207 research outputs found

    Effect of chemical reaction in a third grade fluid in porous medium analyzed by unsteady magnetohydrodynamic couette

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    An analysis was carried out on unsteady magnetohydrodynamic (MHD) Couette third grade fluid in a porous medium in the presence of chemical reaction parameter. The Darcy’s law and Fick’s law of diffusion were introduced to stimulate the porosity and chemical reaction in the problem. The resulting flow problem was investigated and model of the problem in form of partial differential equations were obtained. He-Laplace method was used to obtain the solution of the equations and expressions for the velocity field, temperature and concentration distribution were given for each case. Graphical results for various interesting parameters were analyzed and presented.Keywords: Plane Couette; Magnetohydrodynamic; Porous Medium; Chemical Reaction Paramete

    Assessment of concentration level of some heavy metals and non -metallic ions in dumpsite soils in the Federal Capital Territory, Nigeria

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    The concentration of heavy metals (Fe, Cd, Cr, Cu, Pb, Mn, Ni and Zn), pH and non-metallic ions (Cl-, NO3- and SO42-) in soil samples from dumpsites and soil samples from areas without dumpsites (control) in the study area were determined at depth 0-15cm, 45-60cm and 85-100cm.The digestion of samples was done using concentrated nitric acid. The Atomic Absorption Spectrophotometer (AAS) and titration methods were used to determine heavy metals and non-metallic ions respectively. At depth 0-15cm, heavy metal concentration in the dumpsite soil in both seasons were; Fe (19.8911 and 21.8488 mg/g), Cd (0.0012 and 0.0017 mg/g), Cr (0.7610 and 0.2285 mg/g), Cu (0.3657 and 0.1259 mg/g), Pb (0.5063 and 0.9991 mg/g), Mn (6.3547 and 3.446 mg/g), Ni (0.2549 and 0.1247 mg/g), Zn (1.2057 and 3.2462 mg/g). In both seasons control Fe (18.0275 and 14.5668 mg/g), Cd (0.0078 and 0.0000 mg/g), Cr (0.1768 and 0.2643 mg/g), Cu (0.0308 and 0.0528 mg/g), Pb (0.0201 and 0.3776 mg/g), Mn (0.0824 and 0.1163 mg/g), Ni (0.0256 and 0.0000 mg/g), Zn (0.0695 and 0.8055 mg/g). Heavy metal contents for soil samples across the profile depth at 0-15cm, 45-60cm and 85-100cm were also significantly higher at P<0.05 from top down wards as well as between soil and control. Assessed parameters for dumpsite soil samples at depth 0-15cm, 45-60cm and 85-100cm all exceeded the WHO international standards in both seasons. It is therefore concluded that the waste dumpsites have negative impact on the quality of soil the study area. As such, there is need for government to overhaul her approach towards management of waste dumpsites and also to develop better waste management practices with regard to municipal solid waste management to mitigate soil pollution and its attendant implications in the FCT.Keywords: Soil Pollution, Waste dumpsite, Municipal Solid Waste Management, Sustainable Developmen

    Accounting for the Effects of Oil Prices on Exchange Rate in Nigeria: Empirical Evidence from Linear and Non-Linear ARDL Models

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    This study empirically examines the impact oil prices on the exchange rate in Nigeria. Time series annual dataset spanning 1980 to 2018 was estimated using the linear and nonlinear ARDL model developed by Pesaran and Shin, (1998) & Pesaran, et al. (2001) and Shin, et al. (2014); where oil prices, nominal exchange rate, interest rate, and oil revenue serves as the variables for analysis.  From the result of the linear-ARDL models  both the long run and short-run revealed that oil price has positive and significant impact on exchange rate. Similarly, the nonlinear model also revealed that in both the long run and the short-run, both the rising and falling oil prices have an increasing impact on exchange rate. Policy implication for the findings suggests that, the authority should hold the exchange rate constant during a stable period of oil prices in order to exert pressure on the foreign currency so that the oil prices will continue to have increasing impact on exchange rate as it was during the rising and falling periods

    Accounting for the Effects of Oil Prices on Exchange Rate in Nigeria: Empirical Evidence from Linear and Non-Linear ARDL Models

    Get PDF
    This study empirically examines the impact oil prices on the exchange rate in Nigeria. Time series annual dataset spanning 1980 to 2018 was estimated using the linear and nonlinear ARDL model developed by Pesaran and Shin, (1998) & Pesaran, et al. (2001) and Shin, et al. (2014); where oil prices, nominal exchange rate, interest rate, and oil revenue serves as the variables for analysis.  From the result of the linear-ARDL models  both the long run and short-run revealed that oil price has positive and significant impact on exchange rate. Similarly, the nonlinear model also revealed that in both the long run and the short-run, both the rising and falling oil prices have an increasing impact on exchange rate. Policy implication for the findings suggests that, the authority should hold the exchange rate constant during a stable period of oil prices in order to exert pressure on the foreign currency so that the oil prices will continue to have increasing impact on exchange rate as it was during the rising and falling periods

    Influence of climate variability and change on natural hazard in selected states in northern Nigeria

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    The study examined the climate variability and change using temperature record (1951-2014) over Kano, Maiduguri, and Sokoto to depict the spatiotemporal influence on natural hazards across the states. Shiroro hydrologic records for thirty seven years (1975-2012) were collected and analyzed in addition, 300 structured questionnaires were administered to the residents of Gurmana downstream settlement for the purpose of generating their responses arising from flooding and its related problems. The result affirmed temperature changes between 1950 - 1981 and 1982 – 2014; it reveals positive changes in April mean, maximum and minimum temperature values of between 0.4 to1.5°C across the study area. Similarly, the observed oscillation and positive trend of inflow and outflow from shiroro reservoir constitute a major and unprecedented shift in stream flow across the downstream communities. Intensified warmer temperature, inflow and discharge trends have continued to aggravate seasonal rainfall related hazards which are threats to sustainability of human livelihood across most rural communities. Consequently, there is need for systematic development and application of policies, strategies and adoption of best practices as pathway towards disaster risk reduction

    Perceptions on the accessibility of Islamic banking in the UK—Challenges, opportunities and divergence in opinion

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    This study examines the views of UK-based Muslims, Islamic Scholars and Islamic banking employees on the current state of the latter industry, both in practical terms and as regards engagement with the nation’s large, but often marginalised Islamic community. The British Government has recently championed the Islamic banking sector and committed to supporting it as a means of addressing financial services needs and consolidating London’s position as the global centre for Islamic investment. The analysis adds to the substantive literature in two principal ways: (i) by contextualising the evidence via the notions of empowerment, engagement and social justice that underpin both the state’s attempts to foster growth and the central tenets of Islam; and (ii) by placing comparison of the opinions of key groups at the heart of the investigation. The findings reveal that while progress has been made, UK-based Muslims see several substantive impediments to access, including the complex terminology of Islamic banking products, the lack of internet banking facilities and branch networks as well as a generalised lack of interest in marketing on the part of the institutions. Whilst some coincidence of perception is evident, the views of bankers are shown to be out of line with those of the other parties in a number of key areas. For example, bankers appear to see less potential in the role of the internet as a medium for spreading awareness than do either potential customers or religious scholars. The paper therefore concludes with a call for multi-party Ijtihad and Qiyas (deductive analogy) that will encourage industrial outreach and, in so doing, support long-term growth

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

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    Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe

    Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

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    The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

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    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
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