Analysis of Heat Transfer using Radiation in Circular Finned-Tube Heat Exchanger
Transferring heat using conduction and convection requires the presence of a temperature gradient in some form of matter ,while the heat transfer by thermal radiation requires no matter. It is extremely important process, and from physical sense it is perhaps the most interesting form of the heat transfer modes. It is relevant to many industrial heating, cooling, and drying processes, as well as to energy conversion methods that involves fossil fuel combustion and solar radiation. In this paper, our objective is studying the radiation in Circular Finned-tube heat exchanger. Finned-tube heat exchangers are predominantly used in space conditioning systems, as well as other applications requiring heat exchange between two fluids. One important widespread use is in cooling applications. The results show that the heat transfer in the mode of the radiation is just about 2% compared with forced convection , but when there is natural convection in the system the term of radiation is considerable.
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Assessment of Heavy Metal Contamination of the Lower Pra River, Ghana
In this study, surface water and sediments were collected from twenty-four (24) different sites in four different locations along the longitudinal transect of the Lower Pra river and evaluated for their quality using several multivariate statistical methods including Principal Component Analysis and pollution index model. Environmental parameters such as heavy metals, water nutrients and physicochemical parameters were determined in the dry and wet periods. The PCA indicated that heavy metals Fe,-Mn,-Ni and-Zn were from predominantly natural sources, whilst Hg,-Cu and-Pb were from anthropogenic sources. Fe-Mn-Zn-Ni had an association with TSS whilst Hg-Se-Pb had an association with TDS.
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Biodegradation of Hydrocarbon by Micro-organisms Isolated from Crude Oil Contaminated Soil in Niger Delta Area of Nigeria
Soil that was artificially polluted with Escravos light crude oil was degraded with hydrocarbon degrading micro-organisms isolated from crude oil contaminated soil in Niger Delta area. The micro-organisms isolated and applied included Enterobacter aerogenes, Serratia marcescens and Proteus myxofaciens immobilized in coconut fibre as a carrier. The results of the laboratory analysis showed that the immobilized micro-organisms bacteria had good self-life with micro-organisms load of 5.43 x 108 cfu/ml and 2.52 x 1019 cfu/ml on the first and 28 days respectively. The results gotten from immobilized micro-organisms system are good for the biodegradation of hydrocarbons. At the expiration of 28 days of applying the immobilized micro-organisms system in the laboratory scale degrading of Escravos light crude oil, the remaining concentration of total hydrocarbon decreased to 14.36 % for one of the samples compared to the remaining concentration of total hydrocarbon of 85.31 % in the control sample. Therefore, the immobilized micro-organisms system using coconut fibre as a carrier can serve as an effective and fast biodegradation tool for cleaning up petroleum hydrocarbon polluted soil at low cost.
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Changing language teaching through language testing: a washback study
The notion of "washback" is common in the language teaching and testing literature, and tests are held to be powerful determiners of what happens in classrooms (Alderson and Wall, 1993). "Washback" refers to the influence of language testing on teaching and learning (Cheng, Watanabe, & Curtis, 2004). Milanovic and Weir's book Changing Language Teaching Through Language Testing: A Washback Study offers insights into the concept that a test can be used to encourage innovation in the classroom.
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Characterization and antimicrobial susceptibility patterns of clinical salmonella isolates from Nandi County of rift valley, Kenya
Salmonellosis, a water and foodborne infection is a major cause of high morbidity and mortality in Sub-Saharan Africa. Its prevalence and mortality has been associated with antibiotic resistance related strains that calls for specific strain identification. Data on prevalence and antimicrobial susceptibility patterns of Salmonella in Nandi County of Rift Valley is scarce despite the scourging effect of the disease. 200 stool samples were collected from patients treated for diarrhoea at Kapsabet District hospital between (February – November, 2011). 84%(n=168) were positive for various bacteria isolates as determined by standard microbiological culture techniques. 29%(n=48) were Salmonella. The distribution was; S.typhimurium 56%(n=27),S. enteritidis 29%(n=14),S.paratyphi C 6%(n=3), S. paratyphi A 4%(n=2), S.gallinarum 2%(n=1),S. dublin 2%(n=1). Isolates were confirmed by API 20E biochemical system in addition to invA gene sequencing. All Salmonella isolates were resistant to ampicillin, (19%) were resistant to sulfamethoxazole .Resistance to tetracycline, streptomycin and chloramphenicol was (6%).All ampicillin resistant isolates possessed blaTEM gene while sulfamethoxazole resistant isolates had sul2 gene both genes are associated with class1 integrons. The findings indicated a low antimicrobial resistance in relation to other regions within the country. This situation should be encouraged. Additional safety measures should include training in personal hygiene, sanitation and ensuring water quality.
