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Insoluble additives for enhancing a blood-like liquid flow in micro-channels

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Journal of Hydrodynamics 2017年第1期29卷 144-153页

作者： Hayder A.Abdulbari Fiona Ling Wang Ming Wafaa k.mahmood Center of Excellence for Advanced Research in Fluid Flow Universiti Malaysia PahangGambang 26300KuantanPahangMalaysia Faculty of Chemical Engineering and Natural Resources University Malaysia PahangLebuhraya Tun Razak 26300 KuantanPahangMalaysia

This study introduces an approach for flow enhancement in the bloodstream using insoluble additives as non-degradable drag reducing agents that can replace the polymeric soluble additives. An open micro-channel liquid flow system with three different channel sizes was assembled and used to test the drag reduction performances of the solutions investigated. Three different nano- powders （with five different addition concentrations） were investigated and used to form solutions of artificial blood with blood-like rheological properties. The experimental results showed that the optimum drag reduction performance was achieved using bismuth III oxides （65%） for a 200 ppm concentration solution flowing through a 100 μm channel, while titanium IV oxides and fumed silica achieved 57 and 55% drag reduction for a 200 ppm concentration solution flowing in a 50 ktm channel, respectively.

关键词： Microchannels pressure drop drag reduction nano-powder additives

Phase transformation from cubic ZnS to hexagonal ZnO by thermal annealing

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Journal of Semiconductors 2015年第3期36卷 19-22页

作者： k.mahmood M.Asghar N.Amin Adnan Ali Department of Physics GC University Faisalabad Department of Physics The Islamia University of Bahawalpur

We have investigated the mechanism of phase transformation from ZnS to hexagonal ZnO by high- temperature thermal annealing. The ZnS thin films were grown on Si （001） substrate by thermal evaporation system using ZnS powder as source material. The grown films were annealed at different temperatures and characterized by X-ray diffraction （XRD）, photoluminescence （PL）, four-point probe, scanning electron microscope （SEM） and energy dispersive X-ray diffraction （EDX）. The results demonstrated that as-deposited ZnS film has mixed phases but high-temperature annealing leads to transition from ZnS to ZnO. The observed result can be explained as a two- step process：（1） high-energy O atoms replaced S atoms in lattice during annealing process, and （2） S atoms diffused into substrate and/or diffused out of the sample. The dissociation energy of ZnS calculated from the Arrhenius plot of 1000/T versus log （resistivity） was found to be 3.1 eV. PL spectra of as-grown sample exhibits a characteristic green emission at 2.4 eV of ZnS but annealed samples consist of band-to-band and defect emission of ZnO at 3.29 eV and 2.5 eV respectively. SEM and EDX measurements were additionally performed to strengthen the argument.

关键词： ZnS phase transformation EDX XRD PL

Theoretical investigation of sulfur defects on structural, electronic,and elastic properties of ZnSe semiconductor

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Chinese Physics B 2015年第7期24卷 365-370页

作者： Muhammad Zafar Shabbir Ahmed M.Shakil M.A.Choudhary k.mahmood Simulation Laboratory Department of PhysicsThe Islamia University of Bahawalpur 63100Pakistan Department of Physics GC UniversityFaisalabad 68000Pakistan

The structural, electronic, and elastic properties of ZnSe1-xSx for the zinc blende structures have been studied by using the density functional theory. The calculations were performed using the plane wave pseudopotential method, as implemented in Quantum ESPRESSO. The exchange-correlation potential is treated with the local density approximation pz-LDA for these properties. Moreover, LDA＋U approximation is employed to treat the ＂d＂ orbital electrons properly. A comparative study of the band gap calculated within both LDA and LDA＋U schemes is presented. The analysis of results show considerable improvement in the calculation of band gap. The inclusion of compositional disorder increases the values of all elastic constants. In this study, it is found that elastic constants C11, C12, and C44 are mainly influenced by the compositional disorder. The obtained results are in good agreement with literature.

