Journal articles: 'Thermo-stressed state'

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Goloshumova, V., and Yu Brodov. "The thermo-stressed state of Steam Turbine Rotors during plant start-up." International Journal of Energy Production and Management 1, no. 3 (June 20, 2016): 245–52. http://dx.doi.org/10.2495/eq-v1-n3-245-252.

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Pulyaev, I. S., and S. M. Pulyaev. "ACCOUNTING OF THE OWN THERMO-STRESSED STATE OF THE SOLID CONCRETE WHILE PROVIDING THE REQUIRED CONSUMER PROPERTIES OF THE CRIMEAN BRIDGE CONSTRUCTIONS." Russian Automobile and Highway Industry Journal 15, no. 5 (November 11, 2018): 742–59. http://dx.doi.org/10.26518/2071-7296-2018-5-742-759.

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Introduction.The paper deals with the issues related to the determination and registration of the own thermo-stressed state formed in concrete while hardening and used to provide the required consumer properties in the Crimean bridge construction. Therefore, the problem is relevant because of the deadlines for the construction of such facility in the conditions of rough terrain and dry hot climate, and also taking into account the development of the unique non-class facilities in Russia.Materials and methods.The research is carried out in real-time conditions with the usage of modern measuring systems in practice, allowing to control the process of temperature and strength of hardening concrete in time. The modern computational and analytical complex, which is repeatedly tested under real conditions and by thermophysical calculations of hardening concrete of various class objects and massiveness, is used.Results.The results of the intrinsic thermo-stressed state of hardening concrete are presented in determining the permissible temperature gradient, which make it possible to accelerate the process of erecting the object with observance of the necessary consumer properties.Discussion and conclusion.The main conclusions and suggestions are made taking into account the intrinsic thermally stressed state of the concrete when it was hardened during the construction of the Crimean bridge. The paper would be interesting and useful for engineers and technical workers engaged in real production conditions, and for specialists dealing with the issues of the thermophysical processes occurring in concrete hardening and with the problems of ensuring the high consumer concrete properties in structures.

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Efimova, A. R., S. A. Vasilenko, and V. V. Bychkova. "CCP maneuverability increasing algorithm realized on DCS with the metal allowable thermo-stressed state provision." Journal of Physics: Conference Series 1679 (November 2020): 052010. http://dx.doi.org/10.1088/1742-6596/1679/5/052010.

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Zhang, Xiaolong, and Zheng Zhong. "Thermo-Chemo-Elasticity Considering Solid State Reaction and the Displacement Potential Approach to Quasi-Static Chemo-Mechanical Problems." International Journal of Applied Mechanics 10, no. 10 (December 2018): 1850112. http://dx.doi.org/10.1142/s1758825118501120.

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Engineering materials and structures represent complex behaviors when reacting to superposed influences of mechanical forces, high temperature, diffusion and reaction of chemicals, which could cause large internal stresses and further induce cracks or failure. To determine the material reliability and integrity, the multi-field interactions and stresses/strains evolutions need to be identified at first. We proposed a theory of thermo-chemo-elasticity considering solid state reactions between the solid phase and absorbed chemicals in a stressed-solid. Both diffusion–reaction induced chemical strains and thermal dilations are taken into account as functions of species concentration, reaction extent and temperature. The fully coupled conservation laws, constitutive equations and chemical kinetics are formulated for the initial-boundary problem. For isotropic solids, we developed a displacement potential approach for steady-state 3D problems of thermo-chemo-elasticity. Solutions can be found from particular solutions of displacement potential and homogeneous solution of thermo-chemo Lamé equation. This approach is also available for transient chemo-mechanical problems in thermal equilibrium providing that quasi-static conditions are introduced. We exemplified the model with a reaction-dominated problem of a core–shell structure subjected to chemo-mechanical loading and the results demonstrate the capability of the model in dealing with comprehensive influences of solid state reaction and species diffusion on solids.

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Weng, Lu Qian, Hai Lin Cao, Pavel V. Krivenko, Yue Guo, O. N. Petropavlovsky, V. I. Pushkar, and A. Yu Kovalchuk. "Modeling a Thermo-Stressed State of the Cast-in-Situ Low Carbon Footprint Alkali Activated Slag Cement Concrete Hardened under Hot Environment." Applied Mechanics and Materials 525 (February 2014): 482–90. http://dx.doi.org/10.4028/www.scientific.net/amm.525.482.

