Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
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Effects of Varying Transmitter Half Power Angle in Visible Light Communication
No full textVisible light communication (VLC) involves sending and receiving information using light as carrier to transmit the information from sender to receiver. One of the most important parameters of a transmitter in a VLC system is the semi angle at half power which is also referred to as the transmitter half power angle. Varying it could affect the amount of light or optical power received at the receiver and depending on the configuration of the transmitters. This can lead to loss of some part of received power. This work investigates how such variation in half power angle can affect average received power by considering separate transmitter arrangements/configuration that can be adopted for VLC based on same number of these transmitters. Six separate arrangements of six transmitters were considered in a line of sight (LoS) indoor VLC scenario. The results were achieved by varying the half power angle between a minimum of 10° and a maximum of 80°. The result showed that different levels of received power were attained at different half power angles for each different transmitter configuration. For instance at a low angle of 10^o, the third configuration had an average received power of 2.8139mW while fourth configuration had an average received power of 2.6700mW which implies the third configuration has a better performance. At a high angle of 80°, average received power for third configuration was 1.2207mW and it was 1.0672mW for the fourth configuration showing that the third configuration still performs better. The third configuration generally outperformed all the other ones. The fifth configuration had a good average received (2.8120mW) at low angle of 10^0 but it gradually became poorer (1.1782mW) at higher angles of up to 80° in comparison to other configurations which indicates this configuration does not perform well at higher half power angles. The findings of the work signified that changing the transmitter configuration can cater for power losses that maybe encountered as a result of varying the transmitter half power angle in a VLC system without giving up so much on uniformity of distribution of the light.
 
Effect of Wild-Vine Powder (WVP) as Admixture in Compressed Lateritic Earth Blocks (CLEB)
Get PDFIn this paper, the effect of wild-vine powder on strength and durability properties of compressed lateritic earth blocks was evaluated through series of laboratory experiments. The wild-vine powder (WVP) used was obtained by crushing roots of wild-vine into smaller particles and then grinding into powder. It was thereafter subjected to chemical composition analysis using standard procedure. The WVP was added to the mixes of the laterite soils at varying percentages of 0, 2, 4, 6, 8, and 10% respectively by weight of the laterite required for the compressed lateritic earth blocks. The mixes were cast in steel fabricated mould of dimension (230mm x 120mm x 100mm) compressed using UTM machine and demoulded using a locally fabricated mould. The samples were thereafter air-dried and subjected to uniaxial compression tests to establish their compressive strength, alongside durability tests to determine their resistance to abrasion and water absorption. The results showed that WVP predominantly contain calcium oxide (44.6%) and potassium oxide (36.1%). The addition of WVP up to 6% in compressed lateritic earth blocks (CLEB) improves the compressive strength, resistance to abrasion, and water absorption for stabilized CLEB-block. The addition of WVP in laterite up to 10% is adequate as it gives compressive strength of 2.21N/mm2 greater than 2N/mm2 specified by NBRRI, 2016, and thus recommended for use in building of low-cost earthen buildings.
 
Development and Design of a Microcontroller-Based Gas Weight and Leakage Detection System
Get PDFThis paper presents the design and development of a prototype system for monitoring gas leakage and weight in residential and semi-commercial. Liquid Petroleum Gas (LPG) installations LPG is widely used as a fuel source, but its leakage can lead to devastating fires, posing a significant threat to life and properties. Traditional methods of gas management based on natural nasal detection and estimation of usage are considered unsafe. The proposed system incorporates the MQ-5 sensor for gas leakage detection and the HX711 IC device for weight sensing. It includes a user alert system with a buzzer and LED for timely notifications of gas leakage and low gas levels. The control system, driven by the ATMega328p microcontroller, receives data from the sensors and triggers alerts accordingly. The power unit utilizes a 3.7-volts amplified lithium polymer battery stepped up by the MT3608. The results show that through week-long testing, the prototype demonstrated its effectiveness in monitoring weight and gas leakage, with constant monitoring of sound, LED, and display readings. This paper offers insights for replication as students projects, and suggests the need for more testing and calibration to ensure safety and the need for IoT-enabled features for smarter deployment and management. Furthermore, the prototype had contributed to promoting safety and preventing accidents in LPG installations by addressing the critical issue of gas leakage.
 
