David O. Obada

Effect of mechanical activation on mullite formation in an alumina-silica ceramics system at lower temperature

Purpose This work aims to analyze the effect of mechanical activation on structural disordering (amorphization) in an alumina-silica ceramics system and formation of mullite most notably at a lower temperature using X-ray diffraction (XRD). Also, an objective of this work is to focus on a low-temperature fabrication route for the production of mullite powders. Design/methodology/approach A batch composition of kaolin, alumina and silica was manually pre-milled and then mechanically activated in a ball mill for 30 and 60 min. The activated samples were sintered at 1,150°C for a soaking period of 2 h. Mullite formation was characterized by XRD and scanning electron microscopy (SEM). Findings It was determined that the mechanical activation increased the quantity of the mullite phase. SEM results revealed that short milling times only helped in mixing of the precursor powders and caused partial agglomeration, while longer milling times, however, resulted in greater agglomeration. Originality/value It is noted that, a manual pre-milling of approximately 20 min and a ball milling approach of 60 min milling time can be suggested as the optimum milling time for the temperature decrease succeeded for the production of mullite from the specific stoichiometric batch formed.

Experimental investigation into the adherence of novel coating of auto-catalyst on cordierite supports

Purpose A structural and textural characterization study has been performed to investigate the adherence of zeolite-based catalyst washcoated onto honey-comb-type cordierite monoliths. The supports were characterized by the scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) techniques. Design/methodology/approach SEM/EDS provided quantitative estimate of the washcoated monolith as the elemental composition of catalyst coating. The XRD pattern deduced that the zeolite-based catalysts were successfully mounted on the cordierite support, showing the characteristic peaks of zeolites (Zeolite Socony Mobil–5; ZSM-5) at Braggs angles of 7.88°, 8.76°, 23.04°, 23.88° and 24.36°, whereas the characteristic peak of cordierite is seen at a Braggs angle of 10.44°. Findings The BET results proved that a monolayer of zeolite may serve the need for surface area and porosity. This was evident in the increase of surface area of washcoated support as against the bare support. The obtained isotherms were of Type IV, illustrating the presence of mesopores. The adsorption and desorption isotherm branches coincided over the interval 0 < P/P0 < 0.50 and 0 < P/P0 < 0.45, showing N2 reversible adsorption for the two samples, respectively. Originality/value It was concluded that the composite materials which are ZSM-5 (Si/Al = 25) and precursors of the transition salts of copper, zinc and ceria powders were deposited on the catalyst supports, establishing the success of the coating procedure relative to the adherence of the catalyst compositions on the ceramic support.

Effects of electrode type on the mechanical properties of weldments of some steel samples produced in Nigeria

The effects of electrode types on the mechanical properties of weldments produced from three steel samples made locally in Nigeria have been investigated. Oerlikon, Santan, Power Master and Magnum electrode samples were separately used to join Homus, Universal and Spanish steel samples. The chemical compositions of the steel samples, electrodes core and coating were obtained using spectrometer before using them for the research. Mechanical properties of the weldment produced were determined and compared to the unwelded samples. This was done in order to provide information on which combination of steel and electrode type will produce weldment with optimum mechanical properties. Oerlikon electrode produces weldments with optimum tensile strength of 508.25 N/mm2 and impact energy of 152.76J for Homus Steel, it also produced highest tensile strength of 449.92 N/mm2 and impact energy of 103.042J for Spanish Steels while Power Master Electrode produced weldment with highest tensile strength of 482.96N/mm2 and ...

The impact of gasoline and synthesized ethanol blends on the emissions of a spark ignition engine

Considering pollution problems and the energy crisis today, investigations have been concentrated on lowering the concentration of toxic components in combustion products and decreasing fossil fuel consumption by using renewable alternative fuels. In this work, the effect of ethanol addition to gasoline on the exhaust emissions of a spark ignition engine at various speeds was established. Ethanol was extracted from groundnut seeds using fermentation method. Gasoline was blended with 20 - 80% of the extracted ethanol in an interval of 20%. Results of the engine test indicated that using ethanol-gasoline blended fuels decreased carbon monoxide (CO) and hydrocarbon (HC) emissions as a result of the lean- burn effects caused by the ethanol, and the carbon dioxide (CO2) emission increased because of a near complete combustion. Finally, the results showed that blending ethanol in a proportion of 40% with gasoline can be used as a supplementary fuel in modern spark ignition engines as it is expected that the eng...

Catalytic abatement of CO species from incomplete combustion of solid fuels used in domestic cooking

This study reveals a first time approach to catalytic based interventions primarily on indoor air pollution emanating from commercial and household solid fuel burning in a region in Nigeria. An intensive survey of the temperatures at different locations in the common stoves used for cooking was conducted so as to ascertain temperatures suitable for catalyst efficiency and stability. Furthermore, cobalt and iron based catalysts were prepared using ultra stable Y type zeolite as supports. The synthesized catalysts were characterized for its physico-chemical properties. The catalytic efficiency of the supported catalysts was tested using simulated exhaust gases in a fix bed reactor. The study further explored real time testing of the catalyzed ceramic monolith using two different wood species. First, the best catalyst in terms of simulated exhaust testing was selected. Consequently, a small layer of zeolite Y was deposited at 3% of the monolith weight to enhance the subsequent adhesion of the best catalyst powder to the structured monolith. Then to catalyze the zeolite Y wash-coated monolith with the cobalt precursor, the dip coating technique was used. From the results, the average values of temperatures observed from the surveyed cook stoves using wood and plant residue as fuel were confirmed to be in the range of 203–425 °C which is considered suitable for catalysts activity. The Co/ZY catalyst showed approximately 100% CO conversion (T100) at 250 °C for initial CO concentration of 1000 ppm, making it the most effective, while T100 was increased to 275 °C and 325 °C for Fe/ZY and Co-Fe/ZY catalyst respectively at an exhaust residence time of 20000 h−1. The catalytic converter in real time testing for CO abatement performed well for both wood species. Only minor differences have been noticed.