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Alkali activated slag cement concretes are low carbon footprint building mateirals, which can meet the requirements for sustainable development. The paper covers the results of modeling a thermo-stressed state of the cast-in-situ massive alkali activated slag cement concrete structure hardened under hot environment to meet the requirements for marine engineering application. The results show that alkali activated slag cement concretes have a substantially lower heat release than that of Portland, are suitable for cast-in-situ massive alkali activated slag cement concrete structure even under hot environment.

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Volkov, Ivan, Leonid Igumnov, Svetlana Litvinchuk, and Igor Vorobtsov. "Modeling dynamic deformation and failure of thin-walled structures under explosive loading." EPJ Web of Conferences 183 (2018): 03016. http://dx.doi.org/10.1051/epjconf/201818303016.

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In the framework of mechanics of damaged media, behavior of thin-walled structures under pulsed loading is described. Account is taken of the interaction of the processes of dynamic deformation and damage accumulation, as well as of the main characteristic features of the dynamic failure process: the multi-staged character, nonlinear summation of damage, stressed state history and accumulated damage level. The chosen system of equations of thermo-plasticity describes the main effects of dynamic deformation of the material for random deformation trajectories. The equations of state are based on the notions of yield surface and the principle of gradientality of the plastic strain rate vector. Evolutionary equations of damage accumulation are written for a scalar parameter of damage level and are based on energy principles. The effect of the stressed state type and the accumulated damage level on the processes of nucleation, growth and merging of microdefects is accounted for. Results of numerically modelling processes of dynamic deformation and failure of spherical and closed cylindrical shells with plane and hemispherical bottoms under single pulsed explosive loading are presented. The computational results are compared with experimental data.

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Gaidaichuk, Viktor, Liudmyla Shevchuk, and Olena Bilobrytska. "Influence of incompatibility of thermomechanical parameters of bearing layers of a bridge structure on its thermo-stressed state." Strength of Materials and Theory of Structures, no. 107 (October 29, 2021): 301–11. http://dx.doi.org/10.32347/2410-2547.2021.107.301-311.

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On the basis of the theory of thermoelasticity, the problem of the thermally stressed state of a two-layer fragment of a bridge structure, consisting of a metal base and an asphalt-concrete upper layer, under conditions of a change in the ambient temperature at different values of the coefficients of thermal linear expansion of the layers is considered. Using the finite element method, the fields of thermal stresses, deformations and displacements are constructed for various values of the thermomechanical characteristics of the layers. The analysis of the influence of the values of thermomechanical parameters on the stress-strain state of the system is carried out. It is shown that with an increase in the incompatibility of these characteristics, the intensities of stresses and strains increase. The zones of concentration of these functions are found. It is recommended to use materials with close values of their thermomechanical parameters when designing bridges to avoid their premature destruction.

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Semenov, Kirill, and Yuri Barabanshchikov. "Thermal Cracking Resistance in Massive Concrete Structures in the Winter Building Period." Applied Mechanics and Materials 725-726 (January 2015): 431–41. http://dx.doi.org/10.4028/www.scientific.net/amm.725-726.431.

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The article deals with issues of the thermal cracking resistance in massive concrete and reinforced concrete structures during the building period. The paper lists the calculation results of the NPP reactor foundation mat thermal stressed state and thermal cracking resistance. The research also considers the concrete hardening temperature influence on its thermo-physical and deformation characteristics. The deformation criterion is used to calculate the concrete thermal cracking resistance. In addition, the paper focuses on the assignment of safe concrete pouring technological parameters in the winter period. Furthermore, the article estimates the necessity of the structure peripheral electric heating during the building period.

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Serednytska, Kh I., and R. M. Martynyak. "Thermoelastic behavior of a bimaterial with interface crack filled with an incompressible fluid." Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, no. 1 (2019): 206–9. http://dx.doi.org/10.17721/1812-5409.2019/1.48.

