检索结果-南通市图书馆

Hydrodynamic mechanisms of aggressive collapse events in leading edge cavitation

Journal of Hydrodynamics 2020年第1期32卷 6-19页

作者： Mohammad Hossein Arabnejad Ali Amini mohamed farhat Rickard EBensow Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden Laboratory for Hydraulic Machines EPFLLausanneSwitzerland

Transient cavities generated from unsteady leading-edge cavitation may undergo aggressive collapses which are responsible for cavitation *** this paper,we studied the hydrodynamic mechanisms of these events in the leading edge cavitation fonned over a modified NACA0009 hydrofoil using experimental and numerical *** the experimental investigation,high-speed visualization(HSV)and paint test are employed to study the behavior of the cavitating flow at σ=1.25,α=5°,U∞=20 m/*** the numerical part,the same cavitating flow is simulated using an inviscid density-based compressible solver with a barotropic cavitation *** numerical results are first compared with the experimental HSV to show that the simulation is able to reproduce the main features of the cavitating ***,as the compressible solver is capable of capturing the shock wave upon the collapse of cavities,the location of collapse events with high erosion potential are *** location of these collapse events are compared with the paint test results with a qualitatively good *** is clearly observed,in both the experiments and the numerical simulation,that there exists four distinct regions along the hydrofoil with higher risks of erosion:(1)A very narrow strip at the leading edge,(2)an area of accumulated collapses at around 60 percent of the sheet cavity maximum length,(3)an area around the closure line of the sheet cavity with the highest erosion damage,and(4)a wide area close to the trailing edge with dispersed collapse events.A combined analysis of the experimental and numerical results reveals that the small-scale structures generated by secondary shedding are more aggressive than the large-scale cloud cavities(primary shedding).It is also observed that the high risk of cavitation erosion in regions 2 and 3 is mainly due to the collapses of the small cavity structures that are formed around the sheet cavity closure line or the rolling cloud cavity.

关键词： Hydrodynamic mechanisms aggressive collapse events high-speed visualization(HSV) paint test compressible simulation of cavitating flows

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of leading edge roughness on cavitation inception and development on thin hydrofoil

引用

排灌机械工程学报 2017年第11期35卷 921-926,940页

作者： TAO Ran XIAO Ruofu farhat mohamed Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Net- work System China Agricultural University Beijing 100083 China Laboratory for Hydraulic Ma- chines Ecole Polyteehnique Federale de Lausanne Lausanne 1007 Switzerland

The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were *** with smooth and rough leading edge were tested for different upstream velocities and incidence *** observations clearly revealed that cavitation incipience is enhanced by roughness at incidence angle below 2°.This is in line with the former reports,according to whose roughness element decreases the wettability and traps a larger amount of *** a result,surface nucleation is enhanced with an increased risk of ***,for higher incidence angles(>3°),it was found that cavitation incipience is significantly delayed by roughness while developed cavitation is almost the same for both smooth and rough *** unexpected incipience delay is related to the change in the boundary layer structure due to *** was also reported a significant influence of roughness on the dynamic of developed cavitation and shedding of transient cavities.

关键词： cavitation inception surface roughness sheet cavitation cloud cavitation hydrofoil

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A review of cavitation in tip-leakage flow and its control

引用

Journal of Hydrodynamics 2021年第2期33卷 226-242页

作者： Huai-yu Cheng Bin Ji Xin-ping Long Wen-xin Huai mohamed farhat State Key Lab of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan 430072China Laboratory for Hydraulic Machines Ecole Polytechnique Federale de Lausanne(EPFL)LausanneSwitzerland

The tip-leakage vortex(TLV)cavitation is a challenging issue for a variety of axial hydraulic turbines and pumps from both technical and scientific *** flow characteristics of the TLV cavitation were widely studied in the past decades,but the knowledge about the tip-leakage cavitating flow is still *** present paper reviews the progresses in the researches of the TLV cavitation,including the numerical methods for the TLV cavitation,the flow characteristics of the TLV,the influences of the TLV cavitation on the local flow field and the control strategies of the TLV *** is indicated that the non-condensable gas may play an important role in the development of the TLV cavitation,and this fact should be considered during a careful simulation of the TLV *** is also suggested that the development of the TLV cavitation will significantly influence the distributions of the vorticity and the turbulence kinetic *** to the complexity of the TLV cavitation,it is still an open question how to suppress the TLV cavitation in a simple but effective ***,based on these understandings,some advanced topics for the future work are suggested to further promote the study of the TLV cavitation,for a deeper knowledge about the TLV cavitation.

