| 1 |
Author(s):
A. N. Jibril, A. N. Jibril, M. S. Abubakar, D. D. Nalado, S. K. Shittu, M. L. Attanda.
Page No : 1-8
|
DETERMINATION OF PHYSICAL PROPERTIES OF SHELLED AND UNSHELLED BAMBARA NUT (Vigna Subterranea L. Verdc.) SEEDS RELATED TO DESIGN OF DECORTICATING MACHINES
Abstract
Physical Properties of Bambara Nut are crucial for the design of harvesting, processing, transport, cleaning, sorting, separation and packaging machinery. Some physical properties of bambara nut have been assessed for both shelled and unshelled seeds. The physical properties of shelled seeds at moisture content of 11.35 percent (db) are length 14.57 mm, width 11.62 mm, thickness 10.34 mm, 70.88 percent roundness, 85.01 percent sphericity, 430.70 mm2 surface area, 634.26 g weight, 455.43 mm3 volume, 769.90 kg/m3 bulk density, 1130.63 kg/m3 solid density, 32.06 percent porosity, angle of repose 23.5º and coefficient of static friction 0.4361. The physical properties of unshelled seed at moisture content of 7.12 percent (db) are length 20.60 mm, width 16.93 mm, thickness 14.41 mm, roundness 76.45 percent, 81.60 percent sphericity, surface area 920.84 mm2, 1012.41 g weight, 321.05 mm3 volume, 355.80 kg/m3 bulk density, 993.76 kg/m3 solid density, 64.16 percent porosity, 25.5º angle of repose and 0.4782 coefficient of static friction. Statistical studies of physical characteristics showed that size (length, width, thickness, geometric diameter), porosity bulk density and surface area of shelled and unshelled seed are extremely important at 5%; weight, sphericity, volume and solid density are important at 5%; roundness, angle of repose and static friction coefficient are not important.
| 2 |
Author(s):
BELLO Ibrahim, Mohammed Jibrin Kaura, Adamu Lawan, Ashara Hadi Ahmed, Mustapha Musa Mohammed, Usman Hassan.
Page No : 9-16
|
Probabilistic Assessment of Residual Strength of Damage Reinforced Concrete Beam using Glass Fibre Reinforced Polymer (GFRP) with Flexural Deficciency
Abstract
In this work, structural reliability analysis for reinforced concrete beam strengthened with Glass Fibre Rienforced Concrete Polymer (GFRP), due to flexural deficiency as a result of corrosion was undertaken. A simply supported reinforced concrete beam was specifically used for the investigation. Corrosion rate ranging from 0.1mm/years were considered in the study. Likewise, the investigation was based on exposure time ranging from 0 to 30 years. The uncertainties in the basic design variables for bending resistance of the un-strengthened and the GFRP strengthened beam, as well as the applied bending action were fully accommodated in the analysis. First Order Reliability Method (FORM) was adopted for the computation of the safety indices. The search for the optimum safety level using FORM was enhanced by constrained nonlinear optimization strategies, using Genetic Algorithms (GA). FORM and Optimization Algorithms were developed and implemented using MATLAB Simulinks. Limit state function for flexural mode of failure was developed based on Eurocode 2 (2004). Corrosion damage model for the reinforcing steel was included in the limit state function. It was confirmed that flexural strengthening of reinforced concrete beam with GFRP can restore its capacity losses. From the study, the safety index of the beam after 30 years of corrosion exposure and before strengthening with GFRP was 0.5. However, after flexural strengthening of the beam with GFRP, using 3mm, 3.5mm, 4mm and 4.5mm GFRP sheets, the safety indices respectively increased to 1.1 (175% increase in flexural reliability), 1.7 (245% increase), 2.2 (323% increase) and 2.6 (550% increase). In conclusion, GFRP thickness of 4.5mm will achieveved a target safety index of 3.8 recommended by Eurocode 0 (2002) at a corrosion exposure time of 11 years. The research also established that for corrosion affected reinforced concrete beam, the amount of reinforcement is not significant after 30 years, since the safety of the beam tends towards zero.
