THE EFFECT OF CALCIUM CARBONATE AT LOW VOLUME FRACTIONS ON THE MECHANICAL PROPERTIES OF POLYPROPYLENE/CALCIUM CARBONATE NANOCOMPOSITES

¹Chinedum Ogonna Mgbemena, ²Nelson Obinna Ubani, ³Chika Edith Mgbemena

¹Department of Mechanical Engineering, Nnamdi Azikiwe University, Awka

² Department of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike

³ Department of Industrial/Production Engineering, Nnamdi Azikiwe University, Awka

Email: edumgbemena@yahoo.com

ABSTRACT

Polypropylene/Calcium Carbonate nanocomposites were prepared by melt compounding of the Polymer material and melt mixing with the Calcium carbonate nano-fillers at filler loadings of 5%, 10%, 15% and 20%.The samples evaluated were the stearic acid coated and uncoated nano-fillers. The results of the study showed that the addition of CaCO₃ nano-filler have resulted in the improvement of the mechanical properties of the Homo Polypropylene, mainly the Young Modulus. The tensile strength and elongation at break of Polypropylene was slightly reduced with the incorporation of the nano-filler. The Young Modulus increased for Calcium carbonate volume fractions for both the coated and the uncoated grades for filler concentrations up to 5%.Stearic acid coated fillers showed the highest Improvement in the above tensile properties at this low volume fraction .It is important to note that the maximum tensile strength occurred at 5% Volume fraction and as the volume fractions increased both the Tensile strength and elongation decreased and in contrast, the Young Modulus increased.

DURABILITY OF CONCRETE CONTAINING FLY ASH (FA) IN AGGRESSIVE ENVIRONMENT

¹J.O. Afolayan and ²A. Y. Alhassan

¹Department of Civil Engineering, Federal University of Technology, Akure, Nigeria

²Department of Civil Engineering, Federal Polytechnic, Idah, Nigeria

Email: joafol@yahoo.com; alhassanay2@yahoo.com

ABSTRACT

This paper examines the strength and durability of Portland-pozzolana cement (PPC) concrete. Different composition of PPC samples were prepared, sample A comprises  Ordinary Portland Cement (OPC) and served as the control sample, samples B, C and D comprises OPC and fly ash (FA) in the ratio 90:10, 80:20, 70:30, respectively. Concrete cubes were then made using these samples, and were cured in water after which compressive strengths were tested at 7, 14, 21, and 28 days. The rest of the cubes were then immersed in solution of 2.5% CuSO₄ and solution of 2.5% NaCl for a period of 3 months, after which their strengths at 30, 60 and 90 days were tested for durability. The results of the chemical analysis on the pozzolana (fly ash) indicated that the total percentage of iron, silicon and aluminum oxides is above the minimum of 70% specified by ASTM for pozzolana [1]. Though the results of the compressive strength and durability of the concrete cubes made from PPC were not higher than that of the control, they were all higher than the minimum specified standard by BS code [2]. On the average, sample D was the best PPC used in this research.

Keywords: Portland–Pozzolana Cement, Ordinary Portland Cement, Fly Ash, Compressive

Strength, Durability.

SELECTED PERFORMANCE ANALYSIS OF A ROTARY STEAM TUBE DRYER USING SPREADSHEET SIMULATION

Ugochukwu C. Okonkwo and Lazarus Chima 

Department of Mechanical Engineering

Nnamdi Azikiwe University, Awka

ABSTRACT

The primary motivation that triggered this study was when a feasible analytical solution amenable to computer spreadsheet programming was sort for, in explaining the physical configuration of the rotary steam tube dryer. An existing rotary steam tube dryer was studied from where analytical derivation of the moisture content distribution, drying rate, mass condensation rate and system efficiency were established. With the derived equations, the developed spreadsheet modules calculate and plot charts, simultaneously, illustrating the variations of the above parameters along the length of the pipe. The results generally show; that the moisture content falls steadily from inlet to outlet of the dryer and that the drying rate has an initial increase before falling along the length of the dryer. The results also show that the rate of steam condensation has an initial steep increase at the beginning of the length of the dryer, which eventually normalizes to steady state as the length advances, while the system efficiency generally increases with increase in length. This developed case was achieved with ordinary Excel array functions without the use of macros and add-ins.

