ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY AND ENVIRONMENT <p align="justify">The Arid Zone Journal of Engineering, Technology and Environment is peer reviewed journal with the objectives to explore, develop and elucidate the knowledge of Engineering design and technology, to keep Practitioners and Researchers informed on current issues and best practices, as well as serving as a platform for the exchange of ideas, knowledge and expertise among technology researchers and practitioners. AZOJETE is published by the Faculty of Engineering, University of Maiduguri, Nigeria.</p> <p><strong>p-ISSN:</strong> 1596-2490 | <strong>e-ISSN:</strong> 2545-5818</p> <p><strong>PUBLICATIONS:</strong> MARCH, JUNE, SEPTEMBER AND DECEMBER</p> <p>AZOJETE is currently indexed in the following indexing platforms</p> <p><a href=";hl=en&amp;authuser=1" target="_blank" rel="noopener">GoogleScholar</a>, <a href="" target="_blank" rel="noopener">DOAJ</a>, <a href="" target="_blank" rel="noopener">ACADEMIA</a>, <a href="" target="_blank" rel="noopener">ResearchBib</a>, <a href="" target="_blank" rel="noopener">CosmosIF</a>, <a href="" target="_blank" rel="noopener">CiteFactor</a>, &nbsp;Bielefeld University Library, IIJIF, SIS, Cosmos Impact Factor, <a href=";subAction=subjects&amp;publisherID=34&amp;journalID=38287&amp;pageb=1&amp;userQueryID=&amp;sort=&amp;local_page=&amp;sorType=&amp;sorCol=" target="_blank" rel="noopener">JournalTOCs</a>, <a href="" target="_blank" rel="noopener">OAJI</a>,&nbsp; Journal Factor, SPARC Indexing, <a href="" target="_blank" rel="noopener">OpenAIRE</a>, Eurasian Scientific Journal Index, Electronic Journals Library, ISI, Social Science Research Centre Berlin, <a href="" target="_blank" rel="noopener">WorldCat</a>, International Institute of Organized Research (I2OR), StudyLIB,&nbsp; Journal Finder, <a href="" target="_blank" rel="noopener">University of Saskatchewan Library</a>,&nbsp; ScopeMed, Microsoft Academic, <a href=";recordsPage=2" target="_blank" rel="noopener">PKP Index</a>, <a href="" target="_blank" rel="noopener">efita</a>, JournalFinder, <a href="" target="_blank" rel="noopener">Publons</a>, <a href="" target="_blank" rel="noopener">Ghent University Library</a>, University Library of Regensburg, University of Groningen Library, University of Georgia, Berkeley Library University of California, ProQuest, <a href="" target="_blank" rel="noopener">ISSN Portal</a>, <a href="" target="_blank" rel="noopener">PIST</a>, <a href="" target="_blank" rel="noopener">DRJI</a>, <a href="" target="_blank" rel="noopener">TEEAL</a>, <a href="" target="_blank" rel="noopener">Technical University of Braunschweig</a>, <a href=";View=uba&amp;Language=de" target="_blank" rel="noopener">University Library Augsburg.</a> <a href="" target="_blank" rel="noopener">The Leipzig University Library,</a> <a href=";context=L&amp;vid=44HYG_INST:44HYG_VU1&amp;lang=en&amp;search_scope=MyInst_and_CI&amp;adaptor=Local%20Search%20Engine&amp;tab=Everything&amp;query=sub,exact,Agricultural%20Engineering%20,AND&amp;mode=advanced" target="_blank" rel="noopener">London School of Hygiene and Tropical Medicine</a>, <a href="" target="_blank" rel="noopener">EuroPub DASJ</a>, <a href="" target="_blank" rel="noopener">SJIF</a>, <a href="" target="_blank" rel="noopener">Technical University of Braunschweig</a>, <a href="" target="_blank" rel="noopener">EuroPub</a>, <a href=";R=3747465" target="_blank" rel="noopener">Toronto Public Library</a>, <a href="" target="_blank" rel="noopener">EDUINDEX Index of Education</a></p> en-US <p>Copyright of the paper named above is hereby assigned and transferred to the Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria.</p> (Prof. N.A. Aviara) (Engr. S.K. Oyeniyi) Tue, 01 Sep 2020 00:00:00 -0400 OJS 60 Mathematical Modeling of a Flat Plate Solar Collector with Eutectic Salts as Phase Change Material <p><em>Solar energy is the most promising heat source for meeting energy demand without having negative impact on the environment. Solar energy is, however, intermittent in nature and time dependent energy source. In order to mitigate the intermittent supply of solar energy for water heating, the use of phase change material&nbsp;(PCM) comes into play. The PCM acts as a heat source for the solar heating system when the intensity of the solar radiation is low or no longer active. &nbsp;Knowledge about the thermal effectiveness of solar collector with PCM is paramount.