1 |
Author(s):
OSUNDE Z. D..
Page No : 1-6
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EFFECTS OF MOISTURE CONTENT ON THERMAL CONDUCTIVITY OF CASSAVA TUBER
Abstract
Thermal conductivity of peeled and unpeeeled cassava tuber was determined using the line heat source method. In this method a steady heat flux is applied to the sample using a line heat source located inside the sample, then the temperature rise at some point in the specimen resulting from applied flux is measured. The cassava tubers used are of TMS96/1431 and TMS96/1087 varieties. Thermal conductivity was measured at different moisture content of the tuber. The result shows that the thermal conductivity increases with an increase in moisture content for the two varieties and for both peeled and un peeled cassava tubers. Thermal conductivity of the cassava tubers ranged from 0.043 to 0.085 for TMS96/1431 and 0.038 to 0.098 for TMS96/1087 for peeled and un peeled cassava tubers respectively. A distinct difference was observed between the thermal conductivity of the two cassava varieties at all moisture content. The peeled cassava had a slightly lower thermal conductivity.
2 |
Author(s):
Salami, A. W, Yusuf, I. T.
Page No : 7-15
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APPLICATION OF PROBABILITY DISTRIBUTION MODELS ON STUDYING THE CHARAC-TERISTICS OF METEOROLOGICAL VARIABLES IN IBADAN AND ITS ENVIRONS
Abstract
This study aims at studying the characteristic of meteorological variables in Ibadan and its environs by using prob-ability distribution models. The data were collected at IITA (International Institute of Tropical Agricultural Re-search and Training), Ibadan and subjected to different probability distribution analyses to determine the best fit probability functions for each variable. The variables considered include rainfall, evaporation, relative humidity, temperature, sunshine hour and wind speed, while the probability distribution models adopted are Gumbel, Log-Gumbel, Normal, Log-Normal, Pearson type III and Log-Pearson type III distribution functions. Mathematical equ-ation were established and used to predict the variables. Goodness of fit tests such as chi-square, Fisher’s test, cor-relation coefficient, and coefficient of determination were carried out to determine the reliability of the predicted values. The model that satisfies the statistical tests conditions mostly was selected as the best fit model. The study revealed that rainfall, wind speed and sunshine hour are best fitted by Log-Pearson probability distribution model, while for relative humidity, evaporation and temperature, the best fit probability model is log-Gumbel, Log-Normal and Pearson type III respectively.
3 |
Author(s):
Rufai, I. A..
Page No : 16-19
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ENVIRONMENTAL ASSESSMENT OF RENEWABLE FUELS TECHNOLOGY
Abstract
The paper is a review of the benefits of renewable fuels in general and a study of the environmental impacts of biofuels in particular. An attempt has been made to show that the use of biofuels may not be environmen-tally friendly as is being portrayed by their advocates. It is a fact that energy generation using fossil fuels produces many important pollutants including nitrogen oxides, sulfur oxides, hydrocarbons, dust, soot, smoke, and other particulate matter. It is believed that if carbon dioxide levels continue to increase, the planet will become warmer and will most likely result in a variety of impacts including sea-level rise, ex-treme weather events, and an increased frequency of droughts in inland agricultural zones. Biofuels such as alcohols, biogas, biodiesel and its esters appear to be a more viable alternative, especially for use as fuels in diesel engines. The replacement of fossil fuels through increased utilization of biofuels produced in a sustainable manner, can contribute towards a cleaner environment, reduction of greenhouse gas emissions and mitigation of climate change. However, the mechanized agricultural production technology necessary for large scale production of energy crops is accompanied by intensive tillage and fertilizer application. This production system is not environmentally friendly in the real sense of the word, as it is characterized by potential threats of environmental pollution and degradation.
4 |
Author(s):
MOMOH O. A, SALIHI A..
Page No : 20-28
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APPLICATION OF MARKOV ANALYSIS TO MANPOWER PLANNING IN A REFINERY: A CASE STUDY OF KADUNA REFINING AND PETROCHEMICAL COMPANY LIMITED (KRPC)
Abstract
Manpower disposition in many organizations in Nigeria especially government owned establishments is not usually determined based on Job analysis and corresponding workforce requirements. The paper applies Markov Analysis to aggregate manpower requirements based on analysis of internal staff movements due to retirements, promotions and resignation in the maintenance department of Kaduna refining and Petrochemical Company Limited (K.R.P.C). Basic data on maintenance task duration, Management approved staff disposition, actual staff disposition and estimated maintenance staff requirements determined from manpower utilization analysis and internal staff movement formed the basis for the Markov Analysis and the determination of required workforce. Staff turnover estimated from historical records of staff movement is used as representative of probability transition to determine the number of staff in each category that would leave the system and the subsequent expected vacancies created. Markov analysis of the effects of internal staff movement is used to determine the required workforce and the number to be recruited or laid off.
