Pusat Pengajian Sains Fizik - Tesis

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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.
Application Of Machine Learning And Global Optimization On An Electromagnetic Scattering Problem.
(2023-01)
Thong, Ying Li
Assessment Of Airborne Particulate Matter And Radioactivity At Qassim, Saudi Arabia
(2023-09)
O, Alnagran Hamed Mohammed
Epidemiological and toxicological research has shown a close connection between particulate matter (PM) with respiratory and cardiovascular disorders. Thus, PM in the air we breathe is detrimental to human health. Numerous nations have conducted in-depth study on the problem of PM and related health and environmental issues. Therefore, this study describes the radioactivity, physical and chemical properties of PM in Qassim. This research focuses on radioactive particle, which in turn impact the environmental comportments of the related radionuclides. PM of size less than 2.5 microns in aerodynamic diameter (PM2.5) and PM less than 10 microns in aerodynamic diameter (PM10) concentrations have been measured during the period of July 2020–June 2021 in the central urban and rural areas of Qassim. In urban Qassim, the average PM concentration were 33.16 μg/m3 and 155.38 μg/m3 for PM2.5 and PM10, respectively. In rural Qassim, the PM concentrations were 23.03 μg/m3 and 93.57 μg/m3, respectively. A total of 18 elements were determined and identified, and their concentrations in (mg/kg) were compared to literature. Natural radioactivity levels of 226Ra, 232Th, and 40K in 276 samples were evaluated using sodium iodide (NaI) detector. Ra-226 activity concentration ranged from 10.01 to 47.60 Bq/kg with an average of 350.00 ± 0.06 Bq/kg. 232Th ranged from 11.30 to 44 Bq/kg, with an average of 32.00 ± 0.40 Bq/kg. 40K ranged from 115.10 to 454.80 Bq/kg with an average of 294.99 ± 1.31 Bq/kg. Gamma-ray hazard levels were calculated using a variety of methods, including the Radium equivalent with an average of 104.37 Bq/kg, internal and external hazard indices with an average of 0.28 and 0.38 respectively,
Assessment Of Biochar Properties Derived From Treated And Untreated Coconut Frond As A Potential Solid Fuel
(2023-03)
Nur Syairah Binti Mohamad Aziz
This study is performed with the objectives of evaluating the properties of biochar produced from slow pyrolysis of coconut frond and to study the influence of feedstock pre-treatment on the properties of CF biochar. This research also aims to assess the potential of CF biochar and CF feedstock as a solid fuel by evaluating the properties of CF bio-briquette.
Assessment Of Coconut Flesh Waste And Its Solid Biochar For Briquette Production
(2022-09)
Nurhidayah Binti Mohamed Noor
The main objective of this study is to investigate the potential of coconut flesh waste (CFW) biochar from pyrolysis for solid biofuel (briquette) production. The CFW biochar was produced via mild pyrolysis from 200°C to 300°C and slow pyrolysis from 350°C to 600°C.
Assessment Of Geothermal Prospective Area Using Integrated Multi-Spatial Data Analysis At Northeastern Nigeria
(2022-04)
Abubakar, Yusuf
Spatial mapping of prospective geothermal zones is an important apparatus used in an initial exploration of renewable form of energy in the World. Previous studies have ignored the role of radiogenic heat sources in the construction of the models of their geothermal potential maps. Hence, left an incomplete study gap, where a vital aspect of earth’s heat is ignored. Therefore, the present study employed the radiogenic heat together with other parameters in mapping and analysis of areas of variable geothermal potentials using the GIS-based multicriteria evaluation approach. This study is the first geothermal study that accounted for the radiogenic heat in conjunction with other parameters for analysis of potential of this relatively not known geological location.
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).