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Thermo-stressed state of the bimaterial with the interfacial crack filled with an incompressible fluid is investigated. The bimaterial with zero Dundurs parameter is considered. The thermo-elastic problem is reduced to nonlinear systems of singular integro-differential equations for a temperature jump between the cracks faces and an opening crack. The pressure of the fluid is determined from the equation of the incompressible fluid. Using the method of successive approximations a numerical solution of the problem is constructed. The opening crack and temperature jump are determined by the finite sum for Chebyshev polynomials of the second kind. The coefficients for Chebyshev polynomials are determined from the system of linear algebraic equations. Having made numerical calculations, the dependences of the pressure of the fluid and the opening crack from the mechanical loads and density and direction of the heat flow have been constructed. The influence of fluid pressure on the stress intensity factor mode I are analyzed.

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Vorobiev, Yu, R. Rzadkowski, N. Ovcharova, and T. Berlizova. "Thermo-stressed state of a single-crystal cooled blade taking into account the axial orientation of the crystallographic axes." Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines 1, no. 33 (January 1, 2018): 18–22. http://dx.doi.org/10.20998/2078-9130.2018.33.151222.

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Kalynyak, B. M. "On some ways to achieve the absence of thermal stresses in an inhomogeneous through thickness infinite layer under stationary thermal loading." Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, no. 1 (2019): 66–69. http://dx.doi.org/10.17721/1812-5409.2019/1.14.

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A method for determining the characteristics of functional gradient materials (FGM) for providing zero thermal stresses in an infinite layer with given constant thermal loads is proposed. We assume that the classical convective conditions of heat transfer are given on the surfaces of the layer, the temperature field is stationary, the characteristics of the FGM are described by the model of a simple mixture, the characteristics of the thermo-stressed state and the material depend only on the transverse variable. Precise analytical expressions were obtained for the distribution of the concentration of one of the materials on the thickness of the layer in the absence of mass forces and heat sources, which provides zero longitudinal stresses.

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Kenzhegulov, Beket, Raigul Tuleuova, Aigul Myrzasheva, Nurgul Shazhdekeyeva, and Galymzhan Kabylkhamitov. "Mathematical modelling and development of a computational algorithm for the study of thermo-stressed state of a heat-resistant alloy." Periodicals of Engineering and Natural Sciences (PEN) 9, no. 4 (September 15, 2021): 214. http://dx.doi.org/10.21533/pen.v9i4.2304.

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Kovalchuk, Vitalii, Artur Onyshchenko, Olexander Fedorenko, Mykola Habrel, Bogdan Parneta, Oleh Voznyak, Ruslan Markul, Mariana Parneta, and Roman Rybak. "A comprehensive procedure for estimating the stressed-strained state of a reinforced concrete bridge under the action of variable environmental temperatures." Eastern-European Journal of Enterprise Technologies 2, no. 7 (110) (April 30, 2021): 23–30. http://dx.doi.org/10.15587/1729-4061.2021.228960.

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This paper reports the full-scale experimental measurements of temperature distribution over the surfaces of bridges' steel-concrete beams under the influence of positive and negative ambient temperatures. It has been established that the temperature is distributed unevenly along the vertical direction of a bridge's steel-concrete beam. It was found that the metal beam accepted higher temperature values. The maximum registered temperature difference between a metal beam and a reinforced concrete slab at positive ambient temperatures was +9.0 °C, and the minimum temperature difference was −2.1 °C. The mathematical models for calculating a temperature field and a thermally strained state of bridges' steel-concrete beams under the influence of variable climatic temperature changes in the environment have been improved, taking into consideration the uneven temperature distribution across a bridge's reinforced concrete beam. The possibility has been established to consider a one-dimensional problem or to apply the three-dimensional estimated problem schemes as the estimation schemes for determining the thermo-elastic state of reinforced concrete bridges. The temperature field and the stressed state of bridges' reinforced concrete beams were determined. It was found that the maximum stresses arise at the place where a metal beam meets a reinforced concrete slab. These stresses amount to 73.4 MPa at positive ambient temperatures, and 69.3 MPa at negative ambient temperatures. The amount of stresses is up to 35 % of the permissible stress values. The overall stressed-strained state of a bridge's reinforced concrete beams should be assessed at the joint action of temperature-induced climatic influences and loads from moving vehicles

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GENG, QIAN, and YUEMING LI. "ANALYSIS OF DYNAMIC AND ACOUSTIC RADIATION CHARACTERS FOR A FLAT PLATE UNDER THERMAL ENVIRONMENTS." International Journal of Applied Mechanics 04, no. 03 (September 2012): 1250028. http://dx.doi.org/10.1142/s1758825112500287.

