage during cold storage, and is accelerated by the presence of Ca. Other organs can be successfully stored despite exhaustion of ATP reserves. Thus successful cold-storage of the heart is highly ATP-dependent. Since cold storage inevitably leads to ATP depletion, extension of myocardial ischemic tolerance will depend on either reversible inhibition of ATP hydrolysis during storage, reversible uncoupling of contracture development from ATP depletion, or maintaining ATP production by continuous hypothermic perfusion. PMID:1738922

Stringham, J C; Southard, J H; Hegge, J; Triemstra, L; Fields, B L; Belzer, F O

1992-02-01

275

Cold denaturation of encapsulated ubiquitin.  

PubMed

Theoretical considerations suggest that protein cold denaturation can potentially provide a means to explore the cooperative substructure of proteins. Protein cold denaturation is generally predicted to occur well below the freezing point of water. Here NMR spectroscopy of ubiquitin encapsulated in reverse micelles dissolved in low viscosity alkanes is used to follow cold-induced unfolding to temperatures below -25 degrees C. Comparison of cold-induced structural transitions in a variety of reverse micelle-buffer systems indicate that protein-surfactant interactions are negligible and allow the direct observation of the multistate cold-induced unfolding of the protein. PMID:16910639

Pometun, Maxim S; Peterson, Ronald W; Babu, Charles R; Wand, A Joshua

2006-08-23

276

Teachers Debate Cold Fusion  

NASA Astrophysics Data System (ADS)

What follows is a collection of messages about cold fusion from teachers. The messages were posted on the internet discussion list, Phys-L, or were sent to me in private. They illustrate a wide range of opinion. Phys-L is a list dedicated to learning and teaching physics with 700 subscribers from over 35 countries, the majority of whom are physics educators. <>.

Kowalski, Ludwik

2005-12-01

277

Crazy Cold Air  

NSDL National Science Digital Library

In this classroom activity, students record the temperatures in and around a walk-in refrigerator or freezer to see how cold air behaves when it meets warmer air. The printable five-page handout includes a series of inquiry-based questions to get students thinking about how the temperature of air changes its density, detailed experiment directions and a worksheet that helps students use the experiment results to obtain insight into the wind patterns of Antarctica.

278

Clumpy cold dark matter  

NASA Technical Reports Server (NTRS)

A study is conducted of cold dark matter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass dark matter cores in globular clusters and in galactic nuclei. Results from terrestrial dark matter detection experiments may be affected by clumpiness in the Galactic halo.

Silk, Joseph; Stebbins, Albert

1993-01-01

279

Familial Cold Autoinflammatory Syndrome  

PubMed Central

Familial cold autoinflammatory syndrome is an autosomal dominant inherited inflammatory disease characterized by episodes of rash, fever, and joint pain following generalized exposure to cold. Attacks usually occur 1–2 hours after exposure and last less than 24 hours. It has been reported primarily in families from North America and Europe, but sporadic cases have also been reported. The diagnosis is based on clinical presentation and can be confirmed by the identification of a NALP3 mutation. No clinical trials have been performed with FCAS patients, but anakinra, an IL-1 receptor antagonist, has been effective at preventing symptoms prior to a cold challenge and as a maintenance medication in several patients. The NALP3 gene, also known as CIAS1, is expressed in peripheral blood leukocytes and chondrocytes and codes a protein also known as Cryopyrin. NALP3 mutations have also been identified in Muckle Wells syndrome and Chronic infantile neurologic cutanaeous articular syndrome. There are several laboratories in Europe and North America where sequencing of NALP3 is performed. PMID:11590390

Hoffman, Doctor Hal M

2015-01-01

280

Hot flakes in cold cases.  

PubMed

In the past, it was almost impossible for forensic scientists to separate DNA from an undefined number of different individuals in mixed stains where, for example, two or more suspects had handled the same weapon. Such samples often contain complex mixtures with the consequence of ambiguous or inconclusive mixed DNA profiles. Using the method described of comprehensive and/or targeted screening of shed cells adhering to tapings of garments or objects enables such stains to be individualized. To evaluate the method, 500 microscopically selected single skin flakes were analyzed using two different commercial STR kits to compare the success rates for each PCR typing system. The method has been validated for use in routine casework and has been shown to be rapid, sensitive, and reproducible. It can be predicted that many cases in the archives with body tapings, which have not yet been examined will benefit from this new or perhaps more appropriate, reanimated, technical development, and of particular importance are serious crimes, the so-called cold cases. The remarkable forensic value of this simple but time-consuming technique is exemplified by 2 out of approximately 100 cases already successfully solved using this approach. PMID:21258941

Schneider, Harald; Sommerer, Thomas; Rand, Steve; Wiegand, Peter

2011-07-01

281

Structural characterisation of oxygen diffusion hardened alpha-tantalum PVD-coatings on titanium.  

PubMed

Titanium substrates were coated with tantalum layers of 5 ?m thickness using physical vapour deposition (PVD). The tantalum layers showed a (110)-preferred orientation. The coated samples were hardened by oxygen diffusion. Using X-ray diffraction the crystallographic structure of the tantalum coatings was characterised, comparing untreated and diffusion hardened specimen conditions. Oxygen depth profiles were determined by glow discharge spectrometry. The hardening effect of the heat treatment was examined by Vickers microhardness testing. The increase of surface hardness caused by oxygen diffusion was at least 50%. PMID:24907733

Hertl, C; Koll, L; Schmitz, T; Werner, E; Gbureck, U

2014-08-01

282

Fatigue resistance of titanium alloy VT3-1 in connection with surface work-hardening  

Microsoft Academic Search

Conclusions 1.Surface work-hardening increases the endurance limit of smooth specimens of titanium alloy VT3-1 cut from bars by 25\\\\2-30%.The surface work-hardening of specimens cut from large forgings increases the endurance limit by 6–8% for a fracture probability p=50% in the endurance range N=5·105-107 cycles.2.The range of the efficiency of strain-hardening by vibrational treatment and burnishing is 3\\\\2-7%, the exact percentage

M. N. Stepnov; M. G. Veitsman; E. V. Giatsintov; L. V. Agamirov; L. N. Gus'kova

1985-01-01

283

Developments in Radiation-Hardened Electronics Applicable to the Vision for Space Exploration  

NASA Technical Reports Server (NTRS)

The Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the anticipated requirements of NASA's Constellation program. Methods of protecting and hardening electronics against the encountered space environment are discussed. Critical stages of a spaceflight mission that are vulnerable to radiation-induced interruptions or failures are identified. Solutions to mitigating the risk of radiation events are proposed through the infusion of RHESE technology products and deliverables into the Constellation program's spacecraft designs.

Keys, Andrew S.; Frazier, Donald O.; Patrick , Marshall C.; Watson, Michael D.; Johnson, Michael A.; Cressler, John D.; Kolawa, Elizabeth A.

2007-01-01

284

Rapid Evaporation of microbubbles  

NASA Astrophysics Data System (ADS)

When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

Gautam, Jitendra; Esmaeeli, Asghar

2008-11-01

285

The long day leaf as a source of cold hardiness inhibitors.  

PubMed

Short photoperiods followed by low temperatures induced cold hardiness in Acer negundo, Viburnum plicatum tomentosum, and Weigela florida. Hardiness was also obtained under long days and natural fall temperatures if the leaves were removed, either manually or by low temperature. Similarly, removal of leaves from plants exposed to long days at 5 degrees brought about an accelerated rate of hardening. These observations suggested the presence of a hardiness inhibitor in the leaves which was counteracted by short days or removal of the leaves. PMID:16656666

Mac Irving, R; Lanphear, F O

1967-10-01

286

Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels  

NASA Technical Reports Server (NTRS)

The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

Humphries, T. S.; Nelson, E. E.

1980-01-01

287

3D transient model for CO II laser hardening  

NASA Astrophysics Data System (ADS)

A 3D numerical model for the surface hardening process simulation carried out by means of a CO2 laser source is presented. The model is able to predict the extension of the treated area into the workpiece, the type of the resulting micro-structure and the optimal laser path strategy in order to minimize the micro-structural softening due to the tempering effect. The Fourier equation is solved using the Finite Difference Method (FDM) applied on a generical grid obtained by means of the domain discretization. The resulting time dependent temperature distribution into the workpiece is used for the evaluation of the induced heating cycle. By calculating the cooling velocity, the micro-structure transformation is determined together with the hardness in every point of the domain. The hardness reduction due to the tempering effect is also predictible. The computational times are small and the software is very suitable in industrial environment in the early stage of the process planning when several simulation runs must be performed. The modeling activity was developed by considering the class of the hypo-eutectoid steel. The experimental tests were realized on a C43 steel plate. The good agreement between the theoretical and experimental results is shown.

Tani, G.; Orazi, L.; Fortunato, A.; Campana, G.; Ascari, A.

2008-01-01

288

Surface hardening of two cast irons by friction stir processing  

NASA Astrophysics Data System (ADS)

The Friction Stir Processing (FSP) was applied to the surface hardening of cast irons. Flake graphite cast iron (FC300) and nodular graphite cast iron (FCD700) were used to investigate the validity of this method. The matrices of the FC300 and FC700 cast irons are pearlite. The rotary tool is a 25mm diameter cylindrical tool, and the travelling speed was varied between 50 and 150mm/min in order to control the heat input at the constant rotation speed of 900rpm. As a result, it has been clarified that a Vickers hardness of about 700HV is obtained for both cast irons. It is considered that a very fine martensite structure is formed because the FSP generates the heat very locally, and a very high cooling rate is constantly obtained. When a tool without an umbo (probe) is used, the domain in which graphite is crushed and striated is minimized. This leads to obtaining a much harder sample. The hardness change depends on the size of the martensite, which can be controlled by the process conditions, such as the tool traveling speed and the load. Based on these results, it was clarified that the FSP has many advantages for cast irons, such as a higher hardness and lower distortion. As a result, no post surface heat treatment and no post machining are required to obtain the required hardness, while these processes are generally required when using the traditional methods.

Fujii, Hidetoshi; Yamaguchi, Yasufumi; Kikuchi, Toshifumi; Kiguchi, Shoji; Nogi, Kiyoshi

2009-05-01

289

A radiation-hardened SOI-based FPGA  

NASA Astrophysics Data System (ADS)

A radiation-hardened SRAM-based field programmable gate array VS1000 is designed and fabricated with a 0.5 ?m partial-depletion silicon-on-insulator logic process at the CETC 58th Institute. The new logic cell (LC), with a multi-mode based on 3-input look-up-table (LUT), increases logic density about 12% compared to a traditional 4-input LUT The logic block (LB), consisting of 2 LCs, can be used in two functional modes: LUT mode and distributed read access memory mode. The hierarchical routing channel block and switch block can significantly improve the flexibility and routability of the routing resource. The VS1000 uses a CQFP208 package and contains 392 reconfigurable LCs, 112 reconfigurable user I/Os and IEEE 1149.1 compatible with boundary-scan logic for testing and programming. The function test results indicate that the hardware and software cooperate successfully and the VS1000 works correctly. Moreover, the radiation test results indicate that the VS1000 chip has total dose tolerance of 100 krad(Si), a dose rate survivability of 1.5 × 1011 rad(Si)/s and a neutron fluence immunity of 1 × 1014 n/cm2.

Xiaowei, Han; Lihua, Wu; Yan, Zhao; Yan, Li; Qianli, Zhang; Liang, Chen; Guoquan, Zhang; Jianzhong, Li; Bo, Yang; Jiantou, Gao; Jian, Wang; Ming, Li; Guizhai, Liu; Feng, Zhang; Xufeng, Guo; Chen, Stanley L.; Zhongli, Liu; Fang, Yu; Kai, Zhao

2011-07-01

290

Dynamic response of two strain-hardened aluminum alloys  

NASA Astrophysics Data System (ADS)

Despite their common usage in armor applications such as lightweight armored vehicles, the dynamic material response of 5083-H131 and 5083-H32 strain-hardened aluminum alloys has not been previously reported in the open literature. Measurement of the dynamic material properties, including the shock Hugoniot equation of state (EOS), provides hydrocode modelers with critical information required for accurate modeling of material response to intense loading. In the work reported here we investigate the Hugoniot EOS and Hugoniot elastic limit over the stress range of 1.5-8.0GPa. All experiments were performed on the Army Research Laboratory 102mm bore single-stage light gas gun. Impact conditions were uniaxial and planar to within 1mrad of tilt. Both direct-impact- and shock-transmission-type experiments were performed using velocity interferometry diagnostics to record particle velocity histories with 0.5ns temporal resolution. The shock Hugoniot for 5083-H131 is extrapolated to 50GPa and compared to the previous high pressure results of Hauver and Melani (1973) [Ballistic Research Laboratory December Technical Report No. BRL 2345, 1973] and to prior shock studies of 5083-O aluminum alloy.

Boteler, J. M.; Dandekar, D. P.

2006-09-01

291

Radiation hardening of final optics for an ICF reactor  

NASA Astrophysics Data System (ADS)

Radiation damage of the final optical components in an Inertial Confinement Fusion (ICF) reactor is a crucial issue for development of a laser-fusion reactor. To some extent, this problem will be encountered in the National Ignition Facility (NIF), but there, the integrated radiation dose will be considerably less than that encountered in a future reactor. This extremely harsh radiation environment necessitates shielding the ICF optics from direct neutron and x-ray bombardment. Several approaches have been suggested, such as the use of grazing incidence metal mirrors or fused silica wedge deflectors. While metal mirrors can withstand a larger radiation dose, their focusing qualities pose problems. Therefore wedge deflectors, originally suggested by Lawrence Livermore National Laboratory (LLNL) staff, represent a promising alternative. Radiation hardening of the fused silica deflectors using a new combined thermal/optical annealing approach is examined here as a method to maintain transmission quality during irradiation. By selection of suitable low impurity, fused silica materials combined with appropriate in situ treatment, such as discussed here, fused silica can be quite resistant to radiation effects. In addition, the wedge deflectors could be periodically replaced with minimal expense.

DelMedico, S. G.; Barnouin, O. M.; Petra, M.; Miley, G. H.

1996-05-01

292

Beam hardening correction in CT myocardial perfusion measurement  

NASA Astrophysics Data System (ADS)

This paper presents a method for correcting beam hardening (BH) in cardiac CT perfusion imaging. The proposed algorithm works with reconstructed images instead of projection data. It applies thresholds to separate low (soft tissue) and high (bone and contrast) attenuating material in a CT image. The BH error in each projection is estimated by a polynomial function of the forward projection of the segmented image. The error image is reconstructed by back-projection of the estimated errors. A BH-corrected image is then obtained by subtracting a scaled error image from the original image. Phantoms were designed to simulate the BH artifacts encountered in cardiac CT perfusion studies of humans and animals that are most commonly used in cardiac research. These phantoms were used to investigate whether BH artifacts can be reduced with our approach and to determine the optimal settings, which depend upon the anatomy of the scanned subject, of the correction algorithm for patient and animal studies. The correction algorithm was also applied to correct BH in a clinical study to further demonstrate the effectiveness of our technique.

So, Aaron; Hsieh, Jiang; Li, Jian-Ying; Lee, Ting-Yim

2009-05-01

293

Hot and Cold  

NSDL National Science Digital Library

In this activity, learners explore temperature changes from chemical reactions by mixing urea with water in one flask and mixing calcium chloride with water in another flask. They observe that the urea flask gets cold and the calcium chloride flask gets hot. The main idea is that some chemical processes release heat energy and are exothermic, while some chemical processes absorb heat energy and are endothermic. This activity is currently used in the Nature of Matter Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners.

Industry, Oregon M.

1997-01-01

294

The Isis cold moderators  

SciTech Connect

ISIS is a pulsed spallation neutron source where neutrons are produced by the interaction of a 160 kW proton beam of energy 800 MeV in a water-cooled Tantalum Target. The fast neutrons produced are thermalized in four moderators: two ambient water, one liquid methane operating at 100K and a liquid hydrogen moderator at 20 K. This paper gives a description of the construction of both cold moderator systems, details of the operating experience and a description of the current development program.

Allen, G. M.; Broome, T. A.; Burridge, R. A.; Cragg, D.; Hall, R.; Haynes, D.; Hirst, J.; Hogston, J. R.; Jones, H. H.; Sexton, J.; Wright, P.

1997-09-01

295

Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming  

NASA Astrophysics Data System (ADS)

The bi-axial experimental equipment developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong-Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing.

Flores, P.; Duchêne, L.; Lelotte, T.; Bouffioux, C.; El Houdaigui, F.; Van Bael, A.; He, S.; Duflou, J.; Habraken, A. M.

2005-08-01

296

Precipitation hardening in the first aerospace aluminum alloy: the wright flyer crankcase.  

PubMed

Aluminum has had an essential part in aerospace history from its very inception: An aluminum copper alloy (with a copper composition of 8 percent by weight) was used in the engine that powered the historic first flight of the Wright brothers in 1903. Examination of this alloy shows that it is precipitation-hardened by Guinier-Preston zones in a bimodal distribution, with larger zones (10 to 22 nanometers) originating in the casting practice and finer ones (3 nanometers) resulting from ambient aging over the last 90 years. The precipitation hardening in the Wright Flyer crankcase occurred earlier than the experiments of Wilm in 1909, when such hardening was first discovered, and predates the accepted first aerospace application of precipitation-hardened aluminum in 1910. PMID:17779943

Gayle, F W; Goodway, M

1994-11-11

297

Hopkins researchers find that a new cancer-fighting strategy would harden cells to prevent metastasis  

Cancer.gov

Existing cancer therapies are geared toward massacring tumor cells, but Johns Hopkins researchers propose a different strategy: subtly hardening cancer cells to prevent them from invading new areas of the body.

298

Proliferation hardening and power flattening of a thorium fusion breeder with triple mixed oxide fuel  

Microsoft Academic Search

The proliferation hardening of the 233U fuel in a thorium fusion breeder has been realised successfully with a homogenous mixture of ThO2, natural-UO2 and CANDU spent nuclear fuel in the form of a triple mixed oxide (TMOX) fuel. The new 233U component will be successfully hardened against proliferation with the help of the 238U component in the natural-UO2 and spent

Sümer ?ahin; Veysel Özceyhan; Hüseyin Yapici

2001-01-01

299

IR and NMR Analyses of Hardening and Maturation of Glass-ionomer Cement  

Microsoft Academic Search

It has been reported that the silicate phase as well as the cross-linking of the polycarboxylic acid by aluminum and calcium ions played an important role in the hardening of glass-ionomer cement. The objective of this study was to investigate the structural change during hardening of the cements by means of infrared (IR) spectroscopy and solid-state nuclear magnetic resonance (NMR)

S. Matsuya; T. Maeda; M. Ohta

1996-01-01

300

Application of Sinter-Hardenable Materials for Advanced Automotive Applications such as Gears, Cams, and Sprockets  

Microsoft Academic Search

Recent demands within the automotive industry have been for applications requiring high hardness, high hardenability, and increased mechanical performance. These often conflicting requirements necessitated the development of new materials that offer high as-sintered hardness and good static\\/dynamic mechanical properties without the added expense of a secondary heat treatment. Traditionally, sinter-hardening materials have offered acceptable hardness but at the expense of

Michael C. Baran; Thomas Prucher; Thomas E. Haberberger; Thomas J. Cornelio

301

Synthesis of a new hardener agent for self-healing epoxy resins  

NASA Astrophysics Data System (ADS)

Actually, the development of smart composites capable of self-repair in aeronautical structures is still at the planning stage owing to complex issues to overcome. One of the critical points in the development of self-healing epoxy resin is related to the impossibility to employ primary amines as hardeners. In this paper, the synthesis of a new hardener for self-healing resins is shown together with applicability conditions/ranges.

