Journal articles: 'Long-term thermal exposure'

1

Caron, Jeremy, and Lee Pike. "Weldability of HAYNES 282 superalloy after long-term thermal exposure." MATEC Web of Conferences 14 (2014): 13003. http://dx.doi.org/10.1051/matecconf/20141413003.

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Ning, Haoran, Zhaojun Wang, and Yuchen Ji. "Thermal history and adaptation: Does a long-term indoor thermal exposure impact human thermal adaptability?" Applied Energy 183 (December 2016): 22–30. http://dx.doi.org/10.1016/j.apenergy.2016.08.157.

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Okazaki, M., S. Shirai, and T. Uchiyama. "Effect of Long Term Thermal Exposure on Adhesion Strength of TBC." Proceedings of the JSME annual meeting 2003.1 (2003): 111–12. http://dx.doi.org/10.1299/jsmemecjo.2003.1.0_111.

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Srinivasan, V., N. S. Cheruvu, T. J. Carr, and C. M. O'rien. "Degradation of MCrAlY Coating and Substrate Superalloy During Long Term Thermal Exposure." Materials and Manufacturing Processes 10, no. 5 (September 1995): 955–69. http://dx.doi.org/10.1080/10426919508935082.

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Wang, Ting Ting, Chang Shuai Wang, Jian Ting Guo, and Lan Zhang Zhou. "Stability of Microstructure and Mechanical Properties of GH984G Alloy during Long-Term Thermal Exposure." Materials Science Forum 747-748 (February 2013): 647–53. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.647.

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A low cost Ni-Fe-based wrought superalloy for 700 advance ultra-supercritical coal-fired power plants was developed. The stability of microstructure and mechanical properties of this alloy during long-term thermal exposure was investigated by SEM,TEM and tensile tests. The experimental results showed that the major precipitates in the alloy were spherical γ, MC and discrete M23C6 distributing along grain boundary after the long-term exposure at 700 and 750 and no harmful phases, such as σ phase and η phase, were found. However, after exposure at 800 up to 3000 h, small amount of lath-like η phase precipitated at grain boundary by consuming the surrounding γ. The η phase exhibited a fixed orientation relationship with the γ matrix. During thermal exposure γ coarsened with increasing the exposure time and exposure temperature. In addition, all major phases and their stability temperature ranges were calculated by JMatPro and these results were confirmed by the experimental results. The 700 tensile tests revealed that the alloy after exposure at 700 and 750 for 3000 h exhibited excellent ductility and strength. Therefore, the GH984G alloy possessed excellent stability of microstructure and mechanical properties between 700 and 750 up to 3000 h, and it is a promising material for 700 advance ultra-supercritical coal-fired power plants.

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Chen, Zhiyuan, Zhengkun Cai, Xiaosong Jiang, Song Chen, Zewen Huang, and Hongliang Sun. "Microstructure Evolution of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y Alloy during Long-Term Thermal Exposure." Materials 13, no. 7 (April 2, 2020): 1638. http://dx.doi.org/10.3390/ma13071638.

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The hot-rolled alloy Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y was exposed to 700 °C air for up to 10,000 h. The changes in microstructure were observed using scanning and transmission electron microscopies. It was found that the α2 laths, α2 + γ lamellae, and B2(ω) structure of the alloy showed thermodynamic instability. There were three types of phase transformation in the alloy during long-term thermal exposure. The first was α2 → γ, which occurs in the interior and boundary of the α2 + γ lamellae. The second was α2 + γ → B2(ω), which occurs on the α2 + γ boundary. In addition, B2(ω) also precipitates on the γ/γ interfaces. The third was B2(ω) → γ, which describes the precipitation of micron-scale γ phases in the B2(ω) area after thermal exposure of 5000 h. The volume fraction and size of the B2(ω) area and equiaxed γ grains continued to increase throughout the exposure process. Large-sized γ grains and a B2 area of tens of microns appeared in the microstructure after long-term thermal exposure. The volume fractions of the B2 area and the equiaxed γ grains after thermal exposure of 10,000 h reached 16.8% and 63.2%, respectively.

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Han, G. W., and Y. Y. Zhang. "Variations in microstructure and properties of GH783 alloy after long term thermal exposure." Materials Science and Engineering: A 441, no. 1-2 (December 2006): 253–58. http://dx.doi.org/10.1016/j.msea.2006.08.092.

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Varghese, Paulson, Prabhat Kumar Shukla, E. Vetrivendan, Sanjay Kumar Das, D. Ponraju, and S. Ningshen. "Long-term exposure of MgAl2O4 and Y2O3 thermal barrier coatings in molten sodium." Surface and Coatings Technology 381 (January 2020): 125111. http://dx.doi.org/10.1016/j.surfcoat.2019.125111.

