Evaluation of Frictional Heat and Oil Cooling Rate in Mechanical Contact Due to Debris Formation

This paper evaluated experimentally, the amount of frictional heat generated in a Mitsubishi main journal bearing and the cooling performance of the lubricating oils A, B and C. The test rig used in this experiment is a mechanical apparatus that consists of mechanical drive, metal support, bevel gear, a rotating shaft and a bearing attached at its lower end. When the shaft was rotated by the mechanical drive of power 0.75kw and speed 1440rpm, the frictional force in journal bearing helped to convert the mechanical energy of the drive into frictional heat. The amount of heat absorbed from the surface of the journal bearing by the oil cooled the surface. The cooling rate of the oil was obtained at each time interval. The vibrating movement of the molecules helped to transfer the frictional heat to the lubricant and the calorimeter. This effect caused the temperature of the system to rise. The frictional heat generated at the contact increased linearly with the change in temperature in the mechanical contact which was absorbed differently in the three lubes, depending on their heat capacity and molecular movement. When there was no debris in the contact, the temperature changed within the range of 1.2-1.80C at interval of 3minutes in oil B, 10C in oil C and 0.8-1.20C in oil A. When there was sand debris in the contact, the temperature changed within the range of 2-2.50C at interval of 3minutes in oil B, 1.5-20C in oil C and 20C in oil A. Oil B has the best cooling performance based on the three local lubes used and was equally the most expensive. Mechanical failures like galling, fatigue and surface indentation occurred when the vibrational force (energy) of the molecules were greater than the binding force or energy of the atomic lattice of the bearing

Effect of Particle Sized Clay Extender Pigment on Alkyd Paint Formulations

The effects of particle sizes on the properties of Ihitte-Uboma clay formulated alkyd paints have been studied. The clay particle sizes studied are 75, 150and 300 µm at clay contents 0 – 80 wt. %. Xylene was used as the solvent while TiO2 formulated alkyd paint served as reference alkyd paint in this study. The extender pigments were characterized using X-ray fluorescence and scanning electron microscope. The physic-chemical properties of the extender pigments were determined using ASTM measurements. The properties of the paint samples were evaluated according to ASTM. Results showed that the alkyd paints had higher viscosities which increased with increases in clay contents at the three clay particle sizes investigated. The drying properties of the paints were generally good. The dry film thicknesses of the formulated paints were in the range of 0.29 – 0.38 mm. The formulated paints exhibited moderate settling tendencies at the 75 µm clay particle size when compared with the other particles. There was no mildew formation observed on all the paint samples on exposure to rain and sunlight. Generally, all the paint samples exhibited good resistance to distilled water, 3 % H2SO4, and 3 % Na2CO3. The formulated paint samples were affected on 3 % NH3 immersion which resulted to wrinkles. The improved properties obtained from the clay formulated paints which include thermal and colour stability, viscosity, specific gravity

Modeling and Optimization of Performance of Four Stroke Spark Ignition Injector Engine

The performance of an engine whose basic design parameters are known can be predicted with the assistance of simulation programs into the less time, cost and near value of actual. This paper presents a comprehensive mathematical model of the performance parameters of four stroke spark ignition engine. The essence of this research work is to develop a mathematical model for the analysis of engine performance parameters of four stroke spark ignition engine before embarking on full scale construction, this will ensure that only optimal parameters are in the design and development of an engine and also allow to check and develop the design of the engine and it’s operation alternatives in an inexpensive way and less time, instead of using experimental method which requires costly research test beds. To achieve this, equations were derived which describe the performance parameters (sfc, thermal efficiency, mep and A/F). The equations were used to simulate and optimize the engine performance of the model for various engine speeds. The optimal values obtained for the developed bivariate mathematical models are: sfc is 0.2833kg/kwh, efficiency is 28.77% and a/f is 20.75. Keywords: Bivariate models, Engine performance, Injector engine, Optimization, Performance parameters, Simulation, Spark ignitio

Experimental Investigation on Effect of Head and Bucket Splitter Angle on the Power Output of A Pelton Turbine

This paper investigates through experiment, the effect of head and bucket splitter angle on the power output of a pelton turbine (water turbine), to improve the power generation by the use of efficient Hydro-electric power generation systems. Experiments were conducted on pelton turbine head conditions, high head and low flow with increased pressure delivered more energy on the bucket splitter which then generates a force in driving the wheel compared to the result obtained from low head and high flow operating conditions. The power output was maximum at 23o splitter angle followed by 21o, 15o, 10o and 3o using varied turbine speed (1700, 1400, 1200 and 1000rpm). The force generated by the bucket due to the splitter was increased as the turbine speed was increasing. The force generated by the bucket was increased (0 to 0.38N) due to the energy delivered to the wheel by the head, the turbine output increases from (0 to 7.47kW) which influences the output. This increase in the power output was as a result of their head conditions and the bucket splitter angle

Omics-based molecular techniques in oral pathology centred cancer: Prospect and challenges in Africa

: The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratifcation of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the profciency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among diferent human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences