ABSTRACT Dual Digestion is a two stage system that combines autotherm·a1 thermophilic aerobic pre-treatment with conventional anaerobic digestion. The practicability of the system using pure oxygen is well proven. Disadvantages are the high cost of the pure oxygen and the absence of a detailed evaluation of anaerobic digester performance. This report discusses the results of a full-scale investigation into the dual digestion system (184m3 aerobic reactor and 1800m3 anaerobic digester), carri...
BACKGROUND Integral to the biological nutrient removal (BNR) activated sludge system is the biologically mediated process of denitrification. Not only does this process reduce the N load to the environment, but it also has the advantages of alkalinity recovery and reducing the oxygen demand. Further, the denitrification protects the biological excess P removal (BEPR), if included, from the deleterious effect of recycling nitrate to the anaerobic reactor (Wentzel et al., 1990). Accordingly, qu...
ABSTRACT Terrorism, with explosions both in and outside buildings, has become a significant problem in the world. There are already several houses of unreinforced masonry, some of which are historical. But under blast loading they do not function well. Retrofitting methods have been developed to protect masonry buildings. Some research work has been carried out in recent years to study the impact of retrofitted URM walls; these experiments require usually significant time and funds. Also, wit...
ABSTRACT This thesis explores the development of a fixed wing unmanned aerial vehicle for delivery given the deplorable condition of roads leading to certain rural medical centers. This unmanned aerial vehicle has to be of the fixed wing type due to the weight to be carried and the distance which is to be covered. The thesis seeks to provide a greener alternative using a recyclable material i.e. strawboard for the body of the UAV, the UAV is also of a modular design hence it can easily be con...
Abstract Machining of Inconel 718 with whisker reinforced ceramic tool gave better performance in terms of tool life under high-pressure coolant supplies up to 15MPa compared to conventional coolant supplies. The use of 15MPa coolant supply pressure tend to suppress notching during machining thus improving tool life, while the use of higher coolant supply pressure of 20.3MPa did not show improvement in tool life due probably to accelerated notch wear caused by water jet impingement erosion. C...
Abstract The assignment problem is a special type of linear programming problem which is concerned with allocating to operators (men) to n machines (tasks) given that each operator is qualified for certain of the tasks. The output from each task is given as a function of the number of qualified men assigned to it. The assignment model is to.be solved by conventional linear programming approach or transportation model approach. It is a square matrix, having equal number of rows and columns. ...
ABSTRACT Communication is the basis of all human interactions in the world. Thus, human beings have been struggling for years to introduce different communication transmission technologies. Lately, the two technologies namely Broadband over Power Line (BPL) and 4 th Generation/Long Term Evolution (4G/LTE) have been trending topics. Many researchers have been researching these technologies from different angles to make them better for use. There is a co-existence between BPL and LTE technolog...
ABSTRACT This paper presents a new methodology for weld-metal properties optimization from welding flux ingredients. The methodology integrates statistical design of mixture experiment with mathematical programming optimization technique. The mixture experiment is responsible for the modeling of the weld-metal properties as a function of welding flux levels while mathematical programming optimizes the model. Data and confirmed models from the literature were used to perform optimization on th...
ABSTRACT . The ice-maker freezer) was designed, constructed and tested. The ice-making machine is to freeze 27kg of water in 9 diflerent comparlments in 12 hrs. The quantity of heat lo be rmoved in order to achieve peezing is 12556.89 and this is used to determine the refiigeration tonnage of the machine (0.124 ton).' Polyurethane and Galvanized steel sheets have been selected for insulation and cabinet materials respectively due to their low thermal conductivities and high 'corrosion resista...
ABSTRACT Intelligent Tool Condition Monitoring (TCM) is an essential requirement in the drive towards automated machining operations. In this paper, a Multi-Layered Perceptron (MLP) neural net-work model has been developed for on-line condition monitoring of tool wear in high-speed turning of Titanium-based alloy (Ti-6Al-4V). Machining trials were conducted for typical rough and finish turning operations with cutting speed (90 – 120 m/min), feed rate (0.15 – 0.2 mm/rev), and depth of cut ...
Abstract This paper presents experimental and simulation study of the effects of stress on microstructure and failure morphology of low carbon steel under plane stress conditions. The study has revealed large extension of grains at the point of fracture and, stress and strain looped around the pearlitic faces of the microstructure matrix. The stress and strain distributions in the microstructure have shown that concentration of stress and strain on the pearlite were instrumental to oblique fr...
Abstract A gas-fired oven for commercial production of bread was designed and constructed using locally available material, and was subjected to various'tests to come out with its performance characteristics. Itsperformance was evaluated and then compared withsrespect to the total time required to bake a specified mass of white flour dough using the gas oven with that used by clay wood fired oven for the same mass of white flour dough. ., The outcome of the test result indicated that the ni&x...
ABSTRACT A survey was carried out to identify the types of crops popularly stored, the structures commonly used and problems experienced with produce storage in the Kingdom of Swaziland. Respondents included operators of government storage facilities, non-governmental organizations providing food relief, millers, large-scale farms, homesteads and artisans who fabricate metal tanks. Maize, the national staple food, was stored by all homesteads essentially for family consumption. It was the com...
Abstract This paper investigates the dynamical behaviour of a duffing oscillator using bifurcation diagrams. There has been growing interest and challenges in engineering dynamics to characterize dynamical systems that are chaotic using bifurcation diagrams. The relevant second order differential equations using Runge-Kutta method were solved for ranges of appropriate parameters. The solutions obtained were used to produce the bifurcation diagrams using Microsoft excel 2007. Since an average ...