<abstract xmlns="http://www.w3.org/1999/xhtml"> The Schrödinger equation with pseudo-Gaussian potential is investigated. The pseudo-Gaussian potential can be written as an infinite power series. Technically, by an ansatz to the wave-functions, exact solutions can be found by analytic approach [12]. However, to calculate the solutions for each state, a condition that will stop the series has to be introduced. In this way the calculated energy values may suffer modifications by imposing the convergence of series. Our presentation, based on numerical methods, is to compare the results with those obtained in the analytic case and to determine if the results are stable under different stopping conditions. </abstract>

West University of Timişoara 300223 V. Pârvan Ave 4, Timişoara, Romania

Politehnica University of Timişoara, 300223 Traian Lalescu 2, Timişoara Romania

A Numerical Approach for the Solution of Schrödinger Equation With Pseudo-Gaussian Potentials

<abstract xmlns="http://www.w3.org/1999/xhtml"> We consider the Schrödinger equation with pseudo-Gaussian potential and point out that it is basically made up by a term representing the harmonic oscillator potential and an additional term, which is actually a power series that converges rapidly. Based on this observation the system can be considered as a perturbation of harmonic oscillator. The perturbation method is used to approximate the energy levels of pseudo- Gaussian oscillator. The results are compared with those obtained in the analytic and numeric case. </abstract>

Approximate Solution of Schrödinger Equation with Pseudo-Gaussian Potential Viewed as a Perturbation

<abstract xmlns="http://www.w3.org/1999/xhtml"> Two samples of manganese ferrite powder were obtained by the calcination method (sample A) and hydrothermal method (sample B). The crystal structure of the samples has been determined using X-ray diffraction analysis (XRD). The results shown that the sample A has three phases (FeMnO3, Mn2O3 and Fe2O3) and the prevailing phase is FeMnO3 with perovskite structure and the sample B has only a single phase (MnFe2O4). The grain morphology was analyzed by scanning electron microscopy (SEM) and the compositional analysis was done by energy dispersive spectroscopy (EDAX). Measurements of the frequency (f) and temperature (T) dependent complex impedance, Z(f, T) = Z’(f, T) - i Z’’(f, T) of the samples over the frequency range 20 Hz - 2 MHz, at various temperature values from 300C to 1100C are presented. From these measurements, we have shown that the temperature dependence of the relaxation time is of Arhenius type, which suggests that the conduction process is thermally activated. The values obtained for the activation energy Ea, are: 16meV (sample A) and 147.65meV (sample B). Applying complex impedance spectroscopy technique, the obtained results shows the shape of a single semicircle at each temperature over the measurement range, meaning that the electrical process obeys to a single relaxation mechanism. The impedance and related parameters of the electrical equivalent circuit depend on the temperature and the microstructure of samples. The resistive and capacitive properties of the investigated samples are dominated with the conduction and relaxation processes associated with the grain boundaries mechanism.. </abstract>

West University of Timisoara, Faculty of Physics, Bd.V. Pârvan, No. 4, 300223 Timisoara, Romania

West University of Timisoara, Faculty of Physics, Bd.V. Parvan, No. 4, 300223 Timisoara, Romania

West University of Timisoara, Faculty of Physics, Bd.V. Parvan, No. 4, 300223 Timisoara, Romania,

National Institutes for Research and Development in Electrochemistry and Condensed Matter, 300569 Timisoara, Romania

Complex Impedance of Manganese Ferrite Powders Obtained by Two Different Methods

<abstract xmlns="http://www.w3.org/1999/xhtml"> In this study, time dependent three-dimensional numerical simulations were carried out using the STHAMAS3D software in order to understand the effects of forced convection induced by mechanical stirring of the melt, on the crucible dissolution rate and on the impurities distribution in multicrystalline silicon (mc-Si) melt for different values of the diffusion coefficient.Numerical simulations were performed on a pilot scale furnace with crucible dimensions of 38x38x40cm3. The computational domain used for the local 3D-simulations consists of melt and crystal.The dissolution rate was estimated from the total mass of impurities that was found in the silicon melt after a certain period of time. The obtained results show that enhanced convection produced by a mechanical stirrer leads to a significant increase of the dissolution rate and also to a uniform distribution of impurities in the melt.</abstract>

Faculty of Physics, West University of Timisoara, Bd. V. Pârvan 4, 300223 Timisoara, Romania

Faculty of Physics, West University of Timisoara, Bd. V. Pârvan 4, 300223Timisoara, Romania