关键词： Cavitation tip-leakage vortex(TLV) cavitation model flow control nuclei

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Recent advances in coherent perfect absorber-lasers and their future applications

引用

Journal of Central South University 2022年第10期29卷 3203-3216页

作者： YANG Min-ye YE Zhi-lu ZHU Liang farhat mohamed CHEN Pai-Yen Department of Electrical and Computer Engineering University of Illinois at ChicagoChicagoIL 60607United States Computer Electricaland Mathematical Science and Engineering DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

In recent years, peculiar physical phenomena enabled by non-Hermitian systems, especially the parity-time(PT)-symmetric systems, have drawn tremendous research interests. Particularly, special spectral degeneracies known as exceptional points(EPs) and coherent perfect absorber-laser(CPAL) points where zero and infinite large eigenvalues coexist are the most popular topics to be studied. To date, the discussions of EPs that serve as transition boundaries between broken PT-symmetry phase and exact PT-symmetry phase have been intensively presented. However, the theoretical analysis and experimental validations of CPAL points are inadequate. Different from EPs, CPAL points, as a special solution of broken PT-symmetry phase, may exhibit even further counterintuitive physical features, which may have significant implications to study non-Hermitian physics. Here, we review some recent advances of CPAL phenomena in different sub-disciplines of physics, including optics, electronics and electromagnetics, and ***, we also provide an envision of future directions and applications of CPAL systems.

关键词： parity-time symmetry coherent-perfect absorber-laser spectral singularities non-Hermitian physics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

射流空蚀过程噪声频谱特征研究

射流空蚀过程噪声频谱特征研究

引用

第三十一届全国水动力学研讨会

作者：曹彦涛彭晓星 mohamed farhat 颜开中国船舶科学研究中心船舶振动噪声重点实验室江苏省绿色船舶重点实验室水力机械实验室洛桑联邦理工学院

空蚀是空化的危害之一,常见于船舶推进器和水力机械等过流部件,其出现会影响相应部件的水动力性能和结构安全性,因此空蚀程度的评估一直备受关注。而空蚀速率与空化强度相关,因此如何评估空化强度是空蚀程度评估的关键。本文通过在射流... 详细信息

空蚀是空化的危害之一,常见于船舶推进器和水力机械等过流部件,其出现会影响相应部件的水动力性能和结构安全性,因此空蚀程度的评估一直备受关注。而空蚀速率与空化强度相关,因此如何评估空化强度是空蚀程度评估的关键。本文通过在射流空蚀试验装置上加装水听器的方式,获得材料空蚀过程噪声信号,以探究利用噪声信号特征判断空化强度的可行性。频谱分析结果显示,噪声特征可以反映同一温度下不同速度引起的空蚀质量损失差异,但无法反映同一速度下、不同温度导致的空蚀质量损失差别。

关键词：射流空化空蚀噪声特征

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Does wet-cupping therapy improve repeated sprint ability,perceived wellness,and rating of perceived exertion in young active males?

引用

Sports Medicine and Health Science 2024年第4期6卷 378-384页

作者： Ismail Dergaa Amine Ghram mohamed Romdhani Amine Souissi Achraf Ammar Ramadan Abdelmoez Farahat mohamed Saifeddin Fessi Khadijeh Irandoust Morteza Taheri Tasnim Masmoudi mohamed Amine Dergaa Nizar Souissi Omar Hammouda Katja Weiss Karim Chamari Helmi Ben Saad Beat Knechtle Primary Health Care Corporation(PHCC) DohaP.O.Box 26555Qatar Research Unit Physical Activity Sportand HealthUR18JS01National Observatory of SportTunis 1003Tunisia High Institute of Sport and Physical Education University of SfaxSfaxTunisia Department of Cardiac Rehabilitation Heart HospitalHamad Medical CorporationDohaQatar Universite de Sousse Faculte de Medecine de SousseHopital Farhat HACHEDLaboratoire de Recherche(Insuffisance CardiaqueLR12SP09)SousseTunisia Healthy Living for Pandemic Event Protection(HL-PIVOT)Network ChicagoILUSA Interdisciplinary Laboratory in Neurosciences Physiology and Psychology:Physical ActivityHealth and LearningUFR STAPSUPLParis Nanterre UniversityNanterreFrance Department of Training and Movement Science Institute of Sport ScienceJohannes Gutenberg-University Mainz55128 MainzGermany Research Laboratory Molecular Bases of Human PathologyLR19ES13Faculty of Medicine of SfaxUniversity of SfaxSfax 3029Tunisia Faculty of Medicine Kafrelsheikh UniversityKafrelsheikh33511Egypt Department of Behavioral and Cognitive Sciences in Sport Faculty of Sport Sciences and HealthUniversity of TehranIran University of Sousse Farhat HACHED HospitalForensic ServiceSousseTunisia Medbase St.Gallen Am Vadianplatz St.GallenSwitzerland Aspetar Orthopaedic and Sports Medicine HospitalFIFA Medical Centre of ExcellenceDohaP.O.Box 29222Qatar Institute of Primary Care University of ZurichZurichSwitzerland

