Open Access Original Research Article

Tool Setup Improvement for Package Scratch Mitigation at End-of-Line Process

A. Sumagpang Jr., F. R. Gomez, R. Rodriguez

Journal of Engineering Research and Reports, Page 1-5
DOI: 10.9734/jerr/2020/v12i317079

With new and continuous semiconductor technology trends, challenges in assembly manufacturing are inevitable. This paper focused on the elimination of assembly defects particularly package chip-out and scratch at the singulation end-of-line (EOL) process of a semiconductor device.  Simulation using computer-aided design (CAD) tools, actual process replication, and validations were done, eventually verifying and replicating the desired defect signatures. Singulation tool setup of the package was improved and a standardized tool setup was established based on the simulation and actual validations, resulting to at least 90% improvement in assembly EOL process parts per million (ppm) reduction.

Open Access Original Research Article

Evaluation of the Corrosion Inhibitive Properties of Three Different Leave Extracts on Mild Steel Iron in Sulphuric Acid Solution

Gabriel N. Chukwueze, Christian O. Asadu, Chijioke E. Onu, Innocent S. Ike

Journal of Engineering Research and Reports, Page 6-17
DOI: 10.9734/jerr/2020/v12i317080

The inhibitive ability of pawpaw, neem and curry leaf extracts on corrosion of mild steel in sulfuric acid solution were investigated in this work. The extracts obtained from their respective leaves, were characterized to determine their phytochemical constituents as well as functional groups present using Fourier Transform Infrared Spectroscopy (FTIR) technique. Weight loss techniques was employed to evaluate the corrosion inhibition efficiency of the leaf extracts. The Scanning Electron Microscopy (SEM) was used to study the morphology of the mild steel before and after corrosion experiments. The process factors studied was exposure time, concentration of leaf extracts (inhibitor) and temperature. The results revealed that the phytochemical constituents of the leaves are capable of inhibiting corrosion due to high concentration of tannins which is responsible for the corrosion inhibition of mild steel. The rate of corrosion decreased with increase in the concentration of the extracts while the inhibition efficiency increased with increase in the concentration of the extracts. Scanning Electron Microscopy (SEM) revealed that the corroded mild steel in the presence of the extracts had smoother surfaces than corroded mild steel in the absence of the extracts. Also, neem leaf extract demonstrated higher potential as corrosion inhibitor than pawpaw and curry leaf extracts.

Open Access Original Research Article

Numerical Modeling of Biological Oxygen Demand (BOD5) Load in Apa Mmini Stream

Ogbebor Daniel, Nwaogazie L. Ify, Momoh O. L. Yusuf, Ndekwu B. Onyedikachukwu

Journal of Engineering Research and Reports, Page 18-24
DOI: 10.9734/jerr/2020/v12i317081

Aim: The study aimed at utilizing finite element modeling approach for extrapolation of BOD5 along the longitudinal length of the stream.

Study Design: The linear element method was used for analyzing the Biological Oxygen Demand (BOD) transport along the longitudinal length of the stream using the Advective dispersive equation (ADE) as the governing equation.  In this study, it was assumed that dispersion was negligible.

Methodology: The BOD5 transport within the stream was modeled using finite element approach. The equation for the stream water pollution modeling was used and the descriptive variables are described as; D is the dispersion coefficient, C is the unknown or state variable (concentration of pollutant or dissolved salt), V is the velocity or convection parameter, k is the applied source or sink and t is the time coordinates.

Results: Prediction results of the finite element model showed that BOD5 decreased downstream from the point of slaughterhouse effluent expulsion. It was observed that both the observed and predicted values of BOD5 correlated strongly with a correlation coefficient of 0.9686. The decrease in BOD5 downstream proves that there is a low rate of re-aeration of the stream; hence the effluent still exceeds the FMEnv recommended standard of 50 mg/l as it travels downstream along the stream profile. The prediction discloses that the river is highly polluted for long stretch of the watercourse, thus implying that selected system of treatment method must be put in place.

Conclusion: Finite element modeling approach was utilized for the extrapolation of BOD5 in Apa Mmini stream. The outcomes of the simulation showed that the Apa Mmini stream is highly polluted with BOD5 of 111.8 mg/l which is far above the FMEnv recommended standard of 50 mg/l.

Open Access Original Research Article

Wafer Saw Process Optimization for Die Chipping Mitigation on Extremely Small Leadframe Package

A. Sumagpang Jr., F. R. Gomez, B. C. Bacquian

Journal of Engineering Research and Reports, Page 25-29
DOI: 10.9734/jerr/2020/v12i317082

The paper focused in addressing the silicon die chippings defect at the wafer sawing process of an extremely small semiconductor package. In-depth potential risk analysis and Pareto diagram were done to identify the top reject contributors and eventually resolve the issue. A comprehensive design of experiment (DOE) was done and validation of the solution was employed to formulate the effective corrective actions. Results revealed that die chippings were addressed by optimizing the wafer sawing process through enabling the dressing, pre-cut and step-cutting modes. Ultimately, an improvement of 95% for die chippings reduction was achieved.

Open Access Original Research Article

Environmental Impact of Open Burning of Municipal Solid Wastes Dumps in Parts of Jos Metropolis, Nigeria

R. E. Daffi, A. N. Chaimang, M. I. Alfa

Journal of Engineering Research and Reports, Page 30-43
DOI: 10.9734/jerr/2020/v12i317083

Refuse dumpsites are found scattered within and outside cities in Nigeria and the open burning of these dumps is a common practice mainly as a waste and odour reduction measure. Open incineration of wastes emits dangerous gases into the atmosphere. The environmental and public health hazards related to open burning of wastes dumps have often been overlooked in most parts of Nigeria and there is limited documentation on this for the study area. This study is aimed at investigating the environmental effect of the burning of open refuse dumps at five locations within Jos Metropolis, Nigeria. Air quality in and around the study area were measured. The results showed that the oxygen levels for all the locations for the different conditions tested ranged between 14.2% and 17.5%. This showed that whether the dumpsites were burning or not the oxygen levels within the vicinity were below the comfortable level of 19.5%. CO levels ranged between 2ppm – 9ppm with the maximum value of 9ppm measured at Apata when the refuse containing some plastics was burning. The values of CO may not be significant but the duration of exposure may make a difference on public healthas most of the dumpsites are located within residential and commercial areas. CO2 values, which ranged between 361ppm to 700ppm, are all higher than standard acceptable levels of 350ppm. The implication is that burning refuse in the open increases the quantity of CO and CO2 in the atmosphere which will likely be of adverse health implication to the residents living close to such areas. It can be concluded that existence and burning of open refuse dumps contributed to the increase in values of air quality parameters measured around the dumpsites. To avert the harmful effects of indiscriminate dumping and burning of solid wastes within residential, commercial and other areas, it is recommended that there should be improvement in solid wastes management in Jos city and environs among other necessary measures.