Scholarly works in Agricultural and Environmental Engineering
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Item Moisture-dependent thermal properties of Cocoyam cormels(Faculty of Engineering, University of Maiduguri, Nigeria, 2019) Oyefeso, B. O.; Raji, A. O."Cocoyam (Xanthosoma sagittifolium) has served as a cheap carbohydrate source for many people in the developing countries with prospects in the production of animal feed, lager beer, and its starch as binding agent in drug formulation. Drying is an important unit operation in cocoyam processing and there appears to be lack of information on the thermal properties which are significant in designing heat treatment systems such as dryers for the cormels. This study therefore, investigated some thermal properties of X. sagittifolium cormels as affected by moisture content. Thermal properties namely thermal conductivity, diffusivity and specific heat of white- and pink-fleshed cocoyam cormels were investigated at moisture contents within the ranges of 130 to 395% and 85 to 200% (dry basis), respectively. The selected thermal properties of the cormels were determined with the aid of a thermal properties analyser which has a dual needle probe and uses transient line heat source method. Thermal conductivity, diffusivity and specific heat were within the ranges of 0.454 to 0.562 Wm-1K-1, 1.62×10-7 to 2.32×10-7 m2s-1, 1.836to 4.029 kJkg-1K-1, respectively for white-fleshed cocoyam and 0.489 to 0.601 Wm-1K-1, 1.79×10-7 to 2.65×10-7 m2s-1, 1.615 to 2.991 kJkg-1K-1, respectively for pink-fleshed cormels. Analysis of variance showed that there were significant differences between the measured properties at different moisture content levels. Regression models were established between the investigated thermal properties and moisture content.Item Estimating Mass and Volume of Nigerian Grown Sweet and Irish Potato Tubers using their Geometrical Attributes(Adeleke University, 2018) Oyefeso, B. O.; Raji, A. O.Sweet and Irish potato are tuber crops which have been domesticated and cultivated in different parts of the world including Nigeria. They are often prepared in various ways for food. A good knowledge of the physical properties of these tuber crops will enhance proper design of post-harvest processing machines and handling equipment with high level of performance. Also, functional relationships established between the various physical properties of these crops could assist in ensuring proper handling and more efficient and economical processing. This study was therefore, aimed at developing mathematical models for predicting the mass and volume of sweet and Irish potato tubers using some of their geometrical attributes. The research was conducted on fresh sweet and Irish potato tubers which were sorted into four fractions based on their individual mass. The physical characteristics measured include the mass, volume, linear dimensions (length, width and thickness) and the projected areas taken along the three mutually-perpendicular axes. The models were divided into three classifications namely: single and multiple variable regression models based on linear dimensions; single and multiple variable regression models based on the projected areas; single variable regression models based on mass or volume. Mass and volume models based on the projected areas and the volume were the best models for both crops. The highest coefficient of determination (R2) for sweet potato was obtained for mass model based on the projected area along the longitudinal plane (R2 = 0.981) while mass model expressed on the basis of the multiple regression of the three linear dimensions performed best (R2 = 0.968) for Irish potato. This study provided useful information that can help in the design of systems for handling and processing of sweet and Irish potato tubers.Item Effect of moisture content and loading orientation on elasticity of cocoyam cormel during transit and storage(International Commission of Agricultural and Biosystems Engineering (CIGR), 2017) Raji, A. O.; Oyefeso, B. O.Cocoyam (Xanthosoma sagittifolium) is one of the major staple food items in Nigeria. The crop is recently gaining attention and there is urgent need to intensify research efforts towards fully exploiting its promising potentials. Information on the elastic properties of the cocoyam cormels are necessary for understanding their behaviour under loading and in the design of equipment for proper handling of the cormels during processing and storage. This study investigated the effects of moisture content and orientation of