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1

Rapid cold-hardening increases membrane fluidity and cold tolerance of insect cells.  

PubMed

The rapid cold-hardening (RCH) response not only confers dramatic protection against cold-shock (non-freezing) injury, but also "instantaneously" enhances organismal performance. Since cold-shock injury is associated with damage to the cell membrane, we investigated the relationship between RCH and changes in cold tolerance and membrane fluidity at the cellular level. None of the adult flies (Sarcophaga bullata) in the cold-shocked treatment group survived direct transfer to -8 degrees C for 2 h; in contrast, 64.5% of flies in the RCH group survived exposure to -8 degrees C. Differences between the treatment groups also were reflected at the cellular level; only 21.3% of fat body cells in the cold-shocked group survived compared to 68.5% in the RCH group. Using 31P solid-state NMR spectroscopy, we determined that membrane fluidity increased concurrently with rapid cold-hardening of fat body cells. This result suggests that membrane characteristics may be modified very rapidly to protect cells against cold-shock injury. PMID:16626678

Lee, Richard E; Damodaran, Krishnan; Yi, Shu-Xia; Lorigan, Gary A

2006-06-01

2

Effect of Rapid Cold Hardening on the Cold Tolerance of the Larvae of the Rice Stem Borer, Chilo suppressalis (Walker)  

Microsoft Academic Search

The effects of rapid cold hardening (RCH) on the cold tolerance of the last instar larvae of Chilo suppressalis (Walker) were evaluated for the first time. The discriminating temperature, induction, detection, duration and extent of RCH of the larvae in the laboratory were tested, and the supercooling points (SCPs) and the contents of water and lipid of the larvae after

Cheng-kui QIANG; Yu-zhou DU; Ling-ya YU; Ya-dong CUI; Fu-shan ZHENG; Ming-xing LU

2008-01-01

3

Rapid cold-hardening blocks cold-induced apoptosis by inhibiting the activation of pro-caspases in the flesh fly Sarcophaga crassipalpis  

Microsoft Academic Search

Apoptosis plays important roles in the selective elimination of sub-lethally damaged cells due to various environmental stresses.\\u000a The rapid cold-hardening (RCH) response protects insects from the otherwise lethal consequences of injury due to cold-shock.\\u000a We recently demonstrated that cold shock induces apoptotic cell death in insects and that RCH functions to specifically block\\u000a cold-shock-induced apoptosis. In the present study we

Shu-Xia YiRichard; Richard E. Lee

2011-01-01

4

Pre-adapted to the maritime Antarctic?--rapid cold hardening of the midge, Eretmoptera murphyi.  

PubMed

During the 1960s, the midge, Eretmoptera murphyi, was transferred from sub-Antarctic South Georgia (55°S 37°W) where it is endemic to a single location on maritime Antarctic Signy Island (60°S 45°W). Its distribution has since expanded considerably, suggesting that it is pre-adapted to the more severe conditions further south. To test one aspect of the level of its pre-adaptation, the rapid cold hardening (RCH) response in this species was investigated. When juvenile (L1-L2) and mature (L3-L4) larvae of E. murphyi were directly exposed to progressively lower temperatures for 8h, they exhibited Discriminating Temperatures (DTemp, temperature at which there is 10-20% survival of exposed individuals) of -11.5 and -12.5°C, respectively. The mean SCP was above -7.5°C in both larval groups, confirming the finding of previous studies that this species is freeze-tolerant. Following gradual cooling (0.2°Cmin(-1)), survival was significantly greater at the DTemp in both larval groups. The response was strong, lowering the lower lethal temperature (LLT) by up to 6.5°C and maintaining survival above 80% for at least 22h at the DTemp. RCH was also exhibited during the cooling phase of an ecologically relevant thermoperiodic cycle (+4°C to -3°C). Mechanistically, the response did not affect freezing, with no alteration in the supercooling point (SCP) found following gradual cooling, and was not induced while the organism was in a frozen state. These results are discussed in light of E. murphyi's pre-adaptation to conditions on Signy Island and its potential to colonize regions further south in the maritime Antarctic. PMID:22684111

Everatt, M J; Worland, M R; Bale, J S; Convey, P; Hayward, S A L

2012-06-07

5

Relationship between rapid cold-hardening and cold acclimation in the eggs of the yellow-spotted longicorn beetle, Psacothea hilaris.  

PubMed

Rapid cold-hardening (RCH) and cold acclimation (ACC) were examined in eggs of the yellow-spotted longicorn beetle, Psacothea hilaris (Pascoe) (Coleoptera: Cerambycidae). When eggs incubated at 25 degrees C were transferred directly to conditions of -22 degrees C for 2h, less than 30% survived, whereas exposure to 0 degrees C for 4h prior to transfer to -22 degrees C increased survival to nearly 60%. The rapidly enhanced cold tolerance (RCH) was transient and lost rapidly after 1h at 25 degrees C. Incubation at 15.5 degrees C for 9 days (ACC) also enhanced cold tolerance. Comparison of the cold tolerance of non-treated eggs and eggs pre-treated to give RCH, ACC, or ACC+RCH allowed the relationship between the two hardening processes to be determined. At a mild subzero temperature (-10 degrees C) an RCH effect was not detected, whereas only RCH is effective at the severest subzero temperature just above the SCP (-26 degrees C). At intermediate temperatures (-16, -22 and -25 degrees C), ACC and RCH enhanced survival in combination. Therefore, the two hardening processes have different physiological bases but operate concomitantly over a wide temperature range. PMID:17628587

Shintani, Yoshinori; Ishikawa, Yukio

2007-06-09

6

Rapid cold hardening improves recovery of ion homeostasis and chill coma recovery time in the migratory locust, Locusta migratoria.  

PubMed

Chill tolerance of insects is defined as the ability to tolerate low temperature under circumstances not involving freezing of intracellular or extracellular fluids. For many insects chill tolerance is crucial for their ability to persist in cold environments and mounting evidence indicates that chill tolerance is associated with the ability to maintain ion and water homeostasis, thereby ensuring muscular function and preventing chill injury at low temperature. The present study describes the relationship between muscle and haemolymph ion homeostasis and time to regain posture following cold shock (CS, 2 h at -4°C) in the chill-susceptible locust Locusta migratoria. This relationship was examined in animals with and without a prior rapid cold-hardening treatment (RCH, 2 h at 0°C) to investigate the physiological underpinnings of RCH. CS elicited a doubling of haemolymph [K(+)] and this disturbance was greater in locusts pre-exposed to RCH. Recovery of ion homeostasis was, however, markedly faster in RCH-treated animals, which correlated well with whole-organism performance as hardened individuals regained posture faster than non-hardened individuals following CS. The present study indicates that loss and recovery of muscular function are associated with the resting membrane potential of excitable membranes as attested by the changes in the equilibrium potential for K(+) (EK) following CS. Both hardened and non-hardened animals regained movement once K(+) homeostasis had recovered to a fixed level (EK?-41 mV). RCH is therefore not associated with altered sensitivity to ion disturbance but instead is correlated to a faster recovery of haemolymph [K(+)]. PMID:23348947

Findsen, Anders; Andersen, Jonas Lembcke; Calderon, Sofia; Overgaard, Johannes

2013-01-24

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

Cold tolerance including rapid cold-hardening and inoculative freezing of fall migrant monarch butterflies in Ohio  

Microsoft Academic Search

Migrants of the eastern North American population of the monarch butterfly, Danaus plexippus, are often subjected to subzero temperatures, heavy dews and frost in late September and October during the autumn migration to overwintering sites in Mexico. Adults of this generation had the capacity to rapidly increase their cold-hardiness. A chilling period of 1 h at +4OC before exposure to

KIRK J. LARSEN; R LEEJR

1994-01-01

9

Rapid cold-hardening blocks cold-induced apoptosis by inhibiting the activation of pro-caspases in the flesh fly Sarcophaga crassipalpis.  

PubMed

Apoptosis plays important roles in the selective elimination of sub-lethally damaged cells due to various environmental stresses. The rapid cold-hardening (RCH) response protects insects from the otherwise lethal consequences of injury due to cold-shock. We recently demonstrated that cold shock induces apoptotic cell death in insects and that RCH functions to specifically block cold-shock-induced apoptosis. In the present study we used isolated fat body, midgut, muscle, and Malpighian tubules from adult flesh flies Sarcophaga crassipalpis to test the following hypotheses: (1) cold-induced apoptosis varies among different tissues and (2) RCH blocks the apoptotic pathway by preventing the activation of pro-caspases. Cold-shock induced substantial amounts of apoptotic cell death that matched with tissue damage as determined using vital dyes. RCH treatment significantly reduced apoptotic cell death in all tested tissues. Caspase-3 (executioner) activity was 2-3 times higher in the cold- and heat-shocked groups than in control and RCH groups. Likewise, the activity of caspase-9 (initiator) showed a similar trend as for caspase-3 in all tissues but midgut. In addition, cold-shock and heat-shock treatments also increased caspase-2 activity 2-3 folds in both soluble and membrane fractions of fat body and muscle extracts compared to controls. PMID:21197578

Yi, Shu-Xia; Lee, Richard E

2011-03-01

10

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

PubMed

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

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

2012-08-16

11

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

2011-08-22

12

Enhancement of supercooling capacity and survival by cold acclimation, rapid cold and heat hardening in Spodoptera exigua.  

PubMed

Insects can increase their resistance to cold stress by prior exposure to non-lethal cold temperatures. Here, we investigated the supercooling capacity and survival of eggs, 3rd and 5th instar larvae, and pupae of Spodoptera exigua (Lepidoptera: Noctuidae) during CA, and responses to various pre-treatment protocols, including constant temperatures, thermoperiods, and RCH, RHH, RCH+RHH and RHH+RCH combined with thermoperiods. Only acclimated eggs demonstrated a significant decrease in SCP, from -20.7±0.3 to -22.9±0.3°C, among all experimental groups compared to non-acclimated stages. Survival increased by 17.5% for eggs, 40.0% and 13.3% for 3rd and 5th instar larvae, and by 20.0% for pupae after CA. Compared to controls, survival of eggs under the conditions of thermoperiod (5:15°C), thermoperiod (5:15°C)+RHH, and thermoperiod (5:15, 10:20, and 15:25°C)+RCH significantly increased. In addition, survival of 3rd and 5th instar larvae and pupae increased under the conditions of thermoperiod (5:15°C) and thermoperiod (5:15°C)+RCH, possibly due to the induction of heat shock proteins or cryoprotectants. However, the pre-treatments of thermoperiod+RCH+RHH and thermoperiod+RHH+RCH did not significantly enhance survival of any developmental stage. These adaptive responses may allow S. exigua to enhance supercooling capacity and survival in response to seasonal or unexpected diurnal decreases in environmental temperatures. PMID:21878325

Zheng, Xialin; Cheng, Wenjie; Wang, Xiaoping; Lei, Chaoliang

2011-08-23

13

Responses of the bed bug, Cimex lectularius, to temperature extremes and dehydration: levels of tolerance, rapid cold hardening and expression of heat shock proteins.  

PubMed

This study of the bed bug, Cimex lectularius, examines tolerance of adult females to extremes in temperature and loss of body water. Although the supercooling point (SCP) of the bed bugs was approximately -20 degrees C, all were killed by a direct 1 h exposure to -16 degrees C. Thus, this species cannot tolerate freezing and is killed at temperatures well above its SCP. Neither cold acclimation at 4 degrees C for 2 weeks nor dehydration (15% loss of water content) enhanced cold tolerance. However, bed bugs have the capacity for rapid cold hardening, i.e. a 1-h exposure to 0 degrees C improved their subsequent tolerance of -14 and -16 degrees C. In response to heat stress, fewer than 20% of the bugs survived a 1-h exposure to 46 degrees C, and nearly all were killed at 48 degrees C. Dehydration, heat acclimation at 30 degrees C for 2 weeks and rapid heat hardening at 37 degrees C for 1 h all failed to improve heat tolerance. Expression of the mRNAs encoding two heat shock proteins (Hsps), Hsp70 and Hsp90, was elevated in response to heat stress, cold stress and during dehydration and rehydration. The response of Hsp90 was more pronounced than that of Hsp70 during dehydration and rehydration. Our results define the tolerance limits for bed bugs to these commonly encountered stresses of temperature and low humidity and indicate a role for Hsps in responding to these stresses. PMID:19941608

Benoit, J B; Lopez-Martinez, G; Teets, N M; Phillips, S A; Denlinger, D L

2009-12-01

14

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

2013-07-18

15

Short term hardening effects on survival of acute and chronic cold exposure by Drosophila melanogaster larvae  

PubMed Central

We quantified the variation and plasticity in cold tolerance among four larval stages of four laboratory strains of Drosophila melanogaster in response to both acute (<2 hours of cold exposure) and chronic (?7 hours of cold exposure) cold exposure. We observed significant differences in basal cold tolerance between the strains and among larval stages. Early larval instars were generally more tolerant of acute cold exposures than 3rd instar larvae. However, wandering larvae were more tolerant of chronic cold exposures than the other stages. Early stages also displayed a more pronounced rapid cold-hardening response than the later stages. Heat pre-treatment did not confer a significant increase in cold tolerance to any of the strains at any stage, pointing to different mechanisms being involved in resolving heat- and cold-elicited damage. However, when heat pre-treatment was combined with rapid cold-hardening as sequential pre-treatments, both positive (heat first) and negative (heat second) effects on cold tolerance were observed. We discuss possible mechanisms underlying cold-hardening and the effects of acute and chronic cold exposures.

Rajamohan, Arun; Sinclair, Brent J.

2008-01-01

16

Ettringite formation and microstructure of rapid hardening cement  

Microsoft Academic Search

This paper reports the formation and microstructure development of ettringite during hydration of two rapid hardening cements under various handling times. The rapid hardening component of one of these cements is crystalline calcium fluoroaluminate while that of the other is an amorphous calcium aluminate. During hydration, the crystalline fluoroaluminate component forms ettringite from the very beginning. The amount of ettringite

Etsuo Sakai; Yasuyuki Nikaido; Takumi Itoh; Masaki Daimon

2004-01-01

17

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

18

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

19

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

20

Malate metabolism and reactions of oxidoreduction in cold-hardened winter rye (Secale cereale L.) leaves  

Microsoft Academic Search

In cold-hardened leaves (CHL) of winter rye (Secale cereale L.) much higher levels of malate were detected by 13C-NMR than in non-hardened leaves (NHL). As this was not observed previously, malate metabolism of CHL was studied in more detail by bio- chemical assays. The activities of several enzymes of malate metabolism, NADP-malate dehydrogenase, NAD-malate dehydrogenase, phosphoenolpyruvate carboxylase, and NADP-malic enzyme,

Frauke Crecelius; Peter Streb; Jurgen Feierabend

2003-01-01

21

Strain Hardening Behavior and Cold Reducibility of Boron-added Low-carbon Steel  

NASA Astrophysics Data System (ADS)

Addition of boron in low carbon (0.06% max) hot rolled steel has improved its formability. A unique combination of properties with low strain hardening exponent ( n) and high total elongation has resulted into higher percentage of cold reducibility of hot rolled coils.

Deva, Anjana; de, Saikat K.; Jha, B. K.

2009-02-01

22

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

23

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.

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

2000-01-01

24

Characterizing Hardening on Annealing of Cold-Rolled Aluminum AA3103 Strips  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

25

Uptake and Growth-promoting Activity of Indoleacetic Acid in Segments of Cold-hardened Wheat Coleoptiles 1  

PubMed Central

Seedings of winter wheat (Triticum aestivum L. cv. Kharkov MC 22) were grown at 24 C (unhardened) and 4 C (hardened). Indoleacetic acid (IAA) was added to excised coleoptile segments after lengthy incubation and their responses were determined by photometric auxanometry at both 25 C and 5 C. The segments' rates of uptake of 14CIAA were also compared at both temperatures. Cold hardening had no significant effect on the rates of elongation and uptake in a saturating concentration of IAA (2 to 10 ?M) at either temperature. Elongation was more sensitive to temperature of measurement than was uptake. At suboptimal concentrations of IAA and 25 C, hardened coleoptiles took up [2-14C]-IAA twice as fast but elongated half as fast as unhardened coleoptiles. This and the lack of effect of cold hardening on apparent uptake of [1-14C]-IAA raised the possibility that a higher rate of IAA-decarboxylation was coupled with the higher rate of uptake of IAA by hardened coleoptiles. Homeostatic hormonal regulation was also evident in the same endogenous rates of elongation of segments of cold-hardened and unhardened coleoptiles.

Sirois, J.-Claude; Macdowall, Fergus D. H.

1977-01-01

26

Effect of prior cold work on age hardening of Cu-3Ti-1Cr alloy  

SciTech Connect

The influence of 50%, 75% and 90% cold work on the age hardening behavior of Cu-3Ti-1Cr alloy has been investigated by hardness and tensile tests, and light optical and transmission electron microscopy. Hardness increased from 118 Hv in the solution-treated condition to 373 Hv after 90% cold work and peak aging. Cold deformation reduced the peak aging time and temperature of the alloy. The yield strength and ultimate tensile strength reached a maximum of 1090 and 1110 MPa, respectively, following 90% deformation and peak aging. The microstructure of the deformed alloy exhibited elongated grains and deformation twins. The maximum strength on peak aging was obtained due to precipitation of the ordered, metastable and coherent {beta}'-Cu{sub 4}Ti phase, in addition to high dislocation density and deformation twins. Over-aging resulted in decreases in hardness and strength due to the formation of incoherent and equilibrium {beta}-Cu{sub 3}Ti phase in the form of a cellular structure. However, the morphology of the discontinuous precipitation changed to a globular form on high deformation. The mechanical properties of Cu-3Ti-1Cr alloy are superior to those of Cu-2.7Ti, Cu-3Ti-1Cd and the commercial Cu-0.5Be-2.5Co alloys in the cold-worked and peak-aged condition.

Markandeya, R. [Department of Metallurgical Engineering, College of Engineering, Jawaharlal Nehru Technological University, Kukatpally, Hyderabad-500 072 (India); Nagarjuna, S. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500 058 (India)]. E-mail: snagarjuna1@rediffmail.com; Sarma, D.S. [Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221 005 (India)

2006-12-15

27

Rapid Construction for Hardening Above-Ground Facilities to Small Arms Fire.  

National Technical Information Service (NTIS)

The purpose of this research was to develop an efficient structural system for the rapid construction of above-ground hardened shelters in the theater of operations. This system would have a short construction time, use unskilled labor, and be capable of ...

P. X. Bellini G. R. Williamson D. C. Morse

1978-01-01

28

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

29

EFFECT OF COLD HARDENING ON SOME PHOTOSYNTHETIC CHARACTERISTICS OF PEA (Pisum sativum L., CV. RAN 1) PLANTS  

Microsoft Academic Search

Summary. The effect of 96 h cold acclimation of pea (Pisum sativum L., cv. Ran 1) plants on their photosynthetic capacity was investigated. It was found that pea plants were able to modulate their photosynthetic rate dur- ing growth at low temperature and adjust it to needs for survival. The ad- vantages of hardening to low temperature were very clearly

Ivan Yordanov; Katya Georgieva; Tsonko Tsonev; Violeta Velikova

30

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

Microsoft Academic Search

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

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

2010-01-01

31

Characterization of prior cold worked and age hardened Cu-3Ti-1Cd alloy  

SciTech Connect

The influence of cold deformation by 50%, 75% and 90% on the age-hardening behavior of a Cu-3Ti-1Cd alloy has been investigated by hardness, tensile tests and light optical as well as transmission electron microscopy. The hardness of Cu-3Ti-1Cd alloy increased from 111 Hv in the solution-treated condition to 355 Hv in 90% cold worked and peak aged condition. The yield and ultimate tensile strengths of Cu-3Ti-1Cd alloy reached maxima of 922 MPa and 1035 MPa, respectively, on 90% deformation and peak aging. The microstructure of the deformed alloy exhibited elongated grains and deformation bands. The maximum strength on peak aging was brought about by the precipitation of ordered, metastable, coherent {beta}' Cu{sub 4}Ti phase, in addition to high dislocation density and deformation twins. Both the hardness and the strength of the alloy decreased on overaging due to the development of the incoherent equilibrium phase {beta} Cu{sub 3}Ti in a cellular structure form. However, the morphology of the discontinuous precipitation was changed to globular form at high deformation levels.

Markandeya, R. [Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221 005 (India)]. E-mail: marksravvala@yahoo.co.in; Nagarjuna, S. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500 058 (India); Sarma, D.S. [Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221 005 (India)

2005-05-15

32

Rapid evolution of cold tolerance in stickleback  

PubMed Central

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

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

2011-01-01

33

Cold Extrusion of Six Low-Alloy Case-Hardening Steels.  

National Technical Information Service (NTIS)

Extrusion pressure data are presented for both the forward extrusion of rod and the backward extrusion of can in six low-alloy, case-hardening steels, En 351, En 352, En 353, En 354, En 355 and En 361. The extrusion of these steels requires pressures 20-6...

J. C. Hendry

1977-01-01

34

Survivability of the Hardened Mobile Launcher When Attacked by a Hypothetical Rapidly Retargetable ICBM System.  

National Technical Information Service (NTIS)

This thesis evaluates the survivability of the hardened mobile launcher system (HML) against a hypothetical enemy ICBM system. The hypothetical system has two key capabilities: it can obtain near real-time intelligence information regarding the HML's loca...

D. J. Gearhart S. F. Merrow

1986-01-01

35

Autumn growth and cold hardening of winter wheat under simulated climate change  

Microsoft Academic Search

Plant responses to elevated CO2 are governed by temperature, and at low temperatures the beneficial effects of CO2 may be lost. To document the responses of winter cereals grown under cold conditions at northern latitudes, autumn growth of winter wheat exposed to ambient and elevated levels of temperature (+2.5°C), CO2 (+150 µmol mol), and shade (?30%) was studied in open-top

Hans M. Hanslin; Leiv M. Mortensen

2010-01-01

36

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

PubMed Central

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

Hlavackova, Iva; Vitamvas, Pavel; Santrucek, Jiri; Kosova, Klara; Zelenkova, Sylva; Prasil, Ilja Tom; Ovesna, Jaroslava; Hynek, Radovan; Kodicek, Milan

2013-01-01

37

Control of cold-hardening in the freeze-tolerant gall-fly larva, Eurosta solidaginis (Fitch) (tephrididae)  

SciTech Connect

Quantitative differences exist in cryoprotectant accumulation patterns and ice nucleating activity between latitudinally distinct populations of the gall fly Eurosta solidaginis. The objectives of this study were the determination of the following: (1) what are the quantitative effects of temperature on polyol synthesis in E. solidaginis larvae. (2) What quantitative differences exist in response to warm acclimation and reacclimation to cold between northern and southern populations of E. solidaginis larvae in polyol production. (3) What changes occur in carbon flow during low temperature acclimation in E. solidaginis larvae. (4) What is the role of gall plant water content in glycerol production in E. solidaginis larvae. (5) Where is the site of nucleation in E. solidaginis larvae. (6) What role does contact and surface moisture have in nucleation of E. solidaginis larvae. (7) Does the endocrine system play a role in the control of cold-hardening (ice nucleating agents) in E. solidaginis. Acute exposure to low temperature of local populations showed that sorbital synthesis was initiated at temperatures below +10/sup 0/C. The optimum for synthesis was around 0/sup 0/C. Glycerol levels increased linearly during the experimental period independent of temperature. Analysis of respirometric data of larvae injected with specifically labelled /sup 14/C-glucose (C/sub 1/, C/sub 3,4/ or C/sub 6/) indicated that changes in carbon flow distribution led to polyol synthesis at low temperatures. In light of the temperature independent accumulation of glycerol an attempt was made to determine the environmental trigger of its synthesis. Field data revealed a strong correlation between the water content of the plant gall and glycerol accumulation by the larvae.

Rojas, R.R.

1986-01-01

38

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

PubMed

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

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

2013-04-12

39

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

40

No snowplough mechanism during the rapid hardening of supermassive black hole binaries  

NASA Astrophysics Data System (ADS)

We present 2D hydrodynamical simulations of the tidal interaction between a supermassive black hole binary with moderate mass ratio and the fossil gas disc where it is embedded. Our study extends previous 1D height-integrated disc models, which predicted that the density of the gas disc between the primary and the secondary black holes should rise significantly during the ultimate stages of the binary's hardening driven by the gravitational radiation torque. This snowplough mechanism, as we call it, would lead to an increase in the bolometric luminosity of the system prior to the binary merger, which could be detected in conjunction with the gravitational wave signal. We argue here that the snowplough mechanism is unlikely to occur. In 2D, when the binary's hardening time-scale driven by gravitational radiation becomes shorter than the disc's viscous drift time-scale, fluid elements in the inner disc get funnelled to the outer disc through horseshoe trajectories with respect to the secondary. Mass leakage across the secondary's gap is thus found to be effective and, as a result, the predicted accretion disc luminosity will remain at roughly the same level prior to merger.

Baruteau, Clément; Ramirez-Ruiz, Enrico; Masset, Frédéric

2012-06-01

41

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.

Stoks, Robby; De Block, Marjan

2011-01-01

42

Processes Determining the Rapid Reestablishment of the Equatorial Pacific Cold Tongue\\/ITCZ Complex  

Microsoft Academic Search

The annual reestablishment of the equatorial cold tongue (ECT) in the Pacific is signified by a remarkably rapid reversal of the warming trend from March to May. The processes responsible for this dramatic turnabout are investigated using the outputs generated by a coupled ocean-atmosphere model, which simulates realistic tropical Pacific climate. A new diagnostic equation is put forward for a

Bin Wang; Xiouhua Fu

2001-01-01

43

Temperature dependence of strain hardening and plastic instability behaviors in austenitic stainless steels  

SciTech Connect

The temperature dependencies of true strain-hardening and plastic-instability properties are investigated for austenitic stainless steels; including annealed 304, 316, 316LN, and 20% cold-worked 316LN, at test temperatures from -150 to 450 deg.C. In both annealed and cold-worked conditions, strength decreases with increasing temperature, while ductility peaks below room temperature and is least at about 400 deg.C. At room temperature or below, the strain-hardening behavior exhibits two stages consisting of a rapid decrease for small strains and an increase-decrease cycle before plastic instability occurs. At higher temperatures the strain-hardening rate decreases monotonically with strain. The characteristics of these strain-hardening behaviors are explained by changes in deformation microstructure. Transmission electron microscopy (TEM) of the deformed 316LN steel shows that twins, stacking faults, and/or martensite laths, along with dislocations, are formed at subzero temperatures, and dislocation-dominant microstructures at elevated temperatures. It is also shown that the average strain-hardening rate during necking to failure is almost equal to the true stress at the onset of necking. This stress is called the plastic instability stress (PIS). Cold-worked specimens fail by prompt necking at yield when the yield stress exceeds the PIS of annealed material, indicating that the PIS is independent of prior cold work.

Byun, T.S.; Hashimoto, N.; Farrell, K

2004-08-02

44

Survivability of the hardened mobile launcher when attacked by a hypothetical rapidly retargetable ICBM system. Master's thesis  

SciTech Connect

This thesis evaluates the survivability of the hardened mobile launcher system (HML) against a hypothetical enemy ICBM system. The hypothetical system has two key capabilities: it can obtain near real-time intelligence information regarding the HML's location, and it can be retargeted in flight (as necessary) according to the intelligence information. Thus, the hypothetical ICBM threat systems can attack individual HMLs directly rather than rely on a barrage attack against HML bases. Monte Carlo simulation is used to approach the problem. The model is an MBASIC computer program, written and runs on an Apple Macintosh computer. The model simulates the flight of the attacking ICBMs (there may be as few as one or as many as 14 warheads directed at each HML) and the random dispersal tactics of a single HML. The model determines the locations of the detonations and the location of the HML at time of detonation. Based on these locations, probability of kill due to peak-blast overpressure is calculated. A key parameter in the model is intelligence / retargeting cycle time -- the time required to obtain intelligence and retarget accordingly. This time is varied from 1-30 minutes. The model also allows variations in HML speed and hardness and threat system CEP. A subroutine for examining the effects of neutron fratricide on the attacking warheads is included (although the effects were found to be negligible). The thesis concludes that very small intelligence/retargeting cycle times are required for this to be an effective weapon system against the HML. Thus, with today's (or near future) technology, the HML can be considered a very survivable system.

Gearhart, D.J.; Merrow, S.F.

1986-03-01

45

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

46

The significance of a rapid cold hemagglutination test for detecting mycoplasma infections in children with asthma exacerbation  

Microsoft Academic Search

Background and Purpose: Mycoplasma pneumoniae infection is a frequent cause of community-acquired respiratory infections in children and adults. However, standardized, rapid, specific methods for its diagnosis are lacking. The relationship between M. pneumoniae infection and asthma exacerbation has been recently discussed in the literature. We investigated the accuracy of rapid detection of mycoplasma infection by cold hemagglutination test compared to

Ya-Ting Chang; Yao-Hsu Yang; Bor-Luen Chiang

47

Acute Myocardial Infarction Induced by Alternating Exposure to Heat in a Sauna and Rapid Cooling in Cold Water  

Microsoft Academic Search

We describe a patient with acute myocardial infarction, which was thought to result from plaque rupture or thrombosis because of coronary artery spasm. The vasospasm was most likely induced by stimulation of the ?-adrenergic receptors during alternating heat exposure during sauna bathing and rapid cooling during cold water bathing. This report emphasizes the dangers of rapid cooling after sauna bathing

Yukiko Imai; Sachihiko Nobuoka; Junzo Nagashima; Toru Awaya; Jiro Aono; Fumihiko Miyake; Masahiro Murayma

1998-01-01

48

Structure and mechanical properties of low-carbon structural steels hardened in mill flux  

Microsoft Academic Search

1.A structure providing for a yield point of no less than sy = 350 N\\/mm2 in combionation with sufficiently high cold resistance is formed when a rolled product of low-carbon steel St3 is hardened in mill flux.2.The use of rapid surface cooling (600–800°\\/sec) is most effective for the acquisition of appreciably higher strength (sy = 400–600 N\\/mm2); as a result,

P. D. Odesskii; D. P. Khromov

1992-01-01

49

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

50

Cold tolerance and cold-induced modulation of gene expression in two Drosophila virilis group species with different distributions.  

PubMed

The importance of high and low temperature tolerance in adaptation to changing environmental conditions has evoked new interest in modulations in gene expression and metabolism linked with stress tolerance. We investigated the effects of rapid cold hardening and cold acclimatization on the chill coma recovery times of two Drosophila virilis group species, Drosophila montana and D. virilis, with different distributions and utilized a candidate gene approach to trace changes in their gene expression during and after the cold treatments. The study showed that cold acclimatization clearly decreases chill coma recovery times in both species, whereas rapid cold hardening did not have a significant effect. Microarray analysis revealed several genes showing expression changes during different stages of cold response. Amongst the 219 genes studied, two genes showed rather consistent expression changes: hsr-omega, which was up-regulated in both study species during cold acclimatization, and Eip71CD, which was down-regulated in nearly all of the cold treatments. In addition, 29 genes showed expression changes that were more treatment- and/or species specific. Overall, different stages of cold response elicited changes mainly in genes involved in heat shock response, circadian rhythm and metabolism. PMID:22122733

Vesala, Laura; Salminen, T S; Laiho, A; Hoikkala, A; Kankare, M

2011-11-28

51

Detecting freeze injury and seasonal cold-hardening of cells and tissues in the gall fly larvae, Eurosta solidaginis (Diptera: Tephritidae) using fluorescent vital dyes.  

