A Manually Operated Cassava Grating Machine

The design and development of a manually operated cassava grating machine prototype are presented. The prototype grater is shown to be easy to operate at 30 - 45 rpm to give a product whose quality is as good as that from motorized graters at a throughput of 125 - 185 kg/h. The prototype grater is a powerful alternative to the sedentary drudgery and pain-inflicting process involved in the traditional grating method

A Kitchen Appliance for Shelling Egusi

"Egusi" is the common Nigerian name for the food seeds considered to be of the Citrullus Sp. and inclusively known as "melon" seeds. On the basis of experience gained in the design and construction of a spinning disc "melon" seed shelling machine for large scale factory applications, a kitchen appliance of shelling egusi was designed. The prototype was constructed as an accessory to a kitchen blender. The performance test showed that the appliance performed satisfactorily with a shelling effectiveness of nearly 100% and minimum percentage breakage of about 8% at a capacity of about 10 kg/h

Design of a Continuous-Process Gari Frying Machine

A prototype gari frying machine, designed to faithfully simulate the traditional manual frying technique, was fabricated and tested. The prototype consists of a 1.7m long semi-circular frying trough of 57 cm diameter, and a gang of sixteen spring-loaded spatula-like paddles evenly spaced within the trough. Electric-motor driven and designed to oscillate through about 1800 at 40 reversals per minute, the paddles press the automatically/continuously metered gari mash against the hot trough when moving in one direction and then scrape the mash off, stir it and move it forward when moving in the opposite direction. The prototype produces a continuous flow of fried gari at 66 kg/hr. The prototype has a provision for manual operation when it produces 20 to 45 kg of gari per hour

Development of a Ridge Profile Weeder

The prototype weeder described in this paper consists of a ground-driven rotating horizontal short shaft which is connected by universal joints to two gangs of rotary hoe weeders. With the short shaft nearly at the bottom of a furrow between two ridges, the gangs of weeders lie on the sides of the two ridges. The universal joints make it possible to angle the weeder gangs with respect to the horizontal shaft to make the gangs conform to the profiles of the sides of the ridges facing the common furrow. The operator walks in the furrow and simply pushes the weedier along to weed one side each of two ridges. Thus the weeder can handle any crop planted on ridges, irrespective of the height of the plants. The shares on the gangs of the rotary hoe weeders are independently adjustable to facilitate reaching the surface of any ridge. Field tests show that this weeder is very effective in controlling young weeds where only light earthling up is required

Tractability Conditions for Disc Ploughing on a Loamy Sand Soil in the Ilorin Agro-Ecological Zone

For agricultural field operations such as tillage and planting, an agricultural soil is considered tractable if it can develop adequate shear resistance to minimize tyre slip and soil damage and can produce required soil tilth without undue soil pulverization or the formation of large clods. Furthermore, the soil must be devoid of physical obstructions like stones, stumps, ant-hills, etc and be of a light vegetative cover. Tractability conditions for disc ploughing on a loamy sand soil based on soil moisture have been determined for Ilorin agro-ecological zone, which fall within the Guinea Savannah zone of Nigeria. This was achieved by carrying out disc ploughing on an experimental plot at thirteen different soil moisture levels ranging from 8.90 to 91.74% of field capacity. The tyre slip and wheel sinkage measured at each soil moisture level, were used to judge whether the soil was tractable or not. Soil is adjudged tractable if the observed tyre slip is either 15% or less. The corresponding soil moisture range was selected as the soil moisture condition at which the soil is tractable. It was found that the loamy sand soil of Ilorin agro- ecological zone was tractable between soil moisture levels of 8.90 and 60.08% of field capacity. Results showed that differences in soil moisture distribution along the slope of the land had no significant (P< 0.05) effect on the towing force and the drawbar pull of the tractor. However, differences in soil moisture levels had significant effect on them. Furthermore, data such as towing force, drawbar pull, soil cone index and tyre slip generated and analyzed using regression analysis, were used to establish empirical trafficability prediction equations; which are useful in studies of soil-machine interactions

Performance evaluation of Magnus screw press (Model MS-100) for palm kernel oil extraction

The screw (expeller) press is extensively used for commercial extraction of palm kernel oil (PKO) from oil-palm kernels. In this work, Magnus (Nig.)screw press (Model MS-100,) locally fabricated at Nsukka, Nigeria was evaluated for throughput capacity, feed rate, press cake oil content, oil expelling efficiency (OEE), percentage un-pressed grits output, percentage sludge output, and specific energy consumption. One-factor-at-a-time (OFAT), completely randomized designed (CRD) experimental approach with 4 factor levels and 2 replications was used to determine the effect of kernel moisture contents (KMC), kernel heating temperatures (KHTs), and kernel heating durations (KHDs) on the (OEE) of the screw press. Analysis of variance (ANOVA) technique was used to analyze the results. In its best operating settings, the MS-100 screw press has a throughput capacity of 91.7 kg-products/h at an average feed rate of 101.7 kg-kernels/h, press cake oil content of 13.6% (w/w); percentage actual oil yield of 33.6% (w/w); percentage cake output of 38% (w/w); percentage un-pressed kernel grits output of 14.2% (w/w); percentage sludge output of 3.6% (w/w); OEE of 73%; and specific energy consumption of 0.44 kWh/kg-kernels. The screw press is adjudged suitable for palm kernel oil extraction based on its OEE. The ANOVA of the results show that the best kernel factors for highest OEE include KMC of 5% w.b.; KHT of 50 - 130o C; and KHDs of 5 - 10 min. The 14.2% un-pressed kernel grits output, however, is a problem of Magnus Screw Press that needed to be reduced or eliminated through design modifications.Keywords: Palm kernel oil, screw press, oil extraction, Magnus screw pres

