This work proposes a numerical investigation on the effects of damage on the structural response of Reinforced Concrete(RC)bridge structures commonly adopted in highway and railway networks.An effective three-dimensio...This work proposes a numerical investigation on the effects of damage on the structural response of Reinforced Concrete(RC)bridge structures commonly adopted in highway and railway networks.An effective three-dimensional FE-based numerical model is developed to analyze the bridge’s structural response under several damage scenarios,including the effects of moving vehicle loads.In particular,the longitudinal and transversal beams are modeled through solid finite elements,while horizontal slabs are made of shell elements.Damage phenomena are also incorporated in the numerical model according to a smeared approach consistent with Continuum Damage Mechanics(CDM).In such a context,the proposed method utilizes an advanced and efficient computational strategy for reproducing Vehicle-Bridge Interaction(VBI)effects based on a moving mesh technique consistent with the Arbitrary Lagrangian-Eulerian(ALE)formulation.The proposed model adopts a moving mesh interface for tracing the positions of the contact points between the vehicle’s wheels and the bridge slabs.Such modeling strategy avoids using extremely refined discretization for structural members,thus drastically reducing computational efforts.Vibrational analyses in terms of damage scenarios are presented to verify how the presence of damage affects the natural frequencies of the structural system.In addition,a comprehensive investigation regarding the response of the bridge under moving vehicles is developed,also providing results in terms of Dynamic Amplification Factor(DAFs)for typical design bridge variables.展开更多
Penile prosthetic implantation represents a cornerstone for patients with organic erectile dysfunction(ED)that is refractory,unsatisfactory,or contra-indicated for other approved medical or mechanical options.In this ...Penile prosthetic implantation represents a cornerstone for patients with organic erectile dysfunction(ED)that is refractory,unsatisfactory,or contra-indicated for other approved medical or mechanical options.In this study,we introduce the“Ghattas technique,”wherein we constructed a polypropylene mesh sheath that surrounds and is fixed to a 13-mm malleable prosthesis cylinder,which can increase the cylinder diameter for cases that need a larger prosthesis.All patients underwent preoperative evaluation and completed the five-item International Index of Erectile Function questionnaire(IIEF-5).Postoperative outcomes were evaluated by IIEF-5 and Erectile Dysfunction Inventory of Treatment Satisfaction(EDITS)questionnaires at final follow-up.The mean age of the 23 included patients was 57.9(standard deviation[s.d.]:11.4)years and the mean duration of ED was 8.5(s.d.:7.9)years.Erection improvement was determined by comparing mean preoperative and postoperative IIEF-5 scores(8.3[s.d.:3.9]vs 24.6[s.d.:0.6],P<0.001).High treatment satisfaction was determined according to a mean EDITS score of 94.9(s.d.:9.9).The proposed Ghattas technique was safe and effective in our patients,and provides opportunity for cases that need a diameter larger than 13 mm.Further studies are needed to confirm these results.展开更多
Modeling and experiments of the growth of ash deposits during the combustion in a drop tube furnace are presented in this paper.An existing deposition model for ash deposit was used,which involves relationship among t...Modeling and experiments of the growth of ash deposits during the combustion in a drop tube furnace are presented in this paper.An existing deposition model for ash deposit was used,which involves relationship among the force of gravity,elastic rebound and adhesion forces acting at the moment of ash particle impaction.Important parameters of this model were determined by the experimental data.The influence of particle size and velocity on deposit geometry was investigated.The growth of ash deposits involving various inlet velocities,tube diameters and tube arrangements were simulated with dynamic mesh technique in Fluent.The simulation results show that particle normal impacted velocity plays an important role due to elastic bounce force term.Deposited geometry was influenced by side velocity(velocity of inlet⁃2),and large velocity has an obvious effect to change the shape of deposition and postpone the steady time.展开更多
A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. T...A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. Then, advancing front high quality point placement is used to generate internal points with optimal positions and a Delaunay method is used to insert them efficiently. Finally, optimization procedures are used for mesh quality improvements. Several application examples are presented to demonstrate the robustness and efficiency of the proposed meshing scheme.展开更多
Underground geotechnical engineering encounters persistent challenges in ensuring the stability and safety of surrounding rock structures, particularly within rocky tunnels. Rock reinforcement techniques, including th...Underground geotechnical engineering encounters persistent challenges in ensuring the stability and safety of surrounding rock structures, particularly within rocky tunnels. Rock reinforcement techniques, including the use of steel mesh, are critical to achieving this goal. However, there exists a knowledge gap regarding the comprehensive understanding of the mechanical behavior and failure mechanisms exhibited by steel mesh under diverse loading conditions. This study thoroughly explored the steel mesh's performance throughout the entire loading-failure process, innovating with detailed analysis and modeling techniques. By integrating advanced numerical modeling with laboratory experiments, the study examines the influence of varying reinforcement levels and geometric parameters on the steel mesh strength and deformation characteristics. Sensitivity analysis, employing gray correlation theory, identifies the key factors affecting the mesh performance, while a BP (Backpropagation) neural network model predicts maximum vertical deformation with high accuracy. The findings underscore the critical role of steel diameter and mesh spacing in optimizing peak load capacity, displacement, and energy absorption, offering practical guidelines for design improvements. The use of a Bayesian Regularization (BR) algorithm further enhances the predictive accuracy compared to traditional methods. This research provides new insights into optimizing steel mesh design for underground applications, offering an innovative approach to enhancing structural safety in geotechnical projects.展开更多
