These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Fitness costs of rapid cold-hardening in Ceratitis capitata.  

PubMed

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

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

2012-01-01

2

Rapid cold hardening of Thrips palmi (Thysanoptera: Thripidae).  

PubMed

Cold tolerance of the palm thrips, Thrips palmi Karny, was investigated to predict its survival in field during winter. Supercooling points of T. palmi were varied among the developmental stages and ranged from -26.4 to -18.4°C. However, the cold injuries occurred above supercooling points in terms of higher mortality. The exposure to subzero temperatures (-5° to -15°C) resulted in significant mortalities to all developmental stages of T. palmi. A preexposure to a low temperature (4°C) for 7 h significantly increased the cold tolerance of all stages of T. palmi with respect to survival at -10°C and supercooling capacity. The rapid cold hardening (RCH) was dependent on the duration of the preexposure period at 4°C in adult stage. Polyol and sugar analysis using an high-performance liquid chromatography analysis showed that 4°C preexposure caused accumulation of glycerol, trehalose, mannitol, and mannose in the adults. The increase in trehalose levels was more significant than the others. This study suggests that all stages of T. palmi are able to become cold-hardy by RCH, in which several polyols and sugars may play crucial roles as cryoprotectants. PMID:25182622

Park, Youngjin; Kim, Kwangho; Kim, Yonggyun

2014-08-01

3

A specific glycerol kinase induces rapid cold hardening of the diamondback moth, Plutella xylostella.  

PubMed

Insects in temperate zones survive low temperatures by migrating or tolerating the cold. The diamondback moth, Plutella xylostella, is a serious insect pest on cabbage and other cruciferous crops worldwide. We showed that P. xylostella became cold-tolerant by expressing rapid cold hardiness (RCH) in response to a brief exposure to moderately low temperature (4°C) for 7h along with glycerol accumulation in hemolymph. Glycerol played a crucial role in the cold-hardening process because exogenously supplying glycerol significantly increased the cold tolerance of P. xylostella larvae without cold acclimation. To determine the genetic factor(s) responsible for RCH and the increase of glycerol, four glycerol kinases (GKs), and glycerol-3-phosphate dehydrogenase (PxGPDH) were predicted from the whole P. xylostella genome and analyzed for their function associated with glycerol biosynthesis. All predicted genes were expressed, but differed in their expression during different developmental stages and in different tissues. Expression of the predicted genes was individually suppressed by RNA interference (RNAi) using double-stranded RNAs specific to target genes. RNAi of PxGPDH expression significantly suppressed RCH and glycerol accumulation. Only PxGK1 among the four GKs was responsible for RCH and glycerol accumulation. Furthermore, PxGK1 expression was significantly enhanced during RCH. These results indicate that a specific GK, the terminal enzyme to produce glycerol, is specifically inducible during RCH to accumulate the main cryoprotectant. PMID:24973793

Park, Youngjin; Kim, Yonggyun

2014-08-01

4

ORIGINAL PAPER Rapid cold-hardening blocks cold-induced apoptosis by inhibiting  

E-print Network

body, midgut, muscle, and Malpighian tubules from adult flesh flies Sarcophaga crassipalpis to test fractions of fat body and muscle extracts compared to controls. Keywords Apoptosis Á Caspases Á Cold shock Á changes in the apoptotic cells include blebbing, loss of membrane asymmetry and attachment, cell shrink

Lee Jr., Richard E.

5

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

PubMed

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

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

2012-11-01

6

Introduction More than 15years ago, we reported a rapid cold-hardening  

E-print Network

that RCH also allows an organism's overall cold tolerance to track changes in environmental temperature of the terrestrial chironomid Belgica antarctica extends further south than any other free-living holometabolous in Antarctica (Usher and Edwards, 1984; Sugg et al., 1983). This endemic species is sporadically dispersed

Lee Jr., Richard E.

7

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. PMID:18342328

Rajamohan, Arun; Sinclair, Brent J.

2008-01-01

8

Low-temperature tolerance and cold hardening of cacti  

SciTech Connect

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

9

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

10

Use of rapidly hardening hydroxyapatite cement for facial contouring surgery.  

PubMed

Hydroxyapatite cement is an ideal alloplastic material to replace the autogenous bone grafts in craniofacial surgery. Hydroxyapatite cement is advantageous because it can be easily molded by hand unlike other alloplastic materials such as silicone and high-density polyethylene. For aesthetic applications of hydroxyapatite cement, we evaluated the efficacy and safety of the rapidly hardening hydroxyapatite cement used in facial contour augmentation, especially for the forehead and the malar area. A total of 18 cases of facial skeleton augmentation or contouring surgery using rapidly hardening hydroxyapatite cement (Mimix; Biomet, Warsaw, IN) were examined, and the long-term cosmetic results and any complications were also analyzed. The aims of facial contouring surgeries were to correct the following conditions: hemifacial microsomia, craniosynostosis, posttraumatic facial deformity, deformity after tumor resection, dentofacial deformity, and Romberg disease. The application sites of hydroxyapatite cement were the forehead, malar area, chin, and paranasal area. A mean of 16 g (range, 5-50 g) of the hydroxyapatite cement was used. Postoperative infection, seroma, and migration of the implant were not observed during the follow-up period of 23 months. Rapidly hardening hydroxyapatite cement, Mimix, is easy to manipulate, promptly sclerotized, and can be replaced by living bone tissue, with a low complication rate. Therefore, it can be an optimal treatment that can be used instead of other conventional types of alloplastic materials used in facial contouring surgery. PMID:20613576

Lee, Dong Won; Kim, Ji Ye; Lew, Dae Hyun

2010-07-01

11

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

12

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

PubMed Central

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

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

1982-01-01

13

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

NASA Astrophysics Data System (ADS)

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

Cunningham, J. L.; Medlin, D. J.; Krauss, G.

1999-08-01

14

Phenomenon of strain hardening behaviour of sintered aluminium preforms during cold axial forming  

Microsoft Academic Search

Cold upsetting experiments were carried out on sintered aluminium preforms in order to evaluate their work-hardening characteristics. Aluminium powder preforms of 92% of theoretical density, with three initial aspect ratios were prepared using a suitable die-set assembly on a 1.0MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for a period of 1 hour at

N Selvakumar; R Narayanasamy

2003-01-01

15

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

16

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

17

Cold work hardening in stages IV and V of f. c. c. metals. I. Experiments and interpretation  

Microsoft Academic Search

The paper presents numerous measurements which confirm stages IV and V to be general ranges of cold work deformation. Analogous to stage II, stage IV exhibits a linear athermal hardening with constant strain rate sensitivity and activation enthalpy. In stage IV the dislocation cell size is constant, while the dislocation density growth rate is markedly reduced compared with stages II

M. Zehetbauer; V. Seumer

1993-01-01

18

A semi-physiological model of cold hardening and dehardening in walnut stem.  

PubMed

It has been hypothesized that the increase in temperature in this century could lead to an increase in frost damage to plant tissues. Several models have been proposed to describe the development of cold hardiness, but never taking into account extreme climatic and/or physiological events. Our results on walnut tree (Juglans regia L.) show that cold hardiness was best correlated with average daily temperatures minimal temperatures over the last 15 days before sampling (T(min 15 days)), indicating that the freezing tolerance depended on the tree's climatic history. Moreover, this study also shows that the accumulation of sucrose and the water content (WC) decrease are an essential step towards cold hardiness. Thus, a simple linear model based on climatic (T(min 15 days)) and physiological (soluble sugars, WC) explanatory variables was developed to predict the cold hardiness level in walnut stem at any time during the leafless period. Each of the three input variables can be assigned a specific role contributing to the simulated function, cold hardiness. The extent and robustness of this relation was assessed on extreme physiological events on walnut trees bearing three main branches. On each tree, one branch was defoliated to limit the local carbohydrate and transpiration, one was girdled to increase local carbohydrate and prevent carbohydrate export and the third one was kept untreated as control. As expected, these treatments impacted both local carbon reserves and WC in the stems born by each main branch in comparison with the control on the same tree. The impact of these treatments on stem's freezing tolerance, as evaluated by an electrolyte leakage method (LT??), confirmed the direct impact of soluble sugar and WC on cold hardiness over a wide range of carbohydrate and WC. This is discussed in relation to the branch autonomy theory for carbon but also for water during summer growth and winter periods. The present study demonstrates the importance of physiological parameters in the prediction of cold hardiness and proposes a way to model cold hardiness with extreme climatic and/or physiological events. PMID:21030404

Poirier, Magalie; Lacointe, André; Améglio, Thierry

2010-12-01

19

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

20

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

PubMed Central

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

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

2013-01-01

21

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

2013-01-01

22

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

23

No snow-plough mechanism during the rapid hardening of supermassive black hole binaries  

E-print Network

We present two-dimensional 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 one-dimensional 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 snow-plough 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 snow-plough mechanism is unlikely to occur. In two-dimensions, when the binary's hardening timescale driven by gravitational radiation becomes shorter than the disc's viscous drift timescale, fluid elements in the inner disc get funneled to the outer disc through horseshoe trajectories with resp...

Baruteau, Clément; Masset, Frédéric

2012-01-01

24

RAPID SOLUTION HARDENING AT ELEVATED TEMPERATURES BY SUBSTITUTIONAL Re ALLOYING IN  

E-print Network

is a potential material for high temperature structural applications primarily due to its high melting point which may pair with Re substitutionals to form point defect complexes. A model that describes the elliptical strain ®eld (tetragonal distortion) around these point defects is used to interpret the rapid

25

Cold work hardening in stages IV and V of f. c. c. metals. II. Model fits and physical results  

Microsoft Academic Search

The paper presents a common concept for work hardening of f.c.c. metals at temperatures below 0.5 T[sub m] up to very high strains. The concept considers statistical dislocation dynamics in terms of screw and edge dislocations and their specific interactions, and also allows for deformation-induced vacancies. By fitting the concept equations to experiment and using measured interaction parameters, very good

M ZEHETBAUER

1993-01-01

26

Rapid allergen inactivation using atmospheric pressure cold plasma.  

PubMed

Allergies have become a global problem, and effective control is greatly needed. Here, the inactivation effects of the atmospheric pressure cold plasma (APCP) on aerosolized allergens including Der p 1, Der f 1, Asp f 1, Alt a 1, and Can f 1 as well as those from indoor and outdoor environments were investigated. The effectiveness of the APCP treatment was further studied using blood sera from the allergen sensitized humans. In addition, the allergen samples were also analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Results revealed that the APCP was highly effective in reducing the allergenicity of both lab-prepared and environmental allergen aerosols. The airborne reductions were shown to range from 30% for Der p 1 to 80% for Can f 1 allergen for 0.12 s exposure. Allergnicity tests showed that the APCP treated Asp f 1 allergens caused 50% less binding with IgEs in the blood sera compared to the control. The observed allergenicity loss was due to hydroxyl radicals produced by the plasma device. The results from SDS-PAGE showed that the plasma treatment resulted in decreased size of the Asp f 1 allergen. The developed technology holds great promise in combating the allergic diseases. PMID:24490983

Wu, Yan; Liang, Yongdong; Wei, Kai; Li, Wei; Yao, Maosheng; Zhang, Jue

2014-03-01

27

Rapid remobilization of magmatic crystals kept in cold storage  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

28

Rapid remobilization of magmatic crystals kept in cold storage.  

PubMed

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

Cooper, Kari M; Kent, Adam J R

2014-02-27

29

Rapid and sensitive FAME analysis of bacteria by cold trap injection gas chromatography  

Microsoft Academic Search

Whole cell fatty acid analysis is commonly used to identify bacteria. A cold trap, using a commercially available device that directs a stream of compressed air across a section of the GC column, is used to focus peaks at the head of the column. When combined with a rapid sample processing method that uses smaller volumes of solvents, it becomes

Jeffrey S. Buyer

2006-01-01

30

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

Microsoft Academic Search

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

Jeom-Yong Choi; Won Jin

1997-01-01

31

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

32

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

33

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

E-print Network

A Method for Rapid Measurement of Heat or Cold Resistance of Small Insects R. B. Huey; W. D. Crill measurement of heat or cold resistance of small insects R. B. HUEY, W. D. CRILL, J. G. KINGSOLVER and K. E technique for rapidly measuring the heat or cold resistance of many small insects. We heat (or cool) insects

Huey, Raymond B.

34

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

35

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

36

Surface Fatigue Resistance with Induction Hardening  

NASA Technical Reports Server (NTRS)

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

Townsend, Dennis; Turza, Alan; Chapman, Mike

1996-01-01

37

Stress State of 12% Ni Maraging Steel After a Modified Procedure of Precipitation Hardening  

Microsoft Academic Search

Fatigue resistance of a surface layer of dynamically and thermomechanically loaded machine components and tool parts can be improved with a combination of mechanical hardening by cold deformation and thermal precipitation hardening. One of the mechanical processes of surface hardening is a relatively simple and accessible process of roto peening. The hardening effect of roto peening is related to a

J. Grum; M. Zupan?i?

2009-01-01

38

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

39

Hydraulic Signals from the Roots and Rapid Cell-Wall Hardening in Growing Maize (Zea mays L.) Leaves Are Primary Responses to Polyethylene Glycol-Induced Water Deficits.  

PubMed Central

We investigated mechanisms involved in inhibition of maize (Zea mays L.) leaf-elongation growth following addition of non-penetrating osmolyte to the root medium. The elongation rate of the first true leaf remained inhibited for 4 h after addition of polyethylene glycol 6000 (PEG; -0.5 MPa water potential), despite progressive osmotic adjustment in the growing leaf tissues. Thus, inhibition of leaf growth did not appear to be directly related to loss of leaf capacity to maintain osmotic potential gradients. Comparative cell-wall-extension capacities of immature (still expanding) leaf tissues were measured by creep extensiometry using whole plants. Reductions in irreversible (plastic) extension capacity (i.e. wall hardening) were detected minutes and hours after addition of PEG to the roots, by both in vivo and in vitro assay. The onset of the wall-hardening response could be detected by in vitro assay only 2 min after addition of PEG. Thus, initiation of wall hardening appeared to precede transcription-regulated responses. The inhibition of both leaf growth and wall-extension capacity was reversed by removal of PEG after 4 h. Moreover, wall hardening could be induced by other osmolytes (mannitol, NaCl). Thus, the leaf responses did not appear to be related to any specific (toxic) effect of PEG. We conclude that hardening of leaf cell walls is a primary event in the chain of growth regulatory responses to PEG-induced water deficits in maize. The signaling processes by which PEG, which is not expected to penetrate root cell walls or membranes, might cause cell-wall hardening in relatively distant leaves was also investigated. Plants with live or killed roots were exposed to PEG. The killed roots were presumed to be unable to produce hormonal or electrical signals in response to addition of PEG; however, inhibition of leaf elongation and hardening of leaf cell walls were detected with both live and killed roots. Thus, neither hormonal signaling nor signaling via induced changes in surface electrical potential were necessary, and hydraulic signals appeared to generate the leaf responses. PMID:12232175

Chazen, O.; Neumann, P. M.

1994-01-01

40

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

Microsoft Academic Search

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

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

2001-01-01

41

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

42

The rapid assembly of synaptic sites in photoreceptor terminals of the fly's optic lobe recovering from cold shock.  

PubMed

When a housefly, Musca domestica, is subject to cold exposure (0 degrees C for 24 hr), a number of obvious changes are seen in the first optic neuropil, or lamina, beneath the compound eye. In particular, the number of afferent photoreceptor synapses declines by about 30%. This loss is dramatically restored after warm recovery at 23 degrees C for 24 hr. Synapses disappear at an average rate of 2-3/hr during cold exposure and reappear at a maximal rate of more than 20/hr during the first 2 hr of warm recovery. Thereafter their number temporarily overshoots control values, to increase at 6 hr of warm recovery to 60% above their cold-exposed minimum. The number subsequently returns more or less to normal. These changes demonstrate the lability of synaptic sites under these conditions, with individual sites forming and disappearing rapidly. The changes also interrupt the close correlation between synaptic number and the surface area of the receptor terminal, a correlation that normally conserves synaptic spacing density. The density is preserved during cold exposure but increases during warm recovery at a time when the addition of newly formed synapses exceeds the slower increase in receptor terminal size. PMID:7708704

Brandstätter, J H; Meinertzhagen, I A

1995-03-28

43

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

USGS Publications Warehouse

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

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

1995-01-01

44

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

45

Suckling and cold stress rapidly and transiently increase TRH mRNA in the paraventricular nucleus.  

PubMed

Thyrotropin releasing hormone (TRH) is released from the median eminence in response to neural stimuli evoked by different physiologic conditions (i.e. cold stress or suckling). The paraventricular nucleus (PVN) synthesizes pro-TRH and responds to negative thyroid hormone feedback. With the aim of determining if TRH biosynthesis is regulated in coordination with its release, we quantified TRH mRNA levels in PVN and in preoptic area-anterior hypothalamus (POA-AH) of rats sacrificed at different times during cold (0.5, 1, 2 or 6 h) or suckling (15, 30 and 60 min) stimulus; TRH-like immunoreactivity (TRH-LI) in medial basal hypothalamus (MBH) and in POA-AH as well as corticosterone, triiodothyronine and prolactin levels in serum were also measured. Increases of serum hormones were observed in both paradigms as has been reported. MBH TRH-LI content decreased during suckling by 33% (p < 0.01) after 1 h, but did not change after cold stimulation. At short stimulation times, PVN TRH mRNA levels were 85% (30 min of suckling) and 97% (1 h in the cold) higher than their respective controls, decreasing to normal after 1-2 h. In the POA-AH, another TRH synthesizing region not involved in TRH hypophysiotropic function, a similar transient enhancement of TRH mRNA (146%) was observed only in cold stimulated animals after 30 min, consistent with its suggested role in thermogenesis. These results show a fast and transient response of TRH mRNA in PVN evoked by a neural stimulus. PMID:8264848

Uribe, R M; Redondo, J L; Charli, J L; Joseph-Bravo, P

1993-07-01

46

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

47

RAPID  

Cancer.gov

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

48

Calcium signaling mediates cold sensing in insect tissues  

PubMed Central

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

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

2013-01-01

49

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

2013-05-28

50

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

51

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

PubMed

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

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

2013-06-15

52

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

PubMed

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6??GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at ?sNN = 200??GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter. PMID:25014805

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

2014-06-27

53

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

54

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

55

Induction Hardening vs Conventional Hardening of a Heat Treatable Steel  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

56

A debris mechanism of cyclic strain hardening for F.C.C. metals  

Microsoft Academic Search

Prismatic dislocation loops (dislocation debris), formed by fatigue or cyclic straining, have been observed in a number of metals. To account for these observations a mechanism of cyclic strain hardening is proposed which depends on the ease of loop formation and the behaviour of the loops after they are formed. In the initial rapid hardening stage, the rate of cyclic

C. E. Feltner

1965-01-01

57

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

58

The cold resistance of Macaronesian Sempervivoideae  

Microsoft Academic Search

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

R. Lösch; L. Kappen

1981-01-01

59

System-Level Radiation Hardening  

NASA Technical Reports Server (NTRS)

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

Ladbury, Ray

2014-01-01

60

Plastic resin hardener poisoning  

MedlinePLUS

... lips, or tongue Throat swelling (which may also cause breathing difficulty) Loss of vision Heart and blood vessels: Low blood pressure, develops rapidly Collapse Stomach and intestines: Severe abdominal ...

61

An extension for the Ohno–Wang kinematic hardening rules to incorporate isotropic hardening  

Microsoft Academic Search

In this work, an extension of the well-known Ohno–Wang model to incorporate isotropic hardening is presented and discussed. The model is extended by taking into account isotropic hardening depending on accumulated plastic strain. It is assumed that isotropic hardening will be associated with kinematic hardening in the governing equations where activation of either isotropic or kinematic hardening is controlled through

Mohammad Abdel-Karim

2010-01-01

62

Case hardenability at high carbon levels  

NASA Astrophysics Data System (ADS)

Loss of hardenability in the case was thought to be responsible for a lower than specified hardness found on a large carburized bushing. Pseudo Jominy testing on several high hardenability carburizing grades confirmed that hardenability fade was present at carbon levels above 0.65% and particularly for those steels containing molybdenum. Analysis of previous work provided a formula for calculating Jominy hardenability at various carbon levels. Again the results confirmed that the loss of hardenability was more severe in steels containing molybdenum.

Walton, H. W.

1995-02-01

63

Strain Hardening in Polymer Glasses: Limitations of Network Models  

E-print Network

Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While traditional entropic network models can be fit to the total stress, their underlying assumptions are inconsistent with simulation results. There is a substantial energetic contribution to the stress that rises rapidly as segments between entanglements are pulled taut. The thermal component of stress is less sensitive to entanglements, mostly irreversible, and directly related to the rate of local plastic arrangements. Entangled and unentangled chains show the same strain hardening when plotted against the microscopic chain orientation rather than the macroscopic strain.

Robert S. Hoy; Mark O. Robbins

2007-05-29

64

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

65

Magnetic characterization of surface-hardened steel  

Microsoft Academic Search

Case depth measurements of surface-hardened steel parts are important for quality control. Here, the magnetic properties of two sets of carefully characterized 25-mm-diameter case-hardened steel rods were studied with the aim of developing new methods to evaluate the case depth nondestructively. Induction-hardened 4140 steel and carburized 8620 steel rods were studied. Each set contained control samples (heat-treated but not surface-hardened)

Chongxue Zhang; Nicola Bowler; Chester Lo

2009-01-01

66

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

Microsoft Academic Search

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 °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 °C. At room temperature or

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

2004-01-01

67

118 CASE HARDENING Routledge, London 2004  

E-print Network

commonly noted in warm deserts where little soil covers rock surfaces, case-hardened rocks occur in all Case hardening describes rocks with outer shells more resistant to erosion than interior material for DURICRUST, case hardening most frequently refers to differential weathering of the same rock type -- often

Dorn, Ron

68

Hardening process in ternary lead-antimony-tin alloys for battery grids  

NASA Astrophysics Data System (ADS)

It is known that lead-antimony alloys are very well hardened by continuous precipitation, whereas lead-tin alloys present a discontinuous precipitation with a weak hardening effect. In these binary alloys, there is precipitation of either antimony or tin. In ternary alloys, the compound SbSn can also precipitate. This study is focused on the type of precipitation, the nature and the morphology of the precipitated phases, and the intensity of hardening in ternary Pb?Sb?Sn alloys in relation to the composition of the alloys and the ternary diagram. To simulate the different processes of grid production, four states are studied, namely, as-cast product, rehomogenized, cold worked, cold worked and rehomogenized. The alloys contain up to 2.5 wt.% Sb and 2.5 wt.% Sn.

