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1

Preservation of reproductive behaviors during modest cooling: rapid cold-hardening fine-tunes organismal response  

Microsoft Academic Search

The primary objectives of this study were to determine (1) whether rapid cold-hardening (RCH) preserves reproductive behaviors during modest cooling, (2) whether increased mating success at a lower temperature comes at the cost of decreased performance at a higher temperature and (3) whether RCH is associated with an elevated metabolic rate. Drosophila melanogaster (Diptera: Drosphilidae) were rapidly cold-hardened by a

Scott M. Shreve; Jonathan D. Kelty; Richard E. Lee

2004-01-01

2

Rapid cold-hardening in larvae of the Antarctic midge Belgica antarctica: cellular cold-sensing and a role for calcium  

E-print Network

. For insects living in thermally variable environments, cold shock is a common threat that has long beenRapid cold-hardening in larvae of the Antarctic midge Belgica antarctica: cellular cold. Rapid cold-hardening in larvae of the Antarctic midge Belgica antarctica: cellular cold

Lee Jr., Richard E.

3

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

4

Cold shock injury and ecological costs of rapid cold hardening in the grain aphid Sitobion avenae (Hemiptera: Aphididae).  

PubMed

The ability of first instar nymphs and newly moulted pre-reproductive adults of the grain aphid S. avenae to rapidly cold harden was investigated. When nymphs reared at 20 degrees C were transferred directly to -8 degrees C for 3 h, there was 18% survival. This exposure was selected as the discriminating temperature. Maximum increases in survival were achieved by acclimating nymphs for 2 h at 0 degrees C and adults for 3 h at 0 degrees C, resulting in survival of 83% and 68%, respectively. Cooling nymphs from 10 to 0 degrees C at different rates (1, 0.1 and 0.05 degrees C min(-1)) also increased cold hardiness, with the slowest rate of 0.05 degrees C min(-1) conferring the highest survival following exposure to the discriminating temperature. Adult aphids also expressed a rapid cold hardening response but to a lesser extent, with survival increasing from 16% to 68% following 3 h at 0 degrees C. There were no 'ecological costs' associated with rapid cold hardening in terms of development, longevity or fecundity. The data support the hypothesis that rapid cold hardening can be induced during the cooling phase of natural diurnal temperature cycles, allowing insects to track daily changes in environmental temperatures. PMID:15081820

Powell, S J; Bale, J S

2004-04-01

5

Rapid cold-hardening increases the freezing tolerance of the Antarctic midge Belgica antarctica.  

PubMed

Rapid cold-hardening (RCH) is well known to increase the tolerance of chilling or cold shock in a diverse array of invertebrate systems at both organismal and cellular levels. Here, we report a novel role for RCH by showing that RCH also increases freezing tolerance in an Antarctic midge, Belgica antarctica (Diptera, Chironomidae). The RCH response of B. antarctica was investigated under two distinct physiological states: summer acclimatized and cold acclimated. Summer-acclimatized larvae were less cold tolerant, as indicated by low survival following exposure to -10 degrees C for 24 h; by contrast, nearly all cold-acclimated larvae survived -10 degrees C, and a significant number could survive -15 degrees C. Cold-acclimated larvae had higher supercooling points than summer larvae. To evaluate the RCH response in summer-acclimatized midges, larvae and adults, maintained at 4 degrees C, were transferred to -5 degrees C for 1 h prior to exposures to -10, -15 or -20 degrees C. RCH significantly increased survival of summer-acclimatized larvae frozen at -10 degrees C for 1 h compared with larvae receiving no cold-hardening treatment, but adults, which live for only a week or so in the austral summer, lacked the capacity for RCH. In cold-acclimated larvae, RCH significantly increased freeze tolerance to both -15 and -20 degrees C. Similarly, RCH significantly increased cellular survival of fat body, Malpighian tubules and gut tissue from cold-acclimated larvae frozen at -20 degrees C for 24 h. These results indicate that RCH not only protects against non-freezing injury but also increases freeze tolerance. PMID:16424090

Lee, Richard E; Elnitsky, Michael A; Rinehart, Joseph P; Hayward, Scott A L; Sandro, Luke H; Denlinger, David L

2006-02-01

6

The rapid cold hardening response of Drosophila melanogaster: complex regulation across different levels of biological organization.  

PubMed

Rapid cold hardening (RCH) is a form of thermal acclimation that allows ectotherms to fine-tune their physiological state to match rapid changes in thermal environment. Despite progress in recent years, there is still a considerable uncertainty regarding the physiological basis of RCH in insects. Here we investigated the physiological response of adult Drosophila melanogaster to a gradual reduction of temperature from 25 to 0°C followed by 1h at 0°C. As expected, this RCH treatment promoted cold tolerance, and so we hypothesized that this change could be detected at the proteomic level. Using 2D-DIGE, we found that only a few proteins significantly changed in abundance, and of these, we identified a set of four proteins of particular interest. These were identified as two different variants of glycogen phosphorylase (GlyP) of which three spots were up-regulated and another was down regulated. In subsequent experiments, we quantified upstream events by measuring the GlyP mRNA amount, but we found no marked effect of RCH. We also examined downstream events by measuring GlyP activity and the level of free sugars. We found no effect of RCH on GlyP activity. On the other hand, screening of whole animal sugar contents revealed a small increase in glucose levels following RCH while trehalose content was unaltered. This study highlights a complex regulation of GlyP in relation to RCH where we found associations between the cold tolerance, the protein abundance and the metabolite concentrations but no changes in mRNA expression and enzyme activity. These data stress the necessity of combining the hypothesis-generating power of an 'Omics' approach with subsequent targeted validations across several levels of the biological organization. We discuss reasons why different biological linked levels do not necessarily change stoichiometrically. PMID:24508557

Overgaard, Johannes; Sørensen, Jesper Givskov; Com, Emmanuelle; Colinet, Hervé

2014-03-01

7

Shifts in the carbohydrate, polyol, and amino acid pools during rapid cold-hardening and diapause-associated cold-hardening in flesh flies ( Sarcophaga crassipalpis ): a metabolomic comparison  

Microsoft Academic Search

Flesh flies can enhance their cold hardiness by entering a photoperiod-induced pupal diapause or by a temperature-induced\\u000a rapid cold-hardening process. To determine whether the same or different metabolites are involved in these two responses,\\u000a derivatized polar extracts from flesh flies subjected to these treatments were examined using gas chromatography–mass spectrophotometry\\u000a (GC–MS). This metabolomic approach demonstrated that levels of metabolites involved

M. Robert Michaud; David L. Denlinger

2007-01-01

8

Rapid cold-hardening in larvae of the Antarctic midge Belgica antarctica: cellular cold-sensing and a role for calcium.  

PubMed

In many insects, the rapid cold-hardening (RCH) response significantly enhances cold tolerance in minutes to hours. Larvae of the Antarctic midge, Belgica antarctica, exhibit a novel form of RCH, by which they increase their freezing tolerance. In this study, we examined whether cold-sensing and RCH in B. antarctica occur in vitro and whether calcium is required to generate RCH. As demonstrated previously, 1 h at -5 degrees C significantly increased organismal freezing tolerance at both -15 degrees C and -20 degrees C. Likewise, RCH enhanced cell survival of fat body, Malpighian tubules, and midgut tissue of larvae frozen at -20 degrees C. Furthermore, isolated tissues retained the capacity for RCH in vitro, as demonstrated with both a dye exclusion assay and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based viability assay, thus indicating that cold-sensing and RCH in B. antarctica occur at the cellular level. Interestingly, there was no difference in survival between tissues that were supercooled at -5 degrees C and those frozen at -5 degrees C, suggesting that temperature mediates the RCH response independent of the freezing of body fluids. Finally, we demonstrated that calcium is required for RCH to occur. Removing calcium from the incubating solution slightly decreased cell survival after RCH treatments, while blocking calcium with the intracellular chelator BAPTA-AM significantly reduced survival in the RCH treatments. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) also significantly reduced cell survival in the RCH treatments, thus supporting a role for calcium in RCH. This is the first report implicating calcium as an important second messenger in the RCH response. PMID:18417647

Teets, Nicholas M; Elnitsky, Michael A; Benoit, Joshua B; Lopez-Martinez, Giancarlo; Denlinger, David L; Lee, Richard E

2008-06-01

9

Rapid cold hardening increases cold and chilling tolerances more than acclimation in the adults of the sycamore lace bug, Corythucha ciliata (Say) (Hemiptera: Tingidae).  

PubMed

The sycamore lace bug, Corythucha ciliata is a new, invasive pest of Platanus trees in China. Although C. ciliata is often subjected to acute low temperatures in early winter and spring in northern and eastern China, the cold tolerance of C. ciliata has not been well studied. The objectives of this study were to determine whether adults of C. ciliata are capable of rapid cold hardening (RCH), and to compare the benefits of RCH vs. cold acclimation (ACC) in the laboratory. When the adult females incubated at 26°C were transferred directly to the discriminating temperature (-12°C) for 2 h, survival was only 22%. However, exposure to 0°C for 4 h before transfer to -12°C for 2 h induced RCH, i.e., increased survival to 68%. RCH could also be induced by gradual cooling of the insects at rates between 0.1 and 0.25°C min(-1). The protection against cold shock obtained through RCH at 0°C for 4 h was lost within 1h if the adults were returned to 26°C before exposure to -12°C. Survival at both -12 and -5°C was greater for RCH-treated than for ACC-treated adults (for ACC, adults were kept at 15°C for 5 days), and the lethal temperature (2 h exposure) was lower for RCH-treated than for ACC-treated adults. The results suggest that RCH may help C. ciliata survive the acute low temperatures that often occur in early winter and early spring in northern and eastern China. PMID:21872604

Ju, Rui-Ting; Xiao, Yu-Yu; Li, Bo

2011-11-01

10

The protective effect of rapid cold-hardening develops more quickly in frozen versus supercooled larvae of the Antarctic midge, Belgica antarctica.  

PubMed

During the austral summer, larvae of the terrestrial midge Belgica antarctica (Diptera: Chironomidae) experience highly variable and often unpredictable thermal conditions. In addition to remaining freeze tolerant year-round, larvae are capable of swiftly increasing their cold tolerance through the rapid cold-hardening (RCH) response. The present study compared the induction of RCH in frozen versus supercooled larvae. At the same induction temperature, RCH occurred more rapidly and conferred a greater level of cryoprotection in frozen versus supercooled larvae. Furthermore, RCH in frozen larvae could be induced at temperatures as low as -12°C, which is the lowest temperature reported to induce RCH. Remarkably, as little as 15 min at -5°C significantly enhanced larval cold tolerance. Not only is protection from RCH acquired swiftly, but it is also quickly lost after thawing for 2 h at 2°C. Because the primary difference between frozen and supercooled larvae is cellular dehydration caused by freeze concentration of body fluids, we also compared the effects of acclimation in dehydrated versus frozen larvae. Because slow dehydration without chilling significantly increased larval survival to a subsequent cold exposure, we hypothesize that cellular dehydration caused by freeze concentration promotes the rapid acquisition of cold tolerance in frozen larvae. PMID:23868837

Kawarasaki, Yuta; Teets, Nicholas M; Denlinger, David L; Lee, Richard E

2013-10-15

11

The limits of drought-induced rapid cold-hardening: Extremely brief, mild desiccation triggers enhanced freeze-tolerance in Eurosta solidaginis larvae.  

PubMed

Rapid cold-hardening (RCH) is a highly conserved response in insects that induces physiological changes within minutes to hours of exposure to low temperature and provides protection from chilling injury. Recently, a similar response, termed drought-induced RCH, was described following as little as 6h of desiccation, producing a loss of less than 10% of fresh mass. In this study, we investigated the limits and mechanisms of this response in larvae of the goldenrod gall fly Eurosta solidaginis (Diptera, Tephritidae). The cold-hardiness of larvae increased markedly after as few as 2h of desiccation and a loss of less than 1% fresh mass, as organismal survival increased from 8% to 41% following exposure to -18°C. Tissue-level effects of desiccation were observed within 1h, as 87% of midgut cells from desiccated larvae remained viable following freezing compared to 57% of controls. We also demonstrated that drought-induced RCH occurs independently of neuroendocrine input, as midgut tissue desiccated ex vivo displayed improved freeze-tolerance relative to control tissue (78-11% survival, respectively). Finally, though there was an increase in hemolymph osmolality beyond the expected effects of the osmo-concentration of solutes during dehydration, we determined that this increase was not due to the synthesis of glycerol, glucose, sorbitol, or trehalose. Our results indicate that E. solidaginis larvae are extremely sensitive to desiccation, which is a triggering mechanism for one or more physiological pathways that confer enhanced freeze-tolerance. PMID:25545423

Gantz, J D; Lee, Richard E

2015-02-01

12

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

13

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

14

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

15

Adaptive Changes in ATPase Activity in the Cells of Winter Wheat Seedlings during Cold Hardening  

PubMed Central

A cytochemical study of ATPase activity in the cells of cold hardened and nonhardened winter wheat (Triticum aestivum L. cv. Nongke No. 1) seedlings was carried out by electron microscopic observation of lead phosphate precipitation. ATPase activity associated with various cellular organelles was altered during cold hardening. (a) At 22°C, high plasmalemma ATPase activity was observed in both cold hardened and nonhardened tissues; at 5°C, high activity of plasmalemma ATPase was observed in hardened tissues, but not in unhardened tissues. (b) In nonhardened tissues, tonoplast and vacuoles did not exhibit high ATPase activity at either 22 or 5°C, while in hardened tissues high activity was observed at both temperatures. (c) At 5°C, ATPase activity of nucleoli and chromatin was decreased in hardened tissues, but not in nonhardened tissues. It is suggested that adaptive changes in ATPase activity associated with a particular cellular organelle or membrane may be associated with the development of frost resistance of winter wheat seedlings. Images Fig. 1 Fig. 2 Fig. 3 PMID:16662432

Jian, Ling-Cheng; Sun, Long-Hua; Dong, He-Zhu

1982-01-01

16

Changes in Hechtian Strands in Cold-Hardened Cells Measured by Optical Microsurgery1  

PubMed Central

Optical microsurgical techniques were employed to investigate the mechanical properties of Hechtian strands in tobacco (Nicotiana tabacum) and Ginkgo biloba callus cells. Using optical tweezers, a 1.5-?m diameter microsphere coated with concanavalin A was inserted though an ablated hole in the cell wall of a plasmolyzed cell and attached to a Hechtian strand. By displacing the adhered microsphere from equilibrium using the optical trapping force, the tensions of individual strands were determined. Measurements were made using both normal and cold-hardened cells, and in both cases, tensions were on the order of 10?12 N. Significant differences were found in the binding strengths of cold-hardened and normal cultured cells. An increased number density of strands in cold-hardened G. biloba compared with normal cultured cells was also observed. Although no Hechtian strands were detected in any Arabidopsis callus cells, strands were present in leaf epidermal cells. Finally, the movement of attached microspheres was monitored along the outside of a strand while cycling the osmotic pressure. PMID:10759533

Buer, Charles S.; Weathers, Pamela J.; Swartzlander, Grover A.

2000-01-01

17

Changes in Hechtian strands in cold-hardened cells measured by optical microsurgery.  

PubMed

Optical microsurgical techniques were employed to investigate the mechanical properties of Hechtian strands in tobacco (Nicotiana tabacum) and Ginkgo biloba callus cells. Using optical tweezers, a 1. 5-microm diameter microsphere coated with concanavalin A was inserted though an ablated hole in the cell wall of a plasmolyzed cell and attached to a Hechtian strand. By displacing the adhered microsphere from equilibrium using the optical trapping force, the tensions of individual strands were determined. Measurements were made using both normal and cold-hardened cells, and in both cases, tensions were on the order of 10(-12) N. Significant differences were found in the binding strengths of cold-hardened and normal cultured cells. An increased number density of strands in cold-hardened G. biloba compared with normal cultured cells was also observed. Although no Hechtian strands were detected in any Arabidopsis callus cells, strands were present in leaf epidermal cells. Finally, the movement of attached microspheres was monitored along the outside of a strand while cycling the osmotic pressure. PMID:10759533

Buer, C S; Weathers, P J; Swartzlander, G A

2000-04-01

18

Mechanism of Secondary Hardening in Rapid Tempering of Dual-Phase Steel  

NASA Astrophysics Data System (ADS)

Dual-phase steel with ferrite-martensite-bainite microstructure exhibited secondary hardening in the subcritical heat affected zone during fiber laser welding. Rapid isothermal tempering conducted in a Gleeble simulator also indicated occurrence of secondary hardening at 773 K (500 °C), as confirmed by plotting the tempered hardness against the Holloman-Jaffe parameter. Isothermally tempered specimens were characterized by analytic transmission electron microscopy and high-angle annular dark-field imaging. The cementite (Fe3C) and TiC located in the bainite phase of DP steel decomposed upon rapid tempering to form needle-shaped Mo2C (aspect ratio ranging from 10 to 25) and plate-shaped M4C3 carbides giving rise to secondary hardening. Precipitation of these thermodynamically stable and coherent carbides promoted the hardening phenomenon. However, complex carbides were only seen in the tempered bainite and were not detected in the tempered martensite. The martensite phase decomposed into ferrite and spherical Fe3C, and interlath-retained austenite decomposed into ferrite and elongated carbide.

Saha, Dulal Chandra; Nayak, Sashank S.; Biro, Elliot; Gerlich, Adrian P.; Zhou, Y.

2014-12-01

19

Effect of Cold Hardening on Sensitivity of Winter and Spring Wheat Leaves to Short-Term Photoinhibition and Recovery of Photosynthesis 1  

PubMed Central

Photoinhibition of photosynthesis and its recovery were studied in wheat (Triticum aestivum L.) leaves grown at nonhardening (20°C) and cold-hardening (5°C) temperatures. Cold-hardened wheat leaves were less susceptible to photoinhibition at 5°C than nonhardened leaves, and the winter cultivars, Kharkov and Monopol, were less susceptible than the spring cultivar, Glenlea. The presence of chloramphenicol, a chloroplastic protein synthesis inhibitor, increased the susceptibility to photoinhibition, but cold-hardened leaves still remained less susceptible to photoinhibition than nonhardened leaves. Recovery at 50 ?mol m?2 s?1 photosynthetic photon flux density and 20°C was at least biphasic, with a fast and a slow phase in all cultivars. Cold-hardened leaves recovered maximum fluorescence and maximum variable fluorescence in the dark-adapted state during the fast phase at a rate of 42% h?1 compared with 22% h?1 for nonhardened leaves. The slow phase occurred at similar rates (2% h?1) in cold-hardened and nonhardened leaves. Full recovery required up to 30 h. Fast-recovery phase was not reduced by either lowering the recovery temperature to 5°C or by the presence of chloramphenicol. Slow-recovery phase was inhibited by both treatments. Hence, the fast phase of recovery does not require de novo chloroplast protein synthesis. In addition, only approximately 60% of the photochemical efficiency lost through photoinhibition at 5°C was associated with lost [14C]atrazine binding and, hence, with damage to the secondary quinone electron acceptor for photosystem II-binding site. We conclude that the decrease in susceptibility to photoinhibition exhibited following cold hardening of winter and spring cultivars is not due to an increased capacity for repair of photoinhibitory damage at 5°C but reflects intrinsic properties of the cold-hardened photosynthetic apparatus. A model to account for the fast component of recovery is discussed. PMID:16653118

Hurry, Vaughan M.; Huner, Norman P. A.

1992-01-01

20

THE EFFECT OF AGE AND COLD HARDENING ON RESISTANCE TO PINK SNOW MOULD (MICRODOCHIUM NIVALE) IN PERENNIAL RYEGRASS (LOLIUM PERENNE L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of plant age and cold hardening on resistance to pink snow mould caused by Microdochium nivale was studied in perennial ryegrass. Resistance to M. nivale was estimated as relative regrowth after inoculation and incubation under artificial snow cover at 2ºC. Resistance increased with incre...

21

Intergranular cracking in high-strength, cold-rolled, and precipitation-hardened austenitic stainless steel UNS S35500  

SciTech Connect

When quench annealed, stainless steel UNS35500 (C 0.12, Cr 15.5, Ni 4.5, Mo 3, N O.1%) is austenitic and soft. In cold-rolled-and-tempered condition heavy cold rolling followed by precipitation hardening considerably strengthens the material (UTS 220 ksi (1517 MPa), elongation 10%). Its strength combined with good corrosion resistance make the material attractive for use in critical load-bearing applications. In one application, rotor blades of a helicopter are attached to the drive shaft with a component, strap pack, assembled from 0.014 inch (O.36 mm) thick material. Premature fatigue failures of strap packs have occurred starting from intergranular cracks in single laminae. Chloride salts were detected at crack origins. This intergranular stress corrosion cracking was reproduced under crevices in slow strain rate tests conducted in 3.5% NaCl solution at 0.1 V (Ag/AgCl 4M Kcl). The potential is typical of those attained by the material under thin, chloride-bearing condensate films exposed to air. Cracking did not occur when crevices were absent. Electrolytic polishing in chloride-free acids combined with a standard overpassivation treatment in nitric acid improved the resistance to crevice corrosion. This treatment slowed, but did not prevent, the onset of stress corrosion cracking (SCC) in slow strain rate tests conducted with an artificial crevice on the specimen surface.

Pednekar, S.P.; Champagne, V.K.; Pepi, M.S.; Grendahl, S. [Army Research Lab., Aberdeen Proving Ground, MD (United States). Weapons and Materials Directorate

1999-11-01

22

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

23

Research on rapid-cooling press hardening process and its effect for formability of ultra high strength steel  

NASA Astrophysics Data System (ADS)

In this study, a new rapid-cooling process in press hardening based on theoretical analysis, experimental test and optimal formability simulation were investigated for improving formability and obdurability of 22MnB5 boron steel. A series of non-isothermal flow behaviors in different plastic strain rates from 0.001s-1 to 0.1s-1 was investigated by thermal-mechanical uniaxial tensile tests. Furthermore, martensite transformation measurement was also involved in the temperature range from 600° to 800°. According to an interrelated Norton-Hoff constitutive model was developed to describe the complicated thermal-mechanical-phase transformation couple model, a typical deep drawing box used to simulate formability so as to compare with actual press hardening experiments used by the self-developed multi-field coupled static-explicit FE software KMAS and dynamic-explicit commercial software LS-DYNA respectively. The results showed the rapid-cooling process indicate the validity and efficiency of meeting the forming performance characteristics and the optimal process which temperature range from 650°C˜700°C can contribute to improve formability of press hardening manufacture.

Ying, L.; Hu, P.; Zhao, X.; Shi, D. Y.; Dai, M. H.; Yu, H. Y.; Chang, Y.

2013-05-01

24

Use of intraspecific variation in thermal responses for estimating an elevational cline in the timing of cold hardening in a sub-boreal conifer.  

PubMed

To avoid winter frost damage, evergreen coniferous species develop cold hardiness with suitable phenology for the local climate regime. Along the elevational gradient, a genetic cline in autumn phenology is often recognised among coniferous populations, but further quantification of evolutionary adaptation related to the local environment and its responsible signals generating the phenological variation are poorly understood. We evaluated the timing of cold hardening among populations of Abies sachalinensis, based on time series freezing tests using trees derived from four seed source populations × three planting sites. Furthermore, we constructed a model to estimate the development of hardening from field temperatures and the intraspecific variations occurring during this process. An elevational cline was detected such that high-elevation populations developed cold hardiness earlier than low-elevation populations, representing significant genetic control. Because development occurred earlier at high-elevation planting sites, the genetic trend across elevation overlapped with the environmental trend. Based on the trade-off between later hardening to lengthen the active growth period and earlier hardening to avoid frost damage, this genetic cline would be adaptive to the local climate. Our modelling approach estimated intraspecific variation in two model components: the threshold temperature, which was the criterion for determining whether the trees accumulated the thermal value, and the chilling requirement for trees to achieve adequate cold hardiness. A higher threshold temperature and a lower chilling requirement could be responsible for the earlier phenology of the high-elevation population. These thermal responses may be one of the important factors driving the elevation-dependent adaptation of A. sachalinensis. PMID:24988996

Ishizuka, W; Ono, K; Hara, T; Goto, S

2015-01-01

25

Experimental investigation of cutting tool performance in high speed cutting of hardened X210 Cr12 cold-work tool steel (62 HRC)  

Microsoft Academic Search

This study explored the performance and wear behaviour of different cutting tools in end milling of X210 Cr12 cold-work tool steel hardened to 62 HRC. The purpose of the experiments reported in this paper is to investigate the wear of TiCN coated tungsten carbide, TiCN+TiAlN coated tungsten carbide, TiAlN coated cermet, mixed ceramic with Al2O3+TiCN and cubic boron nitride (CBN)

E. Aslan

2005-01-01

26

YIELD STRENGTH PREDICTION FOR RAPID AGE-HARDENING HEAT TREATMENT OF ALUMINUM ALLOYS  

SciTech Connect

A constitutive model has been developed to predict the yield strength aging curves for aluminum casting alloys during non-isothermal age-hardening processes. The model provides the specific relationship between the process variables and yield strength. Several aging heat treatment scenarios have been investigated using the proposed model, including two-step aging recipes. Two-step aging heat treatments involve a low temperature regime to promote nucleation of secondary phases and a second step at higher temperature for the growth of the secondary phases. The predicted results show that yield strength of approximately 300MPa might be obtained in shorter aging time, of approximately 30 minutes. Thus, better mechanical properties can be obtained by optimizing the time-temperature schedules for the precipitation hardening process of heat treatable aluminum alloys.

Yin, Hebi [ORNL; Sabau, Adrian S [ORNL; Ludtka, Gerard Michael [ORNL; Skszek, Timothy [Vehma International of American, Inc.; Niu, X [Magna Cosma International, Promatek Research Centre

2013-01-01

27

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

28

Rapid Growth Reduces Cold Resistance: Evidence from Latitudinal Variation in Growth Rate, Cold Resistance and Stress Proteins  

PubMed Central

Background Physiological costs of rapid growth may contribute to the observation that organisms typically grow at submaximal rates. Although, it has been hypothesized that faster growing individuals would do worse in dealing with suboptimal temperatures, this type of cost has never been explored empirically. Furthermore, the mechanistic basis of the physiological costs of rapid growth is largely unexplored. Methodology/Principal Finding Larvae of the damselfly Ischnura elegans from two univoltine northern and two multivoltine southern populations were reared at three temperatures and after emergence given a cold shock. Cold resistance, measured by chill coma recovery times in the adult stage, was lower in the southern populations. The faster larval growth rates in the southern populations contributed to this latitudinal pattern in cold resistance. In accordance with their assumed role in cold resistance, Hsp70 levels were lower in the southern populations, and faster growing larvae had lower Hsp70 levels. Yet, individual variation in Hsp70 levels did not explain variation in cold resistance. Conclusions/Significance We provide evidence for a novel cost of rapid growth: reduced cold resistance. Our results indicate that the reduced cold resistance in southern populations of animals that change voltinism along the latitudinal gradient may not entirely be explained by thermal selection per se but also by the costs of time constraint-induced higher growth rates. This also illustrates that stressors imposed in the larval stage may carry over and shape fitness in the adult stage and highlights the importance of physiological costs in the evolution of life-histories at macro-scales. PMID:21390210

Stoks, Robby; De Block, Marjan

2011-01-01

29

Effects of bagging on volatiles and polyphenols in "Wanmi" peaches during endocarp hardening and final fruit rapid growth stages.  

PubMed

Fruits of the late-ripening peach cultivar "Wanmi" were bagged at the early period of fruit endocarp hardening, and the bags were removed 1 wk before maturity harvest. The effects of bagging on volatile compounds and polyphenols were studied. Total volatiles and the sum of C(6) compounds, esters from bagged fruits were significantly lower than from nonbagged fruits from the beginning of the final rapid fruit growth stage to maturity. As the most dominant compounds of C(6) compounds and esters, the lower contents of hexanal, trans-2-hexenal, hexyl acetate, cis-3-hexenyl acetate, and trans-2-hexenyl acetate attributed to the lower content of C(6) compounds and esters in bagged fruit. ?-Hexalactone and ?-decalactone were produced earlier in bagged fruits than in nonbagged ones, suggesting that bagging accelerates fruit maturity. Level of ?-decalactone in bagged fruits was significantly lower than in nonbagged fruits at 159 days after full blossom (DAFB), so did ?-decalactone at 166 DAFB. Bagging did not affect chlorogenic acid and catechol contents of either fruit peel or flesh, nor did it affect contents of keracyanin or quercetin-3-rutinoside in fruit flesh during fruit development. However, keracyanin and quercetin-3-rutinoside levels were significantly reduced in bagged fruit peels before ripening compared to nonbagged fruit peels. Considering the large changes in volatiles and polyphenols, the key stage for "Wanmi" fruit maturity was between 126 DAFB and 147 DAFB, about 1 mo ahead of maturity. PMID:21535618

Wang, Yiju; Yang, Chunxiang; Liu, Chunyan; Xu, Man; Li, Shaohua; Yang, Liu; Wang, Younian

2010-01-01

30

Strain induced martensite formation and its effect on strain hardening behavior in the cold drawn 304 austenitic stainless steels  

Microsoft Academic Search

SIM in the present cold drawn austenitic stainless steels, AISI 304 and AISI 304\\/Cu, nucleates mainly at the intersections of the mechanical twins rather than ?-martensite. The present results are attributed to the suppression of the formation of ?-martensite due to the increase of stacking fault energy which arise from the heat generated during high speed drawing and, for AISI

Jeom-Yong Choi; Won Jin

1997-01-01

31

7 CFR 58.641 - Hardening and storage.  

Code of Federal Regulations, 2010 CFR

...58.641 Hardening and storage. Immediately after the semifrozen product is placed in its intended...hardening tunnel or hardening room to continue the freezing process. Rapid freezing to 0° to ?15 °F is desirable to produce...

