Relevant bibliographies by topics / High temperature shock

Academic literature on the topic 'High temperature shock'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "High temperature shock"

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Popa, Iustin Alexandru, Andreea Elena Rosu, Gabriel Neacsu, Daniel Constantin Anghel, Vasile Rizea, Mihai Branzei, Catalin Marian Ducu, Maria Magdalena Dicu, and Marioara Abrudeanu. "The Influence of the High Temperatures Thermal Shocks on the Microstructure and Harness of Zircaloy-4 alloy." Revista de Chimie 69, no. 7 (August 15, 2018): 1655–60. http://dx.doi.org/10.37358/rc.18.7.6389.

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This study aims at determining the influence of thermal shocks at high temperatures, over the allotropic temperature, on the microstructure, composition and hardness of the Zy-4 sheath. The thermal shocks have been applied at the temperatures between 900 and 1600�C, in the air, lasting 30 and 60 s, through rapid heating in the solar furnace. The treated samples were microstructurally analyzed on the surface and in section by scanning electron microscopy and EDS, thickness measurement of the formed layers, the oxygen and hardness profile determination in section relative to the treated surface. At the microstructural level, the researches have revealed the evolution of the morphology of the oxide layers formed under high temperature thermal shock conditions and the evolution of the microstructure of the metallic mass as the temperature and shock duration increase, correlating this evolution with the oxygen diffusion process and with the evolution of the microhardness. Researches have provided information on the Zy-4 alloy behaviour under accidental conditions.
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Wang, R. Z., S. G. Ai, W. G. Li, J. Zheng, and C. Z. Zhang. "Temperature and Microstructures Dependent Thermal Shock Resistance Models for Ultra-High-Temperature Ceramics Considering Effect of Residual Stress." Journal of Mechanics 29, no. 4 (August 8, 2013): 695–702. http://dx.doi.org/10.1017/jmech.2013.41.

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ABSTRACTBased on the researches on the temperature and microstructures dependent fracture strength and temperature dependent thermal shock resistance, the new thermal shock resistance models for ultra-high-temperature ceramics were proposed. The effect of density on the fracture strength of material was investigated. A damage term was introduced to reveal the effects of uncertain factors on fracture strength. The roles of residual stress and microstructure sizes at different initial thermal shock temperatures in the thermal shock resistance were studied using the models. The study showed that the models can reveal the relationships among the residual stress, microstructure sizes and the temperature dependent thermal shock resistance well. The better thermal shock resistance is found for ultra-high-temperature ceramics having small SiC grains and relatively large micro-cracks around SiC grains. Large enhancement in thermal shock resistance can be achieved through our studies.
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Li, Wei Guo, and Dai Ning Fang. "Thermal Shock Resistance of Ultra-High Temperature Ceramics." Key Engineering Materials 368-372 (February 2008): 1782–84. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1782.

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Thermal shock resistance of Ultra-High Temperature Ceramics is one of the most important parameters in UHTCs characterization since it determines their performance in many applications. In order to reflect practical cases, the temperature-dependent thermal shock resistance parameter of UHTCS was measured since the material parameters of UHTCs are very sensitive to the changes of temperature. The influence of some important thermal environment parameters and the size of the material on the thermal shock resistance and critical temperature difference of rupture of UHTCs at different stages in the thermal-shock process were investigated. The results show that thermal shock behaviour of the UHTCs is strongly affected by the size of the material and the thermal environments parameters, such as the surface heat transfer coefficient, heat transfer condition and initial temperature of the thermal shock.
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Moeini, S. Ali, Hannes Greve, and F. Patrick McCluskey. "Strength and Reliability of High Temperature Transient Liquid Phase Sintered Joints." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, HITEC (January 1, 2014): 000355–63. http://dx.doi.org/10.4071/hitec-tha25.

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Low-temperature transient liquid phase sintering (LT-TLPS) can be used to form high-temperature joints between metallic interfaces at low process temperatures. In this paper, we will describe the processing and shear strength, along with the shock fatigue resistance of sintered joints made by this process. Joints made from different ratios of Ni and Cu high melting temperature constituents paired with Sn-based low melting temperature constituents have been evaluated. For the shear studies, the softening behavior of test samples joined by Ni-Sn3.5Ag and (Ni,Cu)-Sn3.5Ag sinter pastes have been assessed using a fixture designed for high temperature shear testing up to 600°C. The reliability of sinter paste joints in drop-shock environments will be discussed. It is shown that joints formed from these sinter pastes possess improved drop-shock reliability compared to Sn3.5Ag solder joints and melting temperatures considerably higher than those of conventional high temperature solders (e.g. Pb5.0Sn2.5Ag).
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Souza, Gustavo M., Victor J. M. Cardoso, and Antonio N. Gonçalves. "Proline content and protein patterns in Eucalyptus grandis shoots submitted to high and low temperature shocks." Brazilian Archives of Biology and Technology 47, no. 3 (July 2004): 355–62. http://dx.doi.org/10.1590/s1516-89132004000300004.

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Proline content and protein patterns changes in response to temperature shocks of both acclimated and non acclimated E. grandis shoots cultivated in vitro were investigated. Analysis of soluble proteins through SDS-PAGE and proline were carried out after 12h at 12ºC (cold acclimation) or 33ºC (heat acclimation), and immediately after temperature shocks at 41ºC and 0ºC. Analyses were also performed 24h after the temperature shocks (recovery period). Temperature treatment at 0ºC did not change soluble protein patterns both in acclimatized and non acclimatized plants, whereas cold temperature induced high proline levels, which kept relatively high after recovery period. Three novel, probably HSPs, proteins (90.5, 75 and 39 kDa) were observed in both acclimated and non acclimated plants submitted to high temperatures. Plants exposed at 41ºC were able to recover from heat shocks after 24h, whereas they did not recover completely from cold shocks. The effect of the acclimation period on the recovering (homeostasis) varied depending on the parameter evaluated, and type and duration of the temperature shock.
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Bossi, Simone, Tom A. Hall, Mohammed Mahdieh, Dimitri Batani, Michel Koenig, Jothy Krishnan, Alessandra Benuzzi, Jean Michel Boudenne, and Thorsten Lower. "Determination of the color temperature in laser-produced shocks." Laser and Particle Beams 15, no. 4 (December 1997): 485–93. http://dx.doi.org/10.1017/s0263034600011071.

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Experimental results on the determination of the color temperature in shock waves produced with lasers are presented. The method is based on imaging the target rear side in two different spectral windows and on using phased zone plates to produce high-quality shocks. The shock velocity is also measured, allowing, with the use of the equation of state, the real shock temperature to be deduced and compared with the measured color temperature.
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Sealy, Cordelia. "Flexible ceramic fibers resist high temperature shock." Nano Today 44 (June 2022): 101491. http://dx.doi.org/10.1016/j.nantod.2022.101491.

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Sealy, Cordelia. "Flexible ceramic fibers resist high temperature shock." Nano Today 44 (June 2022): 101491. http://dx.doi.org/10.1016/j.nantod.2022.101491.

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Weir, S. T., W. J. Nellis, C. L. Seaman, E. A. Early, M. B. Maple, Matthew J. Kramer, J. Z. Liu, and R. N. Shelton. "Shock-Wave Processing of High-Temperature Superconductors." Materials Science Forum 137-139 (August 1993): 355–76. http://dx.doi.org/10.4028/www.scientific.net/msf.137-139.355.

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Shen, Yan-Jun, Xin Hou, Jiang-Qiang Yuan, and Chun-Hu Zhao. "Experimental Study on Temperature Change and Crack Expansion of High Temperature Granite under Different Cooling Shock Treatments." Energies 12, no. 11 (May 31, 2019): 2097. http://dx.doi.org/10.3390/en12112097.

