检索结果-南通市图书馆

Investigation of the fluid flow in an isolated rotor-stator system with a peripheral opening

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 745-754页

作者： DEBUCHY Roger ABDEL NOUR Fadi NAJI Hassane BOIS Gérard Laboratoire Génie Civil & géo-Environnement (LGCgE- EA 4515) UArtois/FSA Béthune F-62400 Béthune France Université Lille Nord de France F-59000 Lille France damascus university Department of Water Engineering Damascus Syria LML-PRES Lille Nord de France Arts et Métiers ParisTech Lille France

This paper deals with an experimental, theoretical and numerical study of a turbulent flow with separated boundary layers between a rotor and a stator. The system is not subjected to any superimposed radial flow. The periphery of the cavity is opened to the atmosphere so that the solid body rotation for infinite discs is not always observed. Emphasis was placed on develop- ment of an asymptotic approach and a step-by-step method to compute the radial distribution of the core swirl ratio and the static pressure on the stator side. The theory also includes the radial and axial velocities in the core region. The numerical simulation has been conducted with the commercial CFD code Fluent 6.1. The k- SST turbulence model is used, with the assumption of 2D-axisymmetric and steady flow. CFD validations have been performed by comparison of the numerical results with the corresponding theoretical results. Numerical and experimental results are in good agreement with analytical solutions.

关键词： rotor-stator cavity analytical solution numerical simulations k- SST turbulence model

A Comparison between Supra-Scarpa’s Fascia Abdominoplasty and Traditional Abdominoplasty: Effect of Caesarian Section

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

Modern Plastic Surgery 2021年第2期11卷 37-48页

作者： Ali Alrida Rahal Sinan Alboudi Mhd Husam Alhilbawi Mohamad Raghid Hasan Anwar Alhassanieh Division of Plastic and Reconstructive Surgery Department of Surgery Faculty of Medicine Damascus University Damascus Syria

Background: Abdominoplasty is still among the most popular surgeries in the world of cosmetic surgery, as many modifications have been implemented on this surgery to improve aesthetics and reduce the ratio of complication, especially seroma. Also, the duration to drain removal increases the risk of infection, and this can be avoided by preserving the Scarpa’s fascia. Methods: The study was performed from January 2018 to December 2020. The patients were divided into two groups: group A with patients who were performed in Supra-Scarpa’s fascia abdominoplasty, and group B who were performed in traditional abdominoplasty;then group A was divided into two subgroups (A1 with caesarean history and A2 with no caesarean history) that differ in caesarean history or not, while a comparison was done between the groups regarding early outcomes. Results: A total of 40 full abdominoplasties were preformed (group A, 19 patients;group B, 21 patients);then group A was divided into two subgroups (group A1, 13 patients;A2, 6 patients);we found that the time until drain removal and its drain output in group A is less with a statistical significance, and the seroma was less to happen in group A with no statistical significance. However, the operative time in group A is higher with statistical significance. In the subgroups A1 and A2, there was no statistically significant difference in the results. Conclusion: Preservation of the Scarpa’s fascia reduces the time until drain removal, total drain output and the occurrence of seroma and the caesarean scar doesn’t affect the efficacy of preserving the Scarpa’s fascia.

关键词： Abdominoplasty Scarpa’s Fascia Caesarian Section

Using the stent-in-stent technique to drain the right hepatic duct,passing across a 7-year-old obstructed spiral self-expandable metal stent of the left hepatic duct

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Gastroenterology Report 2020年第6期8卷 476-478,I0003页

作者： Ahmad Alhamid Ziad Aljarad Fayez Sandouk Internal Medicine Faculty of MedicineUniversity of AleppoAleppoSyria Department of Gastroenterology Aleppo University HospitalAleppoSyria Gastroenterology Specialty Center DamascusSyria

Introduction Endoscopic stent implantation is a widely used and accepted palliative procedure for non-operated malignant hilar biliary obstruction[1].Several studies have demonstrated that selfexpandable metal stents(SEMS)are superior to plastic stents(PS)[2,3].However,it is still debated whether bilateral stenting is better than unilateral stenting[2,3].Park et *** the literature and clarified that bilateral stenting is favored,due to better clinical outcomes and fewer late complications[2].It is technically challenging to place two SEMS beside each other in order to do bilateral stenting[1,2].For the above considerations,a new technique called‘stent-in-stent’(SIS)has been developed[1].In this method,a Y-stent with a central open mesh allows a second stent to be introduced into the contralateral bile duct[1],resulting in a technical success ranging from 80%to 100%[2].

