PHYSICAL SCIENCE PROJECT TOPICS AND MATERIALS

As the global economy constantly continues to rise, the global demand for power and energy sources are synonymously increasing. This raises the consumption of fossil fuels which produces two major related issues; depletion of fossil fuel reserves and environmental greenhouse emission problems which not only pose pollution problems but also climate change issues. These issues have been projected as one of the global urgent and important challenges to be tackled. There is, therefore, a need to develop alternative energy sources that are clean, sustainable, and meet up with the rising global demand. In view of this, a lot of renewable energy sources have been explored but they generally have a commonly associated issue; they are seasonal. Most renewable clean energy sources are highly dependent on the time of day and regional weather conditions. The need for the development of related energy conversion and energy storage devices, therefore, arises in order to take the harnessing of these renewable clean energy sources to their best efficiency. Energy conversion and storage devices showing the greatest potentials currently include; batteries, supercapacitors and fuel cells [1].

As inorganic components dissolve in water, one of the parameters that changes significantly is conductivity. Conductivity is a measure of the ability of water or an aqueous solution to carry an electric current. The current flow in water depends on the presence and concentration of ions in the water and therefore conductivity is often used as an indirect estimate for dissolved solids content of a solution (Coury, 1999). High total dissolved solids (TDS) discharged to rivers and streams can promote eutrophication, destroy sensitive ecosystems and endangers aquatic species (e.g., the cutthroat trout and cui-cui fish) in rivers and lakes (Mortensen et al., 2008). These water bodies can also be rendered unwholesome for both animals and plant usage, especially for people living in catchment areas, who do not only use these waters for drinking but also for other domestic purposes.

The extraction of specific value minerals from their naturally occurring ores is variously termed “ore dressing,” “mineral dressing,” and “mineral beneficiation.” For most metalliferous ores produced by mining operations, this extraction process is an important intermediate step in the transformation of natural ore to pure metal. Although a few mined ores contain sufficient metal concentrations to require no beneficiation (e.g. some iron ores), most contain relatively small amount of the valuable metal, from perhaps a few percent in the case of base metals which are commonly intergrown with economically important and unimportant (gangue) minerals on a microscopic scale in the iron ore gangue.

Chemical and physical methods for the synthesis of magnetic nanoparticles for cancer detection and treatment often involve toxic chemicals, high cost and the formation of non-stable nanoparticles. This prompted the development of fundamental understanding of the synthesis of magnetic nanoparticles, which are biocompatible, cost effective, stable, localized and environmentally friendly in the presence of magnetotactic bacteria. In this work, fundamental understanding of the underlying mechanisms involved in the formation of magnetic nanoparticles by magnetotactic bacteria are unraveled. Soil dwelling microbes that respond to magnetic pull were cultured in the presence of ferrous salts in a magnetic spirillum growth medium (MSGM). A comparative analysis was made whereby a positive control Magnetospirillum magneticum and an indigenous isolated strain were used in the biosynthesis of magnetic nanoparticles. The dependence of particle shape and size on pH and time, were elucidated using a combination of transmission electron microscopy (TEM) and UV-visible spectrophotometry. The implications of the results are discussed for the development of magnetic nanoparticles for the detection and treatment of cancer.

The increasing rate of cancer patients worldwide, and especially Africa has led to numerous efforts to battle it. One approach to this has been localized drug delivery to reduce the quantity of drugs needed for therapeutic effect. Poly-di-methyl-siloxane (PDMS) is an elastomer with much focus on it as a microfluidic device. PDMS is one polymer of choice for localized drug delivery due to its biocompatibility, transparency, and ease of fabrication. However, its highly hydrophobic nature does not allow it to be used without modification. This work presents results of experimental and computational methods for PDMS surface modification. Also computational results of shear assay model for the effects on surface modification on cell adhesion is present. Modifying the surface of the PDMS was done by varying the mix ratio and curing temperatures after fabrication. The results from the experiment shows that low base to curing agent ratio and increasing curing temperature gives a highly stiff PDMS. Also, the PDMS treatment via boiling water and Ultraviolet Ozone (UVO) methods makes it hydrophilic with the generation of hydroxyl (OH) group on the substrates. These studies provided understanding of cell-surface interaction on a multi-scale. Morphological studies with Scanning Electron Microscope (SEM) reveal a layer and textured featured formed on UVO treated and PLGA coated PDMS. Shear assay model showed that cells on modified PDMS surface low energy release rate on application of shear load. This signifies that cells adhered to the modified surfaces better, thus could not be easily detached.

Consumption of contaminated water may result in several water-borne diseases, including hepatitis, typhoid, cholera, dysentery and other diseases that cause diarrhoea. One of the ways this problem can be prevented is by the use of household water treatment and safe storage. As a result of this, the ceramic water filter, which is one of the effective water treatment techniques, was studied and evaluated to provide information that, will help improve their performance and promote their use.

This research presents the design, construction, and analysis of the performance of a mixed-mode solar dryer for crops. A mixed-mode solar dryer utilizes direct solar radiation from the sun as well as input heat ducted from the solar collector inlet which is directly connected to the dryer. Such dryers have been shown to outperform passive solar dryers as it was also shown in this work using drying kinetics. Tomatoes were dried in the drying chamber under the mixed-mode condition. The maximum dryer temperature obtained was 39.2, while the lowest relative humidity in the dryer was 32%. These conditions are shown to be only fair for drying of tomatoes as it prolongs drying time. The system’s performance was largely affected by poor insolation and high heat losses during chosen drying days. Based on drying kinetics, a drying rate of 2.88units/day was obtained during the chosen drying days. With this rate, the dryer can dry 2kg of tomatoes within three days.

Polypropylene is widely used today in industries and also at home and its production has increase drastically over the years making polypropylene products a major contributor in environmental waste. Therefore, instead of throwing away wasted or unusable polypropylene to where it may cause harm to the environment and the whole biodiversity, recycling comes to rescue. The objective of this study is to determine the change in properties of polypropylene with recycling.For this purpose, the mechanical properties of polypropylene using five recycling generation were determined.

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 enzyme. The pH used was 4.0, 6.0, 6.5, 7.0 and 7.4. From the study, it was observed that lipase enzyme increased the rate of polymer degradation and thus the rate of drug release from PLGA. This experiment also shows that PLGA degrades faster in acidic medium. This also caused the kinetics of drug release to be higher in acidic medium than in alkaline or neutral medium.

Failure of offshore oil and gas pipelines occurs under certain conditions due to some applied mechanical forces. These conditions constitute a potential threat to the integrity of in-service life span of the pipelines which can lead to loss of resources and environmental pollution. Several studies have shown that pipelines fail as a result of Welding, Fatigue Crack Growth, Corrosion Fatigue, Stress Corrosion Cracking, and Erosion due to fluid flow. This paper presents a model by using fracture mechanics to analyze the allowable applied stresses an in service pipeline needs to withstand in minimizing crack growth. Furthermore, the crack size, crack shape and hole radius with pipe thickness will be modeled. The modeling results will be validated using experimental data. The implications of the results will be discussed for the design or development of a robust oil and gas pipelines.