Friction stir welding using the tools with polygonal pins is often found to improve the mechanical strength of weld joint in comparison to the tools with circular pins. However, the impacts of pin profile on the peak ...Friction stir welding using the tools with polygonal pins is often found to improve the mechanical strength of weld joint in comparison to the tools with circular pins. However, the impacts of pin profile on the peak temperature, tool torque and traverse force, and the resultant mechanical stresses experienced by the tool have been rarely reported in a systematic manner. An estimation of the rate of heat generation for the tools with polygonal pins is challenging due to their non-axisymmetric cross-section about the tool axis. A novel methodology is presented to analytically estimate the rate of heat generation for the tools with polygonal pins. A three-dimensional heat transfer analysis of friction stir welding is carried out using finite element method. The computed temperature field from the heat transfer model is used to estimate the torque, traverse force and the mechanical stresses experienced by regular triangular, square, pentagon and hexagon pins following the principles of solid mechanics. The computed results show that the peak temperature experienced by the tool pin increases with the number of pin sides. However, the resultant maximum shear stress experienced by the pin reduces from the triangular to hexagonal pins.展开更多
AIM: To determine the mechanical properties of anasto- motic colonic tissue in experimental settings and there- fore give a measure of wound healing. METHODS: Thirty-six male Wistar rats were used as ex- perimental mo...AIM: To determine the mechanical properties of anasto- motic colonic tissue in experimental settings and there- fore give a measure of wound healing. METHODS: Thirty-six male Wistar rats were used as ex- perimental models of anastomotic tissue integrity. On the 5th post-operative day, the tensile strength was measured by application of an axial force, providing a quantitative measure of anastomotic dehiscence and leakage. RESULTS: Diagrams of the load as a function of the time [P = P (t)] and of the displacement also as a func- tion of time [Δs = Δs (t)] were recorded for each test, permitting the design of the load versus the displace- ment diagram and thus providing significant data about the critical values of anastomotic failure. Quantitative data were obtained concerning the anastomotic strength of both control specimens (healthy rats), as well as spec- imens from non-healthy rats for comparison. CONCLUSION: This experimental model provides an excellent method of measuring anastomotic strength. Despite the relative small number of specimens used, this method provides an accurate way of measuring wound repair. More experimental measurements need to be performed to correlate emerging tensile strength val-ues to anastomotic failure.展开更多
We have designed a Metamaterial unit-cell for 9 GHz frequency. Periodic structure was used at 4.25 × 4.25 mm with a thickness of 0.35 mm and giving us the 99.99% of absorbance at 9 GHz in simulated results. We ha...We have designed a Metamaterial unit-cell for 9 GHz frequency. Periodic structure was used at 4.25 × 4.25 mm with a thickness of 0.35 mm and giving us the 99.99% of absorbance at 9 GHz in simulated results. We have implemented a rectangular microstrip antenna and loaded it with Metamaterial unit-cells which provided improved results. There were results available for reflection coefficient (s11 parameter) at 9 GHz and also helping for the reduction of the Radar Cross Section of an antenna, which reduced more than 20 dB and not affected its directivity and gain.展开更多
In this paper,study of direct result for a summation-integral type modification of Szasz-Mirakjan operators is carried out.Calculation of moments,density result and a Voronvskaja-type result are also obtained.
