Investigation on thermal-hydraulic performance of outdoor heat exchanger in air sources heat pump

A plethora of findings exists on the decreasing heat transfer performance of ASHP under frosting condition. This study investigates, using field and laboratory experiments, the frosting behavior and heat transfer performance of fin-tube exchangers. Findings from our initial observation revealed the severity of frosting phenomenon during winter in hot summer and cold winter zone of China; for avoiding the lower COP, defrosting period of ASHP was not longer than 60 min. The results showed that the basic tube surface temperature decreases with running time and remains stable after 70 min, and an adverse pressure drop ensued. The findings, thereby suggests a 70 min defrosting period in ASHP. Comparing jH/fH and COP between exchangers revealed an improved performance of plain fin-tube exchanger over that of louver fin-tube exchanger in all the test conditions. Therefore, under frosting condition, plain fin-tube heat exchanger provides a superior thermal-hydraulic performance over louver fin-tube heat exchanger. Findings from this study will help designers and facility managers in taking a more informed decision when selecting heat exchanger types for ASHP

Experimental investigation on thermal comfort model between local thermal sensation and overall thermal sensation

To study the human local and overall thermal sensations, a series of experiments under various conditions were carried out in a climate control chamber. The adopted analysis method considered the effect of the weight coefficient of local average skin temperature and density of the cold receptors’ distribution in different local body areas. The results demonstrated that the thermal sensation of head, chest, back and hands is warmer than overall thermal sensation. The mean thermal sensation votes of those local areas were more densely distributed. In addition, the thermal sensation of arms, tight and calf was colder than the overall thermal sensation, which pronounced that thermal sensation votes were more dispersed. The thermal sensation of chest and back had a strong linear correlation with overall thermal sensation. Considering the actual scope of air-conditioning regulation, the human body was classified into three local parts: a) head, b) upper part of body and c) lower part of body. The prediction model of both the three-part thermal sensation and overall thermal sensation was developed. Weight coefficients were 0.21, 0.60 and 0.19 respectively. The model provides scientist basis for guiding the sage installation place of the personal ventilation system to achieve efficient energy use

Molecular identification and prevalence of Mycobacterium tuberculosis complex amongst people living with HIV in Osun state, Nigeria.

Human immunodeficiency virus (HIV) infection has created a special niche for Mycobacterium tuberculosis complex in humans as a result of the defect/reduction in cell mediated immunity. M. tuberculosis still responsible for most cases of death due to infectious diseases after HIV. In this study, prevalence of M. tuberculosis was determined in people living with HIV in Osun state of Nigeria with identification of culture positive isolates by polymerase chain reaction. A total of 160 samples were collected from people living with HIV with mean age of 36.8 years old of age (Median -34; age range 16 – 68; 95% confidence interval – 2.49) after seeking ethical approval from the Ministry of Health, Osun State. The result of the microscopy by ZN stain showed that 40 (25%) of the 160 samples were positive for acid fast bacilli while culture on Lowenstein-Jensen (LJ) medium revealed that 30 (18.75%) of the samples processed, grew organism that conformed to the characteristics of M. tuberculosis complex. Polymerase chain reaction for IS6110 was used to confirm the identity of the colonies on LJ slope as M. tuberculosis complex while the PCR for 260 bp of Rv1255c was used in identifying M. tuberculosis. M. tuberculosis represented 92% of the M. tuberculosis complex. The prevalence of M. tuberculosis among people living with HIV was found to be 15% after PCR identification. The effects of socio-demographic factors on the prevalence of TB were analysed. Occupation was found to be associated with the proportional distribution of TB in people living with HIV (X2 = 14.85; p < 0.05). The study concluded that PCR should be integrated into the schema for identification of tuberculosis in reference laboratories in developing countries.Key words: Molecular identification, Polymerase chain reaction, Mycobacterium tuberculosis complex; Mycobacterium tuberculosis, Prevalence, HIV, Nigeri

Assessment of Yield and Nutritional Qualities of Local and Improved Maize Varieties Cultivated in Wukari and Environement of the Nigerian Guinea Savanna Agro-Ecology

Two varieties of maize (quality protein and local) were cultivated and evaluated for nutritional qualities, agronomic traits performance and yield during the 2016 and 2017 cropping seasons at the Teaching and Research Farm of the Federal University Wukari. Wukari is situated on latitude 70 52’17.000N and longitude 90 46’40.300E. It falls within the guinea savannah of North-eastern Nigeria with the annual rainfall of 1058mm-1300mm and relative humidity dropping to about 15%, alongside an annual temperature of 280C and 300C. Its characteristic alfisol soil is clay enriched, with subsoil that has relatively high native fertility. Pollination was controlled in order to conserve the genetic purity of the two varieties. Data obtained were subjected to analysis of variance (at p ≤ 0.05), using the 23rd edition of SPSS. Statistical analysis revealed significant differences among the varieties for grain yield, nutritional content, days to tasseling, days to silking, plant height at six weeks after planting, number of seed rows, number of nodes, seed length, hundred seed weight (g) and ear heights. Oba super 2 showed superiority (31.75g) over the local variety for seed yield (100 seed weight). Crude protein concentration in the two varieties varied significantly, with the local maize variety recording a higher value (7.21%)