Keywords: Drying, Spreadsheet Simulation, Rotary Steam Tube, Moisture Content

MAXIMUM CONVERSION EFFICIENCY OF THERMIONIC HEAT TO ELECTRICITY CONVERTERS USING MOLYBDENUM AS THE EMITTER

¹Abubakar Alkasim and ^2*Muhammad Tanko Baba

1 Department of PhysicsFederal; University of Technology, Yola;

2 Department of Mechanical Engineering; Federal Polytechnic, Mubi

E-mail: alkasimabbat @ yahoo.com and muhammadtanko@yahoo.com

ABSTRACT

An analysis of Thermionic converters of heat to electricity is made in terms of the potential difference between the top of the potential barrier in the inter electrode space and the Fermi level of the emitter, the potential drop across a load impedance connected in series to the converter, and the potential drop to the necessary electrical connection to the collector. This analysis is carried out by developing an expression with respect to the potential drops. The expression yields optimum values of load impedance, collector lead geometry and emitter work function in terms of collector voltage, emitter temperature, effective emmissivity of the emitter for both thetheoretical and practically obtain Richardson Dushman constant (usually denoted by A) for a Molybdenum metal surface. The expression developed is worked out numerically and the out come shows that (1) a low value of collector voltage is required for a high efficiency (2) a low radiation heat loss is required for a high conversion efficiency and (3) relatively low values of  emitter work function are required for maximum conversion efficiency at ordinary emitter temperature.

Key words: Thermionic converters, emitter, potential drop, Richardson Constant

OPTIMUM ORIENTATION OF PHOTOVOLTAIC (PV) MODULE FOR ELECTRIC POWER GENERATION IN OGBOMOSO AREA

Sanusi, Y.K, Fajinmi G.R and Awodugba A.O

Department of Pure and Applied Physics

Ladoke Akintola University of Technology, Ogbomoso, Nigeria

E-mail: sanusiyekinni@yahoo.com

ABSTRACT

The solar energy may be used to produce electricity using photovoltaic (PV) modules by a photovoltaic conversion. Among several factors that influence the conversion efficiency of a photovoltaic solar system is to use optimum orientation (tilt angle) of a photovoltaic module. In this work, the measurements of the optimum tilt angles are daily studied during one complete year 2007. Data treatment and analysis are carried out. The results are discussed and the optimum tilt angles of photovoltaic module for the electric power generation at LAUTECH, Ogbomoso area are determined. The maximum output power at an angle 8 degree and 12 degree for dry season (February to April) and rainy season (June to September) respectively were obtained. The results can then be used as a baseline data for the optimal utilization of a P.V module system for the electric power generation in the area of study and other areas having similar radiation characteristics.  

Keywords: solar energy, power output, tilt angle, electricity.

COMPARATIVE PERFORMANCE EVALUATION OF INTERMEDIATE GINGER PULVERIZING MACHINE WITH TRADITIONAL PROCESSING TECHNIQUE IN NIGERIA

Y. Yerima¹; *S. E. Uwadiae²; and E.M.Turu³

Department of Chemical Engineering, Igbinedion University, Okada^1,2

Department of Chemistry, KSCOE, Gidan Waya, kafanchan
E-mail: mailyerima@yahoo.com^1,3 and  suwadiae@yahoo.com²

ABSTRACT

The intermediate ginger pulverizing machine and the traditional ginger processing technique were studied and compared. The performance of the two mills was conducted and evaluated in terms of throughput, energy coefficient, pulverizing efficiency, reduction ratio, particle size distribution and losses. The test result revealed that the intermediate ginger pulverizing machine had higher values of throughput, 96kg/hr; energy coefficient 0.032 ton/hp-hr; pulverizing efficiency 80%; particle size distribution 1.18mm to 10.00mm; reduction ratio 21:1 compared to the traditional mill with 18kg/hr, as throughput and 60% efficiency.

Key words: Pulverizer, Performance, Ginger; evaluation, Technology

SIMULATING AN ARTIFICIAL INTELLIGENCE FOR HELICOPTER FLIGHT MANOEUVRE

Sunny Orike

Department of Electrical/Computer Engineering

Rivers State University of Science and Technology, Port Harcourt-Nigeria

E-mail: orike.sunny@ust.edu.ng,

ABSTRACT

The paper aims to simulate an artificial intelligence for helicopter flight manoeuvre. The methodology makes use of inverse simulation and genetic algorithms to develop a high level helicopter pilot model to fly a prescribed manoeuvre, and realisation of a multi-objective optimisation/search algorithm to converge to a human-like solution. The inverse simulation generates the controls required to fly the helicopter, while the genetic algorithms generate feasible solutions to the inverse simulation problem. The overall goal is to prescribe a manoeuvre for the helicopter and have the developed pilot find control settings that carry out the given manoeuvre. Continuous controls encoding method was implemented in flying an acceleration/deceleration manoeuvre form. The helicopter pilot was formulated as a multi-objective optimization problem with four objectives imposed as penalties. A novel approach, termed maxPenalty, compared and returned the biggest of the four penalties. The genetic algorithm attempts to maximise the fitness function, while minimising the pilot’s total workload. The work evaluates the developed model pilot in terms of performance and functional efficiency.

