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PublicationMagnetic induction tomography for brain tissue imaging based on conductivity distribution for parkinson’s disease diagnosis( 2023-10)Parkinson's disease is a prevalent neurodegenerative complication defined by the accumulation of alpha synuclein lewy bodies in the brain. Misdiagnosis results widespread of Parkinson’s disease because clinical diagnosis is challenging, underlining a need of a better detection technique, such as non-invasive magnetic induction tomography (MIT) technique. Non-invasive techniques for biological tissues imaging are becoming popular in biomedical engineering field. Therefore, MIT technology as a non-invasive technique has been encouraged in a medical field due to its advancement of technology in diagnosing diseases. The measurement parameters in MIT are passive electromagnetic properties (conductivity, permittivity, permeability) for biological tissue and the most dominant parameter in MIT is conductivity properties. It is uses a phase shift between a primary magnetic field and an induced field caused by a target object's conductivity. As a function of conductivity, the phase shift between the applied and secondary fields is expressed. Thus, the phase shift can be used to characterize the conductivity of a target object. The phase shift between the excitation and induced magnetic fields (EMF and IMF) reflects the change in conductivity in biological tissues. This paper focuses on the virtual simulation by using COMSOL Multi-physics for the design and development of MIT system that emphasizes on single channel magnetic induction tomography for biological tissue (bran tissue) imaging based on conductivity distribution for Parkinson’s disease diagnosis. The develop system employs the use of excitation coils to induce an electromagnetic field (e.m.f) in the brain tissue, which is then measured at the receiving side by sensors. The proposed system is capable of indicating Parkinson’s disease based on conductivity distribution. This method provides the valuable information of the brain abnormality based on differences of conductivities of normal brain and Parkinson’s disease brain tissues.
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PublicationI-V characteristics of polycrystalline CAZTSe heterojunction solar cells at different ag content and annealing temperatures( 2013-10)Since the polycrystalline (Cu₁-xAgx)₂ZnSnSe₄ (CAZTSe) demonstrated good optical absorption performance in the visible region, the focus of the present study is to grow the polycrystalline (Cu₁-xAgx)₂ZnSnSe₄ thin films deposited by thermal evaporation method on silicon substrates with 800 nm thickness and 0.53 nm/sec deposition rate as a function of Ag content (0.0,0.1,0.2) and annealing temperature at 373 K, 473 K. From I-V measurements of Al/n-CdS/p-CAZTSe/n-Si(111)/Al heterojunction solar cells under dark and illumination conditions, we observed that the forward bias current changes roughly exponentially with bias voltage and the ideality factor and saturation current dependence on both x content and different temperatures (Ta).
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PublicationHydrothermal growth zinc oxide nanorods for pH sensor application( 2023-10)The aim of this work is to apply synthesized zinc oxide (ZnO) Nanorods using hydrothermal (HTL) growth technique for pH sensor application. The highly crystallite of ZnO Nanorods was obtained by anneal the growth ZnO Nanorods in furnace at 200°C for 2 hours. Besides that, XRD analysis shows the produced ZnO Nanorods belonged to the (002) plane. Furthermore, Scanning Electron Microscope (SEM) images confirm that the ZnO Nanorods with hexagonal-faceted structural were successfully produced by HTL growth technique. In addition, Ultraviolet–visible (UV-Vis) spectrophotometer analysis shows that the synthesized ZnO belongs to the wide band gap semiconductor material. The growing ZnO Nanorods were then subjected to electrical measurement with various pH levels. The outcome demonstrates that the current rises as the solution changes from acidic to alkaline. Overall, our study shows a relationship between the electrical as well as the structural characteristics of ZnO Nanorods at various pH levels.
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PublicationInvestigate the physical properties and transmitted sunlight of PVC-PMMA- ZnO nanocomposite films( 2023-10)Pure blend (PVC0.3g +PMMA 0.2g) and blend/ZnO nanocomposite films with different amounts were created using the solution casting technique. Different amounts of zinc oxide from (0.001, 0.002, 0.003, 0.004, and 0.005)g were investigated and added to blend polymer with a fixed amount (0.5) g of PVC/PMMA in 15ml tetrahydrofuran (THF). The XRD results demonstrated the amorphous structure of the admixture film and the hexagonal crystal structure of ZnONPs. The ZnONPs in the film were also atomically dispersed resulting in the incorporation of the ZnONPs peaks within the polymer matrix. FESEM image of the mixture and ZnO revealing small white spots scattered on the surface of the mixture with some agglomerates. FTIR spectroscopy data showed no chemical interaction between the polymer blend and ZnONPs. The increasing amounts of ZnONPs improved the absorbance, absorption coefficient, and extinction coefficient of the blend polymer. The blended polymer's permeability and energy gap decreased from 4.48eV to 3.91eV with the increase in the number of ZnONPs in the nanocomposites. The transmitted sunlight intensity was measured through the blended pure polymer films and the blended nanocomposites/ZnO nanocomposites. At the beginning of September 2021, the intensity of transmitted sunlight was measured in Baghdad for a period of 7 days. As can be observed, almost all films have the same ratio of the intensity of transmitted radiation to the intensity of sunlight for all hours and days.
