African Journals Online
Global Journal of Engineering Research

DR. ANIEKAN OFFIONG
Department of Mechanical Engineering, University of Uyo, Nigeria

&

I. C. EZEMA
Department of Mechanical Engineering, University of Nigeria, Nsukka

This paper presents the development of an integrated production inventory model for multistage serial system. The model seeks to determine simultaneously the optimal production and procurement policies through minimization of time averaged variable cost of production. The cycle concept of instantaneous multistage production inventory system is extended for non-instantaneous production and integrated with concept of inventory models with cost changes. Integer multiple parameters are used as a check factor for cost minimization. A numerical example is also presented.

KeyWords Inventory, Production, Optimization, Modeling

BY FRANCIS B. OKOKON

DEPT. OF AGRICULTURAL/FOOD ENGINEERING UNIVERSITY OF UYO, UYO

Samples of 100g clean, mature, freshly washed melon seeds were dried at intervals of 1/4, 1/2, 1 and 2h in an air-oven at 60^O C. The experiments were carried out with five different bulk samples of melon seeds. The moisture content of the seeds at each drying stage was determined.

The moisture loss in grams per kilogram dry matter(gkg^-1 DM) and the percentage shrinkage(%) of the melon seeds when dried from 10 moisture content levels to 25.6, 21.8, 19.2, 15.3, 10.1 and 7.4 % moisture content(wb) were determined.

The study showed that fresh melon seeds dried to 7.4% moisture content(wb) lost 539.2 grams of moisture per kilogram dry matter and the percentage shrinkage of the seeds was 33.9%. Graphs of moisture loss in grams per kilogram dry matter were plotted against percentage shrinkage. A straight line relationship was found to exist between the moisture loss and shrinkage of melon seeds dried down to 7.4% mc(wb).

Key words: Drying, moisture loss, shrinkage

EZE R. A. M.

Dept. of civil Engineering, University of Port-Harcourt, Port-Harcourt. Rivers state, Nigeria.

The finely ground seeds of Brachystegen Eurycoma (Achi Seed) was used in the treatment of sewage sludge. It has been found to improve sludge filterability and compare favourably with the traditional ferric chloride conditioner. The optimum dosage for each sample can be determined by drawing a tangent to the corresponding curve of each sample at the point where there is a sharp break between the straight and curvilinear potion. In this work, the optimum value for Brachystegen Eurycoma is 21.5% (0.4g/cm3) and for ferric chloride is 25% (0.5g/cm3). The foregoing results show that ferric chloride is still a better conditioner. However, during sludge filtration, cake and filtrate concentration increased with increasing dosages of the Brachystegen Eurycoma sample. This indicates that it would be useful as a conditioner if the primary product of filtration is the procurement of low filtrate concentration or high quality cake.

Key words: Brachystegen Eurycoma, Coagulation, Sewage Sludge, Filtration and Sludge Dewaterability number (SDN)

HYMORE, F. K. and *WARA, S. T.

FACULTY OF ENGINEERING, UNIVERSITY OF BENIN

* FACULTY OF ENGINEERING UNIVERSITY OF UYO

* CORRESPONDING AUTHOR

The effect of the anti-oxidant (hydroquinone) on the breakdown voltage of palm olein samples was studied. The oil samples had different acid values resulting from the different degrees of neutralization treatments given. The hydroquinone addition ranged from 0.23 to 1.13 weight percent of the oil.

The hydroquinone had a positive effect on the breakdown voltage of the oil samples. The increase in the breakdown voltage was rapid at low concentrations of the hydroquinone with the increase tending towards an asymptotic value at higher concentrations. the effect of the hydroquinone on the breakdown voltage was also dependent on the acid value of the oil. Oil samples with lower acid values had sharper increases in their breakdown voltages. Percentage increase in the breakdown voltage of 66.67(vis-à-vis the additive-less samples) was recorded for oil sample of acid value of 1.515 mg KOH/g oil and containing 0.45% by weight hydroquinone.These results show that the one major problem (oxidative stability) in the use of vegetable oil as transformer oil can be overcome without an adverse effect on their electrical properties.