loading on the elasticity of cocoyam cormels. White-fleshed and pink-fleshed varieties of the X. sagittifolium cormels were used for this study. The elastic properties of the cormels along the three mutually-perpendicular axes were determined. Deformation at rupture, modulus of elasticity (MOE), degree of elasticity (DOE) after first and third cycles along the longitudinal, cross-sectional and transversal directions ranged from 5.14 and 11.64 mm, 3.03 and 11.70 N mm-2, 0.51 and 0.73 mm, 0.45 and 0.70 mm, respectively. The degrees of elasticity of the cormels decreased with the increasing number of loading and unloading cycles thereby, limiting the stack height of cocoyam cormels in transit and storage to reduce mechanical damage and subsequent postharvest losses. The study provides the information which can serve as guidelines in ensuring proper handling of cocoyam cormels in transit and storage.Item Design, construction and performance evaluation of a rice destoner(CIGR, 2018) Aremu, A. K.; Oyefeso, B. O.; Ajao, T. O.; Ojo, K.; Egbunu, J. O.The market price of local rice in the market is significantly determined by its quality which is dependent on the level of cleaning and some other processing operations. Hence, the need to improve the quality of rice, increase production and reduce human labour has brought about the development of rice destoning machine. Therefore, this study aimed at designing, fabricating and evaluating the performance of a rice destoner. The design was based on the principle of material separation and was constructed from locally-available materials. The machine was powered by a 2hp electric motor and three vibrating screens of varying apertures were used for the upper, middle and lower screens. The machine had an average capacity of 130 kg/h. The performance of the machine was evaluated with 10 kg of Ofada rice at 11, 21 and 25% moisture content (dry basis) and 10 kg of Faro 55 rice at 14, 22 and 27% moisture content (dry basis). The results showed that separation efficiency decreased as the moisture content of rice decreased for both varieties. Cleaning of rice at low moisture content is recommended for optimum performance of the destoner.Item Design and Construction of a Lyophilizer system using locally available material(Nigerian Society of Engineers, 2017) Bello, R. O.; Raji, A. O.; Oyefeso, B. O.A lyophilizer system was designed and constructed with a galvanized metal sheet to reduce the cost and to make it available to local and poor food processors. It consists of 330.2 mm x 508 mm x 457.2 mm rectangular shaped chamber with the inner and outer layer reinforced with a hollow mild steel square pipe of 17 x 1.7 mm to prevent implosion of the lyophilizer during dehydration phase. The system was designed based on the specific heat capacity of Pears, Tomatoes and Carrot with values of 3.62 kJ/kg C, 3.98 kJ/kg C and 3.79 k/kg C respectively. The results showed that dry-bulb temperature of 28°C at initial stage and 1°C after drying while the dew point temperature of 20.8°C at initial stage and -6.1°C after drying were recorded. The result obtained also shows that the temperatures (dry-bulb and dew point) and relative humidity of the lyophilized product is lower as compared to the imported ones. A total of 6hours was used for freeze drying with 1/10 reduction in weight of the lyophililized product when weighed.Item Solar energy as a tool for poverty reduction and economic recovery in Nigeria - A Review(Nigerian Society of Engineers, 2017) Ilori, A. O.; Oyefeso, B. O.; Ilori, F. O.; Akintola, A.This paper examined the link between provision of solar energy and its impact on poverty in Nigeria. Solar energy in the tropical countries is the most common and abundant form of all renewable energies and it is essential as an alternative to the present source of electricity in Nigeria as well as for the improvement of the living standards of both rural and urban dwellers in the area of job creations, provision of social amenities as well as boosting human and economic productivity. It enhances living conditions by providing better lighting for homes, alternative source of power for cooking, heating and even pumping of water for various use in agricultural production. This study found that, essential aspects of human welfare (leading to long and productive life, good health, access to knowledge and education opportunities, potential to carn sufficient income to supply ample nutrition, shelter and other materials and even to boast the economy) may improve only if an alternative source of energy to combat the present