Hilger, J. P.

69

Low-temperature tolerance and cold hardening of cacti  

Microsoft Academic Search

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

Nobel

1982-01-01

70

Low temperature tolerance and cold hardening of cacti  

Microsoft Academic Search

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

Nobel

1982-01-01

71

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

PubMed Central

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

Rajashekar, C. B.; Lafta, A.

1996-01-01

72

Core Hardenability Calculations for Carburizing Steels  

Microsoft Academic Search

Analytical expressions are presented which allow the calculation of an ideal critical diameter (D1) and a Jominy end-quench hardenability curve for a steel from its chemical composition and prior austenite grain size. The\\u000a expressions are based on alloy hardenability factors in the literature and on the previously unpublished “hardness drop” method\\u000a of determiningD, from end-quench hardenability curves. Relationships defining Jominy

J. M. Tartaglia; G. T. Eldis

1984-01-01

73

Predicting the cold hardiness of willow stems using visible and near-infrared spectra and sugar concentrations  

Microsoft Academic Search

Closely related, fast-growing clones of willows from northern\\/continental and southern\\/maritime origins were assessed for their levels of cold hardiness. Assessments were made during active growth and, subsequently, during cold hardening at mean temperatures of 3°C (the COLD regime) and 8°C (the MILD regime). The onset of hardening was triggered simultaneously in all clones by administering a drastic day length reduction

Mattias Lennartsson; Erling Ögren

2003-01-01

74

A non-linear hardening model based on two coupled internal hardening variables: formulation and implementation  

E-print Network

An elasto-plasticity model with coupled hardening variables of strain type is presented. In the theoretical framework of generalized associativity, the formulation of this model is based on the introduction of two hardening variables with a coupled evolution. Even if the corresponding hardening rules are linear, the stress-strain hardening evolution is non-linear. The numerical implementation by a standard return mapping algorithm is discussed and some numerical simulations of cyclic behaviour in the univariate case are presented.

Point, Nelly

2009-01-01

75

Transmission and scanning electron microscope study on the secondary cyclic hardening behavior of interstitial-free steel  

SciTech Connect

Strain controlled fatigue experiment was employed to evaluate automotive grade interstitial-free ferrite steel. Hundreds of grains were examined by scanning electron microscope under electron channeling contrast image technique of backscattered electron image mode for comprehensive comparison of micrographs with those taken under transmission electron microscope. The cyclic stress responses clearly revealed that rapid hardening occurs at the early stage of cycling as a result of multiplication of dislocations to develop loop patches, dipolar walls and dislocation cells at various total strain amplitudes. After primary rapid hardening, stress responses varied from being saturated to further hardening according to dislocation structure evolution at various strain amplitudes. The fatigue failure was always accompanied with further hardening including secondary hardening. The corresponding dislocation structures with the three types of hardening behaviors are discussed. Once the secondary hardening starts, dislocation cells began to develop along grain boundaries in the low strain region and then extended into grain interiors as strain amplitudes increased and cycling went on. The secondary hardening rates were found to be directly proportional to their strain amplitudes.

Shih, Chia-Chang; Ho, New-Jin [Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Huang, Hsing-Lu, E-mail: hlhuang8423@gmail.com [Department of Mechanical Engineering, Chinese Military Academy, Kaohsiung, Taiwan (China)

2009-11-15

76

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.

1999-01-01

77

A non-linear hardening model based on two coupled internal hardening variables  

E-print Network

.erlicher@ing.unitn.it Abstract. An elasto-plasticity model with coupled hardening variables of strain type is presented, the stress-strain hardening evolution is non-linear. The numerical implementation by a standard return") where, in addition to the usual kinematic hardening internal variable, a second strain like internal

Paris-Sud XI, Université de

78

Common Cold  

MedlinePLUS

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

79

``Work-Hardenable'' Ductile Bulk Metallic Glass  

Microsoft Academic Search

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

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

2005-01-01

80

Effect of Thermoperiod and Photoperiod on Cold Tolerance of Spodoptera exigua (Lepidoptera: Noctuidae)  

Microsoft Academic Search

Beet armyworm, Spodoptera exigua (Hubner), is a freeze-susceptible and migratory species, but can overwinter in temperate areas without diapause. Most developmental stages reared under constant environments are able to induce a cold-hardening process in response to a brief exposure to cool temperature. In this study, we analyzed the effect of daily temperature and photoperiod cycles on the cold-hardening process. Rearing

Yonggyun Kim; Wonrae Song

2000-01-01

81

Cyber situational awareness and differential hardening  

NASA Astrophysics Data System (ADS)

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

Dwivedi, Anurag; Tebben, Dan

2012-06-01

82

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

83

Rapid onset of Little Ice Age summer cold in the northern North Atlantic derived from precisely dated ice cap records (Invited)  

NASA Astrophysics Data System (ADS)

Precise radiocarbon dates on dead vegetation emerging beneath retreating non-erosive ice caps in NE Arctic Canada define the onset of ice cap growth, and provide a Holocene context for 20th Century warming. Although most plateau ice caps melted during the Medieval Warm Period, a few that are now disappearing remained intact since at least 350 AD. Little Ice Age ice cap inception occurred in two pulses, centered on 1250-1300 AD and around 1450 AD, with ice caps remaining in an expanded state until the warming of the past few decades. Ice cap inception occurred simultaneously (±10 years) over a 200 m elevational range, suggesting an abrupt onset of Little Ice Age cold, rather than a slow cooling over many decades. Similarly, a 3000 year annually resolved lacustrine record of glacier power and a complementary independent proxy for landscape instability in the highlands of central Iceland show an initial jump in both glacier power and landscape instability between 1250 and 1300 AD, with a second step-increase around 1450 AD, and dramatic increases in both proxies around 1800 AD, retracting in the 20th Century. A sub-decadal record of hillslope stability and within-lake primary productivity in sediments from a low-elevation lake in northern Iceland shows parallel changes at similar times. Sea ice proxies and historical records document the first appearance of sea ice around Iceland following Medieval time about 1250 AD. The similarity in the onset and intensification of Little Ice Age cold-weather proxies across a wide region of the northern North Atlantic suggests at least a regional driver of abrupt climate change. The time intervals for which these abrupt changes occur coincide with the three most intense episodes of multiple explosive volcanic eruptions that introduced large volumes of sulfate aerosols into the stratosphere during the past millennium. Although the direct impacts of volcanic aerosols have a duration of only a few years, the memory stored by the cooled ocean surface waters allows a cumulative effect to have a longer-term impact. To explain the apparent irreversible shift to colder summers following volcanic eruptions requires additional strong positive feedbacks, most likely a consequence of expanded sea ice cover.

Miller, G. H.; Larsen, D.; Geirsdottir, A.; Refsnider, K. A.; Anderson, C.

2009-12-01

84

Structural influences on the work hardening behavior of aluminum  

SciTech Connect

Effects of various grain and subgrain morphologies on low temperature work hardening of pure Al is studied using tensile tests. Plotting the work hardening rate as a function of true stress, the work hardening is separable into two distinct regimes. Both regimes are approximated by a line {Theta} = {Theta}{sub 0} {minus} K{sub 2}{sigma}, where {Theta}{sub 0} is theoretical work hardening rate at zero stress and K{sub 2} is related to dynamic recovery rate. The first or early deformation regime exhibits greater values of {Theta}{sub 0} and K{sub 2} and can extend up to the first 10% strain of tensile deformation. This early deformation regime is contingent on the existence of a pre-existent dislocation substructure from previous straining. The {Theta}{sub 0} and K{sub 2} associated with the early deformation regime are dependent on the strength and orientation of the pre-existent dislocation substructure relative to the new strain path. At high enough temperatures, this pre-existent dislocation substructure is annealed out, resulting in the near elimination of the early deformation regime. In comparison, the latter regime is dominated by the initial grain and/or subgrain morphology and exhibit lower values of {Theta}{sub 0} and K{sub 2}. The actual value of K{sub 2} in the latter regime is strongly dependent on the existence of a subgrain morphology. Recrystallized or well-annealed microstructures exhibit greater values of K{sub 2} than microstructures that remain partially or fully unrecrystallized. The higher K{sub 2} value is indicative of a more rapid dynamic recovery rate and a greater degree of strain relaxation. The ability to achieve a more relaxed state produces a low-energy cellular dislocation substructure upon deformation. The introduction of subgrains hinders the evolution of a low-energy dislocation cell network, giving way to a more random distribution of the dislocation density.

Chu, D.

1994-12-01

85

How insects survive the cold: molecular mechanisms-a review.  

PubMed

Insects vary considerably in their ability to survive low temperatures. The tractability of these organisms to experimentation has lead to considerable physiology-based work investigating both the variability between species and the actual mechanisms themselves. This has highlighted a range of strategies including freeze tolerance, freeze avoidance, protective dehydration and rapid cold hardening, which are often associated with the production of specific chemicals such as antifreezes and polyol cryoprotectants. But we are still far from identifying the critical elements behind over-wintering success and how some species can regularly survive temperatures below -20 degrees C. Molecular biology is the most recent tool to be added to the insect physiologist's armoury. With the public availability of the genome sequence of model insects such as Drosophila and the production of custom-made molecular resources, such as EST libraries and microarrays, we are now in a position to start dissecting the molecular mechanisms behind some of these well-characterised physiological responses. This review aims to provide a state-of-the-art snapshot of the molecular work currently being conducted into insect cold tolerance and the very interesting preliminary results from such studies, which provide great promise for the future. PMID:18584182

Clark, Melody S; Worland, M Roger

2008-11-01

86

Laser Applications in Metal Surface Hardening  

E-print Network

CAST.IRON STEERING GEAR HOUSING FOCUSED BEAM ~-----' CQ,LASER SURFACE HARDENING Figure 4. Drawing shows basic arrangement for laser hard ning of internal surfaces. Paper Corrugating Rolls - Perhaps the largest p~rts to be regularly laser... hardened are 1250-kg rollS for corrugating kraft paper. The very abrasive paper caused excessive wear on the crowns of the fluteS and conventional furnace hardening of the entire roll waS found to be both energy wasteful and impractical. With the use...

Eckersley, J. S.

1982-01-01

87

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

Microsoft Academic Search

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

Akira Kawakami; Midori Yoshida

2005-01-01

88

Influence of laser surface hardening on the corrosion resistance of martensitic stainless steel  

Microsoft Academic Search

Martensitic high nitrogen stainless steels offer a combination of wear-, corrosion- and fatigue properties. But for some applications a higher surface hardness is required. A laser hardening with rapid heating (without smelting) and cooling (quenching) rates can improve the surface hardness with compressive residual stresses in the near surface layer. Yet, some cases of pitting corrosion in chloride media are

Y. Van Ingelgem; I. Vandendael; D. Van den Broek; A. Hubin; J. Vereecken

2007-01-01

89

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

90

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

91

Strain hardening, strain rate sensitivity, and ductility of nanostructured metals  

Microsoft Academic Search

This paper presents an overview of the strain hardening and strain rate hardening behavior of nanostructured and ultrafine-grained metals. The experimental findings obtained in our laboratory are summarized, with some recent data for ultrafine-grained Cu presented as a model case. Due to the diminishing strain hardening capacity and inadequate strain rate hardening, plastic instabilities in the form of inhomogeneous and

Y. M. Wang; E. Ma

2004-01-01

92

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

93

Laser Surface Hardening of AISI 1045 Steel  

NASA Astrophysics Data System (ADS)

The study investigates laser surface hardening in the AISI 1045 steel using two different types of industrial laser: a high-power diode laser (HPDL) and a CO2 laser, respectively. The effect of process parameters such as beam power, travel speed on structure, case depth, and microhardness was examined. In most cases, a heat-affected zone (HAZ) formed below the surface; a substantial increase in surface hardness was achieved. In addition, big differences were found between the hardened specimens after HPDL surface hardening and CO2 laser surface hardening. For HPDL, depths of the HAZ were almost equal in total HAZ o, without surface melting. For CO2 laser, the depths changed a lot in the HAZ, with surface melting in the center. To better understand the difference of laser hardening results when use these two types of laser, numerical (ANSYS) analysis of the heat conduction involved in the process was also studied. For HPDL method, a rectangular beam spot and uniform energy distribution across the spot were assumed, while for CO2 laser, a circular beam spot and Gaussian energy distribution were assumed. The results showed that the energy distribution variety altered the thermal cycles of the HAZ dramatically. The rectangular HPDL laser beam spot with uniform energy distribution is much more feasible for laser surface hardening.

Li, Ruifeng; Jin, Yajuan; Li, Zhuguo; Qi, Kai

2014-09-01

94

Core Hardenability Calculations for Carburizing Steels  

NASA Astrophysics Data System (ADS)

Analytical expressions are presented which allow the calculation of an ideal critical diameter (D1) and a Jominy end-quench hardenability curve for a steel from its chemical composition and prior austenite grain size. The expressions are based on alloy hardenability factors in the literature and on the previously unpublished “hardness drop” method of determining D, from end-quench hardenability curves. Relationships defining Jominy curve shape as a function of D I are developed. These differ from similar relationships previously published by recognizing that, for steels of low to medium hardenability, the microstructure contains significant amounts of non-martensitic transformation products even at the prescribed first position of hardness measurement on the end-quench hardenability bar, 1.59 mm (1/16 inch) from the quenched end. The analytical expressions presented are particularly well suited for the calculation of D I and end-quench hardenability curves for boron-free carburizing steels containing 0.15 to 0.25 pct carbon.

Tartaglia, J. M.; Eldis, G. T.

1984-06-01

95

Common cold  

MedlinePLUS

... and before eating and preparing food. Disinfect your environment. Clean commonly touched surfaces (such as sink handles, ... system work properly. Eat yogurt that contains "active cultures." These may help prevent colds. Probiotics may help ...

96

Phenomenological modeling of hardening and thermal recovery in metals  

NASA Technical Reports Server (NTRS)

Modeling of hardening and thermal recovery in metals is considered within the context of unified elastic-viscoplastic theories. Specifically, the choices of internal variables and hardening measures, and the resulting hardening response obtained by incorporating saturation-type evolution equations into two general forms of the flow law are examined. Based on the analytical considerations, a procedure for delineating directional and isotropic hardening from uniaxial hardening data has been developed for the Bodner-Partom model and applied to a nickel-base superalloy, B1900 + Hf. Predictions based on the directional hardening properties deduced from the monotonic loading data are shown to be in good agreement with results of cyclic tests.

Chan, K. S.; Lindholm, U. S.; Bodner, S. R.

1988-01-01

97

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

98

Project COLD.  

ERIC Educational Resources Information Center

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

Kazanjian, Wendy C.

1982-01-01

99

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.

100

Selective Hardening of NanoPLA Circuits Ilia Polian  

E-print Network

, the optimal strategy should probably combine some degree of hardware-level hardening to tune the error rate high error rates, implying the need for hardening techniques. We propose a fine-grained approach

Rao, Wenjing

101

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

102

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

103

Multiplicative AF kinematic hardening in plasticity  

Microsoft Academic Search

The basic innovation proposed in this work is to consider one of the two coefficients of the Armstrong and Frederick (AF) evolution equation for the back stress, function of another dimensionless second order internal variable evolving also according to an AF equation in what can be called a multiplicative AF kinematic hardening rule. Introducing the foregoing modification into some of

Yannis F. Dafalias; Kyriakos I. Kourousis; George J. Saridis

2008-01-01

104

Wellposedness of Kinematic Hardening Models in Elastoplasticity  

Microsoft Academic Search

We consider a certain type of rate independent elastoplastic constitutive laws for nonlinear kinematic hardening which include the models of Frederick-Armstrong, Bower and Mroz. We prove results concerning existence, uniqueness and continuous dependence for the stress-strain evolution considered as a function of time (but not of space). As an auxiliary result, we also prove a theorem concerning the Lipschitz continuity

Martin Brokate

105

Introduction 5 Mechanism of Irradiation Hardening 5  

E-print Network

activation decreases the force (F) necessary for the dislocations to pass over the obstacles is the Burgers' vector and a is constant. For the cutting or passing mechanism, * , - U g ^ . (S) In randomly ) of the obstacles, it can be concluded from equation S (1) that, for dispersed barrier hardening, ts a (C8)* (5

106

Modified kinematic hardening rules for simulations of ratchetting  

Microsoft Academic Search

In order to simulate multiaxial ratchetting, and as a preliminary step, common different variables introduced into the dynamic recovery term of recently developed hardening rules are presented and scrutinized in details. Subsequently, two modified kinematic hardening rules are formulated and presented. The proposed modified rules are based on the Ohno–Wang kinematic hardening rule in which accumulated plastic strain increment is

Mohammad Abdel-Karim

2009-01-01

107

Dislocation mechanisms, microstructures and hardening FROM DISLOCATION MECHANISMS TO DISLOCATION  

E-print Network

MICROSTRUCTURES AND STRAIN HARDENING L.P. Kubin and B. Devincre LEM, CNRS-ONERA, 29 Av. de la Division Leclerc BP in its absence. Then, strain hardening and dislocation patterning are related, since both derive from-based theories of strain hardening often involve phenomenological evolutionary laws for the spatially averaged

Devincre, Benoit

108

Theory of work-hardening applied to stages III and IV  

NASA Astrophysics Data System (ADS)

Stage IV has become the accepted name for that work-hardening stage within which large plastic strains can occur at a very low, virtually constant work-hardening rate, as exemplified by cold rolling and wire drawing. By contrast, in the preceding stage III, the work-hardening rate decreases sharply with strain, whereas in the still earlier stage II, the work-hardening rate is also almost constant but has a high value. The classical paper by Langford and Cohen on drawn iron wire is now recognized as one of the earliest studies of stage IV. Already in 1970, a detailed theoretical analysis of that work based on the mesh length theory was presented[2] which has stood the test of time, although in it the Langford and Cohen experiments were considered to represent stage II on account of the operation of similitude and the almost constant work-hardening rate. The present paper re-examines the 1970 theoretical interpretation in terms of stage IV behavior, which necessitates reinterpretation of stage III. Included in the present interpretation are more recent insights regarding dislocation behavior in so-called LEDS, low-energy dislocation structures. It is concluded that stages II and IV differ, because in stage II, cross slip is insignificant, while in stage IV, it is unlimited. Accordingly, cross slip is gradually established in the course of stage III. However, similitude appears to operate in all three stages. By extension of the argument regarding stages III and IV, it is seen that stages V and VI could follow, including similitude, through the establishment of climb.

Kuhlmann-Wilsdorf, D.; Hansen, N.

1989-11-01

109

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

110

HYPOTHERMIA Surviving the Cold  

E-print Network

weather, cold water, or an indoor freezer ­ is part of the job for many British Columbia workers. One with either artificial or natural cold is potentially at risk. Artificial cold is found in areas such as cold

Machel, Hans

111

Peak strength, strain hardening and dynamic restoration of A2 and M2 tool steels in hot deformation  

Microsoft Academic Search

Hot torsion continuous tests were performed on a cold work tool steel (A2) and a high speed steel (M2) in the temperature range of 900–1150°C at strain rates of 0.1, 1 and 4 s?1. The stress–strain curves, up to the peak, were analyzed for the dependence on temperature and strain rate, of strength, strain hardening, and dynamic recovery and recrystalization.

C. A. C. Imbert; H. J. McQueen

2001-01-01

112

Strain Hardening of Hadfield Manganese Steel  

Microsoft Academic Search

The plastic flow behavior of Hadfield manganese steel in uniaxial tension and compression is shown to be greatly influenced\\u000a by transformation plasticity phenomena. Changes in the stress-strain (???) curves with temperature correlate with the observed\\u000a extent of deformation twinning, consistent with a softening effect of twinning as a deformation mechanism and a hardening\\u000a effect of the twinned microstructure. The combined

P. H. Adler; G. B. Olson; W. S. Owen

1986-01-01

113

Automated air void analysis on hardened concrete  

Microsoft Academic Search

This paper presents the results of a European round robin test on air void analysis on hardened concrete (SMT-EC-research project — Contract No. SMT4-CT95-2006). Thirteen laboratories in Europe from seven countries participated in the intercomparison test of which seven used a manual method and six an automated measurement system. The results indicate that the results obtained with measuring methods using

J. Elsen

2001-01-01

114

Pulsed laser surface hardening of ferrous alloys.  

SciTech Connect

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

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

1999-09-30

115

Cold Stowage Flight Systems  

NASA Technical Reports Server (NTRS)

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

Campana, Sharon

2010-01-01

116

Cold Stowage Flight Systems  

NASA Technical Reports Server (NTRS)

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

Campana, Sharon E.; Melendez, David T.

2011-01-01

117

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

Microsoft Academic Search

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

J. Beswick

1984-01-01

118

Magnetic hardening induced by nonmagnetic organic molecules.  

PubMed

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. PMID:25166694

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

2013-09-01

119

Technology Developments in Radiation-Hardened Electronics for Space Environments  

NASA Technical Reports Server (NTRS)

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

Keys, Andrew S.; Howell, Joe T.

2008-01-01

120

Extraordinary strain hardening by gradient structure XiaoLei Wua,1  

E-print Network

Extraordinary strain hardening by gradient structure XiaoLei Wua,1 , Ping Jianga , Liu Chena in engineering materials such as metals renders a unique extra strain hardening, which leads to high ductility in an extra strain hardening and an obvious strain hardening rate up-turn. Such extraordinary strain hardening

Zhu, Yuntian T.

121

Protective coatings of metal surfaces by cold plasma treatment  

NASA Technical Reports Server (NTRS)

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

Manory, R.; Grill, A.

