Effects of Mixed Alkaline Earth Oxides in Potash Silicate Glass

The aim of this work is to investigate the effects of mixed alkaline earth oxide in potash silicate glasses with regards to their physical properties. More recently; there has been an increase in the demand for light weight glasses which retains their physical and chemical properties for both domestic and industrial applications. The effect of mixing Alkaline earth oxide in potash silicate glass on their density, thermal properties and other physical properties has been studied. As for the method used, raw materials were collected, batch calculations were made, and the batches (A and B) were melted in an electric furnace to produce blocks of glasses. Three pieces were cut out of the block of glasses, grinded, polished and re – annealed. The re – annealed glasses were measured, for their densities, thermal, toughness, hardness, elastic moduli and brittleness. More so micrographs of the indented glasses were taken.Results showed that mixed alkaline effect (MgO:CaO) is minimal on the densities of the A glass series while the addition of (MgO:BaO) to the glass matrix of the B glass series increased its density. The crystallization temperatures of the glasses were influenced by the addition of alkaline earth oxides. The hardness and brittleness of both glass series (A and B) decreases with increasing magnesia fraction of the total alkaline earth oxide. The fracture toughness increases as the magnesia fraction of the total alkaline earth oxide increases. Conclusively, glasses of different properties depending on the desired requirement can be obtained by varying the known quantities of mixed alkaline earth oxides.http://dx.doi.org/10.4314/njt.v34i4.1

PERFORMANCE EVALUATION OF A PILOT PARAPLEGIC CENTRICITY MOBILITY AID

This paper was aimed at evaluating the functional characteristics of a developed mobility aid for paraplegics in Benin City, Nigeria using their anthropometric data. These functional characteristics were compared with the conventional motorised wheel chair found in most city centres in Nigeria under the same condition. The method adopted in establishing the differences in the developed mobility aid and the conventional types include the use of variables such as, the time required to board, time to complete a 100 meters distance, fuel consumption rate and the subjects’ operational postural angles. The values obtained from these findings were computed and compared with the values obtained from the conventional wheel chair under the same operational conditions. Consequently, the values obtained were subjected to statistical analysis using the Van der Waerden normal score test and the Wilcoxin’s signed rank test. The result of the test showed a remarkable improvement in fuel consumption rate, ease of use and other functional characteristics of the developed mobility aid over the conventional wheelchair available to paraplegics in Nigeria. From the result, it is evidential that the developed mobility aid meets the requirements of adult paraplegics in Nigeria. The use of this mobility aid will make them lead a normal way of life and contribute meaningfully to national growth and development. http://dx.doi.org/10.4314/njt.v35i1.

ANALYSIS OF COCONUT ETHYL ESTER (BIODIESEL) AND FOSSIL DIESEL BLENDING: PROPERTIES AND CORROSION CHARACTERISTICS

The effect of biodiesel and its blends synthesized from coconut oil (CNO) via alkali catalyzed transeterification on the key fuel properties and corrosion characteristics of copper were investigated. The transesterification of the CNO via ethanol in the presence of potassium hydroxide was performed and the resulting coconut oil ethyl ester (COEE) was blended with fossil diesel (B0).  The fuel properties such as density, kinematic viscosity (KV), pour and cloud points (PP and CP, respectively) and American Petroleum Institute of Gravity (API) of B0, COEE-diesel blend (B50) and COEE (B100) were characterized and compared with that of ASTM D6751 and EN14214 standards. Static immersion tests were conducted by exposing copper coupons toB0, B50 and B100 at different temperatures (50, 65 and 80 oC) for 5 days.  Corrosion rates of copper in these fuels were determined by weight loss method. Also, during the period of investigation, these fuels were analyzed by measuring total acid number (TAN). The results showed that the density, KV, PP and CPincreased while the API gravity decreased as the percentage of the biodiesel in the blend increased. The highest corrosion rates for copper at the end of the investigation were 0.054, 0.0954 and 0.139 mpy in B0, B50 and B100, respectively. The minimum TAN (0.17 mg KOH/g) and maximum TAN (0.62 mg KOH/g) were observed in B0 and B100 containing copper, respectively. http://dx.doi.org/10.4314/njt.v35i1.1