epileptic state of power supply is made available. The study also found that, solar energy can have major favourable effects in remote rural areas and as a very dependable form of renewable energy technologies, offer a key prospect in areas where the grid cannot reach. This paper is a contribution to a process towards the use of solar energy to be one of the instruments to reduce poverty in Nigeria.Item Features extraction in agricultural products using computer image processing(Nigerian Society of Engineers, 2016) Raji, A. O.; Oyefeso, B. O.The study was based on the application of image processing and machine vision technology in the extraction of some features of interest in agricultural products. It involved the development of an algorithm that used some computer programs written in the FORmular TRANslation (FORTRAN 95) programming language to carry out tests on some input data images. The input data images were obtained by digitizing the original images of some Amaranthus vegetables, cowpea seedlings and some food samples on which some fungi were found to be growing as captured by a digital camera. The results of this study carried out on the images showed that the algorithm was able to extract both the boundary of the leaves and the crop position by discriminating between the crop and the uncovered soil surface as well as the growth of the fungi on the food samples. The extracted images as produced by the programs compared favourably well with the original images as captured by the digital camera. This visual comparison showed that the approach is very promising in developing automated sorting and quality inspection techniques which can be applied to some agricultural and food products.Item Efficacy of Diatomaceous Earth and Vitellariaparadoxa Seed Oil in Storage of Cowpea under Ventilated and Non-ventilated Conditions(Department of Agricultural and Environmental Engineering, University of Ibadan, Nigeria, 2019) Omobowale, M. O.; Akomolafe, O.P.Sto.age of cowpea is highly constrained by insect pest infestation and losses caused by the cowpea weevil (Callosobruchus maculatus, F.) are high. Several methods have been used over the years to protect cowpea grains in storage, but the use of synthetic insecticides is very dominant and this has led to problems, such as the killing of non-target species, user hazards, harmful food residues, and evolution of resistance to chemicals. A search for alternative insect pest control methods which are relatively less harmful to the user and cheaper has become essential. The effectiveness of Diatomaceous earth (DE) and Vitellaria paradoxa seed oil (VPSO) for cowpea storage in polypropylene and jute bags under ventilated and non-ventilated storeroom conditions were investigated over three months period. Crude DE was applied at a dose rate of 1 g/kg of cowpea and a diluted concentration (10% v/v) of VPSO of 400 mL was mixed with 8 kg of cowpea. Live insect count, dead insect count, and germination percentage were assessed weekly while proximate analysis was carried out before and after storage. Mean live insect count increased in the ventilated store-room from 0.67±0.34 to 36.13±19.51insects/kg after 1 month and 3 months of storage respectively for untreated cowpea. Insect population in treated samples increased from 0.38±0.26to 24.78±23.33, and from 0.17±0.30 to 10.75±5.27 for DE and VPSO treated samples, respectively. In the non-ventilated storeroom, insect population increased from 0.33±0.26 to 36.96±19.09 for untreated cowpea, 0.17±0.20 to 33.08±30.07 for DE and 0.21±5.63 to 8.17±11.30 for VPSO treated cowpea. Based on insect count, both treatments were very effective in controlling cowpea weevil in the first two months of storage, however their potency reduced by the third month. The potency of DE deteriorated faster compared to VPSO however, DE treated cowpea was most effective , or retaining seed germination in both ventilated and non-ventilated storerooms. Proximate analysis showed that cowpea treated with both treatments had similar nutrient composition after storage. Diatomaceous earth and Vitellaria paradoxa seed oil have potentials in their raw form for short term insect pest control in the storage of cowpea.Item Assessing efficacies of insect pest management methods for stored bagged maize preservation in storehouses located in Nigerian markes(Department of Zoology, University of Ibadan, Ibadan, Nigeria, 2019) Nwaubani, A.; Otitodun, G.O.; Ajao, S.K.; George P.O.; Ala, A.A.; Omobowale, M.O.; Ogwumike, J.C.; Grace I.E.; Ogundare, M.O.; Braimah, J.A.; Busari S.G.; Akhere