Raimondo, Marialuigia; Guadagno, Liberata; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Agovino, Anna

2014-05-01

302

Effect of cobalt additions on the age hardening of Cu4.5Ti alloy  

Microsoft Academic Search

The effects of 0.9 and 1.8 wt% cobalt additions on the age hardening behaviour of Cu-4.5Ti alloy have been investigated. It has been observed that though Co addition results in the refinement of grain size and the Cu-Ti-Co alloys exhibit age hardening (giving rise to peak hardness on aging at 400°C for 16 hours), the peak hardness as well as

S. Nagarjuna; D. S. Sarma

2002-01-01

303

Microstructural Peculiarities and Hardening of Nb After Mechanical Activation and Subsequent Consolidation by Torsion Under Pressure  

NASA Astrophysics Data System (ADS)

Results of investigation of the microstructural peculiarities and regularities of niobium hardening after combined deformation treatment including mechanical activation of the powder in a planetary ball mill and subsequent consolidation by torsion under pressure in Bridgman anvils are presented. The quantitative parameters of grain and defect structure of the examined material are determined in different deformation stages. The main factors determining the specifics of niobium hardening for the considered deformation treatment are discussed.

Ditenberg, I. A.; Denisov, K. I.; Tyumentsev, A. N.; Korchagin, M. A.; Korznikov, A. V.

2014-11-01

304

Strain-hardening in nano-structured single phase steels: mechanisms and control.  

PubMed

The detrimental effect of grain size refinement on the strain hardening is highlighted in single phase steels. A physical based approach for understanding the underlying mechanisms is presented. In order to overcome this limitation a promising metallurgical route exploiting the thermal stability of mechanically induced twins in austenitic steels has been successfully applied to a stainless grade confirming the opportunity to get nano-structured alloys exhibiting high yield stress with high strain-hardening. PMID:23421275

Bouaziz, O; Barbier, D

2012-11-01

305

Polycrystalline modeling of the cyclic hardening\\/softening behavior of an austenitic–ferritic stainless steel  

Microsoft Academic Search

As other metallic materials, in low-cycle fatigue, duplex stainless steels (DSS) exhibit a cyclic hardening, followed by a cyclic softening, before stabilization of the stress. In order to simulate the cyclic hardening\\/softening curves in low-cycle fatigue of an austenitic–ferritic or duplex stainless steel (DSS), a new polycrystalline model is proposed. The polycrystalline model developed by Cailletaud (1992) and Pilvin (1990)

P. Evrard; I. Alvarez-Armas; V. Aubin; S. Degallaix

2010-01-01

306

Sheet metal forming simulation using finite elastoplasticity with mixed isotropic\\/kinematic hardening  

Microsoft Academic Search

A numerical formulation is presented for anisotropic elastoplasticity behavior in finite strain with non-linear isotropic\\/kinematic hardening model. Non-linear kinematic hardening is modeled by the Lemaitre-Chaboche law with the aim of considering cyclic deformation phenomena. User-defined material subroutines are developed based on Hill’s quadratic yield function for both ABAQUS-Explicit (VUMAT) and ABAQUS-Standard (UMAT). For validation purpose, the tension-compression and cyclic shear

Sami Chatti; Narjess Chtioui

2011-01-01

307

Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals  

SciTech Connect

Characterization of material hardening behavior has been investigated by many researchers in the past decades. Experimental investigation of thin sheet metals under cyclic loading has become a challenging issue. A new test fixture has been developed to use with a regular tensile-compression machine (for example, MTS machine). Experimental results of tension-compression tests are presented followed by a review of existing testing methods. Numerical modeling of the tested data is presented using a new kinematic hardening model.

Cheng, Hang Shawn; Lee, Wonoh; Cao Jian [Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Seniw, Mark [Department of Material Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208 (United States); Wang Huiping [General Motors Corporation, Warren, MI 48090 (United States); Chung, Kwansoo [Department of Mechanical Engineering, Intelligent Textile System Research Center, Seoul National University, 56-1 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of)

2007-04-07

308

Asymptotic crack-tip fields for dynamic crack growth in compressive power-law hardening materials  

Microsoft Academic Search

The effect of material compressibility on the stress and strain fields for a mode-I crack propagating steadily in a power-law hardening material is investigated under plane strain conditions. The plastic deformation of materials is characterized by the J2 flow theory within the framework of isotropic hardening and infinitesimal displacement gradient. The asymptotic solutions developed by the present authors [Zhu, X.K.,

Xian-Kui Zhu; Keh-Chih Hwang

2008-01-01

309

Quench-hardening of aluminium and aluminium-magnesium by sub-microscopic defects  

Microsoft Academic Search

Comparison of the effect of ageing on the flow stress of water-quenched and air-cooled aluminium and aluminium-magnesium alloys has clearly demonstrated that the hardening is inversely related to the concentration of visible dislocation loops. Hardening by more highly dispersed vacancy clusters is therefore postulated and the results interpreted in terms of the bowing of moving dislocations pinned by the lattice

D. Hardie; A. D. Michael

1971-01-01

310

Cold Drawn Steel Wires-Processing, Residual Stresses and Ductility-Part I: Metallography and Finite Element Analyses  

SciTech Connect

Cold drawing steel wires lead to an increase of their mechanical strength and to a drop of their ductility. The increase of their mechanical strength has long been related to the reduction of the various material scales by plastic deformation, but the mechanisms controlling their elongation to failure have received relatively little attention. It is usually found that heavily deformed materials show a tendency to plastic strain localization and necking. However, in this paper it is shown that, though the steel wires are plastically deformed up to strain levels as high as 3.5, a significant capability of plastic deformation is preserved in as-drawn wires. This apparent contradiction is resolved by the existence of residual stresses inside the wire. Finite element analyses have been conducted in order to show that residual stresses, inherited from the drawing process, are sufficient to produce a significant hardening effect during a post-drawing tensile test, without introducing any hardening in the local material behavior. The main conclusion of this paper is that once the material has lost its hardening capabilities, residual stresses, inherited from the process, control the elongation of cold drawn wires. The finite element method allowed also the determination of the residual stress field that would lead to the best agreement between the simulated and the experimental stress strain curve of as-drawn wires.

Phelippeau,A.; Pommier, S.; Tsakalakos, T.; Clavel, M.; Prioul, C.

2006-01-01

311

Microstructural analysis of ion-irradiation-induced hardening in inconel 718  

NASA Astrophysics Data System (ADS)

As an assessment for a possible accelerator beam line window material for the US Spallation Neutron Source (SNS) target, performance, radiation-induced hardening and microstructural evolution in Inconel 718 were investigated in both solution annealed (SA) and precipitation hardened (PH) conditions. Irradiations were carried out using 3.5 MeV Fe +, 370 keV He + and 180 keV H + either singly or simultaneously at 200 °C to simulate the damage and He/H production in the SNS target vessel wall. This resulted in systematic hardening in SA Inconel and gradual net softening in the PH material. TEM microstructural analysis showed the hardening was associated with the formation of small loop and faulted loop structures. Helium-irradiated specimens included more loops and cavities than Fe + ion-irradiated specimens. Softening of the PH material was due to dissolution of the ? '/? ? precipitates. High doses of helium were implanted in order to study the effect of high retention of gaseous transmutation products. Simultaneous with the hardening and/or softening due to the displacement damage cascade, helium filled cavities produced additional hardening at high concentrations.

Hashimoto, N.; Hunn, J. D.; Byun, T. S.; Mansur, L. K.

2003-05-01

312

Study on the Influence of the Work Hardening Models Constitutive Parameters Identification in the Springback Prediction  

NASA Astrophysics Data System (ADS)

The main goal of this work is to determine the influence of the work hardening model in the numerical prediction of springback. This study will be performed according with the specifications of the first phase of the "Benchmark 3" of the Numisheet'2005 Conference: the "Channel Draw". Several work hardening constitutive models are used in order to allow a better description of the different material mechanical behavior. Two are classical pure isotropic hardening models described by a power law (Swift) or a Voce type saturation equation. Those two models were also combined with a non-linear (Lemaître and Chaboche) kinematic hardening rule. The final one is the Teodosiu microstructural hardening model. The study is performed for two commonly used steels of the automotive industry: mild (DC06) and dual phase (DP600) steels. The mechanical characterization, as well as the constitutive parameters identification of each work hardening models, was performed by LPMTM, based on an appropriate set of experimental data such as uniaxial tensile tests, monotonic and Bauschinger simple shear tests and orthogonal strain path tests, all at various orientations with respect to the rolling direction. All the simulations were carried out with the CEMUC's home code DD3IMP (contraction of `Deep Drawing 3-D IMPlicit code').

Oliveira, M. C.; Alves, J. L.; Chaparro, B. M.; Menezes, L. F.

2005-08-01

313

Analysis of Hardened Depth Variability, Process Potential, and Measurement Error in Case Carburized Components  

NASA Astrophysics Data System (ADS)

Hardened depth (effective case depth) measurement is one of the most commonly used methods for carburizing performance evaluation. Variation in direct hardened depth measurements is routinely assumed to represent the heat treat process variation without properly correcting for the large uncertainty frequently observed in industrial laboratory measurements. These measurement uncertainties may also invalidate application of statistical control requirements on hardened depth. Gage R&R studies were conducted at three different laboratories on shallow and deep case carburized components. The primary objectives were to understand the magnitude of the measurement uncertainty and heat treat process variability, and to evaluate practical applicability of statistical control methods to metallurgical quality assessment. It was found that ~75% of the overall hardened depth variation is attributed to the measurement error resulting from the accuracy limitation of microhardness equipment and the linear interpolation technique. The measurement error was found to be proportional to the hardened depth magnitude and may reach ~0.2 mm uncertainty at 1.3 mm nominal depth and ~0.8 mm uncertainty at 3.2mm depth. A case study was discussed to explain a methodology for analyzing a large body of hardened depth information, determination of the measurement error, and calculation of the true heat treat process variation.

Rowan, Olga K.; Keil, Gary D.; Clements, Tom E.

2014-12-01

314

Induction of a Hardening Phenomenon and Quantitative Changes of Ceramides in Stratum Corneum  

PubMed Central

Background Hardening phenomenon of human skin after repeated exposure to the irritants is well-known, but the precise mechanism remains elusive. Objective To modify the previous experimental model of hardening phenomenon by repeated applications of two different concentrations of sodium lauryl sulfate (SLS) solutions to Korean healthy volunteers and to investigate the quantitative changes of ceramides in stratum corneum before and after chronic repeated irritation. Methods Eight hundred microliters of distilled water containing 0.1% and 2% SLS was applied for 10 minutes on the forearm of 41 healthy volunteers for 3 weeks. After an intervening 3-week rest, 24-hour patch tests with 1% SLS were conducted on previously irritated sites. Transepidermal water loss (TEWL), erythema index and quantity of ceramide were measured in the stratum corneum before and after irritation. Results TEWL values on the sites preirritated with 2% SLS were lower than those with 0.1% SLS. Hardening phenomenon occurred in 24 volunteers at day 44. The changes in ceramide levels were not significantly higher in the hardened skin than in the non-hardened skin. Conclusion Repetitive stimulation with a higher concentration of SLS can more easily trigger skin hardening. PMID:24648684

Park, Sook Young; Kim, Jin Hye; Cho, Soo Ick; Kim, Kyeong Il; Cho, Hee Jin; Park, Chun Wook; Lee, Cheol Heon

2014-01-01

315

Studies on the Work-Hardening Behavior of AA2219 under Different Aging Treatments  

NASA Astrophysics Data System (ADS)

Uniaxial tensile tests were performed to examine the influence of the precipitation state on the yield strength and work-hardening behavior of AA2219 for different aging treatments. The microstructural observations in four aging treatments ( viz. natural aging, underaging, peak aging, and overaging) were made through transmission electron microscopy (TEM) to understand the type of phase or intermediate stages of the phase present (Guinier-Preston (GP) zones, ??, ?', and ?). To characterize the work-hardening behavior, the analysis of the experimental results has focused on two parameters, viz. the initial work-hardening rate ?max (? d?/ d?) and the slope ( d?/ d?) of the ?- ? plot, which is related to the rate of dynamic recovery. The initial work-hardening rate (?max) first drops as aging proceeds and then increases significantly upon overaging. The large increase in ?max is also associated with a concomitant increase in the slope ( d?/ d?) of the ?- ? curve. The material constants in the differential equation for the dislocation density are evaluated and flow stress vs plastic strain curves are generated using the flow stress contributions from the solid-solution, dislocation, and precipitation hardening. The model predictions are found to be in excellent agreement with the experimental data for a range of precipitation states from underaged (UA) to overaged (OA) conditions. Curves of flow stress due to dislocation hardening with the plastic strain were also generated in the presence of shearable and nonshearable precipitates.

Sharma, V. M. J.; Sree Kumar, K.; Nageswara Rao, B.; Pathak, S. D.

2009-12-01

316

Microstructural Evolution of the 55 Wt Pct Al-Zn Coating During Press Hardening  

NASA Astrophysics Data System (ADS)

Press hardening is increasingly being used to produce ultra-high strength steel parts for passenger cars. Al-Si, Zn, and Zn-alloy coatings have been used to provide corrosion protection to press hardening steel grades. The use of coatings has drawbacks such as coating delamination or liquid metal-induced embrittlement. In the present work, the microstructural evolution of Al-Zn coating during press hardening was studied. The 55 wt pct Al-Zn coating can in principle provide both Al barrier protection and Zn cathodic protection to press hardened steel. During the heat treatment associated with the press hardening, the 55 wt pct Al-Zn alloy coating is converted to an intermetallic surface layer of Fe2Al5 and a FeAl intermetallic diffusion layer. The Zn is separated from both intermetallic compounds and accumulates at grain boundaries and at the surface. This Zn separation process is beneficial in terms of providing cathodic protection to Al-Zn coated press hardening steel.

Lee, Chang Wook; De Cooman, Bruno Charles

2014-09-01

317

Is It A Cold Or The Flu? Symptoms Cold Flu  

E-print Network

Is It A Cold Or The Flu? Symptoms Cold Flu Fever Rare Usual, high (100-102°) Headache be severe 5 STEPS TO TAKE IF YOU GET THE FLU: 1. Stay at home and rest. CDC recommends that you stay home a medical condition that puts you at higher risk of flu complications (like asthma...), call your doctor

O'Toole, Alice J.

318

Is it a Cold or the Flu? Symptoms Cold Flu  

E-print Network

Is it a Cold or the Flu? Symptoms Cold Flu Fever Rare Usual; high (100°F to 102°F, occasionally higher, especially in young children); lasts 3 to 4 days Headache Rare Common General Aches, Pains Slight Usual; at the beginning of the illness Stuffy Nose Common Sometimes Sneezing Usual Sometimes Sore Throat

Weston, Ken

319

Is It a Cold or the Flu? Symptoms Cold Flu  

E-print Network

Is It a Cold or the Flu? Symptoms Cold Flu Fever Rare Usual; high (100°F to 102°F, occasionally higher, especially in young children); lasts 3 to 4 days Headache Rare Common General Aches, Pains Slight Usual; at the beginning of the illness Stuffy Nose Common Sometimes Sneezing Usual Sometimes Sore Throat

Bandettini, Peter A.

320

Radiation Hardened Superconducting Mixed Multipole Magnet Designs for FRIB  

NASA Astrophysics Data System (ADS)

Higher multipole magnets for FRIB may be either superconducting or conventional. The superconducting multipole magnets can be shorter than the conventional version with the same integrated field. If the magnet is in a region with a small amount of ionizing radiation, the superconducting option is attractive because the multipole magnets can be nested, and they can be installed into cold iron. In regions with large amounts of ionizing radiation, the superconducting option is less attractive because of radiation damage and the heat deposited at low temperatures. High and low radiation designs are compared for an octupole nested within a sextupole that can be used in FRIB

Chouhan, S. S.; Green, M. A.; Zeller, A. F.

321

Hardening transition in a one-dimensional model for ferrogels.  

PubMed

We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance. PMID:23742515

Annunziata, Mario Alberto; Menzel, Andreas M; Löwen, Hartmut

2013-05-28

322

Hardening transition in a one-dimensional model for ferrogels  

NASA Astrophysics Data System (ADS)

We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance.

Annunziata, Mario Alberto; Menzel, Andreas M.; Löwen, Hartmut

2013-05-01

323

Aqueous electrochemistry of precipitation-hardened nickel base alloys  

SciTech Connect

An investigation has been conducted to explore the importance of local crack tip electrochemical processes in precipitation-hardened Ni-Cr-Fe alloys driven by galvanic couples between grain boundary precipitates and the local matrix. The electrochemical behavior of {gamma}{prime} (Ni{sub 3}(Al,Ti)) has been determined as a function of titanium concentration, temperature, and solution pH. The electrochemical behavior of Ni-Cr-Fe solid solution alloys has been investigated as a function of chromium content for a series of 10 Fe-variable Cr (6--18%)-balance Ni alloys, temperature, and pH. The investigation was conducted in neutral and pH3 solutions over the temperature range 25--300{degree}C. The results of the investigation show that the electrochemical behavior of these systems is a strong function of temperature and composition. This is especially true for the {gamma}{prime} (Ni{sub 3}(Al,Ti)) system where a transition from active/passive behavior to purely active behavior and back again occurs over a narrow temperature range near 100{degree}C. Behavior of this system was also found to be a strong function of titanium concentration. In all cases, the Ni{sub 3}(Al,Ti) phase was active with respect to the matrix. The peak in activity near 100{degree}C correlates well with accelerated crack growth in this temperature range, observed in nickel-base alloy X-750 heat treated to precipitate {gamma}{prime} on the grain boundaries. 20 refs., 23 figs., 3 tabs.

Hosoya, K.; Ballinger, R.; Prybylowski, J.; Hwang, I.S. (Massachusetts Inst. of Tech., Cambridge, MA (USA))

1990-11-01

324

Cold Dark Matter Resuscitated?  

E-print Network

The Cold Dark Matter (CDM) model has an elegant simplicitly which makes it very predictive, but when its parameters are fixed at their `canonical' values its predictions are in conflict with observational data. There is, however, much leeway in the initial conditions within the CDM framework. We advocate a re-examination of the CDM model, taking into account modest variation of parameters from their canonical values. We find that CDM models with $n=0.8$--0.9 and $h=0.45$--0.50 can fit the available data. Our ``best fit'' CDM model has $n=0.9$, $h=0.45$ and $C_2^{T}/C_2^{S}=0.7$. We discuss the current state of observations which could definitely rule out this model.

