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Mann Library, Cornell University</a>,&nbsp;<a href="https://www.teeal.org/node/1477" target="_blank" rel="noopener">TEEAL</a></p> <div style="width: 400px;">&nbsp;</div> Faculty of Engineering, University of Maiduguri, P.M.B. 1069, Maiduguri, Nigeria. en-US Arid Zone Journal of Engineering, Technology and Environment 1596-2490 DEVELOPMENT OF A MODEL FOR MITIGATING FIRE SPREAD IN MULTI-STOREY BUILDINGS http://azojete.com.ng/index.php/azojete/article/view/596 <p>In the developing nations that are located in the tropical region; there is a growing trend of fire incidence in buildings without adequate development of fire prevention and/or reduction protocol. Thus, this study addresses the growth and spread of fire in multi-storey buildings. The rooms are structured as cells in order to reduce the flame spread from a single fuel item, by heat release, to other neighbouring items or rooms (otherwise known as cells). The philosophy is to reduce the advent of vertical and horizontal fire spread. Thus, the mathematical model for the spread of fire in buildings over a solid fuel surface is therefore developed using the adaptation, development and simulation of cellular automata (CA) discrete model. The von Neumann neighbourhood cell configuration is adopted. Hence, the surface of the fuel is analysed using a regular square array (i.e. cells), while the flame spread is depicted as a series of ignitions of surface elements. In which case, ignition of an element is evaluated by a combination of critical surface ignition temperature and cellular automata discrete techniques. The work displays the movement of fire, from its origin of ignition to other fuel igniting elements around it. Consequently, this spread to other parts of the building. However, the technique presented in this work attempts to reduce the rate of growth of the fire spread using the predictive fire growth probability approach. In other words, the application of the cellular automata, using a multi-storey building, is herein presented. The study has potential to advance knowledge of technical approach to stop fire spread in multi-storey building. Thus it improves fire risk management as well as reducing magnitude of fire disaster and losses in the multi-storey buildings.</p> P. O. Oluseyi T. O. Akinbulire C. T. Atunbi M. I. Akinyemi Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 190 206 DESIGN, CONSTRUCTION AND PERFORMANCE EVALUATION OF A SMALL SCALE BIOFUEL DISTILLER http://azojete.com.ng/index.php/azojete/article/view/597 <p>A biofuel distiller of 20 L feed capacity was designed fabricated and used to distill bioethanol from a biomass broth. The distiller consists of a 40 L volume boiler unit integrated to the combustion chamber as a cylindrical column; and a counter current cylindrical condenser of length, tube and shell internal diameter of 88 cm, 0.0191/0.15 m, inclined at 450. &nbsp;The reactor is a Top Lit Updraft (T-LUD) type fired with charcoal of moderate lump. Its performance evaluation was conducted using 20 L palm bunch broth as the distiller feed. The palm bunch collected from Siat Nigeria Ltd, Ubima, Rivers State, Nigeria, was physically pretreated by grinding to powder, hydrolyzed with 1.2 % dilute H<sub>2</sub>SO<sub>4</sub>, at 160°C for 30 min and fermented for 72 h with S.cerevisiae separated from palm wine. The broth was then separated from the slurry by filtering before distillation. The result of the machine evaluation showed that 817 ml bioethanol was obtained per batch at 20 min from the bubble point which took 95 min. Actual combustion efficiency was found to be 55 % with reactor power rating of 12.2 kW. The machine vaporized bioethanol fuel from the boiler feed fed at 27°C, and released the distillate at 28.3°C. Distillation efficiency was found to be greater than 90 % while the maximum productivity occurred at 10 min from the bubble point. The machine is economical, reliable, convenient to use and can stand diverse environmental conditions. It can be integrated as a waste management step in the downstream end of palm mill operations.</p> L. N. Onuoha M. O. I. Nwafor J. O. Igbokwe N. A. Aviara Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 207 225 ASSESSMENT OF INFORMATION TECHNOLOGY ADOPTION IN PROJECT INFORMATION EXCHANGE IN NIGERIAN CONSTRUCTION INDUSTRY http://azojete.com.ng/index.php/azojete/article/view/598 <p>Information Technology (IT) has been applied by various industries with significant improvement in the practice and strategic standing of the industries. Its successful application is evident in manufacturing, petroleum, banking, aerospace and military industries. However, despite this evidential benefit as a result of IT adoption, delayed receipt of project information and/or loss of the project data/information are still prevalent in the Nigerian construction industry. To reduce these inefficiencies in the data management of the industry, this study investigates the medium of project information exchange and examine the order of IT adoption in the Nigerian Construction industry. A quantitative approach using questionnaire survey was employed. Structured questionnaires were distributed among quantity surveyors in contracting, consulting and public sector. The resultant data was analyzed using descriptive statistical tool. The results revealed the dominance of the paper-based medium over the use of IT tools in information acquisition and dissemination in the construction industry. About three-quarter of drawings, specifications and schedules were acquired through printed copy (paper based), and only about one-tenth of these information were acquired through email and disk/flash. While about four-fifth of the bills of quantities, claims and final account documents/information were being disseminated through the traditional paper-based printed copy, and less than one-tenth of these information are being disseminated through email and disk/flash. The order of IT adoption and use in information acquisition in the Nigerian Construction industry was found to be paper based medium, then followed by online medium, email and others (mobile) came third and fourth respectively, while disk/flash and came fifth and sixth in ranking. Furthermore, in contrast to the order of IT adoption and use in information acquisition in the Nigerian Construction industry, paper-based and disk/flash medium came first and second in order of information dissemination. Emails and online medium came 3rd and 4th in place, while fax and others (such as mobile phone), came 5th and 6th in adoption and use. Thus, for construction professionals in developing countries to reap the benefit of IT, it must go beyond the use of paper based medium to the use of IT tools for the acquisition and dissemination of information in the industry.