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PublicationFabrication, characterization and release profile of aloe vera extracts-PVA composite electrospun nanofiber( 2023-10)Aloe vera is a well-known remedy that carries many beneficial health effects such as painkiller, anti-inflammatory, promote skin growth and repair. The combination of bioactive natural product of aloe vera as a drug model and polyvinyl alcohol (PVA) as the base material or carrier in the electrospinning process were studied. Smooth straight and continues electrospun fibers were collected with the Field Effect Scanning Electron Microscope (FESEM) images show no formation of bead (defect signed) in the electrospun membrane when the concentration was set at 10% w/w of PVA nanofibre. The morphological structure of the electrospun membranes shows a smooth and longitudinal fiber when aloe vera is mixed with the PVA polymer with percentage ratio of aloe vera over PVA is less than 25%. The Fourier Transform Infrared Spectroscopy (FTIR) shows no reaction between PVA and aloe vera by not showing peaks other than the initial materials. The Differential Scanning Calorimetry (DSC) proves the presence of aloin indicating the presence of aloe vera in nanofiber. The release profile of the electrospun aloe vera in PVA shows a higher initial burst release at the 50% and 70% concentration levels indicating very little control of the release or none at all. These results show the potential of aloe vera – PVA electrospun nanofibers membrane as a promising material for wound dressing and topical drug delivery.
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PublicationThe dependence of saturation velocity on temperature, inversion charge and electric field in a nanoscale MOSFET( 2010-01)The intrinsic velocity is shown to be the ultimate limit to the saturation velocity in a very high electric field. The unidirectional intrinsic velocity arises from the fact that randomly oriented velocity vectors in zero electric field are streamlined and become unidirectional giving the ultimate drift velocity that is limited by the collision-free (ballistic) intrinsic velocity. In the nondegenerate regime, the intrinsic velocity is the thermal velocity that is a function of temperature and does not sensitively depend on the carrier concentration. In the degenerate regime, the intrinsic velocity is the Fermi velocity that is a function of carrier concentration and independent of temperature. The presence of a quantum emission lowers the saturation velocity. The drain carrier velocity is revealed to be smaller than the saturation velocity due to the presence of the finite electric field at the drain of a MOSFET. The popular channel pinchoff assumption is revealed not to be valid for either a long or short channel. Channel conduction beyond pinchoff enhances due to increase in the drain velocity as a result of enhanced drain electric field as drain voltage is increased, giving a realistic description of the channel length modulation without using any artificial parameters. The velocity so obtained is considered in modeling the current voltage characteristics of a MOSFET channel in the inversion regime and excellent agreement is obtained with experimental results on an 80-nm channel.
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PublicationTransport phenomena of circular particles and fibers rotating drum( 2010-01)Several processing techniques have been proposed for the fabrication of functionally graded materials (FGMs), whose composition and microstructure, i.e., the chemical and physical properties vary in the specific direction. The mechanical property of FGMs is affected by dispersed particle size, its volume fraction, and particle orientation. In order to clarify its property, it is important to disclose the particle motion during the fabrication process. In this study, circular particles and fiber motion during fabrication of Functionally Graded Materials is studied using the cold model centrifugal casting. Consideration is given to the timewise variation of the radial circular-disk and fiber motion in the axially rotating cold water drum. The velocity measurement is carried out by means of the Particles Tracking Velocimetry (PTV) method and the measured value is compared with that estimated by the theoretical prediction. It is found that (i) as the disk moves toward the rotating wall, its motion is perpendicular to the wall, (ii) the measured velocity is in good agreement with compared with the theoretical one (BBO equation), (iii) in contrast, translation and rotation of the fiber occur in the interior region and each fiber is oriented in the several directions, and (iv) these motions of the fiber are suppressed and one side of the fiber tips is attracted toward the drum wall as time progresses.
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PublicationFormation and thermal properties of Fe-based BMG's with Y or Gd addition( 2010-01)In the present work, the glass formation of Fe ₅₀-ₓ Cr ₁₅ Mo ₁₄ C ₁₅ B ₆ M x (x = 0,2 and M = Y,Gd) alloys has been investigated. Wedge shaped bulk samples, with thickness from 2 mm up to 5 mm, were prepared by copper mold casting technique. Ribbons of the same compositions, with 30 µm in thickness, were produced by melt-spinning technique. Thermal and structural properties were measured using High Temperature Differential Scanning Calorimetry and X-ray diffraction, respectively. The microstructure has been observed by Scanning Electron Microscopy and chemical composition was checked by Energy Dispersion Spectroscopy. In the case of ribbons, fully amorphous phase was observed for all compositions. Copper mold casting technique leads to a fully amorphous structure for bulk samples up to 2 mm only for composition containing Y or Gd. Such elements can act as oxygen scavengers, avoiding heterogeneous nucleation. The role of Y and Gd on glass formation is also discussed on the basis of the melting behavior.
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PublicationInSb semiconductor-metal hybrid structure (SMH) as a magnetic sensor prepared by flash evaporation( 2010-01)n-type indium-Au van der Pauw (vdP) shape hybrid macro-structure were successfully fabricated by flash evaporation technique. The elemental composition of the prepared films was confirmed by energy dispersive X-ray spectroscopy microanalysis (EDX). The morphologies and crystal structures of the films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The magnetoresistance of the prepared hybrid structure was measured at room temperature and 100mA current ans a variable magnetic filed (0-8kG). The effect of sensor geometry on magnetoresistance was studied.
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PublicationSimulation model of multi-junction InxGa1-xN solar cells( 2010-01)In this model we investigate theoretically the characteristics of multi junction InxGa1-xN series-connected solar cells under air mass 1.5 global irradiance spectrum using Matlab program. The doping levels of p-type and n-type were 5x10^18 cm^-3 and 1x10&18 cm^-3 respectively. The efficiency is found to be varied from 18.01% for single junction to 42.55% for five junctions. The enhancement in Voc was observed from the lower values of total thickness.
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Uda Hashim
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