| 1 |
Author(s):
G.B. Nyior, A.K. Oyinlola, O.B. Oloche, S.B. Hassan .
Page No : 1-6
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AN INVESTIGATION INTO SOME PROPERTIES OF REINFORCING STEEL BARS MANUFACTURED BY NIGERIAN SPANISH ENGINEERING COMPANY, KANO.
Abstract
Some properties of steel bars for concrete reinforcement produced by Nigeria Spanish Engineering Company, Kano were investigated. The properties investigated were chemical composition, yield strength, tensile strength, percent elongation at fracture, and hardness. The results obtained were compared with standard values set by the Standards Organisation of Nigeria (SON). The steel bars under investigation did not carry any specification, contrary to the requirements of the SON. The comparisons were based on grade 410HD.
Two of the investigated samples had carbon compositions of 0.38% and 0.28%, which are within acceptable limits while the third had carbon composition of 0.47%, which is above the acceptable maximum of 0.39%, however, they all had high amounts of residual elements. The samples all met the minimum yield strength requirement of 410N/mm2 with percent elongation values greater than the minimum acceptable limit. There was lack of uniformity in the chemical composition and properties of products of different product batches.
| 2 |
Author(s):
S. A Yaro, A. Kasim.
Page No : 7-12
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DETERMINATION OF THE LIBERATION SIZE AND AMENABILITY TO BENEFICIATION BY GRAVITY SEPARATION TECHNIQUES OF AGBADO-OKUDU IRON ORE USING SINK-FLOAT HEAVY LIQUID ANALYSIS
Abstract
This paper presents the work carried out on the determination of the liberation size and amenability to beneficiation by gravity separation technique of Agbado-Okudu iron ore deposit using heavy liquid analysis. The results of the chemical analysis of the ore gave the composition of the four important elements/compounds in the ore as follows- 37%Fet (Total iron content), 43.18% SiO2, 0.03% P2O5 and 0.15%S. The results of the size/assay analysis revealed both the iron and silica to be uniformly distributed in the coarser size fractions, which makes it very difficult to achieve complete liberation of the iron bearing minerals from the gangue mineral (silica) at coarse particle sizes. The results of the heavy liquid test gave the optimum liberation size of the iron bearing minerals from the gangue(silica) to be -90+63μm size fraction which suggests that, the comminution schedule of the ore should target crushing and grinding to (–90 + 63μm) size fraction prior to beneficiation.
| 3 |
Author(s):
I. S Sintali, G. Egbo.
Page No : 13-18
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INVESTIGATION ON THE CHEMICAL AND PHYSICAL PROPERTIES OF DAPCHI, NGALA AND GWOZA SILICA SAND FOR GLASS MAKING
Abstract
Suitability of commercially viable silica sand deposits located in Dapchi, Ngala and Gwoza- semi-arid region of Borno and Yobe states of Nigeria has been assessed based on chemical and physical characteristics of samples collected along the stream sides in these locations. The results obtained were assessed on comparative basis with the standard glass making requirements. The Dapchi and Ngala samples have higher percentage values of silica (93.6% and 92.46% respectively) acceptable for glass making. However, the percentage of Iron oxide content in them was relatively high (1.59% and 1.20% respectively), thereby limiting their application for colour and amber glasses production. Both the Chemical and Physical properties of Gwoza silica sand deposit were above the required level for application in glass making industry.
| 4 |
Author(s):
A. A Umar, F. Muzaffar .
Page No : 19-28
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DESIGN AND DEVELOPMENT OF A SELF-ADJUSTING METAL-SPINNING TOOL
Abstract
The development of a spinning tool that operates on a spring force mechanism as an auxiliary source of power to form malleable metal sheets is being presented in this paper. The tool was designed to produce axi-symmetric articles from malleable metal sheet on conventional lathe machine. It is capable of deforming circular metal sheets in the thickness range of t 0.5mm and diameter d 36cm. Dish and cone shaped articles were produced using the developed tool with high surface finish and quality.
| 5 |
Author(s):
G. Egbo, H. Dandakouta.
Page No : 29-37
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VALIDATION OF THERMAL MODEL FOR A SOLAR PARABOLIC CONCENTRATOR (SPC)
Abstract
This paper presents comparative analysis between; experimental results obtained using a solar parabolic
concentrator (SPC) model TE. 38 and simulated results obtained using a developed energy equations for solar
parabolic concentrator. The experimental aspect employed SPC model TE 38, on to which a receiver assembly
constructed with available sourced materials was mounted along the focal line. Hourly temperature changes of the
enveloping glass-cover, the absorber-tube and the fluid are recorded and system efficiency calculated. Developed
energy equations are used to predict hourly temperature changes of the enveloping glass-cover, the absorber-tube,
the fluid and system efficiency. The developed energy equations are validated since the performance of the practical
results and the predicted results R2 values are 80.4% for the enveloping glass-cover, 98.9% for the absorber-tube,
96.4% for the fluid and 98.2% for system efficiency.