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It is valuable to observe the influence of different cooling methods on the exploitation of geothermal energy and breaking hard rocks in deep geo-engineering. In this work, the effects of different cooling shock treatments on high temperature granite are discussed. First, perforated 100-mm-side cubic biotite adamellite samples were heated to four targeted temperatures (150 °C, 350 °C, 550 °C, and 750 °C). Then, anti-freeze solutions were compounded to produce the different cooling shock effects (20 °C, 0 °C, and −30 °C) by adjusting the calcium chloride solution concentration, and these anti-freeze solutions were injected rapidly into the holes to reflect the rapid cooling shock of high-temperature granite. Finally, the temperature variations and crack expansions of high-temperature granite under different cooling shock treatments were analyzed and the cooling shock cracking mechanism is discussed briefly. The main results can be summarized as: (1) The high temperature granite exposed to the cooling shock exhibited a "rapid cooling + rapid heating" change during the first 5 min. Due to the cooling shock, the total temperature was significantly lower than the natural cooling until 120 min later. (2) Below 350 °C, the macrocracking effect was not significant, and the sample reflected a certain range of uniform microcracks around the injection hole, while the macrocracks tended to be obvious above 550 °C. Moreover, as the refrigerant temperature decreased, the local distribution characteristics of the macrocracking became more obvious. (3) Based on the analysis of the dynamic heat balance, the undulation and width of the cracks around the heat balance zone were stable, but the numbers and widths of cracks near the hole wall and the side of the sample were visibly increased. This study extends our understanding of the influence of cooling shock on granite cracking.
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Dissertations / Theses on the topic "High temperature shock"

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Kapper, Michael Gino. "A High-Order Transport Scheme for Collisional-Radiative and Nonequilibrium Plasma." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245427632.

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McDonald, Heather Brown. "The effect of sulfide inhibition and organic shock loading on anaerobic biofilm reactors treating a low-temperature, high-sulfate wastewater." Diss., University of Iowa, 2007. http://ir.uiowa.edu/etd/129.

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北村, 圭一, Keiichi KITAMURA, 啓伺 小澤, Hiroshi OZAWA, 勝祥 花井, Katsuhisa HANAI, 浩一 森, Koichi MORI, 佳朗 中村, and Yoshiaki NAKAMURA. "極超音速TSTOにおける衝撃波干渉・境界層剥離を伴う流れ場の解析." 日本航空宇宙学会, 2008. http://hdl.handle.net/2237/13872.

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Kanjer, Armand. "De l'efficacité des procédés SMAT et de choc laser dans l'amélioration de la tenue à l'oxydation haute température d'alliages de titane." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK003/document.

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Cette thèse vise à déterminer l’influence de deux traitements mécaniques, le grenaillage SMAT effectué avec plusieurs types de billes (en WC, en alumine et en verre) et le choc laser, sur la résistance à l’oxydation haute température de deux alliages de titane : un alliage alpha commercialement « pur » (Grade 1) et un alliage aéronautique béta métastable (TIMETAL-21S).Une fois traitées, les pièces sont oxydées avec différentes conditions : de durée (entre 5 heures pour étudier les premier instants de l’oxydation et 3000h pour se rapprocher d’un essai type en aéronautique), de température (600°C à 700°C) et d’atmosphère (air sec et oxygène).Les pièces sont analysées avant et après oxydation à l’aide de plusieurs techniques d’analyses : mécaniques (dureté, mesures de contraintes), chimiques (DRX, microsonde nucléaire, …) ou structurales (EBSD, texture).Les résultats obtenus montrent que les traitements perturbent fortement les pièces avant leur exposition à haute température d’un point de vue morphologique, structural, mécanique et chimique. Ces traitements mécaniques amènent une réduction de l’oxydation des pièces étudiées. Il semble qu’ils modifient la vitesse de diffusion des espèces (azote, oxygène, aluminium, molybdène) mais aussi la microstructure (recristallisation, morphologie de grain ou texturation) au cours de la mise en température. L’azote joue un rôle essentiel dans les phénomènes observés.Néanmoins, la détermination des conséquences de ces traitements sur la résistance à l’oxydation reste encore complexe de par les observations de ce travail, qui révèlent une contribution simultanée de plusieurs facteurs : chimiques, mécaniques et structuraux
The aim of this thesis is to determine the influence of two mechanical surface treatments, the shot- peening performed with several type of balls (WC, alumina and glass) and the laser shock peening, on the high temperature oxidation resistance of two titanium alloys : alpha alloy with commercially purity (Grade 1) and aeronautical beta metastable alloy (TIMETAL-21S).After different treatments, the pieces are oxidized with different conditions: of time (between 5 hours to study the firsts times of oxidation and 3000 hours to compare with a classical aeronautical test), of temperature (600°C to 700°C) and atmosphere (dry air or oxygen).The pieces are analyzed before and after oxidation exposure with several mechanical (micro-hardness, strain measurements), chemicals (XRD, nuclear microprobe) and structural (EBSD, texture) techniques. The results show a large surface perturbation before the high temperature exposure in term of morphological, mechanical, structural and chemical point of view.This mechanical treatments lead up to an oxidation rate reduction for all the different titanium alloys. This treatments modified the diffusion rate of several elements (nitrogen, oxygen, molybdenum or aluminum) but also the microstructure (recrystallization, grain morphology or texturing) during high temperature exposure. Nitrogen element plays an important role in the observed phenomena.However, the determination of consequences after mechanical treatment on the titanium oxidation resistance is again difficult with the observations noted in this work. Actually, there is a simultaneous contributions of several factors: chemical, mechanical and structural
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Fahr, Payam. "Response of filled corrugated sandwich structures to shock loading at high temperatures." Thesis, University of Rhode Island, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1555644.

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The dynamic response of filled corrugated steel sandwich panels was investigated under combined extremes of blast loading and high temperature heating. The objective of this project was to study blast mitigation and the thermo-mechanical response of panels using a polymer based syntactic foam and mortar as a filler material. These materials were selected due to their thermal resistivity. In this study, silicone resin (with an operating temperature range between -53°C to 232°C) and two types of glass bubbles were selected as materials to develop a heat resistive syntactic foam. The mechanical properties of the foam were investigated, in ambient temperatures, before and after high-temperature heat treatment (of 500°C), by quasi-static compression experiments. It was observed that plateau stress increases after introduction of glass bubbles in silicone, enhancing the energy absorption properties for both specimens with and without heat treatment. To produce repeatable blast loading, a shock tube was utilized. Pressure history was recorded using pressure transducers located in the shock tube muzzle. High speed photo-optical methods utilizing Digital Image Correlation (DIC) coupled with optical band-pass filters and high-intensity light source, were utilized to obtain the real-time deformation at high temperature while a third camera captured side-view deformation images. The shock pressure profiles and DIC analysis were used to obtain the impulse imparted to the specimen, transient deflection, in plane strain and out-of-plane velocity of the back face sheet. Shock tube experiments were performed to investigate the blast response of corrugated steel sandwich panels filled with a silicone based syntactic foam filler at room and high temperature. It was observed that using the syntactic foam as a filler material, decreased the front face and back face deflections by 42% and 27%, respectively, compared to an empty panel. The highest impulse was imparted on the specimen at room temperature and subsequently lower impulses with increasing temperature. Due to increasing ductility in steel with high temperature, the specimens demonstrated an increase in back face deflection, in-plane strain and out-of-plane velocity with increasing temperatures with weld failure being the primary form of core damage. High temperature blast experiments were also performed on mortar filled corrugated steel sandwich panels. Mortar is a common building material that can withstand extreme temperatures. It was observed cement based mortars are thermally resilient enough to be used as a filler material for high temperature applications. The highest impulse was imparted on the specimen at room temperature and subsequently lower impulses with increasing temperature. A temperature difference of at least 300ºC was observed across the thickness of the specimen for all heating conditions. Due to increasing ductility in steel with high temperature, the specimens demonstrated an increase in back face deflection, in-plane strain and out-of-plane velocity with increasing temperatures with weld failure being the primary form of core damage.

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Hall, Joel. "AN Optimized Kinetics Model for OH Chemiluminescence at High Temperatures and Atmospheric Pressures." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2086.

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Chemiluminescence from the OH(A-X) transition near 307 nm is a commonly used diagnostic in combustion applications such as flame chemistry, shock-tube experiments, and reacting-flow visualization. Measurements of the chemiluminescent intensity provide a simple, cost-effective, non-intrusive look at the combustion environment. The presence of the ultra-violet emission is often used as an indicator of the flame zone in practical combustion systems, and its intensity may be correlated to the temperature distribution or other parameters of interest. While absolute measurements of the ground-state OH(X) concentrations are well-defined, there is no elementary relation between emission from the electronically excited state (OH*) and its absolute concentration. Thus, to enable quantitative emission measurements, a kinetics model has been assembled and optimized to predict OH* formation and quenching at combustion conditions. Shock-tube experiments were conducted in mixtures of H2/O2/Ar, CH4/O2/Ar and CH4/H2/O2/Ar with high levels of argon dilution (> 98%). Elementary reactions to model OH*, along with initial estimates of their rate coefficients, were taken from the literature. The important formation steps follow. CH + O2 = OH* + CO (R0) H + O + M = OH* + M (R1) H + OH + OH = OH* + H2O (R2) Sensitivity analyses were performed to design experiments at conditions most sensitive to the formation reactions. A fitting routine was developed to express the key rate parameters as a function of a single rate, k1 at the reference temperature (1490 K). With all rates so expressed, H2/CH4 mixtures were designed to uniquely determine the value of k1 at the reference temperature, from which the remaining rate parameters were calculated. Quenching rates were fixed at their literature values. Comparisons to predictions of previously available models show marked improvement relative to the new shock-tube data. An approach for using this work in the calibration of further measurements is outlined taking examples from a recent ethane oxidation study. The new model qualitatively matches the experimental data over the range of conditions studied and provides quantitative results applicable to real combustion environments, containing higher-order hydrocarbon fuels and lower levels of dilution in air.
M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
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Kalitan, Danielle Marie. "A Study of Syngas Oxidation at High Pressures and Low Temperatures." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2422.