1985-01-01

122

Cold Atoms  

NASA Astrophysics Data System (ADS)

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

Bellac, Michel Le

2014-11-01

123

A neutron radiation-hardened superluminescent diode  

NASA Astrophysics Data System (ADS)

We present a novel superluminescent diode (SLD) with high optical performances for hardened neutron irradiation. The degradation of the light output from the SLDs is caused by a reduction of the minority carrier lifetime resulting from displacement damage after high-energy neutron irradiation. The SLDs with a higher pre-irradiation light output will be less sensitive to radiation. We have selected an InGaAsP/InP multi-quantum well (MQW) as the active region structure for its performance, its high optical gain and minute active region. Graded-index separate-confinement-heterostructure (GRIN-SCH) has been applied for the waveguide structure. A specific absorbing region and anti-reflective coatings have been designed and optimized. Moreover, the radiation test results indicate that the SLD with an InGaAsP/InP MQW structure has better neutron hardening ability than the SLD with DH structures after a 6 × 1013 - 1 × 1014 n/cm2 1 MeV neutron irradiation.

Jian, Jiao; Manqing, Tan; Miao, Zhao; Jinlong, Chang

2012-09-01

124

Hardened Client Platforms for Secure Internet Banking  

NASA Astrophysics Data System (ADS)

We review the security of e-banking platforms with particular attention to the exploitable attack vectors of three main attack categories: Man-in-the-Middle, Man-in-the-PC and Man-in-the-Browser. It will be shown that the most serious threats come from combination attacks capable of hacking any transaction without the need to control the authentication process. Using this approach, the security of any authentication system can be bypassed, including those using SecureID Tokens, OTP Tokens, Biometric Sensors and Smart Cards. We will describe and compare two recently proposed e-banking platforms, the ZTIC and the USPD, both of which are based on the use of dedicated client devices, but with diverging approaches with respect to the need of hardening the Web client application. It will be shown that the use of a Hardened Browser (or H-Browser) component is critical to force attackers to employ complex and expensive techniques and to reduce the strength and variety of social engineering attacks down to physiological fraud levels.

Ronchi, C.; Zakhidov, S.

125

Effect of work hardening on dynamic friction  

NASA Astrophysics Data System (ADS)

We have studied dynamic friction by impacting a copper plate onto a target consisting of a tapered, annealed, aluminium alloy plug mounted into a matching hole in a stainless steel outer sheath. The velocity of the back surface of the plug was measured using velocity interferometry. Unfortunately it was found that apparently identical configurations gave significantly different velocity profiles. Therefore a series of experiments were conducted in which the manufacturing tolerances were tightened and the assembly procedure was more carefully controlled than previously. Five experiments have been performed at the same impact velocity, (300m/s). Comparing the recent results with those fired previously it has become apparent that work hardening processes in the aluminium alloy near the sliding interface play an important role in the development of frictional forces. It is thought that work hardening generated at those regions of the cone surface in contact with the outer steel component during the assembly process leads to localised shear and, therefore, low friction when the system is loaded dynamically. By contrast those regions of the aluminium surface which remain soft give high friction following dynamic loading. We believe these effects explain the variability in the observed velocity traces.

Winter, Ron; Stirk, S. M.; Collinson, Mark Alistair

2012-03-01

126

Cost-Effective Radiation Hardening Technique for Combinational Logic  

E-print Network

Cost-Effective Radiation Hardening Technique for Combinational Logic Quming Zhou and Kartik, kmram}@rice.edu Abstract-- A radiation hardening technique for combinational logic circuits is described-effective tradeoffs that can be achieved. I. INTRODUCTION When high-energy neutrons (present in terrestrial cosmic

Mohanram, Kartik

127

ORIGINAL PAPER Growth and frost hardening of European aspen  

E-print Network

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

Paris-Sud XI, Université de

128

Microstructural Evolution and Age Hardening in Aluminium Alloys  

Microsoft Academic Search

This paper examines the microstructural evolution in selected aluminium alloys based on commercial age hardenable 2000, 6000, and 7000 series alloys. Atom probe field-ion microscopy and transmission electron microscopy have been used to examine the effects of microalloying and the origins of hardening. The combined application of these techniques is particularly important in the study of nanoscale precipitation processes. It

S. P. Ringer; K. Hono

2000-01-01

129

An analysis of induction hardening of ferritic ductile iron  

NASA Astrophysics Data System (ADS)

Achievements of the induction hardening of ferritic ductile iron were investigated. Ductile iron is not advisable for use in induction hardening because of the small carbon content in the metal matrix of ferritic ductile iron. The carbon content in the metal matrix of ductile iron can be increased by additional preparation of metal matrix before final induction heat hardening. Wear resistance of the induction hardened ferritic ductile iron can increase as result of increased carbon content of the metal matrix and higher hardness after induction hardening. Some heat pretreatments for metal matrix preparation were applied before the induction hardening of ferritic ductile iron. The process parameters of the induction hardening heat pretreatment were analyzed and optimized. According to recommended elemental composition of ferritic ductile iron and required mechanical properties, the process parameters of the investigated induction heat pretreatment were optimized. The efficiency of pretreatment processes of induction hardening was analyzed. Applicability and manufacture ability of engineering components by proposed heat pretreatments were investigated. The limitations of the investigated heat pretreatment applications were estimated by the comparison of mechanical properties of heat-treated specimens.

Smoljan, Božo; Cajner, Franjo; Landek, Darko

2002-06-01

130

Kinematic hardening model suitable for ratchetting with steady-state  

Microsoft Academic Search

A new kinematic hardening model useful for simulating the steady-state in ratchetting is developed within the framework of the strain hardening and dynamic recovery format. The model is formulated to have two kinds of dynamic recovery terms, which operate at all times and only in a critical state, respectively. The model is examined on the basis of nonproportional experiments of

M. Abdel-Karim; N. Ohno

2000-01-01

131

Kinematic hardening rules for modeling uniaxial and multiaxial ratcheting  

Microsoft Academic Search

Ratcheting, which is the strain accumulation observed under the unsymmetrical stress controlled loading and non-proportional loadings, is modeled using the simplified viscoplasticity theory based on overstress (VBO). The influences of kinematic hardening laws on the uniaxial and multiaxial non-proportional ratcheting behavior of CS 1026 carbon steel have been investigated. The following kinematic hardening rules have been considered: the classical kinematic

Ozgen U. Colak

2008-01-01

132

The restricted influence of kinematic hardening on shakedown loads  

Microsoft Academic Search

Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown

Manfred Staat; Michael Heitzer

2002-01-01

133

The Role of Collinear Interaction in Dislocation-Induced Hardening  

E-print Network

-centered cubic crystals. The results contradict the traditional assumption that strain hardening is governedThe Role of Collinear Interaction in Dislocation-Induced Hardening R. Madec,1 * B. Devincre,1 L in a crystal and induce long-range stress and strain fields. Under an externally applied stress, dislocations

Devincre, Benoit

134

Cold hardiness in relation to trace metal stress in the freeze-avoiding beetle Tenebrio molitor  

Microsoft Academic Search

The antifreeze proteins (AFPs) are a family of proteins characterised by their ability to inhibit the growth of ice. These proteins have evolved as a protection against lethal freezing in freeze avoiding species. Metal stress has been shown to reduce the cold hardening in invertebrates, but no study has investigated how this type of stress affects the production of AFPs.

Sindre A. Pedersen; Erlend Kristiansen; Bjørn H. Hansen; Rolf A. Andersen; Karl E. Zachariassen

2006-01-01

135

The effect of nitrogen on the cold forging properties of 1020 steel  

Microsoft Academic Search

We have studied the effect of nitrogen on the cold forging properties of a low carbon steel as a function of temperature. Five AISI 1020 steels with nitrogen contents from 12 to 180ppm were examined by tensile testing from 25 to 371°C. Yield strength, tensile elongation (ductility), ultimate tensile strength (UTS), strain hardening exponents and strength coefficients were determined. The

T. J. Douthit; C. J. Van Tyne

2005-01-01

136

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

137

A review of the stages of work hardening  

SciTech Connect

Stages of work hardening are reviewed with emphasis on links between each stage. Simple quantitative descriptions are given for each stage. Similarities between stage I, easy glide, and stage IV, large strain hardening, are pointed out both in terms of magnitude of the hardening rate and of the underlying mechanism of dislocation debris accumulation. Stage II is described as an athermal hardening stage that occurs when statistical variations in the dislocation ``forest`` lead to geometrical storage of dislocations. The steadily decreasing hardening rate observed in stage III is characterized by the increasing rate of loss of dislocation density due to dynamic recovery. Stage III appears to have an asymptote to a saturation stress which is determined by the characteristics of the dislocation tangles, or cell walls. The imperfect nature of the dynamic recovery process, however, leads to the accumulation of dislocation debris and this, by analogy with stage 1, causes the apparent saturation stress to rise, thus causing stage IV.

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

1993-07-01

138

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

139

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.

2007-02-01

140

Assessment of bart fire-hardening programs. Final report may-sep 82  

SciTech Connect

This report presents the results of an assessment of the Bay Area Rapid Transit District (BART) vehicle fire hardening. The report assesses the overall effort to improve the fire safety of the current BART vehicles through the removal of prospective ignition sources, the substitution of more fire-resistant materials, the addition of a special fire-resistant coating on the under surface of the vehicle floor, and the placement of fire stops at strategic places in the walls and ceilings. Specifically, this assessment responds to ten concerns on these improvements that were expressed by the California Public Utilities Commission.

Hathaway, W.T.; Litant, I.

1982-09-01

141

Porosity and mechanically optimized PLGA based in situ hardening systems.  

PubMed

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

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

2012-11-01

142

Rapid tooling  

Microsoft Academic Search

Rapid tooling can be seen as the second wave in rapid prototyping because, with rapid tooling, the production process can be prototyped instead of the final product. This article discusses and compares several existing processes available for rapid tooling. For each process, the product size and the number of shots is estimated. Since this text was part of the Internet

Eric Radstok

1999-01-01

143

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

144

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

145

Surface hardening of Ti alloys by gas-phase nitridation: Kinetic control of the nitrogen surface activity  

Microsoft Academic Search

A new concept for surface hardening of titanium alloys has been developed and successfully applied to Ti-6Al-4V alloys: gas-phase\\u000a nitridation under kinetic control of the nitrogen activity. This method avoids the formation of detrimental second-phase nitrides by nitriding under a very low nitrogen activity, combined\\u000a with rapid diffusion of nitrogen into the specimen. The surface hardness of the Ti-6Al-4V alloy

L. Liu; F. Ernst; G. M. Michal; A. H. Heuer

2005-01-01

146

Liquation Microfissuring in the Weld Heat-Affected Zone of an Overaged Precipitation-Hardened Nickel-Base Superalloy  

Microsoft Academic Search

The effect of preweld overaging heat treatment on the microstructural response in the heat-affected zone (HAZ) of a precipitation-hardened\\u000a nickel-base superalloy INCONEL 738LC subjected to the welding thermal cycle (i.e., rapid) was investigated. The overaging heat treatment resulted in the formation of an interfacial microconstituent containing\\u000a M23X6 particles and coarsening of primary and secondary ?? precipitates. The HAZ microstructures around

O. A. Ojo; M. C. Chaturvedi

2007-01-01

147

Liquation Microfissuring in the Weld Heat-Affected Zone of an Overaged Precipitation-Hardened Nickel-Base Superalloy  

Microsoft Academic Search

The effect of preweld overaging heat treatment on the microstructural response in the heat-affected zone (HAZ) of a precipitation-hardened nickel-base superalloy INCONEL 738LC subjected to the welding thermal cycle ( i.e., rapid) was investigated. The overaging heat treatment resulted in the formation of an interfacial microconstituent containing M23X6 particles and coarsening of primary and secondary gamma' precipitates. The HAZ microstructures

O. A. Ojo; M. C. Chaturvedi

2007-01-01

148

Observation of Reverse Transformation of ?-?-? in ultrafine - grained Fe-Ni-Mn Age Hardenable Martensitic Steel  

NASA Astrophysics Data System (ADS)

Fe-10Ni-7Mn (wt %) martensitic steel is a member of ultrahigh strength steels. This alloy is ductile in the solution annealed condition and shows good age hardenability but it suffers from severe embrittlement after aging. Discontinuous coarsening of grain boundary precipitates was found as the main source of embrittlement. In this paper the effect of cold rolling on the mechanical properties and phase stability of Fe-10Ni-7Mn steel was investigated. Cold rolling for 20%, 60%, and 90% were carried out on a solution annealed material with subsequent aging at 753 K. X- ray diffraction results and transmission electron microscopy (TEM) micrographs showed the presence of austenite in severely cold rolled samples. This austenite is likely formed as a result of deformation, and it seems to originate from a reverse transformation from bcc-martensite to hcp-martensite to austenite, stimulated by increasing the amount of deformation. This transformation improves the mechanical properties in this steel while in as annealed and aged condition it has premature fracture and zero ductility.

Ghasemi-Nanesa, H.; Nili Ahmadabadi, M.; Shirazi, H.; Hossein Nedjad, S.

149

Cold Stress and the Cold Pressor Test  

ERIC Educational Resources Information Center

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

Silverthorn, Dee U.; Michael, Joel

2013-01-01

150

Stress corrosion cracking evaluation of precipitation-hardening stainless steel  

NASA Technical Reports Server (NTRS)

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

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

1970-01-01

151

Cold and Cough Medicines  

MedlinePLUS

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

152

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

Microsoft Academic Search

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

Ivaylo N. Vladimirov; Stefanie Reese

2007-01-01

153

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

Microsoft Academic Search

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,

Zhou Wang; Chuanhai Jiang; Xiaoyan Gan; Yanhua Chen

2010-01-01

154

On flow and work hardening expression correlations in metallic single crystal plasticity  

E-print Network

plastic flow (Schmid law, rate dependent approach, percolation model) and work hardening (strain hardening comes out that, within the Schmid law frame, the strain hardening law is the limit case383 On flow and work hardening expression correlations in metallic single crystal plasticity P

Paris-Sud XI, Université de

155

Cold dark matter heats up.  

PubMed

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

Pontzen, Andrew; Governato, Fabio

2014-02-13

156

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

157

Finite deformation plasticity and viscoplasticity laws exhibiting nonlinear hardening rules  

Microsoft Academic Search

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

E. Diegele; W. Jansohn; Ch. Tsakmakis

2000-01-01

158

Modified kinematic hardening rule for multiaxial ratcheting prediction  

Microsoft Academic Search

A modified kinematic hardening rule is proposed in which one biaxial loading dependent parameter? 0 connecting the radial evanescence term ((? :n)ndp) in the Burlet-Cailletaud model with the dynamic recovery term of Ohno-Wang kinematic hardening rule is introduced into the framework of the Ohno-Wang model. Compared with multiaxial ratcheting experimental data obtained on 1Cr18Ni9Ti stainless steel in the paper and

X. Chen; R. Jiao

2003-01-01

159

Modified kinematic hardening rule for multiaxial ratcheting prediction  

Microsoft Academic Search

A modified kinematic hardening rule is proposed in which one biaxial loading dependent parameter ?? connecting the radial evanescence term [(?:n)ndp] in the Burlet–Cailletaud model with the dynamic recovery term of Ohno–Wang kinematic hardening rule is introduced into the framework of the Ohno–Wang model. Compared with multiaxial ratcheting experimental data obtained on 1Cr18Ni9Ti stainless steel in the paper and CS1026

X. Chen; R. Jiao

2004-01-01

160

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

161

Cold fusion: Alchemist's dream  

Microsoft Academic Search

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;

E. D. Clayton

1989-01-01

162

Exercising in Cold Weather  

MedlinePLUS

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

163

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

E-print Network

callus cells, strands were present in leaf epidermal cells. Finally, the movement of attached credit for the discovery and the filaments were subsequently called Hechtian strands. Several authors, as seen by transmission electron microscopy using phosphotungstic acid (Sitte, 1963; Oparka et al., 1994

Swartzlander Jr., Grover A.

164

Cold Fronts in Cold Dark Matter Clusters  

NASA Astrophysics Data System (ADS)

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters. These features, called cold fronts, are characterized by an increase in surface brightness by a factor >~2 over 10-50 kpc accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM) if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging subcluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the amplitude of gas density and temperature gradients across the front. Our results indicate that cold fronts are nonequilibrium transient phenomena and can be observed for a period of less than a billion years. We show that the velocity and density fields of gas surrounding the cold front can be very irregular, which would complicate analyses aiming to put constraints on the physical conditions of the ICM in the vicinity of the front.

Nagai, Daisuke; Kravtsov, Andrey V.

2003-04-01

165

Magnetic hysteresis behavior and microstructure of severely cold-worked and aged Co-Fe-Nb alloy  

Microsoft Academic Search

The magnetic hysteresis behavior of severely cold-worked and aged 85Co-12Fe-3Nb alloy was studied in relation to the microstructure. Magnetic hardening of the alloy can be attributed to the pinning of the domain wall by quasispherical Co3Nb precipitates. Alloys cold worked to 97.8% reduction in area and aged at 700, 800, and 900 °C showed the hysteresis behavior characteristic of inhomogeneous

Yuichi Suzuki; Masato Sagawa; Masanori Okada; Zenzo Henmi

1979-01-01

166

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

167

Cold nuclear matter effects on J/? yields as a function of rapidity and nuclear geometry in d+A collisions at sqrt[s(NN)]=200??GeV.  

PubMed

We present measurements of J/? yields in d+Au collisions at sqrt[s(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/? 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. PMID:22107186

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; Csörgo, 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; 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; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slune?ka, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sziklai, J; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomita, Y; Torii, H; Towell, R S

2011-09-30

168

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

NASA Astrophysics Data System (ADS)

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

Mohan, Nisha

169

Facts about the Common Cold  

MedlinePLUS

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

170

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

Microsoft Academic Search

We present measurements of J\\/psi yields in d+Au collisions at sNN=200GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J\\/psi rapidity (-2.2

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

2011-01-01

171

Nanoscale Strain-Hardening of Keratin Fibres  

PubMed Central

Mammalian appendages such as hair, quill and wool have a unique structure composed of a cuticle, a cortex and a medulla. The cortex, responsible for the mechanical properties of the fibers, is an assemblage of spindle-shaped keratinized cells bound together by a lipid/protein sandwich called the cell membrane complex. Each cell is itself an assembly of macrofibrils around 300 nm in diameter that are paracrystalline arrays of keratin intermediate filaments embedded in a sulfur-rich protein matrix. Each macrofibril is also attached to its neighbors by a cell membrane complex. In this study, we combined atomic force microscopy based nano-indentation with peak-force imaging to study the nanomechanical properties of macrofibrils perpendicular to their axis. For indentation depths in the 200 to 500 nm range we observed a decrease of the dynamic elastic modulus at 1 Hz with increasing depth. This yielded an estimate of 1.6GPa for the lateral modulus at 1 Hz of porcupine quill’s macrofibrils. Using the same data we also estimated the dynamic elastic modulus at 1 Hz of the cell membrane complex surrounding each macrofibril, i.e., 13GPa. A similar estimate was obtained independently through elastic maps of the macrofibrils surface obtained in peak-force mode at 1 kHz. Furthermore, the macrofibrillar texture of the cortical cells was clearly identified on the elasticity maps, with the boundaries between macrofibrils being 40–50% stiffer than the macrofibrils themselves. Elasticity maps after indentation also revealed a local increase in dynamic elastic modulus over time indicative of a relaxation induced strain hardening that could be explained in term of a ?-helix to ?-sheet transition within the macrofibrils. PMID:22848616

Fortier, Patrick; Suei, Sandy; Kreplak, Laurent

2012-01-01

172

Nanoscale strain-hardening of keratin fibres.  

PubMed

Mammalian appendages such as hair, quill and wool have a unique structure composed of a cuticle, a cortex and a medulla. The cortex, responsible for the mechanical properties of the fibers, is an assemblage of spindle-shaped keratinized cells bound together by a lipid/protein sandwich called the cell membrane complex. Each cell is itself an assembly of macrofibrils around 300 nm in diameter that are paracrystalline arrays of keratin intermediate filaments embedded in a sulfur-rich protein matrix. Each macrofibril is also attached to its neighbors by a cell membrane complex. In this study, we combined atomic force microscopy based nano-indentation with peak-force imaging to study the nanomechanical properties of macrofibrils perpendicular to their axis. For indentation depths in the 200 to 500 nm range we observed a decrease of the dynamic elastic modulus at 1 Hz with increasing depth. This yielded an estimate of 1.6GPa for the lateral modulus at 1 Hz of porcupine quill's macrofibrils. Using the same data we also estimated the dynamic elastic modulus at 1 Hz of the cell membrane complex surrounding each macrofibril, i.e., 13GPa. A similar estimate was obtained independently through elastic maps of the macrofibrils surface obtained in peak-force mode at 1 kHz. Furthermore, the macrofibrillar texture of the cortical cells was clearly identified on the elasticity maps, with the boundaries between macrofibrils being 40-50% stiffer than the macrofibrils themselves. Elasticity maps after indentation also revealed a local increase in dynamic elastic modulus over time indicative of a relaxation induced strain hardening that could be explained in term of a ?-helix to ?-sheet transition within the macrofibrils. PMID:22848616

Fortier, Patrick; Suei, Sandy; Kreplak, Laurent

2012-01-01

173

High-Performance, Radiation-Hardened Electronics for Space Environments  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

174

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

175

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

176

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

177

Evidence from the NorthGRIP ice core for rapid development of playa areas from Western Chinese lakes reinforced by the 8.2 ka BP Holocene cold event  

NASA Astrophysics Data System (ADS)

Analysis of soluble ions in the NorthGRIP ice core has revealed a lithium anomaly in the aerosol dust material around the 8.2 ka BP event. This anomaly is characterized by a sudden increase in soluble lithium concentrations, still increasing over at least one century, and reaching up to two orders of magnitude higher concentrations than prior to the event. Geochemical properties of lithium suggest that this lithium-anomaly is an effect of rock - water interactions in the dust source area. Mineral dust in Greenland ice cores has provenance distinctly in Western and North-Western Chinese desert areas. High abundances of lithium in this area are found in the Chaerhan lake playa located in the Qaidam basin north of the Tibetan plateau. During early Pleistocene the Qaidam basin was occupied by the mega Chaerhan Lake, which was steadily shallowing during Late Pleistocene. Lake records have previously shown that around 8 ka BP, the lake turned into a playa. The lithium anomaly in the NorthGRIP ice core around 8.2 ka BP is likely to be associated with the transformation of the Chaerhan salt lake into a playa, exposing large areas of clayish lake sediments to the atmosphere, and indicating that the transformation of the lake occurred very rapidly. A weakening of the Asian monsoons during the 8.2 ka BP indicated by monsoonal proxies, suggests that the 8.2 ka BP event effected a retreat of the range of monsoonal precipitation from inland Western China. Reduced precipitation combined with high evaporation during the Holocene optimum could have resulted in rapid changes in Western Chinese desert areas from relatively wet into very dry conditions.