Martin White; Douglas Scott; Joe Silk; Marc Davis

1995-08-02

325

Cold isopressing method  

DOEpatents

A cold isopressing method in which two or more layers of material are formed within an isopressing mold. One of the layers consists of a tape-cast film. The layers are isopressed within the isopressing mold, thereby to laminate the layers and to compact the tape-cast film. The isopressing mold can be of cylindrical configuration with the layers being coaxial cylindrical layers. The materials used in forming the layers can contain green ceramic materials and the resultant structure can be fired and sintered as necessary and in accordance with known methods to produce a finished composite, ceramic structure. Further, such green ceramic materials can be of the type that are capable of conducting hydrogen or oxygen ions at high temperature with the object of utilizing the finished composite ceramic structure as a ceramic membrane element.

Chen, Jack C. (Getzville, NY); Stawisuck, Valerie M. (North Tonawanda, NY); Prasad, Ravi (East Amherst, NY)

2003-01-01

326

The status of cold fusion  

NASA Astrophysics Data System (ADS)

This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

Storms, E.

327

Determination of Constant Parameters of Copper as Power-Law Hardening Material at Different Test Conditions  

NASA Astrophysics Data System (ADS)

In this paper a technique has been developed to determine constant parameters of copper as a power-law hardening material by tensile test approach. A work-hardening process is used to describe the increase of the stress level necessary to continue plastic deformation. A computer program is used to show the variation of the stress-strain relation for different values of stress hardening exponent, n and power-law hardening constant, ? . Due to its close tolerances, excellent corrosion resistance and high material strength, in this analysis copper (Cu) has been selected as the material. As a power-law hardening material, Cu has been used to compute stress hardening exponent, n and power-law hardening constant, ? from tensile test experiment without heat treatment and after heat treatment. A wealth of information about mechanical behavior of a material can be determined by conducting a simple tensile test in which a cylindrical specimen of a uniform cross-section is pulled until it ruptures or fractures into separate pieces. The original cross sectional area and gauge length are measured prior to conducting the test and the applied load and gauge deformation are continuously measured throughout the test. Based on the initial geometry of the sample, the engineering stress-strain behavior (stress-strain curve) can be easily generated from which numerous mechanical properties, such as the yield strength and elastic modulus, can be determined. A universal testing machine is utilized to apply the load in a continuously increasing (ramp) manner according to ASTM specifications. Finally, theoretical results are compared with these obtained from experiments where the nature of curves is found similar to each other. It is observed that there is a significant change of the value of n obtained with and without heat treatment it means the value of n should be determined for the heat treated condition of copper material for their applications in engineering fields.

Kowser, Md. A.; Mahiuddin, Md.

2014-11-01

328

Direct observation of Lomer-Cottrell Locks during strain hardening in nanocrystalline nickel by in situ TEM  

NASA Astrophysics Data System (ADS)

Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by using an in situ transmission electron microscope nanoindentation tool, the direct observation of dynamic work hardening event in nanocrystalline nickel. During strain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded show an increase of yield strength from 1.64 to 2.29 GPa during multiple loading-unloading cycles. This study provides both the evidence to explain the roots of work hardening at small length scales and the insight for future design of ductile nanocrystalline metals.

Lee, Joon Hwan; Holland, Troy B.; Mukherjee, Amiya K.; Zhang, Xinghang; Wang, Haiyan

2013-01-01

329

Differential expression of wheat genes during cold acclimation.  

PubMed

Overwintering crops such as winter wheat display significant increase in freezing tolerance during a period of cold acclimation (CA). To gain better understanding of molecular mechanisms of CA, it is important to unravel functions and regulations of CA-associated genes. Differential screening of a cDNA library constructed from cold acclimated crown tissue of winter wheat identified three novel CA-associated cDNA clones. Nucleotide sequence analysis showed that the clones encode a high mobility globular protein (HMGB1), a glycine-rich RNA-binding protein (TaGRP2), and a LEA D-11 dehydrin (DHN14). Accumulation of the three mRNAs during 14 days of CA was differentially regulated. In response to drought, and ABA, DHN14 mRNA rapidly accumulated while HMGB1 and TaGRP2 mRNA levels remained unchanged. The possible functions of each of these genes in cold acclimation are discussed. PMID:17649620

Christov, N K; Yoneyama, S; Shimamoto, Y; Imai, R

2007-01-01

330

Tool wear mechanism in continuous cutting of hardened tool steels  

Microsoft Academic Search

Precision hard turning provides an alternative to grinding in some finishing applications. Rapid tool wear, however, remains an impediment to the process being economically viable. This experimental study investigates microstructural aspects of cubic boron nitride (CBN) tool wear in finish hard turning. Results indicate the following: (1) carbide sizes of the workpiece have significant effects on tool wear; (2) the

Y. Kevin Chou; Chris J. Evans

1997-01-01

331

75 FR 52213 - Cold Treatment Regulations  

Federal Register 2010, 2011, 2012, 2013

...305 [Docket No. APHIS-2006-0050] Cold Treatment Regulations AGENCY: Animal and...phytosanitary treatment regulations for cold treatment enclosures and procedures, including...document requires articles destined for cold treatment to be precooled at or below...

2010-08-25

332

On the radiation-induced soft error performance of hardened sequential elements in advanced bulk CMOS technologies  

Microsoft Academic Search

Test chips built in a 32 nm bulk CMOS technology consisting of hardened and non-hardened sequential elements have been exposed to neutrons, protons, alpha-particles and heavy ions. The radiation robustness of two types of circuit-level soft error mitigation techniques has been tested: 1) SEUT (Single Event Upset Tolerant), an interlocked, redundant state technique, and 2) a novel hardening technique referred

N. Seifert; V. Ambrose; B. Gill; Q. Shi; R. Allmon; C. Recchia; S. Mukherjee; N. Nassif; J. Krause; J. Pickholtz; A. Balasubramanian

2010-01-01

333

Evaluation of sorghum [Sorghum bicolor (L.) Moench] lines and hybrids for cold tolerance under field and controlled environments  

Technology Transfer Automated Retrieval System (TEKTRAN)

Early season cold tolerance in sorghum contributes to emergence, seedling establishment, early vegetative growth, and reduces damping-off diseases under chilling conditions. The objectives of this study were to identify cold tolerant sources and to evaluate and optimize rapid screening techniques un...

334

Acute phase response of serum amyloid A protein and C reactive protein to the common cold and influenza  

Microsoft Academic Search

C reactive protein (CRP) and serum amyloid A protein (SAA) are sensitive and rapid acute phase reactants, and their measurement for monitoring inflammatory disease and assessing the prognosis in secondary amyloidosis is gaining widespread acceptance. The changes in these proteins in eight subjects suffering from natural colds, 15 subjects with experimentally induced colds (rhinoviruses E1, 3, 9, 14, or 31),

J T Whicher; R E Chambers; J Higginson; L Nashef; P G Higgins

1985-01-01

335

Cognitive work hardening: a return-to-work intervention for people with depression.  

PubMed

Mental health claims in the workplace are rising, particularly those due to depression. Associated with this is an increase in disability costs for the employer and the disability insurer, but even more important is the human suffering that results. While treatments are available for the depression there is a gap in interventions that specifically target return-to-work preparation. This paper presents cognitive work hardening, a treatment intervention that can bridge this gap by addressing the unique functional issues inherent in depression with a view to increasing return-to-work success. Cognitive work hardening applies the proven principles of classical work hardening (which has typically been applied to people with physical injuries) to the mental health domain. This paper explains how the occupational therapy principle of occupation and the core competency, enablement, are utilized and applied in cognitive work hardening. Key skills of the occupational therapist are also discussed. In addition, the paper considers the relationship of cognitive work hardening to recovery and mental illness, and the role it plays among workplace-based return-to-work interventions in the current movement toward non-clinical return-to-work interventions. PMID:23676328

Wisenthal, Adeena; Krupa, Terry

2013-01-01

336

Beam hardening effects in grating-based x-ray phase-contrast imaging  

SciTech Connect

Purpose: In this work, the authors investigate how beam hardening affects the image formation in x-ray phase-contrast imaging and consecutively develop a correction algorithm based on the results of the analysis. Methods: The authors' approach utilizes a recently developed x-ray imaging technique using a grating interferometer capable of visualizing the differential phase shift of a wave front traversing an object. An analytical description of beam hardening is given, highlighting differences between attenuation and phase-contrast imaging. The authors present exemplary beam hardening artifacts for a number of well-defined samples in measurements at a compact laboratory setup using a polychromatic source. Results: Despite the differences in image formation, the authors show that beam hardening leads to a similar reduction of image quality in phase-contrast imaging as in conventional attenuation-contrast imaging. Additionally, the authors demonstrate that for homogeneous objects, beam hardening artifacts can be corrected by a linearization technique, applicable to all kinds of phase-contrast methods using polychromatic sources. Conclusions: The evaluated correction algorithm is shown to yield good results for a number of simple test objects and can thus be advocated in medical imaging and nondestructive testing.

Chabior, Michael; Donath, Tilman; David, Christian; Bunk, Oliver; Schuster, Manfred; Schroer, Christian; Pfeiffer, Franz [Siemens AG Corporate Technology, 80200 Muenchen (Germany); Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Siemens AG Corporate Technology, 80200 Muenchen (Germany); Technische Universitaet Dresden, 01062 Dresden (Germany); Technische Universitaet Muenchen, 85748 Garching (Germany)

2011-03-15

337

Therapeutic opportunities for targeting cold pain pathways.  

PubMed

Cold pain is a frequent symptom in neuropathic pain. Compared to other pain modalities, such as heat pain, the mechanisms behind physiological and pathological cold pain remain elusive. Moreover, it is becoming increasingly evident that cold pain pharmacology differs between various neuropathic pain conditions, making mechanism-directed treatment based on an understanding of the underlying pathophysiological mechanisms imperative to achieving clinical success. Here we review the processes of physiological and abnormal cold sensing, the pharmacology of cold nociception, cold hyperalgesia and cold allodynia, and provide an overview of cold pain syndromes and their current and potential treatments. PMID:25316567

Yin, Kathleen; Zimmermann, Katharina; Vetter, Irina; Lewis, Richard J

2015-01-15

338

[The "cold" thyroid nodule].  

PubMed

The main problem posed by an (apparent) solitary thyroid nodule is cancer identification, present in about 10% of the nodules excised surgically. This percent might increase to 25-30% in the cold scintigraphic nodules. Therefore, a combination of all the methods for nodule assessment is necessary: anamnesis, physical examination, functional tests, therapeutic test with tyrosine and thyroid imaging, but mainly the intensive active exploration including puncture-biopsy with a fine needle and exeresis with extemporaneous and paraffin morphological checking. Starting from a two decades' experience of a group of endocrinologists, surgeons, anatomo-pathologists and specialists in nuclear medicine, in 2,289 thyropathies operated--of whom 1691 (poly)nodular goitres and 1,190 non-capturing nodules--the authors suggest an investigation algorithm for achieving a differentiated surgery in terms of the pre- and intraoperative morphological findings. This attitude permitted both the improvement of the surgeries of thyroid cancers and the exeresis of benign nodules under low-risk surgical conditions or avoidance of a "non-necessary" surgery. PMID:2149188

Diaconescu, M R; Strat, V; Chifan, M; Georgescu, S; Bordea, M; Zbranca, E; Mogo?, V; G?le?anu, C; Dobrescu, G; Baran, T

1990-01-01

339

Cold Spring Harbor Laboratory  

NSDL National Science Digital Library

Established in 1890, the Cold Spring Harbor Laboratory (CSHL) is one of the best-known and most respected private research institutions in the United States. Over the past century, the Laboratory has supported the careers of seven Nobel Prize recipients and it is particularly well-regarded for its work in the field of genetics research. Today, there are over 400 scientists who work at the facility in Long Island, and their work ranges across the areas of cancer, neuroscience, genomics, and bioinformatics. Their website is a cornucopia of information on their activities, and first-time visitors should start by reading over the "CSHL Headlines" scrolling updates on the homepage. After that, they can look at the "Research" section. Here they will find overviews of their primary research groups and links to some of their specialized facilities, like the Dolan DNA Learning Center. Most visitors will want to visit the "Library and Archives" section. Here they can learn about CSHL authors' publications and look through the digital collections. The digital collections include tributes to Barbara McClintock, who was awarded the Nobel Prize in 1983, and who worked at the Laboratory for four decades.

340

Friendly units for coldness  

E-print Network

Measures of temperature that center around human experience get lots of use. Of course thermal physics insights of the last century have shown that reciprocal temperature (1/kT) has applications that temperature addresses less well. In addition to taking on negative absolute values under population inversion (e.g. of magnetic spins), bits and bytes turn 1/kT into an informatic measure of the thermal ambient for developing correlations within any complex system. We show here that, in the human-friendly units of bytes and food Calories, water freezes when 1/kT ~200 ZB/Cal or kT ~5 Cal/YB. Casting familiar benchmarks into these terms shows that habitable human space requires coldness values (part of the time, at least) between 0 and 40 ZB/Cal with respect body temperature ~100 degrees F, a range in kT of ~1 Cal/YB. Insight into these physical quantities underlying thermal equilibration may prove useful for budding scientists, as well as the general public, in years ahead.

Fraundorf, P

2006-01-01

341

Cold matter effects and quarkonium production at RHIC and LHC  

NASA Astrophysics Data System (ADS)

In this work we investigate two cold matter effects in J/? and ? production in nuclear collisions at RHIC and LHC, namely the shadowing effect and nuclear absorption. We characterize these effects by estimating the rapidity dependence of some nuclear ratios in pA and AA collisions at RHIC and LHC, RpA = d?pA(J/?,?)/Ad?pp(J/?,?) and RAA = d?AA(J/?,?)/A2d?pp(J/?,?).

Dos Santos, G. S.; Mariotto, C. B.; Gonçalves, V. P.

2013-03-01

342

Microscopic mechanism for cold denaturation  

E-print Network

We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect is the driving force/induces/facilitates cold denaturation. The physical mechanism underlying this phenomenon is identified as the destabilization of hydrophobic contact in favor of solvent separated configurations, the same mechanism seen in pressure induced denaturation. A phenomenological explanation proposed for the mechanism is suggested as being responsible for cold denaturation in real proteins.

Cristiano L. Dias; Tapio Ala-Nissila; Mikko Karttunen; Ilpo Vattulainen; Martin Grant

2007-04-20

343

Plants in a cold climate.  

PubMed Central

Plants are able to survive prolonged exposure to sub-zero temperatures; this ability is enhanced by pre-exposure to low, but above-zero temperatures. This process, known as cold acclimation, is briefly reviewed from the perception of cold, through transduction of the low-temperature signal to functional analysis of cold-induced gene products. The stresses that freezing of apoplastic water imposes on plant cells is considered and what is understood about the mechanisms that plants use to combat those stresses discussed, with particular emphasis on the role of the extracellular matrix. PMID:12171647

Smallwood, Maggie; Bowles, Dianna J

2002-01-01

344

Photosynthetic microorganisms in cold environments  

NASA Astrophysics Data System (ADS)

The polar regions are considered as a model of extraterrestrial ecosystems. Depending on the average temperature, temperature variation and water availability, these conditions could be used as a model of Mars or Europa (e.g. (Elster and Benson, 2004). Two cases are presented: 1) Stable temperature and water availability The environment of cryosestic communities, i.e. organisms living in snow, is characterized by very stable temperature; the diurnal variations do not exceed 1 -2 ° C (Kváderová, 2010) and a are not usually exposed to freeze/thaw. Water is not usually limiting since the water content could reach up to 54 % (Nedbalová et al., 2008). The windblown sediments are important a source of nutrient and could provide protection against the excess of radiation. The nutrient concentrations in the snow are low are depleted rapidly when massive algal blooms forms. Such environment could be found near Mars polar caps or in Europa ice cover. The snow algae are the most important primary producers in snow. Their adaptation strategy is dependent on the developmental stages; the motile stages avoid the harsh conditions (e.g. high light) and sessile stages acclimatize to actual conditions. The main genera Chlamydomonas and Chloromonas (both Chlorophyta) are psychrophilic. Their growth optimum temperature is lower than 15 ° C and their growth is inhibited at temperatures above 20 ° C. 2) Unstable temperature and water availability The deglaciated surfaces, inhabited by lichen communities, are typical by variation in temper-ature and moisture. The temperature could range several tens ° C within a short time and the water availability is usually very limited. Due to temperature variation, the lichens are subjected to many freeze/thaw cycles. Such environments could be found in Martian deserts. The lichens are symbotic organisms composed of a mycobiont (heterotrophic fungi) and photo-bionts (algae and/or cyanobacteria). Majority of lichens are dehydrated in the field and their physiological processes are inactive. If hydrated, they are physiologically active even at subzero temperatures (Kappen et al., 1996). Although living in cold environments, the growth optimum temperature of typical phycobiont Trebouxia (Chlorophyta) sp. is above 15 ° C, so these algae are considered to be rather psychrotolerant. Acknowledgement The work was supported from projects GA AS CR Nos. KJB 601630808 and KJ KJB600050708, CAREX and long-term institutional research plan of the Institute of Botany AS CR AV0Z600050516 and the Masaryk University. Prof. Martin Backor (Safarik University in Kosice) is kindly ac-knowledged for providing the strains Trebouxia erici and T. glomerata (Backor). References Elster, J. , Benson, E.E. Life in the polar terrestrial environment with a focus on algae and cyanobacteria, in Fuller, B.J., Lane, N. , Benson, E.E. (Eds), Life in the Frozen State. CRC Press, pp. 111-150, 2004. Kappen, L., Schroeter, B., Scheidegger, C., Sommerkorn, M. , Hestmark, G. Cold resistance and metabolic activity of lichens below 0 ° C. Adv. Space Res. 18, 119-128, 1996. Kviderova, J. Characterization of the community of snow algae and their photochemical performance in situ in the Giant Mountains, Czech Republic. Arct. Antarct. Alp. Res. accepted, 2010. Nedbalova, L., Kocianova, M. , Lukavsky, J. Ecology of snow algae in the Giant Mountains and their relation to cryoseston in Europe. Opera Corcontica 45, 59-68, 2008.

Kviderova, Jana; Hajek, Josef; Elster, Josef; Bartak, Milos; Vaczi, Peter; Nedbalova, Linda

345

Cold Spraying of Amorphous Cu50Zr50 Alloys  

NASA Astrophysics Data System (ADS)

A new range of applications in cold spraying is expected for bulk metallic glass (BMG) coatings. For retaining amorphous structures in cast multi-component BMG parts, typically high purity raw material must be used. The present investigation explores an alternative approach, where cold spraying is used to deposit a technical-grade binary amorphous alloy. This approach is shown to be potentially cost-effective and suitable for rapid manufacturing. For this purpose, amorphous Cu50Zr50 was chosen as a model alloy system, and cold spraying was performed using nitrogen as process gas. By a systematic variation of the spray parameter sets, the critical velocities for coating formation were determined experimentally. Based on the current models of bonding of amorphous Cu50Zr50 powder in cold spraying, a new, more comprehensive concept of bonding and rebound is presented, which also considers the presence of liquefied interfaces and quenching rates for resolidification. Results concerning impact morphologies and coating formation demonstrate that under suitable choice of spray conditions, well-adhering coatings with amorphous structure of the Cu50Zr50 powders can be obtained by cold spraying.