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Constraints in mentha (mentha arvensis l.) production in Pratapgarh District of U. P.
The present study was conducted in three villages in three development blocks in Pratapgarh distrct U.P. to documents the constraints experienced by the mentha growers. The research results were grouped into technical, financial and social constraints. The study revealed that mentha cultivation are quite primitive and traditional, resulting low yield and poor quality of produce. It is evident from the study that lack of improved techniques of mentha cultivation, availability of quality seed, farm machinery, distillation plant, Procurement agency, market and related information, organized farmers are major constraints faced by the farmers. The cultivation of mentha becomes more difficult when growers are not getting credit facilities and are paying more rent for land.
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Corporate Governance in India: Principles and Practices
In the age of competitive Globalization and dynamic world, business enterprises need to focus on innovative practices which will help in maximizing stake and shareholders wealth. The fundamental concern of corporate governance is to ensure that the firm’s directors and mangers act ethically in the interests of he firm and its shareholders and that the mangers are held accountable to capital providers for the use of assets. The concept of corporate governance can be taken as a parallel to the quality practices under the ISO standard. It also involves entry of non-executive directors into the board, and making the members more positive and dynamic in their activities. All business information must be made available to them, and system controls are activated to ensure authenticity, timeliness and effectiveness of information. Globalization and Liberalization have taken the Indian corporate world towards the international field. This, not only is there a need to establish viable and acceptable corporate governance, but it should also conform to international standards. The basic principles of corporate of corporate governance are based on ethical parameters such as complete transparency, integrity and accountability. The present paper addresses the issues of corporate performance, transparency, strategies, executive functions, compensation and accountability, auditors and several related issues.
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Culturally responsive teaching: a missing element of teacher education in Pakistan
Culturally responsive teaching is usually advocated for making teaching effective and to let students from diverse background feel comfortable. The study is aimed to explore to what extent in-service teachers observe culturally responsive teaching in their professional practices, to what extent in-service teacher training opportunities are available regarding culturally responsive teaching and to what extent existing teacher education programs address these aspects. The study ravels that, in Pakistan, the element of culturally responsive teaching is missing both from the curriculum of teacher education programs and education systems as a whole. Teachers encounter cultural diversity in their classrooms but lack of knowledge about students’ cultures and culturally responsive teaching cause hindrances to teach children from diverse back ground more appropriately. Non-availability of teacher training opportunities regarding culturally responsive teaching further undermines their professional responsibilities. This study has made some recommendations to prepare prospective teachers ready to teach in culturally responsive classrooms.
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Determination of heat flow anomaly in Agbor, delta state
Heat flow values were obtained from four boreholes located at Agbor, Delta State, Nigeria. The values obtained from the four wells, A, B, C and D was respectively 75, 68, 60 and 56mWm-2. However, the average value of 64.75mWm-2 is very close to the estimated value of 65mWm-2 from the semi-empirical law of heat flow versus lithospheric age. The platinum resistance thermometer and the thermistor were used for the measurement of borehole temperature. From the measured temperature distribution, the temperature gradient was computed. The formation heat flow was obtained by multiplying the gradient by the mean thermal conductivity of the rocks. The interpretation of high and low values of heat flow in wells A and D respectively were explained. However anomalous high heat flow values have been observed in well A. The result reveals that a hot plate mobility of heat carrier through some structural boundary and chemical reactions of some organic matters are some specific causes of high heat flow anomaly in the area of the research.
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Divalent Nickel (Ni2+) Removal Using Thermally Derived and Regenerated Activated Cocos nucifera Shells
Thermo-chemically cracked cocos nucifera shells were converted into useful adsorbent using chemical activation method. Regeneration of the spent carbon was carried out via thermal regeneration method. The re-derived filter was used in the adsorption of nickel (Ni) from a simulated Ni2+ solution. Qualitative characterization was carried out using the Fourier Transformed Infra Red Spectrophotometer while Atomic Adsorption Spectrophotometer was used to analyze the equilibrium phase Ni2+ concentration. Comparative study of the derived and regenerated activated carbons was carried out using kinetic adsorption studies approach. From the experimental runs, it was evident that derived cocos nucifera shells activated Carbon provided slightly higher removal efficiency values than the vice for Nickel uptake. Investigations with applicability test supported the pseudo second order kinetics as best model in explaining the sorption rate (k2 = 0.744) as against the proposed linear and first order kinetics. Generally, reuse of spent coconut shell carbon and its investigated film diffusion transport mode in removal of Ni2+ is critical a study with a worthwhile adoption in remediation study.
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