Open Access Original Research Article

AC Analysis of Differential Active Balun Topology

Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 1-5
DOI: 10.9734/jerr/2020/v10i417043

The current manuscript aimed to study a differential active balun circuit in terms of the small-signal analysis, implemented in a standard 90-nm complementary metal-oxide semiconductor (CMOS) technology. Small-signal or alternating current (AC) response or frequency response of the active balun determines the maximum frequency of operation and the effective bandwidth of the circuit. With the analysis, the active balun circuit could be modeled and designed to achieve gain or attenuation at the desired frequency of operation. Design tradeoffs are inevitable and are carefully considered in the analysis and design. Eventually, the differential active balun design achieved a gain difference better than 1 dB and a phase difference of 180°±10° or better at the frequency of operation of 5.8 GHz, comparable to previous designs and researches.

Open Access Original Research Article

Gis-based Analysis of Water Quality Parameters of Groundwater with Proximity to Onsite Wastes Pits in Vom Community of Jos South, Nigeria

R. E. Daffi, M. I. Alfa, E. S. Ibrahim

Journal of Engineering Research and Reports, Page 6-18
DOI: 10.9734/jerr/2020/v10i417044

Water quality assessment is an important part of environmental quality management especially in groundwater resources located close to sources of contamination. This study involved the assessment of groundwater quality for hand dug wells at locations with proximity to pit latrines in Vom community, Plateau State, Nigeria and the use of GIS for data analysis. Water samples were collected from six (6) locations in a small area to assume possible interaction between the water in the sampling wells, the maximum distance between any two points being 100 m and the minimum distance being 22 m. Eleven (11) physical, bacteriological and chemical parameters were analyzed for the water samples. The results were compared with World Health Organization and Nigerian Standard for Drinking Water Quality standards. The chemical parameters in the samples tested met the WHO and NSDWQ limits with the exception of pH which was slightly acidic for four samples. The results also showed that E. coli was found in all the samples tested. This may be attributed to the proximity of the wells to pit latrines. The results obtained from laboratory analyses were inputted into a GIS database in ILWIS 3.8 where the variation maps were developed and also classified maps for each of the parameters based on whether they meet WHO standards or not. The classified maps were all overlaid in GIS to develop the groundwater quality information map where any point highlighted gives information on the parameters for that point. This makes the retrieval of water quality parameters easy and also the comparison of the parameters with respect to location. Treatment of the groundwater with chemicals like soda ash and chlorine are recommended before consumption. It is generally recommended that wells should not be located in close proximity to onsite underground wastes disposal pits. Government should provide sufficient potable water for the Vom Community.

Open Access Original Research Article

Wafer Thinning Process and Its Critical Manufacturability Requirements

Bryan Christian S. Bacquian

Journal of Engineering Research and Reports, Page 19-25
DOI: 10.9734/jerr/2020/v10i417045

Wafer Thinning as a major semiconductor process steps to attain miniaturization of Integrated Circuit or IC. Wafer back grinding up to 70 µm thickness is considered critical due to its fragility. The paper will discuss the definition and establishment of critical equipment check items to lessen the risk of breakage. Equipment covered was an inline wafer back grinding and wafer mounting. The research has used a qualitative approach by applying process mapping to identify critical sub-process steps. Thereafter, the results show the establishment of critical equipment subprocess steps such as grinding, lamination and de taping. Foreign material and alignment control are considered areas for improvement and have incorporated the control at the equipment preventive maintenance. After all the evaluation, wafer thinning process was successfully released and proliferated from development to manufacturing.

Open Access Original Research Article

Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

S. A. Okaiyeto, Y. A. Unguwanrimi, S. I. Ogijo, B. J. Jonga, A. M. Sada

Journal of Engineering Research and Reports, Page 26-35
DOI: 10.9734/jerr/2020/v10i417046

This research work was carried out to provide local farmers with on-farm solar dryers to minimize post-harvest losses of vegetables. Two dryers (Mixed mode and Indirect mode on-farm solar dryers) were constructed using locally available materials. The dryers basically consist of a blower, a collector area and a drying chamber. Aluminum sheet is placed inside the collector which serves as the absorbing material. An electrical axial fan was placed before the air duct to supply air responsible for forcing heated air to blow over the vegetables to be dried. Incorporated in the drying chamber are trays which provide a platform where the products to be dried were spread evenly. Transparent polythene material of 0.2 mm thickness with wooden frame was used as cover for the dryers. The dryers were evaluated to determine drying time and performance efficiencies, using Baobab leaves, Tomato and Okra slices as test crops. Collected data were analyzed using Statistical Analysis Software (SAS). The effects of variation of the independent factors were verified using Analysis of variance (ANOVA) at 1% and 5% levels of significant. Mean separation was carried out on significant factors using Duncan Multiple Range Test (DMRT). The results obtained showed the performance of the developed dryers, which indicates that drying time of mixed mode on-farm solar dryer stood at 56 hrs and 46 hrs while that of the indirect mode dryer was 76.67 hrs and 57 hrs and that of open sun drying was 154 hrs and 127 hrs for tomato and okra slices respectively. Results obtained showed that average system drying, energy collection and pick up efficiencies for the three test crops were 16.35%, 21.1% and 8.05% for mixed mode dryer respectively and 28.63%, 45.3% and 0.3% for indirect mode dryer, respectively. From the results obtained the mixed mode dryer dried all the products faster while indirect mode has superior energy efficiencies.

Open Access Original Research Article

Critical Insights in the Application of Convection and Pressure Curing in Eliminating DAF Voids

Bryan Christian S. Bacquian, Rennier Rodriguez, Edwin M. Graycochea

Journal of Engineering Research and Reports, Page 36-42
DOI: 10.9734/jerr/2020/v10i417047

The absent of reliable production controls for Die Attach Film (DAF) voids detection allowed defect escapee for Ball Grid Array (BGA) devices using non-conductive film material leading to gross assembly rejection and customer complaints. This paper presents the evaluation of pressure curing as an alternative to the convection curing in die attach process with additional capability to eliminate the DAF voids on non-conductive films. Through Analysis of Variance (ANOVA) analysis, green peeling test, Scanning Acoustic Microscope (SAM), cross section analysis and reliability test performed between samples arrives to the conclusion that pressure oven has a significant impact in die shear strength improvement and DAF voids elimination with positive response in reliability requirement. The result of the study improves the assembly flow and production control of BGA devices through the transition of convection to pressure curing technology.