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Song, Erdong, Brian S. Swartzentruber, Chowdary R. Koripella, and Julio A. Martinez. "Highly Effective GeNi Alloy Contact Diffusion Barrier for BiSbTe Long-Term Thermal Exposure." ACS Omega 4, no. 5 (May 29, 2019): 9376–82. http://dx.doi.org/10.1021/acsomega.9b00551.

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Xiao, Xuan, Xu Le, Zeng Chao, Li Yuan Sheng, Yong An Guo, and Lan Zhang Zhou. "Carbide Evolution of a Directionally Solidified Ni-Based Superalloy during Long-Term Exposure." Advanced Materials Research 452-453 (January 2012): 72–76. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.72.

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Directionally solidified Ni-based superalloy DZ483 is a kind of potential material for the blade of an advanced heavy duty gas turbine, which has good combination properties. The carbide degradation behaviors of DZ483 alloy during long-term thermal exposures were investigated at different conditions in this paper. The results show that during the long-term exposure, primary carbide will decompose in the form of MC + γ → M23C6 + γ'. Carbide on the grain boundary could be decomposed more easily than intragranular carbide. With the increase of aging time, decomposition could be observed more obviously, carbides on the grain boundary become bigger and the morphology of carbide near the grain boundary tends to be more complex. The fine dispersive particles of M23C6 on the grain boundary will grow up gradually to a thin consecutive chain of carbide with the increase of aging time.

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Chung, Bongjin, Shin Sungchul, Jaeho Shim, and Seongwoo Ryu. "Mechanical Properties of Epoxy Adhesive Under Thermal Aging and Their Chemical Degradation Behavior." Journal of Nanoscience and Nanotechnology 21, no. 8 (August 1, 2021): 4444–49. http://dx.doi.org/10.1166/jnn.2021.19424.

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Epoxy adhesive was analyzed under long term thermal aging and mechanical properties and chemical degradation were observed by X-ray photoelectron spectroscopy (XPS). Long term thermal exposure of epoxy causes a noticeable reduction in adhesive properties. We developed a predictive model of temperature and time dependent aging. The temperature dependent aging behavior of epoxy adhesive shows good agreement with conventional Arrhenius equations. Using XPS analysis, we also discovered a correlation between chemical degradation and the adhesive properties. Decay of C–C bonding ratio induced chain-scission of epoxy adhesive; increase of total numbers of C–O and C═O induced oxidation of epoxy adhesive during thermal exposure.

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Han, F. F., B. M. Zhou, H. F. Huang, B. Leng, Y. L. Lu, Z. J. Li, and X. T. Zhou. "Effect of long-term thermal exposure on the hot ductility behavior of GH3535 alloy." Materials Science and Engineering: A 673 (September 2016): 299–306. http://dx.doi.org/10.1016/j.msea.2016.07.034.

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13

Kimmig, S., S. Elgeti, and Jeong-Ha You. "Impact of long-term thermal exposure on a SiC fiber-reinforced copper matrix composite." Journal of Nuclear Materials 443, no. 1-3 (November 2013): 386–92. http://dx.doi.org/10.1016/j.jnucmat.2013.07.055.

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14

Huang, Ming, Xinye Yang, Weiwei Liu, Jiarong Li, Sen Yang, and Yuan Qin. "Precipitation characteristics of a nickel-based single-crystal superalloy after long-term thermal exposure." International Journal of Materials Research 109, no. 9 (September 14, 2018): 811–18. http://dx.doi.org/10.3139/146.111671.

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15

Zhong, Zhi Hong, Yue Feng Gu, Yong Yuan, Zhan Shi, and Yu Cheng Wu. "Influence of Thermal Exposure on the Microstructure, Surface Stability and Strength of a New Fe-Ni-Base Superalloy for A-USC Applications." Materials Science Forum 816 (April 2015): 523–28. http://dx.doi.org/10.4028/www.scientific.net/msf.816.523.

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A low-cost, high-creep strength wrought Fe‒Ni-base superalloy for 700 °C advanced ultra-supercritical coal-fired power plant applications has been developed. The microstructural stability of this alloy during long-term exposures at 700 °C‒750 °C for up to 10000 h was investigated by SEM and TEM. The correlation between the microstructure evolution and the mechanical properties was studied. The experimental results showed that the major precipitates in the alloy were spherical γ′, MC and discrete M23C6 after the long-term exposure at 700 °C and 750 °C and no harmful phases, such as σ phase and η phase, were observed. The amount of M23C6 increased with exposure time at 700 °C while it decreased at 750 °C. During thermal exposure γ′ coarsened with increasing the exposure time and exposure temperature. Alloy showed good oxidation resistance due to the formation of external layer of Cr2O3. The yield strength of the alloy increased at first and then decreased with increasing exposure time at 700 °C, but it decreased gradually with increasing exposure time at 750 °C. The relationship between yield strength and the dominant deformation mechanisms of the alloy was discussed.