Wet-cupping therapy(WCT)is one of the oldest known medical techniques,used as a traditional and complementary therapy with a wide application all around the world for general *** on the effects of WCT on sports performance are sparse and ***,we aimed to explore the effects of WCT on repeated sprint ability,wellness,and exertion in young active ***-nine active adult males(age:[28±5]years;body height[177±8]cm;body mass:[79±7]kg;body mass index:[25.4±1.8]kg/m^(2))were selected for the *** participants performed a running-based sprint test on two separate occasions(Control and Post-WCT).WCT was performed 24 h before the testing *** completed the Hooper questionnaire to assess their well-being(i.e.,sleep,stress,fatigue,and soreness)before each *** rating of perceived exertion(RPE)was collected after each testing session.A higher maximum power(p<0.05,effect size[ES]=0.6),mean power(p<0.01,ES=0.5)and minimum power(p<0.01,ES=0.6)were recorded post-WCT as compared to Control session along with a better perceived sleep(p<0.01,ES=0.85).Perceived stress(p<0.01,ES=0.6)and RPE(p<0.001;ES=1.1)were lower during the post-WCT compared to the Control *** present findings demonstrated that WCT moderately enhanced repeated sprint ability and had positive effects on perceived sleep,stress,and *** may be an effective ergogenic aid to improve repeated sprint ability and general wellbeing in young adult *** large-scale multicentric clinical studies are paramount to confirm the results of our study.

关键词： Alternative medicine Complementary medicine Hijama Short-term maximal performance Sports medicine

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Outcome of Nurses with Occupational Dermatitis

引用

Open Journal of Nursing 2024年第6期14卷 239-251页

作者： Amira Omrane Chayma Harrathi Asma Kheder Maher Maoua Malek Ben Abdelkader Taoufik Khalfallah Najib Mrizak mohamed Akrout mohamed Adnene Henchi Hichem Bel Hadj Ali Department of Occupational Medicine and Ergonomics Taher Sfar Teaching Hospital Mahdia Tunisia Department of Occupational Medicine Houcine Bouzaiene Teaching Hospital Gafsa Tunisia Department of Occupational Medicine Farhat Hached Teaching Hospital Sousse Tunisia Department of Occupational Medicine and Ergonomics Fattouma Bourguiba Teaching Hospital Monastir Tunisia Department of Dermatology Fattouma Bourguiba Teaching Hospital Monastir Tunisia

Background: Occupational dermatitis is considered as the second most common occupational disease. It accounts for 25% of all lost workdays. Several international studies reported a prevalence of occupational dermatitis in healthcare workers between 17% and 55%. This study aims to identify factors that affect the professional outcome of nurses suffering from occupational dermatitis. Methods: This was a multicenter cross-sectional study concerning nurses declared having occupational dermatitis in the central region of Tunisia. A synoptic sheet related to socio-professional and administrative data was completed. A self-administered Questionnaire going over medical and occupational characteristics was completed during a direct interview. Results: The study involved forty nurses working in four public hospitals in the center of Tunisia. Only 37 workers were included in the study. A professional reclassification was introduced among 19 workers (51% of study population). Work-station adaptation was requested in 14 cases (38%). Exposure to allergens in the workplace was eliminated in 20 cases. Two study participants were transferred to other departments (5.4%) and three people retired (8.1%). A statistically significant association was found between professional reclassification and a history of allergic manifestations (p = 0.003). Similarly, a significant association was found between professional reclassification and the allergic agent (p = 0.014). Workstation layout was significantly associated with a history of allergic manifestations (p = 0.039), the palm hand location (p = 0.04), professional eviction (p Conclusion: This study identified the main factors influencing the occupational outcome of nurses suffering from occupational dermatitis. This outcome depended on a history of atopy (especially allergic rhinitis) and sensitization to allergens (thiuram mix).

