Exergy, Performance And Environmental Impact Analysis Of Compression Refrigeration Systems

Major concern in refrigeration hinges largely on energy conservation, environmental safety and efficient cooling system. The concept of quality of useful energy which invariably leads to energy conservation is naturally related to exergy. This study therefore experimentally conducts exergy, performance and environmental impact analysis of compression refrigeration systems using R134a, R410a and R407c, refrigerants. The experiment was performed using a modified exiting R134a refrigerating system. The refrigerator was built with Scroll compressor, 48m3 evaporator space, 1m throttle length and 0.2mm array of rods in the condensing unit coupled with thermocouple K attached at the various components and a digital 10^-3 accuracy weighing scale for charging refrigerant in the required grams. The results show that for 100 grams charge of the refrigerants, the exergetic efficiency, coefficient of performance (COP) and the degree of environmentally friendliness of each of the refrigerants are of order R410a > R407c,> R134a and for 80 grams charge of the refrigerants, the order of performance is R410a > R134a> R407c. While for 60 grams charge of the refrigerants, the exergetic efficiency, coefficient of performance and the degree of environmentally friendliness of each of the refrigerants are of order R407c> R410a > R134a, that of 40 grams charge of the refrigerants is of order R134a> R407c> R410a. The study therefore established that irrespective of the grams charge values of the investigated refrigerants used, R410a is the best, closely followed by R134a and lastly R407c

Evaluation of nutritional and functional properties of plantain (Musa paradisiaca L.) and tigernut (Cyperus esculentus L.) flour blends for food formulations

Open Access Journal; Published online: 28 Sept 2017Some individuals are intolerant to gluten of wheat and other cereals like oats, rye and barley used for food formulations and this intolerance seriously impairs intestinal absorption. There is need to develop alternative gluten-free flours for baking and confectioneries. This research therefore aimed at determining the chemical and functional properties of plantain–tiger nut composite flour to be able to explore its potentials in food formulation. The flours made from matured plantains and tiger nuts were blended at the ratio of 100:0, 70:30, 60:40, 50:50, 40:60, 30:70 and 0:100 to make different plantain–tiger nuts flours and these were analysed using standard methods. The results revealed that protein ranged from 4.55 to 6.78/100 g, fat (2.25–32.75/100 g), crude fibre (3.50–6.13/100 g), bulk density (0.81–0.92 g/cm3), swelling power (38.38–2.37/g), Mg (30.65–49.08 mg/100 g), P (3.65–120.65 mg/100 g), K (71.62–212.08 mg/100 g), Vitamin C (3.18–5.30 mg/100 g) and Vitamin A (1.71–51.31 μg/100 g). There were significant differences (p < 0.05) in the pasting profile of the plantain–tiger nut flour blends and in functional properties of composite flour except for bulk density. Addition of tiger nut flour improved the proximate, mineral and vitamin composition of the composite flour and the study concluded that inclusion of tiger nut flour is a good protein, fat, mineral and vitamin supplement for plantain flour

Quality evaluation of snack produced from black pepper (Piper nigrum L.), plantain (Musa paradisiaca L.) and tigernut (Cyperus esculentus L.) flour blends

Open Access Journal; just-acceptedChinchin has been identified to be one the favoured food items and a much-relished pastry which has been eaten as dessert or snack. This study aimed at evaluating the nutritional quality and organoleptic properties of black-pepper enriched Chinchin produced from plantain-tigernuts composite flour. Matured plantains (Musa paradisiaca), tigernuts (Cyperus esculentus) and black pepper were processed into flour. Chinchin was processed from different blends of plantain and tigernuts composite flour at the ratio of 100:0, 70:30, 60:40, 50:50, 40:60, 30:70, and 0:100 for plantain and tigernuts respectively. Five percent (5%) black pepper spice was added to each of the samples for Chinchin production. Proximate, mineral and vitamin compositions were determined using standard methods. The results of proximate composition of the different snack samples showed significant differences (P<0.05) with values ranging from 6.50-10.00%, 4.45-6.75%, 2.25-32.75, 1.33-2.00%, 3.50-6.13% and 46.07-78.48% for moisture, protein, fat, ash, crude fibre and carbohydrate contents respectively. There was significant difference (p < 0.05) in the minerals and vitamins contents, and organoleptic properties of the black pepper chinchin samples. In conclusion, chinchin of improved and acceptable nutritional and organoleptic properties could be obtained using plantain-tigernuts composite flour and black pepper spice for improved nutrition. This product could add to range of snacks available for those with special dietary needs

