Open Access Original Research Article

Temporal Variations in Ambient Carbon Monoxide Concentrations between Weekdays and Weekends in Akure Central Business District, South West Nigeria

G. A. Afuye, V. N. Ojeh

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2017/35279

The temporal variations in ambient carbon monoxide (CO) concentration has been investigated between weekdays and weekends through the analysis of a year-long measurement data between March 2009 - February 2010 taken at the central business district in Akure, Nigeria. This area has air pollution problems, and the study of the weekdays-weekends effects is used as a tool to plan and develop strategies for air pollution mitigation measures considering the on-going extremely rapid urban growth. CO was measured using portable Lascar EL-USB-CO sensor and logger mounted 3 meters above the ground on a lamp post with a sampling frequency of 30 seconds. 1 hour and 8 hour averages were then computed from the raw data using descriptive statistics: weekly evolution, weekdays-weekends differences and average daily difference between weekends minus workdays were computed and hypothesis on the difference in holiday and non-holiday carbon monoxide concentrations was tested. Based on daily parameters and weekend-weekday differences, all the measured air pollutants exhibited clearly reduced concentrations. Results show distinct weekdays and weekend variations with respect to traffic rush hours. Weekdays exhibited two peaks that coincide with morning rush hours to work and evening rush hours back home. Weekends had two and one peak related to traffic for morning church service and evening social outings respectively. The highest CO concentrations during the morning and evening rush hours for 1 hour averages were 12.57 ppm and 14.51 ppm for weekdays and 8.50 ppm and 14.62 ppm for weekends respectively. While the highest CO concentrations during the morning and evening rush hours for 8 hour averages were 9.57 ppm and 13.17 ppm for weekdays, it was 8.40 ppm and 11.72 ppm for Sunday morning and evening peaks respectively, for Saturday the value was 14.51 ppm. Weekdays CO concentration for daytime mean 1 h values of 8-20 ppm and daytime mean 8 h values of 4-12 ppm were observed while the weekends concentration exhibited a consistent similar cyclic diurnal pattern throughout the week, with daytime mean 1 h values of 2-10 ppm and day-time mean 8 h values of 4-8 ppm. The magnitude of the differences between mean weekdays and weekends CO concentration during December, January, February (DJF), was 45% compared to 21% between March, April, May (MAM). While June, July, August (JJA) was 18% compared to 16% between September, October, November (SON) in the central business district.


Open Access Original Research Article

Thermal Performance of a Receiver Located in the Caustic Area of a Cylindro-Parabolic Solar Concentrator

B. M. Pakouzou, M. S. T. Ky, S. T. Gbembongo, G. P. Ouedraogo, O. A. Mackpayen, B. Dianda, S. Kam, D. J. Bathiebo

Physical Science International Journal, Page 1-14
DOI: 10.9734/PSIJ/2017/37156

Indirect solar dryers with solar collectors, do not always make it possible to reach the desired temperature level and drying time. As part of the improvement of the thermal performance of these systems, a study of the caustic zone is first presented. It is in this zone that the tubular receiver of the studied insolator is placed. The system of equations obtained results from the division of the insolator into fictitious slices of length dz, in which the thermal balance is established. It is solved using an iterative method with finite differences. The volumetric flow rate and the temperature of the heat transfer fluid which can be injected into the drying cage during a day are thus determined at the outlet.

Open Access Original Research Article

A Geophysical Investigation of a Solid Waste Landfill Using Vertical Electrical Sounding Method in Aluu Community, Rivers State, Nigeria

R. Bello, Nwafor J. Chinedu, Obute L. Chinyere, Abiona S. Olawuyi

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2017/37120

Vertical electrical sounding was conducted at a solid waste landfill in Aluu community for a hydro-geophysical assessment of the contamination of soil and groundwater. The ABEM Terrameter employing the Schlumberger array was used for direct current resistivity model using a maximum electrode separation of AB/2 of 100 m. The acquired data was processed and interpreted using IPI2win software to produce ‘A’ type curve as well as resistivity and the thickness of the layers with depth. From the result, five layers were obtained and the first layer has a resistivity of 34.7 Ωm with a thickness of 1.84 m and was interpreted as the top soil. Underlying the first layer is a second layer with a resistivity value of 114 Ωm with a depth of 4.29 m and thickness of 2.45 m was interpreted as lateritic sand.  The third layer with resistivity value of 215 Ωm with depth of 11.1 m and thickness of 6.83 m was interpreted as sand. There is a fourth layer with resistivity value of 605.0 Ωm with depth of 41.8 m and thickness of 30.6 m was interpreted as coarse sand and this could be the probable aquiferous zone. The fifth layer with resistivity value of 165 Ωm with undetermined depth and thickness was interpreted as clay.  The results revealed that the surrounding soil and groundwater close to the landfill have actually been contaminated to depth exceeding 11.1m which is well within the groundwater aquifer system in the area.


Open Access Original Research Article

Mesoscopic RLC Circuit and Its Associated Occupation Number and Berry Phase

Eric Greenwood

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2017/37327

In this paper we consider the quantization of the time-dependent harmonic oscillator and its associated Berry phase using the invariant operator method, as well as the occupation number of the induced quasi-particle production. Furthermore, we point out that in the literature there exist different methods for determining the solution to the Milne-Pinney equation, which leads to different results. By measuring the time-dependent occupation number and associated Berry phase, one can, in principle, determine which of these methods leads to physically realized results. As a concrete example, we consider the mesoscopic RLC circuit and derive the occupation number and associated Berry phase for each of these different methods. We find that, the solution to the Ermakov  equations leads to a time-dependent occupation number and associated Berry phase, while the particular solution to the Milne-Pinney equation does not.

Open Access Original Research Article

Multi-phonon Raman Scattering in GaAs/Al0.28Ga0.72As Super-lattice

Cheng Xing-Kui, Zhou Jun-Ming, Huang Qi, Yan Xun-Ling

Physical Science International Journal, Page 1-7
DOI: 10.9734/PSIJ/2017/37435

Raman scattering measurement of GaAs/Al0.28Ga0.72As super-lattice has been performed by an incident light with the wave-vector perpendicular to super-lattice growth axis at room temperature. Several peaks in Raman Scattering spectrum are observed. Theoretical analysis shows that           the peak at 290 cm-1 may be caused by emission of a longitudinal optical phonon in GaAs/Al0.28Ga0.72As super-lattice, the peak at 584 cm-1 by emission of two ones, and the peak at 876 cm-1 by emission of three ones. The multi-phonon Raman scattering may be resulted from the folded optical phonons in super-lattices.