2010-01-01

32

RAPID AND SENSITIVE FAME ANALYSIS OF BACTERIA BY COLD TRAP INJECTION GAS CHROMATOGRAPHY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fatty acid analysis is commonly used to identify bacteria. A cold trap is used to focus peaks at the head of the GC column. When combined with a rapid sample processing method that uses smaller volumes of solvents, it becomes possible to correctly identify bacteria from 1-2 mg of biomass....

33

Cold plasma rapid decontamination of food contact surfaces contaminated with Salmonella biofilms  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cross-contamination of fresh produce and other foods from persistent pathogen reservoirs is a known risk factor in processing environments. Industry requires a rapid, waterless, zero-contact, chemical-free method for removing pathogens from food-contact surfaces. Cold plasma was tested for its abili...

34

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

35

Rapid remobilization of magmatic crystals kept in cold storage  

NASA Astrophysics Data System (ADS)

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.

Cooper, Kari M.; Kent, Adam J. R.

2014-02-01

36

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

37

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

38

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

39

Modelling of transformations during induction hardening and tempering  

E-print Network

There are many circumstances in industry where steel components are locally heated into the austenite phase field, and then quenched rapidly to produce a hardened region. Induction hardening is one such process used widely in the manufacture...

Gaude-Fugarolas, Daniel

40

Slow translation speed causes rapid collapse of northeast Pacific Hurricane Kenneth over cold core eddy  

NASA Astrophysics Data System (ADS)

Category 4 Hurricane Kenneth (HK) experienced unpredicted rapid weakening when it stalled over a cold core eddy (CCE) on 19-20 September 2005, 2800 km SE of Hawaii. Maximum sea surface temperature (SST) cooling of 8-9°C and a minimum aerially averaged SST of 18.3°C (over 8750 km2) characterized its cool wake. A 3-D mixed-layer model enabled estimation of enthalpy fluxes (latent and sensible heat), as well as the relative importance of slow translation speed (Uh) compared with the preexisting CCE. As Uh dropped below 1.5 m s-1, enthalpy fluxes became negative, cutting off direct ocean energy flux to HK. Although HK's weakening was attributed to wind shear, our results indicate that slow Uh and consequent intense SST cooling were the main causes. The tropical cyclone-intensified CCE experienced rapid growth in magnitude (-6 to -40 cm), increased diameter (60 to 350 km), elevated chlorophyll a for 4 months, and 12 month longevity.

Walker, Nan D.; Leben, Robert R.; Pilley, Chet T.; Shannon, Michael; Herndon, Derrick C.; Pun, Iam-Fei; Lin, I.-I.; Gentemann, Chelle L.

2014-11-01

41

PRECIPITATION HARDENING P\\/M STAINLESS STEELS  

Microsoft Academic Search

Applications requiring high strength stainless steels are growing rapidally. Precipitation- hardening stainless steels have seen limited use in powder metallurgy despite their high strength. Strengthening of these alloys is achieved by adding elements such as copper and niobium, which form intermetallic precipitates during aging. The precipitation-hardening grades exhibit corrosion resistance levels comparable with those of the chromium-nickel (300 series) grades.

Chris Schade; Pat Stears; Alan Lawley; Roger Doherty

42

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

43

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

44

Rapid toluene mineralization by aquifer microorganisms at Adak, Alaska: Implications for intrinsic bioremediation in cold environments  

USGS Publications Warehouse

Sediments from a relatively cold (5??C), petroleum hydrocarbon-contaminated aquifer in Adak, AK, mineralized [14C]toluene at an aerobic rate (16.3% day-1 at 5??C) comparable to that (5.1% day-1 at 20??C) of sediments from a more temperate aquifer at Hanahan, SC. In addition, rates of overall microbial metabolism in sediments from the two aquifers, as estimated by [1 -14C]acetate mineralization, were similar (???10.6% h-1) at their respective in situ temperatures. These results are not consistent with the common assumption that biodegradation rates in cold ground-water systems are depressed relative to more temperate systems. Furthermore, these results suggest that intrinsic bioremediation of petroleum hydrocarbon contaminants in cold groundwater systems may be technically feasible, in some cases.

Bradley, P.M.; Chapelle, F.H.

1995-01-01

45

[Rapid identification 15 effective components of anti common cold medicine with MRM by LC-MS/MS].  

PubMed

This paper reports the establishment of a method for rapid identification 15 effective components of anti common cold medicine (paracetamol, aminophenazone, pseudoephedrine hydrochloride, methylephedrine hydrochloride, caffeine, amantadine hydrochloride, phenazone, guaifenesin, chlorphenamine maleate, dextromethorphen hydrobromide, diphenhydramine hydrochloride, promethazine hydrochloride, propyphenazone, benorilate and diclofenac sodium) with MRM by LC-MS/MS. The samples were extracted by methanol and were separated from a Altantis T3 column within 15 min with a gradient of acetonitrile-ammonium acetate (containing 0.25% glacial acetic acid), a tandem quadrupole mass spectrometer equipped with electrospray ionization source (ESI) was used in positive ion mode, and multiple reaction monitoring (MRM) was performed for qualitative analysis of these compounds. The minimum detectable quantity were 0.33-2.5 microg x kg(-1) of the 15 compounds. The method is simple, accurate and with good reproducibility for rapid identification many components in the same chromatographic condition, and provides a reference for qualitative analysis illegally added chemicals in anti common cold medicine. PMID:23600148

Jiang, Jian-Guo; Zhang, Xi-Ru; Zhang, Yi-Hua; Song, Geng-Shen

2013-01-01

46

RAPID  

Cancer.gov

Rapid Access to Preventive Intervention Development (RAPID) Program About RAPID Description and Objectives of the Program Oversight RAPID Is Not... Frequently Asked Questions Application Information Format of Applications Address for Applications

47

Fatigue hardening in niobium single crystals.  

NASA Technical Reports Server (NTRS)

Nb single crystals of various orientations were cyclically deformed in tension-compression under strain control. At low strain amplitudes all crystals oriented for single slip and some oriented for multiple slip showed a two stage hardening. When present, the first stage was characterized with almost no cyclic work hardening. The rate of hardening in the second stage increased with strain amplitude and the amount of secondary slip. In crystals oriented for single slip kink bands developed on their side faces during rapid hardening stage which resulted in considerable amount of asterism in Laue spots. A cyclic stress-strain curve independent of prior history was found to exist which was also independent of crystal orientation. Furthermore, this curve differed only slightly from that of polycrystalline Nb obtained from data in literature.

Doner, M.; Diprimio, J. C.; Salkovitz, E. I.

1973-01-01

48

'Cold SSCP': a simple, rapid and non-radioactive method for optimized single-strand conformation polymorphism analyses.  

PubMed Central

A rapid (< 2.5 hrs) method for single-strand conformation polymorphism (SSCP) analysis of PCR products that allows the use of ethidium bromide staining is described. PCR products ranging in size from 117 to 256 bp were evaluated for point mutations and polymorphisms by 'cold SSCP' in commercially available pre-cast polyacrylamide mini-gels. Several electrophoretic parameters (running temperature, buffers, denaturants, DNA concentration, and gel polyacrylamide concentration) were found to influence the degree of strand separation and appeared to be PCR fragment specific. Use of the 'cold' SSCP technique and the mini-gel format allowed us to readily optimize the electrophoretic conditions for each PCR fragment. This greatly increased our ability to detect polymorphisms compared to conventional, radioisotope-labeled 'hot' SSCP, typically run under two standard temperature conditions. Excellent results have been obtained in resolving mutant PCR fragments from human p53 exons 5 through 8, human HLA-DQA, human K-ras exons 1 and 2, and rat K-ras exon 3. Polymorphisms could be detected when mutant DNA comprised as little as 3% of the total gene copies in a PCR mixture. Compared to standard 'hot' SSCP, this novel non-isotopic method has additional advantages of dramatically increased speed, precise temperature control, reproducibility, and easily and inexpensively obtainable reagents and equipment. This new method also lacks the safety and hazardous waste management concerns associated with radioactive methods. Images PMID:8367279

Hongyo, T; Buzard, G S; Calvert, R J; Weghorst, C M

1993-01-01

49

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

50

Rapid CVD growth of millimetre-sized single crystal graphene using a cold-wall reactor  

NASA Astrophysics Data System (ADS)

In this work we present a simple pathway to obtain large single-crystal graphene on copper (Cu) foils with high growth rates using a commercially available cold-wall chemical vapour deposition (CVD) reactor. We show that graphene nucleation density is drastically reduced and crystal growth is accelerated when: (i) using ex situ oxidized foils; (ii) performing annealing in an inert atmosphere prior to growth; (iii) enclosing the foils to lower the precursor impingement flux during growth. Growth rates as high as 14.7 and 17.5 ?m min?1 are obtained on flat and folded foils, respectively. Thus, single-crystal grains with lateral size of about 1 mm can be obtained in just 1 h. The samples are characterized by optical microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy as well as selected area electron diffraction and low-energy electron diffraction, which confirm the high quality and homogeneity of the films. The development of a process for the quick production of large grain graphene in a commonly used commercial CVD reactor is a significant step towards an increased accessibility to millimetre-sized graphene crystals.

Miseikis, V.; Convertino, D.; Mishra, N.; Gemmi, M.; Mashoff, T.; Heun, S.; Haghighian, N.; Bisio, F.; Canepa, M.; Piazza, V.; Coletti, C.

2015-03-01

51

Rapid Quench Cold-Seal Apparatus with Computer-Controlled Pressure and Temperature Cycling  

NASA Astrophysics Data System (ADS)

We have constructed two computer-controlled, rapid quench, hydrothermal apparatuses that are ideal for experimentation on volcanological, geothermal, and ore deposit research problems. The devices can achieve maximum pressures of about 2 kbar and temperatures to 1100C, have the ability for experiments to be quenched very rapidly in a water-cooled environment, and are interfaced with computers which can control any regimen of pressure and/or temperature cycling that may be desired, accomplished via Lab-View software and data acquisition and motion control boards from National Instruments. The rapid quench aspects of the design were developed originally by Dr. Phil Ihinger and have subsequently been adopted by many labs around the world; a good summary description of these aspects of the equipment, and the use of filler-rods for controlling redox conditions in such equipment, are provided by Matthews et al. (2004, Am. Mineral., 88: 701-707). Our design has fixed Rene 41 pressure vessels, furnaces that are raised and lowered by computer controlled pneumatic cylinders and water cooling systems that are controlled by computer operated solenoid valves. The novel feature of our design is the pressure generation and control systems. We coupled the seal-ends of commercially available (HIP) pressure generators to shop-built linear actuators consisting of nearly frictionless ball lead screws within thick walled stainless steel housings. These in turn are driven by NEMA size 23 stepper motors coupled to 100:1 gear reduction units. The actuators require 21 revolutions to achieve their full stroke of 12.7 cm which displaces about 10 cc of fluid. Operating the motors at the relatively low resolution of 800 steps per revolution leads to about 132,000 steps per cm of travel of the pressure-generating piston, providing exceptionally high precision and excellent pressure control. Instantaneous decompression can be achieved by simply opening a valve while motor-controlled decompression from 2 kbar to 1 bar can occur over time spans ranging from about one minute to months. This equipment will find immediate use in studies of decompression- induced magmatic vesiculation and crystallization in sub-volcanic and volcanic conduit environments and decompression-induced precipitation of fracture-filling ore and silicate minerals in crustal hydrothermal environments.

Johnston, A.; Senkovich, D.

2007-12-01

52

Calcium signaling mediates cold sensing in insect tissues  

PubMed Central

The ability to rapidly respond to changes in temperature is a critical adaptation for insects and other ectotherms living in thermally variable environments. In a process called rapid cold hardening (RCH), insects significantly enhance cold tolerance following brief (i.e., minutes to hours) exposure to nonlethal chilling. Although the ecological relevance of RCH is well-established, the underlying physiological mechanisms that trigger RCH are poorly understood. RCH can be elicited in isolated tissues ex vivo, suggesting cold-sensing and downstream hardening pathways are governed by brain-independent signaling mechanisms. We previously provided preliminary evidence that calcium is involved in RCH, and here we firmly establish that calcium signaling mediates cold sensing in insect tissues. In tracheal cells of the freeze-tolerant goldenrod gall fly, Eurosta solidaginis, chilling to 0 °C evoked a 40% increase in intracellular calcium concentration as determined by live-cell confocal imaging. Downstream of calcium entry, RCH conditions significantly increased the activity of calcium/calmodulin-dependent protein kinase II (CaMKII) while reducing phosphorylation of the inhibitory Thr306 residue. Pharmacological inhibitors of calcium entry, calmodulin activation, and CaMKII activity all prevented ex vivo RCH in midgut and salivary gland tissues, indicating that calcium signaling is required for RCH to occur. Similar results were obtained for a freeze-intolerant species, adults of the flesh fly, Sarcophaga bullata, suggesting that calcium-mediated cold sensing is a general feature of insects. Our results imply that insect tissues use calcium signaling to instantly detect decreases in temperature and trigger downstream cold-hardening mechanisms. PMID:23671084

Teets, Nicholas M.; Yi, Shu-Xia; Lee, Richard E.; Denlinger, David L.

2013-01-01

53

The evolution of cold tolerance in Drosophila larvae.  

PubMed

Temperature is a primary determinant of insect and other ectotherm distribution and activity. Physiological and behavioral adaptations allow many insects to survive at subzero temperatures, yet the evolutionary influences on insect cold tolerance are unclear. Supercooling points, basal cold tolerance, cold-tolerance strategy, and inducible cold tolerance from rapid cold-hardening or acclimation were measured in a phylogenetically independent context in larvae of 27 phylogenetically diverse Drosophila species acquired from stock collections. Supercooling capacity is attributed primarily to physical factors, such as dry mass and water mass. Species of the obscura group were more resistant to acute cold tolerance than species of other groups within the genus, and plasticity in cold tolerance is constrained by phylogeny rather than by basal cold tolerance. The more cold-tolerant freeze-avoiding species appear to have arisen multiple times in Drosophila and are distinct from chill-susceptible species, which likely indicate the ancestral state. A phylogenetic influence is apparent on several measures of cold tolerance, which show considerable interspecific variation and indicate varying physiological mechanisms among Drosophila species when temperature limits are met. PMID:21050129

Strachan, Lauren A; Tarnowski-Garner, Heather E; Marshall, Katie E; Sinclair, Brent J

2011-01-01

54

Cyclic cracking resistance of low-alloy and carbon structural steels hardened by tensile deformation and heat treatment  

Microsoft Academic Search

Cold drawing deformation of structural steels increases the yield limit of the material while retaining sufficiently high ductility and toughness. Consequently, in a number of cases the users of constructional rolled metal stock give preference to hardening by cold drawing in comparison with thermal hardening. This treatment is applied to, in particular, low-alloy structural steels. Taking into account the large

N. A. Umerenkova; V. T. Chernenko; A. I. Babachenko

1992-01-01

55

Mark Harden's Artchive  

NSDL National Science Digital Library

Curated by Mark Harden, the Artchive presents a useful collection of art images, text, and articles for art historians from armchair to professional levels. The Artchive itself contains some 2,300 scans of works by more than 200 artists, all accompanied by at least identifying titles, dates, artists's names, and a physical description of the original work. Harden believes that art reproductions require accompanying contextual information, and often he includes analysis and criticism by leading art historical scholars. Read Robert Hughes's short entry on the late Basquiat for a sample, or move to the Theory and Criticism section for excerpts from the canon of art history, such as E.H. Gombrich's analysis of Botticelli's Birth of Venus, or Meyer Schapiro on Cezanne. Harden employs the Web extremely effectively for presentation of art information; for example, the Schapiro Cezanne essay is divided into eight sections, each accompanied by an image of the work discussed. Other highlights of the site include Galleries, featuring changing online exhibitions; Juxtapositions, verbal/ visual commentaries on art written by Harden; and contributed reviews of commercially available art CD-ROM products.

56

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

57

Rapid decrease in cellular sodium and chloride content during cold incubation of cultured liver endothelial cells and hepatocytes.  

PubMed Central

Hypothermia, as used for organ preservation in transplantation medicine, is generally supposed to lead to an intracellular accumulation of sodium, and subsequently of chloride, via inhibition of the Na+/K+-ATPase. However, on studying the cellular sodium concentration of cultured liver endothelial cells using fluorescence microscopy, we found a 55% decrease in the cellular sodium concentration after 30 min of cold incubation in University of Wisconsin (UW) solution. To confirm this surprising result, we set up a capillary electrophoresis method that allowed us to determine the cellular contents of inorganic cations and of inorganic anions. Using this method we measured a decrease in the cellular sodium content from 104+/-11 to 55+/-4 nmol/mg of protein, accompanied by a decrease in the chloride content from 71+/-9 to 25+/-5 nmol/mg of protein, after 30 min of cold incubation in UW solution. When the endothelial cells were incubated in cold Krebs-Henseleit buffer or in cold cell culture medium instead of UW solution, similar early decreases in cellular sodium and chloride contents were observed, thus excluding the possibility of the decreases being dependent on the preservation solution used. Furthermore, experiments with cultured rat hepatocytes yielded a similar decrease in sodium content during initiation of cold incubation in UW solution, so the decrease does not appear to be cell-specific either. These results suggest that, contrary to current opinion, sodium efflux predominates over sodium influx during the early phase of cold incubation of cells. PMID:9148738

Gizewski, E R; Rauen, U; Kirsch, M; Reuters, I; Diederichs, H; Groot, H D

1997-01-01

58

Strain hardening of steel EP836  

SciTech Connect

The authors investigate the effect of different combinations of cold hydraulic pressing and heat treatment on the physical and mechanical properties of steel EP836 (03N17K10V10MT), containing 0.03% C, 16-17% Ni, 10-11.5% Co, 9.5-11.5% W, 1% Ti, 1% Mo, and 0.15% A1. Deformation of the unaged steel resulted in insignificant hardening without a decrease in plasticity; this agrees with the results of investigations of other steels of this class.

Lyadskaya, A.A.; Lappa, R.M.; Spuskanyuk, V.Z.

1986-03-01

59

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

60

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

61

Cold plasma rapid decontamination of food contact surfaces contaminated with Salmonella and Escherichia coli 0157:H7  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cross-contamination of fresh produce from persistent pathogen reservoirs is a known risk factor in processing environments. Industry requires a waterless, zero-contact, chemical-free method for removing pathogens from food-contact surfaces. Cold plasma was tested for its ability to remove biofilms f...

62

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

63

Cold stress causes rapid but differential changes in properties of plasma membrane H(+)-ATPase of camelina and rapeseed.  

PubMed

Camelina (Camelina sativa) and rapeseed (Brassica napus) are well-established oil-seed crops with great promise also for biofuels. Both are cold-tolerant, and camelina is regarded to be especially appropriate for production on marginal lands. We examined physiological and biochemical alterations in both species during cold stress treatment for 3 days and subsequent recovery at the temperature of 25°C for 0, 0.25, 0.5, 1, 2, 6, and 24h, with particular emphasis on the post-translational regulation of the plasma membrane (PM) H(+)-ATPase (EC3.6.3.14). The activity and translation of the PM H(+)-ATPase, as well as 14-3-3 proteins, increased after 3 days of cold stress in both species but recovery under normal conditions proceeded differently. The increase in H(+)-ATPase activity was the most dramatic in camelina roots after recovery for 2h at 25°C, followed by decay to background levels within 24h. In rapeseed, the change in H(+)-ATPase activity during the recovery period was less pronounced. Furthermore, H(+)-pumping increased in both species after 15min recovery, but to twice the level in camelina roots compared to rapeseed. Protein gel blot analysis with phospho-threonine anti-bodies showed that an increase in phosphorylation levels paralleled the increase in H(+)-transport rate. Thus our results suggest that cold stress and recovery in camelina and rapeseed are associated with PM H(+)-fluxes that may be regulated by specific translational and post-translational modifications. PMID:23399403

Kim, Hyun-Sung; Oh, Jung-Min; Luan, Sheng; Carlson, John E; Ahn, Sung-Ju

2013-06-15

64

Induction Hardening vs Conventional Hardening of a Heat Treatable Steel  

NASA Astrophysics Data System (ADS)

This study focuses on the comparison of mechanical and microstructural properties of induction and conventionally heat-treated steels in the as-quenched state. The investigated steel is a heat treatable 42CrMo4 steel. In order to characterize the mechanical properties, tensile tests and Vickers hardness tests are performed. The yield strength and hardness of the induction hardened condition turn out to be slightly lower compared to the conventionally hardened one. Light optical and scanning electron microscopy show no differences in the martensitic structure of the induction and conventionally hardened condition. However, electron back scatter diffraction investigations reveal a smaller block size within the conventionally hardened specimen. Carbon mappings by electron probe micro analysis show a homogenous carbon concentration in the conventionally hardened and a non-uniform distribution in the induction-hardened case. The segregation of the carbon exhibits line-type features in the induction hardened condition, lowering the total amount of carbon in the matrix. Therefore, the carbon content in the matrix of the conventionally hardened condition is slightly higher, which causes a smaller block size. The smaller block size is believed to be the reason for the higher hardness and yield strength.

Sackl, Stephanie; Leitner, Harald; Zuber, Michael; Clemens, Helmut; Primig, Sophie

2014-11-01

65

Cold-Nuclear-Matter Effects on Heavy-Quark Production at Forward and Backward Rapidity in d +Au Collisions at ?sNN =200 GeV  

NASA Astrophysics Data System (ADS)

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1rapidity (1.4<|y|<2.0) in d +Au and p+p collisions at ?sNN =200 GeV. In central d +Au collisions, relative to the yield in p+p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-pT broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d +Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.

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

2014-06-01

66

Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d + Au collisions at ?sNN = 200??GeV.  

PubMed

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 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, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter. PMID:25014805

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

2014-06-27

67

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

68

Effect of shot peening on the microstructure of laser hardened 17-4PH  

NASA Astrophysics Data System (ADS)

In order to investigate the influence of shot peening on microstructure of laser hardened steel and clarify how much influence of initial microstructure induced by laser hardening treatment on final microstructure of laser hardened steel after shot peening treatment, measurements of retained austenite, measurements of microhardness and microstructural analysis were carried out on three typical areas including laser hardened area, transitional area and matrix area of laser hardened 17-4PH steel. The results showed that shot peening was an efficient cold working method to eliminate the retained austenite on the surface of laser hardened samples. The surface hardness increased dramatically when shot peening treatments were carried out. The analyses of microstructure of laser hardened 17-4PH after shot peening treatment were carried out in matrix area and laser hardened area via Voigt method. With the increasing peening intensity, the influence depth of shot peening on hardness and microstructure increased but the surface hardness and microstructure did not change when certain peening intensity was reached. Influence depth of shot peening on hardness was larger than influence depth of shot peening on microstructure due to the kinetic energy loss along the depth during shot peening treatment. From the microstructural result, it can be shown that the shot peening treatment can influence the domain size and microstrain of treated samples but laser hardening treatment can only influence the microstrain of treated samples.

Wang, Zhou; Jiang, Chuanhai; Gan, Xiaoyan; Chen, Yanhua

2010-12-01

69

Evaluation of mini-VIDAS rapid test for detection of Listeria monocytogenes from production lines of fresh to cold-smoked fish.  

PubMed

This study was conducted to evaluate the efficacy of the mini-VIDAS Listeria monocytogenes (LMO) system (BioMérieux Vitek, Inc., Missouri, USA) for detection of L. monocytogenes in environmental and fish samples from three Portuguese cold-smoking plants and from their fresh fish suppliers. Mini-VIDAS-LMO is a fully automated system that uses fluorescent ELFA (Enzyme Linked Fluorescent Assay) technology for detection of Listeria monocytogenes antigens in food. It can be a rapid screening method alternative to time consuming classical isolation and identification. Two hundred and ninety five samples were tested in mini-VIDAS-LMO and in parallel by the ISO 11290-1 traditional protocol. The mini-VIDAS-LMO detected 8 of the 11 confirmed positive samples and presented 11 false positive results. The specificity of the mini-VIDAS-LMO found in this experiment was 0.96 and the sensitivity 0.73. PMID:10699670

Vaz-Velho, M; Duarte, G; Gibbs, P

2000-04-01

70

Cold induced changes in lipid, protein and carbohydrate levels in the tropical insect Gromphadorhina coquereliana.  

PubMed

Insects cope with thermal stressors using mechanisms such as rapid cold hardening and acclimation. These mechanisms have been studied in temperate insects, but little is known about their use by tropical insects in response to cold stress. Here, we investigated whether cold stress (1×8h and 3×8h at 4°C) triggers a metabolic response in the Madagascar cockroach Gromphadorhina coquereliana. We examined the effects of cold on the levels of selected metabolites in the fat body tissue of G. coquereliana. After cold exposure, we found that the quantity of total protein increased significantly in the insect fat body, whereas glycogen decreased slightly. Using antibodies, we observed upregulation of AQP-like proteins and changes in the HSP70 levels in the fat body of G. coquereliana when exposed to cold. We also examined the content and nature of the free sugars in the G. coquereliana hemolymph and discovered an increase in the levels of polyols and glucose in response to cold stress. These results suggest an important role of the fat body tissue of tropical insects upon cold exposure. PMID:25624163

Chowanski, Szymon; Lubawy, Jan; Spochacz, Marta; Ewelina, Paluch; Grzegorz, Smykalla; Rosinski, Grzegorz; Slocinska, Malgorzata

2015-05-01

71

System-Level Radiation Hardening  

NASA Technical Reports Server (NTRS)

Although system-level radiation hardening can enable the use of high-performance components and enhance the capabilities of a spacecraft, hardening techniques can be costly and can compromise the very performance designers sought from the high-performance components. Moreover, such techniques often result in a complicated design, especially if several complex commercial microcircuits are used, each posing its own hardening challenges. The latter risk is particularly acute for Commercial-Off-The-Shelf components since high-performance parts (e.g. double-data-rate synchronous dynamic random access memories - DDR SDRAMs) may require other high-performance commercial parts (e.g. processors) to support their operation. For these reasons, it is essential that system-level radiation hardening be a coordinated effort, from setting requirements through testing up to and including validation.

Ladbury, Ray

2014-01-01

72

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

73

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

74

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

75

Life on the Hardened Border  

ERIC Educational Resources Information Center

The many Coast Salish groups distributed on both sides of the United States-Canada border on the Pacific coast today face significant obstacles to cross the international border, and in some cases are denied passage or intimidated into not attempting to cross. The current situation regarding travel by Aboriginal people reflects the "hardening" of…

Miller, Bruce Granville

2012-01-01

76

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

77

Variable increases in cold hardiness induced in winter rape by plant growth regulators  

Microsoft Academic Search

Triazole and conventional growth regulators were tested for their ability to extend cold hardiness and improve the winter\\u000a survival of winter rape (Brassica napus L.). Winter rape plants were grown in the field (Ottawa 45°23? N) and in growth cabinets. Plant growth regulators (PGRs)\\u000a were applied during the early vegetative stage and the plants were allowed to cold harden. Cold-hardened

M. J. Morrison; C. J. Andrews

1992-01-01

78

Abstract--Several Radiation-Hardened-By-Design (RHBD) standard cells have been designed using ground  

E-print Network

ground rules for a commercial TSMC 0.3 µm CMOS technology. Post-layout simulations have been performed processes (TSMC 0.4 µm, HP 0.6 µm). These older technologies were chosen to represent the performance abandoned the rad-hard process market after the end of the cold war. Today, few radiation-hardened processes

Robinson, William H.

79

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

SciTech Connect

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, S.A.

1981-07-29

80

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

81

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

82

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

83

Cell-Wall Changes and Cell Tension in Response to Cold Acclimation and Exogenous Abscisic Acid in Leaves and Cell Cultures.  

PubMed Central

Freeze-induced cell tensions were determined by cell water relations in leaves of broadleaf evergreen species and cell cultures of grapes (Vitis spp.) and apple (Malus domestica). Cell tensions increased in response to cold acclimation in leaves of broadleaf evergreen species during extracellular freezing, indicating a higher resistance to cell volume changes during freezing in cold-hardened leaves than in unhardened leaves. Unhardened leaves, typically, did not develop tension greater than 3.67 MPa, whereas cold-hardened leaves attained tensions up to 12 MPa. With further freezing there was a rapid decline and a loss of tension in unhardened leaves of all the broadleaf evergreen species studied. Also, similar results were observed in cold-hardened leaves of all of the species except in those of inkberry (Ilex glabra) and Euonymus fortunei, in which negative pressures persisted below -40[deg]C. Abscisic acid treatment of inkberry and Euonymus kiautschovica resulted in increases in freeze-induced tensions in leaves, suggesting that both cold acclimation and abscisic acid have similar effects on freezing behavior[mdash] specifically on the ability of cell walls to undergo deformation. Decreases in peak tensions were generally associated with lethal freezing injury and may suggest cavitation of cellular water. However, in suspension-cultured cells of grapes and apple, no cell tension was observed during freezing. Cold acclimation of these cells resulted in an increase in the cell-wall strength and a decrease in the limiting cell-wall pore size from 35 to 22 A in grape cells and from 29 to 22 A in apple cells. PMID:12226314

Rajashekar, C. B.; Lafta, A.

1996-01-01

84

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 ...

85

Common cold  

MedlinePLUS

... are the most common reason that children miss school and parents miss work. Parents often get colds ... other children. A cold can spread quickly through schools or daycares. Colds can occur at any time ...

86

Radiation Hardened Electronics for Extreme 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.

Keys, Andrew S.; Watson, Michael D.

2007-01-01

87

Work Hardening and Annealing of Copper  

NSDL National Science Digital Library

This activity will demonstrate the process of work hardening and annealing of a copper. Students will get the opportunity to see the hardening of metal by deformation, experience the process of work hardening, explain the effects of work hardening in metals and experience property changes affected by annealing. This activity would be appropriate for grades 4 through high school and college level, with each age group gaining different educational benefits. Around 60 minutes is required for the demonstration. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

Stoebe, Thomas G.

88

Cold adaptations.  