PubMed

This study identified a hierarchy in levels of cold tolerance for diverse tissues from larvae of Eurosta solidaginis. Following freezing at -80 degrees C, larval survival and the viability of specific tissues were assessed using membrane-permeant DNA stain (SYBY-14) and propidium iodide. Integumentary muscle, hemocytes, tracheae, and the crystal-containing portion of the Malpighian tubules were most susceptible to freezing injury. A second group consisting of fat body, salivary glands, and the proximal region of the Malpighian tubules were intermediate in their susceptibility, while the foregut, midgut, and hindgut were the most resistant to freezing injury. Seasonal increases in larval cold tolerance were closely matched by changes in the cold tolerance of individual tissues. Compared to larvae collected in September, the survival rates for each of the six tissues tested from October-collected larvae increased by 20-30%. The survival rate in all tissues was notably higher than that of whole animals, indicating that larval death could not be explained by the mortality in any of the tissues we tested. This method will be useful for assessing the nature of chilling/freezing injury, the role cryoprotectants, and cellular changes promoting cold tolerance. PMID:14568577

Yi, Shu-Xia; Lee, Richard E

2003-11-01

52

Hairpin Folding Dynamics:  The Cold-Denatured State Is Predisposed for Rapid Refolding †  

Microsoft Academic Search

Cold denaturation is a general phenomenon in globular proteins, and the associated cold- denatured states of proteins have important fundamental and practical significance. Here, we have characterized the cold-denatured state of a ‚-hairpin forming peptide, MrH3a, in 8% hexafluoro-2-propanol (HFIP) and the dynamics of its refolding following a laser-induced T-jump. ‚-Hairpins constitute an important class of protein structural elements, yet

R. Brian Dyer; Shelia J. Maness; Stefan Franzen; R. Matthew Fesinmeyer; Katherine A. Olsen; Niels H. Andersen

2005-01-01

53

Detecting freeze injury and seasonal cold-hardening of cells and tissues in the gall fly larvae, Eurosta solidaginis (Diptera: Tephritidae) using fluorescent vital dyes  

Microsoft Academic Search

This study identified a hierarchy in levels of cold tolerance for diverse tissues from larvae of Eurosta solidaginis. Following freezing at ?80 °C, larval survival and the viability of specific tissues were assessed using membrane-permeant DNA stain (SYBY-14) and propidium iodide.Integumentary muscle, hemocytes, tracheae, and the crystal-containing portion of the Malpighian tubules were most susceptible to freezing injury. A second

Shu-Xia Yi; Richard E Lee

2003-01-01

54

Rapid short-duration hypothermia with cold saline and endovascular cooling before reperfusion reduces microvascular obstruction and myocardial infarct size  

PubMed Central

Background The aim of this study was to evaluate the combination of a rapid intravenous infusion of cold saline and endovascular hypothermia in a closed chest pig infarct model. Methods Pigs were randomized to pre-reperfusion hypothermia (n = 7), post-reperfusion hypothermia (n = 7) or normothermia (n = 5). A percutaneous coronary intervention balloon was inflated in the left anterior descending artery for 40 min. Hypothermia was started after 25 min of ischemia or immediately after reperfusion by infusion of 1000 ml of 4°C saline and endovascular hypothermia. Area at risk was evaluated by in vivo SPECT. Infarct size was evaluated by ex vivo MRI. Results Pre-reperfusion hypothermia reduced infarct size/area at risk by 43% (46 ± 8%) compared to post-reperfusion hypothermia (80 ± 6%, p < 0.05) and by 39% compared to normothermia (75 ± 5%, p < 0.05). Pre-reperfusion hypothermia infarctions were patchier in appearance with scattered islands of viable myocardium. Pre-reperfusion hypothermia abolished (0%, p < 0.001), and post-reperfusion hypothermia significantly reduced microvascular obstruction (10.3 ± 5%; p < 0.05), compared to normothermia: (30.2 ± 5%). Conclusion Rapid hypothermia with cold saline and endovascular cooling before reperfusion reduces myocardial infarct size and microvascular obstruction. A novel finding is that hypothermia at the onset of reperfusion reduces microvascular obstruction without reducing myocardial infarct size. Intravenous administration of cold saline combined with endovascular hypothermia provides a method for a rapid induction of hypothermia suggesting a potential clinical application.

Gotberg, Matthias; Olivecrona, Goran K; Engblom, Henrik; Ugander, Martin; van der Pals, Jesper; Heiberg, Einar; Arheden, Hakan; Erlinge, David

2008-01-01

55

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

Microsoft Academic Search

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

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

2011-01-01

56

[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

57

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

Microsoft Academic Search

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

A. Johnston; D. Senkovich

2007-01-01

58

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

PubMed

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

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

2013-07-31

59

Calcium signaling mediates cold sensing in insect tissues.  

PubMed

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

2013-05-13

60

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

SciTech Connect

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

Chiu M.; PHENIX Collaboration

2011-11-10

61

Increased abundance of Frost mRNA during recovery from cold stress is not essential for cold tolerance in adult Drosophila melanogaster.  

PubMed

Frost (Fst) is a candidate gene associated with the response to cold in Drosophila melanogaster because Fst mRNA accumulation increases during recovery from low temperature exposure. We investigated the contribution of Fst expression to chill-coma recovery time, acute cold tolerance and rapid cold hardening (RCH) in adult D.?melanogaster by knocking down Fst?mRNA expression using GAL4/UAS-mediated RNA interference. In this experiment, four UAS-Fst and one tubulin-GAL4 lines were used. We predicted that if Fst is essential for cold tolerance phenotypes, flies with low Fst?mRNA levels should be less cold tolerant than flies with normal levels of cold-induced Fst?mRNA. Cold-induced Fst abundance and recovery time from chill-coma were not negatively correlated in male or female flies. Survival of 2?h exposures to sub-zero temperatures in Fst knockdown lines was not lower than that in a control line. Moreover, a low temperature pretreatment increased survival of severe cold exposure in flies regardless of Fst abundance level during recovery from cold stress, suggesting that Fst expression is not essential for RCH. Thus, cold-induced Fst accumulation is not essential for cold tolerance measured as chill-coma recovery time, survival to acute cold stress and RCH response in adult D.?melanogaster. PMID:23901849

Udaka, H; Percival-Smith, A; Sinclair, B J

2013-07-31

62

Rapid multiplex PCR assay to identify respiratory viral pathogens: moving forward diagnosing the common cold.  

PubMed

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

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

2013-09-01

63

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

PubMed Central

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

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

2013-01-01

64

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

65

42. INTERIOR VIEW OF THE NAIL HARDENER USED TO HARDEN ...  

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

42. INTERIOR VIEW OF THE NAIL HARDENER USED TO HARDEN AND TEMPER THE NAILS; WEST TUBES IN FOREGRPUND AND DRAWBACK TUBE IN THE CENTER - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

66

The surface layer of surface-hardened parts of heat-resisting alloys  

Microsoft Academic Search

The effect of surface hardening by cold working depends mainly on the stability of residual compressive stresses. The residual stresses decrease greatly in the first hours at elevated temperature and then change slowly. The time that the effect of surface hardening is retained in heat-resisting alloys can be determined approximately — from the decoration of the structure with dislocations —

Yu. V. Poloshkin; V. V. Davykova

1971-01-01

67

Hardened Subtidal Stromatolites, Bahamas  

Microsoft Academic Search

Hardened, high-relief stromatolites have been discovered along the margins of some Bahamian platforms. They occur in high-energy (tidal) oolitic sand environments in waters ranging in depth from about 1 to 5 meters. Physical stress produced by actively migrating bed forms of oolitic sand appears to exclude grazing gastropods and subsequent community successions, permitting stromatolite growth.

Jeffrey J. Dravis

1983-01-01

68

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

69

Rapid Repair of CB Hardened Systems.  

National Technical Information Service (NTIS)

POLYMERight has developed and tested an adhesive system for field repair kits for collective protection shelters. This system can eliminate vulnerability of personnel created when CB protective shelters are breached. The adhesive chemistry utilized can qu...

L. Rappoport

2004-01-01

70

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

71

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

72

Cold injuries.  

PubMed

There are two categories of cold injury. The first is hypothermia, which is a systemic injury to cold, and the second is frostbite, which is a local injury. Throughout history, entire armies, from George Washington to the Germans on the Russian Front in World War II, have fallen prey to prolonged cold exposure. Cold injury is common and can occur in all seasons if ambient temperature is lower than the core body temperature. In the 1985 Boston Marathon, even though it was 76 degrees and sunny, there were 75 runners treated for hypothermia. In general, humans adapt poorly to cold exposure. Children are at particular risk because of their relatively greater surface area/body mass ratio, causing them to cool even more rapidly than adults. Because of this, the human's best defense against cold injury is to limit his/her exposure to cold and to dress appropriately. If cold injury has occurred and is mild, often simple passive rewarming such as dry blankets and a warm room are sufficient treatment. PMID:17630517

Kruse, R J

1995-01-01

73

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...

74

Precipitation hardening of aluminum alloys  

Microsoft Academic Search

The author's charge was to discuss recent trends in research and development on precipitation hardened aluminum alloys and to indicate where research is needed. This will be done for three areas: fatigue, properties of grain boundaries and interfaces, and stability of precipitates at elevated temperatures. Present strong precipitation hardened aluminum alloys do not have high endurance limits. One problem is

Morris E. Fine

1975-01-01

75

Solute Enhanced Strain Hardening of Aluminum Alloys to Achieve Improved Combinations of Strength and Toughness  

NASA Astrophysics Data System (ADS)

The feasibility of achieving improved combinations of strength and toughness in aluminum alloy 2524 through solute enhanced strain hardening (SESH) has been explored in this study and shown to be viable. The effectiveness of SESH is directly dependent on the strain hardening rate (SHR) of the material being processed. Aluminum alloy 2524 naturally ages to the T4-temper after solution heat treating and quenching. The SHR of strain free and post cold rolled material as a function of natural aging time has been measured by means of simple compression. It has been determined that the SHR of AA2524 is more effective with solute in solution rather than clustered into GP zones. It has also been shown that the typical rapid formation of GP zones at room temperature (natural aging) is inhibited by moderate cold rolling strains (?CR ? 0.2) through dislocation aided vacancy annihilation. The practical limitations of quenching rate have been determined using hardness and eddy current electrical conductivity measurements. It has been shown that too slow of a quench rate results in solute being lost to both the formation of GP zones and embrittling precipitates during the quench, while too rapid of a quench rate results in mid-plane cracking of the work piece during the SESH processing. The mid-plane cracking was overcome by using an uphill quenching procedure to relieve residual stresses within the work piece. Aluminum alloy 2524 strengthened through SESH to a yield strength 11% greater than that in the T6-Temper exhibits: equivalent toughness, 5% greater UTS, 1% greater elongation, 7% greater R.A., and absorbs 15% more energy during tensile testing. At yield strengths comparable to published data for 2x24 alloys, the SESH 2524 exhibited up to a 60% increase in fracture toughness. The fractured surfaces of the SESH material exhibited transgranular dimpled rupture as opposed to the grain boundary ductile fracture (GBPF) observed in the artificially aged material.

Hovanec, Christopher James

76

The effect of aging and cold working on the high-temperature low-cycle fatigue behavior of alloy 800H: Part I. The effect of hardening processes on the initial stress-strain curve  

Microsoft Academic Search

The individual and combined effects of cold working (5 and 10 pct) and aging (4000 and 8000 h at 538 to 760?) on the microstructure\\u000a and high-temperature yield strength of al-loy 800H have been investigated. The specimens were tested at the aging temperatures.\\u000a During testing some of the specimens showed the phenomenon of serrated yielding. In order of importance, the

R. E. Villagrana; J. L. Kaae; J. R. Ellis; P. K. Gantzel

1978-01-01

77

The effect of aging and cold working on the high-temperature low-cycle fatigue behavior of alloy 800H: Part I. The effect of hardening processes on the initial stress-strain curve  

Microsoft Academic Search

The individual and combined effects of cold working (5 and 10 pct) and aging (4000 and 8000 h at 538 to 760°) on the microstructure and high-temperature yield strength of al-loy 800H have been investigated. The specimens were tested at the aging temperatures. During testing some of the specimens showed the phenomenon of serrated yielding. In order of importance, the

R. E. Villagrana; J. L. Kaae; J. R. Ellis; P. K. Gantzel

1978-01-01

78

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

79

Abnormal strain hardening in nanostructured titanium at high strain rates and large strains  

Microsoft Academic Search

Commercial purity nanostructured titanium prepared by equal channel angular pressing plus cold rolling (grain size ?260 nm)\\u000a exhibits a nonnegligible strain hardening behavior at large compressive strains (>15%) and quasistatic loading conditions.\\u000a The degree of the strain hardening increases with increasing strain rates and becomes more pronounced at dynamic loading rates.\\u000a This behavior is in contrast with what we have seen

Y. M. Wang; J. Y. Huang; T. Jiao; Y. T. Zhu; A. V. Hamza

2007-01-01

80

Fire vehicle hardening  

SciTech Connect

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

Horner, L.G.

1988-11-01

81

Precipitation hardening of aluminum alloys  

Microsoft Academic Search

The author’s charge was to discuss recent trends in research and development on precipitation hardened aluminum alloys and\\u000a to indicate where research is needed. This will be done for three areas: fatigue, properties of grain boundaries and interfaces,\\u000a and stability of precipitates at elevated temperatures. Present strong precipitation hardened aluminum alloys do not have\\u000a high endurance limits. One problem is

Morris E. Fine

1975-01-01

82

Resist hardening without surface deviation  

Microsoft Academic Search

We report on a novel technique for hardening micro-optical resist elements, like beam-shaping elements or micro lenses, with large profile depths before proportional transfer into the fused silica substrate. This technique allows to harden the resist with only small distorsions of the height profile. For demonstration a refractive beam shaper was designed and fabricated in photo-resist using gray-tone lithography. This

Holger Hartung; Matthias Cumme; Mike Thieme; Ernst-Bernhard Kley; Andreas Tünnermann

2003-01-01

83

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

Konicek-Moran, Richard

2008-04-01

84

Deformation of plastically compressible hardening-softening-hardening solids  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

85

Combined transcriptomic and metabolomic approach uncovers molecular mechanisms of cold tolerance in a temperate flesh fly.  

PubMed

The ability to respond rapidly to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to nonlethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a combination of transcriptomics and metabolomics to examine the molecular mechanisms of RCH and cold shock recovery in the flesh fly, Sarcophaga bullata. Surprisingly, out of ?15,000 expressed sequence tags (ESTs) measured, no transcripts were upregulated during RCH, and likewise RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ?1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. In the metabolome, RCH had a slight yet significant effect on several metabolic pathways, while cold shock resulted in dramatic increases in gluconeogenesis, amino acid synthesis, and cryoprotective polyol synthesis. Several biochemical pathways showed congruence at both the transcript and metabolite levels, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock. Thus, while RCH had very minor effects on gene expression, recovery from cold shock elicits sweeping changes in gene expression and metabolism along numerous cell signaling and biochemical pathways. PMID:22735925

Teets, Nicholas M; Peyton, Justin T; Ragland, Gregory J; Colinet, Herve; Renault, David; Hahn, Daniel A; Denlinger, David L

2012-06-26

86

Rapid method for the determination of total mercury in urine samples using cold vapour atomic fluorescence spectrometry.  

PubMed

A rapid method for the determination of total mercury in urine samples is proposed. Samples are digested using a bromination procedure at room temperature. Analysis is performed using automated continuous flow vapour generation coupled to atomic fluorescence spectrometry. This approach allowed the analysis of 30 samples per hour and a limit of detection of 1 ng l-1. The analytical procedure was assessed using certified reference material NBS 2672a freeze-dried urine and two batches of Seronorm trace elements in urine samples. PMID:7872489

Corns, W T; Stockwell, P B; Jameel, M

1994-11-01

87

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

ERIC Educational Resources Information Center

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

Ead, J.; Devonald, V. G.

1975-01-01

88

Energetic model of metal hardening  

NASA Astrophysics Data System (ADS)

Based on Bailey hypothesis on the link between strain hardening and elastic lattice defect energy this paper suggests a shear strength energetic model that takes into consideration plastic strain intensity and rate as well as softening related to temperature annealing and dislocation annihilation. Metal strain hardening was demonstrated to be determined only by elastic strain energy related to the energy of accumulated defects. It is anticipated that accumulation of the elastic energy of defects is governed by plastic work. The suggested model has a reasonable agreement with the available experimental data for copper up to P = 70 GPa , for aluminum up to P = 10 GPa and for tantalum up to P = 20 GPa.

Ignatova, O. N.; Raevsky, V. A.

89

Onycholysis induced by nail hardener.  

PubMed

Nail hardeners appeared in the market during the 1960s. They were basically solutions of formaldehyde. The first adverse effects were published in 1966 (1). Reactions were onycholysis, chromonychia, subungual haemorrhage, and hyperkeratosis. Onycholysis may be non-inflammatory or inflammatory, and is accompanied by throbbing pain. Inflammatory reactions are followed by paronychia and occasional dermatitis on the digital pulpa. PMID:17868227

Helsing, Per; Austad, Joar; Talberg, Hans Jørgen

2007-10-01

90

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

91

Selective Hardening in Early Design Steps  

Microsoft Academic Search

Hardening a circuit against soft errors should be performed in early design steps before the circuit is laid out. A viable approach to achieve soft error rate (SER) reduction at a reasonable cost is to harden only parts of a circuit. When selecting which locations in the circuit to harden, priority should be given to critical spots for which an

Christian G. Zoellin; Hans-Joachim Wunderlich; Ilia Polian; Bernd Becker

2008-01-01

92

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

93

Effect of the original structure on softening of cold-worked steel during heating  

Microsoft Academic Search

1.The carbon content affects softening during subsequent heating of cold-worked steels. With increasing carbon concentrations the hardening effect is retained after heating to higher temperatures.2.During subsequent annealing, cold-worked steels retain the hardening effect up to ~ 10% deformation, which is due to polygonization and formation of a cellular structure.3.Softening of cold-worked steels depends on the original structure of the pearlite.

V. E. Pil'guk; M. S. Podgaiskii; V. I. Ikonnikov; R. P. Malova; V. A. Kharchenko

1979-01-01

94

Textural and microstructural changes associated with post-harvest hardening of trifoliate yam ( Dioscorea dumetorum) pax tubers  

Microsoft Academic Search

The textural and microstructural changes associated with the post-harvest hardening phenomenon of Dioscorea dumetorum tubers were studied to determine how texture relates to microstructure during the hardening process. A 2×2×4 factorial experiment with sample treatment, storage conditions and storage time as variables was performed. The tubers were harvested, matured and stored under prevailing tropical ambient conditions (28 °C) and cold room

Emmanuel Ohene Afoakwa; Samuel Sefa-Dedeh

2002-01-01

95

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.

Rajashekar, C. B.; Lafta, A.

1996-01-01

96

Cold Hardening of Meloidogyne hapla Second-stage Juveniles.  

PubMed

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

Forge, T A; Macguidwin, A E

1990-01-01

97

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 ...

98

DISPERSION HARDENING OF URANIUM METAL  

DOEpatents

A method of hardening U metal involves the forming of a fine dispersion of UO/sub 2/. This method consists of first hydriding the U to form a finely divided powder and then exposing the powder to a very dilute O gas in an inert atmosphere under such pressure and temperature conditions as to cause a thin oxide film to coat each particle of the U hydride, The oxide skin prevents agglomeration of the particles as the remaining H is removed, thus preserving the small particle size. The oxide skin coatings remain as an oxide dispersion. The resulting product may be workhardened to improve its physical characteristics. (AEC)

Arbiter, W.

1963-01-15

99

Organics, polymers and nanotechnology for radiation hardening and shielding applications  

NASA Astrophysics Data System (ADS)

Recent studies have indicated that polymers integrated with nanoparticles and nanostructures have a high potential for increasing the space radiation resistance and hardening of photonic and electronic components. Discussed within this paper are recent data which support the premise that certain nanotechnology may improve the radiation resistance of organics, polymers, biopolymers and hybrid polymer-inorganic materials and devices to ionizing and displacement radiations. These materials are also being investigated for their ability to provide protective radiation shielding to a wide spectrum of radionuclide and galactic cosmic ray emissions such as alpha particles, protons, electrons, gamma-rays, beta rays, x-rays and neutrons. The appeal for advancing nanotechnology based materials and devices in many cases centers on the rapid development of hardened, economical and lightweight technologies that surpass the performance of current photonic, biotronic and microelectronic device and material technologies.

Taylor, Edward W.

2007-10-01

100

Cosmic-ray Helium Hardening  

NASA Astrophysics Data System (ADS)

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, 1015eV, and (2) all CR spectra become hard at gsim1011eV nucleon-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 ~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 ~106 K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito

2011-03-01

101

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

2013-02-08

102

Challenges in hardening technologies using shallow-trench isolation  

SciTech Connect

Challenges related to radiation hardening CMOS technologies with shallow-trench isolation are explored. Results show that trench hardening can be more difficult than simply replacing the trench isolation oxide with a hardened field oxide.

Shaneyfelt, M.R.; Dodd, P.E.; Draper, B.L.; Flores, R.S.

1998-02-01

103

Modelling solid solution hardening in stainless steels  

Microsoft Academic Search

The solid solution hardening of stainless steels is studied by using the Labusch–Nabarro relation. Models are evaluated in order to predict the mechanical properties from chemical composition, solution hardening misfit parameters, grain size, ferrite content and product thickness. A data source of six grades of steels is used for the modelling. Both austenitic and duplex stainless steels are covered including

Henrik Sieurin; Johan Zander; Rolf Sandström

2006-01-01

104

Cyclic hardening mechanisms in NIMONIC 80A  

Microsoft Academic Search

A nickel base superalloy was fatigued under constant plastic strain range (??p) control. The hardening response was investigated as a function of ??p and particle size of the ? ? phase. Hardening was found to be a function of the slip band spacing,i. Numerous measurements ofi and other statistical data on the slip band structures were obtained. Interactions between intersecting

B. A. Lerch; V. Gerold

1987-01-01

105

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

106

Bias-hardened CMB lensing  

NASA Astrophysics Data System (ADS)

We present new methods for lensing reconstruction from CMB temperature fluctuations which have smaller mean-field and reconstruction noise bias corrections than current lensing estimators, with minimal loss of signal to noise. These biases are usually corrected using Monte Carlo simulations, and to the extent that these simulations do not perfectly mimic the underlying sky, there are uncertainties in the bias corrections. The bias-hardened estimators which we present can have reduced sensitivity to such uncertainties, and provide a desirable cross-check on standard results. To test our approach, we also show the results of lensing reconstruction from simulated temperature maps given on 10 × 10 deg2, and confirm that our approach works well to reduce biases for a typical masked map in which 70 square masks each having 10 arcmin on a side exist, covering 2 per cent of the simulated map, which is similar to the masks used in the current SPT lensing analysis.

Namikawa, Toshiya; Hanson, Duncan; Takahashi, Ryuichi

2013-05-01

107

Effect of recrystallization-free hardening at high temperatures on the mechanical properties of dispersionally hardenable steels  

Microsoft Academic Search

1.High-temperature hardening has a favorable effect on the properties of aged austenitic steels; it increases their ultimate strength and their impact strength.2.High-temperature hardening decreases transcrystalline embrittlement resulting from dispersional hardening.3.Partial recrystallization during high-temperature hardening does not prevent the improvement of the mechanical properties of dispersionally hardened steel.4.High-temperature hardening combined with aging makes it possible to obtain very good mechanical properties

V. G. Gorbach; K. A. Malyshev; A. V. Gess; P. A. Ustyugov

1964-01-01

108

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.

2007-12-12

109

Common cold  

MedlinePLUS

... C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2007, Issue 3. Art. ... M, Das RR. Zinc for the common cold. Cochrane Database of Systematic Reviews 2011, Issue 2. Art. ...

110

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

111

Cyclic hardening mechanisms in NIMONIC 80A  

NASA Astrophysics Data System (ADS)

A nickel base superalloy was fatigued under constant plastic strain range (??p) control. The hardening response was investigated as a function of ??p and particle size of the ? ' phase. Hardening was found to be a function of the slip band spacing, i. Numerous measurements of i 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.

1987-12-01

112

Experimental study on Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the ferrite region  

Microsoft Academic Search

A Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile

Ji-ping Chen; Yong-lin Kang; Ying-min Hao; Guang-ming Liu; Ai-ming Xiong

2009-01-01

113

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.

Mansur, Louis K. (105 Timbercrest Dr., Clinton, TN 37716); Lee, Eal H. (189 Outer Dr., Oak Ridge, TN 37830)

1992-01-01

114

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

115

SEMIAUSTENITIC PRECIPITATION-HARDENABLE STAINLESS STEELS  

Microsoft Academic Search

A summary is given of the classification, metallurgy, treatment, and ; properties of the semiaustenitic precipitatson-hardenable stainless steels: 17-7 ; PH, AM 350, AM 355, PH 15-7 Mo, AM 357, and AM 359. (auth);

Ludwigson

1961-01-01

116

Study of a Method of Accelerated Hardening of Concrete by Microwaves.  

National Technical Information Service (NTIS)

The present study shows that the application of heat by means of centimetric waves produces rapid hardening of various types of concrete. The results prove that it is possible by this process to obtain within two hours a strength which may reach 50% of th...

M. Darcemont J. Bresson

1975-01-01

117

Method for Determining the Hardness of Strain Hardening Articles of Tungsten-Nickel-Iron Alloy.  

National Technical Information Service (NTIS)

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, measu...

S. A. Wallace

1981-01-01

118

Mechanism of minimum quantity lubrication in high-speed milling of hardened steel  

Microsoft Academic Search

The rapid wear rate of cutting tools due to high cutting temperature is a critical problem to be solved in high-speed machining (HSM) of hardened steels. Near-dry machining such as minimum quantity lubrication (MQL) is regarded as one of the solutions to this difficulty. However, the function of MQL in HSM is still uncertain so far which prevents MQL from

Y. S. Liao; H. M. Lin

2007-01-01

119

Laser transformation hardening of tempered 4340 steel  

Microsoft Academic Search

A CO2 laser with a fixed laser power of 1.8 KW was employed to harden the surface of some AISI 4340 steel specimens, with a scan\\u000a rate from 5 to 10 mm\\/s. The influence of scan rates and tempering treatments of the alloy on the hardness profile and microstructure\\u000a of the laserhardened zone was analyzed. Microstructures in the hardened zone

R. K. Shiue; C. Chen

1992-01-01

120

Gate sizing to radiation harden combinational logic  

Microsoft Academic Search

A gate-level radiation hardening technique for cost-effective reduction of the soft error failure rate in combinational logic circuits is described. The key idea is to exploit the asymmetric logical masking probabilities of gates, hardening gates that have the lowest logical masking probability to achieve cost-effective tradeoffs between overhead and soft error failure rate reduction. The asymmetry in the logical masking

Quming Zhou; Kartik Mohanram

2006-01-01

121

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

Microsoft Academic Search

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

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

2005-01-01

122

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

2011-06-10

123

Cold-induced photoinhibition affects establishment of Eucalyptus nitens (Deane and Maiden) Maiden and Eucalyptus globulus Labill  

Microsoft Academic Search

The effects of cold-induced photoinhibition on Eucalyptus globulus and Eucalyptus nitens seedlings were assessed between planting and age 23 weeks. The seedlings were subjected to four treatments before planting: non-hardened (NH) E. globulus and E. nitens, cold-hardened (CH) E. nitens, and nutrient-starved (NS) E. nitens. Seedlings were planted alongside established 1-year-old E. nitens saplings. The experimental site was at 350

Dugald C. Close; Chris L. Beadle; Philip H. Brown; Greg K. Holz

2000-01-01

124

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

125

Thermoelastoplastic and residual stress analysis during induction hardening of steel  

SciTech Connect

A theoretical model was developed to predict the thermoelastoplastic and residual stresses developed in a round steel bar during induction hardening. For numerical analysis, a quasi-static, uncoupled thermoelastoplastic solution based on the hyperbolic sine law of Tien and Richmond was formulated. The properties of the material were assumed to be temperature dependent. The phase transformation was considered in the numerical calculation, and the results were compared with the case where phase transformation is avoided. The cylinder was heated rapidly; once the temperature of the outer surface exceeded the transformation temperature, the cylinder was rapidly cooled. Accordingly, in the numerical calculation, only the area at the vicinity of the outer surface was assumed to transform to martensite. The results showed that the compressive residual stresses at the vicinity of the outer surface were considerably higher than the tensile stresses at the center.

Jahanian, S. [Pennsylvania State Univ., Altoona, PA (United States). Dept. of Mechanical Engineering Technology

1995-12-01

126

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

127

Characterization of the hydrogen induced cold cracking susceptibility at simulated weld zones in HSLA100 steel  

Microsoft Academic Search

The relative susceptibilities to hydrogen induced cold cracking were evaluated for HY-100, a steel presently in service in naval applications and for HSLA-100. The martensitic microstructure of the HY-100 undergoes wide variations in the heat affected zone during welding which strongly influence the resistance of that alloy to cold cracking. The HSLA-100, a low carbon, precipitation hardened steel with similar

M. R. Stoudt; R. E. Ricker

1994-01-01

128

Cold Intolerance  

MedlinePLUS

... Professionals Excerpt from the Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors © Cold Intolerance Many polio survivors report that their feet have always been cold to the touch, their skin a purplish color. As they age, their limbs become more sensitive ...

129

Laser Hardening Prediction Tool Based On a Solid State Transformations Numerical Model  

NASA Astrophysics Data System (ADS)

This paper presents a tool to predict hardening layer in selective laser hardening processes where laser beam heats the part locally while the bulk acts as a heat sink. The tool to predict accurately the temperature field in the workpiece is a numerical model that combines a three dimensional transient numerical solution for heating where is possible to introduce different laser sources. The thermal field was modeled using a kinetic model based on Johnson-Mehl-Avrami equation. Considering this equation, an experimental adjustment of transformation parameters was carried out to get the heating transformation diagrams (CHT). With the temperature field and CHT diagrams the model predicts the percentage of base material converted into austenite. These two parameters are used as first step to estimate the depth of hardened layer in the part. The model has been adjusted and validated with experimental data for DIN 1.2379, cold work tool steel typically used in mold and die making industry. This steel presents solid state diffusive transformations at relative low temperature. These transformations must be considered in order to get good accuracy of temperature field prediction during heating phase. For model validation, surface temperature measured by pyrometry, thermal field as well as the hardened layer obtained from metallographic study, were compared with the model data showing a good adjustment.

Martínez, S.; Ukar, E.; Lamikiz, A.; Liebana, F.

