Current issue of "International Review of Physics (IREPHY)"

International Review of
Physics
(IREPHY)
February 2014 (Vol. 8 N. 1)

of IREPHY:

A Studying of Some Physical and Mechanical Properties for Hybrid Particular Composites Polyester

by Kareem A. Jasim, R. S. Al-Khafaji

Abstract - Fillers play a major role in determination of the properties and behavior of product composite. The work concerned to prepare samples of (Black carbon – Boron) reinforced unsaturated polyester hybrid composites, with different additive ratios as (0%,2%,4%,6%) of volume fractions. Thermal conductivity, electrical conductivity, modulus of elasticity , Brinell hardness , and surface roughness are investigated .The results observed marked decreasing of thermal conductivity values (4.170-0.787 W / m k) and surface roughness (1.976-0.871µm)with volume fraction of Boron(0%-6%) as reinforced fillers .On the other hand ,it noticed that electrical conductivity values (0.0219-0.0255 S/m), modulus of elasticity(18.908-19.537 MPa) , Brinell hardness (5.778-5.971 MPa) are increased with volume fraction of Boron(0%-6%) as reinforced fillers.

Keywords: Composite, Carbon, Boron, Polyester Hybrid Composite, Thermal Conductivity, Electrical Conductivity, Modulus of Elasticity, Brinell Hardness, Surface Roughness.

Numerical Tribute to Achievements of Euler

by Carlos Figueroa, Lamberto Castro, Julio C. Campos

Abstract - This paper aims to make a tribute to one of the world's brightest personalities, the mathematical physicist Leonhard Euler (1707-1783). Our purpose is to expose, in a concise and entertaining way by utilizing modern computational techniques, a better understanding of the influence of Euler; also, to establish the remarkable significance in the history of science. A first analysis was done with the series that defines Euler and Bernoulli numbers and polynomials of Bernoulli and Euler; an additional result is the characterization of the functions that lead to the Euler-Mascheroni constant. In hydrodynamics it is also feasible to evaluate graphically the connection between sizes in diameter and the exit angle of the height of Euler for turbo-machines. In differential equations of Cauchy-Euler solutions in the cases of distinct real roots and complex roots are generated. Furthermore we report the generation of the Fourier series and the Fourier transform calculated by using direct Matlab commands. In calculus of variations, it is conceivable to obtain plots from a problem of the Euler Lagrange equations. Finally, Euler totient function is graphically analyzed. We seek the following benefits: The association between Euler numbers and generating functions is more effectively understood, also the nature of the Euler constant and the Euler function The Fourier transform is more comprehensible; also, it can be established that Matlab is an alternative way to study the conceptual development of achievements of physics and mathematics. We show that the abundance of Euler work and the history of mathematics, acquire better knowledge with the application of numerical tools.

Keywords: Calculus of Variations, Euler Height, Euler Mascheroni Constant, Euler Totient Function, Fourier Series, Taylor Polynomials.

Binder Cumulant for Bond Diluted Ising Model

by I. Zergoug, R. Bouamrane

Abstract - The fourth order Binder cumulant U and the critical Binder cumulant U* of bond-diluted Ising model on a square lattice are studied using Monte Carlo techniques. The values of the transition temperature Tc obtained from U* for different probabilities of bond dilution p are discussed. When p is no too large (p<0.35), Tc decreases when p increases and U* also decreases. For p>0.35, things are not so clear and our results show that the determination of Tc from U is questionable.

Keywords: Diluted Ising Model, Binder Cumulant, Monte Carlo Simulation.

Effect of Laser Pulse Energy and Vacuum Pressure on the Cu Laser Induced Plasma Plume Length

by Kadhim A. Aadim, Ali A-K. Hussain, Mohammed R. Abdulameer

Abstract - In this work, copper laser induced plasma plume length werecalculated by CCD camera photos calculations. TheCu laser induced plasma pictures were taken by using CCD camera.Cu plasma plume length was investigated by varying the laser induced plasma parameters in the experiment such as laser pulse energy and vacuum pressure.Pulsed Nd: YAGlaser 7ns pulse duration and 1Hz pulse repetition rate was used to ablate the Cutarget under vacuum in stainless steel vessel. The effects of the laser pulse energy and vacuum pressure on the Cu plasma plume length was studied by calculating the plasma plume length from the laser induced plasma picture taken by CCD camera. It is found that the plasma plume length depends strongly on the laser ablation conditions such as laser pulse energy and vacuum pressure, it is directly proportional to laser pulse energy and inversely proportional to the vacuum pressure.

Keywords: CCD Camera, Laser Induced Plasma, Plasma Plume Length, Pulsed Laser Ablation, Vacuum.

Dielectric and Microwave Properties of Natural Rubber Based Composites Containing Fullerene Black

by Omar A. Al-Hartomy, Ahmed Al-Ghamdi, Nikolay Dishovsky, Desislava Slavcheva, Vladimir Iliev, Farid El-Tantawy

Abstract - It is expected that filling a rubber with a small amount of fullerene could lead to a new set of properties, bringing to the composite advantages over the rubbers in use. In the present work, the dielectric and microwave properties of natural rubber (SMR10) based composites containing various concentration of fullerene black (0-7,5 phr), rich in fullerenes (7,5%) were investigated in the 1-12 GHz frequency range. It has been established that within the range used for the experiments the increasing frequency and fullerene filler amount lead to an increase in the values of relative dielectric permittivity, dielectric loss angle tangent, reflection coefficient and attenuation of electromagnetic waves, while the values for shielding effectiveness get lower. That is due to the fact that under the experimental conditions the change in the reflection coefficient is greater than that in the attenuation of electromagnetic waves. The dielectric properties of the composites (especially the dielectric loss angle tangent) are more affected by fullerene black filler than their microwave properties. Further change in the properties could also occur at higher concentrations of fullerene black but the cost of rubber compound would be much higher.

Keywords: Natural Rubber, Nanocomposites, Dielectric Properties, Microwave Properties.