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Ignition and oxidation characteristics of CO/H2, H2/O2 and CO/H2/CH4/CO2/Ar fuel blends in air were studied using both experimental and computer simulation methods. Shock-tube experiments were conducted behind reflected shock waves at intermediate temperatures (825 < T < 1400 K) for a wide range of pressures (1 < P < 45 atm). Results of this study provide the first undiluted fuel-air ignition delay time experiments to cover such a wide range of syngas mixture compositions over the stated temperature range. Emission in the form of chemiluminescence from the hydroxyl radical (OH*) transition near 307 nm and the pressure behind the reflected shock wave were used to monitor reaction progress from which ignition delay times were determined. In addition to the experimental analysis, chemical kinetics calculations were completed to compare several chemical kinetics mechanisms to the new experimental results. Overall, the models were in good agreement with the shock-tube data, especially at higher temperatures and lower pressures, yet there were some differences between the models at higher pressures and the lowest temperatures, in some cases by as much as a factor of five. In order to discern additional information from the chemical kinetics mechanisms regarding their response to a wide range of experimental conditions, ignition delay time and reaction rate sensitivity analyses were completed at higher and lower temperatures and higher and lower pressures. These two sensitivity analyses allow for the identification of the key reactions responsible for ignition. The results of the sensitivity analysis indicate that the ignition-enhancing reaction H + O2 = O + OH and hydrogen oxidation kinetics in general were most important regardless of mixture composition, temperature or pressure. However, lower-temperature, higher-pressure ignition delay time results indicate additional influence from HO2- and CO- containing reactions, particularly the well-known H + O + M = HO2 + M reaction and also the CO + O + M = CO2 + M and CO + HO2 = CO2 + OH reactions. Differences in the rates of the CO-related reactions are shown to be the cause of some of the discrepancies amongst the various models at elevated pressures. However, the deviation between the models and the experimental data at the lowest temperatures could not be entirely explained by discrepancies in the current rates of the reactions contained within the mechanisms. Additional calculations were therefore performed to gain further understanding regarding the opposing ignition behavior for calculated and measured ignition delay time results. Impurities, friction induced ionization, static charge accumulation, boundary layer effects, wall reaction effects, and revised chemical kinetics were all considered to be possible mechanisms for the model and measured data disparity. For the case of wall-reaction effects, additional shock-tube experiments were conducted. For the remaining effects listed above, only detailed calculations were conducted. Results from this preliminary anomaly study are at this time inconclusive, but likely avenues for future study were identified. Additional kinetics calculations showed that the large difference between the experimental data and the chemical kinetics models predictions at low temperatures can be explained by at least one missing reaction relevant to low-temperature and high-pressure experimental conditions involving the formation of H2O2, although further study beyond the scope of this thesis is required to prove this hypothesis both theoretically and experimentally.
Ph.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering PhD
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Bräuer, Jörg. "Erarbeitung eines Raumtemperatur-Waferbondverfahrens basierend auf integrierten und reaktiven nanoskaligen Multilagensystemen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-132820.

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Die vorliegende Arbeit beschreibt einen neuartigen Fügeprozess, das sogenannte reaktive Fügen bzw. Bonden. Hierbei werden sich selbsterhaltene exotherme Reaktionen in nanoskaligen Schichtsystemen als lokale Wärmequelle für das Fügen unterschiedlichster Substrate der Mikrosystemtechnik verwendet. Das Bonden mit den reaktiven Systemen unterscheidet sich von herkömmlichen Verfahren der Aufbau- und Verbindungstechnik primär dadurch, dass durch die rasche Reaktionsausbreitung bei gleichzeitig kleinem Reaktionsvolumen die Fügetemperaturen unmittelbar auf die Fügefläche beschränkt bleiben. Entgegen den herkömmlichen Fügeverfahren mit Wärmeeintrag im Volumen, schont das neue Verfahren empfindliche Bauteile und Materialien mit unterschiedlichsten thermischen Ausdehnungskoeffizienten lassen sich besser verbinden. In der vorliegenden Arbeit werden die Grundlagen zur Dimensionierung, Prozessierung und Integration der gesputterten reaktiven Materialsysteme beschrieben. Diese Systeme werden verwendet, um heterogene Materialien mit unterschiedlichen Durchmessern innerhalb kürzester Zeit auf Wafer-Ebene und bei Raumtemperatur zu bonden. Die so erzeugten Verbindungen werden hinsichtlich der Mikrostruktur, der Zuverlässigkeit sowie der Dichtheit untersucht und bewertet. Zusätzlich wird die Temperaturverteilung in der Fügezone während des Fügeprozesses mit numerischen Methoden vorhergesagt.
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Jayaram, V. "Experimental Investigations Of Surface Interactions Of Shock Heated Gases On High Temperature Materials Using High Enthalpy Shock Tubes." Thesis, 2007. http://hdl.handle.net/2005/495.

