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Performance Simulation of a Double Tube Heat Exchanger Based on Different Nanofluids by Aspen Plus

Frontiers in Heat and Mass Transfer 2024年第1期22卷 175-191页

作者： Fawziea M.hussien Atheer S.Hassoon Ghaidaa M.ahmed Fuel and Energy Technologies Engineering Department Baghdad Engineering Technical CollegeMiddle Technical UniversityBaghdad10074Iraq Power Mechanics Techniques Engineering Department Al-Musaib Technical CollegeAl-Furat Al-Awsat Technical University(ATU)Kufa54001Iraq

A heat exchanger’s performance depends heavily on the operating fluid’s transfer of heat capacity and thermal *** nanoparticles of high thermal conductivity materials is a significant way to enhance the heat transfer fluid’s thermal *** research used engine oil containing alumina(Al_(2)O_(3))nanoparticles and copper oxide(CuO)to test whether or not the heat exchanger’s efficiency could be *** establish the most effective elements for heat transfer enhancement,the heat exchangers thermal performance was tested at 0.05%and 0.1%concentrations for Al_(2)O_(3)and CuO *** simulation results showed that the percentage increase in Nusselt number(Nu)for nanofluid at 0.05%particle concentration compared to pure oil was 9.71%for CuO nanofluids and 6.7%for Al_(2)O_(3)*** 0.1%concentration,the enhancement percentage in Nu was approximately 23%for CuO and 18.67%for Al_(2)O_(3)nanofluids,*** a concentration of 0.1%,CuO nanofluid increased the LMTD and overall heat transfer coefficient(U)by 7.24 and 5.91%*** the overall heat transfer coefficient(U)and the heat transfer coefficient(hn)for CuO nanofluid at a concentration of 0.1%increased by 5.91%and 10.68%,*** effectiveness(εn)of a heat exchanger was increased by roughly 4.09%with the use of CuO nanofluid in comparison to Al_(2)O_(3)at a concentration of 0.1%.The amount of exergy destruction in DTHX goes down as Re and volume fractions go ***,at 0.05%and 0.1%nanoparticle concentrations,the percentage increase in dimensionless exergy is 10.55%and 13.08%,***,adding the CuO and Al_(2)O_(3)nanoparticles improved the thermal conductivity of the main fluid(oil),resulting in a considerable increase in the thermal performance and rate of heat transfer of a heat exchanger.

关键词： Nanofluid nusselt number exergy dimensionless exergy destruction double tube heat exchanger performance simulation aspen plus

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The effects of cross-diffusion and radiation on mixed convection from a vertical flat plate embedded in a fluid-saturated porous medium in the presence of viscous dissipation

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Propulsion and Power Research 2016年第2期5卷 149-163页

作者： mohammed A.mohammed ahmed mohammed E.mohammed ahmed A.Khidir Faculty of Technology of Mathematical Sciences and Statistics Alneelain UniversityP.O.Box 12702KhartoumSudan

In this paper,we propose a new application of a recent semi-numericalsuccessive linearization method(SLM)in solving highly coupled,nonlinear boundaryvalue *** method is presented in detail by solving the problem of steady flowof mixed convection and an incompressible viscous hydromagnetic fluid from a verticalflat plate embedded in a fluid-saturated porous *** governing partial differentialequations are transformed into a system of ordinary differential equations and then solvedby *** effects of different physical parameters on the velocity,temperature,andconcentration profiles are determined and *** skin-friction,and heat and masstransfer coefficients have been obtained and analyzed for various physical *** results are presented numerically through graphs and tables for both assistingand opposing flows to observe the effects of various parameters encountered in the equations.

关键词： Successive linearization method Mixed convection Cross-diffusion Heat and mass transfer Viscous dissipation

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Multiple Phase Change Materials for Performance Enhancement of a Solar Dryer with Double Pass Collector

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Energy Engineering 2021年第5期118卷 1483-1497页

作者： ahmed J.Hamad Fawziea M.hussien Johain J.Faraj Engineering Technical College Middle Technical UniversityBaghdadIraq