List, A.; Gärtner, F.; Mori, T.; Schulze, M.; Assadi, H.; Kuroda, S.; Klassen, T.

2014-11-01

346

Cold Spraying of Amorphous Cu50Zr50 Alloys  

NASA Astrophysics Data System (ADS)

A new range of applications in cold spraying is expected for bulk metallic glass (BMG) coatings. For retaining amorphous structures in cast multi-component BMG parts, typically high purity raw material must be used. The present investigation explores an alternative approach, where cold spraying is used to deposit a technical-grade binary amorphous alloy. This approach is shown to be potentially cost-effective and suitable for rapid manufacturing. For this purpose, amorphous Cu50Zr50 was chosen as a model alloy system, and cold spraying was performed using nitrogen as process gas. By a systematic variation of the spray parameter sets, the critical velocities for coating formation were determined experimentally. Based on the current models of bonding of amorphous Cu50Zr50 powder in cold spraying, a new, more comprehensive concept of bonding and rebound is presented, which also considers the presence of liquefied interfaces and quenching rates for resolidification. Results concerning impact morphologies and coating formation demonstrate that under suitable choice of spray conditions, well-adhering coatings with amorphous structure of the Cu50Zr50 powders can be obtained by cold spraying.

List, A.; Gärtner, F.; Mori, T.; Schulze, M.; Assadi, H.; Kuroda, S.; Klassen, T.

2015-01-01

347

Effect of cold work on tensile behavior of irradiated type 316 stainless steel  

SciTech Connect

Tensile specimens were irradiated in ORR at 250, 290, 450, and 500/sup 0/C to produce a displacement damage of approx.5 dpa and 40 at. ppM He. Irradiation at 250 and 290/sup 0/C caused an increase in yield stress and ultimate tensile strength and a decrease in ductility relative to unaged and thermally aged controls. The changes were greatest for the 20%-cold-worked steel and lowest for the 50%-cold-worked steel. Irradiation at 450/sup 0/C caused a slight relative decrease in strength for all cold-worked conditions. A large decrease was observed at 500/sup 0/C, with the largest decrease occurring for the 50%-cold-worked specimen. No bubble, void, or precipitate formation was observed for specimens examined by transmission electron microscopy (TEM). The irradiation hardening was correlated with Frank-loop and ''black-dot'' loop damage. A strength decrease at 500/sup 0/C was correlated with dislocation network recovery. Comparison of tensile and TEM results from ORR-irradiated steel with those from steels irradiated in the High Flux Isotope Reactor and the Experimental Breeder Reactor indicated consistent strength and microstructure changes.

Klueh, R.L.; Maziasz, P.J.

1986-01-01

348

Increase of cold tolerance in cotton plant (Gossypium hirsutum L.) by mepiquat chloride  

NASA Technical Reports Server (NTRS)

Three mepiquat chloride (MC) concentrations - 40, 70, and 100 g a.i./ha - were used to spray cotton (Gossypium hirsutum L., cultival McNair 220) plants to determine whether or not MC would increase their cold tolerance. Seven to ten days after the spray, the plants were exposed to three different cold treatments. No important difference in cold damage was noticed between the control and the MC-treated plants when they were exposed repeatedly to 4.5 C. No plants died when exposed to 0.5 C for 12 h; however, 90% of the 1st and 2nd leaves of the control plants were damaged. This was three times more damage than those leaves of plants treated with 70 and 100 g a.i./ha MC concentrations; 60% f the control and 10-20% of the MC-treated plants died when the plants were subjected to a cold hardening process with 15.5 C day (12 h) and 1.7 C night (12 h) for 10 days, and then, held at -2.2 C for 24 hours. The electrolyte leakage and reflectance measurement data showed that the cell membranes of the MC-treated plants sustained much less damage than those of the control. Freezing injury was easily assessed by reflectance measurements at the 1.65 micrometer wavelength.

Gausman, H. W.; Escobar, D. E.; Rodriguez, R. R. (principal investigators); Huang, S. Y.; Rittig, F. R.

1982-01-01

349

[Cold-induced pathology at high altitude].  

PubMed

Cold injury is an objective danger in mountain climbing as well as in many outdoor and recreational sports such as skiing, fishing, etc. Symptoms are easily recognizable by the experienced, and prevention is mostly possible. Cold injury should be divided by pathological means in general hypothermia and local frostbite injuries. Life-threatening deep hypothermia with coma and insufficient circulation or cardiac arrest is reversible under the condition of sufficient core rewarming, for instance by CEC. Because of the big tolerance of hypothermic patients to hypoxia, clinical death is not like biological death and therefore reversible. Local frostbite is not life-threatening, but has often deleterious effects. Rapid rewarming in warm water of 37 to 42 degrees C is mandatory. After rewarming, the difference between superficial and deep frostbite can be established. Scintigraphy seems to be of great help in setting early prognosis. Daily sterile treatment of the injury, whirlpool bath and prevention of infections belong to standard treatment. There are little objective informations about the role of vasodilators, anticoagulants, antibiotics, sympathectomy and others. Early experience with Prostavasine seems to bee encouraging. PMID:1957091

Segantini, P; Horn, R

1991-11-12

350

Arabidopsis Transcriptome Profiling Indicates That Multiple Regulatory Pathways Are Activated during Cold Acclimation in Addition to the CBF Cold Response PathwayW?  

PubMed Central

Many plants, including Arabidopsis, increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Previous studies established that cold acclimation involves rapid expression of the CBF transcriptional activators (also known as DREB1 proteins) in response to low temperature followed by induction of the CBF regulon (CBF-targeted genes), which contributes to an increase in freezing tolerance. Here, we present the results of transcriptome-profiling experiments indicating the existence of multiple low-temperature regulatory pathways in addition to the CBF cold response pathway. The transcript levels of ?8000 genes were determined at multiple times after plants were transferred from warm to cold temperature and in warm-grown plants that constitutively expressed CBF1, CBF2, or CBF3. A total of 306 genes were identified as being cold responsive, with transcripts for 218 genes increasing and those for 88 genes decreasing threefold or more at one or more time points during the 7-day experiment. These results indicate that extensive downregulation of gene expression occurs during cold acclimation. Of the cold-responsive genes, 48 encode known or putative transcription factors. Two of these, RAP2.1 and RAP2.6, were activated by CBF expression and thus presumably control subregulons of the CBF regulon. Transcriptome comparisons indicated that only 12% of the cold-responsive genes are certain members of the CBF regulon. Moreover, at least 28% of the cold-responsive genes were not regulated by the CBF transcription factors, including 15 encoding known or putative transcription factors, indicating that these cold-responsive genes are members of different low-temperature regulons. Significantly, CBF expression at warm temperatures repressed the expression of eight genes that also were downregulated by low temperature, indicating that in addition to gene induction, gene repression is likely to play an integral role in cold acclimation. PMID:12172015

Fowler, Sarah; Thomashow, Michael F.

2002-01-01

351

Effect of tempering temperature on the work-hardening rate of five HSLA steels  

NASA Astrophysics Data System (ADS)

A series of compression tests were performed to measure the work-hardening characteristics of a variety of quenched and tempered high strength low alloy (HSLA) steels as a function of tempering temperature. All of the steels tested had a minimum in their work-hardening rate when tempered in the range 300° to 450 °C and all exhibited a maximum at 700 °C, the upper limit of the range examined. The steels containing both molybdenum and vanadium exhibited delayed tempering in the range 400° to 600 °C, and this was reflected as an increased work-hardening rate. A discussion on the microstructural changes occurring over the tempering range suggests reasons for the observed behavior.

Winter, P. L.; Woodward, R. L.

1986-02-01

352

Influence of laser hardening and resulting microstructure on fatigue properties of carbon steels  

NASA Astrophysics Data System (ADS)

Cylindrical specimens of a CSN 12050 carbon steel, equivalent to the UNS G 10420 steel, with two different initial microstructures, normalized and heat treated, were surface processed without melting by a 2.5 kW, CO2 laser to study the effects of laserbeam hardening and resulting microstructure on fatigue properties and mechanisms. Two configurations of circumferential laser passes were made, resulting in one and three separate surface hardened lines, respectively. Fatigue resistance was studied using alternating bend tests. A detailed metallographic study and x-ray measurements of surface stresses were carried out. It was shown that the laser beam hardening under different conditions either reduced or slightly improved the fatigue life.

Cerny, I.; Fürbacher, I.; Linhart, V.

1998-06-01

353

a Calorimetric Study of the Precipitation Hardening Mechanisms in AN Al-Cu-Mg-Si Alloy  

NASA Astrophysics Data System (ADS)

The precipitation phenomena and the related hardening in an Al-Cu-Mg-Si alloy were studied by calorimetry, X-ray diffraction analysis and microhardness measurements. The main calorimetric peaks were identified to be due to ???, ?? and Q? phases precipitation. The hardening during aging at room temperature and 160°C, was respectively, explained by atomic clusters and GP zones formation and by GP zones and ???/?? phases coprecipitation. Although the mechanical properties variation during aging at 200°C is simple, the corresponding microstructural evolution is complex: on the basis of the DSC results, the increasing of microhardness values, is mainly due to the coprecipitation of GP zones and ???/?? phases, however, the maximum hardening is explained by the coexistence of ???/?? and ??? phases. Another important conclusion is that during aging at 160°C and 200°C, the ?? phase is essentially developed from GP zones.

Hayoune, Abdelali

2013-08-01

354

Influence of explosive density on mechanical properties of high manganese steel explosion hardened  

NASA Astrophysics Data System (ADS)

The explosion hardening tests of high manganese steel were carried out by using two kinds of explosives of the same composition but different density, respectively. The detonation velocities were tested and the relevant mechanical properties were studied. The results show that the stronger single impulse acting on the specimen, the more hardness of surface increases and the more impact toughness decreases. Compared with the explosive of 1.48 g/cm3 density, the hardness, elongation rate, and impact toughness of the sample for triple explosion with explosive of 1.38 g/cm3 density are larger at the same hardening depth. In addition, the tensile strength of the sample for triple explosion with density of 1.38 g/cm3 is higher from the surface to 15 mm below the surface hardened.

Hu, Xiaoyan; Shen, Zhaowu; Liu, Yingbin; Liu, Tiansheng; Wang, Fengying

2013-12-01

355

Dealing with Cold Weather Injuries  

MedlinePLUS

... this page, please enable JavaScript. Dealing With Cold Weather Injuries Safety precautions can prevent serious problems during ... clothing should be removed and replaced with warm, dry clothes or blankets. People with hypothermia should also ...

356

Cold binary and ternary fission  

Microsoft Academic Search

Summary  Cold binary fission has been studied in the spontaneous decay of252Cf (sf). Cold fission for the mass split 132\\/120 is especially interesting because here it is the doubly magic132 Sn which is dominating the yield for a range of total excitation energies 0 ? TXE ?10MeV For the reaction242Am(n,f) induced by thermal neutrons the yields of the heaviest clusters being

F. Gönnenwein; A. Möller; M. Cröni; M. Hesse; M. Wöstheinrich; H. Faust; G. Fioni; S. Oberstedt

1997-01-01

357

Sinusitis in the common cold  

Microsoft Academic Search

Background: Acute community-acquired sinusitis is considered a bacterial complication of the common cold. Radiologic abnormalities in sinuses occur, however, in most patients with upper respiratory virus infections.Objective: Assessment of the occurrence, clinical profile, laboratory findings, and outcome of radiologically confirmed sinusitis was carried out as part of a common cold study in young adults.Methods: Clinical examinations and radiography of the

Tuomo Puhakka; Mika J. Mäkelä; Anu Alanen; Timo Kallio; Leo Korsoff; Pertti Arstila; Maija Leinonen; Markku Pulkkinen; Jouko Suonpää; Jussi Mertsola; Olli Ruuskanen

1998-01-01

358

Antibiotic use for common cold  

Microsoft Academic Search

Antibiotics do not help patients with an uncomplicated common cold. Antibiotics can have side effects for the individual taking\\u000a them that range from unpleasant to serious, even lethal. Antibiotic use also contributes to communal harm by encouraging antibiotic\\u000a resistance. If there can be no benefit, but there can be harm, why is the common cold the commonest reason for doctors

Timothy W. Kenealy; Bruce Arroll

359

Premixed rapid-setting calcium phosphate composites for bone repair?  

PubMed Central

Although calcium phosphate cement (CPC) is promising for bone repair, its clinical use requires on site powder–liquid mixing. To shorten surgical time and improve graft properties, it is desirable to develop premixed CPC in which the paste remains stable during storage and hardens only after placement into the defect. The objective of this study was to develop premixed CPC with rapid setting when immersed in a physiological solution. Premixed CPCs were formulated using the following approach: Premixed CPC = CPC powder+nonaqueous liquid+gelling agent+hardening accelerator. Three premixed CPCs were developed: CPC–monocalcium phosphate monohydrate (MCPM), CPC–chitosan, and CPC–tartaric. Setting time for these new premixed CPCs ranged from 5.3 to 7.9 min, significantly faster than 61.7 min for a premixed control CPC reported previously (p<05). SEM revealed the formation of nano-sized needle-like hydroxyapatite crystals after 1 d immersion and crystal growth after 7 d. Diametral tensile strength for premixed CPCs at 7 d ranged from 2.8 to 6.4 MPa, comparable to reported strengths for cancellous bone and sintered porous hydroxyapatite implants. Osteoblast cells attained a normal polygonal morphology on CPC–MCPM and CPC–chitosan with cytoplasmic extensions adhering to the nano-hydroxyapatite crystals. In summary, fast-setting premixed CPCs were developed to avoid the powder–liquid mixing in surgery. The pastes hardened rapidly once immersed in physiological solution and formed hydroxyapatite. The cements had strengths matching those of cancellous bone and sintered porous hydroxyapatite and non-cytotoxicity similar to conventional non-premixed CPC. PMID:15769536

Carey, Lisa E.; Xu, Hockin H.K.; Simon, Carl G.; Takagi, Shozo; Chow, Laurence C.

2009-01-01

360

Influence of electrified surface of cementitious materials on structure formation of hardened cement paste  

NASA Astrophysics Data System (ADS)

To provide high strength and durability of concrete it is necessary to study the influence of physical and chemical and mechanical principles of dispersed cementitious systems. The experimental bench was developed to study the influence of electrified surface of cementitious materials on structure formation of hardened cement paste. The test bench allows accelerating the processes of dissolution of cementing materials in water due to influence of electric discharge on their surface. Cement activation with high-voltage corona discharge when AC current is applied allows increasing the ultimate compressive strength of hardened cement paste by 46% at the age of one day and by 20% at the age of 28 days.

Alekseev, A.; Gusakov, A.

2015-01-01

361

Evaluation of a precipitation hardened wrought cobalt-nickel-chromium-titanium alloy for surgical implants.  

PubMed

A Co-Ni-Cr-Ti precipitation hardening alloy is evaluated for use as a surgical implant alloy. Static and fatigue strength studies indicate that the alloy is equivalent, or superior to, present implant alloys. In vitro and in vivo corrosion studies indicate that the material has good general corrosion resistance but may be susceptible to crevice corrosion. However, there appear to be no inherent difficulties in using precipitation hardened alloys for surgical implants and therefore it may be possible to develop a new class of materials possessing ultra-high strength and excellent corrosion resistance for use in surgical implant applications. PMID:739014

Cahoon, J R; Hill, L D

1978-11-01

362

Age Hardening Kinetics in 7xxx Type (Al-Mg-Zn) Alloys  

SciTech Connect

Age hardening in industrial 7xxx alloys at the temperature 100 deg. and 150 deg. C up to 144 hrs, after solid solution treatments at 450 deg. and 550 deg. C, has been followed by measurements of Vickers hardness, scanning and transmission electron microscopy. The influence of silicon on phase and kinetic of age hardening zones and precipitates has been studied. High iron and silicon content increase the number of primary particle in the alloy. Size distribution of {eta}'-precipitates has been determined.

Vevecka-Priftaj, A. [Department of Physic, Polytechnic University of Tirana, Sheshi 'Nene Tereza', N.4, Tirana (Albania); Lamani, E. [Department of Production and Menagement, Polytechnic University of Tirana (Albania); Fjerdingen, J. [Vitec AS, Akervegen2, 7650 Verdal (Norway); Langsrud, Y. [Hydro Aluminum Structures, Raufoss, P.O.Box 15, N-2831 Raufoss (Norway); Gjoennes, J. [Center for Materials Science, University of Oslo, Gaustadalleen 21, N-0349, Oslo (Norway); Hansen, V. [Faculty of Science and Technology, University of Stavanger, N-403, Stavanger (Norway)

2007-04-23

363

Patterning and hardening of gold black infrared absorber by shadow mask deposition with ethyl cyanoacrylate  

NASA Astrophysics Data System (ADS)

Patterning of gold-black infrared absorbing films by stencil lithography and hardening by polymer infusion is reported. Gold black nano-structured films are deposited through a thin metal shadow mask in a thermal evaporator in ~400 mTorr pressure of inert gas, followed by ethyl cyanoacrylate fuming through the same mask to produce rugged IR absorptive patterns of ~100 micron scale dimensions. Infrared absorptivity is determined by transmission and reflectivity measurements using a Fourier spectrometer and infrared microscope. Results indicate that the optimized hardening process reduces the usual degradation of the absorptivity with age. This work has potential application to infrared array bolometers.

Panjwani, Deep; Nader-Esfahani, Nima; Maukonen, Doug; Rezadad, Imen; Boroumand, Javaneh; Smith, Evan; Nath, Janardan; Peale, R. E.

2013-06-01

364

Radiation-hardened 10-bit A/D for FPA signal processing  

NASA Astrophysics Data System (ADS)

Radiation-hardened A/D converters suitable for converting the output of FPA signals in an SDI environment have not been readily available. Hughes developed a 10-bit, 1-MSPS, total-dose and dose-rate hard A/D converter using a proprietary radiation-hardened bulk CMOS process. This paper describes the A/D converter architecture, semiconductor process, and circuit design. Test results show over 1-Mrad(Si) total-dose tolerance and up to 7 x 10 exp 11 rad(Si)/s at 125 C dose rate without latchup. Neutron fluences up to 3 x 10 exp 14 neutrons/sq cm show negligible effects.

Murphy, J. B.; Kim, Eric; Liou, Michael; Yang, John

1992-07-01

365

Strain Hardening in Uniaxial Elongation vs. Temperature for Random Copolymer Melts with High Comonomer Content  

NASA Astrophysics Data System (ADS)

Two metallocene-catalyzed random copolymers with a polyethylene backbone and octene comonomer content of 20 wt% and 38 wt% were tested in uniaxial extensional flow at different temperatures. Sparse LCB was detected in both melts with these measurements. The strain hardening parameter at the lowest strain rate was found to be greater for EO3, the material with the smaller degree of LCB. The temperature dependence of the strain hardening parameter was also greater for EO3 than for EO1. These trends may be related to the two model parameters used by Wagner and coworkers representing branch content and the maximum tube diameter contraction.

