Volume 5 Issue 1

Authors: Fayez Mahamoud El-Hossary; Sayed Mohammed Khalil; Magdy Abdel Wahab Kassem; Medhat Abd EL Lateef; Doha Saber Mohamed; Khaled Lotfy

Abstract: Nickel-titanium (Ni-Ti) shape memory alloys (SMAs) are attractive materials for orthopedic and dental implants, due to its two intrinsic properties including shape memory effect (SME) and superelasticity (SE), which may not be found in other commonly-used surgical metals. Possible Ni ion release, however, hampers their medical applications, particularly in orthopedic implants where fretting is always expected at the articulating surface. Inductively coupled radio frequency plasma (ICRFP) was employed to alter the surface of equiatomic Ni-Ti discs in order to create a barrier to out-diffusion of Ni ions from the bulk material. The ICRFP experiments were carried out with nitrogen, which promoted the formation of a titanium nitride layer on the surface of the Ni-Ti samples. The present paper explores the biocompatibility and performance of the ICRFP treated and untreated Ni-Ti samples. The results confirm that nitrogen plasma modified Ni-Ti alloys are potentially suitable materials for orthopedics without inducing harmful biological effects.

Keywords: Nickel-Titanium (Ni-Ti); Superelasticity (SE); Shape Memory Effect (SME); Inductively Coupled Radio Frequency Plasma (ICRFP); Biocompatibility; Corrosion Resistance


Authors: Yuji Kajiyama

Abstract: In this paper, we study Tarzan’s dilemma of elliptic and cycloidal motion. We give the relation between the flying distance and the launching angle of these two different motions, and perform numerical calculation to find the launching angle which maximizes the flying distance. This study will be helpful for understanding elementary mechanics for students.

Keywords: Classical Mechanics; Physics Education


Authors: Gökhan Sahin

Abstract: The effect of wavelength on the photocurrent and photovoltage of a vertical parallel junction solar cell under steady state condition was theoretically analyzed. Based on the diffusion equation, the excess minority carrier’s density is expressed; both photocurrent density and photovoltage determine the junction recombination velocity and the wavelengths. The excess minority carrier density, the photocurrent density, and the photovoltage were calculated and plotted. The objective of this work is to show the effects of solar cell junction recombination velocity and the wavelengths on these electrical parameters. We have shown the effect of wavelength on initiating the short-circuit (Sfsc) and limited the open circuit (Sfoc) of the solar cell through the junction recombination velocity. The determination of Sfoc obtained from the curve of photovoltage versus Sf, and the determination of Sfsc is through from the curve of the photocurrent density according to Sf.

Keywords: Vertical Parallel Solar Cell; Recombination Velocity; Photocurrent; Photovoltage


Authors: Gökhan Sahin

Abstract: Temperature is a very important parameter that is often overlooked in the behavior of solar cells. This study presents the influence of temperature on the electrical parameters of a bifacial silicon solar cell under frequency modulation. Based on the equation of the continuity of the carriers, the expression of the density of the minority charge carriers, the photocurrent and the photo-voltage were determined. For all these temperatures the effect is interpreted as a function of frequency modulation. The aim of this work is to study the evolution of this density depending on temperature and its distribution in angular frequency and the junction recombination velocity in the bases for different values of the temperature.

Keywords: Photovoltaic; Junction Recombination Velocity; Angular Frequency; Series and Shunt Resistance; Temperature


Authors: Gökhan ŞAHİN

Abstract: This study investigates the study of the photo thermal response of a junction vertical parallel silicon solar cell illuminated by a multispectral light for a constant modulated frequency. Solving the continuity equation for minority carriers in the base of the solar cell resulting in the terms of the heat equations in the presence of an optical source. The density of minority carriers in excess, the amplitude of the variation of temperature and the heat flux density were studied and analyzed for different angular pulses and junction recombination velocity. It also deals use of a new approach that involves parameter of the solar cell. Based on the normalized carrier’s density, we calculate and plot the temperature and heat flux variation versus base depth, angular frequency, incidence angle and wavelength for different operating conditions.

Keywords: Vertical Parallel Junction Silicon Solar Cell; Temperature; Heat Flux


Authors: J. O. Jonson

Abstract: The competence of the basically electrostatic Coulomb’s Law has historically been assumed to be restricted to pure electrostatics. As soon as electric charges were studied in motion, new sets of laws were introduced to explain the electromagnetic forces that are impelled by the motion. Among these new laws are Neumann’s law of induction, Grassmann’s force law, Lorentz’ force law, and Ampère’s force law. Furthermore, the difficulties in explaining the nature of light have given rise to the so-called wave-particle paradox. 1997 was the first year of the public circulation of research results that succeeded in showing that the basic force behind cases involving electricity or, more precisely, electromagnetism, can be derived from electrostatics. The aim of this article is to unify the results of existing theoretical research that discusses problems inherent within the prevailing standpoint on electromagnetism. In this paper, the conflict between the Lorentz Force Law and Ampère’s Law is explored. Simultaneously, an alternative based strictly on electrostatics is closely examined. The very limited interest in this field of research, however, makes the amount of existing papers rather limited. The present study’s new intervention is as follows: The so-called Ampère forces between collinear currents, as in Ampère’s bridge and in exploding wires, have been explained to be due to electrostatics, provided that the propagation delay dependant on the motion of charges is correctly taken into account. The Lorentz Force Law fails in this case. Additionally, electromagnetic induction can be explained by applying electrostatics, whereas the induction law fails. Light on the orbit electrons in the atoms involved in excitation and de-excitation of states can be explained using Coulomb’s law (this has been widely disputed within science). The appearance of light at an atom hit by electromagnetic radiation can be shown to constitute a case of electromagnetic induction. The present study’s conclusion is therefore that Coulomb’s law is the only necessary force law within electromagnetism.

Keywords: Coulomb’s Law; Ampere’s Law; Ampere’s Bridge; Grassmann’s Law; Lorentz’ Force Law; Neumann’s Law; Lenz’ Law; Electromagnetic Radiation; Graneau’s Exploding Wires; Propagation Delay; Sagnac Effect; Special Relativity Theory