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A study on vibration and acoustic radiation characters of an isotropic rectangular thin plate under thermal environments is presented in this paper. It is assumed that thermal loads caused by thermal environments just change the structure stress state. Thermal stresses induced by uniform temperature rise of the plate are determined with the thermo-elastic theory. Then the stress state is used in the following dynamic analysis as a pre-stressed factor. It is observed that thermal loads influence the natural frequencies evidently, especially the fundamental natural frequency. The order of mode shapes stays the same. Dynamic response peaks float to lower frequency range with the increment of structure temperature. Acoustic radiation efficiency of the plate subjected to thermal loads decreases in the mid-frequency band. For validation, numerical simulations are also carried out. It can be found that the combined approach of finite element method (FEM) and boundary element method (BEM) is more appropriate for radiation problems.

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Sato, Yuya, Yoshiaki Murakami, Igi Satoshi, and Nobuyuki Ishikawa. "Critical Conditions of Cold Cracking in High Strength Steel Weld Based on the Local Stress Distribution and Hydrogen Accumulation." Materials Science Forum 941 (December 2018): 153–57. http://dx.doi.org/10.4028/www.scientific.net/msf.941.153.

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In this study, the occurrence of cold cracking in high strength steel welds were investigated in terms of residual stress and hydrogen diffusion behavior. The y-groove weld cracking test of TS780MPa grade steel plate was conducted with intentionally introducing hydrogen into the shielding gas during the gas-metal arc welding (GMAW). Since local stress is one of the most important factors for the cold cracking, residual stress distribution in the weld joint was measured by the neutron diffraction using TAKUMI in J-PARC. The root region, which is usually the crack initiation site in the y-groove cold cracking test, was under a multi-axial stress state and showed highest tensile residual stress in the transverse direction. It was considered that hydrogen diffusion and accumulation could be enhanced in the high stressed root region, resulting in cold cracking. Therefore, hydrogen diffusion behavior and stress distribution in the y-groove weld joint was investigated by a coupled thermo elastic plastic and hydrogen diffusion analyses. Hydrogen accumulation occurred in the root region where showed highest hydrostatic stress. The point where showed the hydrogen accumulation was well corresponded to the crack initiation site. It was indicated that local hydrogen concentration after welding was another important key factor for the cold cracking. From these investigations, it was essential to take the combination of local hydrogen concentration and residual stress distribution near the root region into account for the highly precise estimation of cold cracking.

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Semerak, M., N. Ferents, D. Kharyshyn, and S. Vovk. "MATHEMATICAL MODELING OF STRENGTH-DEFORMED CONDITION OF PIPE CONCRETE CONSTRUCTIONS AT SUSTAINABLE TEMPERATURE." Fire Safety 35 (February 26, 2020): 63–68. http://dx.doi.org/10.32447/20786662.35.2019.10.

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The mathematical modeling of the thermo-stressed state of pipe-concrete structures under conditions of stationary thermal conductivity is carried out. During the study, the most common structural type of TBC was selected and mathematical models of the stress-strain state of TBA under heating conditions were taken into account, taking into account their geometric dimensions and thermophysical characteristics of metal and concrete. The main feature of the TBC study is that the heat exchange in the structure, as well as the corresponding force response, are investigated independently of each other, whereas the problem of fire resistance should be posed as a classical problem of elasticity, taking into account the mutual influence of temperature and mechanical stresses. In two-layer structures (concrete - metal), the largest radial stresses that occur in concrete work in tension. Tensile stresses occur in the thickness of the outer tube. The stresses occurring on the inner surface of the steel sleeve coincide with the stresses in the concrete. When approaching the outer surface, they decrease and on the surface r = R2 equal to zero. In the case where the coefficients of linear extension αt (i = 1, 2) are equal to each other, the maximum tensile stresses are reduced within 0≤r≤R1 .; if νi (i = 1, 2) within 0≤ r≤R2, the stresses will also decrease. Axial stresses work on compression. They reach maximum value in the outer shell. For equal values αt (1) = αt (2), the magnitude of the stresses does not change, and at ν1 = ν2 the stresses in the metal will decrease. Ring stresses in the region 0≤ r≤R1 are tensile stresses and in the region R1≤ r≤R2 are compression stresses, and the compression stresses are greater than the tensile stresses in concrete. For αt (1) = αt (2), the stresses in the concrete decrease and for ν1 = ν2.