Attribute Analysis Of Electromagnetic Waves In Different Mediums Using Ground Penetrating Radar
(2022-09)
Roslan, Iffah Zalikha
Ground-penetrating radar (GPR) has been widely used to detect shallow subsurface geological features and man-made buried objects such as utilities and archaeological structures. It is critical to interpret GPR data thoroughly to provide reliable interpretations of near-surface structures, as certain types of buried objects frequently generate similar GPR reflection signals. Thus, this research aims to identify the factors affecting electromagnetic wave (EM) propagation in the subsurface using GPR and to analyze the EM wave attribute in several media and survey geometry as well as to produce a basic guideline for GPR practitioners in interpreting the GPR data. The data acquisition in this study is divided into two parts; 1) experimental model and 2) field study. In the experimental model, radar-wave signals were investigated with varying object geometry. Results indicated that when the upper layer/medium had a lower relative permittivity than the layer/medium underneath, the polarity is normal. By contrast, the reflection polarity is reversed when it is reflected from a material with a lower relative permittivity than the material above it. The greater the relative permittivity contrast, the greater the reflection coefficient, and hence the easier it is to delineate layers and discover subsurface features. The reflection coefficient of reflectivity contrast quality is divided into weak (<0.3), good (0.3-0.5) and excellent (>0.5).
Black Silicon Fabricated By Aluminium-Assisted Chemical Etching For Solar Cells
(2023-03)
Shahnawaz Uddin
In this research, aluminium (Al) catalyst is used to fabricate nanoporous black silicon (b-Si) via a newly developed process, called aluminium-assisted chemical etching (AACE). Al as catalyst having a low diffusivity (0.94 cm2/s) slows down the etching rate in the AACE process for a better control over the morphology of nanopores and makes the AACE process low-cost too.
Black Silicon Fabricated By Silver-Assisted Chemical Etching For Flexible Solar Cells
(2023-03)
Omar, Halo Dalshad
Monocrystalline silicon (mono c-Si) dominates more than 90% of photovoltaic market due to increasing solar cell efficiencies, technology maturity and reducing technology cost. Currently, photovoltaic manufacturing uses solar cells with 180 μm thickness. To reduce the technology cost, one promising strategy is by reducing the c-Si wafer thickness below 100 μm, whereby the wafer becomes flexible. Furthermore, flexible c-Si introduces new features including flexibility, light weight and makes thin c-Si highly attractive for flexible solar cells. Most importantly, thin c-Si solar cells usually demonstrate higher open circuit voltage (Voc) due to the lower bulk recombination and more efficient electron-hole pair extraction. However, one big challenge of the thin c-Si is the insufficient light absorption due to the indirect bandgap of the c-Si. Additionally, planar c-Si exhibits a high broadband reflection of around 35% within 300-1100 nm wavelength region, which further reduces the light absorption in the c-Si. To improve the light absorption in the thin c-Si wafers, black silicon (b-Si) offers a great potential for solar cell application since it yields a superior broadband light absorption within 300-1100 nm wavelength region. This is attributed to refractive index (n) grading effect,
Brain Mri Images Quality Enhancement Using Image Processing Techniques
(2023-07)
Vispalingam, Asvhini Seema
Image quality of MRI images is important for diagnostic purposes. In this research, MATLAB software version R2016a is used for image pre-processing and processing operations which includes image enhancement, noise reduction, and morphology image processing and thresholding ad edge segmentation techniques. The images were analysed quantitatively and qualitatively in this experiment. ImageJ software was used to analyse the images quantitatively. This experiment was done using two brain tumour MRI images. The images are acquired from an online platform; The Cancer Images Archive with public access. The two patient’s identities were kept discreet in the TCIA domain. Image 1 is of a female patient of 63 years old and image 2 is of a male patient of age 58 years old. The first step in image pre-processing is filtration with median and mean filters. Filtration aims to reduce the noise present in images. Two filter masks were used for mean filtering. They are 3×3 mean filter mask and 4×4 mean filter mask. Three image contrast enhancement techniques were studied in this experiment. They are the manual and MATLAB contrast stretching method, histogram equalization method and Contrast Limited Adaptive Histogram Equalization (CLAHE) method. The thresholding technique was applied to the images for the qualitative analysis of the images. The thresholding was conducted according to Otsu’s thresholding method. In this experiment, several threshold values were experimented with to obtain the best image thresholding.
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.