Key words: Breakdown voltage, Anti-oxidant, Palm olein, Neutralization, Acid value.

J. J. WAI, AND M. T. LILLY

DEPARTMENT OF MECHANICAL ENGINEERING
RIVERS STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY
P. M. B. 5080, PORT HARCOURT.

This paper identifies surface finishing (grinding) as a major engineering process in production industries and that emery cloth otherwise know as "sand paper" is used for this purpose. The grinding process is discussed in details.

The materials and their sources requires for the production of the emery cloth are discussed and also the physical properties of the materials are considered.

The paper discusses the manufacturing stages of the cloth. Three main stages were identified — sand preparation, backing paper preparation and the emery cloth production. Finally the require quality control processes were considered, a detailed cost analysis was carried out and conclusions were drawn.

Keywords: Emery Cloth, materials production, cost

DR. ANIEKAN OFFIONG
DEPARTMENT OF MECHANICAL ENGINEERING
UNIVERSITY OF UYO, NIGERIA

The development of a computer based maintenance management system is presented for industries using optimization models. The system which is capable of using optimization data and programs to schedule for maintenance or replacement of machines has been designed such that it enables the maintenance department control all jobs associated with plant maintenance and breakdown. It predicts the time to failure of designated plants and caters for the replacement analysis of some capital equipment. The system provides all the functions necessary for the control of maintenance spares. The system also provides complete details of the operation to be performed and parts to be used in a given maintenance job. The implementation of the system has been successfully carried out in a case study.

Keywords: Maintenance, replacement, computerization, spares, inventory.

L. UYIGUE
DEPARTMENT OF CHEMICAL ENGINEERING,
UNIVERSITY OF PORT HARCOURT.
CHOBA, PORT HARCOURT.

Managing oil and gas industrial environment requires constant monitoring of the effluent discharges from such industries. The essence of such monitoring is to ascertain the level of compliance of such industries with the pollution control guidelines set by regulating agencies.

In this work, the effects of refinery effluent discharge on the physico-chemical parameters of the stream water has been studied, using treated effluent water discharged from the Port Harcourt Refinery into the Ekerekana Creek in Okrika as reference. Samples were collected at the discharge point into the Creek and subsequently at 500 metres and 1000 metres down stream.

The samples were analysed for physico-chemical parameters such as pH, TDS, TSS, COD, Oil and Grease, Temperature, Cations (Pb²⁺, Fe (total), Cu²⁺ , Cr⁶⁺, Ca²⁺, and Mg²⁺) and Anions (PO^3-₄, NO^-₃, SO^2-₄ and Cl ^- ) . The results showed that Oil and Grease, COD, Cations (Pb²⁺, Fe (total)) and temperature were affected by dilution, and are stated as follows: oil and grease, 24 to 7mg/l; Iron (Fe (total)), 1.0 to 0.16 mg/l; lead (Pb²⁺), 0.035 to 0.006 mg/l; COD, 7 to 1mg/l and temperature, 24.1 to 22.0^oC.

Keywords: Effluent water, Concentration, Dilution, Physico-chemical parameter, Pollutant.

K. M. Oghenejoboh and E. J. Akpabio

Department of Chemical & Petroleum Engineering University of Uyo, Uyo.

Effective use of local energy source by the industrial sector is of vital importance economically and environmentally. Strategies are suggested for better management of industrial energy consumption and use. Cogeneration, waste heat use, industrial integration are some strategies that can be employed to enhance effective energy use and minimize waste heat. Savings can be made by government on initial power generation costs by leveling out power consumption and reducing peak consumption rates. This the government can do by enforcing a time—of—day tariff. Consumer awareness of the strategic importance of energy use can significantly contribute to encouraging industries to pursue energy saving policies.

Key Words: Co-generation, integration, energy, discounted price, buffering

FELIX F. UDOEYO AND PONMAH I. RINDAP