Volume 59, Number 78, 2014
Mathematical and Theoretical Physics
Symmetry Reductions and New Wave Solutions for the 2D BurgersKortewegde Vries Equation Rodica Cimpoiasu Romanian Journal of Physics 59,
617624 (2014)
This paper is trying to clarify recent published results related to a generalized version of $2D$ BurgersKdV equation. The generalization consists in considering a nonlinearity of the form $u^n$ as coefficient of the second derivative $u_{xx}$ . The claim was that the Lie algebra does not depend on $n$. We show that different algebras correspond to $n = 1$ and $n \ge 2$. One proves that the correct algebra for the case $n = 1$ depends on four constant parameters and two independent functions. By using similarity reduction procedure, new pointlike symmetries and invariant wave solutions of the equation are generated.
A Numerical Solution of the UrysohnType Fredholm Integral Equations A. Jafarian, S.A. Measoomy, Alireza K. Golmankhaneh, D. Baleanu Romanian Journal of Physics 59,
625635 (2014)
In the present paper, a combination of the Bernstein polynomials and artificial neural networks (ANNs) is presented for solving the nonlinear Urysohn equation. These polynomials are utilized to reduce the solution of the given problem to the solution of a system of nonlinear algebraic equations. The remaining set of nonlinear equations is solved numerically by using the ANNs approach to yield truncated Bernstein series coefficients of the solution function. Several illustrative examples with numerical simulations are provided to support the theoretical claims.
The Modified Fractional SubEquation Method and Its Applications to Nonlinear Fractional Partial Differential Equations Gang Wei Wang, Tian Zhou Xu Romanian Journal of Physics 59,
636645 (2014)
In this paper, we propose a modified fractional subequation method to solve fractional partial differential equations. By using of this method, the spacetime fractional generalized WhithamBroerKaup equations and time fractional biological population equation are successfully solved. As a result, three types of exact and explicit solutions are obtained.
A New Generalized LaguerreGauss Collocation Scheme for Numerical Solution of Generalized Fractional Pantograph Equations A.H. Bhrawy, A.A. AlZahrani, Y.A. Alhamed, D. Baleanu Romanian Journal of Physics 59,
646657 (2014)
The manuscript is concerned with a generalization of the fractional pantograph equation which contains a linear functional argument. This type of equation has applications in many branches of physics and engineering. A new spectral collocation scheme is investigated to obtain a numerical solution of this equation with variable coefficients on a semiinfinite domain. This method is based upon the generalized Laguerre polynomials and Gauss quadrature integration. This scheme reduces solving the generalized fractional pantograph equation to a system of algebraic equations. Numerical results indicating the high accuracy and effectiveness of this algorithm are presented.
Perturbation of Dispersive Shallow Water Waves with RosenauKdVRLW Equation and Power Law Nonlinearity P. Razborova, L. Moraru, A. Biswas Romanian Journal of Physics 59,
658676 (2014)
This paper studied dynamical features of dispersive shallow water waves that are modeled by RosenauKdVRLW equation. This model is generalized to power law nonlinearity. Soliton perturbation theory is applied to obtain the adiabatic dynamics of soliton parameters. Ansatz method also obtains exact 1soliton solution to perturbed RosenauKdVRLW equation. Finally, semiinverse variational principle gives an analytical 1soliton solution to this model.
Analytical Description of the Nonlinear Dynamics of BoseEinstein Condensates by Means of Genetic Algorithms Mihaela Carina Raportaru, Jane Jovanovski, Boro Jakimovski, Dragan Jakimovski, Anastas Mishev Romanian Journal of Physics 59,
677685 (2014)
In this paper we show that parallel genetic algorithms provide an accurate analytical description of the nonlinear dynamics of a BoseEinstein condensate. We consider a spherically symmetric condensate subject to periodic and aperiodic parametric excitations and show that the standard variational equation which describe the timeevolution of the condensate has simple analytical solutions. These solutions are obtained using parallel genetic algorithms and allow us to quantify analytically distinct physical processes such as resonant energy transfers and modelockings. The observed efficiency of this method for the aforementioned onedimensional variational equation suggests that this method can be efficiently used for charting the stability spectrum of condensates subject to parametric excitations and possibly for the description of optic waves travelling in nonlinear media.
Exact EinsteinGordon Phantoms and Their Potentials in the 5D Bulk of de Sitter Worlds Adrian Bodnarescu, MarinaAura Dariescu, Ciprian Dariescu Romanian Journal of Physics 59,
686698 (2014)
We aim to generalize the RandallSundrum model, by considering a five dimensional FRW metric, depending on both a scale and a warp function. We derive the corresponding components of the Einstein tensor and write down the 5D Einstein equations with a scalar field as the mattersource. Assuming that the field is static and depends only on the extradimension, we are able to find the scale function, in terms of the Hubble constant. We are dealing with the system of Einstein equations in some special cases and compute the warp function and the amplitude of the scalar field. Furthermore, we postulate a warp function which leads to a phantom in the bulk and come to a potential with broken symmetry, whose constant term can be converted into the AdS_{5} cosmological constant. Finally, one is able to describe the behaviour of the “particle”, along the extradimension, once the brane’s position is fixed.