</p> Y. U. Datti A. Dahiru O. Olamilokun Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 226 236 EFFECT OF MOISTURE CONTENT AND GRAIN VARIETY ON FRICTIONAL PROPERTIES AND SPECIFIC HEAT CAPACITY OF ACHA (Fonio) GRAINS http://azojete.com.ng/index.php/azojete/article/view/601 <p>&nbsp;</p> <p>There are many varieties of acha, but the most prominent two are white acha (Digitaria exilis) and brown acha (Digitaria iburua). This study was undertaken to determine the static coefficient of friction, kinetic coefficient of friction and specific heat of the grains as influenced by moisture content. The moisture levels considered were 5, 11, 23 and 28% db for the white variety and 5, 9, 21 and 30% db. The study revealed that increase in moisture content resulted to increase in the value of the properties considered for both varieties, with the white acha showing the highest values. Static coefficient of friction increased linearly with moisture content and had maximum values of 0.49 - 0.62 for the brown variety and 0.52-0.66 for the white variety all on steel sheet, while the minimum values for both varieties were on glass surface. Kinetic coefficient of friction increased linearly with moisture content and the highest value was obtained on hessian bag material (0.62-0.66) with the least being on steel sheet (0.58-0.64) for the two acha grain varieties. The study further revealed that, specific heat capacity of acha grains increased with increase in moisture content from 2.93 – 11.29 kJ/kgK (5 – 28% db) for the white variety and from 2.33 – 13.88 kJ/kgK (5 – 30% db) for brown variety. This study concludes that variety and changes in moisture content significantly affected the determined properties of acha.</p> U. A. Kawuyo N. A. Aviara D. C. Okolo Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 237 247 ALOE VERA MUCILAGE AS DRAG REDUCING AGENT IN OIL-WATER FLOW http://azojete.com.ng/index.php/azojete/article/view/602 <p>Drag reduction is the deliberate reduction of the frictional pressure drop in flow systems by the addition of heavy molecular weight polymeric materials as well as other means such as pipeline modifications. Environmentally friendly and cheaper heavy molecular weight polymeric drag reducing agents (DRAs) has become a necessity in the transportation of fluids particularly in the oil and gas industry. However, very few reports exist on the potentials of natural polymers such as extracts from the Aloe Vera plant. In this study, the effects of Reynolds number and polymer concentration on the drag reduction effectiveness of Aloe barbadensis miller were tested. An experimental flow facility using unplasticized &nbsp;Polyvinylchloride (uPVC) pipe of 12 mm ID was constructed with diesel (density = 832 kg/m<sup>3</sup>, dynamic viscosity = 1.664 mPa.s at 25°C) and water (density = 1000 kg/m<sup>3</sup>, dynamic viscosity = 0.891 mPa.s at 25°C) as test fluids. Drag reduction as a function of Aloe polymer concentration in the range 50 ppm to 500 ppm and Reynolds number 20000&lt;Re&lt;90000 were investigated by comparing the U-tube manometer pressure drop readings with and without aloe polymer. The pressure drop difference expressed as a percentage of the pressure drop without aloe polymer is termed drag reduction and was used to demonstrate the effectiveness of the Aloe Vera extracts or polymer as a DRA. In single phase horizontal (water) flow, a maximum drag reduction of 64% (U = 4.67 m/s) was measured, while in multiphase horizontal flow, a maximum drag reduction of 53.80% (α = 25%, Um = 4.67 m/s) was measured. Furthermore, measurements showed that pipe inclination had minimal effect on the drag reduction achieved. It was deduced that Aloe Vera mucilage can be used as a drag reducing agent in oil-water flows for Reynolds number below 63,000.</p> M. N. Abdallah L. C. Edomwonyi-Otu A. Yusuf A. Baba Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 248 258 DESIGN AND IMPLEMENTATION OF AN ARDUINO BASED LIGHT DEPENDENT ALARM SYSTEM http://azojete.com.ng/index.php/azojete/article/view/603 <p>This paper is based on design and implementation of an Arduino based alarm system which is capable of monitoring the illumination of the surrounding automatically. Once the presence or absence of light is detected accordingly, a control device is activated which sends a sound alarm to a buzzer connected to the output of the system. &nbsp;Waking up early from sleep has always become a challenge most especially after a very hectic and busy engagement during the previous day time, this makes waking up early the next morning to meet up with the activities of the day a challenge. The components used for carrying out this study include Light Dependent Resistor, a control unit and an output buzzer unit. The LDR works on the principle of change of resistance based on the amount of luminous energy in its environment at that moment of time, once an illumination is detected, an Arduino Uno board was used to send a signal to the buzzer that generates sound when the intensity of light increases. The test conducted showed that the LDR resistance decreased as illuminance on the LDR increased; the illuminance ranges at which the buzzer was triggered was between 100-1000lux.