Elevated Temperature Research Papers - Academia.edu (original) (raw)

The effects of aging on mechanical behavior of lead free solders have been examined by performing creep tests on four different SAC alloys (SAC105, SAC205, SAC305, SAC405) that were aged for various durations (0-4 months) at room temperature (25degC), and several elevated temperatures (75, 100, and 125 degC). Analogous tests were performed with 63Sn-37Pb eutectic solder samples for comparison purposes. Variations of the creep properties were observed and modeled as a function of aging time and aging temperature. In addition, the chosen selection of SAC alloys has allowed us to explore the effects of silver content on aging behavior.

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- Room Temperature, Elevated Temperature
- by Bahman Tohidi
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- Chemical Engineering, Classical Physics, Fluid phase equilibria, Compositional Data
- by Frank Ritzert
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- Materials Science, Power System, High Temperature, Heat pump

The effect of corrosive solutions on stress relaxation behavior of pure Mg and its alloys is studied. Pure magnesium shows a crucial corrosion stress relaxation in 3.5wt.% NaCl even at room temperature in comparison with tests in air. Die-cast Mg alloys AZ91D, AM50 and AS21 at room temperature show a relatively small stress decrease both in air and in different

- by Emmanuel Gutman
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- Stress relaxation, Magnesium, Dislocations, Grain Boundary

This paper addresses the efficiency of thermal insulation layers applied to protect structural elements strengthened by fiber-reinforced polymers (FRP) in the case of fire event. The paper presents numerical modeling and nonlinear analysis of reinforced concrete (RC) columns externally strengthened by FRP and protected by thermal insulation layers when subjected to elevated temperature specified by standard fire tests, in order to predict their residual capacity and fire endurance. The adopted numerical approach uses commercial software includes heat transfer, variation of thermal and mechanical properties of concrete, steel reinforcement, FRP and insulation material with elevated temperature. The numerical results show good agreement with published results of full-scale fire tests. A parametric study was conducted to investigate the influence of several variables on the structural response and residual capacity of insulated FRP-confined columns loaded by service loads when exposed ...

- by Gehan Hamdy
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- Materials Science, Numerical Modeling, Fire Protection, Finite Elements

An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, β-naphthol and urea or amides, in the presence of potassium dodecatungstocobaltate trihydrate [K5CoW12O40 · 3H2O, (1 mol%)] as a heterogeneous catalyst. The reactions were carried out in 1,2-dichloroethane at room temperature or under solvent-free media at elevated temperature. The present methodology offers several advantages such as excellent yields, simple procedure and the catalyst exhibited remarkable reusability.

- by Srini Kante
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- Chemical Engineering, Catalysis, Molecular, Reaction Time
- by Ahmed I Rushdi
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- Water, Biological Sciences, Fatty acids, Origin of Life

Dehydration/condensation reactions between organic molecules in the prebiotic environment increased the inventory and complexity of organic compounds available for self-assembly into primitive cellular organisms. As a model of such reactions and to demonstrate this principle, we have investigated the esterification reaction between glycerol and decanoic acid that forms glycerol monodecanoate (GMD). This amphiphile enhances robustness of self-assembled membranous structures of carboxylic acids to the potentially disruptive effects of pH, divalent cation binding and osmotic stress. Experimental variables included temperature, water activity and hydrolysis of the resulting ester product, providing insights into the environmental conditions that would favor the formation and stability of this more evolved amphiphile. At temperatures exceeding 50 degrees C, the ester product formed even in the presence of bulk water, suggesting that the reaction occurs at the liquid interface of the two reactants and that the products segregate in the two immiscible layers, thereby reducing hydrolytic back reactions. This implies that esterification reactions were likely to be common in the prebiotic environment as reactants underwent cycles of wetting and drying on rare early landmasses at elevated temperatures.

- by Charles Apel
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- Thermodynamics, Water, Kinetics, Self Assembly
- by David Deamer
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- Mechanical Engineering, Aerospace Engineering, Self Assembly, Space

During the summer heat-wave, poultry breeders find it difficult to maintain appropriate temperatures in poultry facilities, which often exposes the birds to heat stress. Many studies have shown that a change in ambient temperature has a tremendous effect on a number of physiological processes. Elevated air temperatures were found to increase rectal temperature (Acikgoz et al., 2003), change cholesterol levels (Siegel, 1968; Puvadolpirod and Thaxton, 2000 a, b, c) and affect the humoral and cellular immune response (Siegel et al., 1983; Murray et al., 1987 a, b; Puvadolpirod and Thaxton, 2000 a, b, c). Cook et al. (1993) and Miller et al. (1994) report that unsaturated fatty acids stimulate the body’s physiological processes during stress. Whitehead (2000) holds that by stimulating the immune system through modified feeding, it is possible to offset the negative effects of reduced immunity resulting from stress. The aim of the present study was to determine the effect of supplementin...