| 3 |
Author(s):
S. K. Shittu, T. O. Timothy.
Page No : 17-21
|
STUDY OF DRYING CHARACTERISTICS OF BAOBAB (Adansonia digitata L.) LEAVES
Abstract
In this study, drying characteristics of baobab leave was experimentally investigated under the temperature levels of 40, 50, 60 and 70°C. The experiments were carried out so as to know the variation in moisture content of baobab leaves as a function of drying time at different temperature levels. Drying parameters that include effective diffusivity, diffusion coefficient and activation energy of baobab leaves were determined. Experimental data were fitted to existing moisture ratio models. Results show that, it took 340 min to dry baobab samples at a drying temperature of 40 °C, 160 min at 50 °C, 100 min at 60 °C and 80 min for 70 °C. Effective diffusivity of baobab leaves ranged 4.0528×10^(-13) to 1.1753×10^(-11) m^2/s within drying temperature of 40-70 oC. Diffusion coefficient and activation energy of the baobab leaves were found to be 2.290×10^(-11) m^2/s and 106.95 kJ/mol, respectively. Values of R2, RMSE and Chi-Square of all the models fitted varied between 0.717-0.997, 0.0171– 0.2893 and 0.0003–0.1046 respectively. Logarithmic model has the highest R2 and lowest RMSE and Chi-Square values. It can therefore be concluded that the Logarithmic model could sufficiently define the thin layer drying of baobab leaves.
| 4 |
Author(s):
Mustapha Jama'a Garba, Egbe Ngu-Ntui Ogork, Aaron Aboshio, Smith A, S. J.
Page No : 22-29
|
EFFECT OF COCONUT SHELL ASH (CSA) AS AN ADMIXTURE ON THE PROPERTIES OF CEMENT PASTE AND CONCRETE
Abstract
ABSTRACT
This paper presents the findings of an investigation on coconut shell ash (CSA) as admixture in cement paste and concrete. The CSA used was obtained by controlled burning of coconut shell in an incinerator to a temperature of between 600–650ºC for 3 hours, air cooled, sieved through 75µm sieve and characterized based on its oxides composition determined using X-ray Fluorescence (XRF) analytical method. The effects of CSA on cement paste were investigated with addition of 0, 2, 4, 6, 8 and 10% respectively by weight of cement. The workability of fresh prescribed 1:2:4 concrete mixes with 0.55 water-cement ratio and CSA content in the order above was determined. Harden properties of the concrete were also assessed using 100mm diameter by 200mm long cylinders mould where the concrete mixes were cast and tested for compressive and splitting tensile strengths at 3, 7, 28 and 56 days of curing in accordance with BS procedures. The result of the investigations showed that CSA is of high silicon dioxide (37.97%), aluminium oxide (22.12%), magnesium oxide (16.2%), iron oxide (15.48%) and calcium oxide (4.98%). The inclusion of CSA in cement decreased linear drying shrinkage but increased consistency, initial and final setting times and could be used as a retarder. The use of CSA in concrete showed a decrease in workability but increase in compressive and splitting tensile strengths respectively with addition of CSA up to 2%. Therefore, up to 2% addition of CSA is recommended for use as a retarding admixture and strength improver in concrete in normal environment.
Keywords: admixture, coconut shell ash, cement paste, concrete, compressive strength
| 5 |
Author(s):
Mshelia, R. B., Diso, I. S, Jibatswen, T. Y..
Page No : 30-37
|
ASSESSMENT OF GREENHOUSE GASES EMISSION PATTERN IN A TYPICAL NIGERIAN UNIVERSITY CAMPUS: A CASE STUDY OF BAYERO UNIVERSITY, KANO NEW CAMPUS
Abstract
Protection of the environment from the adverse effects of climate change has been at the front burner of discussions globally. Increase in the emission of anthropogenic greenhouse gas (GHG) emissions occasioned by industrialisation and an average increase in the income of individuals has been identified as one of the main reasons for the dramatic rise in the average temperature of the globe. Identification and reduction of the major sources of GHG emissions is key the reduction in the average world temperature. This research assessed the quantity and pattern of GHG emissions in a typical Nigerian University campus using Bayero University Kano new campus as a case study. Emissions from electricity usage, transportation, solid waste management and cooking fuels were assessed using IPCC’s guideline for assessment and reporting GHG emissions. It was found that the estimated annual GHGs emission of the Campus is 7,914tCO2e. Sixty-one percent of the campus’ emission was noted to be from electricity usage, while 30%, 7% and 1% of the campuses emissions were from transportation, solid wastes and burning of cooking fuels respectively. It was concluded that the campus’ per capita GHG emissions is lower than what is recommended by the Kyoto Protocol. Nevertheless, it can still be reduced by using electricity more efficiently, recovering energy from solid waste, provision and incentivising the use of mass transits.
| 6 |
Author(s):
MUSTAPHA MUHAMMAD, AMINA IBRAHIM KHALEEL, IBRAHIM ABDULHAMID BAKO.