关键词： first principles calculations density functional theory II–VI semiconductors electronic and elastic properties

Characterization of deep acceptor level in as-grown ZnO thin film by molecular beam epitaxy

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Chinese Physics B 2014年第9期23卷 364-368页

作者： M.Asghar k.mahmood M.A.Hasan I.T.Ferguson R.Tsu M.Willander Department of Physics The Islamia University of Bahawalpur Department of Electrical and Computer Engineering University of North Carolina Charlotte Department of Science and Technology Linkping University Norrkping

We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy （MBE）, The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-voltage （l-V） measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 ± 0.03 eV and capture cross-section of 8,57 ×10^-18 cm^2. Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy （SIMS） of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO,

关键词： ZnO secondary ion mass spectroscopy photoluminescence Raman spectroscopy

Enhancement of phosphors-solubility in ZnO by thermal annealing

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Journal of Semiconductors 2015年第12期36卷 30-33页

作者： k.mahmood N.Amin A.Ali M.Ajaz un Nabi M.Imran Arshad M.Zafar M.Asghar Department of Physics GC University Faisalabad Department of Physics Islamia University of Bahawalpur

We have demonstrated the effect of annealing temperature on the diffusion density of phosphors in zinc oxide. The P-dopant P430 was sprayed on ZnO pellets and annealed at different temperatures from 500 to 1000 ℃ with a step of 100 ℃ for one hour using a programmable furnace. The concentration of P was controlled by varying the annealing temperature and the maximum solubility of P （3% At） was achieved at annealing 800 ℃ determined by energy dispersive X-ray diffraction （EDX） measurements. X-ray diffraction （XRD） confirmed the hexagonal structure of ZnO and showed that the growth direction was along the c-axis. We observed a maximum up shift in the （002） plane at an annealing temperature of 800 ℃, suggesting that P atoms replaced Zn atoms in the structure which results in the reduction of the lattice constant. Room temperature photoluminescence （PL） spectrum consists of a peak at 3.28 eV and related to band edge emission, but samples annealed at 800 and 900 ℃ have an additional donor acceptor pair peak at 3.2 eV. Hall effect measurements confirmed the p-type conductivity of the sample annealed at 800 ℃.

关键词： ZnO P-dopant EDX XRD PL

Quintessence anisotropic stellar models in quadratic and Born-Infeld modified teleparallel Rastall gravity

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Chinese Physics B 2024年第3期33卷 179-189页

作者： Allah Ditta 夏铁成 Irfan mahmood Asif mahmood Department of Mathematics Shanghai University and Newtouch Center for Mathematics of Shanghai UniversityShanghai 200444China Centre for High Energy Physics University of the PunjabLahorePakistan College of Engineering Chemical Engineering DepartmentKing Saud University RiyadhSaudi Arabia

This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of *** achieve this goal,the krori and Barua arrangement for spherically symmetric components of the line element is *** explore the field equations by selecting appropriate off-diagonal tetrad ***-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are *** Born-Infeld gravity was the first modified teleparallel gravity to discuss *** use the linear equation of state pr=ξρto separate the quintessence *** obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar *** use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.

关键词： anisotropic spheres quintessence field modified Rastall teleparallel gravity equation of state(EoS) f(T)gravity

Olive Leaf Disease Detection via Wavelet Transform and Feature Fusion of Pre-Trained Deep Learning Models

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Computers, Materials & Continua 2024年第3期78卷 3431-3448页

作者： mahmood A.mahmood khalaf Alsalem Department of Information Systems College of Computer and Information SciencesJouf UniversitySakakahKingdom of Saudi Arabia Department of Information Systems and Technology Faculty of Graduate Studies and ResearchCairo UniversityGizaEgypt

Olive trees are susceptible to a variety of diseases that can cause significant crop damage and economic *** detection of these diseases is essential for effective *** propose a novel transformed wavelet,feature-fused,pre-trained deep learning model for detecting olive leaf *** proposed model combines wavelet transforms with pre-trained deep-learning models to extract discriminative features from olive leaf *** model has four main phases:preprocessing using data augmentation,three-level wavelet transformation,learning using pre-trained deep learning models,and a fused deep learning *** the preprocessing phase,the image dataset is augmented using techniques such as resizing,rescaling,flipping,rotation,zooming,and *** wavelet transformation,the augmented images are decomposed into three frequency *** pre-trained deep learning models,EfficientNet-B7,DenseNet-201,and ResNet-152-V2,are used in the learning *** models were trained using the approximate images of the third-level sub-band of the wavelet *** the fused phase,the fused model consists of a merge layer,three dense layers,and two dropout *** proposed model was evaluated using a dataset of images of healthy and infected olive *** achieved an accuracy of 99.72%in the diagnosis of olive leaf diseases,which exceeds the accuracy of other methods reported in the *** finding suggests that our proposed method is a promising tool for the early detection of olive leaf diseases.