Eigenvalues and Eigenmodes of an Inclined Homogeneous Truss in a Rotational Field S. Vlase Romanian Journal of Physics 59,
699714 (2014)
The technical applications of the last decades are associated to mechanical systems which work with powerful forces at high velocities. The rigid elements hypothesis, which is used in most engineering applications, does not work in this situation, where the elasticity of the bodies leads to sensibly different behaviors, where big deformations, intense vibrations and mechanical instability phenomena can arise. In this paper we aim to use finite elements in order to obtain the model of a homogenous sloping truss in a rotational field.
Plane Symmetric Universe with Cosmic String and Bulk Viscosity in Scalar Tensor Theory of Gravitation S.D. Katore, A.Y. Shaikh Romanian Journal of Physics 59,
715723 (2014)
A plane symmetric cosmological model is obtained within the framework of a scalartensor theory of Gravitation proposed by SaezBallester [4] when the source for energy momentum tensor is a bulk viscuous fluid containing one dimensional cosmic strings. The physical and kinematical properties of the model have been discussed.
4. D. Saez and V.J. Ballester, Phys. Lett. A. 113, 467 (1985).
Nuclear Physics
Competition between AlphaDecay and Spontantous Fission at Superheavy Nuclei I. Silisteanu, C.I. Anghel Romanian Journal of Physics 59,
724732 (2014)
The most important decay modes for heavy and superheavy nuclei are their αdecay and spontaneous fission. This work investigates the evolution and the competition of these modes in isotopic sequences. We define, extrapolate and use approximation schemes and methods for obtaining halflives incorporating the essential physics of decay process. We compile measurements and theoretical halflives and tabulate recommended values along with total halflives. We evaluate and compare the alpha decay and fission halflives using microscopicmacroscopic and phenomenological methods. The alpha and fission halflives are obtained in terms of a minimal set of parameters determined from the fit of experimental data and results of the shell model rate theory. A summary of the experimental and calculated αdecay and spontaneous fission halflives of the isotopes of elements Rf, Db, and Sg is presented. Some halflife extrapolations for nuclides not yet known are also obtained. The αdecay and fission are powerful tools for investigating the detailed aspects of nuclear structure and reaction dynamics. The decay properties are strongly connected with the singleparticle structure of nuclei.
Condensed Matter
Covering Obliquely Deposited Siox with Polyvinyl Carbazole Changes the Orientation Properties S. Frunza, I. Zgura, L. Frunza, O. Rasoga, P. Gheorghe, A. Petris, V.I. Vlad Romanian Journal of Physics 59,
733744 (2014)
Alignment layers of polyvinylcarbazole (PVK) were obtained by withdrawing from different solutions in toluene onto glass plates having SiOx layers obliquely evaporated in vacuum at 82^{o}. The alignment direction of nematic liquid crystal molecules with cyanend group imposed by bare SiOx layers is changed when these layers are coated with PVK; the same happens with over layers of polyvinylimidazole or of polyvinylcinnamate. The effect is inhibited by doping PVK with fullerene C60 (0.1%), when the liquid crystal orientation specific for bare SiOx obliquely evaporated substrates is obtained. Other nematic (with methoxyend group) does not show change of the orientation properties by covering the SiOx obliquely deposited layers with the mentioned polymer over layers.
Plasma Physics
Modeling of Plasma Flow in a Low Power ArcJet A. Kaminska, A. Bialek, M. Dudeck Romanian Journal of Physics 59,
745756 (2014)
The properties of an argon D.C. arcjet functioning at low electric power (up to 4 kW) and mass flow rate 1.3 g/s are determined. The physical description of the arc takes into account two kinetic temperatures $(T_e,T)$ and non equilibrium condition for the ionization. The plasma properties as velocity, pressure, electron and heavy particles temperatures and densities are calculated by a NavierStokes modeling for stationary and axisymmetric conditions in the cylindrical throat and in the divergent part of the nozzle.
Optical Characterization and Application of an Atmospheric Pressure Ar Plasma in Contact with Liquids for Organic Dyes Degradation D. ZaharieButucel, S.D. Anghel Romanian Journal of Physics 59,
757766 (2014)
Optical emission, temperatures and electron number densities for two kind of plasma generated in contact with liquids are presented. Plasma was generated with a single metallic electrode either in Ar bubbled in liquid or in Ar on the surface of liquid. Both plasmas were tested for organic dye degradation.
Optics
Nonlinear Optics of Intense FewCycle Pulses: An Overview of Recent Theoretical and Experimental Developments D.J. Frantzeskakis, H. Leblond, D. Mihalache Romanian Journal of Physics 59,
767784 (2014)
We provide a brief overview of recent theoretical and experimental studies in the field of nonlinear optics of intense fewcycle pulses, which were performed in a series of relevant physical settings.