The fluctuation in drying temperature influences the food products’quality and drying time significantly during the drying process using an indirect solar *** of the effective methods to reduce these variations in the temperature is based on thermal storage materials to control the drying *** experimental investigation is presented in this study to evaluate the performance of an indirect solar dryer with air double pass using multiple phase change materials(PCM)as thermal storage *** PCMs with different melting points are used to store the available heat energy during peak sunshine periods and reduce the drying temperature *** tests on a food product sample are conducted in three cases,the first was without PCMs using natural *** second and third cases are based on forced convection with and without using multiple PCMs under Baghdad city *** results showed that;approximately a steady temperature of hot drying air was obtained during relatively low ambient temperatures when the dryer was incorporated with multiple *** drying time of the product sample for the natural,forced convection without PCMs and forced with PCMs was 87,72 and 47 h,*** higher performance of the dryer was for the forced convection with *** reduction percentage in drying time was about 17.2%and 46%for the forced convection without and with PCMs respectively compared with natural *** average drying rate for the natural,forced without PCMs and forced convection with PCMs was 0.0093,0.0135 and 0.0172 kg/h,*** enhancement in thermal efficiency of the solar collector and drying chamber with multiple PCMs was 43%and 25.5%,respectively,compared with a typical solar dryer.

关键词： Solar dryer double pass indirect dryer multiple PCM drying rate

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On linearization method to MHD boundary layer convective heat transfer with low pressure gradient

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Propulsion and Power Research 2015年第2期4卷 105-113页

作者： mohammed A.mohammed ahmed mohammed E.mohammed ahmed A.Khidir Faculty of Technology of Mathematical Sciences and Statistics Alneelain UniversityKhartoumP.O.Box 12702Sudan

The paper highlights the application of a recent semi-numerical successive linearization method(SLM)in solving highly coupled,nonlinear boundary value *** method is presented in detail by solving the problem of boundary layer convective heat transfer with low pressure gradient in the presence of viscous dissipation and radiation *** effects of the parameters on the flow are *** velocity,temperature,skinfriction,and heat transfer coefficients have been obtained and discussed for various physical parametric values.

关键词： Successive linearization method Magnetohydrodynamics(MHD) Boundary layer convective heat transfer Pressure gradient Viscous dissipation

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Techno-Economic Analysis of a Grid-Connected Waste to Energy Gasification Plant:A Case Study

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Energy Engineering 2021年第6期118卷 1681-1701页

作者： ahmed Abubakar Elwan mohammed Hafiz Habibuddin Department of Electrical Power Engineering Universiti Teknologi MalaysiaJohor Bahru81310Malaysia

With population growth around the world,municipal waste disposal and continued energy demand becomes some of the major challenges to deal *** order to address these,an approach is required for an optimal waste management system that offers the population benefit with a lower environmental *** study evaluates the technical-economic and environmental impact analysis of a grid-connected waste to energy(WtE)plant to power a Univerisiti Teknologi Malaysia(UTM)*** energy recovery potential of the waste stream was assessed using the life cycle assessment(LCA)method with GaBi^(TM) software(version 4).A technical,economic and environmental analysis was then carried out for the grid-connected WtE system using HOMERPro software with gasification conversion *** cash flow analysis was based on levelized costs of energy(LCOE)and total net present value(NPV).The results gave an NPV for the system at USD 1.11×10^(7),with most of the effects resulting from the grid operating costs and the LCOE of USD 0.43/kWh compared to the grid unit price of USD 0.7/kWh which corresponds to a saving of$0.27/kWh in energy *** an environmental point of view,the results showed a significant reduction in carbon dioxide emissions from around 2,000 tons per year to around 400 tons per *** regard to the amount of waste sent to landfills,the results show a significant improvement from 142,605.5 kg/year to 0.13 kg/year.

关键词： Waste to energy techno-economic analysis solid waste gasification

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Professional identity, wellness, and future hope among nurse interns in Egypt

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Frontiers of Nursing 2021年第3期8卷 279-290页

作者： Rasha mohammed hussien Mahmoud Abdul Hameed Shahin Mervat Elshahat Ibrahim Department of Psychiatric Health Nursing Faculty of NursingZagazig UniversityZagazig 423423Egypt Critical Care Nursing Department Mohammed Al-Mana College for Medical SciencesDammam 34222Saudi Arabia Department of Family and Community Health Nursing Faculty of NursingSuez Canal UniversityIsmailia 545345Egypt