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Tan, Mei Lin, Chang Shuai Wang, Yong An Guo, Gu Song Li, Jian Ting Guo, and Lan Zhang Zhou. "Thermal Stability and Tensile Properties of GH984G Alloy for A-USC Power Plants." Materials Science Forum 816 (April 2015): 534–39. http://dx.doi.org/10.4028/www.scientific.net/msf.816.534.

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GH984G is a new Ni-Fe-based alloy which has been designed for use as superheater, reheater, and header materials for boilers in 700°C advanced ultra-supercritical (A-USC) coal-fired power plants. In this paper, the tensile properties and microstructure evolutions of GH984G were investigated during long-term thermal exposure at 700 and 750°C up to 15000h. The results show that the major precipitates were MC, M23C6 and γ ́, and no detrimental TCP or GCP phase appeared during long-term thermal exposure. The morphology of γ ́ was spherical and had no obvious change, but the size increases. After thermal exposure at 700°C for 15000h, the 700°C yield strength slightly increased, but the yield strength decreased after thermal exposure at 750°C for 15000h. The variation of strength is attributed to the coarsening of γ ́ precipitation. The deformation mechanism is the moving dislocations shear γ ́ precipitates and the stacking faults form in γ ́ precipitates at room temperature and 700°C. At 750°C, the deformation mechanism is characterized by the formation of dislocation loops and tangles.

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17

Jia, Yu Xian. "The Microstructure Evolution of a Nickel-Base Single Crystal Superalloy after Long-Term Aging." Advanced Materials Research 1088 (February 2015): 217–20. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.217.

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Microstructure evolution of a nickel-base single crystal superalloy during thermal exposure at 982°C was investigated. The SEM studies revealed that the size of γ' phase increased and some of which linked together with the elongation of the exposure time. There is acicular phase precipitation after the long-term ageing treatment. The TCP phase is not increased by the increment of ageing time after reaching a certain amount. There are skeleton shape carbides precipitate after 100h and 300h. The amount of precipitated carbides decreases by the elongation of ageing time.

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18

Liu, T., J. S. Dong, L. Wang, Z. J. Li, X. T. Zhou, L. H. Lou, and J. Zhang. "Effect of Long-term Thermal Exposure on Microstructure and Stress Rupture Properties of GH3535 Superalloy." Journal of Materials Science & Technology 31, no. 3 (March 2015): 269–79. http://dx.doi.org/10.1016/j.jmst.2014.07.021.

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19

Cloyed, Carl S., Anthony I. Dell, Tracie Hayes, Rebecca L. Kordas, and Eoin J. O'Gorman. "Long‐term exposure to higher temperature increases the thermal sensitivity of grazer metabolism and movement." Journal of Animal Ecology 88, no. 6 (April 2019): 833–44. http://dx.doi.org/10.1111/1365-2656.12976.

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Nair, B. G., J. P. Singh, and M. Grimsditch. "Stress analysis in thermal barrier coatings subjected to long-term exposure in simulated turbine conditions." Journal of Materials Science 39, no. 6 (March 2004): 2043–51. http://dx.doi.org/10.1023/b:jmsc.0000017767.36955.5c.

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21

Almeida, Renato S. M., Eduardo L. Bergmüller, Hanna Lührs, Michael Wendschuh, Bernd Clauß, Kamen Tushtev, and Kurosch Rezwan. "Thermal exposure effects on the long-term behavior of a mullite fiber at high temperature." Journal of the American Ceramic Society 100, no. 9 (May 5, 2017): 4101–9. http://dx.doi.org/10.1111/jace.14922.

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22

Zhou, Dingmao, Xianjue Ye, Jianwei Teng, Chao Li, and Yunping Li. "Effect of Nb on Microstructure and Mechanical Property of Novel Powder Metallurgy Superalloys during Long-Term Thermal Exposure." Materials 14, no. 3 (January 31, 2021): 656. http://dx.doi.org/10.3390/ma14030656.

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Microstructure and mechanical properties of novel Ni-20Co-12Cr superalloys, with and without Nb addition, were systematically studied during long-term thermal exposure. With increased exposure time, the average diameter of the γ′ precipitates increased in both alloys in succession; this is more obviously observed in alloy containing 1 wt% Nb (1Nb). It is suggested that Nb increased the γ′ coarsening rate by accelerating the diffusion of Al and Nb in γ matrix. In addition, the γ′ phase fraction is increased by about 4% in 1Nb compared to the alloy without Nb (0Nb). The morphology of the γ′ phase changed from near-spherical to cuboidal shape during exposure in both alloys. Due to the increased γ/γ′ lattice misfit by Nb addition, 1Nb alloy showed an earlier tendency of shape change. Vickers hardness results revealed that the overall hardness decreased with the exposure time because the size increment of the γ′ precipitate weakened the precipitates strengthening and Orowan strengthening.