Development of a Manually Operated Sleeve Puller Kit for Reciprocating Type Engine
Get PDFThis work describes design and construction of manually operated sleeve puller kit for removal of piston liners. Piston cylinder sleeves which are firmly fixed in the engine block of many reciprocating engines are normally removed for the purpose of repairs, maintenance and replacement, and is difficult to remove by hammering; hence the need for a puller. To demonstrate the workability of the design, a cylinder sleeve of 100KvA generator was constructed. The components for the device were: frame, screw and base, constructed from grey cast iron, unalloyed free cutting steel and copper alloy materials respectively. The components were constructed using cutting, drilling, rolling and arc welding machine operations. The sleeve puller was tested on a 100KvA parkins generator. The cost of producing the device was N9, 150:00, which was effective compared to similar devices in the market that cost within the range of N15, 000 to N20, 000. From the performance test results obtained, the maximum torque to raise the required load was determined to be 452.898 × 103 N-mm and shear stress of the screw as 23.697MPa which was less than the strength of free cutting steel (56MPa). Buckling criterion was 371.09KN>75KN, transverse shear at the root and body area of the screw are 8.768<19MPa and 10.484MPa<56MPa. A piston sleeve puller was successfully developed. A hydraulic or electrically operated can further be investigate.
 
Modeling Rainfall-Runoff Relations Using HEC-HMS in an Oil Palm Catchment for Double Rain Events in Labu River Basin of Peninsular Malaysia
Get PDFIn order to simulate a single rainfall event that occurred in the Labu catchment on April 7 and August 13, 2015, the HEC-HMS and soil moisture balance models were used. Based on the years that the peat swamp forest was converted into an oil palm plantation, the study plots within the watershed were divided into four plots: 2000, 2002, 2006, and 2010. In this study, two different hydrological models were employed such as the Soil moisture balance model and the Hydrologic Modeling System (HEC-HMS). A rainfall-runoff relationship for the sub-catchment was established using the Hydrologic Modeling System, HEC-HMS, coupled with recorded flow and rainfall data. This relationship was calibrated and then validated before being utilized for runoff estimation. The calibrated streamflow from the soil moisture balance model was compared with the HEC-HMS discharge values, which were used as the observed flow. The results show that the calibrated streamflow in the soil moisture balance model agrees with the observed streamflow data in the HEC-HMS. Following the two rainfall occurrences, the two models' respective Nash-Sutcliffe Efficiency (Ef) values were 0.82 and 0.90 which implies that the observed flow and the predicted flow by the models are correlated and this shows a strong acceptable model performance for model simulation. This also means that the application of the HEC-HMS along with a recorded streamflow data shows the ability of the HEC-HMS model to calculate the streamflow volume in a double storm event at Labu basin
Effect of Loading Rate on Viscoelastic Behaviour of Cassava Roots (Manihot Esculenta Crantz) in Bending
Get PDFThe effect of loading rate on the viscoelastic response of cassava roots, at a moisture content of 52.13 ± 5.74% (w.b.), to applied bending forces was studied. Experiments were conducted using a modified Instron Testing Machine (ITM) of 1 kN capacity, to investigate both creep and stress relaxation (viscoelastic) behaviour of cassava roots (variety TME 419) when static bending forces were applied at mid-span with loading rates of 2.7, 4.2, 5.3, 7.45, and 9.9 mm min-1. The creep behaviour indicated that the creep compliance may be described using a 4-element model consisting of Maxwell and Kelvin models in series. The retardation time and the instantaneous creep compliance of cassava root were found to be 25.5 s and 0.03009 (N mm-2)-1, respectively. The stress relaxation behaviour could be represented using a 2-element Maxwell approach with a parallel-orientated spring. The relaxation times are 20 and 500 s, for the range of the loading rates. Relaxation modulus was found to be a function of the degree of loading, rising as the degree of loading intensified and decreasing with time. As the loading rate increased from 2.7 – 9.9 mm min-1, the relaxation modulus increased from 1.25 – 6.89 N mm-2. The result of this study gives an idea of the food product attributes vis-à-vis its strength characteristics to mechanical damage. It guides the food process engineer in estimating the impact of stress on cassava roots during postharvest operations for optimum design of efficient cassava peeling machines and product storage quality. Prospects for further work were stated.
 
Sizing Analysis of Hybrid Energy Supply for Buildings Integrated with Battery Storage
Get PDFOne of the limitations in the application of renewable energy sources is the intermittency and variability in its supply. This characteristic has attracted many researchers and stake-holders to focus on the application of different types of hybrid energy technologies with storage systems to improve in the efficiency of the supply and dispatch ability of the system. The application of hybrid energy technology to generate heat and electricity is very popular nowadays and sustainable in the supply of energy for on-grid and off-grid services. The sizing of the hybrid energy supply is paramount to saving energy and meeting the energy demand at all time. This research work involves an analysis for sizing hybrid energy supply integrated with battery storage to meet the energy demand for 3-bedroom, office, sports and school building. Merit modelling tool was applied for the demand and supply matching and analysis of the various chunks of technologies of PV, WT, CHP and generator were carried out based on the suitability to achieve the best matching. The results show that hybrid systems with output capacities of 2.96 MWh, 203.15 MWh, 1.38 MWh and 2.14 MWh were used to meet the energy demands of 3-bedroom, office, sports and school buildings. The office building energy sizing was achieved with a match rate of about 90% with no energy deficit. However, surplus energy of 34.2MWh was recorded. The 3-bedroom, sports and school energy sizing were achieved with less than 1MWh of energy surplus or deficit and a matching rate of about 60%. For future study, the performance of the identified energy technologies can be verified using an integrated building performance simulation tool to ascertain its feasibility.
 