</p> H. Ibrahim A. A. Mohammed I. A. Aliyu Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 259 267 OHMIC HEATING AS ALTERNATIVE PRESERVATION TECHNIQUE - A REVIEW http://azojete.com.ng/index.php/azojete/article/view/605 <p>The quest for new technologies in heating has drawn the attention of researchers to focus on energy saving and efficient techniques in heating food materials. Ohmic heating is one of these technologies because it heats both phases of food (liquid and solid) simultaneously by internal energy generated from electrical power. Using this method, the product undergoes minimum structural damage, retains its nutritional value, and is processed within a shorter time than with conventional heating methods. The technique also gives excellent processed quality products with lower energy cost. The heat energy generated during ohmic heating is transferred directly into the foods. The electrical conductivity of food products is linear with different temperature ranges and varies with heating time, food structure, and its constituents. As such, ohmic heating can be applied in different pre-processing and processing operations like drying, evaporation, dehydration, blanching, fermentation, extraction, sterilization, and pasteurization. This paper highlights ohmic heating as an emerging alternative novel heating technology to meet the demand for industrial and domestic food processing. Recommendations were made for further research to provide a more robust analysis of ohmic heating performance.</p> A. I. Muhammad A. Shitu M. A. Tadda Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 268 277 COMBUSTION MODELING OF A FIXED BED DOWNDRAFT BIOMASS GASIFIER USING COMPUTATIONAL FLUID DYNAMICS DESIGN http://azojete.com.ng/index.php/azojete/article/view/606 <p>Thermochemical conversion of biomass in a gasifier for the production of syngas provides the enabling technology for efficient biomass resource utilization. Gasification is a complex process involving the interactions of numerous parameters, hence CFD tool is usually utilized to numerically optimize the design and operation of the gasifier reactor for improved performance. The gasification of multiple biomass usually requires a complex set of facilities for experimental set up in order to determine the optimum operating conditions for maximum gas yield. When this is not available, it can pose a bottle-neck to process development and optimization. &nbsp;In this study, the GAMBIT and FLUENT were used to model and simulate the gasifier reactor with emphasis on the combustion and gasification (reduction) zones in order to maximize the thermal output of the combustor by an optimization of biomass fuel types. Model validation was achieved by showing a close agreement between numerical and experimental results within the same configuration, particularly to show the effect of temperature on the gasification of Fixed Bed Downdraft gasifier. The fraction of initial moisture content, air flow rate, temperature of the pyrolysis zone, and chemical composition of the biomass were the required input data for the model to predict the gasification temperature. Computations were carried out for rice husk, saw dust and corn cobs as gasifier fuels, whereby air was used as the oxidizing agent. The porosity and oxidizer velocity were varied between 0.1 – 0.5 and 5 – 15 m/s respectively. The predicted results compared with experimental data showed good agreement. The simulated temperature gradient also indicated that rich fuel combustion zone was greater for rice husk - corn cobs, an indication that improved gasification and pyrolysis were present.</p> S. A. Abdulrahman A. T. Abdulrahim A. M. El-Jummah Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 278 291 PATTERN OF RESIDENTIAL WATER DEMAND ANALYSIS FOR MAIDUGURI METROPOLIS, NORTH-EASTERN NIGERIA http://azojete.com.ng/index.php/azojete/article/view/607 <p>This study investigated the projected 50-year water demand of Maiduguri township from 2006 to 2056. The impact of socio-economic factors on water consumption pattern of the population was also assessed. Data were collected from 200 households using structured questionnaires and analyzed using Statistical Package for the Social Science (SPSS). The results show that on an average, a household in Jere and Maiduguri consumes an estimated 421.85l L/day while areas worst hit are new layouts and those covered by the phase 2 water treatment plant (yet to be completed). In addition, it was found that, gender, education, household size and income were statistically significant predictors of water demand. Furthermore, the results revealed that in 2006, the combined population of Jere and Maiduguri was 749,123, which was later projected to be around 3,618,579 by the year 2056. Similarly, water demand was estimated to rise to approximately 154,443 M<sup>3</sup>/day by the year 2056 to meet the water demand of the growing population. However, in 2006, the combined water supplied from Maiduguri water treatment plant and all the functional boreholes (public boreholes) stands at 31,973M<sup>3</sup>/day while in 2016 it rose to 43,811 M<sup>3</sup>/day. The increase was due to additional supplies obtained from boreholes provided by some Non-Governmental Organization (NGOs) in some locations across the two areas. It is noteworthy that water supplied in the year 2016 to the population was grossly inadequate to meet the household water demand. Therefore, with the projected water demand of about 154,443 M<sup>3</sup>/day by 2056, it is recommended that all existing water supply schemes including the proposed phase 2 of the Maiduguri surface water treatment plant designed to cover West end, Wulari, Bulunkutu and Maduganari areas to be completed to increase the supply. Service boreholes in newly established layouts should be put to operate at full capacity including the additional ones drilled. Also, the Dala Alamdari mini water works constructed by International Committee of the Red Cross (ICRC) which is operated below its installed capacity due to poor management to be enhanced.