| 1 |
Author(s):
B. A. ADEGBOYE.
Page No : 1-9
|
SIMPLIFIED APPROACH FOR COMPUTATION OF SEQUENCE IMPEDANCES OF RADIAL PRIMARY DISTRIBUTION SYSTEMS
Abstract
The paper discusses analytical:procedures for computing sequence impedances of radial primary distribution systems. The analysis is based on two approaches. First is the Carson's approach while the second approach, developed by the author, is derived from the capacitive reactance and the inductive reactance of transmission lines and which, for the purpose of this paper, is called the InCap technique. The two techniques were applied to the Gaskiya/Town 11 distribution systems in Zaria town, Kaduna State of Nigeria. The results of the two approaches were comparatively analysed and were found to be consistent with those obtained when the techniques were applied to another distribution system. Conclusions were drawn based on the results and recommendations proposed.
| 2 |
Author(s):
OKOPI A. MOMOH, ABDU SALIHI.
Page No : 10-19
|
A PROBABILITY BASED INSPECTION MODEL FOR A RANDOMLY FAIL EQUIPMENT IN A REFINING AND PETROCHEMICAL PLANT
Abstract
Performance assessment of the Fuels Unit of a refinery has shown that soineequipment of the unit fail rand and failures are'detected by inspections. Current inspection schedules for these randomly failing equipment not based on any specifically established criteria. Sometimes inspection frequencies are high and other u inspections are very few in a period leading to undetected failures. A probability based method for obtai. optimal inspection schedule is proposed. The model recognizes the difficulties associated with quantifying costs of inspection and undetected failure generally and particularly in Manufacturing Plants in Nigeria while operating cost information is scarce and the general attitude to cost data is poor. The, failure record of 11F,AlE 1.0:W2 used to preheat Fluid Catalytic Cracking Unit (FCCU) feed to the reactor in Kaduna Relining Petrochemical Company Limited (K.R.P.C) is used for the inspection model.
| 3 |
Author(s):
ABUBAKAR IDRIS.
Page No : 20-28
|
FINITE ELEMENT SENSITIVITY OF STRIP FOOTINGS AT VARYING COLUMN MOMENTS
Abstract
In the study, displacement method.of Finite Element Analysis (FEA) was used to analyze strip footings to obtain maximum actions in designing the footings in accordance with provisions of BS8110 (1997). For this purpose, a computer program that can analyze strip footings using linear FEA was developed. Design example to demonstrate the applicability of the program was included. It was shown among other findings of a sensitivity study that as magnitude of applied colunin moment increased; area of bottom reinforcement required increased, area of top (column face) reinforcement required decreased, and area of transverse reinforcement required remained constant. Also, when the magnitude of applied column moment was doubled, the bottom reinforcement increased with an average value of 8.44%; top reinforcement decreased by about 11.47%; and the animate bearing pressure also decreased with an average value of 11.47%. Based on the results presented, top -einforcement and ultimate soil bearing pressure are the most important design variables of the strip footings .coder increases in applied column moments.
| 4 |
Author(s):
B. A. Gonoh, Oladapo Omotoso.
Page No : 29-40
|
MODELLING AND SIMULATION OF INDUCTION MACHINE: A MODULAR APPROACH
Abstract
In this paper, a modular Simulink implementation of an induction machine model is described in a step by step. ;71:roaclt. With the modular system, each block solves one of the model equations; therefore unlike black box Joh!, all of the machine parameters are accessible for control and verification purposes. Solving the model (quations, h4atlab tool, a commercial software package is used to simulate the performance of the induction ::rachine. Atter the implementation, the use of the model as induction machine is demonstrated.
| 5 |
Author(s):
O.A.U UCHE, M. ABUBAKAR.
Page No : 41-45
|
THE EFFECT OF DIFFERENT OVERLAP LENGTHS ON THE EFFICIENCY OF GLUED JOINTS IN TIMBER
Abstract
The success of timber structures depends to a significant degree on the joint details employed. This paper reports the findings of an investigation on the effect of different overlap lengths on the efficiency of glued lapped joints in timber. Five different types of overlap lengths were fabricated as follows: 40mm, 60mm, gOmm, 100mm and 120mm using Afara species, a common wood type find in the tropics. The joints were subjected to static bending, compression and tensile stress tests in the direction parallel to the grain. The tests were carried out hi accordance to ASTM D143.94, (1994); NCP 2 (1973) and BS 373 (1997). The results of the test show that the efficiency of overlap joints increases in bending, compression and tensile loading as the length of overlap increases from 40 -120mm, but decrease in efficiency was noted after 100nun overlap length in tensile load test. This implies that efficiency of timber lapped joints increases with increase in the area of contact of the joint for betiding and compression loads but is limited to an extent in tensile load conditions.
| 6 |
Author(s):
Muhammed Bashir MU'AZU, Jimoh BOYI, Yusuf JIBRIL.