关键词： Nursing Occupational Dermatitis Hospital

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pancreatic Gastrointestinal Stromal Tumour: A Case Report and Review of the Literature

引用

Journal of Cancer Therapy 2017年第11期8卷 954-961页

作者： Daadoucha Abderrahmen farhat Waad Ben Mabrouk mohamed Harrabi Fathia Azzaza mohamed Ben Ali Ali Department of Medical Imaging Ibn Al Jazzar University Hospital Kairouan Tunisia Department of Digestive Surgery Sahloul University Hospital Sousse Tunisia

Gastrointestinal stromal tumours (GIST) are rare mesenchymal neoplasms that can develop in the entire length of the gastrointestinal tract or sometimes from the omentum and mesentery. In most cases, they arise from the stomach, less often the jejunum or ileum. We report the case of a 53-year-old-female patient, without significant medical history, consulting for chronic epigastric pain, with no other associated signs. She had underwent an abdominal ultrasound completed with a Contrast-enhanced computed tomography (CT) of the abdomen showing a large tissular mass developed at the expense of the cephalic portion of the pancreas, with central calcifications and heterogeneous enhancement after contrast injection. Pancreaticoduodenectomy, partial colectomy and antrectomy has been performed and histological examination with immunohistochemical study had concluded the diagnosis of pancreatic primary GIST.

关键词： Stromal Tumor Pancreas Imaging Histopathology

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Intra-Abdominal Cystic Lymphangioma: Report of 21 Cases

引用

Journal of Cancer Therapy 2015年第7期6卷 572-578页

作者： mohamed Ben Mabrouk Malek Barka Waad farhat Fathia Harrabi mohamed Azzaza Nefis Abdennaceur Amine Schaidar Abdelkader Mizouni Jaafar Mazhoud Ali Ben Ali Department of Digestive Surgery Sahloul Hospital Sousse Tunisia

Studying in a retrospective review of 21 cases, diagnostic, therapeutic and evolutionary aspects of intra-abdominal cystic lymphangioma (CL). Methods: Between 1992 and 2014, 21 patients were operated at our institution for a CL. Clinical presentation, location, surgical management and outcome were studied. Results: There were 14 women and 7 men. All CL were diagnosed by abdominal ultrasound and/or abdominal CT scan. The most common site was the retroperitoneum (24%) followed by equally by the mesentery, the mesocolon and abdominal wall. Surgical treatment consisted of a complete resection of cyst in 20 patients. This resection required a splenectomy in one case for a splenic location and digestive resection in 2 cases. Two cases of recurrence of CL were revealed. The first case was a result of partial resection, but the second case occurred in a patient who underwent a total cystectomy. These patients were asymptomatic, so we decided to monitor them. Conclusion: CL in adult is a rare disease. The preoperative diagnostic has benefited from the contribution of imaging mainly ultrasound and CT scan, treatment consisted of surgical complete excision to prevent recurrences.

关键词： Cystic Lymphangioma Intra-Abdominal Diagnosis Surgical Treatment Evolution

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Predictive Factors of Surgery in Peptic Stenosis of the Bulb

引用

Open Journal of Gastroenterology 2015年第9期5卷 129-133页

作者： mohamed Ben Mabrouk Aida Ben Slama Trabelsi Mehdi Ksiaa Waad farhat Ali Jmaa Ali Ben Ali Department of Digestive Surgery Sahloul Hospital Sousse Tunisia Department of Gastroenterology Sahloul Hospital Sousse Tunisia

The bulb ulcer stenosis, becoming exceptional in developed countries, remains frequent in our country despite the use of the antisecretory. The purpose of our study was to study epidemiological, diagnostic, and evolutionary complication particularities, and to find potential predictive factors of resistance of ulcer stenosis of the bulb to the pump inhibitors Proton through a recent series. This is a retrospective and descriptive study involving 105 patients, treated for ulcer stenosis of the bulb between January 2007 and December 2012. All our patients had received inhibitors of Proton pump, parenterally for 7 days. They were divided into 2 groups according to their response to treatment: the first group (G1) was sensitive and the second (G2) was resistant. All patients of the G2 were operated. We had compared the two groups. There was no statistically significant difference concerning age, sex, blood group and smoking between the two groups. In univariate study, the age of the epigastralgies was greater than or equal to 9 years;the clapotage fasting, dilation and gastric atony, objectified by the oesogastroduodenal transit were significantly associated with the failure of medical treatment. Only gastric atony and seniority of the disease over 9 years were independent risk factors of resistance to the Proton pump inhibitors in multivariate study.

关键词： Bulbar Ulcer Stenosis Surgery Proton Pump Inhibitors

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：