关键词：右肝管 obstruction

Study the Specifications of the Thread through the Construction of the Pipe on the Ring Spinning Machine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Biomedical Science and Engineering 2015年第4期8卷 295-319页

作者： Mohamad Yaser Joha Easa Morad Postgraduate Student (Msc.) Department of Mechanical Engineering of Textile Industries and Their Technologies Faculty of Mechanical and Electrical Engineering Damascus University Damascus Syria Ass. Prof. Mechanical Department Faculty of Mechanical and Electrical Engineering Damascus University Damascus Syria

In ring spinning, tension develops in the yarn mainly because, to move the Traveler and the balloon length, Lb, around the spindle axis, and to wind the yarn onto the spinning bobbin, work must be done against the frictional force of the ring on the Traveler and of the Traveler on the yarn, as well as against the air drag on the Traveler and on the balloon length. This work is additional to that needed to overcome the friction of the spindle bearings and the air drag on the forming yarn package. The tensions in the yarn during ring spinning may be considered with respect to three zones: 1) the yarn formation zone (i.e., the zone between the pigtail lappet guide and the front rollers of the drafting system);2) the winding zone (i.e., the zone between the Traveler and the bobbin forming zone);3) the balloon zone (i.e., the zone between the Traveler and lappet guide), where the yarn tension changes noticeable shape by relation with Winding Qatar (the yarn tension increases whenever Winding Qatar reduces).

关键词： The Yarn Formation Zone The Winding Zone The Balloon Zone

Prepared of Olive Oil Doped SiO<sub>2</sub>via Sol-Gel Technique

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2013年第5期3卷 239-243页

作者： Fawaz Nasro Saiof Mohammed Alwan Hamza College of Science Baghdad University Baghdad Iraq Higher Institute for Laser Research Damascus University Damascus Syrian

Olive oil doped Nanosilica is successfully prepared by wet chemical synthesis method. Samples were analyzed by a variety of techniques, including X-ray diffraction, FTIR, absorption and emission spectrometers to report the capability of Sol-Gel technology on preparing of silica monolith as a host material for Olive oil, and investigate the effect of converting Olive oil to a solid state on its optical properties. Some absorption bands of Olive oil are disappearing from absorption spectrum of doped silica. Only single strong fluorescence peak was appearing in fluorescence spectrum of pure Olive oil at wavelength around 678 nm which attributed to chlorophylls, while fluorescence spectrum to doped sample shows two strong fluorescence peaks at the wavelength 681 nm and 585 nm which attributed to chlorophylls and Vitamin E respectively. The doping process enhances fluorescence activity of Olive oil through enhancing intensity of the fluorescence peak corresponding to Vitamin E. Absorption and fluorescence spectrums to doped silica sample give a good indication in direction of using Sol-Gel technique to prepare?for Olive oil doped SiO2 as an optical active material.

关键词： Sol-Gel SiO2 Olive Oil

Exploring of Water Distillation by Single Solar Still Basins

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Climate Change 2013年第1期2卷 57-61页

作者： Ghassan A. Al-hassan Salem A. Algarni Mechanical Engineering Department Damascus University Damascus Syria Mechanical Engineering Department King Khalid University Abha Saudi Arabia

The lack of potable water poses a big problem in Syria. The underground water, where exists, is usually brackish and cannot be used as it is for drinking purposes. Syria lies in high solar isolation band and the vast solar potential can be exploited to convert saline water to potable water. The most economical and easy way to accomplish this objective is using solar still. The purpose of the project is to evaluate the potential of using a solar still basin. To implement this goal three similarly solar still basins have been designed, manufactured and tested in selected day for saline water in month of November, 2010. Each solar still consists of insulated metal box with channels. Pyramidal glass covers attached to the basin at an angle (α = 45°). The three basins have divided into three models (M1, M2 and M3). Before taking the measurement of the distilled water three different amount of water used, so for the (model M1) 3 liter of water, (model M2) 6 liter and (model M3) 9 liter, to study and evaluate the effect of water depth in the basin. The average daily output was found to be (3.924) liters/day for model (M1), (3.116) liters/day for model (M2) and 2.408 liters/day for model (M3) for basin area of 1 m2 based on data of selected day.