</em><em>&nbsp;</em><em>So, this study developed a mathematical model to evaluate the thermal behavior of a flat plate solar collector integrated with a phase change material (PCM). This mathematical model developed for the flat-plate with PCM was based upon the conservation and heat transfer equations and used to predict the thermal behavior of integrated phase change material in solar collector during thermal storage. The energy balance equations for the flat-plate heating components of the collector and PCM were formulated numerically. The model was used to investigate the effect of inlet water temperature, water mass flow rate, outlet water temperature and the melt fraction during charging and discharging modes at each of the respective nodes. A comparison was made with a collector with and without PCM. The results show that charging and discharging processes of PCM have multiple stages. &nbsp;The addition of PCM in the first stage causes a decrease in temperature during charging and an increase during discharging. The highest water temperatures reached for the collector without and with a phase change material were approximately 51 and 74°C respectively&nbsp;Comparisons were also made between the simulated and experimental data for the solar water heater without and with PCM. Minimum inlet water temperatures of 41.54 and 36</em><em>°</em><em>C were observed for the simulated and experimental model while, 42.69 and 74</em><em>°</em><em>C were both recorded for outlet temperatures respectively, for solar water heater without PCM. For the solar water heater with PCM, the inlet temperatures for the simulation and experimental model were found to be 42</em><em>°</em><em>C and 56</em><em>°</em><em>C respectively. A maximum outlet water temperature of 108</em><em>°</em><em>C was obtained from the experimental model compared to 45</em><em>°</em><em>C obtained from &nbsp;&nbsp;&nbsp;simulation. &nbsp;The temperature of the hot water obtained was remarkable and sufficiently enough for many domestic and industrial applications. Finally, the solar water heating system with phase change materials finds useful application and acts as a renewable energy resource in regions where there is &nbsp;&nbsp;inconsistent or poor sunlight.</em></p> O. F. Isamotu, N. A. Musa, O. J. Okegbile, M. A. Oriaifo, A. O. Bakare Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Development of a Laboratory Size Single Toggle Jaw Crusher for Artisanal Miners and Stone Workers <p><em>Comminution of minerals and stones in Nigeria is laden with myriads of resource challenges associated with other developing nations. A typical challenge is the need to import costly mining and mineral processing machineries or replace their components. To address this challenge, economic consideration was prominent in the development of components for the single toggle jaw crusher. Geometric modeling and structural/stress analysis of the components were achieved using Pro/Engineer</em><em><sup>®</sup></em><em>&nbsp;and Autodesk Inventor</em><em><sup>®</sup></em><em> computer applications. Designed eccentricity of 7 mm resulted in 5 mm throw and 0.01° angle of twist in the eccentric shaft. The designed base frame was statically stable, having yielded a maximum displacement of 0.008066 mm. Analysis of the compression spring indicated design compliance. Also, hardfaced crusher jaws and large diameter pulley and flywheel were developed. Selection of a three-phase, 3730 W electric motor resulted in a 0.24 ton/hr capacity jaw crusher in service. Optimal and maximum feed of the crusher were found to be 0.5 kg and 1 kg, respectively. Average eccentric shaft speed decreased with increased mass of granite lumps undergoing crushing. Therefore, the methods presented can be adopted in developing affordable and easily maintainable jaw crushers for artisanal miners and stone workers in Nigeria.</em></p> C. Okechukwu, O. A. Dahunsi, P. K. Oke, I. O. Oladele, M. Dauda Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Effects of Operational Conditions on Exergy Behaviour of Biomass Densification System and Durability of the Densified Biomass <p><em>Energy resources such as electricity and fuel are used to power biomass densification system for production of solid biofuel, however, energy consumption of the densification equipment has led to high cost of production of the solid biofuel. Meanwhile, energy stored in fuel or the electricity is being used to budget for the work or power requirements during densification of biomaterials which are mostly considered as energy consumption. The energy consumption does not give appropriate recognition to the exact or useful energy from the energy source that is energy output of the system. This study to investigates the effects of operational conditions of a biomass densification system on the exergy behaviour of a biomass densification system. The exergy parameters such as exergy input and exergy output were considered to determine the behaviour of biomass densification system. The conditioned biomass materials at 6%, 10% and 14% moisture contents (MC) were densified at selected