2011-01-01

130

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

131

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

132

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

133

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

2007-03-03

134

Modeling of Irradiation Hardening of Polycrystalline Materials  

SciTech Connect

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

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

2011-09-14

135

Recent advances in surface hardening of titanium  

NASA Astrophysics Data System (ADS)

Titanium and its alloys are used significantly in defense, aerospace and biomedical device components. However, their poor wear resistance and surface integrity leads to galling and seizure of surfaces when contact or relative motions of surfaces are involved. Surface hardening of Ti is therefore actively pursued to minimize the wear and fretting of components in these applications. The purpose of this review is to highlight some of the recent advances in surface hardening of Ti and its alloys, especially by diffusion of interstitial elements such as nitrogen, oxygen, and boron. These interstitial elements react with Ti to form hard and wear resistant compound layers at the surface and thereby, enhance the wear/abrasion properties. The recent developments pertaining to these surface hardening techniques in terms of the process parameters, microstructural details and enhancement in mechanical/wear properties are summarized in this review.

Sarma, B.; Ravi Chandran, K. S.

2011-02-01

136

The radiation hardening of communication equipment  

NASA Astrophysics Data System (ADS)

The hardening of communication equipment against ionizing and electromagnetic radiation is examined with reference to the effects of nuclear explosions, the operation of nuclear power plants, and the effects of radiation on spacecraft systems. Published studies concerning the effects of ionizing radiation on communication equipment (circuits, networks, and semiconductor components) are reviewed. Particular consideration is given to the main characteristics of the radiation environment; the design of hardened equipment; related optimization methods; and the use of mathematical modeling to evaluate radiation stability during the design stages.

Myrova, L. O.; Chepizhenko, A. Z.

137

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

138

Laser Transformation Hardening of Firing Zone Cutout Cams.  

National Technical Information Service (NTIS)

This manufacturing technology (MT) project developed techniques to use laser transformation hardening to replace cyanide salt bath nitriding to case harden firing zone cutout cams for the Mk 10 Guided Missile Launcher System (GMLS). These cams, machined o...

R. W. Lowry

1981-01-01

139

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

140

Centrality, rapidity, and transverse-momentum dependence of cold nuclear matter effects on J/psi production in dAu, CuCu, and AuAu collisions at sq root(s{sub NN})=200 GeV  

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 sq root(s{sub NN})=200 GeV. We have studied the effects of three different gluon-shadowing parametrizations, using the usual simplified kinematics for which the momentum of the gluon recoiling against the J/psi is neglected as well as an exact kinematics for a 2->2 process; namely g+g->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 antishadowing peak, is systematically shifted toward larger rapidities in the 2->2 kinematics, irrespective of which shadowing parametrization is used. In turn, we have noted differences in the effective final-state nuclear absorption needed to fit the PHENIX dAu data. Taking advantage of our implementation of 2->2 kinematics, we have also computed the transverse momentum dependence of the nuclear modification factor, which cannot be predicted with the usual simplified kinematics. All the corresponding observables have been computed for CuCu and AuAu collisions and compared to the PHENIX and STAR data. Finally, we have extracted the effective nuclear absorption from the recent measurements of R{sub CP} in dAu collisions by the PHENIX collaboration.

Ferreiro, E. G. [Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Fleuret, F. [Laboratoire Leprince Ringuet, Ecole polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Lansberg, J. P. [Centre de Physique Theorique, Ecole polytechnique, CNRS, F-91128 Palaiseau (France); SLAC National Accelerator Laboratory, Theoretical Physics, Stanford University, Menlo Park, California 94025 (United States); Rakotozafindrabe, A. [IRFU/SPhN, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France)

2010-06-15

141

Radiation Effects and Hardening Techniques for Spacecraft Microelectronics  

NASA Astrophysics Data System (ADS)

The natural radiation from the Van Allen belts, solar flares, and cosmic rays found outside of the protection of the earth's atmosphere can produce deleterious effects on microelectronics used in space systems. Historically civil space agencies and the commercial satellite industry have been able to utilize components produced in special radiation hardened fabrication process foundries that were developed during the 1970s and 1980s under sponsorship of the Departments of Defense (DoD) and Energy (DoE). In the post--cold war world the DoD and DoE push to advance the rad--hard processes has waned. Today the available rad--hard components lag two-plus technology node generations behind state- of-the-art commercial technologies. As a result space craft designers face a large performance gap when trying to utilize available rad--hard components. Compounding the performance gap problems, rad--hard components are becoming increasingly harder to get. Faced with the economic pitfalls associated with low demand versus the ever increasing investment required for integrated circuit manufacturing equipment most sources of rad--hard parts have simply exited this market in recent years, leaving only two domestic US suppliers of digital rad--hard components. This paper summarizes the radiation induced mechanisms that can cause digital microelectronics to fail in space, techniques that can be applied to mitigate these failure mechanisms, and ground based testing used to validate radiation hardness/tolerance. The radiation hardening techniques can be broken down into two classes, Hardness By Process (HBP) and Hardness By Design (HBD). Fortunately many HBD techniques can be applied to commercial fabrication processes providing space craft designer with radiation tolerant Application Specific Integrated Circuits (ASICs) that can bridge the performance gap between the special HBP foundries and the commercial state-of-the-art performance.

Gambles, J. W.; Maki, G. K.

2002-01-01

142

Hardenability of aluminum-lithium alloys  

Microsoft Academic Search

With the development of aircraft engineering the number of aluminum-lithium alloys is growing substantially. However, in determining the domain of their application data on the stability of the solid solution and the hardenability should be taken into account. A frequent mistake is the use of an alloy with low stability of the solid solution for preparing thick-walled semifinished products, for

G. L. Shneider; A. M. Drits

1995-01-01

143

The influence of texture on strain hardening  

SciTech Connect

It is well known that the strain hardening behavior of metals is not the same in tension, compression, torsion and rolling, for example. We report on a new set of experiments, comprising wire-drawing interrupted by tensile tests, free compression, channel-die compression, and short-tube torsion in aluminum, an Al-Mg alloy, copper, silver, and 70:30 brass. The texture was measured before straining and at vonMises strain levels of roughly 1.0 and 2.0. Computer simulations of the deformation starting from a set of random grains weighted by observed initial texture, predicted deformation textures in qualitative agreement with the observed ones in most cases. Quantitatively the simulations yielded the Taylor factors as a function of strain for all paths and, with an assumed hardening law for the representative grain, the macroscopic stress/strain curves. The grain hardening rate as a function of resolved shear stress was described in tabular form such as to match one of the macroscopic curves, and then used to predict the others. The eventual fit was quite good; we will describe what judgments needed to be made to achieve this result. The conclusion is that the strain-path dependence of work hardening can be explained simply as a consequence of texture development. 13 refs., 5 figs., 1 tab.

Kocks, U.F.; Stout, M.G.; Rollett, A.D.

1988-01-01

144

Laser transformation hardening of tempered 4340 steel  

NASA Astrophysics Data System (ADS)

A CO2 laser with a fixed laser power of 1.8 KW was employed to harden the surface of some AISI 4340 steel specimens, with a scan rate from 5 to 10 mm/s. The influence of scan rates and tempering treatments of the alloy on the hardness profile and microstructure of the laserhardened zone was analyzed. Microstructures in the hardened zone consisted of mainly lath and twinned martensites. However, depending on the scan rate, autotempered martensite has also been found. In the transition zone of laser-treated specimens, partially dissolved carbides with austenite envelopes and/or austenite islands in a matrix of martensite were observed. The time required for complete carbide dissolution into austenite during laser treatment depended on the tempering conditions. A lower tempering temperature of the alloy produced a deeper hardened zone and a narrower transition zone in the hardness profile. A simple mathematical estimation of the hardness profile, based on the carbon diffusion distance in austenite, was performed. The calculated results are in reasonably good agreement with the measured hardness profiles and the microstructural observations in the laser transformation hardening process.

Shiue, R. K.; Chen, C.

1992-01-01

145

The radiation hardening of communication equipment  

Microsoft Academic Search

The hardening of communication equipment against ionizing and electromagnetic radiation is examined with reference to the effects of nuclear explosions, the operation of nuclear power plants, and the effects of radiation on spacecraft systems. Published studies concerning the effects of ionizing radiation on communication equipment (circuits, networks, and semiconductor components) are reviewed. Particular consideration is given to the main characteristics

L. O. Myrova; A. Z. Chepizhenko

1983-01-01

146

On the Optimization of Compressibility and Hardenability of Sinter-Hardenable PM Steels  

NASA Astrophysics Data System (ADS)

Sinter-hardenable steel powders eliminate the extra steps normally required for heat treating since they allow for direct quenching of components at the end of the sintering cycle with a forced convection cooling unit. The current article presents the results of the effect of the alloying method on the optimization of compressibility and sinter-hardenability of sinter-hardenable PM steels. Water-atomized steel powders were produced. Two successive designs of experiments were used to optimize the chemical composition with prealloyed (nickel, chromium, molybdenum, and manganese) and admixed elements (nickel, chromium, manganese, and copper). Static mechanical properties were also characterized. Results show that among all of the combinations of chemical elements and within the range of concentrations studied, the optimum sinter-hardenable powder had the following prealloyed chemistry: 1.5 wt pct Ni, 1 to 1.25 wt pct Mo, and 0.40 to 0.55 wt pct Cr.

Giguère, Nicolas; Blais, Carl

2013-10-01

147

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

148

Inorganic ions in cold-hardiness.  

PubMed

Cold exposure and freezing may affect ion distribution in several ways and reduce physiologically important ionic gradients. Both freeze-avoiding and freeze-tolerant organisms have developed mechanisms to handle this stress. Supercooled insects seem to be able to maintain their ionic gradients even at temperatures far below zero. When freeze-tolerant insects freeze, ions diffuse down their concentration gradients across the cell membranes and reach electrochemical equilibrium. They quickly reverse this transmembrane diffusion when they are thawed. Trace metals may affect mechanisms for cold-hardening in different ways and reduce cold-hardiness. Freezing may give rise to toxic concentrations of metal ions, and freeze-tolerant organisms probably need to inactivate toxic trace metals. Ice nucleating agents may be important in this context. PMID:15094089

Zachariassen, Karl Erik; Kristiansen, Erlend; Pedersen, Sindre Andre

2004-04-01

149

COLD TRAP  

DOEpatents

An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

Milleron, N.

1963-03-12

150

Laser hardening of diesel engine valve  

SciTech Connect

Results are presented of a complex investigation of the effect of laser treatment on the structure and properties of steel 40Kh10S2M and of engine tests with diesel engine valves hardened by the newly devised technology. Results of the investigation of the microstructure of steel 40Kh10S2M, heat-treated by a laser beam, showed that when a specimen is hardened with fusion of the surface layer, it contains two distinct zones of laser action. Results of the effect of laser treatment on the fatigue limit and the wear resistance of the steel and engine tests permit the conclusion that the suggested method of treating valves of internal engine valve gear has good prospects.

Androsov, A.P.; Aleksenko, S.I.; Boyarkin, M.V.; Kusidis, V.G.; Petrov, V.I.

1988-07-01

151

Numerical simulation of irradiation hardening in Zirconium  

NASA Astrophysics Data System (ADS)

A phase field model is developed to simulate interactions between gliding dislocations and irradiation induced damage loops (i.e., vacancy and self-interstitial loops) in Zirconium. Pinning contact interactions and long-range elastic interactions are simulated, with populations of defects generated based on experimental observations of typical damage microstructures in irradiated Zr. The model is employed to simulate irradiation hardening as a function of damage loop density. We find that the stress fields of damage loops contribute significantly to their effective obstacle strength, and that the elastic interactions cause the dependence of critical resolved shear stress on damage loop number density to deviate from analytical predictions of dispersed barrier hardening. The simulation predictions of the yield strength agree well with experimental measurements for different damage loop densities.

Boyne, A.; Shen, C.; Najafabadi, R.; Wang, Y.

2013-07-01

152

Radiation-hardened optoelectronic components - Detectors  

NASA Astrophysics Data System (ADS)

Recent research in the area of radiation-hardened optical detectors are surveyed. Conventional silicon photodiode structures, special radiation-hardened silicon photodiodes, and special double heterojunction AlGaAs/GaAs photodiodes are studied in neutron, gamma, pulsed X-ray and charged particle environments. Results are studied of this work and other research in this area are presented. These studies have shown that detectors can be made to function acceptably after exposures to neutron fluences of 10 to the 15th n/sq cm, total dose gamma exposures of 10 to the 8th rad (Si), and flash X-ray environments of 10 to the 8th rad/sec (Si). Detector structures that can operate through these conditions, prerad and postrad operational characteristics, and experimental conditions that produced these results are described.

Wiczer, James J.

1986-01-01

153

Contact allergy to aziridine paint hardener.  

PubMed

A painter experienced an extensive dermatitis when exposed to a paint primer (undercoating) used to protect wood siding. The primer was an acrylic emulsion with a polyfunctional aziridine added as a self-curing cross-linker or hardener. The polyfunctional aziridine cross-linker was made by reacting propyleneimine with a polyfunctional acrylate, trimethylolpropane triacrylate (TMPTA). Our patient reacted to the cross-linker and also reacted to TMPTA, which is present in excess in the cross-linker. He also cross-reacted to pentaerythritol triacrylate (PETA). Both TMPTA and PETA can be used in the production of aziridine hardeners and both are well known as sensitizers in radiation-dried acrylic printing inks and coatings. PMID:3156563

Cofield, B G; Storrs, F J; Strawn, C B

1985-03-01

154

Cold War  

NSDL National Science Digital Library

Cold War is a major, 24-part series directed by renowned documentary filmmaker Jeremy Isaacs that recently premiered on CNN and BBC2. Whether or not this series will become "the definitive account of the Cold War" remains to be seen, but the research that has made it possible is quite impressive. This feature-filled, comprehensive site complements the series by offering, among other things, video previews and multimedia recaps of each episode; video, audio, and text excerpts from nearly 100 interviews filmed for the series; text from archival documents and contemporaneous Time and Russian newspaper stories; in-depth sections on Cold War culture; and a Knowledge Bank section containing a glossary, "Cold Warrior" profiles, related links, and a chronology. Additional resources include a classroom guide to the series, online Shockwave quiz games, and an online discussion group. As large as it is now, the site will continue to expand and add new features as the series progresses over the next three months.

155

Ultrastructural Changes during Swelling and Contraction of Mitochondria from Cold-hardened and Non-hardened Winter Wheat.  

PubMed

Mitochondria isolated from both 2 and 24 C grown winter wheat (Triticum aestivum L.) undergo spontaneous swelling in isomolar KCI solutions, but only 24 C mitochondria exhibit a substrate-induced contraction response. Electron microscopic examination revealed that 24 C mitochondria have more clearly defined cristae, less matrix material, and are generally more electron-dense than 2 C mitochondria. During swelling, the matrix material of both 2 and 24 C mitochondria expands and the mitochondria become less electron-dense. After partial swelling, 24 C mitochondria contract upon addition of succinate, and regain structural characteristics similar to those of untreated mitochondria. In contrast, mitochondria from 2 C seedlings continue to swell after addition of substrate, and many of the mitochondria become irregular in shape and lose much of their matrix material. A comparison of results obtained from absorbancy measurements, electron microscopy, and a Coulter Counter indicate that swelling and contraction involve changes both in over-all volume, and internal structural characteristics of mitochondria from 2 and 24 C grown seedlings. Electron microscopic examination of shoot cells showed that mitochondria in 24 C grown seedlings possessed more recognizable cristae and greater internal organization than mitochondria in 2 C seedlings. PMID:16659827

Pomeroy, M K

1977-02-01

156

Fingerprint Hardening with Randomly Selected Chaff Minutiae  

Microsoft Academic Search

Since fingerprints provide a reliable alternative for traditional password based security systems, they gain industry and\\u000a citizen acceptance. However, due to the higher uncertainty and inherent complexity associated with biometrics, using pure\\u000a biometric traits does not present a reliable security system especially for large populations. This paper addresses this problem\\u000a by proposing a hardening scheme which combines the fingerprint minutiae-based

Alper Kanak; Ibrahim Sogukpinar

2007-01-01

157

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

158

Atmospheres for the hardening of steel  

Microsoft Academic Search

Since time immemorial, atmospheres in one form or another have been used to protect steel surfaces against degradation or to impart properties that would otherwise be unobtainable. For a heat-treatment operation that includes both clean-hardening and carburizing, the most viable atmosphere option is a combination of both cryogenic nitrogen for safety purges, and on-site generation of nitrogen--membrane or PSA--and methanol.

Walton

1995-01-01

159

Radiation Hardened P-Surface Channel CCD's  

Microsoft Academic Search

A process for total dose hardening of surface p-channel CCD's with overlapping polysilicon gates has been developed by optimizing the process steps associated with the gate oxides and polysilicon gates. 16-bit shift registers fabricated with this process can be operated up to 1??106 rads (Si) with threshold voltage shifts of ¿ 2V for the buried gates, and ¿ 1.5V for

C. P. Chang

1976-01-01

160

Radiation hardened p-surface channel CCD's  

Microsoft Academic Search

A process for total dose hardening of surface p-channel CCD's with overlapping polysilicon gates has been developed by optimizing the process steps associated with the gate oxides and polysilicon gates. 16-bit shift registers fabricated with this process can be operated up to 1 Mrad (Si) with threshold voltage shifts not above 2V for the buried gates, and not above 1.5V

C. P. Chang

1976-01-01

161

Factors affecting the inherent hardenability of steel  

Microsoft Academic Search

The hardenability of a steel depends upon the actual rate at which its austenite transforms to fine pearlite at the particular\\u000a temperature at which this reaction sets in most promptly. The precise temperature at which this transformation rate is greatest\\u000a depends upon the composition of the steel; in any case, it is this maximum rate at temperatures near 950 degrees

Edgar Collins Bain

1979-01-01

162

Rapid determination of mercury species in sewage sludge by high-performance liquid chromatography on-line coupled with cold-vapor atomic-fluorescence spectrometry after ultrasound-assisted extraction.  

PubMed

So far, no research has been focused on the determination of organomercuries in sewage sludge. Here, an ultrasonic extraction method for the rapid determination of methylmercury (MeHg) and ethylmercury (EtHg) in sewage sludge after ultrasound-assisted extraction is proposed. Using TMA (tetramethylammonium hydroxide) as the extractant with 3.0 g copper powder, ultrasonic extraction for 30 min at 70 °C demonstrated to be highly efficient, and was shown a satisfied extraction efficiency for MeHg and EtHg from sewage sludge samples. Determination of mercury species was carried out by high-performance liquid chromatography on-line coupled with cold-vapor atomic fluorescence spectrometry (HPLC-CV-AFS). The obtained results from quality control samples were excellent. The proposed method was also validated by the application to five real samples. The results showed that the developed methodology was practicable and highly reliable. Due to the high toxicity of organomercuries and huge amounts of sewage sludge discharged every year, people should pay particular attention to pollutions from sewage sludge. PMID:21666362

Gao, Erle; Liu, Jianshe

2011-01-01

163

Novel circuits for radiation hardened memories  

SciTech Connect

This paper reports on implementation of large storage semiconductor memories which combine radiation hardness with high packing density, operational speed, and low power dissipation and require both hardened circuit and hardened process technologies. Novel circuits, including orthogonal shuffle type of write-read arrays, error correction by weighted bidirectional codes and associative iterative repair circuits, are proposed for significant improvements of SRAMs' immunity against the effects of total dose and cosmic particle impacts. The implementation of the proposed circuit resulted in fault-tolerant 40-Mbit and 10-Mbit monolithic memories featuring a data rate of 120 MHz and power dissipation of 880 mW. These experimental serial-parallel memories were fabricated with a nonhardened standard CMOS processing technology, yet provided a total dose hardness of 1 Mrad and a projected SEU rate of 1 [times] 10[sup [minus] 12] error/bit/day. Using radiation hardened processing improvements by factors of 10 to 100 are predicted in both total dose hardness and SEU rate.

Haraszti, T.P.; Mento, R.P. (Microcirc Associates, Newport Beach, CA (United States)); Moyer, N.E. (Hughes Aircraft (United States)); Grant, W.M. (AMI-Gould (United States))

1992-10-01

164

Stage IV work hardening in cubic metals  

SciTech Connect

The work hardening of fcc metals at large strains is discussed with reference to the linear stress-strain behavior often observed at large strains and known as Stage IV. The experimental evidence shows that Stage IV is a work hardening phenomenon that is found quite generally, even in pure fcc metals subjected to homogeneous deformation. A simple model for Stage IV in pure metals is presented, based on the accumulation of dislocation debris. Experiments are described for large strain torsion tests on four aluminum alloys. The level and extent of Stage IV scaled with the saturation stress that would represent the end of Stage III in the absence of a Stage IV. Reversing the torsion after large prestrains produced transient reductions in the work hardening. The strain rate sensitivity was also measured before and during the transient and found not to vary significantly. The microstructure observed at large strains in an Mg alloy suggest that Stage IV can occur in the absence of microband formation. Previous proposals for the cause of Stage IV are reviewed and found to be not supported by recent experimental data.

Rollett, A.D.; Kocks, U.F.; Doherty, R.D.

1986-01-01

165

Strain hardening in underaged INCONEL 718  

SciTech Connect

INCONEL 718 is a commercial, precipitation-hardenable nickel iron-base superalloy, strengthened primarily by precipitates of the metastable [gamma][double prime] phase which is based on the composition Ni[sub 3]Nb and has an ordered body-centered tetragonal (DO[sub 22]) structure. An earlier investigation on the deformation mechanisms in this alloy has shown that [gamma][double prime] precipitates are sheared by the passage of true crystallographic twins (which do not destroy the ordered atomic arrangements within precipitate crystals) when the [gamma][double prime] particle size is larger than about 10 nm. In a situation where the precipitate size is smaller than about 10 nm, the deformation occurs by the passage of quadruplets or pairs of dislocations which shear the [gamma][double prime] particles. The change in the deformation mechanism from dislocation cutting to twinning with increasing [gamma][double prime] particle size is reflected in a drop in the value of the Croussard-Jaoul work-hardening exponent (from 0.8 to 0.5) which has been attributed to the easy propagation of deformation twins within the particles. The present communication reports the results of a study carried out on the characterization of the deformation microstructure of underaged INCONEL 718. An attempt has been made to explain the work-hardening behavior of the alloy in the light of transmission electron microscopic (TEM) observations on its deformation microstructures in the underaged condition.

Sundararaman, M.; Kishore, R.; Mukhopadhyay, P. (Bhabha Atomic Research Centre, Bombay (India))

1994-03-01

166

Dermatitis from aziridine hardener in printing ink.  

PubMed

13 of 51 workers developed dermatitis of the hands and face after handling a water-based ink containing a polyfunctional aziridine hardening agent. Improper work practices resulted in skin contamination with the ink and its ingredients. The aziridine hardener contained trimethylolpropane triacrylate (TMPTA). The incidence of dermatitis was highest among the ink mixers who handled the undiluted aziridine (6 of 8 workers affected), was lower among printers who handled ink containing 2 to 4% aziridine (7 of 22 workers affected), and was absent in workers who did not handle ink. The mean latency from first contact with the ink to the development of the rash was 3.2 months among the ink mixers, and 6.2 months among the printers. The present findings demonstrate the risk of handling aziridine hardeners when protective clothing is not properly used and when work practices result in direct skin contact. Further research should be performed to discern whether aziridine compounds themselves, free of TMPTA, can cause dermatitis. PMID:3160531

Garabrant, D H

1985-04-01

167

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

168

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

169

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

170

Strain age hardening in Fe1 at. % Mn alloy  

Microsoft Academic Search

Tensile tests for wires of Fe?1 at. % Mn alloy have shown the existence of a hardening mechanism”; in the temperature range 200–400°C. Analysis of the results using transmission electron microscopy showed that this hardening is due to the formation and migration of manganese nitride and manganese carbide precipitates in the matrix. Work?hardening characteristics were also determined for wires pre?deformed

T. H. Youssef; G. Saad

1980-01-01

171

Influence of alloy composition on the hardening of silver-tin dental amalgam.  

PubMed

The objective of the investigation was to examine the reactions of mercury with silver-tin alloys with compositions spanning the phase fields beta, (beta + gamma), gamma, and (gamma + Sn). The experimental methods employed include the application of light microscopy, scanning electron microscopy, and electron probe microanalysis. These techniques were used to investigate the mechanisms of reaction and to identify the nature and morphology of the reaction products formed on bulk specimens of the alloys. The progress and characteristics of the reactions that occur during hardening of amalgams prepared from powders of these alloys were monitored using a high-sensitivity dilatometer. These results were correlated with direct observations on the development of the microstructures. The reaction of mercury with the beta-phase alloy occurred rapidly and resulted in a very marked and rapid expansion during the initial stages of hardening. gamma-Phase alloys, on the other hand, reacted more slowly and contracted markedly during hardening. The behavior of amalgams made from alloys with compositions lying between these two extremes appeared to be explicable in terms of the characteristics of the separate phases from which they were constituted. PMID:3782188

Abbott, J R; Miller, D R; Netherway, D J

172

BUSFET -- A radiation-hardened SOI transistor  

SciTech Connect

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 amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, the authors propose a partially-depleted SOI transistor structure for mitigating the effects of trapped charge in the buried oxide on radiation hardness. They call this structure the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU or dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration, and the depth of the source. 3-D simulations show that for a body doping concentration of 10{sup 18} cm{sup {minus}3}, a drain bias of 3 V, and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3 x 10{sup 17} cm{sup {minus}3}, a thicker silicon film (300 nm) must be used.

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

1999-12-01

173

Radiation-hardened N (+) gate CMOS/SOS  

NASA Astrophysics Data System (ADS)

Process development work for a hardened N+ polysilicon-gate CMOS/SOS process has demonstrated that it is possible to make functional 4K CMOS/SOS static RAMs that are hard to 5 x 10 to the 5th power rads without the implementation of special hardened circuit design techniques. Present circuit probe yields are low, limited by the lack of a hardened low-temperature contoured field oxide. Independent research has shown that a hardened reflow process is possible for such field oxides. Development of this reflow process is nearly complete and should result in significant improvement in yields when fully integrated into the rad-hard N+ process.

Hughes, G. W.; Brucker, G. J.; Smeltzer, R. K.

1981-05-01

174

Photoactive coating for hardening optical fibers  

SciTech Connect

In accordance with the foregoing principles and objects of the present invention, an improved optical fiber structure is provided which is hardened against the effects of ionizing nuclear radiation and comprises a conventional plastic, glass or silica optical fiber core and cladding, having an additional outer coating comprising phosphorescent or luminescent material for interacting with the ionizing radiation to provide a source of light to optically bleach the fiber core of optical absorption sites produced as a result of the interaction of the ionizing radiation with the fiber core material.

Caldwell, R.S.

1982-07-29

175

Magnetic Hardening Induced by Nonmagnetic Organic Molecules  

NASA Astrophysics Data System (ADS)

We reveal for the first time through a theoretical first-principles study that the adsorption of a nonmagnetic ?-conjugated organic molecule on a ferromagnetic surface locally increases the strength of the magnetic exchange interaction between the magnetic atoms binding directly to the molecule. This magnetic hardening effect leads to the creation of a local molecular mediated magnetic unit with a stable magnetization direction and an enhanced barrier for the magnetization switching as compared to the clean surface. Remarkably, such a hybrid organic-ferromagnetic system exhibits also a spin-filter functionality with sharp spin-split molecularlike electronic features at the molecular site.

Callsen, Martin; Caciuc, Vasile; Kiselev, Nikolai; Atodiresei, Nicolae; Blügel, Stefan

2013-09-01

176

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

177

Enabling strain hardening simulations with dislocation dynamics  

NASA Astrophysics Data System (ADS)

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 {\\mathcal O}(N) calculation of forces, the equations of motion, time integration, adaptive mesh refinement, the treatment of dislocation core reactions and the dynamic distribution of data and work on parallel computers. A simulation integrating all these algorithmic elements using the Parallel Dislocation Simulator (ParaDiS) code is performed to understand their behaviour in concert and to evaluate the overall numerical performance of dislocation dynamics simulations and their ability to accumulate percent of plastic strain.

Arsenlis, A.; Cai, W.; Tang, M.; Rhee, M.; Oppelstrup, T.; Hommes, G.; Pierce, T. G.; Bulatov, V. V.

2007-09-01

178

Induced cold-tolerance mechanisms depend on duration of acclimation in the chill-sensitive Folsomia candida (Collembola).  

PubMed

During cold periods ectotherms may improve low temperature tolerance via rapid cold hardening (RCH) over a period of hours and/or long-term cold acclimation (LTCA) during days, weeks or months. However, the effect of duration and the major underlying mechanisms of these processes are still not fully understood. In the present study, the molecular and biochemical responses to RCH (1-3 h) and LTCA (1-3 days) and the corresponding benefits to survival were investigated using the chill-sensitive collembolan Folsomia candida. We investigated osmolyte accumulation, membrane restructuring and transcription of candidate genes as well as survival benefits in response to RCH and LTCA. RCH induced significant upregulation of targeted genes encoding enzymes related to carbohydrate metabolic pathways and genes encoding small and constitutively expressed heat shock proteins (Hsps), indicating that the animals rely on protein protection from a subset of Hsps during RCH and probably also LTCA. The upregulation of genes involved in carbohydrate metabolic processes initiated during RCH was likely responsible for a transient accumulation of myoinositol during LTCA, which may support the protection of protein and membrane function and structure. Membrane restructuring, composed especially of a significantly increased ratio of unsaturated to saturated phospholipid fatty acids seems to be a mechanism supplementary to activation of Hsps and myoinositol accumulation in LTCA. Thus, the moderate increase in cold shock tolerance conferred by RCH seems to be dominated by effects of Hsps, whereas the substantially better cold tolerance achieved after LTCA is dominated by post-transcriptional processes increasing membrane fluidity and cryoprotectant concentration. PMID:23393277

Waagner, Dorthe; Holmstrup, Martin; Bayley, Mark; Sørensen, Jesper G

2013-02-07

179

COLD TRAPS  

DOEpatents

A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

Thompson, W.I.

1958-09-30

180

Cold Urticaria  

PubMed Central

Sera were obtained from the venous effluents of cold-challenged arms of patients with idiopathic cold urticaria without plasma or serum cryoproteins; these sera exhibited increased neutrophil chemotactic activity without alterations of the complement system. A two- to fourfold augmentation of the base-line neutrophil chemotactic activity of serum from the immersed extremity began within 1 min, peaked at 2 min, and returned to base-line levels within 15 min, whereas there was no change in the serum chemotactic activity in the control arm. The augmented chemotactic activity in the serum specimens from the challenged arm of each patient appeared in a high molecular-weight region, as assessed by the difference in activity recovered after Sephadex G-200 gel filtration of the paired lesional and control specimens. Sequential purification of this high molecular-weight activity by anion- and cation-exchange chromatography revealed a single peak of activity at both steps. The partially purified material continued to exhibit a high molecular weight, being excluded on Sepharose 4B, and had a neutral isoelectric point. The partially purified material showed a preferential chemotactic activity for neutrophilic polymorphonuclear leukocytes, required a gradient for expression of this function, and exhibited a capacity to deactivate this cell type. This active principle, termed high molecular-weight neutrophil chemotactic factor, exhibited a time-course of release that could be superimposed upon that of histamine and the low molecular-weight eosinophil chemotactic factor and may represent another mast cell-derived mediator.