关键词： Solar Still Single Basin Syria

Review: Nitrogen Utilization Features in Cotton Crop

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2015年第7期6卷 987-1002页

作者： Nour Ali Department of Crop Cultivation and Farmings Huazhong Agricultural University Wuhan China Department of Field Crop Sciences Agricultural College Damascus University Damascus Syria

Cotton is one of the important cash crops and a fiber crop most widely grown and the highest yielding as well. Cotton fiber is woven to be the fabrics commonly used in our daily life due to its excellent performance and great production in the world, especially in China. To access to such high quantities must ensure the requirements of materials such as nutrients for plant growth and take care of the smallest details to make the production cost less, to improve the utilization efficiency, such as nitrogen (N) fertilizer. Hence, N fertilization studies are not only about the dosages, timing and ratio, but also the uptake processes by the plant, N effect on cotton yield and its formation, as well as the movement and metabolism within the plant. As economic and ecological issues are concerned, economizing N fertilization is paid more and more attention. Many approaches have been done and suggested in order to improve NUE like combine the plant sensing techniques and precision application. Simulations and recent field trials demonstrate that site-specific nitrogen management helped reduce technological constraints to higher AE achievement, profit and more sustainable N management. Therefore, improving nitrogen use efficiency (NUE) is one of the key points to ensure cotton production development sustainable. In this review, we try to highlight the accomplishments of N effect on cotton growth and yield, NUE and factors related to NUE in cotton production based on the current knowledge, and from our viewpoint we propose some possible approaches to improve NUE through N managements in terms of application splits, rates, and timing.

关键词： Cotton Growth Yield Nitrogen Nitrogen Use Efficiency (NUE)

The Behavior of Multi-Story Buildings Seismically Isolated System Hybrid Isolation (Friction, Rubber and with the Addition of Rotational Friction Dampers)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Earthquake Research 2015年第1期4卷 1-13页

作者： Alaa Barmo Imad H. Mualla Hala T. Hasan Department of Structural Engineering Higher Institute of Seismic Research and Studies University of Damascus Damascus Syria DAMPTECH Ltd Technical University of Denmark Lyngby Denmark

Increasing buildings’ resistance to earthquake forces is not always a desirable solution especially for the building contents that are irreplaceable or simply more valuable than the actual primary structure (e.g. museums, data storage Centre’s, etc.). Base isolation and seismic dampers can be employed to minimize inter-story drifts and floor accelerations via specially designed isolation and dampers system at the structural base, or at higher levels of the superstructure. In this research, we’ll examine the response of buildings isolated using isolation system hybrid consisting of Lead-Rubber Bearings (LRB), Flat Sliding Bearings (FSB), with the addition of Rotation Fiction Damper (FD) at the base, then compare the results with buildings that have traditional foundation, in terms of the (period, displacement and distribution shear force and height of the building). It conducts TIME HISTORY seismic analysis for some varying height buildings (eight, twelve, sixteen, and twenty stories), with help of SAP2000 using an earthquake acceleration-time history for (El- Centro). The results show that the use of insulation system Hybrid has had a significant impact on improving the performance of origin in terms of reducing displacements and base shear with in-creasing height of the building, but has had a negative impact on the drift, which leads to an in-crease in drift with the increased flexibility of the building.

关键词： Seismic Isolation Basement Isolation Response of Buildings The Passive Control Damping Drift

An Integrated GIS/RS Approach for Soil Erosion Assessment and Modeling in Syrian Coastal Soils

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2001年第2期11卷 167-174页

作者： M．AL－ABED SHIZHOU 等 GeneralOrganizationofRemoteSensing（Gors） P.O.Box12586Damascus（Syria） InstituteofAgriculturalRemoteSensingandInformationSystemApplication ZhejiangUniversityHangzhou310029（China）

An integrated remote sensing (RS) and geographic information system (GIS) technique was employed to characterize the spatial distribution of the risk of soil erosion by water on Latakia district, Syria. The universal soil loss equation (USLE) was used to calculate the annual soil loss rates for Latakia soils. Mainly, remote sensing data, soil survey, land use inventory, elevation data and climatic atlases are used as resource data sets to generate USLE factor values. The results revealed that integration of GIS/RS with USLE was a practical and effective approach for monitoring soil erosion over large areas.

关键词： geographic information system remote sensing soil erosion universal soil loss equation (USLE)