Clausen, H. B.; Siggaard-Andersen, M.

2005-12-01

178

Cold fusion, Alchemist's dream  

SciTech Connect

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

Clayton, E.D.

1989-09-01

179

A dnaN plasmid shuffle strain for rapid in vivo analysis of mutant Escherichia coli ? clamps provides insight into the role of clamp in umuDC-mediated cold sensitivity.  

PubMed

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

Babu, Vignesh M P; Sutton, Mark D

2014-01-01

180

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

181

Method and apparatus for welding precipitation hardenable materials  

DOEpatents

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

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

1994-06-28

182

The effect of niobium on the hardenability of microalloyed austenite  

NASA Astrophysics Data System (ADS)

The powerful effect that varying the extent of niobium-carbide dissolution has on the “hardenability” of microalloyed austenite is demonstrated using dilatometric measurement of the critical cooling rate required to from microstructures containing >95 Pct martensite. The results can be rationalized on the hypothesis that the hardenability of austenite is enhanced by niobium in solid solution, possibly by its segregation to austenite grain boundaries, but is decreased by precipitation of niobium-carbide particles. This effect appears analogous to that of boron in steels and is found to be independent of variations in the austenite grain size.

Fossaert, C.; Rees, G.; Maurickx, T.; Bhadeshia, H. K. D. H.

1995-01-01

183

Numerical analysis and optimal control of induction heating hardening  

NASA Astrophysics Data System (ADS)

This work is presented a mathematical model of the electromagnetic and heating processes in cylindrical body placed in the inductor and is developed controller, which provide mode of metal hardening. Here, is a simplified version of the problem we shall try to prescribe a given isothermal line to be distinguished at a given final time. The mathematical model includes solving the electromagnetic and heating problems. With the finite elements method the mathematical model is lead to the linear system ODEs. This allows to be used the predictive control system theory and develop a controller which provides a mode of metal hardening.

Gilev, Bogdan; Yonchev, Andrey; Penev, Dimitar

2010-10-01

184

Fully-depleted submicron SOI for radiation hardened applications  

SciTech Connect

Using fully-depleted technology, the Loral 256K SOI SRAM has demonstrated under worst case SEU and prompt dose testing an LET threshold of at least 80 MeV*cm[sup 2]/mg, and a prompt dose rate upset level of greater then 4E10 rad(Si)/s, respectively, without design hardening. Total dose testing on transistors fabricated on enhanced bond and etchback SOI substrates indicates over 100 krad(Si) capability. Together, these results represent the first description of a fully depleted SOI technology for all radiation-hardened applications except extreme total dose.

Brady, F.T.; Scott, T.; Brown, R.; Damato, J.; Haddad, N.F. (Loral Federal Systems, Manassas, VA (United States))

1994-12-01

185

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

NASA Astrophysics Data System (ADS)

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

Deville, G. J.

186

Strain hardening in salt results of the SALMON experiment  

SciTech Connect

Salmon was a nuclear explosion in the Tatum salt dome, near Hattiesburg, Mississippi, that took, place on October 22, 1964. Computational attempts to simulate the experimental results had been largely unsuccessful. This paper reports that recent calculations suggest that the reason is that the salt yield strength is extremely sensitive to strain hardening. The hardening effect had not been observed in laboratory-scale measurements, which were not made at small enough strain levels and may not have been representative of in-situ pore-fluid pressure.

Glenn, L.A. (Lawrence Livermore National Lab., CA (USA))

1990-06-01

187

Strain hardening in salt--results of the SALMON experiment  

SciTech Connect

SALMON was a nuclear explosion in the Tatum salt dome, near Hattiesburg, Mississippi, that took place on October 22, 1964. Computational attempts to simulate the experimental results had been largely unsuccessful. Recent calculations suggest that the reason is that the salt yield strength is extremely sensitive to strain hardening. The hardening effect had not been observed in laboratory-scale measurements, which were not made at small enough strain levels and may not have been representative of in situ pore-fluid pressure. 10 refs., 7 figs.

Glenn, L.A. (Lawrence Livermore National Lab., CA (USA))

1989-06-02

188

Laser hardening techniques on steam turbine blade and application  

NASA Astrophysics Data System (ADS)

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

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

189

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

PubMed

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

Park, Jung-Hui; Lee, Eun-Jung; Knowles, Jonathan C; Kim, Hae-Won

2014-03-01

190

Cold Air Damming  

NSDL National Science Digital Library

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

Comet

2001-06-18

191

Cold Sores (HSV-1)  

MedlinePLUS

... sunlight, cold weather, hormone changes in menstruation or pregnancy, tooth extractions, and certain foods and drugs. In a lot of people, the cause is unpredictable. Here's how a cold sore develops: The herpes simplex virus-1, which has been lying dormant in ...

192

Environmental control of cold hardiness in woody plants.  

PubMed

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

Irving, R M; Lanphear, F O

1967-09-01

193

Analysis of cold and hot isostatic compaction of spherical particles  

SciTech Connect

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

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

1996-09-01

194

The stress-hydrogen corroding and protecting with the surface hardening  

SciTech Connect

The states of the stress with the surface hardening are analyzed, the related experimential formulas on the change of the stress-temperature and the stress-depth hardened curves are set up, the protecting measures are discussed.

Qinghua, Z. [Wuhan Institute of Textile Science and Technology, Hubei (China)

1996-12-31

195

Characteristic features of the hot and cold pressing of powder preforms  

Microsoft Academic Search

1.It is shown that high-density molybdenum with a fine-grained structure can be produced by cold and hot pressing under ultrahigh pressure. The optimum UHP pressing pressure has been established.2.As a result of microhardness and x-ray line breadth measurements, it is demonstrated that pressing induces strain hardening in compacted Mo powder, the resultant dense material being one and a half times

V. E. Baturin; Yu. D. Klebanov; B. V. Rozanov; V. N. Sumarokov

1973-01-01

196

Effect of cold-work and annealing on the anelasticity of L62 [62% Cu] brass  

Microsoft Academic Search

1.Reheating of work-hardened brass L62 at 200–250° C increases the elastic limit and reduces (down to 1\\/16) the direct elastic after-effect while increasing its reversibility.2.Contrary to the behavior of the elastic limit and elastic after-effect, the tensile strength, elongation at fracture, and hardness of heavily cold worked (up to 58%) L62 brass, do not have significant extreme values affected by

S. O. Tsobkallo; Z. A. Vashchenko

1959-01-01

197

Phonon Hardening due to Photo-excited Carriers in Graphene  

NASA Astrophysics Data System (ADS)

We observed the hardening of E2g phonons due to photoexcited carriers in Raman spectroscopic measurements of graphene. As the excitation laser intensity is increased, the Raman G band of graphene blushifts and becomes narrower. This shift and line-narrowing is interpreted in terms of the Kohn anomaly suppression due to photoexcited carriers.

Yoon, Duhee; Moon, Hyerim; Woo, Seoungwoo; Cheong, Hyeonsik; Son, Young-Woo

2011-12-01

198

Mathematical Analysis of Thermoplasticity with Linear Kinematic Hardening  

E-print Network

Mathematical Analysis of Thermoplasticity with Linear Kinematic Hardening Krzysztof Che lmi#19;nski #3;y & Reinhard Racke z Abstract We study thermoplasticity with the Prandtl-Reuss ow rule approximation, converges to a global in time solution of the (modi#12;ed) system of thermoplasticity. AMS classi

Racke, Reinhard

199

Performance comparison of radiation-hardened layout techniques  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

200

SEU-hardened storage cell validation using a pulsed laser  

Microsoft Academic Search

Laser tests performed on a prototype chip to validate new SEU-hardened storage cell designs revealed unexpected latch-up and single-event upset phenomena. The investigations that identified their location show the existence of a topology-dependent dual node upset mechanism. Design solutions are suggested to avoid its occurrence

R. Velazco; T. Calin; M. Nicolaidis; S. C. Moss; S. D. LaLumondiere; V. T. Tran; R. Koga

1996-01-01

201

Microstructure and microanalysis of hardened ordinary Portland cement pastes  

Microsoft Academic Search

Hardened ordinary Portland cement pastes of various ages have been examined by analytical transmission electron microscopy (TEM) and electron microprobe analysis (EMPA). The stability of the various hydrate phases in the electron microscope is discussed. Although all are subject to damage in varying degrees, even the least stable phase, AFt, can be recognized in relict form in the TEM. The

I. G. Richardson; G. W. Groves

1993-01-01

202

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

203

Biaxial ratchetting with novel variations of kinematic hardening  

Microsoft Academic Search

Kinematic hardening and the associated concept of back-stress and its evolution are fundamental constitutive ingredients of classical plasticity theory used to simulate the inelastic material response under stress reversals. Cyclic plasticity addresses such response under a sequence of repeated stress reversals, which results in plastic strain accumulation, called ratchetting. Biaxial ratchetting occurs whenever the material is loaded in two directions

Yannis F. Dafalias; Heidi P. Feigenbaum

2011-01-01

204

Kinematic hardening rules in uncoupled modeling for multiaxial ratcheting simulation  

Microsoft Academic Search

An earlier paper by the authors evaluated the performance of several coupled models in simulating a series of uniaxial and biaxial ratcheting responses. This paper evaluates the performance of various kinematic hardening rules in an uncoupled model for the same set of ratcheting responses. A modified version of the Dafalias–Popov uncoupled model has been demonstrated to perform well for uniaxial

Shafiqul Bari; Tasnim Hassan

2001-01-01

205

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

206

Robust Combiners for Software Hardening Amir Herzberg and Haya Shulman  

E-print Network

techniques of reductions and code manipulation. Keywords: White-box security, software hardening, obfuscation-line software distribution and licensing, mo- bile agents, grid computing, and others. In white-box security the execution environment obtains full access to the program, and can observe and manipulate the execution, code

207

A Highly Flexible Hardened RTL Processor Core Based on LEON  

Microsoft Academic Search

We present a hardened RTL processor core based on LEON. Modifications are done at RT-Ievel to achieve high configurability in an early stage of the development process. The main parts of the processor core can be protected against single event upsets and single event transients. Results and tradeoffs are presented and discussed.

Michele Portolan; R. Leveugle

2005-01-01

208

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

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

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

209

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

210

Strain hardening of fibrin gels and plasma clots  

Microsoft Academic Search

Biological macromolecules have unique rheological properties that distinguish them from common synthetic polymers. Among these, fibrin has been studied extensively to understand the basic mechanisms of viscoelasticity as well as molecular mechanisms of coagulation disorders. One aspect of fibrin gel rheology that is not observed in most polymeric systems is strain hardening: an increase in shear modulus at strain amplitudes

Jagesh V. Shah; Paul A. Janmey

1997-01-01

211

Yielding and strain hardening of thin metal films on substrates  

Microsoft Academic Search

The author has shown that the very high strengths and high strain hardening rates exhibited by thin metal films on substrates can be understood by considering the effects of confinement on the motion of dislocations. Both the substrate and passivation and the obstacle dislocations already present in the film narrow the channels through which dislocations can move and this leads

William D. Nix

1998-01-01

212

Strain Hardening and Strength of Clay-Rich Fault Gouges  

Microsoft Academic Search

Frictional sliding experiments at confining pressures from 50 to 400 MPa were performed on thin layers of clay-rich fault gouges from locations along the San Andreas and Hayward faults in California as well as pure clays from other locations. Both dry and saturated, drained samples exhibited a strain hardening that increased systematically with increasing confining pressure for the each particular

C. A. Morrow; L. Q. Shi; J. D. Byerlee

1982-01-01

213

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

214

Strain Hardening of Polymer Glasses: Entanglements, Energetics, and Plasticity  

E-print Network

Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While stress-strain curves for a wide range of temperature can be fit to the functional form predicted by entropic network models, many other results are fundamentally inconsistent with the physical picture underlying these models. Stresses are too large to be entropic and have the wrong trend with temperature. The most dramatic hardening at large strains reflects increases in energy as chains are pulled taut between entanglements rather than a change in entropy. A weak entropic stress is only observed in shape recovery of deformed samples when heated above the glass transition. While short chains do not form an entangled network, they exhibit partial shape recovery, orientation, and strain hardening. Stresses for all chain lengths collapse when plotted against a microscopic measure of chain stretching rather than the macroscopic stretch. The thermal contribution to the stress is directly proportional to the rate of plasticity as measured by breaking and reforming of interchain bonds. These observations suggest that the correct microscopic theory of strain hardening should be based on glassy state physics rather than rubber elasticity.

Robert S. Hoy; Mark O. Robbins

2007-09-06

215

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

216

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

217

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

E-print Network

on a precipitation hardening process. The precipitation sequence in the Al-Mg-Si alloys is generally accepted [1 the precipitation process in Al-Mg-Si alloys has been extensively studied, the understand- ing of the hardeningPRECIPITATION HARDENING IN ALUMINUM ALLOY 6022 W.F. Miao and D.E. Laughlin Department of Materials

Laughlin, David E.

218

The effects of induction hardening on wear properties of AISI 4140 steel in dry sliding conditions  

Microsoft Academic Search

Wear behaviour of induction hardened AISI 4140 steel was evaluated under dry sliding conditions. Specimens were induction hardened at 1000 Hz for 6, 10, 14, 18, 27 s, respectively, in the inductor which was a three-turn coil with a coupling distance of 2.8 mm. Normalised and induction hardened specimens were fully characterised before and after the wear testing using hardness,

Y Totik; R Sadeler; H Altun; M Gavgali

2003-01-01

219

Cyclic loading of beams based on the Prager and Frederick–Armstrong kinematic hardening models  

Microsoft Academic Search

The kinematic hardening theory of plasticity based on the Prager and Frederick–Armstrong models are used to evaluate the cyclic loading behavior of a beam under the axial, bending, and thermal loads. The beam material is assumed to follow non-linear strain hardening property. The material's strain hardening curves in tension and compression are assumed to be both identical for the isotropic

H. Mahbadi; M. R. Eslami

2002-01-01

220

QUASISTATIC SMALL-STRAIN PLASTICITY IN THE LIMIT OF VANISHING HARDENING AND  

E-print Network

QUASISTATIC SMALL-STRAIN PLASTICITY IN THE LIMIT OF VANISHING HARDENING AND ITS NUMERICAL-independent evolution of the Prager-Ziegler-type model of linearized plasticity with hardening is shown to converge of energetic solutions we study the convergence of the solutions in the limit for hardening coefficients

Bartels, Soeren

221

IDENTIFICATION OF HARDENING PARAMETERS USING FINITE ELEMENT MODELS AND FULL-FIELD  

E-print Network

the heterogeneous strain fields on the identification of isotropic hardening parameters. Results are compared1 IDENTIFICATION OF HARDENING PARAMETERS USING FINITE ELEMENT MODELS AND FULL-FIELD MEASUREMENTS using full-field measurements. An orthotropic Hill criterion including an isotropic hardening

Paris-Sud XI, Université de

222

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

E-print Network

of penetration depth, the proposed method gives the range of strain for which the hardening law is precisely;Keywords: Steel alloy, spherical indentation, hardening law, average representative strain, confidence range of strain for which the hardening law is precisely identified. In some studies, no physical

223

From Dislocation Junctions to Forest Hardening R. Madec, B. Devincre, and L. P. Kubin  

E-print Network

and strain hardening in fcc crystals are examined with emphasis on the process of junction formation the stability of plastic flow, is called strain hardening. Its physical origin is understood in terms crystals and therefore to improve the physical content of current models for strain harden- ing

Devincre, Benoit

224

Cyclic strain hardening of nanocrystalline nickel B. Moser a,b,*, T. Hanlon a,c  

E-print Network

Cyclic strain hardening of nanocrystalline nickel B. Moser a,b,*, T. Hanlon a,c , K.S. Kumar d , S strain hardening and frequency-dependent fatigue life in electrodeposited nanocrystalline Ni subjected hardening 1. Introduction The cyclic deformation behavior of microcrystalline (mc) metals and alloys has

Suresh, Subra

225

Strong Strain Hardening in Nanocrystalline Nickel X. L. Wu,1,* Y. T. Zhu,2,  

E-print Network

Strong Strain Hardening in Nanocrystalline Nickel X. L. Wu,1,* Y. T. Zhu,2, Y. G. Wei,1 and Q. Wei3 strain hardening has hitherto been considered an intrinsic behavior for most nanocrystalline (NC) metals hardening in NC nickel with a grain size of $20 nm under large plastic strains. Contrary to common belief

Zhu, Yuntian T.

226

A cell theory for stage IV work hardening of metals and semiconductors  

E-print Network

to be close to the melting temperature and the strain rate not too high in order for the work hardening rate and not lead to new hardening ; the misorientation between cells or subgrains increases with strain misorientation and hardening and considers the former to be a by-product of large strains ; specimen shape

Paris-Sud XI, Université de

227

Correlation of tensile and flexural responses of strain softening and strain hardening cement composites  

E-print Network

Correlation of tensile and flexural responses of strain softening and strain hardening cement reinforced concrete: strain softening and strain hardening materials. The simulation revealed that the direct softening material while a good prediction for strain hardening material was obtained. The importance

Mobasher, Barzin

228

Cold Sores (Orofacial Herpes)  

MedlinePLUS

... on the lips and chin are typical of herpes simplex infection. Overview Herpes simplex infection of the mouth and face, known as orofacial herpes simplex, herpes labialis, cold sores, or fever blisters, is ...

229

Cyanobacteria in Cold Ecosystems  

Microsoft Academic Search

Perennially cold environments in which temperatures remain below 5°C are common throughout the biosphere (Margesin and Häggblom\\u000a 2007). In these habitats, the persistent cold temperatures are often accompanied by freeze—thaw cycles, extreme fluctuations\\u000a in irradiance (including ultraviolet radiation), and large variations in nutrient supply and salinity. As a result of these\\u000a constraints, polar and alpine environments contain a reduced biodiversity,

Frédéric Zakhia; Anne-Dorothee Jungblut; Arnaud Taton; Warwick F. Vincent; Annick Wilmotte

230

Cold dark matter heats up  

E-print Network

One of the principal discoveries in modern cosmology is that standard model particles (including baryons, leptons and photons) together comprise only 5% of the mass-energy budget of the Universe. The remaining 95% consists of dark energy and dark matter (DM). Consequently our picture of the universe is known as {\\Lambda}CDM, with {\\Lambda} denoting dark energy and CDM cold dark matter. {\\Lambda}CDM is being challenged by its apparent inability to explain the low density of DM measured at the centre of cosmological systems, ranging from faint dwarf galaxies to massive clusters containing tens of galaxies the size of the Milky Way. But before making conclusions one should carefully include the effect of gas and stars, which were historically seen as merely a passive component during the assembly of galaxies. We now understand that these can in fact significantly alter the DM component, through a coupling based on rapid gravitational potential fluctuations.

Pontzen, Andrew

2014-01-01

231

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

NASA Astrophysics Data System (ADS)

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

Song, Youshuo; Yu, Zhonghua

2013-11-01

232

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

233

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

234

Cold Fusion, A Journalistic Investigation  

Microsoft Academic Search

Author of the recent book, The Rebirth of Cold Fusion, and founder of New Energy Times, Steven B. Krivit presents a summary of cold fusion's, past, present and possible future. This talk will briefly review five highlights of the recent New Energy Times investigation into cold fusion research:1. Analysis of early studies that supposedly disproved cold fusion.2. Key early corroborations

Steven B. Krivit

2005-01-01

235

Hardening electronic devices against very high total dose radiation environments  

NASA Technical Reports Server (NTRS)

The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

Buchanan, B.; Shedd, W.; Roosild, S.; Dolan, R.

1972-01-01

236

Oxygen diffusion hardening of cp-titanium for biomedical applications.  

PubMed

Common methods to increase the wear resistance of titanium by surface hardening in biomedical applications, such as chemical/physical vapour deposition techniques or thermal/electrochemical oxidation, result in a layer of titanium dioxide or titanium nitride on the metal surface with a sharp interface between the hard and brittle coating and the ductile metallic substrate. A major disadvantage of these methods is that the sharp transition in material properties may cause exfoliation of these coatings. In this work, a two-step heat treatment was used to investigate oxygen diffusion hardening and its capability to produce hard surfaces with a transition zone between the coating and the ductile substrate. During the first step, the native oxide layer was strengthened. In the second step, oxygen diffusion was activated and a transition zone was formed. Different methods of analysis confirmed the success of the thermal treatment, as well as the change of the mechanical properties. PMID:20876962

Hertl, C; Werner, E; Thull, R; Gbureck, U

2010-10-01

237

ORIGIN OF THE COSMIC-RAY SPECTRAL HARDENING  

SciTech Connect

Recent data from ATIC, CREAM, and PAMELA indicate that the cosmic-ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV nucleon{sup -1}. We propose that the hardening is an interstellar propagation effect that originates from a spatial change of the cosmic-ray transport properties in different regions of the Galaxy. The key hypothesis is that the diffusion coefficient is not separable into energy and space variables as usually assumed. Under this scenario, we can reproduce the observational data well. Our model has several implications for cosmic-ray acceleration/propagation physics and can be tested by ongoing experiments such as the Alpha Magnetic Spectrometer or Fermi-LAT.