E.O.; Kolayemi, O.R.; McNeill, S.G.; Ilelejif, K.E.Stored product insect pests cause significant losses in maize in sub-Saharan Africa (SSA). Control of these pests with conventional insecticides is fraught with health and environmental risks. Globally, several reduced-risk methods have been deployed as alternatives to conventional insecticides. In this study, conducted ir February—December 2016, efficacies of five treatments to control insects in bagged maize stored in Nigerian market storehouses were evaluated. Treatments included a botanical (Piper guineense), Bularafa diatomaceous earth (DE), permethrin powder (Rambo™), PICS (hermetic) bags and ZeroFly® bags. The study also had a negative control comprising untreated maize in polypropylene bags. Study locations were in three grain markets, namely Eleekara market in Oyo town and Arisekola market in Ladan, Oyo State, South West Nigeria, and Ago market in Ilorin, Kwara State, North Central Nigeria. Except in the case of PICS bags, each storehouse had six 100-kg bags for each storage method or trea.ment; these bags were sampled monthly. For PICS, each storehouse had 18 bags (~80 kg each) and six were destructively sampled every 4 months. Psocids (total 3,614) and S. zeamais (total 1,255) were the most abundant types of insects found during the study. However, among all treatments, PICS bags were the most effective at mitigating population growth of all species of stored product insects encountered, and the number of psocids and S. zeamais found in PICS bags during the entire study were 0 and 8, respectively. The order of effectiveness of the treatments were PICS > Permethrin > ZeroFly > DE > Botanical > control. Data showed PICS, Permethrin, ZeroFly, and DE when used according to manufacturer's instructions or label are effective and can be incorporated in integrated pest management of stored-product insects in maize storehouses. More research is required to explore how P. guineense can be made more efficaciouItem EFFECTS OF DIATOMACEOUS EARTH ON THE PROXIMATE COMPOSITION OF STORED COWPEA VARIETY (IT96D-610K)(Department of Zoology, University of Ibadan, Ibadan, Nigeria, 2019) Sunmonu M.O.A stuck' was carried out to determine the effect of a raw diatomaceous earth (DE) obtained fromBularafa community in Yobe State, Nigeria on the proximate composition of stored cowpea variety (IT96D-610K). Twelve small scale prototype silos made of two different structures (wooden and galvanised mild steel (GMS)) were constructed and used in the storage of the cowpea for a 4-month period. 7000g of cowpea at 9.88% moisture content admixed withdiatomaceous earth havingtwo different particle sizes(0.075mm and 0.090mm) and three different concentrations(0.1g, 0.05g and 0g of DE/100g of cowpea)in varying combinations were loaded into each silo. The sample admixed with zero concentration of diatomaceous earth served as the control in each of the wooden and galvanised steel structures respectively. Temperature, relative humidity and moisture content within the storage structures were monitored. Proximate compositionsuch as ash, crude protein, fat, crude fibre, carbohydrate alongside moisture content were also measured.Significant differences (p<0.05) was observed between the control sample and treated samples.The values of moisture content, ash content and crude fibre increased while crude protein, fat and carbohydrate decreased with increased storage period. At the last month of storage, wooden silo recorded a higher temperature value (28.88˚C) compared to the galvanised steel (GMS) silo which showed (22.30˚C). An increase in moisture content was observed in both silos with wooden silos showing a higher percentage rise in both control and treated samples. At the end of the fourth month the average moisture content, ash content, crude protein, fat, crude fibre and carbohydrate content of control and treated samples were(10.57% and 13.39%), (4.12% and 4.16%), (22.75% and 22.69%),(1.95% and 1.90%),(2.21% and 2.23%) and (57.75% and 55.63%) in the GMS and wooden silos respectively.Cowpea admixed with diatomaceous earth stored in GMS silo showed the best nutritional quality. Hence of all the storage materials, storage time, particle size and concentration of DE used galvanised mild steel (GMS), 0.075mm particle size and 0.05g of DE/100g of cowpea for the first four weeks of storage were seen to be the best. These proved to be the best method of storage for cowpea as the procedure retained its proximate composition. The increased crude fibre level in the treated samples is a major indicator for good health