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Yun, Hyunjun, Jinho Yang, Byong Hyoek Lee, Jongcheol Kim, and Jong-Ryeul Sohn. "Indoor Thermal Environment Long-Term Data Analytics Using IoT Devices in Korean Apartments: A Case Study." International Journal of Environmental Research and Public Health 17, no. 19 (October 8, 2020): 7334. http://dx.doi.org/10.3390/ijerph17197334.

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IoT-based monitoring devices can transmit real-time and long-term thermal environment data, enabling innovative conversion for the evaluation and management of the indoor thermal environment. However, long-term indoor thermal measurements using IoT-based devices to investigate health effects have rarely been conducted. Using apartments in Seoul as a case study, we conducted long-term monitoring of thermal environmental using IoT-based real-time wireless sensors. We measured the temperature, relative humidity (RH), and CO2 in the kitchen, living room, and bedrooms of each household over one year. In addition, in one of the houses, velocity and globe temperatures were measured for multiple summer and autumn seasons. Results of our present study indicated that outdoor temperature is an important influencing factor of indoor thermal environment and indoor RH is a good indicator of residents’ lifestyle. Our findings highlighted the need for temperature management in summer, RH management in winter, and kitchen thermal environment management during summer and tropical nights. This study suggested that IoT devices are a potential approach for evaluating personal exposure to indoor thermal environmental risks. In addition, long-term monitoring and analysis is an efficient approach for analyzing complex indoor thermal environments and is a viable method for application in healthcare.

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Xiao, Xuan, Xu Le, Zeng Chao, Li Yuan Sheng, Yong An Guo, and Lan Zhang Zhou. "Microstructure and Mechanical Property of a Directional Ni-Based Superalloy during Long-Term Exposure." Advanced Materials Research 452-453 (January 2012): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.51.

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Directional Ni-based superalloy DZ483 is an advanced gas turbine blade material for heavy duty gas turbine application, which has good combination properties. The major research of this paper is studied on DZ483 alloy’s microstructural changes and mechanical property during long-term exposures in service environments. The results showed that: During thermal processing, the size and distribution of γ' phase tends to be more homogeneous in the interdendritic spaces; the γ' phase on the dendrite seem to arrange in designated directions. During long-term exposures, the amount of the γ' phase was decreasing and the foursquare γ' phases gradually became abnormal with the increasing temperature. However, tensile properties of DZ483 have not decreased obviously

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Vecsei, Zsuzsanna, György Thuróczy, and István Hernádi. "The Effect of a Single 30-Min Long Term Evolution Mobile Phone-Like Exposure on Thermal Pain Threshold of Young Healthy Volunteers." International Journal of Environmental Research and Public Health 15, no. 9 (August 27, 2018): 1849. http://dx.doi.org/10.3390/ijerph15091849.

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Although the majority of mobile phone (MP) users do not attribute adverse effects on health or well-being to MP-emitted radiofrequency (RF) electromagnetic fields (EMFs), the exponential increase in the number of RF devices necessitates continuing research aimed at the objective investigation of such concerns. Here we investigated the effects of acute exposure from Long Term Evolution (LTE) MP EMFs on thermal pain threshold in healthy young adults. We use a protocol that was validated in a previous study in a capsaicin-induced hyperalgesia model and was also successfully used to show that exposure from an RF source mimicking a Universal Mobile Telecommunications System (UMTS) MP led to mildly stronger desensitization to repeated noxious thermal stimulation relative to the sham condition. Using the same experimental design, we did not find any effects of LTE exposure on thermal pain threshold. The present results, contrary to previous evidence obtained with the UMTS modulation, are likely to originate from placebo/nocebo effects and are unrelated to the brief acute LTE EMF exposure itself. The fact that this is dissimilar to our previous results on UMTS exposure implies that RF modulations might differentially affect pain perception and points to the necessity of further research on the topic.

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Zhu, C. Z., Y. Yuan, J. M. Bai, P. Zhang, J. B. Yan, C. Y. You, and Y. F. Gu. "Impact toughness of a modified HR3C austenitic steel after long-term thermal exposure at 650 °C." Materials Science and Engineering: A 740-741 (January 2019): 71–81. http://dx.doi.org/10.1016/j.msea.2018.10.084.

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27

Zeng, Qiang, Ping Yan, Jing Chen Zhao, Long Fei Zhang, and Lian Li. "Coarsening Behavior of Precipitates in a Conventional Cast Nickel Base Superalloy during Long Term Thermal Exposure." Materials Science Forum 788 (April 2014): 452–58. http://dx.doi.org/10.4028/www.scientific.net/msf.788.452.