Page No : 38-44
|
A Practical Implementation of Fuzzy PD Versus Fuzzy PI Based on DC Motor Speed Controllers
Abstract
This paper presents a real-time implementation of Proportional-Integral (PI) Fuzzy and Proportional-Derivative (PD) Fuzzy controllers for speed control of a DC motor. Performance of the two controllers were compared experimentally in terms of speed tracking and required control signal using step, sinusoidal and square wave commands. Based on the results obtained, it was found that the PI-Fuzzy was able to track the step command without steady state error (SSE) while the PD-Fuzzy tracked with 0.7 rev/s (14%) SSE. In terms of the control signal, the PI-Fuzzy required 5.7 V while PD-Fuzzy required 12 V. For the sinusoidal command, the results revealed that the PD-Fuzzy performed slightly better than the PI-Fuzzy in command tracking, however the PI-Fuzzy had smoother control signal. In case of the square wave command, the PI-Fuzzy tracked better whereas the PD-Fuzzy appears to be faster. PD-Fuzzy required higher control signal (11.96V) when compared to PI-Fuzzy (5.68V).
| 7 |
Author(s):
Rayyan, Z. S. Aliyu, A. D. Garkida.
Page No : 45-50
|
EFFECT OF TITANIA (TiO2) ADDITION ON THE TRANSITION TEMPERATURES OF CaO-MgO- Al2O3-SiO2 BASE GLASS SYSTEM
Abstract
CaO-MgO-Al2O3-SiO2 base glass system was developed using locally available raw materials. The local raw materials were feldspar, limestone and magnesite. Titania was incorporated into the batches in varying proportion (2,4, 6, 8, and 10 wt%) and then melted into crucibles in an electric muffle furnace. The transition temperatures of the test-melted batches were determined using Mettler Toledo DSC which was operated at a heating rate of 10 oC/ min alongside Al2O3 as reference material. The findings revealed that titania (TiO2) has a significant effect on the transition temperature of each sample in the CaO-MgO-Al2O3-SiO2 base glass system. The sample to which 0 wt% TiO2 was added has the maximum transition temperature (273oC) and transition temperature keeps decreasing on gradual titania addition ( 0wt%, 2wt%, 4wt%, 6wt%, 8wt% & 10wt%) and the sample to which 10 wt% TiO2 was incorporated has the lowest transition temperature (221oC), and this shows tremendous effect of titania on the transition temperature of the sample.
| 8 |
Author(s):
SAFIYANU Ishaq Muhammad, Aaron Aboshio, Mustapha Garba Jamaa.
Page No : 51-63
|
PARTICLEBOARD PRODUCED FROM MAHOGANY LEAVES AND GUM ARABIC AS BINDER
Abstract
The potential of using mahogany leaves particles for the production of gum Arabic bonded particleboards is reported in this paper. Fresh mahogany leaves, air-dried to a target moisture content of 10% were crushed to an average particle size of 2mm. Mix ratios of 2:1, 2.5:1, 3:1, and 3.5:1 of gum Arabic to the crushed mahogany leaves by weight of the mahogany leaves were produced respectively. Twenty four (24) particleboards of sizes 200mm length, 50mm width, and 6mm thick were produced. The boards were cured for 28 days in an acclimatized room, after which tests on moisture content (MC), water absorption (WA) and thickness swelling (TS) were carried out in accordance with the ASTM D1037-93 procedures. Results of the tests indicated that the moisture content of the boards with mean and standard deviation values of 7.95% and 0.24% at the time of conducting the test was below the maximum of 10% specified by ANSI/A208.1-1999 standard. Particleboards produced using gum-Arabic-mahogany leaves ratio of 3.5:1 gave the best results in terms of the lowest mean values of water absorption (29.39%) and thickness swelling (23.8%) after four (4) hours of immersion in distilled water. The particleboards produced met the standard for general-purpose boards except for water absorption (WA) and thickness swelling (TS) characteristics which were above the maximum of 8% and 3% specified by ANSI/A208.1-1999.