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Ukrayinets, Nataliia, Olena Murahovska, and Olha Prokhorova. "Solving a one mixed problem in elasticity theory for half-space with a cylindrical cavity by the generalized Fourier method." Eastern-European Journal of Enterprise Technologies 2, no. 7 (110) (April 30, 2021): 48–57. http://dx.doi.org/10.15587/1729-4061.2021.229428.

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Designing and constructing underground structures for various purposes, such as tunnels, mines, mine workings, necessitate the development of procedures for calculating their strength and reliability. The physical model of such objects worth considering is a homogeneous isotropic half-space that contains an infinitely long hollow cylinder, located parallel to its border. One can explore problems related to the mechanics of deformable solids for such a multiply connected body. This paper reports the proofs of addition theorems for the basic solutions to the Lamé equation regarding the half-space and cylinder recorded, respectively, in the Cartesian and cylindrical coordinate systems. This result is important from a theoretical point of view in order to substantiate a numerical-analytical method ‒ the generalized Fourier method. This method makes it possible to solve spatial boundary problems from the theory of elasticity and thermo-elasticity for isotropic and transversal-isotropic multiply connected bodies. Similar to the classical Fourier method, the general solutions to equilibrium equations have been used here but in several coordinate systems rather than one. From a practical point of view, this method has made it possible to investigate the combined problem of elasticity theory regarding the multiply-connected body described above. The analysis of the stressed-strained state of this elastic body has made it possible to draw conclusions on determining those regions that are most vulnerable to destruction. The highest values are accepted by normal stresses in the region between the boundaries of the half-space and the cylinder. Changing the σy component along the Ox axis corresponds to the displacements assigned on the half-space. The τxy component contributes less to the distribution of stresses than σx and σy. The applied aspect of using the reported results is the possibility to apply them when designing underground structures

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Kudaykulov, Anarbay, Erkin Arinov, Nurlybek Ispulov, Abdul Qadir, and Kalamkas Begaliyeva. "Numerical Study of a Thermally Stressed State of a Rod." Advances in Mathematical Physics 2019 (June 2, 2019): 1–9. http://dx.doi.org/10.1155/2019/8986010.

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This paper considers a new method based on the law of energy conservation for the study of thermo-stress-strain state of a rod of limited length with simultaneous presence of local heat fluxes, heat exchanges, and thermal insulation. The method allows determining the field of temperature distribution and the three components of deformations and stresses, as well as the magnitude of the rod elongation and the resulting axial force with an accuracy of satisfying the energy conservation laws. For specific initial data, all the sought-for ones are determined numerically with high accuracy. We found that all solutions satisfy the laws of energy conservation.

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Nedaivozov, A. V., and V. N. Afanasiev. "Experimental Investigation of the Operation Modes of a Flat Loop Heat Pipe." Mechanical Engineering and Computer Science, no. 1 (March 1, 2019): 1–12. http://dx.doi.org/10.24108/0119.0001448.