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A long term aging treatment at 900oC for 3000h was carried out on a conventional cast nickel base superalloy with standard solution and aging treatment. The microstructural evolution including the phases within grains and at grain boundaries (GBs) during thermal exposure in the alloy was observed using OM and SEM. It was shown that the major phases in the alloy after standard heat treatment were γ' precipitates and coarse blocky MC carbides, both of which were distributed not only within grains but also at GBs. During aging, the size of MC carbides and γ' precipitates both within grains and at GBs increased with increasing aging time. It was found that two characteristics of MC carbide and γ' precipitates evolved with aging time: the one is that the coarsening ratio of carbides and γ' precipitates at GBs were significantly higher than that of carbide and γ' precipitates inside the grains; the other is that the coarsening ratio of carbides was markedly higher than that of γ' precipitates. M6C carbide and η phase initially formed in the edge of MC carbide at the expense of MC carbides and γ' precipitates in the vicinity of MC during the early stage of aging. After 3000h, MC carbides inside the grains were covered by η phase films, while those distributed at GBs were completely decomposed into η phase and M6C particles.

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Gao, Shuang, Jieshan Hou, Yongan Guo, and Lanzhang Zhou. "Microstructural evolution and mechanical properties of solution annealed cast IN617B alloy during long-term thermal exposure." Materials Science and Engineering: A 704 (September 2017): 302–10. http://dx.doi.org/10.1016/j.msea.2017.08.011.

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Qin, X. Z., J. T. Guo, C. Yuan, J. S. Hou, L. Z. Zhou, and H. Q. Ye. "Long-term thermal exposure responses of the microstructure and properties of a cast Ni-base superalloy." Materials Science and Engineering: A 543 (May 2012): 121–28. http://dx.doi.org/10.1016/j.msea.2012.02.059.

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Oleru, George, and S. A. Ademiluyi. "Some acute and long-term effects of exposure in welding and thermal-cutting operations in Nigeria." International Archives of Occupational and Environmental Health 59, no. 6 (September 1987): 605–12. http://dx.doi.org/10.1007/bf00377922.

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31

Tan, Zihao, Lin Yang, Xinguang Wang, Yunling Du, Lihua Ye, Guichen Hou, Yanhong Yang, et al. "Evolution of TCP Phase During Long Term Thermal Exposure in Several Re-Containing Single Crystal Superalloys." Acta Metallurgica Sinica (English Letters) 33, no. 5 (December 17, 2019): 731–40. http://dx.doi.org/10.1007/s40195-019-00976-2.

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Liu, Gang, Xueshan Xiao, Muriel Véron, and Soran Birosca. "The nucleation and growth of η phase in nickel-based superalloy during long-term thermal exposure." Acta Materialia 185 (February 2020): 493–506. http://dx.doi.org/10.1016/j.actamat.2019.12.038.

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Chen, Xiaofei, Zhihao Yao, Jianxin Dong, Hongwei Shen, and Yu Wang. "The effect of stress on primary MC carbides degeneration of Waspaloy during long term thermal exposure." Journal of Alloys and Compounds 735 (February 2018): 928–37. http://dx.doi.org/10.1016/j.jallcom.2017.11.166.

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Wang, Xu-dong, Zhong Yang, Qiang Gao, and Li-rong Liu. "Effect of long-term thermal exposure on microstructure and creep properties of DD5 single crystal superalloy." China Foundry 18, no. 3 (May 2021): 185–91. http://dx.doi.org/10.1007/s41230-021-9010-8.

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Valentin, Clever Aparecido, Marcelo Kobelnik, Yara Barbosa Franco, Fernando Luiz Lavoie, Jefferson Lins da Silva, and Marta Pereira da Luz. "Study of the Ultraviolet Effect and Thermal Analysis on Polypropylene Nonwoven Geotextile." Materials 14, no. 5 (February 26, 2021): 1080. http://dx.doi.org/10.3390/ma14051080.

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The use of polymeric materials such as geosynthetics in infrastructure works has been increasing over the last decades, as they bring down costs and provide long-term benefits. However, the aging of polymers raises the question of its long-term durability and for this reason researchers have been studying a sort of techniques to search for the required renewal time. This paper examined a commercial polypropylene (PP) nonwoven geotextile before and after 500 h and 1000 h exposure to ultraviolet (UV) light by performing laboratory accelerated ultraviolet-aging tests. The state of the polymeric material after UV exposure was studied through a wide set of tests, including mechanical and physical tests and thermoanalytical tests and scanning electron microscopy analysis. The calorimetric evaluations (DSC) showed distinct behaviors in sample melting points, attributed to the UV radiation effect on the aged samples. Furthermore, after exposure, the samples presented low thermal stability in the thermomechanical analysis (TMA), with a continuing decrease in their thicknesses. The tensile tests showed an increase in material stiffness after exposition. This study demonstrates that UV aging has effects on the properties of the polypropylene polymer.

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Petzová, Jana, Martin Březina, Miloš Baľák, Mária Dománková, and Ľudovít Kupča. "Application of Metallographic Methods for Thermal Ageing Evaluation on Samples from Primary Piping of NPP." Materials Science Forum 891 (March 2017): 60–66. http://dx.doi.org/10.4028/www.scientific.net/msf.891.60.

