检索结果-南通市图书馆

Thermodynamic Performance Analysis of Geothermal Power Plant Based on Organic Rankine Cycle (ORC) Using Mixture of Pure Working Fluids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy Engineering 2024年第8期121卷 2023-2038页

作者： Abdul Sattar Laghari Mohammad Waqas Chandio Laveet Kumar mamdouh El Haj Assad Department of Mechanical Engineering Mehran University of Engineering and TechnologyJamshoro76062Pakistan Department of Mechanical and Industrial Engineering College of EngineeringQatar UniversityDoha00000Qatar Sustainable&Renewable Energy Engineering Department University of SharjahSharjah00000United Arab Emirates

The selection of working fluid significantly impacts the geothermal ORC’s *** a mixture as a working fluid is a strategy to improve the output of geothermal *** the current study,modelling and thermodynamic analysis of ORC,using geothermal as a heat source,is carried out at fixed operating *** model is simulated in the Engineering Equation Solver(EES).An environment-friendly mixture of fluids,i.e.,R245fa/R600a,with a suitable mole fraction,is used as the operating *** mixture provided the most convenient results compared to the pure working fluid under fixed operating *** impact of varying the evaporator pressure on the performance parameters,including energy efficiency,exergy efficiency and net power output is *** system provided the optimal performance once the evaporator pressure reached the maximum *** efficiencies:Energy and Exergy,and Net Power output of the system are 16.62%,64.08%and 2199 kW for the basic cycle and 20.72%,67.76%and 2326 kW respectively for the regenerative cycle.

关键词： Organic rankine cycle internal heat exchanger moderate-temperature geothermal source mixture of the fluid exergy

Measuring Impact of Lean Manufacturing Tools for Continuous Improvement on Economic Sustainability

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 Systems Science and Systems Engineering 2024年第4期33卷 452-474页

作者： Luis Javier Márquez Figueroa Jorge Luis García-Alcaraz Ahmed I.Osman Alfonso Jesús Gil López Yashar Aryanfar Mika Sillanpää mamdouh El Haj Assad Department of Electrical Engineering and Computer Science Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico Department of Industrial Engineering and Manufacturing Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico School of Chemistry and Chemical Engineering Queens UniversityBelfastNorthern IrelandUK Department of Economic and Managerial Sciences University of La RiojaLa RiojaSpain Department of Chemical Engineering University of JohannesburgJohannesburgSouth Africa Department of Sustainable and Renewable Energy Engineering University of SharjahSharjahUAE

Using Lean Manufacturing(LM)tools in production processes is crucial for companies’economic,environmental,and social sustainability *** study shows a structural equation model(SEM)that shows the relationship between LM Tools like Kaizen(KAI),Gemba(GEM),Value Stream Mapping(VSM)and Key Performance Indicator(KPI)with Economic Sustainability(ECS).Seven hypotheses were evaluated with data from 179 responses to a questionnaire about the Mexican maquiladora industry,showing that these variables are *** a 95%confidence level,the model was evaluated using the partial least squares *** findings indicate that the relationships between KAI and GEM and KAI and VSM have the strongest relationship,followed by VSM and ECS;however,VSM has the strongest effect on *** on these findings,it is recommended that managers adopt a continuous improvement(KAI)approach based on working directly on the shop floor(GEM and VSM)to support their decisions regarding economic growth(ECS).

关键词： Lean manufacturing economic sustainability structural equation model quality improvement

Activation Energy of Nitriding Medium Carbon Ferromanganese Alloy

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 Iron and Steel Research International 2013年第1期20卷 58-61,78页

作者： Saeed N Ghali mamdouh M eissa Micheal L Mishreky Steel Technology Department Central Metallurgical Research and Development Institute (CMRDI)Helwan 11421CairoEgypt