</p> A. Abdullah B. S. U. Ibn Abubakar A. N. Jones Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 292 303 EFFECTS OF PID CONTROLLER ON PERFORMANCE OF DISH ANTENNA POSITION CONTROL FOR DISTRIBUTED MOBILE TELEMEDICINE NODES http://azojete.com.ng/index.php/azojete/article/view/608 <p>Introduction of telemedicine into developing nation’s healthcare delivery scheme could be a solution to a number of challenges facing the scheme including acute shortage of medical personnel. Because of distribution and mobility nature of the system combined with Nigeria’s large land mass, the resulting propagation delay will be large which may lead to system poor quality of performance or instability if the system is not compensated. This study aimed at assessing the effects of introducing Proportional-Integral-Derivative (PID) controller into the control of the position of dish antenna mounted on distributed mobile telemedicine nodes within Nigeria when the link is via Nigcomsat-1R. The system closed loop composite transfer function was obtained and subjected to unit step forcing function which then yielded time domain parameters. There was reduction in the value of system time domain parameters obtained for PID controller compensated system compared to uncompensated system. Based on the value of the system time domain parameters obtained from the simulation, introduction of PID controller into this system has improved the system response significantly.</p> Copyright (c) 2019-06-01 2019-06-01 15 2 304 313 ENHANCED IMPINGEMENT JET COOLING OF GAS TURBINE WALL HEAT TRANSFER USING CFD CHT CODE: INFLUENCE OF WALL THERMAL GRADIENT WITH FIN AND DIMPLE OBSTACLES http://azojete.com.ng/index.php/azojete/article/view/609 <p>Gas turbine (GT) jet cooling using the regenerative or impingement jet backside cooling system is applicable to low NO<sub>x</sub>&nbsp;GT combustors and was investigated in the present work. The impingement heat transfer investigated is for the techniques where all the combustion air is used for wall cooling prior to passing through the flame stabiliser. Ten rows of impingement holes were modelled and are for four different types of obstacles: rectangular-pin in co- and cross-flows, circular pin-fin in cross-flow and dimple in direct-flow configurations, arranged in the impingement jet air flow direction. Conjugate heat transfer (CHT) and computational fluid dynamics (CFD) techniques were combined and applied in the computational analysis. Only the two obstacles in rectangular shape: co- and cross-flow configurations were validated against experimental results, as the other two has no experimental data available, but similar CFD methodology was applied. The impingement jet cooling enhancing obstacles were aligned transverse to the direction of the impingement jet cross-flow on the target surface and were equally spaced on the centre-line between each row of jet holes transverse to the cross-flow. Also, one heat transfer obstacle was used per impingement jet air flow in order to see the level of heat transfer augmentation of each one. &nbsp;The CFD calculations were carried out for an air mass flux G of 1.08, 1.48 and 1.94 kg/sm<sup>2</sup>bar, hence for each obstacle grid geometry, three computations were conducted and therefore a total of twelve different computations for this investigation. These high mass flux used, are only applicable to the regenerative combustor wall cooling applications. Validation of the CFD predictions with the experimental data indicates good agreement for impingement gap flow pressure loss (ΔP/P) and the surface average heat transfer coefficient (HTC),&nbsp;h. Other predictions were also carried out and were for locally average X<sup>2</sup>&nbsp;HTC, hole exit pressure loss, turbulence kinetic energy (TKE), flow-maldistribution, Nusselt number (Nu) and normalized temperature, T* or thermal gradient. It was concluded here that the rectangular-pin obstacles have the highest exit hole and impingement gap pressure loss, but with low heat transfer as a result of higher flow-maldistribution. Dimple obstacle has the lowest heat transfer, but is because most of the heat is taken away (or sucked in) by the dimple pot. The main effect of the obstacles was to increase the heat transfer to the impingement jet surface, but the dimple surface was predicted to have a very poor performance, with significantly reduced target wall heat transfer and thermal gradient.</p> A. M. El-Jummah G. E. Andrews J. E. J. Staggs Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 314 328 PROPERTIES OF SELF-COMPACTING MORTAR MADE WITH SORGHUM HUSK ASH AND CALCIUM CARBIDE WASTE AS BINDER http://azojete.com.ng/index.php/azojete/article/view/610 <p>The quest for the development of alternative and more sustainable construction material stemmed out from the current global concern on issues relating to global warming and green house effect. In recent time, research direction has shifted towards the use of agro-industrial waste as complete replacement of ordinary Portland cement. In this study the effects of the blends of sorghum husk ash (SHA) and calcium carbide waste (CCW) on the fresh properties of self compacting mortar was investigated where various tests were carried out which included physical and chemical properties of the constituents materials, Flow cone test for paste, Mini v-funnel flow time and Mortar flow spread test for determination of saturation dosage of HRWR for self compacting mortar made with sorghum husk ash and calcium carbide waste as binder, were carried out. Then developments in the compressive strength of the hardened mortar were determined at 3, 7, 14, 28, 56 and 90 days. The study revealed that SHA sample have high Silicon dioxide (SiO<sub>2</sub>&nbsp;(84%) while CCW is majorly Calcium oxide (CaO(66%).The optimum saturation dosage of &nbsp;High Range Water Reducer &nbsp;(HRWR) determined from Flow cone test and Mini-v-funnel was 3.5%. The 70/30 (SHA/CCW) shows the highest mortar flow spread of 290 mm compared to the control (295mm).The agro-industrial binder exhibited good binding properties at a slow hydration rate. Analysis of the compressive strength results show that 70/30 (SHA/CCW) proportion has the highest value of 14.08 N/mm2 at 90 days. Self compacting