This paper aims to estimate segments of latent variables associated with mode choice. The estimates of latent segmentation is obtained through Structural Equation Modelling (SEM) approach. The model is used to identif...This paper aims to estimate segments of latent variables associated with mode choice. The estimates of latent segmentation is obtained through Structural Equation Modelling (SEM) approach. The model is used to identify segments of homogeneous latent variables for attitude towards choice of feeder modes. The Scholars from different nations have contributed greatly in identifying conventional factors affecting the mode choice behavior. Apparently, very few studies have focused on analyzing latent variables affecting the choice of a mode. Specifically, feeder modes, which are likely to increase the mode shift to the public transport mode through improved door- bus stop connectivity. Thus, this study was carried out with an aim to identify the effect of latent variables on the mode choice behavior of the riders for proposed feeder modes. The proposed modes are Environment-Friendly for added benefits of pollution control. The selected study area is the city of Vadodara, in Gujarat state of India. For this, 41 latent variables were identified from the literature review. Data was collected through a predetermined and framed questionnaire. The latent variables with their indicators were checked by preliminary Confirmatory Factor Analysis (CFA), using SPSS software. Six hypotheses were framed to determine the interrelationship between the latent variables through Structural Equation Modelling (SEM) using the Analysis of Moment Structures (AMOS) software. Based on the outliers, communalities extraction and, correlation criteria, the indicators were reduced to 26. The results of the segmental analysis model reveal that the four framed latent variables positively affect the mode choice behavior of a rider. Hence, inculcating these latent variables while proposing an Environment-Friendly feeder mode may result in increased mode choice. Which can be predicted through choice models as a future scope.展开更多
文摘Friction stir welding using the tools with polygonal pins is often found to improve the mechanical strength of weld joint in comparison to the tools with circular pins. However, the impacts of pin profile on the peak temperature, tool torque and traverse force, and the resultant mechanical stresses experienced by the tool have been rarely reported in a systematic manner. An estimation of the rate of heat generation for the tools with polygonal pins is challenging due to their non-axisymmetric cross-section about the tool axis. A novel methodology is presented to analytically estimate the rate of heat generation for the tools with polygonal pins. A three-dimensional heat transfer analysis of friction stir welding is carried out using finite element method. The computed temperature field from the heat transfer model is used to estimate the torque, traverse force and the mechanical stresses experienced by regular triangular, square, pentagon and hexagon pins following the principles of solid mechanics. The computed results show that the peak temperature experienced by the tool pin increases with the number of pin sides. However, the resultant maximum shear stress experienced by the pin reduces from the triangular to hexagonal pins.
文摘AIM: To determine the mechanical properties of anasto- motic colonic tissue in experimental settings and there- fore give a measure of wound healing. METHODS: Thirty-six male Wistar rats were used as ex- perimental models of anastomotic tissue integrity. On the 5th post-operative day, the tensile strength was measured by application of an axial force, providing a quantitative measure of anastomotic dehiscence and leakage. RESULTS: Diagrams of the load as a function of the time [P = P (t)] and of the displacement also as a func- tion of time [Δs = Δs (t)] were recorded for each test, permitting the design of the load versus the displace- ment diagram and thus providing significant data about the critical values of anastomotic failure. Quantitative data were obtained concerning the anastomotic strength of both control specimens (healthy rats), as well as spec- imens from non-healthy rats for comparison. CONCLUSION: This experimental model provides an excellent method of measuring anastomotic strength. Despite the relative small number of specimens used, this method provides an accurate way of measuring wound repair. More experimental measurements need to be performed to correlate emerging tensile strength val-ues to anastomotic failure.
文摘We have designed a Metamaterial unit-cell for 9 GHz frequency. Periodic structure was used at 4.25 × 4.25 mm with a thickness of 0.35 mm and giving us the 99.99% of absorbance at 9 GHz in simulated results. We have implemented a rectangular microstrip antenna and loaded it with Metamaterial unit-cells which provided improved results. There were results available for reflection coefficient (s11 parameter) at 9 GHz and also helping for the reduction of the Radar Cross Section of an antenna, which reduced more than 20 dB and not affected its directivity and gain.
文摘In this paper,study of direct result for a summation-integral type modification of Szasz-Mirakjan operators is carried out.Calculation of moments,density result and a Voronvskaja-type result are also obtained.
文摘This paper aims to estimate segments of latent variables associated with mode choice. The estimates of latent segmentation is obtained through Structural Equation Modelling (SEM) approach. The model is used to identify segments of homogeneous latent variables for attitude towards choice of feeder modes. The Scholars from different nations have contributed greatly in identifying conventional factors affecting the mode choice behavior. Apparently, very few studies have focused on analyzing latent variables affecting the choice of a mode. Specifically, feeder modes, which are likely to increase the mode shift to the public transport mode through improved door- bus stop connectivity. Thus, this study was carried out with an aim to identify the effect of latent variables on the mode choice behavior of the riders for proposed feeder modes. The proposed modes are Environment-Friendly for added benefits of pollution control. The selected study area is the city of Vadodara, in Gujarat state of India. For this, 41 latent variables were identified from the literature review. Data was collected through a predetermined and framed questionnaire. The latent variables with their indicators were checked by preliminary Confirmatory Factor Analysis (CFA), using SPSS software. Six hypotheses were framed to determine the interrelationship between the latent variables through Structural Equation Modelling (SEM) using the Analysis of Moment Structures (AMOS) software. Based on the outliers, communalities extraction and, correlation criteria, the indicators were reduced to 26. The results of the segmental analysis model reveal that the four framed latent variables positively affect the mode choice behavior of a rider. Hence, inculcating these latent variables while proposing an Environment-Friendly feeder mode may result in increased mode choice. Which can be predicted through choice models as a future scope.