HEALTH COMMUNICATION AND AWARENESS OF ALUMINIUM-WASTE DISPOSAL EFFECTS AMONG OGUN STATE HOUSING CORPORATION RESIDENTS

This paper surveyed residents of the Ogun State Housing Corporation who have resorted to collecting aluminium waste as a cheap alternative to assuage the deplorable state of road networks in the estate. 200 copies of the questionnaire were randomly distributed to residents of the Housing Estate. The resolve of the survey was to determine the level of awareness (about the health and environmental implications) of aluminium waste, as well as decipher their level of involvement in the collection, use and contact with these waste materials. In cases of awareness about these health implications; the medium through which they gained such awareness was further queried. It was recommended upon findings that harnessing the participation of all stakeholders (the Residents association, the Industrial wing and the Ogun State government) would bring stability to the growing demand for these materials within the Estate. Similarly, coordinating educative and informative campaigns through the existing meeting platforms in the Estate would expedite enhanced consciousness and eventual cessation of the possibilities of contact and inhalation of aluminium waste in the Housing Estate

Model free kinetics analysis of Imperata cylindrica (Lalang)

This study is the first attempt at investigating the solid state decomposition and the devolatilization kinetics of Imperata cylindrica (lalang) grass termed the “farmer’s nightmare weed” as a potential solid biofuel of the future. Biomass conversion technologies such as pyrolysis and gasification can be utilized for future green energy needs. However an important step in the efficient utilization and process optimizing of biomass conversion processes is understanding the thermal decomposition kinetics of the feedstock. Consequently, thermogravimetric analysis (TGA) of Imperata cylindrica was carried out in the temperature range of 30-1000 °C at four heating rates of 5, 10, 15, and 20 K min-1 using Nitrogen at a flow rate of 20 L min-1 as purge gas. Using the TGA results, the kinetic parameters activation energy (Ea) and pre-exponential frequency factor (ko) of the grass were estimated via the model free or isoconversional methods of Kissinger and Starink. The results obtained for Kissinger model were 151.36 kJ mol-1 and 5.83 × 109 min-1 for activation energy and pre-exponential frequency factor respectively. However, Starink model activation energy and pre-exponential frequency factor were a function of conversion (α) with average values of 159.93 kJ mol-1 and 6.33 × 1022 min-1 respectively

Case Report:False-negative HIV-1 polymerase chain reaction in a 15-month-old boy with HIV-1 subtype C infection

Polymerase chain reaction (PCR) testing is the gold standard for determining the HIV status in children &lt;18 months of age. However, when clinical manifestations are not consistent with laboratory results, additional investigation is required. We report a 15-month-old HIV-exposed boy referred to our hospital after he had been admitted several times for infectious diseases. A rapid antibody test on the child was positive, while routine diagnostic HIV PCRs using the Roche COBAS Ampliprep/COBAS TaqMan HIV Qual Test were negative at 6 weeks, 6 months, 7 months and 15 months. In addition, the same PCR test performed on the HIV-infected mother was also negative. Alternative PCR and viral load assays using different primer sets detected HIV RNA or proviral DNA in both child and mother. Gag sequences from the child and his mother classified both infections as HIV-1 subtype C, with very rare mutations that may have resulted in PCR assay primer/probe mismatch. Consequently, the child was commenced on antiretroviral therapy and made a remarkable recovery. These findings indicate that more reliable PCR assays capable of detecting a wide range of HIV subtypes are desirable to circumvent the clinical problems created by false-negative PCR results

Personal Data Collection and Usage for Mobile Marketing Customer Awareness and Perception

Marketers have often relied on data to better understand the preferences of the customer base. While the traditional methods were engaged in the retrieval of data, the mobile devices connected to the internet introduced an influx of data on a real time called big data. Based on this advancement, marketers with the technical capacity are able to identify customer needs accurately and identify sway in trends. Although this strategy seems beneficial to the marketers, the naïve nature of the customers to the collection and usage of personal online information for mobile marketing remains a crucial poser. Hence, this study through survey sought to identify the awareness level and perception of 700 undergraduates in three higher institutions in Lagos, Nigeria. Results show that all the respondents had connected mobile devices, received advertising messages on their devices and were active shoppers online. Furthermore, the females were more aware of the collection and usage of personal data, hence, they embraced the collection based on relevance of advertising messages and strict use for mobile marketing. This study therefore recommended marketers’ collection and usage of customers’ personal data to be based on strict use for mobile marketing and assurance of relevance of advertising messages

Telecom Outcasts? Exploring Women Airtime Hawking and Mobile Telephony in Southwest Nigeria

Women are considered vital and indispensable to the economic growth and sustainable development of any nation, but their subordinate position in the workplace in Africa is a concern. This study investigates the motivations behind airtime hawking by Nigerian women who operate at the bottom end of their country’s mobile telephony business and are confined to the informal segment of the industry. A total of 625 respondents attended to questionnaire items about the factors that predisposed them to sell airtime on the streets. Results show they hawked to avoid being disturbed by the local revenue collectors and for quick and steady patronage, albeit small profits. The least contributory is that airtime hawking does not require a selling technique. These indicators are useful for industry captains, policymakers, and multilateral organisations interested in improving the conditions of women and their absorption into the mainstream economy

CFD study on the effects of different temperatures and feed velocities for CO2, CH4, and C2H4 adsorption using 5A molecular sieve

The removal of carbon dioxide (CO2) from natural gas is a practical measure in dealing with problems such as CO2 emissions into the atmosphere and reducing the cost of gas processing operations. Adsorption is a promising technology currently used, specifically pressure swing adsorption (PSA) method. In this paper, the adsorption column packed with 5A molecular sieve was simulated using COMSOL Multiphysics software for the separation of CO2 from natural gas components, which are methane (CH4) and ethylene (C2FLi). The effects of different temperatures on adsorption time were investigated and the optimum adsorption time was determined by the purity of CH4 and C2H4 at the column outlet. This study will be beneficial for optimising the design and process configuration of PSA