Influence of Mechanical Stirring on the Crucible Dissolution Rate and Impurities Distribution in Directional Solidification of Multicrystalline Silicon

<abstract xmlns="http://www.w3.org/1999/xhtml"> A laboratory - made nonthermal plasma generator is presented. It has a diameter of 0.020 m and length of 0.155 m and contains two electrodes. The first electrode is a 2% Th-W alloy, 0.002 m in diameter bar, centred inside the generator’s body by means of a four channel teflon piece; the other three channels, 0.003 m in diameter, are used for Ar supply. The second electrode is a nozzle of 0.002 m - 0.008 m diameter and 0.005m length. A ~500 kV/m electric field is generated between the two electrodes by a high frequency source (13.56 MHz ±5%), equipped with a OT-1000 (Tungsram) power triode. For Ar flows ranging from 0.00008 m3/s to 0.00056 m3/s, a plasma jet of length not exceeding 0.015 m and temperature below 315 K is obtained. Anthurium andraeanumis sample , blood matrix, human hair and textile fibers may be introduced in the plasma jet. For time periods of 30 s and 60 s, various effects like, cell detexturization, fast blood coagulation or textile fiber or hair cleaning and smoothing are obtained. These effects are presented and discussed in the paper.</abstract>

Faculty of Physics, West University of Timisoara, 300223-Timisoara

Joint Institute for Nuclear Research, Dubna, 141980 Moscow Region, Russian Federation

Horia Hulubei National Institute for Physics and Nuclear Engineering, Bucharest, Romania

Nonthermal Argon Plasma Generator and Some Potential Applications

<abstract xmlns="http://www.w3.org/1999/xhtml"> Two samples of NaTaO3 perovskite materials were prepared by the standard hydrothermal method at the same reaction temperature (600 °C) but with different sintering times: 6 hours for sample S1 and 12 hours for sample S2.Using X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (Ta2O5 and the prevailing phase NaTaO3). The scanning electron microscopy analysis (SEM), shows that the grains are connected each other in agglomerated clusters of size about few hundred nanometers.The frequency (f) dependencies of complex impedance, Z(f) = Z’(f) - i Z’’(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z’ of the complex impedance decreases with increasing frequency and the imaginary component Z’’ has two maximum corresponding to two relaxation processes.The results obtained from the complex impedance spectroscopy, Z’’(Z’) showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.</abstract>

”Politehnica” University, Str. P-ta Victoriei No. 2, RO-300006 Timisoara, Romania

National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Str. Plautius Andronescu Nr. 1, RO-300224 Timisoara, Romania

West University of Timisoara, Faculty of Physics, Str. V. Pârvan Nr. 4, RO-300223 Timisoara, Romania

Electric Properties of NaTaO3 Obtained by Hydrothermal Method

<abstract xmlns="http://www.w3.org/1999/xhtml"> The construction of a solid state device-based pyranometer designated to broadband irradiance measurements is presented in this paper. The device is built on the physical basis that the temperature difference between two bodies of identical shape and external surface area, identically exposed to the incident radiation, but having different absorption and heat transfer coefficients (e.g. one body is painted white and the other is painted black), is proportional to the incident irradiance. This proportionality may be put in evidence if the two bodies consisting of identical arrays of correspondingly painted semiconductor diodes, due to the thermal behaviour of their p-n junction. It is theoretically predicted and experimentally confirmed that the voltage drop across a diode passed through a constant forward current linearly decreases with the temperature of the junction. In other words, a signal proportional to the irradiance of the light source may be obtained via conventional analog electronics. The calibration of the apparatus, as performed by means of a professional device (LP PYRA 03), indicates a good linearity.</abstract>

A Solid State Pyranometer

<abstract xmlns="http://www.w3.org/1999/xhtml"> Climate variability is a hot topic not only for scientists and policy-makers, but also for each and every one of us. The anthropogenic activities are considered to be responsible for most climate change, however there are large uncertainties about the magnitude of effects of solar variability and other extraterrestrial influences, such as galactic cosmic rays on terrestrial climate. Clouds play an important role due to feedbacks of the radiation budget: variation of cloud cover/composition affects climate, which, in turn, affects cloud cover via atmospheric dynamics and sea temperature variations. Cloud formation and evolution are still under scientific scrutiny, since their microphysics is still not understood. Besides atmospheric dynamics and other internal climatic parameters, extraterrestrial sources of cloud cover variation are considered. One of these is the solar wind, whose effect on cloud cover might be modulated by the global atmospheric electrical circuit. Clouds height and composition, their seasonal variation and latitudinal distribution should be considered when trying to identify possible mechanisms by which solar energy is transferred to clouds. The influence of the solar wind on cloud formation can be assessed also through the ap index - the geomagnetic storm index, which can be readily connected with interplanetary magnetic field, IMF structure. This paper proposes to assess the possible relationship between both cloud cover and solar wind proxies, as the ap index, function of cloud height and composition and also through seasonal studies. The data covers almost three solar cycles (1984-2009). Mechanisms are looked for by investigating observed trends or correlation at local/seasonal scale</abstract>