applied pressures of 186.56, 211.38, 236.25, 261.17, 286.07 and 310.85 MPa, while each selected pressure was applied at different speeds of 10, 20, 30, 40, 50 mm/min. The exergy parameters obtained were subjected to statistical analysis using IBM SPSS 20.0 to determine the effects of the operational conditions on the exergy behaviour of biomass densification system. The highest mean values of exergy output of 0.3562 J and 0.4033 J were observed at 10 mm/min when pressure of 310.85 MPa was applied using sawdust and huskdust both at 6% MC, respectively to produce one-unit average weight of 12g of biofuel. The least mean values of exergy output of 0.1001 J and 0.1738 J were observed at 50 mm/min when pressure of 186.56 MPa was applied using sawdust and huskdust both at 14% MC respectively. Additionally, densified biomass of high durability was obtained when both sawdust and huskdust were densified at 10% Mc wet basis while the less durable densified biomass was obtained at 6% MC for sawdust and huskdust. Therefore, the operational conditions of biomass densification system such as applied pressure, speed of pressing piston and MC of biomass materials had effects on the exergy input and exergy output as well as the durability of the densified biomass.</em></p> <p><em>It was then concluded from this study that the operational conditions of biomass densification system can affect the exergy behavior of the system and the quality of densified biomass.</em></p> J. O. Olaoye, F. B. Olotu, O. A. Lasode, I. P. Duniya Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Potentials of Utilizing Biodiesel from Cotton Seed Oil Blend with Diesel as an Alternative to Diesel Fuel in Nigeria <p><em>The depletion of fossil fuel reserves coupled with the environmental challenges pose by fossil fuel utilization make it necessary to search for better alternative fuels that have less adverse impact to the environment. Biodiesel and its blends as an alternative fuel in compression ignition (CI) engines are receiving more attention from researchers. This study investigates a blend of biodiesels from cottonseed oil and pure diesel prepared in percentage by volume in a proportion of 0:100, 10:90, 20:80 and 30:70 respectively. They were labeled as B0, B10, B20, and B30, and run on a single-cylinder, four stroke and water-cooled 165F diesel engine. The results show higher brake power for all blends when compared with pure diesel, with the lowest difference of 0.43% for B10 at a torque of 10 Nm and highest of 2.06% for B30 at 2 Nm torque. Specific fuel consumption (SFC) was also higher for the blends as compared to pure diesel, but the SFC is compensated with higher brake power. Pure diesel is observed to be thermally more efficient than biodiesel blends at low torque. The thermal efficiency difference ranges between 6.6–13.3% at 2 Nm. But at the torque of 10 Nm, the thermal efficiency of all blends is higher than pure diesel with about 3.3%. B30 shows better engine performance than pure diesel and the other two blends, but with slightly higher fuel consumption.</em></p> I. A. Hussain, I. U. Ibrahim, B. A. Ishak, A. S. Ahmed Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Modelling of Heat Transfer Through Hollow Blocks Produced with Rice-Husk-Ash Blended Cement. <p><em>Hollow sandcrete blocks are widely used in many countries of the world. In recent years, cement content is being partially substituted by admixtures especially agricultural wastes. Modeling of heat transfer characteristics of these modified blocks is essential in order to predict their thermal performance. This study focuses on this modeling with the aid of a finite-volume based computer code. Specifically, for regular, two-cavity blocks produced with the cement partially substituted with rice husk ash (RHA). The result showed that as the percentage substitution of RHA increased, thermal gradient across the width of the block increased, while the rate of heat flow reduced. The second part of the study examined the effect of heat transfer through the air-gap as compared to a similar study regarding it as vacuum. The heat flow through the air-gaps of the building bricks affected the pattern of heat flow within the bricks, hence, they could not be regarded as a vacuum. The results of this study will be useful to building professionals in the choice of building blocks and proper estimation of air- conditioning load in buildings.