mortar made with SHA/CCW combinations as binder can be adopted for use in masonry work as it conforms to type N of ASTM C270 mortar</p> I. O. Hassan O. W. Bolaji J. O. Adedapo Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 329 341 INVESTIGATION OF THE MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF WELDED API X70 PIPELINE STEEL http://azojete.com.ng/index.php/azojete/article/view/611 <p>The mechanical properties of pipelines particularly those in marine environments are influenced by corrosion activity of seawater throughout their service lives. The degree to which these properties are influenced in seawater compared to those exposed to air needs to be better understood. In this study, the chemical composition of API X70 pipeline steel plate, microstructure and mechanical properties of the welded joints of same steel plates exposed to ambient air and seawater respectively were investigated. It was found that the base metal consisted of manganese (0.51wt% Mn), low carbon content (0.051 wt% C) and small quantities of alloying elements such as vanadium (0.021wt% V), molybdenum (0.118 wt% Mo), chromium (0.240 wt% Cr), copper (0.002 wt% Cu), and a carbon equivalent (CE IIW) of 0.38. Scanning Electron Microscope (SEM) showed that the microstructure of base metal sample has large grains formed in packets which have certain crystallographic orientation but contain submicron grains arranged in a chaotic interlocking manner. The tensile tests performed using a UNITED type universal testing machine confirmed that the yield strength of the base metal was 573.045MPa which conforms to API standard for X70 steel pipe. The manual metal arc (MMA) welding technique was applied to produce the welded joints. &nbsp;For the welded joints exposed to ambient air at room temperature, the yield strength was 680.624MPa while the compressive strength was 1500.2MPa, and the impact energy at -10°C was 112.68J. Air tests referred to tests conducted in the laboratory at room temperature. For the welded joints exposed to seawater for 12 weeks, the yield strength was 609.154MPa while the compressive strength was 1219.34MPa, and the impact energy at -10°C was 61.48J. The above results for air and seawater exposures were used to determine the environmental reduction factors of the two environments. &nbsp;Hardness tests conducted using Vickers hardness tester revealed variations in hardness across the base metal, the HAZ and the weld, with the weld having the highest average Vicker’s hardness value (223.8HV) followed by the base metal (217.3HV) and the HAZ had the least (214.5HV)</p> T. M. Ike O. Adedipe S. A. Lawal M. S. Abolarin O. A. Olugboji Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 342 354 VALUE MANAGEMENT CONCEPT IN CONSTRUCTION PROJECTS DELIVERY IN KANO STATE http://azojete.com.ng/index.php/azojete/article/view/612 <p>Construction projects delivery play an important role in the economic development of any nation. Nevertheless, review of project documents in Nigeria and Kano State in particular indicates that, the design of these projects is such that the whole life-value is not achieved. One of the suitable tools for the compensation of this drawback is the use of Value Management (VM) technique. This paper presents that the use of organized framework for the VM technique in the initial phase of a project generates good ideas that has the capacity to increase the project value. The objective of the study is to investigate the application of the VM in public construction projects, identify the constraint factors limiting its application, and suggest ways to expand its use in the built environment. Questionnaire survey methodology, addressed to government ministries and agencies actively involved in construction and to project management consulting firms, was utilized. A total of 94 questionnaires responses were received from 7 ministries and agencies. Another 13 responses were received from randomly selected consulting firms. The data was analyzed using SPSS 23 version. &nbsp;It was found that value management as a formal programme is not applied to the development of construction projects in Kano State. Lack of knowledge about the value management technique and its financial and technical benefits was found to be among the constraint factors of its application. Furthermore, lack of government demand on VM, unfamiliarity with VM technique, and unavailability of experts to perform were determined to be the top constraint factors. Therefore, it is recommended that the promotion of value management use can be achieved by creating awareness among the construction stakeholders, gaining top management support, providing training programmes, guideline, and financial incentives to procurement administrators</p> Alhassan Dahiru Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 355 364 EFFECT OF PROCESSING PARAMETERS ON SOLVENT OIL EXPRESSION FROM LOOFAH SEEDS (LUFFA CYLINDRICA L.) USING RESPONSE SURFACE METHODOLOGY http://azojete.com.ng/index.php/azojete/article/view/613 <p><em>Luffah cylindrica</em>&nbsp;plant grows in the wild, around uncompleted buildings and fenced walls. The percentage oil composition of its seeds is about 30% oil. The research focused was the extraction oil from loofah seed using a solvent extraction methodology. Optimum conditions for oil extraction were determined using Response Surface Methodology of Central Composite Rotatable Design. A total of 20 experimental runs were used to investigate the optimum condition considering three independent variables at five levels each: extraction temperature (55, 60, 65, 60, 75ºC), seed/solvent ratio (0.04, 0.05, 0.06, 0.07, 0.08 g/ml) and extraction time (4, 5, 6, 7, 8 hr.). An empirical model equation that could be used to forecast oil yield as a function of the independent variables was developed. The optimum oil yield obtained was 27.43% at the extraction temperature (74.05ºC), seed/solvent ratio (0.05 g/ml) and extraction time (5.35hr). The analysis of variance showed that extraction temperature and time had significant effect on oil yield (p = 0.05). The interaction of the independent variables with oil yield gave R<sup>2</sup>&nbsp;and R<sup>2</sup>&nbsp;adj. values of 0.98 and 0.93, respectively. The result showed that the selected independent variables had a significant effect on oil yield, thus an optimum condition was established.