Tomassetti, Nicola, E-mail: nicola.tomassetti@pg.infn.it [INFN-Sezione di Perugia, 06122 Perugia (Italy)

2012-06-10

238

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

239

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

240

Proteomics Analysis Reveals Post-Translational Mechanisms for Cold-Induced Metabolic Changes in Arabidopsis  

PubMed Central

Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance to freezing—a phenomenon known as cold acclimation. Cold also induces rapid metabolic changes, which provide instant protection before temperature drops below freezing point. The molecular mechanisms for such rapid metabolic responses to cold remain largely unknown. Here, we use two-dimensional difference gel electrophoresis (2-D DIGE) analysis of sub-cellular fractions of Arabidopsis thaliana proteome coupled with spot identification by tandem mass spectrometry to identify early cold-responsive proteins in Arabidopsis. These proteins include four enzymes involved in starch degradation, three HSP100 proteins, several proteins in the tricarboxylic acid cycle, and sucrose metabolism. Upon cold treatment, the Disproportionating Enzyme 2 (DPE2), a cytosolic transglucosidase metabolizing maltose to glucose, increased rapidly in the centrifugation pellet fraction and decreased in the soluble fraction. Consistent with cold-induced inactivation of DPE2 enzymatic activity, the dpe2 mutant showed increased freezing tolerance without affecting the C-repeat binding transcription factor (CBF) transcriptional pathway. These results support a model that cold-induced inactivation of DPE2 leads to rapid accumulation of maltose, which is a cold-induced compatible solute that protects cells from freezing damage. This study provides evidence for a key role of rapid post-translational regulation of carbohydrate metabolic enzymes in plant protection against sudden temperature drop. PMID:21242321

Xu, Shou-Ling; Oses-Prieto, Juan A.; Putil, Sunita; Xu, Peng; Li, Kathy H.; Maltby, David A.; An, Liz-He; Burlingame, Alma L.; Deng, Zhi-Ping; Wang, Zhi-Yong

2011-01-01

241

Fatigue limit and durability of precipitation-hardening austenitic steels  

Microsoft Academic Search

1.Alloying with chromium raises the fatigue limit of austenitic steel in the quenched condition. In the hardened condition the presence of ~15% Cr in austenitic steel lowers the fatigue limit due to precipitation of Cr23C6 carbides in the grain boundaries. For long-term operation under ordinary cyclic loading conditions, high-strength austenitic steel with an elevated chromium content is unsuitable. The steel

Yu. K. Kovneristyi; S. E. Gurevich; V. M. Blinov; O. A. Bannykh; V. A. Rudman

1971-01-01

242

Surface zone hardening during the bending fatigue of nickel  

Microsoft Academic Search

Fatigue tests were performed on commercially pure nickel at room temperature, utilizing fully reversed bending, in the environments\\u000a of dry air and 2 vol pct nitric acid in water. It was found that the surface hardening from fatigue was the same for both\\u000a environments, at any given bending moment. A limiting surface Vickers hardness of ? 160 kgmm-2 occurred in

C. E. Price; J. A. Fila

1981-01-01

243

Elastic constant versus temperature behavior of three hardened maraging steels  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

244

An advanced, radiation hardened bulk CMOS/LSI technology  

NASA Technical Reports Server (NTRS)

An advanced, second generation, bulk, Si-gate CMOS process is described. This process is capable of producing LSI and VLSI parts that are latch-up free and hardened to total dose levels in excess of 2 x 10 to the 5th rad-Si for applications in space and weapons radiation environments. Two memories designed to use this process are also described. Both circuits are 4096-bit, static CMOS RAMs.

Schroeder, J. E.; Lichtel, R. L.; Gingerich, B. L.

1981-01-01

245

High-strength age hardening copper–titanium alloys: redivivus  

Microsoft Academic Search

In this review the decomposition of supersaturated Cu–Ti solid solutions and subsequent microstructural evolution are discussed in terms of modern views of precipitation from solid solution. This update is motivated by an anticipated emergence of these alloys as technologically significant high-strength, high-conductivity, precipitation hardened alloys over the next decade replacing conventional Cu–Be alloys in numerous applications. The decomposition of Cu–Ti

W. A. Soffa; D. E. Laughlin

2004-01-01

246

Mechanism of the hardening effect of solvents on polymers  

Microsoft Academic Search

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

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

1975-01-01

247

Reduction of metal artifacts: beam hardening and photon starvation effects  

NASA Astrophysics Data System (ADS)

The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. The cause and occurrence of metal-artifacts are primarily due to beam hardening, scatter, partial volume and photon starvation; however, the contribution to the artifacts from each of them depends on the type of hardware. A comparison of CT images obtained with different metallic hardware in various applications, along with acquisition and reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a metal beam hardening correction (BHC) and a projection-completion based metal artifact reduction (MAR) algorithms were developed, and applied on phantom and clinical CT scans with various metallic implants. Stainless-steel and Titanium were used to model and correct for metal beam hardening effect. In the MAR algorithm, the corrupted projection samples are replaced by the combination of original projections and in-painted data obtained by forward projecting a prior image. The data included spine fixation screws, hip-implants, dental-filling, and body extremity fixations, covering range of clinically used metal implants. Comparison of BHC and MAR on different metallic implants was used to characterize dominant source of the artifacts, and conceivable methods to overcome those. Results of the study indicate that beam hardening could be a dominant source of artifact in many spine and extremity fixations, whereas dental and hip implants could be dominant source of photon starvation. The BHC algorithm could significantly improve image quality in CT scans with metallic screws, whereas MAR algorithm could alleviate artifacts in hip-implants and dentalfillings.

Yadava, Girijesh K.; Pal, Debashish; Hsieh, Jiang

2014-03-01

248

On the origin of strain hardening in glassy polymers  

Microsoft Academic Search

The influence of network density on the strain hardening behaviour of amorphous polymers is studied. The network density of polystyrene is altered by blending with poly(2,6-dimethyl-1,4-phenylene-oxide) and by cross-linking during polymerisation. The network density is derived from the rubber-plateau modulus determined by dynamic mechanical thermal analysis. Subsequently uniaxial compression tests are performed to obtain the intrinsic deformation behaviour and, in

H. G. H. van Melick; L. E. Govaert; H. E. H. Meijer

2003-01-01

249

Theory of plastic flow in strain-hardened metals  

Microsoft Academic Search

A major unsolved problem in the theory of plastic flow of strain-hardened metals is the falling reversible flow-stress ratio at high temperature. In this paper it is argued that both the irreversible and reversible changes in stress at high temperature are a consequence of dislocation climb. The reversible difference is a consequence of climb-controlled rearrangement while the irreversible difference is

Thomas H. Alden

1972-01-01

250

On the strain-hardening parameters of metals  

Microsoft Academic Search

The applicability of the Ludwik, Hollomon, Swift and Voce equations in describing the stress - strain curves of metals was\\u000a investigated. Calculated uniform strain values were found to depend on the equation used. Even when the Hollomon equation\\u000a gave a high linear correlation coefficient in log-log coordinates, the strain-hardening exponent n could give an erroneous\\u000a uniform strain. The equation with

H. J. Kleemola; M. A. Nieminen

1974-01-01

251

Endolithic microbial life in hot and cold deserts  

NASA Technical Reports Server (NTRS)

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

Friedmann, E. I.

1980-01-01

252

Strain hardening behavior of ARMCO iron processed by ECAP  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

253

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

254

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

E-print Network

is through precipitation reactions. Precipitation hardening is the process of hardening or strengthening in the precipitation hardening process is aging. It is the process of precipitating incoherent precipitates fromPrecipitation hardening Objective The objective of this laboratory is for you to explore

Braun, Paul

255

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

256

Age hardening characteristics and mechanical behavior of Al-Cu-Li-Zr-In alloys  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the age-hardening response and cryogenic mechanical properties of superplastic Al-Cu-Li-Zr-In alloys. Two alloys with compositions Al-2.65Cu-2.17Li-O.13Zr (baseline) and Al-2.60Cu-2.34Li-0.16Zr-0.17In were scaled-up from 30 lb permanent mold ingots to 350 lb DC (direct chill) ingots and thermomechanically processed to 3.2 mm thick sheet. The microstructure of material which contained the indium addition was partially recrystallized compared to the baseline suggesting that indium may influence recrystallization behavior. The indium-modified alloy exhibited superior hardness and strength compared to the baseline alloy when solution-heat-treated at 555 C and aged at 160 C or 190 C. For each alloy, strength increased and toughness was unchanged or decreased when tested at - 185 C compared to ambient temperature. By using optimized heat treatments, the indium-modified alloy exhibited strength levels approaching those of the baseline alloy without deformation prior to aging. The increase in strength of these alloys in the T6 condition make them particularly attractive for superplastic forming applications where post-SPF parts cannot be cold deformed to increase strength.

Wagner, John A.

1989-01-01

257

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

258

How cold pool triggers deep convection?  

NASA Astrophysics Data System (ADS)

The cold pool in the boundary layer is often considered a major triggering mechanism of convection. Here, presented are basic theoretical considerations on this issue. Observations suggest that cold pool-generated convective cells is available for shallow maritime convection (Warner et al. 1979; Zuidema et al. 2012), maritime deep convection (Barnes and Garstang 1982; Addis et al. 1984; Young et al. 1995) and continental deep convection (e.g., Lima and Wilson 2008; Flamant 2009; Lothon et al. 2011; Dione et al. 2013). Moreover, numerical studies appear to suggest that cold pools promote the organization of clouds into larger structures and thereby aid the transition from shallow to deep convection (Khairoutdinov and Randall 2006, Boing et al. 2012, Schlemmer and Hohenegger, 2014). Even a cold--pool parameterization coupled with convection is already proposed (Grandpeix and Lafore 2010: but see also Yano 2012). However, the suggested link between the cold pool and deep convection so far is phenomenological at the best. A specific process that the cold pool leads to a trigger of deep convection must still to be pinned down. Naively, one may imagine that a cold pool lifts up the air at the front as it propagates. Such an uplifting leads to a trigger of convection. However, one must realize that a shift of air along with its propagation does not necessarily lead to an uplifting, and even if it may happen, it would not far exceed a depth of the cold pool itself. Thus, the uplifting can never be anything vigorous. Its thermodynamic characteristics do help much either for inducing convection. The cold-pool air is rather under rapid recovering process before it can induce convection under a simple parcel-lifting argument. The most likely reason that the cold pool may induce convection is its gust winds that may encounter an air mass from an opposite direction. This induces a strong convergence, also leading to a strong uplifting. This is an argument essentially developed by Moncrieff and Liu (1999). As a whole, in attempting a statistical description of boundary-layer processes, the cold pool is essentially nothing other than an additional contribution to a TKE (turbulent kinetic energy) budget. Significance of trigger of convection by cold pool in context of convection parameterization must also be seen with much caution. Against a common misunderstanding, current convection parameterization is not designed to describe a trigger process of individual convection. In this respect, process studies on cold pool do not contribute to improvements of convection parameterization until a well-defined parameterization formulation for individual convection processes is developed. Even before then a question should also be posed whether such a development is necessary. Under a current mass-flux convection parameterization, a more important process to consider is re-evaporative cooling of detrained cloudy air, which may also be associated with downdraft, possibly further leading to a generation of a cold pool. Yano and Plant (2012) suggest, from a point of view of the convective-energy cycle, what follows would be far less important than the fact the re-evaporation induces a generation of convective kinetic energy (though it may initially be considered TKE). Both well-focused convective process studies as well as convection parameterization formulation would be much needed.

Yano, Jun-Ichi

2014-05-01

259

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

260

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.

261

Rapid Prototyping  

NASA Technical Reports Server (NTRS)

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

1999-01-01

262

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

263

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

264

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

PubMed Central

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

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

2012-01-01

265

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

266

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 PMID:16653054

Mizuno, Koichi

1992-01-01

267

Cold War Propaganda.  

ERIC Educational Resources Information Center

Briefly discusses the development of Cold War propaganda in the United States, Canada, and the USSR after 1947. Presents two movie reviews and a Canadian magazine advertisement of the period which illustrate the harshness of propaganda used by both sides in the immediate postwar years. (GEA)

Bennett, Paul W.

1988-01-01

268

Cold Spring Mount Washington  

E-print Network

Spring Mount Washington Light Rail McAuley Hall Falls@ Woodheights Falls@ 43rd Keswick North Bldg Keswick 83 JonesFallsExpy 83 JonesFallsExpy 83 FallsRd N S EW Homewood - Mt. Washington Shuttle NextBus textth Keswick North Building Falls at 42nd Falls at Cold Spring Mount Washington Light Rail McAuley Hall

Hattar, Samer

269

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

270

Baby, it's cold outside....  

PubMed

For officers and other employees stationed outdoors in parking areas or on perimeter patrol during cold weather the risks of hypothermia and frostbite may be very real. In this article, the author explains how these two serious medical conditions can be prevented and treated. PMID:22423532

Kissane, Rhonda

2012-01-01

271

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

272

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

NASA Technical Reports Server (NTRS)

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

Allen Phillip A.; Wilson, Christopher D.

2003-01-01

273

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

274

A two-surface model describing ratchetting behaviors and transient hardening under nonproportional loading  

Microsoft Academic Search

A new superposed rule of Mroz's kinematic hardening rule and Ziegler's kinematic hardening rule based on two-surface model\\u000a is proposed in the paper. Some experimental results on ratchetting of 2014-T6 aluminum alloy are predicted very well under\\u000a multiaxial loading. In addition the conformability of the model is discussed for transient cyclic hardening under two kinds\\u000a of nonproportional cyclic loading paths,

Chen Xu; A. Abel

1996-01-01

275

A two-surface model describing ratchetting behaviors and transient hardening under nonproportional loading  

NASA Astrophysics Data System (ADS)

A new superposed rule of Mroz's kinematic hardening rule and Ziegler's kinematic hardening rule based on two-surface model is proposed in the paper. Some experimental results on ratchetting of 2014-T6 aluminum alloy are predicted very well under multiaxial loading. In addition the conformability of the model is discussed for transient cyclic hardening under two kinds of nonproportional cyclic loading paths, i.e. square and rhombic path.

Xu, Chen; Abel, A.

1996-11-01

276

XRD investigation of microstructure strengthening mechanism of shot peening on laser hardened 17-4PH  

Microsoft Academic Search

The influence of shot peening on microstructure of laser hardened 17-4PH was investigated by using X-ray diffraction profiles. The domain size, microstrain and dislocation in different depths were calculated via Voigt method and dislocation density calculation method according to Williamson's work. Two typical materials in laser hardened 17-4PH (matrix material and laser hardened material) and three families of crystalline planes

Zhou Wang; Weizhi Luan; Junjie Huang; Chuanhai Jiang

2011-01-01

277

Nonlinear Static -1D Plasticity -Various Forms of Isotropic Hardening by Louie L. Yaw  

E-print Network

, consistency param- eter, internal hardening variable, equivalent plastic strain, flow rule, consistency No Hardening - Perfect Plasticity Plastic Strain, p Stress, G( p )= y (a) 0 1 2 3 4 5 x 10 -3 0 5 10 15 20 25 30 35 40 45 50 Linear Hardening Plastic Strain, p Stress, G( p )= y +K p (b) 0 1 2 3 4 5 x 10 -3 0 5

Yaw, Louis L.

278

Electromagnetic Characterization of the Depth of Surface-Hardening in Steel  

Microsoft Academic Search

The four-point alternating current potential drop (ACPD) method has the potential to evaluate different depths of case hardening in steel. The potential drop was measured on a series of induction-hardened and carburized steel rod samples. It was shown that four-point ACPD is a promising technique for distinguishing between different depths of case hardening. Especially in the low-frequency range of the

C. Zhang; N. Bowler

2009-01-01

279

Cold Weather and Cardiovascular Disease  

MedlinePLUS

Cold Weather and Cardiovascular Disease Updated:Oct 28,2014 Th is winter season will bring cooler temperatures and ice ... for some. It’s important to know how cold weather can affect your heart, especially if you have ...

280

Hardening communication ports for survival in electrical overstress environments  

NASA Technical Reports Server (NTRS)

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

Clark, O. Melville

1991-01-01

281

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

282

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. PMID:21234087

Miller, Penny F.

1991-01-01

283

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

E-print Network

Rapid Gel Formation and Adhesion in Photocurable and Biodegradable Block Copolymers with High DOPA, 2005 ABSTRACT: Marine mussels anchor to a variety of surfaces in turbulent intertidal zones through the use of adhesive plaques formed from hardened mussel adhesive proteins (MAPs). It is believed that 3

284

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

SciTech Connect

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

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

2013-12-16

285

Radial cold trap  

DOEpatents

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

Grundy, B.R.

1981-09-29

286

Cold heteromolecular dipolar collisions.  

PubMed

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

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

2011-11-14

287

Hot and Cold  

NSDL National Science Digital Library

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

Sciencenter

2014-08-27

288

Genomewide Transcriptional Analysis of the Cold Shock Response in Bacillus subtilis  

Microsoft Academic Search

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

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

2002-01-01

289

Cold nuclear fusion  

Microsoft Academic Search

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

Johann Rafelski; Steven E. Jones

1987-01-01

290

Clumpy cold dark matter  

NASA Technical Reports Server (NTRS)

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

Silk, Joseph; Stebbins, Albert

1993-01-01

291

Teachers Debate Cold Fusion  

NASA Astrophysics Data System (ADS)

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

Kowalski, Ludwik

2005-12-01

292

COLPEX - Cold Pool Experiment  

Microsoft Academic Search

Planning has started towards designing a new field campaign aimed at studying the behaviour of the boundary layer over complex terrain. Of specific interest is the formation of cold-pools in valleys during stable night-time conditions. The field campaign will run continuously until the end of the winter in 2009\\/10. The experiment will make use of a wide variety of ground-based

H. Wells; J. Price; V. Horlacher; P. F. Sheridan; S. B. Vosper; A. R. Brown; S. D. Mobbs; A. N. Ross

2009-01-01

293

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

294

Cold fusion prospects  

Microsoft Academic Search

The requirements for cold fusion may include, but are not limited to the following: a nuclear mass-energy resonance with an excitation level in the compound nucleus or in two output nuclei; very high density; a large neutron capture cross-section isotope and a neutron-rich isotope; overlapping de Broglie interaction wavelengths; nuclear spin and polarizability compatibility; and\\/or catalytic action by a passing

1989-01-01

295

Discrepant hardening observed in cosmic-ray elemental spectra  

E-print Network

The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here we report results from the first two flights of ~70 days, which indicate hardening of the elemental spectra above ~200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ~1015 eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible ...

Ahn, H S; Bagliesi, M G; Beatty, J J; Bigongiari, G; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Lutz, L; Maestro, P; Malinin, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, J; Nam, S; Nutter, S L; Park, I H; Park, N H; Seo, E S; Sina, R; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y; 10.1088/2041-8205/714/1/L89

2010-01-01

296

Discrepant Hardening Observed in Cosmic-ray Elemental Spectra  

NASA Astrophysics Data System (ADS)

The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of ~70 days, which indicate hardening of the elemental spectra above ~200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ~1015 eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

Ahn, H. S.; Allison, P.; Bagliesi, M. G.; Beatty, J. J.; Bigongiari, G.; Childers, J. T.; Conklin, N. B.; Coutu, S.; DuVernois, M. A.; Ganel, O.; Han, J. H.; Jeon, J. A.; Kim, K. C.; Lee, M. H.; Lutz, L.; Maestro, P.; Malinin, A.; Marrocchesi, P. S.; Minnick, S.; Mognet, S. I.; Nam, J.; Nam, S.; Nutter, S. L.; Park, I. H.; Park, N. H.; Seo, E. S.; Sina, R.; Wu, J.; Yang, J.; Yoon, Y. S.; Zei, R.; Zinn, S. Y.

2010-05-01

297

DISCREPANT HARDENING OBSERVED IN COSMIC-RAY ELEMENTAL SPECTRA  

SciTech Connect

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

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

2010-05-01

298

A radiation-hardened, computer for satellite applications  

SciTech Connect

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

Gaona, J.I. Jr.

1996-08-01

299

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

E-print Network

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

Stockie, John

300

The study of influenced factors affecting to quality of cylindrical grinding harden AISI 4140 steel  

Microsoft Academic Search

The objective of this research was to study factors, which were affected on surface roughness and roundness in cylindrical grinding of harden AISI 4140 steel. Specimen used in the experiment was AISI 4140 steel that hardening at 51±3 HRC. Studied factors were consisted of revolution speed of workpiece, feed rate, and depth of cut. Full factorial experimental design was conducted

Komson Jirapatarasilp; Sittichai Kaewkuekool; P. Klahan

2010-01-01

301

A Novel Sort Error Hardened 10T SRAM Cells for Low Voltage Operation  

E-print Network

A Novel Sort Error Hardened 10T SRAM Cells for Low Voltage Operation In-Seok Jung Department hardened 10T SRAM cells with high static noise margin (SNM) are proposed for low voltage operation. The proposed NMOS stacked SRAM cell operates normally with higher read SNM near to sub- threshold region

Ayers, Joseph

302

Low-Cost Hardening of Image Processing Applications Against Soft Errors Ilia Polian1,2  

E-print Network

of their occurrence (ac- cording to the roadmaps, the estimated frequency of soft er- rors, called soft error rate costs for handling soft errors by us- ing radiation-hardened (radhard) manufacturing technologyLow-Cost Hardening of Image Processing Applications Against Soft Errors Ilia Polian1,2 Bernd Becker

Polian, Ilia

303

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

304

An upper bound algorithm for limit and shakedown analysis of bounded linearly kinematic hardening structures  

Microsoft Academic Search

The paper develops a new FEM based algorithm for shakedown analysis of structures made of elastic plastic bounded linearly kinematic hardening material. The hardening effect is simulated by using a two-surface plastic model to bound the Melan-Prager model. The initial yield surface can translate inside the bounding surface, without changing its shape and size. The translated yield surface may touch

Phu Tinh Phm; Manfred Staat

2013-01-01

305

A robust kinematic hardening rule for cyclic plasticity with ratchetting effects  

Microsoft Academic Search

Summary A robust kinematic hardening rule is proposed which appropriately blends the deviatoric stress rate rule and the Tseng-Lee rule in order to satisfy both the experimental observations made by Phillips et al. [1]–[5] and the nesting of the yield surface to the limit surface. The work presented in Part I is confined to the theoretical formulation of kinematic hardening

G. Z. Voyiadjis; S. M. Sivakumar

1991-01-01

306

On the performance of kinematic hardening rules in predicting a class of biaxial ratcheting histories  

Microsoft Academic Search

It is well known that strain-symmetric axial cycling of thin-walled metal tubes in the presence of pressure results in a progressive accumulation (ratcheting) of circumferential strain. It was previously demonstrated that the prediction of the rate of ratcheting under constant internal pressure, by nonlinear kinematic hardening models, is very sensitive to the hardening rule adopted. It was shown that the

E. Corona; T. Hassan; S. Kyriakides

1996-01-01

307

Plastic deformation under cyclic loading using two-back stress hardening models  

Microsoft Academic Search

In the present work, the constitutive relations based on the combination of two-back stresses are developed using the Armstrong–Frederick and Phillips type hardening rules in order to describe the plastic strain accumulation under a cyclic loading. Using the combined kinematic hardening rules, the ratcheting behavior under uniaxial cyclic loading is investigated and compared with numerical results. Various evolutions of the

Su-Jin Yun; Anthony Palazotto

2008-01-01

308

Radiation response of two Harris semiconductor radiation hardened 1k CMOS RAMs  

SciTech Connect

This paper describes the testing of two types 1K CMOS static RAMs in various transient and steady state ionizing radiation environments. Type HM 6551R (256x4 bits) and type HM 6508R (1024x1 bit) RAMs were evaluated. The RAMs are radiation hardened versions of Harris' commercial RAMs. A brief description of the radiation hardened process is presented.