Mills, John E.; Jayaraman, Krishnamurthy; Patham, Bhaskar; Dong, Dinshong; Wolkowicz, Michael

2008-07-01

366

Radiation hardening of components and systems for nuclear rocket vehicle applications  

NASA Technical Reports Server (NTRS)

The results of the analysis of the S-2 and S-4B components, although incomplete, indicate that many Saturn 5 components and subsystems, e.g., pumps, valves, etc., can be radiation hardened to meet NRV requirements by material substitution and minor design modifications. Results of these analyses include (1) recommended radiation tolerance limits for over 100 material applications; (2) design data which describes the components of each system; (3) presentation of radiation hardening examples of systems; and (4) designing radiation effects tests to supply data for selecting materials.

Greenhow, W. A.; Cheever, P. R.

1972-01-01

367

Experimental Determination of Process Parameters and Material Data for Numerical Modeling of Induction Hardening  

NASA Astrophysics Data System (ADS)

Induction surface hardening is a widely used manufacturing process to improve the mechanical properties of components. However, better process understanding as well as process development requires numerical modeling. The modeling itself depends on the input data in terms of process parameters and the material behavior. Data acquisition is a rather difficult task due to very short processing times, as seen in contour hardening of gears. The article will give an overview over critical aspects regarding the acquisition of input data. A short presentation of the numerical model used to compare experimental and numerical results shall promote better understanding for improving the modeling or reducing the model complexity necessary for good predictability.

Schwenk, Maximilian; Hoffmeister, Jürgen; Schulze, Volker

2013-07-01

368

Deciphering the Metabolic Changes Associated with Diapause Syndrome and Cold Acclimation in the Two-Spotted Spider Mite Tetranychus urticae  

PubMed Central

Diapause is a common feature in several arthropod species that are subject to unfavorable growing seasons. The range of environmental cues that trigger the onset and termination of diapause, in addition to associated hormonal, biochemical, and molecular changes, have been studied extensively in recent years; however, such information is only available for a few insect species. Diapause and cold hardening usually occur together in overwintering arthropods, and can be characterized by recording changes to the wealth of molecules present in the tissue, hemolymph, or whole body of organisms. Recent technological advances, such as high throughput screening and quantification of metabolites via chromatographic analyses, are able to identify such molecules. In the present work, we examined the survival ability of diapausing and non-diapausing females of the two-spotted spider mite, Tetranychus urticae, in the presence (0 or 5°C) or absence of cold acclimation. Furthermore, we examined the metabolic fingerprints of these specimens via gas chromatography-mass spectrophotometry (GC-MS). Partial Least Square Discriminant Analysis (PLS-DA) of metabolites revealed that major metabolic variations were related to diapause, indicating in a clear cut-off between diapausing and non-diapausing females, regardless of acclimation state. Signs of metabolic depression were evident in diapausing females, with most amino acids and TCA cycle intermediates being significantly reduced. Out of the 40 accurately quantified metabolites, seven metabolites remained elevated or were accumulated in diapausing mites, i.e. cadaverine, gluconolactone, glucose, inositol, maltose, mannitol and sorbitol. The capacity to accumulate winter polyols during cold-acclimation was restricted to diapausing females. We conclude that the induction of increased cold hardiness in this species is associated with the diapause syndrome, rather than being a direct effect of low temperature. Our results provide novel information about biochemical events related to the cold hardening process in the two-spotted spider mite. PMID:23349779

Khodayari, Samira; Moharramipour, Saeid; Larvor, Vanessa; Hidalgo, Kévin; Renault, David

2013-01-01

369

Cold Transiently Activates Calcium-Permeable Channels in Arabidopsis Mesophyll Cells1[W  

PubMed Central

Living organisms are capable of discriminating thermal stimuli from noxious cold to noxious heat. For more than 30 years, it has been known that plant cells respond to cold with a large and transient depolarization. Recently, using transgenic Arabidopsis (Arabidopsis thaliana) expressing the calcium-sensitive protein aequorin, an increase in cytosolic calcium following cold treatment was observed. Applying the patch-clamp technique to Arabidopsis mesophyll protoplasts, we could identify a transient plasma membrane conductance induced by rapid cooling. This cold-induced transient conductance was characterized as an outward rectifying 33 pS nonselective cation channel. The permeability ratio between calcium and cesium was 0.7, pointing to a permeation pore >3.34 Å (ø of cesium). Our experiments thus provide direct evidence for the predicted but not yet measured cold-activated calcium-permeable channel in plants. PMID:17114272

Carpaneto, Armando; Ivashikina, Natalya; Levchenko, Victor; Krol, Elzbieta; Jeworutzki, Elena; Zhu, Jian-Kang; Hedrich, Rainer

2007-01-01

370

Cold acclimation-induced freezing tolerance of Medicago truncatula seedlings is negatively regulated by ethylene.  

PubMed

To evaluate the role of ethylene in cold acclimation and cold stress, freezing tolerance and characteristics associated with cold acclimation were investigated using legume model plant Medicago truncatula Gaertn Jemalong A17. There was a rapid suppression of ethylene production during cold acclimation in A17 plants. Ethylene level was negatively correlated with freezing tolerance as inhibition of ethylene biosynthesis by inhibitors of ethylene biosynthesis enhanced freezing tolerance, while exogenous application of ethylene reduced cold acclimation-induced freezing tolerance. The involvement of ethylene signaling in modulation of freezing tolerance and cold acclimation was further studied using ethylene-insensitive mutant sickle skl. Although skl mutant was more tolerant to freezing than its wild-type counterpart A17 plants, cold acclimation enhanced freezing tolerance in 17 plants, but not in skl mutant. Expression of several ethylene response genes including EIN3, EIN3/EIL and ERFs was suppressed in skl mutant compared to A17 plants under non-cold-acclimated conditions. Cold acclimation downregulated expression of EIN3, EIN3/EIL and ERFs in A17 plants, while expression patterns of these genes were relatively constant in skl mutant during cold acclimation. Cold acclimation-induced increases in transcription of MtCBFs and MtCAS15 were suppressed in skl mutant compared with A17 plants. These results suggest that MtSKL1 is required for perception of the change of ethylene level in M. truncatula plants for the full development of the cold acclimation response by suppressing expression of MtEIN3 and MtEIN3/EIL1, which in turn downregulates expression of MtERFs, leading to the enhanced tolerance of M. truncatula to freezing by upregulating MtCBFs and MtCAS15. PMID:24494928

Zhao, Mingui; Liu, Wenjing; Xia, Xiuzhi; Wang, Tianzuo; Zhang, Wen-Hao

2014-09-01

371

High-temperature rapid-response thermocouple for reducing atmospheres  

NASA Technical Reports Server (NTRS)

Thermocouple measures continuously in flowing gaseous hydrogen at temperatures up to 4000 deg F, in environments made hazardous by radiation, and where rapid response and calibration reproducibility are critically important. Thermocouple wires extend continuously, without splice or foreign material, from cold junction to probe's tip.

Gracey, C. M.; Hoff, R. G.

1970-01-01

372

Phase development in the hardening process of two calcium phosphate bone cements: an energy dispersive X-ray diffraction study  

Microsoft Academic Search

This work was aimed at the application of an energy dispersive X-ray diffraction technique to study the kinetics of phase development during the setting and hardening reactions in two calcium phosphate bone cements. The cements under study are based on either tricalcium phosphate or tetracalcium phosphate initial solid phase, and a magnesium carbonate–phosphoric acid liquid phase as the hardening liquid.

A. Generosi; V. V. Smirnov; J. V. Rau; V. Rossi Albertini; D. Ferro; S. M. Barinov

2008-01-01

373

Influence of hardener on physicochemical and dynamic properties of polyurethanes based on ?,?-di(2-hydroxypropyl)-polybutadiene Krasol LBH-3000  

Microsoft Academic Search

The peculiarities of how hardener influences the structural, physicochemical, dynamic elastic hysteresis, and relaxation properties\\u000a of materials based on oligodienediol Krasol LBH-3000 are established. It is shown that polydieneurethanes hardened under conditions\\u000a where the ratio of the reactive groups is NCO\\/?(OH) ? 0.9?1.25 mol\\/mol have optimal properties.

I. A. Novakov; A. V. Nistratov; V. P. Medvedev; D. V. Pyl’nov; E. B. Myachina; V. A. Lukasik; E. N. Titova; S. Yu. Gugina

2011-01-01

374

Effects of quenching and tempering on the microstructure and bake hardening behavior of ferrite and dual phase steels  

E-print Network

Effects of quenching and tempering on the microstructure and bake hardening behavior of ferrite of both ferrite and dual phase steels were investigated. The C­Mn steels were heated to the soaking. The ferrite aging and the martensite tempering played key roles in the bake hardening behavior during

Volinsky, Alex A.

375

Strain hardening behaviour and deformation kinetics of Cu deformed by equal channel angular extrusion from 1 to 16 passes  

Microsoft Academic Search

The work hardening rate, strain rate sensitivity and the apparent activation volume of copper processed by equal channel angular extrusion (ECAE) for 1–16 passes are investigated. Constant strain rate and strain rate jump tests performed in compression up to 30% of strain reveal stage III and IV work hardening for specimens subjected to less than 4 passes of ECAE, while

F. H. Dalla Torre; E. V. Pereloma; C. H. J. Davies

2006-01-01

376

Finite deformation plasticity and viscoplasticity laws exhibiting nonlinear hardening rules Part I: Constitutive theory and numerical integration  

Microsoft Academic Search

This paper deals with plasticity and viscoplas- ticity laws exhibiting nonlinear kinematic hardening as well as nonlinear isotropic hardening rules. In Tsakmakis (1996a, b) a constitutive theory has been formulated within the framework of finite deformations, which is based on the concept of so-called dual variables and associated time derivatives. Within two families of dual variables, two dif- ferent formulations

E. Diegele; W. Jansohn; Ch. Tsakmakis

377

Garlic for the common cold.  

PubMed

Background Garlic is alleged to have antimicrobial and antiviral properties that relieve the common cold, among other beneficial effects. There is widespread usage of garlic supplements. The common cold is associated with significant morbidity and economic consequences. On average, children have six to eight colds per year and adults have two to four.Objectives To determine whether garlic (Allium sativum) is effective for the prevention or treatment of the common cold, when compared to placebo, no treatment or other treatments.Search methods We searched CENTRAL (2014, Issue 7),OLDMEDLINE (1950 to 1965),MEDLINE (January 1966 to July week 5, 2014), EMBASE(1974 to August 2014) and AMED (1985 to August 2014).Selection criteria Randomised controlled trials of common cold prevention and treatment comparing garlic with placebo, no treatment or standard treatment.Data collection and analysis Two review authors independently reviewed and selected trials from searches, assessed and rated study quality and extracted relevant data.Main results In this updated review, we identified eight trials as potentially relevant from our searches. Again, only one trial met the inclusion criteria.This trial randomly assigned 146 participants to either a garlic supplement (with 180 mg of allicin content) or a placebo (once daily)for 12 weeks. The trial reported 24 occurrences of the common cold in the garlic intervention group compared with 65 in the placebo group (P value < 0.001), resulting in fewer days of illness in the garlic group compared with the placebo group (111 versus 366). The number of days to recovery from an occurrence of the common cold was similar in both groups (4.63 versus 5.63). Only one trial met the inclusion criteria, therefore limited conclusions can be drawn. The trial relied on self reported episodes of the common cold but was of reasonable quality in terms of randomisation and allocation concealment. Adverse effects included rash and odour. Authors' conclusions There is insufficient clinical trial evidence regarding the effects of garlic in preventing or treating the common cold. A single trial suggested that garlic may prevent occurrences of the common cold but more studies are needed to validate this finding. Claims of effectiveness appear to rely largely on poor-quality evidence. PMID:25386977

Lissiman, Elizabeth; Bhasale, Alice L; Cohen, Marc

2014-01-01

378

PUBLISHER'S NOTE: Rapid Communications Rapid Communications  

NASA Astrophysics Data System (ADS)

As part of a general review of Superconductor Science and Technology, we have been examining the scope for Rapid Communications (RAPs). We recognize these articles make up an important part of the journal representing the latest state-of-the-art research in superconductivity. To reflect this, we have devised a new scope for this article type: 'Rapid Communications. The journal offers open access to outstanding short articles (no longer than 5 journal pages or 4500 words including figures) reporting new and timely developments in superconductivity and its applications. These articles should report very substantial new advances in superconductivity to the readers of Superconductor Science and Technology, but are not expected to meet any requirement of 'general interest'. RAPs will be processed quickly (average receipt to online publication for RAPs is around 60 days) and are permanently free to read in the electronic journal. Authors submitting a RAP should provide reasons why the work is urgent and requires rapid publication. Each RAP will be assessed for suitability by our Reviews and Rapid Communications Editor before full peer review takes place.' The essential points are: They should report very substantial new advances in superconductivity and its application; They must be no longer than 5 journal pages long (approx. 4500 words); Average publication time for a Rapid Communication is 60 days; They are free to read. As mentioned in the previous publisher's announcement (2009 Supercond. Sci. Technol. 22 010101), each submitted Rapid Communication must come with a letter justifying why it should be prioritized over regular papers and will be pre-assessed by our Reviews and Rapid Communications Editor. In addition, we will work with the authors of any Rapid Communication to promote and raise the visibility of the work presented in it. We will be making further changes to the journal in the near future and we write to you accordingly. Thank you for your kind attention and I look forward to receiving your next Rapid Communication.

Miller, Tom

2009-09-01

379

Analysis of hardening behavior of sheet metals by a new simple shear test method taking into account the Bauschinger effect  

NASA Astrophysics Data System (ADS)

In this study we establish a process to predict hardening behavior considering the Bauschinger effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Bauschinger effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with FEA. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments.

Bang, Sungsik; Rickhey, Felix; Kim, Minsoo; Lee, Hyungyil; Kim, Naksoo

2013-12-01

380

Numerical Study of Cold Store in Cold Storage Supply Chain and Logistics  

Microsoft Academic Search

The management of cold storage chain is an important part of the management of supply chain and logistics. The development of Chinese cold storage chain logistics is relatively backward, which affects the food industry seriously. Cold store play an important role in cold storage chain logistics. The field flow is the key technological parameter in cold store. A three dimensional

Gong Jianying; Pu Liang; Zhang Huajun

2010-01-01

381

Rapid shallow breathing  

MedlinePLUS

Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... your oxygen level is too low and nebulized respiratory treatments if you are having an asthma attack.

382

Identification of the hardening law of materials with spherical indentation using the average  

E-print Network

, published in "Materials Science and Engineering: A 606 (2014) 409-416" DOI : 10.1016/j.msea.2014.03.123 #12Identification of the hardening law of materials with spherical indentation using the average Rennes Cedex, France. 3 Faurecia Automotive Seating, Le Pont de Vère, 61100 Caligny, France Corresponding

383

Expression and analysis of pore fluids from hardened cement pastes and mortars  

Microsoft Academic Search

A device is described that has been used for several years for expression of pore solution from hardened portland cement pastes and mortars. Particulars with respect to the design, fabrication, and operation of such equipment are given, and methods for the analysis of the resulting small volumes of pore solutions are briefly discussed. It is believed that the compositions of

R. S. Jr. Barneyback; S. Diamond

1981-01-01

384

Correlation of microscopic structures to the strain rate hardening of SPCC steel  

Microsoft Academic Search

The high strain rate properties of steel have been studied for accurate crashworthiness of vehicles. The mechanical properties at high strain rates show different characteristics from those at the quasi-static state. In order to seek for the physical phenomenon of the strain rate hardening, a microscopic investigation has been conducted for the texture evolution and dislocation behavior of steel.Tensile tests

Hoon Huh; Jong-Hun Yoon; Chan-Gyung Park; Ju-Seok Kang; Moo-Young Huh; Hyung-Gu Kang

2010-01-01

385

Plastic Behavior of Metals in the StrainHardening Range. Part II  

Microsoft Academic Search

In order to observe the behavior of a material under various conditions of strain-hardening, copper bars were tested in tension, in compression and in torsion. The results of the different tests were plotted on the same set of coordinates as a means of correlation. The shearing stress in the octahedral planes was used as ordinates and the corresponding octahedral shearing

Evan A. Davis

1937-01-01

386

Workload-driven selective hardening of control state elements in modern microprocessors  

E-print Network

Workload-driven selective hardening of control state elements in modern microprocessors Michail elements against soft errors in modern microprocessors. In order to effectively allocate resources, our the high degree of architectural masking inherent in modern microprocessors. The novelty of our method lies

Makris, Yiorgos

387

Multi-species beam hardening calibration device for x-ray microtomography  

NASA Astrophysics Data System (ADS)

Impact-source X-ray microtomography (XMT) is a widely-used benchtop alternative to synchrotron radiation microtomography. Since X-rays from a tube are polychromatic, however, greyscale `beam hardening' artefacts are produced by the preferential absorption of low-energy photons in the beam path. A multi-material `carousel' test piece was developed to offer a wider range of X-ray attenuations from well-characterised filters than single-material step wedges can produce practically, and optimization software was developed to produce a beam hardening correction by use of the Nelder-Mead optimization method, tuned for specimens composed of other materials (such as hydroxyapatite [HA] or barium for dental applications.) The carousel test piece produced calibration polynomials reliably and with a significantly smaller discrepancy between the calculated and measured attenuations than the calibration step wedge previously in use. An immersion tank was constructed and used to simplify multi-material samples in order to negate the beam hardening effect of low atomic number materials within the specimen when measuring mineral concentration of higher-Z regions. When scanned in water at an acceleration voltage of 90 kV a Scanco AG hydroxyapatite / poly(methyl methacrylate) calibration phantom closely approximates a single-material system, producing accurate hydroxyapatite concentration measurements. This system can then be corrected for beam hardening for the material of interest.

Evershed, Anthony N. Z.; Mills, David; Davis, Graham

2012-10-01

388

On Hardening Leakage Resilience of Random Extractors for Instantiations of Leakage Resilient Cryptographic  

E-print Network

On Hardening Leakage Resilience of Random Extractors for Instantiations of Leakage Resilient Abstract Random extractors are proven to be important building blocks in construct- ing leakage resilient could become the point of inter- est. This paper extends the problem of how leakage resilience of random

389

In-Plane Strain Solution of Stress and Defects of Tube Bending with Exponential Hardening Law  

Microsoft Academic Search

Approximate equations are derived based upon in-plane strain assumption in tube bending with exponential hardening law to provide quantitative methods for predicting stresses in different directions, Von Mises stress, neutral layer (NL) shift, wall thickness variation, and cross section flattening under rotary draw bending. It was revealed that calculated values of stresses are positively correlated with strength coefficient and negatively

Daxin E; Jisheng Chen; Jie Ding; Xue Bai

2012-01-01

390

Efficient simulation of press hardening process through integrated structural and CFD analyses  

SciTech Connect

Press hardened steel parts are being increasingly used in automotive structures for their higher strength to meet safety standards while reducing vehicle weight to improve fuel consumption. However, manufacturing of sheet metal parts by press hardening process to achieve desired properties is extremely challenging as it involves complex interaction of plastic deformation, metallurgical change, thermal distribution, and fluid flow. Numerical simulation is critical for successful design of the process and to understand the interaction among the numerous process parameters to control the press hardening process in order to consistently achieve desired part properties. Until now there has been no integrated commercial software solution that can efficiently model the complete process from forming of the blank, heat transfer between the blank and tool, microstructure evolution in the blank, heat loss from tool to the fluid that flows through water channels in the tools. In this study, a numerical solution based on Altair HyperWorks® product suite involving RADIOSS®, a non-linear finite element based structural analysis solver and AcuSolve®, an incompressible fluid flow solver based on Galerkin Least Square Finite Element Method have been utilized to develop an efficient solution for complete press hardening process design and analysis. RADIOSS is used to handle the plastic deformation, heat transfer between the blank and tool, and microstructure evolution in the blank during cooling. While AcuSolve is used to efficiently model heat loss from tool to the fluid that flows through water channels in the tools. The approach is demonstrated through some case studies.