Circular Economy strategies of social enterprises in Lagos: a case study approach

The circular economy (CE) framework has the potential to play a vital role in facilitating a different kind of development in low and middle-income country (LMIC) contexts, due to its promise of improving resource productivity, creating jobs and minimizing environmental degradation from human and economic activities. This thesis addresses how the CE is conceptualized and how its principles can be established in an African context, such as Lagos Nigeria, focusing on social enterprises (SEs) as the object of study, thereby responding to calls that links SEs to sustainable development and that explores the socio-institutional or behavioral changes necessary for achieving circularity. It explores the overarching research question: How are social enterprises establishing a circular economy in Lagos? Following a case study strategy, nine SEs operating in the waste sector in Lagos were studied by triangulating the data obtained from in-depth interviews, documents, and archival records. This study demonstrates practical CE implementation examples as findings from the data analysis shows how SEs are organizing differently to collect, aggregate and upcycle waste materials, while also engaging in clean-up and advocacy programs to retrieve more recyclables from the environment. It highlights volume-drivers, core-transformers, and clean-advocates as examples of new circular models that can be advanced and adapted to make a living from waste in low-income and resource scarce environments. By demonstrating how commercial, social, and environmental objectives are being pursued, this thesis contributes to the understanding of hybrid organizing in a LMIC context and shows how the CE embraces the social dimension of sustainable development beyond only job creation. Additionally, this thesis shows how institutional logics and institutional work can be combined to study the CE, contributing to calls on the concept’s underexplored institutional perspectives. It highlights institutional work in an African context by showing that establishing the CE in Lagos requires disrupting the logic of waste mostly seen as a thing to be thrown away. By changing existing and legitimating new waste practices, while maintaining a formal organizational structure, SEs are disrupting the logic of waste and establishing the CE in Lagos. The effect of their purposive activities on informal waste pickers in Lagos were discussed, while also drawing out policy and practice implications of the findings for advancing CE initiatives in Lagos and Nigeria, as well as in other LMICs

Investigation of ethanol productivity of cassava crop as a sustainable source of biofuel in tropical countries

The ethanol productivity of cassava crop was investigated in a laboratory experiment by correlating volumes and masses of ethanol produced to the masses of samples used. Cassava tubers (variety TMS 30555) were peeled, cut and washed. 5, 15, 25 and 35 kg samples of the tubers were weighed in three replicates, soaked in water for a period of a day, after which each sample was dried, crushed and the mash mixed with 500 ml of N-hexane (C6H14). This crushed mash was then allowed to ferment for a period of 8 days and afterwards pressed on a 0.6 mm aperture size and sieved to yield the alcohol contained in it. The alcohol was heated at 79°C for 10 h at intervals of 2 h followed by an h cooling. Ethanol yield was at average volumes of 0.31, 0.96, 1.61 and 2.21 litres, respectively, for the selected masses of cassava samples. Quantitative relationships were obtained to relate the masses of cassava used to the masses and volumes of ethanol produced. These were used to relate known production values of cassava from tropical countries to ethanol that can be potentially produced. The ethanol had boiling point of 78.5°C and relative density of 0.791. The dried mash was found to contain 61.8 calories of food energy per 100 g. This study found that a total of 6.77 million tonnes or 1338.77 million gallons of ethanol are available from total cassava production from tropical countries. The production and use of ethanol from cassava crop is recommended in the cassava-growing tropical countries of the world.Keywords: Cassava, ethanol, fermentationAfrican Journal of Biotechnology Vol. 9(35), pp. 5643-5650, 30 August, 201