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The re-entry space vehicles encounter high temperatures when they enter the earth atmosphere and the high temperature air in the shock layer around the body undergoes partial dissociation. Also, the gas molecules injected into the shock layer from the ablative thermal protection system (TPS) undergo pyrolysis which helps in reducing the net heat flux to the vehicle surface. The chemical species due to the pyrolysis add complexity to the stagnation flow chemistry (52 chemical reactions) models which include species like NOx, CO and hydrocarbons (HCs). Although the ablative TPS is responsible for the safety of re-entry space vehicle, the induced chemical species result in variety of adverse effects on environment such as global warming, acid rain, green house effect etc. The well known three-way-catalyst (TWC) involves simultaneous removal of all the three gases (i.e, NOx, CO, Hydrocarbons) present in the shock layer. Interaction of such three-way-catalyst on the heat shield materials or on the wall of the re-entry space vehicle is to reduce the heat flux and to remove the gases in the shock layer, which is an important issue. For the re-entry vehicle the maximum aerodynamic heating occurs at an altitude ranging about 68 to 45 km during which the vehicle is surrounded by high temperature dissociated air. Then the simplest real gas model of air is the five species model which is based on N2, O2, O, NO and N. This five species model assumes no ionization and no pyrolysis gases are emitted from the heat shield materials. The experimental research work presented in this thesis is directed towards the understanding of catalytic and non-catalytic surface reactions on high temperature materials in presence of strong shock heated test gas. We have also explored the possibility of using shock tube as a high enthalpy device for synthesis of new materials. In the first Chapter, we have presented an overview of re-entry space vehicles, thermal protection system (TPS) and importance of real gas effects in the shock layer. Literature survey on TPS, ablative materials and aerothermochemistry at the stagnation point of reentry capsule, in addition to catalytic and non-catalytic surface reactions between the wall and dissociated air in the shock layer are presented. In Chapters 2 and 3, we present the experimental techniques used to study surface reactions on high temperature materials. A brief description of HST2 shock tunnel is presented and this shock tunnel is capable of generating flow stagnation enthalpies ranging from 0.7 to 5 MJ/kg and has an effective test time of ~ 800 µs. High speed data acquisition system (National Instruments and Yokogawa) used to acquire data from shock tube experiments. The experimental methods like X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Raman and FTIR spectroscopy have been used to characterize the shock-exposed materials. Preliminary research work on surface nitridation of pure metals with shock heated nitrogen gas is discussed in Chapter 2. Surface nitridation of pure Al thin film with shock heated N2 is presented in Chapter 3. An XPS study shows that Al 2p peak at 74.2 eV is due to the formation AlN on the surface of Al thin film due to heterogeneous non-catalytic surface reaction. SEM results show changes in surface morphology of AlN film due to shock wave interaction. Thickness of AlN film on the surface increased with the increase in temperature of the shock heated nitrogen gas. However, HST2 did not produce sufficient temperature and pressure to carry out real conditions of re-entry. Therefore design and development of a new high enthalpy shock tunnel was taken up. In Chapter 4, we present the details of design and fabrication of free piston driven shock tunnel (FPST) to generate high enthalpy test gas along with the development of platinum (Pt) and thermocouple sensors for heat transfer measurement. A free piston driven shock tunnel consists of a high pressure gas reservoir, compression tube, shock tube, nozzle, test section and dump tank connected to a vacuum pumping system. Compression tube has a provision to fill helium gas and four ports, used to mount optical sensors to monitor the piston speed and pressure transducer to record pressure at the end of the compression tube when the piston is launched. Piston can attain a maximum speed of 150 m/s and compress the gas inside the compression tube. The compressed gas bursts the metal diaphragm and generates strong shock wave in the shock tube. This tunnel produces total pressure of about 300 bar and temperature of about 6000 K and is capable of producing a stagnation enthalpy up to 45 MJ/kg. The calibration of nozzle was carried out by measuring the pitot tube pressure in the dump tank. Experimentally recorded P5 pressure at end of the shock tube is compared with Numerical codes. Calibrated pressure P5 values are used to calculate the temperature T5 of the reflected shock waves. This high pressure and high temperature shock heated test gas interacts with the surface of the high temperature test materials. For the measurement of heat transfer rate, platinum thin film sensors are developed using DC magnetron sputtering unit. Hard protective layer of aluminum nitride (AlN) on Pt thin film was deposited by reactive DC magnetron sputtering to measure heat transfer rate in high enthalpy tunnel. After the calibration studies, FPST is used to study the heat transfer rate and to investigate catalytic/non-catalytic surface reaction on high temperature materials. In Chapter 5, an experimental investigation of non-catalytic surface reactions on pure carbon material is presented. The pure carbon C60 films and conducting carbon films are deposited on Macor substrate in the laboratory to perform shock tube experiments. These carbon films were exposed to strong shock heated N2 gas in the shock tube portion of the FPST tunnel. The typical shock Mach number obtained is about 7 with the corresponding pressure and temperature jumps of about 110 bar and 5400 K after reflection at end of the shock tube. Shock exposed carbon films were examined by different experimental techniques. XPS spectra of C(1s) peak at 285.8 eV is attributed to sp2 (C=N) and 287.3 eV peak is attributed to sp3 (C-N) bond in CNx due to carbon nitride. Similarly, N(1s) core level peak at 398.6 eV and 400.1 eV observed are attributed to sp3-C-N and sp2-C=N of carbon nitride, respectively. SEM study shows the formation of carbon nitride crystals. Carbon C60 had melted and undergone non-catalytic surface reaction with N2 while forming carbon nitride. Similar observations were made with conducting carbon films but the crystals were spherical in shape. Micro Raman and FTIR study gave further evidence on the formation of carbon nitride film. This experimental investigation confirms the formation of carbon nitride in presence of shock-heated nitrogen gas by non-catalytic surface reaction. In Chapters 6 and 7, we present a novel method to understand fully catalytic surface reactions after exposure to shock heated N2, O2 and Ar test gas with high temperature materials. We have employed nano ZrO2 and nano Ce0.5Zr0.5O2 ceramic high temperature materials to investigate surface catalytic reactions in presence of shock heated test gases. These nano crystalline oxides are synthesized by a single step solution combustion method. Catalytic reaction was confirmed for both powder and film samples of ZrO2. As per the theoretical model, it is known that the catalytic recombination reaction produces maximum heating on the surface of re-entry space vehicles. This was demonstrated in this experiment when a metastable cubic ZrO2 changed to stable monoclinic ZrO2 phase after exposure to shock waves. The change of crystal structure was seen using XRD studies and needle type monoclinic crystal growth with aspect ratio (L/D) more than 15 was confirmed by SEM studies. XPS of Zr(3d) core level spectra show no change in binding energy before and after exposure to shock waves, confirming that ZrO2 does not change its chemical nature, which is the signature of catalytic surface reaction. When a shock heated argon gas interacted with Ce0.5Zr0.5O2 compound, there was a change in colour from pale yellow to black due to reduction of the compound, which is the effect of heat transfer from the shock wave to the compound in presence of argon gas. The reduction reaction shows the release of oxygen from the compound due to high temperature interaction. The XPS of Ce(3d) and Zr(3d) spectra confirm the reduction of both Ce and Zr to lower valent states. The oxygen storage and release capacity of the Ce0.5Zr0.5O2 compound was confirmed by analyzing the reduction of Ce4+ and Zr4+ with high temperature gas interaction. When Ce0.5Zr0.5O2 (which is same as Ce2Zr2O8) in cubic fluorite structure was subjected to strong shock, it changed to pyrochlore (Ce2Zr2O7) structure by releasing oxygen and on further heating it changed to Ce2Zr2O6.3 which is also crystallized in pyrochlore structure by further releasing oxygen. If this heating is carried out in presence of argon test gas, fluorite structure can easily change to pyrochlore Ce2Zr2O6.3 structure, which is a good electrical conductor. Due to its oxygen storage capability (OSC) and redox (Ce4+/Ce3+) properties, Ce0.5Zr0.5O2 had been used as oxygen storage material in three-way-catalyst. Importance of these reactions is that the O2 gas released from the compound will react with gas released from the heat shield materials, like NOx, CO and hydrocarbon (HCs) species which results in reduction of temperature in the shock layer of the re-entry space vehicle. The compound Ce0.5Zr0.5O2 changes its crystal structure from fluorite to pyrochlore phase in presence of shock heated test gas. The results presented in these two Chapters are first of their kind, which demonstrates the surface catalytic reactions. In Chapter 8, we present preliminary results of the oxygen recombination on the surface of heat shield material procured from Indian Space Research Organization (ISRO) used as TPS in re-entry space capsule (Space capsule Recovery Experiment SRE-1) and on thin film SiO2 deposited on silicon substrate. The formation of SiO between the junctions of SiO2/Si was confirmed using XPS study when shock exposed oxygen reacted on these materials. The surface morphology of the ablated SiO2 film was studied using SEM. The damage induced due to impact of shock wave in presence of oxygen gas was analyzed using Focused Ion Beam (FIB) microscope. The results reveal the damage on the surface of SiO2 film and also in the cross-section of the film. We are further investigating use of FIB, particularly related to residual stress developed on thin films due to high pressure and high temperature shock wave interaction. In Chapter 9, conclusions on the performance of FPST, synthesis of high temperature materials, catalytic and non-catalytic surface reactions on the high temperature material due to shock-heated test gases are presented. Possible scope for future studies is also addressed in this Chapter.
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"Shock Metamorphism in Ordinary Chondrites: Constraining Pressure and Temperature History." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40325.

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abstract: Shock metamorphism in meteorites constrains the impact histories of asteroids and planets. Shock-induced high-pressure (HP) minerals can provide more precise estimates of shock conditions than shock-induced deformation effects. In this research, I use shock features, particularly HP minerals, in ordinary-chondrite samples to constrain not only shock pressures but also the pressure-temperature-time (P-T-t) paths they experienced. Highly shocked L5/6 chondrites Acfer 040, Mbale, NWA 091 and Chico and LL6 chondrite NWA 757 were used to investigate a variety of shock pressures and post-shock annealing histories. NWA 757 is the only highly shocked LL chondrite that includes abundant HP minerals. The assemblage of ringwoodite and majoritic garnet indicates an equilibration shock pressure of ~20 GPa, similar to many strongly shocked L chondrites. Acfer 040 is one of the only two chondrite samples with bridgmanite (silicate perovskite), suggesting equilibration pressure >25 GPa. The bridgmanite, which is unstable at low-pressure, was mostly vitrified during post-shock cooling. Mbale demonstrates an example of elevated post-shock temperature resulting in back-transformation of ringwoodite to olivine. In contrast, majoritic garnet in Mbale survives as unambiguous evidence of strong shock. In these two samples, HP minerals are exclusively associated with shock melt, indicating that elevated shock temperatures are required for rapid mineral transformations during the transient shock pulse. However, elevated post-shock temperatures can destroy HP minerals: in temperature sequence from bridgmanite to ringwoodite then garnet. NWA 091 and Chico are impact melt breccias with pervasive melting, blackening of silicates, recrystallization of host rock but no HP minerals. These features indicate near whole-rock-melting conditions. However, the elevated post-shock temperatures of these samples has annealed out HP signatures. The observed shock features result from a complex P-T-t path and may not directly reflect the peak shock pressure. Although HP minerals provide robust evidence of high pressure, their occurrence also requires high shock temperatures and rapid cooling during the shock pulse. The most highly shocked samples lack HP signatures but have abundant high-temperature features formed after pressure release.
Dissertation/Thesis
Doctoral Dissertation Geological Sciences 2016
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Books on the topic "High temperature shock"

1

Chen, Yanan. High Temperature Shock Technology. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8124-1.

