Open Access Original Research Article

Computation of Radiation Risk Parameters Due to Gamma Radiation Doses from Some Rivers within Oil Producing Communities of Abia State, Nigeria

Paschal Ikenna Enyinna, Gregory Onomakere Avwiri

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2016/28041

Oil production involves the extraction of petroleum, gas and produced water, with some associated natural radionuclides from the sub-surface which could enhance background ionization radiation. This study presents the radiological analyses and computation of radiation risk parameters due to gamma radiation doses from some water samples collected from some oil producing communities in Abia State, Nigeria. The measurement was carried out using Sodium Iodide detector that is activated by thallium, and the radiological risk parameters computed were the annual effective dose of radiation due to ingested water (EDIW), the Annual Gonadal Dose Equivalent (AGDE) and the Excess Lifetime Cancer Risk (ELCR). The computed radiological risk parameters show that the annual effective dose of radiation due to ingested water by an individual ranged from 1.89 mSv y-1  to 3.52 mSv y-1 and exceeded the 0.1 mSv/yr permissible limit recommended by the International Commission on Radiological Protection (ICRP). The Annual Gonadal Dose Equivalent ranged from 0.041 mSv y-1 to 0.075 mSv y-1 and is below the World average value of 0.3 mSv y-1. The Excess Lifetime Cancer Risk ranged between 5.30 x 10-3 and 9.87 x 10-3 and is above the World average value of 0.29 x 10-3. The elevation of most of the radiological risk parameters may be attributed to oil production activities within these environments and may likely have negative impacts on the inhabitants who consume the water and also use it for other economic activities.

 

Open Access Original Research Article

Influence of Topography on Surface Radio Refractivity Patterns over North Central, Nigeria

O. O. Ajileye, I. S. Kolawole, J. O. Ogbole, A. T. Alaga, A. S. Halilu, S. O. Mohammed

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2016/27436

This paper investigates the interaction between terrain features and surface refractivity during the past decades in the North Central, Nigeria. Some issues were addressed in the study namely seasonal variation of surface refractivity over a period of 25 years (1983 – 2007), spatial distribution of surface refractivity covering 287 stations spreading across the Nigerian middle belt and relationship between terrain features and spatial variation of surface refractivity. Satellite-measured meteorological parameters comprising air temperature, relative humidity and pressure at 2 m height (relative to the surface) were obtained from National Aeronautic Space Administration (NASA) and used to compute annual, January and July averages of surface refractivity over the period. The results of surface refractivity were interpolated and compared with North Central terrain features to establish a correlation. Surface refractivity reduced with increasing altitude across the North Central, Nigeria; the reduction at interval of 100 m height was at an average of 1.27 N-Units. On the average, refractivity gradient varied at the rate of 7.87 N-Units/km. The least altitudinal variation occurred at the boundary layer while the highest variation occurred at 800 m and above. Surface refractivity and refractivity gradients at North Central, Nigeria were influenced by topographical features and the prevailing atmospheric conditions which are dependent on the seasonal rainfall regimes.

 

Open Access Original Research Article

Energy Generation Using Thermoelectric Power Generator (TEPG) from the Living Body

A. R. M. Siddique, S. H. Majid

Physical Science International Journal, Page 1-15
DOI: 10.9734/PSIJ/2016/27900

In this paper, a general idea about wearable thermoelectric generator from the body heat has been discussed. First, a thermoelectric generator, which is usually used for industrial purposes (Tellurex-G2-40-0329 series), was used for lab experiment to observe the output results at the low-temperature difference (i.e., ΔT=6-18 K). At this temperature range, the power output was approximately 0.0192-0.35 µW which was very low for practical use. Different configurations of TEG (single, double, single TEG with fin, etc.) were used to find out the best one, which could generate maximum power. It is found that a single thermoelectric generator with a fin can harvest a maximum power output of around 2.5 µW. A list of low temperature-based, thermoelectric n-type and p-type materials was presented. n-type 75% Bi2Te3, 25% Bi2Se3 and p-type 25% Bi2Te3 0.75% Sb2Te3 (1.75%Se) were used for numerical and finite element analysis for wearable thermoelectric generator. A maximum of 6.5 µW power can be harvested from body heat when body temperature is 37°C and the ambient temperature is considered as 25°C (ΔT =12 K) for this thermoelectric element. Maple, FlexPDE, and SolidWorks were used for numerical analysis and finite element analysis (FEA).