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During a long-term operation of nuclear power plants (NPP), the changes of structural material properties occur. To ensure the safe and reliable operation, it is necessary to monitor and evaluate these changes mainly on components from primary circuit of NPPs. One of the dominant ageing mechanisms of NPP components besides the radiation embrittlement and the fatigue loads is the thermal ageing. The thermal ageing is the temperature, material and time dependent degradation mechanisms due to long-term exposure at the operating temperature of 570 K.This paper describes the project for thermal ageing monitoring at primary piping in NPP Bohunice Unit 3. There are summarized the results obtained from evaluation of original primary piping material.

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Zhang, Tianyu, Teng Zhang, Yuting He, Sheng Zhang, Binlin Ma, and Zhigang Gao. "Long-Term Atmospheric Aging and Corrosion of Epoxy Primer-Coated Aluminum Alloy in Coastal Environments." Coatings 11, no. 2 (February 17, 2021): 237. http://dx.doi.org/10.3390/coatings11020237.

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Aircraft are subjected to extreme weather conditions in coastal areas. This study reports long-term atmospheric exposure tests carried out on an epoxy primer-coated aluminum alloy in a coastal environment for 7, 12, and 20 years. The micromorphology and characteristics of the section and surface, the products of corrosion, electrochemical impedance, and molecular structure of the coated specimens were examined through a spectrophotometer, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectrometer (XPS). The results showed that the angles of contact of the specimens with different numbers of years of atmospheric exposure satisfied the normal distribution. Their fractal dimensions increased with an increase in the duration of exposure. Intergranular corrosion and exfoliation corrosion appeared in the specimens after 20 years, where the product of corrosion was Al(OH)3. The impedances and thermal properties of the epoxy coatings were influenced by the synergistic effects of aging and post-curing. The impedances of the coatings decreased greatly after long-term atmospheric exposure. After 20 years of corrosion, the specimen showed the characteristics of the substrate being corroded. The mechanism of corrosion and the electrochemical equivalent circuit were also analyzed.

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Barker, Simon, K. V. Vassilevski, I. P. Nikitina, Nicolas G. Wright, and A. B. Horsfall. "Thermal Stress Response of Silicon Carbide pin Diodes Used as Photovoltaic Devices." Materials Science Forum 717-720 (May 2012): 997–1000. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.997.

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Recent progress in the field of silicon carbide sensor technology, such as wireless communications and sensors, has demonstrated the need for a resilient energy supply as an alternative to conventional batteries. Previous work has shown that silicon carbide is an effective energy harvester of UV light in high temperature and hostile environments. Until now however, there has been little work undertaken to assess the long-term effects of elevated temperature on such devices. Although it is understood that silicon carbide is unaffected by long-term temperature exposure below 400 °C, there has been little research into the overall device response and how changes in contact metallisation affect the photovoltaic behaviour.

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QIN, Xuezhi, Jianting GUO, Chao YUAN, Jieshan HOU, Lanzhang ZHOU, and Hengqiang YE. "EVOLUTIONS OF MICROSTRUCTURES AND MECHANICAL PROPERTIES OF TWO CAST Ni--BASED SUPERALLOYS DURING LONG--TERM THERMAL EXPOSURE." ACTA METALLURGICA SINICA 2010, no. 2 (March 3, 2010): 213–20. http://dx.doi.org/10.3724/sp.j.1037.2009.00449.

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Wu, Yunsheng, Xuezhi Qin, Changshuai Wang, and Lanzhang Zhou. "Microstructural evolution and its influence on the impact toughness of GH984G alloy during long-term thermal exposure." Journal of Materials Science & Technology 60 (January 2021): 61–69. http://dx.doi.org/10.1016/j.jmst.2020.06.005.

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Yang, Y. H., J. J. Yu, X. F. Sun, T. Jin, H. R. Guan, and Z. Q. Hu. "The influence of long-term thermal exposure on intermediate temperature brittleness behavior of a Nickel-base superalloy." Materials Characterization 66 (April 2012): 30–37. http://dx.doi.org/10.1016/j.matchar.2012.02.004.

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Goerler, J. V., I. Lopez-Galilea, L. Mujica Roncery, O. Shchyglo, W. Theisen, and I. Steinbach. "Topological phase inversion after long-term thermal exposure of nickel-base superalloys: Experiment and phase-field simulation." Acta Materialia 124 (February 2017): 151–58. http://dx.doi.org/10.1016/j.actamat.2016.10.059.

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Wang, Zhi-Nan, Tian Liang, Wei-Wei Xing, Ai-Bing Du, Ming Gao, Ying-Che Ma, and Kui Liu. "σ-Phase Precipitation Mechanism of 15Cr–15Ni Titanium-Modified Austenitic Stainless Steel During Long-Term Thermal Exposure." Acta Metallurgica Sinica (English Letters) 31, no. 3 (July 6, 2017): 281–89. http://dx.doi.org/10.1007/s40195-017-0624-1.

