scholarly journals Microbes Thriving in Extreme Environments: How Do They Do It?

2014 ◽  
Vol 2 (4) ◽  
pp. 393-401 ◽  
Author(s):  
Prameela Jha
Keyword(s):  
High Temperature ◽  
Molecular Biology ◽  
Cell Membrane ◽  
Extreme Environments ◽  
External Environment ◽  
Probable Mechanism ◽  
Extreme Conditions ◽  
Thermus Aquaticus ◽  
Taq Polymerase ◽  
Cosmetic Industry

Our knowledge about habitat of microorganisms appears diminutive when we witness amazing flexibility in choice of survival under various conditions. Extremophiles refers to the organisms living and carrying out vital life processes at extreme conditions of temperature, pressure, pH, salt concentration among others and this is why they have attracted attention of researchers worldwide. There is a continuous quest to unreveal the probable mechanism or structural and functional adaptations that make extremophiles survive under other holistic conditions. There occur modifications primarily in cell membrane, DNA, RNA, protein and enzymes in order to render fit microbial cell to its external environment. Thus, extremophiles are robust source of high temperature and alkali stable enzymes. Various enzymes as lipase and protease have found several applications in food and cosmetic industry while Taq polymerase from bacteria Thermus aquaticus has revolutionized entire scene of molecular biology. Present review focuses on extremophiles, their structural and molecular adaptations to overcome unfavorable conditions of environment.DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.10543 Int J Appl Sci Biotechnol, Vol. 2(4): 393-401 

scholarly journals The Versatility of HVOF Burner Rig Testing for Ceramic Matrix Composite Evaluation

2021 ◽  
Vol 5 (8) ◽  
pp. 223
Author(s):  
Gregory N. Morscher ◽  
Ragav P. Panakarajupally ◽  
Leland Hoffman
Keyword(s):  
High Temperature ◽  
High Velocity ◽  
Extreme Environments ◽  
High Stress ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Extreme Conditions ◽  
Matrix Composites ◽  
Test Environment

Effective testing of ceramic matrix composites (CMCs) and CMC/coating systems for high temperature, high stress, high velocity and/or severe oxidation/corrosion environments is a critical need in materials/coatings evaluation for extreme environments of hot section parts in jet engine and hypersonic applications. Most current technology can evaluate two or three of the extreme conditions for a given application; however, incorporating as many of the extreme thermo-mechanical-environmental factors is highly advantageous to understand combinatorial effects. A high velocity oxygen fuel (HVOF) burner rig offers an excellent platform to evaluate many of these extreme conditions. In this work, the following three different thermo-mechanical-environmental test conditions using an HVOF rig on SiC-based CMCs are highlighted: (1) fatigue at temperature for >Mach 1 velocity and high temperature compared to typical stagnant air test environment, (2) high temperature hard particle erosion at temperature for ≤Mach 1 conditions and (3) ~Mach 5 near-hypersonic velocity conditions at very high temperature exposure.

Molecular biology of K+ transport across the plant cell membrane: What do we learn from comparison between plant species?

2014 ◽  
Vol 171 (9) ◽  
pp. 748-769 ◽  
Author(s):  
Anne-Aliénor Véry ◽  
Manuel Nieves-Cordones ◽  
Meriem Daly ◽  
Imran Khan ◽  
Cécile Fizames ◽  
...  
Keyword(s):  
Molecular Biology ◽  
Cell Membrane ◽  
Plant Species ◽  
Plant Cell ◽  
K Transport

Experimental Study on the Drying Performance of the High Temperature Heat Pump Dryer

2012 ◽  
Vol 550-553 ◽  
pp. 3219-3223
Author(s):  
Xing Wang Zhu ◽  
Chun Xia Hu ◽  
Zhi Min Guo ◽  
Yu Gui Su
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
External Environment ◽  
Stable Operation ◽  
Obvious Effect ◽  
Electromagnetic Valve ◽  
Exhaust Temperature ◽  
Temperature Heat ◽  
High Temperature Heat Pump

In this paper，a high temperature heat-pump dryer and a corresponding semi-enclosed test drying room for using the dryer are built up respectively. While the average dry bulb of the external environment is 25°C and the relative humidity is 55%, the performance of the dryer is obtained when the dryer is running continuously for five hours. The results show that: the electromagnetic valve-capillary institution has an obvious effect on the lower the dryer exhaust temperature. It makes the suction temperature of compressor dropped 10 °C~15 °C, which can reduce the exhaust temperature and prevent compressor’s overheating. When the exhaust temperature keep at 100~110 °C, it can not only guarantee the temperature of wind coming from the dryer is high, but also can make sure the drying system’s long-term stable operation.

