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Frontiers in Heat and Mass Transfer 2024年第4期22卷 1231-1244页

作者： Ahmed Mustaffa Saleem Abdullah A.Badr Bahjat Hassan Alyas omar rafae alomar Engineering Technical College of Mosul Cultural GroupNorthern Technical UniversityMosul41002Iraq

This study numerically involves the performance of thermal insulation of different types of composite walls and roofs to demonstrate the best model that can be used for energy-efficient building construction in *** mathematical model is solved by building its code using the Transmission Matrix Method in MATLAB *** weather data of 21st July 2022 in Baghdad City/Iraq is selected as a test *** wall types are selected:the first type consists of cement mortar,brick,and gypsum,the second type consists of cement mortar,brick,gypsum,and plaster and the third type consists of cement mortar,brick,gypsum,air cavity,and sheathing *** roof types are chosen:the first type consists of reinforced concrete,gypsum,and plaster,and the second type consists of the precast concrete flag,river sand,tar,reinforced concrete,gypsum,and *** obtained solutions are compared with previous studies for the same city but with different types of walls and *** findings display that the second and third types of walls reduce the entry heat flux by 4%and 10%as compared to the first type of ***,the results indicate that the second type of roof reduces the entry heat flux by 21%as compared to the first type of *** results confirm that the best models of walls and roofs in Iraq are the third and second types,respectively,as compared to other models and hence,the performance of insulation material strongly depends on the materials used while building them.

关键词： Thermal insulation energy gain composites walls and roofs heat flux transmission matrix method

Impacts of Using Al_(2)O_(3)Nano Particle to Compressor Oil on Performance of Automobile Air Conditioning System

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Frontiers in Heat and Mass Transfer 2024年第3期22卷 839-854页

作者： Karam H.Mohammed Ashraf E.Al-Mirani Bashar Mahmood Ali omar rafae alomar Engineering Technical College of Mosul Cultural GroupNorthern Technical UniversityMosul41002Iraq College of Engineering AlNoor UniversityMosul41002Iraq

This work involves an experimental study on the performance of automobile air-conditioning systems by adding Al_(2)O_(3)nanoparticles to oil compressors to investigate their impacts on the enhancement of the speed cooling of refrigeration systems and to compare it with the system operated using only *** Al_(2)O_(3)nanoparticles have been added to the oil compressor for different ranges ofmass concentration(Ф=0.1%,Ф=0.15%andФ=0.2%).The stability of Al_(2)O_(3)nanoparticles has been tested by direct observation for different time *** results indicated that the air conditioning systemthat operated by using Al_(2)O_(3)-oil was better than the system that operated with pure ***Ф=0.2%,the results indicated that the cooling speed and the efficiency of the system operated with Al_(2)O_(3)-oil are increased by 13%and 18%,respectively,as compared to the pure oil *** study shows that the thermos-physical properties of refrigerant oil are enhanced by 15%whenФis increased.

关键词： Nanofluids compressor cooling system automobile cooling system

Effect of Nanomaterials Addition to Phase Change Materials on Heat Transfer in Solar Panels under Iraqi Atmospheric Conditions

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Frontiers in Heat and Mass Transfer 2023年第1期21卷 215-226页

作者： Majid Ahmed Mohammed Abdullah Talab Derea Mohammed Yaseen Lafta Obed Majeed Ali omar rafae alomar Department of Power Mechanics Haweja Technical InstituteNorthern Technical UniversityKirkuk36001Iraq Department of Reconstruction and Projects Ministry of Higher Education and Scientific ResearchBaghdad10065Iraq Department of Physics College of EducationAl-Iraqia UniversityBaghdad10053Iraq Engineering Technical College of Mosul Northern Technical UniversityMosul41002Iraq

It is common knowledge that phase-change materials are used for the purpose of thermal storage because of the characteristics that are exclusive to these materials and not found in *** characteristics include a large capacity for absorbing heat and a large capacity for releasing heat when the phase changes;however,these materials have a low thermal *** paper presents the results of an experimental study that investigated the impact that nanoparticles of copper oxide had on reducing the temperature of solar *** phase change substance that was used was determined to be *** impact of adding nanoscale copper oxide at a concentration of 0.05%of the total mass of wax was investigated and compared to a reference solar panel that did not contain any nanoscale *** findings demonstrated that the incorporation of nanoscale copper oxide brought about a reduction of three℃ in the plate’s average temperature as well as a one percent improvement in its electrical *** cases where it seems that the use of nanoparticles might potentially enhance the performance of integrated solar energy systems that contain phase change.