</em></p> O. M. Kamiyo Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Modification and Performance Evaluation of a Fish Feed Pelletizing Machine <p><em>A hand operated fish feed pelletizing machine for the production of fish feed with through put capacity of 2.56 kg/h was modified, fabricated and evaluated due to non-availability of electricity in the rural area, drudgery and low throughput capacity. It consists of a hopper, barrel that houses the screw conveyor (auger), the cutting knife, and the die orifice. Power supply to the machine is a 6-kw petrol engine. It was observed that the pelletizing efficiency and throughput capacity increase with proportionality of smallness of die diameter. The modified machine test results showed highest throughput capacity of 162.8 kg/h with maximum pelletizing efficiency of 85.3%. The total production capacity of the machine was 150 tons per day, which is adequately to feed up to 3,000 fish per day. The adoption of the pelletizing machine by farmers will enable them produce their own feed from local plant and animal waste source thereby alleviating the problems associated with the sourcing of imported feeds.</em></p> G. S. Malgwi, S. A. Abdulkadir, S. M. Dodo Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Design and Construction of an Agricultural Waste-Shredding Machine <p><em>Waste generation has become a major concern to the government, environmental regulatory bodies, and the society, especially with the current population pressure as well as the economic and social factors in Nigeria. This study was focused on design, construction, and performance evaluation of an Agricultural Waste-Shredder using locally available materials. The selected materials used to fabricate the machine were Metal sheet, Angle iron bars, Pulleys, belt, shaft, and Prime mover. The shredder has the feeding unit, the shredding unit, power transmission unit and the machine frame. The performance of the machine evaluated with beans stalk, the performance indices investigated were shredding efficiency and throughput capacity. Response surface methodology (RSM) was used to Maximize the efficiency of the machine at operational Speeds of 360rpm, 650rpm, and 975rpm with sieve apertures of 20mm, 30mm, and 40mm respectively. Maximum shredding efficiency of 93% was obtained when the shred aperture was 20mm at shredding speed of 975rpm. The maximum throughput capacity was 6.10kg kg/m at speed 975rpm and a minimum value of 5.14kg/m at 325rpm respectively. A quadratic model for shredding efficiency explained 94.78% of the variation in shredding efficiency. R</em><em><sup>2</sup></em><em>&nbsp;(pred) of 70.42% suggests that the model is fit. The machine is easy to use and with a low cost of production to small and medium scale entrepreneurs in agriculture.</em></p> S. A. Abdulkadir, S. M. Dodo, B.G. Jahun, G. S. Malgwi, I. Vanke Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Productivity and Allocative Efficiency of Quail (Cortunix Coturnix Japonica) Production using Different Rearing Techniques in Nigeria. <p><em>Small scale poultry production plays a major role in bridging the protein deficit and sustain rural livelihood in Nigeria. This study assesses the productivity and allocative efficiency (AE) of quail (Cortunix coturnix japonica) production using different rearing techniques in Nigeria. In this study, both primary and secondary data were collected from 193 quail poultry farmers comprising of 78 battery cage system (BCS) and 115 deep litter system (DLS) operators using a multi-stage random sampling procedure. Descriptive statistics, profitability indices and stochastic frontier function were used to analyse the data. The stochastic frontier cost function was used to estimate the factors influencing AE of farmers in quail production. The results show a gross margin of N1, 455.51, net poultry returns of N1157.47 per quail bird for BCS thrives better compared to N800.00 and N751.96 estimated in DLS respectively. The estimated profit margin (26.81 %) and return on investment (1.37) in BCS were also higher than 26.54 % and 1.36 respectively in DLS. The ROI result indicates that a N1.00 investment in BCS and DLS yields N0.37 and N0.36 respectively. AE results revealed that the coefficient of costs of feed (0.287), hired labour (-0281), family labour (0.309) and depreciation of fixed items (-005) were found to be statistically significant variables in BCS quail production. Conversely, costs of feed (0.109), cost of hired labour (-0.007) and family labour (0.188) statistically influence DLS quail production. The inefficiency sources model for BCS showed that age, formal education, access to credit and investment are the significant factors. Furthermore, formal education, access to production credit and level of investment contributed significantly to the explanation of efficiency in DLS production unit. Therefore, it is suggested that quail farmers should strive to optimize efficient use of inputs to increase output and profit. This will be an impetus to achieving sustainable poultry production in the studied areas.