Wasserman, Stephen I.; Soter, Nicholas A.; Center, David M.; Austen, K. Frank

1977-01-01

181

A fuzzy approach for induction hardening parameters selection  

Microsoft Academic Search

In this study, department of case hardness is controlled by using certain parameters which are optimized by fuzzy logic determining certain parameters of induction surface hardening.Many parameters influence hardness depth such as coil dimensions, electrical voltage and current, material type, cooling rate, etc. All parameters effecting to the induction hardening are fuzzified. Base width of the membership function for certain

Mehmet Cengiz Kayacan; O?uz Çolak

2004-01-01

182

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

183

Design of a 1 Gb Radiation Hardened NAND flash memory  

Microsoft Academic Search

Non-volatile memories used in the space environment typically require radiation hardened process technologies. These technologies are not only costly, but the resultant die occupies more area compared to commercial memories of comparable size. This in turn limits the memory density of these radiation hardened memories. In this paper, we present a technique for the development of a low cost 1

Nikhil Gupta; Bert Vermeire; Hugh Barnaby; Murat Goksel; Edward Li; David Czajkowski

2007-01-01

184

Contamination Hardening of SU-31 and FS-85 Columbium Alloys.  

National Technical Information Service (NTIS)

A study has been made of the contamination hardening of SU-31 and FS-85 columbium alloys which results when samples are exposed in air temperatures of 1400 to 2600 F. Diffusion coefficients for the principal contaminant, calculated from hardening profiles...

R. B. Herring

1973-01-01

185

Improving the properties of cold-rolled Al–6%Ni sheets by alloying and heat treatment  

Microsoft Academic Search

The mechanical properties of a cold-rolled binary eutectic Al–Ni alloy can be considerably improved by additional alloying with Zr and heat treatment of a billet. Two-stage annealing of billets results in the favourable morphology changes in the eutectics structure and in the substantial hardening with participation of Al3Zr dispersoids. The cold-rolled material starts to soften only at temperatures as high

N. A. Belov; A. N. Alabin; D. G. Eskin

2004-01-01

186

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

187

Inelastic Cyclic Instability of 2024-T4 Aluminum and Cold-Rolled 1020 Steel.  

National Technical Information Service (NTIS)

An investigation was made into the cyclic instabilities of cyclic strain hardening and cyclic strain softening materials. 2024-T4 aluminum and cold-rolled 1020 steel were selected respectively. Specimens had fixed ends with a slenderness ratio l/r equal t...

C. R. Prischmann R. I. Stephens

1971-01-01

188

Hardness survey of cold-worked and heat-treated JBK-75 stainless steel alloy  

Microsoft Academic Search

The alloy JBK-75, an age-hardenable austenitic stainless steel, is similar to commercial A-286, but has certain chemistry modifications to improve weldability and hydrogen compatibility. The principal changes are an increase in nickel and a decrease in manganese with lower limits on carbon, phosphorus, sulfur, silicon, and boron. In this study, the effects of solutionizing time and temperature, quench rate, cold

R. J. Jackson; R. L. Lucas

1977-01-01

189

Novel SEU hardened PD SOI SRAM cell  

NASA Astrophysics Data System (ADS)

A novel SEU hardened 10T PD SOI SRAM cell is proposed. By dividing each pull-up and pull-down transistor in the cross-coupled inverters into two cascaded transistors, this cell suppresses the parasitic BJT and source-drain penetration charge collection effect in PD SOI transistor which causes the SEU in PD SOI SRAM. Mixed-mode simulation shows that this novel cell completely solves the SEU, where the ion affects the single transistor. Through analysis of the upset mechanism of this novel cell, SEU performance is roughly equal to the multiple-cell upset performance of a normal 6T SOI SRAM and it is thought that the SEU performance is 17 times greater than traditional 6T SRAM in 45nm PD SOI technology node based on the tested data of the references. To achieve this, the new cell adds four transistors and has a 43.4% area overhead and performance penalty.

Chengmin, Xie; Zhongfang, Wang; Xihu, Wang; Longsheng, Wu; Youbao, Liu

2011-11-01

190

Laser hardening process simulation for mechanical parts  

NASA Astrophysics Data System (ADS)

In this paper a numerical simulation of laser hardening process is presented. The Finite Difference Method (FDM) was used to solve the heat transfer and the carbon diffusion equations for a defined workpiece geometry. The model is able to predict the thermal cycle into the target material, the phase transformations and the resulting micro-structures according to the laser parameters, the workpiece dimensions and the physical properties of the workpiece. The effects of the overlapping tracks of the laser beam on the resulting micro-structures is also considered. The initial workpiece micro-structure is taken into account in the simulation by a digitized photomicrograph of the ferrite perlite distribution before the thermal cycle. Experimental tests were realized on a C43 plate and the good agreement between the theoretical and experimental results is shown.

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

2007-03-01

191

Ionizing radiation hardening of a CCD technology  

NASA Astrophysics Data System (ADS)

A three-level polysilicon, buried channel charge coupled device (CCD) technology has been tested for Co-60 ionizing radiation damage up to a total dose of 90 krad(Si). For this purpose CCD image sensors have been irradiated together with their associated test structures. These include different types of MOSFETs, natural transistors, buried channel transistors, field transistors, and diodes. The devices have been fully characterized during irradiation and afterwards, as a function of time. The standard technology has been assessed, leading to the implementation of process and design modifications. The modified technology has been further tested according to the same procedure and significant improvement in the sensors' behavior under irradiation and during annealing has been observed. The radiation hardness of the CCDs has been correlated with the results of the test structures, allowing a better understanding of the degradation phenomena and of the countermeasures needed for a radiation-hardened technology.

Simone, A.; Debusschere, I.; Alaerts, A.; Claeys, C.

1992-12-01

192

Cold tolerance of the Australian spur-throated locust, Austracris guttulosa.  

PubMed

The cold tolerance of overwintering adult Spur-throated locusts, Austracris guttulosa, was examined using measures of supercooling point relative to gender, environmental acclimation and feeding state as well as mortality for a range of sub-zero temperature exposure treatments. Freezing was lethal and supercooling points ranged from -6 to -12.8°C, but were statistically independent of fresh mass, body water content, acclimation, and/or gut content in fed and starved individuals. A significant interaction effect of gender and feeding status showed that the larger bodied females had decreased supercooling capacity with increased food material in the digestive tract. Post-freezing dissections revealed differences in the amount of freshly consumed and retained food material in the digestive tract between fed and starved individuals of each gender, which could explain this effect based on inoculation of ice crystallisation by food particles. Above supercooling temperatures, neither gender nor the rate of cooling had a significant effect on mortality. When cooled from 25°C at 0.1 or 0.5°Cmin(-1) to a range of experimental minimum temperatures held for 3h, survival was ~74% to -7°C, but declined sharply to ~37% when cooled to -8°C or lower. Although the laboratory experiments reported here suggest that A. guttulosa is not freeze tolerant and unable to rapidly cold harden, exposure to typical cold and frosty nights that very rarely reach below -8°C as a night minimum in the field would be unlikely to cause mortality in the vast majority of overwintering aggregations. PMID:22226821

Woodman, James D

2011-12-29

193

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

PubMed Central

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

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

2006-01-01

194

CT image correction for beam hardening using simulated projection data  

SciTech Connect

A general beam-hardening correction technique is presented. This postreconstruction method does not require the original projection data. Simulated projections through an uncorrected reconstructed image are used to correct for beam hardening. Errors in the mean linear attenuation coefficient are decreased from 30% to 5% with virtual elimination of the visual streaking artifact. The theoretical image improvement equals that of projection linearization postreconstruction methods using the original projection data. The correction is limited to cases where the material causing the beam hardening is contained within the reconstruction space.

Meagher, J.M. (Dept. of Mechanical Engineering, California Polytechnic State Univ., San Luis Obispo, CA (US)); Mote, C.D. Jr. (Dept. of Mechanical Engineering, Univ. of California, Berkeley, CA (US)); Skinner, H.B. (Dept. of Orthopedic Surgery, Univ. of California, San Francisco, CA. (US))

1990-08-01

195

Rapid-Setting Controlled Low-Strength Material for Routine and Emergency Rehabilitation of Transportation Materials.  

National Technical Information Service (NTIS)

An experimental investigation of rapid setting controlled low-strength materials (CLSM) mixtures is described in this research report. The setting and hardening times of CLSM batched with concrete accelerators (chloride and non-chloride) were evaluated us...

C. E. Pierce S. Ihekweazu

2004-01-01

196

Medical problems from cold exposure  

SciTech Connect

Problems resulting from cold exposure can be successfully treated when a coordinated emergency medical transport system and appropriate equipment are available, as well as medical personnel knowledgeable in the management of frostbite and hypothermia. Clinical suspicion of these disorders is essential. Profoundly hypothermic individuals with no recordable vital signs have been resuscitated after controlled, rapid rewarming measures and the use of emergency life-support systems.

Dembert, M.L.

1982-01-01

197

Effect of cartolin on oryzalin-induced changes in lectin activity during low-temperature plant hardening  

Microsoft Academic Search

The effect of cartolin (0.33 ?M), an antistress regulator of cytokinin type, on the cytoskeleton-dependent changes in lectin\\u000a activity in the roots of unhardened (23°C) and cold-hardened (3°C, 7 days) 7-day-old plants of three cultivars of winter wheat\\u000a (Triticum aestivum L.) was studied. In unhardened plants, cartolin increased activity of soluble and cell wall-bound lectins in a cultivar-specific\\u000a mode. This

O. A. Timofeeva; L. D. Garaeva; Yu. Yu. Chulkova; L. P. Khokhlova

2008-01-01

198

Facts about the Common Cold  

MedlinePLUS

... Disease > Influenza > In-Depth-Resources Facts About the Common Cold What is a Cold? Colds are minor infections ... are no antiviral medications available for treating the common cold. Antibiotics are not useful for treating a cold, ...

199

Wide Band Receiver Hardening to Radio Frequency Interference.  

National Technical Information Service (NTIS)

The patent application relates to a circuit for hardening wide band receiver performance against interference and jamming. The broad pass band is subdivided into a series of narrow pass band filter segments, each provided with amplitude limiters. The full...

S. W. Lichtman

1976-01-01

200

Feasibility Study and Design of Hardened Evaporative Coolers.  

National Technical Information Service (NTIS)

A study is presented on the feasibility of designing and constructing, for test purposes, an evaporative type cooling system located within an underground shelter hardened to withstand an air-blast overpressure of 600 psi. The study includes the analysis ...

W. B. Koerner W. A. Renner

1970-01-01

201

Prediction of Case Depth in Laser Transformation Hardening.  

National Technical Information Service (NTIS)

An approximate heat flow model is developed to predict the case depth produced by laser transformation hardening of steel surfaces. The model exploits the dimensional relationships between the process variables leading to master diagrams for both Gaussian...

H. R. Shercliff M. F. Ashby

1989-01-01

202

Point defect concentrations and hardening in binary B2 intermetallics  

SciTech Connect

Point defect hardening in binary B2 intermetallic compounds with the anti-structure defect structure (FeCo and AuZn) and the triple defect structure (NiAl, FeAl, and CoAl) was investigated. Thermodynamic modeling combined with experimental measurements of lattice parameters and bulk densities were used to establish point defect concentrations as functions of composition and temperature. Microhardness measurements were made on samples of varying compositions and quenching temperatures. Solution hardening rates of vacancies were found to be significantly larger than those of anti-site defects. It was possible to relate the hardening rates of anti-site defects to the magnitude of the lattice dilation. This suggests that the elastic size effect was the primary hardening mechanism. No such correlation was found for vacancies.

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.

1997-09-01

203

On the Hardening Response in Small Deformation of Metals.  

National Technical Information Service (NTIS)

This paper is concerned with a special class of hardening response functions for small deformation of elastic-plastic materials, its application to isotropic metals, and comparison of the theoretical results with experimental cyclic stress-strain curves. ...

D. A. Caulk P. M. Naghdi

1978-01-01

204

Skydd mot Elektromagnetiska Stoerningar (Hardening Against Electromagnetic Interference),  

National Technical Information Service (NTIS)

Hardening against Electromagnetic Interference is provided by means of Controlled Electromagnetic Topology. Protective measures are systematically optimized in order to achieve a balance between shielding and filtering. Using the concept of the Generalize...

T. Karlsson

1988-01-01

205

Development of cosmic ray hardened power MOSFETs  

SciTech Connect

Developmental power DMOS (double-diffused metal-oxide semiconductor) FETs (field effect transistors) were 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 to applications that cannot compensate for the added performance degradation. Long-term reliability of the gate oxide may be affected resulting in premature device failure. Each failure mode is discussed. Numerous processing lots were fabricated to experimentally verify that each failure mode could be successfully minimized. Test results show that an n-channel, 150-volt DMOS FET was fabricated that survived exposures to ions with LETs up to 80 MeV-cm{sup 2}/mg. Hardening approaches are discussed, including the advantages and disadvantages of each approach on the FETs performance.

Titus, J.L. (Naval Weapons Support Center, Advanced Technology Div., Crane, IN (US)); Jamiolkowski, L.S.; Wheatley, C.F. (Harris Semiconductor, Mountaintop, PA (US))

1989-12-01

206

Weldable, age hardenable, austenitic stainless steel  

DOEpatents

An age hardenable, austenitic stainless steel having superior weldability properties as well as resistance to degradation of properties in a hydrogen atmosphere is described. It has a composition of from about 24.0 to about 34.0 weight percent (w/o) nickel, from about 13.5 to about 16.0 w/o chromium, from about 1.9 to about 2.3 w/o titanium, from about 1.0 to about 1.5 w/ o molybdenum, from about 0.01 to about 0.05 w/o carbon, from about 0 to about 0.25 w/o manganese, from about 0 to about 0.01 w/o phosphorous and preferably about 0.005 w/o maximum, from about 0 to about 0.010 w/o sulfur and preferably about 0.005 w/o maximum, from about 0 to about 0.25 w/o silicon, from about 0.1 to about 0.35 w/o aluminum, from about 0.10 to about 0.50 w/o vanadium, from about 0 to about 0.0015 w/o boron, and the balance essentially iron. (auth)

Brooks, J.A.; Krenzer, R.W.

1975-07-22

207

Cylindrical shell buckling through strain hardening  

SciTech Connect

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

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

1995-04-01

208

Radiation-hardened microwave communications system  

SciTech Connect

The consolidated fuel reprocessing program (CFRP) at the Oak Ridge National Laboratory (ORNL) has been developing signal transmission techniques and equipment to improve the efficiency of remote handling operations for nuclear applications. These efforts have been largely directed toward the goals of (a) remotely controlling bilateral force-reflecting servomanipulators for dexterous manipulation-based operations in remote maintenance tasks and (b) providing television viewing of the work site. In September 1987, developmental microwave transceiving hardware operating with dish antennas was demonstrated in the advanced integrated maintenance system (AIMS) facility at ORNL, successfully implementing both high-quality one-way television transmissions and simultaneous bidirectional digital control data transmissions with very low error rates. Initial test results based on digital transmission at a 1.0-Mbaud data rate indicated that the error rates of the microwave system were comparable to those of a hardwired system. During these test intervals, complex manipulator operations were performed, and the AIMS transporter was moved repeatedly without adverse effects on data integrity. Results of these tests have been factored into subsequent phases of the development program, with an ultimate goal of designing a fully radiation-hardened microwave signal transmission system for use in nuclear facilities.

Smith, S.F.; Crutcher, R.I.; Vandermolen, R.I. (Oak Ridge National Lab., TN (United States))

1990-01-01

209

Utilisation of sinter-hardening treatment for various sintered steels  

Microsoft Academic Search

Purpose: Purpose of this paper was to present the benefits of powder metallurgy technology and development of sinter-hardening process applied to different steels including pre-alloyed Ni-Mo steels with W addition, Astaloy CrM and experimental sintered duplex stainless steels. The mechanical properties, focusing in particular on hardness and wear resistance, of two different sinter-hardened steels were described. Microstructure characteristic of produced

L. A. Dobrza?ski a; J. Otr?ba; Z. Brytan; M. Rosso

210

Examination of the parameters of pulsed hardening of flat components  

Microsoft Academic Search

Hardening was carried out on SRC-20a flat-grinding machine with a modernized main drive. The width of the working part of the hardening disk (45 steel in the normalized condition) was 14 mm. the linear speed of the circumference 60-65 m\\/sec. The processing media were mineral oil (Industrial'noe20) and a saturated aqueous solution of mineral salts based on magnedium and calcium

Yu. I. Babel; V. V. Shvets; I. V. Gurei; L. A. Kaparova

1989-01-01

211

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

212

Forming limit diagrams for kinematically hardened voided sheet metals  

Microsoft Academic Search

A model to predict forming limit diagrams for kinematically hardened voided sheet metals is established. The model is based on von Mises yield criterion for a void-free matrix material, Gurson–Tvergaard yield criterion for voided solids, and a kinematic-hardening rule due to Prager–Ziegler. A complete formulation of plasticity constitutive laws is given, e.g. yield function, flow rule and void growth law.A

A. R. Ragab; Ch. Saleh; N. N. Zaafarani

2002-01-01

213

Parameters for validation of a NEMP hardened facility  

Microsoft Academic Search

The aim of this theoretical research paper is to bring out the critical aspects of parameters for validation requirements for hardening of a typical C4ISR facility against disruption and damage from electromagnetic pulses (NEMP) produced by nuclear blasts. The purpose of NEMP hardening system is to protect critical military\\/civil systems such as C4ISR facilities \\/ C4I2 systems, Command and control

K. P. Gowd

2008-01-01

214

Free Vibration Analysis of Pyroshock-Loaded Hardened Structures  

Microsoft Academic Search

\\u000a The free vibration response of a high stiffness, high strength (hardened) structural member is characterized under a variety\\u000a of energetic and simulated pyroshock system inputs. The hardened structure studied is a structural pipe which includes a reinforcing\\u000a material, e.g., a composite potting, with threaded end caps. Impulsive loads are imparted on the structure using bulk explosives\\u000a and non-energetic impacts. The

Jason R. Foley; Lashaun M. Watkins; Brian W. Plunkett; Janet C. Wolfson; Preston C. Gillespie; Jeffrey C. Karsen; Alain L. Beliveau

215

Properties of modified anhydride hardener and its cured resin  

Microsoft Academic Search

Methyl-nadic-tetrahydric-methylanhydride (MNA), nadic-tetrahydric-methylanhydride (NA), anhydride hardener was modified by solid diol molecule to improve the impregnation resin fracture toughness in cryogenic temperature. The lap-shear strength, transverse tension as well as the thermal shock test showed that the resin cured by the modified anhydride hardener had higher bond strength and more toughness at 77 K. After the experiment of vacuum pressure

Chen Qiang; Gao Bingjun; Chen Jinglin; X. Tongzhao

2000-01-01

216

Influence of Vanadium on the Hardenability of a Carburizing Steel  

Microsoft Academic Search

The case and core hardenability of a lean alloyed carburizing steel containing microalloying additions of vanadium, molybdenum,\\u000a and titanium have been determined. For comparison purposes a standard SS2506 carburizing steel grade was selected and the\\u000a results have shown similar core hardenability for the two steel types. However, at section sizes above -25 mm the standard\\u000a grade was found to exhibit

Stephen Preston

1990-01-01

217

Evaluating surface hardened steels by laser-acoustics  

Microsoft Academic Search

The use of surface acoustic waves was studied as a means of evaluating surface-hardened steels. Four different grades of steel, 42CrMo4, C45, X153CrMoV12.1 and 90MnCrV8, were laser hardened up to a depth of 1.5mm. The construction of a laser acoustic handheld probe enabled the measurement of the propagation velocity of the surface acoustic waves on large components. The measurement yields

Dieter Schneider; Rainer Hofmann; Thomas Schwarz; Thomas Grosser; Eckehard Hensel

218

Tensile Stress-Strain Modeling of Pseudostrain Hardening Cementitious Composites  

Microsoft Academic Search

This study proposes a new theoretical approach for predicting the tensile stress-strain relation of random short-fiber-reinforced cement composites showing pseudostrain hardening. This approach is grounded on the solid basis of micromechanics, which describes the pseudostrain hardening phenomenon in terms of constitutive properties of the fiber, matrix, and fiber\\/matrix interface. The proposed modeling requires theoretical treatment of an inelastic strain due

Tetsushi Kanda; Zhong Lin; Victor C. Li

2000-01-01

219

[Hardening and softening phenomena in beans: technological alternatives].  

PubMed

The effect of accelerated hardening and soaking solutions on cooking time and microstructure of common bean (Phaseolus vulgaris) was studied. Two varieties (Canario and Mayocoba) were grown in the same location. Three hardening procedures were used: 1) End A. Soaking in acetate buffer, pH = 4.0 at 37 degrees C for 5 hs, 2) End B. Storage at 37 degrees C, 100% RH for 28 days and, 3) End C storage at 13-33 degrees C, 76% RH for 120 days. The salt solutions used for soaking were: Soln 1 (1% NaCl+0.75% NaHCO3) and Soln 2 (0.75% NaHCO3). Cooking times were determined using a Mattson bean cooker. In both varieties, the three hardening procedures decreased (38-50%) cotyledons water holding capacity and increased significantly (2-4 times) cooking times. During soaking in salt solutions hardened beans reached maximum water absorption in four hours. Soaking in salt solutions decreased drastically (2.6-10.6 times) cooking times. Fresh, hardened and softened seeds were examined by light microscopy, observing ultrastructural differences among them. The methods used in this research might well represent the central components of an industrial technological procedure for the utilization of hardened beans. PMID:1342167

Palma-Tirado, M L; Reyes-Moreno, C; Cárabez-Trejo, A; Montes-Rivera, R; Paredes-López, O

1992-09-01

220

Cold Signaling and Cold Response in Plants  

PubMed Central

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

Miura, Kenji; Furumoto, Tsuyoshi

2013-01-01

221

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

222

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.…

Silverthorn, Dee U.; Michael, Joel

2013-01-01

223

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

Microsoft Academic Search

The physiology of the Antarctic microarthropod, Cryptopygus antarcticus, has been well studied, particularly with regard to its ability to withstand low winter temperatures. However, the molecular mechanisms underlying this phenomenon are still poorly understood. 1180 sequences (Expressed Sequence Tags or ESTs) were generated and analysed, from populations of C. antarcticus. This represents the first publicly available sequence data for this

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

2008-01-01

224

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

225

Skin Reactions to Cold  

PubMed Central

Although skin reactions to cold are seen surprisingly infrequently in Canada, it is important to manage them correctly when they do occur. Frostbite, cold urticarias, Raynaud's disease and phenomenon, and several miscellaneous changes are discussed.

Talpash, Orest

1976-01-01

226

Coping with Colds  

MedlinePLUS

... hanging out with someone who is smoking. And people who smoke are more likely to catch colds than people ... cold. Stay clear of smokers, too: even secondhand smoke can make people more likely to get sick. Don't use ...

227

Computer modelling of age hardening for cast aluminium alloys  

NASA Astrophysics Data System (ADS)

Age hardening, or precipitation hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. Although various age hardening models have been developed for aluminium alloys, from the large volume of literature reviewed, it appears that the bulk of the research has been concentrated on wrought aluminium alloys, only a few of the established precipitation models have been applied to the casting aluminium alloys. In the present work, there are two modelling methods that have been developed and applied to the casting aluminium alloys A356 and A357. One is based on the Shercliff-Ashby methodology to produce a process model, by which we mean a mathematical relationship between process variables (alloy composition, ageing temperature and time) and material properties (yield strength or hardness) through microstructure evolution (precipitate radius, volume fraction). The other method is based on the Kampmann and Wagner Numerical (KWN) model which deals with concomitant nucleation, growth and coarsening and is thus capable of predicting the full evolution of the particle size distribution and then a strength model is used to evaluate the resulting change in hardness or yield strength at room temperature by taking into account contributions from lattice resistance, solid solution hardening and precipitation hardening.

Wu, Linda; Ferguson, W. George

2009-08-01

228

Hardening treatment of machine parts with CO2 power lasers  

NASA Astrophysics Data System (ADS)

Two technological laser facilities were built at the All-Union Scientific Research Institute of Electrothermal Equipment for hardening machine parts using 1.2 and 2.5 kW CO2 lasers. Both lasers are continuous wave devices with self sustained gas discharge between flat anode and tubular cathode. Each facility includes a Fabry-Perot resonator, a beam transporting and focusing mechanism, a laser power measuring instrument with a movable beam chopping mirror, and a helium/neon simulating laser with two mirrors for precision alignment of parts. These facilities are intended not only for hardening, but also for annealing, plating, and alloying. Under consideration is also use for welding and cutting. Materials hardenable with these facilities range from perlite iron to chromium steels. Experimentally hardened parts include tool bits, gear teeth, zinc extrusion plungers, bearing races, king pins, bolts, and even diesel cylinders. Hardening is done to ensure high wear resistance of the materials and long service life for the part.

Borodachev, A. S.; Gutman, M. B.; Kuznetsov, G. A.; Medvedovskaya, L. A.; Rubin, G. K.

1986-01-01

229

Texture development and hardening characteristics of steel sheets under plane-strain compression  

SciTech Connect

Crystallographic texture development and hardening characteristics of a hot-rolled, low-carbon steel sheet due to cold rolling were investigated by idealizing the cold rolling process as plane-strain compression. The starting anisotropy of the test material was characterized by examination of the grain structure by optical microscopy and the preferred crystal orientation distribution by x-ray diffraction. Various heat treatments were used in an effort to remove the initial deformation texture resulting from hot rolling. The plastic anisotropy of the starting material was investigated with tensile tests on samples with the tensile axis parallel, 45{degree}, and perpendicular to the rolling direction. The grain structure after plane-strain compression was studied by optical microscopy, and the new deformation texture was characterized by x-ray diffraction pole figures. These figures are compared with the theoretical pole figures produced from a Taylor-like polycrystal model based on a pencil-glide slip system. The uniaxial tensile stress-strain curve and the plane-strain, compressive stress-strain curve of the sheet were used to calibrate the material parameters in the model. The experimental pole figures were consistent with the findings in the theoretical study. The experimental and theoretical results suggest that the initial texture due to hot rolling was insignificant as compared with the texture induced by large strains under plane-strain compression.

Friedman, P.A. [Ford Research Lab., Dearborn, MI (United States); Liao, K.C.; Pan, J. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering and Applied Mechanics; Barlat, F. [Alcoa Technical Center, Alcoa Center, PA (United States)

1999-04-01

230

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

231

Cold spraying: Innovative layers for new applications  

NASA Astrophysics Data System (ADS)

In recent years, results of many studies have been published that enhance understanding of the fundamental mechanisms of cold-spray coating generation and bonding as well as coating characteristics. From the points of view of a job shop in thermal spraying and of a user of cold-spraying equipment, a procedure, being used in development of new applications is presented herein. In addition to the technical requirements, some general factors determining the success of industrial use of spraying are shown. Examples of coldsprayed coatings are described to shos both the possibility of rapid integration of this new technique in established coating jobs as wells as exploration and use of new possibilities in cold spraying and development of applications that have not yet been a focus of thermal spray techniques. Suggestions for further research and development activities are made on the basis of practical cold-spray experience.

Marx, S.; Paul, A.; Köhler, A.; Hüttl, G.

2006-06-01

232

Kinematic Hardening: Characterization, Modeling and Impact on Springback Prediction  

NASA Astrophysics Data System (ADS)

The constitutive modeling of the materials' mechanical behavior, usually carried out using a phenomenological constitutive model, i.e., a yield criterion associated to the isotropic and kinematic hardening laws, is of paramount importance in the FEM simulation of the sheet metal forming processes, as well as in the springback prediction. Among others, the kinematic behavior of the yield surface plays an essential role, since it is indispensable to describe the Bauschinger effect, i.e., the materials' answer to the multiple tension-compression cycles to which material points are submitted during the forming process. Several laws are usually used to model and describe the kinematic hardening, namely: a) the Prager's law, which describes a linear evolution of the kinematic hardening with the plastic strain rate tensor b) the Frederick-Armstrong non-linear kinematic hardening, basically a non-linear law with saturation; and c) a more advanced physically-based law, similar to the previous one but sensitive to the strain path changes. In the present paper a mixed kinematic hardening law (linear + non-linear behavior) is proposed and its implementation into a static fully-implicit FE code is described. The material parameters identification for sheet metals using different strategies, and the classical Bauschinger loading tests (i.e. in-plane forward and reverse monotonic loading), are addressed, and their impact on springback prediction evaluated. Some numerical results concerning the springback prediction of the Numisheet'05 BenchmarkNo.3 are briefly presented to emphasize the importance of a correct modeling and identification of the kinematic hardening behavior.

Alves, J. L.; Bouvier, S.; Jomâa, M.; Billardon, R.; Oliveira, M. C.; Menezes, L. F.

2007-05-01

233

On the hardening and softening of nanocrystalline materials  

SciTech Connect

Nanocrystalline Pd and Cu samples have been thermally treated to determine whether the relation between hardness and grain size depend on the method used to vary the grain sizes. Previous reports indicate that hardening with decreasing grain size resulted from data obtained using individual samples, while softening with decreasing grain size resulted from data from a given sample that had been thermally treated. Hardening and softening regimes were evident for the nanocrystalline cu, and the hardness improvements over the original as-consolidated state were maintained throughout the thermal treatments. This review examines our hardness results for Cu and Pd and those for other nanocrystalline materials.

Fougere, G.E.; Weertman, J.R. (Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering); Siegel, R.W. (Argonne National Lab., IL (United States). Materials Science Div.)

1993-04-01

234

The anisotropic work-hardening of WC crystals  

SciTech Connect

This paper reports that it has been found that indented (1010) surfaces of WC crystals exhibit piled-up material next to the indentations while (0001) surfaces exhibit sunk-in material. Since in some metals sunk-in material around indenters indicates a higher work-hardening capacity than piled-up material, slip line and etch pit patterns around indentations were analyzed, in order to deduce the dislocation reactions occurring in each case. It was found that 1/6(1210) sessile dislocations can be produced only when indenting (0001) surfaces, which is consistent with a higher work-hardening capacity of (0001) surfaces.

Luyckx, S.B.; Nabarro, F.R.N.; Wai, S.W.; James, M.N. (Schonland Research Centre, Condensed Matter Physics Research Unit, Dept. of Metallurgy and Materials Engineering, Univ. of the Witwatersrand, Johannesburg (ZA))

1992-07-01

235

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

236

Laser surface hardening for tooling high-speed steel  

NASA Astrophysics Data System (ADS)

Annealed high speed steels for making tools such as W6Mo5Cr4V2, W9Mo3Cr4V1, W18Cr4V were treated with 5 kw continuous adjusting CO2 laser. By controlling laser- processing parameters, we achieved variable datum about the depth and hardness of the surface hardening layer of the samples. The relationship between the depth of hardening layer and laser processing parameters were studied with microhardness meter, scanning electronic microscope. The results showed that the sample's micro organization was markedly fined, dislocation and twin crystal subconstruction was strikingly increased, its hardness was obviously higher than that of general heat treatment.

Liu, Weina; Bai, Fengming; Zhang, Dongyun; Chen, Ling; Wang, Jingyi; Xia, Yang

1998-08-01

237

Why semiconductors must be hardened when used in space  

SciTech Connect

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

Winokur, P.S.