Inguinal hernia is a prevalent global surgical condition,accounting for millions of repairs annually.Tension-free mesh repair has become the gold standard for both open approaches(e.g.,Lichtenstein repair)and laparosc...Inguinal hernia is a prevalent global surgical condition,accounting for millions of repairs annually.Tension-free mesh repair has become the gold standard for both open approaches(e.g.,Lichtenstein repair)and laparoscopic techniques(e.g.,transabdominal preperitoneal and totally extraperitoneal[TEP]repairs).1,2,3 Guidelines updated in 2018 and 2023 emphasize mesh-based repairs,providing recommendations to optimize outcomes and minimize complications.1,2 Laparoscopic hernia repair,particularly TEP,offers several advantages,such as reduced pain,quicker recovery,and improved cosmetic outcomes.展开更多
The effective valuation of catalyst supports in the catalytic oxidation makes the contribution to understand the support effect of great interest.Here,the role of active substrate in the performance and stability of C...The effective valuation of catalyst supports in the catalytic oxidation makes the contribution to understand the support effect of great interest.Here,the role of active substrate in the performance and stability of CuFe-Co ternary oxides was studied towards the complete catalytic oxidation of CO.The Cu-Fe-Co oxide thin films were deposited on copper grid mesh(CUGM)using one-step pulsed-spray evaporation chemical vapor deposition method.Crystalline structure and morphology analyses revealed nano-crystallite sizes and do me-top-like morphology.Synergistic effects between Cu,Fe and Co,which affect the surface Cu^2+,Fe^3+,Co^3+and chemisorbed oxygen species(O2 and OH)of thin films over the active support and thus result in better reducibility.The thin film catalysts supported on CUGM exhibited attractive catalytic activity compared to the te rnary oxides supported on ine rt grid mesh at a high gas hourly space velocity.Moreove r,the stability in time-on-stream of the ternary oxides on CUGM was evaluated in the CO oxidation for 30 h.The ad opted deposition strategy ofternary oxides on CUGM presents an excessive amount of adsorbed active oxygen species that play an impo rtant role in the complete CO oxidation.The catalysts supported on CUGM showed better catalytic conve rsion than that on inert grid mesh and some literature-reported noble metal oxides as well as transition metal oxides counterparts,revealing the beneficial effect of the CUGM suppo rt in the improvement of the catalytic performance.展开更多
基金supported by Ministry of University and Research(MUR)through the Research Grant“PRIN 2020 No.2020EBLPLS”“Programma Operativo Nazionale(PON)2014-2020”.
文摘This work proposes a numerical investigation on the effects of damage on the structural response of Reinforced Concrete(RC)bridge structures commonly adopted in highway and railway networks.An effective three-dimensional FE-based numerical model is developed to analyze the bridge’s structural response under several damage scenarios,including the effects of moving vehicle loads.In particular,the longitudinal and transversal beams are modeled through solid finite elements,while horizontal slabs are made of shell elements.Damage phenomena are also incorporated in the numerical model according to a smeared approach consistent with Continuum Damage Mechanics(CDM).In such a context,the proposed method utilizes an advanced and efficient computational strategy for reproducing Vehicle-Bridge Interaction(VBI)effects based on a moving mesh technique consistent with the Arbitrary Lagrangian-Eulerian(ALE)formulation.The proposed model adopts a moving mesh interface for tracing the positions of the contact points between the vehicle’s wheels and the bridge slabs.Such modeling strategy avoids using extremely refined discretization for structural members,thus drastically reducing computational efforts.Vibrational analyses in terms of damage scenarios are presented to verify how the presence of damage affects the natural frequencies of the structural system.In addition,a comprehensive investigation regarding the response of the bridge under moving vehicles is developed,also providing results in terms of Dynamic Amplification Factor(DAFs)for typical design bridge variables.
文摘Penile prosthetic implantation represents a cornerstone for patients with organic erectile dysfunction(ED)that is refractory,unsatisfactory,or contra-indicated for other approved medical or mechanical options.In this study,we introduce the“Ghattas technique,”wherein we constructed a polypropylene mesh sheath that surrounds and is fixed to a 13-mm malleable prosthesis cylinder,which can increase the cylinder diameter for cases that need a larger prosthesis.All patients underwent preoperative evaluation and completed the five-item International Index of Erectile Function questionnaire(IIEF-5).Postoperative outcomes were evaluated by IIEF-5 and Erectile Dysfunction Inventory of Treatment Satisfaction(EDITS)questionnaires at final follow-up.The mean age of the 23 included patients was 57.9(standard deviation[s.d.]:11.4)years and the mean duration of ED was 8.5(s.d.:7.9)years.Erection improvement was determined by comparing mean preoperative and postoperative IIEF-5 scores(8.3[s.d.:3.9]vs 24.6[s.d.:0.6],P<0.001).High treatment satisfaction was determined according to a mean EDITS score of 94.9(s.d.:9.9).The proposed Ghattas technique was safe and effective in our patients,and provides opportunity for cases that need a diameter larger than 13 mm.Further studies are needed to confirm these results.
