Open Access Original Research Article

Temporal and Spatial Variability of Tropospheric Ozone in Nairobi City, Kenya

Julius M. Kimayu, Peter Gikuma-Njuru, David K. Musembi

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2017/31452

In both developed and developing nations urban air pollution is increasingly being recognized as a major public health and environmental issue. Poor or deteriorating air quality in many cities results from high levels of energy consumption by industries, transport and domestic use. The nature of air pollution is dependent on the source profile of the city and the presence of sunlight to promote production of secondary pollutants, such as ozone, through photochemical reactions. The study sought to analyze the surface ozone over Nairobi city, and identify the source of the surface ozone. Nairobi city is one of the fastest growing industrial and economic hubs in East Africa. Increased population which results in increased production and transport activities is therefore expected to increase the surface Ozone which is likely to cause a lot of negative effects to both fauna and flora beings. Surface ozone data for Nairobi was obtained from Kenya meteorological department ranging from 2011 to 2014; another set of data was collected from four sampling sites to determine the special variability and source of the surface ozone over Nairobi area. Analysis meteorological field from National Centre for Environmental Prediction -National Centre for Atmospheric Research (NCEP- NCAR) was used in running Hybrid Single Particle Lagrangian Integrated (HYSPLIT) model. From the analysis it was found out that June July August experiences the highest ozone levels as compared to the other months of the year in both lower and upper levels. This is due to incursion from the south according to the backward trajectories from the HYSPLIT model, which has been proven to have high ozone concentration during this season due to high biomass burning. On the other hand, the diurnal variation of ozone in the four site: Industrial area, Nakumatt Junction, Landhies road and Pangani Round about showed low amount in the early morning and at night hours, with the peak realized during the day. The peak in midday is due to the fact that surface ozone is produced by photochemical oxidation of precursor gases that are produced by motor vehicle and industries. The highest eight-hour mean was 20.2 ppb from Industrial area site, which is below the WHO mean of 51 ppb. Therefore, no much health effects are expected due to the exposure to ozone. This study recommended that there should be a continuous monitoring of ozone and other gases that are harmful to human health for better understanding and advice to the citizen.

 

Open Access Original Research Article

Dielectric Properties of 1-ethyl-3-methyl-imidazolium Tetrafluoroborate (EMIM-BF4) Using Cole-Cole Relaxation Model

T. J. Ikyumbur, E. N. Asagha, E. C. Hemba, J. A. Bash

Physical Science International Journal, Page 1-6
DOI: 10.9734/PSIJ/2017/31315

The Cole-Cole relaxation equations were derived from the Debye equation. The dielectric constant E’ and loss factor E” of EMIM-BF4 were fitted using the derived equations at temperature range of 5°C to 65°C and frequency range of 0.1GHz to 10GHz. The result obtained shows that the dielectric constant and loss factor of EMIM-BF4 were higher at low frequency (i.e. f =0.1GHZ and decrease as the frequency increases. The dielectric constant also increases with increase in the temperature except at 0.1GHz. At 15°C there was a sudden increase in the dielectric constant especially as the frequency increases beyond 5GHz. This sudden increase in the dielectric constant of EMIM-BF4 may be due to the phase change of EMIM-BF4. The loss factor of EMIM-BF4 was generally small for all frequencies and temperatures. This may be due to the fact that EMIM-BF4 consumed less energy when subjected to an applied field.

Open Access Original Research Article

Theoretical Computation of Magnetic Flux Density within the Vicinity of Rukpokwu 11 KV Distribution Power Lines

P. I. Enyinna, A. N. Orlunta

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2017/30035

Horizontal conductors used for distribution of electrical power generate magnetic fields around the vicinity of the conductors due to the flow of current. In the absence of a well calibrated magnetometer, theoretical estimation of the magnitude of the magnetic flux density around these power lines is possible and recommendable. In this study, we calculated the magnetic field exposure from extremely low frequency magnetic field around 11 kV power distribution lines at Rukpokwu, Rivers State, Nigeria using theoretical and mathematical formulations. 32 sample points were considered at horizontal distances of between 1 m and 1000 m from the foot of the vertical pole subtending the electrical conductors. We used a mathematical software (Wolfram Mathematica 8.0) to generate the initial results of the magnetic field current coefficients (Icoef) for the vertical and horizontal components of the magnetic fields and the total magnetic fields for x=1 to 1000 m (horizontal distance from the foot of the pole) for a vertical height of 1 m above the ground surface (considered to be the average height of head positions of the workers and the public within the vicinity of magnetic field). The results showed that for horizontal distances of between 1 and             10 m, the magnetic field exposures ranged from 45.82T/hr to 21.62T/hr and are above the occupational field exposure limit of 21.0 set by International Committee on Non Ionizing Radiation Protection (ICNRIP). Also, the results of field exposure for horizontal distances ranging from 1 to 20 m were between 45.82 and 8.3 and are above the ICNRIP limit of 4.2 set for the public. It is recommended that between horizontal distances of 1 and 10 metres from the distribution lines, relevant government agencies and the populace should discourage the building of shops for businesses, and between the horizontal distances of 1 to 20 metres, they should discourage the building of residential areas, since doing business and residing within these stipulated distances may not be very safe as a result of the magnetic field exposure.

