ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY AND ENVIRONMENT

17-30

Authors: B Shettima, I Y Tanko, A Y Kuku, F D Adams

The sedimentology and paleoenvironment of the Deba-Fulani Member of the Pindiga Formation were investigated on the basis of their grain size distribution. Granulometric analysis has indicated that the samples are generally well to moderately sorted with skewness values ranging from negatively to positively skewed which may indicate influence of both marine and fluvial conditions. Bivariate plot relationships of standard deviation vs. mean, standard deviation vs. skewness, first percentile vs. mean also indicated both fluvial and marine setting for the middle part of the Pindiga Formation member. However, most of the bivariate plot showed dominance of fluvial environment. The probability curve plot shows a prevalence of three-sand population curves which are usually associated with wave processes indicating marine conditions for most part of the Deba-Fulani Member

40-48

Authors: I S Aji, M U Emmanuel, S A Abdulrahman, O F Franklyn

The development and construction of an electrically operated cassava peeling and slicing machine was described in this paper. The objective was to design, construct and test an electrically operated machine that will peel and slice cassava root into chips, to aid the processes of drying, pelletizing and storage. The methodology adopted includes; design, construction, calculation, specification, assembly of component parts and performance test. The machine was able to Peel and slice cassava to fairly similar sizes. Performance test reveals that 7 kg of cassava tuber was peeled and chipped in one minute, which shows that, the machine developed can significantly reduce the cost of labour and time wastage associated with traditional processing of cassava tubers into dried cassava pellets, and finished products, such as; garri, and cassava flour. The machine has a capacity of 6.72 kg/min, with peeling and chipping efficiency of 66.2% and 84.0% respectively. The flesh loss of the peeled tuber was 8.52%, while overall machine efficiency obtained as 82.4%. The machine is recommended for use by small scale industries and by cassava farmers in the rural areas. It has an overall cost of N46100 ($150). The machine can easily be operated by an individual and maintained, by using warm water to wash the component parts, and sharpening of the chipping disc when required.

58-64

Authors: J J Musa, I A Mustapha, I Y Yerima, I A Kuti, M E Abogunrin

Water is an integral issue needed to attain the desired targets but good quality water for irrigation purpose is gradually become scarce. The seasonal nature of rainfall can give rise to water stress at critical periods of growth. This research attempts to evaluate the irrigation application efficiency of Chanchaga irrigation scheme, Minna, Niger state. A hand auger was used to bore to a desired depth to remove samples of the moist soil. Samples of the moist soil removed was placed in a can, covered and taken to the laboratory. The specific gravity (apparent) of the soil particle and the depth of water applied were determined using volumetric method, water application efficiency is determined using Gravimetric Method of Soil Moisture Content (Pw) Determination. The moisture content of the field after irrigation water is applied falls between the ranges of 51.1% and 51.5%, with an average of 51.28%, in this case the average amount of water applied is about 4.68%, this shows a little increase in the moisture content of the soil in the field. It was concluded that the efficiency of water application obtained is adequate and a good result considering the available management practice in terms of system operation, monitoring and evaluation.

74-82

Authors: M M Odewole, M O Sunmonu, S K Oyeniyi, O Adeyinka-Ajiboye, Z O Ayodimeji

A study to optimize three mineral contents (magnesium, potassium and manganese) of dried osmo-pretreated green bell pepper was done using Response Surface Methodology (RSM). Five levels of osmotic solution concentration (A) (5% (w/w), 10% (w/w), 15% (w/w), 20% (w/w) and 25% (w/w)) of common salt and osmotic process durations (B) (60 min, 90 min, 120 min, 150 min and 180 min) were considered. After osmotic dehydration, all pre-treated and some control (unpre-treated) samples were dried at a constant temperature of 50˚C in a fabricated cabinet dryer. RSM under central composite design in Design Expert 8.0.3 computer software package was used to design the experiment, analyse data, optimize the process and present all results with 2-dimesional and 3-dimensional plots. From results obtained, optimized combinations were selected on the basis of their desirability values which were 0.931, 0.432 and 1.00 for magnesium, potassium and manganese respectively. From the desirability values on the response surface plots, the optimum (maximum) value of magnesium was found to be 29.18 mg/100g at osmotic process duration of 180 min and osmotic solution concentration of 25% (w/w); for potassium, the optimized value was 46.13 mg/100g at osmotic process duration of 60 min and osmotic solution concentration of 5% (w/w); while the optimized value for manganese was 10.96 mg/100g at osmotic process duration of 150 min and osmotic solution concentration of 15% (w/w). Dried pre-treated products had values closer to fresh samples than control (dried unpre-treated) samples for all the three mineral contents considered.

