Pusat Pengajian Sains Fizik - Tesis

Browse

Now showing 1 - 20 of 60

Sifat-Sifat Optik Filem Nipis Germanium Amorfus Tersejat
(1993-03)
Saw Kim Guan
Filem nipis germanium amorfus dimendapkan pada kaca borosilikat melalui penyejatan vakum. Kesan ketebalan filem ke atas jurang optik, Eg, filem a-Ge yang dimendapkan pada suhu bilik dengan kadar cepat dan lambat dikaji dan dibandingkan.
Fabrication And Characterization Of Normoxic Polymer Gel Dosimeter By Using Raman Spectroscopy At Low X-Ray Energies
(2012-12)
Aifa Aflrah Binti Rozlan
Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. Two types of normoxic polymer gel dosimeters were fabricated, which is PHEAG (polyhydroxyethyl acrylate) and PHEMAG (polyhydroxyethyl methacrylate) gel dosimeters. These polymer were fabricated by using gelatin, N' N-methylene-bisacrylamide (BIS), ascorbic acid (AA), deionized water and 2-hydroxyethyl acrylate (HEA) for PHEAG and 2-hydroxyethyl methacrylate for PHEMAG. The ability of AA to bind oxygen in the gel solution was investigated by using an oxygen dissolve meter. The concentrations of AA used are 5, 10, 15 and 35 mM and each concentration was applied to each batch of PHEAG and PHEMAG. The sensitivity of PHEAG and PHEMAG towards low X-ray energy was investigated. The structural changes of the monomeric components in PHEAG and PHEMAG after irradiation were analyzed using Raman spectroscopy.
Fabrication And Characterization Of Tio2 - Pvp Nanofibre Using Electrospinning Method For Hydrogen Gas Sensing
(2016-08)
Abed, Nabeel Zabar
In this project, anatase phase titanium dioxide (TiO2) nanofibers (NFs) are successfully fabricated using the homemade electrospinning (ES) method. This study aims to fabricate uniform and high quality anatase TiO2/polyvinylpyrrolidone (PVP) NFs on the glass substrate. A number of parameters were studied for the development of best form of nanofibers; the most suitable/optimised parameters for the fabrication of hydrogen gas sensor device were found at room temperature. Xray diffraction (XRD) patterns show sharp and well-defined peaks identified as anatase phase. Field emission scanning electron microscope (FESEM) images revealing the formation of nanofibers are investigated. Surface topography observations by atom force microscopy (AFM) indicate that the roughness is improved by effect of the parameters selected and optical properties were measured using ultraviolet-visible-near infrared (UV-Vis-NIR.) spectrometer.
Reduction Of Backscattered Radiation For X-Ray Image Quality Enhancement
(2016-12)
Qaed Naji, Abdullah Taher
This study mainly aims to reduce backscattered radiation inside an X-ray room. The characteristics of X-ray attenuation in several materials such as lead, copper, iron steel, aluminium, and concrete have been investigated under different exposure parameters to measure their abilities to attenuate incident X-ray and to reduce backscattered X-ray. Lead and Iron presented good attenuation values for incident X-ray at radiographic diagnosis energy range (50 -110 kVp), whereas iron and aluminium reflected the least amount of backscattered radiation dose. A number of anti-scatter grids have been designed and fabricated from iron steel and aluminium, because of their relatively better abilities to reduce backscattered radiation compared to other materials.
Growth Of Zno Nanorods On Wire Via Sonochemistry Method For Glucose Sensing
(2017-02)
Rayathulhan, Ruzaina
There has been much research on growth of ZnO nanorods on vanous substrates, and various growth methods. Sonochemical method is a well-known method for growing nanorods. Metal wire is a suitable substrate for the growth of ZnO nanorods as it can then be used as sensor electrode for sensing application. However there has not been any report on growth of ZnO nanorods on metal wire directly using sonochemical method. ZnO nanorods were directly grown on four different wires (silver (Ag), nickel (Ni), copper (Cu), and tungsten (W)) through sonochemical method and the best sample was chosen as electrode and tested for glucose sensing. Zinc nitrate hexahydrate and hexamethylenetetramine (HMT) were used as precursors for the growth of ZnO nanorods. The optimum condition for the growth of ZnO nanorods were determined by varying precursor molarity, sonication time and molar ratio of precursor solution.
