Open Access Original Research Article

Comparative Analysis of Mono-Factorial Effects on Compressive Strength of Sandcrete Block Produced at Various Curing Age in the Warm Humid Climate of Nigeria

Ikechukwu Uche Felix

Journal of Engineering Research and Reports, Page 1-9
DOI: 10.9734/jerr/2018/v2i310082

Quality of a composite material like sandcrete block is basically a function of the basic properties of the constituent ingredients, mix ratio relationship and its production characteristics. This study, investigate the effects of change in quantities of the constituent ingredient on compressive strength of sandcrete blocks produced at various curing ages in Owerri Metropolis. Field survey was conducted in the area to determine the production characteristics of the blocks marketed in the area. Based on the prevalent nominal mix ratio of the block, mix design on the constituent ingredients of the block based on box-wilson symmetric composite plan B3was adopted. Results of the strength from each experimental set of the design were used to formpolynomial regression models of blocks cured at various ages. Findings show that the average compressive strengths of the 7-day, 14-day, and 28-day old cured blocks are 1.578 N/mm2, 1.604 N/mm2, and 1.975 N/mm2.Mono-factorial analysis shows that at its respective age of curing, cement and water factors have stronger effect on the strength of the block than sand factor. The nature of their influences is positive, and more linear than quadratic and mutual interaction relationships. The relationship of mutual interaction between the cement and water factors is seen only in the models of the 7-day and 28-day curing ages in the study. Since the strength of the block increases with increase in the age of curing, it therefore confirms the standard practice of 28-day curing age for improved quality of sandcrete block in the industry; as well as recommending mono-factorial analyses on the effects of the independent factors of the mix designed blocks cured age 28-day age, towards optimum composition of the sandcrete mix ingredients for the desired quality of the blocks produced in the study area.

Open Access Original Research Article

Microcontroller Based Electronic Digital Lock with Security Notification

Musa Baba Lawan, Ya’u Alhaji Samaila, Ibrahim Tijjani

Journal of Engineering Research and Reports, Page 1-13
DOI: 10.9734/jerr/2018/v2i310954

Due to the advancement in science and technology all over the world, there is a significant increase in the rate of crime and sophistication in crimes; as a result, it is necessary to ensure the security of one’s self and one’s valuable belongings. The main goal of this paper is aimed at creating an electronic security system capable of detecting an intruder and reporting to security personnel. The design of the microcontroller based electronic digital lock with security notification uses a four-digit pass key for its operation. The operation involves opening the door, closing the door, changing of password and alarm upon wrong password entry. It is important for use in Bank Vaults, Hotels, Offices and can also be used in our homes. The research objectives were achieved with the use of microcontroller which programs the ATMEGA328P microprocessor and interfaces it with all the other components in the circuit. In the end, the circuit was able to activate the relay switches for opening and closing the door in about three seconds, and the alarm sounds when it detects a wrong password. Comparison was made between the conventional traditional lock system and the proposed one. The distinctive feature added is the sliding door, the security notification feature and the password modification in case of a breach in security. The design fulfills the requirements of supporting conventional lock systems eliminating the use of ordinary keys shared among occupants. To demonstrate and evaluate the design, a prototype was developed. As compared to other microcontroller based digital lock, it is easy and it required less hardware. It doesn’t need additional A/D and D/A converter. We can set the password and reset it without using external device and can be easily implemented. The evaluation shows that the design works well, consumes minimal power and is able to unlock a door.Atmega328p Microcontroller was used as the main component of the project.

Open Access Original Research Article

Gilbert-Cell Mixer for WiMAX Applications

Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 1-9
DOI: 10.9734/jerr/2018/v2i310956

Differential implementation is becoming highly popular in Radio Frequency Integrated Circuit (RFIC) design, notably for its high immunity to common-mode noises, acceptable rejection of parasitic coupling, and increased dynamic range. One RF front-end building block that is usually designed as a differential circuit is the mixer. This paper presents a design, study, and optimization of a differential mixer, more specifically the Gilbert-cell mixer (also known as double-balanced mixer) implemented on a direct-conversion architecture in a standard 90 nm Complementary Metal-Oxide Semiconductor (CMOS) process. Operating frequency is set to 5GHz, which is a typical frequency for Worldwide Interoperability for Microwave Access (WiMAX) receiver. Impedance matching was necessary to design and fully optimize the mixer design. The direct-conversion Gilbert-cell mixer design ultimately achieved conversion gain of 11.463dB and noise figure of 16.529dB, comparable to mixer designs from past research and studies.

Open Access Original Research Article

MHD Natural Convection Casson Fluid Flow over a Non-Isothermal Stretching Sheet Embedded in a Porous Medium

B. O. Falodun, M. O. Oke, O. O. Fagbohun

Journal of Engineering Research and Reports, Page 1-16
DOI: 10.9734/jerr/2018/v2i310957

In the present study, Magnetohydrodynamics (MHD) natural convection Casson fluid flow over a non-isothermal stretching sheet embedded in a porous medium is considered. The set of governing differential equations are simplified by similarity variables into coupled ordinary differential equations. The defined stream functions satisfied the continuity equation. Roseland approximation is utilized and the present study is therefore limited to an optically thick fluid. The transformed set of coupled nonlinear ordinary differential equations are then solved numerically via spectral homotopy analysis method (SHAM). Results revealed that the Magnetic parameter (M) reduces the velocity profile but produce a significant increase in the temperature profile. Also, it is observed that increasing the thermal radiation parameter increases the thermal condition of the fluid.

Open Access Original Research Article

Kinetic Study, Modelling and Optimization of Adsorption Processes for Removal of Crude Oil from Contaminated Water using Chitosan-Rice Husk Ash Composite

G. G. Oseke, M. T. Isa, M. S. Galadima, A. O. Ameh

Journal of Engineering Research and Reports, Page 1-10
DOI: 10.9734/jerr/2018/v2i310962

This study was aimed at developing chitosan-rice husk ash adsorbent for the removal of crude oil from contaminated water. Design Expert software 6.06 was used to design the adsorption experiment. The adsorption was tested for Langmuir, Freundlich and Temkin isotherms and the kinetic studies also carried out. The effect of influencing parameters such as contact time, adsorbate concentration, adsorbent dosage and formulation ratio were studied. It was generally shown that adsorption process increased with time and adsorbate concentration and decreased with adsorbent dosage. Models for the prediction of adsorption capacity for the composite was significant with R2 value of 0.8382 and P-value of 0.0017. Optimum conditions were found to be 0.90 wt/wt chitosan/silica ratio, contact time of 5 min, and oil/water ratio of 0.25 v/v, which gave 20.66 g/g sorption capacity respectively. Adsorption isotherm studies of Langmuir, Freundlich and Temkin were carried out for the chitosan-rice husk ash composite. Temkin isotherm best fitted with R2 value of 0.9999. The adsorption capacity of composite from isotherm studies was obtained to be 18.85 g/g adsorbent. The heat of adsorption bT (kJmol-1) obtained from Temkin isotherm study was -48.67 kJ/mol indicating physisorption of adsorbents to the crude oil.  Kinetic studies indicated that the pseudo-second order model suitably described the removal of crude oil by the composite with R2 value 0.9999.