5 |
Author(s):
E.N. OGORK, T. A. IBU.
Page No : 29-34
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PROPERTIES OF POWDERED LOCUST BEAN POD (“MAKUBA”) CONCRETE
Abstract
This paper presents a research into the use of locust bean pod powder (Makuba) as an additive in concrete. Makuba is a powdery product obtained from Locust bean pod when pounded. It is found mainly in the Northern part of Nigeria with scientific name Perkia Filicoidea. Two grades of Concrete (20 and 30) were investigated to determine the suitability of Makuba as an additive in Concrete. To each grade of Concrete, Makuba was added in varying concentration of 0%, 2.5%, 5.0% and 10% cured in water and tested for compressive strength after a period of 7, 28 and 56 days respectively. The chemical analysis carried out on Makuba showed that Makuba contains at least 15 elements. Ranking top are: Magnesium (24%), Potassium (20%), Calcium (17%), Aluminum (15%), Sodium (12%), Chlorine (10%), Radium (1%) and others below 1% in concentration. The results on the compressive strength of the concrete samples revealed generally a decrease in strength for every increase in Makuba content. However, there was a progressive increase in strength with age up to 56 days. Moisture absorption test also carried out had revealed a corresponding increase in the moisture absorption with the percentage addition of Makuba for both grades of Concrete. It has also revealed that grade 20 concrete absorbed more moisture than grade 30 Concrete. Makuba is therefore not considered suitable as additive in concrete at percentages considered.
6 |
Author(s):
Uche, O. A. U, Abubakar, M. N.
Page No : 38-44
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INFLUENCE OF NEEM SEED HUSK ASH (NSHA) ON ENGINEERING PROPERTIES OF RESIDUAL LATERITIC SOIL
Abstract
The civil engineer is faced with arduous task of modification/stabilization when faced with problento lateritic soil in highway and other construction work, This study presents the result of experina0 investigation on the influence of Neem seed husk ash (NSHA) on the engineering properties of resid lateritic soil found along Kaduna-Kano road, Nigeria, Experimental investigation classified the untreated so as A6 or CL soil according to AASHTO and USCS classification respectively. The NSHA additions writ performed using 0, 4, 8 and 12% of NSHA by weight of dry soil thoroughly mixed. The results of the, ovoid soil showed that the liquid limit, plastic limit and the maximum dry density (MDD) decreases as the AM addition increases, whereas the plastic index and the soaked Californian bearing ratio (CBR) increases as !I NSHA content increases. This implies that the Neem seed ash (NSHA) possess the potential for use in iltt modification/ stabilization of residual lateritic
7 |
Author(s):
Mukhtar, M. M, Zubairu, I. K..
Page No : 45-50
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AN EVALUATION OF THE ACCURACY OF COST ESTIMATES IN PUBLIC BUILDING PROJECTS IN NIGERIA
Abstract
This article presents the results of a study of the accuracy of cost estimates in public building projects in
Nigeria. Data were collected from a sample of 40 completed building projects with initial cost values of
between N3.00m – N187.19m. A questionnaire survey of construction professionals was also undertaken in
which the respondents were asked to indicate their opinions on the causes of inaccurate cost estimate in
public work projects. Seventy five (75) survey questionnaires were distributed and fifty three (53) of them
were returned completed. Based on the analysis of the data collected, it was found that, public building
projects exceed their initial estimates by an average value of 5.16%. Furthermore, 65.0% of the projects
considered have their estimated costs within the limits of ±5% of the actual costs. The survey revealed that,
the main factors that influence the accuracy of cost estimates of public building projects are improper
planning, non compliance with condition of contract, incompetence on the part of the contractors, lack of
understanding of project requirements by the estimator and insufficient information related to the project
before execution. To improve on the accuracy of cost estimates, it is recommended that both the client and
the contactor should make adequate planning in terms of the resources required for the execution of the
projects at early stage, prior to the commencement of the work
8 |
Author(s):
A. A. Jimoh.
Page No : 51-56
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STRENGTH MODELLING OF AXIALLY LOADED DOKA (Isoberlinia doka) TIMBER COLUMN
Abstract
The paper presents a design procedure for axially loaded doka timber (botanical name - Isoberlinia doka), as a column or strut. Instead of the usual categorization of columns or struts into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula to cover the three categories is derived. To derive the model, an experimental program was carried out on direct axial compressive strength test on doka specimens, to obtain stress and strain data. The data were subsequently analyzed to derive the typical stress-strain equations in compression. This equation and the Euler – Engesser stress formula were used to obtain values of critical stress and corresponding slenderness ratios, which was subsequently analysed to form the proposed design equation. The equation was verified on doka columns of different slenderness ratio and which conservatively predicted the experimental ultimate load capacity of the columns
9 |
Author(s):
Gonoh B. A., Bello O. O.