Open Access Original Research Article

Models of Extra Dimensions and Searches for Kaluza-Klein Modes at the LHC

Obikhod Tetiana, Petrenko Ievgenii

Physical Science International Journal, Page 1-10
DOI: 10.9734/PSIJ/2016/28096

We have considered the theories of extra dimensions from Large Extra Dimensions and Randall-Sundrum models to the E8 × E8 heterotic sting theory identified with the 11-dimensional M-theory. Within the three models of extra dimensions and with the help of computer program PYTHIA were calculated the production cross sections for Kaluza-Klein gravitons and Kaluza-Klein vector bosons with the cms energy range 2 -14 TeV at the LHC. It was performed a comparison of the theoretical predictions with the data of computer modeling and found a satisfactory agreement. Searches on heavy gauge bosons performed by the ATLAS and CMS experiments collected during 2012 at the LHC were used for comparison with our calculations for masses of Kaluza-Klein gauge boson. The obtained results are important for future searches of Kaluza-Klein gravitons and vector bosons with the cms 14 TeV at the LHC.

 

Open Access Original Research Article

Computation of the Cohesive Energies of NaCl, SiO2 and Al Using Density Functional Theory

Aungwa Francis, S. G. Abdu, Ali Haruna, Eli Danladi

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2016/26479

In this paper, the cohesive energies of Sodium Chloride (NaCl), Silicon dioxide (SiO2) and Alum inum (Al) based on computer code FHI-aims were calculated using Density Functional Theory. The code has several input parameters in which some of the variables were optimized. The cohesive energies of NaCl, SiO2 and Al were calculated within Local Density Approximation (LDA) of Perdew Wang of the density functional theory. The results obtained from the computation of the cohesive energies of  NaCl, SiO2 and Al were 8.38 eV, 12.32 eV and 3.64 eV respectively which is in good agreement when compared to the experimental values of 8.18,12.94 and 3.39eV for NaCl, SiO2 and Al respectively. These energies are within reasonable percentage errors of 2.4%, 4.8% and 6.9% respectively.

 

Open Access Original Research Article

Timescales of Anthropogenic and Total Carbon Dioxide (CO2) in the Atmosphere

Antero Ollila

Physical Science International Journal, Page 1-19
DOI: 10.9734/PSIJ/2016/27004

The author has enhanced the original one dimensional semi-empirical atmosphere-ocean-biosphere model 1DAOBM based on the four-box presentation. The improved 1DAOBM-2 contains two major parameters, which have been tuned to adjust the total CO2 net flux rate and the anthropogenic net flux rate from the surface ocean into the deep ocean based on the observed values. The surface ocean part is based on the known dissolution chemical equations according to Henry’s law depending on the atmospheric CO2 concentration and the surface ocean temperature. Simulations have been used to calculate the dynamic responses to the step changes from the actual fossil fuel rate to zero in 1964. The results show that the anthropogenic CO2 decay rate follows very accurately the observed decay rate of radiocarbon 14C having the residence time of 16 years. This is the expected result according to nature of anthropogenic CO2 in the system of the atmosphere, the ocean and the biosphere. The decay rate of the total CO2 in this system is much longer having the residence time of 55 years matching the adjustment time of 220 years. The simulations of the atmospheric net CO2 rate by 1DAOBM-2 from 1960 to 2013 confirms the earlier results that the coefficient of determination r2 = 0.75 (r2 = 0.81 eliminating the Pinatubo eruption effects). The simulations also show that the present anthropogenic CO2 fraction in the atmosphere is 8.0%, and it explains the observed δ13C value of -8.4‰ extremely well. The problem of the sink between the ocean and the biosphere could not be solved totally. A mass balance study shows that before 1956, the ocean and/or the biosphere acted as a source for the total CO2 increase in the atmosphere and thereafter as a sink. This study suggests that the division ratio between the ocean and the biosphere is 60% / 40% for the period from 1750 to 2013. The high correlation between the ocean uptake and the net increase of the total atmospheric CO2 strongly indicates that the ocean has been the sink after 1956.

 

Open Access Original Research Article

Chemical and Electrochemical Deposition of Ag onto Si for Fabrication of Si Nanowires and the Seebeck Effect Characterization

David Rodriguez, Yong X. Gan

Physical Science International Journal, Page 1-10
DOI: 10.9734/PSIJ/2016/27566

In this work, vertically aligned porous Si nanowire (SiNW) arrays were successfully fabricated on two sides of an n-type Si wafer substrate. Ag nanoparticles (NPs) were first deposited onto the Si substrate via two different deposition methods, chemically and electrically (cyclic voltammetry), afterwards the metal assisted chemical etching (MaCE) technique was implemented to fabricate the SiNWs. The thermoelectric property of the SiNWs/Si/SiNWs structure was characterized by the Seebeck coefficient (S) which was measured at room temperature. Our results show a higher S when Ag NPs were electrodeposited onto the Si wafer piece compared to chemical deposition. The S enhancement is times and  times in comparison to that of bulk Si and Ag chemical deposition samples, respectively. The electrodeposition created a strong adhesion between the Ag NPs and Si substrate which ensured a more uniform dispersed SiNWs producing a higher S. The improved thermoelectric performance coupled with electrodeposition of Ag indicates that the SiNWs/Si/SiNWs structure is an excellent candidate for the application in high-performance thermoelectric devices.