Investigation of some kinetics aspects of the reaction between nitrogen and medium carbon ferromanganese （MC-FeMn） was made. Nitriding process of fine medium carbon ferromanganese was carried out at temperature ranging from 973 to 1 223 K and time up to 480 min. Nitriding was carried out under nitrogen and hydrogen gas pressures. At temperature of 573 K, hydrogen gas was injected with pressure of about 0.2 MPa followed by injection of nitrogen gas up to 1.2 MPa. Sample mass was 35 g, nitrided in cylindrical chamber with 34 mm in inner diameter and 1 200 mm in length. The change in nitrogen pressure was taken as an indication for nitrogen pickup. The mass gain i.e. nitrogen pickup in kilograms per surface area （m2） was determined by time at different temperatures. Nitriding rate constants were calculated and the activation energy of nitriding process was derived from Arrhenius equation. The nitriding rate constant was found to be increased by increasing temperature of the reaction. The activation energy of nitriding process of fine medium carbon ferromanganese at time ranging up to 28 800 s is around 140 kJ/mol. It was found that the rate controlling step of the nitriding process of MC-FeMn is diffusion mechanism.

关键词： nitriding ferromanganese gas solid reaction activation energy

Effect of cooling rate and composition on microstructure and mechanical properties of ultrahigh-strength steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2019年第12期26卷 1350-1365页

作者： Mohammed Ali David Porter Jukka Komi mamdouh eissa Hoda El Faramawy Taha Mattar Materials and Mechanical Engineering Centre for Advanced Steels ResearchUniversity of OuluOulu 90014Finland Steel Technology Department Central Metallurgical Research and Development InstituteHelwanCairo 11421Egypt

The influence of cooling rate on the microstructure and mechanical properties of two new ultrahigh-strength steels(UHSSs)with different levels of C,Cr and Ni has been evaluated for the as-cooled and untempered *** UHSS had higher contents of C and Cr,while the other one had a higher Ni *** the basis of dilatation curves,microstructures,macrohardness and microhardness,continuous cooling transformation diagrams were constructed as a guide to heat treatment *** rates(CRs)of 60,1 and 0.01°C/s were selected for more detailed *** characterization was made by laser scanning confocal microscopy,field emission scanning electron microscopy combined with electron backscatter diffraction,electron probe microanalysis and X-ray *** properties were characterized using macrohardness,tensile and Charpy V-notch impact *** with the higher C and Cr contents showed lower transformation temperatures and slower bainite formation kinetics than that with the higher Ni *** cooling rates led to lower volume fractions and carbon contents of retained austenite together with finer prior austenite grain size,as well as effective final grain size and lath *** changes were accompanied by higher yield and tensile *** best combinations of strength and toughness were obtained with martensitic microstructures and by avoiding the formation of granular bainite accompanied by proeutectoid carbides at low *** the cooling rates studied,UHSS with the higher C and Cr contents showed the higher hardness and strength but at the cost of toughness.

关键词： Ultrahigh-strength steel Electroslag remelting Continuous cooling transformation diagram Microstructure feature Mechanical property

Parameters Affecting Energy Consumption for Producing High Carbon Ferromanganese in a Closed Submerged Arc Furnace

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 Iron and Steel Research International 2014年第7期21卷 666-672页

作者： Azza Ahmed Hossam Halfa Mohamed K.El-Fawakhry Hoda El-Faramawy mamdouh eissa Steel Technology Metallurgical Research and Development Institute

The power consumption is considered to be the most important factor affecting the production cost of fer romanganese alloy. Different parameters affecting the energy consumption for industrial production of high carbon ferromanganese HCFeMn were investigated in a closed submerged arc furnace. The analysis of industrial data revealed that the most energy consumed factors were the direct reduction by solid carbon, Boudouard reaction, metal and slag formation, and decomposition of fluxing materials （limestone and dolomite）. To reduce the energy con- sumption and minimize the energy losses in the production process of HCFeMn, it was recommended to use Mn blend with minimum Mn to Fe ratio of 6 and lower SiO2 content or higher basicity. The added coke must be adjusted according to the material balance to prevent the over-coke and to minimize the highly endothermic ＂Boudouard reac tion＂. In addition, it was recommended to work at basic slags with the ratio of （CaO＋MgO） to Si（）2 equal to 1.0- 1.2 instead of much higher slag basicity. Furthermore, the mass losses had to be minimized through adjusting the handling and charging process and to take care of all metal produced.

