Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
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Decline in agricultural activity around Lake Chad: Any prospect for restoration? A Review
Get PDFLake Chad that has been an economic hub for centuries has in the last few decades witnessed continued degradation threatening food security and livelihood of the population who depend on the lake for a living. The impact of depletion of the lake is being felt by an estimated 30 million people from the four riparian states, namely: Cameroon, Chad, Niger and Nigeria. This paper focuses on the causes of low agricultural activity around Lake Chad with particular emphasis on crop production. The paper also highlights the prospects for reviving agricultural activity through implementation of innovative soil management techniques. Analysis of the literature revealed that in addition to devastating effects of violent armed conflict on livelihood conditions in this region, frequent drought, dwindling rainfalls, degraded soils and sparser vegetation cover are among the factors responsible for the low agricultural activity in this region where a large proportion of the population relies on rainfed agriculture. The review revealed that organic farming practices that support biodiversity has the potential for besides improving soil health and reduce pest pressure, also improve crop yields and protect the environment. Furthermore, the use of biofertilizers to reduce the dependence on conventional inorganic fertilizers by farmers offers the means of mitigating the declining soil mineral nutrient reserves in this region. It is envisaged that restoring the lake to its near original state coupled with improving the productivity of the fragile soils will go a long way in addressing the challenges of food insecurity, a major factor stabilizing factor in the area.
 
Prediction of mass and volume of Tacca involucrata tubers using physical characteristics
Get PDFKnowledge of physical properties of crops is necessary for the development of processing machines. Relationships between the various physical properties of crops could also be useful in ensuring proper handling and more efficient design of processing machineries. This study was therefore, aimed at developing mathematical models for predicting the mass and volume of Tacca involucrata tubers using some physical characteristics of the crop. Physical characteristics of Tacca tubers at average moisture content of 73.3% (wet basis) namely axial dimensions, Arithmetic Mean Diameter (AMD), Geometric Mean Diameter (GMD), projected areas along the three mutually-perpendicular axes, criterion area (Ac), mass and volume were determined. Out of 240 samples used in the study, data from 120 samples were used for development of the prediction models while the remaining were used for validation of the developed models. Data analysis tool in Microsoft Excel (2013 version) was used to carry out regression analysis and develop the predictive models. Statistical parameters namely correlation coefficient, coefficient of determination, root mean square error and mean bias error were used to determine the goodness of fit of the predictive models. The mass and volume models were divided into three classifications namely: single and multiple variable regression models based on axial dimensions; single and multiple variable regression models based on the projected areas; single variable regression model based on volume (for mass prediction only). Average length, width, thickness, AMD and GMD of the tubers were 71.88, 57.22, 46.71, 58.60 and 57.57 mm respectively while average criterion area, longitudinal, cross-sectional and transversal projected areas were 2614.24, 2580.61, 2097.04 and 3165.07 mm2 respectively. Average mass and volume of the tubers were 129.30 g and 111.55 cm3 respectively. All the developed models performed well in predicting the mass and volume of Tacca tubers (R2 ≥ 0. 905) except for those based on the axial dimensions as single independent variables (R2 ≤ 0.890). The predicted mass and volume of Tacca tubers were not significantly different (p ≤ 0.05) from the experimentally observed values for all the classifications considered. Mass and volume modelling based on a single variable of any of the projected areas was the most convenient modelling for Tacca tubers since it involves the use of a single image capturing device and the whole measurement could therefore, be automated. The developed models would be useful for automated sorting and packaging of Tacca tubers
Green roofs: an alternative for the reduction of surface runoff in the city of Recife, PE
Get PDFConstant flooding during periods of intense rain, aggravated by the impermeabilization of the soil, is a recurrent problem in many Brazilian cities, such as Recife, located in the state of Pernambuco. An efficient alternative that can mitigate this problem is the use of compensatory techniques such as green roofs. Adding a plant layer on the roof of buildings can serve to reduce atmospheric pollution, contribute to an improvement in thermal sensation, and absorb rainwater, reducing the intensity of flooding. Therefore, the objective was to evaluate the reduction in the volume of water drained from the surface in cities, through the implementation of green roofs. To carry out this evaluation, a green roof and a Pluviometer prototype were installed to collect data on the volume of water precipitated, drained, and absorbed by the prototypes. The results show that the volume of water drained by the green roofs can vary significantly, from over 100% down to complete absorption of the precipitation, i.e., 0% of the water volume, as occurred on some days in May, which is the month that presented the lowest rainfall of the analyzed period. In addition, the analyses also show that as well as the prototypes, the real green roof significantly reduces the flow of water from precipitation. The mean reduction of the total volume in the study was 50%, however, at longer intervals without precipitation, this reduction reached 78%. These results show that the impact of the implementation of compensatory techniques such as green roofs significantly reduces runoff, especially in a city that is flooded. Therefore, this study can serve as an incentive for public and private institutions to adopt the compensatory techniques of urban drainage for future or existing constructions, due to the aggregated social benefits, although they are not currently mandatory for all new constructions. The authors proposed the implementation of compensatory techniques, such as green roofs, in urban centers with high percentages of impermeable soil