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The paper presents the experimentally investigated operation modes of a flat loop heat pipe (LHP). The LHP is an efficient heat transfer device operating on the principle of evaporation-condensation cycle and successfully applied in space technology, including cooling heat-stressed components of electronic devices and computer equipment.We have experimentally studied how design parameters of the vapor line and its coolant flow influence on the LHP operation mode and also have determined the causes for emerging oscillatory mode of the LHP operation at low heat load. The paper depicts the experimentally measured temperatures in the LHP characteristic points and the photographs of the coolant flow in the vapor line.Based on the experimental data, we have drawn the following conclusions:A vapor-liquid coolant flow in the vapor line in the range of the heat loads under consideration has been detected. There is no superheating vapour observed.The flow regime of the vapor-liquid mixture depends on both the heat load and the vapor pipe diameter. The decrease in the internal diameter of the investigated vapor line section from 7 mm to 4 mm led to the increase of its vapor content and to the decrease of the heating surface temperature when the heat loads were above 80 W. For example, the temperature of the heating surface T1 decreased from 109.5 °С to 100 °С at a heat load of 110 W. Reducing the heat load from 80 W to 60 W leads to a change in the flow regime of the vapor-water mixture from the annular to the slug regime. Found that at low heat loads (up to 40 W), there is no LHP loop operation observed. Periodic fluctuations in the water level in the vapor line are detected. The LHP operates in thermo-syphon mode. For these heat loads, the influence of the vapor line diameter on the thermal state of the LHP is not observed.Found that at low heat loads the LHP operation mode depends only on the flow regime of the coolant in the vapor line. With the annular regime of the coolant flow in the vapor line, a stationary mode of operation of the LHP is observed. When changing the flow regime of the coolant from the annular to the slug, the LHP operation mode is changed from stationary to oscillatory.

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Litovchenko, V. G., I. P. Lisovskyy, Cor Claeys, V. P. Kladko, S. O. Zlobin, M. V. Muravska, O. O. Efremov, and M. V. Slobodjan. "Effect of Grown-In Defects on the Structure of Oxygen Precipitates in Cz-Si Crystals with Different Diameter." Solid State Phenomena 131-133 (October 2007): 405–12. http://dx.doi.org/10.4028/www.scientific.net/ssp.131-133.405.

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IR-spectroscopy with computer analysis of the shape of the Si-O absorption band, electron microscopy, X-rays diffraction and measurements of unsteady photoconductivity timedecay under band-to band excitation were used to investigate the influence of defects in different diameter (40 – 300 mm) Si ingots on the oxygen precipitation due to two-stage annealing (750 оС + 1050 оС). It is shown that large size Cz-Si ingots have a relatively low concentration of electrically active micro-defects, containing small (0.06 – 0.1 μm) dislocation loops. During thermal treatments this leads to the formation of a low stressed oxide phase (SiO2) with an enhanced thermo-stability. The precipitates in small size ingots, however, contain distorted 4-fold rings of SiO4 tetrahedra.

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Sahabutdinova, Ljajsan, Oleg Smetannikov, and Gleb Ilyinykh. "DEVELOPMENT OF AN INTEGRATED METHOD OF CALCULATION OF THE STRESSED-DEFORMED STATE OF THE COMPOSITION SHELL IN THE PROCESS OF MANUFACTURE." Applied Mathematics and Control Sciences, no. 3 (September 30, 2019): 84–99. http://dx.doi.org/10.15593/2499-9873/2019.3.05.

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The paper discusses the key stages of developing an integrated methodology for predicting the stress-strain state of a sand-polymer mandrel-plastic shell system during heat treatment with the adaptation of experimentally determined viscoelastic characteristics of components in the CAE ANSYS Mechanical APDL package. The first stage solves the problem of determining the effective viscoelastic characteristics for the shell. Viscoelastic characteristics are determined on the basis of the developed complex experimental calculation method based on the solution of boundary quasistatic problems of thermomechanics on a representative volume at two scale levels. The results obtained in this work, based on experimental data and developed numerical methods for determining the thermo-viscoelastic characteristics of composites, make it possible to estimate the contribution of stress relaxation in the mandrel and the shell to the evolution of the stress-strain state in the process of manufacturing the shell. Also, the developed technique makes it possible to predict the appearance of technological defects and determine the stages of heat treatment at which these defects occur.

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Dwivedi, Sharad K., Sahana Basu, Santosh Kumar, Surbhi Kumari, Alok Kumar, Sneha Jha, Janki S. Mishra, Bhagwati P. Bhatt, and Gautam Kumar. "Enhanced antioxidant enzyme activities in developing anther contributes to heat stress alleviation and sustains grain yield in wheat." Functional Plant Biology 46, no. 12 (2019): 1090. http://dx.doi.org/10.1071/fp19016.