基金Sponsored by the General Programs of the National Natural Science Foundation of China(Grant No.51676058).
文摘Modeling and experiments of the growth of ash deposits during the combustion in a drop tube furnace are presented in this paper.An existing deposition model for ash deposit was used,which involves relationship among the force of gravity,elastic rebound and adhesion forces acting at the moment of ash particle impaction.Important parameters of this model were determined by the experimental data.The influence of particle size and velocity on deposit geometry was investigated.The growth of ash deposits involving various inlet velocities,tube diameters and tube arrangements were simulated with dynamic mesh technique in Fluent.The simulation results show that particle normal impacted velocity plays an important role due to elastic bounce force term.Deposited geometry was influenced by side velocity(velocity of inlet⁃2),and large velocity has an obvious effect to change the shape of deposition and postpone the steady time.
文摘A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. Then, advancing front high quality point placement is used to generate internal points with optimal positions and a Delaunay method is used to insert them efficiently. Finally, optimization procedures are used for mesh quality improvements. Several application examples are presented to demonstrate the robustness and efficiency of the proposed meshing scheme.
基金funded by the National Natural Science Foundation of China(Grant No.52178396).
文摘Underground geotechnical engineering encounters persistent challenges in ensuring the stability and safety of surrounding rock structures, particularly within rocky tunnels. Rock reinforcement techniques, including the use of steel mesh, are critical to achieving this goal. However, there exists a knowledge gap regarding the comprehensive understanding of the mechanical behavior and failure mechanisms exhibited by steel mesh under diverse loading conditions. This study thoroughly explored the steel mesh's performance throughout the entire loading-failure process, innovating with detailed analysis and modeling techniques. By integrating advanced numerical modeling with laboratory experiments, the study examines the influence of varying reinforcement levels and geometric parameters on the steel mesh strength and deformation characteristics. Sensitivity analysis, employing gray correlation theory, identifies the key factors affecting the mesh performance, while a BP (Backpropagation) neural network model predicts maximum vertical deformation with high accuracy. The findings underscore the critical role of steel diameter and mesh spacing in optimizing peak load capacity, displacement, and energy absorption, offering practical guidelines for design improvements. The use of a Bayesian Regularization (BR) algorithm further enhances the predictive accuracy compared to traditional methods. This research provides new insights into optimizing steel mesh design for underground applications, offering an innovative approach to enhancing structural safety in geotechnical projects.
文摘Inguinal hernia is a prevalent global surgical condition,accounting for millions of repairs annually.Tension-free mesh repair has become the gold standard for both open approaches(e.g.,Lichtenstein repair)and laparoscopic techniques(e.g.,transabdominal preperitoneal and totally extraperitoneal[TEP]repairs).1,2,3 Guidelines updated in 2018 and 2023 emphasize mesh-based repairs,providing recommendations to optimize outcomes and minimize complications.1,2 Laparoscopic hernia repair,particularly TEP,offers several advantages,such as reduced pain,quicker recovery,and improved cosmetic outcomes.
基金financial support from the MOST(No.2017YFA0402800)the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103)。
文摘The effective valuation of catalyst supports in the catalytic oxidation makes the contribution to understand the support effect of great interest.Here,the role of active substrate in the performance and stability of CuFe-Co ternary oxides was studied towards the complete catalytic oxidation of CO.The Cu-Fe-Co oxide thin films were deposited on copper grid mesh(CUGM)using one-step pulsed-spray evaporation chemical vapor deposition method.Crystalline structure and morphology analyses revealed nano-crystallite sizes and do me-top-like morphology.Synergistic effects between Cu,Fe and Co,which affect the surface Cu^2+,Fe^3+,Co^3+and chemisorbed oxygen species(O2 and OH)of thin films over the active support and thus result in better reducibility.The thin film catalysts supported on CUGM exhibited attractive catalytic activity compared to the te rnary oxides supported on ine rt grid mesh at a high gas hourly space velocity.Moreove r,the stability in time-on-stream of the ternary oxides on CUGM was evaluated in the CO oxidation for 30 h.The ad opted deposition strategy ofternary oxides on CUGM presents an excessive amount of adsorbed active oxygen species that play an impo rtant role in the complete CO oxidation.The catalysts supported on CUGM showed better catalytic conve rsion than that on inert grid mesh and some literature-reported noble metal oxides as well as transition metal oxides counterparts,revealing the beneficial effect of the CUGM suppo rt in the improvement of the catalytic performance.
