Open Access Short Research Article

Diffuse Reflectance of Powders

Dimitrije Radjenović, Biljana Stojičić, Branislav Radjenović, Marija Radmilović-Radjenović

Asian Journal of Research and Reviews in Physics, Page 1-5
DOI: 10.9734/ajr2p/2019/v2i129799

The propagation of light through powders differs significantly from the propagation of light in a homogeneous material, since the light scatters off points in its path. Colors of powders are related to the fineness of the powder, when the powder is illuminated with white light. As Fourier transform infrared has become more common, the diffuse reflection method has become widely used. Diffuse reflectance is an excellent sampling tool for powdered materials.

Open Access Short Research Article

Scaled-up Analysis of Surface Refractivity across West Africa

O. O. Ajileye

Asian Journal of Research and Reviews in Physics, Page 1-8
DOI: 10.9734/ajr2p/2019/v2i130090

The scaled-up analysis of surface refractivity over a period of 22 years (1983 – 2005) for different climatic zones in West Africa was calculated using the results of surface refractivity at 2 m, and 10 m averaged monthly and annually. The annual surface refractivity normalised value is 0.91 for Z2/Z1, 0.97 for Z3/Z1, and 0.94 for Z4/Z1 at 2 m while the normalised value of surface refractivity is 1.00 for Z2/Z1, 0.98 for Z3/Z1, and 0.96 for Z4/Z1 at 10 m. At 10 m, the value is relatively constant. The monthly variation shows that surface refractivity reduced as latitude increases in West Africa except in wet months for climatic zone 3 at 2 m and wet months in climatic zone 2 at 10 m. The wet months had a characteristic of reduction in normalised surface refractivity value with most severe reduction within latitudes 10°N and 15°N. This decrease in refractivity across the latitude translates into an increase in the velocity of terrestrial propagation across the latitude, resulting in excessive bending of electromagnetic waves toward the earth's surface, along curves with radii less than the radius of the earth.

Open Access Original Research Article

A Theoretical Investigation on Sound Transmission Loss through Multi-walled Plates with Air Space

Toshiaki Natsuki, Jun Natsuki

Asian Journal of Research and Reviews in Physics, Page 1-8
DOI: 10.9734/ajr2p/2019/v2i129801

In this study, an analytical model is proposed to investigate the sound transmission loss through multi-walled plates with air layers or decompression air layers, under the diffuse incidence field. Using the present approach, the influences of various parameters, such as the wall thickness, the decompressed air and the thickness of air space, on the sound transmission loss through are simulated and discussed in detail. It is seen that, due to the wave frequency of mass-air-mass resonance between double-walled glass plates, the sound transmission loss of the plates can be improved at low frequency range. The sound transmission loss tends to increase with decreasing air pressure because the sound is not transmitted through vacuum space. The design method can be used to investigate the effect of various geometric and material parameters on the sound transmission loss. The advantage of the simulation procedure is easily used for designing the layer structures with different parameter to improve the sound insulation effect.

Open Access Original Research Article

In vitro UV-Visible and FTIR Spectroscopy Study of Low Power He-Ne Laser Irradiation on Human Blood

Mohammed Ali Haimid, Ali A. S. Marouf, M. D. Abdalla

Asian Journal of Research and Reviews in Physics, Page 1-7
DOI: 10.9734/ajr2p/2019/v2i130087

Laser irradiation has biostimulating effect in various cell types low power laser radiation is used clinically for skin and vascular disorders.

Aims: To investigate the effect of (He-Ne) laser (λ= 632nm, power=1mW) on human whole blood, after irradiated to different times from 10 min to 50 min.

Study Design:  Human Whole Blood Irradiated to (He-Ne) laser(λ= 632nm, power=1mW). 

Place and Duration of Study: Soba Hospital, Khartoum- Sudan, Institute of Laser, Sudan University of science and technology (SUST), February 2018.

Methodology: Blood samples were taken from healthy volunteers; blood sample irradiated to (He-Ne) laser and control compared; FTIR and UV-Vis spectrophotometer were used to study laser radiation effect

Results: FTIR spectra and UV-vis absorption spectra of blood samples are compared before and after irradiated to He-Ne laser shows increases absorption for 10, and 40 min  but it decreases as the exposure time at 30,20 and 50 minutes. This fluctuation of light absorption is known as a biphasic response.

FTIR spectra of non exposed blood showed the peaks due to O-H (free group), C=O (amide I group), N=O (nitro group), and C-H (aromatic group). N-H (Amino acid (amide II). For all exposure time He-Ne laser (λ= 632nm, power=1mW) irradiation, showed significant changes. Increased in transmittance at different exposure time for all groups (C=O, O-H, N=O, C-O & C-H, N-H) and indicates significant decreasing in their concentration.

Conclusion: The laser radiation causes changes in the structure and conformational changes in the polypeptide and absorption of blood samples decreased due to increasing ligand electronegativity.

Open Access Original Research Article

Theoretical Verification of the Formula of Charge Function in Time of Capacitor (q = c*v) for Few Cases of Excitation Voltage

Shantanu Das

Asian Journal of Research and Reviews in Physics, Page 1-17
DOI: 10.9734/ajr2p/2019/v2i130091

We have a developed and derived a formula for capacitor i.e. charge as a function of time, which is convolution operation of time varying capacity function and time-varying voltage function. This is different to the usual and conventional way of writing capacitance multiplied by voltage to get charge stored in a capacitor. This new deliberation with convolution operation works well for classical capacitors (i.e. ideal loss less capacitors), that is of a constant capacity at all frequencies, and also for a time varying capacity function given by decaying power-law: that gives the formation of a fractional capacitor. In this paper, we use this developed new charge storage expression and apply to various types of inputs excitation voltage-sinusoidal, step, ramp voltage and then analyze and interpret the results for charge stored, the current expressions, the loss-tangent and the memory effects. With this new formulation, we also evaluate impedance function of a classical capacitor as well as a fractional capacitor, and also elaborate on the Nyquist’s diagram, that is employed to study various dielectric materials via impedance spectroscopy. This new approach of charge storage concept is yet to be practically as well as theoretically applied-though some initial work has started. This paper gives a theoretical validity test i.e. analytically obtained in several applications for this new formulation, of charge storage formula. This paper will be useful in various super-capacitor studies, dielectric relaxation experiments, and impedance spectroscopy for various material developments for electrical energy storage missions; however, this concept is yet to be used to its full potential.