High-Entropy Ultra-High-Temperature Borides and Carbides: A New Class of Materials for Extreme Environments

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Lun Feng ◽  
William G. Fahrenholtz ◽  
Donald W. Brenner
Keyword(s):  
High Temperature ◽  
Extreme Environments ◽  
Experimental Studies ◽  
Heat Fluxes ◽  
Annual Review ◽  
Publication Date ◽  
Structure Property ◽  
High Entropy ◽  
Ultra High Temperature Ceramics ◽  
Ultra High Temperature

Herein, we critically evaluate computational and experimental studies in the emerging field of high-entropy ultra-high-temperature ceramics. High-entropy ultra-high-temperature ceramics are candidates for use in extreme environments that include temperatures over 2,000°C, heat fluxes of hundreds of watts per square centimeter, or irradiation from neutrons with energies of several megaelectron volts. Computational studies have been used to predict the ability to synthesize stable high-entropy materials as well as the resulting properties but face challenges such asthe number and complexity of unique bonding environments that are possible for these compositionally complex compounds. Experimental studies have synthesized and densified a large number of different high-entropy borides and carbides, but no systematic studies of composition-structure-property relationships have been completed. Overall, this emerging field presents a number of exciting research challenges and numerous opportunities for future studies. Expected final online publication date for the Annual Review of Materials Science, Volume 51 is July 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Development of Creep-Resistant, Alumina-Forming Ferrous Alloys for High-Temperature Structural Use

2018 ◽  
Author(s):  
Y. Yamamoto ◽  
M. P. Brady ◽  
G. Muralidharan ◽  
B. A. Pint ◽  
P. J. Maziasz ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Extreme Environments ◽  
Alloy Design ◽  
Austenitic Steels ◽  
Strength Development ◽  
Second Phase ◽  
Ferrous Alloys ◽  
Steel Alloys ◽  
Structural Applications

This paper overviews recent advances in developing novel alloy design concepts of creep-resistant, alumina-forming Fe-base alloys, including both ferritic and austenitic steels, for high-temperature structural applications in fossil-fired power generation systems. Protective, external alumina-scales offer improved oxidation resistance compared to chromia-scales in steam-containing environments at elevated temperatures. Alloy design utilizes computational thermodynamic tools with compositional guidelines based on experimental results accumulated in the last decade, along with design and control of the second-phase precipitates to maximize high-temperature strengths. The alloys developed to date, including ferritic (Fe-Cr-Al-Nb-W base) and austenitic (Fe-Cr-Ni-Al-Nb base) alloys, successfully incorporated the balanced properties of steam/water vapor-oxidation and/or ash-corrosion resistance and improved creep strength. Development of cast alumina-forming austenitic (AFA) stainless steel alloys is also in progress with successful improvement of higher temperature capability targeting up to ∼1100°C. Current alloy design approach and developmental efforts with guidance of computational tools were found to be beneficial for further development of the new heat resistant steel alloys for various extreme environments.

scholarly journals Cell Membrane Stability as a Measure of Heat Tolerance in Hexaploid and Tetraploid Wheat

2020 ◽  
pp. 16-22
Author(s):  
Syed Bilal Hussain ◽  
Ali Bakhsh ◽  
Muhammad Zubair
Keyword(s):  
High Temperature ◽  
Cell Membrane ◽  
Temperature Stress ◽  
Heat Tolerance ◽  
Tetraploid Wheat ◽  
High Temperature Stress ◽  
Cell Membrane Stability ◽  
Leaf Stage ◽  
Heat Tolerant ◽  
Morphological Differences

A comparison was made of the physiological and morphological differences between Inqlab-91 (hexaploid) and Langdon (tetralpoid) wheat genotypes in response to high temperature stress applied at third leaf stage of growth. Electrolytes leakage technique was used to detect differences in the heat sensitivities of leaves of Inqlab-91 and Langdon. This method showed that at both 35 or 40°C Inqlab-91 was more heat tolerant than Langdon.

