Abstract: Research on semiconducting metal oxide (MO) nanostructures is a fascinating field that has received massive interest due to their significant physical and chemical properties which can be useful in the development of highly efficient nanodevices. Incorporating impurities such as metal elements into the MO matrix offers tailored properties for various applications. Doped MO nanostructures exhibit modified structural, optical, electrical and morphological properties rendering th...
Abstract: Green nanotechnology is an innovative research field with emphasis on the development of methods that minimize the use of health hazardous substances for environmental remediation. This study reports on the biosynthesis of nanostructured multilayer graphene (MLG) and zinc oxide (ZnO) from natural extracts for environmental applications. ZnO nanoparticles are fabricated for the first-time using Ageratum Houstonianum leaf extract as an effective chelating agent. Besides this, a ...
Abstract: Continuous discharge of textile wastes such as dyes into the water bodies deteriorates the quality of water. Therefore, the removal of these materials from the wastewater should be a priority due to their carcinogenic properties, which pose a health hazard to both human beings and aquatic life. The use of advanced oxidation processes (AOPs) for example heterogeneous photocatalysis has been broadly studied due to their efficacy in the removal of such organic contaminants. Engin...
Abstract: The development of transparent conducting oxide materials has gained an increased interest in the scientific community for developing efficient low cost optoelectronic devices. The effect of Cd precursor on structural and optical properties of sol-gel synthesized Zn0.9Cd0.1O nanostructured films has been studied by using XRD, AFM, optical absorption and emission spectroscopic techniques. X-ray diffraction confirms the hexagonal wurtzite crystal structure of the deposited films and ...
Abstract: Doping is an effective material re-engineering technique, which provides a possibility of improving properties of materials for different applications. Herein, a Zr-doped TiO2 thin film was deposited applying the chemical spray pyrolysis method and the influence of varying zirconium dopant concentrations on the properties of the film was studied. Morphological studies showed that the Zr–TiO2 films were homogeneous with smaller grain sizes compared to the undoped TiO2 films. As-de...
Abstract: Agricultural residue-based fibrous (ARF) materials have been identified to be a commercially viable solution for energy-efficient building insulation application. ARFs have various advantages over synthetic fibers including environmentally friendly, light weight, low cost, and competent mechanical properties. Meanwhile, in many African countries including Botswana, the expertise to manufacture building insulators by using ARFs is scarce and consequently building insulation material...
Non-renewable energy sources produced from natural coal and oil may result in climate change and global warming as greenhouse gases are to the environment. This is why the main utilization of energy sources on renewable and alternate green energy to deliver power. Thus, a microbial fuel cell device is one of the cost-effective and environmentally friendly energy conversion devices that uses renewable organic wastes as fuel source and converts this stored chemical energy in to useful b...
ABSTRACT A semi-mechanistic model for predicting the flow behaviour of Fe-Mn-Mo steels displaying transformation-induced plasticity is developed in this paper. The model, based on the law of mixtures, takes into account the work-hardening of the individual principal phases (namely, lath-martensite and austenite/epsilon martensite). The composite strength of such a steel may be given by a modified law of mixtures which incorporates a dislocation density effect. To test the validity of the m...
ABSTRACT Thermodynamic data is made use of in calculating fraction of metal solidified in solidification simulation. However, thermodynamic data for many industrial alloys in their solidification ranges are not available for most practicing engineers. It is thus desirable to develop reliable equations that can be used in calculating fraction of metal solidified for solidification simulation. This work has developed an equation to calculate fraction of metal solidified for AlSi7Mg alloy solid...
Abstract This work has investigated the corrosion behavior of low carbon steel subjected to four different modes of iso-thermal heat treatment and then immersed in a neutral buffer corrosive medium containing carbonate and chloride ions.The low carbon steel material was cut into twenty small pieces of length 18±2mm, put in groups of five and subjected to: Annealing, Hardening, Normalizing and tempering, each corresponding to an iso-thermal mode of treatment. The samples were ground and poli...
Abstract This study investigated the effect of magnesium and calcium as spheroidizers on the graphite microstructure in cast iron. The cast iron samples were melted in an induction furnace with charge of known composition and, magnesium and calcium of known percentages were added as spheriodizers to the molten metal in the mould during the casting process. From the microstructure of the as- cast specimens it was observed that the use of 100% Mg and a combined addition of 60% and 40%Ca as sph...
ABSTRACT The properties of cast iron grade GL 250 are dependent on the microstructures developed during casting. These microstructures are in turn dependent on the composition of the alloy, type of mould and other numerous casting practice variables such as shake-out time, pouring temperature, mould ambient conditions and inoculating technique. In this work, the effect of silicon content and shake-out time on the grain size (GS) and hardness properties of GL 250 cast iron was studied using a...
ABSTRACT This term paper contributions nanotechnology and dives into the world of nanotechnology and its and possibilities it can offer to the society The and nanomaterials immense impact of extends from its medical, ethical, mental, legal environmental applications, to fields such as engineering, biology, chemistry, computing, materials science, and communications. Alas, nothing is ever as it seems and perf...
The quality of castings in a green sand mould is influenced significantly by its properties, such as green compression strength, permeability, mould hardness, and others, which depend on input parameters. The relationships of these properties with the input parameters, like sand grain size and shape, binder, water, clay, etc. are complex in nature. The goal of this paper is to determine the green sand mould compressive strength in case of input parameters. A good moulding sand however, must p...