Systematic Layout Planning Approach in Process Layout Design for Processing Dehydrated Tomatoes
Get PDFThis study was conducted to determine an effective design for the processing of dehydrated tomatoes. The study proffer solutions to huge losses Nigeria encounters as a result of poor postharvest handling across the fruits and vegetables value chain. Despite the huge contributions of agriculture (vegetables) to Nigeria’s economic growth, postharvest losses stands at $9 million with 50% losses in fruits and vegetables as a result of their perishable nature. Systematic layout planning (SLP) approach was used in designing the process layout for dehydrated tomatoes. The design approach was used to serve as an improvement layout and also as a new design for processing of dehydrated tomato plant, with estimated 5% material losses during processing, average temperature for dehydration as 65oC, plant production time of 748.99 minutes/day, a throughput capacity of 10 tons/day is achievable. Additionally, the design was validated using computer simulation and the results obtained from the simulation analysis indicated that the method can be used to optimize process planning for several production processes of dehydrated fruit and vegetables
Influence of Extrusion Process Conditions on the Residence Time and Throughput of a Twin-Screw Extruder Using Full Factorial Experimental Design
Get PDFThe effect of extrusion condition on residence time and throughput rate of a twin-screw extruder was investigated using blends of sorghum groundnut and tiger nut in twin-screw extruder SLG65 Model. In this study, a three factor 3-level full factorial experimental design was adopted. The influence of extrusion cooking conditions on both the combine effect and the effect of independent variables were evaluated. The analysis of variance showed that both linear and quadratic were not significant, however, interaction significantly (P<0.05) affect both the residence time and the throughput rate of the extruded. The results revealed that the throughput rate ranged from (0.012-0.040 Kg/s). The highest value was recorded at 100°C barrel temperature, 50:30:20 feed composition for ratios of sorghum groundnut and tiger nut and 18% feed moisture content. While the residence time ranged from (47 - 66.0 S) the highest residence time was obtained at 110°C barrel temperature 50:30:20 ratios of sorghum groundnut and tiger nut and 26 % feed moisture content. The information provided about the residence time and throughput rate of a twin-screw extruder will be used in fabricating an extruder that will be used in producing similar extruded product. The result of the research could be used by intended processors of similar extruded product to explore the possibility of producing similar product by manipulating the processing variables in order to obtain a desired product.
 
Experimental Study on the Use of Banana and Pineapple Peel Waste as Biofertilizers, tested on Hibiscus Sabdariffa Plant: Promoting Sustainable Agriculture and Environmental Sanitation
Get PDFSynthetic fertilizers are combination of inorganic substances which causes long-term negative effects on the ecosystem. Indiscriminate agricultural waste disposal especially fruits peels waste when neglected and utilized unproperly can cause environmental pollution and spread of diseases. Fruit peels of banana and pineapple are highly rich in numerous bioactive compounds that can enhance plant growth. This study deals with managing banana and pineapple peel waste as organic fertilizer and compared their effects on the growth of Hibiscus sabdariffa. Three different formulations were prepared from sun dried and finely ground fruits peel of banana and pineapple extract, namely; Sample A containing 100g of banana peels powder, Sample B containing 100g of pineapple peels powder and Sample C containing 100g of a mixture of banana and pineapple peels powder. Four containers were used to collect 2kg of soil each, three of which were treated with the three formulations (Sample A, B and C). The fourth container was labeled sample D (Control). After 30 days of treatment, seeds of Roselle plant were sown in each container and plant growth parameters analyzed periodically. From the results, Sample A showed highest mean number of 3 days to germinate. After 21 days; Sample A had average large leaf area of 14cm2, then Sample B (12.92 cm2), Sample C (10.2 cm2) and Sample D having the smallest (9.6 cm2). After 120 days, average plant height recorded were; Sample A (78cm); Sample B (58), and Sample D (54cm), and sample C showed the lowest average plant height of 47cm. From this study, it was deduced that fruit peel powder formulations can enhance growth and yield of plants, thus limiting the use of chemical fertilizers and protecting the environment. It is recommended that fruits waste should be integrated into farms for enhanced agricultural productivity and clean environment
Effect of Compaction Pressure and Biomass Type (Rice Husk and Sawdust) on Some Physical and Combustion Properties of Briquettes