2000-01-04

238

Hardenability of austenite in a dual-phase steel  

NASA Astrophysics Data System (ADS)

A low-carbon, low-alloy steel was intercritically heat treated and thermomechanically processed to study the martensitic hardenability of austenite present. Rolling of the two-phase (?+?) microstructure elongated austenite particles and reduced their martensitic hardenability because the ?/? interface where new ferrite forms during cooling was increased by the particle elongation. The martensite particles obtained in rolled material were also elongated or fibered in the rolling direction. Therefore, the thermomechanical processing of a two-phase (?+?) mixture has the detrimental effect of increasing the quenching power needed to yield a specific amount of martensite.

Sarwar, M.; Priestner, R.

1999-06-01

239

Atomistic mechanisms of cyclic hardening in metallic glass  

NASA Astrophysics Data System (ADS)

Molecular dynamics with an embedded-atom method potential is used to simulate the nanoindentation of Cu63.5Zr36.5 metallic glasses. In particular, the effects of cyclic loading within the nominal elastic range on the overall strength and plasticity of metallic glass are studied. The simulated results are in line with the characteristics of experimentally observed hardening effects. In addition, analysis based on local von Mises strain suggests that the hardening is induced by confined microplasticity and stiffening in regions of the originally preferred yielding path, requiring a higher applied load to trigger a secondary one.

Deng, Chuang; Schuh, Christopher A.

2012-06-01

240

Hyperbaric Oxygen as an Adjunct Treatment of Freezing Cold Injury.  

National Technical Information Service (NTIS)

Although there is general agreement that the initial treatment of freezing cold injury (FCI) should be rapid rewarming to prevent direct injury from intracellular ice formation and protein denaturation, there is less conformity in the clinical interventio...

I. B. Mekjavic J. Gorjanc P. J. Mekjavic F. Bajrovic M. Milcinski

2005-01-01

241

Effect of storage temperature and duration on cold hardiness and ...  

Treesearch

Description: Electrolyte leakage (EL) has successfully predicted cold hardiness of ... EL has also been performed experimentally on European hardwood species. ... of hardwood seedlings (e.g., seasonal loss of leaves) would result in a rapid, ...

242

Characterization of Steels Using a Revised Kinematic Hardening Model Incorporating Bauschinger Effect.  

National Technical Information Service (NTIS)

A new variant of the nonlinear kinematic hardening model is proposed that accommodates both nonlinear and linear strain hardening during initial tensile loading and reduced elastic modulus during initial load reversal. It also incorporates the Bauschinger...

A. P. Parker E. Troiano J. H. Underwood C. Mossey

2002-01-01

243

The Mechanism of Work-Hardening in F. C. C. Crystals.  

National Technical Information Service (NTIS)

The report gives the results of a theoretical and experimental investigation on the work-hardening mechanism in face centred cubic metals. In the theoretical part some of the existing theories of work-hardening were critically analysed.

G. Schoeck R. Medrano

1966-01-01

244

Use of Hydrated Lime in Bituminous Mixtures to Decrease Hardening of the Asphalt Cement.  

National Technical Information Service (NTIS)

When asphaltic cement hardens, cracking and raveling occur which cause deterioration of the pavement. It was found that the addition of hydrated lime in bituminous mixtures decreases the rate of hardening of the asphalt, thereby, prolonging the life of th...

C. V. Chachas

1971-01-01

245

Method and equipment for induction surface hardening of the leading edges of turbine blades  

Microsoft Academic Search

Methodology and equipment for hardening the leading edges of blades for large nuclear reactor steam turbines was investigated using blades made of 15Kh11MF hardened and tempered steel. A machine was designed and built for hardening the blade leading edges with a vacuum-tube oscillator and 66,000 Hz frequency. The electrical parameters of the induction heating were recorded. Hardening of the actual

T. M. Sorokina; V. V. Dymchenko

1988-01-01

246

Characterization of the hydrogen induced cold cracking susceptibility at simulated weld zones in HSLA-100 steel  

SciTech Connect

The relative susceptibilities to hydrogen induced cold cracking were evaluated for HY-100, a steel presently in service in naval applications and for HSLA-100. The martensitic microstructure of the HY-100 undergoes wide variations in the heat affected zone during welding which strongly influence the resistance of that alloy to cold cracking. The HSLA-100, a low carbon, precipitation hardened steel with similar strength and toughness to that of the HY-100, possesses a significantly lower degree of hardenability which results in minimal microstructural variations in the heat affected zone under the same simulated welding conditions. The mechanical properties of the base metal and the heat affected zone created during a simulated, single welding pass were characterized by the slow strain rate technique for both steels in an inert environment and in artificial seawater under free corrosion and controlled hydrogen fugacities. The electrochemical behaviors of both steels were also evaluated in artificial seawater.

Stoudt, M.R.; Ricker, R.E.

1994-01-01

247

Analysis of the Work-Hardening Process in Spheroidized Steels.  

National Technical Information Service (NTIS)

An elementary model for the work-hardening process in duplex-structures steels (ferrite - spheroidite) is proposed and tested on low, medium and high carbon content, which seems to give good results concerning the influence of the volume fraction and part...

J. L. Pacheco

1981-01-01

248

Soft error hardening for logic-level designs  

Microsoft Academic Search

Vulnerability of combinational logic to soft errors exponentially increases with technology scaling. Reducing soft error susceptibility of logic gates comes with extra area, delay, and power consumption overhead that needs to be balanced in the entire circuit. In this paper, we present efficient soft error hardening techniques based on selective gate resizing to maximize soft error suppression for the entire

Hossein Asadi; Mehdi Baradaran Tahoori

2006-01-01

249

Hardening soft accounting information: Games for planning organizational change  

Microsoft Academic Search

This study provides theory and field evidence on the social process of hardening soft accounting information to make it persuasive for planning organizational change. Accounting information intended to support organizational change is often soft, that is, there is lack of interpersonal agreement about its quality. For example, employees can lack agreement about the quality of accounting information (e.g., activity-based costing)

Casey Rowe; Michael D. Shields; Jacob G. Birnberg

2012-01-01

250

Microstructure of precipitation hardened cobalt rare earth permanent magnets  

Microsoft Academic Search

A transmission electron microscope study of several precipitation hardened cobalt rare earth magnets has been undertaken. The magnets were in peak aged condition and varied in the chemical composition. The studies reveal a fine cellular microstructure. The shape and size of cells depend on the heat treatment and alloying elements. The cell interiors consist of at least two plate-shaped 17:2

J. Fidler; P. Skalicky

1982-01-01

251

Mechanisms of Creep in a Precipitation Hardened Alloy  

Microsoft Academic Search

The binary alloy 97% copper-3% silver was selected as the most ideal alloy for research on the creep process in a precipitation hardened alloy. A heat treatment was divised which gave a slightly overaged Widmanstatten structure of high internal hardness and maximum stability. Wires of the alloy were subjected to deformation over a range of constant stresses at temperatures from

G C E Olds

1954-01-01

252

BUSFET - A Novel Radiation-Hardened SOI Transistor  

SciTech Connect

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

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

1999-02-04

253

RTM of Italy applies power lasers to welding, hardening  

Microsoft Academic Search

The Institute for Mechanical Technology Research and Automation (RTM) has five power lasers, including one with a 15-kW output all lasers are used for process development like, sheet metal welding and spot hardening feasibility tests of mechanical part machining and surface treatment are described.

A. Larane

1985-01-01

254

Overcoming scaling concerns in a radiation-hardening CMOS technology  

SciTech Connect

Scaling efforts to develop an advanced radiation-hardened CMOS process to support a 4M SRAM are described. Issues encountered during scaling of transistor, isolation, and resistor elements are discussed, as well as the solutions used to overcome these issues. Transistor data, total dose radiation results, and the performance of novel resistors for prevention of single event upsets (SEU) are presented.

Maimon, J.; Haddad, N.

1999-12-01

255

Study on boring hardened materials dryly by ultrasonic vibration cutter  

Microsoft Academic Search

It has been one of the difficulties that high-precision hole on hardened materials is machined. The supersonic vibration boring acoustic system in the lathe in which supersonic wave energy is applied on tool is introduced to create pulse power on the cutting process. The separation vibration cutting is achieved by the pulse force. The comparative tests on boring accuracy and

Jiangzhong Zhang; Heng Zhang; Yue Zhang

2010-01-01

256

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

Microsoft Academic Search

The problem of ensuring radar survivability in a HEMP (high-altitude electromagnetic pulse) environment is examined with particular reference to experimental results obtained for the relocatable TRS 22XX radar. The approach used here is global hardening, whereby the whole system except the antenna is enclosed in a Faraday cage. Every penetration of the radar station is protected, the energy input is

G. J. Deville

1987-01-01

257

Engineering design guidelines for electromagnetic pulse hardening of naval equipment  

Microsoft Academic Search

This document is intended to be used by engineers who design and manufacture shipboard equipment. It is complete in the sense that both the EMP hazard and the means of mitigating the hazard (hardening) are presented. The hazard is described, which not only discusses EMP generation in a general sense, but it also presents specific threat levels for EMP fields

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

1981-01-01

258

Strain hardening of titanium: role of deformation twinning  

Microsoft Academic Search

The purpose of this study is to investigate the role of deformation twinning in the strain-hardening behavior of high purity, polycrystalline ?-titanium in a number of different deformation modes. Constant strain rate tests were conducted on this material in simple compression, plane-strain compression and simple shear, and the true stress (?)-true strain (?) responses were documented. From the measured data,

Ayman A. Salem; Surya R. Kalidindi; Roger D. Doherty

2003-01-01

259

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

260

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

261

Modelling of work hardening and stress saturation in FCC metals  

Microsoft Academic Search

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

Erik Nes

1997-01-01

262

Radiation Hardening in Magnox Pressure-Vessel Steels  

Microsoft Academic Search

The ferritic steels used for reactor pressure vessels undergo a marked transition from ductile to brittle fracture behaviour over a relatively narrow temperature range. For most unirradiated mild steels the ductile to brittle transition temperature (d.b.t.t.) is between -50 degrees and 20 degrees C. The process of irradiation hardening, through the formation of clusters of intersitial or vacancy defects, increases

S. B. Fisher; J. E. Harbottle; N. Aldridge

1985-01-01

263

Link Seen Between Hardening of Arteries, Alzheimer's Plaques  

MedlinePLUS

... enable JavaScript. Link Seen Between Hardening of Arteries, Alzheimer's Plaques Study of patients in their 80s looked ... Preidt Wednesday, October 16, 2013 Related MedlinePlus Pages Alzheimer's Disease Atherosclerosis Seniors' Health WEDNESDAY, Oct. 16 (HealthDay ...

264

Stress Corrosion Cracking Evaluation of Martensitic Precipitation Hardening Stainless Steels.  

National Technical Information Service (NTIS)

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...

T. S. Humphries E. E. Nelson

1980-01-01

265

A thermo-mechanical force model for machining hardened steel  

Microsoft Academic Search

The machining 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. ^ In this thesis, an experimental investigation is presented regarding the

Charles Edward Becze

2003-01-01

266

Radiation Effects and Hardening Techniques for Spacecraft Microelectronics  

Microsoft Academic Search

The natural radiation from the Van Allen belts, solar flares, and cosmic rays found outside of the protection of the earth's atmosphere can produce deleterious effects on microelectronics used in space systems. Historically civil space agencies and the commercial satellite industry have been able to utilize components produced in special radiation hardened fabrication process foundries that were developed during the

J. W. Gambles; G. K. Maki

2002-01-01

267

Experimental study of self-compacted concrete in hardened state  

Microsoft Academic Search

The main aim of this work is to investigate the hardened behaviour of Self-Compacting Concrete (SCC). Self compacting Concrete is a special concrete that can flow in its gravity and fill in the formwork alone to its self-weight, passing through the bars and congested sections without the need of any internal or external vibration, while maintaining adequate homogeneity. SCC avoids

Carlos Jose Parra Costa

2006-01-01

268

Shape deformation of a piston ring groove by laser surface hardening  

Microsoft Academic Search

With laser beam heating it is possible to obtain a precisely controlled hardening area, in which the process parameters and material properties are important for the hardened area and deformed surface shape. In this study, the transient heat flow, thermal stress and deformed shape during laser surface hardening of the piston ring groove of a ship's engine were analysed by

K.-K. Yoon; W.-B. Kim; S.-J. Na

1996-01-01

269

Surface hardening of AISI 4340 steel by machining: a preliminary investigation  

Microsoft Academic Search

An attempt has been made to investigate feasibility of applying machining, a material removal process, to surface harden steel parts. The idea is to utilize transient thermomechanical loading induced during machining to purposely generate a hardened layer while simultaneously removing excess materials. This approach, if capable, will be a cost-effective alternative to conventional surface hardening, giving possible benefits such as

Y. Kevin Chou

2002-01-01

270

Towards an Aspect Oriented Approach for the Security Hardening of Code  

Microsoft Academic Search

In this paper, we present an approach revolving around aspect-oriented software development (AOSD) for the systematic security hardening of source code. It provides an abstraction over the actions required to improve the security of the program. Security architects can specify high level security hardening plans that leverages a priori defined security hardening patterns. These patterns describe the steps and actions

Azzam Mourad; Marc-andre Laverdiere; Mourad Debbabi

2007-01-01

271

An aspect-oriented approach for the systematic security hardening of code  

Microsoft Academic Search

In this paper, we present an aspect-oriented approach for the systematic security hardening of source code. It aims at allowing developers to perform software security hardening by providing an abstraction over the actions required to improve the security of the program. This is done by giving them the capabilities to specify high-level security hardening plans that leverage a priori defined

Azzam Mourad; Marc-andré Laverdière; Mourad Debbabi

2008-01-01

272

Mitochondria in the Cold  

Microsoft Academic Search

Development of hibernation strategies for cold preservation of human organs represents a far-reaching goal in transplantation surgery. Short cold storage times of <6 h tolerated by the human heart remain a major clinical problem. Mitochondrial cold storage-reperfusion injury is becoming recognized as a limiting factor in preservation of organs from non-hibernating mammals. Damaged mitochondria lead to cellular injury by reduction

273

Elucidation of real-time hardening mechanisms of two novel high-strength calcium phosphate bone cements.  

PubMed

Despite the numerous literature data available in the field of calcium phosphate bone cements, the mechanism and kinetics of their hardening, both of which are of great importance for cements application, in most cases, is unknown. In this work, the mechanism and kinetics of hardening of two novel high-strength calcium phosphate bone cements were studied using the energy dispersive X-ray diffraction technique, which allows rapid collection of the patterns. The phase transformations occurring on the setting and hardening processes were monitored in situ. Containing minimal quantity of components, whose mixing leads to the formation of cements with pH close to neutral, the cements under study are simple in handling. The main component of both formulations is tetracalcium phosphate. In both cements, the effect of the addition of high- and low-molecular weight chitosan on phase development and kinetics was investigated in detail. One of the cements has the compressive strength of about 70 MPa, whereas the strength of the other, containing Ca(3)Al(2)O(6), is much higher, about 100 MPa. This latter cement could be regarded as an alternative to the common low-strength bioresorbable brushite cements. PMID:20024971

Smirnov, Valery V; Rau, Julietta V; Generosi, Amanda; Albertini, Valerio Rossi; Ferro, Daniela; Barinov, Sergey M

2010-04-01

274

Cold tolerance in cypress ( Cupressus sempervirens L.): a physiological and molecular study  

Microsoft Academic Search

Twenty cypress accessions were tested for freezing tolerance. After freezing to ?15°C, differences among cypress accessions\\u000a were tested by measuring electrolyte leakage and chlorophyll fluorescence. Based on these data, cypress accessions showing\\u000a contrasting freezing tolerance were subjected to transcript profiling of candidate genes upon the development of cold hardening,\\u000a with the ultimate goal of providing a scientific basis for selecting\\/breeding

Paolo Baldi; Luca Pedron; Ari M. Hietala; Nicola La Porta

2011-01-01

275

Reducing pressure on the rolls and tension in the asymmetric cold-rolling of strip  

Microsoft Academic Search

Relations are presented to determine the rolling pressure and forward tension on strip during its asymmetric cold rolling.\\u000a The relations account for the reduction and strain-hardening of the strip, unit frictional forces, the difference between\\u000a the peripheral velocities of the work rolls, and the tension on the ends of the strip. Lowering the pressure of the strip\\u000a metal on the

E. A. Maksimov

2011-01-01

276

The Long Day Leaf As A Source of Cold Hardiness Inhibitors  

PubMed Central

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

Mac Irving, R.; Lanphear, F. O.

1967-01-01

277

Processing of Fe6.5wt.%Si alloy foils by cold rolling  

Microsoft Academic Search

Thin foils of 50 ?m in thickness of Fe-6.5wt.%Si alloy were obtained by conventional hot-cold rolling method. The rolling\\u000a texture and basic mechanical properties of the foils were examined. The foils were heavily work-hardened and exhibited high\\u000a tensile fracture strength with some extent of plastic elongations. Their bending ductility was more remarkable.

Yong-feng Liang; Jun-pin Lin; Feng Ye; Yan-li Wang; Lai-qi Zhang; Guo-liang Chen

2009-01-01

278

Modified Steels for Cold-Forming U-Bolts Used In Leaf Springs Systems  

Microsoft Academic Search

In this work, a low alloy steel and a fabrication process were developed to produce U-Bolts for commercial vehicles. Thus, initially five types of no-heat treated steel were developed with different additions of chrome, nickel, and silicon to produce strain hardening effect during cold-forming processing of the U-Bolts, assuring the required mechanical properties. The new materials exhibited a fine perlite

J. M. Ventura; D. B. V. Castro; C. O. F. T. Ruckert; O. Maluf; W. W. B. Bose Filho; D. Spinelli

2009-01-01

279

Modified Steels for Cold-Forming U-Bolts Used In Leaf Springs Systems  

Microsoft Academic Search

In this work, a low alloy steel and a fabrication process were developed to produce U-Bolts for commercial vehicles. Thus,\\u000a initially five types of no-heat treated steel were developed with different additions of chrome, nickel, and silicon to produce\\u000a strain hardening effect during cold-forming processing of the U-Bolts, assuring the required mechanical properties. The new\\u000a materials exhibited a fine perlite

J. M. Ventura; D. B. V. Castro; C. O. F. T. Ruckert; O. Maluf; W. W. B. Bose Filho; D. Spinelli

2009-01-01

280

Analysis of cold rigid-plastic axisymmetric forging problem by radial basis function collocation method  

Microsoft Academic Search

In the present work, an axi-symmetric cold forging problem is analyzed using radial basis function collocation method. The\\u000a material is assumed to be rigid-plastic strain hardening. At each increment of the punch displacement, the problem is solved\\u000a using an Eulerian control volume approach. The mixed pressure-velocity formulation is adopted, in which the hydrostatic stress\\u000a and velocities are approximated by linear

P. Mahadevan; P. S. Robi

2007-01-01

281

Occupational respiratory and skin sensitization caused by polyfunctional aziridine hardener.  

PubMed

Polyfunctional aziridine (PFA) is increasingly used as a water-based crosslinker in two-component paints, paint primers, lacquers, topcoats and other protective coatings. The crosslinker is made by reacting multifunctional acrylic monomer with a highly reactive aziridine compound. Respiratory allergy or hypersensitivity from PFA has not been reported previously. During 1978-1991 we came across nine cases with hypersensitivity from PFA: two had allergic contact dermatitis (ACD), four had occupational asthma and three had both of them. Five of the patients were parquet layers, two were fibreboard painters, one was a spray painter and one was a salesman of PFA products. ACD was diagnosed by positive allergic patch test reactions with PFA in a dilution series in petrolatum: 0.32%-0.5% gave a 2(+)-3+ allergic reaction in the five cases with ACD but 0.1% gave only a weak reaction in one case, whereas the methacrylate patch test series was negative. The diagnosis of seven cases of occupational asthma due to PFA hardener was based on symptoms related to exposure to PFA hardener at work, and on positive provocation tests with PFA hardener. One had an immediate type reaction, one a had a dual reaction, and the others had late reactions. The positive reactions with the PFA hardener and the negative reactions with the acrylate compounds indicate that PFA caused ACD which is different from the previous reports in which acrylates present as impurities in the PFA hardener caused the sensitization.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7553246

Kanerva, L; Keskinen, H; Autio, P; Estlander, T; Tuppurainen, M; Jolanki, R

1995-05-01

282

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

SciTech Connect

We present measurements of J/{psi} yields in d+Au collisions at {radical}s{sub NN} = 200 GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/{psi} rapidity (-2.2 < 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. In order to remove model dependent systematic uncertainties we also compare the data to a simple geometric model. The forward rapidity 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.; PHENIX Collaboration

2011-09-30

283

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

SciTech Connect

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

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

2011-09-30

284

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

SciTech Connect

We present measurements of J/{psi} yields in d+Au collisions at {radical}s{sub NN} = 200 GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/{psi} rapidity (-2.2 < 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. In order to remove model dependent systematic uncertainties we also compare the data to a simple geometric model. The forward rapidity 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. [University of Colorado, Boulder; Awes, Terry C [ORNL; Cianciolo, Vince [ORNL; Efremenko, Yuri [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Enokizono, Akitomo [Oak Ridge National Laboratory (ORNL); Read Jr, Kenneth F [ORNL; Silvermyr, David O [ORNL; Sorensen, Soren P [University of Tennessee, Knoxville (UTK); Stankus, Paul W [ORNL; PHENIX, Collaboration [The

2011-01-01

285

Cold fusion: Alchemist's dream  

NASA Astrophysics Data System (ADS)

In this report the following topics relating to cold fusion are discussed: muon catalyzed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalyzed cold fusion; vibrational mechanisms in excited states of D2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D2 fusion at low energies; fusion of deuterons into He-4; secondary D+T fusion within the hydrogenated metal lattice; helium-3 to helium-4 ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of helium-3/helium-4.

Clayton, E. D.

1989-09-01

286

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

287

The cold dependent accumulation of COR TMC-AP3 in cereals with contrasting, frost tolerance is regulated by different mRNA expression and protein turnover  

Microsoft Academic Search

The accumulation of specific cold-regulated (COR) proteins is a component of the hardening process and different amount of COR proteins has been related to different degrees of cold tolerance. A number of different mechanisms controls the accumulation of the COR proteins in the plant cells. In this work we describe the mechanisms controlling the accumulation of the COR protein TMC-AP3,

Anna Maria Mastrangelo; Paolo Baldi; Caterina Marè; Valeria Terzi; Gabor Galiba; Luigi Cattivelli; Natale Di Fonzo

2000-01-01

288

Contact corrosion fatigue of medium-carbon steel subjected to various types of surface hardening  

SciTech Connect

In the present work, the authors studied the effects of various methods of surface hardening and relevant structural states of 45 medium-carbon structural steel on its efficiency under the indicated conditions. The authors studied the following types of surface hardening: rolling, frictional hardening, annealing by high-frequency currents, frictional hardening followed by rolling, and high frequency annealing followed by rolling. Based on the data obtained, it was concluded that the most efficient method for increasing the endurance of the steel under investigation is frictional hardening subjected beforehand to annealing followed by medium tempering.

Chaikovs`kyi, B.P.; Yatsyuk, R.A.; Lysyi, V.A.; Vas`kiv, I.P.

1995-05-01

289

Contact allergy to trimethylolpropane triacrylate (TMPTA) in an aziridine plastic hardener.  

PubMed

4 workers developed hand and face dermatitis when exposed to a floor top coat. This contained a polyurethane and a polyfunctional aziridine hardener and additives. The aziridine hardener was made by reacting propyleneimine with a polyfunctional acrylate, trimethylolpropane triacrylate (TMPTA). All 4 reacted to the hardener and to TMPTA, which is present in excess. 2 of them also reacted to pentaerythritol triacrylate (PETA), which can be used in the production of aziridine hardeners. TMPTA and PETA cross-react, and are known sensitizers in UV-hardening acrylates. The present finding shows that well-known sensitizers can be found in hidden sources when used in a quite different chemical process. PMID:6221863

Dahlquist, I; Fregert, S; Trulson, L

1983-03-01

290

Effect of cold compression on precipitation and conductivity of an Al-Li-Cu alloy.  

PubMed

Transmission electron microscopy has been used to investigate the effect of increasing the degree of deformation applied by cold compression on the ageing kinetics and electrical conductivity response of an Al-Li-Cu alloy containing Mg and Ag. When cold compressed greater than 3%, the increased dislocation density accelerates the widespread precipitation of the T(1) phase resulting in an enhanced age hardening response. The lengthening rate of T(1) precipitates is also reduced in this cold compressed condition owing to the reduced local solute supersaturation, a result of the widespread precipitation of T(1) plates. Cold compression by less than 3% does not increase the age hardening response, and the precipitation of GP zones/theta'' appears to be suppressed. Precipitation of the T(1) phase is also not significantly enhanced compared with that of the more than 3% cold compressed conditions. The anomalous decrease in electrical conductivity is associated with the nucleation and growth of the T(1) phase. Strain fields around T(1) precipitates combined with the increased volume fraction of T(1) are thought to be the cause of the anomalous conductivity behaviour. PMID:19094036

Khan, A K; Robinson, J S

2008-12-01

291

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

Microsoft Academic Search

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

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

2010-01-01

292

Progress with cold antihydrogen  

Microsoft Academic Search

The creation of cold antihydrogen by the ATHENA and ATRAP collaborations, working at CERN’s unique Antiproton Decelerator (AD) facility, has ushered in a new era in atomic physics. This contribution will briefly review recent results from the ATHENA experiment. These include discussions of antiproton slowing down in a cold positron gas during antihydrogen formation, information derived on the dependence of

M. Amoretti; C. Amsler; G. Bonomi; P. D. Bowe; C. Canali; C. Carraro; C. L. Cesar; M. Charlton; M. Doser; A. Fontana; M. C. Fujiwara; R. Funakoshi; P. Genova; J. S. Hangst; R. S. Hayano; I. Johnson; L. V. Jørgensen; A. Kellerbauer; V. Lagomarsino; R. Landua; E. Lodi Rizzini; M. Macrí; N. Madsen; G. Manuzio; D. Mitchard; P. Montagna; H. Pruys; C. Regenfus; A. Rotondi; G. Testera; A. Variola; L. Venturelli; D. P. van der Werf; Y. Yamazaki; N. Zurlo

2006-01-01

293

Chilling Out with Colds  

MedlinePLUS

... in these droplets can spread a cold from one person to another. You also can catch a cold ... and watery eyes coughing feeling tired and not hungry congestion (when your nose is stuffy and it's hard to breathe) Helping Kids Feel Better Here are some feel-better ...

294

Exercise in the cold  

Microsoft Academic Search

Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11°C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient

Myra Nimmo

2004-01-01

295

Cold waves in Serbia  

NASA Astrophysics Data System (ADS)

Climate extreme indices allow the assessment of changes in extreme climate events. The cold Spell Duration Indice (CSDI), from which the duration and severity of the cold waves are estimated, was applied to the seasonal series of the daily minimum temperatures at 15 meteorological stations in Serbia during the period 1949 to 2012. An analysis of the daily minimum temperatures during the winter season revealed that the longest (up to 20-22 days) and most severe cold waves were recorded in 1954, 1956, 1963 and 1983. In the transient seasons, the cooling episodes were observed in 1983 and 1988 (autumn season) and in 1987 (spring season) followed with a great reduction in duration and severity of cold waves. During the summer season, only in 1962, the longest (from 6 to 8 days) and most intense cold wave was registered almost over the whole territory of Serbia.

Unkasevic, Miroslava; Tosic, Ivana

2013-04-01

296

Cold Acclimation in Arabidopsis thaliana1  

PubMed Central

The abilities of two races of Arabidopsis thaliana L. (Heyn), Landsberg erecta and Columbia, to cold harden were examined. Landsberg, grown at 22 to 24°C, increased in freezing tolerance from an initial 50% lethal temperature (LT50) of about ?3°C to an LT50 of about ?6°C after 24 hours at 4°C; LT50 values of ?8 to ?10°C were achieved after 8 to 9 days at 4°C. Similar increases in freezing tolerance were obtained with Columbia. In vitro translation of poly(A+) RNA isolated from control and cold-treated Columbia showed that low temperature induced changes in the population of translatable mRNAs. An mRNA encoding a polypeptide of about 160 kilodaltons (isoelectric point about 4.5) increased markedly after 12 to 24 h at 4°C, as did mRNAs encoding four polypeptides of about 47 kilodaltons (isoelectric points ranging from 5-5.5). Incubation of Columbia callus tissue at 4°C also resulted in increased levels of the mRNAs encoding the 160 kilodalton polypeptide and at least two of the 47 kilodalton polypeptides. In vivo labeling experiments using Columbia plants and callus tissue indicated that the 160 kilodalton polypeptide was synthesized in the cold and suggested that at least two of the 47 kilodalton polypeptides were produced. Other differences in polypeptide composition were also observed in the in vivo labeling experiments, some of which may be the result of posttranslational modifications of the 160 and 47 kilodalton polypeptides. Images Fig. 2 Fig. 3 Fig. 4

Gilmour, Sarah J.; Hajela, Ravindra K.; Thomashow, Michael F.

1988-01-01

297

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

298

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

2013-07-01

299

Contribuicao ao estudo de recuperacao e recristalizacao do zircaloy-4 laminado a frio. (Contribution to study on recovery and recrystallization of cold rolling zircaloy-4).  

National Technical Information Service (NTIS)

Recovery and recrystallization of work-hardened (40-60% - Cold rolling) Zircaloy-4 were studied between 200 and 600(sup 0) C with times varying from 15 to 240 minutes, from electrical resistance and hardness measurements. Activation energy calculation for...

A. I. C. Persiano

1977-01-01

300

The design of radiation-hardened ICs for space  

SciTech Connect

The approaches to designing radiation-hardened integrated circuits for space applications are reviewed in this paper. Several technologies are covered, including bulk and epi CMOS, CMOS/SOL-SOS, CML,ECL, analog bipolar (JI, single-poly DI, and SOI) and GaAsE/D Heterojunction MESFET. Sections of the paper cover the direct effects of space radiation on microelectronic materials and devices, how these effects are evidenced in circuit and device design parameter variations, the particular effects of most significance to each functional class of circuit, specific techniques for hardening high-speed circuits, design examples for integrated systems, including operational amplifiers and A/D converters, and the computer simulation of radiation effects on microelectronic ICs.

Kerns, S.E.; Shafer, B.D.

1988-11-01

301

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

302

CMOS inverter design-hardened to the total dose effect  

SciTech Connect

This paper reports and discusses the experimental behavior of two inverter structures Rad-Hardened by Design to {sup 60}Co irradiation. The authors use the results on a set of basic circuits and transistors exposed to the same total doses as these structures to establish the effective formation conditions of the parasitic channel. Then this leakage evolution is related to the gate voltage history under irradiation. Finally, they take advantage of this intrinsic degradation property to propose a new Design Rad Hardened (DRH) cell. This structure considerably limits the Low Noise Margin degradation, helps to maintain the logic functionality with a High Output level and improves both the rad-tolerance and the static power consumption.