</em></p> Y. U. Oladimeji, H. O. Yusuf, H. A. Yusuf, H. Shuaibu, T. O. Olarewaju Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Design and Implementation of Solar Street Light for Scarcely Electrified Areas <p><em>Streetlights are usually powered by alternating current supply from distribution stations of &nbsp;the utility companies. This invariably increases the demand for power distribution from utility companies. Recent developments, however, suggest the possibility of the use of renewable energy sources to power streetlights in order to reduce the demand on the consumption rate of energy on the utility companies. Accordingly, this work considered the design and implementation of streetslights in scarcely electrified areas powered by solar energy. Using tilted solar modules, energy efficient lamps, and structural anticorrosion parts, a standalone streetlight configuration with automatic switch ON/OFF mechanism was built. The results show that streetlight powered by solar source of renewable energy cheaply generates electricity directly from sunlight without emissions, noise, or vibration. Therefore, due to the inconsistencies surrounding the generation of electricity using fossil fuels, this work offers an alternative source to power streetlights thereby reducing pressure on the national grid</em><em>.</em></p> A. A. Okandeji, Z.O. Jagun, M. B. Olajide, F. Onaifo Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Enhancing Oil Recovery through Waterflooding <p><em>Waterflooding is a simple and cheaper means of improving oil recovery from a reservoir by injecting water into the reservoir. Economic considerations suggest injection and production wells must be optimally placed considering reservoir geology, fluid properties, and well orientation. This study focuses on the effects of well placement and orientation on the performance of waterflooding process. The reservoir has a dimension of 2500 ft by 2500 ft by 150 ft. It is homogenous in porosity and heterogeneous in permeability. The performances of three cases considered in the study were evaluated and compared. Water production rates, bottom hole pressure limits for producer wells, well water cut and net present value (NPV) over the entire production period were considered in evaluating their performances. Reservoir modeling and simulation were carried out using MATLAB Reservoir Simulation Toolbox (MRST). It was verified from the investigation that Case III has a maximal production rate of 1,110,188.6 stb/day (stock tank barrel per day), decreasing to 11,005 stb/day after a span of 1400 days with a pressure decrease. Consequently, it was considered a better choice in terms of well placement. It was also estimated to have a maximal Net Present Value of 19.8 billion dollars, which makes it economically viable.</em></p> A. S. Grema, M. K. Mahlon, A. S. Kolo, U. H. Taura Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Comparative Study of Durability and Microstructure Properties of Concrete made with Different Grades of Nigerian Portland Limestone Cement <p><em>It is now becoming apparent that concrete should not only be strong but must also be durable. It is also believed that understanding the microstructure of the concrete will help produce strong and durable concrete, and thus enhance innovativeness in concrete application. This paper compares the durability performance and microstructure development of concrete produced with Portland limestone cement (PLC) grades 32.5R and 42.5R. The durability investigation was accomplished through coefficient of water absorption and sorptivity measurements. The scanning electron microscopy (SEM) was used to investigate the microstructure of the concrete samples. &nbsp;The results show that concrete produced with cement grade 42.5R showed higher durability potential than the ones produced with grade 32.5R using 28 days curing period. Similarly, it was also observed that concrete specimens produced with 32.5R and with water/cement ratio of 0.40 have better durability index at the later dayscuring of 90 days in comparison to grade 42.5R concrete specimens. &nbsp;It can be concluded that concrete produced using grade 42.5R cement has potential for better durability performance in relation to concrete produced with 32.5R</em></p> C. A. Fapohunda, B. I. Famodimu, B. C. Adigo, A. S. Jeje Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Design, Construction and Performance Evaluation of a Manually Operated Meat Mincing Machine <table> <tbody> <tr> <td width="74.1800%"> <p><em>In this study, a manually operated meat mincing machine was designed, constructed and its performance evaluated. The machine consists of; a single start worm auger called the shaft, a four-blade crosshead knife, a perforated plate, handle, mincing cover and a mincing head which comprised