关键词： Copper oxide nanoparticles nanoparticle beeswax thermal conductivity phase-change materials

Structural, electronic, and optical studies of chalcogenides stannite Cu2CdSnX4（X=S, Se, and Te）: insights from the DFT study

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Optoelectronics Letters 2025年第2期21卷 69-76页

作者： Jamal GUERROUM Mohamed AL-HATTAB Lhoucine MOUDOU Khalid RAHMANI Youssef LACHTIOUI omar BAJJOU Laboratory of Engineering in Chemistry and Physics of Matter Faculty of Sciences and Technics Sultan Moulay Slimane University Ecole Normale Supérieure Mohammed V University in Rabat College of Graduate Studies University of South Africa

In this paper,we have calculated the structural,electronic,and optical properties of chalcogenide stannite Cu2CdSnX4（X=S,Se,Te） *** calculations are based on the density functional theory （DFT） method and are performed using the Cambridge sequential total energy package （CASTEP） code included in the Biovia Material Studio 20 *** optical properties have been studied in a domain that extends energetically from 10 meV to 40 *** results show that Cu2CdSnX4（X=S,Se,Te） stannite exhibits absorption in the visible region,the refractive index decreases with increasing energy,and the refractive index values are n=3.2,3.73 and 3.75 for Cu2CdSnS4,Cu2CdSnSe4and Cu2CdSnTe4,*** show also high conductivity,which implies that this material is promising for solar *** results argue in favor of the use of these materials in various potential *** density of state,band structures,and structural properties of Cu2CdSnX4（X=S,Se,and Te） stannite are also studied in this work.

关键词： Refractive index

Thermospheric neutral wind studies over the equatorial region:A review

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Earth and Planetary Physics 2025年第1期9卷 81-100页

作者： Siti Syazwani Nasuha Idahwati Sarudin Nurul Shazana Abdul Hamid Ahmad Fairuz omar School of Physics Universiti Sains Malaysia11800 USMPulau PinangMalaysia Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia Space Science Centre(ANGKASA) Institute of Climate ChangesUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

Thermospheric neutral winds(TNWs)refer to the neutral gases in the thermosphere circulating as tides,which play a crucial role in the dynamics of the thermosphere-ionosphere system(TIS).Global geospace neutral winds,particularly over the magnetic equator,have been a subject of study for several ***,despite the known importance of neutral winds,a comprehensive understanding and characterization of the winds is still *** ground-based and satellite missions have provided valuable information on the contribution of neutral winds to the global atmospheric ***,efforts in the global monitoring of neutral winds are still lacking,and the drivers behind the behavior of TNWs as well as their influence on the TIS remain *** address these knowledge gaps in the global circulation of TNWs,it is crucial to develop a deep understanding of the neutral wind characteristics over different *** low-latitude equatorial region in particular has been observed to exert complex influences on TNWs because of the unique effects of the Earth’s magnetic field at the dip *** neutral winds over this region will provide valuable insights into the unique dynamics and processes that occur in this region,thereby enhancing our understanding of their role in the overall dynamics of the ***,through empirical observations,an improved ability to accurately model and predict the behavior of this region can be *** review article addresses challenges in understanding equatorial winds by reviewing historical measurements,current missions,and the interactions of ionospheric and thermospheric phenomena,emphasizing the need for comprehensive measurements to improve global atmospheric dynamics and weather forecasting.

关键词： thermospheric neutral wind thermosphere-ionosphere system dip equator equatorial region

Application of solvent evaporation technique for pure drug crystal spheres preparation

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Particuology 2022年第8期20卷 79-89页

作者： omar Mady Department of Pharmaceutical Technology Faculty of Pharmacy Tanta UniversityEgypt

An innovative application ofthe solventevaporation technique was *** tech nique is a technique for drug encapsulation and nanosphere *** widely used technique is also facing the problem of low actual drug entrapment percent,which is not economic from the industrial *** goal of this work is trying to use the advantage of this technique concerning the product sphericity and the ability to control particle size,to prepare a drug as pure crystals *** is selected as a model *** spheres are formed by using Polyvinyl pyrrolidone(PVP)or Polyethylene glycol(PEG)as an anti-aggregating agent but not formed on using tween or *** size and actual drug content depend on the concentrations the anti-aggregating agent *** of the drug crystal spheres are porous with empty sphere internal structure on using PvP but spongy and rough on using *** drug has its identity chemical form in the drug crystal *** scan of spheres prepared on using PEG showed a characteristic ether *** showed melting endothermic peak of PEG,but X-ray showed minor change in the drug crystal *** release profiles from crystal spheres prepared with the same anti-aggregating agent are close to each *** drug release profiles from drug crystal spheres prepared by using PEG are more controlled than that prepared by using *** drug release mechanism is *** was concluded that,the same technique could be suggested for preparation ofother biomedical material in pure crystals spheres with controlled particle *** properties may encourage to prepare very small particles with spherical shape for inhalation or injection as an innovative particle technology application for the widely used technique.