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Qin, X. Z., J. T. Guo, C. Yuan, C. L. Chen, and H. Q. Ye. "Effects of Long-Term Thermal Exposure on the Microstructure and Properties of a Cast Ni-Base Superalloy." Metallurgical and Materials Transactions A 38, no. 12 (November 7, 2007): 3014–22. http://dx.doi.org/10.1007/s11661-007-9381-5.

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Melicher, Dacotah, Alex S. Torson, Tanner J. Anderson, George D. Yocum, Joseph P. Rinehart, and Julia H. Bowsher. "Immediate Transcriptional Response to a Temperature Pulse under a Fluctuating Thermal Regime." Integrative and Comparative Biology 59, no. 2 (June 7, 2019): 320–37. http://dx.doi.org/10.1093/icb/icz096.

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Abstract The response of ectotherms to temperature stress is complex, non-linear, and is influenced by life stage and previous thermal exposure. Mortality is higher under constant low temperatures than under a fluctuating thermal regime (FTR) that maintains the same low temperature but adds a brief, daily pulse of increased temperature. Long term exposure to FTR has been shown to increase transcription of genes involved in oxidative stress, immune function, and metabolic pathways, which may aid in recovery from chill injury and oxidative damage. Previous research suggests the transcriptional response that protects against sub-lethal damage occurs rapidly under exposure to fluctuating temperatures. However, existing studies have only examined gene expression after a week or over many months. Here we characterize gene expression during a single temperature cycle under FTR. Development of pupating alfalfa leafcutting bees (Megachile rotundata) was interrupted at the red-eye stage and were transferred to 6°C with a 1-h pulse to 20°C and returned to 6°C. RNA was collected before, during, and after the temperature pulse and compared to pupae maintained at a static 6°C. The warm pulse is sufficient to cause expression of transcripts that repair cell membrane damage, modify membrane composition, produce antifreeze proteins, restore ion homeostasis, and respond to oxidative stress. This pattern of expression indicates that even brief exposure to warm temperatures has significant protective effects on insects exposed to stressful cold temperatures that persist beyond the warm pulse. Megachile rotundata’s sensitivity to temperature fluctuations indicates that short exposures to temperature changes affect development and physiology. Genes associated with developmental patterning are expressed after the warm pulse, suggesting that 1 h at 20°C was enough to resume development in the pupae. The greatest difference in gene expression occurred between pupae collected after the warm pulse and at constant low temperatures. Although both were collected at the same time and temperature, the transcriptional response to one FTR cycle included multiple transcripts previously identified under long-term FTR exposure associated with recovery from chill injury, indicating that the effects of FTR occur rapidly and are persistent.

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Hashimoto, Kaho, Zhengtao Ai, and Arsen Melikov. "Airborne transmission during short-term events under stratum ventilation." E3S Web of Conferences 111 (2019): 01098. http://dx.doi.org/10.1051/e3sconf/201911101098.

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Past studies on airborne spread of expiratory droplet nuclei between occupants were focused on long-term exposure under steady-state conditions. However, exposure during short-term events can be widely found in practice, e.g. medical examination or short meeting. Airborne transmission during short-term events under stratum ventilation was examined experimentally in this study. Two breathing thermal manikins were employed to simulate a standing infected person and a standing exposed person. The manikins were placed face-to-face and face-to-back to reproduce the exposure conditions with the highest and the lowest risk, respectively. Tracer gas was dosed into the air exhaled by the “infected” manikin to simulate the droplet nuclei. A newly developed average exposure index was used to evaluate the exposure risk. The time-averaged exposure index increases over time, but the increasing rate depends strongly on the duration of exposure time, e.g., the exposure index increases much faster during the first 5 minutes than during the period after 5 minutes. The exposure index during short-term events does not always decrease with the increase of separation distance. These findings imply that the control measures formulated based on steady-state conditions are not necessarily effective to short-term events.

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Feidantsis, Konstantinos, Ioannis A. Giantsis, Andreas Vratsistas, Stavroula Makri, Athanasia-Zoi Pappa, Elena Drosopoulou, Andreas Anestis, et al. "Correlation between intermediary metabolism, Hsp gene expression, and oxidative stress-related proteins in long-term thermal-stressed Mytilus galloprovincialis." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 319, no. 3 (September 1, 2020): R264—R281. http://dx.doi.org/10.1152/ajpregu.00066.2020.

