The Experts below are selected from a list of 37389 Experts worldwide ranked by ideXlab platform
Hans Gregersen - One of the best experts on this subject based on the ideXlab platform.
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Opening angle and Residual Strain in a three-layered model of pig oesophagus.
Journal of biomechanics, 2007Co-Authors: Jingbo Zhao, Xudong Chen, Jian Yang, Donghua Liao, Hans GregersenAbstract:Studies of various biological tissues have shown that Residual Strains are important for tissue function. Since a force balance exists in whole wall thickness specimens cut radially, it is evident that layer separation is an important procedure in the understanding of the meaning of Residual stresses and Strains. The present study investigated the zero-stress state and Residual Strain distribution in a three-layer model of the pig oesophagus. The middle part of the oesophagus was obtained from six slaughterhouse pigs. Four 3-mm-wide rings were serially cut from each oesophagus. Two of them were used for separating the wall into mucosa-submucosa, inner and outer muscle layers. The remaining two rings were kept as intact rings. The inner and outer circumferences and wall thickness of different layers in intact and separated rings were measured from the digital images in the no-load state and zero-stress state. The opening angle was measured and the Residual Strain at the inner and outer surface of different layers and the intact wall were computed. Compared with intact sectors (62.8+/-9.8 degrees ), the opening angles were smaller in the inner muscle sectors (37.2+/-11.4 degrees , P 0.1). Referenced to the zero-stress state of the intact sectors, the inner and outer Residual Strains of the intact rings was -0.128+/-0.043 and outer Residual Strain was 0.308+/-0.032. Referenced to the "true" zero-stress state of separated three-layered sectors, the inner Residual Strain of intact rings were -0.223+/-0.021 (P 0.1). In conclusion, it is possible to microsurgically separate the oesophagus into three layers, i.e., mucosa-submucosa, inner muscle and outer muscle layers, the Residual Strain differ between the layers, and the Residual Strain distribution was more uniform after the layers were separated.
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Longitudinal Residual Strain and stress-Strain relationship in rat small intestine.
Biomedical engineering online, 2006Co-Authors: Yanling Dou, Jingbo Zhao, Yanhua Fan, Hans GregersenAbstract:Background To obtain a more detailed description of the stress-free state of the intestinal wall, longitudinal Residual Strain measurements are needed. Furthermore, data on longitudinal stress-Strain relations in visceral organs are scarce. The present study aims to investigate the longitudinal Residual Strain and the longitudinal stress-Strain relationship in the rat small intestine.
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CORRELATION BETWEEN INTESTINAL Residual Strain AND THICKNESS OF DIFFERENT LAYERS OF INTESTINAL WALL IN RATS
Chinese Journal of Biomedical Engineering, 2003Co-Authors: Jingbo Zhao, Yanling Dou, Fengyuan Zhuang, Hans GregersenAbstract:Residual Strain and thickness of different layers of different parts of intestine, including duodenum, jejunum and ileum in normal rats were measured and computed. The correlation between opening angle, Residual Strain and thickness of different intestinal layers also were analyzed . The results showed that the value of Residual Strain was negative inside and positive outside. The absolute value of Residual Strain was largest in the duodenum and smallest in the ileum. The opening angle and Residual Strain were highly correlated to the thickness of intestinal mucosa and submucosa, but not to the thickness of intestinal muscle layer.
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Morphological properties and Residual Strain along the small intestine in rats
World journal of gastroenterology, 2002Co-Authors: Jingbo Zhao, Fengyuan Zhuang, Hong Sha, Hans GregersenAbstract:AIM: Residual stress and Strain are important for gastrointestinal function and relate to the geometric configuration, the loading conditions and the zero-stress state of the gastrointestinal tract. The purpose of this project is to provide morphometric data and Residual Strains for the rat small intestine (n = 11). METHODS: To approach the no-load state, the intestine was surgically excised, transferred to an organ bath and cut transversely into short ring-shaped segments. Each ring was cut radially for obtaining the zero-stress state. The Residual stress can be characterised by an opening angle. The Strain difference between the zero-stress state and the no-load state is called Residual Strain. RESULTS: Large morphometric variations were found along the small intestine. The wall thickness was highest in the proximal duodenum and decreased in distal direction along the axis of the small intestine (P < 0.001). The circumferential length of the inner and outer surfaces decreased rapidly along the length of duodenum by 30%-50% (P < 0.001). The wall area and lumen area showed a similar pattern (P < 0.001). In zero-stress state the rings always opened up after making the cut. The experiments resulted in larger inner circumferential length and smaller outer circumferential length when compared to the no-load state. The wall thickness and wall area did not differ between the no-load and zero-stress state. The opening angle and tangent rotation angle increased along the length of the duodenum and had its highest value 30% down the intestine. Further down the intestine it decreased again (P < 0.001). The serosal Residual Strain was tensile with the highest value close to the ligament of Treitz (P < 0.001). The mucosal Residual Strain was compressive in all segments of the small intestine with average values between -0.25 and -0.4 and with the lowest values close to the ligament of Treitz (P < 0.001). CONCLUSION: Axial variation in morphometric properties and Residual Strains were found in the small intestine. Existence of large Residual Strains indicates that the zero-stress state must be considered in future biomechanical studies in the gastrointestinal tract.
