Abstract: This paper addresses the problem of capturing nondominated points on convex Pareto frontiers, which are encountered in invex multi-objective programming problems. An algorithm to find a piecewise linear approximation of the nondominated set of convex Pareto frontier are applied.

Abstract: In this work, a single zone compression ignition engine cycle model is used to predict the cycle performance of a diesel engine for the cases of using diesel fuel blends of 20, 40, 70, 100 %, unheated jatropha oil (J100) and preheated jatropha oil at a temperature of 90°C (PHJ90). The apparent fuel burning rate could be expressed as the sum of two components, one relating to premixed and the other to diffusion burning. A computer code for the cycle model has been prepared by MATLAB program to perform numerical calculations. The effect of load variation on peak cylinder pressure, specific fuel consumption and thermal efficiency is analyzed. An experimental investigation has been carried out on a diesel engine fuelled with B20, B100, PHJ90, J100 and diesel fuels. The relative error of cylinder pressure between theoretical and experimental data for diesel fuel, B20, B100, PHJ90 and J100 is less than about 4, 5, 1, 4 and 4%, respectively. It was observed that there is a good agreement between simulated and experimental results, these results indicate that the assumptions of the model are reasonable.

Abstract: Wind Energy has become one major renewable energy resource being harnessed to produce electrical energy. Countries who have achieved success include China, Germany, USA, Spain, India, Egypt, Morocco, etc. Plans are afoot in many countries to make increases in current levels of electricity production from wind. Actual wind speed measurements made on the ground in the past at several locations show some promise in Ghana. Ghana as a country has the capacity to generate large-scale power from wind, and as such, deliberate efforts should be made to tackle the country’s energy problems partly with wind energy by installing and gradually increasing wind power supply capacity. This paper reviews and integrates the scattered past and present wind power-related activities in Ghana and brings them under one roof. This paper again identifies some lessons from the activities of the global top 5 successful countries which provide a rich mine of information for policy makers and stakeholders in the energy sector of Ghana. A technical perspective on the way forward for Ghana’s energy future is also presented in this paper.

Abstract: The genus Thymus (Lamiaceae) is widely distributed worldwide and includes a vast group of aromatic plants that contain metabolites with reported antibacterial, antifungal, and pesticidal activities. The structural variability of these compounds, together with their biological activities, may contribute to biological efficacy. Therefore, two sampling methods for the detection of volatile constituents, solid phase microextraction (SPME) and supercritical fluid extraction (SFE) were compared. Parameters used to evaluate the SPME and SFE extraction methods include fibers, extraction time and temperature for SPME, and extraction pressure and time for SFE. A total of 59 compounds were identified by gas chromatography/mass spectrometry (GC-MS), and the results were compared. The SFE method requires expensive and specialized instruments, therefore, the SPME method with its low cost, speed, and simplicity is superior for the extraction of volatile constituents in Thymus vulgaris L. Volatile components were mainly aliphatic hydrocarbons (alcohols, aldehydes, and ketones) and terpenes, which are known for their biological properties and antimicrobial activities.

Abstract: Hypertext Transfer Protocol (HTTP) is a protocol that belongs to the application layer of the OSI model for collaborative, distributed and hypermedia information systems. Hypertext Transfer Protocol gets access to information through Transfer Control Protocol and Internet Protocol in an easy way. It is a stateless protocol with features like persistent connection and pipelining during the communication between client-server. This paper aims to analyze hypertext transfer protocol: its concepts, communication, bit level description and analysis of the recording for HTTP captured data by WireShark. It aims to analyze in details a communication between the client and the server where the client transfers or receives a large amount of data to the server.

Abstract: This paper shows the design of a broadband low noise amplifier (LNA) for ultra-wideband (UWB) applications. The proposed LNA uses cascode configuration technique followed by an inductive inter-stage network to realize the flat gain throughout the UWB band. The inductive inter-stage network is cascaded to a common source amplifier with a shunt feedback resistor for further gain flattens. The proposed LNA is designed in the frequency range 6-9 GHz, with a peak gain (S21) 12dB and input return loss (S11) -10 dB. Its noise figure (NF) is less than 2.5 dB, input third-intercept point (IIP3) of 5 dBm, 1-dB compression point (P1dB)of -5.85dBm. The proposed LNA is designed using UMC 130nm CMOS technology and consumes 4.8 mW from 1.2V power supply.

Abstract: Tin and its alloy as solders materials is prone to whiskers growth during its application. Lead free solder materials (Sn-Cu) has been pressed to see how crystallographic parameter, micro strain, crystallite size and texture changed. X-ray diffraction pattern of the samples were obtained by means of X ray diffractometer. Rietveld refinement of the diffraction pattern show that pressure influenced crystallographic parameter, crystallite size, micro strain and texture. It is expected that by knowing which crystallographic plane affected significantly, whiskers growth through this plane.

Abstract: The aim of this research was to improve soldering properties of eutectic SnCu0.7 binary solder alloy. It is considered as one of the alternates for Sn-Pb solders with melting temperature is 227 ºC. To verify this aim, effect of adding bismuth\ or bismuth- indium on structure, wetting behavior, melting temperature, electrical resistivity, elastic modulus and internal friction of tin-copper eutectic alloy has been investigated. Matrix microstructure such as lattice parameters, unit cell volume and formed crystal structure of Sn99.3Cu0.7 alloy changed after adding bismuth or bismuth-indium. Melting temperature and contact angle of Sn99.3Cu0.7 alloy decreased after adding bismuth or bismuth- indium. Electrical resistivity of Sn99.3Cu0.7 alloy increased but elastic modulus decreased after adding bismuth or bismuth- indium. The Sn79.3Cu0.7Bi20 and Sn69.3Cu0.7Bi20In10 alloys have best properties as a lead free solder alloys for electronic industrial applications.

Abstract: A hybrid technique consisting of moving least square differential quadrature and finite difference methods is employed to examine bending problems of irregular composite plates. Based on a transverse shear theory, the governing equations of the problem are derived. The transverse deflection and strain rotations of the plate are independently approximated with moving least square approximations. The partial derivatives of these quantities, at the interior nodes, are approximated using finite difference approximations. The obtained results agreed with the previous analytical and numerical ones. Further a parametric study is introduced to investigate the effects of elastic and geometric characteristics on behavior of the transverse deflection and stress field quantities.