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Research Journal of Physics

Semi conducting vanadium glasses with different V2O5
contents have been prepared by rapid quenching technique. Ultrasonic velocities
measurements have been performed over a wide range of temperatures from 1020-1060
K. Elastic moduli, Debye temperature and poisson’s ratio have been obtained
for different V2O5 contents as a function of temperature.
The composition dependence of velocities show a monotonic variation with the
addition of V2O5. Ultrasonic velocity measurements (longitudinal
and shear velocities) were carried by using pulse-echo technique at 5 MHz frequency
showing that the ultrasonic velocity and the glass density are sensitive to
the glass composition and behave identically to each other. The results indicate
that the longitudinal wave velocities, shear wave velocities and elastic moduli
show the same trend with composition. The X-Ray Diffraction spectral (XRD) studies
have been employed to ascertain the amorphous nature of the glass specimen.
To identify the functional groups present in the glass samples and to study
about the morphology of the glass samples, the prepared glass samples are subjected
to optical studies like FT-IR spectroscopy and Scanning Electron Microscopy
(SEM), respectively. Eventually the results are discussed with a view to establish
the structural characterization, compactness and mechanical properties of the
glass samples. 2014/04/12 - 22:52

Knowledge of the optical properties of Gallium Antimonide (GaSb) is important
because of the increasing application of GaSb in many optical and electronics
applications. We have investigated the optical properties of Gallium Antimonide
(GaSb) in the photon energy range 1.5-6.01 eV. We obtained refractive index
which has a maximum value of 5.24 at photon energy 2.0 eV, the extinction coefficient
which has a maximum value of 4.13 at photon energy 4.2 eV, the dielectric constant,
the real part of the complex dielectric constant has a maximum value of 25.6
at photon energy 2.0 eV and the imaginary part of the complex dielectric constant
has a maximum value of 25.14 at photon energy 4.0 eV, the transmittance which
has a maximum value of 0.20 at photon energy 3.3 eV, the absorption coefficient
which has a maximum value of 1.76x108 m-1 at photon energy
4.2 eV, reflectance which has a maximum value of 0.67 at 4.3 eV, reflection
coefficient which has a maximum value of 0.82 at photon energy 4.3 eV, the real
part of optical conductivity has a maximum value of 1.22x1016 at
4.1 eV and the imaginary part of the optical conductivity has a maximum value
of 5.95x1015 at 4.3 eV. The values obtained for the optical properties
of GaSb are in good agreement with other results. 2014/04/12 - 22:52

An aeromagnetic map for Ogbomoso area within longitudes 4°00 and 4°30'E
and latitudes 8°00 and 8°30'N which covers the distance of 55 by 55
km (3025 km2) study area was acquired. The map was digitized, gridded
and delineated into profiles at 100 m interval of which some profiles were selected,
processed and regional gradient removed. Reduction-to-pole of the total magnetic
field intensity was carried out, the contour map and surface distribution of
the magnetic minerals was obtained using semi-automated geophysical software.
To carry out a quantitative analysis and interpretation thin sheet model was
used to study the magnetic anomaly of the area and subsequently determine the
average depth to the magnetic mineral source, magnetic angle and the angle of
dip. The results obtained reveals 150-265.2 m of depth with combined magnetic
angle of 39.8-53.1° and angle of dip of 66.9-81.3°, respectively. The
result from the analysis indicates the presence of magnetic mineral resources
in the locality which spread across the surveyed area while some are found at
fairly near-surface, others are located at a deep region of the crust. 2014/04/12 - 22:52

Sediments are known to contain natural radionuclides but their presence in the sediments beyond certain limits can constitute radiological health effects. Sediments from Ogun river provide large quantities of sand for building purposes. This work aimed at determining the excess lifetime cancer risk associated with the use of the sediments as building material. A total of 320 sediment samples were collected along the course of the river; 60 in the upper region (Igboho to Idi-Ata; Oyo-Ogun axis), 90 in the middle region (Olopade to Mile 8 Oba; Ogun-Lagos axis) and 170 in the lower region (Abata to Apa Osa; Lagos axis). The number of samples collected in each region was determined by accessibility. The activity concentrations of the natural radionuclides in the samples were determined using gamma-ray spectrometer comprising 76x76 mm NaI (Tl) detector coupled to a multichannel analyser. These concentrations together with standard equations were used to evaluate indoor effective dose rates. The regional weighted mean of the Excess Lifetime Cancer Risk (ELCR) values were (0.141±0.01) 10-3, (0.137±0.02) 10-3 and (0.148±0.03) 10-3 for the upper, middle and lower regions of the river respectively. The estimated total value of ELCR for Ogun river sediments was found to be (0.143±0.02) 10-3, ranging from 0.051x10-3-0.290x10-3. This value was lower than the world’s average value of (0.29x10-3). 2013/09/08 - 18:09

