ABSTRACT The effect of cooling rate and modification on the microstructure and tensile properties of Al-Si-Mg alloys was carried out. Castings were produced using a stepped pattern that has different section thicknesses. Sand casting technique was used. A thermocouple inserted into the mould cavity recorded the cooling rates for the different sections. The Al5.43%Si3.83%Mg which was melted in the crucible furnace was modified with sodium (Na) and strontium (Sr) in separate cases. T...
BACKGROUND The numerous limitations of inorganic solar cells has led to keen interest and exploitation of organic solar cells in recent times. They offer several advantages such as lightness, mechanical flexibility, low production cost, ease of processing and have a high potential for large area solar conversion1 . The properties, performance and lifespan of these solar cells depend on the properties of the active layer and interface between the components1 . Thus far research efforts have b...
ABSTRACT Drilling fluids play sophisticated roles in the drilling process which include, keeping formation fluids at bay, stabilizing the wellbore without damaging the formation, lubricating the bit and drill-string and clearing cuttings from the bit face. Weighting agents are compounds that are dissolved or suspended in drilling fluid to increase its density. The effect of density also contributes to the stability of the borehole by increasing the pressure exerted by the wellbore fluid onto...
ABSTRACT The theoretical study of methylammonium bismuth halide, (CH3NH3)3Bi2I9, was simulated using SCAPS 1D software package. The effect of the bismuth perovskite absorber layer thickness on the solar cell performance was investigated using three different materials (organic and inorganic) materials such as Cu2O, CuI, and spiro-OMeTAD as hole transporting layer (HTL), and four different materials (organic and inorganic) materials such as ZnO, TiO2, PCBM, and P3HT as electron transporting l...
ABSTRACT This thesis is focused on fabrication of biodegradable implantable devices for extended localized drug release. Paclitaxel (PT) was used as cancer drug in the study. Poly lactic –co- glycolic acid (PLGA) is a polymer used for drug elution. In this work, the role of enzymes on the degradation of PLGA, Effect of different pH on the degradation of PLGA and the kinetics of drug release was elucidated. PLGA ratios of 75:25 and 85:15 were used. The enzyme used in the study is lipase enz...
ABSTRACT The growing global understanding of ecological footprints and environmental pollution invented by humans is gainfully affecting our material design practice, pushing the search for more sustainable alternatives, and development of natural biocomposites. In this research, the natural ability of saprophytic fungi to digest and bind lingo-cellulose is utilized to develop natural biocomposite materials for novel applications in design and architecture. This study aims to provide an insi...
ABSTRACT When a well is drilled, the equilibrium in-situ stress is changed. In order to support the stress relief induced by the drilling and to prevent hydrocarbon influx into the cavity, the borehole is filled with a fluid. These operations create new stress configurations. The main point in wellbore projects is the definition of the drilling fluid density to keep the wellbore stable. The lower bound to the fluid density is the collapse stress that is the limit to shearing. The upper bound...
ABSTRACT Like any industry, the economic success of the oil and gas industry can be no swifter than its success in corrosion control/prevention. Some oil and gas industries operate in hostile offshore environment that harbors significantly quite substantially different corrosive agents including ions of chloride, Cl- , bicarbonate (HCO3 - ), hydrogen sulfide (HS- ), sulfide (S- ), etc., coupled with gases such as oxygen (O2), carbon dioxide (CO2), just to name a few. Oil and gas structural m...
ABSTRACT Barite is an exceptional non-metallic mineral composed of barium sulphate and it is used mainly by the oil and gas industry as drilling mud in deep drilling, where high pressure is encountered. The specific gravity of barite should range from 4.2 to 4.6 in order to be used as drilling mud. In Nigeria, barite deposits are found in veins and cavities hosted by varieties of rocks. In this work, barite deposits in various troughs of Nigeria have been sampled and analysed for the purpose...
ABSTRACT Ceramic water filters are promising household water treatment technology, as they are capable of removing waterborne pathogens and thereby reducing diarrheal disease. Flow rates are the main quality control criterion for manufacturing, and multiple theoretical flow rate models have been published. This dissertation presents the results of combined experimental and theoretical studies of flow rate variation in ceramic water filters in frustumand disk-shaped ceramic water filters. Als...
ABSTRACT Wearing of mining tools leads to high replacement costs, machine downtime and loss of business opportunities. This work was however, aimed at improving the wear resistance of AISI 1065 and 1070 proeutectoid steels used for (barite) mining operations. To achieve this, the case hardening method adopted was pack-cyaniding with dried and pulverized cassava leaves (a type of carbonitiriding) at 700, 800, 850 and 900°C. After the carbonitriding process, the 1065 steel was quenched and tem...
Abstract Our ability to power modern airplanes and land based engines depends largely on the thrust generated most importantly by aero engines. Over the past 30 years material cost has become an important factor, especially in commercial aero engines where light weight and high temperature materials are needed for improved efficiency and specific thrust. The required combinations of high temperature properties has led to the applications of nickel-based superalloys and most recently gamma ba...
ABSTRACT The morphology of active layers of organic solar cells plays crucial roles in achieving good performing devices with longer life span. The process of fabricating these devices involved post deposition thermal annealing, which increases the crystallinity and enhances phase-separated domains of deposited active layer components. A blended composite of regioregular poly(3- hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) is used as the active layer in this BHJ sol...
ABSTRACT The Luteinizing Hormone-releasing Hormone (LHRH); also known as a GonadotropinReleasing Hormone can be utilized for targeted therapy with cytotoxic analogs, in which prodigiosin is linked to the [D-Lys6] LHRH. Our studies demonstrate receptor-mediated actions of the cytotoxic LHRH analog in LHRH receptor positive breast cancer cells. Chemotherapy today is the only systematic therapy for patients with triple negative breast cancer cells. About 50% to 64% of human breast cancer expres...
ABSTRACT Implantable Bio-Micro-Electro-Mechanical Systems (BioMEMS) represent a new class of devices that can provide localized cancer drug delivery by the combined effect of chemotherapy and hyperthermia which gives it an advantage over prior devices. The current work presents the results of a theoretical and experimental study of a novel implantable drug delivery device. Prototype Poly-di-methyl-siloxane (PDMS) packages with well-controlled micro-channels, and a drug storage compartments w...