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Brun, Raymond, ed. High Temperature Phenomena in Shock Waves. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1.

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Brun, Raymond. High Temperature Phenomena in Shock Waves. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012.

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Singh, N. Studies on equatorial shock formation during plasmaspheric refilling: Grant NAGW-2128. [Washington, DC: National Aeronautics and Space Administration, 1993.

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P, Raĭzer I͡U, ed. Physics of shock waves and high-temperature hydrodynamic phenomena. Mineola, N.Y: Dover Publications, 2002.

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American Physical Society Topical Conference on Shock Waves in Condensed Matter (4th 1985 Spokane, Wash.). Shock waves in condensed matter. New York: Plenum Press, 1986.

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Davison, Lee. High-Pressure Shock Compression of Solids V: Shock Chemistry with Applications to Meteorite Impacts. New York, NY: Springer New York, 2003.

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Ill.) American Physical Society Topical Conference on Shock Compression of Condensed Matter (2011 Chicago. Shock compression of condensed matter--2011: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter, held in Chicago Illinois, USA, June 26-July 1, 2011. Edited by Elert Mark and American Physical Society. Topical Group on Shock Compression of Condensed Matter. Melville, N.Y: American Institute of Physics, 2012.

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American, Physical Society Topical Conference on Shock Compression of Condensed Matter (12th 2001 Atlanta Ga ). Shock compression of condensed matter--2001: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter held in Atlanta, Georgia, June 24-29, 2001. Melville, N.Y: American Institute of Physics, 2002.

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Brun, Raymond. High Temperature Phenomena in Shock Waves. Springer, 2014.

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Book chapters on the topic "High temperature shock"

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Raines, A. A., and F. G. Tcheremissine. "Structure of Shock Waves." In High Temperature Phenomena in Shock Waves, 231–69. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_7.

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Nakai, Akira. "Proteostasis and Adaptation to High Temperature Stress." In Heat Shock Factor, 3–29. Tokyo: Springer Japan, 2016. http://dx.doi.org/10.1007/978-4-431-55852-1_1.

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Huo, W. M., M. Panesi, and T. E. Magin. "Ionization Phenomena behind Shock Waves." In High Temperature Phenomena in Shock Waves, 149–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_5.

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Perrin, M. Y., Ph Riviére, and A. Soufiani. "Radiation Phenomena behind Shock Waves." In High Temperature Phenomena in Shock Waves, 193–230. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_6.

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Lago, V., A. Chpoun, and B. Chanetz. "Shock Waves in Hypersonic Rarefied Flows." In High Temperature Phenomena in Shock Waves, 271–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_8.

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Kumar, S., H. Olivier, and J. Ballmann. "Numerical study of thermochemical relaxation phenomena in high-temperature nonequilibrium flows." In Shock Waves, 677–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-85168-4_109.

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Ginsztler, J. "Experimental Analysis of Thermal Shock." In Mechanical Behaviour of Materials at High Temperature, 431–41. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1714-9_23.

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Capitelli, M., D. Bruno, G. Colonna, G. D’Ammando, A. D’Angola, D. Giordano, C. Gorse, A. Laricchiuta, and S. Longo. "Thermodynamic Properties of Gases behind Shock Waves." In High Temperature Phenomena in Shock Waves, 11–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_2.

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Brun, R. "General Introduction." In High Temperature Phenomena in Shock Waves, 1–9. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_1.

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Kustova, E. V., and E. A. Nagnibeda. "Non-equilibrium Kinetics and Transport Properties behind Shock Waves." In High Temperature Phenomena in Shock Waves, 59–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25119-1_3.

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Conference papers on the topic "High temperature shock"

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Braun-Unkhoff, M., A. Kurz, and P. Frank. "High temperature pyrolysis of vinylacetylene." In Current topics in shock waves 17th international symposium on shock waves and shock tubes Bethlehem, Pennsylvania (USA). AIP, 1990. http://dx.doi.org/10.1063/1.39380.

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Thyagarajan, K., and K. A. Bhaskaran. "High temperature gas phase oxidation kinetics of benzene." In Current topics in shock waves 17th international symposium on shock waves and shock tubes Bethlehem, Pennsylvania (USA). AIP, 1990. http://dx.doi.org/10.1063/1.39375.

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Ree, Francis H. "Modeling high-pressure and high-temperature phase changes in bulk carbon." In Shock compression of condensed matter. AIP, 2000. http://dx.doi.org/10.1063/1.1303421.

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Patterson, P. M., J. W. Sutherland, and R. B. Klemm. "High temperature study of the reaction of O(3P)+NH3." In Current topics in shock waves 17th international symposium on shock waves and shock tubes Bethlehem, Pennsylvania (USA). AIP, 1990. http://dx.doi.org/10.1063/1.39372.

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Yoo, C. S., N. C. Holmes, M. Ross, and E. See. "Shock temperature measurements of iron to 350 GPa." In High-pressure science and technology—1993. AIP, 1994. http://dx.doi.org/10.1063/1.46194.

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Seifter, A., M. Grover, D. B. Holtkamp, J. R. Payton, P. Rodriguez, William D. Turley, and A. W. Obst. "Low-temperature measurements on shock-loaded tin." In 26th International Congress on High-Speed Photography and Photonics, edited by Dennis L. Paisley, Stuart Kleinfelder, Donald R. Snyder, and Brian J. Thompson. SPIE, 2005. http://dx.doi.org/10.1117/12.571449.

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Arrieta, Hernan V. "High and low temperature dynamic testing of advanced materials." In Shock compression of condensed matter. AIP, 2000. http://dx.doi.org/10.1063/1.1303652.

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Petter, Samuel J., Kyle P. Lynch, Paul Farias, Seth Spitzer, Thomas Grasser, and Justin L. Wagner. "Early Experiments on Shock-Particle Interactions in the High-Temperature Shock Tube." In AIAA Scitech 2020 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2020. http://dx.doi.org/10.2514/6.2020-0622.

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Hokamoto, Kazuyuki. "Possibility of making polycrystalline diamond using high-temperature shock consolidation technique." In Shock compression of condensed matter. AIP, 2000. http://dx.doi.org/10.1063/1.1303585.

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Lamas von Sohsten, Vinícius, Gabriel Afonso Pichorim, Pedro Paulo Batista de Araújo, Heidi Korzenowski, George Marinho, and Paulo Toro. "OBLIQUE SHOCK WAVE FOR AIR AT HIGH TEMPERATURE." In 26th International Congress of Mechanical Engineering. ABCM, 2021. http://dx.doi.org/10.26678/abcm.cobem2021.cob2021-1661.

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Reports on the topic "High temperature shock"

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Tomar, Vikas. Understanding Nanoscale Thermal Conduction an Mechanical Strength Correlation in High Temperature Ceramics with Improved Thermal Shock Resistance for Aerospace Applications. Fort Belvoir, VA: Defense Technical Information Center, August 2012. http://dx.doi.org/10.21236/ada581368.

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Blum, Abraham, Henry T. Nguyen, and N. Y. Klueva. The Genetics of Heat Shock Proteins in Wheat in Relation to Heat Tolerance and Yield. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568105.bard.

