The Experts below are selected from a list of 31995 Experts worldwide ranked by ideXlab platform
C A Dorao - One of the best experts on this subject based on the ideXlab platform.
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detailed experimental investigations on frictional pressure drop of r134a during flow boiling in 5 mm Diameter Channel the influence of acceleration pressure drop component
International Journal of Refrigeration-revue Internationale Du Froid, 2017Co-Authors: Tomasz Muszynski, Rafal Andrzejczyk, C A DoraoAbstract:Abstract This article presents detailed two-phase diabatic pressure drop data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg m −2 s −1 . The obtained data are used as a validation of the void fraction literature models, a set of graphs shows comparisons, for a representative set of experimental conditions, of the two-phase frictional pressure gradients for the adiabatic and diabatic flow. Verification of the acceleration pressure drop predictions for two-phase adiabatic flow showed that all correlations predict that over 60% of experimental data fit in the range of ±30%. The model proposed in this article predicts 63% of presented data within 10% error, and 96% of the data are predicted within 30% error.
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experimental investigations on adiabatic frictional pressure drops of r134a during flow in 5 mm Diameter Channel
Experimental Thermal and Fluid Science, 2017Co-Authors: Rafal Andrzejczyk, Tomasz Muszynski, C A DoraoAbstract:Abstract The article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg/m2 s. The frictional pressure drop was characterized for the refrigerant R134a, for vapor qualities ranging from 0 to 1. Long-time thermal stability of test facility allowed to gather a comprehensive experimental database for two-phase frictional pressure drop including multiple data points in transition and dryout flow regions. The effect of transition region on the peak value of two-phase frictional pressure drop, for literature models and experiment, is recognized. A systematic assessment of predictive techniques for two-phase frictional pressure drop in adiabatic flows for varying vapor quality was conducted. Both qualitative and quantitative analysis of gathered data vs. literature models was presented. Verification of the pressure drop for two-phase adiabatic flow showed that for Zhang and Webb correlation 93% of experimental data fits in the range of ±30%. The model proposed by Thome et al. in other hand predicts almost 33% of data within 10% error, but only 80% of the data is predicted within 30% error. Additional prediction of the peak value of two-phase frictional pressure drop with literature models and the experiment was made.
Ulf Ulmsten - One of the best experts on this subject based on the ideXlab platform.
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urethral pressure increase on effort originates from within the urethra and continence from musculovaginal closure
Neurourology and Urodynamics, 1995Co-Authors: Peter Petros, Ulf UlmstenAbstract:The aim of the study was to determine the contribution of intra-abdominal pressure transmission to urinary continence in the female. Five patients with genuine stress incontinence (GSI) were studied. Pressure transmission was measured in equivalent positions inside and outside the urethra and bladder during the Intravaginal Slingplasty procedure, a surgical operation used for treatment of urinary incontinence, and performed under local anaesthesia. A 6 mm Diameter Channel was created alongside the urethra. Two separate microtransducer catheters appropriately marked for length were inserted, one inside the urethra, and the other inside the described Channel. With the vaginal hammock intact, an average of 10 simultaneous pressure measurements were made intraoperatively in response to coughing and straining in equivalent positions inside the urethra, and directly outside. Significantly higher pressure readings were found inside the urethra (P = 0.0025), indicating that an active component within the urethra may have created this pressure rise. After opening out two suburethral vaginal flaps, large quantities of urine were lost on coughing in all patients Continence was achieved on tightening the suburethral vagina, indicating that an adequately tight vaginal hammock is a critical element in the continence process. The findings of this study question intraabdominal pressure as a mechanism contributing to continence, but support an alternative mechanism, musculovaginal closure of the urethra. © 1995 Wiley-Liss, Inc.
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urethral pressure increase on effort originates from within the urethra and continence from musculovaginal closure
Neurourology and Urodynamics, 1995Co-Authors: Peter Petros, Ulf UlmstenAbstract:The aim of the study was to determine the contribution of intra-abdominal pressure transmission to urinary continence in the female. Five patients with genuine stress incontinence (GSI) were studied. Pressure transmission was measured in equivalent positions inside and outside the urethra and bladder during the Intravaginal Slingplasty procedure, a surgical operation used for treatment of urinary incontinence, and performed under local anaesthesia. A 6 mm Diameter Channel was created alongside the urethra. Two separate microtransducer catheters appropriately marked for length were inserted, one inside the urethra, and the other inside the described Channel. With the vaginal hammock intact, an average of 10 simultaneous pressure measurements were made intraoperatively in response to coughing and straining in equivalent positions inside the urethra, and directly outside. Significantly higher pressure readings were found inside the urethra (P = 0.0025), indicating that an active component within the urethra may have created this pressure rise. After opening out two suburethral vaginal flaps, large quantities of urine were lost on coughing in all patients. Continence was achieved on tightening the suburethral vagina, indicating that an adequately tight vaginal hammock is a critical element in the continence process. The findings of this study question intraabdominal pressure as a mechanism contributing to continence, but support an alternative mechanism, musculovaginal closure of the urethra.
Alberto Cavallini - One of the best experts on this subject based on the ideXlab platform.
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Flow boiling of R1234yf in a 1 mm Diameter Channel.