IMPACT OF TEACHERS’ INCENTIVE ON PERFORMANCE OF PHYSICAL AND HEALTH EDUCATION TEACHERS

Poor academic achievement of pupils in Nigerian primary schools together with its attendant problems has been worrisome to stakeholders in education system such that several factors like teachers’ incentives and other perennial problems has been pointed to as the cause of its occurrence. This study investigates the impact of teachers’ incentive on teachers’ performance in primary schools in Ogun State. A descriptive survey research design and simple random sampling technique was used to select 100 teachers from both private and public schools for the study. A self-developed questionnaire was used to collect data for the study while collected data analyzed using ANOVA statistics. The findings showed that (i) there is significant difference in teachers’ condition of service and teachers performance in primary school (F (1,98) = 10.245, P &lt; 0.05), (ii) there is significant difference between teachers’ fringe benefit and teachers performance (F (1,98) = 8.133, P &lt; 0.05), (iii) the relationship between teachers’ incentive and teachers’ performance in primary school is positive and significant (r = 0.146* at p &lt; 0.05). It was suggested that government should improve welfare packages, condition of service and other benefits of teachers.  Article visualizations

Impact of Decadence of Education on the National Security and Sustainable Governance in Nigeria

This paper investigates the causes for the decadence and continuous decline of education and its impact on the national security and sustainable governance in Nigeria. The paper with the use of descriptive design along with the secondary data collection, analyses the various negative ways the continuous and incessant closure of the public educational institutions in Nigeria can have on the national security and sustainable democratic governance in Nigeria state. The finding of this paper is that the government has not done enough to arrest the situation, and that the country is therefore heading toward total disintegration. The paper also believes that the inadequate budgeting for the educational sector has contributed greatly to the inefficiency of Nigeria’s educational institutions at all levels. The paper therefore recommends that the governments should revisit their budget provisions by voting more funds for this important sector and as a matter of urgency, the government at the central levels should speedily resolve the ongoing strike of public university staff, while those closed institutions since February 2022 be opened within a shortest period in order to return the students back to their schools

Experimental performance of LPG refrigerant charges with varied concentration of TiO2 nano-lubricants in a domestic refrigerator

This article present an experimental investigation of varied mass charges of Liquefied Petroleum Gas (40 g, 50 g, 60 g and 70 g) enhanced with varied TiO2 nanoparticle/mineral oil concentrations (0.2 g/L, 0.4 g/L and 0.6 g/L nanolubricants) in a R134a compressor of a domestic refrigerator. Performance tests investigated at steady state included: pull down time, power consumption, compressor power input, cooling capacity and coefficient of performance (COP). Analysis was based on temperature and pressure readings obtained from appropriate gauges attached to the test rig. Refrigerant property characteristics were obtained using Ref-Prop NIST 9.0 software. Results obtained showed almost equal evaporator air temperatures and reduction in power consumption for all tested nano-lubricant concentrations except at 70 g charge of LPG using 0.6 g/L nano-lubricant. Furthermore, the lowest compressor power input was found to be 21 W and obtained using 70 g of LPG with either of 0.2 g/L or 0.4 g/L nano-lubricants. At 70 g of LPG using 0.6 g/L concentration of nano-lubricant, highest cooling capacity index of 65 W was obtained while the highest COP of 2.8 was obtained with 40 g charge of LPG using 0.4 g/L concentration of nanolubricant. In conclusion, LPG-TiO2 nano-lubricant mixture works safely and efficiently in domestic refrigerators without modification of capillary tube length, but requires adequate optimization

Characterization of the Germania Spraberry unit from analog studies and cased-hole neutron log data

The need for characterization of the Germania unit has emerged as a first step in the review, understanding and enhancement of the production practices applicable within the unit and the trend area in general. Petrophysical characterization of the Germania Spraberry units requires a unique approach for a number of reasons ?? limited core data, lack of modern log data and absence of directed studies within the unit. In the absence of the afore mentioned resources, an approach that will rely heavily on previous petrophysical work carried out in the neighboring ET O??Daniel unit (6.2 miles away), and normalization of the old log data prior to conventional interpretation techniques will be used. A log-based rock model has been able to guide successfully the prediction of pay and non-pay intervals within the ET O??Daniel unit, and will be useful if found applicable within the Germania unit. A novel multiple regression technique utilizing non-parametric transformations to achieve better correlations in predicting a dependent variable (permeability) from multiple independent variables (rock type, shale volume and porosity) will also be investigated in this study. A log data base includes digitized formats of gamma ray, cased hole neutron, limited resistivity and neutron/density/sonic porosity logs over a considerable wide area