Characterization and Modelling of the mixing in the Athabasca River downstream of a pulp mill

Methods for predicting the transverse mixing coefficient, Ez in rivers based solely upon estimates or measurements of the channel geometry, channel slope and flow parameters are not completely reliable. Therefore, it is generally necessary to perform field tracer tests in order to determine Ez for a particular river reach at a given stage and flow. Characterizations of the transverse mixing in the Athabasca River downstream of a pulp mill located near Boyle, Alberta are described herein. The characterization of the mixing is based upon analysis of four tracer tests conducted on the river (three continuous input tests and one slug test). The tracer tests were conducted on different dates and cover a range of flow conditions (October 1994, 270 m3/s; February 1995, 84 m3/s, and August 1997, 960 m3/s and 876 m3/s). The February test was conducted under ice-covered conditions. Beak Consultants Ltd. conducted the October 1994 and February 1995 tests. The tracer input for each field test consisted of injection of Rhodamine WT fluorescent dye at the mill outfall location. In the continuous input tests, the tracer was injected into the mill effluent stream at a constant rate and entered the river via the effluent diffuser structure. The diffuser is 52 m long, oriented perpendicular to the flow, and located close to the left bank of the river. In the slug input, test a known mass of tracer was instantaneously dumped directly into the river at approximately the mid-point along the length of the diffuser. For each test the dye plume was sampled across transects oriented perpendicular to the river flow at a number of downstream locations stretching over a 32-km reach of the river. Hydrographic surveys were conducted at each sampled transect and at several other transects to determine channel geometry and flow parameters. The hydrographic survey information and the tracer input conditions were required for numerical modelling of the mixing in the river reach. The implementation of the two-dimensional river mixing modelling procedure used in the present study was written by Putz (1996), based upon the descriptions given by Beltaos and Arora (1988). The numerical model utilizes a streamtube approach and a numerical procedure employing an advection optimized grid to limit numerical errors. The model is capable of simulating continuous input and unsteady input conditions. The modelling package includes two preprocessing programs for generating the calculation grid based upon channel characteristics, a two-dimensional, transient mass input mixing program, and a post-processing program for output of data at selected locations. The transverse mixing coefficient was determined for each field test using the model fit of predicted tracer concentrations compared to the concentration of the samples collected in the field. The mixing simulations provide a very good representation of the measured concentration distributions. The four field verification studies demonstrate that the Advection Optimized Grid method can be applied to two-dimensional, steady and unsteady source mixing problems in natural streams satisfactorily. Nondimensionalized transverse mixing coefficients determined from the modelling procedure are compared to the range of values reported in other locations. These comparisons show that the values of ß which characterize the transverse mixing in the reach of the Athabasca River studied fall well within the range of reported ß values from other studies. Reach-averaged dimensionless mixing coefficient, ß, is fairly consistent (in the range of 0.34 to 0.48) for the range of flow conditions represented by the four tests. The overall weighted average of ß for the different ranges of flow was found to be 0.41. The results demonstrate that the dimensionless mixing coefficient measured at one flow condition may be used with the appropriate flow parameters to estimate mixing for other flow conditions for the same reach. The results of the modelling procedure are also used to assess the variation in mixing with discharge and due to the presence of an ice cover

Confronting the challenges of agricultural mechanization in Nigeria in the next decade: some notes, some options

"The man with the hoe" still remains an apt description of the Nigerian farmer today. In spite of decades of immense expenditures and investments into agriculture, in terms of money men and materials, by national and international governments and agencies, the average Nigerian farmer remains an indigent serf, regarded by today's youths as a dreadful anachronism. The Nigerian agricultural industry, populated as it is by aged and ageing peasants, has progressively developed into a world of drudgery for losers, shunned and despised by Nigerian youths. To change this ugly/unsavoury image of Nigerian agriculture, it has now become imperative to adopt an appropriate level of engine-power agricultural mechanization technology (EPAMT), necessary and sufficient to modernize, energize and revitalize the industry. This paper opines that the most viable option to achieve the objective is a mechanization strategy which can create the conducive environment for the emergence of small-to-medium-scale (SMS) market-orientated, youthful farmers, who will voluntarily choose to go into agriculture as a respectable and profitable business. This canvassed SMS farmer-oriented mechanization strategy is justified in this paper with objective analyses of information and data collected through surveys, interviews and a requisite review of relevant literature

Sembradora automática de dos surcos para estacas de Yuca : desarrollo, diseño y construcción del prototipo

Reimpreso del Journal of Agricultural Engineering Research, p. 1978, v. 23, p. 109-116Due to copyright restrictions, this item cannot be share