 

Open Access Original Research Article

Computer Modeling of Properties of Superparticles

Obikhod Tetiana

Physical Science International Journal, Page 1-7
DOI: 10.9734/PSIJ/2017/31669

The properties of superparticles within Constrained Minimal Supersymmetric Standard Model (CMSSM) using experimental data obtained at the LHC were studied. The first run of the LHC made it possible the selection of experimental data for purposeful SUSY searches at energies of 13 TeV. Measurements of masses of Higgs boson and top quark, which led to a conclusion about instability of electroweak vacuum, searches for missing transverse energy and charged superparticles, the mass of Higgs boson predicted by SUSY model are good indicators for determining of the four SUSY searches scenarios. Within CMSSM model with the help of computer programs SDECAY and PYTHIA 8.2 were calculated masses, decay widths, cross section for production of superparticles at the center of mass energy of 13 TeV and 33 TeV. The obtained data allow to conclude about the increasing of the production cross section of the superparticles at higher energies and provide the prediction of the most important decay channels of light superparticles. These results give concrete predictions for further SUSY searches at the LHC.

 

Open Access Original Research Article

Radioactivity Levels in Maize from High Background Radiation Areas and Dose Estimates for the Public in Tanzania

Leonid L. Nkuba, Yesaya Y. Sungita

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2017/31697

Natural radioactivity levels in maize which is one of the staple foods in various regions in Tanzania have been studied. The radioactivity concentration of 238U, 232Th and 40K were determined using γ ray spectrometry employing HPGe detector of relative efficiency of 51%. The average radioactivity concentrations in maize from five regions were ranged from 1.8 ± 0.2 to 23.6 ± 0.7 Bq/kg for 238U, 2.2 ± 0.1 to 38.9 ± 1.0 Bq/kg for 232Th and 42.0 ± 0.4 to 434.6 ± 18.7 Bq/kg for 40K respectively. Total annual committed effective dose due to total 238U and 232Th intakes as a result of consumption of maize in five Regions were as follows; Manyara (1.46 mSv/y), Mbeya (0.31 mSv/y), Dodoma (0.21 mSv/y), Ruvuma (0.19 mSv/y) and Dar es Salaam (0.08 mSv/y). The dose value from Manyara was almost the same to the annual dose guideline for the general public which is 1 mSv/y, where as for other regions the doses are low. Hence a conclusion could be made that food crops cultivated at Minjingu village might expose the population to high radiation dose which might be detrimental to their health.

Open Access Original Research Article

Characterization of Worst Month Statistics for Satellite-Earth Links Performance in Tropical Locations

O. M. Durodola, J. S. Ojo, M. O. Ajewole

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2017/31899

The increasing development in satellite technology has brought about several novel mobile satellite services and applications. Consequently, there is a pressing demand for seamless data transfer and accessibility to satellite-earth microwave links in SHF/EHF frequency bands. However, rain has been the major degradation parameter for the availability of satellite signals especially at frequencies greater than 10 GHz. In this paper, we present some statistical analysis of rainfall in two tropical locations in Nigeria – Akure (7°17’N, 5°18’E, 358 m) in the Southwest, and Jos Plateau (9°57’N, 8°58’E, 1192 m) in the north central. Rainfall intensities of one-minute integration time were measured for 19 months (June 2013 to December 2014). Predicted results showed that rain induced attenuation values above 30 dB occurred during the worst months, while clear sky values are below 2 dB. The worst month statistics obtained were largely different from those proposed by the ITU. Thus, for optimum link budgeting, the modified values of Q and ß should be adapted in these regions. The results will facilitate improved radio-communication planning in the region. More investigation on beacon measurements of rain-induced attenuation is required to corroborate these results.