PubMed

Nowdays, occupational and recreational activities in cold environments are common. Exposure to cold induces thermoregulatory responses like changes of behaviour and physiological adjustments to maintain thermal balance either by increasing metabolic heat production by shivering and/or by decreasing heat losses consecutive to peripheral cutaneous vasoconstriction. Those physiological responses present a great variability among individuals and depend mainly on biometrical characteristics, age, and general cold adaptation. During severe cold exposure, medical disorders may occur such as accidental hypothermia and/or freezing or non-freezing cold injuries. General cold adaptations have been qualitatively classified by Hammel and quantitatively by Savourey. This last classification takes into account the quantitative changes of the main cold reactions: higher or lower metabolic heat production, higher or lesser heat losses and finally the level of the core temperature observed at the end of a standardized exposure to cold. General cold adaptations observed previously in natives could also be developed in laboratory conditions by continuous or intermittent cold exposures. Beside general cold adaptation, local cold adaptation exists and is characterized by a lesser decrease of skin temperature, a more pronounced cold induced vasodilation, less pain and a higher manual dexterity. Adaptations to cold may reduce the occurrence of accidents and improve human performance as surviving in the cold. The present review describes both general and local cold adaptations in humans and how they are of interest for cold workers. PMID:19531907

Launay, Jean-Claude; Savourey, Gustave

2009-07-01

89

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

90

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

91

Combining COLD-PCR and high-resolution melt analysis for rapid detection of low-level, rifampin-resistant mutations in Mycobacterium tuberculosis.  

PubMed

Multidrug-resistant Mycobacterium tuberculosis (M. tuberculosis) remains a serious threat to public health. Mutational analysis of the gene encoding the beta subunit of RNA polymerase (rpoB) is an established and widely used surrogate marker for multidrug-resistant tuberculosis (MDR-TB). The rpoB-based drug-resistant assay requires relatively less time to detect drug resistance in M. tuberculosis, yet it fails to detect low-level mutations in wild-type DNA. Here, we describe a low-level mutation detection method that combines co-amplification at lower denaturation temperature polymerase chain reaction (COLD-PCR) with high-resolution melting (HRM) analysis, aimed at detecting low-level, rifampin-resistant mutations in M. tuberculosis. Compared to conventional polymerase chain reaction (PCR), dilution experiments demonstrated a four- to eightfold improvement in selectivity using COLD-PCR/HRM to detect low-level, rifampin-resistant mutations. The mutation detection limit of conventional PCR/HRM was approximately 20%, whereas COLD-PCR/HRM had a mutation detection limit of 2.5%. Using traditional PCR/HRM and DNA sequencing, we found rpoB mutation in 110 rifampin-resistant isolates. The use of COLD-PCR/HRM allowed us to detect 10 low-level, rifampin-resistant mutations in 16 additional drug-resistant isolates. The sensitivity of COLD-PCR/HRM (95.2%) is significantly higher than that of PCR/HRM (87.3%). Our findings demonstrate that combined use of COLD-PCR with HRM can provide a sensitivity of at least 5% in detecting rpoB-mutated populations in a wild-type background, decreasing the delay in drug-resistant TB diagnosis and leading to faster, cheaper, more efficient, and more personalized antibiotic treatment, especially for low-level drug resistance mutations among the excess wild-type DNA. PMID:23396215

Pang, Yu; Liu, Guan; Wang, Yufeng; Zheng, Suhua; Zhao, Yan-Lin

2013-04-01

92

Cold Urticaria  

Microsoft Academic Search

\\u000a Cold urticaria is a physical urticaria in which patients experience ­urticaria, angioedema, or both in response to direct\\u000a contact with cold environments, the ingestion of cold beverages or foods, and the handling of cold objects. In this chapter,\\u000a we present two challenging cases of cold urticaria that highlight the diagnostic evaluation and treatment options for these\\u000a patients.

Grace Peace Yu; Alan A. Wanderer; Massoud Mahmoudi

93

118 CASE HARDENING Routledge, London 2004  

E-print Network

Case hardening describes rocks with outer shells more resistant to erosion than interior material can act as case-hardening agents. Glazes of mostly silica and aluminum with some iron, only 20-30µm within the subsurface. Silica, aluminum, and

Dorn, Ron

94

Improved hardening theory for cyclic plasticity.  

NASA Technical Reports Server (NTRS)

A temperature-dependent version of a combined hardening theory, including isotropic and kinematic hardening, is presented within the framework of recent plasticity formulations. This theory has been found to be especially useful in finite-element analysis of aerospace vehicle engines under conditions of large plastic strain and low-cycle fatigue.

Vos, R. G.; Armstrong, W. H.

1973-01-01

95

Laser Applications in Metal Surface Hardening  

E-print Network

consumption is shown to have dropped to 0.29% of the level for the previously used hardening process. The wear and fatigue characteristics of laser-hardened surfaces are reviewed. Reference is made to the operating principles of medium to high-power carbon...

Eckersley, J. S.

1982-01-01

96

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

97

Can Winter-Active Bumblebees Survive the Cold? Assessing the Cold Tolerance of Bombus terrestris audax and the Effects of Pollen Feeding  

PubMed Central

There is now considerable evidence that climate change is disrupting the phenology of key pollinator species. The recently reported UK winter activity of the bumblebee Bombus terrestris brings a novel set of thermal challenges to bumblebee workers that would typically only be exposed to summer conditions. Here we assess the ability of workers to survive acute and chronic cold stress (via lower lethal temperatures and lower lethal times at 0°C), the capacity for rapid cold hardening (RCH) and the influence of diet (pollen versus nectar consumption) on supercooling points (SCP). Comparisons are made with chronic cold stress indices and SCPs in queen bumblebees. Results showed worker bees were able to survive acute temperatures likely to be experienced in a mild winter, with queens significantly more tolerant to chronic cold temperature stress. The first evidence of RCH in any Hymenoptera is shown. In addition, dietary manipulation indicated the consumption of pollen significantly increased SCP temperature. These results are discussed in the light of winter active bumblebees and climate change. PMID:24224036

Owen, Emily L.; Bale, Jeffrey S.; Hayward, Scott A. L.

2013-01-01

98

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

99

Rapid stalk elongation in tulip (Tulipa gesneriana L. cv. Apeldoorn) and the combined action of cold-induced invertase and the water-channel protein gammaTIP.  

PubMed

Many bulbous plants need a low-temperature treatment for flowering. Cold, for example, affects the elongation of the stalk, thereby influencing the quality of the cut flower. How the elongation of the stalk is promoted by cold and which physiological and biochemical mechanisms are involved have remained obscure. As invertase has been shown to be involved in the cold-induced elongation of the flower stalks of tulips (Lambrechts et al., 1994, Plant Physiol 104: 515-520), we further characterized this enzyme by cloning the cDNA and analysing its expression in various tissues of the tulip (Tulipa gesneriana L. cv. Apeldoorn) stalk. In addition, the role of sucrose synthase was investigated. Since turgor pressure is an important force driving cell elongation, the role of a water-channel protein (gammaTIP) was studied in relation to these two enzymes. The mRNA level of the invertase found was substantially up-regulated as a result of cold treatment. Analysis of the amino acid sequence of this invertase revealed the presence of a vacuolar targeting signal. Two different forms of sucrose synthase were found, the expression of one of them appeared to be restricted to the vascular tissue while the other form was present in the surrounding tissue. Both sucrose synthases were present in the stalk during the entire period of bulb storage and after planting, but their activities declined during stalk elongation. The expression of the gammaTIP gene was restricted mainly to the vascular tissue and its expression profile was identical to that of invertase. Simultaneous expression of invertase and gammaTIP possibly leads to an increase in osmotic potential and vacuolar water uptake, thus providing a driving force for stretching the stalk cells. PMID:10502102

Balk, P A; de Boer, A D

1999-09-01

100

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.

101

Cold Stress  

MedlinePLUS

... on frostbite and hypothermia. eLCOSH Electronic Library of Construction Occupational Safety & Health (eLCOSH) Cold stress or hypothermia can affect construction workers who are not protected against cold. The ...

102

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

103

Cyclic hardening mechanisms in Nimonic 80A  

NASA Technical Reports Server (NTRS)

A nickel base superalloy was fatigued under constant plastic strain range control. The hardening response was investigated as a function of plastic strain range and particle size of the gamma prime phase. Hardening was found to be a function of the slip band spacing. Numerous measurements of the slip band spacing and other statistical data on the slip band structures were obtained. Interactions between intersecting slip systems were shown to influence hardening. A Petch-Hall model was found to describe best this relationship between the response stress and the slip band spacing.

Lerch, B. A.; Gerold, V.

1987-01-01

104

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

105

Fructan:fructan 1-fructosyltransferase, a key enzyme for biosynthesis of graminan oligomers in hardened wheat  

Microsoft Academic Search

Fructans play important roles not only as a carbon source for survival under persistent snow cover but also as agents that protect against various stresses in overwintering plants. Complex fructans having both ß-(2,1)- and ß-(2,6)-linked fructosyl units accumulate in wheat (Triticum aestivum L.) during cold hardening. We detected fructan: fructan 1-fructosyltransferase (1-FFT; EC 2.4.1.100) activity for catalyzing the formation and

Akira Kawakami; Midori Yoshida

2005-01-01

106

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

107

Work hardening behavior in aluminum alloy 2090  

SciTech Connect

An investigation into the work hardening behavior of an aluminum alloy 2090-T81 Al-3.05Cu-2.16Li-0.12Zr at various test temperatures, heat treatment conditions and microstructures was conducted. One microstructure consisted of unrecrystallized, highly textured grains, and the other microstructure was composed of recrystallized grains. Microstructural effects on work hardening were divided into two levels of contribution: the grain structure level, which consisted of the grain size and shape, subgrains and texture, and the microconsistent level, which included the precipitates and solutes. Two heat treatments were studied: the as-received, peak-aged condition, and the solution heat treated condition where the as-received plate was resolutionized. Observations of the deformed surface of both as-received grain structures at various prestrains indicated that there was no correlation between an increase in slip homogeneity and an increase in work hardening. The increase in out-of-plane grain rotation at lower temperatures was not primarily responsible for the increase in work hardening. In addition, the fully plastic deformation microstructure for the unrecrystallized microstructure appeared very inhomogeneous as the grains deformed in bands; there were also bands of grains that had very little to no deformation. From the work hardening plots it was found that an unrecrystallized, (110)<112> textured grain structure with a homogeneous distribution of subgrains produced the highest rate of work hardening between 300 K and 77 K. When the microconstituents are added to both grain structures, both the work hardening rate in the elastic-plastic and fully plastic regimes and the level of work hardening at which the elastic-plastic to fully plastic transition occurred were affected.

Tseng, C. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1993-12-01

108

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

109

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

110

Basal cold but not heat tolerance constrains plasticity among Drosophila species (Diptera: Drosophilidae).  

PubMed

Thermal tolerance and its plasticity are important for understanding ectotherm responses to climate change. However, it is unclear whether plasticity is traded-off at the expense of basal thermal tolerance and whether plasticity is subject to phylogenetic constraints. Here, we investigated associations between basal thermal tolerance and acute plasticity thereof in laboratory-reared adult males of eighteen Drosophila species at low and high temperatures. We determined the high and low temperatures where 90% of flies are killed (ULT(90) and LLT(90) , respectively) and also the magnitude of plasticity of acute thermal pretreatments (i.e. rapid cold- and heat-hardening) using a standardized, species-specific approach for the induction of hardening responses. Regression analyses of survival variation were conducted in ordinary and phylogenetically informed approaches. Low-temperature pretreatments significantly improved LLT(90) in all species tested except for D. pseudoobscura, D. mojavensis and D. borealis. High-temperature pretreatment only significantly increased ULT(90) in D. melanogaster, D. simulans, D. pseudoobscura and D. persimilis. LLT(90) was negatively correlated with low-temperature plasticity even after phylogeny was accounted for. No correlations were found between ULT(90) and LLT(90) or between ULT(90) and rapid heat-hardening (RHH) in ordinary regression approaches. However, after phylogenetic adjustment, there was a positive correlation between ULT(90) and RHH. These results suggest a trade-off between basal low-temperature tolerance and acute low-temperature plasticity, but at high temperatures, increased basal tolerance was accompanied by increased plasticity. Furthermore, high- and low-temperature tolerances and their plasticity are clearly decoupled. These results are of broad significance to understanding how organisms respond to changes in habitat temperature and the degree to which they can adjust thermal sensitivity. PMID:21658189

Nyamukondiwa, C; Terblanche, J S; Marshall, K E; Sinclair, B J

2011-09-01

111

Cold Nuclear Matter Effects on J/? Yields as a Function of Rapidity and Nuclear Geometry in d+A Collisions at sNN=200GeV  

NASA Astrophysics Data System (ADS)

We present measurements of J/? yields in d+Au collisions at sNN=200GeV 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/? 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.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Alexander, J.; Angerami, A.; Aoki, K.; Apadula, N.; Aphecetche, L.; Aramaki, Y.; Asai, J.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Batsouli, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Belikov, S.; Belmont, R.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Bickley, A. A.; Blau, D. S.; Boissevain, J. G.; Bok, J. S.; Borel, H.; Boyle, K.; Brooks, M. L.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Camacho, C. M.; Campbell, S.; Caringi, A.; Chang, B. S.; Chang, W. C.; Charvet, J.-L.; Chen, C.-H.; Chernichenko, S.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Churyn, A.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Conesa Del Valle, Z.; Connors, M.; Constantin, P.; Csanád, M.; Csörg?, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; David, G.; Dayananda, M. K.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Dubey, A. K.; Durham, J. M.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'Yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fields, D. E.; Finger, M.; Finger, M., Jr.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Garishvili, I.; Glenn, A.; Gong, H.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gunji, T.; Gustafsson, H.-Å.; Hadj Henni, A.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Hanks, J.; Hartouni, E. P.; Haruna, K.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hohlmann, M.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imrek, J.; Inaba, M.; Isenhower, D.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Ivanischev, D.; Iwanaga, Y.; Jacak, B. V.; Jia, J.; Jiang, X.; Jin, J.; Johnson, B. M.; Jones, T.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kang, J. H.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Khanzadeev, A.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, E. J.; Kim, S. H.; Kim, Y.-J.; Kinney, E.; Kiriluk, K.; Kiss, Á.; Kistenev, E.; Klay, J.; Klein-Boesing, C.; Kochenda, L.; Komkov, B.; Konno, M.; Koster, J.; Kozlov, A.; Král, A.; Kravitz, A.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Layton, D.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Lenzi, B.; Li, X.; Lichtenwalner, P.; Liebing, P.; Linden Levy, L. A.; Liška, T.; Litvinenko, A.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mannel, E.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; Means, N.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mikeš, P.; Miki, K.; Milov, A.; Mishra, M.; Mitchell, J. T.; Mohanty, A. K.; Moon, H. J.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moukhanova, T. V.; Mukhopadhyay, D.; Murakami, T.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Newby, J.; Nguyen, M.; Nihashi, M.; Niita, T.; Nouicer, R.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Oka, M.; Okada, K.; Onuki, Y.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J.; Park, S. K.; Park, W. J.; Pate, S. F.; Pei, H.; Peng, J.-C.; Pereira, H.; Peresedov, V.; Peressounko, D. Yu.; Petti, R.; Pinkenburg, C.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reygers, K.; Riabov, V.; Riabov, Y.; Richardson, E.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rosnet, P.; Rukoyatkin, P.; Ruži?ka, P.; Rykov, V. L.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakashita, K.; Samsonov, V.; Sano, S.; Sato, T.; Sawada, S.; Sedgwick, K.; Seele, J.; Seidl, R.; Semenov, A. Yu.; Semenov, V.; Seto, R.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.

2011-09-01

112

Point defect concentrations and solid solution hardening in NiAl with Fe additions  

SciTech Connect

The solid solution hardening behavior exhibited when Fe is added to NiAl is investigated. This is an interesting problem to consider since the ternary Fe additions may choose to occupy either the Ni or the Al sublattice, affecting the hardness at differing rates. Moreover, the addition of Fe may affect the concentrations of other point defects such as vacancies and Ni anti-sites. As a result, unusual effects ranging from rapid hardening to solid solution softening are observed. Alloys with varying amounts of Fe were prepared in Ni-rich (40 at. % Al) and stoichiometric (50 at. % Al) compositions. Vacancy concentrations were measured using lattice parameter and density measurements. The site occupancy of Fe was determined using ALCHEMI. Using these two techniques the site occupancies of all species could be uniquely determined. Significant differences in the defect concentrations as well as the hardening behavior were encountered between the Ni-rich and stoichiometric regimes.

Pike, L.M.; Chang, Y.A. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; Liu, C.T. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1997-08-01

113

210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef  

NASA Astrophysics Data System (ADS)

Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr-1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr-1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth rate estimates. We show that 210Pb-226Ra dating can be successfully applied to determine the age and growth rate of framework-forming cold-water corals if Mn-Fe oxide deposits can be removed. Where metal oxides can be removed, large M. oculata and L. pertusa skeletons provide archives for studies of intermediate water masses with an up to annual time resolution and spanning over many decades.

Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

2012-03-01

114

New steels and methods for induction hardening of bearing rings and rollers  

SciTech Connect

The new method of through-surface hardening (TSH) of bearing rings and rollers was developed and used in Russia and former USSR. The principles of the method include the use of special steels of low or controlled hardenability, through-the-section induction of furnace heating and intense quenching of the parts by water stream in special devices. Due to the low hardenability of applied steels, the bearing rings and rollers have high-strength martensitic surface layer, combined with a core strengthened with a troostite and sorbite structure. High compressive residual stresses are formed in the martensitic surface layers. For a long time TSH has been successfully used for inner rings of bearings for railway car boxes, large rings and rollers of bearings for cement furnaces and rolling mills. Recently TSH was used for hollow rollers of railway bearings. For bearing rings made of SAE 52100 type high-carbon, chromium-alloyed steel a new method of low-deformation hardening was developed. The method is based on self-calibration of the rings during the quenching process and is intended for through hardening by induction heating and quenching by rapidly moved water stream.

Ouchakov, B.K.; Shepeljakovsky, K.Z. [Moscow State Evening Metallurgical Inst. (Russian Federation). Physical Metallurgy and Heat Treatment Dept.

1998-12-31

115

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

116

Centrality, Rapidity And Transverse-Momentum Dependence of Cold Nuclear Matter Effects on J/Psi Production in D Au, Cu Cu And Au Au Collisions at S(NN)**(1/2)  

SciTech Connect

We have carried out a wide study of Cold Nuclear Matter (CNM) effects on J/{Psi} = production in dAu, CuCu and AuAu collisions at {radical}s{sub NN} = 200 GeV. We have studied the effects of three different gluon-shadowing parameterizations, using the usual simplified kinematics for which the momentum of the gluon recoiling against the J/{Psi} is neglected as well as an exact kinematics for a 2 {yields} 2 process, namely g + g {yields} J/{psi} + g as expected from LO pQCD. We have shown that the rapidity distribution of the nuclear modification factor R{sub dAu}, and particularly its anti-shadowing peak, is systematically shifted toward larger rapidities in the 2 {yields} 2 kinematics, irrespective of which shadowing parameterization 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 a 2 {yields} 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.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /Ecole Polytechnique /SLAC; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay

2011-11-11

117

'Work-Hardenable' Ductile Bulk Metallic Glass  

SciTech Connect

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 of this class of metallic glass is attributed to a unique structure correlated with atomic-scale inhomogeneity, leading to an inherent capability of extensive shear band formation, interactions, and multiplication of shear bands.

Das, Jayanta; Eckert, Juergen [FG Physikalische Metallkunde, FB 11 Material- und Geowissenschaften, Technische Universitaet Darmstadt, Petersenstrasse 23, D-64287 Darmstadt (Germany); Leibniz-Institut fuer Festkoerper- und Werkstoffforschung Dresden, Institut fuer Metallische Werkstoffe, Postfach 270016, D-01171 Dresden (Germany); Tang Meibo; Wang Weihua [Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Kim, Ki Buem; Baier, Falko [FG Physikalische Metallkunde, FB 11 Material- und Geowissenschaften, Technische Universitaet Darmstadt, Petersenstrasse 23, D-64287 Darmstadt (Germany); Theissmann, Ralf [FG Strukturforschung, FB 11 Material- und Geowissenschaften, Technische Universitaet Darmstadt, Petersenstrasse 23, D-64287 Darmstadt (Germany)

2005-05-27

118

Strong Strain Hardening in Nanocrystalline Nickel  

NASA Astrophysics Data System (ADS)

Low strain hardening has hitherto been considered an intrinsic behavior for most nanocrystalline (NC) metals, due to their perceived inability to accumulate dislocations. In this Letter, we show strong strain hardening in NC nickel with a grain size of ˜20nm under large plastic strains. Contrary to common belief, we have observed significant dislocation accumulation in the grain interior. This is enabled primarily by Lomer-Cottrell locks, which pin the lock-forming dislocations and obstruct dislocation motion. These observations may help with developing strong and ductile NC metals and alloys.

Wu, X. L.; Zhu, Y. T.; Wei, Y. G.; Wei, Q.

2009-11-01

119

Thermoelastic constitutive equations for chemically hardening materials  

NASA Technical Reports Server (NTRS)

Thermoelastic constitutive equations are derived for a material undergoing solidification or hardening as the result of a chemical reaction. The derivation is based upon a two component model whose composition is determined by the degree of hardening, and makes use of strain-energy considerations. Constitutive equations take the form of stress rate-strain rate relations, in which the coefficients are time-dependent functions of the composition. Specific results are developed for the case of a material of constant bulk modulus which undergoes a transition from an initial liquidlike state into an isotropic elastic solid. Potential applications are discussed.

Shaffer, B. W.; Levitsky, M.

1974-01-01

120

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

121

Modeling cold tolerance in the mountain pine beetle, Dendroctonus ponderosae.  

PubMed

Cold-induced mortality is a key factor driving mountain pine beetle, Dendroctonus ponderosae, population dynamics. In this species, the supercooling point (SCP) is representative of mortality induced by acute cold exposure. Mountain pine beetle SCP and associated cold-induced mortality fluctuate throughout a generation, with the highest SCPs prior to and following winter. Using observed SCPs of field-collected D. ponderosae larvae throughout the developmental season and associated phloem temperatures, we developed a mechanistic model that describes the SCP distribution of a population as a function of daily changes in the temperature-dependent processes leading to gain and loss of cold tolerance. It is based on the changing proportion of individuals in three states: (1) a non cold-hardened, feeding state, (2) an intermediate state in which insects have ceased feeding, voided their gut content and eliminated as many ice-nucleating agents as possible from the body, and (3) a fully cold-hardened state where insects have accumulated a maximum concentration of cryoprotectants (e.g. glycerol). Shifts in the proportion of individuals in each state occur in response to the driving variables influencing the opposite rates of gain and loss of cold hardening. The level of cold-induced mortality predicted by the model and its relation to extreme winter temperature is in good agreement with a range of field and laboratory observations. Our model predicts that cold tolerance of D. ponderosae varies within a season, among seasons, and among geographic locations depending on local climate. This variability is an emergent property of the model, and has important implications for understanding the insect's response to seasonal fluctuations in temperature, as well as population response to climate change. Because cold-induced mortality is but one of several major influences of climate on D. ponderosae population dynamics, we suggest that this model be integrated with others simulating the insect's biology. PMID:17412358

Régnière, Jacques; Bentz, Barbara

2007-06-01

122

Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers  

SciTech Connect

The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses.

Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi'an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL

2012-01-01

123

Cold Intolerance  

MedlinePLUS

... of the brain that causes blood vessels to contract, and the hypothalmus, the part that controls the ... message to the capillaries of the skin to contract when it is cold (Bodian, 1949) . Consequently, as ...

124

Extraordinary strain hardening by gradient structure  

PubMed Central

Gradient structures have evolved over millions of years through natural selection and optimization in many biological systems such as bones and plant stems, where the structures change gradually from the surface to interior. The advantage of gradient structures is their maximization of physical and mechanical performance while minimizing material cost. Here we report that the gradient structure in engineering materials such as metals renders a unique extra strain hardening, which leads to high ductility. The grain-size gradient under uniaxial tension induces a macroscopic strain gradient and converts the applied uniaxial stress to multiaxial stresses due to the evolution of incompatible deformation along the gradient depth. Thereby the accumulation and interaction of dislocations are promoted, resulting in an extra strain hardening and an obvious strain hardening rate up-turn. Such extraordinary strain hardening, which is inherent to gradient structures and does not exist in homogeneous materials, provides a hitherto unknown strategy to develop strong and ductile materials by architecting heterogeneous nanostructures. PMID:24799688

Wu, XiaoLei; Jiang, Ping; Chen, Liu; Yuan, Fuping; Zhu, Yuntian T.

2014-01-01

125

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

126

Extraordinary strain hardening by gradient structure.  

PubMed

Gradient structures have evolved over millions of years through natural selection and optimization in many biological systems such as bones and plant stems, where the structures change gradually from the surface to interior. The advantage of gradient structures is their maximization of physical and mechanical performance while minimizing material cost. Here we report that the gradient structure in engineering materials such as metals renders a unique extra strain hardening, which leads to high ductility. The grain-size gradient under uniaxial tension induces a macroscopic strain gradient and converts the applied uniaxial stress to multiaxial stresses due to the evolution of incompatible deformation along the gradient depth. Thereby the accumulation and interaction of dislocations are promoted, resulting in an extra strain hardening and an obvious strain hardening rate up-turn. Such extraordinary strain hardening, which is inherent to gradient structures and does not exist in homogeneous materials, provides a hitherto unknown strategy to develop strong and ductile materials by architecting heterogeneous nanostructures. PMID:24799688

Wu, XiaoLei; Jiang, Ping; Chen, Liu; Yuan, Fuping; Zhu, Yuntian T

2014-05-20

127

Irradiation hardening of reduced activation martensitic steels  

NASA Astrophysics Data System (ADS)

Irradiation response on the tensile properties of 9Cr?2W steels has been investigated following FFTF/MOTA irradiations at temperatures between 646 and 873 K up to doses between 10 and 59 dpa. The largest irradiation hardening accompanied by the largest decrease in the elongation is observed for the specimens irradiated at 646 K at doses between 10 and 15 dpa. The irradiation hardening appears to saturate at a dose of around 10 dpa at the irradiation temperature. No hardening but softening was observed in the specimens irradiated at above 703 K to doses of 40 and 59 dpa. Microstructural observation by transmission electron microscope (TEM) revealed that the dislocation loops with the a<100> type Burgers vector and small precipitates which were identified to be M 6C type carbides existed after the irradiation at below 703 K. As for the void formation, the average size of voids increased with increasing irradiation temperature from 646 to 703 K. No voids were observed above 703 K. Irradiation softening was attributed to the enhanced recovery of martensitic structure under the irradiation. Post-irradiation annealing resulted in hardening by the annealing at 673 K and softening by the annealing at 873 K.

Kimura, A.; Morimura, T.; Narui, M.; Matsui, H.

1996-10-01

128

Hardenability of steels for oil industry  

Microsoft Academic Search

Purpose: Alloying elements in steels are used for a various reasons. One of the most important is the achievement of higher strength in required shapes and sizes. Often in very large sections of steels are used for production of the oil country tubular goods (OCTG). Therefore the hardenability of steels is an important property aim for the appropriate concentration of

M. Gojic; B. Kosec; I. Anzel; L. Kosec; A. Preloscan

2007-01-01

129

Plant pathology Influence of pre-hardening duration and dehardening  

E-print Network

Plant pathology Influence of pre-hardening duration and dehardening temperatures on varietal freezing resistance in faba beans ( Vicia faba L.) H. Herzog Institute of Crop Science and Plant Breeding — Hardening response of winter faba beans at 8/2°C (day/night) to pre-hardening periods at 15°C

Paris-Sud XI, Université de

130

Cold injuries.  

PubMed

Exposure to cold can produce a variety of injuries that occur as a result of man's inability to adapt to cold. These injuries can be divided into localized injury to a body part, systemic hypothermia, or a combination of both. Body temperature may fall as a result of heat loss by radiation, evaporation, conduction, and convection. Hypothermia or systemic cold injury occurs when the core body temperature has decreased to 35 degrees C (95 degrees F) or less. The causes of hypothermia are either primary or secondary. Primary, or accidental, hypothermia occurs in healthy individuals inadequately clothed and exposed to severe cooling. In secondary hypothermia, another illness predisposes the individual to accidental hypothermia. Hypothermia affects multiple organs with symptoms of hypothermia that vary according to the severity of cold injury. The diagnosis of hypothermia is easy if the patient is a mountaineer who is stranded in cold weather. However, it may be more difficult in an elderly patient who has been exposed to a cold environment. In either case, the rectal temperature should be checked with a low-reading thermometer. The general principals of prehospital management are to (1) prevent further heat loss, (2) rewarm the body core temperature in advance of the shell, and (3) avoid precipitating ventricular fibrillation. There are two general techniques of rewarming--passive and active. The mechanisms of peripheral cold injury can be divided into phenomena that affect cells and extracellular fluids (direct effects) and those that disrupt the function of the organized tissue and the integrity of the circulation (indirect effects). Generally, no serious damage is seen until tissue freezing occurs. The mildest form of peripheral cold injury is frostnip. Chilblains represent a more severe form of cold injury than frostnip and occur after exposure to nonfreezing temperatures and damp conditions. Immersion (trench) foot, a disease of the sympathetic nerves and blood vessels in the feet, is observed in shipwreck survivors or in soldiers whose feet have been wet, but not freezing, for long periods. Patients with frostbite frequently present with multisystem injuries (e.g., systemic hypothermia, blunt trauma, substance abuse). The freezing of the corneas has been reported to occur in individuals who keep their eyes open in high wind-chill situations without protective goggles (e.g., snowmobilers, cross-country skiers). PMID:15715518

Long, William B; Edlich, Richard F; Winters, Kathryne L; Britt, L D

2005-01-01

131

Cold Metal  

NSDL National Science Digital Library

In this activity, learners discover that our hands are not reliable thermometers. Learners place their palms flat on various surfaces (metal, wood, glass, etc.) and compare how cold the surfaces feel. Learners are challenged to arrange the materials in order from cold to warm. Then, they use a thermometer to measure the temperature of each surface, only to discover that the surfaces are all at the same temperature. Use this activity to talk about temperature-sensitive nerves in skin as well as how different materials act as insulators and conductors of heat.

