Open Access Original Research Article

Mathematical Modelling for Semiconductor and Piezoelectric Media

Ashwani Kumar

Asian Journal of Research and Reviews in Physics, Page 1-12
DOI: 10.9734/ajr2p/2021/v4i430147

In this analysis the importance of mathematical modelling of the physical systems has been outlined. The constitutive relations and basic governing equations of motion for homogeneous isotropic elastic semiconductor (n-type) and homogeneous transversely isotropic ( class) piezoelectric elastic media, in the absence of body forces and electric sources are made non-dimensional in order to reduce the mathematical complexity. All the obtained equations are rewritten in matrix form. Then considering the harmonic wave solution the eigen values and eigen vectors are calculated to obtained the formal solution of the problem.

Open Access Original Research Article

Measurement and Prediction of Received Signal Level and Path Loss through Vegetation

J. T. Zhimwang, E. P. Ogherohwo, D. D. Iliya, Ibrahim Aminu, O. S. Shaka

Asian Journal of Research and Reviews in Physics, Page 13-18
DOI: 10.9734/ajr2p/2021/v4i430148

This paper presents the measurement and prediction of received signal level and path loss through vegetation. Results were estimated under free space, single tree, and vegetation conditions which revealed that the presence of isolated trees along a radio path can affect signal propagation leading to reduction in signal strength (attenuation). The attenuation was found to be dependent on many factors and parameters of the trees e.g. Geometry of measurement, (either trunk or canopy path), state of trees foliation, frequency, canopy thickness among others. In the measured data, high loss values were recorded at canopy geometry which is due to high presence of interacting and attenuating elements at the canopy. Also, high variation in Received signal strength (RSS) was noted at canopy geometry. However, the trend shows variation from path to path. The main factor is the density of tree parameters along the chosen path. Depending on the density of tree parameters along the chosen path, the depth dependence may be extremely slow as seen in the measure data. With this evidence, for radio communication inside woodlands or forests, localizing the two nodes inside the vegetation will certainly give overall best performance in terms of signal impairment. The propagation mechanism in each case are the same at the antenna geometries used following the trend of signal decay. Different transmit antenna inclination angles were used and this has not shown any significant contribution to the excess loss. However, antenna height with respect to the trees canopy showed significant contribution to the excess loss. This information will be useful to network planning engineers in link budget estimation.

Open Access Original Research Article

Thin Films Growth of SnO_2:F/CdS/CdTe, and Studies of Their Physical and Optical Properties using Spray Pyrolysis Techniques

A. O. Musa, A. B. Ahmed, Mansur Said, Mani Tsoho, A. B. Suleiman

Asian Journal of Research and Reviews in Physics, Page 19-31
DOI: 10.9734/ajr2p/2021/v4i430149

Fluorine doped tin oxide, Cadmium Sulphide  and Cadmium Telluride  thin films have been deposted on Soda Lime glass substrate at  respectively by spray pyrolysis (SP) technique and are important semiconductor materials in optoelectronic devices such as optical sensors, light-emitting diodes, transistors and photovoltaic cells.  thin films were characterized by various techniques such as X-ray diffraction, SEM and optical studies. X-ray diffraction measurements show that the deposited   was found to be of cassiterite type with tetragonal rutile structure, observation of peaks of different planes on an X-ray diffraction graph of  thin film showed that  film obtained were cubic structure. The main peak value of  thin film is seen at , which is the characteristic peak of the  compound  and the  film structure was obtained at the major peak  indicating the preferred orientation of  films along  direction. This confirms the formation of  thin film, with (111) as the strongest preferred plane of orientation. The surface morphology of the thin films was analysed by scanning electron microscopy (SEM). The optical energy band gap of thin films are determine  The results showed that the prepared FTO, CdS and CdTe films can be used in solar energy applications.

Open Access Original Research Article

Photon Shielding Characterization of SiO2-PbO-CdO-TiO2 Glasses for Radiotheraphy Shielding Application

Idris M. Mustapha, Atimga B. James, Sulayman M. Bello

Asian Journal of Research and Reviews in Physics, Page 32-38
DOI: 10.9734/ajr2p/2021/v4i430150

In this study, photon attenuation parameters of (30-x) SiO2–15PbO–10CdO-xTiO2, with x = 0, 2, 4, 6, 8 and 10% mol, were determined and their application as shielding material were discussed. The WinXCOM software was used to determine the mass attenuation coefficient of the studied glasses for the energy range (0.015-15MeV). The mass attenuation coefficient of the glass samples first decline up to 0.09 MeV and slightly increase abruptly and then declined uniformly for all the glasses to approximately zero after about 10 MeV.   The effective atomic number (Zeff) was also calculated for the glass samples and were observe to raise from 0.015 to 0.02 MeV and then decreased between 0.02-5 MeV. On account of the dominance of the photoelectric effect in the low energy region, there was a sudden increase in Zeff at about 0.08 MeV close to the absorption edge of the Pb (0.088 MeV). The rapid increment was observed at 0.1–1.5 MeV by transcending typical Compton scattering interaction at intermediate energies for Zeff'’s and began to decrease in the same form again. The lower Zeff   values were found in low and high energy region for all SPCT glasses. The calculated mean free path, half value layer and tenth value layer values were observe to decline as the TiO2 doping of the glasses increased which accounts for the  three photon interaction mechanisms effectiveness in the variation of MFP and HVL values with energy. It can be concluded that SPCT glasses may be considered an alternative material for radiation shielding practices.

Open Access Original Research Article

Determination of Geothermal Gradient from Bore Hole Temperature data in Some Parts of the Eastern Niger Delta Basin

E. D. Uko, M. A. Alabraba, I. Tamunoberetonari, A. O. Oki

Asian Journal of Research and Reviews in Physics, Page 39-46
DOI: 10.9734/ajr2p/2021/v4i430151

An analysis of Geothermal Gradients in the Eastern Niger Delta basin was done using Bore Hole Temperature (BHT) data from three (3) adjacent oil fields. BHT data was converted to static formation temperature by using the conventional method of increasing measured BHT data by 10% and Geothermal Gradient computed using its simple linear relationship with depth, surface temperature and static temperature at depth. Projections were then made for change in Geothermal gradients at 1km intervals to a depth of 4 km. Results obtained showed significant variations across Idama, Inda and Robertkiri fields with average geothermal gradients of 17.3⁰C/Km, 22.6⁰C/Km and 23.1⁰C/Km respectively. Variation in the geothermal gradients in the area is attributed to lithological control and differential rates of sedimentation during basin evolution. Also, results showed that the Geothermal Gradient in the area are generally moderate and could be a good reason for the occurrence of more oil hydrocarbons than gas in the area.