90 research outputs found
A BOUND TESTING ANALYSIS OF EXCHANGE RATE PASS- THROUGH TO AGGREGATE IMPORT PRICES IN NIGERIA: 1980-2006
This paper examines the extent of pass-through of exchange rate into import prices for Nigeria between 1980 and 2006 using the recently developed UECM-Bounds test proposed by Pesaran et al. (2001). Empirical evidence reveals that world export prices has a dominant effect compared to exchange rate in explaining changes in Nigeria¡¯s import prices in the short and long run. The major implication for our study therefore is that exogenous factors such as world export prices appeared to be more important determinants of domestic import prices than a country¡¯s exchange rate policies.Aggregate Import Price, World Export Price, Bound Testing, Nigeria
Solar and geothermal energy for low-carbon space heating and energy independence.
In developed countries, space heating is highly dependent on fossil fuels consumption. Also, the non-renewable fuels combustion emits CO2 which is claimed to impact the most on greenhouse effect. The utilization of Renewable Energy Sources (RES) for space heating, instead of fossil fuels, has been found to be feasible for systems’ greater energy independence and reduction in CO2 emissions. Solar Assisted Ground Source Heat Pump (SAGSHP) systems are a promising technology which can be used to accomplish the above framed target.
A mathematic model of a SAGSHP system was built and a parametric analysis for Birmingham which is a city located in the UK’s West Midlands was conducted. Two scenarios based on two different dwellings were investigated, the one was a house recently erected and the other was a refurbished house. As regards the new house, simulation results showed that the utilized energy for space heating and Domestic Hot Water (DHW) can vary from 33% up to 73% RES dependent and, at the same time, electricity generation can be 2.21 times higher than the system’s demand. As regards the energy renovated dwelling, the RES contribution to the delivered heat was found to be between the 33% and 63%, while the electricity generation did not result in any surplus energy from the consumed. Finally, by making use of SAGSHP system instead of a natural Gas boiler, the reduction of CO2 emissions was found to be between 300kg/year and 2,170kg/year for the new building and from 245kg/year up to 3,221kg/year for the refurbished house, respectively. In both cases, SAGSHP systems proved to be a feasible practice for greater energy independence from non-renewable energy sources with substantial positive impact on the greenhouse gasses emissions
Application of the superposition technique in conduction heat transfer for analysing arrays of shallow boreholes in ground source heat pump systems
The production of Wara cheese from locally sourced coagulants and its nutritional evaluation
The use of vegetable extracts as milk coagulants has evolved recently in soft cheese processing. In this study, two types of cheeses were produced from locally sourced raw cow milk using two different coagulants, Calotropis procera leaf and CaCl2. Protein, fat, Zn, Mg, and Fe were the nutrients and minerals that were assayed. The protein (18.4%), Fat (7.93%), Mg (4.13%), Zn (4.01%), Fe (2.59%) of Calotropis procera coagulated cheese was significantly higher than CaCl2 coagulant produced cheese with protein content of (9.13%), Fat (5.53%), Mg (2.34%), Zn (2.59%), Fe (1.13%). The higher ash content in the cheese produced with CaCl2 coagulant makes it susceptible to microbial growth, as a result, reducing its shelf-life. The study suggests that cow milk and Calotropis procera produced cheese appears promising in nutritional contents with further quality improvemen
Assessment of cardiovascular risk in a slum population in Kenya : use of World Health Organisation/International Society of Hypertension (WHO/ISH) risk prediction charts - secondary analyses of a household survey
Objectives Although cardiovascular disease (CVD) is of growing importance in low- and middle-income countries (LMICs), there are conflicting views regarding CVD as a major public health problem for the urban poor, including those living in slums. We examine multivariable risk prediction in a slum population and assess the number of cardiovascular related deaths within 10 years of application of the tool.
Setting We use data from the Nairobi Urban Health and Demographic Surveillance System (NUHDSS) population (residents of two slum communities) between May 2008 and April 2009.
Design This is a secondary data analysis from a cross-sectional survey. We use the WHO/International Society of Hypertension (WHO/ISH) cardiovascular risk prediction tool to examine 10-year risk of major CVD events in a slum population. CVD deaths in the cohort, reported up until June 2018 and identified through verbal autopsy are also presented.