a hopper and an anchor bracket. All components of the machine were fabricated from locally available materials (stainless and mild steel) and based on the determined design parameters. The auger, mincing head, the crosshead knife and perforated plate were constructed from stainless steel material. Mild steel was used for the construction of the anchor bracket, mincing head cover and handle of the machine. These components were fabricated using the process of measurement, marking, cutting and joining. Vernier caliper and steel rule were used for measurement, scriber used for marking, center lathe machine, drilling machine, hark saw, hand snip and hand files were used for cutting. While arc welding and bolting were used the joining process. The auger had a shaft diameter of 0.025 m, worm diameter of 0.05 m and a total length of 0.22 m. The mincing head had an internal diameter of 0.052 m and external diameter of 0.06 m. The result shows that the machine can mince </em><em>&nbsp;fresh meat in </em><em>&nbsp;seconds, </em><em>&nbsp;of perboiled meat in </em><em>&nbsp;seconds and </em><em>&nbsp;of overcooked meat in </em><em>&nbsp;seconds. The critical load of the auger which is the major component of the machine is </em><em>&nbsp;with a maximum stress of </em><em>&nbsp;The efficiency of the machine was 50% at a velocity ratio of 0.88 and mechanical advantage of 1.8 with a total production cost of seven thousand three hundred and ninety two naira (₦7,392). The machine will serve as a means of providing minced meat to children, elderly and the sick especially in rural areas that have no access to electricity.</em></p> </td> </tr> </tbody> </table> F. M. Kajiama, M. A. Aji, M. Shuwa, E. B. Taktak Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 An Overview of Approaches and Techniques used in Failure Analysis of Engineering System <p><em>Failure of engineering system such as vehicle, building, aircraft, bridge, equipment, and industrial facility is often inevitable with calamitous consequence and/or much loss; and is highly detested. Inevitability of engineering system or component failure stems from factors such as unavoidable corrosion and wear and tear, abnormal service conditions, substandard maintenance practices, improper inspections, production errors, design errors, injudicious selection of materials, material imperfections, overloading and other service abuses of the system or component; and unknown causes. The importance and value of failure analysis in providing vital information for preventing recurrence of failure case of engineering system and the need to properly conduct the analysis has been found well documented in the literatures. Various standard approaches and techniques of engineering system failure analysis have been reviewed and presented together with 24 recent works of researchers from different backgrounds on the subject who have taken particular cases for study and evaluation. The review shows that although there are many existing failure analysis approaches and techniques of engineering systems, not all or a number of them can be suitable for every particular failure case. Critical analysis of the approaches and techniques shows that each has limitations or demerits in terms of practicability and/or cost-justification for particular failure cases. The notable issue in the review is the need to always select &nbsp;the best approaches and techniques for particular failure cases &nbsp;to assess characteristics that are present in the failed/damaged engineering system or item and those that are supposed to be present in it before failure, the differences between the damaged and undamaged system or item, and results of tests that must be performed to substantiate explanations and refine knowledge about the observed damage to correctly reveal the root cause/s of failure. Another important thing found from the review is the need to first and foremost preserve evidence of the failed system or item before using the best approaches and techniques to get as much as possible information from the field failure conditions and background realities and laboratory tests of the failed system or item. The review is posited as a readily available compendium of basic practicable information that is easy to read and understand; for consultation by concerned students, researchers, and practitioners who are not yet much experienced in failure analysis of engineering systems and need the information for furthering their knowledge on the subject.