关键词： high carbon ferromanganese production energy consumption carbonate decomposition Boudouard reaction slag basicity energy loss

Effect of Microalloying Additions on the Microstructure and Mechanical Properties of Low Carbon Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 246-251页

作者： eissa mamdouh ABD El-Aziz Ahmed GHALI Saeed HALFA Hossam SABER Shady Central Metallurgical Research & Development Institute "CMRDI" Faculty of Material Science and Engineering German University in Cairo "GUC"

Low carbon steels are characterized by good weldability,formability and fracture toughness ***,the low strength levels of these steel grades limit their wide *** the other hand,increasing the strength by increasing the carbon content and alloying elements deteriorates the other *** this study,the microalloying technique was used to examine the possibility of attaining low carbon steels with good combination of strength,ductility and impact properties.A low carbon steel microalloyed with single addition of vanadium and another one microalloyed with combined addition of vanadium and titanium were used in this investigation and their properties were compared with non-microalloyed low carbon steel having the same base ***,other two nonmicroalloyed and V-microalloyed steels with higher carbon,silicon and manganese contents were also investigated to reveal the effect of base ***,hardness,room and zero temperature Charpy V-notch impact tests were conducted to evaluate the variations in the mechanical properties of low carbon hot forged steel containing vanadium and combinations of vanadium and *** addition,the microstructures of the different investigated steels were observed using both optical microscope and scanning electron ***,the hardness of the ferrite phase was also determined using micro-hardness *** results showed improvement of the mechanical properties of the investigated steels by both single V-and combined V + ***,hardness and impact tests results indicated that good combinations of strength,ductility and impact properties can be achieved by V-microalloying *** with combination of V and Ti microaddition has much higher hardness,yield strength,ultimate tensile strength and impact energy at both room and zero temperatures compared with non-microalloyed and single Vmicroalloyed *** C,Si and Mn contents result in

关键词： low carbon steels single microalloying combined microalloying strength ductility impact energy grain refinement precipitation strengthening

基于动态语料库的阿拉伯语报纸年度特色词探究——以沙特阿拉伯《利雅得报》为例

在线全文

学校读者我要写书评

暂无评论

语言学研究

语言学研究 2024年第1期 166-180页

作者： Alaa mamdouh Akef 王莹莹杨尔弘北京大学 100871 北京语言大学 100083

本文借鉴中国对流行语的监测和盘点工作,定义和提取阿拉伯语年度特色词,以期通过历年年度特色词的动态变化来观测一个阿拉伯国家的风云变幻。本文首先针对阿拉伯语的语言特点,定义了“年度特色词”,进而提出结合搭配词定量分析的年度特... 详细信息

本文借鉴中国对流行语的监测和盘点工作,定义和提取阿拉伯语年度特色词,以期通过历年年度特色词的动态变化来观测一个阿拉伯国家的风云变幻。本文首先针对阿拉伯语的语言特点,定义了“年度特色词”,进而提出结合搭配词定量分析的年度特色词提取方法;最终按照时间顺序提取出沙特阿拉伯《利雅得报》2005—2017年共13年的年度特色词,并以主题的形式梳理出这个国家在政治、经济、军事、外交、反恐以及女权等方面的重要事件,从中感知沙特这13年来历时两位君主所经历的社会发展变革。

关键词：阿拉伯语特色词流行语语言监测语料库语言学

Charcoal Nanoparticles as a Delivery System for Doxorubicin and Sorafenib in Treatment of Hepatocellular Carcinoma

在线全文

学校读者我要写书评

暂无评论

Advances in Nanoparticles 2024年第3期13卷 45-60页

作者： Aisha Elgurashi Abdulla Toga Khalid Mohamed Gader Marvit Osman Widdatallah Omer Abdullah E. Gouda Samah mamdouh Mohamed A. Shemis Department of Clinical Pharmacy Faculty of Pharmacy University of Medical Sciences and Technology Khartoum Sudan Department of Pharmacology Faculty of Pharmacy University of Medical Sciences and Technology Khartoum Sudan Department of Biochemistry and Molecular Biology Theodor Bilharz Research Institute Giza Egypt

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer and one of the leading causes of cancer-related death worldwide. Advanced HCC displays strong resistance to chemotherapy, and traditional chemotherapy drugs do not achieve satisfactory therapeutic efficacy. The delivery of therapeutic compounds to the target site is a major challenge in the treatment of many diseases. Objective: This study aims to evaluate activated charcoal nanoparticles as a drug delivery system for anticancer agents (Sorafenib and Doxorubicin) in Hepatocellular Cancer Stem Cells. Method: The percent efficiency of entrapment (% EE) of the doxorubicin and sorafenib entrapped onto the activated charcoal was obtained by determining the free doxorubicin and sorafenib concentration in the supernatant-prepared solutions. Then the characterizations of nanoparticles were formed by determination of the particle size distribution, zeta potential, and polydispersity index (PDI). The anticancer activity of activated Charcoal, Doxorubicin-ACNP, sorafenib-ACNP, free doxorubicin, and free sorafenib solutions was measured based on cell viability percentage in HepG2 cell lines (ATCC-CCL 75). In vitro RBC’s toxicity of Doxorubicin/sorafenib loaded charcoal was estimated by hemolysis percentage. Results: The synthesized Doxorubicin-ACNP and Sorafenib-ACNP were evaluated and their physiochemical properties were also examined. Essentially, the percent Efficiency of Entrapment (EE %) was found to be 87.5% and 82.66% for Doxorubicin-ACNP and Sorafenib-ACNP, respectively. The loading capacity was 34.78% and 24.31% for Doxorubicin-ACNP and Sorafenib-ACNP. Using the Dynamic Light scattering [DLS] for the determination of the hydrodynamic size and surface zeta potential, a narrow sample size distribution was obtained of (18, 68, and 190 nm for charcoal, 105, 255, and 712 nm for doxorubicin, and 91, 295, and 955 nm for sorafenib), respectively. A surface charge of −13.2, −15.6 and −17 was obta

关键词： Activated Charcoal Nanoparticles (ACNP) Drug Delivery System Sorafenib and Doxorubicin Hepatocellular Cancer Stem Cells

Calcium channel α2δ1 subunit as a novel biomarker for diagnosis of hepatocellular carcinoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cancer Biology & Medicine 2018年第1期15卷 52-60页

作者： Sana Amhimmid Badr Maryan Waheeb Fahmi Manal mahmoud Nomir mamdouh Mohammad El-Shishtawy Biochemistry Department Faculty of Pharmacy Medical Oncology Unit Internal Medicine DepartmentFaculty of Medicine Clinical Pathology Department Students Hospital Mansoura University

Objective:Hepatocellular carcinoma(HCC)is the fifth most common malignancy *** identification of new simple,inexpensive and highly accurate markers for HCC diagnosis and screening is *** case-control study evaluates the role of annexin A2 and voltage-gated calcium channelsα2δ1 subunit as serum biomarkers for HCC ***:The study comprised three groups:group 1,50 patients with an initial diagnosis of HCC associated with chronic hepatitis C virus infection;group 2,25 patients diagnosed with chronic hepatitis C virus infection and cirrhosis without any evidence of HCC;and group 3,15 healthy *** participants were subjected to clinical and laboratory investigations,and radiological *** serum levels of alpha-fetoprotein(AFP),annexin A2,and theα2δ1 subunit were evaluated by using ELISA ***:The serum levels of annexin A2 significantly increased in patients with HCC(10.4±2.5 ng/m L;P<0.001)or with cirrhosis(9.31±1.8 ng/m L;P<0.001)comparing to that of healthy controls(0.296±0.09 ng/m L).However,there was no significant difference in serum annexin A2 levels in patients with HCC comparing to those with ***α2δ1 subunit significantly increased in patients with HCC(20.12±3.7 ng/m L)comparing to that in patients with cirrhosis(10.41±3.4 ng/m L,P<0.001)and healthy controls(10.2±2.9 ng/m L,P<0.001).Conclusions:The serumα2δ1 subunit may function as a new biomarker for HCC ***,serum annexin A2 has low diagnostic value as an HCC marker,especially in patients with underlying cirrhosis.

关键词： Hepatocellular carcinoma tumor initiation cell marker α2δ1 subunit annexin A2 alpha-fetoprotein