Palaniswamy, Hariharasudhan [Altair, 1820 East Big Beaver Road, Troy, MI 48083 (United States); Mondalek, Pamela; Wronski, Maciek [Altair Development France, Sophia Antipolis Cedex 06903 (France); Roy, Subir [Altair, 1820 East Big Beaver Road, Troy, MI 48083 (France)

2013-12-16

391

Patterning and hardening of Gold Black infrared absorber by shadow mask deposition with Ethyl Cyanoacrylate  

E-print Network

Patterning and hardening of Gold Black infrared absorber by shadow mask deposition with Ethyl is reported. Gold black nano-structured films are deposited through a thin metal shadow mask in a thermalTM "). 2. EXPERIMENT Gold black is deposited by the method of Harris.[1] Thick, porous films of gold black

Peale, Robert E.

392

Processing, Microstructures and Properties of a Dual Phase Precipitation-Hardening PM Stainless Steel  

Microsoft Academic Search

To improve the mechanical properties of PM stainless steels in comparison with their wrought counterparts, a PM stainless steel alloy was developed which combines a dual-phase microstructure with precipitation-hardening. The use of a mixed microstructure of martensite and ferrite results in an alloy with a combination of the optimum properties of each phase, namely strength and ductility. The use of

Christopher Schade

2010-01-01

393

Update on radiation-hardened microcomputers for robotics and teleoperated systems  

SciTech Connect

Since many programs sponsored by the Department of Defense are being canceled, it is important to select carefully radiation-hardened microprocessors for projects that will mature (or will require continued support) several years in the future. At the present time there are seven candidate 32-bit processors that should be considered for long-range planning for high-performance radiation-hardened computer systems. For Department of Energy applications it is also important to consider efforts at standardization that require the use of the VxWorks operating system and hardware based on the VMEbus. Of the seven processors, one has been delivered and is operating and other systems are scheduled to be delivered late in 1993 or early in 1994. At the present time the Honeywell-developed RH32, the Harris RH-3000 and the Harris RHC-3000 are leading contenders for meeting DOE requirements for a radiation-hardened advanced 32-bit microprocessor. These are all either compatible with or are derivatives of the MIPS R3000 Reduced Instruction Set Computer. It is anticipated that as few as two of the seven radiation-hardened processors will be supported by the space program in the long run.

Sias, F.R. Jr. [Clemson Univ., SC (United States). Dept. of Electrical and Computer Engineering; Tulenko, J.S. [Univ. of Florida, Gainesville, FL (United States). Dept. of Nuclear Engineering Science

1993-12-31

394

The swelling, microstructure, and hardening of wrought LCAC, TZM, and ODS molybdenum following neutron irradiation  

NASA Astrophysics Data System (ADS)

TEM examinations and swelling measurements were performed on commercially available wrought Low Carbon Arc Cast (LCAC), La-oxide Oxide Dispersion Strengthened (ODS), and TZM molybdenum alloys following irradiation in the High Flux Isotope Reactor (HFIR) at 300 °C, 600 °C, and 900 °C to neutron fluences between 1.05 and 24.7 × 10 25 n/m 2 ( E > 0.1 MeV), or 0.6-13.1 dpa. The defect structure, hardening, and swelling were shown to be strongly dependent on irradiation temperature and starting microstructure. Irradiation at 300 °C results in the formation of a high number density of fine loops and voids (˜1 nm) that produce significant hardening and low swelling that is comparable for all alloys. Irradiation at 600 °C-784 °C produces a high number density of larger voids (5-6 nm) that results in significant hardening with the highest swelling. A low number density of the largest void sizes (8-30 nm) are formed for the 900 °C irradiation that result in low hardening and less swelling than observed for the 600 °C irradiation. The fine grain size of ODS Mo results in a higher concentration of denuded zones along grain boundaries and improved ductile-laminate toughening that results in improved resistance to irradiation embrittlement for the 600 °C irradiations. Irradiation-induced formation of precipitates rich in transmutation products is observed at the highest dose, and it is likely that these features exert an influence on subsequent void growth.

Cockeram, B. V.; Smith, R. W.; Hashimoto, N.; Snead, L. L.

2011-11-01

395

Characterization of Radiation Hardened Bipolar Linear Devices for High Total Dose Missions  

NASA Technical Reports Server (NTRS)

Radiation hardened linear devices are characterized for performance in combined total dose and displacement damage environments for a mission scenario with a high radiation level. Performance at low and high dose rate for both biased and unbiased conditions is compared and the impact to hardness assurance methodology is discussed.

McClure, Steven S.; Harris, Richard D.; Rax, Bernard G.; Thorbourn, Dennis O.

2012-01-01

396

"Deviance Proneness" and Adolescent Smoking 1980 versus 2001: Has There Been a "Hardening" of Adolescent Smoking?  

ERIC Educational Resources Information Center

In a midwestern community sample, we tested for evidence of "hardening" of adolescent cigarette smoking between 1980 and 2001 by comparing adolescent smokers and nonsmokers at these two times on measures indicative of "deviance proneness" in Jessor and Jessor's [Jessor, R., & Jessor, S. L. (1977). "Problem behavior and psychosocial development: A…

Chassin, Laurie; Presson, Clark; Morgan-Lopez, Antonio; Sherman, Steven J.

2007-01-01

397

RHrFPGA Radiation-Hardened Re-programmable Field-Programmable Gate Array  

NASA Technical Reports Server (NTRS)

Viewgraphs on the development of the Radiation-Hardened Re-programmable Field-Programmable Gate Array (RHrFPGA) are presented. The topics include: 1) Radiation Test Suite; 2) Testing Interface; 3) Test Configuration; 4) Facilities; 5) Test Programs; 6) Test Procedure; and 7) Test Results. A summary of heavy ion and proton testing is also included.

Sanders, A. B.; LaBel, K. A.; McCabe, J. F.; Gardner, G. A.; Lintz, J.; Ross, C.; Golke, K.; Burns, B.; Carts, M. A.; Kim, H. S.

2004-01-01

398

SEU hardening of field programmable gate arrays (FPGAs) for space applications and device characterization  

Microsoft Academic Search

Field Programmable Gate Arrays (FPGAs) are being used in space applications because of attractive attributes: good density, moderate speed, low cost, and quick turn-around time. However, these devices are susceptible to Single Event Upsets (SEUs). An approach using triple modular redundancy (TMR) and feedback was developed for flip-flop hardening in these devices. Test data showed excellent results for this circuit

R. Katz; R. Barto; P. McKerracher; B. Carkhuff; R. Koga

1994-01-01

399

Laser hardening of AISI 52100 bearing steel with a discrete fiber laser spot  

NASA Astrophysics Data System (ADS)

Surface hardening with discrete laser spot treatment is an interesting solution since the adoption of a single pulse allows the treatment of different surface geometries avoiding the effect of back tempering. The aim of this work is to find a suitable process window in which operate to get best results in terms of hardness, diameter and depth of the treated region. A single pulse out of a fiber laser source impinging on a bearing hypereutectoid steel was used using different power values, pulse energy and defocussing distances, in order to get the optimal process parameters. The dimensions of the hardened zone and its hardness were then acquired and related to the laser process parameters, to the prior microstructure of the steel (spheroidized and tempered after oil quenching) and to the roughness on the specimen before the laser treatment. Experimental results highlighted that both the surface condition (in terms of roughness) and the initial steel microstructure have a great influence on the achieved hardness values and on the dimension of the laser hardened layer. The pulse energy and power strongly affected the dimension of the hardened layer, too.

Sorgente, Donato; Corizzo, Ottavio; Ancona, Antonio; Scintilla, Leonardo D.; Palumbo, Gianfranco; Tricarico, Luigi

2014-02-01

400

Joining precipitation-hardened nickel-base alloys by friction welding  

NASA Technical Reports Server (NTRS)

Solid state deformation welding process, friction welding, has been developed for joining precipitation hardened nickel-base alloys and other gamma prime-strengthened materials which heretofore have been virtually unweldable. Method requires rotation of one of the parts to be welded, but where applicable, it is an ideal process for high volume production jobs.

Moore, T. J.

1972-01-01

401

Case-hardening medium carbon steel for tough and long life bearing under severe lubrication conditions  

SciTech Connect

It is known these days that case-hardening bearings have a longer life than through-hardening ones under severe lubrication conditions (i.e., mixing-in of foreign particles in the lubrication oil). To explain this fact, the authors first presented the mechanism of stress relaxation at the debris dent edge. According to test results, it was found that both retained austenite and hardness are the most important factors for a longer life material. Such material has a longer life even under boundary lubrication conditions. Since a sufficient EHL oil film does not form under boundary lubrication conditions, metal contact occurs. The resulting damage is called peeling and it decreases the bearing life. To realize ideal case hardening material for bearings, a new carbo-nitride heat treatment has been developed. Normally, it is extremely difficult to obtain a sufficient case depth using a traditional carbo-nitride heat treatment process. As an alternate, medium carbon steel was studied. The application of newly developed medium carbon steel has not only proved to make the creation of a sufficient case depth easier, but also provided economic benefits. Based on results from testing both the dimensional stability and fracture toughness, newly developed medium carbon steel can be used for case-hardening bearings.

Furumura, Kyozaburo; Murakami, Yasuo; Abe, Tsutomu [NSK Ltd., Fujisawa (Japan). Research and Development Center

1998-12-31

402

Hardening behavior of three metallic alloys under combined stresses at elevated temperature  

Microsoft Academic Search

Summary. Initial and subsequent yield loci for type 316 stainless steel, Haynes 188, and Inconel 718 are determined experimentally in the axial-shear stress plane at 650 °C. Each of these materials has a face centered cubic (fcc) crystal structure, but entirely different chemical compositions and strengthening mechanisms. Material hardening behavior is described along three cyclic strain paths having a maximum

C. J. Lissenden; J. F. Colaiuta; B. A. Lerch

2004-01-01

403

ORIGINAL PAPER Combined effects of pre-hardening and fall fertilization  

E-print Network

ORIGINAL PAPER Combined effects of pre-hardening and fall fertilization on nitrogen translocation status is important for outplanting success. Fall fertilization of evergreen conifer seedlings is a well, the interaction of N status prior to fall fertilization and the rate of fall fertilization have yet to be fully

404

Copper precipitation in cobalt-alloyed precipitation-hardened stainless steel  

E-print Network

Copper precipitation in cobalt-alloyed precipitation-hardened stainless steel Arpana S. Murthy online 1 March 2012 The influence of cobalt addition on precipitation of copper in a high precipitate size with narrowed distribution was observed in cobalt-containing steel. The concentration profile

Medvedeva, Julia E.

405

Aluminum-matrix electrotechnical composite alloys hardened by endogenous nano- and microphases  

NASA Astrophysics Data System (ADS)

A method is developed to manufacture aluminum-matrix composite alloys hardened by endogenous nano- and microphases. The formation of the structure and properties of the composite materials is studied. The experimental results demonstrate that the developed alloys are promising to produce electro-technical wire rods and other electrotechnical products.

Babkin, V. G.; Terent'ev, N. A.; Cherepanov, A. I.

2014-09-01

406

Linearization beam-hardening correction method for x-ray computed tomographic imaging of structural ceramics  

Microsoft Academic Search

A linearization beam hardening (BH) correction procedure which takes into account the material composition and the x-ray spectrum of the CT scanner being used, can correct for BH effects and reduce it to a level less than 1%. Further reduction of the BH effect to the 0.1% level may not be possible as scattering effects are present. Theoretically, a special

E. Segal; W. A. Ellingson; Y. Segal; I. Zmora

1986-01-01

407

X-ray computed tomography for structural ceramic applications: Beam hardening corrections  

Microsoft Academic Search

Beam hardening (BH), caused by the energy dependence of x-ray attenuation in materials, reduces the reliability of images generated by computed tomographic (CT) when polychromatic x-ray sources are used. The magnitude of the BH effect was calculated, and four different approaches to BH correction for CT imaging of ceramics were investigated: the ''water bag'' approach, prehardening of the beam by

W. A. Ellingson; E. Segal; M. W. Vannier

1987-01-01

408

Effect of environmental conditions on the properties of fresh and hardened concrete  

Microsoft Academic Search

The effect of varying environmental conditions, at the time of casting on the properties of fresh and hardened concrete was evaluated. The influence of air temperature, wind velocity, and relative humidity on plastic shrinkage, compressive strength, pulse velocity and pore structure of concrete was investigated. Results indicate that exposure conditions at the time of casting significantly affect plastic shrinkage of

Abdullah A Almusallam

2001-01-01

409

Nondestructive Monitoring of Setting and Hardening of Portland Cement Mortar with Sonic Methods  

E-print Network

Nondestructive Monitoring of Setting and Hardening of Portland Cement Mortar with Sonic Methods on the shear wave reflection method. Introduction The nondestructive, in-situ testing of early-age concrete post-tensioning with greatest efficiency. A nondestructive, ultrasonic technique, which measures

410

Efficient simulation of press hardening process through integrated structural and CFD analyses  

NASA Astrophysics Data System (ADS)

Press hardened steel parts are being increasingly used in automotive structures for their higher strength to meet safety standards while reducing vehicle weight to improve fuel consumption. However, manufacturing of sheet metal parts by press hardening process to achieve desired properties is extremely challenging as it involves complex interaction of plastic deformation, metallurgical change, thermal distribution, and fluid flow. Numerical simulation is critical for successful design of the process and to understand the interaction among the numerous process parameters to control the press hardening process in order to consistently achieve desired part properties. Until now there has been no integrated commercial software solution that can efficiently model the complete process from forming of the blank, heat transfer between the blank and tool, microstructure evolution in the blank, heat loss from tool to the fluid that flows through water channels in the tools. In this study, a numerical solution based on Altair HyperWorks® product suite involving RADIOSS®, a non-linear finite element based structural analysis solver and AcuSolve®, an incompressible fluid flow solver based on Galerkin Least Square Finite Element Method have been utilized to develop an efficient solution for complete press hardening process design and analysis. RADIOSS is used to handle the plastic deformation, heat transfer between the blank and tool, and microstructure evolution in the blank during cooling. While AcuSolve is used to efficiently model heat loss from tool to the fluid that flows through water channels in the tools. The approach is demonstrated through some case studies.

Palaniswamy, Hariharasudhan; Mondalek, Pamela; Wronski, Maciek; Roy, Subir

2013-12-01

411

Size Effects on Surface Generation in Micro Milling of Hardened Tool Steel  

Microsoft Academic Search

This paper presents the results of an extensive experimental investigation concerning size effects on surface generation by ball nose and flat end micro milling hardened tool steel. Cutting parameters were selected on the basis of a modular description of the uncut chip geometry. A theoretical model of the generated surfaces was used as a reference and compared with measurement results

G. Bissacco; H. N. Hansen; L. De Chiffre

2006-01-01

412

Single event transient (SET) sensitivity of radiation hardened and COTS voltage comparators  

Microsoft Academic Search

The single event transient (SET) sensitivity of a radiation hardened voltage comparator type with vertical input transistors is compared with that observed for a COTS device type made up of lateral transistors. The cause of the difference in sensitivity is investigated

S. H. Crain; K. B. Crawford; S. C. Moss; S. D. LaLumondiere

2000-01-01

413

Experimental investigation on cubic boron nitride turning of hardened AISI 52100 steel  

Microsoft Academic Search

This study investigated the performance and wear behavior of different cubic boron nitride (CBN) tools in finish turning of hardened AISI 52100 steel. Tool performance was evaluated based on the part surface finish and the tool flank wear. Wear conditions of CBN cutting tools were primarily characterized by scanning electron microscopy (SEM). Machining results showed that low CBN content tools

Y. Kevin Chou; Chris J. Evans; Moshe M. Barash

2003-01-01

414

Application of the central composite design in optimization of laser transformation hardening parameters of commercially pure titanium using Nd:YAG laser  

Microsoft Academic Search

In this study, the application of response surface methodology (RSM) and central composite design for modeling, optimization,\\u000a and an analysis of the influences of dominant laser-processing parameters namely: laser power (LP), scanning speed (SS), and\\u000a focused position (FP) on heat input (HI) and hardened bead geometries such as hardened bead width (HBW), hardened depth (HD),\\u000a angle of entry of hardened

Duradundi Sawant Badkar; Krishna Shankar Pandey; G. Buvanashekaran

415

Treatment of the common cold.  

PubMed

The common cold is a viral illness that affects persons of all ages, prompting frequent use of over-the-counter and prescription medications and alternative remedies. Treatment focuses on relieving symptoms (e.g., cough, nasal congestion, rhinorrhea). Dextromethorphan may be beneficial in adults with cough, but its effectiveness has not been demonstrated in children and adolescents. Codeine has not been shown to effectively treat cough caused by the common cold. Although hydrocodone is widely used and has been shown to effectively treat cough caused by other conditions, the drug has not been studied in patients with colds. Topical (intranasal) and oral nasal decongestants have been shown to relieve nasal symptoms and can be used in adolescents and adults for up to three days. Antihistamines and combination antihistamine/decongestant therapies can modestly improve symptoms in adults; however, the benefits must be weighed against potential side effects. Newer nonsedating antihistamines are ineffective against cough. Topical ipratropium, a prescription anticholinergic, relieves nasal symptoms in older children and adults. Antibiotics have not been shown to improve symptoms or shorten illness duration. Complementary and alternative therapies (i.e., Echinacea, vitamin C, and zinc) are not recommended for treating common cold symptoms; however, humidified air and fluid intake may be useful without adverse side effects. Vitamin C prophylaxis may modestly reduce the duration and severity of the common cold in the general population and may reduce the incidence of the illness in persons exposed to physical and environmental stresses. PMID:17323712

Simasek, Madeline; Blandino, David A

2007-02-15

416

Mathematical modeling of cold cap  

SciTech Connect

The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional (1D) mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.

Pokorny, Richard; Hrma, Pavel R.

2012-10-13

417

Mathematical modeling of cold cap  

NASA Astrophysics Data System (ADS)

The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass, and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.

Pokorny, Richard; Hrma, Pavel

2012-10-01

418

Spectroscopy with cold and ultra-cold neutrons  

E-print Network

We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the \\RB drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron $\\beta$-decay. We aim for a precision on the 10$^{-4}$ level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.