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Fifty six diverse spring wheat cultivars were evaluated for genetic variation and heritability for thermotolerance in terms of cell-membrane stability (CMS) and triphenyl tetrazolium chloride (TTC) reduction. The most divergent cultivars for thermotolerance (Danbata-tolerant and Nacozari-susceptible) were crossed to develop an F8 random onbred line (RIL) population. This population was evaluated for co-segragation in CMS, yield under heat stress and HSP accumulation. Further studies of thermotolerance in relations to HSP and the expression of heterosis for growth under heat stress were performed with F1 hybrids of wheat and their parental cultivars. CMS in 95 RILs ranged from 76.5% to 22.4% with 71.5% and 31.3% in Danbata and Nacozari, respectively. The population segregated with a normal distribution across the full range of the parental values. Yield and biomass under non-stress conditions during the normal winter season at Bet Dagan dit not differ between the two parental cultivar, but the range of segregation for these traits in 138 RILs was very high and distinctly transgressive with a CV of 35.3% and 42.4% among lines for biomass and yield, respectively. Mean biomass and yield of the population was reduced about twofold when grown under the hot summer conditions (irrigated) at Bet Dagan. Segregation for biomass and yield was decreased relative to the normal winter conditions with CV of 20.2% and 23.3% among lines for biomass and yield, respectively. However, contrary to non-stress conditions, the parental cultivars differed about twofold in biomass and yield under heat stress and the population segregated with normal distribution across the full range of this difference. CMS was highly and positively correlated across 79 RILs with biomass (r=0.62**) and yield (r=0.58**) under heat stress. No such correlation was obtained under the normal winter conditions. All RILs expressed a set of HSPs under heat shock (37oC for 2 h). No variation was detected among RILs in high molecular weight HSP isoforms and they were similar to the patterns of the parental cultivars. There was a surprisingly low variability in low molecular weight HSP isoforms. Only one low molecular weight and Nacozari-specific HSP isoform (belonging to HSP 16.9 family) appeared to segregate among all RILs, but it was not quantitatively correlated with any parameter of plant production under heat stress or with CMS in this population. It is concluded that this Danbata/Nacozari F8 RIL population co-segregated well for thermotolerance and yield under heat stress and that CMS could predict the relative productivity of lines under chronic heat stress. Regretfully this population did not express meaningful variability for HSP accumulation under heat shock and therefore no role could be seen for HSP in the heat tolerance of this population. In the study of seven F1 hybrids and their parent cultivars it was found that heterosis (superiority of the F1 over the best parent) for CMs was generally lower than that for growth under heat stress. Hybrids varied in the rate of heterosis for growth at normal (15o/25o) and at high (25o/35o) temperatures. In certain hybrids heterosis for growth significantly increased at high temperature as compared with normal temperature, suggesting temperature-dependent heterosis. Generally, under normal temperature, only limited qualitative variation was detected in the patterns of protein synthesis in four wheat hybrids and their parents. However, a singular protein (C47/5.88) was specifically expressed only in the most heterotic hybrid at normal temperature but not in its parent cultivars. Parental cultivars were significantly different in the sets of synthesized HSP at 37o. No qualitative changes in the patterns of protein expression under heat stress were correlated with heterosis. However, a quantitative increase in certain low molecular weight HSP (mainly H14/5.5 and H14.5.6, belonging to the HSP16.9 family) was positively associated with greater heterosis for growth at high temperature. None of these proteins were correlated with CMS across hybrids. These results support the concept of temperature-dependent heterosis for growth and a possible role for HSP 16.9 family in this respect. Finally, when all experiments are viewed together, it is encouraging to find that genetic variation in wheat yield under chronic heat stress is associated with and well predicted by CMS as an assay of thermotolerance. On the other hand the results for HSP are elusive. While very low genetic variation was expressed for HSP in the RIL population, a unique low molecular weight HSP (of the HSP 16.9 family) could be associated with temperature dependant heterosis for growth.
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Hansen, Peter J., Zvi Roth, and Jeremy J. Block. Improving oocyte competence in dairy cows exposed to heat stress. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598163.bard.

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Original Objectives. The overall goal is to develop methods to increase pregnancy rate in lactating dairy cows exposed to heat stress through methods that minimize damage to the oocyte and embryo caused by heat stress. Objectives were as follows: (1) examine the protective effects of melatonin on developmental competence of oocytes exposed to elevated temperature in vitro; (2) test whether melatonin feeding can improve developmental competence of oocytes in vivo and, if so, whether effects are limited to the summer or also occur in the absence of heat stress; and (3) evaluate the effectiveness of improving fertility by facilitating follicular turnover in the summer and winter. Revised Objectives. (1) Examine protective effects of melatonin and follicular fluid on developmental competence of oocytes exposed to elevated temperature in vitro; (2) examine the protective effects of melatonin on developmental competence of embryos exposed to elevated temperature in vitro; (3) evaluate effectiveness of improving fertility by administering human chorionicgonadotropin (hCG) to increase circulating concentrations of progesterone and evaluate whether response to hCG depends upon genotype for four mutations reported to be related to cow fertility; and (4) identify genes with allelic variants that increase resistance of embryos to heat shock. Background. The overall hypothesis is that pregnancy success is reduced by heat stress because of damage to the oocyte and cleavage-stage embryo mediated by reactive oxygen species (ROS), and that fertility can be improved by provision of antioxidants or by removing follicles containing oocytes damaged by heat stress. During the study, additional evidence from the literature indicated the potential importance of treatment with chorionicgonadotropin to increase fertility of heat- stressed cows and results from other studies in our laboratories implicated genotype as an important determinant of cow fertility. Thus, the project was expanded to evaluate hCG treatment and to identify whether fertility response to hCG depended upon single nucleotide polymorphisms (SNP) in genes implicated as important for cow fertility. We also evaluated whether a SNP in a gene important for cellular resistance to heat stress (HSPA1L, a member of the heat shock protein 70 family) is important for embryonic resistance to elevated temperature. Major conclusions, solutions & achievements. Results confirmed that elevated temperature increases ROS production by the oocyte and embryo and that melatonin decreases ROS. Melatonin reduced, but did not completely block, damaging effects of heat shock on the oocyte and had no effect on development of the embryo. Melatonin was protective to the oocyte at 0.1-1 μM, a concentration too high to be achieved in cows. It was concluded that melatonin is unlikely to be a useful molecule for increasing fertility of heat-stressed cows. Treatment with hCG at day 5 after breeding increased first-service pregnancy rate for primiparous cows but not for multiparous cows. Thus, hCG could be useful for increasing fertility in first-parity cows. The effectiveness of hCG depended upon genotype for a SNP in COQ9, a gene encoding for a mitochondrial-function protein. This result points the way to future efforts to use genetic information to identify populations of cows for which hormone treatments will be effective or ineffective. The SNP in HSPA1L was related to embryonic survival after heat shock. Perhaps, genetic selection for mutations that increase cellular resistance to heat shock could be employed to reduce effects of heat stress on fertility. Implications, both scientific and agricultural. This project has resulted in abandonment of one possible approach to improve fertility of the heat-stressed cow (melatonin therapy) while also leading to a method for improving fertility of primiparous cows exposed to heat stress (hCG treatment) that can be implemented on farms today. Genetic studies have pointed the way to using genetic information to 1) tailor hormonal treatments to cow populations likely to respond favorably and 2) select animals whose embryos have superior resistance to elevated body temperatures.
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Lurie, Susan, David R. Dilley, Joshua D. Klein, and Ian D. Wilson. Prestorage Heat Treatment to Inhibit Chilling Injury and Delay Ripening in Tomato Fruits. United States Department of Agriculture, June 1993. http://dx.doi.org/10.32747/1993.7568108.bard.

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The research had two specific goals; (1) to develop and optimize a postharvest heat treatment and characterize the response of tomato to the heat and subsequent cold storage, and (2) to investigate the involvement of heat shock proteins (HSP) in resistance to chilling injury. For the first goal we have investigated many time-temperature treatments using dry heat and found that 48 h at 38oC is optimum for Israeli cultivars, while 48 h at 42oC worked better for American cultivars in preventing chilling injury. We have also compared hot water to hot air and found hot water to be effective, but less so than hot air. Membrane lipid composition in relation to chilling injury was investigated after hot water and hot air treatments. Investigation of fruit ripening found that mRNAs of ripening-related genes were inhibited by high temperature, but recovered during the subsequent storage period and allowed normal ripening to proceed. Sensory studies showed no difference in the taste of heated or nonheated fruit. Following the production of HSP in heated and stored fruit allowed us to determine that during low temperature storage the HSP remained present in the fruit tissue, and their presence was correlated with resistance to chilling injury. HSP clones have been isolated by both differential screening of a cDNA library of heated and chilled tomatoes (Israel) and by mRNA differential display (United States). These clones are being characterized.
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Firon, Nurit, Prem Chourey, Etan Pressman, Allen Hartwell, and Kenneth J. Boote. Molecular Identification and Characterization of Heat-Stress-Responsive Microgametogenesis Genes in Tomato and Sorghum - A Feasibility Study. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7591741.bard.

