Journal of Engineering in Agriculture and the Environment

INVESTIGATION OF THE EFFECTS OF THE DIFFERENT BIODIESELS’ BLENDS ON ENGINE PERFORMANCE

V.N. Kibiwot — 2024-07-16

Internal combustion (IC) compression ignition (CI) engines running on diesel, play a dominant role of today’s economies, particularly in the agriculture and transport sectors. However, because of diesel associated concerns greenhouse gases (GHG) emissions, coupled with depletion of its reserves together and fluctuations in prices, the biodiesel has gained popularity as a promising alternative fuel. Unfortunately, engines running on biodiesel are associated with decreased power output, poor fuel atomization and increased nitrogen oxides emissions. Biodiesels have been blended with diesel to improve on its properties, however, it has been a difficult to obtain the best blending level, since they are sourced from a variety of vegetable oils whose fuel parameters and interactions differ considerably, causing variation in their combustion processes. Thus, the research aimed to investigate the effects of biodiesels’ blends with diesel on engine performance parameters. Five biodiesels from waste vegetable oil, canola, sunflower, oleander, and coconut oil were characterized and blended with diesel at 10, 15, 20, 25 and 30% by volume. The blends were tested in a 3.5 kW CI engine at maximum speeds and loads. Experiments indicated the biodiesel blends lead to reduced lower heating value, increased density and kinematic viscosity compared to diesel. The blends resulted into increased fuel consumption and nitrogen oxides, while, reducing on brake thermal efficiency and carbon monoxide emissions

PERFORMANCE EVALUATION OF EXPERIMENTAL SOLAR EVAPORATIVE COOLING SYSTEMS

E. Mugwaneza — 2024-07-16

Evaporative cooling systems have many advantages over refrigeration systems, such as not necessarily requiring connection to the national grid, not using refrigerants that emit ozone-depleting substances into the environment, and can be constructed from locally available materials. However, little information on incorporating desiccant as an air preconditioning component to increase the performance of these coolers is available. In this regard, this study aimed to examine the efficacy of three cooling systems: an evaporative cooler with a silica gel desiccant component (desiccant cooler), an evaporative cooler without desiccant (desiccant-free cooler), and an evaporative charcoal cooler (charcoal cooler). Dry and wet bulb temperatures and relative humidity were recorded during the experiment and used to determine the cooling efficiencies of the systems; temperature drops; and humidity increases, which are used as performance indicators. Results demonstrate a significant (P<0.05) impact of the coolers on all analysed parameters. The desiccant cooler achieved the highest cooling efficiency at 87.2%, followed by the charcoal cooler at 79.3%, and the desiccant-free cooler at 67.2%. Temperature reduction was most pronounced in the desiccant cooler (3.7°C), followed by the charcoal cooler (3.2°C) and the desiccant-free cooler (2.8°C). Relative humidity levels increased by 30.7%, 23%, and 26.1% in the desiccant, desiccant-free, and charcoal coolers, respectively. Importantly, the evaporative cooler with desiccant operated without ozone-depleting refrigerants and utilized solar energy, offering an environmentally friendly solution. Its capacity to provide appropriate storage conditions for a wide range of fruits and vegetables makes it particularly beneficial for farmers lacking access to adequate cooling storage facilities, enabling them to preserve their produce effectively.

BIOPOTENTIAL PROPERTY OF MAGGOTS AS INOCULUM IN ANAEROBIC DIGESTION OF SUBSTRATES FOR BIOGAS PRODUCTION

T.F Oyewusi — 2024-07-16

A possible way of enhancing biogas yield from substrates is through the introduction of inoculum in a form of biomaterial with potential of increasing microbial population. Therefore, this research evaluated biopotential property of maggots as inoculum in anaerobic digestion of substrates for biogas production. The substrates used in the study are chicken droppings (CD) and swine dung (SD). The experiment was set up using biodigesters, water tanks with collectors. Cube-shaped plastic kegs of 25 L was adapted as biodigesters. The biodigesters were batch loaded and filled to 75% capacity, amounting to 18.5 L working volume with retention time of 5 weeks (35 days). During this retention time, the ambient and substrate temperatures were measured daily including the biogas yield while the pH was measured weekly. The result demonstrated that pH was within the range of 6.80-7.31, which is found to be within the standard of 6-8 pH level considered suitable for existence of anaerobic bacteria. Similarly, the mean temperature varied between 28.3-35.2ºC which is found to be within the range of 25-35 ºC reported to be suitable for the necessary anaerobic bacteria to survive. Furthermore, the total biogas yield for substrates treatment with maggots were higher compared with substrates treatment without maggots. This is an indication that the maggots have potential to enhance biogas yield when used as inoculum in production of biogas. Consequently, biogas production at higher yield can significantly reduce the overdependence on fossil fuels and other non-renewable forms of energy.