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Morphometry and Residual Strain in porcine ureter.
Scandinavian journal of urology and nephrology, 1999Co-Authors: Ib Tønder Hansen, Hans GregersenAbstract:Recent studies on blood vessels, the heart, trachea and esophagus have shown that these organs in the zero-stress state are not closed circular cross-sections of rings, but open sectors. Any analysis of stress and Strain must begin with organs in the zero-stress state. This report presents data on morphometry of the zero-stress and no-load states of the porcine ureter, and on Residual Strains and opening angles. The zero-stress state of the ureter is demonstrated by cutting the ureter into rings and cutting the rings into sectors; each sector is characterized by an opening angle. The outer and inner circumferences, the cross-sectional area of the ureteral wall and the number of buckles showed axial variation, with the highest values proximally in the ureter. Residual Strain in the circumferential direction was significant, but showed no axial variation. The opening angles were approximately 30 degrees at the most distal and proximal sites and approximately 90 degrees in mid-ureter. The opening angle showed positive correlation to the wall thickness in the zero-stress state, Residual Strain at the outer circumference and negative correlation to the length of the outer circumference in the zero-stress state. Residual Strains must be taken into account when studying physiological problems in which the stresses and Strains are important, e.g. the urine transport function of the ureter.
Takashi Sekiguchi - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of the relation between dislocation density and Residual Strain in silicon ingots used in solar cells
Journal of Crystal Growth, 2017Co-Authors: Satoshi Nakano, Masayuki Fukuzawa, Karolin Jiptner, Yoshiji Miyamura, Takashi Sekiguchi, H Harada, Koichi KakimotoAbstract:Abstract We have developed a three dimensional Haasen-Alexander-Sumino model to investigate the distribution of dislocation density and Residual Strain in Si crystals and compared the calculation results with experimental data performed in mono-like and multicrystalline silicon ingots. The results show that the Residual Strain in a multicrystal is lower than in a mono-like crystal, whereas the dislocation density in the multicrystal is higher than that in the mono-like crystal. This phenomenon is due to the relation between dislocation density and Residual Strain caused by the difference of activated slip systems in a mono-like crystal and a multicrystal.
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Characterization of Residual Strain in Si Ingots Grown by the Seed-Cast Method
Solid State Phenomena, 2013Co-Authors: Karolin Jiptner, Masayuki Fukuzawa, Yoshiji Miyamura, Hirofumi Harada, Koichi Kakimoto, Takashi SekiguchiAbstract:The Residual Strain distribution in cast-grown mono-like Si ingots is analyzed. The effect of the crucible during solidification and the influence of different cooling rates is described. To clarify in which process steps Residual Strain accumulates, several Si ingots were grown in a laboratory scale furnace (100mm) using different cooling conditions after completion of the solidification. For the cooling, two different cooling rates were distinguished: fast cooling (12deg/min) and slow cooling (5deg/min). It was found that changes in cooling gradients greatly influence the amount of Residual Strain. The results show that slow cooling in any temperature range leads to Strain reduction. The greatest reduction could be found when the temperature gradient was changed to slow cooling in the high temperature region.