Participants 3063 men and women aged over 40 years with complete data for variables needed for the WHO/ISH risk prediction tool were eligible to take part.
Results The majority of study members (2895, 94.5%) were predicted to have ‘low’ risk (20% were identified as dying of CVD.
Conclusions This study shows that there is a low risk profile of CVD in this slum population in Nairobi, Kenya, in comparison to results from application of multivariable risk prediction tools in other LMIC populations. This has implications for health service planning in these contexts
Pozzolanic properties of Waste Agricultural Biomass - African Locust Bean Pod Waste
The increase in agricultural waste such as African locust bean pod have resulted in endangering the life of plants and animals. Researchers have found out ways that this environmental pollution can be of positive relevance by recycling the waste to be re-used or reduce to ensure a cleaner and healthier environment. African locust bean pod was ashed and the pozzolanic properties were investigated. The pod was dried, blended and ashed in a furnace at 500°C for two (2) hours; different analysis was carried out on the ash obtained to prove the pozzolanic properties, such as sieve analysis to determine the particle size distribution; reaction of calcium hydroxide with the ash in relation to time which proved that pozzolanic reactivity increases with time, comparison of hydration of Portland cement with ashed locust bean pod mixture and compressive strength test
The Significance of Scaling Effects in a Solar Absorber Plate with Micro-Channels
The file attached to this record is the authors final peer reviewed version. The publisher's final version can be found by following the DOI link.This paper investigates the significance of some micro scaling effects in micro-channel absorber plates. These plates are to be used in a proposed compact (thin and light-weight) solar thermal flat plate collector (FPC). Forced convection experiments were performed on an instrumented metal plate with micro-channels. Reynolds numbers were in the range 10–100 and fluid inlet temperatures ranged from 5 to 40 °C. Scaling effects such as viscous dissipation and entrance effects had insignificant impact on the measured average Nusselt number. However, conjugate heat transfer and measurement uncertainties were significant. Conjugate heat transfer was found to reduce the Nusselt number which agrees with the literature, this also resulted in a Peclet number dependent Nusselt number. The local Nusselt number was observed to vary axially despite satisfying the criteria for neglecting entrance effects; this variation increased with the Graetz number. It was observed that the position of the thermocouples can result in an under-estimation of the Nusselt number. The results are beneficial for the design and operation of micro-channel absorber plates
A comparison of analytical and numerical model predictions of shallow soil temperature variation with experimental measurements
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.In several fields of enquiry such as geothermal energy, geology and agriculture, it is of interest to study the thermal behaviour of shallow soils. For this, several analytical and numerical methodologies have been proposed to analyse the temperature variation of the soil in the short and long term. In this paper, a comparative study of different models (sinusoidal, semi-infinite and finite difference method) is conducted to estimate the shallow soil temperature variation in the short and long term. The models were compared with hourly experimental measured data of soil temperature in Leicester, UK, at depths between 0.75 and 2.75 m. The results show that the sinusoidal model is not appropriate to evaluate the short-term temperature variations, such as hourly or daily fluctuations. Likewise, this model is highly affected by the undisturbed ground temperature and can lead to very high errors. Regarding the semi-infinite model, it is accurate enough to predict the short-term temperature variation. However, it is useless to predict the long-term variation at depths greater than 1 m. The finite difference method (FDM) considering the air temperature as a boundary condition for the soil surface is the most accurate approach for estimating both short and long-term temperature variations while the FDM with heat flux as boundary condition is the least accurate approach due to the uncertainty of the assumed parameters. The ranges of errors for the sinusoidal, semi-infinite and FDM are found to be from 76.09 to 142.13%, 12.11 to 104.88% and 1.82 to 28.14% respectively
Compositional Analysis of Lignocellulosic Materials: Evaluation of an Economically Viable Method Suitable for Woody and Non-woody Biomass
The determination of the composition of lignocellulosic substrate is a crucial step in order to determine the overall efficiency of the processes designed to convert lignocelluloses to ethanol. Standard methods as gravimetric, chromatography, and spectroscopic are routinely explored in the scientific literature. This paper details our investigations in the application of economically viable gravimetric methods particularly suitable for developing countries. The methods were proven to be reproducible and representative for the analysis of biomass as sugarcane bagasse, siam weed, shea tree sawdust
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