S. A Yaro, T. Dungka, F. Asuke.
Page No : 1-8
BENEFICIATION OF MURO IRON ORE DEPOSIT BY MAGNETIC SEPARATION METHOD
In this work the possibility of up-grading a sample of iron ore from Muro iron ore deposit to a concentrate suitable for the production of pig iron using the conventional blast furnace process by dry magnetic separation method was investigated. The Muro iron ore deposit is located in Toto local Government area of Nasarawa State. The Iron ore deposit has an estimated reserve of 3.8 millions tonnes scattered over three different locations with an average iron content of 31.6% (Fe ) and silica content of 56.57%(SiO2). The concentration tests were carried out using a laboratory scale magnetic separation machine at a magnetic field intensity of 20 ampere per meter. The result of the concentration test s revealed that, an optimum grade of 57.19%Fe and recovery of 81.86% at particle size fraction of -80 + 63μm and with least value of 8.26% silica content could be attained. Based on the results obtained the concentrate produced might be used in iron production using the Blast furnace process route. However the economics of the process needs to be looked into as grinding the bulk of the ore directly to -80+63μm may be very expensive in the case of iron ore being a low priced commodity in the international market.
E.N. OGORK, M.K. RIMI.
Page No : 9-15
‘KARGO’ (POLIOSTIGMA THONNINGI) FRUITS POWDER AS ADMIXTURE IN CONCRETE
The paper presents the findings of an investigation into the admixture properties of ‘Kargo’ (poliostigma thonningi) fruits powder (KFP) in concrete. The investigation was conducted on grade 20 concrete and also on cement paste with varying percentage addition of KFP of 0%, 0.25%, 0.5%, 0.75% and 1.0% respectively. The results of the study show increase in compressive strength with increase in percentage addition of KFP up to 0.5% KFP, the strength then decreases with increase in percentage addition of KFP. The highest strength were obtained with 0.5% addition of KFP of 31.11 N/mm2, 33.48 N/mm2, 37.78 N/mm2 and 38.70 N/mm2 at 3 days , 7 days, 28 days and 56 days respectively. This represented 17.66%, 17.72%, 4.94% and 4.91% increase in strength from strength of control sample (0% addition of KFP) respectively.
The study also shows that the use of KFP in cement paste decreases initial and final setting times with increase in percentage addition of KFP. The initial and final setting times obtained for cement paste with 0% addition of KFP were 75 minutes and 132 minutes, respectively. The mean percentage decreases of initial and final setting times from control samples of cement paste, (0% addition of KFP) were 31.42%, 68.95%, 89.65%, and 93.54% for cement paste with 0.25%, 0.5%, 0.75% and 1.0% addition of KFP, respectively.
KFP concrete is susceptible to water absorption and drying shrinkage, hence not considered suitable for use in environment where it will be subject to ingress of water or chemicals.
KFP could be considered as an accelerating admixture for up to 0.5% addition by weight of cement that is approximately 1.9 Kg per m3 of concrete.
A. A. UMAR, A. Bashir.
Page No : 16-21
DEVELOPMENT OF AN OPTIMUM MIX OF MOLDING MATERIALS FOR CASTING PURPOSES USING CHALLAWA RIVER BED SAND
The Challawa river bed sand commonly used by Kano founders was analyzed. Various additives were mixed with the sand and analyzed with the aim of determining an optimum mix in preparing molding sand that can produce a very good sand casting. The physical properties were investigated based on the addition of various percentages by mass of water and Kaolin clay. The result of the test show that the Challawa river sand mixed with 4% water and 20% clay produces a molding material with a good range of properties that can result in a good casting. This mix is thus recommended for use of founders.
M. L. Usman, A. T. Abdulrahim, G. M Ngala.
Page No : 22-27
AN ASSESSMENT OF LOCALLY AVAILABLE ETHANOL AS ALTERNATIVE FUEL IN NIGERIA: A CASE STUDY OF GASOLINE ENGINE PERFORMANCE
Locally available ethanol in a Nigeria city was tested as fuel on a gasoline engine generator, 450VA rating. The performance of the engine using ethanol was compared to its performance when using petrol and petrol – ethanol mixture fuels at room temperature (30oC). Experimental results show that maximum power output was recorded by using petrol fuel. Not withstanding, the performance of the engine using ethanol and petrol-ethanol mixture fuels were found to be closely similar to its performance using petrol fuel despite no modification to the engines carburetor. This shows that locally available ethanol is an effective fuel in running small gasoline engine in Nigeria. Hence development of ethanol industry in Nigeria is highly recommended.