94-102

Authors: M O Sunmonu, Ogbonnaya Chukwu, Ron Haff

A Wind operated passive evaporative cooler was developed. Two cooling chambers were made with clay container (cylindrical and square shapes). These two containers were separately inserted inside bigger clay pot inter- spaced with clay soil of 7 cm (to form pot-in-pot and wall-in wall) with the outside structure wrapped with jute sack. The soil and the jute sacks were wetted with salt solution. Five blades were constructed inside the cooling chambers with aluminium material which were connected with a shaft to a vane located on a wooden cover outside the cooling chamber. The vanes (made of aluminium) were to be powered by the wind which in turn rotates the blades inside the cooling chamber. The total volume of 40500cm3 and storage capacity of 31500cm3 were recorded for the square structures while total volume of 31792.5cm3 and storage capacity of 24727.5cm3 were recorded for the cylindrical structures. During the test period, the average temperatures of 27.07oC, 27.09oC and 33.6oC were obtained for the pot-in-pot (cylindrical), wall-in-wall (square) and the ambient respectively. The average relative humidity of 92.27%, 91.99% and 69.41% were obtained for the pot-in-pot (cylindrical), wall-in-wall (square) and the ambient respectively. The average minimum and maximum wind speed recorded for the month of October was 2.5m/s and 2.6m/s respectively

110-121

Authors: Z A Mshelia, M S Abolarin, O K Abubakre, N A Ademoh

Natural moulding sands consist of refractory sand grains associated with clay right from their deposit locations. In Maiduguri, there are some sand casting activities taking place. However, there seems to be no single graded source of moulding sand that the practitioners can use for producing qualitative sand castings. Therefore, this study was carried out to characterise moulding sands from five selected deposits in Maiduguri for possible use in sand casting applications. Chemical compositions of sand samples were determined using XRF Analyser while American Foundrymen’s Society (AFS) standard laboratory tests were used to determine the physico-mechanical properties. The results of the characterisation revealed the following ranges of values; clay content from 21.8% to 47.2% corresponding to Pompomari and Gwange/Fori, grain fineness number from 50.94 AFS to 95.02 AFS corresponding to Pompomari and Gwange/Fori deposits.. Other physico-mechanical properties determined included; green and dry compressive strengths, permeability, loss on ignition and refractoriness. Results of chemical composition analysis show SiO2 having dominance in all the samples (90.10 % to 66.77 %) with trace elements of CaO, Fe2O3, Al2O3, MgO, TiO2, K2O, NaO2 also present within acceptable limits. The overall results show that all deposits have potential for use in sand casting applications for the casting of nonferrous metals and malleable and ductile iron. However, the clay content range given above is a major problem compared with the standards recommended by the American Foundry Society. This did not only limit their uses to low melting point alloys because of relatively lower refractoriness values but also possesses danger to their life expectancy. In conclusion, the use of the deposits characterised especially the Gwange/Fori deposit with clay content of 47.2 % should be used with caution because of the possibility of developing gas defects like blowholes and pinholes. All the other four deposits have been recommended for full exploitation for use in sand casting applications for casting of nonferrous metals as well as malleable and ductile irons. Finally, on the basis of the overall properties, the five deposits have rated in the following order of preferences; Dala Lawanti, Pompomari, Gwange/Fori, Gamboru and University of Maiduguri respectively.