Open Access Short communication

Effect of Annealing Process on Porous Aluminium Filled with Graphite

Amel Lafi Al-Otaibi, Muneera Abdullah Al-messiere, Taher Ghrib

Physical Science International Journal, Page 1040-1049
DOI: 10.9734/PSIJ/2014/9648

Thermal properties of porous thin films formed by anodization of thin aluminum films in sulfuric acid. The obtained pores at the surface are filled by sprayed graphite which the role is to improving its optical and thermal absorption giving a structure of an assembly of three different media such as graphite/(Porous aluminium layer filled with graphite)/(Al sample). The realized structure is annealed in temperature range varying from the room temperature to 650ºC for various durations. Thermal properties of the realized structure was studied by Photothermal Deflection (PTD) Technique and correlated to the microstructure evolution. It was found that this structure is characterised by thermal conductivity which, conversely to thermal diffusivity, increases with the heating duration and temperature in the furnace and can be used in solar energy field.

 

Open Access Minireview Article

Entropy and Temperature from Entangled Space and Time

Young S. Kim, Marilyn E. Noz

Physical Science International Journal, Page 1015-1039
DOI: 10.9734/PSIJ/2014/10336

Two coupled oscillators provide a mathematical instrument for solving many problems in modern physics, including squeezed states of light and Lorentz transformations of quantum bound states. The concept of entanglement can also be studied within this mathematical framework. For the system of two entangled photons, it is of interest to study what happens to the remaining photon if the other photon is not observed. It is pointed out that this problem is an issue of Feynman’s rest of the universe. For quantum bound-state problems, it is pointed out the longitudinal and time-like coordinates become entangled when the system becomes boosted. Since time-like oscillations are not observed, the problem is exactly like the two-photon system where one of the photons is not observed. While the hadron is a quantum bound state of quarks, it appears quite differently when it moves rapidly than when it moves slowly. For slow hadrons, Gell-Mann’s quark model is applicable, while Feynman’s parton model is applicable to hadrons with their speeds close to that of light. While observing the temperature dependence of the speed, it is possible to explain the quark-to-parton transition as a phase transition.

Open Access Original Research Article

The Equation of State for Non-ideal Quark Gluon Plasma

N. M. El Naggar, L. I. Abou Salem, A. G. Shalaby, M. A. Bourham

Physical Science International Journal, Page 912-929
DOI: 10.9734/PSIJ/2014/10296

The mass spectra of quarkonium systems at T= 0 are analyzed by solving the non-relativistic radial wave equation using the internal energy potential. The QGP matter is studied through the dissociations of quarkonium states. A modified form of the internal energy potential function is used to determine the EoS at different number of quark flavors by using Mayer's cluster expansion theory and phenomenological thermodynamic model. The thermodynamic model gives a good agreement with the lattice results rather than Mayer’s cluster expansion theory. One can conclude that, the Mayer’s cluster expansion theory may be more suitable to study a weakly coupled plasma while, the QGP may be considered as a strongly interacting plasma.

 

Open Access Original Research Article

Distributions of Electron Density and Electron Temperature in Magnetized DC Discharge

Ahmed Rida Galaly

Physical Science International Journal, Page 930-939
DOI: 10.9734/PSIJ/2014/9604

The distribution of electron temperature Te and density Ne in a dc glow discharge that is created by a pair of circular parallel electrodes is studied using double probes. The measurement are carried out for the following two modes: in the presence and in the absence of the magnetic field. In the absence of the magnetic field, for the radial distribution, temperatures have same values with small variation, in the same discharge region [cathode fall or negative glow or positive column region], except at the edge. For the axial distribution, the distribution profiles of Te shows that Te is decreased, and Ne continues to increase toward the anode. In the presence of the magnetic field, the radial distribution of the electron density has its highest value at the edge where the magnetic field is maximum. The electron temperature changes very little. The density begins to increases also from the cathode fall region, at the edge, to the negative glow region and then it decreases sharply at the positive column region. The plasma is very intense in the cathode fall region (very thin bright ring) and very brighter and sharp in the negative glow region (extends several mm from the cathode fall region). But in the positive column, the density begins to decrease.