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Exposure to higher than optimal temperatures - heat-stress (HS) - is becoming increasingly common to all crop plants worldwide. Heat stress coinciding with microgametogenesis, especially during the post-meiotic phase that is marked by starch biosynthesis, is often associated with starch-deficient pollen and male sterility and ultimately, greatly reduced crop yields. The molecular basis for the high sensitivity of developing pollen grains, on one hand, and factors involved in pollen heat-tolerance, on the other, is poorly understood. The long-term goal of this project is to provide a better understanding of the genes that control pollen quality under heat-stress conditions. The specific objectives of this project were: (1) Determination of the threshold heat stress temperature(s) that affects tomato and sorghum pollen quality whether: a) Chronic mild heat stress conditions (CMHS), or b) Acute heat stress (AHS). (2) Isolation of heat-responsive, microgametogenesis-specific sequences. During our one-year feasibility project, we have accomplished the proposed objectives as follows: Objectrive 1: We have determined the threshold HS conditions in tomato and sorghum. This was essential for achieving the 2nd objective, since our accumulated experience (both Israeli and US labs) indicate that when temperature is raised too high above "threshold HS levels" it may cause massive death of the developing pollen grains. Above-threshold conditions have additional major disadvantages including the "noise" caused by induced expression of genes involved in cell death and masking of the differences between heatsensitive and heat-tolerant pollen grains. Two different types of HS conditions were determined: a) Season-long CMHS conditions: 32/26°C day/night temperatures confirmed in tomato and 36/26°C day maximum/night minimum temperatures in sorghum. b) Short-term AHS: In tomato, 2 hour exposure to 42-45°C (at 7 to 3 days before anthesis) followed by transfer to 28/22±2oC day/night temperatures until flower opening and pollen maturation, caused 50% reduced germinating pollen in the heat-sensitive 3017 cv.. In sorghum, 36/26°C day/night temperatures 10 to 5 days prior to panicle emergence, occurring at 35 days after sowing (DAS) in cv. DeKalb28E, produced starch-deficient and sterile pollen. Objective 2: We have established protocols for the high throughput transcriptomic approach, cDNA-AFLP, for identifying and isolating genes exhibiting differential expression in developing microspores exposed to either ambient or HS conditions and created a databank of HS-responsivemicrogametogenesis-expressed genes. A subset of differentially displayed Transcript-Derived Fragments (TDFs) that were cloned and sequenced (35 & 23 TDFs in tomato and sorghum, respectively) show close sequence similarities with metabolic genes, genes involved in regulation of carbohydrate metabolism, genes implicated in thermotolerance (heat shock proteins), genes involved in long chain fatty acids elongation, genes involved in proteolysis, in oxidation-reduction, vesicle-mediated transport, cell division and transcription factors. T-DNA-tagged Arabidopsis mutants for part of these genes were obtained to be used for their functional analysis. These studies are planned for a continuation project. Following functional analyses of these genes under HS – a valuable resource of genes, engaged in the HS-response of developing pollen grains, that could be modulated for the improvement of pollen quality under HS in both dicots and monocots and/or used to look for natural variability of such genes for selecting heat-tolerant germplasm - is expected.
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6

Hansen, Peter J., and Zvi Roth. Use of Oocyte and Embryo Survival Factors to Enhance Fertility of Heat-stressed Dairy Cattle. United States Department of Agriculture, August 2011. http://dx.doi.org/10.32747/2011.7697105.bard.

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The overall goal was to identify survival factors that can improve pregnancy success following insemination or embryo transfer in lactating dairy cows exposed to heat stress. First, we demonstrated that oocytes are actually damaged by elevated temperature in the summer. Then we tested two thermoprotective molecules for their effect on oocyte damage caused by heat shock. One molecule, ceramide was not thermoprptective. Another, insulin-like growth factor-1 (IGF) reduced the effects of heat shock on oocyte apoptosis and oocyte cleavage when added during maturation. We also used lactating cows exposed to heat stress to determine whether bovine somatotropin (bST), which increases IGF1 levels in vivo, would improve fertility in summer. Cows treated with bST received a single injection at 3 days before insemination. Controls received no additional treatment. Treatment with bST did not significantly increase the proportion of inseminated cows diagnosed pregnant although it was numerically greater for the bST group (24.2% vs 17.8%, 124–132 cows per group). There was a tendency (p =0.10) for a smaller percent of control cows to have high plasma progesterone concentrations (≥ 1 ng/ml) at Day 7 after insemination than for bST-treated cows (72.6 vs 81.1%). When only cows that were successfully synchronized were considered, the magnitude of the absolute difference in the percentage of inseminated cows that were diagnosed pregnant between bST and control cows was reduced (24.8 vs 22.4% pregnant for bST and control). Results failed to indicate a beneficial effect of bST treatment on fertility of lactating dairy cows. In another experiment, we found a tendency for addition of IGF1 to embryo culture medium to improve embryonic survival after embryo transfer when the experiment was done during heat stress but not when the experiment was done in the absence of heat stress. Another molecule tested, granulocyte-macrophage colony-stimulating factor (GM-CSF; also called colony-stimulating factor-2), improved embryonic survival in the absence of heat stress. We also examined whether heat shock affects the sperm cell. There was no effect of heat shock on sperm apoptosis (programmed cell death) or on sperm fertilizing ability. Therefore, effects of heat shock on sperm function after ejaculation if minimal. However, there were seasonal changes in sperm characteristics that indicates that some of the decrease in dairy cow fertility during the summer in Israel is due to using semen of inferior quality. Semen was collected from five representative bulls throughout the summer (August and September) and winter (December and January). There were seasonal differences in ion concentration in seminal plasma and in the mRNA for various ion channels known to be involved in acrosome reactions. Furthermore, the proportion of sperm cells with damaged acrosomes was higher in post-thaw semen collected in the summer than in its counterpart collected in winter (54.2 ± 3.5% vs. 51.4 ± 1.9%, respectively; P < 0.08Further examination is required to determine whether such alterations are involved in the low summer fertility of dairy cows.
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7

Chen, Junping, Zach Adam, and Arie Admon. The Role of FtsH11 Protease in Chloroplast Biogenesis and Maintenance at Elevated Temperatures in Model and Crop Plants. United States Department of Agriculture, May 2013. http://dx.doi.org/10.32747/2013.7699845.bard.

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specific objectives of this proposal were to: 1) determine the location, topology, and oligomerization of FtsH11 protease; 2) identify the substrate/s of FtsH11 and the downstream components involved in maintaining thermostability of chloroplasts; 3) identify new elements involved in FtsH11 protease regulatory network related to HT adaptation processes in chloroplast; 4) Study the role of FtsH11 homologs from crop species in HT tolerance. Background to the topic: HT-tolerant varieties that maintain high photosynthetic efficiency at HT, and cope better with daily and seasonal temperature fluctuations are in great need to alleviate the effect of global warming on food production. Photosynthesis is a very complex process requiring accurate coordination of many complex systems and constant adjustments to the changing environments. Proteolytic activities mediated by various proteases in chloroplast are essential part of this process and critical for maintaining normal chloroplast functions under HT. However, little is known about mechanisms that contribute to adaptation of photosynthetic processes to HT. Our study has shown that a chloroplast-targeted Arabidopsis FtsH11 protease plays an essential and specific role in maintaining thermostability of thylakoids and normal photosynthesis at moderate HT. We hypothesized that FtsH11 homologs recently identified in other plant species might have roles similarly to that of AtFtsH1. Thus, dissecting the underlying mechanisms of FtsH11 in the adaptation mechanisms in chloroplasts to HT stress and other elements involved will aid our effort to produce more agricultural products in less favorable environments. Major conclusions, solutions, achievements - Identified the chloroplast inner envelope membrane localization of FtsH11. - Revealed a specific association of FtsH11 with the a and b subunits of CPN60. - Identified the involvement of ARC6, a protein coordinates chloroplast division machineries in plants, in FtsH11 mediated HT adaptation process in chloroplast. -Reveal possible association of a polyribonucleotide nucleotidyltransferase (cpPNPase), coded by At3G03710, with FtsH11 mediated HT adaptation process in chloroplast. - Mapped 4 additional loci in FtsH11 mediated HT adaptation network in chloroplast. - Demonstrated importance of the proteolytic activity of FtsH11 for thermotolerance, in addition to the ATPase activity. - Demonstrated a conserved role of plant FtsH11 proteases in chloroplast biogenesis and in maintaining structural and functional thermostability of chloroplast at elevated temperatures. Implications, both scientific and agricultural:Three different components interacting with FtsH11 were identified during the course of this study. At present, it is not known whether these proteins are directly involved in FtsH11mediated thermotolerance network in chloroplast and/or how these elements are interrelated. Studies aiming to connect the dot among biological functions of these networks are underway in both labs. Nevertheless, in bacteria where it was first studied, FtsH functions in heat shock response by regulating transcription level of σ32, a heat chock factor regulates HSPsexpression. FtsH also involves in control of biosynthesis of membrane components and quality control of membrane proteins etc. In plants, both Arc 6 and CPN60 identified in this study are essential in chloroplast division and developments as mutation of either one impairs chloroplast division in Arabidopsis. The facts that we have found the specific association of both α and β CPN60 with FtsH11 protein biochemically, the suppression/ enhancement of ftsh11 thermosensitive phenotype by arc6 /pnp allele genetically, implicate inter-connection of these networks via FtsH11 mediated network(s) in regulating the dynamic adaptation processes of chloroplast to temperature increases at transcriptional, translational and post-translational levels. The conserved role of FtsH11 proteases in maintaining thermostability of chloroplast at HT demonstrated here provides a foundation for improving crop photosynthetic performance at high temperatures.
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8

Droby, Samir, Michael Wisniewski, Ron Porat, and Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7594390.bard.