2012-01-30

132

Radiation-hardened transistor and integrated circuit  

DOEpatents

A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.

Ma, Kwok K. (Albuquerque, NM)

2007-11-20

133

Mercury porosimetry of hardened cement pastes  

Microsoft Academic Search

Mercury porosimetry was performed on 92 hardened cement paste specimens of water\\/cement (w\\/c) ratios 0.3, 0.4, 0.5, 0.6, and 0.7 and curing times of 1, 3, 7, 14, 28, and 56 days. This paper presents the experimental techniques, results, and their possible implications with respect to pore connectivity. As expected, longer curing times and lower w\\/c ratios resulted in smaller

Raymond A. Cook; Kenneth C. Hover

1999-01-01

134

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

135

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

136

Hot, Cold, and Really Cold.  

ERIC Educational Resources Information Center

Describes a physics experiment investigating temperature prediction and the relationship between the physical properties of heat units, melting, dissolving, states of matter, and energy loss. Details the experimental setup, which requires hot and cold water, a thermometer, and ice. Notes that the experiment employs a deliberate counter-intuitive…

Leyden, Michael

1997-01-01

137

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...

138

Effect of Prior Cold Work on the Martensite Transformation in SAE 52100  

Microsoft Academic Search

Numerous publications refer to the phase transformations and properties of SAE 52100 steel, and this paper concerns itself\\u000a with the effect of prior cold deformation on the martensitic hardening response. TheA\\u000a \\u000a c1\\u000a and Ac3 temperatures are lowered due to cold work as is theM\\u000a \\u000a s\\u000a with a resultant increase in the retained austenite content for a given hardening cycle. Significantly,

J. Beswick

1984-01-01

139

Constitutive modelling of evolving flow anisotropy including distortional hardening  

SciTech Connect

The paper presents a new constitutive model for anisotropic metal plasticity that takes into account the expansion or contraction (isotropic hardening), translation (kinematic hardening) and change of shape (distortional hardening) of the yield surface. The experimentally observed region of high curvature ('nose') on the yield surface in the loading direction and flattened shape in the reverse loading direction are modelled here by means of the concept of directional distortional hardening. The modelling of directional distortional hardening is accomplished by means of an evolving fourth-order tensor. The applicability of the model is illustrated by fitting experimental subsequent yield surfaces at finite plastic deformation. Comparisons with test data for aluminium low and high work hardening alloys display a good agreement between the simulation results and the experimental data.

Pietryga, Michael P.; Vladimirov, Ivaylo N.; Reese, Stefanie [Institute of Applied Mechanics, RWTH Aachen University (Germany)

2011-05-04

140

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

141

BUSFET-a radiation-hardened SOI transistor  

Microsoft Academic Search

The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are 1) to use specially prepared SOI buried oxides that reduce the net

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

1999-01-01

142

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

143

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

144

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

145

Radiation hardening of diagnostics for fusion reactors  

SciTech Connect

A list of the diagnostic systems presently used in magnetic confinement fusion experiments is compiled herein. The radiation-sensitive components are identified, and their locations in zones around the machine are indicated. A table of radiation sensitivities of components is included to indicate the data available from previous work in fission reactor, space probe, and defense-related programs. Extrapolation and application to hardening of fusion diagnostic systems requires additional data that are more specific to the fusion radiation environment and fusion components. A list is also given of present radiation-producing facilities where near-term screening tests of materials and components can be performed.

Baur, J.F.; Engholm, B.A.; Hacker, M.P.; Maya, I.; Miller, P.H.; Toffolo, W.E.; Wojtowicz, S.S.

1981-12-01

146

Enabling Strain Hardening Simulations with Dislocation Dynamics  

SciTech Connect

Numerical algorithms for discrete dislocation dynamics simulations are investigated for the purpose of enabling strain hardening simulations of single crystals on massively parallel computers. The algorithms investigated include the /(N) calculation of forces, the equations of motion, time integration, adaptive mesh refinement, the treatment of dislocation core reactions, and the dynamic distribution of work on parallel computers. A simulation integrating all of these algorithmic elements using the Parallel Dislocation Simulator (ParaDiS) code is performed to understand their behavior in concert, and evaluate the overall numerical performance of dislocation dynamics simulations and their ability to accumulate percents of plastic strain.

Arsenlis, A; Cai, W

2006-12-20

147

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

148

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 aide 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. Details of these current technologies will be provided along with operational experience gained to date. With shuttle retirement looming, NASA has protected the capability to provide a temperature controlled environment during transportation to and from the ISS with the use of Glacier and Coldbags, which are compatible with future commercial vehicles including SpaceX's Dragon Capsule, and Orbital s Cygnus vehicle. This paper will discuss 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

2010-01-01

149

Cold Sores  

NSDL National Science Digital Library

This patient education program explains cold sores. It reviews signs, stages, infection, outbreaks, diagnosis and treatment options, as well as self-care and prevention. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

Patient Education Institute

150

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

151

Photothermal characterization of grind-hardened steel  

NASA Astrophysics Data System (ADS)

Grind hardening is a promising production process which combines grinding and hardening within one step. Due to the fact that many material and process parameters partially influence the properties of the workpieces in a nonlinear way, it is difficult to predict for instance the surface hardness and hardness penetration depth. In this study, photothermal radiometry is used as an approach to determine the hardness penetration depth. Photothermal phase signals have been measured as a function of frequency. First measurements showed a strong influence of surface roughness, causing phase signal maxima at unexpected high frequencies (f>60 Hz). After finishing of the surfaces, the maxima of phase signals shifted toward lower frequencies (f<10 Hz). In an attempt to extract a preliminary calibration curve, the measured phase values of each sample were added and correlated to the hardness penetration depth. The resulting curve reveals a good correlation between phase sum and the hardness penetration depth. Further research is necessary to collect more experimental data and to support the current results by theoretical models.

Prekel, H.; Ament, Ch.; Goch, G.

2003-01-01

152

Introduction Like their man-made counterparts, hardened biological  

E-print Network

3219 Introduction Like their man-made counterparts, hardened biological materials are tailored to perform given functions. Whether used for support (bone and cuticle), armor (shell and cuticle), or as tools (teeth and stingers), the evolution of hardened materials is driven by the need to maximize

Zok, Frank

153

High-strength age hardening coppertitanium alloys: redivivus  

E-print Network

High-strength age hardening copper­titanium alloys: redivivus W.A. Soffaa , D.E. Laughlinb by an anticipated emergence of these alloys as technologi- cally significant high-strength, high-conductivity, precipitation hardened alloys over the next decade replacing conventional Cu­Be alloys in numerous applications

Laughlin, David E.

154

A ThermoMechanical Force Model for Machining Hardened Steel  

Microsoft Academic Search

The maching of hardened steels is becoming a viable technology. At the inception of the present research, this technology for milling processes was in its infancy. Advancements in cutting tool materials such as poly-crystalline cubic boron nitride (PCBN) have enhanced the ability to machine these difficult to cut alloys. The machining of hardened tool steels have been explored in the

Charles Edward Becze

2002-01-01

155

Bulk and Surface Treatments Annealing, Normalizing, Hardening, Tempering  

E-print Network

Bulk and Surface Treatments Annealing, Normalizing, Hardening, Tempering Hardenability HEAT surface with a ductile/tough interior/bulk). The general classes of possibilities of treatment are: (i Or a combination (Thermo-mechanical, thermo-chemical) Bulk Surface #12;HEAT TREATMENTHEAT TREATMENT BULK SURFACE

Subramaniam, Anandh

156

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

157

Reduction of work hardening rate in low-carbon steels  

Microsoft Academic Search

Low carbon grades of steel rods are used to produce finished products such as fine wire, coat hangers, staples, and roofing nails. These products are subject to ductility failures during production due to excessively high work hardening rates during wire drawing. The high work hardening rates are attributed to the presence of residuals, free nitrogen, or combinations thereof. This research

Bhaskar Rao Yalamanchili

2003-01-01

158

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

159

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

160

Precipitation hardening in 350 grade maraging steel  

SciTech Connect

Evolution of microstructure in 350 grade commercial maraging steel has been examined. In the earlier stages of aging, the strengthening phases are formed by the heterogeneous precipitation, and these phases have been identified as intermetallic compounds of the Ni[sub 3] (Ti, Mo) and Fe[sub 2]Mo types. The kinetics of precipitation are studied in terms of the activation energy by carrying out isothermal hardness measurements of aged material. The mechanical properties in the peak-aged and overaged conditions were evaluated and the flow behavior examined. The overaging behavior of the steel has been studied and the formation of austenite of different morphologies identified. The crystallography of the austenite has been examined in detail. From the microstructural examination of peak-aged and deformed samples, it could be inferred that the dislocation-precipitate interaction is by precipitate shearing. Increased work hardening of the material in the overaged condition was suggestive of looping of precipitates by dislocations.

Viswanathan, U.K. (Bhabha Atomic Research Centre, Bombay, (India). Radiometallurgy Div.); Dey, G.K. (Bhabha Atomic Research Centre, Bombay, (India). Metallurgy Division); Asundi, M.K. (Government Colony, Bombay, (India))

1993-11-01

161

Superfunctionalities in Nanodispersive Precipitation-Hardened Alloys  

NASA Astrophysics Data System (ADS)

Although nanodispersive precipitation-hardened alloys have been intensively studied over decades as important structural materials, the possibility that these alloys may have superfunctional properties has been completely overlooked. As shown in this Letter, they may have giant low-hysteretic strain responses to external stimuli if the nanosized single-domain precipitates can switch their orientation variants under applied fields. We demonstrate that the misfit-generated coherency stress can significantly reduce the variant switching barriers and may drastically decrease or even eliminate the hysteresis of the strain super responses to external stress and/or magnetic fields. These alloys can thus be functionalized as shape memory, superelastic, and/or supermagnetostrictive materials. The conditions of such functionalization are established by the interpretation-transparent analytical calculations, and confirmed by computer prototyping. In particular, the obtained results pave the way for the engineering of rare-earth free alloys with excellent magnetomechanical and good mechanical properties.

Rao, Wei-Feng; Khachaturyan, Armen G.

2012-09-01

162

Dilatant hardening of fluid-saturated sandstone  

NASA Astrophysics Data System (ADS)

The presence of pore fluid in rock affects both the elastic and inelastic deformation processes, yet laboratory testing is typically performed on dry material even though in situ the rock is often saturated. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained, undrained, and unjacketed response. Confined compression experiments, both conventional triaxial and plane strain, were performed on water-saturated Berea sandstone to investigate poroelastic and inelastic behavior. Measured drained response was used to calibrate an elasto-plastic constitutive model that predicts undrained inelastic deformation. The experimental data show good agreement with the model: dilatant hardening in undrained triaxial and plane strain compression tests under constant mean stress was predicted and observed.

Makhnenko, Roman Y.; Labuz, Joseph F.

2015-02-01

163

The combination of precipitation and dispersion hardening in powder metallurgy produced Cu-Ti-Si alloy  

SciTech Connect

Microstructure and microhardness properties of precipitation hardened Cu-Ti and precipitation/dispersion hardened Cu-Ti-Si alloys have been analyzed. Cu-1.2Ti and Cu-1.2Ti-3TiSi{sub 2} (wt.%) atomized powders were characterized before and after consolidation by HIP (Hot Isostatic Pressing). Rapidly solidified powders and HIP-ed compacts were subsequently subjected to thermal treatment in hydrogen at temperatures between 300 and 600 deg. C. Compared to Cu-Ti powder particles and compacts, obtained by the same procedure, the strengthening effect in Cu-1.2Ti-3TiSi{sub 2} powder particles and compacts was much greater. The binary and ternary powders both reveal properties superior to those of Cu-1.2Ti and Cu-1.2Ti-3TiSi{sub 2} compacts. Microhardness analysis as a function of the aging temperature of Cu-1.2Ti-3TiSi{sub 2} alloy shows an interaction between precipitation and dispersion hardening which offers possibilities for an application at elevated temperatures.

Bozic, D. [Institute of Nuclear Sciences 'Vinca', P.O.Box 522, 11001 Belgrade (Serbia); Dimcic, O. [TCF, Bulevar Mihajla Pupina 176, 11070 Belgrade (Serbia); Dimcic, B. [Institute of Nuclear Sciences 'Vinca', P.O.Box 522, 11001 Belgrade (Serbia)], E-mail: bidim@vin.bg.ac.yu; Cvijovic, I.; Rajkovic, V. [Institute of Nuclear Sciences 'Vinca', P.O.Box 522, 11001 Belgrade (Serbia)

2008-08-15

164

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 ...

165

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 ...

166

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

167

Porosity and mechanically optimized PLGA based in situ hardening systems.  

PubMed

Goal of the present study was to develop and to characterize in situ-hardening, porous PLGA-based systems for their future application as bone grafting materials. Therefore, we investigated the precipitation behavior of formulations containing PLGA and a water-miscible solvent, DMSO, PEG 400, and NMP. To increase porosity, a pore forming agent (NaCMC) was added and to enhance mechanical properties of the system, an inorganic filler (?-TCP) was incorporated. The behavior upon contact with water and the influence of the prior addition of aqueous media on the morphology of the corresponding hardened implants were investigated. We proved cell-compatibility by live/dead assays for the hardened porous polymer/ceramic-composite scaffolds. The IsHS formulations can therefore be used to manufacture hardened scaffolds ex vivo by using molds with the desired shape and size. Cells were further successfully incorporated into the IsHS by precultivating the cells on the ?-TCP-powder prior to their admixing to the formulation. However, cell viability could not be maintained due to toxicity of the tested solvents. But, the results demonstrate that in vivo cells should well penetrate, adhere, and proliferate in the hardened scaffolds. Consequently, we consider the in situ hardening system being an excellent candidate as a filling material for non-weight-bearing orthopedic indications, as the resulting properties of the hardened implant fulfill indication-specific needs like mechanical stability, elasticity, and porosity. PMID:22947486

Schloegl, W; Marschall, V; Witting, M Y; Volkmer, E; Drosse, I; Leicht, U; Schieker, M; Wiggenhorn, M; Schaubhut, F; Zahler, S; Friess, W

2012-11-01

168

Effect of low-temperature hardening on activities of proteolytic enzymes and their inhibitors in the leaves of wheat and cucumber seedlings  

Microsoft Academic Search

On seedlings of winter wheat (Triticum aestivum L.) and cucumber (Cucumis sativus L.), the dynamics of cysteine and serine trypsin-like proteinases and also trypsin inhibitors at cold hardening (5°C for\\u000a wheat and 10°C for cucumber) was studied. Activation of proteinases and inhibitors coincided in time or preceded an increased\\u000a tolerance in wheat and cucumber seedlings in the early period of

S. A. Frolova; A. F. Titov; V. V. Talanova

2011-01-01

169

Zinc coated sheet steel for press hardening  

NASA Astrophysics Data System (ADS)

Galvanized steels are of interest to enhance corrosion resistance of press-hardened steels, but concerns related to liquid metal embrittlement have been raised. The objective of this study was to assess the soak time and temperature conditions relevant to the hot-stamping process during which Zn penetration did or did not occur in galvanized 22MnB5 press-hardening steel. A GleebleRTM 3500 was used to heat treat samples using hold times and temperatures similar to those used in industrial hot-stamping. Deformation at both elevated temperature and room temperature were conducted to assess the coating and substrate behavior related to forming (at high temperature) and service (at room temperature). The extent of alloying between the coating and substrate was assessed on undeformed samples heat treated under similar conditions to the deformed samples. The coating transitioned from an ? + Gamma1 composition to an ? (bcc Fe-Zn) phase with increased soak time. This transition likely corresponded to a decrease in availability of Zn-rich liquid in the coating during elevated temperature deformation. Penetration of Zn into the substrate sheet in the undeformed condition was not observed for any of the processing conditions examined. The number and depth of cracks in the coating and substrate steel was also measured in the hot-ductility samples. The number of cracks appeared to increase, while the depth of cracks appeared to decrease, with increasing soak time and increasing soak temperature. The crack depth appeared to be minimized in the sample soaked at the highest soak temperature (900 °C) for intermediate and extended soak times (300 s or 600 s). Zn penetration into the substrate steel was observed in the hot-ductility samples soaked at each hold temperature for the shortest soak time (10 s) before being deformed at elevated temperature. Reduction of area and elongation measurements showed that the coated sample soaked at the highest temperature and longest soak time maintained the highest ductility when compared to the uncoated sample processed under the sample conditions. Fractography of the hot-ductility samples showed features associated with increased ductility with increased soak time for all soak temperatures. Heat treatments (without elevated temperature deformation) and subsequent room temperature deformation were conducted to investigate the "in-service" behavior of 22MnB5. The uncoated and coated specimens deformed at room temperature showed similar ultimate tensile strength and ductility values. The only notable differences in the room temperature mechanical behavior of uncoated and coated samples processed under the same conditions were a result of differences in the substrate microstructure. All samples appeared to have ductile fracture features; features characteristic of liquid metal embrittlement were not observed.

Ghanbari, Zahra N.

170

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

171

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

172

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

173

7 CFR 58.622 - Hardening and storage rooms.  

Code of Federal Regulations, 2010 CFR

...and storage rooms. Hardening and storage rooms for frozen desserts shall be constructed of satisfactory material for...way should be provided to minimize heat shock of the frozen products. Equipment and...

2010-01-01

174

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

175

Beam Hardening Corrections in Quantitative Computed Tomography  

SciTech Connect

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 [John F. Welch Technology Centre, GE Global Research Centre, Bangalore, (India)

2007-03-21

176

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

177

Radiation-hardened bulk Si-gate CMOS microprocessor family  

Microsoft Academic Search

RCA and Sandia Laboratories jointly developed a radiation-hardened bulk Si-gate CMOS technology which is used to fabricate the CDP-1800 series microprocessor family. Total dose hardness of 1 x 10 rads (Si) and transient upset hardness of 5 x 10 rads (Si)\\/sec with no latch up at any transient level was achieved. Radiation-hardened parts manufactured to date include the CDP-1802 microprocessor,

R. E. Stricker; A. G. F. Dingwall; S. Cohen; J. R. Adams; W. C. Slemmer

1979-01-01

178

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

179

Effect of heat treatment on strain hardening of ZK60 Mg alloy  

Microsoft Academic Search

Strain hardening behaviors of extruded ZK60 Mg alloy under different heat treatments (T4, T5 and T6) were studied using uniaxial tensile tests at room temperature. Hardening capacity, strain hardening exponent as well as strain hardening rate curve were obtained according to true plastic stress–strain curves. T5 and T6 treatments decrease strain hardening of extruded ZK60 alloy, and subsequently give rise

Xianhua Chen; Fusheng Pan; Jianjun Mao; Jingfeng Wang; Dingfei Zhang; Aitao Tang; Jian Peng

2011-01-01

180

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

181

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

182

Hardening Techniques: Achieved through the application of geosythetics and gravel. Hardening techniques provide a long-term solution to withstand high use intensity and require minimal maintenance.  

E-print Network

Hardening Techniques: Achieved through the application of geosythetics and gravel. Hardening. Addition of gravel to hold structure in place and provide a hard, armored surface to the trail. 4. Top view of trail hardening techniques with geoweb showing through the gravel. Enhancing the Sustainability

Bolding, M. Chad

183

RAPID Contacts  

Cancer.gov

Rapid Access to Preventive Intervention Development (RAPID) Program Contacts Program Contact RAPID ProgramAttn: Izet M. Kapetanovic, PhD, Program Director Chemopreventive Agent Development Research Group Division of Cancer Prevention, NCI Executive Plaza

184

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

185

Process design of press hardening with gradient material property influence  

NASA Astrophysics Data System (ADS)

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.; Schieck, F.; Rautenstrauch, A.

2011-05-01

186

Changes in Hechtian Strands in Cold-Hardened Cells Measured by Optical Microsurgery1  

E-print Network

plasmolysis of plant cells, it is often possible to detect thread-like strands connecting the cell wall et al., 1994; Bachewich and Heath, 1997) and the length varies with the degree of plasmolysis during plasmolysis. Using a fractal analysis with a time-dependent fractal dimension, they showed

Swartzlander Jr., Grover A.

187

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

188

Two simple and rapid methods for the detection of polymer-degrading enzymes on high-resolution, alkaline, cold, in situ-native (HiRACIN)PAGE and high-resolution, in situ-inhibited native (HiRISIN)PAGE  

Microsoft Academic Search

Two sensitive, high-resolution and exceedingly versatile methods for the detection of isoenzymes of polymer-degrading enzymes on high-resolution, alkaline, cold, in situ-native (HiRACIN)-PAGE and high-resolution in situ-inhibited, native (HiRISIN)-PAGE are described. Extracellular crude extracts containing xylanases and carboxymethylcellulases from Scopulariopsis sp. and glucoamylases from Aspergillus niger were subjected to non-denaturing PAGE containing substrates in the resolving gel. In case of HiRACIN-PAGE, the enzymes

Ahmed Jawaad Afzal; Salim Ahmed Bokhari; Waseem Ahmad; Mohammad Hamid Rashid; Mohammad Ibrahim Rajoka; Khawar Sohail Siddiqui

2000-01-01

189

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

190

Anisotropic hardening model based on non-associated flow rule and combined nonlinear kinematic hardening for sheet materials  

NASA Astrophysics Data System (ADS)

A material model for more effective analysis of plastic deformation of sheet materials is presented in this paper. The model is capable of considering the following aspects of plastic deformation behavior of sheet materials: the anisotropy in yielding stresses in different directions by using a quadratic yield function (based on Hill's 1948 model and stress ratios), the anisotropy in work hardening by introducing non-constant flow stress hardening in different directions, the anisotropy in plastic strains in different directions by using a quadratic plastic potential function and non-associated flow rule (based on Hill's 1948 model and plastic strain ratios, r-values), and finally some of the cyclic hardening phenomena such as Bauschinger's effect and transient behavior for reverse loading by using a coupled nonlinear kinematic hardening (so-called Armstrong-Frederick-Chaboche model). Basic fundamentals of the plasticity of the model are presented in a general framework. Then, the model adjustment procedure is derived for the plasticity formulations. Also, a generic numerical stress integration procedure is developed based on backward-Euler method (so-called multi-stage return mapping algorithm). Different aspects of the model are verified for DP600 steel sheet. Results show that the new model is able to predict the sheet material behavior in both anisotropic hardening and cyclic hardening regimes more accurately. By featuring the above-mentioned facts in the presented constitutive model, it is expected that more accurate results can be obtained by implementing this model in computational simulations of sheet material forming processes. For instance, more precise results of springback prediction of the parts formed from highly anisotropic hardened materials or that of determining the forming limit diagrams is highly expected by using the developed material model.

Taherizadeh, Aboozar; Green, Daniel E.; Yoon, Jeong W.

2013-12-01

191

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): ...

192

Cold and Cough Medicines  

MedlinePLUS

... What can you do for your cold or cough symptoms? Besides drinking plenty of fluids and getting ... medicines. There are lots of different cold and cough medicines, and they do different things. Nasal decongestants - ...

193

Solute hardening and softening effects in B2 nickel aluminides  

SciTech Connect

The effect of substitutional solute additions including Fe, Mn, and Pd on the hardness of B2-ordered NiAl alloys was investigated. The solid solution hardening behavior of intermetallics is more complex than that of typical metallic solid solutions because of complications arising from the site preference of the solute as well as the effects of the solute on the concentrations of other point defects, e.g., vacancies and anti-site defects. For this reason, care was taken to experimentally establish solute site preferences and point defect concentrations in the NiAl alloys before analyzing the hardness data. By taking these factors into account it was possible to rationalize the observed unusual hardening effects. Three distinct categories of solid solution hardening behavior were encountered. The first was hardening by the solute addition itself. This was observed in the case of Pd additions to Al-poor NiAl. However, when fe or Mn is added to Al-poor NiAl a second category is observed; these elements are seen to soften the material. The third category of behavior is observed when Fe is added to NiAl with a constant Al concentration of 50 at. %. In this case it is vacancies, rather than solute atoms, which harden the material.

Pike, L.M.; Liu, C.T.; Anderson, I.M. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Chang, Y.A. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

1998-11-01

194

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

195

The Effects of Cold Acclimation of Winter Wheat Plants on Changes in CO 2 Exchange and Phenolic Compound Formation  

Microsoft Academic Search

We studied CO2 exchange and phenolic compound production in various organs of unhardened and hardened winter wheat (Triticum aestivum L.) plants. The rates of CO2 assimilation at saturating illumination (photosynthesis) and CO2 evolution in darkness (respiration) declined substantially at the autumnal decrease of ambient temperature. However, because of a higher cold resistance of photosynthesis, the ratio of photosynthesis to respiration

N. V. Zagoskina; N. A. Olenichenko; S. V. Klimov; N. V. Astakhova; E. A. Zhivukhina; T. I. Trunova

2005-01-01

196

Research on the influence of material properties on cold ring rolling processes by 3D-FE numerical simulation  

Microsoft Academic Search

During cold ring rolling processes, the material properties of the ring blank have a significant effect on the quality of the deformed ring and the determination of forming parameters. In this paper, the coupled influence laws of material properties parameters (hardening exponent n, yield stress ?s and elastic modulus E) and forming parameters (rotational speed n1 of driver roll and

He Yang; Lianggang Guo; Mei Zhan; Zhichao Sun

2006-01-01

197

Post Treatment Laser Irradiation For Recovery Of Deformation Induced By Surface Laser Hardening  

NASA Astrophysics Data System (ADS)

In order to improve the wear resistance of parts without affecting the softer, tough interior of the part, laser hardening offers many advantages. Compared to conventional processes, only a shallow layer of the metal part is heated by laser irradiation to just below the melting temperature, while the surrounding material remains at ambient temperature. Due to heat conduction into the bulk material, the surface will cool down as soon as the laser beam moves away. This self-quenching creates a particularly fine-grained martensitic micro structure with high hardness without causing fragileness of the base material. Notably lower distortions of parts avoiding costly rework are produced due to laser beam follows the contours precisely. Nevertheless, when part is thin and slim even the low distortion caused by the laser hardening can deeply affects the part ability to function fairly. In this paper a double treatment is proposed in order to recover the bending and bulging deformation induced by the thermal cycle and phase transformation. Both the numerical and experimental approaches were used in a synergic attempt to rapidly achieve the goal of minimizing the displacements to a steel laser-hardened edge of a thin blade for fibers cutting application. The modeling parameters comprise geometries, laser characters, material properties and mechanical properties; the model was built by means of the finite element method. In order to validate the numerical model the experimental and numerical outputs were crosschecked. The numerical model built up for this demonstration is able to extend its predicting ability to a vast range of similar applications.

Casalino, Giuseppe; Giorleo, Luca; Capello, Edoardo

2009-11-01

198

Exercising in Cold Weather  

MedlinePLUS

... www.nia.nih.gov/Go4Life Exercising in Cold Weather Exercise has benefits all year, even during winter. ... activities when it’s cold outside: l Check the weather forecast. If it’s very windy or cold, exercise ...

199

Hypothermia: A Cold Weather Hazard  

MedlinePLUS

... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ... cold it is where you are. Check the weather forecasts for windy and cold weather. Try to ...

200

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

201

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

202

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

203

Laser hardening techniques on steam turbine blade and application  

NASA Astrophysics Data System (ADS)

Different laser surface hardening techniques, such as laser alloying and laser solution strengthening were adopted to perform modification treatment on the local region of inset edge for 2Cr13 and 17-4PH steam turbine blades to prolong the life of the blades. The microstructures, microhardness and anti-cavitation properties were investigated on the blades after laser treatment. The hardening mechanism and technique adaptability were researched. Large scale installation practices confirmed that the laser surface modification techniques are safe and reliable, which can improve the properties of blades greatly with advantages of high automation, high quality, little distortion and simple procedure.

Yao, Jianhua; Zhang, Qunli; Kong, Fanzhi; Ding, Qingming

204

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

205

Risk Analysis and Probabilistic Survivability Assessment (RAPSA): An Assessment Approach for Power Substation Hardening1  

E-print Network

Substation Hardening1 Carol Taylor, Axel Krings and Jim Alves-Foss Computer Science Department University is currently being developed for power industry cyber security assessment and hardening. A substation example

Krings, Axel W.

206

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  

E-print Network

We present measurements of J/psi yields in d+Au collisions at sqrt(s_NN) = 200 GeV recorded by the PHENIX experiment and compare 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 (-2.2 < y < 2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. To remove model dependent systematic uncertainties we also compare the data to a simple geometric model. We find that calculations where the nuclear modification is linear or exponential in the density weighted longitudinal thickness are difficult to reconcile with the forward rapidity data.

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. Bathe; 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. Csörg\\Ho; 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; \\, Jr.; 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; E. 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; D. P. Morrison; 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; J. 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

2010-10-06

207

Cold Nuclear Matter Effects on J\\/psi Yields as a Function of Rapidity and Nuclear Geometry in d+A Collisions at sNN=200GeV  

Microsoft Academic Search

We present measurements of J\\/psi yields in d+Au collisions at sNN=200GeV 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 (-2.2

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. Bathe; 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. Csörgo; 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; O. Drapier; A. Drees; K. A. Drees; A. K. Dubey; J. M. Durham; A. Durum; D. Dutta; V. Dzhordzhadze; L. D'Orazio; 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; M. Finger Jr.; 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; R. Han; J. Hanks; E. P. Hartouni; K. Haruna; E. Haslum; R. Hayano; X. He; M. Heffner; T. K. Hemmick; T. Hester; 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. 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; X. Li; P. Lichtenwalner; P. Liebing; L. A. Linden Levy; T. Liska; A. Litvinenko; H. Liu; M. X. Liu; B. Love; D. Lynch; C. F. Maguire; Y. I. Makdisi; A. Malakhov; M. D. Malik; V. I. Manko; E. Mannel; Y. Mao; L. Masek; H. Masui; F. Matathias; M. McCumber; P. L. McGaughey; D. McGlinchey; N. Means; B. Meredith; Y. Miake; T. Mibe; A. C. Mignerey; P. Mikes; K. Miki; A. Milov; M. Mishra; J. T. Mitchell; A. K. Mohanty; H. J. Moon; Y. Morino; A. Morreale; D. P. Morrison; 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; M. Oka; K. Okada; 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. Ruzicka; 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. Slunecka; 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

2011-01-01

208

About RAPID  

Cancer.gov

The Rapid Access to Preventive Intervention Development (RAPID) Program makes the contract resources from NCI's Division of Cancer Prevention available to academic and academically-affiliated investigators for preclinical and early clinical drug development.