关键词： Solvent evaporation technique Drug crystal spheres Ibuprofen Polyvinyl pyrrolidone Polyethylene glycol

Monolayer MoS_(2)/n-Si Heterostructure Schottky Solar Cell

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Journal of Renewable Materials 2022年第7期10卷 1979-1988页

作者： omar Salih omar The University of Duhok College of ScienceDepartment of PhysicsDuhokKurdistan RegionIraq

Monolayer MoS_(2)has a promising optoelectronics property,with a bandgap in the visible range;the material is a potential candidate for solar cell *** this work,we grew MoS_(2)monolayers using a low-pressure chemical vapor deposition *** produce uniform wafer-scale MoS_(2)monolayer films,precursors molybdenum dioxide(MoO_(2))and sulfur(S)are *** force microscopy was used to quantify the thickness of the monolayers,and the result was validated by Raman *** electron microscopy(TEM)was used to confirm the crystalline quality of the monolayers,and photoluminescence spectroscopy was used to evaluate their optical *** were able to create a Schottky solar cell with a MoS_(2)monolayer up to 1 cm2 area by transferring monolayer film to n-type *** MoS_(2)/n-Si Schottky solar cell demonstrated photovoltaic characteristics with a short circuit current density of 14.8 mA cm^(-2)and an open-circuit voltage of 0.32 V under 100 mW cm^(-2)*** fill factor and energy conversion efficiency were 53%and 2.46%,respectively,with the highest external quantum efficiency at 530 nm being 44%.

关键词： MoS_(2)monolayers chemical vapor deposition Schottky solar cell

VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

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Chinese Journal of Polymer Science 2005年第4期23卷 367-371页

作者： omar Melad omar Abu-Tiem Rajai Baraka Chemistry Department

The viscosity behavior of polyvinylpyrrolidone(PVP)has been determined at 25℃ in mixed solvents comprising water/dimethylformamide(DMF)and water/methanol(MeOH).Analysis of the data has considered the PVP as being both host and guest polymer in *** intrinsic viscosity of PVP in DMF is higher than in water and in MeOH,but also increases in a mixed solvent with high water content because of the effect of polymer-solvent *** was also found that the intrinsic viscosity of PVP at finite concentration,[η_(pvp)]_c decreases with an increase in the concentration of PVP in *** viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect,which can be quantitatively expressed by the parameter,b_Y,which reflects the shrinkage of PVP chain coils,resulting in a decrease of[η_(pvp)]_*** effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value,and then decreases after a certain temperature.

关键词： Polyvinylpyrrolidone Intermolecular excluded volume effect Intrinsic viscosity

Reintegrating nanogranitoid inclusion composition to reconstruct the prograde history of melt-depleted rocks

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Geoscience Frontiers 2019年第2期10卷 517-525页

作者： omar Bartoli Department of Geosciences University of Padova

A recent fascinating development in the study of high-grade metamorphic basements is represented by the finding of tiny inclusions of crystallized melt(nanogranitoid inclusions) hosted in peritectic phases of migmatites and granulites. These inclusions have the potential to provide the primary composition of crustal melts at the source. A novel use of the recently-published nanogranitoid compositional database is presented here. Using granulites from the world-renowned Ivrea Zone(NW Italy) on which the original melt-reintegration approach has been previously applied, it is shown that reintegrating melt inclusion compositions from the published database into residual rock compositions can be a further useful method to reconstruct a plausible prograde history of melt-depleted rocks. This reconstruction is fundamental to investigate the tectonothermal history of geological terranes.

关键词： Nanogranitoids Melt-reintegration Granulite High-temperature metamorphism

Power Reallocation and Complexity Enhancement for Beyond 4G Systems

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China Communications 2019年第6期16卷 114-128页

作者： omar Daoud Communications and Electronics Engineering Department Philadelphia University

Competitiveness in the modern wireless systems’provided services is a key factor in the development,in addition to the adaptation to/harmonization of user ***,this paper discussed the quality of services from the point of view of the need for supporting the needed data *** this purpose,a benchmark based on Multi-Antenna Multiband Orthogonal Frequency Division Multiplexing has been proposed to compatible with Ultra-Wideband systems such as the fifth generation based *** order to enhance the system quality of service,the structure of the ultra-wideband system’s main stage;namely Orthogonal Frequency Division Multiplexing has been modified by imposing a low complexity designed Haar-wavelets stage instead of the fast Fourier transform *** is in addition to reallocate the transmitted power in order to reduce the effect of one of the main drawbacks that is found in the Orthogonal Frequency Division Multiplexing;namely the peak-to-average power ratio problem.A MATLAB simulation has been performed in order to validate the propositions that have been made based on six different performance *** a result,the new propositions were achieved our targets by reducing the system’s complexity in terms of mathematical operations and by giving promising results in managing the transmitted ***,the effectiveness of such work has been verified and compared with four different work in the literature。

关键词： multi antennas-multiband wireless PAPR Haar-DWT power reallocation ACLR EVM