 

Open Access Original Research Article

Inhibition of Pitting Corrosion of Some Austenitic Stainless Steel Samples in 2.5 M Nacl Solution by 3- Amino-1, 2, 4-Triazole

Magdy A. M. Ibrahim, S. S. Abd El Rehim, M. M. Hamza

Physical Science International Journal, Page 940-953
DOI: 10.9734/PSIJ/2014/10528

The effect of addition of 3-AMINO-1,2,4-TRIAZOLE (ATA) on general and pitting corrosion of three Egyptian austenitic stainless steel samples, namely SS 304L (0.09 Mo), SS 304H (0.43 Mo) and SS 304H (1.15 Mo) in aerated 2.5 M NaCl solution was investigated. The measurements were carried out using potentiodynamic polarization and the Tafel lines methods. The influence of temperature on the inhibition properties of ATA was investigated. The results indicate that ATA is a good inhibitor for the samples under investigation in 2.5 M NaCl solutions. In addition, the inhibition efficiency η% increases with the inhibitor concentration while it decreases with increasing temperature. Moreover, addition of ATA to 2.5 M NaCl solution leads to a shift of the pitting potential towards the noble direction accounting for increased resistance to pitting attack. The inhibitive properties of the ATA were explained on the bases of its adsorption on the stainless steel samples and formation of adsorbed barrier layer, which resist the penetration power of Cl- ion and consequently decreases the rate of pitting corrosion. The adsorption of the inhibitor obeys a Temkin adsorption isotherm. Examination of polarization curves indicates that ATA acts as a mixed-type inhibitor.

 

Open Access Original Research Article

Synchronization of Sources of Radiation with the Help of Tunneling

Yuriy N. Zayko

Physical Science International Journal, Page 954-961
DOI: 10.9734/PSIJ/2014/9239

This article is devoted to investigation of the mechanism of synchronization of the sources of electromagnetic radiation due to tunneling between two vacuums of the Maxwell-Einstein equations. The implementation of this mechanism permits to avoid the hypothesis of the inflation stage of the Universe expansion which is adopted for the explanation of relict radiation isotropy.

 

Open Access Original Research Article

Random Telegraph Signals Generated in Transistors Due to Gamma Ray Irradiation: Online Study of the Device Characteristics

P. Mohamed Aslam, M. M. Musthafa, Biju P. Thomas, K. R. Rajesh

Physical Science International Journal, Page 962-972
DOI: 10.9734/PSIJ/2014/8904

Commercial transistors have been irradiated with photon of 6 MeV and15 MeV energies and the device characteristics were studied during irradiation process. Along with expected reduction in current gain due to charge carrier trapping and other effects, considerable amount of noise signals resulting from modulation of RTS also have been observed which was seen to be died out within 30 seconds after the irradiation. The possible source and the nature of noise signals were analyzed. The similarities between the low varying random signals with 1/f noise are discussed.  

 

Open Access Original Research Article

Numerical Simulation of Spin Glass State in Diluted Magnetic Materials Using Ising Spin Model in 2D with Distance Dependent Interactions

Habte Dulla Berry, Pooran Singh

Physical Science International Journal, Page 973-979
DOI: 10.9734/PSIJ/2014/9933

In the present paper, existence of spin glass state using Ising spin model with Edwards-Anderson type of interactions has been investigated by employing numerical simulation (Monte Carlo) technique. The study shows a phase transition from paramagnetic state to spin glass state when far apart spins are included in addition to nearest neighbor ones using power law decaying interactions. 

 

Open Access Original Research Article

Numerical Simulation Studies on Piezoelectric Properties of Lead Zirconium Titanate

N. Z. Elsayed

Physical Science International Journal, Page 980-987
DOI: 10.9734/PSIJ/2014/10723

Structural properties of the compounds were examined using an X-ray diffraction (XRD) technique to confirm the formation of phase at different temperature. The electrical current response for equivalent circuit of PZT-5A, resonant frequencies, antiresonant frequencies and mechanical quality factor were studied by numerical simulation and compared with experimental results. The dielectric properties of PZT-5A ceramics in the temperature range 50 -200ºC were measured. The effect of grain size of the PZT-5A on the dielectric constant and dielectric loss were investigated. As the grain size increased, the maximum dielectric constant increased. The dielectric study with frequency at different temperature in the frequency range 1 to 5 MHz shows that dielectric constant decreases with increasing frequency. Loss factor does not vary with frequency but it becomes independent of higher frequency range.

 

Open Access Original Research Article

Alternating Current Instability of Conduction-Cooled High-Tc Superconductors and Superconducting Tapes

V. R. Romanovskii, K. Watanabe, A. M. Arkharov, S. Awaji, N. A. Lavrov, V. K. Ozhogina

Physical Science International Journal, Page 988-1014
DOI: 10.9734/PSIJ/2014/11069

The AC current instability mechanisms are investigated in high-Tc superconductor and superconducting tape at conduction-cooled conditions when the electric field and applied current may essentially exceed the critical values of a superconductor. It is shown that there exist the characteristic times defining the corresponding time windows that are the basis of the existence of the stable AC regimes despite the high values of the induced electric field and the temperature of a superconductor. It is proved that these values are higher than the corresponding values of the electric field and the temperature before the thermal runaway. These states may be defined as stable overloaded regimes. Therefore, high-Tc superconducting magnets are possible to operate stably at AC overloaded regimes and the conduction-cooled conditions, which will be characterized by very high AC losses.