Page No : 57-65
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DESIGN OF AN INFRASTRUCTURE WIRELESS LOCAL AREA NETWORK FOR A MULTI STOREY BUILDING COMPLEX
Abstract
This paper presents the design of an infrastructure wireless local area network for a multi-storey building complex. National Board for Technical Education (NBTE) secretariat complex in Kaduna has been used as a case study. A site survey of the Secretariat was conducted included network documentation, spectrum analysis and coverage analysis using NetSurveyor software. The simulation and design were conducted using OPNET IT Academic Guru. A 2.4 GHz frequency band was selected as optimum for the channels of the access points so as to avoid interference from wireless signals from nearby sources such as, nearby banks, cybercafés and corporate organizations. In addition, the coverage analysis showed that a total of fifteen (15) access points would be required to provide adequate coverage for ushers within the secretariat complex to link up to the network. It was also observed that the network follows the same pattern, regardless of the number of ushers and the medium access in use. However, the delay performance decreases before it stabilized when point coordination function (PCF) medium access functionally of the access points are disabled.
10 |
Author(s):
Gambo, A.H, Ogork, E.N, Aboshio, A.
Page No : 66-77
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WIND-INDUCED DYNAMIC STUDY OF COMMUNICATION MASTS IN NORTHERN NIGERIA
Abstract
The Stability of masts used for telecommunication purposes in Nigeria are often threatened by loads imposed on them by the weather; primarily Wind loads. This periodic load interacts with these slender structures thereby exciting a dynamic response from these structures.Failures of a number of these masts in Nigeria were recorded in the recent past. Field inspection of some of these failed masts has identified observable deformations due to vibrations and deflection of mast members leading to a progressive mode of failure as the main problem. Thus, this study assesses the dynamic stability of existing mast in Nigeria, considering the four (4) leg and three (3) leg free standing mast of heights 20m, 30m, and 40m and tip dimensions varied at 1/30th, 1/40th and 1/50th of the effective height of mast for Diagonal bracing, Zee bracing, Kee bracing and Diagonal bracing with no horizontal beam.Parametric study of the dynamic analysis results identifies the K-bracing as the most effective bracing arrangement for the tubular secton – 20mm diameter with the highest natural frequency of 0.748 Hz, 0.532Hz and 0.347Hz for 20m, 30m, and 40m effective height of mast respectively and having the least tip deflections of 106.37mm, 245mm and 471.69mm for 20m, 30m and 40m effective height of mast respectively. For the geometric stability of these masts, it was also established that given the base dimension of masts kept at 1/13th of the effectively height of masts (Chandra 1977) the tip dimensions should range between 1/35th to 1/45th of the height of mast.
11 |
Author(s):
Mohammed M.I., Bajauro A.M..
Page No : 78-82
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PHYSICO-CHEMICAL PROPERTIES OF JATROPHA OIL FROM NOTHERN NIGERIA
Abstract
Jatropha curcas Linn oil was extracted using Hexane : isopropanol mixture in a ratio of 3:2 as a solvent employing the Soxhlet extraction method. The solvent extraction of Jatropha seed kernels gave a yield of 50 g oil / 100 g Jatropha seed kernels. The physical and chemical properties of Jatropha curcas seed oil were evaluated and the results showed that it consists of 50 % (dry w/w) crude oil whose density was 0.9174g/cm3, moisture level of 0.02%, acid value (3.25 mgKOH/g), iodine value (100.62 mgKOH/g), saponification value (195.13mgKOH/g), flash Point (I55°C), Pour point (15°C), sulphur content (0.02%), distillation point (342°C), viscosity at 40°C (33.36 cSt), viscosity at 82°C=11.09 cSt, colour is yellowish (1.0). It is obvious that the properties of Jatropha oil will be comparable to those of the standard diesel oil upon further transesterified to biodiesel.