</em></p> T. N. Guma, N. C. W. Ozoekwe, K. V. Odita Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Investigation of Chemical Composition of a Steam Turbine Shaft (A Case of Kaduna Refinery) <p><em>An investigation of the chemical properties of Original Equipment Manufacturer’s (OEM) steam turbine shaft and that of locally produced shaft was carried out to determine the chemical composition of the shafts and determine the suitability of the locally produced shaft to replace the OEM turbine shaft that is in constant failure. The chemical analysis carried out on the samples revealed that the OEM turbine shaft is composed of 0.48C, 0.06S, 0.12Ca, 0.99Cr, 0.36Si, 0.71Mn, 0.07P, 0.12Ni, 0.15Cu and 0.39Mo and the locally manufactured steam turbine shaft is composed of 0.38C, 0.07S, 0.038Ca, 0.89Cr, 0.83Si, 0.63Mn, 0.04P, 0.04Ni, 0.16Cu and 0.20Mo. Manganese which was found to increase hardenability and tensile strength is lower in the locally manufactured shaft as compared to the OEM steam turbine shaft. The analysis also showed that carbon, Sulphur, chromium, phosphorus, Nickel and Molybdenum content of the original steam turbine shaft is higher than that of the locally manufactured shaft. The results obtained agree with the ASTM A668 steam turbine shaft requirement under class D standard of the chemical composition.</em></p> D. K. Garba, M. J. Muhammad, U. S. Umar, N. C. A. Ozoekwe Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Performance Evaluation of a Melon Seeds Shelling and Separation Machine <p><em>The scarcity of information on the performance of most machines developed in Nigeria impedes the commercialization of proven indigenous technologies. A newly developed melon seeds shelling and separation machine with the capability to continuously shell conditioned melon seeds and simultaneously separate the seed cotyledons from it shells was evaluated. The machine extracts heat exclusively from the exhaust gases of a gasoline prime mover by heat conduction principle, mildly dry the shelled melon seed mixture before effecting separation of the cotyledons from it shells by aerodynamic and screening principles. &nbsp;Based on preliminary studies, performance evaluation of the machine was carried out at 900, 1500 and 2100 rpm operating speed and 14, 20 and 26% db moisture content of white edge (Serewe) melon seed variety. The data obtained were analyzed using IBM SPSS statistic software version 25. Results of Analysis of Variance (ANOVA) at P ≤ 0.05 showed that, shelling efficiency and machine capacity varies significantly with the operating speed, moisture content of the seeds, and their interactions; while separation efficiency and seed breakage percentage varies significantly with the operating speed and moisture content of the seeds but not significant with their interactions. An optimal performance of 96% shelling efficiency, 95% separation efficiency, 2.67% seed breakage percentage and 54.23 kg/h machine capacity, was obtained at 2100 rpm operating speed and 20% db seed moisture level. The performance of the machine is satisfactory and therefore recommended for commercialization and adoption by melon seed processors.</em></p> T. Iorpev, I. C. Ozumba, R. O. Onah, O. A. Adejumo Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400 Design Analysis of a Microcontroller Based Automatic Switching System using Passive Infrared Sensor <p><em>Poor management and conservation of public power supply has constantly resulted into wastage of electricity thereby limiting the industrialization process especially in third world countries. To reduce energy wastage in homes, institutions and public places, this paper presents the development of an automatic switch using passive infrared sensor (PIR). Automatic switch is a device that detects the human presence in a predefined area and can turn on the lights or any electrical appliances. Similarly, the device will automatically turn off the lights or any electrical appliance if nobody is present in the area. Using the PIR sensor (for human detection), Light Dependent Resistor (LDR) (to detect night and day), and a microcontroller programmed using Micro-C, a switching circuit that detects humans in a predefined area is investigated. In particular, an automatic switching system using passive infrared sensors to prevent unwarranted wastage of electricity, and also to prevent electricity related hazards which could result from the use of unmonitored electrical appliances is implemented. The research work guarantees less consumption of power, hence, lower utility bills. Also, it allows for more safety in homes, schools, and offices since heavy-duty and high-power equipment that could cause fire e.g. Air-conditioning systems, electric cookers, boilers, electric irons etc, if left unattended to, can be turned off automatically.</em></p> A. A. Okandeji, Z.O. Jagun, M. B. Olajide, M. T. Kabir Copyright (c) 2020 Arid Zone Journal of Engineering, Technology and Environment published by University of Maiduguri, Nigeria. Tue, 01 Sep 2020 00:00:00 -0400