关键词： Olive leaf diseases wavelet transform deep learning feature fusion

Location of Disaster Management Bases Using Spatial Analysis

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 1-29页

作者： Hadi Nayyeri Sahar Zandi mahmood Souri Department of Geomorphology Faculty of Natural ResourceUniversity of KurdistanSanandajKurdistanIran Department of Geography Sciences Kharazmi UniversityTehranIran Red Crescent Society of the Islamic Republic Employee of Iran HamedanIran

Pre-crisis management involves the optimal selection of relief and rescue centers to minimize *** is particularly vulnerable due to its location on the Alpine-Himalaya seismic belt,resulting in an average death rate six times higher than the global average during ***,selecting appropriate relief and rescue centers is crucial to Iran’s disaster *** selecting the placement of rescue centers,accessibility and the appropriateness of the land should be taken into account as well as the distance from high-risk *** location of these centers does not require any particular *** address this issue,a study was conducted utilizing GIS,artificial neural networks,fuzzy logic,and mathematical models to determine the optimal placement based on 12 indicators within two clusters:natural and *** examine the information layers of the initial stage,a spatial data repository concerning the variables impacting the placement of these centers was established using *** functions and algorithms such as Fuzzy Logic in IDRISI,TOPSIS,and VIkOR software,the layers were assessed for weightage before being *** study’s analysis of the models used revealed that the positioning priority limits of the areas differed across all four ***,the areas with high desirability varied to a greater extent:the fuzzy model varied by 9.3%,neural network by 12.4%,VIkOR by 4.5%,and TOPSIS by 16.2%.The variance in results can be attributed to the differing levels of risk acceptance and non-acceptance in each ***,the study yielded other significant findings such as the correlation between study area size and model ***,smaller study areas exhibited higher model *** research also demonstrated that both fuzzy and VIkOR models achieved greater *** a result,employing these models in crisis management planning,particularly in pre-crisis management for identifying rescue center lo

关键词： Crisis management GIS earthquake risk site selection

Mesenchymal stem cell-derived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration

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Neural Regeneration Research 2024年第1期19卷 49-54页

作者： Ye Xiong Asim mahmood Michael Chopp Department of Neurosurgery Henry Ford HospitalDetroitMIUSA Department of Neurology Henry Ford HospitalDetroitMIUSA Department of Physics Oakland UniversityRochesterMIUSA

Traumatic brain injury is a serious and complex neurological condition that affects millions of people *** significant advancements in the field of medicine,effective treatments for traumatic brain injury remain ***,extracellular vesicles released from mesenchymal stem/stromal cells have emerged as a promising novel therapy for traumatic brain *** vesicles are small membrane-bound vesicles that are naturally released by cells,including those in the brain,and can be engineered to contain therapeutic cargo,such as anti-inflammatory molecules,growth factors,and *** administered intravenously,extra cellular vesicles can cross the blood-brain barrier and deliver their cargos to the site of injury,where they can be taken up by recipient cells and modulate the inflammatory response,promote neuroregeneration,and improve functional *** preclinical studies,extracellular vesicle-based therapies have shown promising results in promoting recove ry after traumatic brain injury,including reducing neuronal damage,improving cognitive function,and enhancing motor *** further research is needed to establish the safety and efficacy of extra cellular vesicle-based therapies in humans,extra cellular vesicles represent a promising novel approach for the treatment of traumatic brain *** this review,we summarize mesenchymal ste m/stromal cell-de rived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration and brainderived extracellular vesicles as potential biofluid biomarkers in small and large animal models of traumatic brain injury.

关键词： biomarkers extracellular vesicles functional outcome mesenchymal stem/stromal cells neuroinflammation neuroplasticity neuroprotection traumatic brain injury