12 |
Author(s):
D. D. Dajab, S. E. Ogundapo, J. Y. Oricha.
Page No : 83-88
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COMPARISON OF EMPIRICAL AND SEMI-EMPIRICAL PROPAGATION LOSS MODELS FOR GSM IN AN URBAN ENVIRONMENT
Abstract
Empirical and semi-empirical propagation models are based on extensive measurements and observations over a particular terrain. There is the need to examine the prediction variations of the models over other environment. In this paper, the COST–231 Hata, Lee and COST-231 Walfisch–Ikegami path loss models were used as basis to analyze coverage prediction using signal strength measurement from a GSM network. This was conducted in the urban environment of Kano, Nigeria for nine base stations. The analysis of the data was used to obtain the prediction error statistics of the models. The results gave mean prediction error values of-5.2dB,-12.3dB and 4.3 dB for COST-231 Hata, Lee and COST-231 Walfisch–Ikegami path loss models respectively. These results show that on the average, the COST-231 Hata and Lee models under-predict the path loss. The COST-231 Walfisch-Ikegami model over-predicts the path loss, but provides the best results for this urban environment.
13 |
Author(s):
AGBOOLA, O. F.
Page No : 91-96
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THE EFFECTS OF CALCIUM TREATMENT ON THE SIZE AND NUMBER OF INCLUSIONS IN STEEL
Abstract
The size and number of non-metallic inclusions in 3 medium carbon steel melts of 1kg each, treated 1J-4.3g and 5g of calcium were investigated Samples. measuring 10mm x 20mm were removed Ai the casts and polished. They were then subjected to optical microscopic examination and the /?; 5 and numbers of inclusions observed were recorded. Results obtained reveal that with increasing eimm addition, the maximum inclusion si4e.decreased .from 45 to 30 microns and the number of inclusions also reduced substantially. in addition, the Iota) nwnher of inclusions decteasedfroM . :7" in the sample treated with the lowest amount nice:kiwi, to 1,917 in she sample with the highest am of calcium.
14 |
Author(s):
Aboshio, A., Ogork E.N, Balami D.A..
Page No : 95-101
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RICE HUSK ASH AS ADMIXTURE IN CONCRETE
Abstract
The paper assesses the use of rice husk ash (RHA) as an admixture in concrete in normal environment by determining the effect of addition of RHA of 0%, 5%, 10% and 15% respectively to concrete grades 20 and 30 concrete respectively. RHA used was obtained by burning rice husk obtained from a local mill in Kano. The husk obtained was sun dried, screened and burned at a temperature of 400oC in an incinerator. The ash obtained was cooled and sieved through a 425μm sieve and added as an admixture during mixing. A concrete mix design in accordance with Department of Environment (DOE), U.K (1975) method as reported by Teychem et al (1975) was adopted to proportion the constituents of both grades of RHA Concrete. Concrete mixes of both grades of concrete were prepared and the properties of fresh and hardened concrete assessed. The compressive strength of cubes of samples of RHA concrete cured in water were determined at 7, 28 and 56 days respectively in accordance with BS 1881 part 116 (1983). The results showed that the slump of RHA concrete increases with increase in percentage addition of RHA for both concrete grades. The compressive strength of samples of both concrete grades cured in water increases with addition of 5% and 10% RHA respectively but 5% addition of RHA had a better improvement in strength. Further increase in addition of RHA (15%) decreased the strength of RHA concrete.
15 |
Author(s):
B. A. Gonoh, Danliti Inusa.
Page No : 102-107
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RELIABILITY EVALUATION OF 11KV DISRIBUTION NETWORK FOR GWARINPA HOUSING ESTATE, ABUJA
Abstract
This paper presents the reliability assessment of three (3) 11KV feeders for Gwarinpa distribution network, through the computation of customer based reliability indices: System Average Interruption Duration Index (SAIDI); System Average Interruption Frequency Index (SAIFI); Customer Average Interruption Duration Index (CAIDI); Average System Availability Index (ASAI) and Average Service Unavailability Index (ASUI) as well as other relevant reliability parameters. This aimed at improving awareness among distribution system planning and operation personnel in reliability issues and application, thereby improving the overall system performance and customer satisfaction. Data was obtained from the Gwarinpa office of Power Holding Company of Nigeria (PHCN) Plc for the period of five years (2002 – 2006). Matlab and Microsoft excel are used in the data analysis and representation of the results. The paper also analyzes the contribution of system component failures to the unavailability of power supply for the period under study. The results of the findings have shown that most of the power outages are due to failures of overhead lines, protective/ isolation equipments and failures of lightening arrestors. Network reconfiguration, good workmanship and use of good quality system components would address these problems.