209

Solid-solution hardening of a high-Entropy AlTiVCrNbMo alloy  

NASA Astrophysics Data System (ADS)

The nature of solid-solution hardening of high-entropy alloys is discussed using an equiatomic bcc AlTiVCrNbMo alloy as an example. The hardening of the alloy is found to be characterized by an increase in the temperature dependence of the component of the critical shear strength and by anomalously high athermic hardening due to the perpendicular slip plane of the Burgers vector component. A relatively simple expression is proposed to estimate the detected hardening ? H(??).

Firstov, S. A.; Rogul', T. G.; Krapivka, N. A.; Ponomarev, S. S.; Tkach, V. N.; Kovylyaev, V. V.; Gorban', V. F.; Karpets, M. V.

2014-04-01

210

A new hardening function for bounding surface plasticity to predict soil behavior in overall strain ranges  

Microsoft Academic Search

An elasto-plastic constitutive model based on an anisotropic hardening rule was proposed to model the stress-strain behavior\\u000a from small to large strains. The anisotropic hardening rule was based on the generalization of isotropic hardening rule and\\u000a included a simple hardening function with respect to a unique internal variable. However plasticity in reverse loading condition\\u000a could be modeled by discrete formation

Seboong Oh

2007-01-01

211

Hot Machining of Hardened Steels with Coated Carbide Inserts  

Microsoft Academic Search

Problem statement: The benefits of easier manufacture of hardened ste el components can be substantial in terms of reduced machining costs and lead times compared to the traditional route involving machining of the annealed state followed by heat treatment, grinding\\/EDM and manual finishing. But machinability of hard material throu gh conventional machining is hindered due to excessive wear of the

M. A. Lajis; A. K. M. N. Amin; A. N. M. Karim; H. C. D. M. Radzi; T. L. Ginta

2009-01-01

212

ORIGINAL PAPER Growth and frost hardening of European aspen  

E-print Network

The native European aspen grew faster, whereas hybrid aspen Ã? aspen frost hardened faster and exhibited of native species, thus threatening their overall fitness (Vanden Broeck et al. 2005). European aspen). It has been demonstrated that hybrid aspen, a man-made cross between European aspen and North American

Paris-Sud XI, Université de

213

Work-hardening in the drilling of austenitic stainless steels  

Microsoft Academic Search

Due to specific properties arising from their structure (high toughness, work-hardening, low heat conductivity) austenitic stainless steels belong to the group of materials that are difficult to machine. Drilling of these steels is even more difficult as it is not easy to follow the cutting process going on at the drill tip. The paper presents an experimental investigation of the

S Dolinšek

2003-01-01

214

A Radiation Hardened Reconfigurable FPGA Shankarnarayanan Ramaswamy1  

E-print Network

Size Isolation Device Options S/D Engineering Supply Voltages Gate Electrodes Metal Levels Poly.ramaswamy@baesystems.com Abstract--A new high density, high performance radiation hardened, reconfigurable Field Programmable Gate & Diffusion Silicide 150nm Shallow Trench Isolation 26 Ã? / 70 Ã? Halo with S/D Extensions 1.5V / 3.3V N+ Poly

Manohar, Rajit

215

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

216

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

217

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

218

49. INTERIOR VIEW OF HARDENER AREA SHOWING GAUGE THAT MEASURES ...  

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

49. INTERIOR VIEW OF HARDENER AREA SHOWING GAUGE THAT MEASURES HARDNESS, THE NAIL MUST BREAK IN THE CENTER RANGE OF THE CURVED BAR TO HAVE THE CORRECT HARDNESS (THE NAIL WILL BREAK TOO EASILY IF TOO HARD AND WILL BEND TOO MUCH IF TOO SOFT) - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

219

THE PHYSICAL METALLURGY OF PRECIPITATION-HARDENABLE STAINLESS STEELS  

Microsoft Academic Search

The present knowledge on the physical metallurgy of precipitation-; hardenable stainless steels is presented. The alloys discussed include the ; martensitic types (Stainless W and 17-4 PH), the semiaustenitic types (177 PH, PH ; 15-7 Mo, AM 350, and AM 355), and the austenitic types (A-286 and HNM). The ; areas of metallurgy common to most or all of these

D. C. Ludwigson; A. M. Hall

1959-01-01

220

Machinability of hardened steel using alumina based ceramic cutting tools  

Microsoft Academic Search

Alumina based ceramic cutting tool is an attractive alternative for carbide tools in the machining of steel in its hardened condition. These ceramic cutting tools can machine with high cutting speed and produce good surface finish. The wear mechanism of these ceramic cutting tools should be properly understood for greater utilization. Two types of ceramic cutting tools namely Ti[C,N] mixed

A Senthil Kumar; A Raja Durai; T Sornakumar

2003-01-01

221

SEE-Hardened-by-Design Area-Efficient SRAMs  

Microsoft Academic Search

With the advent of error detection and correction (EDAC) schemes for SRAMs, the reliability of SRAMs in radiation environments has improved. However, there are several problems that still need to be addressed. In particular, single-event-transient (SET) hardening of peripheral circuitry, including row and column decoders, sense amplifiers, as well as the EDAC circuitry itself, has not been adequately addressed. We

Duncan Yu Lam; J. Lan; L. McMurchie; C. Sechen

2005-01-01

222

A new hardening law for strain gradient plasticity  

Microsoft Academic Search

A new hardening law of the strain gradient theory is proposed in this paper, which retains the essential structure of the incremental version of conventional J2 deformation theory and obeys thermodynamic restrictions. The key feature of the new proposal is that the term of strain gradient plasticity is represented as an internal variable to increase the tangent modulus. This feature

S. H. Chen; T. C. Wang

2000-01-01

223

Refinement of precipitate distributions in an age-hardenable Mg–Sn alloy through microalloying  

Microsoft Academic Search

It has been known for some time that trace additions (hardenable alloys can have a disproportionate effect on the hardening response. This is now known to be related to the formation of heterogeneities (clusters or precipitates) on the matrix lattice at which the nucleation of hardening precipitates may be enhanced leading to a

C. L. Mendis; C. J. Bettles; M. A. Gibson; S. Gorsse; C. R. Hutchinson

2006-01-01

224

Shear band formation in heavily cold rolled 70-30 brass  

NASA Astrophysics Data System (ADS)

Blocks of 70 ?m grain size 70-30 brass have been cold rolled up to a strain of 2.4. Polished parallelepiped samples have been prepared from the cold rolled strips and deformed in plane strain in a well-lubricated channel die. Three specimen orientations have been studied. Optical metallography has been used to determine the critical strain for the onset of shear banding and the angle which the shear bands make with the compression plane in the channel die. The strain at which shear bands form and the angle which they make with the compression plane depend upon the specimen orientation. The stress-strain curves show two distinct work hardening stages. Shear bands form under a positive rate of work hardening.

Nourbakhsh, Said; Song, Qing

1989-07-01

225

Microstructural and bulk property changes in hardened cement paste during the first drying process  

SciTech Connect

This paper reports the microstructural changes and resultant bulk physical property changes in hardened cement paste (hcp) during the first desorption process. The microstructural changes and solid-phase changes were evaluated by water vapor sorption, nitrogen sorption, ultrasonic velocity, and {sup 29}Si and {sup 27}Al nuclear magnetic resonance. Strength, Young's modulus, and drying shrinkage were also examined. The first drying process increased the volume of macropores and decreased the volume of mesopores and interlayer spaces. Furthermore, in the first drying process globule clusters were interconnected. During the first desorption, the strength increased for samples cured at 100% to 90% RH, decreased for 90% to 40% RH, and increased again for 40% to 11% RH. This behavior is explained by both microstructural changes in hcp and C–S–H globule densification. The drying shrinkage strains during rapid drying and slow drying were compared and the effects of the microstructural changes and evaporation were separated.

Maruyama, Ippei, E-mail: ippei@dali.nuac.nagoya-u.ac.jp [Graduate School of Environmental Studies, Nagoya University, ES Building, No. 546, Furo-cho, Chikusa-ku, Nagoya 464–8603 (Japan); Nishioka, Yukiko; Igarashi, Go [Graduate School of Environmental Studies, Nagoya University, ES Building, No. 539, Furo-cho, Chikusa-ku, Nagoya 464–8603 (Japan); Matsui, Kunio [Products and Marketing Development Dept. Asahi-KASEI Construction Materials Corporation, 106 Someya, Sakai-machi, Sashima-gun, Ibaraki, 306–0493 (Japan)

2014-04-01

226

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

227

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

228

Nanoscale characterization of the biomechanical hardening of bovine zona pellucida.  

PubMed

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

2012-11-01

229

Improved sperm cryopreservation using cold cryoprotectant.  

PubMed

It has generally been assumed that very rapid cooling above freezing point would be deleterious to human sperm because it would result in cold shock. Consequently, most routine cryopreservation protocols involve the use of warm (20-30 degrees C) cryoprotectant and slow cooling above the freezing point in order to minimise the risk of cold shock. In order to test this assumption, we added an equal volume of cold (4 degrees C) cryoprotectant in a single aliquot to warm (20, 30 or 37 degrees C) semen to induce rapid cooling. The results of this procedure were compared with those obtained using warm cryoprotectant or with the routine cryopreservation protocol used in this laboratory. The use of cold cryoprotectant resulted in a significant (P = 0.016) improvement (mean 63%, range 42%-79%) in post-thaw motility recovery compared with a standard procedure(mean 47%, range 35%-67%) and a significant (P = 0.016) improvement in post-thaw sperm velocity. A cold glycerol/egg yolk/citrate (GEYC) mixture also gave significantly higher motility recovery than GEYC equilibrated to either room temperature (20 degrees C) or body temperature (37 degrees C). Sperm frozen using the cold cryoprotectant protocol were as efficient at binding to and penetrating the human zona pellucida as sperm frozen with a standard protocol. The modified cryopreservation procedure may lead to improved pregnancy rates in donor insemination and in vitro fertilisation. Further investigation is required to determine how the cold cryoprotectant improves the cryopreservation outcome. PMID:14984694

Clarke, G N; Liu, D Y; Baker, H W G

2003-01-01

230

Cold fusion, Alchemist's dream  

SciTech Connect

In this report the following topics relating to cold fusion are discussed: muon catalysed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalysed cold fusion; vibrational mechanisms in excited states of D{sub 2} molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D{sub 2} fusion at low energies; fusion of deuterons into {sup 4}He; secondary D+T fusion within the hydrogenated metal lattice; {sup 3}He to {sup 4}He ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of {sup 3}He/{sup 4}He.

Clayton, E.D.

1989-09-01

231

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

232

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.

COMET

2001-06-18

233

Springback After the Lateral Bending of T-Section Rails of Work-Hardening Materials  

NASA Astrophysics Data System (ADS)

This paper studies the springback after the lateral bending of T-section rails, considering the work-hardening materials. A linear-hardening model and an elastic-plastic power-exponent hardening model of the material are adopted and compared with the real experimental stress-strain curve obtained from the uniaxial tension tests. The analytical formulas for the springback and residual curvatures are given. The numerical results indicate that the material hardening directly affects the accuracy of springback prediction compared with the experimental results. Besides, springback prediction is not sensitive to hardening parameters in the beginning of elastic-plastic bending deformation. Although there is an apparent yield stage in the true stress-strain curve, the adopted hardening models can achieve an allowable relative error, if hardening parameters are properly selected.

Song, Youshuo; Yu, Zhonghua

2013-11-01

234

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

235

Effect of high CO{sub 2} on cold acclimation and deacclimation of three conifers  

SciTech Connect

Atmospheric CO{sub 2} levels are rising, and whether or not this leads to a climate change, high CO{sub 2} is known to have some direct effects of plants. One aspect that has only begun to be explored is possible effects on cold hardiness. Well adapted woody plants can tolerate the lowest temperatures to which they may be exposed at all times of the year. Every year temperate and boral woody plants must cold harden in a timely manner in autumn, become hardy enough to withstand the coldest winter temperatures, and not lose their hardiness prematurely in the spring. The authors objective was to determine the effect of elevated CO{sub 2} on cold acclimation and deacclimation of three commercially important conifers. Seedlings of three conifers were cold hardened and dehardened in growth rooms under 350 or 700 ppm CO{sub 2}. High CO{sub 2} had little effect on cold hardiness of radiata pine, but increased autumn and spring hardiness of Douglas-fir. High CO{sub 2} increased hardiness of ponderosa pine in autumn and decreased it in the spring.

Tinus, R.W. [Forest Service, Flagstaff, AZ (United States). Rocky Mountain Forest and Range Experiment Station; Greer, D.H.; Robinson, L.A. [Hort + Research Inst., Palmerston North (New Zealand)

1995-12-31

236

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

237

A Brief Discussion of Radiation Hardening of CMOS Microelectronics  

SciTech Connect

Commercial microchips work well in their intended environments. However, generic microchips will not fimction correctly if exposed to sufficient amounts of ionizing radiation, the kind that satellites encounter in outer space. Modern CMOS circuits must overcome three specific concerns from ionizing radiation: total-dose, single-event, and dose-rate effects. Minority-carrier devices such as bipolar transistors, optical receivers, and solar cells must also deal with recombination-generation centers caused by displacement damage, which are not major concerns for majority-carrier CMOS devices. There are ways to make the chips themselves more resistant to radiation. This extra protection, called radiation hardening, has been called both a science and an art. Radiation hardening requires both changing the designs of the chips and altering the ways that the chips are manufactured.

Myers, D.R.

1998-12-18

238

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

239

Poromechanical behaviour of hardened cement paste under isotropic loading  

E-print Network

The poromechanical behaviour of hardened cement paste under isotropic loading is studied on the basis of an experimental testing program of drained, undrained and unjacketed compression tests. The macroscopic behaviour of the material is described in the framework of the mechanics of porous media. The poroelastic parameters of the material are determined and the effect of stress and pore pressure on them is evaluated. Appropriate effective stress laws which control the evolution of total volume, pore volume, solid volume, porosity and drained bulk modulus are discussed. A phenomenon of degradation of elastic properties is observed in the test results. The microscopic observations showed that this degradation is caused by the microcracking of the material under isotropic loading. The good compatibility and the consistency of the obtained poromechanical parameters demonstrate that the behaviour of the hardened cement paste can be indeed described within the framework of the theory of porous media.

Ghabezloo, Siavash; Guédon, Sylvine; Martineau, Francçois; Saint-Marc, Jérémie

2008-01-01

240

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

241

Age hardening of 6061/alumina-silica fiber composite  

SciTech Connect

Continuous alumina-silica fiber (Altex of Sumitomo) which yields high performance composites with some aluminium alloys was tried for squeeze cast 6061 based composites with volume fractions of 0.5 and 0.32, and the matrix microhardness and resistivity changes during age hardening were studied. The matrix in the composites hardened much more than the unreinforced alloy. Microhardness increases of up to 70 VPN above the solution treated condition at various aging temperatures were observed. The resistivity variation indicated an appreciable state of internal stress which continued to persist even when hardness fell by overaging. Energy dispersive X-ray analysis indicated that the regions close to the fibers had a higher silicon content than the matrix, and amorphous silica in the fiber may have a role in the formation of an enriched layer which may help the bonding and strength in the composite.

Khangaonkar, P.R.; Shamsul, J.B.; Azmi, R. [Univ. Sains Malaysia, Tronoh (Malaysia)

1994-12-31

242

Aging hardening of aluminum alloy-fly ash composites  

SciTech Connect

The aluminum alloy (A356.2)-fly ash composites were produced by stir mixing fly ash into aluminum melt. The fly ash added to the melts was 5% by weight. Selected mechanical properties in the as cast and after age hardening of the composites were examined. The microstructure was also examined using optical and transmission electron microscope (TEM). The A356.2-5 wt % fly ash composite castings showed a notable increase in hardness over the base alloy. The aging behavior the A356.2-5 wt % fly ash composite of as well as the monolithic alloy was followed by a measure of hardness and compressive strength as a function of aging time after quenching. The A356.2-5 wt % fly ash composite responds to age hardening in a manner similar to the matrix alloy.

Rohatgi, P.K.; Guo, R.Q. [Univ. of Wisconsin, Milwaukee, WI (United States). Dept. of Materials

1999-11-01

243

Surface hardening of two cast irons by friction stir processing  

Microsoft Academic Search

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

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

2009-01-01

244

Water vapour sorption experiments on hardened cementitious materials  

Microsoft Academic Search

This paper forms the first part of a series. In this first part, a broad range of normal and high-performance (HP) hardened cement pastes and concretes is studied under both laboratory and in-situ conditions.Water vapour desorption–adsorption experiments are carried out by means of the saturated salt solution method on very thin specimens. The effect of various parameters and in particular

Véronique Baroghel-Bouny

2007-01-01

245

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

246

Circuit demonstration of radiation hardened chalcogenide non-volatile memory  

Microsoft Academic Search

BAE SYSTEMS in Manassas, Virginia, and Ovonyx, Inc., have previously reported electrical test results fiom stand-alone single-bit chalcogenide memories. In this paper we present a description of two test chips, one that has been used to integrate the chalcogenide memory element with BAE SYSTEMS' radiation hardened 0.5 pm CMOS technology, and another to develop 64 kbit arrays with full write-read

J. Maimon; K. Hunt; J. Rodgers; L. Burcin; K. Knowles

2003-01-01

247

Radiation Hardened Phase Change Chalcogenide Memory: Progress and Plans  

Microsoft Academic Search

The chalcogenide material used for phase-change applications in rewritable optical storage (Ge2Sb2Te5) has been integrated with a 0.5µm radiation hardened CMOS process to produce 64kbit memory arrays. On selected arrays electrical testing demonstrated up to 100% memory cell yield, 100ns programming and read speeds, and write currents as low as 1mA\\/bit. Devices functioned normally from -55°C to 125°C. Write\\/read endurance

J. Maimon; J. Rodgers; L. Burcin; K. Knowles

248

Improvements on radiation-hardened performance of static induction transistor  

Microsoft Academic Search

The radiation-hardened performances of static induction transistor (SIT) have been studied in depth in this paper. The effects\\u000a of radiation of electron beam on the I–V characteristics, carrier distribution and potential distribution in the channel of\\u000a SIT have been represented. A large number of electron-hole pairs are generated in the depletion region of reversely biased\\u000a gate-channel PN junction. The radiation-generated

YongShun Wang; XianLiang Luo; HaiRong Li; ZiTing Wang; Rong Wu; CaiZhen Zhang; SiYuan Li

2010-01-01

249

Designing and Testing a Radiation Hardened 8051-like Microcontroller  

Microsoft Academic Search

This paper presents a prototype of a hardened version of the 8051 micro-controller, able to assure reliable operation in the presence of bit flips caused by radiation. Aiming at avoiding such faults in the 8051 micro-controller, Hamming code protection was used in its SRAM memory and registers. This paper shows implementation details of this technique in the micro-controller VHDL description

F. G. Lima; S. Rezgui; M. Lubaszewski; R. Velazco

2000-01-01

250

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

251

Dynamic response of two strain-hardened aluminum alloys  

Microsoft Academic Search

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

J. M. Boteler; D. P. Dandekar

2006-01-01

252

Radiation hardening of ASICs in deep submicron CMOS technologies  

NASA Astrophysics Data System (ADS)

The radiation hardness is a critical issue for a number of ASIC applications. The ASICs used in space, physics experiments or in medical instrumentations have to deal with the radiation and its effects. The paper gives a short overview of the radiation-induced effects in the CMOS devices and presents design and system aspects of the ASIC radiation hardening. Examples of chips designed for heavy radiation environment are presented.

Szczygiel, Robert

2005-02-01

253

Elastic constant versus temperature behavior of three hardened maraging steels  

NASA Technical Reports Server (NTRS)

Elastic constants of three maraging steels were determined by measuring ultrasonic velocities. Annealed steels show slightly lower bulk moduli and considerably lower shear moduli than hardened steels. All the elastic constants (Young's modulus, shear modulus, bulk modulus and Poisson's ratio) show regular temperature behavior between 76 and 400 K. Young's modulus and the shear modulus increase with increasing yield strength, but the bulk modulus and Poisson's ratio are relatively unchanged. Elastic anisotropy is quite small.

Ledbetter, H. M.; Austin, M. W.

1985-01-01

254

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.

255

An energy-based beam hardening model in tomography  

Microsoft Academic Search

As a consequence of the polychromatic x-ray source, used in micro-computer tomography (µCT )a nd in medical CT, the attenuation is no longer a linear function of absorber thickness. If this nonlinear beam hardening effect is not compensated, the reconstructed images will be corrupted by cupping artefacts. In this paper, a bimodal energy model for the detected energy spectrum is

E. Van de Casteele; D. Van Dyck; J. Sijbers; E. Raman

2002-01-01

256

Mechanism of the hardening effect of solvents on polymers  

Microsoft Academic Search

UDC 678.541.68 In previous reports [1-3], we described a method for hardening acrylic plastic products by brief treatment of their surface with heated solvents. The improvement in basic physicomechanica l characteristics resulted from the action of heat onthe molecular structure of the surface layers, solution, and closure of surface defects. Chemical analysis of the working solutions (solvents) showed that they

V. L. Avramenko; E. Yu. Novik; A. A. Shturman

1975-01-01

257

Modelling direction-dependent hardening in magnesium sheet forming simulations  

Microsoft Academic Search

In this work, a model capturing anisotropic hardening during plastic deformation under monotonic loading is proposed. For\\u000a this purpose, the anisotropic plastic potential coefficients are assumed to be functions of a measure of the accumulated plastic\\u000a strain. This model is applied to describe the plastic behavior of a magnesium alloy (ZM21) sheet at room temperature. The\\u000a selected plastic potential accounts

Dirk Steglich; Wolfgang Brocks; Jan Bohlen; Frederic Barlat

2011-01-01

258

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

259

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

260

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

261

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

262

An Evaluation of the Corrosion and Mechanical Performance of Interstitially Surface-Hardened Stainless Steel  

NASA Astrophysics Data System (ADS)

A surface hardening technique called "interstitial hardening" is commercially available, whereby interstitial carbon atoms are introduced into stainless steel surfaces without the formation of carbides. Surface hardening of machine elements such as impellors or fasteners would improve performance regarding cavitation and galling resistance, and has intensified interest in this process. However, there remains a need to characterize and validate the specific performance characteristics of the hardened materials. This paper describes experimental testing conducted on 316L stainless steel that has been surface hardened using available commercial techniques, using carbon as the interstitial atom. The corrosion performance of the hardened surface is assessed using electrochemical potentiodynamic testing to determine the breakdown potential in 3.5 wt.% NaCl solution to identify the most promising method. The hardness and thickness of the surface-hardened layer is characterized and compared using metallography and microhardness profiling. Corrosion fatigue and slow strain rate testing of untreated, hardened, and damaged, hardened surfaces exposed to ASTM seawater is conducted. Finally, critical galling stresses are determined and compared. Post-test examination of damage attempts to identify mechanisms of material failure and characterize how corrosion-assisted cracks initiate and grow in surface-hardened materials.

Jones, Jennifer L.; Koul, Michelle G.; Schubbe, Joel J.

2014-06-01

263

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

264

Cold hardiness in molluscs  

NASA Astrophysics Data System (ADS)

Molluscs inhabit all types of environments: seawater, intertidal zone, freshwater and land, and of course may have to deal with subzero temperatures. Ectotherm animals survive cold conditions by avoiding it by extensive supercooling (freezing avoidant species) or by bearing the freezing of their extracellular body fluids (freezing tolerant species). Although some studies on cold hardiness are available for intertidal molluscs, they are scarce for freshwater and terrestrial ones. Molluscs often exhibit intermediary levels of cold hardiness, with a moderate or low ability to supercool and a limited survival to the freezing of their tissues. Several factors could be involved: their dependence on water, their ability to enter dormancy, the probability of inoculative freezing in their environment, etc. Size is an important parameter in the development of cold hardiness abilities: it influences supercooling ability in land snails, which are rather freezing avoidant and survival to ice formation in intertidal organisms, which generally tolerate freezing.

Ansart, Armelle; Vernon, Philippe

2003-05-01

265

Colds and the Flu  

MedlinePLUS

... with green- or yellow-colored discharge) Sore throat Cough Sneezing Fatigue Muscle aches Headache Watery eyes Cold ... aches, especially in your back, arms and legs Cough Headache Loss of appetite What is H1N1 flu? ...

266

Beware the Bitter Cold  

MedlinePLUS

... not be available after 05/14/2015) By Robert Preidt Friday, February 13, 2015 Related MedlinePlus Pages ... risk for heat loss in cold temperatures," Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital ...

267

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

268

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

269

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

270

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

271

Teaching in a Cold Environment.  

ERIC Educational Resources Information Center

The key to a successful program in a cold environment lies in dealing with the cold while still accomplishing program goals and objectives. Teachers and students must be aware of physiological and psychological reactions to the cold, cold injuries and their treatment, and techniques for staying warm. (SB)

Ewert, Alan

1979-01-01

272

Endolithic microbial life in hot and cold deserts  

NASA Technical Reports Server (NTRS)

Endolithic microorganisms (those living inside rocks) occur in hot and cold deserts and exist under extreme environmental conditions. These conditions are discussed on a comparative basis. Quantitative estimates of biomass are comparable in hot and cold deserts. Despite the obvious differences between the hot and cold desert environment, survival strategies show some common features. These endolithic organisms are able to 'switch' rapidly their metabolic activities on and off in response to changes in the environment. Conditions in hot deserts impose a more severe environmental stress on the organisms than in the cold Antarctic desert. This is reflected in the composition of the microbial flora which in hot desert rocks consist entirely of prokaryotic microorganisms, while under cold desert conditions eukaryotes predominate.

Friedmann, E. I.

1980-01-01

273

Genetics Home Reference: Familial cold autoinflammatory syndrome  

MedlinePLUS

... the disorder. Where can I find information about diagnosis or management of familial cold autoinflammatory syndrome? These ... people use for familial cold autoinflammatory syndrome? cold hypersensitivity familial cold-induced autoinflammatory syndrome familial cold urticaria ...

274

Characteristic Sizes for Exhaustion-Hardening Mechanism of Compressed Cu Single-Crystal Micropillars  

Microsoft Academic Search

The stress-strain response of Cu single-crystal compression micropillar containing initial dislocation network is investigated by three-dimensional discrete dislocation dynamics simulations. The results demonstrate that the stress-strain curves can be divided into three distinct types with increasing the sizes of micropillars: the three-stage exhaustion hardening, the multi-stage mixed hardening and the two-stage conventional forest hardening. The characteristic sizes of the micropillars

Yuan Gao; Zhuo Zhuang; Zhan-Li Liu; Xue-Chuan Zhao; Zhao-Hui Zhang

2010-01-01

275

Development of a Pressure-Dependent Constitutive Model with Combined Multilinear Kinematic and Isotropic Hardening  

NASA Technical Reports Server (NTRS)

The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented. The constitutive model is developed using the ABAQUS user material subroutine (UMAT). First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. The method for implementing the new constitutive model into ABAQUS is given.

Allen Phillip A.; Wilson, Christopher D.

2003-01-01

276

Two Parameters Describing Cyclic Hardening\\/Softening Behaviors of Metallic Materials  

Microsoft Academic Search

In this article, cyclic hardening\\/softening behaviors of metallic materials are studied by using 40 alloys’ test results.\\u000a In the analysis, two parameters are introduced: one parameter is new fracture ductility parameter; the other is cyclic hardening\\/softening\\u000a factor. The new fracture ductility parameter expresses cyclic hardening\\/softening. According to the criterion, there are three\\u000a critical values—2, 20, and 65.4%. When the new

Zhongping Zhang; Jing Li; Qiang Sun; Yanjiang Qiao; Chunwang Li

2009-01-01

277

Effect of prior cold work on the martensite transformation in SAE 52100  

SciTech Connect

Numerous publications refer to the phase transformations and properties of SAE 52100 steel, and this paper concerns itself with the effect of prior cold deformation on the martensitic hardening response. The A /SUB c1/ and A /SUB c3/ temperatures are lowered due to cold work as is the M /SUB s/ with a resultant increase in the retained austenite content for a given hardening cycle. Significantly, the prior cold deformation results in a refinement of the austenite grain size. The low angle dislocation cells produced by the cold deformation recover during the heating to the austenitizing temperature to form fine ferrite subgrains. The intersections of the fine ferrite subgrains with the spheroidal carbides in the soft annealed microstructures are preferential sites for nucleation of austenite. This results in finer austenite grains, which produces accelerated carbide dissolution and austenite alloy enrichment compared to unworked, soft annealed structures. The mechanism for the accelerated austenitization is significant in predicting heat treatment response from published phase transformation data for SAE 52100 steel.

Beswick, J.

1984-02-01

278

Cold Acclimation and Freezing Tolerance (A Complex Interaction of Light and Temperature).  

