Open Access Original Research Article

Effect of Cutoff Grade and Stripping Ratio on the Net Present Value for Hamama Gold Project, Eastern Desert, Egypt

Helal H. Hamd_Allh, M. R. Moharram, Mohamed A. Yssin, M. A. Gouda, A. Kh. Embaby

Journal of Engineering Research and Reports, Page 1-8
DOI: 10.9734/jerr/2020/v11i417064

This paper represents an attempt to examine the effects of Cutoff Grade (COG) and Stripping Ratio (SR) on the Net Present Value (NPV) for the proposed gold mine in  Hamama area, hence to attain best operating condition corresponding to the optimum COG and SR in the proposed gold mine. Discount Cash Flow (DCF) model has been established to calculate NPV by taking the change in the COG and SR into account.  This detects the effects of COG and SR on the NPV of this project. The actual production and cost data of Sukari Gold Mine (SGM) of Egypt have been taken as an indicator in creating DCF for the proposed gold mine where maximum NPV results proved the optimum COG and SR.

Open Access Original Research Article

Inhibition of Mild Steel Corrosion in 0.25 M H2SO4 Using Tetracarpidium conophorum Shell Extract

N. C. Ngobiri, K. N. Kikanme

Journal of Engineering Research and Reports, Page 19-24
DOI: 10.9734/jerr/2020/v11i417066

The capacity of aqueous Tetracarpidium conophorum Shell (TCE) Extract to inhibit pipeline steel corrosion in 0.25 M H2SO4 acid was investigated using weight loss and Uv-visible spectroscopy techniques. The phytochemical components of Tetracarpidium conophorum were identified using GC-MS analysis. The results obtained shows that aqueous Tetracarpidium conophorum shell extract decreased the corrosion rate, while the corrosion inhibition efficiency increased with increase in exatract concentration. The Uv-visible spectra indicated a chemical interaction between the TCE molecules and atoms of Iron on the pipeline steel surface, while GC-MS analysis showed the presence of organic compounds with hetero-atoms for adsorption on the steel surface.

Open Access Original Research Article

Dicing before Grinding: A Robust Wafer Thinning and Dicing Technology

Bryan Christian S. Bacquian

Journal of Engineering Research and Reports, Page 25-34
DOI: 10.9734/jerr/2020/v11i417067

The never-ending trend for package miniaturization has been driving the semiconductor industry to the brink of technology. Hence, development of new technologies is necessary to cope up with the demand for advance and aggressive process capabilities.

The paper is all about the challenges in developing and installing a robust 50 µm wafer thinning and dicing capability in ST Calamba. As silicon wafers are grinded thinner, the more it becomes sensitive to mechanical stress and vibration. The conventional mechanical dicing process induce a lot of mechanical stress and vibration during the cutting process which oftentimes lead to backside chipping and die crack issues. Backside chippings serves as fracture points at the back of the dice, which significantly reduce its die strength. This dilemma was addressed with the use of a breakthrough technology known as Dicing Before Grinding (DBG).

Open Access Original Research Article

Application of Ultraviolet Treatment for Paper Production - An Engineering Study

Klaus Dölle, Neil Goodman, William Lawrence

Journal of Engineering Research and Reports, Page 35-41
DOI: 10.9734/jerr/2020/v11i417068

Ultraviolet (UV) radiation systems are a common method of inactivating bacteria in municipal water treatment but has not been applied in a paper mill operations. Determining the feasibility of installing such a system is the purpose of this report. Directly treating a starch solution of sufficient concentration proved impossible as the transmittance required was far too low. Water used in the onsite water recycling facility’s cooling towers had a transmittance over 90% and so was very treatable. Lab scale testing with a designed 15 liter laboratory benchtop ultraviolet treatment system showed that UV treatment can reduce the aerobic bacteria count by two fold for up to 24 hour of operation and significantly lower results for 48 and 72 hour of operation. Therefore, UV treatment can be considered a valuable process for the treatment of cooling tower water.

Open Access Review Article

Buoyancy-Induced MHD Stagnation Point Flow of Williamson Fluid with Thermal Radiation

J. O. Ouru, W. N. Mutuku, A. S. Oke

Journal of Engineering Research and Reports, Page 9-18
DOI: 10.9734/jerr/2020/v11i417065

Flow of fluids subjected to thermal radiation has enormous application in polymer processing, glass blowing, cooling of nuclear reactant and harvesting solar energy. This paper considers the MHD stagnation point flow of non-Newtonian pseudoplastic Williamson fluid induced by buoyancy in the presence of thermal radiation. A system of nonlinear partial differential equations suitable to describe the MHD stagnation point flow of Williamson fluid over a stretching sheet is formulated and then transformed using similarity variables to boundary value ordinary differential equations. The graphs depicting the effect of thermal radiation parameter, buoyancy and electromagnetic force on the fluid velocity and temperature of the stagnation point flow are given and the results revealed that increase in buoyancy leads to an increase in the overall velocity of the flow but a decrease in the temperature of the flow.