Delineation Of Seulimeum Fault System And Identification Of Geothermal Signatures Using Ground Magnetic And 2-D Resistivity Imaging Methods
(2017-02)
February 2017
Ground magnetic and 2-D resistivity imaging method are widely used in geophysical exploration for subsurface identification to study the earth rheology such as fault process based on the geophysical parameter. Ground magnetic and 2-D resistivity imaging surveys were conducted to investigate the trend of Seulimeum fault system and the signature of potential geothermal surface manifestation resulting from the fault. Four different sites, namely Krueng Raya, Iejue, Lamtamot, and Tangse were chosen as study area for Seulimeum fault study while two sites; lejue and Ie-Seu 'Urn were chosen as case study areas in identifying the geothermal signatures. Ground magnetic method was performed using proton magnetometer while the 2-D resistivity imaging survey was done using ABEM Terrameter with Pole-dipole array. The magnetic residual contour map in Krueng Raya locality shows the dislocation from northwest to southeast (NW-SE) direction with contrast of high and low magnetic residual ranging from -150 nT to 300 nT which interpreted as the geological fault. In Iejue site the result shows the contrast of magnetic residual between -150 nT to 300 nT which indicate as geological fault continuous from Krueng Raya.
The Biostimulation Of Low Level Laser Irradiation On Blood Parameters: Ex Vivo
(2017-07)
Al Musawi, Mustafa Salih Ali
Various low-level laser wavelengths have been used for a variety of clinical applications because of their ability to modulate blood rheology and improve microcirculation. The response of human blood to low-level laser irradiation (LLLI) provides important information about the interactions of laser light with living tissues. This study was designed to investigate whether in vitro LLLI changes the erythrocyte sedimentation rate (ESR) and other blood indices of whole blood. Blood samples were collected by venipuncture into ethylenediaminetetraacetic acid (EDTA)-containing tubes. Each sample was divided into two equal aliquots as a control (non-irradiated) and irradiated samples. The irradiated sample was subjected to LLLI doses of 36, 54, 72 and 90 J/cm2 at wavelengths of 405, 589 and 780 nm.
Enhanced Led Thermal Conductivity Of Filled Epoxy Resin Containing Multimodal Distribution Of Ceramic Particles And Graphene Sheets
(2018-07)
Permal, Anithambigai
Present work was designed to investigate the class of possible materials to be compounded as thermally conductive composite as well as to be catered as thermal interface material (TIM) for an improved thermal performance of a high power light emitting diode (LED) headlamp, a product of OSRAM Opto Semiconductors. This research was earned out to produce a closely packed ceramic and graphene filled hybrid epoxy composite. The work was earned out by understanding the physical and chemical behaviour of aluminium nitride (AIN), boron nitride (BN) and aluminium oxide (AI2O3). Also a comparison of compatibility between two commercial epoxy matrices has been presented in this work. The thermal conductivity of unimodal AIN, bimodal A1N/BN and bimodal AI2O3 were investigated.
Simulation And Performance Studies Of Thermally Efficient Light Emitting Diodes Drivers
(2018-09)
Mohd Supian, Norazlina
The thermal behaviour of an electronic package is often characterized by evaluating the junction temperature and thermal resistance at the junction of a single or multiple heat source to ambient. In the case of IC LED drivers, the heat source within the device is either single or multiple due to presence of many integrated component such as transistor, internal resistor, etc on a single die. Hence the evaluation of IC drivers with single or multiple heat sources is absolutely necessary for imparting suitable thermal management within the device. In this study, thermal transient measurement method and computational fluid dynamics (CFD) simulations have been used to measure thermal resistance and junction temperature.
Assessment Of Uranium, Lead, Cadmium And Iron In Maternal And Umbilical Cord Blood Samples In Iraq
(2019-03)
