African Journals Online
Global Journal of Engineering Research

Volume 1, No. 2, 2002
Abstracts

ADAPTATION OF NATURAL GAS FOR MOTOR FUELS IN NIGERIA TRANSPORT SYSTEM

Oghenejoboh, K.M. and Akpabio, E. J.

Chemical & Petroleum Engineering Department
University of Uyo, Uyo.

In recent years, as a result of limiting reserve of crude oil and the clamour for the deregulation of the petroleum sector of the nation's economy, there is need to look beyond liquid fuel (gasoline, diesel) as vehicular fuels. The viability of adapting natural gas for motor fuels had been presented. Natural gas as automobile fuel has a multiple of advantages over liquid fuel. These include high octane number, less negative effects on engine parts, low toxicity of effluents. (i.e. low CO, NO_X, and lead emissions.) Experiences of other countries that are presently using natural gas as automobile fuel are reviewed along with the efforts put in place by Nigeria through the Nigerian Gas Company (NGC) Limited to experiment the project. The need of government through the NGC to be fully involved in the planning and execution of a retrofit plan to optimize pipeline network and supply service of natural gas to refueling and refilling stations is also emphasized. The public on the other hand requires enlightenment on the need to convert their vehicles to gas/gasoline powered, and incentives given for patronizing natural gas filling stations. A cohesive interplay of both national and corporate interests in policy formulation and implementation will harness effective distribution and utilization of natural gas within the Nigeria socio-economic sector.

Key words: Gas, Fuel, Automobile, Technology, Project.

EFFECTIVE SEPARATION OF GALENA CONCENTRATE FROM THE MIXTURE OF GALENA AND QUARTZ BY TABLING

O. Ojo and B.M. Olaleye

Department of Mining Engineering
Federal University of Technology
P.M. B. 704, Akure
Ondo State, Nigeria

Separation of a clean galena (lead sulphide) concentrate from the mixture of galena and quartz by tabling operation has been investigated. The Nigerian Lead ore composed mainly lead sulphide and quartz.

Tabling method was employed on the ore as a method of gravity concentration. The mineral constituents of the ore were successfully separated based on the relative specific gravities of the constituent minerals. The results of the work are useful to mineral processing industries for the separation of Nigerian lead ore and will also serve as database for similar industrial processing plant and similar ore deposits.

Keywords: Galena, Quartz, Separation, Concentration, Tabling.

ON THE MOLAR POLARIZABILITIES OF BINARY MIXTURES FROM TERTIARY BUTYL ALCOHOL ISO-PROPYL ALCOHOL AND TOLUENE AT 298K

L. Uyigue

Department of Chemical Engineering,
University of Port Harcourt, Nigeria

ABSTRACT

Three pairs of binary mixtures from pure grade liquids of Tertiary –Butyl Alcohol (TBA), lso-Propyl alcohol (IPA) and Toluene (TOL) were prepared at 298k and 1 atm. Subsequently, the densities, mole fractions and refractive indices of the mixtures and their pure components were obtained at 298k. The average molar polarizabilities (^_AV) and excess molar polarizabilities (__) for the binary mixtures were obtained.

The results showed linear trends for average molar polarizabilities over the entire composition range for the three binary mixtures. Positive excess molar polarizabilities dominated the composition range of the three binary mixtures, but it is however absolutely dominant in the Tertiary- Butyl Alcohol (TBA) and Toluene (TOL) mixture.

The magnitude of the induced molar polarizability for the three binary mixtures at 298k are in the order of Tertiary- Butyl Alcohol (IPA) and Toluene (TOL) > Iso-Propyl Alcohol (IPA) and Tertiary –Butyl Alcohol (TBA) > Iso-Propyl Alcohol (IPA) and Toluene (TOL) mixtures.

Keywords: Binary Mixture, Molar Polarizability Temperature, Molar Refractivity, Mole Fraction.

DEVELOPMENT OF A MAINTENANCE SCHEDULING MODEL FOR A GROUP OF MACHINES

Aniekan Offiong

Department of Mechanical Engineering,
University of Uyo, Uyo, Nigeria

ABSTRACT

This paper presents the development of an efficient method for use in obtaining the best time between coordinated overhauls for a group of machines. The method is capable of stating the overhaul frequency of each machine within this time period. For convenience in the formulation of the model, maintenance schedule was divided into two parts, namely minor and major maintenance schedules. During a minor maintenance, an individual machine is checked and reset, while during a major maintenance, all machine are checked and reset simultaneously. Generally, their model determines the best value of the time between major maintenance and frequencies of minor maintenance, for each machine within this time span. In order to minimize the total cost of repairs and production. A numerical application of this development model in a case study is presented.

Key words: Maintenance, modeling, scheduling, optimization.

RELATIONSHIP BETWEEN SLUDGE DEWATERABILITY NUMBER AND CARMAN'S SPECIFIC RESISTANCE

R.A M Eze

Dept of Civil Engineering,
University of Port Harcourt, Choba, Rivers State.

