scholarly journals The Role of Glide during Creep of Copper at Low Temperatures

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 772 ◽  
Author(s):  
Arash Hosseinzadeh Delandar ◽  
Rolf Sandström ◽  
Pavel Korzhavyi
Keyword(s):  
Low Temperatures ◽  
Spent Nuclear Fuel ◽  
Classical Problem ◽  
Dislocation Dynamics ◽  
Stationary Condition ◽  
Load Drop ◽  
Static Recovery ◽  
Ambient Temperatures ◽  
Loading Direction

Copper canister will be used in Scandinavia for final storage of spent nuclear fuel. The copper will be exposed to temperatures of up to 100 °C. The creep mechanism at near ambient temperatures has been assumed to be glide of dislocations, but this has never been verified for copper or other materials. In particular, no feasible mechanism for glide based static recovery has been proposed. To attack this classical problem, a glide mobility based on the assumption that it is controlled by the climb of the jogs on the dislocations is derived and shown that it is in agreement with observations. With dislocation dynamics (DD) simulations taking glide but not climb into account, it is demonstrated that creep based on glide alone can reach a quasi-stationary condition. This verifies that static recovery can occur just by glide. The DD simulations also show that the internal stress during creep in the loading direction is almost identical to the applied stress also directly after a load drop, which resolves further classical issues.

The Role of the Initiator System in the Synthesis of Acidic Multifunctional Nanoparticles Designed for Molecular Imprinting of Proteins

2020 ◽  
Vol 65 (1) ◽  
pp. 28-41
Author(s):  
Marwa Aly Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horváth
Keyword(s):  
Acrylic Acid ◽  
Binding Affinity ◽  
Molecular Imprinting ◽  
Low Temperatures ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
Multifunctional Nanoparticles ◽  
High Affinity ◽  
Initiator System

Multifunctional nanoparticles have been shown earlier to bind certain proteins with high affinity and the binding affinity could be enhanced by molecular imprinting of the target protein. In this work different initiator systems were used and compared during the synthesis of poly (N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) nanoparticles with respect to their future applicability in molecular imprinting of lysozyme. The decomposition of ammonium persulfate initiator was initiated either thermally at 60 °C or by using redox activators, namely tetramethylethylenediamine or sodium bisulfite at low temperatures. Morphology differences in the resulting nanoparticles have been revealed using scanning electron microscopy and dynamic light scattering. During polymerization the conversion of each monomer was followed in time. Striking differences were demonstrated in the incorporation rate of acrylic acid between the tetramethylethylenediamine catalyzed initiation and the other systems. This led to a completely different nanoparticle microstructure the consequence of which was the distinctly lower lysozyme binding affinity. On the contrary, the use of sodium bisulfite activation resulted in similar nanoparticle structural homogeneity and protein binding affinity as the thermal initiation.

Ambient temperatures, heatwaves and out-of-hospital cardiac arrest in Brisbane, Australia

2021 ◽  
pp. oemed-2020-107018
Author(s):  
Tan N Doan ◽  
Daniel Wilson ◽  
Stephen Rashford ◽  
Emma Bosley
Keyword(s):  
Cardiac Arrest ◽  
Temperature Distribution ◽  
Low Temperatures ◽  
Meteorological Data ◽  
Reference Temperature ◽  
Ambient Temperatures ◽  
Distributed Lag ◽  
Exposure Response ◽  
Heat Threshold ◽  
Hospital Cardiac Arrest