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To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.
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9

Miller, Gad, and Jeffrey F. Harper. Pollen fertility and the role of ROS and Ca signaling in heat stress tolerance. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598150.bard.

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The long-term goal of this research is to understand how pollen cope with stress, and identify genes that can be manipulated in crop plants to improve reproductive success during heat stress. The specific aims were to: 1) Compare heat stress dependent changes in gene expression between wild type pollen, and mutants in which pollen are heat sensitive (cngc16) or heat tolerant (apx2-1). 2) Compare cngc16 and apx2 mutants for differences in heat-stress triggered changes in ROS, cNMP, and Ca²⁺ transients. 3) Expand a mutant screen for pollen with increased or decreased thermo-tolerance. These aims were designed to provide novel and fundamental advances to our understanding of stress tolerance in pollen reproductive development, and enable research aimed at improving crop plants to be more productive under conditions of heat stress. Background: Each year crop yields are severely impacted by a variety of stress conditions, including heat, cold, drought, hypoxia, and salt. Reproductive development in flowering plants is highly sensitive to hot or cold temperatures, with even a single hot day or cold night sometimes being fatal to reproductive success. In many plants, pollen tube development and fertilization is often the weakest link. Current speculation about global climate change is that most agricultural regions will experience more extreme environmental fluctuations. With the human food supply largely dependent on seeds, it is critical that we consider ways to improve stress tolerance during fertilization. The heat stress response (HSR) has been intensively studied in vegetative tissues, but is poorly understood during reproductive development. A general paradigm is that HS is accompanied by increased production of reactive oxygen species (ROS) and induction of ROS-scavenging enzymes to protect cells from excess oxidative damage. The activation of the HSR has been linked to cytosolic Ca²⁺ signals, and transcriptional and translational responses, including the increased expression of heat shock proteins (HSPs) and antioxidative pathways. The focus of the proposed research was on two mutations, which have been discovered in a collaboration between the Harper and Miller labs, that either increase or decrease reproductive stress tolerance in a model plant, Arabidopsis thaliana (i.e., cngc16--cyclic nucleotide gated channel 16, apx2-1--ascorbate peroxidase 2,). Major conclusions, solutions, achievements. Using RNA-seq technology, the expression profiles of cngc16 and apx2 pollen grains were independently compared to wild type under favourable conditions and following HS. In comparison to a wild type HSR, there were 2,776 differences in the transcriptome response in cngc16 pollen, consistent with a model in which this heat-sensitive mutant fails to enact or maintain a normal wild-type HSR. In a comparison with apx2 pollen, there were 900 differences in the HSR. Some portion of these 900 differences might contribute to an improved HSR in apx2 pollen. Twenty-seven and 42 transcription factor changes, in cngc16 and apx2-1, respectively, were identified that could provide unique contributions to a pollen HSR. While we found that the functional HS-dependent reprogramming of the pollen transcriptome requires specific activity of CNGC16, we identified in apx2 specific activation of flavonol-biosynthesis pathway and auxin signalling that support a role in pollen thermotolerance. Results from this study have identified metabolic pathways and candidate genes of potential use in improving HS tolerance in pollen. Additionally, we developed new FACS-based methodology that can quantify the stress response for individual pollen in a high-throughput fashion. This technology is being adapted for biological screening of crop plant’s pollen to identify novel thermotolerance traits. Implications, both scientific and agricultural. This study has provided a reference data on the pollen HSR from a model plant, and supports a model that the HSR in pollen has many differences compared to vegetative cells. This provides an important foundation for understanding and improving the pollen HSR, and therefor contributes to the long-term goal of improving productivity in crop plants subjected to temperature stress conditions. A specific hypothesis that has emerged from this study is that pollen thermotolerance can be improved by increasing flavonol accumulation before or during a stress response. Efforts to test this hypothesis have been initiated, and if successful have the potential for application with major seed crops such as maize and rice.
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10

Cohen, Roni, Kevin Crosby, Menahem Edelstein, John Jifon, Beny Aloni, Nurit Katzir, Haim Nerson, and Daniel Leskovar. Grafting as a strategy for disease and stress management in muskmelon production. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7613874.bard.

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The overall objective of this research was to elucidate the horticultural, pathological, physiological and molecular factors impacting melon varieties (scion) grafted onto M. cannonballus resistant melon and squash rootstocks. Specific objectives were- to compare the performance of resistant melon germplasm (grafted and non-grafted) when exposed to M. cannoballus in the Lower Rio Grande valley and the Wintergarden, Texas, and in the Arava valley, Israel; to address inter-species relationships between a Monosporascus resistant melon rootstock and susceptible melon scions in terms of fruit-set, fruit quality and yield; to study the factors which determine the compatibility between the rootstock and the scion in melon; to compare the responses of graft unions of differing compatibilities under disease stress, high temperatures, deficit irrigation, and salinity stress; and to investigate the effect of rootstock on stress related gene expression in the scion. Some revisions were- to include watermelon in the Texas investigations since it is much more economically important to the state, and also to evaluate additional vine decline pathogens Didymella bryoniae and Macrophomina phaseolina. Current strategies for managing vine decline rely heavily on soil fumigation with methyl bromide, but restrictions on its use have increased the need for alternative management strategies. Grafting of commercial melon varieties onto resistant rootstocks with vigorous root systems is an alternative to methyl bromide for Monosporascus root rot/vine decline (MRR/VD) management in melon production. Extensive selection and breeding has already produced potential melon rootstock lines with vigorous root systems and disease resistance. Melons can also be grafted onto Cucurbita spp., providing nonspecific but efficient protection from a wide range of soil-borne diseases and against some abiotic stresses, but compatibility between the scion and the rootstock can be problematic. During the first year experiments to evaluate resistance to the vine decline pathogens Monosporascus cannonballus, Didymella bryoniae, and Macrophomina phaseolina in melon and squash rootstocks proved the efficacy of these grafted plants in improving yield and quality. Sugars and fruit size were better in grafted versus non-grafted plants in both Texas and Israel. Two melons (1207 and 124104) and one pumpkin, Tetsukabuto, were identified as the best candidate rootstocks in Texas field trials, while in Israel, the pumpkin rootstock RS59 performed best. Additionally, three hybrid melon rootstocks demonstrated excellent resistance to both M. cannonballus and D. bryoniae in inoculated tests, suggesting that further screening for fruit quality and yield should be conducted. Experiments with ABA in Uvalde demonstrated a significant increase in drought stress tolerance and concurrent reduction in transplant shock due to reduced transpiration for ‘Caravelle’ plants. In Israel, auxin was implicated in reducing root development and contributing to increased hydrogen peroxide, which may explain incompatibility reactions with some squash rootstocks. However, trellised plants responded favorably to auxin (NAA) application at the time of fruit development. Gene expression analyses in Israel identified several cDNAs which may code for phloem related proteins, cyclins or other factors which impact the graft compatibility. Manipulation of these genes by transformation or traditional breeding may lead to improved rootstock cultivars. Commercial applications of the new melon rootstocks as well as the ABA and TIBA growth regulators have potential to improve the success of grafted melons in both Israel and Texas. The disease resistance, fruit quality and yield data generated by the field trials will help producers in both locations to decide what rootstock/scion combinations will be best.
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