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Long-term exposure of Mytilus galloprovincialis to temperatures beyond 26°C triggers mussel mortality. The present study aimed to integratively illustrate the correlation between intermediary metabolism, hsp gene expression, and oxidative stress-related proteins in long-term thermally stressed Mytilus galloprovincialis and whether they are affected by thermal stress magnitude and duration. We accordingly evaluated the gene expression profiles, in the posterior adductor muscle (PAM) and the mantle, concerning heat shock protein 70 and 90 ( hsp70 and hsp90), and the antioxidant defense indicators Mn-SOD, Cu/Zn-SOD, catalase, glutathione S-transferase, and the metallothioneins mt-10 and mt-20. Moreover, we determined antioxidant enzyme activities, oxidative stress through lipid peroxidation, and activities of intermediary metabolism enzymes. The pattern of changes in relative mRNA expression levels indicate that mussels are able to sense thermal stress even when exposed to 22°C and before mussel mortality is initiated. Data indicate a close correlation between the magnitude and duration of thermal stress with lipid peroxidation levels and changes in the activity of antioxidant enzymes and the enzymes of intermediary metabolism. The gene expression and increase in the activities of antioxidant enzymes support a scenario, according to which exposure to 24°C might trigger reactive oxygen species (ROS) production, which is closely correlated with anaerobic metabolism under hypometabolic conditions. Increase and maintenance of oxidative stress in conjunction with energy balance disturbance seem to trigger mussel mortality after long-term exposure at temperatures beyond 26°C. Eventually, in the context of preparation for oxidative stress, certain hypotheses and models are suggested, integrating the several steps of cellular stress response.

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Yuan, Chao, Huan Wang, Jian Ting Guo, and He Yong Qin. "Effect of Long-Term Aging on Microstructure and Mechanical Properties of a Wrought Ni-Base Superalloy." Materials Science Forum 816 (April 2015): 546–50. http://dx.doi.org/10.4028/www.scientific.net/msf.816.546.

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During long-term and high temperature service, microstructures of superalloys may change and then have an adverse impact on mechanical properties, so the stabilities of a wrought Ni-base superalloy aging without stress at 650°C were investigated in this paper. The results showed that the size and morphology of γ' precipitates in the alloy were not obviously influenced with the increase of exposure time, and primary MC carbides present excellent thermal stability. Moreover, almost no detrimental phase was found. Tensile strength and plasticity at room temperature after aging remained steady. Under the condition of 650°C/823MPa, the stress ruptures life presented increasing trend overall and plasticity decreases slightly. In conclusion, the experiment alloy presents a good thermal stability at 650°C.

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Yamamoto, Kengo, and Giuseppe Pezzotti. "Nano-Scale Evaluation of Surface Morphology Before and After Environmental Exposure In Vitro of an Advanced Alumina/Zirconia Composite for Arthroplastic Applications." Advances in Science and Technology 76 (October 2010): 224–28. http://dx.doi.org/10.4028/www.scientific.net/ast.76.224.

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In view of the imminent release on the Japanese market of hip prostheses made of an advanced alumina/zirconia, we performed morphologic and spectroscopic assessments of their surfaces with high spatial resolution. Femoral heads were characterized to a degree of statistical accuracy in the as-received state and after long-term exposures in vapor-moist environment. Surface and sub-surface screening was made by atomic force microscopy (AFM) and by confocal Raman spectroscopy, respectively. AFM scanning was systematically repeated with nanometer resolution on portions of surface as large as several tens of micrometers, randomly selected on the head surface, while in-depth scanning by the Raman probe allowed non-destructive analysis of phase structure in the sub-surface slab of material. Polymorphic transformation in zirconia was confined to the first few micrometers below the surface and involved no significant increase in surface roughness even after long-term environmental exposure. Surface roughness lied in a range <10 nm after environmental exposures up to 100 h, corresponding to an exposure time in vivo of several human lifetimes (i.e., according to experimentally derived thermal activation energy).

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Wangyao, Panyawat, Sureerat Polsilapa, Surang Singmaneesakulchai, and Aimamorn Promboopha. "Effect of Thermal Exposure on Long-Term Heated Microstructures at 900°C of Nickel Base Superalloy Turbine Blade, Grade Inconel 738." Key Engineering Materials 658 (July 2015): 19–24. http://dx.doi.org/10.4028/www.scientific.net/kem.658.19.

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The objectives of this research are to search for the most appropriate heat treatment condition for rejuvenating microstructure of cast nickel base superalloy, grade IN-738, turbine blades after using to prolong its life time service again. The turbine blades that had been used for long term service under load and high temperatures resulted in small gamma prime particles connecting to each other and thus forming into larger particles. This effect generally reduces creep resistance and increases the failure. In this research, 5 IN-738 superalloy samples were reheat-treated under simulation of 2 working conditions. First, they were heated at 900oC. At every 400 hours from the beginning of heat treatment until time reaching 1600 hours, these samples were collected and examined the microstructures, size and area fraction of gamma prime particles. Another heating program, they received an over thermal exposure heating at 1125oC for 1 hour after long-term heated at 900oC after every 400 hours-heating. Then the results were analyzed from working conditions. It was found that the sample passed solutioning at 1125oC for 4 hours and aging at 845oC for 24 hours with the over thermal exposure showed the most stable phase stability with γ’ phase increasing after long-term simulated working conditions .

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Journal articles on the topic 'Long-term thermal exposure'

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