The reflectivity of the fiber Bragg grating under different external effectors is discussed. The effect of Co60 gamma radiation on the effective refractive index of nine profile of apodized chirped Bragg grating has been studied, comparisons between the reflectivity of the gamma irradiated and non irradiated fiber Bragg grating has been investigated. The electric field of these signals in the apodized chirped Bragg grating is first calculated from which, the new values of the refractive index are determined. The nonlinear effects appear on the reflectivity of traveling signals. The grating is also affected by the undersea level temperature and pressure. The irradiated Sinc profile is the profile having the greatest reflectivity (R≈0.99 in the nonlinear case). 2013/09/08 - 18:09

Electrical resistivity equipment was fabricated to demonstrate some model studies
within the complex terrain of southwestern Nigeria. The equipment contains two
multi-meters, a bridge diode, a capacitor and reversing switches. A 12 V car
battery was used as power source with commercially available 400 W inverter
that produces an Alternating Current (AC) “modified”
sine wave from the 12 V Direct Current (DC) source to increase the voltage required
for several measurement. Model results with Schlumberger array are presented
and these show a fairly good correlation with ABEM 300 B TERRAMETER when compared
their results. 2013/09/08 - 18:09

In this study, an attempt has been made to grow large size optically transparent LA single crystals by slow evaporation solution growth technique at room temperature. The chemical composition of the grown crystals was determined by Energy Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) Spectroscopy. The structure of pure LA crystal has been examined by powder X-ray Diffraction (XRD) study. Optical properties of the grown crystal were studied using UV-Visible spectroscopy at room temperature. DC electrical conductivity was measured at different temperatures ranging from 35-140°C by conventional two probe method. Powder XRD analysis confirms the orthorhombic structure of the grown crystals. The transmission in the visible region and DC electrical conductivity of the crystal was found to increase with temperature and doping concentration. Optically transparent, large size and electrically conducting LA crystal were grown successfully in a laboratory for useful application in optoelectronic devices. 2012/07/18 - 07:14

A dusty plasma system containing non-thermal electron distributions, Boltzmann distributed ions and mobile charge fluctuating positive dust has been considered. The nonlinear propagation of the dust-acoustic (DA) waves in such dusty plasma has been investigated by employing the reductive perturbation method. The effect of non-thermal electrons on the height and thickness of DA shock waves are also studied. It has been found that the thickness of the Dust acoustic shock composition decreases as the non-thermal parameter increases, while the amplitude of the shock composition thickness varies with the charge fluctuating dust. 2012/07/18 - 07:14

The effect of temperature on electrical and ionic transport properties of PMMA-SA-OA Gel Polymer Electrolyte (GPE) system have been studied in this work. The GPEs have been prepared via solution casting technique and investigated in the temperature ranges from ambient to 368 K. Electrochemical Impedance Spectroscopy technique has been employed to determine the behaviors. The conductivity of the GPE is 8.65x10-4 S cm-1 at ambient temperature and increases to 1.93x10-2 S cm-1 at 368 K. The GPEs show non-Debye type of materials where the regression value obtained from the log conductivity versus reciprocal temperature is close to unity (R2~1). The complex permittivity, electrical modulus and tangent loss study shows the plurality of relaxation process, thus confirm the Grouttus’ mechanism process occurred in the GPE system. The activation energy calculated decreases with temperature. The conductivity shows significant influenced of the ionic transport properties i.e. number of ions (n), mobility of ions (μ) and diffusion coefficient of ions (D). 2012/07/18 - 07:14