</p> R. A. Busari T. D. Akpenpuun M. O. Iyanda Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 365 374 SHEAR WALL PROVISION INFLUENCE ON MEDIUM RISE MULTI-STOREY FRAMED BUILDING IN MAIDUGURI http://azojete.com.ng/index.php/azojete/article/view/614 <p>This study compares the aerodynamic behaviour of medium rise multi-storey frame structures with and without shear walls using the local wind gust of Maiduguri&nbsp;(47m/s) as primary data. The wind assessment was carried out in accordance with recommendations of British Standard and other relevant specifications. Analysis of the structural system was carried out using Extended Three-dimensional Analysis of Building System (ETABS) software; where the forces, maximum floor drifts and stresses are obtained and compared. The result shows that, the displacement fora 15 storey building with shear wall was 91.44% less than same without shear walls while with increasing storey height, the differences reduce; for example, the displacement for 20 storey building with shear wall showed 81.5% lesser than same building without shear wall. This signifies that building with shear wall resist aerodynamic load more efficiently principally due to the influences of the rigidity and strategic locations of the shear wall in the building. The shear walls are usually effective in stabilizing displacements on medium rise multi-storey buildings subjected to lateral forces from wind, seismic and explosive to satisfy serviceability criteria of H/500 stipulated by most conventional standard</p> A. M. Alkali L. O. Onundi K. Mohammed Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 375 384 APPLICATION OF STEARIC ACID FOR SOLAR THERMAL ENERGY STORAGE IN A DOUBLE COMPARTMENT SOLAR BOX COOKER http://azojete.com.ng/index.php/azojete/article/view/615 <p>Energy storage in some form is the need of the hour to even out the mismatch between energy supply and demand. Thermal Energy Storage (TES) system employing a phase change material (PCM) has been widely considered as an effective way to store and retrieve energy due to its high heat storage capacity at almost constant temperature during the phase change. In this work, an energy storage system was designed to study the heat transfer characteristics of stearic acid (as a phase change material in a double compartment solar box cooker (DCSBC) fabricated using wooden materials with high thermal energy storage system. In order to analyze the various characteristics of the PCM, the Bureau of Indian Standards (BIS) was used throughout the experiment. Investigations were performed to determine the first and second figure of merits&nbsp;(F1 and F2) of compartments 1 and 2 (C1 and C2) simultaneously. The results for F1 were found to be (C1= 0.14 and C2= 0.15) and F2 were (C1=0.47 and C2= 0.4) while the overall thermal efficiency of the cooker after water boiling test for C1 with 2.5kg and C2 with 3kg of water were deduced to be 77% for C1 and 92% for C2 after six hours of the load test, showing considerable temperature increase and extension of heat retention making possible to cook the dinner and even breakfast the next day.</p> M. B. Maina S. Shodiya A. T. Abdulrahim Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 385 394 MODIFICATION AND PERFORMANCE EVALUATION OF ACTIVE SOLAR DRYER FOR HIGH MOISTURE TOMATO CROP http://azojete.com.ng/index.php/azojete/article/view/617 <p>In this study, two active solar cabinet dryers with capacity each to dry 10 kg of fresh vegetable were fabricated. The drying cabinet of the first dryer was fabricated using plywood and is refer to as unmodified dryer (UM) while the second dryer with white transparent glass and is refer to as modified dryer (MD). The performances of the two dryers in terms of total drying time, final moisture content obtained and preservation of nutritive values of the dried vegetable were investigated using tomato as sample. Ten kilogram of the sample were sliced to about 1cm and neatly arranged in the drying chamber for the drying process in a period of two days (8am-6pm). The results revealed that there was a reduction in total drying time of 2.5 hours, from 18 hours in UM to 15.5hours in MD which corresponds to reduction in moisture content (wet basis) from initial value of 92% to final moisture content of 12- 13.3%. The results further revealed that maximum drying rate of 6.9 kg/h was observed for UM dryer and 9.4 kg/h for MD both obtained within 8 hours of drying time. &nbsp;The average temperature recorded in the MD was found more than the UM by about 13°C at 3.00pm. The efficiency of the MD in terms of reduction in total drying time was 13.89% higher than the UM. Proximate analysis result shows the composition of the dried tomato in the UM to be protein, 0.76%; lipids, 1.00%; vitamin E, 0.0083%; moisture content, 13.3%; ash, 0.60% and crude fiber, 1.80%. However, the composition of dried tomato in MD were protein, 0.69%; lipids, 0.90%; vitamin E, 0.0080%; moisture content, 12%; ash, 0.58% and crude fiber, 1.78%</p> K. Mu’azu A. Mahmood B. Inuwa I. G. Sadiq M. U. Shitu Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 395 405 PREDICTION OF BUS TRAVEL TIME ON URBAN ROUTES WITHOUT DESIGNATED BUS STOPS IN MAKURDI TOWN, BENUE STATE, NIGERIA http://azojete.com.ng/index.php/azojete/article/view/618 <p>The lack of information on bus travel time in Makurdi town to enable trip makers plan for journeys is seen as a challenge in recent times. This study developed a multiple linear regression model for predicting bus travel time along bus routes in Makurdi town. Specifically, the study assessed bus travel time on routes without designated bus stops, examined geometric features of bus routes, assessed bus dwell time and travel speeds in a heterogeneous traffic stream on routes in Makurdi town. It&nbsp;developed and validated