Roche, F.M.; Salager, L. [Universite Montpellier II/CNRS (France). Lab. d`Informatique de Robotique et de Microelectronique

1996-12-01

303

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

304

Magnetic hardening in iron-neodymium-boron permanent magnets  

Microsoft Academic Search

The origin of magnetic hardening has been examined in Fe-Nd-B magnets by correlating the magnetic properties with the microstructure and magnetic domain structure observed with electron microscopy. Hysteresis loops and susceptibility studies show a magnetic anomaly at around 140 K. Microstructure studies reveal the presence of at least four phases with compositions Fe14R2B, Fe4NdB4, a high-Nd-content phase, and ?-Fe. Initial

G. C. Hadjipanayis; K. R. Lawless; R. C. Dickerson

1985-01-01

305

Magnetic hardening in iron-neodymium-boron permanent magnets  

Microsoft Academic Search

The origin of magnetic hardening has been examined in Fe-Nd-B magnets by correlating the magnetic properties with the microstructure and magnetic domain structure observed with electron microscopy. Hysteresis loops and susceptibility studies show a magnetic anomaly at around 140 K. Microstructure studies reveal the presence of at least four phases with compositions Fe14R2B, Fe4NdB4, a high-Nd-content phase, and alpha-Fe. Initial

G. C. Hadjipanayis; K. R. Lawless; R. C. Dickerson

1985-01-01

306

Laser hardening of VT6 and VT23 titanium alloys  

NASA Astrophysics Data System (ADS)

The characteristics of the surface hardening of VT6 and VT23 titanium alloys during laser heat treatment and laser boriding are investigated theoretically and experimentally. A model is proposed which describes the kinetics of the alpha+beta - beta transformation and beta phase homogenization under the high heating and cooling rates typical of laser treatments. The possibility of controlling the structure of the fusion zone by varying the parameters of laser boriding is demonstrated.

Gordienko, A. I.; Ivashko, V. V.; Bushik, S. V.

1989-06-01

307

Sinter-hardening process applicable to stainless steels  

Microsoft Academic Search

Purpose: of this paper was to describe sintered duplex stainless steels manufactured in sinter-hardening process and its usability in field of stainless steels. Design\\/methodology\\/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, ferritic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies apart from the

L. A. Dobrza?ski a; Z. Brytan; M. Rosso

308

A NEW RETARDING AGENT OF BUILDING GYPSUM HARDENING  

Microsoft Academic Search

In order to inhibit the process of setting and hardening of building gypsum, retarding agents are used. They:i. decrease the solubility of gypsum semihydrate (e.g. ammonia)ii. form compounds of lower solubility on the surface of gypsum grains (sodium and potassium phosphates, tetraborate, boric acid)iii. are absorbed on gypsum grain surface and inhibit the formation of crystal nuclei (sulphite alcohol ferment,

A. Kazragis; G. Mar?iukaitis; G. Jurk?nas

1996-01-01

309

A multi MRad hardened 8 bit\\/20 MHz flash ADC  

Microsoft Academic Search

An 8-bit, 20-MHz flash ADC (analog-to-digital converter) using a radiation-hardened SOI (silicon on insulator) process is presented. The circuit is capable of operating at up to 20 MHz, even after a total dose exposure of 100 Mrad (SiO2) (10 keV X-rays). Simultaneous use of a rad-hard technology and optimized design in order to withstand the effects of a total dose

F. Baille; G. Borel; B. Commere; F. Roy; C. Delmas; C. Terrier

1992-01-01

310

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

311

Strain hardening of titanium: Role of deformation twinning  

Microsoft Academic Search

The quasi-static mechanical response of high purity, polycrystalline alpha-titanium is investigated in terms of the underlying deformation mechanisms that govern its macroscopic behavior at room temperature. Constant strain rate tests were conducted on this material in simple compression, plane-strain compression and simple shear, and the true stress (sigma)-true strain (epsilon) responses were documented. From the measured data, the strain hardening

Ayman A. Hussien Salem

2002-01-01

312

Hardening of commercial CMOS PROMs with polysilicon fusible links  

NASA Astrophysics Data System (ADS)

The method by which a commercial 4K CMOS PROM with polysilicon fuses was hardened and the feasibility of applying this method to a 16K PROM are presented. A description of the process and the necessary minor modifications to the original layout are given. The PROM circuit and discrete device characteristics over radiation to 1000K rad-Si are summarized. The dose rate sensitivity of the 4K PROMs is also presented.

Newman, W. H.; Rauchfuss, J. E.

1985-12-01

313

Optically-triggered hardened thyristors for firing set circuits  

SciTech Connect

Silicon thyristors, directly triggered by light, are used to switch pulsed currents in firing set circuits. They are hardened to transient ionizing radiation by the addition of a reverse-biased compensating photodiode connected to the gate of the thyristor. Tests of these compensated devices show radiation-induced switching is completely inhibited in excess of 1.4 {times} 10{sup 9} rad (Si)/sec. 2 refs., 5 figs.

Carson, R.F.; Knauss, G.L.

1990-01-01

314

Study on the hardening mechanism of cement asphalt binder  

Microsoft Academic Search

The hydration and hardening mechanism of cement asphalt binder (CAB) was studied. The early hydration process, hydration products\\u000a and paste microstructure of CAB made by Portland cement and anionic asphalt emulsion were investigated by calorimetry, X-ray\\u000a diffraction, and environmental scanning electron microscopy. The early hydration process of CAB can be characterized as 5\\u000a stages similar to those of Portland cement.

JinBo Yang; PeiYu Yan; XiangMing Kong; Xiang Li

2010-01-01

315

Thermodynamic calculation for precipitation hardening steels and titanium aluminides  

Microsoft Academic Search

Thermodynamic calculation using Thermo-Calc was carried out to quantify the phase fraction and element partition in precipitation hardening steels and ?-TiAl based alloys. Calculations show that the precipitates formed in Fe–Ni–Al–Mo systems and PH13-8 stainless steel are NiAl phases, in accordance with atom probe microanalysis. Calculations of the phase constitution and element distribution in several titanium aluminides show again a

Z Guo; W Sha

2002-01-01

316

Sequential circuit design for radiation hardened multiple voltage integrated circuits  

SciTech Connect

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

317

Implicit strain-hardening formulation for creep analysis  

Microsoft Academic Search

A variable stiffness method for creep analysis is presented that utilizes a strain-hardening theory of creep and an implicit time-marching scheme. The formulation makes use of the change in stress and accumulated creep strain during a time interval to determine the corresponding creep strain increment. The method is well suited for use in formulations of elastic-plastic-creep and large displacement, small

B. R. Bass; W. G. Johnson; S. V. McGrath

1979-01-01

318

Hardening treatment of machine parts with CO2 power lasers  

Microsoft Academic Search

Two technological laser facilities were built at the All-Union Scientific Research Institute of Electrothermal Equipment for hardening machine parts using 1.2 and 2.5 kW CO2 lasers. Both lasers are continuous wave devices with self sustained gas discharge between flat anode and tubular cathode. Each facility includes a Fabry-Perot resonator, a beam transporting and focusing mechanism, a laser power measuring instrument

A. S. Borodachev; M. B. Gutman; G. A. Kuznetsov; L. A. Medvedovskaya; G. K. Rubin

1986-01-01

319

Surface hardening of steel with a low-power laser  

NASA Astrophysics Data System (ADS)

A locally developed 200 W CO2 laser with multi-mode output was used to study the surface hardening of different steels. Maximum hardness was achieved in the region where the microstructure was transformed to martensite. The microhardness was found to increase with carbon content. In a new experiment, AISI 1045 steel specimen was first annealed and then treated with laser. The microhardness of annealed samples was found to be higher than the untreated samples. Preliminary results are presented.

Hussain, A.; Akhtar, R.; Shahdin, S.; Atta, M. A.

2001-04-01

320

Study on boring hardened materials dryly by ultrasonic vibration cutter  

NASA Astrophysics Data System (ADS)

It has been one of the difficulties that high-precision hole on hardened materials is machined. The supersonic vibration boring acoustic system in the lathe in which supersonic wave energy is applied on tool is introduced to create pulse power on the cutting process. The separation vibration cutting is achieved by the pulse force. The comparative tests on boring accuracy and surface quality are carried. The quality of surface machined by this method is compared to that by grinding. This cutting is the green cutting. The boring process system is stability. Under the condition that the cutting speed is less than or equal to 1/3 the tool vibration speed, the cutting force is pulse force and the Cutting energy is of high concentration in time, space and direction. The pulse energy effects on the cutting unit in less than one ten-thousandth second. Traditional cutting of irregular movement elastic compression are eliminated. The cutting force is greatly reduced. The cutting temperature is at room temperature. The tool life is greatly increased. Shape precision and surface quality is greatly improved. The regulations of the ultrasonic vibration boring dry cutting of hardened material are also summarized. The test results show that the ultrasonic vibration cutting tool boring is of very superior cutting mechanism and is a high-precision deep-hole machining of hardened materials, efficient cutting methods.

Zhang, Jiangzhong; Zhang, Heng; Zhang, Yue

2010-12-01

321

Hardening and welding with high-power diode lasers  

NASA Astrophysics Data System (ADS)

Commercially available high power diode lasers (HPDLs) with output powers of up to 6 kW have been recognized as an interesting tool for industrial applications. In certain fields of application they offer many advantages over Nd:YAG and CO2 lasers because of their low maintenance, compact design and low capital costs. Examples of successful industrial implementation of HPDLs include plastic welding, surface hardening and heat conduction welding of stainless steel and aluminum. The joining of plastics with an HPDL offers the advantages of producing a weld seam with high strength, high consistency and superior appearance. One example is the keyless entry system introduced with the Mercedes E-class where the microelectronic circuits are embedded in a plastic housing. Other applications include instrument panels, cell phones, headlights and tail lights. Applications in the field of surface treatment of metals profit from the HPDL's inherent line-shaped focus and the homogeneous intensity distribution across this focus. An HPDL system is used within the industry to harden rails for coordinate measurement machines. This system contains a customized zoom optic to focus the laser light onto the rails. With the addition of a temperature control, even complex shapes can be hardened with a constant depth and minimum distortion.

Ehlers, Bodo; Herfurth, Hans-Joachim; Heinemann, Stefan

2000-03-01

322

Age hardening in rapidly solidified and hot isostatically pressed beryllium-aluminum-silver alloys  

SciTech Connect

Three different alloys of beryllium, aluminum and silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compositions were, by weight, 50% Be, 47.5% Al, 2.5% Ag, 50% Be, 47% Al, 3% Ag, and 50% Be, 46% Al, 4% Ag. Due to the low solubility of both aluminum and silver in beryllium, the silver was concentrated in the aluminum phase, which appeared to separate from the beryllium in the liquid phase. A fine, continuous composite beryllium-aluminum microstructure was formed, which did not significantly change after hot isostatically pressing at 550 C for one hour at 30,000 psi argon pressure. Samples of HIP material were solution treated at 550 C for one hour, followed by a water quench. Aging temperatures were 150, 175, 200 and 225 C for times ranging from one half hour to 65 hours. Hardness measurements were made using a diamond pyramid indenter with a load of 1 kg. Results indicate that peak hardness was reached in 36--40 hours at 175 C and 12--16 hours at 200 C aging temperature, relatively independent of alloy composition.

Carter, D.H.; McGeorge, A.C.; Jacobson, L.A.; Stanek, P.W.

1995-07-01

323

Environmental hardening of equipment operating in an automated test bed enclosure. Special Isotope Separation Program (SIS)  

SciTech Connect

Lawrence Livermore National Laboratory`s Plutonium Systems Engineering plans to demonstrate a materials handling system in an automated test bed located in the cold test facility, in FY91. The equipment operating in the automated glove box test bed consists of a modified, bridge mounted robot that is electrically driven, robot tooling, a tilt-pour furnace, mechanisms for loading and unloading the furnace, mechanisms for loading and unloading the crucible, and mechanisms for button breakout and can opening. Each of the pieces of equipment mentioned have components such as motors (with or without brushes), bearings, resolvers, encoders, sliding surfaces, cabling, and electrical connectors that must function in the harsh environment of the test bed enclosure, and each of the components described must be hardened to the enclosure environment. The automated test bed is to provide a representation of a weapons-grade plutonium enclosure. Although the decision to operate the enclosure in a nitrogen or argon atmosphere has not been made, this report considers the dry argon atmosphere as the more difficult case. Other environmental requirements on the equipment operating in the test bed enclosure are: Low moisture and low oxygen atmosphere, and some abrasive dust resulting from the process. A surrogate material will provide flow and dusting characteristics of weapons-grade plutonium oxide. Weapons-grade plutonium will not be introduced into the test bed enclosure. However, for future reference, radiation effects on materials are addressed.

Hayward, M.L.

1990-12-01

324

Aluminum nitride precipitation and texture development in batch-annealed bake-hardening steel  

SciTech Connect

A model is presented that describes the development of texture during the production process of bake-hardening steel recrystallized in a batch-annealing furnace. Proper conditions are analyzed to generate a pronounced {gamma}-fiber texture and a pancake microstructure that shows superior deep drawability. The {gamma}-fiber texture is assumed to be caused by the interaction between tertiary precipitating aluminum nitride particles and the recrystallization process during heating in the furnace. Deep drawability is presented in terms of the logarithmic {gamma}- and {alpha}-fiber X-ray intensity ratio. The computer simulation of the coupled aluminum nitride precipitation and recrystallization kinetics is based on an iterative procedure. A comparison between simulation results and available experimental data proves the ability of the model to predict the final deep drawability, taking into account the initial aluminum and nitrogen contents, the time/temperature history during slab reheating, hot rolling and coiling, the degree of cold reduction, and the heating rate during batch annealing.

Kozeschnik, E. [Oak Ridge National Lab., TN (United States)]|[Technical Univ. Graz (Austria). Inst. for Materials Science, Welding and Forming; Pletenev, V.; Zolotorevsky, N. [St. Petersburg State Technical Univ. (Russian Federation). Dept. of Metal Physics; Buchmayr, B. [Technical Univ. Graz (Austria). Inst. for Materials Science, Welding and Forming

1999-06-01

325

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

PubMed

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

Walke, Witold; Przondziono, Joanna

2012-01-01

326

Complexity of the cold acclimation response in Drosophila melanogaster.  

PubMed

Insects can increase their resistance to cold stress when they are exposed to non-lethal conditions prior to the stress; these plastic responses are normally described only in terms of immediate effects on mortality. Here we examine in Drosophila melanogaster the short- and longer-term effects of different conditions on several measures of cold resistance, but particularly chill coma recovery. Short-term exposure to sublethal temperature (cold hardening) did not decrease chill coma recovery times even though it decreased mortality. Exposure to 12 degrees C for 2 days (acclimation) decreased chill coma recovery times for a range of stressful temperatures when flies were cultured at 25 degrees C, but did not usually affect recovery times when flies were cultured at 19 degrees C. In contrast, 2-day exposure to 12 degrees C decreased mortality regardless of rearing temperature. Rearing at 19 degrees C decreased mortality and chill coma recovery time relative to rearing at 25 degrees C. Acclimation increased the eclosion rate of eggs from stressed females, but did not affect development time or size of the offspring. These results indicate that plastic responses to cold in D. melanogaster are complex when resistance is scored in different ways, and that effects can extend across generations. PMID:16257412

Rako, Lea; Hoffmann, Ary A

2005-10-28

327

Light and temperature dependent inhibition of photosynthesis in frost-hardened and un-hardened seedlings of pine  

Microsoft Academic Search

Needles of un-hardened and frost-hardended seedlings of Pinus sylvestris and Pinus contorta were exposed to photoinhibitory photon flux densities at temperatures between 0 and 35°C under laboratory conditions. Photoinhibition of photosynthesis was assayed by measuring oxygen evolution under saturating CO2 in a leaf disc oxygen electrode or by recording of photosystem II fluorescence induction kinetics at 77 K. It was

Gunnar Öquist; Gunilla Malmberg

1989-01-01

328

Febrile/cold agglutinins  

MedlinePLUS

Cold agglutinins; Weil-Felix reaction; Widal's test; Warm agglutinins; Agglutinins ... but may include: Excessive bleeding Fainting or feeling light-headed Hematoma (blood accumulating under the skin) Infection ( ...

329

Exercise in the Cold.  

National Technical Information Service (NTIS)

Humans have developed the technical capability to protect themselves, from a thermoregulation point of view, against almost any terrestrial extreme. With respect to the extreme cold, it is understood that the best technique to ensure survival resides in e...

A. L. Vallerand

1995-01-01

330

Cold Sores (Herpes)  

MedlinePLUS Videos and Cool Tools

... Unfortunately, the cold sore virus usually hides in nerve cells. This makes it impossible for antibodies to totally kill the virus. The virus “sleeps” in the nerve cells. While “asleep,” the virus is called dormant. When ...

331

Cold plasma dispersion surfaces  

Microsoft Academic Search

Following the work of Stringer (1963), this study presents three-dimensional plots of dispersion in a cold anisotropic plasma. The omega(k, theta) surfaces (where k is the wave vector for a fixed angle of propagation) provide a clear picture of the behavior of cold plasma waves as the direction of propagation is varied. The group velocity (dw\\/dk) has a simple geometrical

M. E. Oakes; R. B. Michie; K. H. Tsui; J. E. Copeland

1979-01-01

332

Transmission of colds  

Microsoft Academic Search

Rhinorrhea, nasal congestion, and sore throat herald the beginning of the cold season for both children and adults. Although\\u000a the common cold is a self-limited infection, there are no effective treatments presently available and complications, missed\\u000a time from work and school, and overall discomfort are not insignificant. Understanding how infections are transmitted may\\u000a lead to interventions to reduce rates of

Diane E. Pappas; J. Owen Hendley

333

Exercise in the cold.  

PubMed

Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11 degrees C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient metabolic heat to offset the effects imposed by the cold environment, then temperatures of 11 degrees C can be detrimental to performance. Similarly, when the performance involves dynamic explosive contractions, then a Cold ambient temperature can have a negative influence. Additional factors such as the exercising medium, air or water, and the anthropometric characteristics of the athlete will also make a difference to the strategies that can be adopted to offset any negative impact of a cold environment on performance. To plan for a performance in the cold requires an understanding of the mechanisms underpinning the physiological response. This review attempts to outline these mechanisms and how they can be manipulated to optimize performance. PMID:15768724

Nimmo, Myra

2004-10-01

334

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

335

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

336

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

337

Therapeutic Hypothermia: What's Hot about Cold  

PubMed Central

Reducing body temperature to 33°C in patients who have been resuscitated from cardiac arrest but who remain comatose can ameliorate anoxic encephalopathy and improve recovery. Experimental animal studies have suggested that cooling to 33°C also aids the resuscitative process itself, facilitating the resumption of spontaneous circulation (ROSC). The mechanism of cooling benefit is probably the reduction of metabolic demand of most organs, and reduced production of toxic metabolites and reactive oxygen species. External cooling by application of ice or pads through which cold water circulates is effective but requires up to 8 hours to achieve the target temperature of 33°C. Our goal was to develop a faster method of cooling that could be initiated during cardiopulmonary resuscitation. In anesthetized swine, we induced ventricular fibrillation by passing alternating current down an electrode catheter in the right ventricle. We then ventilated the animals' lungs with liquid perfluorocarbons (PFCs), a technique known as total liquid ventilation (TLV). Perfluorocarbons are oxygen-carrying modules; we pre-oxygenated the PFCs by bubbling 100% O2 through the solution for 2 minutes before use, and pre-cooled the PFCs to ?15°C. The cold oxygenated PFCs reduced pulmonary artery temperature (a surrogate for myocardial temperature) to 33°C in about 6 minutes. Using this technique we achieved ROSC in 8 of 11 (82%) animals given TLV versus 3 of 11 (27%) control animals receiving conventional CPR without PFCs (P < 0.05). We also compared the cold TLV technique with the administration of intravenous iced saline to achieve hypothermia. Both the cold TLV and cold saline techniques produced rapid hypothermia, but we could achieve ROSC in only 2 of 8 (25%) animals given cold saline versus 7 of 8 (88%) given cold TLV. This result is likely due to the rise in right atrial pressure and corresponding reduction in coronary perfusion pressure caused by volume loading with IV saline, in addition to the higher pO2 associated with pre-oxygenated PFCs. Cold TLV is a promising technique for achieving rapid intra-arrest and post-resuscitation hypothermia in patients experiencing cardiac arrest.

Kerber, Richard E.

2011-01-01

338

Evaluation of a patient with cold and cholinergic urticaria.  

PubMed

A-20-year-old male Army paratrooper presented with a history of inducible urticaria associated with exercise as well as cold exposure. Upon evaluation, he not only had a positive ice cube test, but also had a positive mecholyl skin test with numberous satellite lesions and generalized punctate urticaria following exercise challenge. Thus, he appeared to have combined cold and cholinergic urticaria. When mediator release was examined during cold and exercise challenge, histamine release was observed in each instance; a rapid rise and fall of plasma histamine was seen after cold challenge, while a lag phase followed by sustained elevation of plasma histamine was associated with exercise challenge. This represents the fourth reported case of combined cold and cholinergic urticaria and is the first in whom mediator release was assessed. The time-course of histamine release was characteristic of each disorder. PMID:82566

Sigler, R W; Levinson, A I; Evans, R; Horakova, Z; Kaplan, A P

1979-01-01

339

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

Microsoft Academic Search

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

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

2008-01-01

340

Simultaneous plasma nitriding and ageing treatments of precipitation hardenable plastic mould steel  

Microsoft Academic Search

Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr–Ni–Mo–Al age hardenable steel, in the solubilized and solubilized and aged conditions, were

Sandro D. Oliveira; André P. Tschiptschin; Carlos E. Pinedo

2007-01-01

341

Short communication Simultaneous plasma nitriding and ageing treatments of precipitation hardenable plastic mould steel  

Microsoft Academic Search

Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were

Sandro D. Oliveira; Carlos E. Pinedo; Mello Moraes; Rodovia Indio Tibirica; Bairro Raffo

342

Laser transformation hardening of AISI 440C martensitic stainless steel for higher cavitation erosion resistance  

Microsoft Academic Search

Surface hardening of AISI 440C martensitic stainless steel was achieved by laser transformation hardening (LTH) using a high-power CW Nd:YAG laser. A hardened layer of a few 100 ?m thick, composed of martensite, retained austenite and fine carbides was formed. The microstructure and hardness of the laser-treated layer were dependent on the laser processing parameters, with the hardness values reaching

K. H. Lo; F. T. Cheng; H. C. Man

2003-01-01

343

Non-destructive prediction of hardening pericarp disorder in intact mangosteen by near infrared transmittance spectroscopy  

Microsoft Academic Search

A non-destructive technique to predict a hardening pericarp disorder in intact mangosteen is proposed by using near infrared (NIR) transmittance spectroscopy in the wavelength range of 660–960nm. The study found that the spectral features of normal pericarp mangosteen and hardening pericarp mangosteen were different. The averaged spectra and individual spectra of hardening pericarp mangosteen from a calibration set (N=560) were

Sontisuk Teerachaichayut; Anupun Terdwongworakul; Warunee Thanapase; Kazuaki Kiji

2011-01-01

344

Precipitation hardening of a beta-titanium alloy by the alpha-two phase. Technical report  

SciTech Connect

The age hardening of beta titanium alloys by the formation of ordered alpha two precipitates based on Ti3Al has been investigated by transmission electron microscopy and hardness observations. Results of tests based on the alloy Ti 23Nb 11 Al (at. %) show a large precipitation hardening response at temperatures considerably higher than is possible in current beta titanium alloys. TEM identifies the hardening to be caused by the formation of ordered, alpha two precipitates.

Quattrocchi, L.S.; Koss, D.A.; Scarr, G.

1991-09-25

345

Surface hardening of 9KhF steel by heating with a plasma gun  

Microsoft Academic Search

1.The plasma heating process of 9KhF steel provides obtaining of hardened surface cases with a martensitic structure. The depth of the hardened cases with a microhardness of more than 800 H may reach 1 mm.2.The depth of the hardened case changes proportionally to the parameter P\\/(dnP)0.4, where P is the arc power, dn is the diameter of the plasmatron delivery

V. S. Kraposhin; A. V. Bobrov; O. S. Gaponenko

1989-01-01

346

Bulk-hardened magnets based on Y2Co17  

NASA Astrophysics Data System (ADS)

Bulk magnetic hardening of cast Y2Co17-based alloys was systematically studied for different compositions and heat treatments. Additions of Cu and Zr, Hf, or Ti to the Y-Co were found to be essential for developing coercivity. The performance of Y-Co-Cu-Zr magnets can be significantly improved by partial Pr and Fe substitutions for Y and Co, respectively. Anisotropic (Y0.8Pr0.2)11.5Zr2.75Co56.75Fe14Cu15 powders with intrinsic coercivity of 7.8 kOe and energy product of 14.4 MG Oe were obtained after annealing at 900 °C for 15 min and cooling to 200 °C at the rate of 4 °C/min. We also explored the effects of some other rare earths (La, Nd, Gd) and transition metals (Mn, Ni) on the magnetic properties of the Y-Co-Cu-Zr magnets. The phases present and the microstructure were analyzed with x-ray diffraction, thermomagnetic analysis, and transmission electron microscopy. The cellular/lamellar microstructure of the bulk-hardened alloys is similar to that of Sm-Co-Cu-Zr magnets. Among the most noticeable distinctions in the Y-Co-Cu-Zr alloys are a smaller average size of 2:17 cells and a variety of Zr-rich phases, like Zr2Co11 and Zr6Co23. Although the Y2Co17 phase is known to have an ``easy-plane'' anisotropy, the x-ray diffraction experiments with magnetically oriented powders suggest that in the bulk-hardened Y-Co-Cu-Zr and Y-Co-Cu-Fe-Zr magnets the 2:17 phase has uniaxial anisotropy.

Gabay, A. M.; Zhang, Y.; Hadjipanayis, G. C.

2001-07-01

347

Organoapatites: materials for artificial bone. II. Hardening reactions and properties.  

PubMed

This article reports on chemical reactions and the properties they generated in artificial bone materials termed "organoapatites." These materials are synthesized using methodology we reported in the previous article of this series. Two different processes were studied here for the transition from organoapatite particles to implants suitable for the restoration of the skeletal system. One process involved the hardening of powder compacts by beams of blue light derived from a lamp or a laser and the other involved pressure-induced interdiffusion of polymers. In both cases, the hardening reaction involved the formation of a polyion complex between two polyelectrolytes. In the photo-induced reaction an anionic electrolyte polymerizes to form the coulombic network and in the pressure-induced one, pressure forms the complex by interdiffusion of two polyions. Model reactions were studied using various polycations. Based on these results the organoapatite selected for the study was that containing dispersed poly(L-lysine) and sodium acrylate as the anionic monomer. The organomineral particles can be pressed at room temperature into objects of great physical integrity and hydrolytic stability relative to anorganic controls. The remarkable fact about these objects is that intimate molecular dispersion of only 2-3% by weight organic material provides integrity to the mineral network in an aqueous medium and also doubles its tensile strength. This integrity is essentially nonexistent in "anorganic" samples prepared by the same methodology used in organoapatite synthesis. The improvement in properties was most effectively produced by molecular bridges formed by photopolymerization. The photopolymerization leads to the "hardening" of pellets prepared by pressing of organoapatite powders. The reaction was found to be more facile in the microstructure of the organomineral, and it is potentially useful in the surgical application of organoapatites as artificial bone. PMID:8360199

Stupp, S I; Mejicano, G C; Hanson, J A

1993-03-01

348

BUSFET - A Novel Radiation-Hardened SOI Transistor  

SciTech Connect

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 amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, we propose a new partially-depleted SOI transistor structure that we call the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU and dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration and the depth of the source. 3-D simulations show that for a doping concentration of 10{sup 18} cm{sup {minus}3} and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3x10{sup 17} cm{sup {minus}3}, a thicker silicon film (300 nm) must be used.

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

1999-07-20

349

Radiation-Hardened Software for Space Flight Science Applications  

NASA Astrophysics Data System (ADS)

Hardware faults caused by radiation-induced Single Event Effects (SEEs) are a serious issue in space flight, especially affecting scientific missions in earth orbits crossing the poles or the South Atlantic Anomaly. Traditionally, SEEs are treated as a hardware problem, for example mitigated by radiation-hardened processors and shielding. Rad-hardened processors are expensive, exhibit a decade performance gap compared to COTS technology, have a larger form factor and require more power. Shielding is ineffective for high energy particles and increases launch weight. Hardware approaches cannot dynamically adapt protection levels for different radiation scenarios depending on solar activity and flight phase. Future hardware will exacerbate the problem due to higher chip densities and lower power levels. An alternative approach is to use software to mitigate SEEs. This "Radiation Hardened Software" (RHS) approach has two components: (1) RHS library and application design guidelines To increase robustness, we combine SEE countermeasures in three areas: prevention and detection; recovery; and reconfiguration. Prevention and detection includes an application- and heap-aware memory scanner, and dynamically adapted software Error Correction Codes to handle cache and multi-bit errors. Recovery mechanisms include exception firewalls and transaction-based software design patterns, to minimize data loss. Reconfiguration includes a heap manager to avoid damaged memory areas. (2) Software-based SEE Simulation Probabilistic effects require extensive simulation, with test environments that do not require original flight hardware and can simulate various SEE profiles. We use processor emulation software, interfaced to a debugger, to analyze SEE propagation and optimize RHS mechanisms. The simulator runs unmodified binary flight code, enables injecting randomized transient and permanent memory errors, providing execution traces and precise failure reproduction. The goal of RHS is to verify that effective SEE software countermeasures are implementable at reasonable runtime costs, enabling use of more COTS hardware with significant performance gains for science applications.

Mehlitz, P. C.; Penix, J. J.; Markosian, L. Z.

2005-12-01

350

Radiation-hardened backside-illuminated 512 x 512 charge-coupled device  

NASA Astrophysics Data System (ADS)

A four-port 512 X 512 charge coupled device (CCD) imager hardened against proton displacement damage and total dose degradation has been fabricated and tested. The device is based upon an established thinned, backside illuminated, triple polysilicon, buried channel CCD process technology. The technology includes buried blooming drains. A three step approach has been taken to hardening the device. The first phase addressed hardening against proton displacement damage. The second phase addressed hardening against both proton displacement damage and total dose degradation. The third phase addresses final optimization of the design. Test results from the first and second phase efforts are presented. Plans for the third phase are discussed.

Bates, Philip A.; Levine, Peter A.; Sauer, Donald J.; Hsueh, Fu-Lung; Shallcross, Frank V.; Smeltzer, Ronald K.; Meray, Grazyna M.; Taylor, Gordon C.; Tower, John R.