The abundance of crystalline rocks in Ogun State has resulted in increasing number of quarry activities and sites. These rocks which have been observed to be rich in Naturally Occurring Radionuclides (NOR) are the primary terrestrial sources of radiation in the environment. This study measured the gamma radioactivity level in bedrocks and soils of quarry sites in Ogun State, South-Western, Nigeria. Measurements of radiation were made randomly at 10 locations in each of the 20 quarry sites using fluke-victoreen ASM-990 survey meter. The measured dose rates above the bedrocks and soils of the quarries ranged from 2.3-19.4 and 2.7-19.4 nGy h-1 which corresponding to annual effective dose ranges of 2.60-23.81 and 3.31-22.30 μSv y-1, respectively using occupancy factor. Similarly, the result of linear regression between the measured absorbed dose rate on top of the bedrocks and top of the soils in the 20 quarry sites revealed that there is a strong positive correlation (R2 = 0.80) which implies that, the radiation from the soil of the study area are derived from the underlying rocks. The mean absorbed doses of this study were low compared to values from other studies and world recommended value of 70 μSv y-1. However, no matter how low, all levels of ionizing radiation are hazardous to human health. Hence, there will be need for continuous monitoring of the radiation level in and around the quarry sites. 2012/07/18 - 07:14

The seismic refraction investigation was carried out using the seismograph and it involved twenty-two profiles spread over three traverses with 24 spreads per profile along the major path that passes through the Golden Heritage Estate. A distance of 72 m per profile was utilized for seismic refraction survey. The result shows that the seismic refraction layers delineated were three and first one have an average velocity of 736 m sec-1 and thickness of 2-6 m, indicating topsoil. Seismic layer 2 on its part has an average velocity of 1468.18 m sec-1 and thickness 3-8 m, indicating laterite. Then the third seismic layer has an average velocity of 2272.73 m sec-1 and thickness of 5-12 m, indicating sand. These layers delineated by seismic refraction are characterized by velocity increase with depth. The sand units in the layers delineated acts as the aquifer units. Also the seismic refraction survey could not image the second, third and subsequent aquifers due to the weaker energy source used, hence, it is suggested that for future studies in order to be able to map deeper horizons, stronger energy source should be used. 2012/06/20 - 00:46

Transverse modes of electromagnetic fields are proposed to be encoded as qubits for simulating quantum computation. The method relies on simple optical devices such as Mach-Zehnder Interferometer (MZI) and phase shifter built on 2-transverse-mode-waveguides. The possibility of this encoding scheme was designed, simulated and verified through rigorous numerical analyses using the Beam propagation method. The proposed logic gates have the potential of being more compact and easily realizable than some other optical implementation proposals since it is based on planar light wave circuit technology. 2012/06/20 - 00:46

In this study, we prove that the neutron has infinitesimal negative electrical charge which is also in agreement with the neutrality of the free neutron. In some previous experiments it has been shown that neutron have negative electrical charge of order 10-18, now by using simple classical physics we confirm theoretically the results of the previous experiments and find that the infinitesimal negative charge of the neutron is due to gravity. 2011/12/27 - 15:22

In the framework of gravitational theory of general relativity, this article has systematically and radically solved the problem of galaxy formation and some significant cosmological puzzles. A flaw with Einstein’s equation of gravitational field is firstly corrected and the foundations of general relativity are perfected and developed and space-time is proved to be infinite, expansion and contraction of universe are proved to be in circles, the singular point of big bang is naturally eliminated, celestial bodies and galaxies are proved growing up with cosmic expansion, for example Earth’s mass and radius at present increase by 1.2 trillion tons and 0.45 mm, respectively in a year, in response to which geostationary satellites rise by 2.7 mm. 2011/12/26 - 15:44

A review is presented of the state of pion condensation in the nuclear medium (neutron matter, symmetric nuclear matter and neutron stars). This phenomenon has critical consequences for both nuclear physics and astrophysical systems and processes. Initial studies had focused on determining the critical density of the medium that will signal the onset of this phase transition, but recent developments have focused on a description of nuclear and astrophysical systems in the presence of the pion condensate. The approach in this review is to first present the general physical principles and mathematical formulations and then use specific examples to summarise their applications. The study discusses factors that enhance or inhibit condensation, σ-model of pion condensation, finite temperature equation of state of a pion condensed system, effect of chiral symmetry, relativistic models of pion condensation, the influence of pion condensation on the gravitational stability of neutron stars and the influence of magnetic fields on pion phase transition. 2011/02/03 - 03:23