Hartmut Abele; Tobias Jenke; Gertrud Konrad

2014-12-16

419

The Mode of Deformation in a Cold-Swaged Multifunctional Ti-Nb-Ta-Zr-O Alloy  

NASA Astrophysics Data System (ADS)

Multifunctional titanium alloys, termed Gum Metal™, are ?-phase Ti alloys first developed in 2003. These alloys exhibit many interesting properties including, for example, low rate of work-hardening and superplasticity during cold deformation. The original report described a new plastic deformation mechanism not involving major dislocation activity to explain such deformation behavior. In the current study, a comparable Ti-36.8Nb-2.7Zr-2.0Ta-0.44O (wt pct) alloy to the original investigators was produced by powder sintering, hot forging, solution treatment, and cold swaging with the aim at investigating the microstructural development during swaging. XRD and TEM showed that the forged/solution-treated alloy was ?-phase with a small amount of ?-phase. After cold swaging by up to 96 pct area reduction, TEM/HRTEM revealed the existence of dislocations, deformation twins, ?-phase, nanodisturbances, and lattice bending, with EBSD showing the grains to be highly elongated in the swaging direction, fragmented, and distorted. Most notably, swaging also generated a strong <110> fiber texture, even after moderate strains. The foregoing structural analysis provides substantial evidence that dislocations are present in the alloy after cold swaging. The major support of dislocation glide processes acting as the dominant plastic deformation mode in the swaged alloy is the strong <110> fiber texture that develops, which is a characteristic feature of all cold-drawn/swaged body centered cubic metals and alloys.

Guo, W.; Quadir, M. Z.; Ferry, M.

2013-05-01

420

Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy  

NASA Astrophysics Data System (ADS)

In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

Ghosh, S. K.

2014-09-01

421

Liquation Microfissuring in the Weld Heat-Affected Zone of an Overaged Precipitation-Hardened Nickel-Base Superalloy  

NASA Astrophysics Data System (ADS)

The effect of preweld overaging heat treatment on the microstructural response in the heat-affected zone (HAZ) of a precipitation-hardened nickel-base superalloy INCONEL 738LC subjected to the welding thermal cycle ( i.e., rapid) was investigated. The overaging heat treatment resulted in the formation of an interfacial microconstituent containing M23X6 particles and coarsening of primary and secondary ?' precipitates. The HAZ microstructures around welds in the overaged alloy were simulated using the Gleeble thermomechanical simulation system. Microstructural examination of simulated HAZs and those present in tungsten inert gas (TIG) welded specimens showed the occurrence of extensive grain boundary liquation involving liquation reaction of the interfacial microconstituents containing M23X6 particles and MC-type carbides. In addition, the coarsened ?' precipitate particles present in the overaged alloy persisted well above their solvus temperature to temperatures where they constitutionally liquated and contributed to considerable liquation of grain boundaries, during continuous rapid heating. Intergranular HAZ microfissuring, with resolidified product formed mostly on one side of the microfissures, was observed in welded specimens. This suggested that the HAZ microfissuring generally occurred by decohesion across one of the solid-liquid interfaces during the grain boundary liquation stage of the weld thermal cycle. Correlation of simulated HAZ microstructures with hot ductility properties of the alloy revealed that the temperature at which the alloy exhibited zero ductility during heating was within the temperature range at which grain boundary liquation was observed. The on-cooling ductility of the alloy was significantly damaged by the on-heating liquation reaction, as reflected by the considerably low ductility recovery temperature (DRT). Important characteristics of the intergranular liquid that could influence HAZ microfissuring of the alloy in overaged condition are also discussed.

Ojo, O. A.; Chaturvedi, M. C.

2007-02-01

422

Cold Induction of Arabidopsis CBF Genes Involves Multiple ICE (Inducer of CBF Expression) Promoter Elements and a Cold-Regulatory Circuit That Is Desensitized by Low Temperature1  

PubMed Central

The Arabidopsis CBF1, 2, and 3 genes (also known as DREB1b, c, and a, respectively) encode transcriptional activators that have a central role in cold tolerance. CBF1-3 are rapidly induced upon exposing plants to low temperature, followed by expression of CBF-targeted genes, the CBF regulon, resulting in an increase in plant freezing tolerance. At present, little is known about the cold-sensing mechanism that controls CBF expression. Results presented here indicate that this mechanism does not require a cold shock to bring about the accumulation of CBF transcripts, but instead, absolute temperature is monitored with a greater degree of input, i.e. lower temperature, resulting in a greater output, i.e. higher levels of CBF transcripts. Temperature-shift experiments also indicate that the cold-sensing mechanism becomes desensitized to a given low temperature, such as 4°C, and that resensitization to that temperature requires between 8 and 24 h at warm temperature. Gene fusion experiments identified a 125-bp section of the CBF2 promoter that is sufficient to impart cold-responsive gene expression. Mutational analysis of this cold-responsive region identified two promoter segments that work in concert to impart robust cold-regulated gene expression. These sequences, designated ICEr1 and ICEr2 (induction of CBF expression region 1 or 2), were also shown to stimulate transcription in response to mechanical agitation and the protein synthesis inhibitor, cycloheximide. PMID:14500791

Zarka, Daniel G.; Vogel, Jonathan T.; Cook, Daniel; Thomashow, Michael F.

2003-01-01

423

A forest model of latent hardening and its application to polycrystal deformation  

SciTech Connect

This paper means to assess latent hardening effects on large-scale polycrystal deformation on the basis of the dislocation theory of plastic flow and of a wide variety of experimental observations on single crystals. The qualifier large-scale is introduced to eliminate effects during the earliest stages of flow, where mono- and polycrystals behave differently: the authors will not consider easy glide in single crystals; and they will not consider the gradual transition, over perhaps ten times the elastic strain, to polyslip in polycrystals; or, for that matter, initial Lueders-type deformation in polycrystals. In terms of dislocation theory, they will consider the flow stress to mean the percolation limit of dislocations in areal glide. Dislocation theory will be used at a rather gross level. Experience has shown that many of the details of the interactions between dislocations and of their arrangement are of surprisingly little influence on macroscopic plastic behavior. They will present a latent hardening model that is based on the well established forest model of flow stress and strain hardening. They will present a latent hardening model that is based on the well established forest model of flow stress and strain hardening. They will then assess various pieces of experimental and theoretical evidence that limit the number and magnitude of the parameters and predict the direction in which they might depend on stacking-fault energy. Finally, they will summarize results obtained by polycrystal simulation in which the model was implemented. They show only marginal effects, and only in certain cases.

Kocks, U.F. (Los Alamos National Lab., NM (USA)); Franciosi, P. (Paris-13 Univ., 93 - Villetaneuse (France)); Kawai, M. (Tsukuba Univ., Ibaraki (Japan). Inst. of Engineering Mechanics)

1990-01-01

424

Earthquake nucleation size in cohesive or healed rocks: Effects of strain hardening and loading profiles  

NASA Astrophysics Data System (ADS)

Earthquakes are generated because faults lose strength with increasing slip and slip rate. A widely used representation of slip-dependent strength is the linear slip-weakening model, characterised by a single weakening rate. However, fault rocks (especially healed gouges) often exhibit some slip strengthening before the onset of weakening, for instance due to the growth of microcracks needed to reactivate the slip surface. Here we investigate the effect of such a slip-hardening phase on the nucleation of rupture instabilities, with emphasis on the critical nucleation length. We assume a piecewise linear strength vs. slip constitutive relation. We compute the stress and slip distribution for an in-plane or anti-plane rupture configuration in response to an increasing, locally peaked (parabolic with curvature ?), background stress profile. Our calculations show that the curvature of the loading profile, and the level of background stress strongly influence the critical crack size. Even for small amounts of slip hardening, we find that the critical nucleation size scales with 1/?? for ??0, i.e., crack growth remains stable up to very large crack sizes for sufficiently smooth loading profile. Likewise, when the background stress ?b is very close to the strength at which slip onsets (?c), the critical crack size scales with (?c - ?b)n, where n ranges from 0.5 to 1. For moderate curvatures and sufficiently low background stress (?b significantly below ?c), the critical crack size remains close to the one predicted for pure linear slip weakening (within a factor of 2 to 6, depending on the hardening rate and hardening distance). Overall, our results indicate that earthquake nucleation sizes can significantly increase due to slip hardening (e.g., in healed fault rocks), especially when the background loading in smooth.

Brantut, N.; Viesca, R. C.

2013-12-01

425

Is it a Cold or the Flu? -Know the Difference Signs & Symptoms Cold Flu  

E-print Network

Is it a Cold or the Flu? - Know the Difference Signs & Symptoms Cold Flu Onset Gradual Sudden Fever.rochester.edu/uhs (Check Care for Colds & Flu in "Health Topics.") Centers for Disease Control www.cdc.gov/flu University

Mahon, Bradford Z.

426

Method of manufacturing metallic products such as sheet by cold working and flash annealing  

DOEpatents

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

Hajaligol, Mohammad R. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

2000-01-01

427

Method of manufacturing metallic products such as sheet by cold working and flash anealing  

DOEpatents

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

Hajaligol, Mohammad R. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

2001-01-01

428

Effect of Feeding Rate on the Cold Cap Configuration in a Laboratory-Scale Melter - 13362  

SciTech Connect

High-level-waste melter feed is converted into glass in a joule-heated melter, where it forms a floating layer of reacting feed, called the cold cap. After the glass-forming phase becomes connected, evolving gases produce bubbles that form a foam layer under the feed. The bubbles coalesce into cavities, from which most of the gases are released around the edges of the cold cap while gases also escape through small shafts in the reacting feed. The foam layer insulates the cold cap from the heat transferred from the molten glass below. The cold cap behavior was investigated in a laboratory-scale assembly with a fused silica crucible. A high-alumina waste simulant was fed into the crucible and the feed charging rate was varied from 3 to 7 mL min{sup -1}. After a fixed amount of time (35 min), feed charging was stopped and the crucible was removed from the furnace and quenched on a copper block to preserve the structure of the cold cap during cooling. During the rapid quenching, thermal cracking of the glass and cold cap allowed it to be broken up into sections for analysis. The effect of the charging rate on the height, area and volume of the cold cap was determined. The size of the bubbles collected in the foam layer under the feed increased as the cold cap expanded and the relationship between these bubbles and temperature will be determined for input into a mathematical model. (authors)

Dixon, Derek R.; Schweiger, Michael J. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)] [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Hrma, Pavel [Pacific Northwest National Laboratory, Richland, WA 99354 (United States) [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of)

2013-07-01

429

COLD-SAT dynamic model  

NASA Technical Reports Server (NTRS)

This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

Adams, Neil S.; Bollenbacher, Gary

1992-01-01

430

Avionics Box Cold Plate Damage Prevention  

NASA Technical Reports Server (NTRS)

Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

2012-01-01

431

Cold agglutinin activity in 2 dogs.  

PubMed

A 5-year-old neutered male Mastiff and an 8-year-old spayed female Labrador Retriever were presented to the University of Minnesota Veterinary Medical Center. The Mastiff was presented for evaluation of lameness and pyoderma one month prior in Missouri, where he tested positive for Ehrlichia canis by serum ELISA test, treated with doxycycline. PCR for Ehrlichia sp, Anaplasma sp, Babesia sp, and Bartonella sp, and PCR for antigen receptor rearrangement were negative, serum protein electrophoresis (SPE) revealed polyclonal gammopathy, and mildly reactive lymphoid cells were seen cytologically. The Labrador presented with a proliferative rostral mandibular gingival mass and lipomas for further presurgical evaluation of cold agglutinin activity documented by a commercial laboratory 2 years earlier prior to removal of a grade II mast cell tumor. This dog had a negative SNAP4Dx, normal SPE, and persistently increased serum ALP activity and polyuria/polydipsia suggestive for hyperadrenocorticism. Both dogs had markedly agglutinated RBC in the EDTA samples that dispersed with warming, and normal plasma color. Cold agglutinin activity was demonstrated by direct saline agglutination testing using whole blood and washed erythrocytes demonstrating agglutination at 30°C, 25°C, 15°C, and 4°C, but not at 37°C. CBC results (ADVIA 2120i) from the Mastiff revealed no significant differences in the RBC results obtained at room temperature (RT) and at 37°C; however, the RT run demonstrated negative bias in neutrophil and platelet concentrations attributed to rapid RBC settling. This uncommon hematologic condition may cause artifacts on the automated leukogram and platelet count, and may be subclinical for long periods. PMID:25056251

Rojas-Temahuay, Gabriela; Crain, Sarah; Benson, Catherine; Sharkey, Leslie; Nothnagel, Geneva

2014-09-01

432

Images of the Cold War.  

ERIC Educational Resources Information Center

The conventional U.S. picture traces the Cold War to Soviet violation of wartime agreements, while the U.S.S.R. defends its actions as responses to American violations and foreign adventurism. An understanding of how ideology is shaped by national self-interest will help students see beyond propaganda and myth in interpreting past and current…

Chomsky, Noam

1989-01-01

433

Cold plasma decontamination of foods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold plasma is a novel nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. This flexible sanitizing method uses electricity and a carrier gas such as air, oxygen, nitrogen or helium; antimicrobi...

434

Hot, Cold, Fresh and Salty  

NSDL National Science Digital Library

In this activity, learners observe the effects of the layering of warm and cold water and water that is more or less saline than regular water. They will discover how the effects of salinity and temperature are the root cause of thermohaline layering in the ocean.

Roth, Jerry; Service, Noaa O.

435

Complement, cold agglutinins, and therapy.  

PubMed

In this issue of Blood, Shi and coworkers show that TNT003, a mouse monoclonal antibody targeting complement protein C1s, prevents induction of in vitro hemolysis by cold agglutinins (CA). If successfully transferred into the clinical setting by further studies, these findings may result in a novel therapeutic principle for a frequently difficult problem. PMID:24970929

Berentsen, Sigbjørn

2014-06-26

436

Magnetoacoustic Emission Characteristics on Cold Rolled Low Carbon Steel  

NASA Astrophysics Data System (ADS)

This paper describes the behaviours of magnetoacoustic emission (MAE) of cold rolled low carbon steel specimens. The MAE rms voltage and the moving average analysis were used for evaluating the profiles of MAE signals. The MAE rms voltage and the peak value of averaged rms voltage rise rapidly with increasing cold rolling below 10 % reduction ratio, and then they decreases at higher reduction ratio, whereas the magnetizing current when the averaged rms voltage takes a peak decreases up to 10 % reduction ratio, then becomes constant value. As a result of the observation of microstructures by transmission electron microscopy, the dislocations increases homogeneously up to 10 % reduction ratio, and then forms cell structures without a significant increase in dislocation density. The behaviours of MAE are attributed to the combined effects of cell texture and dislocation density.

Kikuchi, H.; Matsumura, K.; Fujiwara, T.; Ara, K.; Kamada, Y.; Kobayashi, S.

2011-01-01

437

Bright Source of Cold Ions for Surface-Electrode Traps  

NASA Astrophysics Data System (ADS)

We produce large numbers of low-energy ions by photoionization of laser-cooled atoms inside a surface-electrode-based Paul trap. The isotope-selective trap loading rate of 4x10^5 ^174Yb^+ ions/s exceeds that attained by photoionization (electron impact ionization) of an atomic beam by four (six) orders of magnitude. Our high loading rate could enable rapid, isotope-selective loading of large ion trap arrays for use in quantum computing or atomic clocks. The ions are confined in the same spatial region as the laser-cooled atoms, which will also allow experimental investigation of the interactions between cold ions and cold atoms.

Cetina, Marko; Grier, Andrew; Campbell, Jonathan; Chuang, Isaac; Vuletic, Vladan

2007-06-01

438

Rapid Treatment of Rhinophyma with Powered Microdebrider  

PubMed Central

We describe here our experience in using sinus microdebrider to rapidly debulk and sculpt the tissues in cases of rhinophyma correction. We utilized the use of the 4?mm M4 Rotatable Cutting Straight Sinus Blade on a straight Straightshot M4 Microdebrider by Medtronic at 800 rpm oscillation which is normally utilised in our sinus surgery practice. The microdebrider is straightforward to use and is already stocked in most ENT departments. It requires no additional training or cost outlay for departments that perform endoscopic sinus surgery with microdebrider. In our experience it affords the surgeon the ability to rapidly and accurately sculpt the nose to an excellent aesthetic result. We feel it is a more precise tool than cold steel or Bovie cautery, quicker than CO2 laser techniques, and avoids the aerosol of dermabrasion. No complications occurred in our series, and all patients rated their cosmetic outcome as good to excellent. PMID:23509654

Faris, C.; Manjaly, J. G.; Ismail-Koch, H.; Caldera, S.

2013-01-01

439

EBSD characterization of twinning in cold-rolled CP-Ti  

SciTech Connect

This work presents the use of a mechanical testing system and the electron backscatter diffraction technique to study the mechanical properties and twinning systems of cold-rolled commercial purity titanium, respectively. The dependence of twinning on the matrix orientation is analyzed by the distribution map of Schmid factor. The results showed that the commercial purity titanium experienced strong strain hardening and had excellent formability during rolling. Both the (112{sup ¯}2)<112{sup ¯}3{sup ¯}> compressive twins and (101{sup ¯}2)<101{sup ¯}1{sup ¯}> tensile twins were dependent on the matrix orientation. The Schmid factor of a grain influenced the activation of a particular twinning system. The specific rolling deformation of commercial purity titanium controlled the number and species of twinning systems and further changed the mechanical properties. - Highlights: • CP-Ti experienced strain hardening and had excellent formability. • Twins were dependent on the matrix orientation. • Schmid factor of a grain influenced the activation of a twinning system. • Rolling deformation controlled twinning systems and mechanical properties.

Li, X., E-mail: csulixu@hotmail.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Duan, Y.L., E-mail: 876270744@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Xu, G.F., E-mail: csuxgf66@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Changsha 410083 (China); Peng, X.Y., E-mail: pxy0807@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Dai, C., E-mail: li-xu@nim.ac.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Zhang, L.G., E-mail: 290571871@qq.com [Zunyi Titanium Industry Co. Ltd., Zunyi 563004 (China); Li, Z., E-mail: lizhou6931@mail.csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

2013-10-15

440

Tips to Protect Workers in Cold Environments  

MedlinePLUS

... Anti-Retaliation Tips To Protect Workers In Cold Environments Prolonged exposure to freezing or cold temperatures may ... Tips include: How to Protect Workers Recognize the environmental and workplace conditions that may be dangerous. Learn ...

441

Vitamin C and the Common Cold Revisited.  

ERIC Educational Resources Information Center

Various studies indicate that Vitamin C does not prevent or cure a cold, but it may ameliorate symptoms in some individuals. The development of a balanced life-style is more effective towards cold prevention. (DF)

Travis, H. Richard

1984-01-01

442

Common cold - how to treat at home  

MedlinePLUS

... Antibiotics are almost never needed to treat a common cold. Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) help lower ... Many home remedies are popular treatments for the common cold. These include vitamin C, zinc supplements, and Echinacea. ...

443

Photosynthesis, photoinhibition and low temperature acclimation in cold tolerant plants.  