PubMed Central

By comparing growth under five different temperature and irradiance regimes (20[deg]C and 800, 250, and 50[mu]mol m-2 s-1 and 5[deg]C and 250 and 50 [mu]mul m-2 s-1), we have examined the effects of light, temperature, and the relative reduction state of photosystem II on plant morphology, freezing tolerance (lethal temperature at which freezing injury occurs [LT50]), transcript levels of Lhcb and two cold-stimulated genes (Wcs19 and Wcs120), and photosynthetic adjustment in winter rye (Secale cereale L. cv Musketeer). We show, for the first time to our knowledge, that in addition to adjustments in photosynthetic capacity, nonphotochemical quenching capacity and tolerance to photoinhibition, the accumulation of the cold-induced transcript Wcs19, and the compact plant morphology usually associated with cold-hardening are correlated with the relative reduction state of photosystem II rather than with growth temperature or growth irradiance per se. In contrast, the acquisition of maximal LT50, as well as Lhcb and Wcs120 mRNA accumulation, appears to be dependent on both growth temperature and growth irradiance but in an independent, additive manner. The results are discussed with respect to the possible role of the modulation of chloroplastic redox poise in photosynthetic acclimation to cold-hardening temperatures and the attainment of maximal LT50. PMID:12223720

Gray, G. R.; Chauvin, L. P.; Sarhan, F.; Huner, NPA.

1997-01-01

279

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

280

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.

281

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

282

Influence of metal acetylacetonates on the rate of hardening of epoxy oligomers by amines  

SciTech Connect

Metal acetylacetonates, M(AA)/sub n/, have various effects on the reactivity of epoxy compositions, but are known mainly as accelerators of hardening of epoxy resins by dicyanodiamide, anhydrides of dicarboxylic acids, and phenols. The substances studied in this paper were ED-22 epoxy-Bisphenol A oligomer having an epoxy equivalent of 194, and acetylacetonates of CoS, NiS , and FeT . Diethylenetriamine (DETA), 4,4'-diaminodiphenylmethane (DAM), and UP-606/2 tris(dimethy-p-aminomethyl) phenol were used as hardeners. The hardening rates of the compositions were studied by measurement of the volume resistivity of the hardening systems and of the gel time.

Nazarova, Z.F.; Evtushenko, G.A.; Palagushkina, L.A.; Artemova, V.V.

1986-05-10

283

Undrained heating and anomalous pore-fluid pressurization of a hardened cement paste  

NASA Astrophysics Data System (ADS)

Temperature increase in a fluid-saturated porous material in undrained condition leads to volume change and pore pressure increase due to the discrepancy between the thermal expansion coefficients of the pore fluid and of the pore volume. This increase of the pore fluid pressure induces a reduction of the effective mean stress, and can lead to shear failure or hydraulic fracturing. This phenomenon is important is important in environmental engineering for radioactive (exothermal) waste disposal in deep clay geological formations as well as in geophysics in the studies of rapid fault slip events when shear heating tends to increase the pore pressure and to decrease the effective compressive stress and the shearing resistance of the fault material (Sulem et al. 2007). This is also important in petroleum engineering where the reservoir rock and the well cement lining undergo sudden temperature changes for example when extracting heavy oils by steam injection methods. This rapid increase of temperature could damage cement sheath integrity of wells and lead to loss of zonal isolation. The values of the thermal pressurization coefficient, defined as the pore pressure increase due to a unit temperature increase in undrained condition, is largely dependent upon the nature of the material, the state of stress, the range of temperature change, the induced damage. The large variability of the thermal pressurization coefficient reported in the literature for different porous materials with values from 0.01MPa/°C to 1.5MPa/°C highlights the necessity of laboratory studies. This phenomenon of thermal pressurization is studied experimentally for a fluid-saturated hardened cement paste in an undrained heating test. Careful analysis of the effect of the dead volume of the drainage system of the triaxial cell has been performed based on a simple correction method proposed by Ghabezloo and Sulem (2008, 2009). The drained and undrained thermal expansion coefficients of the hardened cement paste are also measured in the heating tests. The measured value of the thermal pressurization coefficient is found equal to 0.6MPa/°C and the test results unexpectedly show that it does not change with temperature between 20°C and 55°C. In most geomaterials, as shown experimentally by Ghabezloo and Sulem (2008), the temperature dependency of the thermal expansion of the pore fluid results in temperature dependency of the thermal pressurization coefficient. The observed anomalous thermal pressurization phenomenon is attributed to the anomalous thermal behaviour of cement paste pore fluid. The anomalous thermal behaviour of cement pore fluid is back analysed from the results of the undrained heating test and it is shown that the thermal expansion of the cement paste pore fluid is higher than the one of pure bulk water and is much less sensitive to temperature changes. This anomalous thermal behaviour is due to the confinement of the pore fluid in the very small pores of the microstructure of the cement paste, and also to the presence of dissolved ions in the pore fluid. References: 1.Sulem J., Lazar P., Vardoulakis I. (2007) Thermo-Poro-Mechanical Properties of Clayey Gouge and Application to Rapid Fault Shearing, Int. J. Num. Anal. Meth. Geomechanics, 31(3), 523-540 2.Ghabezloo S., Sulem J. (2008) Stress dependent thermal pressurization of a fluid-saturated rock. Rock Mechanics and Rock Engineering, in press, DOI 10.1007/s00603-008-0165-z. 3.Ghabezloo S., Sulem J., Saint-Marc, J. (2009) The effect of undrained heating on a fluid-saturated hardened cement paste. Cement and Concrete Research, 39(1), 54-64. 4.Ghabezloo S., Sulem J. (2009) Evaluation of the undrained thermo-poro-elastic parameters in a conventional triaxial cell: the effect of the dead volume of the drainage system. Submitted to Int J Rock Mech Min Sci.

Ghabezloo, S.; Sulem, J.; Saint-Marc, J.

2009-04-01

284

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

285

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

286

About quenching of rolls from deep-hardening steels  

Microsoft Academic Search

The possibilities of the use of deep-hardening steels for fabricating rolls up to 2200 mm in diameter are studied for steel\\u000a 35KhN3MFA as an example. The mechanical properties of the metal are studied for cooling rates ranging within 4000–50 K\\/h in\\u000a short-term tests at 20–550°C. The method of finite elements is used to compute the temperature field and the variation

I. A. Borisov; L. M. Levitan

2010-01-01

287

Ductility and work hardening in nano-sized metallic glasses  

NASA Astrophysics Data System (ADS)

In-situ nano-tensile experiments on 70 nm-diameter free-standing electroplated NiP metallic glass nanostructures reveal tensile true strains of ˜18%, an amount comparable to compositionally identical 100 nm-diameter focused ion beam samples and ˜3 times greater than 100 nm-diameter electroplated samples. Simultaneous in-situ observations and stress-strain data during post-elastic deformation reveal necking and work hardening, features uncharacteristic for metallic glasses. The evolution of free volume within molecular dynamics-simulated samples suggests a free surface-mediated relaxation mechanism in nano-sized metallic glasses.

Chen, D. Z.; Gu, X. W.; An, Q.; Goddard, W. A.; Greer, J. R.

2015-02-01

288

A radiation hardened 256 x 4 bulk CMOS RAM  

NASA Technical Reports Server (NTRS)

A radiation hardened version of the C2L process has been developed that utilizes all-low-temperature processes subsequent to channel oxidation. This process has been used on 1K RAMS. The RAMs functioned reliably at a dose of 200,000 rads (Si) and failed at a dose of 500,000 rads (Si). The 1K RAM is capable of operating from 7.5 to 12 volts and has an access time from address change of 160 nsec at 10 volts

Napoli, L. S.; Smeltzer, R. K.; Donnelly, R.; Yeh, J.

1982-01-01

289

Rapid Response  

NSDL National Science Digital Library

Rapid Response, a "knowledge resource specializing in policy advice for developing countries," is a new service from the World Bank. Mainly a fee-based service, the Rapid Response service also contains several valuable free resources. The service concentrates on several areas of expertise including investment climates; private participation in a variety of complex sectors such as telecommunications, water, and energy; and output-based aid. By far, the most useful tool offered on this site is Knowledge Resources, the database of papers, reports, case studies and related Websites. The database is searchable by keyword or by topic or resource type.

290

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

Microsoft Academic Search

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 in- duction of the CBF regulon (CBF-targeted genes), which contributes to an increase in

Sarah Fowler; Michael F. Thomashow

2002-01-01

291

Cold sea survival.  

NASA Technical Reports Server (NTRS)

Two prototype three-man life rafts were evaluated during the winter months in Arctic waters off Kodiak Island, Alaska, to assess potential survival problems and determine tolerance limits. Each raft incorporated thermal characteristics specifically designed for cold water. Water and air temperatures varied from 0 to +2 C and -5 to +4 C respectively. All subjects were removed upon reaching subjective tolerance. The results showed that none of the clothing assemblies was adequate to maintain a person in comfort even with dry boarding. No significant biochemical shifts in the blood or urine were found. The TUL raft was found to be superior in its thermal characteristics and afforded better subject protection. General tolerance for cold water immersion, wet and dry, and cold water raft exposures are depicted graphically, based on previously reported data.

Veghte, J. H.

1972-01-01

292

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

293

A radiation-hardened, computer for satellite applications  

SciTech Connect

This paper describes high reliability radiation hardened computers built by Sandia for application aboard DOE satellite programs requiring 32 bit processing. The computers highlight a radiation hardened (10 kGy(Si)) R3000 executing up to 10 million reduced instruction set instructions (RISC) per second (MIPS), a dual purpose module control bus used for real-time default and power management which allows for extended mission operation on as little as 1.2 watts, and a local area network capable of 480 Mbits/s. The central processing unit (CPU) is the NASA Goddard R3000 nicknamed the ``Mongoose or Mongoose 1``. The Sandia Satellite Computer (SSC) uses Rational`s Ada compiler, debugger, operating system kernel, and enhanced floating point emulation library targeted at the Mongoose. The SSC gives Sandia the capability of processing complex types of spacecraft attitude determination and control algorithms and of modifying programmed control laws via ground command. And in general, SSC offers end users the ability to process data onboard the spacecraft that would normally have been sent to the ground which allows reconsideration of traditional space-grounded partitioning options.

Gaona, J.I. Jr.

1996-08-01

294

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

295

Some aspects on plastic deformation of copper and copper–titanium carbide powder metallurgy composite preforms during cold upsetting  

Microsoft Academic Search

The densification, workability and strain hardening behaviour of sintered copper and Cu–7.5%TiC powder metallurgy (P\\/M) composite\\u000a preforms during cold upsetting were investigated by the constitutive model using the experimental data. Cold upsetting of\\u000a copper and Cu–7.5% TiC composite preforms having different aspect ratios were carried out and the formability behaviour of\\u000a the preforms under triaxial stress state was determined. The

R. Narayanasamy; V. Anandakrishnan; K. S. Pandey

2008-01-01

296

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

297

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

298

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 Patterning of gold-black infrared absorbing films by stencil lithography and hardening by polymer infusion and fragile, so that it is easily damaged by contact, shock, or air currents. The deposition process tends

Peale, Robert E.

299

Exploiting strain-hardening of tissue to increase contrast in elasticity imaging  

Microsoft Academic Search

Most biological tissues show strain hardening. For example, direct mechanical measurements on human prostate show up to a threefold increase in Young's modulus over a 10% deformation. In addition, strain-hardening behavior differs significantly between tissue types. In conventional elasticity imaging these effects produce strain dependent elastic contrast. Furthermore, image quality is suboptimal because softer tissues are imaged at higher strains

R. Q. Erkamp; S. Y. Emelianov; A. R. Skovoroda; X. Chen; M. O'Donnell

2000-01-01

300

Finite element simulation of springback for a channel draw process with drawbead using different hardening models  

Microsoft Academic Search

The objective of this work is to predict the springback of Numisheet’05 Benchmark#3 with different material models using the commercial finite element code ABAQUS. This Benchmark consisted of drawing straight channel sections using different sheet materials and four different drawbead penetrations. Numerical simulations were performed using Hill's 1948 anisotropic yield function and two types of hardening models: isotropic hardening (IH)

Aboozar Taherizadeh; Abbas Ghaei; Daniel E. Green; William J. Altenhof

2009-01-01

301

A model for reactive porous transport during re-wetting of hardened concrete  

E-print Network

A model for reactive porous transport during re-wetting of hardened concrete Michael Chapwanya model is developed that captures the transport of liquid water in hardened concrete, as well residing in the porous concrete matrix. The main hypothesis in this model is that the reaction product

Stockie, John

302

Improved manufacturing techniques for rf and laser hardening of missile domes, phase 1  

Microsoft Academic Search

The adaptation of an existing Pacific Northwest Laboratory (PNL) optical coating capability developed for high power fusion laser applications to the case of RF and laser hardening of plastic missile domes used by US Army (MICOM) is reported. RF hardening of Hellfire and Copperhead 1.06 micron missile domes by use of transparent conductive Indium Tin Oxide (ITO) coatings is demonstrated.

W. T. Pawlewicz; I. B. Mann; P. M. Martin; D. D. Hays; A. G. Graybeal

1982-01-01

303

Complex bulk-surface hardening of materials using a highly concentrated heat source  

Microsoft Academic Search

1.The complex bulk-surface hardening of the steels investigated using a highly concentrated heat source is an effective means of regulating their structure and crack resistance.2.The heat resistance of steels hardened by a highly concentrated heat source can be increased by the use of preliminary bulk quenching (as a result of the formation of a natural soft interlayer — tempered zone)

L. K. Leshchinskii; S. S. Samotugin; I. I. Pirch; A. V. Puiko; N. Kh. Solyanik

1988-01-01

304

Effect of strain hardening of the surface on the mechanical properties of samples at low temperatures  

Microsoft Academic Search

1.Machining of samples for mechanical tests leads to strain hardening in surface layers and residual stresses. With cooling to negative temperatures and deformation, such samples of austenitic steels form an elevated amount of martensite in the strain hardened zone, which leads to reduction of the plastic characteristics.2.The reduction of the plasticity depends on the depth of cutting in the last

D. V. Lebedev; B. M. Ovsyannikov

1971-01-01

305

Cold Sores (HSV-1)  

MedlinePLUS

... a person's lip) via the nerve endings. The area below the skin's surface, where the cold sore is going to appear, starts to tingle, itch, or burn. A red bump appears in the area about a day or so after the tingling. ...

306

Catching a Cold  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about infectious disease. The probe is designed to find out whether students use the germ theory to explain what causes an infectious disease like the common cold. This free selection includes the Preface, Introduction, Table of Contents, and the Index.

Joyce Tugel

2009-03-01

307

Tumor Cold Ischemia  

Cancer.gov

In a recently published manuscript in the journal of Molecular and Cellular Proteomics, researchers from the National Cancer Institutes (NCI) Clinical Proteomic Tumor Analysis Consortium (CPTAC) investigated the effect of cold ischemia on the proteome of fresh frozen tumors.

308

Galactic cold cores  

NASA Astrophysics Data System (ADS)

The project Galactic Cold Cores is studying the early stages of Galactic star formation using far-infrared and sub-millimetre observations of dust emission. The Planck satellite has located many sources of cold dust emission that are likely to be pre-stellar clumps in interstellar clouds. We have mapped a sample of Planck-detected clumps with the Herschel satellite at wavelengths 100-500 ?m. Herschel has confirmed the Planck detections of cold dust and have revealed a significant amount of sub-structure in the clumps. The cloud cores have colour temperatures in the range of 10-15 K. However, star formation is often already in progress with cold clumps coinciding with mid-infrared point sources. In less than half of the cases, the cloud morphology is clearly dominated by filamentary structures. The sources include both nearby isolated globules and more distant, massive clouds that may be off-the-plane counterparts of infrared dark clouds. The Herschel observations have been completed and the processed maps will be released to the community in 2013.

Juvela, M.

2015-03-01

309

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

310

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

311

Rapid Gel Formation and Adhesion in Photocurable and Biodegradable Block Copolymers with High DOPA Content  

E-print Network

polymerization is desired in certain clinically used materials such as surgical sealants and adhesives, where solRapid Gel Formation and Adhesion in Photocurable and Biodegradable Block Copolymers with High DOPA the use of adhesive plaques formed from hardened mussel adhesive proteins (MAPs). It is believed that 3

312

New distortional hardening model capable of predicting eight ears for textured aluminum sheet  

SciTech Connect

The effects of the anisotropy evolution and of the directionality in hardening on the predictions of the earing profile of a strongly textured aluminum alloy are investigated using a new distortional hardening model that incorporates multiple hardening curves corresponding to uniaxial tension along several orientations with respect to the rolling direction, and to biaxial tension. Yielding is described using a form of CPB06ex2 yield function (Plunkett et al. (2008)) which is tailored for metals with no tension-compression asymmetry. It is shown that even if directional hardening and its evolution are neglected, this yield function predicts a cup with eight ears as was observed experimentally. However, directional hardening can be of considerable importance for improved accuracy in prediction of the non-uniformity of the cup height profile.

Yoon, J. H.; Cazacu, O. [Department of Mechanical and Aerospace Engineering, University of Florida, REEF, Shalimar, FL 32579 (United States); Yoon, J. W. [Engineering and Industrial Science, Swinburne University of Technology, VIC 3122 (Australia); Dick, R. E. [Alcoa Technical Center, 100 Technical Dr., Alcoa Center, PA 15069-0001 (United States)

2011-05-04

313

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

314

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

315

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

316

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

317

Genomewide Transcriptional Analysis of the Cold Shock Response in Bacillus subtilis  

Microsoft Academic Search

Previous studies with two-dimensional gel electrophoresis techniques revealed that the cold shock response in Bacillus subtilis is characterized by rapid induction and accumulation of two classes of specific proteins, which have been termed cold-induced proteins (CIPs) and cold acclimatization proteins (CAPs), respectively. Only recently, the B. subtilis two-component system encoded by the desKR operon has been demonstrated to be essential

Carsten L. Beckering; Leif Steil; Michael H. W. Weber; Uwe Volker; Mohamed A. Marahiel

2002-01-01

318

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

319

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

320

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

321

[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

322

Dynamic iterative beam hardening correction (DIBHC) for an optimized assessment of cardiac perfusion in ECG-correlated CT  

Microsoft Academic Search

In cardiac perfusion examinations large concentrations of iodine in the ventricle cause beam hardening artifacts that lead to incorrect perfusion parameters. Beam hardening corrections are either implemented as simple precorrections which cannot account for higher order beam hardening effects, or as iterative approaches that are based on segmenting the original image into material distribution images. Conventional segmentation algorithms fail to

Philip Stenner; Bernhard Schmidt; Rainer Raupach; Thomas Allmendinger; Thomas Flohr; M. Kachelriess

2009-01-01

323

78 FR 57418 - Compliance With Order EA-13-109, Order Modifying Licenses With Regard to Reliable Hardened...  

Federal Register 2010, 2011, 2012, 2013, 2014

...with Regard to Reliable Hardened Containment Vents Capable...reliable operation of hardened containment vents during...the Mark I and Mark II designs. On March 12, 2012...requirements for a reliable hardened containment venting...temperatures, pressures, radiation levels, and...

2013-09-18

324

A search for the Mpemba effect: When hot water freezes faster then cold water  

Microsoft Academic Search

An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water,

James D. Brownridge

2010-01-01

325

Hot and Cold  

NSDL National Science Digital Library

In this chemistry challenge, learners discover that many chemical reactions involve heat loss or gain. With this understanding, they try to find a combination of chemicals that could be used to make an instant cold pack. They are given baking soda, ammonium nitrate, calcium chloride, and potassium chloride, along with vinegar and water (3% hydrogen peroxide and yeast can also be used). Learners combine chemicals into calorimeters, then use thermometers to measure how the temperature changes. Calorimeters can be made by pushing a heated test tube into home insulation foam (instructions in PDF) or can be purchased (one source is Flinn Scientific). The water and ammonium nitrate, and vinegar and baking soda, are candidates for making a cold pack.

Sciencenter

2014-08-27

326

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

327

Radial cold trap  

DOEpatents

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

Grundy, Brian R. (Greensburg, PA)

1981-01-01

328

Radial cold trap  

DOEpatents

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

Grundy, B.R.

1981-09-29

329

Cold Metastable NH molecules  

NASA Astrophysics Data System (ADS)

We report progress towards producing samples of cold trapped NH molecules using a stark decelerator. The NH molecule has a metastable state (a1Delta) approximately 1.5 eV above the ground state and a lifetime of several seconds. We create of a beam of cold NH molecules almost entirely in the a1 delta state by supersonic expansion and in situ photolysis of HNCO. We determine the rotational and translation temperatures of the beam using 2+1 resonance enhanced multi-photon ionization spectroscopy. The NH molecules are then slowed in a stark decelerator and trapped using static electric fields. Once the molecules are trapped, we will overlap a magnetic trap of ultracold rubidium atoms to study near-resonant quenching of metastable NH.

Fabrikant, Maya; Briles, Travis; Fitch, Noah; Lewandowski, Heather

2011-06-01

330

Cold nuclear fusion  

Microsoft Academic Search

The possibility that negative muons could catalyze nuclear fusion was suggested on theoretical grounds by F.C. Frank and A.D. Sakharov in the late 1940s; the first experimental observations of the process followed serendipitously a decade later, in experiments at Berkeley by L.W. Alvarez. The fastest mechanism for muon-catalyzed, or 'cold' fusion, was suggested by Vesman (1967); it depends on a

Johann Rafelski; Steven E. Jones

1987-01-01

331

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

332

Tradeoffs in Flight Design Upset Mitigation in State of the Art FPGAs: Hardened by Design vs. Design Level Hardening  

NASA Technical Reports Server (NTRS)

This presentation compares and contrasts the effectiveness and the system/designer impacts of the two main approaches to upset hardening: the Actel approach (RTSX-S and RTAX-S) of low-level (inside each flip-flop) triplication and the Xilinx approach (Virtex and Virtex2) of design-level triplication of both functional blocks and voters. The effectiveness of these approaches is compared using measurements made in conjunction with each of the FPGAs' manufacturer: for Actel, published data [1] and for Xilinx, recent results from the Xilinx SEE Test Consortium (note that the author is an active and founding member). The impacts involve Actel advantages in the areas of transistor-utilization efficiency and minimizing designer involvement in the triplication while the Xilinx advantages relate to the ability to custom tailor upset hardness and the flexibility of re-configurability. Additionally, there are currently clear Xilinx advantages in available features such as the number of I/O's, logic cells, and RAM blocks as well as speed. However, the advantage of the Actel anti-fuses for configuration over the Xilinx SRAM cells is that the latter need additional functionality and external circuitry (PROMs and, at least a watchdog timer) for configuration and configuration scrubbing. Further, although effectively mitigated if done correctly, the proton upset-ability of the Xilinx FPGAs is a concern in severe proton-rich environments. Ultimately, both manufacturers' upset hardening is limited by SEFI (single-event functional interrupt) rates where it appears the Actel results are better although the Xilinx Virtex2-family result of about one SEFI in 65 device-years in solar-min GCR (the more intense part of the galactic cosmic-ray background) should be acceptable to most missions

Swift, Gary M.; Roosta, Ramin

2004-01-01

333

Akt Activation Protects Liver Cells from Apoptosis in Rats during Acute Cold Exposure  

PubMed Central

Accidental deaths due to exposure to extremely low natural temperature happen every winter. Exposure to extreme cold causes injury of multiple organs. However, early responses of the bodies to acute extreme cold exposure remain incompletely understood. In this study, we found that hepatic glycogen was rapidly reduced in rats exposed to -15°C, and the key enzymes required for glycogenesis were upregulated in the livers of the cold-exposed rats. In line with the rapid consumption of glycogen, acute cold exposure induced a transient elevation of cellular ATP level, which lasted about one hour. The ATP level went back to basal level after two hours of cold exposure. Four hours of cold exposure resulted in cellular ATP depletion and cell apoptosis. The dynamic change of cellular ATP levels was well associated with Akt activation in cold-exposed liver cells. The activation of Akt was required for cold exposure-induced ATP elevation. Blockade of Akt activation diminished the transient increase of intracellular ATP content and exacerbated cell apoptosis during acute cold exposure. These results suggest that Akt activation plays a pivotal role in maintaining cellular bioenergy balance and promoting liver cell survival during acute cold exposure. PMID:23781144

Wang, Jiye; Chen, Yaoming; Zhang, Wenbin; Zheng, Gang; Meng, Shanshan; Che, Honglei; Ke, Tao; Yang, Jingrun; Chen, Jingyuan; Luo, Wenjing

2013-01-01

334

Experimental insight into the cyclic softening/hardening behavior of austenitic stainless steel using ultrasonic higher harmonics  

NASA Astrophysics Data System (ADS)

The correlation of cyclic hardening/softening behavior of 304 stainless steel (SS) was investigated using nonlinear ultrasonic wave technique. Results reveal that primary hardening leads to the increase of acoustic nonlinearity, while secondary hardening causes the reverse tendency. This distinct phenomenon is governed by two competitive mechanisms: in the primary-hardening stage, the ascended acoustic nonlinearity is related to the increase of planar dislocation structures. While in the second-hardening stage, the decrease of acoustic nonlinearity is partly caused by the development of cell structures. In addition, the deformation-induced martensitic transformation also contributes to the increase of acoustic nonlinearity under higher stress amplitudes.

Zhang, Jianfeng; Xuan, Fu-zhen; Xiang, Yanxun; Zhao, Peng

2014-11-01

335

Mathematical simulation of the plastic deformation of crystalline materials with a nanodispersed hardening phase  

NASA Astrophysics Data System (ADS)

The effect of the scale characteristics of a nanodispersed hardening phase on the strain hardening and evolution of the defect subsystem in materials with an fcc matrix has been studied with the use of a mathematical model including differential balance equations for the components of the strain defective subsystem. The two-stage character of evolution of the strain defect subsystem and the possibility of plastic shearing in dispersion-hardened materials due to either the motion of individual dislocations or the generation of numerous dislocations in the shear band were taken into consideration.

Kovalevskaya, T. A.; Daneiko, O. I.; Kolupaeva, S. N.

2007-11-01

336

Evolution of radiation defect and radiation hardening in heat treated SA508 Gr3 steel  

NASA Astrophysics Data System (ADS)

The formation of radiation defects and corresponding radiation hardening in heat-treated SA508 Gr3 steel after Fe ion irradiation were investigated by means of transmission electron microscopy and a nano-indentation technique. As the residual dislocation density is increased in the matrix, the formation of radiation defects is considerably weakened. Comparison between the characteristics of the radiation defect and an evaluation of radiation hardening indicates that a large dislocation loop contributes little to the radiation hardening in the heat-treated SA508 Gr3 steel.

Jin, Hyung-Ha; Kwon, Junhyun; Shin, Chansun

2014-01-01

337

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

338

Non Radiation Hardened Microprocessors in Spaced Based Remote Sensing Systems  

NASA Technical Reports Server (NTRS)

The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is a comprehensive suite of active and passive sensors including a 20Hz 230mj Nd:YAG lidar, a visible wavelength Earth-looking camera and an imaging infrared radiometer. CALIPSO flies in formation with the Earth Observing System Post-Meridian (EOS PM) train, provides continuous, near-simultaneous measurements and is a planned 3 year mission. CALIPSO was launched into a 98 degree sun synchronous Earth orbit in April of 2006 to study clouds and aerosols and acquires over 5 gigabytes of data every 24 hours. The ground track of one CALIPSO orbit as well as high and low intensity South Atlantic Anomaly outlines is shown. CALIPSO passes through the SAA several times each day. Spaced based remote sensing systems that include multiple instruments and/or instruments such as lidar generate large volumes of data and require robust real-time hardware and software mechanisms and high throughput processors. Due to onboard storage restrictions and telemetry downlink limitations these systems must pre-process and reduce the data before sending it to the ground. This onboard processing and realtime requirement load may mean that newer more powerful processors are needed even though acceptable radiation-hardened versions have not yet been released. CALIPSO's single board computer payload controller processor is actually a set of four (4) voting non-radiation hardened COTS Power PC 603r's built on a single width VME card by General Dynamics Advanced Information Systems (GDAIS). Significant radiation concerns for CALIPSO and other Low Earth Orbit (LEO) satellites include the South Atlantic Anomaly (SAA), the north and south poles and strong solar events. Over much of South America and extending into the South Atlantic Ocean the Van Allen radiation belts dip to just 200-800km and spacecraft entering this area are subjected to high energy protons and experience higher than normal Single Event Upset (SEU) and Single Event Latch-up (SEL) rates. Although less significant, spacecraft flying in the area around the poles experience similar upsets. Finally, powerful solar proton events in the range of 10MeV/10pfu to 100MeV/1pfu as are forecasted and tracked by NOAA's Space Environment Center in Colorado can result in Single Event Upset (SEU), Single Event Latch-up (SEL) and permanent failures such as Single Event Gate Rupture (SEGR) in some technologies. (Galactic Cosmic Rays (GCRs) are another source, especially for gate rupture) CALIPSO mitigates common radiation concerns in its data handling through the use of redundant processors, radiation-hardened Application Specific Integrated Circuits (ASIC), hardware-based Error Detection and Correction (EDAC), processor and memory scrubbing, redundant boot code and mirrored files. After presenting a system overview this paper will expand on each of these strategies. Where applicable, related on-orbit data collected since the CALIPSO initial boot on May 4, 2006 will be noted.

Decoursey, Robert J.; Estes, Robert F.; Melton, Ryan

2006-01-01

339

NINJA: a noninvasive framework for internal computer security hardening  

NASA Astrophysics Data System (ADS)

Vulnerabilities are a growing problem in both the commercial and government sector. The latest vulnerability information compiled by CERT/CC, for the year ending Dec. 31, 2002 reported 4129 vulnerabilities representing a 100% increase over the 2001 [1] (the 2003 report has not been published at the time of this writing). It doesn"t take long to realize that the growth rate of vulnerabilities greatly exceeds the rate at which the vulnerabilities can be fixed. It also doesn"t take long to realize that our nation"s networks are growing less secure at an accelerating rate. As organizations become aware of vulnerabilities they may initiate efforts to resolve them, but quickly realize that the size of the remediation project is greater than their current resources can handle. In addition, many IT tools that suggest solutions to the problems in reality only address "some" of the vulnerabilities leaving the organization unsecured and back to square one in searching for solutions. This paper proposes an auditing framework called NINJA (acronym for Network Investigation Notification Joint Architecture) for noninvasive daily scanning/auditing based on common security vulnerabilities that repeatedly occur in a network environment. This framework is used for performing regular audits in order to harden an organizations security infrastructure. The framework is based on the results obtained by the Network Security Assessment Team (NSAT) which emulates adversarial computer network operations for US Air Force organizations. Auditing is the most time consuming factor involved in securing an organization's network infrastructure. The framework discussed in this paper uses existing scripting technologies to maintain a security hardened system at a defined level of performance as specified by the computer security audit team. Mobile agents which were under development at the time of this writing are used at a minimum to improve the noninvasiveness of our scans. In general, noninvasive scans with an adequate framework performed on a daily basis reduce the amount of security work load as well as the timeliness in performing remediation, as verified by the NINJA framework. A vulnerability assessment/auditing architecture based on mobile agent technology is proposed and examined at the end of the article as an enhancement to the current NINJA architecture.