H. Dandakouta, G. Egbo .
Page No : 28-37
CORRELATION FOR THE CONVECTIVE HEAT TRANSFER WITHIN THE AIR IN THE CAVITY OF A COMPOUND PARABOLIC CONCENTRATING COLLECTOR
The heat transfer processes governing the performance of a solar compound parabolic concentrator (CPC) with
evacuated receiver envelope employed for hot water generation were studied. The results showed that the convective
heat transfer was dominant and that the contribution of the radiation heat transfer from the receiver tube to the
overall heat transfer from the collector is insignificant. An empirical correlation of the natural convection heat
transfer within the enclosed air surrounding the enveloping glass tube of the collector has been proposed. The
correlation expressed in the form 0.35
yielded a linear plot of the Nu – Ra relationship
over the range of Ra values 3.84 x 103 ≤ Ra ≤5.65 x 104.
Page No : 38-43
FEASIBILITY STUDY OF WIND FARMS: A CASE STUDY FOR KANO, NIGERIA
The technical and economical feasibility of a potential wind farm to be sited in Kano, Nigeria has been investigated
in order to evaluate profitability and investment opportunities. For technical consideration, wind and turbine energy
capabilities are computed. For economical consideration, two different scenarios namely, University as Sole
Developer (SD), and an Independent Power Producer (IPP) cases, are investigated and compared with respect to Net
Present Value (NPV), Internal Rate of Return (IRR), and Pay Back Period (PBP) criteria. It is concluded that for the
wind regime of this site, the 200 kW rated turbine is preferred to any other rated turbine to be installed in a farm
under each scenario. The energy sale price is calculated as low as 11.05 Naira/kWh for the IPP scenario.
Profitability analysis shows that, larger installed capacity with lower rated power wind turbines present shorter pay
back period for the investment.
Page No : 44-52
THE EFFECT OF DONKEY-DUNG ON THE PROPERTIES OF LATERITIC SOILCRETE BLOCKS
This paper reports the findings of an investigation into the effect of donkey-dung on lateritic soil stabilized blocks.
Two major groupings of the lateritic soil samples commonly used in construction work were selected and treated
with 0%, 2.5%, 5%, 7.5%, 10%, 12.5%, and 15% of finely ground donkey-dung dropping as additives. About 72
soilcrete block samples were moulded and cured for 28day and performance tests done for moisture absorption,
resistance to water abrasion and compressive strength.
The tests results showed that increasing the percentage addition of the donkey-dung in the lateritic samples up to 10-
15% improved remarkably the compressive strength, the resistance to water abrasion and reduction in dry shrinkage
and water absorption qualities of the blocks.
The strength improvement of the two samples at 15% donkey-dung is about 1.52N/mm2 which is greater than the
minimum strength requirement of 1.5N/mm2 recommended by Nigerian Building and Road Research Institute, and
hence the block is suitable for low cost building project.
Yaro, S.A, Aigbodion, V.S.
Page No : 53-59
EFFECT OF TEMPERING ON THE MECHANICAL PROPERTIES OF LOCALLY PRODUCED ALUMINIUM BRONZE
An investigation into the effects of tempering on the mechanical properties of as-cast locally produced aluminium
bronze was carried out. The alloy was produced and sand cast into cylindrical bars at the foundry shop of the
National Metallurgical Development Center, Jos. The as-cast bars were cut and machined into tensile, impact and
hardness test samples. The machined specimens were heat-treated at 850OC, soaked for three (3) hours and then
rapidly quenched in water before tempering at temperatures of 450OC, 550OC and 650OC respectively. The tensile
strengths, hardness values and impact energy (toughness) of the both the heat-treated and as cast samples were
determined. It was observed that tempering significantly increased the tensile and impact strength (toughness) of the
alloy with an appreciable increase in hardness. However, it is worth noting that the resultant mechanical properties
of the heat-treated alloy depend on the phases present in the microstructure after hardening and tempering, as the
presence of substantial reprecipitates of the beta martensite in the already formed alpha and gamma phases during
tempering greatly enhances these mechanical properties.
Page No : 60-68
DESIGN, CONSTRUCTION AND TESTING OF INTERCOM SYSTEM
This paper presents the design, construction and testing of a simple multi-station, intercom system for use by a master and remote stations. All the electronic circuitries are contained in the master station while a remote station contains only a loudspeaker, a push – button switch and a capacitor. A call facility was incorporated in the system which allows the master station user to call a remote station and vice – versa. A display unit, made up of LEDs is provided on the master station console, which indicates to the master station user, a particular calling remote station. The display unit and the call facility are connected in such a way that the use of one push button switch provided at the remote station activates them simultaneously. The constructed unit has one master station and two remote stations with provisions to increase the number of substations. The system is built around some popular and cheap ICs so as to provide cheaper alternative to the imported types.