PubMed

Cold acclimation requires adjustment to a combination of light and low temperature, conditions which are potentially photoinhibitory. The photosynthetic response of plants to low temperature is dependent upon time of exposure and the developmental history of the leaves. Exposure of fully expanded leaves of winter cereals to short-term, low temperature shiftsinhibits whereas low temperature growthstimulates electron transport capacity and carbon assimilation. However, the photosynthetic response to low temperature is clearly species and cultivar dependent. Winter annuals and algae which actively grow and develop at low temperature and moderate irradiance acquire a resistance to irradiance 5- to 6-fold higher than their growth irradiance. Resistance to short-term photoinhibition (hours) in winter cereals is a reflection of the increased capacity to keep QA oxidized under high light conditions and low temperature. This is due to an increased capacity for photosynthesis. These characteristics reflect photosynthetic acclimation to low growth temperature and can be used to predict the freezing tolerance of cereals. It is proposed that the enhanced photosynthetic capacity reflects an increased flux of fixed carbon through to sucrose in source tissue as a consequence of the combined effects of increased storage of carbohydrate as fructans in the vacuole of leaf mesophyll cells and an enhanced export to the crown due to its increased sink activity. Long-term exposure (months) of cereals to low temperature photoinhibition indicates that this reduction of photochemical efficiency of PS II represents a stable, long-term down regulation of PS II to match the energy requirements for CO2 fixation. Thus, photoinhibition in vivo should be viewed as the capacity of plants to adjust photosynthetically to the prevailing environmental conditions rather than a process which necessarily results in damage or injury to plants. Not all cold tolerant, herbaceous annuals use the same mechanism to acquire resistance to photoinhibition. In contrast to annuals and algae, overwintering evergreens become dormant during the cold hardening period and generally remain susceptible to photoinhibition. It is concluded that the photosynthetic response to low temperatures and susceptibility to photoinhibition are consequences of the overwintering strategy of the plant species. PMID:24317651

Huner, N P; Oquist, G; Hurry, V M; Krol, M; Falk, S; Griffith, M

1993-07-01

444

The cold equation of state of tantalum  

SciTech Connect

In high-pressure isentropic compression experiments (ICE), the pressure is dominated by the cold curve. In order to obtain an accurate semi-empirical cold curve for Ta, we calculate the thermal pressure from ab initio phonon and electronic excitation spectra. The cold curve is then inferred from ultrasonic and shock data. Our empirical cold pressure is compared to density functional calculations and found to be closer to GGA results at low pressure and to approach LDA at high pressure.

Greeff, Carl W [Los Alamos National Laboratory; Rudin, Sven P [Los Alamos National Laboratory; Corckett, Scott D [Los Alamos National Laboratory; Wills, John M [Los Alamos National Laboratory

2009-01-01

445

Finite element analysis of roll bit behaviors in cold foil rolling process  

NASA Astrophysics Data System (ADS)

To investigate roll bite behaviors in cold foil rolling process, a 2D elasto-plastic finite model is established using FEM software ABAQUS. Contact pressure distribution and roll contour in roll bite are also presented, which demonstrate that foil rolling process is different from conventional strip rolling process. The contact area is composed of entry elastic zone, entry plastic zone, an extensive neutral zone, exit plastic zone and exit elastic zone. It conforms to the results of Fleck foil rolling theory. Elastic deformation and work hardening of foil in roll bite are taken into account. The effect of rolling parameters, such as friction coefficient, entry thickness and reduction rate on distribution of contact pressure and vertical displacement are also discussed.

Hao, Liang; Jiang, Zhengyi; Wei, Dongbin; Chen, Xiawei

2013-05-01

446

Prediction of beam hardening artefacts in computed tomography using Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

We show how radiological images of both single and multi material samples can be simulated using the Monte Carlo simulation tool McXtrace and how these images can be used to make a three dimensional reconstruction. Good numerical agreement between the X-ray attenuation coefficient in experimental and simulated data can be obtained, which allows us to use simulated projections in the linearisation procedure for single material samples and in that way reduce beam hardening artefacts. The simulations can be used to predict beam hardening artefacts in multi material samples with complex geometry, illustrated with an example. Linearisation requires knowledge about the X-ray transmission at varying sample thickness, but in some cases homogeneous calibration phantoms are hard to manufacture, which affects the accuracy of the calibration. Using simulated data overcomes the manufacturing problems and in that way improves the calibration.

Thomsen, M.; Knudsen, E. B.; Willendrup, P. K.; Bech, M.; Willner, M.; Pfeiffer, F.; Poulsen, M.; Lefmann, K.; Feidenhans'l, R.

2015-01-01

447

Nanostructure control of age-hardenable Al 2024 alloy by high-pressure torsion  

NASA Astrophysics Data System (ADS)

A concurrent strengthening process by high-pressure torsion (HPT) and fine precipitation hardening of an Al 2024 alloy has been studied. The HPT was conducted on disks of the alloys under an applied pressure of 6 GPa for 0.75 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~240 nm and to an increase in hardness up to a saturation after 5 turns. Aging treatment is performed for sample after 5 turns at temperatures of 423 K for a maximum period up to 256 hours. The hardness increased above the hardness level after HPT processing through the subsequent aging. This study thus suggests that simultaneous hardening due to grain refinement and fine precipitation occurred by a combination of HPT processing and subsequent aging at 423 K.

Fadhlina Mohamed, Intan; Lee, Seungwon; Horita, Zenji

2014-08-01

448

An Atomistic-Based Hierarchical Multiscale Examination of Age Hardening in an Al-Cu Alloy  

NASA Astrophysics Data System (ADS)

A large class of modern structural alloys derives its strength from precipitation hardening. Precipitates obstruct the motion of dislocations and thereby increase alloy strength. This paper examines the process using an atomistic-based hierarchical multiscale modeling framework. Atomistic modeling is employed to (1) compute solute-dislocation interaction energies for input into a semi-analytic solute hardening model and (2) evaluate precipitate strengths for use in dislocation line tension simulations. The precipitate microstructure in the dislocation line tension simulations is obtained from simple analytic precipitation kinetics relations. Fitting only the rate constants in the precipitation kinetics model, the macroscopic strength predictions of the hierarchical multiscale model are found to correspond reasonably well with experiments. By analyzing the potential sources of discrepancy between the model's macroscopic predictions and experiments, this work illuminates the importance of specific atomic-scale processes and highlights important challenges that remain before truly predictive mechanism-based plasticity modeling can be realized.

Singh, Chandra Veer; Warner, Derek H.

2013-06-01

449

Aging processes in precipitation-hardening composite materials based on a D16 aluminum alloy  

NASA Astrophysics Data System (ADS)

Aging of composite materials (CMs) based on an aluminum D16 alloy and reinforced by Al3Ti intermetallic inclusions (0-10 vol %) having formed upon an in situ reaction and by SiC particles (0-30 vol %) ?3 or 28 ?m in size is studied. Oxide ceramic nanoparticles (0.1 wt %) are used to modify the structure of the CMs. The structures of the CMs before and after aging are analyzed by optical microscopy and scanning electron microscopy on a microscope equipped with an X-ray energy dispersive spectrometer. The hardness of the CMs is measured. The overall hardening of aged CMs is shown to result from a competition between the hardening effects induced by the formation of Guinier-Preston zones and the precipitation of the high-temperature ? and S phases. These effects are controlled by the dislocation density in the matrix.

Chernyshova, T. A.; Kobeleva, L. I.

2010-09-01

450

Final report on LDRD project 52722 : radiation hardened optoelectronic components for space-based applications.  

SciTech Connect

This report describes the research accomplishments achieved under the LDRD Project 'Radiation Hardened Optoelectronic Components for Space-Based Applications.' The aim of this LDRD has been to investigate the radiation hardness of vertical-cavity surface-emitting lasers (VCSELs) and photodiodes by looking at both the effects of total dose and of single-event upsets on the electrical and optical characteristics of VCSELs and photodiodes. These investigations were intended to provide guidance for the eventual integration of radiation hardened VCSELs and photodiodes with rad-hard driver and receiver electronics from an external vendor for space applications. During this one-year project, we have fabricated GaAs-based VCSELs and photodiodes, investigated ionization-induced transient effects due to high-energy protons, and measured the degradation of performance from both high-energy protons and neutrons.

Hargett, Terry W. (L& M Technologies, Inc.); Serkland, Darwin Keith; Blansett, Ethan L.; Geib, Kent Martin; Sullivan, Charles Thomas; Hawkins, Samuel D.; Wrobel, Theodore Frank; Keeler, Gordon Arthur; Klem, John Frederick; Medrano, Melissa R.; Peake, Gregory Merwin; Karpen, Gary D.; Montano, Victoria A. (L& M Technologies, Inc.)

2003-12-01

451

Specific Hardening Function Definition and Characterization of a Multimechanism Generalized Potential-based Viscoelastoplasticity Model  

NASA Technical Reports Server (NTRS)

Given the previous complete-potential structure framework together with the notion of strain- and stress-partitioning in terms of separate contributions of several submechanisms (viscoelastic and viscoplastic) to the thermodynamic functions (stored energy and dissipation) a detailed viscoelastoplastic multimechanism characterization of a specific hardening functional form of the model is presented and discussed. TIMETAL 21S is the material of choice as a comprehensive test matrix, including creep, relaxation, constant strain-rate tension tests, etc. are available at various temperatures. Discussion of these correlations tests, together with comparisons to several other experimental results, are given to assess the performance and predictive capabilities of the present model particularly with regard to the notion of hardening saturation as well as the interaction of multiplicity of dissipative (reversible/irreversible) mechanisms.

Arnold, S. M.; Saleeb, A. F.

2003-01-01

452

Extraction site preservation using an in-situ hardening alloplastic bone graft substitute.  

PubMed

This case report highlights the use of an in-situ hardening alloplastic bone grafting material composed of beta-tricalcium phosphate (?-TCP) granules coated with poly(lactic-co-glycolic acid) (PLGA) to preserve the dimensions and architecture of the alveolar ridge after atraumatic extraction. This material provided a stable scaffold that, although left uncovered, deterred the ingrowth of unwanted soft tissue, allowing newly formed keratinized soft tissue to proliferate over the healing grafted socket and gradually cover the site. At re-entry after 4 months adequate newly formed bone was observed, allowing for the correct positional placement of an implant. The results of this case suggest that an in-situ hardening alloplastic grafting material can be successfully utilized with minimally invasive procedures to preserve the bone and the soft-tissue profile of the alveolar ridge for future implant rehabilitation. PMID:25455150

Leventis, Minas D; Fairbairn, Peter; Horowitz, Robert A

2014-01-01

453

Cold vs. Flu Know the Difference  

E-print Network

Cold vs. Flu Know the Difference Symptoms Cold Flu Fever Rare Usual ­ can be 100 to 102or higher can help prevent the spread of colds or flu F � KEEP YOUR HANDS CLEAN ­ Wash with soap and water. � STAY HOME WHEN SICK � GET VACCINATED FOR FLU Getting a flu shot or the nasal spray every year

Burke, Peter

454

Vitamin C and the common cold  

Microsoft Academic Search

The effect of vitamin C on the common cold has been the subject of several studies. These studies do not support a considerable decrease in the incidence of the common cold with supplemental vitamin C. However, vitamin C has consistently decreased the duration of cold episodes and the severity of symptoms. The benefits that have been observed in different studies

Harri Hemilä

1992-01-01

455

Surface hardening of metallic alloys by electrospark deposition followed by plasma nitriding  

Microsoft Academic Search

This paper presents the results of a study concerned with the surface hardening of nonferrous and ferrous alloys, by integrating the electrospark deposition and plasma nitriding processes. Specimens of an aluminium bronze and of a grey cast iron were firstly electrospark coated with AISI-304 stainless steel and, then, ion nitrided in a 25%N2+75%H2 dc plasma. It is shown that by

M. A. Béjar; W. Schnake; W. Saavedra; J. P. Vildósola

2006-01-01

456

Strain hardening in startup shear of long-chain branched polymer solutions.  

PubMed

We show for the first time that entangled polymeric liquids containing long-chain branching can exhibit strain hardening upon startup shear. As the significant long-chain branching impedes chain disentanglement, Gaussian coils between entanglements can deform to reach the finite extensibility limit where the intrachain retraction force exceeds the value expected from the usual conformational entropy loss evaluated based on Gaussian chain statistics. The phenomenon is expected to lead to further theoretical understanding. PMID:23971617

Liu, Gengxin; Cheng, Shiwang; Lee, Hyojoon; Ma, Hongwei; Xu, Hongde; Chang, Taihyun; Quirk, Roderic P; Wang, Shi-Qing

2013-08-01

457

Strain Hardening in Startup Shear of Long-Chain Branched Polymer Solutions  

NASA Astrophysics Data System (ADS)

We show for the first time that entangled polymeric liquids containing long-chain branching can exhibit strain hardening upon startup shear. As the significant long-chain branching impedes chain disentanglement, Gaussian coils between entanglements can deform to reach the finite extensibility limit where the intrachain retraction force exceeds the value expected from the usual conformational entropy loss evaluated based on Gaussian chain statistics. The phenomenon is expected to lead to further theoretical understanding.

Liu, Gengxin; Cheng, Shiwang; Lee, Hyojoon; Ma, Hongwei; Xu, Hongde; Chang, Taihyun; Quirk, Roderic P.; Wang, Shi-Qing

2013-08-01

458

Evaluation of STMicroelectronics RH-L49 1 3 positive hardened low drop voltage regulator  

NASA Astrophysics Data System (ADS)

An evaluation of the RH-L4913 from the manufacturer STMicroelectronics, total dose radiation hardened, has been done. This evaluation has consisted of an electrical characterization, a physical analysis, endurance tests (silicon & package) and radiations tests, in order to assess the specific failure modes and the reliability of this regulator in space environment. The results are presented in this paper and demonstrate the RH-L4913 regulator ability to be used in space applications.

Briand, P.; Vadrot, J.-F.; Belasic, M.

2002-12-01

459

Hardening neutron spectrum for advanced actinide transmutation experiments in the ATR.  

PubMed

The most effective method for transmuting long-lived isotopes contained in spent nuclear fuel into shorter-lived fission products is in a fast neutron spectrum reactor. In the absence of a fast test reactor in the United States, initial irradiation testing of candidate fuels can be performed in a thermal test reactor that has been modified to produce a test region with a hardened neutron spectrum. Such a test facility, with a spectrum similar but somewhat softer than that of the liquid-metal fast breeder reactor (LMFBR), has been constructed in the INEEL's Advanced Test Reactor (ATR). The radial fission power distribution of the actinide fuel pin, which is an important parameter in fission gas release modelling, needs to be accurately predicted and the hardened neutron spectrum in the ATR and the LMFBR fast neutron spectrum is compared. The comparison analyses in this study are performed using MCWO, a well-developed tool that couples the Monte Carlo transport code MCNP with the isotope depletion and build-up code ORIGEN-2. MCWO analysis yields time-dependent and neutron-spectrum-dependent minor actinide and Pu concentrations and detailed radial fission power profile calculations for a typical fast reactor (LMFBR) neutron spectrum and the hardened neutron spectrum test region in the ATR. The MCWO-calculated results indicate that the cadmium basket used in the advanced fuel test assembly in the ATR can effectively depress the linear heat generation rate in the experimental fuels and harden the neutron spectrum in the test region. PMID:16381683

Chang, G S; Ambrosek, R G

2005-01-01

460

A comparison of current work-hardening models used in the analysis of plastic deformations  

E-print Network

]ectives of Investigation. Area of Investigation. 1 2 3 II PLASTICITY. Introduction The Incremental Theory of Plasticity The Yield Criterion. The Flow Rule. The Hardening Rule Idealization of the Plastic Material 7 9 16 19 23 III METHOD OF INVESTIGATION IV... procedures. This investigation is concerned with the current capability of modeling the nonlinear behavior of structural materials used in the construction of hardware (missiles, undersea vehicles, etc. ) expected to undergo high stress loadings...

Vaughn, David Kenneth

2012-06-07

461

SEU testing of a novel hardened register implemented using standard CMOS technology  

SciTech Connect

A novel memory structure, designed to tolerate SEU perturbations, has been implemented in registers and tested. The design was completed using a standard submicron nonradiation hardened CMOS technology. This paper presents the results of heavy ions tests which evidence the noticeable improvement of the SEU-robustness with an increased LET threshold and reduced cross-section, without significant impact to die real estate, write time, or power consumption.

Monnier, T.; Roche, F.M.; Cosculluela, J.; Velazco, R.

1999-12-01

462

Solid-State Diffusion Bonding of Commercially pure Titanium and Precipitation Hardening Stainless steel  

Microsoft Academic Search

Solid-state direct diffusion bonding of commercially pure Titanium (Cp-Ti) and precipitation hardening stainless steel (PHSS) has been carried out in the temperature range of 800°C to 1000°C with an interval of 50°C for 3.6 ks under 3.5 Mpa uniaxial load in (4 to 6)×10-3 Pa vacuum. The effects of temperatures have been investigated with reference to bond strength. The examination

Debasis Poddar

463

Diffusion bonding of commercially pure titanium and 17-4 precipitation hardening stainless steel  

Microsoft Academic Search

Commercially pure titanium and 17-4 precipitation hardening stainless steel were diffusion bonded in the temperature range of 850–950°C for 7.2ks under 3.5MPa uniaxial load in vacuum. The transition joints were examined in optical and scanning electron microscope. The chemical compositions of reaction layers in the diffusion zone were determined by energy dispersive spectroscopy and the formation of intermetallics like ?

S. Kundu; M. Ghosh; S. Chatterjee

2006-01-01

464

Effect of borax on hydration and hardening properties of magnesium and pottassium phosphate cement pastes  

Microsoft Academic Search

Magnesium and potassium phosphate cement (MKPC) sample were prepared by mixing dead burnt MgO powder, potassium phosphate\\u000a and different dosages of retarder borax to investigate the effect of borax on its hydration and hardening characteristics.\\u000a The pH value, fluidity, hydration temperature and strength development of MKPC paste were investigated, and the mineralogical\\u000a composition and microstructural morphology of its hydration products

Jianming Yang; Chunxiang Qian

2010-01-01

465

Dynamics of weakly strain-hardening fluids in filament stretching devices  

Microsoft Academic Search

We investigate the transient viscoelastic response of weakly strain-hardening fluids to imposed elongational deformation in filament-stretching devices. We combine time-dependent finite-element simulations with quantitative experimental measurements on a rheologically well-characterized test fluid to investigate how well the device reproduces the ideal transient uniaxial extensional viscosity that is predicted theoretically. A concentrated polymer solution containing 5.0wt% monodisperse polystyrene is used as

Minwu Yao; Stephen H. Spiegelberg; Gareth H. McKinley

2000-01-01

466

Surface tension driven jet break up of strain-hardening polymer solutions  

Microsoft Academic Search

Experimental studies attempting to ascertain the influence of viscoelasticity on the atomization of polymer solution are often hindered by the inability to decouple the effect of shear thinning from the effect of extensional hardening. Here, the influence of viscoelasticity on the jet break up of a series of non-shear-thinning viscoelastic fluids is quantified. Previous characterization using an opposed-nozzle rheometer identified

Yenny Christanti; Lynn M. Walker

2001-01-01

467

Micropitting Damage Mechanism on Hardened and Tempered, Nitrided, and Carburizing Steels  

Microsoft Academic Search

A deep comprehension of the damage mechanisms involved in contact fatigue is basic to optimize materials and heat treatments for specific applications. In this work, rolling disc-on-disc contact fatigue tests have been performed on three different materials: a hardened and tempered UNI EN 42CrMo4, a nitrided UNI EN 42CrMo4 steel, and a carburized UNI EN 18NiCrMo5 steel. The test method

Fabrizio DE