Hasan Rhaif Al-Sahlanee, Mayyadah
The assay of blood samples is a preferred method for monitoring the internal exposure of radiological and toxicological contaminants in human body. The objectives of this study were to evaluate the status of uranium (U) radioactivity and selected heavy metals such as lead (Pb), cadmium (Cd) and iron (Fe) in maternal and umbilical cord blood samples for normal and deformed infants in Iraq, and the influence of these elements to the foetus development and to identify predictors of maternal exposure. Additionally, to assess the interactions between these elements in the maternal and umbilical cord blood samples. A cross-sectional study was conducted in three public hospitals (Al-Yarmouk Teaching Hospital, Al-Basrah Maternity and Children Hospital and Al-Shatra Maternity Hospital).
The Growth Of GaN-Based Low Dimensional Structures By CVD Using Platinum And Palladium Catalysts
(2019-03)
Tan, Lay Kim
This research project presents the growth of low dimensional GaN structures employing monometallic catalyst (Pt and Pd) and bimetallic catalysts (Pd/Pt) by means of chemical vapor deposition based on vapor-liquid-solid mechanism.
Development Of A Digital Camera-Based Spectrometer For Led Spectrum Analysis
(2019-04)
Teo, Choon Kiat
Charge-Coupled Device (CCD) spectrometer instrument has been widely used in many applications such as photonics research, opto-semiconductor test and measurement, colour imaging science, and many more. The great function of this instrument is the capability of providing essential information about the properties of light which sensed by the instrument CCD sensor.
Study Of Biostimulation Effect On Normal And Anaemic Human Blood Cell Irradiated By 589 nm And 532 nm Laser
(2019-04)
Fauzi, Nabihah
Laser (light amplification by stimulated emission of radiation) is a monochromatic light. It has been widely used in various fields including in the field of medicine. Application of Low Level Laser (LLL) at low output power (1-500 mW) has been proven to have therapeutic or biostimulation effects on biological tissues or cells. Widespread applications of LLL in medical practices including blood irradiation have resulted in the investigations on the bio-stimulation effects on irradiated human red blood cell (RBC). In this study, full blood count was measured on normal and anaemic human blood, the morphology of RBC were compared and the adenosine 5’-triphosphate (ATP) values were analysed.
Local Land Subsidence Analysisi In Penang Island (Malaysia) Based On Insar Maps
(2021-11)
Gao Guosheng
Penang Island is an important economic centre in Malaysia that has experienced land subsidence in recent years. In this study, the PS-InSAR and SBAS-InSAR techniques are used to monitor land subsidence of Penang Island based on Sentinel-1 SAR radar images in both ascending and descending tracks.
Characterization Of 2-Dimensional Electrical Resistivity Tomography, Geotechnical And Hydraulic Conductivity Analysis In The Granitic Residual Soil
(2021-12)
Oladunjoye Peter Olabode
This research aims to characterise 2-D Electrical Resistivity Tomography (ERT) models for changes in soil saturation, analyse geotechnical properties of residual soil for validation of ERT models and develop a relationship between soil resistivity and Hydraulic Conductivity (HC) for lithological characterisation for slope instability assessment.
Study Of Titanium Dioxide Nanotubes And Nanoparticles For Ultraviolet Photodetection Application
(2021-12)
Low Kai Ti
Fabrication And Characterization Of Black Silicon For Heterojunction Solar Cells
(2022-01)
Abdulkadir, Auwal
Black silicon (b-Si) is a promising technology that reduces broadband reflection within 300-1100 nm wavelength region and improves light absorption in crystalline silicon (c-Si). B-Si consists of a surface with random nanowires or a combination of nanowires and microtextures (hybrid textures) which leads to a refractive index grading effect at the air/c-Si interface. In this work, electroless metal-assisted chemical etching (MACE) is used to fabricate b-Si. One-step MACE, two-step MACE and hybrid microtextures/nanotextures investigating different effects such as etching time, etchants concentration, silver nanoparticles (Ag NPs) layer thickness towards surface morphological and optical properties (within 300-1100 nm wavelength region) of the b-Si are carried out. Two step MACE involve shorter AgNO3:HF dip time. The hybrid texturing involves prior etching in NaOH to produce pyramids. For one-step MACE, nanowires with an average length of ~2.9 μm and an average diameter of ~120 nm are demonstrated. Weighted average reflection (WAR) of 6.0% has been realized. For two-step MACE, nanowires with an average length of 577 nm and diameter of ~200 nm are produced with WAR of ~5.5%.