Abare, W.E.; Huffman, D.D.; Moffett, G.E.

1982-12-01

309

The surface fatigue life of contour induction hardened AISI 1552 gears  

Microsoft Academic Search

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened,

Dennis P. Townsend; Alan Turza; Mike Chaplin

1995-01-01

310

Effects of strain hardening and stress state on fatigue crack closure  

Microsoft Academic Search

A theoretical analysis is performed for the effect of strain hardening on fatigue crack closure in plane stress and plane strain conditions based on a modified strip yield model. It is shown that the effect of the strain hardening exponent n on the opening stress ratio is small, less than 1.3% in plane stress and about 10% in plane strain,

T. Chang; W. Guo

1999-01-01

311

Selective case hardening of plain steel by carbon alloying with a plasma transferred arc (PTA) technique  

Microsoft Academic Search

The present work was undertaken in order to study the possibility of case hardening of a plain steel using the Plasma Transferred Arc (PTA) alloying process. It was found that, depending on the PTA operation parameters and cooling rates, either carburizing or case hardening can be obtained. The depth of carburizing reaches a depth up to 1 mm and can

J. Nikolaou; L. Bourithis; G. Papadimitriou

2003-01-01

312

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

313

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

NASA Astrophysics Data System (ADS)

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

2007-04-01

314

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

NASA Astrophysics Data System (ADS)

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.; Yoon, J. W.; Dick, R. E.

2011-05-01

315

Some like it cold: response of microorganisms to cold shock  

Microsoft Academic Search

Bacteria respond to an abrupt decrease in temperature with a specific response, in which cold-induced proteins (CIPs) are\\u000a transiently expressed at a higher level. Employing two-dimensional gel electrophoresis, several CIPs have been identified.\\u000a In spite of this, the overall function of the cold shock response is unclear. Recently, the main attention has focused on\\u000a a group of conserved cold shock

Peter Graumann; Mohamed A. Marahiel

1996-01-01

316

Alloy hardening and softening in binary molybdenum alloys as related to electron concentration.  

NASA Technical Reports Server (NTRS)

Determination of the effects of alloy additions of Hf, Ta, W, Re, Os, Ir, and Pt on the hardness of Mo. Special emphasis was placed on alloy softening in these binary Mo alloys. A modified microhardness test unit permitted hardness determinations at homologous temperatures ranging from 0.02 to 0.15, where alloy softening normally occurs in bcc alloys. Results showed that alloy softening was produced by those elements having an excess of s + d electrons compared to Mo while those elements having an equal number or fewer s + d electrons than Mo failed to produce alloy softening. The magnitude of the softening and the amount of solute element at the hardness minimum diminished rapidly with increasing test temperature. At solute concentrations where alloy softening was observed, the temperature sensitivity of hardness was lowered. For solute elements having an excess of s + d electrons or fewer s + d electrons than Mo, alloy softening and alloy hardening can be correlated with the difference in number of s + d electrons of the solute element and Mo.

Stephens, J. R.; Witzke, W. R.

1972-01-01

317

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

SciTech Connect

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

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

2012-02-15

318

Annihilating cold dark matter  

PubMed

Structure formation with cold dark matter (CDM) predicts halos with a central density cusp, which are observationally disfavored. If CDM particles have an annihilation cross section sigmav approximately 10(-29)(m/GeV) cm(2), then annihilations will soften the cusps. We discuss plausible scenarios for avoiding the early Universe annihilation catastrophe that could result from such a large cross section. The predicted scaling of core density with halo mass depends upon the velocity dependence of sigmav, and s-wave annihilation leads to a core density nearly independent of halo mass, which seems consistent with observations. PMID:11030890

Kaplinghat; Knox; Turner

2000-10-16

319

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

320

Peregrinations on cold fusion  

SciTech Connect

Attention is focused on the possibility of resonance-enhanced deuteron Coulomb barrier penetration. Because of the many-body nature of the interactions of room-temperature deuterons diffusing through a lattice possessing deuterons in many of the interstitial positions, the diffusing deuterons can resonate on the atomic scale in the potential wells bounded by the ascending walls of adjacent Coulomb barriers and thereby penetrate the Coulomb barriers in a fashion vastly underestimated by two-body calculations in which wells for possible resonance are absent. Indeed, perhaps the lack of robust reproducibility in cold fusion originates from the narrowness of such transmission resonances. 4 refs., 1 fig.

Turner, L.

1989-01-01

321

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

322

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

323

The limits to hardening electronic boxes to IEMP coupling  

NASA Astrophysics Data System (ADS)

Experimental investigations of the IEMP coupling processes within electronics enclosures have determined that there are practical limits to the effectiveness of IEMP hardening approaches. The use of low-electron-emission coatings or potting compounds and ground planes reduces the IEMP coupling to those processes which occur within the circuit boards themselves. Depending on the thickness of the circuit board, the IEMP coupling may be dominated by the bulk photocurrents emitted within the dielectric or the dipole layer formed over the metallic conductors. Results of this study indicate that IEMP also has a low-impedance coupling mechanism governed by secondary electrons which may be collected by circuit potentials as low as +5 volts.

Seidler, W.; Keyser, R.; Walters, D.; Harper, H.

1982-12-01

324

Relationship between microstructure and degree of hardening of air-dried maji-soils under different pH conditions  

Microsoft Academic Search

Some of the physical properties of the Maji-soils in Okinawa Island, Japan, cause problems, namely severe hardening by air-drying. Although the degree of hardening by air-drying is especially high under high-pH conditions, the mechanism of hardening enhancement associated with the pH has not been elucidated yet. In order to investigate the mechanism underlying hardening enhancement, observation of soil micromorphological characteristics

Hideo Kubotera

2004-01-01

325

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

PubMed

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

Mac Irving, R; Lanphear, F O

1967-10-01

326

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

327

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

328

Methodology for the evaluation of yield strength and hardening behavior of metallic materials by indentation with spherical tip  

Microsoft Academic Search

This article presents a methodology for evaluating the yield strength and hardening behavior of metallic materials by spherical indentation. Two types of assumed material behaviors with a pure elastic-Hollomon's power law hardening and a pure elastic-linear hardening were considered separately in the models of spherical indentation. The numerical relationships between the material properties and indentation responses were established on the

Dejun Ma; Chung Wo Ong; Jian Lu; Jiawen He

2003-01-01

329

Revised for J. Non-Newtonian Fluid Mech. February 25, 1999 DYNAMICS OF WEAKLY STRAIN-HARDENING FLUIDS  

E-print Network

Revised for J. Non-Newtonian Fluid Mech. February 25, 1999 DYNAMICS OF WEAKLY STRAIN-HARDENING the transient viscoelastic response of weakly strain-hardening fluids to imposed elongational deformation some important aspects of the fluid kinematics exhibited by weakly strain-hardening fluids during

330

Influence of severe plastic deformation on the precipitation hardening of a FeSiTi steel , X. Sauvage1  

E-print Network

. Such a scenario would give rise to an increase of the strain hardening and subsequently to an increased ductility1 Influence of severe plastic deformation on the precipitation hardening of a FeSiTi steel A of the microstructure affects the precipitation kinetics and the spatial distribution of the secondary hardening

Boyer, Edmond

331

lack of strain hardening is believed to contrib-ute to the low tensile ductility of nanocrystalline  

E-print Network

lack of strain hardening is believed to contrib- ute to the low tensile ductility to the Hall-Petch effect, it would be seen in Fig. 1A as work hardening, because the number of stacking faults-Petch effect as stemming from increased work hardening in small grains (30, 31) can certainly be excluded

Schmidt, Steven K.

332

Is It A Cold Or The Flu? Symptoms Cold Flu  

E-print Network

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

O'Toole, Alice J.

333

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

NASA Technical Reports Server (NTRS)

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

Musacchia, X. J.

1972-01-01

334

Rapid prototyping of rapid prototyping machines  

E-print Network

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

Moyer, Ilan Ellison

2008-01-01

335

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

2013-09-01

336

Cold Dark Matter Resuscitated?  

E-print Network

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

Martin White; Douglas Scott; Joe Silk; Marc Davis

1995-08-02

337

Hot Planet - Cold Comfort  

NSDL National Science Digital Library

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

338

Cold isopressing method  

DOEpatents

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

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

2003-01-01

339

Experiments in cold fusion  

SciTech Connect

The work of Steve Jones and others in muon-catalyzed cold fusion of deuterium and hydrogen suggests the possibility of such fusion catalyzed by ions, or combinations of atoms, or more-or-less free electrons in solid and liquid materials. A hint that this might occur naturally comes from the heat generated in volcanic action in subduction zones on the earth. It is questionable whether the potential energy of material raised to the height of a midocean ridge and falling to the depth of an ocean trench can produce the geothermal effects seen in the volcanoes of subduction zones. If the ridge, the trench, the plates, and the asthenosphere are merely visible effects of deeper density-gradient driven circulations, it is still uncertain that observed energy-concentration effects fit the models.

Palmer, E.P.

1986-03-28

340

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

341

Non Radiation Hardened Microprocessors in Spaced Based Remote Sensing Systems  

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

342

Physiological characteristics of cold acclimatization in man  

Microsoft Academic Search

Studies were conducted on 15 healthy young soldiers to evaluate the effect of a cold acclimatization schedule on the thermoregulatory and metabolic activity on exposure to acute cold stress. These men were exposed to cold (10‡C) for 4 h daily wearing only shorts for 21 days, in a cold chamber. They were subjected to a standard cold test at 10

Lazar Mathew; S. S. Purkayastha; A. Jayashankar; H. S. Nayar

1981-01-01

343

Cold Urticaria and Celiac Disease  

Microsoft Academic Search

? Abstract Cold urticaria can be associated with blood and thyroid disorders, drugs, or infections. Celiac disease is an autoimmune enteropathy caused by permanent gluten intolerance. It is often associated with other autoimmune diseases, such as chronic idiopathic urticaria. Nevertheless, association with cold urticaria has not yet been described. A boy aged 3 years 8 months presented local urticaria-angioedema when

M Pedrosa Delgado; F Martín Muñoz; I Polanco Allué; M Martín Esteban

344

COLD STORAGE DESIGN REFRIGERATION EQUIPMENT  

E-print Network

of each section-1 This leaflet is part one of a series of five to be prepared within the broader overallCOLD STORAGE DESIGN AND REFRIGERATION EQUIPMENT REFRIGERATION OF FISH - PART 1 \\ "..\\- ,,, T I Fishery Leaflet 427 Washington 25, D. C. June 1956 REFRIGERATION OF FISH - PART em; COlD STORAGE DESIGN

345

Aerodynamics inside a rapid compression machine  

SciTech Connect

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

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

2006-04-15

346

NINJA: a noninvasive framework for internal computer security hardening  

NASA Astrophysics Data System (ADS)

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

Allen, Thomas G.; Thomson, Steve

2004-07-01

347

Cold Science article  

NSDL National Science Digital Library

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

348

Waste tyre rubberized concrete: properties at fresh and hardened state.  

PubMed

The main objective of this paper is to investigate the properties of various concrete mixtures at fresh and hardened state, obtained by a partial substitution of coarse and fine aggregate with different volume percentages of waste tyres rubber particles, having the same dimensions of the replaced aggregate. Workability, unit weight, compressive and flexural strength and post-cracking behaviour were evaluated and a comparison of the results for the different rubcrete mixtures were proposed in order to define the better mix proportions in terms of mechanical properties of the rubberized concrete. Results showed in this paper were also compared to data reported in literature. Moreover, a preliminary geometrical, physical and mechanical characterization on scrap tyre rubber shreds was made. The rubberized concrete mixtures showed lower unit weight compared to plain concrete and good workability. The results of compressive and flexural tests indicated a larger reduction of mechanical properties of rubcrete when replacing coarse aggregate rather than fine aggregate. On the other hand, the post-cracking behaviour of rubberized concrete was positively affected by the substitution of coarse aggregate with rubber shreds, showing a good energy absorption and ductility indexes in the range observed for fibrous concrete, as suggested by standard (ASTM C1018-97, 1997). PMID:20207128

Aiello, M A; Leuzzi, F

2010-01-01

349

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

350

Hardening by bubbles in He-implanted Ni  

SciTech Connect

Detailed finite-element modeling of nanoindentation data is used to obtain the mechanical properties of Ni implanted with 1-10 at. % He. The mechanical properties of this material elucidate the fundamental materials science of dislocation pinning by nanometer-size gas bubbles and also have implications for radiation damage of materials. Cross-section transmission electron microscopy showed that implantation of 1-5 at. % He at room temperature or at 200 deg. C produced a highly damaged layer extending to a depth of 700-800 nm and containing a fine dispersion of He bubbles with diameters of 1.1{+-}0.2 nm. Implantation at 500 deg. C enlarged the bubble sizes. By fitting the nanoindentation data with a finite-element model that includes the responses of both the implanted layer and the unimplanted substrate in the deformation, the Ni(He) layers are shown to have hardnesses as much as approximately seven times that of untreated Ni, up to 8.3{+-}0.6 GPa. Examination of the dependence of yield strength on He concentration, bubble size, and bubble density reveals that an Orowan hardening mechanism is likely to be in operation, indicating that the bubbles pin dislocation motion as strongly as hard second-phase precipitates do. This strong pinning of dislocations by bubbles is also supported by our numerical simulations, which show that substantial applied shear stress is required to move a dislocation through an empty cavity.

Knapp, J. A.; Follstaedt, D. M.; Myers, S. M. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1056 (United States)

2008-01-01

351

Spectroscopic investigation of Ni speciation in hardened cement paste.  

PubMed

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

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

2006-04-01

352

Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

353

Radiation hardening effects on localized deformation and stress corrosion cracking of stainless steels.  

National Technical Information Service (NTIS)

Radiation hardening in austenitic stainless steels modifies deformation characteristics and correlate well with increased susceptibility to intergranular stress corrosion cracking (IGSCC). Available data on neutron-irradiated materials have been analyzed ...

S. M. Bruemmer, J. I. Cole, J. L. Brimhall, R. D. Carter, G. S. Was

1993-01-01

354

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

355

Preliminary Investigations of the Hardening Qualities of Desulphurization Products. The Desulphurization Product Stabilized.  

National Technical Information Service (NTIS)

In order to prove the hypothesis that hardening of a desulphurization product containing fly ash is a thermal activated process which follows the Arrhenius equation, this report investigates the possibility of carrying out accelerated testing as it is kno...

J. L. Soerensen, N. Foged, P. Henriksen, K. Gram Jeppesen

1986-01-01

356

Cold Fronts in CDM clusters  

E-print Network

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM), if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter (CDM) models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging sub-cluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the amplitude of gas density and temperature gradients across the front. Our results indicate that cold fronts are non-equilibrium transient phenomena and can be observed for a period of less than a billion years. We show that the velocity and density fields of gas surrounding the cold front can be very irregular which would complicate analyses aiming to put constraints on the physical conditions of the intracluster medium in the vicinity of the front.

Daisuke Nagai; Andrey V. Kravtsov

2002-06-26

357

Improved impact toughness of 13Cr martensitic stainless steel hardened by laser  

Microsoft Academic Search

The impact toughness of AISI 403 martensitic stainless steel plate and laser-hardened specimens tempered at various temperatures\\u000a were examined. Phosphorus was the primary residual impurity responsible for tempered embrittlement of this alloy. The experimental\\u000a result also indicated that AISI 403 stainless steel was very sensitive to reverse-temper embrittlement. The improved impact\\u000a toughness of the laser-hardened specimen was attributed to the

L. W. Tsay; Y. M. Chang; S. Torng; H. C. Wu

2002-01-01

358

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

359

Mechanical behavior and hardening characteristics of a superplastic Ti6AI4V alloy  

Microsoft Academic Search

The deformation behavior of a superplastic Ti-6A1-4V alloy at 927C has been characterized by means of constant strain-rate\\u000a tensile tests up to large plastic strain. Significant hardening has been recorded in the course of deformation. Microstructural\\u000a studies on deformed samples indicate the occurrence of simultaneous strain-rate induced grain growth, which explains nearly\\u000a all of the hardening. A small amount of

A. K. Ghosh; C. H. Hamilton

1979-01-01

360

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

NASA Technical Reports Server (NTRS)

NASA's Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the requirements of NASA's Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year.

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

2008-01-01

361

Cyclic plastic behavior analysis based on the micromorphic mixed hardening plasticity model  

Microsoft Academic Search

In this paper, a small strain micromorphic elasto-plastic model with isotropic\\/kinematic hardening is presented for modeling the size effect and Bauschinger effect in material with microstructure. A nonlinear kinematic hardening model is embedded into the micromorphic framework by employing a backstress, a micro-backstress and a micro-couple-backstress in a physical way. The material intrinsic length scale is introduced in the constitutive

Z. H. Zhang; Z. Zhuang; Y. Gao; Z. L. Liu; J. F. Nie

2011-01-01

362

Non-proportionally multiaxial ratcheting of cyclic hardening materials at elevated temperatures: Experiments and simulations  

Microsoft Academic Search

The uniaxial and non-proportionally multiaxial ratcheting behaviors of cyclic hardening materials at room and elevated temperatures were studied by experiments first. As an auxiliary experiment to reveal the cyclic hardening\\/softening feature of the material and determine the material parameters used in the developed model, the material was also tested under a uniaxial and a non-proportionally multiaxial strain cycling. Simultaneously, the

Guozheng Kang; Youguo Li; Qing Gao

2005-01-01

363

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

364

Distinct Hardening Behavior of Ultrafine-Grained Al-Zn-Mg-Cu Alloy  

NASA Astrophysics Data System (ADS)

The age-hardening response for ultrafine-grained, powder-metallurgy-consolidated aluminum 7091 was investigated for the first time. Peak hardening occurred after aging at 353 K (80 °C) for only 4 hours; further aging for up to 26 hours resulted in only slight fluctuations in hardness values. After the 4-hour aging, the precipitate population consists of a high density of nanoscale GP zones (diameter ~3 nm) and nanoscale ?' phase (<30 nm); ? phase is not present.

Ma, Kaka; Smith, Thale; Hu, Tao; Topping, Troy D.; Lavernia, Enrique J.; Schoenung, Julie M.

2014-10-01

365

Influence of shot peening on the fatigue life of laser hardened 17-4PH steel  

Microsoft Academic Search

In order to improve the fatigue life of 17-4PH steel after laser hardening treatment, shot peening and dual shot peening treatments were performed on laser hardened 17-4PH steel in this paper. Characteristic changes of the roughness, hardness and residual stress distribution in three typical areas were discussed in order to gain a better understanding about the shot peening influence on

Zhou Wang; Chuanhai Jiang; Xiaoyan Gan; Yanhua Chen; Vincent Ji

2011-01-01

366

Solution-focused therapy and psychosocial adjustment to orthopedic rehabilitation in a work hardening program  

Microsoft Academic Search

Orthopedic rehabilitation programs utilizing a multidisciplinary approach invite a greater appreciation for the factors which\\u000a influence the recovery process. This study evaluated variables associated with the psychosocial adjustment of work hardening\\u000a program participants when exposed to Solution-Focused psychotherapy. Orthopedic patients receiving workers’ compensation were\\u000a engaged in a work hardening program in which they received either Solution-Focused therapy or the standard

Jack T. Cockburn; Frank N. Thomas; Orbie J. Cockburn

1997-01-01

367

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

PubMed

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

Bouaziz, O; Barbier, D

2012-11-01

368

Matrix design for pseudo-strain-hardening fibre reinforced cementitious composites  

Microsoft Academic Search

Pseudo-strain-hardening behaviour under direct tensile loading in short fibre reinforced cement composites designed with quantitative\\u000a guidance from micromechanics has been demonstrated experimentally, and conditions for the ductile behaviour of such engineered\\u000a cementitious composites (ECC) have been formulated theoretically. In this paper special focus is placed on the influence of\\u000a matrix properties on composite pseudo-strain-hardening. An experimental program is undertaken to

Victor C. Li; Dhanada K. Mishra; Hwai-Chung Wu

1995-01-01

369

Electrical characterization of a radiation-hardened silicon pixel design for CMS  

Microsoft Academic Search

We have summarized our R&D on the radiation hardening and handling of high operating voltage for the CMS forward pixel detectors. More radiation-hardened silicon pixel sensors of configuration n+\\/n\\/p+ with single-sided multi-guard ring structures have been developed and tested under the radiation environment expected at LHC. In the design, no guard ring is required on the n+ side and guard

X. B Xie; H. S Cho; G. W Liang; W Huang; Z Li; C. Y Chien

2002-01-01

370

Assessment of depth of case-hardening in steel rods by electromagnetic methods  

Microsoft Academic Search

Case depth measurements of surface hardened steel parts are important for quality control. The magnetic properties, including initial permeability, differential permeability and saturation\\u000amagnetization of a series of induction-hardened and carburized steel rods were studied through measurements, with the aim of developing new methods to evaluate the case depth\\u000anondestructively. Four-point alternating current potential drop (ACPD) method also has the

Chongxue Zhang

2009-01-01

371

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

372

Versatile cold atom target apparatus.  

