Coal combustion models: a review

Abstract : Computational Fluid Dynamics has been used for optimisation of industrial applications with some level of success. The modest accuracy provided by some of the combustion models in use has left some room for research and improvement. Coal is presented as a fuel with complex chemical properties due to its fossil fuel nature. The devolatilization process of coal is investigated with special attention to the best models that can handle heavy and light volatiles found in coal. The heterogenous char combustion is also presented paying attention to the nature of the char particle during the combustion process. The other processes such as drying, homogenous volatile combustion, radiation models, particle tracking models and turbulent models are investigated in a general manner as they rarely vary with the type of fuel being investigated. A summary of the industrial applications that have successfully utilised the CFD models for optimisation of coal combustion are presented thus helping in drawing the final conclusion

HOST PLANTS OF THE COTTON MEALYBUG, PHENACOCCUS SOLENOPSIS TINSLEY (HOMOPTERA: PSEUDOCOCCIDAE) IN THREE SELECTED TOWNS OF NIGERIA, AND ITS INFESTATION PATTERN

Reconnaissance surveys were carried out for field infestation of Phenacoccus solenopsis Tinsley from 2006 to 2010 in seventy five (75) vegetable gardens located in three (3) towns– Ogbomoso, Abeokuta and Ibadan in Nigeria. No cotton mealybug infestation was observed in Abeokuta and Ibadan, but twenty four (24) plants in 16 different families were observed as its hosts in Ogbomoso area. Of the 24 species, weeds constituted 45.8%, vegetables 29.1%, herbs 12.5%, cereals 4.2%, fruit trees 4.2% and pulse 4.2% each. Infestations started on the abasial leaf surface and advanced to the mid-ribs, petiole, young and succulent stems and buds. Corchorus olitorius and Amaranthus hybridus were the most susceptible of the trialled plant species with heavy root infestation in addition to that of the leaf. On heavily infested plants, certain ants were found together with P. solenopsis; on cowpea however, Aphis craccivora and the ants formed a complex with the mealybug on the flower buds. Of the three towns surveyed, P. solenopsis could be said to be restricted to backyard gardens around Ogbomoso at the moment. However, a nation-wide survey is very necessary now to determine the current status of the mealybug in Nigeria.Â

IMPACTS OF COAGULANTS ON QUALITY OF SOFT CHEESE PRODUCED FROM COW-SOY MILK BLENDS

Production of cheese at household level involved the use of different locally produced coagulants which include alum, Sodom apple and fermented maize liquor. Their effects on quality of cheese made from blends of cow-soy milk are sparse. This work investigated effect of coagulants on soft cheese produced from cow soy blends. Soft cheese samples were produced from cow-soy milk blends (90:10%). The cheese was coagulated using three locally available coagulants {juice of Sodom apple (Calotropis procera), aqueous solution of Potassium alum and fermented maize liquor}. Samples were analysed for yield, pH, proximate and mineral contents. Microbial analysis and sensory attributes were also determined. The yield obtained ranged from 38.7 to 39.0%. Highest yield was obtained from Sodom apple coagulated cheese sample. Cheese produced using fermented maize liquor had the highest pH (6.07) while Sodom apple and alum coagulated cheese had the pH values of 6.83 and 6.97, respectively.  The moisture contents of the produced cow-soy cheese ranged from 70.4 to 73.57%. The protein content of the cheese samples coagulated with alum had the highest (12.97%) in all the samples. There was no fiber in all the cheese samples produced. Calcium contents obtained from the three samples ranged between 171.67 and 185.00 mg/100 g. The iron content of cheese coagulated with fermented maize liquor (3.63 mg) was significantly (p < 0.05) higher than that of alum coagulated (3.23 mg/100 g) and Sodom apple coagulated cheese (3.33 mg/100 g). Higher microbial load was recorded in cheese samples coagulated with FML. The sensory attributes of the cheese samples varied with different coagulants. This indicates that the type of coagulant used in cheese-making has effect on the yield, pH some nutritional and sensory attributes of cheese

Awareness and knowledge of the sustainable development goals in a University Community in Southwestern Nigeria

Background: The Sustainable Development Goals (SDGs) is a globally  accepted developmental agenda, and it is expected that everyone everywhere in the world would be aware, knowledgeable and be willing to contribute to its  attainment. This study aims to assess the level of awareness, knowledge of, and attitudes towards the SDGs among members of a university community. Methods: A cross-sectional survey was conducted on 450 students and staff of Osun State University, Southwestern Nigeria, selected from three of its six  multi-campuses via multi-stage sampling. Data were collected by means of  semi-structured questionnaire. Data were analysed using SPSS version 20.0. Results: The mean age for the respondents was 26(10.2) years. Only 43% of the respondents were aware of the SDGs and only 4.2% had good knowledge of the SDGs. However, 56.3% had positive attitude towards it. More respondents with good knowledge of the SDGs were either acadenic staff or those have been  enlightened via personal study of the SDGs or through other means. Similarly having a positive attitude was associated with being an academic staff/ high level of education as well as belonging to the middle age group. (p<0.05). Conclusion: The awareness of and attitudes towards the SDGs was just fair. However, the level of knowledge was abysmally low, and this has serious  negative implications for SDGs attainment. Pertinent individual and  population-level methods of enlightening people about the SDGs must be put in place in educational settings; curricular changes are imperative. Keywords: Attitudes, Awareness, Knowledge, MDGs, SDGs, University