1995-04-01

351

Bulk-hardened magnets based on Y2Co17  

Microsoft Academic Search

Bulk magnetic hardening of cast Y2Co17-based alloys was systematically studied for different compositions and heat treatments. Additions of Cu and Zr, Hf, or Ti to the Y–Co were found to be essential for developing coercivity. The performance of Y–Co–Cu–Zr magnets can be significantly improved by partial Pr and Fe substitutions for Y and Co, respectively. Anisotropic (Y0.8Pr0.2)11.5Zr2.75Co56.75Fe14Cu15 powders with intrinsic

A. M. Gabay; Y. Zhang; G. C. Hadjipanayis

2001-01-01

352

Bulk-hardened magnets based on Y2Co17  

Microsoft Academic Search

Bulk magnetic hardening of cast Y2Co17-based alloys was systematically studied for different compositions and heat treatments. Additions of Cu and Zr, Hf, or Ti to the Y-Co were found to be essential for developing coercivity. The performance of Y-Co-Cu-Zr magnets can be significantly improved by partial Pr and Fe substitutions for Y and Co, respectively. Anisotropic (Y0.8Pr0.2)11.5Zr2.75Co56.75Fe14Cu15 powders with intrinsic

A. M. Gabay; Y. Zhang; G. C. Hadjipanayis

2001-01-01

353

Individual variation in thermal responses of clothed women and men during repeated short-term cold-water immersions  

Microsoft Academic Search

Sudden immersion in cold water, resulting in a rapid and intense skin temperature drop, initiates physiological stress reactions collectively known as the ‘cold shock’ response. The aim of the present study was to investigate individual variations in body core and skin temperature responses induced by repeated short-term immersions of clothed subjects in cold water. Four medically screened healthy women aged

Raija Ilmarinen; Hannu Rintamäki; Harri Lindholm; Tero Mäkinen

2005-01-01

354

Effect of cold work and heat-treatment on the mechanical properties of a wire drawn metastable stainless steel  

Microsoft Academic Search

Tensile strengths in excess of 600×103 psi were obtained in a Type 18-8 stainless steel using relatively simple thermomechanical treatments involving cold working after solution annealing and intermittent heat-treatments. The strength developed strongly depended on the hardness and amount of martensite formed as well as the maintenance of high work-hardening rates at large deformation strains. For a given level of

John Nunes; Albert Martin

1975-01-01

355

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

356

Cold Regions Bibliography  

NSDL National Science Digital Library

A joint endeavor of the Federal Research Division of the Library of Congress and the US Army Cold Regions Research and Engineering Laboratory (CRREL), this project disseminates information on Antarctica and cold regions science and technology "by maintaining and continually updating a database which is an accumulation of over 40 years of materials on the science and technology of the world's cold regions." This database currently contains over 208,000 records, with about 6,000 accessions annually. After entering a supplied user id and password, users can search the database by keyword, author, or year of publication. Search returns include title, source, and a link to more information, including pages, notes, series, and publisher information. A DOS version of the database is also available for limited periods to qualified researchers. More information is available at the site.

357

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

358

Crazy Cold Air  

NSDL National Science Digital Library

This activity has students record the temperatures in and around a walk-in refrigerator or freezer to see how cold air behaves when it meets warmer air. The printable five-page handout includes a series of inquiry-based questions to get students thinking about how the temperature of air changes its density, detailed experiment directions, and a worksheet that helps students use experimental results to obtain insight into the wind patterns of Antarctica. They will observe why cold air rushes out of a freezer when you open the door and how it then moves through a room. Through this experiment the students gain insight into the blustery winds of Antarctica.

359

Induction of Cold Stability of Microtubules in Cultured Tobacco Cells  

PubMed Central

In suspension-cultured tobacco (Nicotiana tabacum) cells, we have often encountered cold-stable microtubules (MTs). The cold-stable MTs were found in the pelleted fraction of tobacco cell homogenates. These cold-stable MTs were shown to be accompanied by unidentified filamentous structures that extended along part of their length. However, during the early hours in culture such cold-stable MTs were never observed. They were detectable from 120 h after the beginning of subculture and then their numbers increased gradually. The number of cells with cold-stable MTs eventually accounted for more than 95% of the total population of cells at the stationary phase of culture. The rapid loss of cold stability of MTs occurred when such cells were transferred to fresh medium for subculture. However, if the fresh medium was supplemented with once-used medium, the cold stability of MTs was retained. The active agent in the medium appeared to be of low molecular weight and to be heat resistant. A similar activity was detected in a pectin hydrolyzate. When an inhibitor of protein kinase, either 6-dimethylaminopurine or staurosporin, was added to the cells at an early stage of culture, when cold-stable MTs were normally completely absent, most cells acquired cold-stable MTs. It appears that acquisition or loss of cold stability of MTs in tobacco cells is regulated by the action of a kinase/phosphatase or a phosphorylation/dephosphorylation system on some MT protein(s), such as a cold stabilizer of MTs, some unidentified MT-associated filamentous structure, or even tubulin itself. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Mizuno, Koichi

1992-01-01

360

Analysis on sheet cyclic plastic deformation using mixed hardening model  

NASA Astrophysics Data System (ADS)

Treating the cyclic deformation problem of sheet flowing through drawbead as the object of the research, using HILL anisotropy yield criterion and mixed hardening model, the cyclic plastic deformation mechanism of sheet was studied, the deformation characteristics of sheet subjected to cyclic loads were revealed, and the influence of Bauschinger effect on stress-strain circulating relationship and the influence of bending neutral layer migration on the stress of sheet's intermediate integral point were analyzed as well. The effectiveness of the model was verified by experiments. The results of analysis were showed that the stress values influenced by Bauschinger effect were different at the yield point of reverse loading and the point of unloading during the cyclic deformation. The stress rate at the yield point of reverse loading and the point of unloading in different loading branches was also different. The stress-strain circulating relationship in different loading branches can be approximately treated as bilinear. The tangent modulus of each loading branch showed a significant downward trend as the times of the reverse loading increased. The tangent modulus calculated by the mixed hardening model after the second loading branch reduced to less than 21% of the first loading tangent modulus. Effected by the neutral layer migration, the stress-strain curve of integral point of sheet's intermediate layer showed alternating transition phenomenon of the tensile stress and compressive stress.

Li, Qun; Jin, Miao; Yuxin, Zhu

2013-05-01

361

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

362

Koldstartsanalyse. (Cold start analysis).  

National Technical Information Service (NTIS)

During the period in which a petrol-driven private car is driven with a cold engine, it uses a richer petrol/air mixture in order to overcome carburation difficulties in the inlet manifold. This results in higher emission. With or without catalytic conver...

H. C. Thorsen H. Bendtsen

1994-01-01

363

Hot Talk, Cold Science  

Microsoft Academic Search

One of the hottest topics in climate science is understanding and evaluating the impacts of possible global warming caused by anthropogenic emissions of greenhouse gases. In Hot Talk, Cold Science, S. Fred Singer does not accept global warming. Singer says in his preface, ``The purpose of this book is to demonstrate that the evidence [for global warming] is neither settled,

Robert J. Oglesby

1998-01-01

364

Recent Cold War Studies  

ERIC Educational Resources Information Center

|Cold War historiography has undergone major changes since the 1991 collapse of the Soviet Union. For two years (1992-1993) the principal Soviet archives fell open to scholars, and although some of the richest holdings are now once again closed, new information continues to find its way out. Moreover, critical documentary information has become…

Pineo, Ronn

2003-01-01

365

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

366

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.

Tugel, Joyce; Keeley, Page

2009-03-01

367

The cold reading technique.  

PubMed

For many people, belief in the paranormal derives from personal experience of face-to-face interviews with astrologers, palm readers, aura and Tarot readers, and spirit mediums. These encounters typically involve cold reading, a process in which a reader makes calculated guesses about a client's background and problems and, depending on the reaction, elaborates a reading which seems to the client so uniquely appropriate that it carries with it the illusion of having been produced by paranormal means. The cold reading process is shown to depend initially on the Barnum effect, the tendency for people to embrace generalized personality descriptions as idiosyncratically their own. Psychological research into the Barnum effect is critically reviewed, and uses of the effect by a professional magician are described. This is followed by detailed analysis of the cold reading performances of a spirit medium. Future research should investigate the degree to which cold readers may have convinced themselves that they actually possess psychic or paranormal abilities. PMID:3360083

Dutton, D L

1988-04-15

368

The cold reading technique  

Microsoft Academic Search

Summary For many people, belief in the paranormal derives from personal experience of face-to-face interviews with astrologers, palm readers, aura and Tarot readers, and spirit mediums. These encounters typically involve cold reading, a process in which a reader makes calculated guesses about a client's background and problems and, depending on the reaction, elaborates a reading which seems to the client

D. L. Dutton

1988-01-01

369

Cold war thaws  

Microsoft Academic Search

The cold war on energy conservation seems to be thawing in the nation's capitol. After a decade of relentless attacks on energy conservation research and development budgets that left them 75% below their high water mark, the US Congress is embracing energy conservation as a vital ally. The authors describe all the current proposals in both the House and Senate

Totten

2009-01-01

370

Cold-Weather Sports  

MedlinePLUS

... Your Cool in the Cold and Snow Bad-Weather Driving Contact Us Print Additional resources Send to a friend Reprint guidelines Share this page using: What are these? Note: Clicking these links will take you to a site outside of KidsHealth's control.

371

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

372

Prevention of hand dermatitis in bakers' apprentices: different efficacy of skin protection measures and UVB hardening  

Microsoft Academic Search

Objective. The objective of this controlled intervention study was to quantify the efficacy of skin protection (SP) measures and ultraviolet B (UVB) hardening in the prevention of hand dermatitis in bakers' apprentices. Method. SP measures were compared against UVB hardening in a controlled clinical trial of 94 apprentices. The apprentices were assigned to the intervention arms class-wise. Bakers' apprentices involved

Andrea Bauer; Daniela Kelterer; Reinhard Bartsch; Anja Schlegel; James Pearson; Martina Stadeler; Peter Kleesz; Romano Grieshaber; Rainer Schiele; Peter Elsner; Hywel Williams

2002-01-01

373

Effect of laser surface hardening on En18 (AISI 5135) steel  

Microsoft Academic Search

Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshafts, lorry brake drums and gears. High power CO2 lasers and Nd–YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. All steel surfaces can

J. Senthil Selvan; K. Subramanian; A. K. Nath

1999-01-01

374

The determination of material strength coefficient and strain hardening constant by inverse method  

Microsoft Academic Search

In the process of metal plastic forming, the flow stress formula has always been a significant basis for analyzing plastic deformation. The material strength coefficient and strain hardening constant are the two major and indispensable parameters of the stress flow formula. According to the ASTM specifications, the traditional way of finding the material strength coefficient and strain hardening constant has

Zone-Ching Lin; Chang-Cheng Chen; Hsin-Ho Wang

2009-01-01

375

Thermal analysis of laser surface transformation hardening—optimization of process parameters  

Microsoft Academic Search

This paper deals with the optimization of process parameters for maximum productivity (given by the product of scanning velocity and cross feed) in laser transformation hardening. The process parameters considered are laser beam power, P; laser beam diameter, Db; and the heat intensity distribution, namely, normal, bimodal, or uniform. A thermal analysis of the laser surface transformation hardening of gears

R. Komanduri; Z. B. Hou

2004-01-01

376

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

377

Mathematical modeling of localized melting around graphite nodules during laser surface hardening of austempered ductile iron  

Microsoft Academic Search

An attempt has been made to mathematically predict the optimum conditions of laser surface hardening (LSH) of austempered ductile iron (ADI) that can ensure a predominantly martensitic microstructure and preclude partial\\/complete dissolution of graphite nodules in the laser hardened zone during laser irradiation. The exercise involves prediction of the thermal profile (using the Ashby and Easterling model), and consequently, the

A. Roy; I. Manna

2000-01-01

378

Stress Relaxation can Perturb and Prevent Physical Hardening in a Constrained Binder at Low Temperatures  

Microsoft Academic Search

The physical hardening phenomenon that is observed in asphalt binders held under isothermal conditions at low temperatures is found to be absent when the asphalt binder exists in combination with the aggregates in the aggregate-asphalt mixes. A recent study on the effect of physical hardening on stress relaxation behavior of asphalt binders has provided a plausible explanation for this observation.

Aroon Shenoy

2002-01-01

379

Investigating strength-inducing strains in hardened glasses with thermal-shock resistant compositions  

Microsoft Academic Search

Without dealing in this article with the matter of the supplementary increase in the strength of glasses during hardening as a result of the changes in the structure, let us dwell on the analysis of the mechanical factor of strength of hardened glasses due to the formation on their surfaces of strengthening strains of compression, and also on the connection

I. A. Boguslavskii; O. I. Pukhlik

1963-01-01

380

Simulation aided hardening of N-channel power MOSFETs to prevent single event burnout  

SciTech Connect

2D MEDICI simulator is used to investigate hardening solutions to single-event burnout (SEB). SEB parametric dependencies such as carrier lifetime reduction, base enlargement, and emitter doping decrease have been verified and a p{sup +} plug modification approach for SEB hardening of power MOSFETs is validated with simulations on actual device structures.

Dachs, C.; Palau, J.M.; Bruguier, G.; Gasiot, J. [Univ. Montpellier 2 (France); Roubaud, F. [Univ. Antilles Guyane, Kourou (French Guiana); Tastet, P. [CNES, Toulouse (France); Calvet, M.C. [Aerospatiale, Les Mureaux (France); Calvel, P. [Alcatel Espace, Toulouse (France)

1995-12-01

381

Cyclic hardening in copper described in terms of combined monotonic and cyclic stress-strain curves  

Microsoft Academic Search

Hardening of polycrystalline copper subjected to tension-compression loading cycles in the plastic region is discussed with reference to changes in flow stress determined from equations describing dislocation glide. It is suggested that hardening is as a result of the accumulation of strain on a monotonic stress-strain curve. On initial loading, the behaviour is monotonic. On stress reversal, a characteristic cyclic

H. D. Chandler

1995-01-01

382

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.

383

Cold Injury of Amputated Digits.  

National Technical Information Service (NTIS)

Patients who acquired an upper extremity nerve injury often complain about cold intolerance, reduced sensitivity and decreased task performance. This study tried to quantify these complaints and look in more detail at the thermal reaction to local cold ex...

U. Ahcan B. Luzar F. Bajrovic I. Mekjavic

2005-01-01

384

Cold Weather and Cardiovascular Disease  

MedlinePLUS

Cold Weather and Cardiovascular Disease Updated:Dec 11,2012 The fall and winter seasons will bring cooler temperatures, and ... and snow. It’s important to know how cold weather can affect your heart, especially if you have ...

385

Stay Safe in Cold Weather!  

MedlinePLUS

... Health and Aging » Publications Stay Safe in Cold Weather! What is hypothermia? Keep warm inside Bundle up ... to find more information Stay Safe in Cold Weather! Learn Why You Need to Stay Warm When ...

386

Prototype Cold Weather Face Mask.  

National Technical Information Service (NTIS)

An improved cold weather face mask has been developed which should provide protection from cold, wind, blowing snow, and frostbite in environments to -65F and 35 mph wind velocities. The mask provides physical compatibility with military clothing and equi...

D. Mangelsdorf M. Goldberg R. Colman S. Tobey

1971-01-01

387

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

388

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

SciTech Connect

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

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

2007-04-07

389

Paving Asphalt; Reduction of Oxidative Hardening of Asphalts by Treatment with Hydrated Lime-A Mechanistic Study.  

National Technical Information Service (NTIS)

This study showed that lime treatment removes polar, viscosity-building components and reduces the susceptibility of the asphalt to laboratory oxidative hardening. The beneficial effects of lime treatment in reducing asphalt oxidative hardening were attri...

H. Plancher E. L. Green J. C. Petersen

1977-01-01

390

Cold gas accretion in galaxies  

NASA Astrophysics Data System (ADS)

Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. H I observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent accretion: (1) A large number of galaxies are accompanied by gas-rich dwarfs or are surrounded by H I cloud complexes, tails and filaments. This suggests ongoing minor mergers and recent arrival of external gas. It may be regarded, therefore, as direct evidence of cold gas accretion in the local universe. It is probably the same kind of phenomenon of material infall as the stellar streams observed in the halos of our galaxy and M 31. (2) Considerable amounts of extra-planar H I have been found in nearby spiral galaxies. While a large fraction of this gas is undoubtedly produced by galactic fountains, it is likely that a part of it is of extragalactic origin. Also the Milky Way has extra-planar gas complexes: the Intermediate- and High-Velocity Clouds (IVCs and HVCs). (3) Spirals are known to have extended and warped outer layers of H I. It is not clear how these have formed, and how and for how long the warps can be sustained. Gas infall has been proposed as the origin. (4) The majority of galactic disks are lopsided in their morphology as well as in their kinematics. Also here recent accretion has been advocated as a possible cause. In our view, accretion takes place both through the arrival and merging of gas-rich satellites and through gas infall from the intergalactic medium (IGM). The new gas could be added to the halo or be deposited in the outer parts of galaxies and form reservoirs for replenishing the inner parts and feeding star formation. The infall may have observable effects on the disk such as bursts of star formation and lopsidedness. We infer a mean “visible” accretion rate of cold gas in galaxies of at least {0.2 M_{odot} year^{-1}} . In order to reach the accretion rates needed to sustain the observed star formation ({? 1 M_{odot} year^{-1}}), additional infall of large amounts of gas from the IGM seems to be required.

Sancisi, Renzo; Fraternali, Filippo; Oosterloo, Tom; van der Hulst, Thijs

2008-06-01

391

Remedies for Common Cold Symptoms  

PubMed Central

Individuals suffering from intolerable symptoms of the common cold can now be advised of safe and effective products for symptomatic relief. This article describes and discusses four categories of drugs used to treat the common cold. To simplify the product selection process for family physicians, suggestions are included for possible ingredients for treatments of specific cold symptoms.

Miller, Penny F.

1991-01-01

392

COLD WAR CULTURE AND RELIGION  

Microsoft Academic Search

In this course, we will adopt a different focus. We will emphasize the cultural processes through which people in the United States participated in, and came to understand, the cold war as a way of life. (This course deals with cold war culture and religion only in the U.S.) During the cold war, American citizens struggled to construct a \\

Ira Chernus

393

Cold response of dedifferentiated barley cells at the gene expression, hormone composition, and freezing tolerance levels: studies on callus cultures.  

PubMed

In this study, data is presented how dark-grown, embryogenic barley callus cells respond to cold without any light-dependent, chloroplast-related mechanism, independently of the systemic signals. The expression of HvCBF9, HvCBF14, and HvCOR14b genes, members of one of the most important cold-inducible regulatory system, was measured by real-time PCR. Characteristic of the cold response was similar in the crowns of seedlings and in dark-grown callus cultures, however, gene expression levels were lower in calli. Endogenous concentration of auxins, abscisic acid, and salicylic acid did not change, but phaseic acid and neophaseic acid showed robust accumulation after cold acclimation. Freezing tolerance of the cultures was also higher after 7 days of cold-hardening. The results suggest the presence of a basal, light-independent, cold-responsive activation of the CBF-COR14b pathway in barley cultures. The effects of Dicamba, the exogenous auxin analog used for maintaining tissue cultures were also studied. Dicamba seems to be a general enhancer of the gene expression and physiological responses to cold stress, but has no specific effect on the activation. Our data along with previous findings show that this system might be a suitable model for studying certain basic cellular mechanisms involved in the cold acclimation process in cereals. PMID:22669585

Vashegyi, Ildikó; Marozsán-Tóth, Zsuzsa; Galiba, Gábor; Dobrev, Petre I; Vankova, Radomira; Tóth, Balázs

2013-06-01

394

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

395

Theoretical Study of the Oxidation Behavior of Precipitation Hardening Steel  

NASA Astrophysics Data System (ADS)

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° 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.; Psyllaki, P.; Chrissafis, K.

2010-01-01

396

Topographies of plasma-hardened surfaces of poly(dimethylsiloxane)  

SciTech Connect

We studied the formation of surface layers hardened by plasma-enhanced oxidation of the silicone elastomer poly(dimethylsiloxane). We explored the largest parameter space surveyed to date. The surface layers may wrinkle, crack, or both, under conditions that at times are controlled by design, but more often have been discovered by trial-and-error. We find four distinct topographies: flat/wrinkled/cracked/cracked and wrinkled. Each topography is clearly separated in the space of plasma dose versus plasma pressure. We analyzed wrinkle amplitude and wavelength by atomic force microscopy in the tapping mode. From these dimensions we calculated the elastic modulus and thickness of the hard surface layer, and inferred a graded hardness, by employing a modified theoretical model. Our main result is the identification of the parameters under which the technologically important pure wrinkled, crack-free topography is obtained.

Goerrn, Patrick; Wagner, Sigurd [Department of Electrical Engineering and Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544 (United States)

2010-11-15

397

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

398

Gamma prime hardened nickel-iron based superalloy  

DOEpatents

A low swelling, gamma prime hardened nickel-iron base superalloy useful for fast reactor duct and cladding applications is described having from about 7.0 to about 10.5 weight percent (wt%) chromium, from about 24 to about 35 wt% nickel, from about 1.7 to about 2.5 wt% titanium, from about 0.3 to about 1.0 wt% aluminum, from about 2.0 to about 3.3 wt% molybdenum, from about 0.05 to about 1.0 wt% silicon, from about 0.03 to about 0.06 wt% carbon, a maximum of about 2 wt% manganese, and the balance iron.

Korenko, Michael K. (Richland, WA)

1978-01-01

399

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

400

Topographies of plasma-hardened surfaces of poly(dimethylsiloxane)  

NASA Astrophysics Data System (ADS)

We studied the formation of surface layers hardened by plasma-enhanced oxidation of the silicone elastomer poly(dimethylsiloxane). We explored the largest parameter space surveyed to date. The surface layers may wrinkle, crack, or both, under conditions that at times are controlled by design, but more often have been discovered by trial-and-error. We find four distinct topographies: flat/wrinkled/cracked/cracked and wrinkled. Each topography is clearly separated in the space of plasma dose versus plasma pressure. We analyzed wrinkle amplitude and wavelength by atomic force microscopy in the tapping mode. From these dimensions we calculated the elastic modulus and thickness of the hard surface layer, and inferred a graded hardness, by employing a modified theoretical model. Our main result is the identification of the parameters under which the technologically important pure wrinkled, crack-free topography is obtained.

Görrn, Patrick; Wagner, Sigurd

2010-11-01

401

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.

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

2010-01-01

402

Cold Drawn ERW Pipes with Superior Formability,  

National Technical Information Service (NTIS)

Cold drawn ERW pipes have been applied in various fields. Cold drawn pipes show recrystallized microstructures when they are annealed for softening. Cold drawn ERW pipes sometimes show a difficulty in formability during cold working of expanding, swaging ...

T. Adaniya T. Takamura T. Meada F. Nishimura M. Morimoto

1988-01-01

403

WISPy cold dark matter  

NASA Astrophysics Data System (ADS)

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; Cadamuro, Davide; Goodsell, Mark; Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas

2012-06-01

404

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

2012-06-26

405

Cold denaturation of ubiquitin  

Microsoft Academic Search

Temperature induced unfolding of bovine ubiquitin in solutions with different concentrations of guanidinium hydrochloride (GdmCl) has been measured using differential scanning calorimetry. It has been shown that at high concentrations of GdmCl the ubiquitin molecule can undergo both heat and cold induced denaturation. Analysis of the enthalpy of unfolding of ubiquitin in the presence of GdmCl shows a good agreement

Beatriz Ibarra-Molero; George I. Makhatadze; Jose M. Sanchez-Ruiz

1999-01-01

406

Cold Front Characteristics  

NSDL National Science Digital Library

In this activity, students will study animations of several atmospheric variables (air temperature, dew point, solar radiation, rainfall, and wind) to investigate the characteristics of weather produced by a cold front passage. Working in small groups, they will view animations from two different cases, identify patterns and changes, and answer questions about what they see. Links to a student worksheet, to the animations, and to viewing software are provided.

407

Crazy Cold Air  

NSDL National Science Digital Library

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

408

Cold nuclear fusion  

SciTech Connect

Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.

Tsyganov, E. N., E-mail: edward.tsyganov@utsouthwestern.edu [University of Texas Southwestern Medical Center at Dallas (United States)

2012-02-15

409

Rapid ejaculation  

Microsoft Academic Search

Rapid ejaculation, or premature ejaculatory dysfunction, is the most frequently encountered sexual complaint of men and couples.\\u000a It is most common in adolescents, young adults, and other sexually naive males. Increased risk is associated with lack of\\u000a sexual experience, lack of knowledge regarding normal male and female sexual responses, and with those individuals who highly\\u000a associate psychological factors (such as

Allen D. Seftel; Stanley E. Althof

2000-01-01

410

The Soviet Union and the Cold War: Assessing the Technological Dimension  

Microsoft Academic Search

The military competition engendered by the Cold War provoked rapid and sustained innovation in military technology. New information that has become available since the end of the Cold War permits a detailed reassessment of technical capabilities and developments in the Soviet Union, both with respect to strategic nuclear forces and to conventional weapons. This article shows that initially Soviet capabilities

Christoph Bluth

2010-01-01

411

Age hardening and the potential for superplasticity in a fine-grained Al-Mg-Li-Zr alloys  

SciTech Connect

Experiments were conducted to determine the age-hardening characteristics and the mechanical properties of an Al-5.5 pct Mg-2.2 pct Li-0.12 pct Zr alloy processed by equal-channel angular (ECA) pressing to give a very fine grain size of {approximately} 1.2 {micro}m. The results show that peak aging occurs more rapidly when the grain size is very fine, and this effect is interpreted in terms of the higher volume of precipitate-free zones in the fine-grained material. Mechanical testing demonstrates that the ECA-pressed material exhibits high strength and good ductility at room temperature compared to conventional Al alloys containing Li. Elongations of up to {approximately} 550 pct may be achieved at an elevated temperature of 603 K in the ECA-pressed condition, thereby confirming that, in this condition, the alloy may be a suitable candidate material for use in superplastic forming operations.

Furukawa, Minoru [Fukuoka Univ. of Education (Japan). Dept. of Technology; Berbon, P.B.; Langdon, T.G. [Univ. of Southern California, Los Angeles, CA (United States); Horita, Zenji; Nemoto, Minoru [Kyushu Univ., Fukuoka (Japan); Tsenev, N.K. [Ufa State Petroleum Technical Univ. (Russian Federation). Inst. of Chemical Technology; Valiev, R.Z. [Ufa State Aviation Technical Univ. (Russian Federation). Inst. of Physics of Advanced Materials

1998-01-01

412

Akt activation protects liver cells from apoptosis in rats during acute cold exposure.  

PubMed

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

2013-05-25

413

Identification of potential oviductal factors responsible for zona pellucida hardening and monospermy during fertilization in mammals.  

PubMed

Oviduct fluid increases the time required for digestion of the zona pellucida (ZP) by proteolytic enzymes (ZP hardening). This effect has been associated with levels of monospermy after in vitro fertilization (IVF) in the pig and cow, but the possible existence of a directly proportional relationship between hardening and monospermy remains unknown. To investigate whether variations in hardening of different oviductal fluids (OFs) are correlated with variations in levels of monospermy after IVF, porcine oocytes were incubated with three batches of OFs known to produce different ZP hardening effects (3, 7, and 25 min); after IVF, monospermy levels were 0%, 14.58% ± 5.14%, and 35.14% ± 7.95%, respectively. These results could partially explain the lack of polyspermy found during in vivo fertilization in pigs (with a hardened oviductal ZP) compared with levels found during IVF (with no hardened ZP). Using the bovine model, OF was fractionated by heparin affinity chromatography, and the hardening effect on the ZP was tested for each fraction obtained from a linear gradient of sodium chloride concentration. The highest effect was obtained with the fraction eluted with 0.4 M sodium chloride. Fractions with high-level or low-level effects were processed by on-chip electrophoresis and high-performance liquid chromatography-tandem mass spectrometry. A list of potential proteins responsible for this effect includes OVGP1 and members of the HSP and PDI families. PMID:23863406

Mondéjar, Irene; Martínez-Martínez, Irene; Avilés, Manuel; Coy, Pilar

2013-09-27

414

Isotopic diffusion in cold snow and firn  

NASA Astrophysics Data System (ADS)

Molecular mixing in cold snow and firn is ordinarily controlled by vapor diffusion. Diffusion through or along the ice matrix is slow, whereas diffusion from the air to within separate grains is comparatively rapid. Thus mixing occurs in the vapor phase, and exchange with the local ice involves all the water molecules. A quantification of these concepts is applied to the diffusion of oxygen-isotopic depth profiles in southern Greenland and at Dome C, Antarctica. It successfully describes the smoothing of measured profiles. The smoothing rate is strongly dependent on temperature and density of the firn.

Whillans, I. M.; Grootes, P. M.

1985-04-01

415

Review on Cold Spray Process and Technology: Part I—Intellectual Property  

Microsoft Academic Search

The number of research papers as well as of patents and patent applications on cold spray and cold spray related technologies\\u000a has grown exponentially in the current decade. This rapid growth of activity brought a tremendous amount of information on\\u000a this technology in a short period of time. The main motivation for this review is to summarize the rapidly expanding

Eric Irissou; Jean-Gabriel Legoux; Anatoly N. Ryabinin; Bertrand Jodoin; Christian Moreau

2008-01-01

416

Control of cold-hardening in the freeze-tolerant gall-fly larva, Eurosta solidaginis (Fitch) (tephrididae)  

Microsoft Academic Search

Quantitative differences exist in cryoprotectant accumulation patterns and ice nucleating activity between latitudinally distinct populations of the gall fly Eurosta solidaginis. The objectives of this study were the determination of the following: (1) what are the quantitative effects of temperature on polyol synthesis in E. solidaginis larvae. (2) What quantitative differences exist in response to warm acclimation and reacclimation to

1986-01-01

417

Seasonal changes in fatty acid composition associated with cold-hardening in third instar larvae of Eurosta solidaginis  

Microsoft Academic Search

Third-instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) survive extended periods in winter during which tissue water is frozen. Both low temperature and reduced\\u000a water activity during freezing present challenges for the structural integrity of cellular lipids. Fatty acids of both phospholipids\\u000a and triacylglycerols from fat body cells of E. solidaginis were analyzed throughout fall and early

Valerie A. Bennett; Nancy L. Pruitt; Richard E. Lee Jr.

1997-01-01

418

Rapid Heat Treatment of Aluminum High-Pressure Diecastings  

NASA Astrophysics Data System (ADS)

Recently, it has been demonstrated that common high-pressure diecasting (HPDC) alloys, such as those based on the Al-Si-Cu and Al-Si-Mg-(Cu) systems, may be successfully heat treated without causing surface blistering or dimensional instability. In some compositions, the capacity to exploit age hardening may allow the proof stress values to be doubled when compared to the as-cast condition. This heat treatment procedure involves the use of severely truncated solution treatment cycles conducted at lower than normal temperatures, followed by quenching and natural or artificial aging. The potential therefore exists to develop and evaluate secondary HPDC alloys designed specifically for rapid heat treatment, while still displaying high castability. This article reports results of an experimental program in which responses of various alloy compositions to age hardening have been investigated with the primary aim of further reducing the duration and cost of the heat treatment cycle while maintaining high tensile properties. Composition ranges have been established for which values of 0.2 pct proof stress exceeding 300 MPa ( i.e., increases of ~100 pct above as-cast values) can be achieved using a procedure that involves a total time for solution treatment plus age hardening of only 30 minutes. This rapid aging behavior is shown to be related to precipitation of the complex Q' phase, which forms primarily when Mg contents of the alloys are above ~0.2 wt pct.

Lumley, R. N.; Polmear, I. J.; Curtis, P. R.