Characterization Of Soil Shear Strength Model From Electrical Resistivity And Seismic Refraction Methods
(2022-07)
Balarabe, Bala
For a robust and detailed subsurface characterization, the present study characterizes soil cohesion and friction angle models from post inversions of electrical resistivity and seismic refraction tomographic datasets, and geotechnical data using shear strength test and multiple linear regression (MLR) methods. It further correlates the subsurface at various sites from geotechnical and geophysical perspectives using the developed models and validates the reliability and efficacy of the models at different locations. Three models were therefore built; firstly, simple linear models were achieved between shear strength and moisture parameters with only resistivity parameter. Secondly, resistivity and seismic refraction velocity parameters with the shear strength and moisture parameters were determined as the MLR models. Two of the MLR models, soil cohesion and friction angle, were accepted based on the strong relationships among the parameters, such as coefficient of determination (R2), 0.777 and p-values, <0.050, while the other rejected. The obtained coefficients of the accepted models were transferred and applied for the estimations of 2D soil cohesion and internal angle of friction models for validation at Minden_USM, Batu Uban, Cahaya Gemilang and Bukit Gambir areas. The developed models demonstrated good performance, based on the accuracy assessments; < 5%, and < 10% for the root mean square error (RMSE) and mean absolute percentage error (MAPE) respectively. The approach generated, new geotechnical models, rebuilding of subsurface geometries in two-space.
Defective Particle Surface On Zno And Its Influence On The Optical, Electronic And Toxicity Properties
(2023-07)
Kamaruddin, Nur Mariam
Chemotherapy, radiation, and surgery are the most common treatments for cancer in recent years. Cancer is a disorder marked by uncontrolled malignant cell proliferation. Although in theory, all these treatments should be very successful at destroying cancer cells, nonselective therapeutic techniques nevertheless carry several major risks. Recent research has shown that zinc oxide (ZnO) has the potential to overcome these side effects due to its high biocompatibility, ease of surface functionalization, ability to target malignancy, and drug transport capability. These benefits allow ZnO to be chosen as biocompatible and biodegradable platforms, as well as being investigated for cancer treatment. The main objective of this study is to investigate how surface modification via various annealing ambient affects the properties of ZnO structures and how they relate to breast cancer cell survival (MCF-7). The morphological, structural, electrical, and optical properties of three ZnO (i) as grown (ZnO-AG), (ii) oxygen annealed (ZnO-O2) and (iii) nitrogen annealed (ZnO-N2) samples were investigated. The general morphologies of ZnO samples comprise rods, plates, tripod, and drumlike structures, as well as irregular shapes. The ZnO had a diameter of 30-200 nm while thickness 90-400 nm. Electron spectroscopy imaging (ESI) revealed oxygen and zinc atoms (O: Zn) distribution on the ZnO samples. On the ZnO surface, ZnO-O2 had a greater O:Zn ratio while ZnO-N2 had a lower O:Zn ratio. At 700oC, there was more oxygen adsorption on the ZnO-O2 surface whereas there was more oxygen desorption on the ZnO-N2 surface. Surface conductivity is reduced by ZnO-O2, whereas surface conductivity is increased by ZnO-N2. The highly polycrystalline properties of the ZnO sample were revealed by the XRD measurement.
Deformation Monitoring Of Marwat-Khisor Ranges, Pakistan Using Interferometric Synthetic Aperture Radar
(2023-02)
Fadzil, Fakhrul Hazwan Ahmad
Main Frontal Thrust (MFT) represents the southern boundary of Himalaya, which accommodated the current orogeny of Eurasian-Indian tectonic plate’s convergence. The deformation pattern and structural style of MFT are crucial for understanding the tectonic activities. A chain of fold-and-thrust (FAT) belts (Salt-Trans Indus Ranges) are identified as the MFT in the western Himalaya. The Salt Range had propagated southward at an average rate of 5-10 mm/year in the influence of salt tectonics. Although the Trans Indus Ranges had indicated an active Quaternary tectonics, the fault slip rate and direction was unknown. This study focused on the Marwat-Khisor Ranges (a segment of Trans Indus Ranges), the youngest part of the MFT in the western Himalaya. Remote sensing techniques such as Interferometric Synthetic Aperture Radar (InSAR) Permanent Scatterer (PS), lineament extraction and geometric analysis of salient were implemented to investigate the deformation mechanisms and active tectonics. InSAR processing of 80 Sentinel-1 images showed the Marwat-Khisor Ranges were uplifting in the satellite line-of-sight at an average rate of 3-7 mm/year dated from 18th October 2014 to 18th June 2019. The Marwat-Khisor Ranges are the hanging wall sequence that ramped up section above the partially emergent Khisor Thrust where surface uplift is expected.
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.
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.