Keywords: Geneticalgorithms, Helicopter pilot, Inverse Simulation

THE STUDY OF CONDITIONAL PROBABILITIES AND THERMODYNAMIC PROPERTIES OF NA-K AND GA-ZN LIQUID ALLOYS

Musari Abolore A, Egunjobi, A.I, Oseni, K.J, Sodunke, M.A,

Physics/Electronics Unit,

Moshood Abiola Polytechnic, Abeokuta.

e-mail:abmus911@yahoo.ie

ABSTRACT

A model based on the calculation of conditional probabilities has been used to gain further insight into the study of energetics of Na-K and Ga-Zn liquid alloys. The model refers to as four atom cluster model enables us to observed feature of these alloys. Our calculations yield for both alloys, agreement with the experiment about the concentrations at which segregation occurs in both alloys.also the degree of segregation in Na-K is larger than Ga-Zn.

Keywords: Ordering Energy, activity, chemical short-range order, Four-atom cluster model.

EFFECT OF INTEREST RATE ON INVESTMENT AND PRODUCTION IN SMALL AND MEDIUM SCALE ENTERPRISES: CASE STUDY OF SELECTED COMPANIES IN EDO STATE

F.F. Asekhame and O.N. Aibangbee

 Department of Mechanical Engineering

Igbinedion University, Okada.

Email: oaibangbee@gmail.com

ABSTRACT

An empirical study to appraise the effect of interest rate on investment and production in small and medium scale industries is presented here. Data collected using the questionnaire administered to the various companies was analysed, using statistical tools namely Cochran Q-test and percentage analysis. The Cochran Q-test was used to analyse the part of the questionnaire that required a Yes/No response, while the percentage analysis was done to ascertain the percentage of respondents that answered a particular question. With the Cochran model applied on the responses, a computed value of Q_cal =40.722 was obtained while a value of 23.68 at 95 percent of significance was obtained from the Cochran table. With the calculated value higher than the value from the table, it can be said that the data collected during the study does not provide sufficient evidence for us to accept the null hypothesis (H_o) which argued that there are no laid down criteria for Yes/No response. Hence the alternative hypothesis which clearly depicts the reality of the questions asked was accepted.  From the percentage analysis, it was deduced that 60% of firms got their initial finance from personal resources, while 33.33% got their finance from relatives and none of the firms got its initial finance from the bank. 73.33% of the firms gave their reason for not going to the bank for their initial finance as due to high interest rate, while 26.67% gave their reason as due to lack of collateral.

Keywords: Interest Rate, Investment, Production, Entrepreneurs

EFFECTS OF CENTRIPETAL FORCE AND HIGHWAY DETERIORATION ON VALLEY CURVES OF NATIONAL HIGHWAYS (A CASE STUDY OF ENUGU – AWKA EXPRESSWAY)

Adinna B.O, Umenwaliri S.N. and Aginam C.H.

Department of Civil Engineering; Nnamdi Azikiwe University, Awka

E-mail adinnaboniface@yahoo.com

ABSTRACT

This paper investigated the reasons for the ever presence of many potholes and alligator cracks at valley curves in most national highways, using Enugu – Awka express way as a case study. From the ensuing studies carried out on the case – study highway, it was discovered that centripetal force increases the axle load of vehicles by about 20% – 30% for pavements on valley curves, thereby causing serious damage to pavements at valley curves. A visual contrast which was discovered during the investigation seriously underscores the findings: where a summit curve and a valley curve occurs at same location on the two-lane-dual carriage way, the lanes going uphill are often totally free from potholes, while those going downhill a rife with ever widening potholes. Based on the above findings, it was recommended that road designers should provide sufficient thickness of road surfacing and base courses to counter the effect of centripetal force at valley curves. This thickness should be minimum at the beginning of the curve and maximum at the center of the curve, i.e should increase with increasing centripetal force along the length of transition curve. This should be done without compromise to high quality of construction materials and workmanship.

Keywords: highway vertical curves, centripetal force , road pavement, potholes.