Some Physical Properties of Acha (Digitaria exilis) Relevant in Mechanical Dehulling and Cleaning
Get PDFThe properties of acha (Digitaris exilis) are important in the development off efective machines for dehulling and cleaning of the paddy. In this study, some of the relevant crop properties were determined, such as; moisture content, length, width, thickness, size and shape, arithmetic, geometric and equivalent mean diameters, surface area, volume and a thousand weight. Others includes; bulk and solid densities, porosity, angle of repose and coefficient of static friction. The fineness modulus, uniformity coefficient, particle size distribution and terminal velocity were determined for both paddy acha and grains. The properties were determined using standard methods at the moisture content of 10.3% (db) in replicates. The results showed that the length, width, thickness, size of grain, flatness index, thousand grain weight, angle of repose, angle of internal friction, bulk and solid densities were 1.58 mm, 0.90 mm, 0.76 mm, 1.58 mm, 1.65, 0.53g, 24.7o, 0.46o, 608.01 kg m-3 and 1131.0 kg m-3 respectively. The terminal velocity, porosity, coefficient of static friction, arithmetic and geometrical mean, equivalent diameters, surface area, volume, fineness modulus (paddy), fineness modulus (grain), particle size distribution (grain), particle size distribution (paddy), uniformity coefficient (grain), uniformity coefficient (paddy) was 3.96 m s-1, 46.24, 0.459, 1.127 mm, 1.859 mm, 1.059 mm, 3.36 mm², 3.00 mm3, 3.17, 3.00, 0.34, 0.36, 0.63 and 0.60 respectively. Thus, the acha (paddy and grains) can be classified as medium size and spherical in shape. In the sieve analysis of the paddy acha, 99.57 % of the paddy was retained on 0.351 mm mesh while 27.27 % and 61.72 % of the grains were retained on the 0.894 and 0.351 mm meshes. This is indicative of more variability in the grains than in the paddy. The properties show that the paddy separates easily and the grains are easily cleaned from contaminants
Optimization of Vitamin A in Red Guinea Corn-Millet Mix
Get PDFThis study focused on the optimization of vitamin A in guinea corn and millet mix. The concentration of vitamin A was investigated under the following conditions: blending time (1.5 - 5 hours), amount of red guinea corn (10 - 50g) and amount of agro residue (50-100 g) using Box-Behnken design. Statistically significant model (p<0.05) was developed to represent the relationship between the response (concentration of vitamin A) and the independent variables. The model showed a significant fit with experimental data with R2 values of 0.94. Analysis of variance (ANOVA) results showed that the concentration of vitamin A was influenced by the blending time, amount of red guinea corn and amount of millet used. Additionally, response surface methodology (RSM) was used to optimize the concentration of vitamin A. The results showed that maximum concentration of 98.76 µg/100g for vitamin A was obtained at the optimum production conditions of blending time of 5hours, 49.79g of red guinea corn and 100g of millet. The blend produced at the optimized conditions satisfied the World Health Organization (WHO), Food and Agricultural Organization (FAO) specification for recommended safe intake for all age groups, pregnant and nursing mothers
Chemical Composition Ananlysis of Coconut Shell Powder and Ash for Composite Reinforcement.
Get PDFThe use of natural resources which are environmentally friendly to replace the conventional composites materials had been the interest of many researchers lately. Beside the use of natural fibres as reinforcement in polymer matrix composites, the use of fillers made from natural sources such as coconut shell, corn cobs, palm kernel shell, rice husk, has been confirmed to be potential material that can offer some good properties to satisfy the requirements needed for some engineering applications. In this study, the potential of coconut shell powder and coconut shell ash were investigated. Fourier transform infra-red spectroscope was used to determine the chemical compositions of the samples. The results obtained revealed that coconut shell powder and coconut shell ash demonstrated comparable chemical properties to the conventional composites. The presence of some basic elements which are required to produce reinforcement materials with high strength, durability, light weight and corrosion resistance were confirmed. The results obtained revealed that coconut shell powder and coconut shell ash could be used as composites and other polymer matrix that are required for engineering application