Development Of Breast Phantoms For Ultra-wideband (Uwb) Microwave Imaging Systems
(2023-08)
Ayob, Nur Syuhada
Ultra-wideband (UWB) microwave imaging is a promising new alternative technology for detecting breast cancer tumours in the early stages. However, the calibration kit is required in this study to obtain accurate results. Therefore, breast phantoms with properties similar to biological breast tissues (skin, fat, gland, and tumor) were created. 15 % polyvinyl alcohol (PVA), wheat flour, and deionized water were used for the fabrication of phantoms. Different wheat flour concentrations, wfc (%) (0 % to 50 %) were added to the PVA-C solution to fabricate different types of breast tissues. Lactic acid was used for preservation purposes. The dielectric properties of the fabricated phantoms were tested utilising a setup system consisting of a vector network analyzer and a dielectric coaxial probe. The reflection coefficients were measured using a fabricated insulated monopole sensor. The frequency range for all measurements was between 0.5 and 50 GHz. The dielectric properties of the fabricated phantom were found to be similar to those of real gland and tumor tissues. The wfc (%) of 79.33 %, 124.4 %, 44.13 % and 25.56 % acquired using the prediction model I have shown can be used to simulate skin, fat, gland, and tumor tissues, respectively. The results also showed agreement with the Cole-Cole model for skin, fat, gland, and tumor phantoms. This research also found that the wfc (%) in PVA-C-based breast phantoms can be determined using an insulated monopole sensor.
Development Of Novel Geophysical–geotechnical Relationships Of Granitic Environments In Penang Island, Malaysia
(2023-08)
Sunny, Akingboye Adedibu
The characterization of near-surface soil-rock conditions is challenging in tropical crystalline terrains due to complex geology and lack of distinct stratigraphic markers. These features can adequately be mapped using velocity-resistivity relationships via statistically optimized soil-rock quality modeling, especially in areas with overburden <50 m. The approach has not been used in tropical granitic terrains. To achieve the research goals, Penang Island, Malaysia; a tropical granitic terrain, was considered a suitable area due to its intrinsic soil-rock characteristics and the need to resolve environmental-related issues. This research, therefore, develops velocity-resistivity statistical relationships for granitic terrains based on complex collocated geotomographic (electrical resistivity tomography and seismic refraction tomography [SRT]) modeling. To this end, four detailed methodological scenarios were utilized, leveraging borehole logs, rock quality designation (RQD), soil penetration test (SPT N-values), and supervised regression analysis. The results show that the borehole lithologic logs correlate well with resistivity- and SRT-based lithological models at the eastern (Sungai Ara), southern (Batu Maung), and northern (Jelutong) sections of Penang Island. The areas are characterized by sandy silt topsoil, silty sand to sandy weathered units, weathered/fractured units, and integral/fresh granitic bedrock. The rock quality assessment, via borehole-based RQD, and SRT- and resistivity-based RQD models, had empirical prediction accuracies of 95.8% to 100%.
Dose Verification Of Brass Mesh Bolus For Contralateral Breast Post-mastectomy In Three-dimensional Conformal Radiotherapy Technique
(2023-09)
Buang, Sakinah
Post mastectomy radiation therapy (PMRT) prescribed to patient that undergo breast mastectomy. With the bolus application in PMRT, it has shown few limitations whereby current water equivalent bolus (WEB) unable to conform irregular surface consistently. Besides that, dose inhomogeneity arises in contralateral breast (CB) and organ at risk (OAR) during PMRT. It is established that brass mesh bolus (BMB) has potential in conforming irregular surface with the aim to treat chest wall site in delivering maximum dose and sparing OAR. This study aims to determine the feasibility of BMB as an alternative to bolus and to verify dose received by CB and target breast with application of BMB in 3-dimensional conformal radiation therapy (3DCRT). This study are designed based on three main parts ; firstly is to characterize dosimeters (Ludlum detector, ionization chamber and nanoDotTM) based on Cobalt-6o and 6-MV photon energy; secondly is to measure the radiological, physical and dosimetric properties of BMB by measuring the density using three methodologies (Image-J analysis, conventional density and CT analysis), mass attenuation coefficient, mass energy absorption coefficient and percentage depth dose (PDD) ; and lastly is to verify the radiotherapy treatment with the BMB to the PMRT heterogenous phantom by 3DCRT. Statistical analysis evaluation in accordance with the international standard was applied. The results revealed that all dosimeters have high linearity with acceptable traceability

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