RICE PROCESSING TECHNIQUES AND EFFICIENCY DIFFERENTIALS IN NIGERIA

O.O Obisesan — 2024-07-16

The techniques of rice processing determine output optimization and level of efficiency of processors. This study was carried out to augment the dearth of knowledge of efficiency differentials of rice processing techniques in Nigeria. Analytical approaches include descriptive statistics and Data Envelopment Analysis-(DEA) which were used in analysing information from 410 rice processors in Nigeria. Index of processing techniques was traditional-techniques-(trad=<0.2-0.39); traditional and modern-Techniques-(trad-modern=0.40-0.79) and Purely Modern-Techniques-(purely-modern=>0.79). The results showed overall, 20.4%, 65.7% and 13.9% used Trad, Trad-modern and Purely-modern techniques of processing, respectively. Technical Efficiency (TE) was 0.4±0.3, 0.5±0.6 and 0.8±0.9 for trad, trad-modern and purely-modern techniques, respectively. Allocative Efficiency (AE) was 0.4, 0.6 and 0.9; while Economic Efficiency (EE) was 0.8, 0.3, 0.2. The TE differentials for trad-techniques relative to purely-modern and trad-modern techniques were 0.45 and 0.11, respectively. The AE differentials for trad-techniques relative to purely-modern techniques and trad-modern techniques was 0.01, while EE differentials for trad-techniques relative to the other two techniques was 0.6. The study shows rice processing in Nigeria exhibits a range of outcomes based on techniques used. While traditional methods persist due to their low cost, larger processors are increasingly adopting trad-modern and purely-modern techniques to improve efficiency and product quality. Addressing the efficiency differentials in rice processing requires a comprehensive approach, including investments in technology, infrastructure, and skill development to foster food security in Nigeria. These findings therefore challenge the notion that traditional-modern and purely modern techniques are less technically efficient than traditional techniques in rice processing.

SIMULATION OF SPATIO-TEMPORAL DYNAMICS OF STREAM FLOW TO CLIMATE VARIABILITY IN NJORO RIVER CATCHMENT, KENYA

E.O Amisi — 2024-07-16

Climate variability continues to alter hydrological regimes and the response of many catchments globally thus threatening water security. Njoro River Catchment has not been an exception. There is a steady recognition of climate variability and adverse influences like deterioration of ecosystems, surface, and groundwater sources. Therefore, the study focused on modelling the impact of climate variability on the spatial and temporal distribution of stream flow in the Njoro River Catchment, Kenya. Modelling of stream flow response to climate variability using SWAT was carried out based on USGS/NASA downloaded Digital Elevation Model, FAO soil data, Landsat (MSS 1-5) LULC of 1978, and meteorological data for the period (1978 - 2017). Simulation of spatial and temporal impacts of climate variability was then carried out. Based on the analysis, SUFI-2 algorithm results revealed that the most sensitive parameter in Njoro River Catchment is SCS curve number for antecedent moisture condition (II) (CN2), ranked according to the highest sensitivity tested at p < 0.05. The least sensitive parameter is maximum canopy storage (CANMX). Overall uncertainty analysis results showed a good performance value of P-factor (0.72) and R-factor (0.38), which indicated that SWAT reproduced the dynamics of the catchment hydrologic response relatively well. The values of R², NSE, and PBIAS for calibration and validation of monthly stream flow were 0.88 and 0.77, 0.86 and 0.74, and 5.51 % and -15.42 % respectively. From the spatio-temporal impacts of climate variability on hydrologic variables, actual evapotranspiration increased by about 5.6 %, 3 %, and 6.62 % in the 2^nd, 3^rd, and 4^th decades. Surface runoff decreased in the 2^nd decade by 34.56 % and increased by 4.55 % and 34.02 % in the 3^rd and 4^th decades. Annual water yield decreased in the 2^nd decade by 29.69 % and increased by 4.25 % and 60.18 % in the 3^rd and 4^th decades respectively. On average, stream flow reduced by 30.91 % in the 2^nd decade and increased by 5.47 % and 63.63 % in the 3^rd and 4^th decades respectively. These findings provide pertinent insights, which may perhaps enlighten decision-making in designing adaptable mitigation measures, catchment rehabilitation, and strategic initiatives for the integrated management of water resources.

EVALUATION OF MAINTENANCE EFFECTIVENESS AND HUMAN FACTORS: CASE STUDY OF A RESEARCH INSTITUTE

A.S Adebayo — 2024-07-16

Maintenance management is an integral part of any organization’s overall commercial process that develops administrative operational value. Thus, the maintenance function is of immense importance to ensure the safety and effective operation of a facility and equipment in compliance with a statutory obligation, to maximize equipment life, and to reduce the risk of failure. However, for maintenance success work planning, the perception of human factors, and the interrelation of workers and groups in any organisation must be understood. This in turn would determine the allocation of maintenance tasks to team members. This research focused on the evaluation of key performance indicators in relation to the maintenance effectiveness of selected equipment, in a research institution. The impact of human factors on the maintenance was also investigated. Key performance indicators such as Mean Time to Repair (MTTR), Mean Time Between Failure (MTBF), downtime, repair time, and availability were used to quantitatively evaluate the maintenance effectiveness of the equipment, while the systematic approach to empirical research was used to analyse the effect of human factors on maintenance practices. This study was carried out over a period of 6 months on a 4-tonne hydraulic lift, hydraulic hoist jack lift, tire changing machine, fault diagnostic machine, and computerized alignment gauge. Data collected from the maintenance unit was analysed. A total of 11.92 hours was recorded as the MTTR of the five machines. The machines had a high level of availability and a total downtime of 12.01 hours out of operational time of 2369.8 hours over a period of 6 months. The level of motivation and competence among maintenance personnel was assessed to be very good. This is expected to have contributed largely to the effective maintenance practices of workers in the unit. From this study, it can be deduced that the level of motivation and competence is high among maintenance personnel. In terms of productivity, effectiveness, teamwork, decision-making, execution, safety, and responsiveness, the human factor has been shown to have thrived well. This in turn, stimulated the corresponding increase in the availability of machines over the 6 months- of study.