Objective:Since nursing is a performance-based profession,clinical learning environments play an important role in the acquisition of professional abilities and train nursing students to enter the nursing profession and become a registered *** study aimed to investigate the relations among professional identity,wellness,and future hope in nurse ***:A cross-sectional,analytic,descriptive,correlational study design was used to test these relations in the study where 210 nurse interns’students were selected using a convenience sampling from Zagazig University hospitals and Suez Canal University hospitals in *** questionnaires consisted of 4 parts,namely demographic characteristics,Professional Identity Scale for Nursing Students(PISNS),Holistic Health and Wellness Survey,and Hope ***:Less than half of the study sample had chosen nursing specialty by own will(43.8%),while slightly more than half of them had a"very good"graduation level,and had no nursing role *** lowest mean professional identity score was for independence in career choice while the highest was for social *** repor ted physical wellness mean-score was the least,while social wellness was the *** identity,wellness,and future hope scores differed significantly based on nurse interns’personal *** were statistically significant,positive,weak-to-moderate correlations among the scores of professional identity,wellness,and future hope;however,the"choice of nursing study by own will"was a statistically significant independent positive predictor of the scores of professional identity,wellness,and future ***:Nurse interns’professional identity,wellness,and future hope were positively ***,nurse interns’wellness was the lowest,and it should be fostered as it was the main predictor for future *** internship programs should be modulated to improve nurse interns’professional identity,par ticularly

关键词： hope identity independence internship nurse interns professional wellness

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The k Nearest Neighbors Estimator of the M-Regression in Functional Statistics

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Computers, Materials & Continua 2020年第12期65卷 2049-2064页

作者： ahmed Bachir Ibrahim Mufrah Almanjahie mohammed Kadi Attouch Department of Mathematics College of ScienceKing Khalid UniversityAbha62529Saudi Arabia Statistical Research and Studies Support Unit King Khalid UniversityAbha62529Saudi Arabia Djillali Liabes University Sidi Belabbes22000Algeria

It is well known that the nonparametric estimation of the regression function is highly sensitive to the presence of even a small proportion of outliers in the *** solve the problem of typical observations when the covariates of the nonparametric component are functional,the robust estimates for the regression parameter and regression operator are *** main propose of the paper is to consider data-driven methods of selecting the number of neighbors in order to make the proposed processes fully *** use thek Nearest Neighbors procedure(kNN)to construct the kernel estimator of the proposed robust *** some regularity conditions,we state consistency results for kNN functional estimators,which are uniform in the number of neighbors(UINN).Furthermore,a simulation study and an empirical application to a real data analysis of octane gasoline predictions are carried out to illustrate the higher predictive performances and the usefulness of the kNN approach.

关键词： Functional data analysis quantile regression kNN method uniform nearest neighbor(UNN)consistency functional nonparametric statistics almost complete convergence rate

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Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

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Frontiers of Structural and Civil Engineering 2021年第6期15卷 1400-1414页

作者： Tarek Uddin mohammed Aziz Hasan MAHMOOD Mohammad Zunaied-Bin-HARUN Jamil ahmed JOY MdAsif ahmed Department of Civil and Environmental Engineering Islamic University of Technology(IUT)Organization of Islamic Cooperation(OIC)Board BazarGazipur 1704Bangladesh Centre for Infrastructure Engineering and Safety School of Civil and Environmental EngineeringThe University of New South WalesSydneyNSW 2052Australia Department of Civil Engineering European University of BangladeshMirpurDhaka 1216Bangladesh

Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical *** such,a detailed experimental investigation was carried out to evaluate the effect of sand-toaggregate volume ratio(s/a)on the mechanical properties of concrete utilizing both destructive and non-destructive testing(employing UPV(ultrasonic pulse velocity)measurements).For investigation,standard cylindrical concrete samples were made with different s/a(0.36,0.40,0.44,0.48,0.52,and 0.56),cement content(340 and 450 kg/m^(3)),water-to-cement ratio(0.45 and 0.50),and maximum aggregate size(12 and 19 mm).The effect of these design parameters on the 7,14,and 28 d compressive strength,tensile strength,elastic modulus,and UPV of concrete were *** careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs;optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm,respectively,irrespective of the W/C(water-to-cement)and cement content.