2009-07-01

419

COLD FLOWS AND THE FIRST QUASARS  

SciTech Connect

Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBHs) have to be assembled within the first 800 million years. Under our standard galaxy formation scenario such fast growth implies large gas densities providing sustained accretion at critical or supercritical rates onto an initial black hole seed. It has been a long standing question whether and how such high black hole accretion rates can be achieved and sustained at the centers of early galaxies. Here we use our new MassiveBlack cosmological hydrodynamic simulation covering a volume (0.75 Gpc){sup 3} appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of {approx}10{sup 9} M{sub Sun} black holes as early as z {approx} 7. We find that under these conditions quasar feedback is not effective at stopping the cold gas from penetrating the central regions and hence cannot quench the accretion until the host galaxy reaches M{sub halo} > or approx. 10{sup 1}2{sup M}{sub Sun }. This cold-flow-driven scenario for the formation of quasars implies that they should be ubiquitous in galaxies in the early universe and that major (proto)galaxy mergers are not a requirement for efficient fuel supply and growth, particularly for the earliest SMBHs.

Di Matteo, T.; Khandai, N.; DeGraf, C.; Feng, Y.; Croft, R. A. C. [McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Lopez, J. [Computer Science Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Springel, V. [Heidelberg Institute for Theoretical Studies Schloss-Wolfsbrunnenweg 35, 68118 Heidelberg (Germany)

2012-02-15

420

Electrochemical cold fusion trials at IPP garching  

NASA Astrophysics Data System (ADS)

Following the report of Fleischmann and Pons,(1) we (The Bavarian Bubble Bottle Team) have attempted to reproduce their claims of cold nuclear fusion, and failed. We note that our measurements would not be able to detect neutrons at the level of Jones et al.(2) Three electrolytic cell experiments were conducted using palladium cathodes and Platinum anodes, in a 0.1-Molar solution of LiD in heavy water, without any signs of neutrons, tritium, or gammas above backgrounds, and within ±0.3 watt accuracy calorimetry, no excess heating. Excess heating at the levels of F&P would have been easily detected, if present. Intrinsic tritium, differing from each D2O bottle tested, was however observed. The longest duration experiment ran for 21 days, and was an attempt to duplicate the large "melting incident" of F&P. This was terminated on April 28, 1989, by throwing the vacuum-cast 22 gram, deuterium-loaded palladium cathode directly into liquid nitrogen, immediately next to a bare BF3 counter (backed by 25 cm of moderator), in order to attempt one of the Italian ENEA neutron production variants. No neutrons above backgrounds were seen, while counting for 1 hour, and also none while the piece warmed to room temperature over the next hour. Post-mortem analysis of the darkened, hardened Pd piece showed large crystal grains (up to 2 mm × 2 mm), and continuing evolution of gas bubbles at the grain boundaries even days after the experiment was ended. eight weeks after loading, the catalytically-active palladium piece continued to create heavy water (with exposure to oxygen in the air).

Bosch, H. S.; Wurden, G. A.; Gernhardt, J.; Karger, F.; Perchermeier, J.

1990-06-01

421

Hot Talk, Cold Science  

NASA Astrophysics Data System (ADS)

One of the hottest topics in climate science is understanding and evaluating the impacts of possible global warming caused by anthropogenic emissions of greenhouse gases. In Hot Talk, Cold Science, S. Fred Singer does not accept global warming. Singer says in his preface, “The purpose of this book is to demonstrate that the evidence [for global warming] is neither settled, nor compelling, nor even convincing. On the contrary, scientists continue to discover new mechanisms for climate change and to put forth new theories to try to account for the fact that global temperature is not rising, even though greenhouse theory says it should”.

Oglesby, Robert J.

422

Hot and Cold  

NSDL National Science Digital Library

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

Industry, Oregon M.

1997-01-01

423

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

SciTech Connect

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

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

2006-01-01

424

[Functional and metabolic changes of healthy volunteers after cold exposure and administration of meteoadaptogen trekrezan].  

PubMed

The effect of cold exposure (-10 degrees C, air speed--2.5 m/sec, 40 minutes) on physical activity, cognitive processes and metabolic status of 75 volunteers, healthy men of 20-24, was studied in termobarocomplex Tabaj (Japan). Cold exposure reduced physical and cognitive activity, the activity of kreatine phosphokinase, superoxide dismutase, the levels of redox glutation and pyruvate. Preliminary administration of adaptogenic drug trekrezan 0.2 g prior to cold exposure normalized the indexes studied of physical activity and metabolic status. It is suggested that trekrezan can be used as a meteoadaptogenic drug for rapid and effective adaptation to cold exposure of environment. PMID:18383733

Zarubina, I V; Ganapol'ski?, V P; Shabanov, P D

2008-01-01

425

Constraint effect on the near tip stress fields due to difference in plastic work hardening for bi-material interface cracks in small scale yielding  

Microsoft Academic Search

The change in near-tip stress field in Small Scale Yielding (SSY) for cracks located at an interface between two materials with different plastic work hardening is investigated. The difference in hardening is termed hardening mismatch, and is quantified through the parameter ?n, which is the difference in hardening exponent between the two materials. For cracks in elastic-ideally plastic materials the

E. Østby; Z. L. Zhang; C. Thaulow

2001-01-01

426

Constraint effect on the near tip stress fields due to difference in plastic work hardening for bi-material interface cracks in small scale yielding  

Microsoft Academic Search

The change in near-tip stress field in Small Scale Yielding (SSY) for cracks located at an interface between two materials with different plastic work hardening is investigated. The difference in hardening is termed hardening mismatch, and is quantified through the parametern , which is the difference in hardening exponent between the two materials. For cracks in elastic-ideally plastic materials the

E. ØSTBY; Z. L. ZHANG; C. THAULOW

2001-01-01

427

Interrelationships Between Thermal History and Mechanical Properties of a Secondary Hardening Steel.  

National Technical Information Service (NTIS)

Commercial secondary hardening steel, VASCO MA, has been subjected to modified heat treatments to introduce mixed microstructures of martensite and lower bainite. Dilatometry, tensile testing, hardness measurements and slow-bend testing have been carried ...

N. J. Kar

1976-01-01

428

Comparing the Bake Hardening of Nano-Grain AA6056 with its Coarse-Grain Structure  

NASA Astrophysics Data System (ADS)

In preset work, the bake hardening behavior of 6056 aluminum alloy with nanostructured layer, produced by surface severe plastic deformation (SSPD), was compared with that of AA6056 with conventional coarse grain structure. Wire brushing process was employed in order to produce surface layers with nanograins. After formation of nanostructured surface layer, the structure was characterized using X-ray Diffraction (XRD) and scanning electron microscopy (SEM) techniques. According to the microhardness measurements, the depth of nanostructured layer, with the grains of 50-110 nm, was about 40-50 ?m on each side of specimens. The bake hardenability of the produced nanostructured AA6056 was then studied. The results indicate an increase of about 40% in the bake hardening of nanograin AA6056 comparing to the bake hardening of coarse-grain AA6956. The maximum microhardness of nanograin layer was about 250 HV, whereas it was 65 HV for coarse-grain AA6056.

Dehghani, Kamran

429

Improvement in Surface Fatigue Life of Hardened Gears by High-Intensity Shot Peening.  

National Technical Information Service (NTIS)

Two groups of carburized, hardened, and ground spur gears that were manufactured from the same heat vacuum induction melted vacuum arc melted (VIM VAR) AISI 9310 steel were endurance tested for surface fatigue. Both groups were manufactured with a standar...

D. P. Townsend

1992-01-01

430

Honeywell radiation hardened 32-bit processor single event effects test results  

Microsoft Academic Search

We will present single event effects test results for the Honeywell radiation hardened 32-bit processor. The processor was tested at board-level while executing a signal and data processing benchmark suite

S. C. Leavy; Jeffrey A. Mogensen; Thomas S. Smith; G. J. Freitfeld; Julie Brichacek

1998-01-01

431

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

SciTech Connect

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

Flores, P.; Lelotte, T.; Bouffioux, C.; El Houdaigui, F.; Habraken, A.M. [Dept of Mechanics of Solids and Materials, Univ. de Liege, Chemin des Chevreuils 1, B-4000 Liege (Belgium); Duchene, L. [COBO Department, Royal Military Academy, Renaissancelaan 30, B-1000 Brussel (Belgium); Bael, A. van; He, S. [Department MTM, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Leuven (Belgium); Duflou, J. [Department PMA, Katholieke Universiteit Leuven, Celestijnlaan 300B, B3001 Leuven (Belgium)

2005-08-05

432

Southern Pine Pallets Assembled with Stiff-Stock and Hardened-Steel Pallet Nails.  

National Technical Information Service (NTIS)

The report describes the performance of two types (stiff stock and hardened) nails and two methods of installation (hand and machine) and the comparative value of each in the assembly of wooden pallets.

E. G. Stern

1972-01-01

433

The structural dependence of work hardening in low carbon steels  

SciTech Connect

The influence of the dislocation cell structure on the work hardening behavior of low carbon steel sheets was investigated. Specimens were prestrained at low temperature to suppress cell formation and their subsequent behavior was compared with results of isothermal reference tests. It was found that the extent of cell development has little or no influence on the plastic behavior at room temperature and below. Interrupted temperature, tensile-shear tests demonstrated further that the transient behavior induced by loading path changes is also not strongly associated with the cell walls. In-situ straining studies indicate that the factor controlling the flow stress at room temperature is the limited mobility of screw dislocations moving the cell interiors, and not dislocation interactions with the cell walls. The unique properties of a/2<111> screw dislocations are known to dominate low temperature deformation behavior in bcc metals. The current work indicates that these dislocations may still control the flow stress at intermediate temperatures, even in the presence of a developed cell structure.

Johnson, P.E.

1991-12-01

434

Radiation-hardened field coils for FMIT quadrupoles  

SciTech Connect

Modern accelerators of the Fusion Materials Irradiation Test (FMIT) class deliver enormous power onto their targets. The high beam currents of such machines produce highly activating radiation fields from beam/target interaction and normal beam losses. The 100-mA deuteron beam from the FMIT accelerator produces a backstreaming fast-neutron flux of 10/sup 11/ n/s-cm/sup 2/ near the target. In addition, the neutron contribution from distributed beam spill of 3 ..mu..A/m along the rest of the machine prevents the use of epoxy resin potting materials in all magnet field coils above 10-MeV beam energies. Two special techniques for radiation-hardened field coils have been developed at Los Alamos for use on the FMIT accelerator. One technique uses vitreous enamel coatings on the conductors and appears attractive for the drift-tube quadrupoles. Another method uses a thermally efficient two-layer coil design that has solid mineral-insulated (MI) conductors with indirect cooling coils, all bonded together in a lead matrix. Test results are discussed, along with applications of the quadrupoles in the FMIT facility that reduce gamma exposures during maintenance periods.

Grieggs, R.J.; Liska, D.J.; Harvey, A.

1983-01-01

435

Radiation hardening of final optics for an ICF reactor  

SciTech Connect

Radiation damage of the final optical components in an Inertial Confinement Fusion (ICF) reactor is a crucial issue for development of a laser-fusion reactor. To some extent, this problem will be encountered in the National Ignition Facility (NIF), but there, the integrated radiation dose will be considerably less than that encountered in a future reactor. This extremely harsh radiation environment necessitates shielding the ICF optics from direct neutron and x-ray bombardment. Several approaches have been suggested, such as the use of grazing incidence metal mirrors or fused silica wedge deflectors. While metal mirrors can withstand a larger radiation dose, their focusing qualities pose problems. Therefore wedge deflectors, originally suggested by Lawrence Livermore National Laboratory (LLNL) staff, represent a promising alternative. Radiation hardening of the fused silica deflectors using a new combined thermal/optical annealing approach is examined here as a method to maintain transmission quality during irradiation. By selection of suitable low impurity, fused silica materials combined with appropriate {ital in} {ital situ} treatment, such as discussed here, fused silica can be quite resistant to radiation effects. In addition, the wedge deflectors could be periodically replaced with minimal expense. {copyright} {ital 1996 American Institute of Physics.}

DelMedico, S.G.; Barnouin, O.M. [Rockford Technology Associates, Inc., 501 South Sixth Street, Suite 101, Champaign, Illinois 61820-5579 (United States); Petra, M.; Miley, G.H. [Fusion Studies Laboratory, University of Illinois, 100 NEL, 103 South Goodwin Avenue, Urbana, Illinois 61801-2984 (United States)

1996-05-01

436

Constitutive description of work- and shock-hardened copper  

SciTech Connect

Constitutive models are an essential part of large-scale computational codes which describe material behavior, since they provide the relationship between stress ([sigma]), strain ([epsilon]), strain rate ([epsilon]), and temperature (T). However, plastic deformation is an irreversible and path-dependent process, and a number of parameters affect the development of the deformation structure and, as a consequence, the mechanical response. The stress state, strain rate, and temperature affect the evolution of the microstructure, and the strain, current temperature and strain rate alone are frequently not sufficient to describe it. The constitutive equations that have been developed fall broadly into two groups: (a) empirical constitutive equations; (b) microstructural-based constitutive equations. Work-hardened metals may undergo dynamic recrystallization if the deformation temperature is in the range of 0.4 to 0.5 T[sub m], where T[sub m] is the absolute melting temperature. This dynamic recrystallization is accompanied by marked changes in the thermomechanical response of the material, which are not addressed by the constitutive equations discussed. The objective of this note is to develop a procedure for incorporating these important microstructural evolution elements into the constitutive equations that describe plastic deformation.

Andrade, U.R.; Meyers, M.A.; Chokshi, A.H. (Univ. of California, San Diego, CA (United States). Dept. of Applied Mechanics and Engineering Sciences)

1994-04-01

437

Precipitation hardened nickel-base alloys for sour gas environments  

SciTech Connect

SCC (Stress Corrosion Cracking) in sour gas environments of ..gamma..'(gamma prime: Ni/sub 3/(Ti and/or Al)) and ..gamma..''(gamma double prime: Ni/sub 3/Nb) precipitation hardened nickel-base alloys has been studied using the SSRT (Slow Strain Rate Tensile) test, anodic polarization measurement and transmission electron microscopy (TEM). The ..gamma..'-type alloy containing Ti was more susceptible to SCC in the SSRT tests up to 350/sup 0/F(450 K) than the ..gamma..''-type alloy containing Nb. The susceptibility to SCC was related to their deformation structures in terms of stress localization and sensitivity to pitting corrosion in H/sub 2/S solutions. TEM observation showed the ..gamma..'-type alloy deformed by the superlattice dislocations in coplanar structures. This mode of deformation induced the stress localization to some boundaries such as grain boundary and as a result the susceptibility to SCC of the ..gamma..'-type alloy was increased. On the other hand, the ..gamma..''-type alloy deformed by the massive dislocation not in coplanar structures so that it was less susceptible to SCC in terms of the stress localization. The anodic polarization measurement suggested the ..gamma..'-type alloy was more susceptible to pitting corrosion compared with the ..gamma..''-type alloy.

Igarashi, M.; Mukai, S.; Kudo, T.; Okada, Y.; Ikeda, A.

1987-01-01

438

Work Hardening Behavior in Steel with Multiple TRIP Mechanisms  

NASA Astrophysics Data System (ADS)

Transformation-induced plasticity (TRIP) behavior was studied in steel with the composition Fe-0.07C-2.85Si-15.3Mn-2.4Al-0.017N that exhibited two TRIP mechanisms. The initial microstructure consisted of both ?- and ?-martensites with 27 pct retained austenite. TRIP behavior in the first 5 pct strain was predominately austenite transforming to ?-martensite (Stage I), but upon saturation of Stage I, the ?-martensite transformed to ?-martensite (Stage II). Alloy segregation also affected the TRIP behavior with alloy-rich regions producing TRIP just prior to necking. This behavior was explained by first-principles calculations which revealed that aluminum significantly affected the stacking fault energy in Fe-Mn-Al-C steels by decreasing the unstable stacking fault energy and promoting easy nucleation of ?-martensite. The addition of aluminum also raised the intrinsic stacking fault energy and caused the ?-martensite to be unstable and transform to ?-martensite under further deformation. The two-stage TRIP behavior produced a high strain hardening exponent of 1.4 and led to an ultimate tensile strength of 1165 MPa and elongation to failure of 35 pct.

McGrath, M. C.; Van Aken, D. C.; Medvedeva, N. I.; Medvedeva, J. E.

2013-10-01

439

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

440

A radiation-hardened SOI-based FPGA  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

441

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 1.5-8.0 GPa. All experiments were performed on the Army Research Laboratory 102 mm bore single-stage light gas gun. Impact conditions were uniaxial and planar to within 1 mrad of tilt. Both direct-impact- and shock-transmission-type experiments were performed using velocity interferometry diagnostics to record particle velocity histories with 0.5 ns temporal resolution. The shock Hugoniot for 5083-H131 is extrapolated to 50 GPa 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

442

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

443

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

Microsoft Academic Search

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

Lumin Geng

2000-01-01

444

Combined mechanism for the hardening of a ZrO2-Y2O3 ceramic  

NASA Astrophysics Data System (ADS)

The phase composition and mechanical properties have been examined for a ZrO2-Y2O3 ceramic having a combined hardening mechanism, which was made by high-temperature sintering under vacuum. The mechanism enables one to alter the properties of the zirconium dioxide base ceramic substantially. The material has a combination of high strength and toughness because of the high viscosity of the untransformed part of the material, which produces an additional strengthening effect along with the transformational hardening.

Savchenko, N. L.; Sablina, T. Yu.; Kul'Kov, S. N.

1994-08-01

445

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

Microsoft Academic Search

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

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

2010-01-01

446

EÄect of material parameters on shear band spacing in work-hardening gradient dependent thermoviscoplastic materials  

Microsoft Academic Search

We study thermomechanical deformations of a viscoplastic body deformed in simple shear. The eÄect of material elasticity is neglected but that of work hardening, strain-rate hardening, thermal softening, and strain-rate gradients is considered. The consideration of strain-rate gradients introduces a material characteristic length into the problem. A homogeneous solu- tion of the governing equations is perturbed at diÄerent values t0

L. Chen; R. C. Batra

1999-01-01

447

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

448

Ramberg-Osgood strain-hardening characterization on an ASTM A302B steel  

Microsoft Academic Search

Many elastic-plastic fracture mechanisms analysis procedures require knowledge of the true stress versus true strain response of the material being analyzed. The most common strain-hardening relationship employed is of the form first proposed by Ramberg and Osgood. Here, the Ramberg-Osgood strain-hardening exponents and coefficients are characterized for an unirradiated ASTM A302-B steel over a wide range of temperatures from -129

L. A. James

1995-01-01

449

Surface hardening of Ti-6Al-4V alloy by electrochemical hydrogenation  

SciTech Connect

Surface hardening of Ti-6Al-4V alloy can be performed by electrolytic charging in acid and basic solutions, with or without subsequent solution treatment, followed by dehydrogenation to obtain equiaxed [alpha] grains in a transformed [beta] matrix. Surface hardnesses of the processed specimens are better than that of the mill-annealed specimen. The depth of the hardened layer depends on the processing parameters.

Tair-I Wu (Tatung Inst. of Tech., Taiwan (China)); Jiann-Kuo Wu (National Taiwan Ocean Univ. (China))

1993-05-01

450

The strain-hardening effect in HRR plane fields according to T-criterion  

Microsoft Academic Search

The strain-hardening effect on fracture is investigated with the aid of the T-criterion using HRR stress fields [1–3] around a crack tip in a power hardening material. Using the appropriate components of strain energy density for the elastic-plastic as well as a nearly elastic expression of the T-criterion, we find the fracture angles, as well as fracture stresses in materials

Pericles S. Theocaris; C. B. Demakos

1994-01-01

451

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

452

Precipitation hardening of a Cu-free Au–Ag–Pd–In dental alloy  

Microsoft Academic Search

The hardening mechanism and related microstructural changes of the Cu-free dental casting alloy composed of Au–Ag–Pd–In was examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The Au–Ag–Pd–In alloy showed apparent age-hardenability. In the SEM photograph, three phases were observed in the solution-treated specimen, that is, the Au–Ag based phase

Hyo-Joung Seol; Kuk-Hyeon Son; Chin-Ho Yu; Yong Hoon Kwon; Hyung-Il Kim

2005-01-01

453

Alloy hardening of a smectic A liquid crystal doped with gold nanoparticles  

NASA Astrophysics Data System (ADS)

We measure the mobility of edge dislocations in a smectic A liquid crystal doped with gold nanoparticles. The mobility is found to decrease when the concentration of nanoparticles increases, which leads to a hardening of the smectic phase. It is found that the closer the temperature to the nematic phase, the weaker the hardening. The critical behavior of the mobility near the smectic A-to-nematic transition temperature is also investigated and compared to theoretical predictions.

Oswald, P.; Milette, J.; Relaix, S.; Reven, L.; Dequidt, A.; Lejcek, L.

2013-08-01

454

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

455

Fatigue characteristics and fatigue limit prediction of an induction case hardened Cr–Mo steel alloy  

Microsoft Academic Search

In this study, a structural Cr–Mo steel alloy is used to investigate the effect of residual stresses and the presence of micro-holes on the fatigue strength for the base metal and the induction case hardened specimens. The samples are tested using rotary bending. Micro-hole diameter and case hardening depth are used as varying parameters. For the prediction of the fatigue

Sam-Hong Song; Byoung-Ho Choi

2003-01-01

456

Tool wear when turning hardened AISI 4340 with coated PCBN tools using finishing cutting conditions  

Microsoft Academic Search

Tool wear is one of the most important aspects in metal cutting, especially when machining hardened steels. The present work shows the results of tool wear, cutting force and surface finish obtained from the turning operation on hardened AISI 4340 using PCBN coated and uncoated edges. Three different coatings were tested using finishing conditions: TiAlN, TiAlN-nanocoating and AlCrN. The lowest

Reginaldo T. Coelho; Eu-Gene Ng; M. A. Elbestawi

2007-01-01

457

Effect of Pd or Au addition on age-hardening in AgMn-based alloys  

Microsoft Academic Search

Objective: The objective of this research was to characterize the age-hardening behavior of AgMn alloys modified with Au or Pd. These alloys are being studied as possible alternatives to Type III dental alloys.Methods: The age-hardening reactions in Ag-37at% Mn alloys with 5at% Au or Pd were investigated by optical microscopy, electrical resistivity, X-ray diffraction and hardness tests.Results: Optical microscopy showed

I Kawashima; H Ohno; N. K Sarkar

2000-01-01

458

Statistical Approach to A Leaner Sinter Hardening P\\/M Alloy  

Microsoft Academic Search

A popular sinter-hardening alloy is based on pre-alloyed Fe-Ni-Mo-Mn powder to which 2% copper and 0.9% graphite is added. Data in the literature suggests that reduced copper and graphite contents may provide equal hardenability and higher tensile properties. Experimental results demonstrate that a fully martensitic microstructure and higher tensile properties may be obtained with leaner alloy chemistry. Reduced additive (copper

Gerald A. Gegel; Michael A. Pershing; Thomas F. Murphy; Gerard J. Golin

459

Calculation of the pipeline wall thickness under internal pressure at an arbitrary law of hardening  

NASA Astrophysics Data System (ADS)

A semianalytical solution is obtained for the problem of the deformation of a hollow cylinder (tube) subjected to internal pressure for the material that meets the Tresca plasticity condition and obeys an arbitrary law of hardening. The solution is analytical for linear hardening. This solution can be used to take into account the bearing capacity of a material in strength calculations more completely and reliably as compared to the existing techniques by choosing the cylinder wall thickness.

Alexandrov, S. E.; Goldstein, R. V.

2012-10-01

460

Occupational allergic contact dermatitis and contact urticaria caused by polyfunctional aziridine hardener.  

PubMed

Polyfunctional aziridine (PFA) is increasingly used as a water-based cross-linker in 2-component paints, paint primers, lacquers, topcoats and other protective coatings. The cross-linker (PFA hardener) is made by reacting multifunctional acrylic monomer with a highly reactive aziridine compound. During 1992-1993, we came across 2 patients with allergic patch test reactions provoked by PFA hardener. One of the patients was a parquet layer, and the other a printer. Allergic contact dermatitis (ACD) was diagnosed by positive allergic patch test reactions to PFA hardener in a dilution series in pet.:0.3%-1% gave ++ to allergic reactions in both patients, whereas 0.1% gave a weak (+) or questionable reaction (?+), respectively. The methacrylate patch test series was negative in both patients, although gas chromatography/mass spectrometry analysis showed that PFA hardener contained 0.3% of trimethylolpropane triacrylate (TMPTA), a multifunctional acrylic monomer. One of the patients also had symptoms of contact urticaria, and a prick test with PFA hardener (1% aq.) induced a histamine-sized prick test reaction. The positive reactions with the PFA hardener and the negative reactions with the starting chemicals and additives in PFA, namely acrylates, propyleneimine and dimethylethanolamine, indicate that PFA caused ACD. This is in accordance with our previous observations, but differs from the reports of others, whose patients had been sensitized to acrylates present as remnants in the PFA hardener. As test substance, 0.5% PFA hardener in pet. is recommended for patch testing. Testing should be performed in patients with contact dermatitis if exposure to PFA has occurred. Skin prick tests may be of help to detect contact urticaria. PMID:8565484

Kanerva, L; Estlander, T; Jolanki, R; Tarvainen, K

1995-11-01

461

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

462

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

463

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

SciTech Connect

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

Oliveira, M.C.; Menezes, L. F. [CEMUC, Department of Mechanical Engineering, University of Coimbra, Polo II, 3030 Coimbra (Portugal); Alves, J.L. [Department of Mechanical Engineering, University of Minho, Campus de Azurem, 4800-058 Guimaraes (Portugal); Chaparro, B.M. [Polythecnic Institute of Tomar, Rua 17 de Agosto de 1808, 2200-273 Abrantes (Portugal)

2005-08-05

464

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

NASA Astrophysics Data System (ADS)

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

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

2005-08-01

465

Human Vascular Fluid Responses to Cold Stress Are Not Altered by Cold Acclimation.  

National Technical Information Service (NTIS)

Repeated cold water immersion can induce the development of an insulative type of cold acclimation in man. This investigation determined if repeated cold water immersion produced changes in vascular fluid response to cold stress in addition to the previou...

A. J. Young S. R. Muza M. N. Sawka K. B. Pandolf

1986-01-01

466

Control of ion transport by mitochondrion-rich chloride cells of eurythermic teleost fish: Cold shock vs. cold acclimation.  

PubMed

Seawater-acclimated eurythermic mummichogs (Fundulus heteroclitus L.) were acclimated to cold and warm conditions (5 and 20 °C, 4 weeks). Opercular epithelia (OE) from 20 °C-acclimated animals, containing numerous mitochondrion-rich chloride cells were mounted in Ussing-style membrane chambers, cooled to 16, 13, 10, 5 and 2.5 °C, then subjected to hypotonic shock that normally inhibits Cl(-) secretion (as short-circuit current, I(sc)). Cold exposure to 10 °C slowed Cl(-) secretion (Q(10)=1.62 ± 0.204 95% CI) and OEs responded rapidly and reversibly to hypotonic shock, but below 8.0 °C a sharp decrease (Q(10)=5.63 ± 0.736) occurred and the tissue was unresponsive to hypotonicity. By immunocytochemistry, Focal Adhesion Kinase (FAK) phosphorylated at tyrosine-407 (pY(407)) colocalized with CFTR in apical membrane and dephosphorylated with hypotonic shock at 20 °C but failed to dephosphorylate at 5 °C, while opercular epithelia from cold-acclimated fish at 5 and 20 °C responded normally to hypotonic shock. Cold-shock of warm-acclimated OEs also stimulated covering over of mitochondrion- rich cell apical crypts, detected by SEM. Cold-acclimation increased C18:1 and decreased C18:0 fatty acids in liver, indicating homeoviscous adaptation. Eurythermic fish acclimate osmoregulatory systems to cold by maintaining membrane fluidity and preserving complex transport regulation pathways. PMID:22465000

Buhariwalla, H E C; Osmond, E M; Barnes, K R; Cozzi, R R F; Robertson, G N; Marshall, W S

2012-03-23

467

Cold quark matter  

NASA Astrophysics Data System (ADS)

We perform an O(?s2) perturbative calculation of the equation of state of cold but dense QCD matter with two massless and one massive quark flavor, finding that perturbation theory converges reasonably well for quark chemical potentials above 1 GeV. Using a running coupling constant and strange quark mass, and allowing for further nonperturbative effects, our results point to a narrow range where absolutely stable strange quark matter may exist. Absent stable strange quark matter, our findings suggest that quark matter in (slowly rotating) compact star cores becomes confined to hadrons only slightly above the density of atomic nuclei. Finally, we show that equations of state including quark matter lead to hybrid star masses up to M˜2M?, in agreement with current observations. For strange stars, we find maximal masses of M˜2.75M? and conclude that confirmed observations of compact stars with M>2M? would strongly favor the existence of stable strange quark matter.

Kurkela, Aleksi; Romatschke, Paul; Vuorinen, Aleksi

2010-05-01

468

Cold / Smallest Ice  

NSDL National Science Digital Library

This radio broadcast contains a discussion with the author of a book about history, heat, and the quest for absolute zero. Absolute zero, (-273.15 degrees Celsius), the temperature at which all molecules stop moving entirely, is ultimately cold. Research into what temperature really means and ways to alter the temperature of objects has resulted in more efficient engines, air conditioning, new materials, and even a new form of matter, the Bose-Einstein Condensate. The broadcast also contains discussion about researchers who say that they have made the smallest piece of ice possible - a hexagonal shape built out of just six molecules of water. (A normal drop of water contains about 100,000,000,000,000,000,000 water molecules). The research may help the scientists examine how water molecules bond together, information of great interest to biologists, chemists, and pharmaceutical researchers. The broadcast is 47 minutes in length.

469

Nonfreezing Cold-Induced Injuries.  

National Technical Information Service (NTIS)

Nonfreezing cold-induced injury (NFCI) is a clinical syndrome that results from damage caused to tissues exposed to cold temperatures at or above the freezing point of water (0 deg to 15 deg C 32 deg to 59 deg F). NFCI does not involve tissue freezing, wh...

C. H. Imray J. W. Castellani

2012-01-01

470

Caffeine and the common cold  

Microsoft Academic Search

An experiment was carried out to determine whether caffeinated and decaffeinated coffee removed the malaise (reduced alertness, slower psychomotor performance) associated with having a common cold. One hundred volunteers were tested when healthy and 46 returned to the laboratory when they developed colds. Those subjects who remained healthy were then recalled as a control group. On the second visit subjects

Andrew Smith; Marie Thomas; Kate Perry; Helen Whitney

1997-01-01

471

Nanofriction in cold ion traps  

Microsoft Academic Search

Sliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show static friction or slip with dynamic friction; cold ions are known to form static chains, helices or clusters, depending on the trapping conditions. Here we show, based on simulations, that much could be learnt about

A. Benassi; A. Vanossi; E. Tosatti

2011-01-01

472

Hypothermia and localized cold injuries  

Microsoft Academic Search

Accidental hypothermia and localized cold injuries remain a significant public health problem. The deleterious effect of cold exposure on human performance and health has been documented for centuries. Some of the earliest descriptions came from Baron de Larrey, Napoleon's chief surgeon. During the disastrous invasion of Russia in 1812 he depicted the mental and physical hardships endured by the French

Andrew S. Ulrich; Niels K. Rathlev

2004-01-01

473

Microscopic Mechanism for Cold Denaturation  

Microsoft Academic Search

We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect induces, facilitates, and is the driving force for cold denaturation. The physical mechanism underlying this phenomenon is identified