The Experts below are selected from a list of 168990 Experts worldwide ranked by ideXlab platform
Terence G Langdon - One of the best experts on this subject based on the ideXlab platform.
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effect of Temperature Rise on microstructural evolution during high pressure torsion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Yuki Hashiguchi, Pedro Henrique R Pereira, Kaveh Edalati, Terence G LangdonAbstract:Abstract Dynamic recrystallization occurs at room Temperature during high-pressure torsion (HPT) leading to the formation of ultrafine grains with high angles of misorientation. There are questions concerning whether dynamic recrystallization occurs due to the Temperature Rise during severe plastic deformation or due to the effect of lattice defects. In this study, the real Temperature Rise was measured by directly placing a thermocouple separately on disc samples of tin, aluminum, silver, copper and titanium. The measurements, which are consistent with finite element simulations, show that the Temperature Rise is of minor significance in initiating dynamic recrystallization. A relationship is developed to predict the Temperature Rise in HPT.
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modeling the Temperature Rise in high pressure torsion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Pedro Henrique R Pereira, Roberto B Figueiredo, Terence G Langdon, Paulo Roberto Cetlin, Yi HuangAbstract:Experiments and finite element modeling were used to estimate the Temperature Rise during high-pressure torsion. The results show the Temperature Rise is dependent upon the material strength, the rotation rate, the sample radius, the heat capacity and the volume of the anvils. A general relationship is derived which predicts the Temperature Rise in samples of different geometries processed using different anvil sizes. A simplified version of the equation is presented for general use.
Srinivasan Ramachandran - One of the best experts on this subject based on the ideXlab platform.
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comparison of Temperature Rise in the pulp chamber with different light curing units an in vitro study
Journal of Conservative Dentistry, 2010Co-Authors: A Rajesh V Ebenezar, R Anilkumar, Rajamani Indira, Srinivasan RamachandranAbstract:Aims/Objectives : This in vitro study was designed to measure and compare the Temperature Rise in the pulp chamber with different light curing units. Materials and Methods : The study was done in two settings-in-vitro and in-vivo simulation. In in-vitro setting, 3mm and 6mm acrylic spacers with 4mm tip diameter thermocouple was used and six groups were formed according to the light curing source- 3 Quartz-Tungsten-Halogen (QTH) units and 3 Light-Emitting-Diode (LED) units. For the LED units, three modes of curing like pulse-cure mode, fast mode and ramp mode were used. For in-vivo simulation, 12 caries free human third molar tooth with fused root were used. K-type thermocouple with 1 mm tip diameter was used. Occlusal cavity was prepared, etched, rinsed with water and blot dried; bonding agent was applied and incremental curing of composite was done. Thermal emission for each light curing agent was noted. Results : Temperature Rise was very minimal in LED light cure units than in QTH light cure units in both the settings. Temperature Rise was minimal at 6mm distance when compared to 3 mm distance. Among the various modes, fast mode produces the less Temperature Rise. Temperature Rise in all the light curing units was well within the normal range of pulpal physiology. Conclusion : Temperature Rise caused due to light curing units does not result in irreversible pulpal damage.
G R Ter Haar - One of the best experts on this subject based on the ideXlab platform.
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Temperature Rise recorded during lesion formation by high intensity focused ultrasound
Ultrasound in Medicine and Biology, 1997Co-Authors: R L Clarke, G R Ter HaarAbstract:Temperature Rise was observed as a function of time in liver and dog prostate tissue ex vivo during heating with high-intensity focused ultrasound. The Temperature Rise was measured using a needle thermocouple placed at the focus. The Temperature vs. time behaviour closely followed the predictions of a model based on bulk and surface heating. When the tissue Temperature was raised above 50°C, an increase in heating rate was seen. At higher Temperatures, a point was reached at which a marked, irreversible change of tissue properties was observed, consistent with protein denaturation. The change was sometimes accompanied by a sudden further Rise in Temperature followed by an equally sudden fall. On dissection, regions of tissue damage (lesions) were seen, sometimes containing bubbles consistent with acoustic cavitation or vaporisation.
Nilgun Ozturk - One of the best experts on this subject based on the ideXlab platform.
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pulpal Temperature Rise during light activated bleaching
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Ayce Unverdi Eldeniz, Serdar Usumez, Aslihan Usumez, Nilgun OzturkAbstract:The purpose of this study was to measure intrapulpal Temperature Rise induced by two kinds of bleaching gels when the tooth was exposed to a variety of light-curing units and a diode laser in vitro. The root portions of 80 extracted intact human maxillary central incisors were sectioned with a carborundum disk approximately 2 mm below the cementoenamel junction perpendicular to the long axis of the teeth. Two bleaching agents containing heat-enhancing colorant was applied to the labial surface. Light-curing units used were a conventional halogen (40 s), a high-intensity halogen (30 s), a light-emitting diode unit (40 s), and a diode laser (15 s). The Temperature Rise was measured in the pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Ten specimens were used for each system and bleaching-agent combination. Differences between the starting Temperature and highest Temperature reading were taken and the calculated Temperature changes were averaged to determine the mean value in Temperature Rise. Temperature Rise values were compared using two-way analysis of variance (ANOVA) at a preset α of 0.05. Temperature Rise varied significantly depending on curing unit and diode laser used. The diode laser induced significantly higher Temperature increases than any other curing unit (11.7°C). The light-emitting diode unit produced the lowest Temperature changes (6.0°C); however, there were no statistically significant differences among the curing units and there were no statistically significant differences between bleaching agents. Light activation of bleaching materials with diode laser caused higher Temperature changes as compared to other curing units and the Temperature Rise detected was viewed as critical for pulpal health. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 254–259, 2005
Pedro Henrique R Pereira - One of the best experts on this subject based on the ideXlab platform.
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effect of Temperature Rise on microstructural evolution during high pressure torsion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Yuki Hashiguchi, Pedro Henrique R Pereira, Kaveh Edalati, Terence G LangdonAbstract:Abstract Dynamic recrystallization occurs at room Temperature during high-pressure torsion (HPT) leading to the formation of ultrafine grains with high angles of misorientation. There are questions concerning whether dynamic recrystallization occurs due to the Temperature Rise during severe plastic deformation or due to the effect of lattice defects. In this study, the real Temperature Rise was measured by directly placing a thermocouple separately on disc samples of tin, aluminum, silver, copper and titanium. The measurements, which are consistent with finite element simulations, show that the Temperature Rise is of minor significance in initiating dynamic recrystallization. A relationship is developed to predict the Temperature Rise in HPT.
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modeling the Temperature Rise in high pressure torsion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Pedro Henrique R Pereira, Roberto B Figueiredo, Terence G Langdon, Paulo Roberto Cetlin, Yi HuangAbstract:Experiments and finite element modeling were used to estimate the Temperature Rise during high-pressure torsion. The results show the Temperature Rise is dependent upon the material strength, the rotation rate, the sample radius, the heat capacity and the volume of the anvils. A general relationship is derived which predicts the Temperature Rise in samples of different geometries processed using different anvil sizes. A simplified version of the equation is presented for general use.