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Climatic variations along with a rise in temperature during the winter season impose severe heat stress during the anthesis stage of spring wheat, resulting in severe yield losses. The present study was conducted to evaluate the influence of heat stress on redox homeostasis in developing anthers and flag leaves of wheat. Five Indian bread wheat genotypes were studied under field conditions during the dry season, with two extreme sowing dates (timely and very late sown) to explore the effect of heat stress on anthesis stage. Results showed that elevated temperature during anthesis caused significant increase in reactive oxygen species (ROS) content and malondialdehyde (MDA) accumulation in developing anthers, triggering pollen mortality. Moreover, defective source (leaf) to the sink (anthers) mobilisation of starch also contributes in reducing pollen viability. However, ROS-induced oxidative damage of developing anthers under heat stress varied among the wheat genotypes depending upon differential antioxidant enzyme activities. Wheat genotype with enhanced antioxidant activities and reduced ROS built up in developing anthers sustained their grain yield, suggesting thermo-tolerance in wheat to be associated with antioxidant enzyme-mediated improved ROS-scavenging mechanism not only in leaves even in developing anther also. In the present study, heat stressed wheat genotype WH 730 exhibited effective source to sink mobilisation and sustainable grain yield with improved ROS scavenging, conferring greater potential for heat tolerance. We conclude that redox homeostasis and balanced source sink activity played a significant role for sustainable yield and heat tolerance in wheat.

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Zarubin, V. S., V. N. Zimin, A. N. Kuvyrkin, and I. Yu Savel’eva. "Thermo-Stressed State of a Hollow Polymer Dielectric Cylinder." Journal of Engineering Physics and Thermophysics, August 28, 2021. http://dx.doi.org/10.1007/s10891-021-02383-w.

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Александров, А. А., В. С. Зарубин, and В. Н. Зимин. "Thermo-Stressed State of the Shell of a Cylindrical Cryogenic Tank when it is Being Filled." Proceedings of Higher Educational Institutions. Маchine Building, no. 112 (April 2016). http://dx.doi.org/10.18698/0536-1044-2016-4-5-15.

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Wassing, B. B. T., T. Candela, S. Osinga, E. Peters, L. Buijze, P. A. Fokker, and J. D. Van Wees. "Time-dependent Seismic Footprint of Thermal Loading for Geothermal Activities in Fractured Carbonate Reservoirs." Frontiers in Earth Science 9 (September 14, 2021). http://dx.doi.org/10.3389/feart.2021.685841.

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This paper describes and deploys a workflow to assess the evolution of seismicity associated to injection of cold fluids close to a fault. We employ a coupled numerical thermo-hydro-mechanical simulator to simulate the evolution of pressures, temperatures and stress on the fault. Adopting rate-and-state seismicity theory we assess induced seismicity rates from stressing rates at the fault. Seismicity rates are then used to derive the time-dependent frequency-magnitude distribution of seismic events. We model the seismic response of a fault in a highly fractured and a sparsely fractured carbonate reservoir. Injection of fluids into the reservoir causes cooling of the reservoir, thermal compaction and thermal stresses. The evolution of seismicity during injection is non-stationary: we observe an ongoing increase of the fault area that is critically stressed as the cooling front propagates from the injection well into the reservoir. During later stages, models show the development of an aseismic area surrounded by an expanding ring of high seismicity rates at the edge of the cooling zone. This ring can be related to the “passage” of the cooling front. We show the seismic response of the fault, in terms of the timing of elevated seismicity and seismic moment release, depends on the fracture density, as it affects the temperature decrease in the rock volume and thermo-elastic stress change on the fault. The dense fracture network results in a steeper thermal front which promotes stress arching, and leads to locally and temporarily high Coulomb stressing and seismicity rates. We derive frequency-magnitude distributions and seismic moment release for a low-stress subsurface and a tectonically active area with initially critically stressed faults. The evolution of seismicity in the low-stress environment depends on the dimensions of the fault area that is perturbed by the stress changes. The probability of larger earthquakes and the associated seismic risk are thus reduced in low-stress environments. For both stress environments, the total seismic moment release is largest for the densely spaced fracture network. Also, it occurs at an earlier stage of the injection period: the release is more gradually spread in time and space for the widely spaced fracture network.