BackgroundThe health impacts of temperatures are gaining attention in Australia and worldwide. While a number of studies have investigated the association of temperatures with the risk of cardiovascular diseases, few examined out-of-hospital cardiac arrest (OHCA) and none have done so in Australia. This study examined the exposure–response relationship between temperatures, including heatwaves and OHCA in Brisbane, Australia.MethodsA quasi-Poisson regression model coupled with a distributed lag non-linear model was employed, using OHCA and meteorological data between 1 January 2007 and 31 December 2019. Reference temperature was chosen to be the temperature of minimum risk (21.4°C). Heatwaves were defined as daily average temperatures at or above a heat threshold (90th, 95th, 98th, 99th percentile of the yearly temperature distribution) for at least two consecutive days.ResultsThe effect of any temperature above the reference temperature was not statistically significant; whereas low temperatures (below reference temperature) increased OHCA risk. The effect of low temperatures was delayed for 1 day, sustained up to 3 days, peaking at 2 days following exposures. Heatwaves significantly increased OHCA risk across the operational definitions. When a threshold of 95th percentile of yearly temperature distribution was used to define heatwaves, OHCA risk increased 1.25 (95% CI 1.04 to 1.50) times. When the heat threshold for defining heatwaves increased to 99th percentile, the relative risk increased to 1.48 (1.11 to 1.96).ConclusionsLow temperatures and defined heatwaves increase OHCA risk. The findings of this study have important public health implications for mitigating strategies aimed at minimising temperature-related OHCA.

The role of Pt in α-MoC on the water-gas shift reaction at low temperatures

Joule ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 521-523
Author(s):  
Tiago J. Goncalves ◽  
Samira Siahrostami
Keyword(s):  
Low Temperatures ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Shift Reaction ◽  
Water Gas

EFFECTS OF LOW FLUCTUATING TEMPERATURES ON FARM ANIMALS.: III. INFLUENCE OF AMBIENT AIR TEMPERATURE ON FEED INTAKE OF LACTATING HOLSTEIN-FRIESIAN COWS

1958 ◽  
Vol 38 (2) ◽  
pp. 148-159 ◽  
Author(s):  
M. A. MacDonald ◽  
J. M. Bell
Keyword(s):  
Milk Production ◽  
Air Temperature ◽  
Low Temperatures ◽  
Ambient Air ◽  
Feed Consumption ◽  
Ambient Temperatures ◽  
Ambient Air Temperature ◽  
Holstein Friesian ◽  
Cent Level ◽  
Friesian Cows

This report presents effects of low temperatures on the feed consumption and efficiency of milk production of six mature, lactating, Holstein-Friesian cows that were confined in stanchions for three fortnightly experimental periods during which ambient temperatures measured in degree-hours per day (d-h/day) ranged from 110 to 1152 and daily minimum ambient air temperature (DMAAT) varied from 0° to 38°F. Applying results obtained, it was calculated that as temperatures decreased, i.e., d-h/day increased from 100 to 1200 and DMAAT decreased from 40° to 0°F, average daily intakes of total dry matter, hay, and gross and digestible Calories increased approximately 6.4 lb., 5.3 lb., 13 Therms and 9 Therms, respectively. Each of these increases was statistically significant at the 1 per cent level. Reductions in temperature also decreased gross and net caloric efficiencies of milk production approximately 10 and 8.5 per cent, respectively. These decreases were significant at the 2 per cent level. No correlation was evident between crude protein utilization and temperature.Results indicated that thermal stress was not overcome adequately by supplementary hay intake alone and that appetite stimulation by low temperatures had a carry-over effect continuing at least 24 hours. For continued efficient milk production during winters where low ambient temperatures are prevalent these results suggest it is necessary to provide some form of building insulation, ambient heat and/or provide a high energy supplement to otherwise adequate production rations.

GDP binding to rat brown fat mitochondria: effects of thyroxine at different ambient temperatures

1981 ◽  
Vol 241 (3) ◽  
pp. C134-C139 ◽  
Author(s):  
U. Sundin
Keyword(s):  
Linear Increase ◽  
Reciprocal Relationship ◽  
Brown Fat ◽  
Hormone Activity ◽  
Ambient Temperatures ◽  
Heating Capacity ◽  
Brown Adipose ◽  
Induced Changes ◽  
Brown Fat Mitochondria