Keywords: Particleboard, mahogany leaves, gum Arabic, water absorption, thickness swelling
| 9 |
Author(s):
N. D. Dangora, M.L. Attanda.
Page No : 64-73
|
Performance Evaluation for a Motorized Stationary Maize Dehusker Sheller Part 2: Model Validation
Abstract
The performance evaluation of a power operated stationary maize dehusker sheller at the Institute for Agricultural Research, IAR, Ahmadu Bello University, Zaria was conducted using QPM maize variety in order to validate an optimization mathematical model. The experiment was set in a factorial design involving four variables each at three levels; The layout was in a completely randomized block design (3x3x3x3= 81 treatments) and replicated three times. The analysis of the data was carried out using the SAS statistical package.. Duncan’s multiple range tests were used to compare the differences between significant means for variables. Best performance was obtained through appropriate ranking of the indices that need to be maximized (shelling, cleaning and output) and those that need to be minimized (grain damage and scatter loss).Best combination gave speed, feed rate, concave clearance and Moisture content of 950 rpm, 50 kg/min, 35 mm and 9 % respectively. The performance indices shelling efficiency, Output capacity, cleaning efficiency, grain damage and scatter loss obtained at this combination were 99.28 %, 844.69 kg/h, 97.07 %, 4.79 % and 16.24 %, respectively.
| 10 |
Author(s):
H. U. Abubakar, M. Ali , A.S. Abdulrahman.
Page No : 74-78
|
ENRICHMENT OF MAGAMI FERRUGINOUS MANGANESE DEPOSIT, ZAMFARA STATE, NORTH-WESTERN NIGERIA
Abstract
This work was carried out to enrich Magami ferruginous manganese deposit via sample collection, sample preparation, chemical and particle size analyses, and beneficiation tests. The collected materials from the site were prepared in the laboratory to obtain a representative sample. The elemental composition of the ore revelation of 13.1% Mn showed that the manganese deposit is by and large of low marketable grade in accordance with the International Manganese Institute classification (<30%Mn). The optimised beneficiation test conducted using 125 µm particles size with shaking table yielded an assay value of 38.71% Mn. Therefore, the concentrate is typically suitable for either manganese alloy or manganese pig-iron production by direct smelting.
| 11 |
Author(s):
M. Ali , S.A. Yaro, D.G. Thomas, N.S. Maina.
Page No : 79-83
|
DETERMINATION OF THE GRINDABILITY OF DARANNA-KA´OJE MANGANESE ORE, KEBBI STATE, NIGERIA
Abstract
The determination of the Daranna-Ka´oje manganese ore commenced with the systematic grab sampling of bulk material from 3 stationary stockpiles each of crushed run-of-mine (r-o-m) ore comprising of – 80 mm + 10 mm coarse and – 10 mm fine particles with a shovel at every 10 feet walk around their base. Later, the head sample of both reference (Itakpe iron ore) and test (Daranna-Ka´oje manganese ore) samples were generated by reducing their individual bulk samples to -5 mm + 2 mm size range particles with hammer mill and re-blended. Then 300 g each of the reference ore and the test ore were exposed to sieving through a nest of nine sieves comprising of 2000 µm, 1400 µm, 1000 µm, 710 µm, 500 µm, 355 µm, 250 µm, and 180 µm selected based on square root of two (√2). This was followed by grinding under the same parameters of mill size, grinding media, mill charge and tumbling time at 1425 rpm and final sieving. Using Gaudin Schuhmann relation for the determination of 80% feed and products of the reference and test ores; the grindability was determined from the generated results of the pulverised and ground sieve analyses by correlating the two ores’ work index. The ascertained grindability of 31.94 kWh/t implies that the grinding energy required per unit mass of the Daranna-Ka´oje manganese ore is more than twice the 15.86 kWh/t grinding energy required per the same unit mass of Itakpe iron ore under the same parameters. This is not out of place as the Daranna-Ka´oje manganese ore head sample is mostly made up of spessartine; which has hardness of 7 to 7.5. Moreover, manganese though similar with iron in some properties is harder as an element. Therefore, it is recommended that the design of comminution circuit should have more stages than that of Itakpe iron ore.