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Gracheva, Lyudmila Ivanovna. "Predicting performance of a thermal shield of a spacecraft in a high-temperature gas flow." Journal of Mechanical Engineering Research 2, no. 1 (June 28, 2019). http://dx.doi.org/10.30564/jmer.v2i1.763.

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A fundamental understanding of the mechanism of material interaction with a medium is based on correspondence between experimental studies and actual operating conditions of a given model or a structure. We estimated performance of thermal shield structures based on computations brought about considering physical properties of materials obtained under conditions simulating re-entry of a spacecraft into the atmosphere.A thermal shield is considered of a layered type shell, made of fiber glass with phenol-phormaldehide matrix. Both elastic and thermo-physical characteristics are varied depending on the temperature change.A thermal-stressed state of a cylindrical shield subjected to action of a high-temperature gas flow, is defined based on solving a 3D problem simultaneously using equations of theory of elasticity, thermal conductivity, and numerical analysis. Results are given as dependencies of stress distributions through the thermal coating, taking into account such parameters of atmosphere in re-entry as temperature, heating rate, pressure of a gaseous medium.

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Hoshi, Daisuke, Isao Nakamura, and Masao Isomura. "Poly-crystalline Ge thin films prepared by RF sputtering method for thermo photo voltaic application." MRS Proceedings 862 (2005). http://dx.doi.org/10.1557/proc-862-a6.5.

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AbstractThe poly crystalline Ge films were prepared by the RF sputtering method with Ar and Ar-H2 mixture gases. The crystallization temperature increases from 400 °C to 500 °C due to the H2 introduction into the sputtering gases. On the other hand, the H2 introduction decreases the absorption coefficients in the long wavelength region corresponding to lower energy values than the energy gap of Ge, although much higher absorption coefficients are observed in the case of the Ar sputtering. Probably, the gap state density decreases due to the hydrogen termination of dangling-bonds in the grain-boundaries. The (220) preferential orientation is stressed and the highest Hall mobility is obtained with 75% of the gas flow ratio [Ar/ (Ar+H2)]. The preferential growth probably causes higher quality Ge films.

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Abd Elbar, Ola H., Amr Elkelish, Gniewko Niedbała, Reham Farag, Tomasz Wojciechowski, Soumya Mukherjee, Ayman F. Abou-Hadid, et al. "Protective Effect of γ-Aminobutyric Acid Against Chilling Stress During Reproductive Stage in Tomato Plants Through Modulation of Sugar Metabolism, Chloroplast Integrity, and Antioxidative Defense Systems." Frontiers in Plant Science 12 (October 18, 2021). http://dx.doi.org/10.3389/fpls.2021.663750.

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Despite the role of γ-aminobutyric acid (GABA) in plant tolerance to chilling stress having been widely discussed in the seedling stage, very little information is clear regarding its implication in chilling tolerance during the reproductive stage of the plant. Here, we investigated the influence of GABA (1 and 2mM) as a foliar application on tomato plants (Solanum lycopersicum L. cv. Super Marmande) subjected to chilling stress (5°C for 6h/day) for 5 successive days during the flowering stage. The results indicated that applied GABA differentially influenced leaf pigment composition by decreasing the chlorophyll a/b ratio and increasing the anthocyanin relative to total chlorophyll. However, carotenoids were not affected in both GABA-treated and non-treated stressed plants. Root tissues significantly exhibited an increase in thermo-tolerance in GABA-treated plants. Furthermore, applied GABA substantially alleviated the chilling-induced oxidative damage by protecting cell membrane integrity and reducing malondialdehyde (MDA) and H2O2. This positive effect of GABA was associated with enhancing the activity of phenylalanine ammonia-lyase (PAL), catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX). Conversely, a downregulation of peroxidase (POX) and polyphenol oxidase (PPO) was observed under chilling stress which indicates its relevance in phenol metabolism. Interesting correlations were obtained between GABA-induced upregulation of sugar metabolism coinciding with altering secondary metabolism, activities of antioxidant enzymes, and maintaining the integrity of plastids’ ultrastructure Eventually, applied GABA especially at 2mM improved the fruit yield and could be recommended to mitigate the damage of chilling stress in tomato plants.

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Journal articles on the topic 'Thermo-stressed state'

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