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evaluation of Residual Strain in directional solidified mono si ingots
Physica Status Solidi (c), 2013Co-Authors: Masayuki Fukuzawa, Karolin Jiptner, Yoshiji Miyamura, Koichi Kakimoto, Takashi Sekiguchi, H HaradaAbstract:Cast-grown mono-like Si ingots for photovoltaic application are getting increasing attention due to the possibility of obtaining highly efficient solar cells at a low-cost production process. The reduction of crystallographic defects is essential to reach that potential. In this study, the Residual Strain and dislocation distribution in monolike ingots grown by directional solidification was experimentally determined. It was found that both Strain and dislocations are mainly concentrated in the periphery of the ingots (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Evaluation of Residual Strain in directional solidified mono‐Si ingots
Physica Status Solidi (c), 2012Co-Authors: Karolin Jiptner, Masayuki Fukuzawa, Yoshiji Miyamura, Hirofumi Harada, Koichi Kakimoto, Takashi SekiguchiAbstract:Cast-grown mono-like Si ingots for photovoltaic application are getting increasing attention due to the possibility of obtaining highly efficient solar cells at a low-cost production process. The reduction of crystallographic defects is essential to reach that potential. In this study, the Residual Strain and dislocation distribution in monolike ingots grown by directional solidification was experimentally determined. It was found that both Strain and dislocations are mainly concentrated in the periphery of the ingots (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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correlation between Residual Strain and electrically active grain boundaries in multicrystalline silicon
Applied Physics Letters, 2008Co-Authors: Jun Chen, Masayuki Fukuzawa, Takashi Sekiguchi, Bin Chen, Masayoki YamadaAbstract:We report the correlation between Residual Strain and electrically active grain boundaries (GBs) in multicrystalline silicon. The former concerns the process yield, and the latter affects the solar cell efficiency. The distribution of Strain was imaged by scanning infrared polariscope, and the electrically active GBs were characterized by electron-beam-induced current. Large Strain was detected near multitwin boundaries and small-angle GBs. The multitwin boundaries are electrically inactive, while small-angle GBs act as strong recombination centers. It indicates that the electrical activities of GBs are not directly related to the Residual Strain.
Joost J. Vlassak - One of the best experts on this subject based on the ideXlab platform.
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poisson s ratio and Residual Strain of freestanding ultra thin films
Journal of The Mechanics and Physics of Solids, 2020Co-Authors: Gayatri Cuddalorepatta, Daniel Pantuso, Lakshminarayanan Mahadevan, Wim M Van Rees, Joost J. VlassakAbstract:Abstract The Poisson’s ratio and Residual Strain of ultra-thin films ( ( 6.8 ± 0.8 ) × 10 − 3 are measured. The measured Residual Strain is in good agreement with the Residual Strain of ( 7.1 ± 0.2 ) × 10 − 3 measured using alternate Residual stress-driven test structures of the same films.
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Poisson’s ratio and Residual Strain of freestanding ultra-thin films
Journal of the Mechanics and Physics of Solids, 2020Co-Authors: Gayatri Cuddalorepatta, Wim M. Van Rees, Li Han, Daniel Pantuso, Lakshminarayanan Mahadevan, Joost J. VlassakAbstract:Abstract The Poisson’s ratio and Residual Strain of ultra-thin films ( ( 6.8 ± 0.8 ) × 10 − 3 are measured. The measured Residual Strain is in good agreement with the Residual Strain of ( 7.1 ± 0.2 ) × 10 − 3 measured using alternate Residual stress-driven test structures of the same films.
Hideki Yuya - One of the best experts on this subject based on the ideXlab platform.
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investigation of electromagnetic nondestructive evaluation of Residual Strain in low carbon steels using the eddy current magnetic signature ec ms method
Journal of Magnetism and Magnetic Materials, 2019Co-Authors: Takanori Matsumoto, Shinji Oozono, Gerd Dobmann, Benjamin Ducharne, Tetsuya Uchimoto, Toshiyuki Takagi, Hideki YuyaAbstract:Abstract A novel magnetic nondestructive testing method, that is named eddy current magnetic signature (EC-MS) method, is proposed to evaluate the Residual Strain in low carbon steels. This method relies on characterization of eddy current signals in the impedance plane if low frequency major magnetization is superimposed. To investigate the mechanism of the proposed method, the eddy current magnetic signatures of a set of tensile test specimens are measured, and their relationship to the Residual Strain is surveyed. The trajectories of the eddy current signals show significant dependences on the Residual Strain; the EC-MS changes depending on the three Residual Strain stages, the region just after elastic limit before yield point, the Luders-Strain region, and the region after start of work hardening. The EC-MS under elastic Strain/stress is measured to investigate the influence of stress on the EC-MS. Numerical calculation is performed considering micro-eddy current field associated with moving domain walls and compared with experimental results to interpret the EC-MS phenomena.
