Design and fabrication of a multipurpose railroad hand truck

A multipurpose railroad hand truck comprising mainly of a frame, swinger arm, connecting rod, crank shaft, gears, wheels and brake was designed and fabricated to reduce the cost of material handling in small scaled manufacturing industries. The frame and other major components of the hand truck were fabricated with mild steel bars, shafts and sheets while the guide rail was constructed using 50mm by 50mm mild steel angle bar. The hand truck is hand paddled and requires no prime mover (electric motor, IC engine, etc.), hence incurring minimal operational cost. The hand truck will be used to convey tools, materials and work pieces from one part of the workshop to another on guide rails. Results of its performance test indicated that the hand truck can carry loads up to 250kg. All materials used for the fabrication were sourced locally.Keywords: railroad, truck, paddled, swinger, multipurpos

Determination of Natural Frequencies of a Cantilevered Discontinous Beam with Aligned Neutral Axes: Receptance-Graphical Approach

This work presents a graphical approach to find the natural frequencies of a fixed-free discontinuous Beams with aligned neutral axes based on different boundary condition.  A receptance model is introduced to analyze the problem of discontinuous beams, using the differential equation of motion based on the Euler-Bernoulli beam equation. The natural frequencies equation are obtained from the receptance model. The graphical methods gives the approximate solution, but need a lot of effort on calculation. The solution obtained are compared to the result from experimental model testing. Keywords: Receptance function, discontinuous Beam, Graphical method, natural frequency

End-use energy utilization efficiency of Nigerian residential sector

In this paper, the end-use efficiencies of the different energy carriers and the overall energy efficiency in the Nigerian residential sector (NRS) were estimated using energy and energy analysis. The energy and energy flows were considered from 2006 to 2011. The overall energy efficiency ranges from 19.15% in 2006 to 20.19% in 2011 with a mean of (19.96±0.23)% while the overall energy efficiency ranges from 4.34% in 2006 to 4.40% in 2011 with a mean of (4.31±0.059)%. The energy and energy efficiency margin was 15.58% with a marginal improvement of 0.07% and 0.02%, respectively when compared with previous results. The contribution of the energy carriers to the total energy and energy inputs were 1.45% and 1.43% for electricity, 1.95% and 3% for fossil fuel and 96.6% and 95.57% for bio-fuel. The result shows that approximately 65% of the residence use wood and biomass for domestic cooking and heating, and only a fraction of the residence have access to electricity. LPG was found to be the most efficient while kerosene, charcoal, wood and other biomass the least in this order. Electricity utilization energy efficiency is affected by vapor-compression air conditioning application apart from low potential energy applications. In addition, this paper has suggested alternatives in the end-use application and has demonstrated the relevance of energy analysis in enhancing sustainable energy policies and management and improved integration technique