关键词： aggregates non-destructive testing sand-to-aggregate volume ratio(s/a) maximum aggregate size(MAS)

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Deployment of Polar Codes for Mission-Critical Machine-Type Communication Over Wireless Networks

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Computers, Materials & Continua 2022年第4期71卷 573-592页

作者： Najib ahmed mohammed Ali mohammed Mansoor Rodina Binti Ahmad Saaidal Razalli Bin Azzuhri Department of Software Engineering Faculty of Computer Science and Information TechnologyUniversity of Malaya50603Kuala Lumpur Malaysia 2Department of Computer System&TechnologyFaculty of Computer Science and Information TechnologyUniversity of Malaya50603Kuala LumpurMalaysia

Mission critical Machine-type Communication(mcMTC),also referred to as Ultra-reliable Low Latency Communication(URLLC),has become a research *** is primarily characterized by communication that provides ultra-high reliability and very low latency to concurrently transmit short commands to a massive number of connected *** the reduction in physical(PHY)layer overhead and improvement in channel coding techniques are pivotal in reducing latency and improving reliability,the current wireless standards dedicated to support mcMTC rely heavily on adopting the bottom layers of general-purpose wireless standards and customizing only the upper *** mcMTC has a significant technical impact on the design of all layers of the communication protocol *** this paper,an innovative bottom-up approach has been proposed for mcMTC applications through PHY layer targeted at improving the transmission reliability by implementing ultra-reliable channel coding scheme in the PHY layer of IEEE 802.11a standard bearing in mind short packet transmission *** achieve this aim,we analyzed and compared the channel coding performance of convolutional codes(CCs),low-density parity-check(LDPC)codes,and polar codes in wireless network on the condition of short data packet *** Viterbi decoding algorithm(VA),logarithmic belief propagation(Log-BP)algorithm,and cyclic redundancy check(CRC)successive cancellation list(SCL)(CRC-SCL)decoding algorithm were adopted to CC,LDPC codes,and polar codes,***,a new PHY layer for mcMTC has been *** reliability of the proposed approach has been validated by simulation in terms of Bit error rate(BER)and packet error rate(PER)***-to-noise ratio(SNR).The simulation results demonstrate that the reliability of IEEE 802.11a standard has been significantly improved to be at PER=10−5 or even better with the implementation of polar *** results also show that the general-purpose wireless net

关键词： Machine-type communication mission-critical applications MTC URLLC M2M wireless networks polar codes

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Cross-sectional prevalence and pattern of non-anaemia severe malaria among 2–10 year olds in Sokoto in Northwestern Nigeria

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Frontiers of Medicine 2022年第6期16卷 969-974页

作者： Usman Nasir Nakakana Ridwan Muhammad Jega Aliyu Mamman Nauzo Yahya mohammed Ismaila mohammed ahmed Medical Research Council The Gambia Unit at London School of Hygiene and Tropical MedicineFajara220The Gambia Department of Paediatrics Usmanu Danfodiyo University Teaching HospitalSokoto234Nigeria Department of Paediatrics Federal Medical CentreBirnin Kebbi234Nigeria Department of Microbiology Usmanu Danfodiyo UniversitySokoto234Nigeria Department of Community Medicine Usmanu Danfodiyo University Teaching HospitalSokoto234Nigeria

Malaria is highly prevalent in Nigeria and accounts for approximately 40%of global malaria ***,most reports on severe malaria in Nigeria are from hospital-based studies without accurate information from communities;thus,malaria-related deaths in the community are left *** study aimed to describe the prevalence and pattern of severe malaria in a community in Northwestern Nigeria.A cross-sectional study was conducted among 2–10-year-old children in Sokoto,in August and December 2016,to determine the endemicity of malaria based on Plasmodium falciparum prevalence rate(PfPR2-10)and to describe the disease *** malaria was diagnosed according to the World Health Organisation *** were described using Stata version *** prevalence of non-anaemia severe malaria was higher than expected(2.6%),considering the endemicity pattern which was mesoendemic based on a PfPR2-10 of 34.8%.The mean age of children with severe malaria was 3.73 years,and the male—female ratio was 2:***,54.0%of the patients had hyperparasitaemia.A relatively high prevalence of non-anaemia severe malaria was found in *** finding suggests the need to identify and treat cases in the community using modifications of current strategies,particularly seasonal malaria chemoprophylaxis.

关键词： severe malaria nigeria malaria mortality PfPR2-10 intermediate malaria transmission

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