Open Access Original Research Article

Spatio–Temporal Characterization of Land Surface Air Temperature Anomaly over Nigeria

O. O. Ajileye, S. S. Aladodo, A. B. Rabiu

Physical Science International Journal, Page 1-9,
DOI: 10.9734/psij/2019/v21i330108

In this study, seventeen gridded stations across the latitude over Nigeria were selected with a view to determine and characterize land surface air temperature anomaly for both minimum and maximum values. The study intends to present graphic illustrations of spatial and temporal variations of land surface air temperature anomaly within a period 2008 – 2013.

Long-term averages of minimum and maximum land surface air temperatures were obtained from National Aeronautic and Space Administration satellite meteorological dataset (1983 – 2007). Also, monthly and annual averages of land surface air temperatures were obtained from to compute monthly anomaly, annual anomaly and percentage departure of minimum and maximum land surface air temperatures within a period of 2008 – 2013.

The results showed that Jos had consistently experienced -10.8 and -4 percent decrease in minimum and maximum LSAT anomaly for the period under review. The implication is that Jos is getting colder than usual. The minimum LSAT anomaly declined by -2.8 percent in Lagos. Other stations across Nigeria showed a considerable percentage increase in minimum LSAT anomaly led by Yola (19.5%), Sokoto (18%) and Katsina (15.5%). Inland stations had percentage increase of minimum LSAT anomaly ranging between 5.8% and 10% except in Osogbo where the percentage increase was 1.8%. Osogbo is a less populated capital city of Osun state with active agricultural activities as heat sink. Percentage increase of minimum LSAT anomaly was not significant in Nigerian coastal areas most especially at Port Harcourt (0.5%).

The spatial distribution of maximum LSAT anomaly across Nigerian latitudinal belt, unlike minimum LSAT anomaly, reduced in trend except in Lagos, Makurdi, Abuja, Bida, Minna and Kano. The minimum and maximum anomaly for maximum LSAT was observed at Jos and Makurdi respectively. There are 2 stations to be watched in terms of getting colder in the years to ahead namely Jos and Osogbo while Makurdi and Yola are gradually becoming hotspots.

Open Access Original Research Article

Super-sech Soliton Dynamics in Optical Metamaterials with Generally Parabolic Law of Nonlinearity Using Lagrangian Variational Method

Amour Ayela, Gaston Edah, Camille Elloh, Ga´etan Djossou

Physical Science International Journal, Page 1-9
DOI: 10.9734/psij/2019/v21i330109

Aims/ Objectives: This paper studies the impact of the generally parabolic law of nonlinearity on the evolution of the energy of super-sech soliton dynamics.
Study Design: generally parabolic law of nonlinearity terms study.

Place and Duration of Study: Department of Physics, Faculty of Sciences and Technology(FAST),

University of Abomey Calavi, B´ enin. between Febuary 2018 and January 2019.

Methodology: Variational approach, namely, the Lagrangian Variational Method (LVM) is presented. The different results are obtained using standard fourth order Runge-Kutta method for integration of the system of ordinary differential equation systems.
Results: Dynamics of the different parameters (amplitude, center position, pulse width, chirp, frequency and phase) has been presented with respect to propagating distance.
Conclusion: This study reveals that the generally parabolic law of nonlinearity terms don’t affect the energy of the system but influence the pulse phase.

Open Access Original Research Article

Depletion Analysis of the Nigerian Research Reactor Fuel with 19.75% Enriched UO2 Material

J. A. Rabba, M. Y. Onimisi, D. O. Samson

Physical Science International Journal, Page 1-6
DOI: 10.9734/psij/2019/v21i330110

The depletion analysis of the Nigerian research reactor fuel with 19.75% enriched UO2 have been performed using the VENTURE PC code. The matrix exponential method was selected in this work to perform the depletion analysis. The volume fraction of the materials in this mixture was calculated and multiplied by their respective atom densities to obtain the effective atom density of the nuclide in the water, Aluminium mix region of the fuel cell model. The plot of the variation of k infinity versus hydrogen to Uranium ratio was generated using Matlab programming language for processing of the computer code result. This shows that as the ratio of hydrogen to uranium in the core of the reactor is increased, the reactivity also increases by gradually increasing the fuel cell radii till it gets to the peak of 0.6193. Any further increment in the radius of the fuel cell radii, the reactivity of the reactor decreases as the hydrogen to uranium ratio increases.

Open Access Original Research Article

On Radiative Transfer and Gray Body Parameter for Partially Transparent Media

K. Manuilov

Physical Science International Journal, Page 1-11
DOI: 10.9734/psij/2019/v21i330112

We obtained a solution to radiative heat transfer equations, which describes a multi-layer gray semi-transparent medium in terms of an opaque body. It is shown that the thermal disturbance between the layers of a medium qualitatively changes its optical properties. We introduced a gray body parameter, which allowed us to describe multilayer gray semi-transparent media with low thermal conductivity. We propose a method for calculating heat transfer by thermal radiation in a gray semi-transparent medium and present the results of radiative heat transfer calculations for screen-vacuum and powder insulation materials as examples of such media.

Open Access Review Article

Analysis of the Characteristics of Monthly Rainfall Pattern in Katsina

Emmanuel Vezua Tikyaa, Francis Oladele Anjorin, Emmanuel Joseph

Physical Science International Journal, Page 1-13
DOI: 10.9734/psij/2019/v21i330111

Aims: This paper seeks to analyse the characteristics of monthly rainfall pattern in Katsina City in a view to unveiling the trends and describing its dynamics so that adequate recommendations can be made for its modelling.

Study Design: The analysis involves a complete statistical, trend, spectral and nonlinear analysis of the monthly rainfall time series recorded in Katsina.

Place and Duration of Study: Location: Katsina City, Katsina State, Nigeria from 1990 to 2015; a period of 26 years.

Methodology: Secondary data of daily rainfall recorded in Katsina city from 1990 to 2015 was collected from the Nigerian Meteorological Agency (NiMet), and monthly averages were taken to obtain the monthly rainfall data. The data was then subjected to statistical, trend, spectral and nonlinear analysis techniques to reveal the behavioural patterns in the rainfall and also to reveal its underlying dynamics for its future modelling and prediction.

Results: The outcome of this analysis indicates that the monthly rainfall in Katsina exhibits an increasing trend with high variance and right-skewed distribution requiring a maximum of 6 independent variables to model its dynamics. The correlation exponent plot reached a saturation value of 5.892 confirming that the monthly rainfall in Katsina over the last 26 years exhibits low dimensional chaotic behavior while the largest Lyapunov exponent for the monthly rainfall time series in Katsina was also computed and found to be positive, having a value of 0.006055/month confirming the presence of deterministic chaos dynamics and is predictable for the next 165 months.

Conclusion: Since from the findings of this work it is confirmed that the rainfall in Katsina exhibits chaotic behavior with an increasing trend, it is recommended that more drainages and dams be built to provide steady supply of water for agricultural and domestic purposes as well as curtail the menace of flooding and drought which may occur as a result of global warming and climate change.