a model for the bus travel time. Field survey focused on the major bus routes in Makurdi town which included; High Level roundabout to School of Remedial Studies junction (HL-SRS), High Level roundabout to Federal Medical Centre junction (HL–FMC), Wurukum roundabout to Coca Cola Complex (W-CCC) and Wurukum roundabout to Welfare Quarters junction (W–WQ). Independent parameters examined on the sites for model development included; bus route length, bus travel speed, average dwell time at random stops for pick-up and alighting of passengers, bus headway, the total number of cross and Tee intersections along the bus route, volume of motorcycles, private cars and trucks in the traffic stream, while the dependent variable was bus travel time. Based on the built model, 15 minutes approximately was established as the average bus travel time for all bus routes in Makurdi town assuming all other variables have zero magnitude. Goodness of fit test of the model yielded significant value for coefficient of determination (R<sup>2</sup>&nbsp;= 0.952) and the use of Artificial Neural Network (ANN) method for validating the model also confirmed it accuracy at 93% approximately. It was therefore concluded that, bus travel time on major routes in Makurdi town could be accurately estimated using the built multiple linear regression model provided all essential input parameters of the model are used. The establishment of designated bus stops along bus routes within Makurdi town to minimise bus dwell frequency and for accurate estimation of bus travel time, as well as erection of travel information bill boards along bus routes stating average bus travel time to inform commuters that have high value of travel time were recommended</p> P. T. Adeke O. J. Inalegwu K. Jirgba Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 406 417 DETERMINATION OF MAIGANGA LIGNITE COAL COMBUSTION CHARACTERISTICS FOR APPLICATION IN THERMAL POWER PLANT USING STANDARD MATHEMATICAL MODELS http://azojete.com.ng/index.php/azojete/article/view/619 <p>This paper presents determination of Maiganga lignite coal combustion characteristics for application in thermal power plant using standard mathematical models. The problem statement was that Nigeria cement plants uses rotary kiln coal burner despite its associated drawbacks such as sudden explosion and incomplete combustion. Fluidized bed technology has less of the drawbacks associated with rotary kiln coal burner. The integration of Maiganga coal in mathematical models will increase accurate prediction of operating variables useful in design and sizing the components of fluidized bed thermal power plant. The methodology of the study includes utilization of established numerical models based on energy balance and fuel properties for Maiganga lignite combustion. The coal was fired in a pilot atmospheric fluidized bed combustor (FBC). The results obtained include the theoretical air required per kg of Maiganga lignite was 7.4, at an excess air of 10% and maximum mass of air supplied per kg of Maiganga lignite of 8.82. The time for burn out of particle sized 0.4 mm was determined to be 2.64 min, with burning rate of 0.23 kg/min (3.8 g/s). The ignition temperature of 797 K and fuel power of 84 kW for Maiganga coal were determined for the pilot FBC in this study. The Maiganga lignite fuel, air and sorbent flow rates through the fluidized bed combustor were predicted to be 14.2 kg/hr (0.23 kg/min), 202.4 kg/hr and 1.26 kg/hr respectively. The combustion performance evaluation of the fluidized bed combustor had specific firing rate for the lignite at graded particle size of between 0.2-1.12 mm at bed temperature of 1173 K was 2.8 g/m<sup>2</sup>s, air-fuel ratio of 23 and equivalence ratio of 0.45. The above results are similar to coal burnout time of 3 minutes and equivalence ratio of 0.40 in an atmospheric fluidized bed combustor in the literature. Hence, above parameters can be used to design and model a safe ignition and good combustion characteristics in other lignite fired power plants similar to that of Maiganga lignite coal</p> I. I. Ozigis M. T. Zarmai Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 418 434 A REVIEW OF OPTIMIZATION APPROACH TO POWER FLOW TRACING IN A DEREGULATED POWER SYSTEM http://azojete.com.ng/index.php/azojete/article/view/620 <p>Power Flow Tracing (PFT) is known to be the best method in the allocation of charges to users of transmission systems, generators and loads, in a deregulated environment. The optimization approach to PFT produced better results than other methods because it considers the physical power flow results and electrical constraints of the system. A brief review of the optimal power flow concept, PFT techniques, and the deterministic and non-deterministic optimization methods applied to PFT are presented. The paper also highlighted the future trends of hybrid optimization approach to PFT. It is recommended that more research work should be directed on the hybrid optimization methods to solve PFT problems.</p> M. A. Tijani G. A. Adepoju K. A. Hamzat M. A. Sanusi Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 435 448 DEVELOPMENT OF A LABORATORY AIRBAG MODEL TO CUSHION THE EFFECT OF VEHICLE TYRE BURST WHILE IN MOTION http://azojete.com.ng/index.php/azojete/article/view/621 <p>The incessant rate of traffic accident as a result of tyre burst on our roads from the motor vehicle necessitated the development of this airbag to cushion the effect of tyre burst. The development of this laboratory airbag model is such that the airbag is incorporated into the rim (i.e. on the rim, inside the tyre). &nbsp;This allows the vehicle balance for some time until the driver is able to maneuver and park the vehicle safely. &nbsp;The frame of the airbag model was made of 0.5 mm ply wood cut into six (6) pieces and to form the box. A hole was drilled at the front to give space for motor to be used as a prime mover. The shaft produced from a 30 mm diameter mild steel rod was machined on a lathe machine to 25 mm diameter and cut to length of 10 mm. The calculated resultant stress upon impact