University of Galati, Faculty of Sciences and Environment, Chemistry, Physics and Environment Department, 111 Domneasca Street, 800201 Galati, Romania

Dunarea de Jos University of Galati, Faculty of Sciences and Environment, Chemistry, Physics and Environment Department, 111 Domneasca Street, 800201 Galati, Romania

Clouds and the Near-Earth Environment: Possible Links

<abstract xmlns="http://www.w3.org/1999/xhtml"> There are many electromagnetic field (EMF) sources nowadays acting simultaneously, especially in urban areas, making the theoretical estimation of electromagnetic power at ground level very difficult. This paper reports on EMF maps built with measurements collected in Timisoara, at various radiofrequencies. A grid of 15×15 squares was built (approximate resolution 400m x 400m) and measurements of the average and maximum values of the electric field E, magnetic field H and total power density S at 0.9, 1.8 and 2.4 GHz were collected in every node of the grid. Positions of the nodes in terms of latitude and longitude were also collected. Maps were built presenting the spatial distribution of the measured quantities over Timisoara. Potential influences of EMF on public health are discussed.</abstract>

Faculty of Physics, West University of Timisoara, Bd. V. Pârvan nr. 4, 300223, Timisoara, Romania

Faculty of Physics, West University of Timisoara, Bd. V. Parvan nr. 4, 300223, Timisoara, Romania

Radiofrequency Electromagnetic Field Map of Timisoara

<abstract xmlns="http://www.w3.org/1999/xhtml"> The complex magnetic susceptibility χ(f) = χ′(f) - i χ″(f), of a ferrofluid sample with magnetite particles dispersed in kerosene and stabilized with oleic acid, over the range 0.1 GHz to 6 GHz, was determined. The initial sample has been successively diluted with kerosene (with a dilution rate of 2/3), thus obtaining further three samples. Using the complex magnetic susceptibility measurements of each sample, the frequency field and particle concentration dependencies of the heating rate of the ferrofluid samples, were analyzed. The results show the possibility of using the heating rate of ferrofluid samples with different particle concentrations, in hyperthermia applications.</abstract>

West University of Timisoara, Faculty of Physics, B-dul V. Pârvan, no. 4, 1900 Timisoara, Romania

Department of Electronic and Electrical Engineering, Trinity College, Dublin 2, Ireland

West University of Timisoara, Faculty of Physics, B-dul V. Parvan, no. 4, 1900 Timisoara, Romania

The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia

<abstract xmlns="http://www.w3.org/1999/xhtml"> We consider an application of the tetrad formalism introduced by Cardall et al. [Phys. Rev. D 88 (2013) 023011] to the problem of a rigidly rotating relativistic gas in thermal equilibrium and discuss the possible applications of this formalism to rel- ativistic lattice Boltzmann simulations. We present in detail the transformation to the comoving frame, the choice of tetrad, as well as the explicit calculation and analysis of the components of the equilibrium particle ow four-vector and of the equilibrium stress-energy tensor.</abstract>

Relativistic Rotating Boltzmann Gas Using the Tetrad Formalism

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Annals of West University of Timisoara - Physics

 The first issue of the Annals of the West University of Timisoara, was published in 1963 under the name of Mathematical and Physical Sciences Series, and it was issued on yearly basis ever since. Since 2002 the journal is being published in a new graphical format, as the Annals of the West University of Timisoara, Physics Series. The journal welcomes manuscripts presenting information not previously published in journals, in the areas of Materials Science, Theoretical and Computational Physics, Applied Physics, Medical Physics. The submitted manuscripts are peer-reviewed, insuring a high standard of scientific quality to the accepted articles.  Why subscribe and read  The journal publishes current and original research results in the fields of Materials Science, Theoretical and Computational Physics, Applied Physics, Medical Physics.  Why submit   Fast review and publication process  Fast and constructive peer review   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 