Investigation of household refrigerator system with varied capillary tube length

Abstract : In this paper, the performance of R600a was investigated in a household refrigerator originally designed to work with R134a using varied capillary tube length (1.0, 1.15, 1.30 and 1.45 m). The refrigerator was instrumented with four thermocouples at the inlet and outlet of the major components. Also, two pressure gauges were connected to the compressor to measure the suction and discharge of the compressor. The experimental results were used to evaluate the performance of the system. The results showed that at optimal capillary tube length the COP and cooling capacity of R600a in the system increased with 45% and 4.2% respectively and the power consumption reduced with 25% using 1.30 m varied capillary tube length compared to R134a. Conclusively, R600a can serve as a retrofit in the household refrigerator systems originally designed to work with R134a refrigerant

ASSESSMENT OF CHEMICAL AND ANTINUTRITIONAL PROPERTIES OF BREAKFAST MEAL PREPARED FROM BLENDS OF BANANA AND AFRICAN YAM BEAN

Banana (Musa sapientus) and African yam bean (Sphenostylis stenocarpa) are nutritional food sources that are valuable industrially even in consideration for a balanced nutrition. This research work evaluates the production of breakfast meal from blends of Banana and African yam bean (AYB). Banana and AYB were mixed in the ratio 90:10, 80:20, 70:30 and 100:0 (control) for the production of breakfast meal. Crude protein, ash, crude fiber, fat and carbohydrate content of mixtures were determined using the AOAC methods. Vitamins, minerals and anti-nutrient composition of the breakfast meal were determined using standard methods and data were analyzed using Analysis of Variance (ANOVA). Sensory attributes were determined using 9-point hedonic scale by forty panelists. The results of the proximate analysis showed that protein ranged from 5.41-11.26%, fat content (1.97-4.56%), carbohydrate (72.71-79.89%), fiber (0.39-0.57%), ash (3.23-3.97%) and moisture content (7.86-8.20%). Oxalate (8.73-4.38%) decreased with increase in AYB inclusion. Tannin values ranged from 17.09-26.73% and phytate ranged from 11.59-46.77%. The sensory evaluation by the panelists shows that the product was widely accepted. Samples 100:0 and 90:10 were mostly preferred in terms of colour, texture, taste, crispiness, sweetness, flavour, appearance and general acceptability. Hence, the fortification of banana flakes with AYB can be encouraged as a breakfast meal

Professional development in teaching and learning for early career academic geographers: Contexts, practices and tensions

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 16th May 2011, available online: doi: 10.1080/03098265.2011.563380This paper provides a review of the practices and tensions informing approaches to professional development for early career academic geographers who are teaching in higher education. We offer examples from Britain, Canada, Nigeria and the USA. The tensions include: institutional and departmental cultures; models that offer generic and discipline-specific approaches; the credibility of alternative settings for professional development in teaching and learning; the valuing of professional development and of teaching in academic systems of reward and recognition; and the challenges of balancing professional and personal life. We summarize concepts of good practice and suggest opportunities for future research

Quality attributes and phytochemical properties of fresh juice produced from selected mango varieties

Mango (Mangifera indica L.) is a seasonal and highly perishable yet nutritious fruit with different varieties. Further, processing of the fruit will extend the shelf life and increase the potentials of exploiting the underutilized varieties. This paper investigated the suitability of four Nigerian mango varieties (Lippen, Kent, Palmer and Saigon) for fresh juice production and also evaluated the quality attributes of the stored juice samples. Well ripen, firm mango fruits were processed into juice, packed and stored at room temperature (28±2°C). Selected chemical (titratable acidity, pH, brix, ascorbic acid) and phytochemical (saponin, phytates and tannins) properties were determined. Sensory attributes of fresh juice were evaluated. All determinations were done in triplicates and data were subjected to analysis of variance using SPSS. Samples were tested in 4-day intervals till 24 days post juice production. Juice obtained from Kent variety had the least titratable acidity (7.83±0.2 mg/100 g), pH (4.41 ±0.2 mg/100 g), brix (11.83 ±0.2 mg/100 g) while Lippen had highest values of titratable acidity (10.23 ±0.2 mg/100 g), pH (5.27±0.0) and brix (14.73 ±0.1 mg/100 g) after 24 days of storage. Ascorbic acid content was highest (12.10 ±0.0 mg/100 ml) in Lippen juice while least value (9.40 ±0.3 mg/100 ml) was observed in Saigon juice. Ascorbic acid contents of juices decreased as storage period progressed. Saponin and phytate were present in all samples and decreased with increased storage time while tannin was constant from day 16 to 24. Saigon juice was the most preferred of all the tested juice samples in terms of overall acceptability when evaluated for sensory properties

Effect of Temperatures, Air Velocity and Flow Rate on Quality Attributes of Dried Cassava Chips

Abstract In this work, cassava chips were dried in a tunnel dryer at temperature 60 0 C, 70 0 C and 80 0 C using velocity 3.0m/s, 3.2m/s and 3.4m/s and load capacity of 7.5kg/m 2 , 10.0kg/m 2 and 12.50kg/m 2 as the drying variables. From the drying of experiments, data were generated to open up insights for the study and understanding of the physical parameters of the dryer as they affected the chips. The physical parameters studied in the dryer were air velocity, tray load capacity and air temperature. The effect of these drying parameters were evaluated on the quality attributes of the chips such as moisture content, bulk density, water absorption capacity, swelling capacity, residual cyanide content and colour. The results showed that drying temperatures and load rates had great effect on the quality attributes of the chips

Interface strength of glass fibers in polypropylene: Dependence on the cooling rate and the degree of crystallinity

status: publishe