Get PDFIn this study, a simple manually operated briquetting machine suitable for use in rural community with no access to electricity supply was fabricated. A three (3) tone hydraulic jack and a pressure gauge were installed to allow for pressure variation. Some physical and combustion properties such as the compressed density, shatter index, hydrophobicity, combustion rate and ignition time of the produced briquettes were determined at the three (3) different compaction pressures of 420.4 kN/m2 , 525.5 kN/m2 and 630.6 kN/m2 . Rice husk (RH), sawdust (SD) and composite briquettes of rice husk and sawdust (RH/SD) were produced using cassava starch as a binder. The developed biomass briquetting machine had a minimum and maximum production capacities of 20 kg/hr and 30 kg/hr respectively. The results showed that the physical properties improved at an increasing compaction pressure. All the produced briquettes at different compaction pressures from the different biomass exhibited over 90% shatter index while the briquette produced from RH at compaction pressure of 525.5 kN/m2 had the highest combustion rate. The RH/SD briquette moulded at compaction pressure of 630.6 kN/m2 had the least combustion rate. The ignition time of the briquettes increased with increasing compaction pressure from 1.28 to 1.58. However, this study found that the RH biomass briquette exhibited a superior solid fuel quality property compared to the other briquette samples. Therefore, this study recommends the RH briquette as a sustainable source of solid biofue
Corrosion inhibition of Polyalthia longifolia leaves extract in 1m HCl solution on mild steel
Get PDFCorrosion is a very common phenomena in the manufacturing as well as chemical process industries. Corrosion has generated wide amount of interest worldwide because of its potential hazards to process equipment and machineries; which often leads to associated downtimes as well as adverse economic and safety consequences. The use of inhibitors is one of the most practical and efficient technique of protection against corrosion. In this work, the corrosion inhibition efficiency of polyalthia longifolia leaves extract in 1M HCl solution on mild steel surface was investigated using the standard gravimetric (weight loss) method. The results indicate that the extract could serve as a good green inhibitor. The inhibition efficiency increases with increase in the inhibitor concentrations. For the mild steel samples investigated in this work, about 70% inhibition efficiency was achieved with only 1.0 ml extract solution per 40 ml of 1.0 M HCl solution after five (5) days; and under same conditions, increasing the amount of extract by fivefold yielded only 10% increase in the inhibition efficiency for the same test period. The inhibition efficiency was also found to significantly increase with time of exposure for the first 48 hours of the experiment, but the increase was rather gradual at later times for all levels of extract concentration
Experimental investigation of the performance of a household refrigerator using plywood as radiation shield
Get PDFThis research work investigates the performance of domestic refrigerators. Test were carried out on two configurations of household refrigerators; a conventional refrigerator and a refrigerator that was modified by incorporating a radiation shield. In this work, plywood was used as thermal radiation shield placed between the back of the refrigerator and the condenser and compressor. Pressure gauges were welded to the evaporator inlet and condenser outlet. Thermocouples were attached to the compressor inlet and outlet, condenser outlet and evaporator inlet in order to obtain data from the test. The pressure and temperature data obtained was applied to evaluate the performance of the two systems. With further repeated tests, the coefficient of performance (COP) of the refrigeration systems were determined at normal ambient condition. The highest evaporator temperature obtained for the conventional refrigeration system (CRS) and modified refrigerators system (MRS) were -5oC and 0oC respectively. Interestingly, an efficiency improvement of about 10% was achieved for the MRS. The result shows a remarkable improvement in the COP of the MRS. Therefore, for a better performance, thermal radiation shield can be recommended to be incorporated in vapour compression refrigeration system
Mathematical prediction of nitrogen and phosphorus removal from piggery wastewater by horizontal sub-surface flow constructed wetland.
Get PDFMathematical equations were derived for estimation of nitrogen and phosphorus removal from piggery wastewater in horizontal subsurface flow constructed wetlands. The model inputs included wastewater inflow, retention, plant uptake and nutrient loss to the atmosphere by volatilization of nitrogen. Plant die off, precipitation and exchange with subsurface were considered negligible. The calibration and validation of the model was carried using different sets of experimental data generated from a pilot constructed wetland monitored over a period of seven months. The results show that the amount of nitrogen and phosphorus concentrations decreased exponentially within three days of retention in the wetland and, thereafter, the reduction appeared constant over higher retention time subject to the decay coefficient. There was high correlation between the simulated and observed parameters with R2 = 0.9537 for nitrogen and 0.9912 for phosphorus respectively. The low values of the mean bias error (ME) of 0.211 and 0.139, root mean square error (RMSE) of 0.32 and 0.18, and relative error of RE of 24 and 12%, demonstrated the ability of the model to predict nutrient removal accurately. The models efficiencies of 84 and 77% and index of agreements of 0.6527 and 0.8676 for nitrogen and phosphorus respectively, indicate an acceptable level of the models predictive capacities. The linear regression coefficients appear reasonable given that the system was a natural system located in the field, where uncontrolled influencing factors could weaken optimal performance. Because of challenges associated with Scaling-up this result. longer field studies are recommended. The models developed in this study considered the features of horizontal-subsurface-flow constructed-wetlands for removal of nitrogen and phosphorus from piggery wastewater. The high correlation between the developed models and the calibrated parameters showed that they are rational. The models can be used to simulate nitrogen and phosphorus removal in horizontal-subsurface-flow constructed-wetlands. The performance of these models meets the water quality discharge or reuse standards of Nigeria for wastewater discharge to land and surface water.