International Journal of Refrigeration, 2013Co-Authors: Davide Del Col, Stefano Bortolin, Daniele Torresin, Alberto CavalliniAbstract:Abstract Since many HFC refrigerants have relatively large values of GWP, recent development efforts have been initiated to investigate halogenated olefins as possible refrigerants, with fluorinated propene isomers, in particular, having emerged as possible solutions. Specifically, R1234yf has emerged as an R134a replacement for automotive applications. In this paper, the local heat transfer coefficient measured during flow boiling of R1234yf in a 1 mm Diameter circular microChannel is reported and compared to R134a. During tests, the heat is provided to the boiling fluid by using a secondary fluid. Therefore the heat flux is not imposed but instead it is the result of the inlet temperatures of the two fluids and the thermal resistances on the two sides, as it occurs in actual heat exchangers for automotive and air-conditioning applications. Flow boiling tests are carried out at 31 °C saturation temperature and mass fluxes ranging between 200 kg m−2 s−1 and 600 kg m−2 s−1.
Muhammed Ibrahim - One of the best experts on this subject based on the ideXlab platform.
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The penile baculum in monkey (Macaca radiata), rat (Rattus norvegicus), and bat (Pipistrellus mimus) and its functional significance—a mini review
The Journal of Basic and Applied Zoology, 2018Co-Authors: Seppan Prakash, Muhammed IbrahimAbstract:Background Evolution of the penis in sexual method of reproduction had showed complex developmental processes, leading to extreme species variation. The presence and absence of the os penis vary in taxa within mammals indicate adaptive value of the mammalian penis bone, and understanding the diversity is challenging. Surprisingly, little is known about its details. Methods Comparative analysis of the penis with special reference to the os penis (penile baculum) was analyzed in monkey ( Macaca radiata ), rat ( Rattus norvegicus ), and bat ( Pipistrellus mimus ). Results In monkey, the baculum appears like a miniature of a long bone, a clear central medullary cavity, and surrounded by osteons. Similarly, the baculum in rat showed a medullary canal and surrounded by smaller Channels of osteons. In bat, it is seated over the corpus spongiosum that shows a small Diameter Channel which forms the main lamellar bone and appears to be a single osteon or Haversian system. Though microanatomical examination revealed that the presence of vascular and non-vascular structures contribute for penile erection, the presence of the os penis would be helpful for the penis erection and stiffness and vaginal friction. Conclusions Anatomical relationship to other penile elements and its specific functional significance and the explanation for this general adaptive diversity across species is challenging.
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The penile baculum in monkey ( Macaca radiata ), rat ( Rattus norvegicus ), and bat ( Pipistrellus mimus ) and its functional significance—a mini review
The Journal of Basic and Applied Zoology, 2018Co-Authors: Seppan Prakash, Muhammed IbrahimAbstract:Evolution of the penis in sexual method of reproduction had showed complex developmental processes, leading to extreme species variation. The presence and absence of the os penis vary in taxa within mammals indicate adaptive value of the mammalian penis bone, and understanding the diversity is challenging. Surprisingly, little is known about its details. Comparative analysis of the penis with special reference to the os penis (penile baculum) was analyzed in monkey (Macaca radiata), rat (Rattus norvegicus), and bat (Pipistrellus mimus). In monkey, the baculum appears like a miniature of a long bone, a clear central medullary cavity, and surrounded by osteons. Similarly, the baculum in rat showed a medullary canal and surrounded by smaller Channels of osteons. In bat, it is seated over the corpus spongiosum that shows a small Diameter Channel which forms the main lamellar bone and appears to be a single osteon or Haversian system. Though microanatomical examination revealed that the presence of vascular and non-vascular structures contribute for penile erection, the presence of the os penis would be helpful for the penis erection and stiffness and vaginal friction. Anatomical relationship to other penile elements and its specific functional significance and the explanation for this general adaptive diversity across species is challenging.
Rafal Andrzejczyk - One of the best experts on this subject based on the ideXlab platform.
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detailed experimental investigations on frictional pressure drop of r134a during flow boiling in 5 mm Diameter Channel the influence of acceleration pressure drop component
International Journal of Refrigeration-revue Internationale Du Froid, 2017Co-Authors: Tomasz Muszynski, Rafal Andrzejczyk, C A DoraoAbstract:Abstract This article presents detailed two-phase diabatic pressure drop data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg m −2 s −1 . The obtained data are used as a validation of the void fraction literature models, a set of graphs shows comparisons, for a representative set of experimental conditions, of the two-phase frictional pressure gradients for the adiabatic and diabatic flow. Verification of the acceleration pressure drop predictions for two-phase adiabatic flow showed that all correlations predict that over 60% of experimental data fit in the range of ±30%. The model proposed in this article predicts 63% of presented data within 10% error, and 96% of the data are predicted within 30% error.
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experimental investigations on adiabatic frictional pressure drops of r134a during flow in 5 mm Diameter Channel
Experimental Thermal and Fluid Science, 2017Co-Authors: Rafal Andrzejczyk, Tomasz Muszynski, C A DoraoAbstract:Abstract The article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg/m2 s. The frictional pressure drop was characterized for the refrigerant R134a, for vapor qualities ranging from 0 to 1. Long-time thermal stability of test facility allowed to gather a comprehensive experimental database for two-phase frictional pressure drop including multiple data points in transition and dryout flow regions. The effect of transition region on the peak value of two-phase frictional pressure drop, for literature models and experiment, is recognized. A systematic assessment of predictive techniques for two-phase frictional pressure drop in adiabatic flows for varying vapor quality was conducted. Both qualitative and quantitative analysis of gathered data vs. literature models was presented. Verification of the pressure drop for two-phase adiabatic flow showed that for Zhang and Webb correlation 93% of experimental data fits in the range of ±30%. The model proposed by Thome et al. in other hand predicts almost 33% of data within 10% error, but only 80% of the data is predicted within 30% error. Additional prediction of the peak value of two-phase frictional pressure drop with literature models and the experiment was made.