| 6 |
Author(s):
M. Abdulwahab, I.A. Madugu, O.B. Oloche.
Page No : 38-43
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THE EFFECT OF CONCENTRATION OF MANGANESE ON THE CORROSION SUSCEPTIBILITY OF Al-Si-Fe-Mn ALLOY SYSTEM IN HCl SOLUTION
Abstract
An investigation on the effect of Manganese contents on the corrosion susceptibility of As-cast and Age-hardened Aluminium-Silicon-Iron-Manganese (Al-Si-Fe-Mn) alloy system in hydrochloric acid (HCl) solution at room temperature (280C) was carried out using weight loss method of analysis. The alloys containing 0.1, 0.2, 0.3, 0.4, 0.5% Mn and control were produced and sand cast into cylindrical test bars then age-hardened. The as-cast and age-hardened samples were machined to corrosion test coupons and immersed into 0.5M HCl solution for 20 days. The results of the corrosion test revealed that the corrosion rate decreases as the percentage addition of Manganese increased for both conditions (as-cast and age-hardened) with the age-hardened alloys exhibiting better corrosion resistance throughout the exposure time. This may be attributed to the formation of intermetallic compounds.
| 7 |
Author(s):
I. A Madugu, S. A Yaro.
Page No : 44-49
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CHEMICAL AND PHYSICAL CHARACTERISTICS OF AGBAJA AND ITAKPE IRON ORE SINTER BLENDS
Abstract
The chemical and physical characteristics of sinter blends produced from Agbaja iron ore concentrate of high phosphorus and low silica and Itakpe iron ore concentrate of low phosphorus and high silica were determined in this work. The two ores were concentrated using conventional beneficiation techniques and then blended in the ratios of 10-70% Agbaja and 90-30% Itakpe. The blends were mixed with coke breeze, limestone and moisture to produce fluxed sinters. The physical and chemical characteristics of the produced sinters vis-a-visa abrasion resistance, shatter index, tumbler index, reducibility, reduction decrepitating and chemical composition were determined. The results obtained revealed that, the physical and chemical properties of the produced sinters compared favorable with minimum blast furnace specifications. However, the sinter with 10% Agbaja and 90% Itakpe possesses physical and chemical properties that are close to the specified properties of sinter for use in the blast furnace for Pig iron production. Therefore, sinter blend with 10% Agbaja and 90% Itakpe iron concentrates can be recommended for use in blast furnace for production of pig iron.
| 8 |
Author(s):
W. A SHITTU, D. D DAJAB.
Page No : 50-61
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SITE-SPECIFIC PREDICTION OF RECEIVED SIGNAL POWER USING MODIFIED TWO-RAY APPROACH
Abstract
This paper presents a model for the prediction of cellular mobile radio received signal power in built-up environments using modified two-ray approach. The classical two-ray model, hitherto reported in the literature, is a basic ray tracing approach, which consists of a direct ray, and a ground-reflected ray, and is most suited for use in open/rural environments that are free of obstructions usually found in highly built urban environments. The modified two-ray model reported in this paper uses direct rays and wall-reflected rays, up to a maximum order of three reflections, for prediction of received signal power in a site-specific built-up environment. The prediction values generated with the model are then validated with measurements using a Cellular Mobile Radio test receiver (Sagem OT 160). A good agreement was found between the prediction and measurement values as the mean difference between these values was only 12.60 dBm which compares well with 6.02 dB between predicted and measured path loss already reported in the literature.
| 9 |
Author(s):
J. KATENDE, M. S. HARUNA.
Page No : 62-80
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POWER SYSTEM CHARACTERISATION OF THE NIGERIAN SHIRORO COMPLEX
Abstract
The paper presents power system analysis of the Shiroro Complex using ERACS power system analysis software. The study was carried out under different loading and generation conditions, modeling philosophy, power flows and fault level. In all cases, the result obtained demonstrates the need for additional power generation facility and means of voltage compensation at receiving ends. For operational convenience and efficiency, this paper proposed regionalization in transmission and analysed one of the regions in Nigeria as a case study. This is to position the region as a suitable candidate for application of FACTS devices.