Allen, Thomas G.; Thomson, Steve

2004-07-01

340

Photosynthesis-dependent physiological and genetic crosstalk between cold acclimation and cold-induced resistance to fungal pathogens in triticale (Triticosecale Wittm.).  

PubMed

The breeding for resistance against fungal pathogens in winter triticale (Triticosecale Wittm.) continues to be hindered by a complexity of the resistance mechanisms, strong interaction with environmental conditions, and dependence on the plant genotype. We showed, that temperature below 4°C induced the plant genotype-dependent resistance against the fungal pathogen Microdochium nivale. The mechanism involved, at least, the adjustment of the reactions in the PSII proximity and photoprotection, followed by an improvement of the growth and development. The genotypes capable to develop the cold-induced resistance, showed a higher maximum quantum yield of PSII and a more efficient integration of the primary photochemistry of light reactions with the dark reactions. Moreover, induction of the photoprotective mechanism, involving at least the peroxidases scavenging hydrogen peroxide, was observed for such genotypes. Adjustment of the photosynthesis and stress acclimation has enabled fast plant growth and avoidance of the developmental stages sensitive to fungal infection. The same mechanisms allowed the quick regrow of plants during the post-disease period. In contrast, genotypes that were unable to develop resistance despite cold hardening had less flexible balancing of the photoprotection and photoinhibition processes. Traits related to: photosynthesis-dependent cold-acclimation and cold-induced resistance; biomass accumulation and growth; as well as protection system involving peroxidases; were integrated also at a genetic level. Analysing 95 lines of the mapping population SaKa3006×Modus we determined region on chromosomes 5B and 7R shared within all tested traits. Moreover, similar expression pattern of a set of the genes related to PSII was determined with the metaanalysis of the multiple microarray experiments. Comparable results for peroxidases, involving APXs and GPXs and followed by PRXs, indicated a similar function during cold acclimation and defense responses. These data provide a new insight into the cross talk between cold acclimation and cold-induced resistance in triticale, indicating a key role of photosynthesis-related processes. PMID:25666539

Szechy?ska-Hebda, Magdalena; W?sek, Iwona; Go??biowska-Pikania, Gabriela; Dubas, Ewa; ?ur, Iwona; W?dzony, Maria

2015-04-01

341

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.

Oregon Museum of Science and Industry

1997-01-01

342

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.

343

Radiation Hardened, Modulator ASIC for High Data Rate Communications  

NASA Technical Reports Server (NTRS)

Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values. High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency, but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with high power-efficiency (negligible HPA backoff).

McCallister, Ron; Putnam, Robert; Andro, Monty; Fujikawa, Gene

2000-01-01

344

Spectroscopic investigation of Ni speciation in hardened cement paste.  

PubMed

Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill, and liner materials) of repositories for radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level. X-ray absorption spectroscopy (XAS) coupled with diffuse reflectance spectroscopy (DRS) techniques were used to determine the local environment of Ni in cement systems. The Ni-doped samples were prepared at two different water/cement ratios (0.4, 1.3) and different hydration times (1 hour to 1 year) using a sulfate-resisting Portland cement. The metal loadings and the metal salts added to the system were varied (50 up to 5000 mg/kg; NO3(-), SO4(2-), Cl-). The XAS study showed that for all investigated systems Ni(ll) is predominantly immobilized in a layered double hydroxide (LDH) phase, which was corroborated by DRS measurements. Only a minor extent of Ni(ll) precipitates as Ni-hydroxides (alpha-Ni(OH)2 and beta-Ni(OH)2). This finding suggests that Ni-Al LDH, rather than Ni-hydroxides, is the solubility-limiting phase in the Ni-doped cement system. PMID:16646464

Vespa, M; Dähn, R; Grolimund, D; Wieland, E; Scheidegger, A M

2006-04-01

345

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

346

Switchable hardening of a ferromagnet at fixed temperature  

PubMed Central

The intended use of a magnetic material, from information storage to power conversion, depends crucially on its domain structure, traditionally crafted during materials synthesis. By contrast, we show that an external magnetic field, applied transverse to the preferred magnetization of a model disordered uniaxial ferromagnet, is an isothermal regulator of domain pinning. At elevated temperatures, near the transition into the paramagnet, modest transverse fields increase the pinning, stabilize the domain structure, and harden the magnet, until a point where the field induces quantum tunneling of the domain walls and softens the magnet. At low temperatures, tunneling completely dominates the domain dynamics and provides an interpretation of the quantum phase transition in highly disordered magnets as a localization/delocalization transition for domain walls. While the energy scales of the rare earth ferromagnet studied here restrict the effects to cryogenic temperatures, the principles discovered are general and should be applicable to existing classes of highly anisotropic ferromagnets with ordering at room temperature or above. PMID:20133728

Silevitch, D. M.; Aeppli, G.; Rosenbaum, T. F.

2010-01-01

347

Superconducting (radiation hardened) magnets for mirror fusion devices  

SciTech Connect

Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10/sup 10/ to 10/sup 11/ rads, while magnet stability must be retained after the copper has been exposed to fluence above 10/sup 19/ neutrons/cm/sup 2/.

Henning, C.D.; Dalder, E.N.C.; Miller, J.R.; Perkins, J.R.

1983-12-07

348

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

349

Cold War in Southern Africa  

Microsoft Academic Search

Review Article: Cold War in Southern Africa

  • Gary Baines, Peter Vale (eds.) (2008), Beyond the Border War: New Perspectives on Southern Africa’s Late-Cold War Conflicts, Pretoria: Unisa Press, ISBN 978 1 86888 456 8, xix + 342 pp. <\\/li>
  • Sue Onslow (ed.) (2009), Cold War in Southern Africa: White Power, Black Liberation, Abingdon: Routledge, ISBN 978 0 415 47420 7, 253

    Matthew Graham

    2010-01-01

350

Effects of Spark-Plasma Sintering Treatment on Cold-Sprayed Copper Coatings  

NASA Astrophysics Data System (ADS)

Cold-spray is well known as an effective coating technique to make thick metallic coatings. However, cold-sprayed metallic coatings usually have low tensile strengths due to low adhesion strength between particles, and low ductility due to low adhesion strength between particles and work hardening. Spark-plasma sintering (SPS) is a pressure-sintering technique that employs a large pulsed direct current. Compared to annealing heat treatment (AHT), SPS is expected to effectively improve the adhesion strength between particles in cold-sprayed metallic coatings. In order to investigate the effects of SPS, cold-sprayed Cu coatings were treated by both SPS and AHT under a wide range of temperatures. The microstructures and mechanical properties of the treated specimens were investigated primarily by scanning electron microscopy, electron backscatter diffraction analysis, hardness tests, and tensile tests. Despite comparable values for porosity, crystal grain size, plastic strain distribution, hardness, and yield stress, the tensile strength and ductility of the specimen treated by SPS at 400 °C (SPS400) were significantly higher than those of the specimen treated by AHT at 450 °C. Based on these results, it was determined that SPS treatment is more effective in improving the adhesion strength between the particles in cold-sprayed Cu coatings than AHT.

Ito, K.; Ogawa, K.

2014-01-01

351

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

352

A Review of NASA's Radiation-Hardened Electronics for Space Environments Project  

NASA Technical Reports Server (NTRS)

NASA's 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 requirements of NASA's Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year.

Keys, Andrew S.; Adams, James H.; Patrick, Marshall C.; Johnson, Michael A.; Cressler, John D.

2008-01-01

353

Torsion of rods of hardening material with almost-circular cross section  

Microsoft Academic Search

1.Torsion of rods of hardening materials with almost circular cross section was investigated by the perturbation method. Analytical dependences for evaluating the state of stress and strain of hardening rods are suggested.2.Good agreement between the results and known theoretical and experimental data was obtained.3.The presented solution makes it possible to predict the regions where rupture sets in and to determine

S. B. Maksimov; V. A. Lupin; A. A. Ost-semin; L. V. Maksimova

1982-01-01

354

Numerical Simulation of Stresses due to Solid State Transformations : The Simulation of Laser Hardening  

Microsoft Academic Search

The properties of many engineeringmaterialsmay be favourablymodified by application of\\u000aa suitable heat treatment. Examples are precipitation hardening, tempering and annealing.\\u000aOne of the most important treatments is the transformation hardening of steel. Steel is an\\u000aalloy of iron and carbon. At room temperature the sollubility of carbon in steel is negligible.\\u000aThe carbon seggregates as cementite (Fe3C). By heating

H. J. M. Geijselaers

2003-01-01

355

Hardening of the surface layers of a hollow billet formed by centrifugal casting  

NASA Astrophysics Data System (ADS)

One of the methods to increase the mechanical properties of steel is its hardening via the introduction of a refractory fine-grained phase into a melt. A method of fabrication of a tube blank by centrifugal casting accompanied by hardening with a refractory phase is considered. The introduction of fine tungsten and silicon carbides is shown to improve the structure of grade 15 steel and to increase the wear resistance of a tube blank made of this steel.

Chumanov, V. I.; Chumanov, I. V.; Anikeev, A. N.; Garifulin, R. R.

2010-12-01

356

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

357

An evaluation of four hardening rules of the incremental theory of plasticity  

E-print Network

AN EVALUATION OF FOUR HARDENING RULES OF THE INCREMENTAL THEORY OF PLASTICiTY A Thesis by BARRY HUNSAKER, JR. Submitted to the Craduate College of Texas ASM University in partial fulfillment of the requirement for the oegree o MASTER... OF SCIENCE December 1973 Major Subject: Aerospace Engineering AN EVALUATION OP POUR HARDENING RULES OF THE INCR MENTAL THEORY OF PLASTICITY A Thesis BARRY HUNSAKKR, JR. Approved as to style and content by: qChalrman of Cosraittee) (Head of Depar en...

Hunsaker, Barry

1973-01-01

358

A comparison of current work-hardening models used in the analysis of plastic deformations  

E-print Network

A COMPARISON OF CURRENT WORK-HARDENING MODELS USED IN THE ANALYSIS OF PLASTIC DEFORMATIONS A Thesis by DAVID KENNETH VAUGHAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1973 Major Subject: Aerospace Engineering A COMPARISON OF CURRENT WORK-HARDENING MODELS USED IN THE ANALYSIS OF PLASTIC DEFORMATIONS A Thesis by DAVID KENNETH VAUGHAN Approved as to style and content by: (Chairman...

Vaughn, David Kenneth

1973-01-01

359

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

360

An integrated process for modelling of precipitation hardening and springback in creep age-forming  

Microsoft Academic Search

Creep age-forming (CAF) process has been developed and used to manufacture complex-shaped panel components in aerospace applications. CAF is based on the complex combination of stress relaxation, creep and age hardening. The aim of this paper is to introduce an integrated technique to model stress–relaxation, creep deformation, precipitate hardening and springback in a CAF process. Firstly, a new set of

J. Lin; K. C. Ho; T. A. Dean

2006-01-01

361

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

362

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

363

High density radiation hardened FeRAMs on a 130 nm CMOS\\/FRAM process  

Microsoft Academic Search

Using hardened-by-design techniques previously demonstrated on a 1-kbit prototype 0.35-micron ferroelectric semiconductor memory, an 8-kbit FeRAM memory segment has been designed for fabrication on a Texas Instruments 130nm commercial CMOS\\/FRAM process. The 8-kbit segment can be arrayed to provide radiation hardened ferroelectric memory densities up to 64 Mbit with reasonable chip sizes and radiation hardness vastly superior to that of

David A. Kamp; Alan D. DeVilbiss; Gerald R. Haag; Kirk E. Russell; Gary F. Derbenwick

2005-01-01

364

Heat and cold acclimation in helium-cold hypothermia in the hamster.  

NASA Technical Reports Server (NTRS)

A study was made of the effects of acclimation of hamsters to high (34-35 C) and low (4-5 C) temperatures for periods up to 6 weeks on the induction of hypothermia in hamsters. Hypothermia was achieved by exposing hamsters to a helox mixture of 80% helium and 20% oxygen at 0 C. Hypothermic induction was most rapid (2-3 hr) in heat-acclimated hamsters and slowest (6-12 hr) in cold-acclimated hamsters. The induction period was intermediate (5-8 hr) in room temperature nonacclimated animals (controls). Survival time in hypothermia was relatable to previous temperature acclimations. The hypothesis that thermogenesis in cold-acclimated hamsters would accentuate resistance to induction of hypothermia was substantiated.

Musacchia, X. J.

1972-01-01

365

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

366

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

367

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.

368

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.

369

Adaptive response to cold temperatures in Vibrio vulnificus.  

PubMed

The effectiveness of rapid chilling or freezing of oysters to reduce Vibrio vulnificus levels in shellfish may be compromised by product handling procedures that permit cold adaptation. When a V. vulnificus culture was shifted from 35 degrees C to 6 degrees C conditions, it underwent transition to a non-culturable state. Cells adapted to 15 degrees C prior to change to 6 degrees C condition, however, remain viable and culturable. In addition, cultures adapted to 15 degrees C were able to survive better upon freezing at -78 degrees C compared with cultures frozen directly from 35 degrees C. Inhibition of protein synthesis by addition of chloramphenicol in a V. vulnificus culture immediately prior to the exposure to the adaptive temperature eliminated inducible cold tolerance. These results suggest that cold-adaptive "protective" proteins may enhance survival and tolerance at cold temperatures. In addition, removal of iron from the growth medium by adding 2,2'-Dipyridyl prior to cold adaptation decreased the viability by approximately 2 logarithm levels. This suggests that iron plays an important role in adaptation at cold temperatures. Analysis of total cellular proteins on an SDS polyacrylamide gel electrophoresis, labeled with 35S-methionine during exposure at 15 degrees C, showed elevated expressions of a 6-kDa and a 40-kDa protein and decreased expression of an 80-kDa protein. These results suggest that, for V. vulnificus, survival and tolerance at cold temperatures could be due to the expression of cold-adaptive proteins other than previously documented major cold shock proteins such as CS7.4 and CsdA. In this study, for the first time we have shown that exposure to an intermediate cold temperature (15 degrees C) causes a cold adaptive response, helping this pathogen remain in culturable state when exposed to a much colder temperature (6 degrees C). This adaptive nature to cold temperatures could be important for shellfish industry efforts to reduce the risk of V. vulnificus infection from consuming raw oysters. PMID:9922468

Bryan, P J; Steffan, R J; DePaola, A; Foster, J W; Bej, A K

1999-03-01

370

Comparison of beam-hardening and K-edge filters for imaging barium and iodine during fluoroscopy.  

PubMed

This study investigated the dose reduction performance of several beam-hardening and K-edge filter materials for the imaging of barium or iodine during fluoroscopy. A computer model was developed to simulate the effect of added filtration on entrance exposure rate (Xp), integral dose rate (Di), contrast (C), signal to noise ratio (SNR), imaging performance per dose (SNR2/Di), and tube load. The model incorporated the response characteristics, in both manual and automatic control modes of operation, of fluoroscopic systems to increasing or decreasing x-ray intensity at the input of the image intensifier. Input parameters to the computer model included choice of filter material and thickness, a barium or iodine test object, tube potential, phantom thickness, a CsI input phosphor, and a set of algorithms for controlling the fluoroscopic system. In all cases, the performance of systems with added filtration was judged with respect to a reference system operating under comparable conditions. In general, either beam-hardening or K-edge filters provided a significant reduction in entrance exposure and integral dose rates, but with an attendant increase in tube load. For a fluoroscopic system constrained to follow a representative automatic brightness control algorithm, added filtration provided a reduction in entrance exposure and integral dose rates for all phantom or uniformly distributed barium thickness. However, the imaging performance per dose, in some cases, decreased rapidly and was less than that of the reference system at large thicknesses. Only as change in the algorithm controlling the kVcp and mA operating points on the fluoroscopic system provided an imaging performance per dose greater than the reference system's at large thicknesses. The practical implementation of adding filtration to fluoroscopic systems is most simply accomplished with beam-hardening filters rather than K-edge filters. However, the systems with K-edge added filtration can provide slightly better performance when used over a limited range of phantom thicknesses such as the range normally associated with pediatric patients. PMID:8164575

Gagne, R M; Quinn, P W; Jennings, R J

1994-01-01

371

Roller Burnishing - A Cold Working Tool to Reduce Weld Induced Residual Stress  

SciTech Connect

The possibility of stress corrosion cracking (SCC) in regions of tensile residual stress introduced by weld deposited material has been a concern where environmental effects can reduce component life. Roller burnishing, a form of mechanical cold-working, has been considered as a means of providing for residual stress state improvements. This paper provides a computational evaluation of the roller burnishing process to address the permanent deformation needed to introduce a desirable residual stress state. The analysis uses a series of incrementally applied pressure loadings and finite element methodology to simulate the behavior of a roller burnishing tool. Various magnitudes of applied pressure loadings coupled with different size plates and boundary conditions are examined to assess the degree and depth of the residual compressive stress state after cold working. Both kinematic and isotropic hardening laws are evaluated.

John Martin

2002-02-19

372

Investigation of Clusters in Medium Carbon Secondary Hardening Ultra-high-strength Steel After Hardening and Aging Treatments  

NASA Astrophysics Data System (ADS)

Clusters, containing between 10 and 1000 atoms, have been investigated in a martensitic secondary hardening ultra-high-strength steel austenitized at 1173 K (900 °C) for 1 hour and tempered at either 768 K or 783 K (495 °C or 510 °C) for 4 or 8 hours using 3D atom probe. The presence of clusters was unambiguously established by comparing the observed spatial distribution of the different alloying elements against the corresponding distribution expected for a random solid solution. Maximum separation envelope method has been used for delineating the clusters from the surrounding "matrix." Statistical analysis was used extensively for size and composition analyses of the clusters. The clusters were found to constitute a significant fraction accounting for between 1.14 and 2.53 vol pct of the microstructure. On the average, the clusters in the 783 K (510 °C) tempered sample were coarser by ~65 pct, with an average diameter of 2.26 nm, relative to the other samples. In all samples, about 85 to 90 pct of the clusters have size less than 2 nm. The percentage frequency histograms for carbon content of the clusters in 768 K and 783 K (495 °C and 510 °C) tempered samples revealed that the distribution shifts toward higher carbon content when the tempering temperature is higher. It is likely that the presence of these clusters exerts considerable influence on the strength and fracture toughness of the steel.

Veerababu, R.; Balamuralikrishnan, R.; Muraleedharan, K.; Srinivas, M.

2015-03-01

373

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

374

Hot Planet - Cold Comfort  

NSDL National Science Digital Library

This page features videos from the "Hot Planet- Cold Comfort" television episode, related website articles and a student activity. The videos explore how the Gulf Stream conveyor belt may shut down; how Arctic river runoff and Alaskan glacial melt are freshening the oceans; and how ocean sediments and ice cores are being studied to understand the Little Ice Age. The videos total approximately one hour in length. The website articles explore the Little Ice Age; how the Arctic functions as a global thermostat, affecting global weather patterns; and great moments in climate change. The student activity is about light absorbtion. The site also contains a challenge activity to find details in a painting that depict Little Ice Age living conditions.

375

Structure and strain hardening of low stacking fault energy FCC alloys at large strains  

NASA Astrophysics Data System (ADS)

Structure and strain hardening of alpha-brass and two Co-Ni based superalloys, MP35N and AEREX350, were investigated. Constant true strain rate simple compression tests to large strains conducted on annealed, polycrystalline samples of alpha-brass, MP35N and AEREX350 alloys, revealed a four-stage hardening response in these materials, distinctly different from that observed in higher SFE fcc materials, such as copper. In each stage, microstructure was studied using optical microscopy and TEM. It was shown that deformation twinning played a decisive role in hardening response of the low SFE materials used in this study. At high strains, some localization in the form of grain-scale shear bands was observed. Although formation of these shear bands had no detectable effect on the macroscopic strain hardening rate, it did correlate with a marked change in texture evolution. Based on observations, a physical description of the microstructural phenomena responsible for the various strain hardening stages observed in low SFE fcc alloys is presented. A significant decrease in the hardening rate of ultra-fine MP35N alloy (1 mum grain size) was observed at moderate to high strains. TEM studies showed that this behavior correlated with the lack of extensive twinning in the structure, confirming the critical role of deformation twinning in hardening response of the alloy of larger grain size. Deformed MP35N alloy could be further strengthened by heat treating at 593sp°C for four hours. This secondary hardening phenomenon together with the high temperature hardening response of MP35N was investigated. A model based on segregation of solute atoms to stacking faults was proposed to account for the observations. TEM studies showed that the major strengthening phase in the solution treated and aged AEREX350 alloy was gammasp' (Nisb3Al,Ti) with L1sb2 structure. This phase was stable up to 1000sp°C and its growth kinetics followed the tsp{1/3} law. The work hardening rate of the aged AEREX350 alloy in simple compression significantly increased in moderate strains, compared to that of the solution treated alloy. This behavior may be related to the reduction of the stacking fault energy of the aged material caused by precipitation of the gammasp' phase.

Asgari, Sirous

1997-11-01

376

Comparative analysis of gene expression under cold acclimation, deacclimation and reacclimation in Arabidopsis.  

PubMed

Cold acclimated plants show an elevated tolerance against subsequent cold stress. Such adaptation requires alterations in gene expression as well as physiological changes. We were interested in gene expression changes at the transcriptional level during adaptation processes. The patterns of transcriptional changes associated with cold acclimation, deacclimation and reacclimation in Arabidopsis leaves were characterized using the Coldstresschip. Gene expression profiles were further analyzed by 'coexpressed gene sets' using gene set enrichment analysis (GSEA). Genes involved in signal transduction through calcium, and cascades of kinases and transcription factor genes, were distinctively induced in the early response of cold acclimation. On the other hand, genes involved in antioxidation, cell wall biogenesis and sterol synthesis were upregulated in the late response of cold acclimation. After the removal of cold, the expression patterns of most genes rapidly returned to the original states. However, photosynthetic light-harvesting complex genes and lipid metabolism-related genes stayed upregulated in cold deacclimated plants compared to non-treated plants. It is also notable that many well-known cold-inducible genes are slightly induced in reacclimation and their expression remains at relatively low levels in cold reacclimation compared to the expression during the first cold acclimation. The results in this study show the dynamic nature of gene expression occurring during cold acclimation, deacclimation and reacclimation. Our results suggest that there is a memory of cold stress and that the 'memory of cold stress' is possibly due to elevated photosynthetic efficiency, modified lipid metabolism, increased calcium signaling, pre-existing defense protein made during first cold acclimation and/or modified signal transduction from pre-existing defense protein. PMID:24494996

Byun, Youn-Jung; Koo, Mi-Young; Joo, Hye-Joon; Ha-Lee, Young-Mie; Lee, Dong-Hee

2014-10-01

377

BAE Systems Radiation Hardened SpaceWire ASIC and Roadmap  

NASA Technical Reports Server (NTRS)

An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS, technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASlC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a 4-port SpaceWire router with two local ports, dual PC1 bus interfaces, a microcontroller, 32KB of internal memory, -and a memory controller for additional external memory use. The SpaceWire ASlC is planned for use on both the Geostationary Operational Environmental Satellites (GOES)-R and the Lunar Reconnaissance Orbiter (LRO). Engineering parts have already been delivered to both programs. This paper discusses the SpaceWire protocol and those elements of it that have been built into the current SpaceWire reusable core. There are features within the core that go beyond the current standard that can be enabled or disabled by the user and these will be described. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be discussed. Optional configurations within user systems will be shown. The physical imp!ementation of the design will be described and test results from the hardware will be discussed. Finally, the BAE Systems roadmap for SpaceWire developments will be discussed, including some products already in design as well as longer term plans.

Berger, Richard; Milliser, Myrna; Kapcio, Paul; Stanley, Dan; Moser, David; Koehler, Jennifer; Rakow, Glenn; Schnurr, Richard

2006-01-01

378

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 AND REFRIGERATION EQUIPMENT By Charles Butler (Section 1), Joseph W. Slavin (Sections 1, 2, and 3), Max Patashnik

379

The status of cold fusion  

Microsoft Academic Search

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.

E. Storms

1993-01-01

380

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.

381

Effect of nitrogen and cold working on structural and mechanical behavior of Ni-free nitrogen containing austenitic stainless steels for biomedical applications.  

PubMed

This investigation deals with the evaluation of structural and mechanical behavior of deformed (10% and 20% cold work) and annealed (at 1050°C for 15 min followed by water quenching) Ni-free high nitrogen austenitic stainless steels (HNSs). The microstructure was observed by optical micrograph and the mechanical properties were determined by macrohardness and tensile tests. Both stress strain behavior and work hardening behavior were evaluated. HNSs have smaller grain size as compared to low nitrogen steels and no formation of martensite was observed after 20% cold working. Further, it was found that hardness; yield strength and ultimate tensile strength of the steels linearly increases and elongation decreased with nitrogen content and degree of cold working. The strength coefficient was observed to be higher for the high nitrogen steels; it decreased to some extent with degree of cold working. The work hardening exponent was also observed to decrease with degree of cold working. Influence of nitrogen on mechanical properties was mainly related to its effect on solid solution strengthening. X-ray diffraction analysis of annealed as well as deformed alloys further confirmed no evidence for formation of martensite or any other secondary phases. SEM fractography of the annealed and deformed samples after tensile tests indicates predominantly ductile fracture in all specimens. PMID:25492189

Talha, Mohd; Behera, C K; Sinha, O P

2015-02-01

382

Genomewide transcriptional analysis of the cold shock response in Bacillus subtilis.  

PubMed

Previous studies with two-dimensional gel electrophoresis techniques revealed that the cold shock response in Bacillus subtilis is characterized by rapid induction and accumulation of two classes of specific proteins, which have been termed cold-induced proteins (CIPs) and cold acclimatization proteins (CAPs), respectively. Only recently, the B. subtilis two-component system encoded by the desKR operon has been demonstrated to be essential for the cold-induced expression of the lipid-modifying desaturase Des, which is required for efficient cold adaptation of the membrane in the absence of isoleucine. At present, one of the most intriguing questions in this research field is whether DesKR plays a global role in cold signal perception and transduction in B. subtilis. In this report, we present the first genomewide transcriptional analysis of a cold-exposed bacterium and demonstrate that the B. subtilis two-component system DesKR exclusively controls the desaturase gene des and is not the cold-triggered regulatory system of global relevance. In addition to this, we identified a set of genes that might participate as novel players in the cold shock adaptation of B. subtilis. Two cold-induced genes, the elongation factor homolog ylaG and the sigma(L)-dependent transcriptional activator homolog yplP, have been examined by construction and analysis of deletion mutants. PMID:12399512

Beckering, Carsten L; Steil, Leif; Weber, Michael H W; Völker, Uwe; Marahiel, Mohamed A

2002-11-01

383

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

PubMed Central

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. PMID:23320142

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

2013-01-01

384

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

385

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

PubMed

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. PMID:23320142

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

2013-01-01

386

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

387

Cold Science article  

NSDL National Science Digital Library

University of Alaska scientists report that Alaskan glaciers are melting more rapidly than anticipated; an estimated 24 cubic miles of ice disappearing annually. Conditions promoting glacial growth vs. shrinking are briefly reviewed; melting is an indicator of climate change. Results confirm proposals that glacial melting is a major contributor to sea level rise; findings indicate that melting of Alaska's glaciers is making a disproportionate input.

388

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

389

Rapid Tooling Processes  

Microsoft Academic Search

Sand casting is one of several near net shape manufacturing processes. In near net shape manufacturing, multiple copies of\\u000a the product are produced by imprinting the shape of the tool or die on a suitable working material. Typically, the working\\u000a material starts out as a liquid, powder, or pliable material that is eventually solidified or hardened after being formed\\u000a by

Wanlong Wang; Henry W. Stoll; James G. Conley

390

Rapid prototyping of rapid prototyping machines  

E-print Network

Rapid prototyping tools empower individuals to create almost anything. Unfortunately, these tools are still far too expensive for personal ownership. The do-it-yourself community has responded with a slew of home-made rapid ...

Moyer, Ilan Ellison

2008-01-01

391

Aerodynamics inside a rapid compression machine  

SciTech Connect

The aerodynamics inside a rapid compression machine after the end of compression is investigated using planar laser-induced fluorescence (PLIF) of acetone. To study the effect of reaction chamber configuration on the resulting aerodynamics and temperature field, experiments are conducted and compared using a creviced piston and a flat piston under varying conditions. Results show that the flat piston design leads to significant mixing of the cold vortex with the hot core region, which causes alternate hot and cold regions inside the combustion chamber. At higher pressures, the effect of the vortex is reduced. The creviced piston head configuration is demonstrated to result in drastic reduction of the effect of the vortex. Experimental conditions are also simulated using the Star-CD computational fluid dynamics package. Computed results closely match with experimental observation. Numerical results indicate that with a flat piston design, gas velocity after compression is very high and the core region shrinks quickly due to rapid entrainment of cold gases. Whereas, for a creviced piston head design, gas velocity after compression is significantly lower and the core region remains unaffected for a long duration. As a consequence, for the flat piston, adiabatic core assumption can significantly overpredict the maximum temperature after the end of compression. For the creviced piston, the adiabatic core assumption is found to be valid even up to 100 ms after compression. This work therefore experimentally and numerically substantiates the importance of piston head design for achieving a homogeneous core region inside a rapid compression machine. (author)

Mittal, Gaurav; Sung, Chih-Jen [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)

2006-04-15

392

Structures and properties of a rapidly solidified Fe-19. 1Ni-1. 76Mn-0. 73Ti maraging alloy  

SciTech Connect

The hardening response, microstructural changes and mechanical properties of a rapidly solidified Fe-19.1Ni-1.76Mn-0.73Ti alloy have been studied and compared with those of conventionally processed alloys having similar compositions. Both alloys exhibited classical precipitation hardening behavior during aging. The strengthening precipitates are identified as needlelike, hexagonal Ni[sub 3]Ti. The prior austenite grain size of hot isostatic pressed powders is much smaller than that of conventionally processed alloys, and this enhances the homogeneity of the alloy. Preaging at above 525C for 10 minutes improves ductility dramatically without a severe loss of strength.