ABSTRACT

A representative of a sludge sample collected from the same source was filtered under the same environmental condition and the result analysed with two different concepts. One method of analysis uses Sludge Dewaterability Number, while the second employed the Carman's Specific resistance concept in sludge filterability. Two plots are employed, one shows a process of specific resistance determination while the other indicates how Sludge dewaterability number can be determined. A critical examination of the two plots reveals that a relationship might exist between the two concepts. Also, the analysis of the filtration results obtained using both the old and the new concepts, confirms that both Sludge Dewaterability Number values and the Specific resistance values decrease with an increase in the conditioner dosages. This is a mark of good coagulation with an increased filterability when conditioner dosages (ferric chloride) are increased in filtration process. The new equations have therefore shown some good relationships between sludge dewaterability number and specific resistance, which are in line with the original concepts. It has also been shown that sludge dewaterability number is directly proportional to the area of filtration and the square root of the specific resistance. This varies according to the diameter of the filtrate collecting cylinder and the area of filtration that is used in the determination of specific resistance (r) values.

Key words: Sludge, Coagulant, Coagulation &Filtration, Sludge Dewaterability Number, and Specific Resistance,

ANALYSIS AND COMPUTER SIMULATION OF A NATURAL CONVECTIVE SOLAR- HEATED ANIMAL BUILDING

Department of Agricultural Engineering
University of Nigeria, Nsukka

ABSTRACT

A model has been developed to predict the outlet air temperature and air flow rate from a solar collector based on the theory of thermal buoyancy. A high capacitance solar collector directly coupled to an animal building absorbs solar radiation, which heats up air and forces entry into the building by convection.

In order to test the validity of predictions of the model measured outlet air temperatures of the solar collector are compared to the predicted values and the results are presented. The predictions of outlet temperature and air flow rate agree reasonably well with experimental data, differences being of less than 1.5% significance.

Key words: Solar collector, thermal buoyancy, outlet air temperature, and Air flow rate

Felix F. Udoeyo and Matthew Y. Turman

Department of Civil Engineering, University of Uyo, Uyo, Nigeria

ABSTRACT

The result of a study on some characteristics of laterite- cement mix containing termite mound soil (50% by weight of laterite) as replacement of laterite are presented in this paper. The study showed that laterite-mound soil mix stabilized with 6% cement could serve as a base course for roads for agricultural trafficking in rural areas where mound soils are abundant. At 6% cement stabilization the unconfined compressive strength (UCS) of 1.57 N/mm² and a California bearing ratio (CBR) of 330% were obtained. The durability of the mix at this cement content was also found to be satisfactory with 87.7% resistance to loss in strength, and 1% weight loss and 1.15% volume change after 12 wet- dry cycle test.

Key Words: Mound soil, Pavement, Road-base, Material

THE ADSORPTION OF CAUSTICIED CASSAVA STARCH FLOCCUOLANT GOETHITE, KAOLINITE AND QUARTZ IN RELATION TO FLOCCULATION

Linus O. Asuquo

Department of Mechanical Engineering, University of Uyo, Uyo.

ABSTRACT

The adsorption of caustized cassava starch on goethite, Kaolinite and quartz has been investigated using model 5500 Atomic Absorption / inductively coupled plasma spectrometer to determine the residual concentrations in the solution .The effect of such variables as pH and starch concentration on adsorption has been studied. Also the effect of reagentization time on the flocculation pH of pulp and starch concentration on the flocculation behaviour was studied. Both polymer adsorption and the flocculation of goethite, kaolinite and quartz are enhanced as the pH decreases .The amount of polymer adsorbed rises at first and then approaches a saturation value.

KeyWords: Adsorption, Flocculation, reagentization.

ON THE ARTIFICIAL SEMICONDUCTOR MATERIALS

Department of Physics, College of Science & Agriculture
University of Abuja, P. M. B. 117, Abuja, FCT, Nigeria.

For about the last three decades, semiconductor technology began to make its most apparent impact in Solid State Electronics. The field of photonics, which combines laser physics, electro-optics and nonlinear optics has expanded tremendously. Notably, modern light wave communications exemplify photonic systems. Here, optical signals are generated, modulated, transmitted, and detected before they are transformed to electrical form for final use. Optical processing of information has notably been found to possess several advantages over electronic processing, which must usually be done serially and is limited in speed by the broadening of pulses in interconnecting wires and also limited in density by cross talk between those wires. Optical systems capable of handling very large quantities of data is now awaiting only the development of convenient digital optical logic elements with low switching energy. An ideal material for opto-electronic applications as mentioned above should be able to transform light into current and vice-versa for emission and detection. The material should also exhibit large electronic and optical nonlinearities that would allow one to use it as a transistor and optical gate. These materials which are currently internationally studied are presented in this paper.