Unprecedented metallic BiS phase from the binary Bi–S family revisited under extreme conditions of high pressure and high temperature

2020 ◽  
Vol 318 ◽  
pp. 113984
Author(s):  
Yanmei Ma ◽  
Ruihong Li ◽  
Yingying Wang ◽  
Fangfei Li ◽  
Guangtao Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Extreme Conditions

scholarly journals Design, Fabrication, and Characterization of New Materials Based on Zirconia Doped with Mixed Rare Earth Oxides: Review and First Experimental Results

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 746 ◽  
Author(s):  
Adrian Mihail Motoc ◽  
Sorina Valsan ◽  
Anca Elena Slobozeanu ◽  
Mircea Corban ◽  
Daniele Valerini ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Extreme Environments ◽  
Chemical Properties ◽  
Electronic Configuration ◽  
Electron Beam Evaporation ◽  
Rare Earth Oxides ◽  
Added Value ◽  
High Price ◽  
Preliminary Results

Monazite is one of the most valuable natural resources for rare earth oxides (REOs) used as dopants with high added value in ceramic materials for extreme environments applications. The complexity of the separation process in individual REOs, due to their similar electronic configuration and physical–chemical properties, is reflected in products with high price and high environmental footprint. During last years, there was an increasing interest for using different mixtures of REOs as dopants for high temperature ceramics, in particular for ZrO2-based thermal barrier coatings (TBCs) used in aeronautics and energy co-generation. The use of mixed REOs may increase the working temperature of the TBCs due to the formation of tetragonal and cubic solid solutions with higher melting temperatures, avoiding grain size coarsening due to interface segregation, enhancing its ionic conductivity and sinterability. The thermal stability of the coatings may be further improved by using rare earth zirconates with perovskite or pyrochlore structures having no phase transitions before melting. Within this research framework, firstly we present a review analysis about results reported in the literature so far about the use of ZrO2 ceramics doped with mixed REOs for high temperature applications. Then, preliminary results about TBCs fabricated by electron beam evaporation starting from mixed REOs simulating the real composition as occurring in monazite source minerals are reported. This novel recipe for ZrO2-based TBCs, if optimized, may lead to better materials with lower costs and lower environmental impact, as a result of the elimination of REOs extraction and separation in individual lanthanides. Preliminary results on the compositional, microstructure, morphological, and thermal properties of the tested materials are reported.

Cantilever creep method for testing ceramic composites and a case study for chemically bonded phosphate ceramic composites reinforced with glass, carbon and basalt fibers, including both experiments and simulations

2020 ◽  
Vol 54 (20) ◽  
pp. 2663-2676
Author(s):  
Henry A Colorado ◽  
Elkin I Gutiérrez-Velásquez ◽  
Clem Hiel
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
Extreme Environments ◽  
Ceramic Composites ◽  
High Temperature Creep ◽  
Creep Tests ◽  
Element Analysis ◽  
Temperature Creep ◽  
Glass Carbon ◽  
Electron Microscopy Analysis

This paper presented the cantilever beam experiments and the method for creep in chemically bonded ceramics reinforced with glass, carbon, and basalt unidirectional fibers. The ceramic composite samples were fabricated by mixing wollastonite powder and phosphoric acid, through the resonant acoustic mixing technique. The reinforced fibers were added via pultrusion process. The manufactured materials were exposed to high temperature creep tests at 600, 800 and 1000℃, with an annealing time of 1 h, all in air environment. Some examples of real large-scale structures made manually by a company were also included. In order to understand the microstructure, X-ray diffraction and scanning electron microscopy analysis were included. The presented method is simple and can be used in any inorganic ceramic slurry types, such as geopolymers, phosphate cements, clay-based materials, or Portland cement composites. The sample response in high temperature creep experiments was analyzed with a new but very simple technique, and modeled using finite element analysis over all compositions. Results revealed that fibers have a significant effect on the composite creep when compared to the ceramic without reinforcement, and particularly carbon fibers showed a quite interested effect in reducing the creep effects. Results show the limit of the materials under conditions typically found in fires and other extreme environments.

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