- by Ewa Sosnówka-Czajka
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- Agronomy, Biology, Agriculture, Heat stress
- by Jaroslaw Drelich
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- Chemical Engineering, Analytical Chemistry, Soft Drinks, Contact angle
- by M. Al-marhoun
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- High Temperature, Thermal Stability, Elevated Temperature, Pressure Effect
- by Roger Plank
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- Civil Engineering, Rotation Curve, Elevated Temperature
- by Jay Benziger
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- Engineering, Chemistry, Materials Chemistry, PEM fuel cell

Two different Calanus finmarchicus (Gunnerus) cohorts originating from 60°N (Bergen) and 69°N (Tromsø) were investigated in equal environmental conditions to study their different physiological responses to the same environment. A two-plus-two-bag mesocosm study was carried out between March and July 1998, in Håkøybotn, Tromsø, in order to determine development and mortality rates of the two parallel cohorts of C. finmarchicus. For practical reasons, the cohort from Bergen was incubated 10 days earlier than the Tromsø cohort. Consequently, they were exposed to elevated food conditions as compared to the Tromsø cohort. A high initial mortality among the Bergen cohort could clearly be ascribed, by genetic discrimination, to "contamination" with C. helgolandicus. After this initial mass mortality, the mortality was constantly 0.03–0.04 day−1. In cohorts starting from naupliar stage I, there was no significant difference in development or growth, the median development time (NI–CIV) differing by only 7 days (~6%). The difference in development time can be explained to a large extent (~4 days) by temperature differences. This is substantiated with model simulations using a physiological model developed for C. finmarchicus. There was a time lag in incubation between the two cohorts, resulting in elevated temperature during incubation of the Tromsø cohort. A fraction of both cohorts differentiated sexually at stage CV, with males differentiating before females. Females from both cohorts produced eggs, but specific egg production differed significantly (P>0.001, t-test). This was supported by elevated RNA:DNA ratio in females from the Bergen cohort. Both cohorts demonstrated quite similar development and physiological growth rates and, consequently, are considered to belong to the same genetic population inhabiting the Norwegian Shelf. The study demonstrates that C. finmarchicus is capable of adaptation to changes in environment and, thereby, demonstrates a significant physiological plasticity.

- by Tue Marker
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- Genetics, Marine Biology, Adaptation, Crustacea
- by Satu Huttunen
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- Environmental Pollution, Multidisciplinary, Atmospheric deposition, Nitrogen
- by Matthew Linford
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- Engineering, Thermodynamics, Technology, Principal Component Analysis

Anaerobic digestion is an appropriate technique for the treatment of sludge before final disposal and it is employed worldwide as the oldest and most important process for sludge stabilization. In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic digestion. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization, enhancement of dewatering of the

- by Birgitte Ahring
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- Engineering, Water, Kinetics, Water Purification

The hydrogenation of maleic acid was investigated using a bimetallic RuRe/C catalyst powder in a semi-batch stirred slurry reactor with the main objective of developing a kinetic model that would provide reliable predictions of the... more

- by Tiberiu Leib
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- Mechanical Engineering, Chemical Engineering, Kinetics, Carbon
- by Raimo Ketola
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- Chromatography, Mass Spectrometry, Quality Control, Contamination
- by Brad Bessinger
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- Earth Sciences, Materials Science, Thermodynamics, Chemistry
- by Bayden D Russell
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- Climate Change, Community Ecology, Carbon Dioxide, Biological Sciences
- by Ralph P Cavalieri
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- American Society, Dielectric Properties, Ionic Conductivity, Dielectric Loss
- by Samuel Kenig
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- Composites, Low Temperature, Elevated Temperature
- by TOM RYDING
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- Heat Transfer, X Rays, Crack propagation, Copper