Zno Based Extended Gate Field Effect Transistor (EGFET) Dosimeter Fabrication With Dopant Elements Of Pb, Al And Bi For X-Ray In Diagnostic Energy Range
(2022-02)
Ahmed Ali, Amal Mohamed
Real time dosimetry is a major challenge in medical, industrial and education fields. One promising candidate for dosimetry is the metal oxide semiconductor fieldeffect transistor (MOSFET) dosimeter. A new design of the MOSFET dosimeter is being developed in a different study to measure the dose delivered to the tissue layers. This thesis will discuss the development of a new type of radiation detector based on the characteristics of different metal oxide materials, and a new model of radiation detector, known as extended gate field-effect transistor (EGFET) and the optimization of the operating conditions.
Application Of 2-D Resistivity And Self-Potential Methods In Delineating Water Flow
(2022-02)
Mahmud, Nazirah
Water flow is essential for engineers when constructing any form of structure. A vital factor to consider is water flows through the soil can impact the engineering and environmental aspects. In recent years, the self-potential (SP) method was rarely found in dealing with the water flow issue. In this research, 2-D resistivity and SP methods have been chosen to detect the potential area of water flow. Geophysical methods are non-standalone methods as the data might be affected by the surrounding environment. The integrations of geophysical and geotechnical methods are performed to increase the understanding of subsurface features and water flow. 2-D resistivity can identify the position of conductive materials in the subsurface. SP measures the natural potential of the Earth, such as electrokinetic potential, which arises when water flows through the subsurface. The auger samples and borehole data were used to support the geophysical interpretation. As a result, the potential area of water was identified at low resistivity area (< 200 Ωm) and low SP value which indicate as recharge zone.
Investigating Random Laser From Aluminium-doped Zinc Oxide Nanorods
(2022-04)
Ali,Abdullah Taha
In this research, random lasing (RL) properties are investigated from Aluminium-doped Zinc oxide (AZO) nanorods (NRs) prepared by chemical bath deposition (CBD) method, then capped with silicon dioxide (SiO2) layer by radio frequency sputtering technique. The integration of the two approaches aims to improve ultraviolet RL emission from AZO NRs whilst enabling lasing tunability by adjusting doping parameters. Therefore, this work is divided into three parts. The first part is to determine the optimal growth conditions for AZO NRs. The second part is to identify RL emission properties from AZO NRs. The third part focuses on investigating the effect of having SiO2 capping layer on ZnO NRs and AZO NRs by varying SiO2 thicknesses. The structural, morphological, optical and electrical properties of the samples were also investigated for clarity. Increasing Al concentration during the CBD process led to a decrease in the growth rate and showed an increase in the size of NRs. This becomes a problem in identifying the RL properties that is due to doping since there is significant changes in morphology or structure. A different attempt in increasing the Al doping percentage was done by varying the CBD temperature at a fixed concentration of 5mM, this concentration, which was determined to be the maximum concentration that preserves the morphology of AZO NRs, demonstrated to solve this problem. The sample with the highest doping (1.72 at.%) exhibited the lowest lasing threshold of 0.192 mW with spectral width less than 0.08 nm.

Browse

Browsing Pusat Pengajian Sains Fizik - Tesis by Issue Date

Results Per Page

Sort Options