Dataset on the comparison of synthesized and commercial zeolites for potential solar adsorption refrigerating system

The purpose of this dataset is to provide a comparison between synthesized and commercial 4A and 13X type zeolites. Metakaolin produced from the calcination of beneficiated kaolin at 750 °C for 4 h was dealuminated using sulphuric acid to get the required silica to alumina ratio for the zeolite synthesis. Zeolite 4A and 13X samples were characterized along-side with the commercial variants using X-ray fluorescence (XRF), X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) and scanning electron microscopy (SEM) techniques. These analyses revealed that, the zeolites synthesized are of comparatively acceptable quality. The pore size of 120.859 nm, pore volume of 0.0065 cm3/g and surface area of 22 m2/g were obtained from BET analyses for zeolite 4A synthesized from kaolin, while the commercial zeolite 4A used as control gave pore size of 58.143 nm, pore volume of 0.2462 cm3/g and surface area of 559.13 m2/g. In the same vein, the pore size of 10.5059 nm, pore volume of 0.135847 cm3/g and surface area of 324.584 m2/g were obtained from BET analyses for zeolite 13X synthesized from kaolin, while the commercial zeolite 13X gave pore size of 7.2752 nm, pore volume of 0.135951 cm3/g and surface area of 310.0906 m2/g.

Modelling and finite element analysis of turning tables of micro-controller based versatile machine tools desktop learning module

The general-purpose engine lathe is the most basic turning machine tool. As with all lathes, the two basic requirements for turning are a means of holding the workpiece while it rotates as well as a means of holding cutting tools and moving them relatively to the workpiece. In this paper, we present the results of finite element analysis (FEA) performed to investigate nature of stress and their distribution at optimum point along the two turning tables of a micro-controller based versatile machine tool desktop learning module. Commercial Autodesk Inventor was used to create both three-dimensional (3D) and 2D models as well as performing simulation. Dynamics simulation generated the motion load expected to act on the tables when used for real-life operation which were in turn used to perform the FEA. The motion of the DC stepper motor driving the tables and other parts of the module is designed to be controlled by programmable chips. Before creating FEA simulation for the tables, numerical divergence were prevented by varying the mesh settings to obtain the settings at which the results of the analyses converges which was obtained at 0.03 average element size and 0.04 minimum element size. Finite element analysis carried out on the tables shows that aluminium alloy 4032-T6 chosen will serve in the fabrication of physical prototype. FEA revealed the nature and level of stresses that will be experienced on the tables, it also revealed region where these stresses will concentrate on them. The analysis also estimated the expected weight of the turning tables 1&2 to be 1.23536 and 0.257182 kg respectively and show that the minimum factor of safety was constantly 15 ul within the tables which means that they will not fail during operation.

Waste to wealth: A case study of empty water sachet conversion into composite material for automobile application

Efforts have been made to turn empty water sachet (commonly called pure water nylon), palm kernel shell and iron filings, which are all wastes released into the environment from different sectors of production in Nigeria into a useful material of good physical and mechanical properties. These wastes, especially the empty water sachet, pose a great challenge on the effort of achieving a clean and safe environment, mostly by their contribution to flooding during the rainy season. A recycling aimed research was carried out, making use of these materials to produce a new composite material and proffer suggestions for the possible use of the newly developed composite material. The empty water sachet was used as a matrix, which was reinforced by carbonized palm kernel shell particulate and iron filings. The percentage composition of iron fillings was maintained at 5%wt, while that of palm kernel shell ash was varied from 5%wt - 20%wt at an interval of 5%. The composites were compounded and compressively moulded...

Performance Characteristics of a Gasohol Fueled S.I Engine.

Ethanol is a renewable fuel which has the added advantage of improving performance in typically knock-limited operating regions due to the higher octane rating of the fuel. Ethanol was synthesized from groundnut seeds using fermentation method. An experiment was then designed to run a gasoline engine. In this work, the effect of ethanol addition to gasoline on the performance characteristics of a spark ignition engine at various speeds was established. Gasoline was blended with 20 - 80% of the extracted ethanol in an interval of 20%. Results of the engine test indicated that blending ethanol in a proportion of 40% with gasoline can be used as a supplementary fuel in modern spark ignition engines as it is expected to achieve optimum performance on the engine.

Studies on Morphological and Thermal Properties of Low Density Polyethylene/Maize Cob Ash Particulate Composite.

A major problem of reinforced composites is that the interfaces between the fiber and matrix become a limiting factor in improving mechanical properties. The effects of reinforcement on the thermal and morphological characteristics of the low density polyethylene/maize cob ash particulate composite are studied. Morphology of the maize cob ash by scanning electron microscope (SEM) with energy dispersive system (EDS), revealed that the maize ash particles were solid in nature but irregular in size. The EDS scan reveal that the microstructure for the maize cob ash consists of only carbon, silicon, oxygen, aluminium and calcium (C, Si, O, Al, Ca). The incorporation of the maize cob ash particles into the recycled low density polyethylene (RLDPE) matrix increased the thermal decomposition temperatures and the residual yields of RLDPE/MCSp composite, and this enhancing effect was more pronounced at higher heating rate. This result indicated that the presence of maize cob particles (MCSp) could lead to the stabilization of RLDPE, resulting in the enhancement of the thermal stability of RLDPE/MCSp composite.