PubMed

We report on a compact and transportable apparatus that consists of a cold atomic target at the center of a high resolution recoil ion momentum spectrometer. Cold rubidium atoms serve as a target which can be operated in three different modes: in continuous mode, consisting of a cold atom beam generated by a two-dimensional magneto-optical trap, in normal mode in which the atoms from the beam are trapped in a three-dimensional magneto-optical trap (3D MOT), and in high density mode in which the 3D MOT is operated in dark spontaneous optical trap configuration. The targets are characterized using photoionization. PMID:22852676

Götz, Simone; Höltkemeier, Bastian; Hofmann, Christoph S; Litsch, Dominic; DePaola, Brett D; Weidemüller, Matthias

2012-07-01

373

Nonfreezing cold-induced injuries.  

PubMed

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

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

2011-03-01

374

Microscopic mechanism for cold denaturation  

E-print Network

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

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

2007-04-20

375

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

PubMed Central

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

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

2014-01-01

376

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

NASA Astrophysics Data System (ADS)

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

Lee, Chang Wook; De Cooman, Bruno Charles

2014-09-01

377

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

378

Trapping cold molecular hydrogen.  

PubMed

Translationally cold H(2) molecules excited to non-penetrating |M(J)| = 3 Rydberg states of principal quantum number in the range 21-37 have been decelerated and trapped using time-dependent inhomogeneous electric fields. The |M(J)| = 3 Rydberg states were prepared from the X (1)?(+)(u)(v = 0, J = 0) ground state using a resonant three-photon excitation sequence via the B (1)?(+)(u)(v = 3, J = 1) and I (1)?(g) (v = 0, J = 2) intermediate states and circularly polarized laser radiation. The circular polarization of the vacuum ultraviolet radiation used for the B ? X transition was generated by resonance-enhanced four-wave mixing in xenon and the degree of circular polarization was determined to be 96%. To analyse the deceleration and trapping experiments, the Stark effect in Rydberg states of molecular hydrogen was calculated using a matrix diagonalization procedure similar to that presented by Yamakita et al., J. Chem. Phys., 2004, 121, 1419. Particular attention was given to the prediction of zero-field positions of low-l states and of avoided crossings between Rydberg-Stark states with different values of |M(J)|. The calculated Stark maps and probabilities for diabatic traversal of the avoided crossings were used as input to Monte-Carlo particle-trajectory simulations. These simulations provide a quantitatively satisfactory description of the experimental data and demonstrate that particle loss caused by adiabatic traversals of avoided crossings between adjacent |M(J)| = 3 Stark states of H(2) is small at principal quantum numbers beyond n = 25. The main source of trap losses was found to be from collisional processes. Predissociation following the absorption of blackbody radiation is estimated to be the second most important trap-loss mechanism at room temperature, and trap loss by spontaneous emission is negligible under our experimental conditions. PMID:21818497

Seiler, Ch; Hogan, S D; Merkt, F

2011-11-14

379

Prescription Drugs and Cold Medicines  

MedlinePLUS

... Cold Medicines Email Facebook Twitter What is Prescription Drug Abuse: Some medications have psychoactive (mind-altering) properties and, ... Treatment Locator or 1-800-662-HELP . Prescription Drug Abuse Learn what you can do to prevent medicine ...

380

Cold Gas at High Redshift  

E-print Network

We discuss the current observational and theoretical issues concerning cold gas at high redshift and present simulations showing how a number of observational issues can be resolved with planned future instrumentation.

Colin A. Norman; Robert Braun

1995-12-20

381

BAE Systems Radiation Hardened SpaceWire ASIC and Roadmap  

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

382

Cross breeding of Populus and its hybrids for cold resistance  

Microsoft Academic Search

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

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

2005-01-01

383

Antibiotic use for common cold  

Microsoft Academic Search

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

Timothy W. Kenealy; Bruce Arroll

384

Template stripping using cold welding  

Microsoft Academic Search

A method for fabricating ultra-flat template-stripped (TS) metal surfaces on standard silicon\\/silicon-oxide wafers by means of gold cold-welding is presented, and cold-welded template-stripped (CWTS) platinum surfaces are demonstrated as an example. Due to the lack of any adhesives, the final TS metal ``sandwiches'' are fully compatible with all organic solvents, as well as ultra-high vacuum (UHV). The produced CWTS platinum

Jason J. Blackstock; Zhiyong Li; Gun-Young Jung

2004-01-01

385

Cold fusion—Engineering perspectives  

Microsoft Academic Search

Considerable heat was liberated from a palladium-deuterium (Pd-D) system and this was attributed to cold nuclear fusion of deuterium within the palladium lattice.1 The primary source of heat in cold fusion was proposed to be the work-of-fracture of cracks in the Pd electrodes, and the mechanism for crack initiation and propagation was identified as deuterium or hydrogen embrittlement.2 In this

Ali F. AbuTaha

1990-01-01

386

Cold fusion in condensed matter  

Microsoft Academic Search

A model for cold fusion in condensed matter is proposed (cold fusion of deuterons in palladium). It is assumed that the palladium-deuterium system forms an alloy, i.e., it is assumed that Pd ions as well as d\\/sup +\\/ ions are embedded in an uniform background of negative charge (conduction electrons). The model is based on an interaction potential for deuterons

W. Schommers; C. Politis

1989-01-01

387

A study of exposure to cold in cold stores.  

PubMed

Effects of exposure to cold on skin-temperature and thermal sensations of eight experienced men wearing protective clothing, who were working normally in a cold store at sub-zero temperatures of about -27 degrees C, were studied to assess the feasibility of deriving work recovery routines from experiments conducted in the actual working environment. Although the variations in the responses to cold were such that insistence on a rigid pattern of working and recovery times would be unwise, results indicated that exposures of about 40% of the total time available would not make the risk of discomfort unacceptable, under the usual working conditions provided clothing rated at 5 to 6 togs was worn. Whilst individual reactions are important and there was, for example, an inverse relation between the age of the operative and the time spent in the cold, the results showed that the reactions of the working group are equally important. It was evident that the operatives worked together as a group which appeared to arrange the work loads to suit individual members of the group. The dry-bulb temperature of the air was an adequate index of the thermal environment, which was relatively constant so that the stress upon the operatives was assessed by time spent in the cold. Considerable individual variations in response to cold were evident; the hands and feet were found to be particularly vulnerable areas, and in general a significant fall in skin-temperature occurred whilst the operatives worked inside the store. At some time during the study, all operatives experienced discomfort from cold and there appeared to be a definite association between percentage incidence of discomfort and the time spent in the store. The current practice for the setting of work/recovery routines was questioned and suggestions were made following the results of the investigation. PMID:15676498

Williamson, D K; Chrenko, F A; Hamley, E J

1984-03-01

388

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

389

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

PubMed Central

Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by using an in situ transmission electron microscope nanoindentation tool, the direct observation of dynamic work hardening event in nanocrystalline nickel. During strain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded show an increase of yield strength from 1.64 to 2.29?GPa during multiple loading-unloading cycles. This study provides both the evidence to explain the roots of work hardening at small length scales and the insight for future design of ductile nanocrystalline metals. PMID:23320142

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

2013-01-01

390

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

PubMed

Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by using an in situ transmission electron microscope nanoindentation tool, the direct observation of dynamic work hardening event in nanocrystalline nickel. During strain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded show an increase of yield strength from 1.64 to 2.29 GPa during multiple loading-unloading cycles. This study provides both the evidence to explain the roots of work hardening at small length scales and the insight for future design of ductile nanocrystalline metals. PMID:23320142

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

2013-01-01

391

Cold valleys: cluster decay, cold fusion, cold fission-a unifying theory of related phenomena  

Microsoft Academic Search

A unified description of cluster decay as spontaneous emission of clusters like 14C, 24Ne, 28Mg and 32Si in which the residual nucleus is close to the spherical double magic 208Pb nucleus, of cold fusion as the inverse process for the synthesis of first superheavy elements with Z=107, 108 and 109 by colliding 208Pb-projectiles with different targets and of cold fission

W. Greiner; A. Sandulescu

1991-01-01

392

PUBLISHER'S NOTE: Rapid Communications Rapid Communications  

NASA Astrophysics Data System (ADS)

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

Miller, Tom

2009-09-01

393

A mixed hardening rule coupled with Hill48’ yielding function to predict the springback of sheet U-bending  

Microsoft Academic Search

A mixed hardening model has been used to model the Bauschinger effect. This hardening model is based on Lemaitre and Chaboche\\u000a nonlinear kinematic hardening theory to consider cyclic behavior and the Bauschinger effect. Hill’48 yielding criterion is\\u000a used because of the general stress state and relative ease of formulation. The backward Euler return mapping algorithm is\\u000a applied to calculate the

Bingtao Tang; Guoqun Zhao; Zhaoqing Wang

2008-01-01

394

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

PubMed Central

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

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

2007-01-01

395

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

PubMed Central

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

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

2013-01-01

396

Rapid Prototyping: Lessons Learned  

Microsoft Academic Search

Rapid prototyping is a development method that may or may not be e ective in improving software products and process. Assessing the e ectiveness of rapid prototyping requires empirical data. We analyze 39 published and unpublished \\\\real world\\

V. Scott Gordon; James M. Bieman

1995-01-01

397

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

SciTech Connect

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

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

2013-05-20

398

Cold Fronts in CDM clusters  

E-print Network

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM), if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter (CDM) models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging sub-cluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the ...

Nagai, D; Nagai, Daisuke; Kravtsov, Andrey V.

2003-01-01

399

Cold air systems: Sleeping giant  

SciTech Connect

This article describes how cold air systems help owners increase the profits from their buildings by reducing electric costs and improving indoor air quality through lower relative humidity levels. Cold air distribution involves energy savings, cost savings, space savings, greater comfort, cleaner air, thermal storage, tighter ducting, coil redesign, lower relative humidities, retrofitting, and improved indoor air quality (IAQ). It opens a door for architects, engineers, owners, builders, environmentalists, retrofitters, designers, occupants, and manufacturers. Three things have held up cold air's usage: multiple fan-powered boxes that ate up the energy savings of primary fans. Cold air room diffusers that provided inadequate comfort. Condensation from ducts, boxes, and diffusers. Such problems have been largely eliminated through research and development by utilities and manufacturers. New cold air diffusers no longer need fan powered boxes. It has also been found that condensation is not a concern so long as the ducts are located in air conditioned space, such as drop ceilings or central risers, where relative humidity falls quickly during morning startup.

MacCracken, C.D. (Calmac Manufacturing Corp., Englewood, NJ (United States))

1994-04-01

400

Template stripping using cold welding  

NASA Astrophysics Data System (ADS)

A method for fabricating ultra-flat template-stripped (TS) metal surfaces on standard silicon/silicon-oxide wafers by means of gold cold-welding is presented, and cold-welded template-stripped (CWTS) platinum surfaces are demonstrated as an example. Due to the lack of any adhesives, the final TS metal ``sandwiches'' are fully compatible with all organic solvents, as well as ultra-high vacuum (UHV). The produced CWTS platinum surfaces are demonstrated to have the same surface properties-most importantly single-angstrom rms roughness-as previously studied TS platinum. The effectiveness of the cold-welding technique is shown to decrease as a function of time exposed to ambient laboratory conditions after removal from vacuum and prior to pressurized cold-welding. Contact angle measurements demonstrate this decrease to be due to a gradual increase in surface contamination of the evaporated gold layers prior to their being joined by cold-welding. The potential versatility and scalability of the CWTS fabrication process is briefly discussed. .

Blackstock, Jason J.; Li, Zhiyong; Jung, Gun-Young

2004-05-01

401

Mathematical modeling of cold cap  

SciTech Connect

The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional (1D) mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.

Pokorny, Richard; Hrma, Pavel R.

2012-10-13

402

Authigenic Carbonate Constructions From Deep Sea Cold Seeps  

NASA Astrophysics Data System (ADS)

Various examples of authigenic carbonates from modern marine cold seeps have been described worldwide on active or passive continental margins. They may be associated or not with gas hydrates. After a decade of microbiological and geochemical studies, we know that in cold seep marine environments, methane and other hydrocarbon compounds contained in the ascending fluids are oxidized as CO2 by a microbial consortium of sulfate reducing bacteria and methanotrophic archea. The Anaerobic Oxidation of Methane (AOM) represents the main microbial process driving the precipitation of authigenic carbonate crusts and concretions within the subsurface anoxic sediments. This explains why sea floor is often hardened by carbonate constructions at the sites of active methane seepage. The lateral and vertical extensions of these carbonate constructions are controlled by the balance between the intensity of the venting fluid flux and the ability of microbial communities to oxidize methane and to reduce sulfate. At steady state, the microbial filter transforms the totality of the emitted methane and generates carbonate; however, the efficiency of this filter can be counteracted by high methane flux, so that methane can escape in the water column and eventually reach the atmosphere ; numerical modelling of carbonate crust formation has shown that bioturbation and sedimentation rates are also important factors that control fluid and methane flow rates and thus carbonate precipitation at cold seep sites. The carbonate constructions observed at the sea floor exhibit various morphologies : massive to porous crusts, cm to meters thick, forming large pavements or fragmented slabs, circular chimneys, irregular concretions corresponding to cemented bioturbations. These hard substrates are often colonized by fixed organisms as polychaetes, tube-worms, molluscs, as well as by an abundant vagile fauna. The authigenic carbonates represent very useful archives to reconstruct the story of the seep activity. Their mineralogy, geochemical and isotopic compositions depend on the composition of the fluids and thus provide information of the origin of these fluids. It is noteworthy to mention that carbonate minerals are generally dominated by aragonite and Mg-calcite although dolomite and ankerite may become the unique species as in the carbonate chimneys of the Gulf of Cadiz. All cold seep carbonates are characterized by very low ?13C values down to - 60 permil clearly indicating that they were methane-derived products. The lipid biomarkers that are entrapped in the carbonate network provide the complementary information of the composition of the microbial communities that were involved during the diagenetic processes, AOM, sulfate reduction and methanogenesis.

Pierre, C.; Bouloubassi, I.

2008-12-01

403

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

NASA Astrophysics Data System (ADS)

The number of research papers as well as of patents and patent applications on cold spray and cold spray related technologies has grown exponentially in the current decade. This rapid growth of activity brought a tremendous amount of information on this technology in a short period of time. The main motivation for this review is to summarize the rapidly expanding common knowledge on cold spray to help researchers and engineers already or soon to be involved for their future endeavors with this new technology. Cold spray is one of the various names for describing an all-solid-state coating process that uses a high-speed gas jet to accelerate powder particles toward a substrate where they plastically deform and consolidate upon impact. Cold gas dynamic spray, cold spray, kinetic spray, supersonic particle deposition, dynamic metallization or kinetic metallization are all terminologies found in the literature that designate the above-defined coating process. This review on cold spray technology is divided into two parts. In this article, Part I, patents and patent applications related to this process are reviewed, starting from the first few mentions of the idea at the beginning of the 20th century to its practical discovery in Russia in the 1980s and its subsequent occidental development and commercialization. The patent review encompasses Russian and USA patents and patent applications. Part II will review the scientific literature giving a general perspective of the current understanding and capability of this process.

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

2008-12-01

404

COLD-SAT dynamic model  

NASA Technical Reports Server (NTRS)

This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

Adams, Neil S.; Bollenbacher, Gary

1992-01-01

405

Is it a Cold or the Flu? -Know the Difference Signs & Symptoms Cold Flu  

E-print Network

Is it a Cold or the Flu? - Know the Difference Signs & Symptoms Cold Flu Onset Gradual Sudden Fever.rochester.edu/uhs (Check Care for Colds & Flu in "Health Topics.") Centers for Disease Control www.cdc.gov/flu University

Mahon, Bradford Z.

406

Thermal stresses in chemically hardening elastic media with application to the molding process  

NASA Technical Reports Server (NTRS)

A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.

Levitsky, M.; Shaffer, B. W.

1974-01-01

407

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

408

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

NASA Astrophysics Data System (ADS)

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

Dube, R. K.

2008-05-01

409

Strain hardening in bidisperse polymer glasses: Separating the roles of chain orientation and interchain entanglement  

E-print Network

The effects of entanglement and chain orientation on strain hardening in glassy polymers are separated by examining mixtures of chains with different lengths. Simulations show that the orientation of a molecule of a given chain length is the same in monodisperse systems and bidisperse mixtures, even when entangled and unentangled chains are mixed. In addition, the stress in mixtures is equal to the weighted average of the stresses in monodisperse systems. These results indicate that chains contribute independently to strain hardening, that chain orientation is determined by local interactions with the surrounding glass, and that entanglements play at most an indirect role in strain hardening in the range of strains typically studied. We discuss these results in the context of recent microscopic theories.

Robert S. Hoy; Mark O. Robbins

2009-10-06

410

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

PubMed

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

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

2012-11-01

411

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

PubMed

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

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

2013-09-27

412

Antihydrogen Formation using Cold Plasmas  

SciTech Connect

Antihydrogen, the antimatter counterpart of the hydrogen atom, can be formed by mixing cold samples of antiprotons and positrons. In 2002 the ATHENA collaboration succeeded in the first production of cold antihydrogen. By observing and imaging the annihilation products of the neutral, non-confined, antihydrogen atoms annihilating on the walls of the trap we can observe the production in quasi-real-time and study the dynamics of the formation mechanism. The formation mechanism strongly influences the final state of the formed antihydrogen atoms, important for future spectroscopic comparison with hydrogen. This paper briefly summarizes the current understanding of the antihydrogen formation in ATHENA.

Madsen, N.; Bowe, P.D.; Hangst, J.S. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, I-16146 Genova (Italy); Amsler, C.; Johnson, I.; Pruys, H.; Regenfus, C. [Physik-Institut, Zuerich University, CH-8057 Zurich (Switzerland); Bonomi, G.; Bouchta, A.; Doser, M.; Kellerbauer, A.; Landua, R. [PH Department, CERN, Geneva (Switzerland); Cesar, C.L. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21945-970 (Brazil); Charlton, M.; Joergensen, L.V. [Department of Physics, University of Wales Swansea, Swansea SA2 8PP (United Kingdom)] [and others

2004-10-20

413

Cold induction of Arabidopsis CBF genes involves multiple ICE (inducer of CBF expression) promoter elements and a cold-regulatory circuit that is desensitized by low temperature.  

PubMed

The Arabidopsis CBF1, 2, and 3 genes (also known as DREB1b, c, and a, respectively) encode transcriptional activators that have a central role in cold tolerance. CBF1-3 are rapidly induced upon exposing plants to low temperature, followed by expression of CBF-targeted genes, the CBF regulon, resulting in an increase in plant freezing tolerance. At present, little is known about the cold-sensing mechanism that controls CBF expression. Results presented here indicate that this mechanism does not require a cold shock to bring about the accumulation of CBF transcripts, but instead, absolute temperature is monitored with a greater degree of input, i.e. lower temperature, resulting in a greater output, i.e. higher levels of CBF transcripts. Temperature-shift experiments also indicate that the cold-sensing mechanism becomes desensitized to a given low temperature, such as 4 degrees C, and that resensitization to that temperature requires between 8 and 24 h at warm temperature. Gene fusion experiments identified a 125-bp section of the CBF2 promoter that is sufficient to impart cold-responsive gene expression. Mutational analysis of this cold-responsive region identified two promoter segments that work in concert to impart robust cold-regulated gene expression. These sequences, designated ICEr1 and ICEr2 (induction of CBF expression region 1 or 2), were also shown to stimulate transcription in response to mechanical agitation and the protein synthesis inhibitor, cycloheximide. PMID:14500791

Zarka, Daniel G; Vogel, Jonathan T; Cook, Daniel; Thomashow, Michael F

2003-10-01

414

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

SciTech Connect

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

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

2007-04-23

415

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

416

Magnetic Nondestructive Characterization of Case Depth in Surface-Hardened Steel Components  

NASA Astrophysics Data System (ADS)

The magnetic hysteresis properties and Barkhausen effect signals in a series of induction hardened steel rods were studied through measurements and model simulations, with the objective of developing the measurement techniques for nondestructive evaluation of case depth. It was inferred from the measured hysteresis loop that magnetization reversal proceeded in two stages which took place in the core and the case of the hardened rods. The case depths of the samples were estimated by considering the hysteresis loops as a weighed sum of signals from the case and the core. The results were in good agreement with the nominal case depths determined from the hardness depth profiles.

Lo, C. C. H.; Kinser, E. R.; Melikhov, Y.; Jiles, D. C.

2006-03-01

417

Radiation hardening of components and systems for nuclear rocket vehicle applications  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

418

Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy  

NASA Astrophysics Data System (ADS)

In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

Ghosh, S. K.

2014-09-01

419

The Mode of Deformation in a Cold-Swaged Multifunctional Ti-Nb-Ta-Zr-O Alloy  

NASA Astrophysics Data System (ADS)

Multifunctional titanium alloys, termed Gum Metal™, are ?-phase Ti alloys first developed in 2003. These alloys exhibit many interesting properties including, for example, low rate of work-hardening and superplasticity during cold deformation. The original report described a new plastic deformation mechanism not involving major dislocation activity to explain such deformation behavior. In the current study, a comparable Ti-36.8Nb-2.7Zr-2.0Ta-0.44O (wt pct) alloy to the original investigators was produced by powder sintering, hot forging, solution treatment, and cold swaging with the aim at investigating the microstructural development during swaging. XRD and TEM showed that the forged/solution-treated alloy was ?-phase with a small amount of ?-phase. After cold swaging by up to 96 pct area reduction, TEM/HRTEM revealed the existence of dislocations, deformation twins, ?-phase, nanodisturbances, and lattice bending, with EBSD showing the grains to be highly elongated in the swaging direction, fragmented, and distorted. Most notably, swaging also generated a strong <110> fiber texture, even after moderate strains. The foregoing structural analysis provides substantial evidence that dislocations are present in the alloy after cold swaging. The major support of dislocation glide processes acting as the dominant plastic deformation mode in the swaged alloy is the strong <110> fiber texture that develops, which is a characteristic feature of all cold-drawn/swaged body centered cubic metals and alloys.

Guo, W.; Quadir, M. Z.; Ferry, M.

2013-05-01

420

Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy  

NASA Astrophysics Data System (ADS)

In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

Ghosh, S. K.

2014-10-01

421

Rapidly solidified titanium alloys by melt overflow  

NASA Technical Reports Server (NTRS)

A pilot plant scale furnace was designed and constructed for casting titanium alloy strips. The furnace combines plasma arc skull melting techniques with melt overflow rapid solidification technology. A mathematical model of the melting and casting process was developed. The furnace cast strip of a suitable length and width for use with honeycomb structures. Titanium alloys Ti-6Al-4V and Ti-14Al-21 Nb were successfully cast into strips. The strips were evaluated by optical metallography, microhardness measurements, chemical analysis, and cold rolling.