Page No : 46-55
|
DEVELOPMENT OF A NEURAL NETWORK BASED SOIL EVAPORATION PREDICTION MODEL
Abstract
Meteorological conditions have a great impact on the amount of energy available in the natural world and as such play a great role in regulating evaporation from the vegetation. This work is aimed at developing a Neural Net based soil evaporation prediction model by considering the effect of such meteorological conditions as solar radiation (sunshine hours), wind speed, temperature and relative humidity (over an eleven year period from 1993 to 2003) on the ET process using Zaria as a case study. One of the signs of a good model is that the training set performance and that of the test set are fairly similar with respect to the key performance indicators. The model also performed well on the validation data. The model was then tested on the data for 2003, which was previously not used and the results obtained can be regarded as acceptable.
| 7 |
Author(s):
J. D. Jiya, J. M. Gumpy .
Page No : 56-64
|
IDENTIFICATION OF AN INDUSTRIAL OIL-FIRED POWER PLANT BOILER SYSTEM
Abstract
In this study, the Savannah Sugar Company Limited Numan, Nigeria (SSCLN) boiler system is modelled as a multivariable plant with two inputs (feed water rate and oil-fired flow rate) and two outputs (steam temperature and pressure). The plant parameters are identified based on experimental data using MATLAB system identification toolbox. The measured and simulated model outputs for temperature and pressure show a very good agreement.
| 8 |
Author(s):
YARO S. A, DUNGKA G. T.
Page No : 65-71
|
CHEMICAL AND MINERALOGICAL CHARACTERISTICS OF KOTON KARFE IRON ORE
Abstract
The chemical and mineralogical characteristics of Koton Karfe iron ore located at lgbide in Lokoja local Government area of Kogi State was investigated using X-ray diffractometer (XRD), X-ray Fluorescence Spectrophotometer (XRF), Gravimetric method of chemical analysis and Metallographic techniques. The results obtained, revealed that Pit 1 of Koton Karfe iron ore has an average total iron content (43.40% Fel), 10.14% (S102), 1.24% calcium (Ca), 0.70% manganese oxide (Mn), 0.10% and 0.0051% strontium (Sr) while pit 2 contained 0.9% Titanium (Ti), 0.16%, 26.50%Fer, 0.041% zircon (Zr), 0.0020% Niohium(Nh) and 39.413%Silica(Si02). Unfortunately, Phosphorus (1') and Sulphur (S) were beyond limit of detection in both samples by Gravimetric Method. Thin sections of the ore samples from the two Pits examined under polarized light revealed that the iron bearing minerals arc predominantly magnetite, goethite while siderite, quartz and hematite are minor in population in pit 1. Pit 2 has quartz as the major mineral, magnetite and hematite as minor while ilmenite, zireonitc and niobite are in traces. The micrograph of pill (plate 1) revealed that the ore is oolitic in nature while that of pit 2 (Plate 2) is pisolitic in nature. Based on the results obtained In• this study, Koton Karfe iron ore sample of pit I can be classified as medium grade, lost silica magnetite iron ore, while pit 2 as low grade, medium silica hematite iron ore. Finally, the combined results of chemical and mineralogical characteristics of the iron ore deposit obtained in this work have indicated that, the iron ore can be upgraded for use for the production of Pig iron by the conventional Blast furnace route at the Ajaokuta iron and steel plant.
| 9 |
Author(s):
OKOPI A. MOMOH, ABDU SALIHI.
Page No : 72-79
|
APPLICATION OF LINEAR PROGRAMMING (LP) TO A PRODUCT BLENDING PROBLEM IN KADUNA REFINING AND PETROCHEMICAL COMPANY LIMITED
Abstract
The main objective of this paper is to apply a Linear programming (LP) model to products blending problem to achieve an optimum production plan in a refinery. The model considers the existence of several processing units in the refinery, producing a variety of intermediate streams, with different pr >perks, that can be blended to obtain commercial products. The objective of the blending model is to mini ize the cost of meeting a given demand structure taking into account the cost of the intermediate stream used For blending, sale price and product demand. The refined products include premium motor spirit (PMS), Dual Purpose. Kerosene (DPK), Automotive Gas Oil (AGO) and Low Pour Fuel Oils (121:0) but only premium motor spirit is used for the model application in this paper. The production and marker scenario that was analyzed using MATHCAD provided an optimum production plan with significant profits. A sensitivity analysis was carried out to confirm the validity of the model. The results revealed that there is a very. large potential of profitability in the application of linear programming models to production planning in refineries.