Reports on a reciprocal relationship between sympathetic-nerve and experimentally induced changes in thyroid-hormone activity called into question the proposed role of thyroxine in the changes seen in the brown fat after cold adaptation. Rats reared at +30, +22, and +5 degrees C received daily injections of thyroxine (1 mg/kg). After 3 wk of treatment, the thermogenic state of the tissue was assessed by measuring the capacity of the brown fat mitochondria to bind guanosine 5'-diphosphate (GDP). GDP-inhibited mitochondrial swelling, brown adipose tissue (BAT) wet weights, and mitochondrial yields were also measured. The control animals showed a linear increase in GDP binding between +30 and +5 degrees C. Thyroxine was found to lower the GDP binding markedly at +5 degrees C, less so at +22 degrees C, while no effect was evident at +30 degrees C. The values at +22 and +30 degrees C were identical. The other parameters studied all confirmed these results. The conclusion made is that the thyroxine-induced rise in basal metabolic rate lowers the critical temperature and reduces the demand for nonshivering thermogenesis. This is reflected in the reduced GDP binding and hence heating capacity of the brown fat mitochondria.

scholarly journals ACCUMULATION BEHAVIOUR OF ALLANTOIN IN THE UNDERGROUND PHYTOMASS OF THE BORAGINACEAE FAMILY AND ITS ROLE IN ADAPTING THE PLANTS TO ADVERSE ENVIRONMENTAL FACTORS

2019 ◽  
Vol 14 (1) ◽  
pp. 126-136
Author(s):  
A. Ya. Tamakhina ◽  
A. A. Akhkubekova ◽  
A. B. Ittiev
Keyword(s):  
Solar Radiation ◽  
Sea Level ◽  
Low Temperatures ◽  
High Performance ◽  
Growing Season ◽  
Stress Factors ◽  
Adaptation To Stress ◽  
Plant Adaptation ◽  
The Family

Aim.The aim of the work described herein was to study the dynamics of allantoin accumulation in the underground phytomass ofEchium vulgareL.,Symphytum caucasicumM. Bieb. andS. asperumLepech. as well as to clarify the role of allantoin in plant adaptation to stress factors.Methods.We studied the roots of plants growing in the foothill (Nalchik, 490–512 m above sea level) and the mountain zones of the Kabardino-Balkarian Republic (Terskol village, 2530 m above sea level; Verkhnyaya Balkaria village, 2680 m above sea level). The roots were collected at the stages of rosetting, flowering, fruiting and at the end of the growing season. Aqueous-alcoholic extracts of shredded roots were analyzed by high-performance liquid chromatography.Results.The highest content of allantoin in the roots ofEchium vulgare,Symphytum caucasicum,S. asperumplants was noted at the end of the growing season, respectively 0.915; 0.342–0.658; 2,842–3,426%. Under conditions of low temperatures and increased solar radiation, the content of allantoin in the roots increases 1.2–1.9 times as compared with the plants of the foothill zone.Conclusion.Allantoin plays an important role in the process of adapting species of the family Boraginaceae to oxidative stress caused by hypothermia and increased solar radiation.

scholarly journals Will climate change worsen your health?

2019 ◽  
Author(s):  
Joan Ballester
Keyword(s):  
Public Health ◽  
Policy Making ◽  
Heat Waves ◽  
Research Topic ◽  
Climate Factors ◽  
Social Differences ◽  
Ongoing Research ◽  
Science And Policy ◽  
Ambient Temperatures

Nearly 8% of deaths in Europe are due to ambient temperatures, and global warming represents an additional threat for public health. Despite the fact that we expect more frequent, intense and persistent heat waves during the present century, it is actually not clear whether the number of attributable deaths will also increase. Here I discuss why the role of early adaptation to temperature rise is a major ongoing research topic in science and policy-making, and how these eventual acclimatization processes depend on a myriad of non-climate factors such as the air quality in cities, social differences within and between societies, demographic changes or the evolution of the economy.

Clear band formation simulated by dislocation dynamics: Role of helical turns and pile-ups

2008 ◽  
Vol 380 (1-3) ◽  
pp. 22-29 ◽  
Author(s):  
Thomas Nogaret ◽  
David Rodney ◽  
Marc Fivel ◽  
Christian Robertson
Keyword(s):  
Dislocation Dynamics ◽  
Band Formation ◽  
Clear Band

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

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