Gaspar, Thomas A.; Bruce, Thomas J., Jr.; Hackman, Lloyd E.; Brasmer, Susan E.; Dantzig, Jonathan A.; Baeslack, William A., III

1989-01-01

422

Avionics Box Cold Plate Damage Prevention  

NASA Technical Reports Server (NTRS)

Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

2012-01-01

423

Method of manufacturing metallic products such as sheet by cold working and flash anealing  

DOEpatents

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

Hajaligol, Mohammad R. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

2001-01-01

424

Method of manufacturing metallic products such as sheet by cold working and flash annealing  

DOEpatents

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

Hajaligol, Mohammad R. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

2000-01-01

425

Electrochemical characterisation of fuel cell stack during cold start  

NASA Astrophysics Data System (ADS)

Fuel cell self start at negative temperature conditions is not an easy task due to the water produced by the reduction of oxygen at the cathode. This amount of water can turn into ice and block the reaction before the temperature inside the fuel cell reaches positive values. The mechanism of the physical process which leads to oxidant starvation phenomena when ice appears is not yet well identified. In order to obtain a deeper understanding of this problem, the article presents some experimental investigations conducted on a short fuel cell stack. These experiments simulate vehicle technology operated in cold start conditions not with the primary objective to reach a successful and rapid start-up but much rather to characterise and understand the cold start phenomena until starvation occurs. A number of polarisation curves, electrochemical spectroscopy and cyclic voltammetry measurements are done on the stack before, after and also during the cold starts experiments. It is observed that the process of drying and cooling down prior to cold start have a great impact on the electrochemical cathode area. The results obtained show the evolution of the stack behaviour during the low temperature operation with a slow production of frost. The consequence on the individual cells in terms of inhomogeneous degradation is highlighted.

Harel, F.; Bégot, S.; Wasterlain, S.; Candusso, D.

2011-05-01

426

The effect of microstructural evolution on hardening behavior of type 17-4PH stainless steel in long-term aging at 350 deg. C  

SciTech Connect

The effect of microstructural evolution on hardening behavior of 17-4PH stainless steel in long-term aging at 350 deg. C was studied by X-ray diffraction and transmission electron microscopy. The results showed that there is the matrix of lath martensite and nanometer-sized particles of {epsilon}-Cu precipitated from the matrix after the alloy is solution treated and tempered. When the alloy was aged 350 deg. C for 9 months, {alpha}-{alpha}' spinodal decomposition occurred along the grain boundaries and caused an increase in hardness which compensated for the weakening effect due to ripening of the {epsilon}-copper precipitates. Upon further aging to 12 months, the Cr-rich {alpha}'-phase and M{sub 23}C{sub 6} precipitated, both of which strengthened the alloy considerably and led to enhanced hardening despite the continued softening by overaging of the {epsilon}-copper precipitates. With the aging time extended to 15 months, substantial reversed austenite transformed and precipitation of the intermetallic G-phase occurred near the {epsilon}-Cu precipitates in the matrix. The abundant amount of reversed austenite that transformed led to rapid softening.

Wang Jun [School of Materials Science and Engineering, Sichuan University, Chengdu, 610065 (China) and Nuclear Power Institute of China, Chengdu, 610041 (China)]. E-mail: srwangjun@163.com; Zou Hong [Nuclear Power Institute of China, Chengdu, 610041 (China); Li Cong [Nuclear Power Institute of China, Chengdu, 610041 (China); Qiu Shaoyu [Nuclear Power Institute of China, Chengdu, 610041 (China); Shen Baoluo [School of Materials Science and Engineering, Sichuan University, Chengdu, 610065 (China)

2006-12-15

427

Images of the Cold War.  

ERIC Educational Resources Information Center

The conventional U.S. picture traces the Cold War to Soviet violation of wartime agreements, while the U.S.S.R. defends its actions as responses to American violations and foreign adventurism. An understanding of how ideology is shaped by national self-interest will help students see beyond propaganda and myth in interpreting past and current…

Chomsky, Noam

1989-01-01

428

Cold Cloud Cores in Chamaeleon  

NASA Astrophysics Data System (ADS)

The ISOPHOT Serendipity Survey (ISOSS) is a far-infrared survey at 170 mum, using the slewing time of the ISO telescope. It is a powerful tool to explore both, extragalactic sources and objects within the Milky Way. As a first example to investigate the cold interstellar medium in nearby star forming regions, the molecular cloud complexes in Chamaeleon have been studied. The ISOSS coverage of the Chamaeleon region is ~30 %. Combining ISOSS with IRAS data, we derived the density and temperature of the cold interstellar medium. Altogether, 9 very cold cloud cores (VCCs) with colour temperatures of T_dust <= 13 K have been found. Comparing our results with molecular line surveys of the region, and with visual extinction maps, based on NIR starcounts, it shows that: (i) all VCCs have high gas densities, (ii) approx. 80 % have low gas temperatures, (iii) all but one VCC are associated with A_v > 6 mag extinction peaks, and (iv) very cold dust contributes considerably to the total mass of star forming clouds.

Hotzel, S.; Lemke, D.; Stickel, M.; Tóth, L. V.

429

The Cold Blooded Killer: Hypothermia.  

ERIC Educational Resources Information Center

Part of a series of home literacy readers with conversational text and sketches, this booklet depicts the subarctic Alaskan environment where cold makes extreme demands on body metabolism. Body temperature must be maintained above 80F (26.7C). A condition of too little body-heat is termed hypo- ('deficit') thermia ('heat'). Hypothermia is the…

Keller, Rosanne

430

Interface Model of Cold Fusion  

Microsoft Academic Search

The interface theory of cold fusion is a variant of Ion Band State (IBS) Theory.1 It models Bloch symmetry deuterons in a 2-dimensional metal lattice instead of the 3-dimensional metal lattice first used. Both IBS variants recognize that the required lattice symmetry has limited extent, with the reactive deuterons being bound inside a closed volume like a box. The reactive

Talbot A. Chubb

431

Hot, Cold, Fresh and Salty  

NSDL National Science Digital Library

In this activity, learners observe the effects of the layering of warm and cold water and water that is more or less saline than regular water. They will discover how the effects of salinity and temperature are the root cause of thermohaline layering in the ocean.

Roth, Jerry; Service, Noaa O.

432

Cold fusion — The heat mechanism  

Microsoft Academic Search

The assumption that deuterium, and not palladium, is the fuel in the Pons-Fleischmann experiments led to high expectations of cold nuclear fusion. The conversion of mechanical energy to heat was neglected in studying the phenomenon. Considerable strain energy is stored in metals when processed from the ore. The initiation, growth, and propagation of cracks in the bulk disturb the energy

Ali F. AbuTaha

1990-01-01

433

Warming up to cold fusion  

Microsoft Academic Search

The idea that tabletop equipment at room temperature could produce nuclear fusion was widely rejected five years ago by the scientific community. Nevertheless, recent results from numerous labs show that a novel phenomena of some kind may indeed be occurring, though theorist are still groping for an explanation. Many aspects of the cold fusion effect are now reproducible if known

Storms

2009-01-01

434

The status of `cold fusion'  

Microsoft Academic Search

The questions raised by reports of nuclear reactions at low energies, so called `cold fusion', are not yet answered to the satisfaction of many scientists. Further experimental investigations of these and related questions seems desirable, at least for scientific if not practical reasons. Properly conducted, such investigations would be indistinguishable from normal research. They would yield information germane to accepted

David J. Nagel

1998-01-01

435

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

Microsoft Academic Search

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

E. Diegele; W. Jansohn; Ch. Tsakmakis

436

Enhanced fatigue resistance of a nickel-based hastelloy induced by a surface nanocrystallization and hardening process  

Microsoft Academic Search

Improvements in the fatigue resistance of a nickel-based alloy have been achieved via a surface nanocrystallization and hardening (SNH) process. The enhanced fatigue resistance is related to the surface nanocrystallization, work hardening, and compressive residual stresses induced by the SNH process.

J. C. Villegas; L. L. Shaw; K. Dai; W. Yuan; J. Tian; P. K. Liaw; D. L. Klarstrom

2005-01-01

437

Application of corotational rates of the logarithmic strain in constitutive modeling of hardening materials at finite deformations  

Microsoft Academic Search

In this paper a finite deformation constitutive model for rigid plastic hardening materials based on the logarithmic strain tensor is introduced. The flow rule of this constitutive model relates the corotational rate of the logarithmic strain tensor to the difference of the deviatoric Cauchy stress and the back stress tensors. The evolution equation for the kinematic hardening of this model

R. Naghdabadi; M. Yeganeh; A. R. Saidi

2005-01-01

438

Effect of texture and microstructure on strain hardening anisotropy for aluminum deformed in uniaxial tension and simple shear  

Microsoft Academic Search

Uniaxial and simple shear stress–strain curves were obtained for a 1050-O aluminum alloy sheet sample in different specimen orientations with respect to the material symmetry axes. For uniaxial tension, a strong anisotropy of strain hardening was observed leading to about 30% difference in uniform tensile elongation between the extreme conditions. For simple shear, the hardening was also significantly different. These

A. B. Lopes; F. Barlat; J. J. Gracio; J. F. Ferreira Duarte; E. F. Rauch

2003-01-01

439

Evaluation of wear-induced material loss in case-hardened steel using magnetic Barkhausen emission measurement  

Microsoft Academic Search

The feasibility of using magnetic Barkhausen emission (MBE) measurement for the evaluation of wear-induced material loss in case-hardened steel is examined in this paper. MBE measurements were carried out on two case hardened carburized steel disks. The MBE signals from the carburized material were significantly different from the base metal. On both disks it was observed that the MBE level

B. Zhu; M. J. Johnson; D. C. Jiles

2000-01-01

440

Complex phytohormone responses during the cold acclimation of two wheat cultivars differing in cold tolerance, winter Samanta and spring Sandra.  

PubMed

Hormonal changes accompanying the cold stress (4°C) response that are related to the level of frost tolerance (FT; measured as LT50) and the content of the most abundant dehydrin, WCS120, were compared in the leaves and crowns of the winter wheat (Triticum aestivum L.) cv. Samanta and the spring wheat cv. Sandra. The characteristic feature of the alarm phase (1 day) response was a rapid elevation of abscisic acid (ABA) and an increase of protective proteins (dehydrin WCS120). This response was faster and stronger in winter wheat, where it coincided with the downregulation of bioactive cytokinins and auxin as well as enhanced deactivation of gibberellins, indicating rapid suppression of growth. Next, the ethylene precursor aminocyclopropane carboxylic acid was quickly upregulated. After 3-7 days of cold exposure, plant adaptation to the low temperature was correlated with a decrease in ABA and elevation of growth-promoting hormones (cytokinins, auxin and gibberellins). The content of other stress hormones, i.e., salicylic acid and jasmonic acid, also began to increase. After prolonged cold exposure (21 days), a resistance phase occurred. The winter cultivar exhibited substantially enhanced FT, which was associated with a decline in bioactive cytokinins and auxin. The inability of the spring cultivar to further increase its FT was correlated with maintenance of a relatively higher cytokinin and auxin content, which was achieved during the acclimation period. PMID:22304971

Kosová, Klára; Prášil, Ilja Tom; Vítámvás, Pavel; Dobrev, Petre; Motyka, Václav; Floková, Kristýna; Novák, Ond?ej; Ture?ková, Veronika; Rol?ik, Jakub; Pešek, Bed?ich; Trávni?ková, Alena; Gaudinová, Alena; Galiba, Gabor; Janda, Tibor; Vlasáková, Eva; Prášilová, Pavla; Vanková, Radomíra

2012-04-15

441

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

442

Cold Weather Guidelines Temperature check-in  

E-print Network

respiratory injury, including 'exercise induced' asthma and increased respiratory infection. For your. The temperature cut-off we have set is to minimize cold weather injuries both with frost bite and cold induced

Scheel, David

443

Cold-Weather Sports and Your Family  

MedlinePLUS

... the weather turns frosty. Beating the Cold-Weather Blahs Once a chill is in the air, our ... more sedentary can lead to the "cold-weather blahs." Kids might feel more tired, lethargic, or even ...

444

Helium Find Thaws the Cold Fusion Trail.  

ERIC Educational Resources Information Center

Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

Pennisi, E.

1991-01-01

445

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2010 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2010-04-01

446

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2011 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2011-04-01

447

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2012 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2012-04-01

448

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2013-04-01

449

Rapid treatment of rhinophyma with powered microdebrider.  

PubMed

We describe here our experience in using sinus microdebrider to rapidly debulk and sculpt the tissues in cases of rhinophyma correction. We utilized the use of the 4?mm M4 Rotatable Cutting Straight Sinus Blade on a straight Straightshot M4 Microdebrider by Medtronic at 800 rpm oscillation which is normally utilised in our sinus surgery practice. The microdebrider is straightforward to use and is already stocked in most ENT departments. It requires no additional training or cost outlay for departments that perform endoscopic sinus surgery with microdebrider. In our experience it affords the surgeon the ability to rapidly and accurately sculpt the nose to an excellent aesthetic result. We feel it is a more precise tool than cold steel or Bovie cautery, quicker than CO2 laser techniques, and avoids the aerosol of dermabrasion. No complications occurred in our series, and all patients rated their cosmetic outcome as good to excellent. PMID:23509654

Faris, C; Manjaly, J G; Ismail-Koch, H; Caldera, S

2013-01-01

450

Rapid Treatment of Rhinophyma with Powered Microdebrider  

PubMed Central

We describe here our experience in using sinus microdebrider to rapidly debulk and sculpt the tissues in cases of rhinophyma correction. We utilized the use of the 4?mm M4 Rotatable Cutting Straight Sinus Blade on a straight Straightshot M4 Microdebrider by Medtronic at 800 rpm oscillation which is normally utilised in our sinus surgery practice. The microdebrider is straightforward to use and is already stocked in most ENT departments. It requires no additional training or cost outlay for departments that perform endoscopic sinus surgery with microdebrider. In our experience it affords the surgeon the ability to rapidly and accurately sculpt the nose to an excellent aesthetic result. We feel it is a more precise tool than cold steel or Bovie cautery, quicker than CO2 laser techniques, and avoids the aerosol of dermabrasion. No complications occurred in our series, and all patients rated their cosmetic outcome as good to excellent. PMID:23509654

Faris, C.; Manjaly, J. G.; Ismail-Koch, H.; Caldera, S.

2013-01-01

451

Cold atom Raman spectrography using velocity-selective resonances.  

PubMed

We have studied velocity-selective resonances in the presence of a uniform magnetic field and shown how they can be used for rapid, single-shot assessment of the ground state magnetic sublevel spectrum in a cold atomic vapor. Cold atoms are released from a magneto-optical trap in the presence of a small bias magnetic field ( approximately 300 mG) and exposed to a laser field comprised of two phase-locked counterpropagating beams connecting the two ground state hyperfine manifolds. An image of the expanded cloud shows the velocity-selected resonances as distinct features, each corresponding to specific magnetic sublevel, in a direct, intuitive manner. We demonstrate the technique with both 87Rb and 85Rb, and show the utility of the technique by optically pumping into particular magnetic sublevels. The results are shown to agree with a theoretical model, and are compared to traditional Raman spectroscopy. PMID:19654701

Fatemi, Fredrik K; Terraciano, Matthew L; Bashkansky, Mark; Dutton, Zachary

2009-07-20

452

Optomechanical self-structuring in a cold atomic gas  

NASA Astrophysics Data System (ADS)

The rapidly developing field of optomechanics aims at the combined control of optical and mechanical modes. In cold atoms, the spontaneous emergence of spatial structures due to optomechanical back-action has been observed in one dimension in optical cavities or highly anisotropic samples. Extensions to higher dimensions that aim to exploit multimode configurations have been suggested theoretically. Here, we describe a simple experiment with many spatial degrees of freedom, in which two continuous symmetries--rotation and translation in the plane orthogonal to a pump beam axis--are spontaneously broken. We observe the simultaneous long-range spatial structuring (with hexagonal symmetry) of the density of a cold atomic cloud and of the pump optical field, with adjustable length scale. Being based on coherent phenomena (diffraction and the dipole force), this scheme can potentially be extended to quantum degenerate gases.

Labeyrie, G.; Tesio, E.; Gomes, P. M.; Oppo, G.-L.; Firth, W. J.; Robb, G. R. M.; Arnold, A. S.; Kaiser, R.; Ackemann, T.

2014-04-01

453

Cold Fusion Has Now Come Out of the Cold  

Microsoft Academic Search

The phenomenon called cold fusion or LENR (Low-Energy-Nuclear-Reaction) has now achieved a level of reproducibility and understanding that warrants re-examination of the claims. A summary of what is known and want is being done worldwide to obtain more knowledge will be given. Rather than disappearing as better data are obtained, the effects are becoming more reproducible and of greater magnitude.

Edmund Storms

2003-01-01

454

The cold equation of state of tantalum  

SciTech Connect

In high-pressure isentropic compression experiments (ICE), the pressure is dominated by the cold curve. In order to obtain an accurate semi-empirical cold curve for Ta, we calculate the thermal pressure from ab initio phonon and electronic excitation spectra. The cold curve is then inferred from ultrasonic and shock data. Our empirical cold pressure is compared to density functional calculations and found to be closer to GGA results at low pressure and to approach LDA at high pressure.

Greeff, Carl W [Los Alamos National Laboratory; Rudin, Sven P [Los Alamos National Laboratory; Corckett, Scott D [Los Alamos National Laboratory; Wills, John M [Los Alamos National Laboratory

2009-01-01

455

Genetic control of plant resistance to cold  

Microsoft Academic Search

Data on the main pathways of the effect of cold on plants and on the pathways of plant responses to cold stress are reviewed.\\u000a Genes involved in these processes are described. Special attention is given to transcription factors regulating expression\\u000a of cold resistance genes. In addition, the participation of hormones and metabolites in the protection of plants from cold-induced\\u000a damage

A. S. Kurbidaeva; M. G. Novokreshchenova

2011-01-01

456

Laser hardening of AISI 52100 bearing steel with a discrete fiber laser spot  

NASA Astrophysics Data System (ADS)

Surface hardening with discrete laser spot treatment is an interesting solution since the adoption of a single pulse allows the treatment of different surface geometries avoiding the effect of back tempering. The aim of this work is to find a suitable process window in which operate to get best results in terms of hardness, diameter and depth of the treated region. A single pulse out of a fiber laser source impinging on a bearing hypereutectoid steel was used using different power values, pulse energy and defocussing distances, in order to get the optimal process parameters. The dimensions of the hardened zone and its hardness were then acquired and related to the laser process parameters, to the prior microstructure of the steel (spheroidized and tempered after oil quenching) and to the roughness on the specimen before the laser treatment. Experimental results highlighted that both the surface condition (in terms of roughness) and the initial steel microstructure have a great influence on the achieved hardness values and on the dimension of the laser hardened layer. The pulse energy and power strongly affected the dimension of the hardened layer, too.

Sorgente, Donato; Corizzo, Ottavio; Ancona, Antonio; Scintilla, Leonardo D.; Palumbo, Gianfranco; Tricarico, Luigi

2014-02-01

457

An Experimental Analysis of SEU Sensitiveness on System Knowledge-based Hardening Techniques  

Microsoft Academic Search

Logic Soft Errors caused by radiation are a major concern when working with circuits that need to operate in harsh environments, such as space or avionics applications, where soft errors are traditionally referred as Single Event Effects. In this paper, system knowledge-based hardening techniques using recursive structures for the implementation of moving average filters that provide protection against Single Event

Oscar Ruano; Pilar Reyes; Juan Antonio Maestro; Luca Sterpone; Pedro Reviriego

2007-01-01

458

Solution Hardening and Softening in KCl-KBr Single Crystals at Low Temperatures  

Microsoft Academic Search

The temperature and concentration dependence of the critical resolved shear stress (CRSS) for KCl and KCl-KBr solid solutions was measured from 4.2 K to 293 K. At lower temperatures the solid solutions with the concentration below 10 mol% KBr and above 90 mol% KBr showed solution softening. The other concentrations of solid solutions were hardened at all temperatures tested. The

Toshihiko Kataoka; Teruyoshi Uematsu; Tomoharu Yamada

1978-01-01

459

The Surface Fatigue Life of Contour Induction Hardened AISI 1552 Gears  

NASA Technical Reports Server (NTRS)

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-01-01

460

Investigation of abrasive + erosive wear behaviour of surface hardening methods applied to AISI 1050 steel  

Microsoft Academic Search

In the present technology, machine parts which work at the industry area such as agriculture, mining and cement are subjected to wear. The wear resistance of these parts is improved by conventional heat treatments or surface heat treatments, which only improved the property surface and sub-surface of materials.In this study, samples of AISI 1050 steel are subjected to induction hardening

N. Y. Sari; M. Yilmaz

2006-01-01

461

The surface fatigue life of contour induction hardened AISI 1552 gears  

NASA Astrophysics Data System (ADS)

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-07-01

462

The surface fatigue life of contour induction hardened AISI 1552 gears  

NASA Technical Reports Server (NTRS)

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-01-01

463

The relation between growth cessation and frost hardening in Scots pines of different origins  

Microsoft Academic Search

The cessation of shoot elongation, diameter growth and needle elongation were compared with the initiation of frost hardening of the stems and needles in an 8-year-old provenance trial of Scots pine (Pinus sylvestris L.) established in central Finland. The saplings were of six different origins ranging from Estonia to northern Finland, forming a latitudinal gradient of ca. 10°N. The frost

Tapani Repo; Gang Zhang; Aija Ryyppö; Risto Rikala; Martti Vuorinen

2000-01-01

464

Use of thermally reactive powders for hardening steel and cast iron parts  

Microsoft Academic Search

The problem of surface hardening of working organs of earth-movlng machinery and many parts of tractors and agricultural machines should be dealt with using the least expensive constructional materials and treatments. The inexpensive and nonstrategic mixtures described in this article were first used successfully for the surface alloying of steel castings [I]. The mixtures are thermally reactive, but the thermal

A. A. Zhukov; E. P. Shilina; G. A. Chernaya

1988-01-01

465