was 83.96 MPa. The contact area and airbag thickness was 0.258 m<sup>2</sup>&nbsp;and 2.8 mm, respectively. A mini inflator was selected and actuated with the aid of an infrared sensor; it took less than six (6) seconds to actuate the shape airbag. The laboratory model was powered by a DC source and tyre burst signals were transmitted wirelessly through a control system</p> A. B. Hassan A. Musa A. Babawuya I. Yahuza Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 449 460 PERFORMANCE AND ECONOMIC ANALYSIS OF KAINJI HYDROPOWER PLANT IN NIGERIA http://azojete.com.ng/index.php/azojete/article/view/622 <p>In this study, performance and economic evaluation of Kainji Hydropower Station in Nigeria from 2008 to 2017 was carried out. Data including total energy generated (MWh), station service consumption (MWh), total energy sent out to the grid (MWh), average inflow rate (m<sup>3</sup>/s) and average gross operating head (m) were obtained from the efficiency department of the Hydropower station from the year 2008 to 2017. Mathematical models were used based on some key parameters which include: Capacity Factor, Plant Use Factor, Availability, Power Generated and Economic Cost of Outages and Operations. The result reveals that the average power generated within the period under review was 363.53MW, with a maximum of 476.95MW in 2010 and 292.44MW in 2014 as against the installed capacity of 760MW. The Capacity Factor of the plant was between 11.04% (2014) and 40.51% (2008) as against industry best practice of between 50% to 80%. The Plant Use Factor ranged between 38.48% in 2014 to 62.76% in 2010 as against acceptable value of 95% and above, while the plant availability hovers between 28.69% in 2015 and 91.26% in 2009 as against the recommended standard of 99.99%. The study further reveals that the revenue loss due to system downtime was ₦169,134,293,297. This revenue loss is about 66.82% of the revenue generated which is by no means a huge amount. The above values call for the need of a total overhaul of the generating plant in order to salvage the terrible state of these plants.</p> I. K. Okakwu A. S. Alayande O. E. Olabode Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 461 469 LOADING ECCENTRICITY ISSUE ON THE PERFORMANCE OF REINFORCED CONCRETE COLUMNS http://azojete.com.ng/index.php/azojete/article/view/623 <p>Column is a structural element that transmits floor and beam loads to the foundation safely if properly designed. It is mostly loaded axially or eccentrically at the column-beam interface. Although several research articles are available on column performance (both eccentric and axial), but there is a behavioural challenge on a column loading position parallel to the axis in relation to the flexural reinforcement requirement for Reinforced Concrete (RC) column. This paper looks inward to address the challenge by providing an understanding on the complete behaviour of RC Column flexural requirement in relations with load and its point of application for both short and slender columns. This study uses a numerical data for the column analysis under varied loads and eccentricities values, and numerical deformation and stresses determination using ABAQUS. The Finite Element analysis (FEM) result indicates that increasing column axial load leads to an anticipated higher flexural reinforcement to enhance the column capacity, and is rational. Additionally, the established behaviour between the flexural reinforcement requirement and loading eccentricity for a rectangular column can be predicted easily using established linear relations for both column types considered in this study. Moreover, the Finite Element Method analysis result for the short column similarly indicates an interesting relationship where 16 % change in load value will translate to about 16 % change in deformation value irrespective of either axial or eccentrically loaded points.</p> Kachalla Mohammed Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 470 478 CEMENT STABILIZED STRUCTURAL FOUNDATION LATERITIC SOIL WITH BONE ASH POWDER AS ADDITIVE http://azojete.com.ng/index.php/azojete/article/view/628 <p>Investigation on the potentials of bone ash powder on cement stabilized structural foundation was carried out in this paper. The aim of the study was to discover local waste material as complement for cement to reduce construction cost. Three soil samples were collected from different borrow pits in Ile-Ife and Ibadan, Nigeria called sample A, B and C. Preliminary tests such as the natural moisture content, specific gravity, grain size analysis and Atterberg’s limits were performed on the samples at their natural states and when stabilized at the condition of 8, 8 and 6% cement for samples A, B and C respectively. Engineering tests such as compaction, California bearing ratio (CBR) and undrained traixial were also performed on them at their natural states, when stabilized with optimum cement and when bone ash powder (BAP) was introduced at 2, 4, 6 and 8% to the samples. The results of the engineering tests showed that BAP increased the maximum dry density (MDD) of all the samples. With the optimum cement content kept at 8% for samples A and B and 6% for sample C, the values increased from 1687.89 to 2219.05 kg/m<sup>3</sup>&nbsp;and 1634.12 to 2174.71 kg/m<sup>3</sup>&nbsp;at 4% in samples A and B respectively and 1521.59 to 1620.70 kg/m<sup>3</sup>&nbsp;in sample C at 2% BAP content. The unsoaked CBR values of all the cement stabilized samples dropped with BAP contents. The values dropped from 4.79 to 1.79%, 3.88 to 2.31% and 4.84 to 2.43% respectively in samples A, B and C. However, the shear strengths of samples A and B increased from 604.77 to 740.09 kN/m<sup>2</sup>&nbsp;and 317.73 to 616.05 kN/m<sup>2</sup>&nbsp;respectively. It was therefore concluded that BAP is not an effective additive on cement stabilized structural foundation soil, except in the compaction and shear strength characteristics.</p> O. A. Adetayo O. O. Amu A. O. Ilori Copyright (c) 2019 Faculty of Engineering, University of Maiduguri 2019-06-01 2019-06-01 15 2 479 487