We isolated several thermotolerant Acetobacter species of which MSU10 strain, identified as Acetobacter pasteurianus, could grow well on agar plates at 41°C, tolerate to 1.5% acetic acid or 4% ethanol at 39°C, similarly seen with A. pasteurianus SKU1108 previously isolated. The MSU10 strain showed higher acetic acid productivity in a medium containing 6% ethanol at 37°C than SKU1108 while SKU1108 strain could accumulate more acetic acid in a medium supplemented with 4–5% ethanol at the same temperature. The fermentation ability at 37°C of these thermotolerant strains was superior to that of mesophilic A. pasteurianus IFO3191 strain having weak growth and very delayed acetic acid production at 37°C even at 4% ethanol. Alcohol dehydrogenases (ADHs) were purified from MSU10, SKU1108, and IFO3191 strains, and their properties were compared related to the thermotolerance. ADH of the thermotolerant strains had a little higher optimal temperature and heat stability than that of mesophilic IFO3191. More critically, ADHs from MSU10 and SKU1108 strains exhibited a higher resistance to ethanol and acetic acid than IFO3191 enzyme at elevated temperature. Furthermore, in this study, the ADH genes were cloned, and the amino acid sequences of ADH subunit I, subunit II, and subunit III were compared. The difference in the amino acid residues could be seen, seemingly related to the thermotolerance, between MSU10 or SKU1108 ADH and IFO 3191 ADH.

- by Watchara Kanchanarach
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- Multidisciplinary, Ethanol, Enzyme, Applied Microbiology and Biotechnology
- by Nobumichi Tamura
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- Kinetics, Multidisciplinary, Macromolecular X-Ray Crystallography, X Rays
- by Zhenbao Liu
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- Engineering, Materials Engineering, Mechanical Engineering, Chemical Engineering
- by Gary Adams and +1
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- Materials Engineering, Chemical Engineering, Kinetics, POlymer degradation and stability
- by Brian Shiels
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- Microbiology, Zoology, Stochastic Process, Cell line
- by Darrell Nordstrom
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- Geochemistry, Speciation, Kinetics, Mine Water
- by Heike Schuchmann
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- Mechanical Engineering, Chemical Engineering, Mixing, Homogenization
- by Singh Raman
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- Mechanical Engineering, Stress corrosion cracking, Strain Rate, Crack propagation
- by Donald Palmer
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- Geology, Geochemistry, Vapor Pressure, Ionic Strength
- by A. Pauschitz
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- Mechanical Engineering, Metal Forming, Tribology, Sliding wear
- by Roger Plank
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- Chemical Engineering, Finite Element, High Temperature, Temperature Distribution
- by D. Wolff-boenisch and +1
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- Engineering, Earth Sciences, Thermodynamics, Carbon Dioxide
- by Michael Bozack
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- Behavior change, Temperature Dependence, Room Temperature, Cross Section
- by Akihide Kuwabara
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- Polymorphism, Physical sciences, Normal Modes, Phase transition
- by Fábio Damatta
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- Chemical Engineering, Climate Change, Food, Food Security

Exposure of superalloy surfaces to jet fuel at elevated temperatures leads to the formation of carbonaceous deposits and metal sulfides. The formation of stable oxide layers on alloy surfaces can reduce the activity of the constituent transition metals that catalyze the dehydrogenation of hydrocarbons and the subsequent carbon deposit growth. The metals Ni, Cr, Fe, Mn, Al, Ti and Nb + Ta

- by Semih Eser
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- Thermodynamics, Oxidation of Metals, Transition-Metal Oxides, Thermal Stress

SUMMARY Nitric oxide (NO) is a free radical implicated in numerous cell signaling,physiological and pathophysiological processes of eukaryotic cells. Here, we describe the production of NO as part of the cellular stress response of the symbiotic sea anemone Aiptasia pallida, which hosts dinoflagellates from the genus Symbiodinium. We show that exposure to elevated temperatures induces symbiotic anemones to produce high levels of NO, leading to the collapse of the symbiosis. These results shed light on the poorly understood cellular mechanism through which elevated seawater temperature causes the release of symbiotic algae from symbiotic cnidarians, a detrimental process known as coral (cnidarian) bleaching. The results presented here show that the host cell is a major source of NO during exposure to elevated temperatures and that this constitutes a cytotoxic response leading to bleaching. These results have important evolutionary implications as the observed NO production in these b...

- by santiago Perez
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- Symbiosis, Oxidative Stress, Cell Signaling, Innate immunity
- by Diana Linke
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- Multidisciplinary, Escherichia coli, Enzyme, Molecular cloning