Kim, Sung-Joon (Korea Institute of Machinery and Metals, Changwon (Korea, Republic of)); Wayman, C.M. (Univ. of Illinois, Urbana, IL (United States))

1993-09-01

393

Optimization of cross-linking parameters during production of transglutaminase-hardened spherical multinuclear microcapsules by complex coacervation.  

PubMed

Gelatin-gum arabic spherical multinuclear microcapsules (SMMs) encapsulating peppermint oil were prepared by complex coacervation. Transglutaminase (TG) was used to harden the SMMs by complex coacervation instead of traditional reagents such as formaldehyde or glutaraldehyde. The effect of various cross-linking parameters on the hardening effectiveness of SMMs containing peppermint oil was investigated. The optimum parameters were as follows: hardening for 6h at 15 degrees C and pH 6.0 with a TG concentration of 15 U/g gelatin. Compared with formaldehyde, TG exhibits similar microcapsule hardening effectiveness. PMID:18155888

Dong, Zhi-Jian; Xia, Shu-Qin; Hua, Serenus; Hayat, Khizar; Zhang, Xiao-Ming; Xu, Shi-Ying

2008-05-01

394

Cold plasma decontamination of foods.  

PubMed

Cold plasma is a novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables. This flexible sanitizing method uses electricity and a carrier gas, such as air, oxygen, nitrogen, or helium; antimicrobial chemical agents are not required. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization process. A wide array of cold plasma systems that operate at atmospheric pressures or in low pressure treatment chambers are under development. Reductions of greater than 5 logs can be obtained for pathogens such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Effective treatment times can range from 120 s to as little as 3 s, depending on the food treated and the processing conditions. Key limitations for cold plasma are the relatively early state of technology development, the variety and complexity of the necessary equipment, and the largely unexplored impacts of cold plasma treatment on the sensory and nutritional qualities of treated foods. Also, the antimicrobial modes of action for various cold plasma systems vary depending on the type of cold plasma generated. Optimization and scale up to commercial treatment levels require a more complete understanding of these chemical processes. Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy. PMID:22149075

Niemira, Brendan A

2012-01-01

395

Two Back Stress Hardening Models in Rate Independent Rigid Plastic Deformation  

NASA Astrophysics Data System (ADS)

In the present work, the constitutive relations based on the combination of two back stresses are developed using the Armstrong-Frederick, Phillips and Ziegler’s type hardening rules. Various evolutions of the kinematic hardening parameter can be obtained by means of a simple combination of back stress rate using the rule of mixtures. Thus, a wide range of plastic deformation behavior can be depicted depending on the dominant back stress evolution. The ultimate back stress is also determined for the present combined kinematic hardening models. Since a kinematic hardening rule is assumed in the finite deformation regime, the stress rate is co-rotated with respect to the spin of substructure obtained by incorporating the plastic spin concept. A comparison of the various co-rotational rates is also included. Assuming rigid plasticity, the continuum body consists of the elastic deformation zone and the plastic deformation zone to form a hybrid finite element formulation. Then, the plastic deformation behavior is investigated under various loading conditions with an assumption of the J2 deformation theory. The plastic deformation localization turns out to be strongly dependent on the description of back stress evolution and its associated hardening parameters. The analysis for the shear deformation with fixed boundaries is carried out to examine the deformation localization behavior and the evolution of state variables.

Yun, Su-Jin

396

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

397

Age hardening by dendrite growth in a low-gold dental casting alloy.  

PubMed

Commercial low-gold dental casting alloy composed of Ag-Pd-In-Au-Zn was studied to clarify the age-hardening mechanism and related microstructural changes. The hardness of solution-treated specimen began to increase and reached the maximum value with ageing time, and then the maximum hardness value decreased by further ageing. The changes of X-ray diffraction (XRD) pattern during isothermal ageing revealed that the age hardening was not caused by phase transformation. By comparing the age-hardening curve with the changes in full-width at half-maximum of the XRD peaks at each ageing time, it was revealed that the coherency strains were formed in the Ag-rich matrix, which contributed to the hardness increase during ageing. From scanning electron microscopic observation and electron probe microanalysis, it was clarified that fine particle-like structures composed of InPd containing small amount of Zn gathered by diffusion in the Ag-rich matrix, and the coherency strains which formed during that time caused the hardness increase in the early stage of age-hardening process. The coherency strains were released by the progress of coarsening of Zn-containing InPd dendrite during further ageing, which caused the overaging in the later stage of age-hardening process. PMID:15020163

Lee, Hee-Kyung; Moon, Hi-Man; Seol, Hyo-Joung; Lee, Jung-Eun; Kim, Hyung-Il

2004-08-01

398

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

399

ON THE SPECTRAL HARDENING AT {approx}>300 keV IN SOLAR FLARES  

SciTech Connect

It has long been noted that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies {approx}>300 keV. It is now widely believed that at least in electron-dominated events, the hardening in the photon spectrum reflects an intrinsic hardening in the source electron spectrum. In this paper, we point out that a power-law spectrum of electrons with a hardening at high energies can be explained by the diffusive shock acceleration of electrons at a termination shock with a finite width. Our suggestion is based on an early analytical work by Drury et al., where the steady-state transport equation at a shock with a tanh profile was solved for a p-independent diffusion coefficient. Numerical simulations with a p-dependent diffusion coefficient show hardenings in the accelerated electron spectrum that are comparable with observations. One necessary condition for our proposed scenario to work is that high-energy electrons resonate with the inertial range of the MHD turbulence and low-energy electrons resonate with the dissipation range of the MHD turbulence at the acceleration site, and the spectrum of the dissipation range {approx}k {sup -2.7}. A {approx}k {sup -2.7} dissipation range spectrum is consistent with recent solar wind observations.

Li, G.; Kong, X.; Zank, G. [Department of Physics and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Chen, Y., E-mail: gang.li@uah.edu [Institute of Space Sciences and School of Space Sciences and Physics, Shandong University, 264209 Weihai (China)

2013-05-20

400

Zitterbewegung in Cold Atoms  

NASA Astrophysics Data System (ADS)

In condensed matter systems, the coupling between spatial and spin degrees of freedom through the spin-orbit (SO) interaction offers the possibility of manipulating the electron spin via its orbital motion. The proposal by Datta and Das [1,2] of a `spin transistor' for example, highlights the use of the SO interaction to control the electron spin via electrical means. Recently, arrangements of crossed lasers and magnetic fields have been used to trap and cool atoms in optical lattices and also to create light-induced gauge potentials [3], which mimic the SO interactions in real solids. In this work, we investigate the Zitterbewegung in cold atoms by starting from the effective SO Hamiltonian derived in Ref. [4]. Cross-dressed atoms as effective spins can provide a proper setting in which to observe this effect, as the relevant parameter range of SO strengths may be more easily attainable in this context. We find a variety of peculiar Zitterbewegung orbits in real and pseudo-spin spaces, e.g., cycloids and ellipses - all of which obtained with realistic parameters.[4pt] [1] S. Datta and B. Das, Appl. Phys. Lett. 56, 655 (1990);[0pt] [2] J. Carlos Egues, et. al., Appl. Phys. Lett. 82, 2658 (2003);[0pt] [3] Y. -J. Lin, et. al, Nature 471, 83 (2011);[0pt] [4] Jay D. Sau, et. al, PRB 83, 140510(R) (2010).

Penteado, Poliana; Egues, J. Carlos

2013-03-01

401

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.

402

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

403

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

404

Nonfreezing cold-induced injuries.  

PubMed

Non-freezing cold injury (NFCI) is the Cinderella of thermal injuries and is a clinical syndrome that occurs when tissues are exposed to cold temperatures close to freezing point for sustained periods. NFCI is insidious in onset, often difficult to recognize and problematic to treat, and yet the condition accounts for significant morbidity in both military and civilians who work in cold conditions. Consequently recognition of those at risk, limiting their exposure and the appropriate and timely use of suitable protective equipment are essential steps in trying to reduce the impact of the condition. This review addresses the issues surrounding NFCI. PMID:21465916

Imray, C H E; Richards, P; Greeves, J; Castellani, J W

2011-03-01

405

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

406

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

407

Cross breeding of Populus and its hybrids for cold resistance  

Microsoft Academic Search

Populus tomentosa was crossed with P. tremuloidis, P. grandidentata, P. alba ? P. grandidentata and P. alba ? Ulmus pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to\\u000a increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing

Dong-fang Zhang; Zhi-yi Zhang; Zhi-ti Zhu

2005-01-01

408

Rapid shallow breathing  

MedlinePLUS

Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... Shallow, rapid breathing has many possible medical causes, including: Asthma Blood clot in an artery in the lung Choking Chronic obstructive ...

409

Differential conduction of cold through barriers.  

PubMed

Despite the widespread use of ice packs in conjunction with ace bandages, padded ace bandages and compression dressings in the management of acute soft tissue trauma and sprains, the role of these barriers in the conduction of cold has not been adequately evaluated. Thermal probes were secured to both ankles of 62 healthy volunteers. The selected barrier was applied bilaterally and 500 g of chipped ice in a plastic bag was placed over the barrier on the right ankle for 30-45 minutes. A significant reduction in temperature of the right ankle was noted in all groups except in the padded ace group. The most rapid decrease in temperature was noted during the first 2 minutes of treatment. During the first minute, the surface temperature decreased an average of 22 degrees C (ace), 3.8 degrees C (dry washcloth), 5.2 degrees C (no barrier) and 5.4 degrees C (damp washcloth). After 10 minutes, the mean rate of cooling was 0.1-0.2 degree C and was approximately the same in all four groups. The Scheffe procedure indicated three homogeneous subgroups at 30 minutes: no barrier, damp washcloth; ace, dry washcloth; and padded ace. These findings question the clinical usefulness of the application of cold over padded aces and compression dressings and the use of a damp washcloth to 'protect' the skin from frostbite. PMID:3844415

LaVelle, B E; Snyder, M

1985-01-01

410

The Cold War is over. What now?  

SciTech Connect

As you might imagine, the end of the Cold War has elicited an intense reexamination of the roles and missions of institutions such as the Los Alamos National Laboratory. During the past few years, the entire defense establishment has undergone substantial consolidation, with a concomitant decrease in support for research and development, including in areas such as materials. The defense industry is down-sizing at a rapid pace. Even universities have experienced significant funding cutbacks from the defense community. I view this as a profound time in history, bringing changes encompassing much more than just the defense world. In fact, support for science and technology is being reexamined across the board more completely than at any other time since the end of World War II.

Hecker, S.S.

1995-05-01

411

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 ...

412

Protecting Workers from Cold Stress  

MedlinePLUS

... you on cold stress hazards and prevention. • Provide engineering controls, e.g., radiant heaters. • Gradually introduce workers ... to rewarm the area unless directed by medical personnel. For Trench (Immersion) Foot: • Remove wet shoes/socks; ...

413

Prescription Drugs and Cold Medicines  

MedlinePLUS

... Cold Medicines Email Facebook Twitter What is Prescription Drug Abuse: Some medications have psychoactive (mind-altering) properties and, ... Unused Medicines: What You Should Know (FDA) Prescription Drug Abuse Learn what you can do to prevent medicine ...

414

Ferrous arrowheads and their oil quench hardening: Some early Indian evidence  

NASA Astrophysics Data System (ADS)

A wide variety of ferrous arrowheads were in use in ancient India. Several typical chemical analyses of arrowheads found from archaeological excavation carried out at Kaushambi are reported in this paper. The average carbon content of these arrowheads varied from as low as 0.1 wt.% to approximately 0.9 wt.%. Literary evidence for oil quench hardening of ferrous arrowheads, as reported in famous Sanskrit epics—the R?m?yana and the Mah?bh?rata—have been discussed in this paper. This type of quench hardening was intentionally adopted as it helped in preventing distortion and formation of quench cracks in arrowheads. The oil quench-hardened arrowheads were rubbed on stones to sharpen them, which also brought about tempering of martensite due to frictional heat.

Dube, R. K.

2008-05-01

415

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

416

Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing**  

PubMed Central

We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100–200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu. PMID:23447712

Kiener, Daniel; Kaufmann, Petra; Minor, Andrew M.

2012-01-01

417

Strong work-hardening effect in a multiphase ZrCuAlNiO alloy  

NASA Astrophysics Data System (ADS)

A bulk as-cast ZrCuAlNiO alloy consisting of Zr2Cu, B2-type ZrCu, and a small quantity of ZrCu martensite phase was prepared by copper mold casting. The multiphase alloy exhibits a remarkable work-hardening effect (??y=1196MPa, ?E =5.6GPa, and ??e=2.11%) in the cycle loading-unloading compression test and possesses the high work-hardening capacity (Hc) of 1.66 and 1.58 at strain rates of 1×10-4 and 1×10-3s-1, respectively, under continuous deformation. The strong work-hardening effect of the alloy results from the continuous transformation of the ZrCu (B2, austenite) phase into the ZrCu martensite.

Qiu, Feng; Shen, Ping; Jiang, Zhonghao; Liu, Tao; Jiang, Qichuan

2008-04-01

418

Study on laser surface transformation hardening technological control of cool rolling ball guide screw  

NASA Astrophysics Data System (ADS)

There are advantages of less working procedure and lower cost in cool rolling ball. But after convention heat treatment, because of bigger deformation, the workpiece must be corrected and finely burnish, which improves the cost and descends the precision. Because there is less deformation in laser surface transformation hardening, we use HJ-3 CO2 laser machine to study the technology of the surface phase transformation hardening of cool rolling ball guide-distance is less than 0.1, the axial beat value is less than 0.02mm, surface hardness is above HRc 60 and the average depth of hardening layer is 0.2mm. Not only is it not necessary to correct and finely grind, but also the precision of guide screw is improved.

Ren, Enyang; Chen, Tie-Li; Ling, Yu; Li, Junchang

1996-09-01

419

A study on laser surface transformation hardening technological control of cool rolling ball guide screw  

SciTech Connect

There are advantages of less working procedure and lower cost in cool rolling. But after convention heat treatment, because of bigger deformation, the workpiece must be corrected and finely burnish, which improves the cost and descends the precision. Because there is less deformation in laser surface transformation hardening, the authors use HJ-3 CO{sub 2} laser machine to study the technology of the surface phase transformation hardening of cool rolling ball, guide-distance is less than 0.1, the axial beat value is less than 0.02mm, surface hardness is above HRc 60 and the average depth of hardening layer is 0.2mm. Not only is it not necessary to correct and finely grind, but also the precision of guide screw is improved.

Ren Enyang; Chen Tieli; Ling Yu; Li Junchang [Kunming Univ. of Science and Technology (China)

1996-12-31

420

Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing.  

PubMed

We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100-200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu. PMID:23447712

Kiener, Daniel; Kaufmann, Petra; Minor, Andrew M

2012-11-01

421

Densification and strain hardening of a metallic glass under tension at room temperature.  

PubMed

The deformation of metallic glasses involves two competing processes: a disordering process involving dilatation, free volume accumulation, and softening, and a relaxation process involving diffusional ordering and densification. For metallic glasses at room temperature and under uniaxial loading, disordering usually dominates, and the glass can fail catastrophically as the softening process runs away in a localized mode. Here we demonstrate conditions where the opposite, unexpected, situation occurs: the densifying process dominates, resulting in stable plastic deformation and work hardening at room temperature. We report densification and hardening during deformation in a Zr-based glass under multiaxial loading, in a notched tensile geometry. The effect is driven by stress-enhanced diffusional relaxation, and is attended by a reduction in exothermic heat and hardening signatures similar to those observed in the classical thermal relaxation of glasses. The result is significant, stable, plastic, extensional flow in metallic glasses, which suggest a possibility of designing tough glasses based on their flow properties. PMID:24116793

Wang, Z T; Pan, J; Li, Y; Schuh, C A

2013-09-27

422

Transient radiation hardened CMOS (complementary metal oxide semiconductor) operational amplifiers. Master's thesis  

SciTech Connect

General strategies are developed for designing radiation hardened bulk and silicon on insulator (SOI) complementary metal oxide semiconductor (CMOS) operational amplifiers. Comparisons are made between each technology concerning photocurrent mechanisms and the inherent advantages of SOI CMOS. Methods are presented for analysing circuit designs and minimizing the net photocurrent responses. Analysis is performed on standard operational amplifier circuits and subcircuits to demonstrate the usefulness of these methods. Radiation hardening topics discussed include superior radiation hardened topologies, photocurrent compensation and its limitations, and methods to ensure a preferred direction of photocurrent response. Several operational amplifier subcircuits are compared for their hardness characteristics. Folded cascode and three-stage operational amplifiers were fabricated on an SOI CMOS test chip supported by Texas Instruments, Incorporated. At the time of publication, the circuit operation was verified but radiation data were not yet available.

Trombley, G.J.

1989-01-01

423

Quantification of age hardening in maraging steels and an Ni-base superalloy  

SciTech Connect

Age hardening process in metallic alloys due to precipitation can be quantified using phase transformation theories. Two ageing stages are of particular interest, for both theory and practice. The early stage of precipitation hardening is under the description of the Johnson-Mehl-Avrami equation. Wilson has recently provided a detailed theoretical analysis for early stages of ageing. Wilson successfully used equations in the quantification of early and over-ageing stages of hardening in an Fe-12Ni-6Mn maraging-type alloy. In the present work, these were applied to further alloys. All the hardness data were taken from published literature. Original references should be consulted for details of materials, testing and characterization.

Sha, W.

2000-02-01

424

Electron microscopy observations of twin-twin intersections in a particle hardened copper-titanium alloy  

SciTech Connect

The authors have recently reported electron microscopy (CTEM and HREM) observations of mechanical twinning in age hardened copper-titanium alloys containing a fine dispersion of the metastable Cu{sub 4}Ti ({beta}{prime}; D1{sub a}) phase ({approx}15 vol%). These particle hardened alloys are known to twin profusely and it has been suggested that single crystals of Cu-Ti-Al alloys containing coherent Cu{sub 4}Ti (D1{sub a}) particles yield by twinning at the onset of plastic flow. In this short paper conventional (CTEM) and high-resolution (HREM) electron microscopy observations of twin/twin intersections in the precipitation hardened two-phase copper-titanium alloys are reported. These results will suggest that the mechanisms governing shear accommodation in obstacle twins remain to be elucidated.

Radetic, T.; Soffa, W.A. [Univ. of Pittsburgh, PA (United States). Dept. of Materials Science and Engineering] [Univ. of Pittsburgh, PA (United States). Dept. of Materials Science and Engineering; Radmilovic, V. [Univ. of Belgrade (Yugoslavia). Dept. of Physical Metallurgy] [Univ. of Belgrade (Yugoslavia). Dept. of Physical Metallurgy

1999-03-05

425

Effects of dispersion particle agents on the hardening of V-4Cr-4Ti alloys  

NASA Astrophysics Data System (ADS)

In the mechanical alloying (MA) of vanadium alloys, various particles can have a combined dispersion-strengthening effect. The nature, especially the thermal stability, of the dispersion particle agents can play an important role for the strengthening at elevated temperatures. In order to optimize the particle species in dispersion strengthened vanadium alloys for high temperature application, this study focuses on the hardening of V-4Cr-4Ti alloy by different dispersion particle agents such as yttrium compounds and carbides. Alloying degrees, grain sizes, densifications and solid solution of interstitial impurities are compared for better understanding the hardening due to nano-particles. Though the dissolution of carbides may be poor, it has been found that the hardening due to Ti3SiC2 addition is efficient and most stable after annealing at high temperature up to 1723 K.

Zheng, P. F.; Chen, J. M.; Nagasaka, T.; Muroga, T.; Zhao, J. J.; Xu, Z. Y.; Li, C. H.; Fu, H. Y.; Chen, H.; Duan, X. R.

2014-12-01

426

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

427

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

428

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

429

COLD-SAT dynamic model  

Microsoft Academic Search

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

Neil S. Adams; Gary Bollenbacher

1992-01-01

430

Reexamining the Cold Conveyor Belt  

Microsoft Academic Search

Despite the popularity of the conveyor-belt model for portraying the airflow through midlatitude cyclones, questions arise as to the path of the cold conveyor belt, the lower-tropospheric airflow poleward of and underneath the warm front. Some studies, beginning with Carlson's analysis of the eastern U.S. cyclone of 5 December 1977, depict the cold conveyor belt moving westward, reaching the northwest

David M. Schultz

2001-01-01

431

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

432

Molecular basis of cold adaptation.  

PubMed Central

Cold-adapted, or psychrophilic, organisms are able to thrive at low temperatures in permanently cold environments, which in fact characterize the greatest proportion of our planet. Psychrophiles include both prokaryotic and eukaryotic organisms and thus represent a significant proportion of the living world. These organisms produce cold-evolved enzymes that are partially able to cope with the reduction in chemical reaction rates induced by low temperatures. As a rule, cold-active enzymes display a high catalytic efficiency, associated however, with a low thermal stability. In most cases, the adaptation to cold is achieved through a reduction in the activation energy that possibly originates from an increased flexibility of either a selected area or of the overall protein structure. This enhanced plasticity seems in turn to be induced by the weak thermal stability of psychrophilic enzymes. The adaptation strategies are beginning to be understood thanks to recent advances in the elucidation of the molecular characteristics of cold-adapted enzymes derived from X-ray crystallography, protein engineering and biophysical methods. Psychrophilic organisms and their enzymes have, in recent years, increasingly attracted the attention of the scientific community due to their peculiar properties that render them particularly useful in investigating the possible relationship existing between stability, flexibility and specific activity and as valuable tools for biotechnological purposes. PMID:12171655

D'Amico, Salvino; Claverie, Paule; Collins, Tony; Georlette, Daphné; Gratia, Emmanuelle; Hoyoux, Anne; Meuwis, Marie-Alice; Feller, Georges; Gerday, Charles

2002-01-01

433

Mechanical properties of friction stir welded Al alloys with different hardening mechanisms  

Microsoft Academic Search

The mechanical properties of precipitation hardened Al 6061-T651 and Al 7075-T6 and strain hardened Al 5083-H32, friction\\u000a stir welded with various welding parameters, were examined in the present study. 4 mm thick Al 6061-T651, Al 7075-T6, and\\u000a Al 5083-H32 alloy plates were used for friction stir welding (FSW) with rotating speed varied from 1000 to 2500 rpm (rotation\\u000a per minute)

Sunggon Lim; Sangshik Kim; Chang-Gil Lee; Sung Joon Kim

2005-01-01

434

Conditions for pseudo strain-hardening in fiber reinforced brittle matrix composites  

SciTech Connect

Apart from imparting increased fracture toughness, one of the useful purposes of reinforcing brittle matrices with fibers is to create enhanced composite strain capacity. This paper reviews the conditions underwhich such a composite will exhibit the pseudo strain-hardening phenomenon. The presentation is given in a unified manner for both continuous aligned and discontinuous random fiber composites. It is demonstrated that pseudo strain hardening can be practically designed for both gills of composites by proper tailoring of material structures. 18 refs., 8 figs., 2 tabs.

Li, V.C.; Wu, H.W. [Univ. of Michigan, Ann Arbor, MI (United States)

1992-08-01

435

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

436

On the Decomposition of Martensite During Bake Hardening of Thermomechanically Processed TRIP Steels  

SciTech Connect

Thermomechanically processed (TMP) CMnSi transformation-induced plasticity (TRIP) steels with and without additions of Nb, Mo, or Al were subjected to prestraining and bake hardening. Atom probe tomography (APT) revealed the presence of fine C-rich clusters in the martensite of all studied steels after the thermomechanical processing. After bake hardening, the formation of iron carbides, containing from 25 to 90 at. pct C, was observed. The evolution of iron carbide compositions was independent of steel composition and was a function of carbide size.

Pereloma, E. V. [University of Wollongong, Wollongong, Australia; Miller, Michael K [ORNL; Timokhina, I. B. [Monash University, Australia

2008-01-01

437

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

438

Electron microscopy observations of deformation twinning in a precipitation hardened copper-titanium alloy  

SciTech Connect

Copper-titanium alloys in the range 1 to 5 wt% titanium can exhibit properties comparable to the well-known Cu-Be alloy series after suitable heat treatment. Age hardened Cu-Ti alloys represent a potentially important substitute for the conventional high-strength Cu-Be materials in a variety of applications, particularly in the electronics industry. In this paper the preliminary results of conventional electron microscopy (CTEM) and high-resolution electron microscopy (HREM) studies of the fine-scale structure of the mechanical twins which form in particle hardened copper-titanium alloys are reported.

Radetic, T.; Soffa, W.A. [Univ. of Pittsburgh, PA (United States). Dept. of Materials Science and Engineering] [Univ. of Pittsburgh, PA (United States). Dept. of Materials Science and Engineering; Radmilovic, V. [Univ. of Belgrade (Yugoslavia). Dept. of Physical Metallurgy] [Univ. of Belgrade (Yugoslavia). Dept. of Physical Metallurgy

1996-12-15

439

Effects of pre-strain and baking parameters on the microstructure and bake-hardening behavior of dual-phase steel  

NASA Astrophysics Data System (ADS)

In a typical process, C-Mn steel was annealed at 800°C for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening (BH) values were determined as a function of pre-strain, baking temperature, and baking time. The influences of pre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300°C. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.

Kuang, Chun-fu; Zhang, Shen-gen; Li, Jun; Wang, Jian; Liu, Hua-fei

2014-08-01

440

Ageing behaviour of an Fe-20Ni-1.8Mn-1.6Ti-0.59Al (wt%) maraging alloy: clustering, precipitation and hardening  

SciTech Connect

Changes in the solute distribution as well as the evolution of precipitation, microstructure and mechanical properties have been studied in an experimental maraging Fe-20Ni-1.8Mn-1.5Ti-0.59Al (wt%) alloy during ageing at 550 deg C. An initial hardening reaction within 5 s is reported, which is remarkable in terms of extent and rapidity. This strengthening was caused by the formation of complex multi-component atomic co-clusters containing primarily Ni-Ti-Al as well as some Mn. This cluster strengthened condition produced the optimum toughness observed throughout the ageing sequence. After 60 s ageing, the appearance of discrete precipitation of needle-shaped {eta}-Ni{sub 3}Ti particles was associated with a second rise in hardness towards an eventual peak at 600 s. This precipitation hardening was accompanied by an increase in tensile strength and a decrease in ductility. A reverse transformation of martensite to austenite occurs progressively during ageing and this contributes to the initial and secondary softening.

Pereloma, E.V. [School of Physics and Materials Engineering, Monash University, Vic. 3800 (Australia)]. E-mail: elena.pereloma@spme.monash.edu.au; Shekhter, A. [School of Physics and Materials Engineering, Monash University, Vic. 3800 (Australia); Miller, M.K. [Oak Ridge National Laboratory, Metals and Ceramics Division, Tennessee (United States); Ringer, S.P. [Australian Key Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia)

2004-11-08

441

Cold War Entanglements of Social ANDY BYFORD  

E-print Network

in particular) and political agents of all hues in post-war America. In this context `the Cold War' is madeREVIEW Cold War Entanglements of Social Science ANDY BYFORD MLAC, Durham University, UK Cold War.00. The Cold War era the three decades between the end of the Second World War and the end of the Vietnam War

Solovey, Mark

442

A search for the Mpemba effect: When hot water freezes faster then cold water  

Microsoft Academic Search

An explanation for why hot water will sometime freeze more rapidly than cold\\u000awater is offered. Two specimens of water from the same source will often have\\u000adifferent spontaneous freezing temperatures; that is, the temperature at which\\u000afreezing begins. When both specimens supercool and the spontaneous freezing\\u000atemperature of the hot water is higher than that of the cold water,

James D. Brownridge

2010-01-01

443

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

444

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

445

EDITORIAL: Cold Quantum GasesEditorial: Cold Quantum Gases  

NASA Astrophysics Data System (ADS)

This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include: bulletBose--Einstein condensation bulletFermi degenerate gases bulletCharacterization and manipulation of quantum gases bulletCoherent and nonlinear cold matter wave optics bulletNew schemes for laser cooling bulletCoherent cold molecular gases bulletUltra-precise atomic clocks bulletApplications of cold quantum gases to metrology and spectroscopy bulletApplications of cold quantum gases to quantum computing bulletNanoprobes and nanolithography. This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam. The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by the Dutch Foundation for Fundamental Research on Matter (FOM) and by the Dutch Gelderland province. We thank all these sponsors and the members of the International Programme Committee for making the Workshop such a success. At this point we take the opportunity to express our gratitude to both authors and reviewers, for their efforts in preparing and ensuring the high quality of the papers in this special issue. Wim Vassen Vrije Universiteit, Amsterdam Andreas Hemmerich Universität Hamburg Ennio Arimondo Università di Pisa Guest Editors International Programme Committee A Aspect Orsay, France E Cornell Boulder, USA W Ertmer Hannover, Germany T W Haensch Munich, Germany A Hemmerich Hamburg, Germany W Hogervorst Amsterdam, The Netherlands D Kleppner Cambridge, USA C Salomon Paris, France G V Shlyapnikov Amsterdam, Paris, Moscow S Stringari Trento, Italy W Vassen Amsterdam, The Netherlands J T M Walraven Amsterdam, The Netherlands