Masayuki Fukuzawa - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of the relation between dislocation density and Residual Strain in silicon ingots used in solar cells
Journal of Crystal Growth, 2017Co-Authors: Satoshi Nakano, Masayuki Fukuzawa, Karolin Jiptner, Yoshiji Miyamura, Takashi Sekiguchi, H Harada, Koichi KakimotoAbstract:Abstract We have developed a three dimensional Haasen-Alexander-Sumino model to investigate the distribution of dislocation density and Residual Strain in Si crystals and compared the calculation results with experimental data performed in mono-like and multicrystalline silicon ingots. The results show that the Residual Strain in a multicrystal is lower than in a mono-like crystal, whereas the dislocation density in the multicrystal is higher than that in the mono-like crystal. This phenomenon is due to the relation between dislocation density and Residual Strain caused by the difference of activated slip systems in a mono-like crystal and a multicrystal.
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Characterization of Residual Strain in Si Ingots Grown by the Seed-Cast Method
Solid State Phenomena, 2013Co-Authors: Karolin Jiptner, Masayuki Fukuzawa, Yoshiji Miyamura, Hirofumi Harada, Koichi Kakimoto, Takashi SekiguchiAbstract:The Residual Strain distribution in cast-grown mono-like Si ingots is analyzed. The effect of the crucible during solidification and the influence of different cooling rates is described. To clarify in which process steps Residual Strain accumulates, several Si ingots were grown in a laboratory scale furnace (100mm) using different cooling conditions after completion of the solidification. For the cooling, two different cooling rates were distinguished: fast cooling (12deg/min) and slow cooling (5deg/min). It was found that changes in cooling gradients greatly influence the amount of Residual Strain. The results show that slow cooling in any temperature range leads to Strain reduction. The greatest reduction could be found when the temperature gradient was changed to slow cooling in the high temperature region.
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evaluation of Residual Strain in directional solidified mono si ingots
Physica Status Solidi (c), 2013Co-Authors: Masayuki Fukuzawa, Karolin Jiptner, Yoshiji Miyamura, Koichi Kakimoto, Takashi Sekiguchi, H HaradaAbstract:Cast-grown mono-like Si ingots for photovoltaic application are getting increasing attention due to the possibility of obtaining highly efficient solar cells at a low-cost production process. The reduction of crystallographic defects is essential to reach that potential. In this study, the Residual Strain and dislocation distribution in monolike ingots grown by directional solidification was experimentally determined. It was found that both Strain and dislocations are mainly concentrated in the periphery of the ingots (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Evaluation of Residual Strain in directional solidified mono‐Si ingots
Physica Status Solidi (c), 2012Co-Authors: Karolin Jiptner, Masayuki Fukuzawa, Yoshiji Miyamura, Hirofumi Harada, Koichi Kakimoto, Takashi SekiguchiAbstract:Cast-grown mono-like Si ingots for photovoltaic application are getting increasing attention due to the possibility of obtaining highly efficient solar cells at a low-cost production process. The reduction of crystallographic defects is essential to reach that potential. In this study, the Residual Strain and dislocation distribution in monolike ingots grown by directional solidification was experimentally determined. It was found that both Strain and dislocations are mainly concentrated in the periphery of the ingots (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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correlation between Residual Strain and electrically active grain boundaries in multicrystalline silicon
Applied Physics Letters, 2008Co-Authors: Jun Chen, Masayuki Fukuzawa, Takashi Sekiguchi, Bin Chen, Masayoki YamadaAbstract:We report the correlation between Residual Strain and electrically active grain boundaries (GBs) in multicrystalline silicon. The former concerns the process yield, and the latter affects the solar cell efficiency. The distribution of Strain was imaged by scanning infrared polariscope, and the electrically active GBs were characterized by electron-beam-induced current. Large Strain was detected near multitwin boundaries and small-angle GBs. The multitwin boundaries are electrically inactive, while small-angle GBs act as strong recombination centers. It indicates that the electrical activities of GBs are not directly related to the Residual Strain.
