Journal of Engineering Research and Reports

This study was carried to determine the level of heavy metals toxicity in swampy forest of Isoko South, Delta State, Nigeria. Sediments samples were collected from nine spatial points, within the swampy forest of Enwhe community of Delta State, Nigeria. The study area contained clusters of illegal crude oil refineries, before they were destroyed by the Nigeria military, during the first quarter of 2020. A total area of 1 km² of the swampy environment was covered in this study. Six toxic heavy metals (Cu, Zn, Cr, Cd, Pb, and Ni) contents, in the sediments were determined in accordance to international approved standards. The results revealed that the activities of the illegal refineries located in the study area, significantly increased the heavy metals toxicity in the sediments.  When compared with the results obtained from a reference point, the concentrations of the heavy metals were significantly higher, across the study area. Within the study area, spatial points B and D sediments contained the highest heavy metals concentrations. In addition, the study revealed that contamination factor of the sediments ranged between moderate and high degree of heavy metals contamination. This portrayed the potential ecological risks of the illegal refineries activities, to the environment of the region. Therefore, if these illegal refineries activities are allowed to continue unabated, they will cause a serious ecological risk to the Niger Delta region ecosystems.

This paper presents the application of an innovative design of wirebond process plate during wirebonding process of thin semiconductor carrier such as the pre-encapsulated leadframe. The implementation of the specialized process plate aims to improve the conventional method of wirebonding from panel type to single-row design to reduce the occurrence of warpage on thin leadframes. In this study, an 85% reduction for warpage level is achieved after the introduction of the new design of process plate. Future works could use the improved process plate design for devices of similar configuration.

The maximum likelihood estimation method is an effective technique for estimating the parameters of the Weibull distribution. However, it is an arduous task to compute the parameters of the Weibull distribution using numerical methods, hence; various reliability software packages have been developed to address this difficulty. In this study, an attempt is made to obtain the estimates of three-parameter Weibull distribution through the application of Weibull analysis software TPC Windchill Quality Solutions 11. The study involves the analysis of the failure times of ten identical gas turbines blades over a period of ten years. From the results obtained, it was found that the gas turbine blades were in their wear-out period. The results obtained in the study were compared with Weibull analysis software Minitab 19 and the values of the Weibull estimates obtained were found to be close. This shows that the software is suitable for the parameter estimation of three-parameter Weibull distribution.

This paper presents an experimental analysis of heat transfer using different shaped fills in a counter flow induced draft cooling tower. The main objective is to determine and compare the characteristics of the cooling tower using newly shaped (splash and film) fills and the regular used fills. The newly shaped fills are inverted U-shape cross-sectional splash fill and film fill with ripple plates. The obtained results show that the performance is affected by the type and arrangement of the fills. The modified splash fill has increased the wetted surface area of fill within the same volume compared to regular fills. The film fill with ripple plates has been used     such that water from the distribution device ran down on both surfaces of each ripple plate. By the arrangement of ripple plates, cooling loss by premature dropping off of water has been avoided. Performance factors like range, approach, effectiveness, cooling capacity, evaporation loss, percent loss are calculated from collected data for newly shaped fills, and regular shaped fills. It is observed that range, effectiveness, and cooling capacity increases with both newly shaped fills. When ripple plated film fill is used; range, effectiveness, and cooling capacity is found highest among the different shape of fills used in this study. At the same time evaporation loss and percent loss are found lowest for inverted-U shaped splash fill.

In this paper, we study the numerical approach of MHD Casson fluid flow over a permeable stretching sheet with heat and mass transfer taking into cognizance the various parameters present. A set of suitable local similarity transformations are used to non-dimensionalize the governing equations of the present problem. The system of ordinary differential equations are solved numerically by MATLAB bvp4c solver. The effect of the involved parameters on Velocity, Temperature, and Concentration, Skin friction coefficient, Nusselt number and Sherwood number has been studied and numerical results are presented graphically and in tabular form. The numerical results are in good agreement with those of the results previously published in the literature.