Medical Physics
Clinical Application of LinearQuadratic Model in Reirradiation of Symptomatic Bone Metastases L. Rebegea, M. Dumitru, D. Firescu Romanian Journal of Physics 59,
785791 (2014)
Radiotherapy is an important and one of the most effective curative and palliative modality of cancer treatment. Symptomatic bone metastases (M1OSS) represent an important problem in oncology. External beam radiotherapy (EBRT) is effective in palliating pain from bone metastases, being rapid treatment without major toxicities. There are many fractionation schemas and a certain percent of patients requires reirradiation. The question arises which treatment schema is more efficient, knowing the equivalence of the three fractionation schemas: TD = 8 Gy/1 fraction/1 day, TD = 20 Gy/5 fractions/5 days, dose / fraction = 4 Gy and TD = 30 Gy/10 fractions, dose/fraction = 3 Gy. In order to formulate equivalent fractionation schemes, to get information on acute and late responses and also to calculate additional doses after breaks from radiotherapy, for changing of total time of treatment and for reirradiation cases, the linear – quadratic model (LQ) is used.
Atmosphere and Environmental Physics
On the Formation Mechanism of LowLevel Jet over Bucharest’s Airports M. Balmez, S. Ştefan Romanian Journal of Physics 59,
792807 (2014)
Environmental Radioactivity Assessment Studies
on Placement Area of the New Extreme Light Infrastructure Nuclear Physics Facility A. Stochioiu, F. Mihai, C. Stochioiu Romanian Journal of Physics 59,
808816 (2014)
The paper presents environment radioactivity data performed by the monitoring of the Extreme Light Infrastructure Nuclear Physics ELINP building placement area, nuclear physics facility which will be built within Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFINHH), Romania. The studies were necessary in order to achieve the reference values of radioactivity and quality for environment before starting the ELINP nuclear facility building process and the nuclear activities in this new objective. The ELINP building placement area was mapping into lots of about 1000 m^{2} and samples from twenty points were analyzed. Ten thermoluminescent dosimeters were also placed on ELINP area during fortythree days. The studies are based on measurements of radioactivity, especially the gross beta radioactivity in environmental samples, such as: soil, groundwater, spontaneous vegetation and aerosols samples, and ambient dose equivalent rates The results show that the environment radioactivity values obtained by these studies are comparable with those previously obtained through environment radioactivity monitoring in IFINHH area and in different Romanian areas.
Electromagnetic Exposure Influence on Protein Synthesis in Cellulolytic Fungus – An Environmental Issue L. Oprica, E. Ungureanu, G. Vochita, D. Creanga, S. Miclaus Romanian Journal of Physics 59,
817825 (2014)
Experimental investigation focused on electromagnetic pollution influence on fungi degrading wood is presented in this paper. 970 MHz low power microwaves were used to irradiate Phanerochaete chrysosporum cells combining two exposure times and two specific absorption rates – experimentally determined by the scattering parameter method. Total protein content estimation and electrophoretic fractions assay have evidenced diminished biosynthesis with up to 25%, following energy absorption from microwave source, but no qualitative modifications in protein fraction array.
ESR on Some GammaIrradiated Aromatic Herbs R.M. Slave, C.D. Negut, V.V. Grecu Romanian Journal of Physics 59,
826833 (2014)
Gamma irradiated dill and parsley, two very used aromatic herbs, were studied by electron spin resonance (ESR) spectroscopy. Stable radicals are put in evidence and their concentration versus irradiation dose, following a saturated exponential dependence, was determined. ESR spectra structure was simulated with an orthorhombic spin Hamiltonian. The spectra are quite stable in time, contrary to previously reported data. ESR spectroscopy can be used for irradiation identification of such very dry plant samples.
Measurement of Indoor Radon, Thoron and Their Progeny Levels in Dwellings of Ambala District, Haryana, Northern India Using Solid State Nuclear Track Detectors Vimal Mehta, S.P. Singh, R.P. Chauhan, G.S. Mudahar Romanian Journal of Physics 59,
834845 (2014)
Presence of radon, thoron and their decay products in household environment are considered a potential health hazard. Measurement of their levels is an important aspect to assess the threat they may pose to humans. Considering this their measurement from the dwellings of Ambala of Northern India has been carried out using passive technique. The indoor radon concentration varied from 4.8 ± 0.2 Bq m^{–3} to 29.1 ± 1.4 Bq m^{–3} with an average of 13.0 Bq m^{–3} while the thoron concentration in the same dwellings varied from 1.2 ± 0.1 Bq m^{–3} to 69.2 ± 1.8 Bq m^{–3} with an average of 14.4 Bq m^{–3} for the autumn season. The radon progeny levels in the dwellings under study varied from 0.52 to 2.80 mWL with an average of 1.40 mWL, while the thoron progeny levels varied from 0.03 to 1.87 mWL with an average of 0.39 mWL for the autumn season. The annual effective dose received by the inhabitants of these dwellings varied from 0.15 mSv to 2.30 mSv and depends upon the ventilation condition of the dwellings.
MultiCriteria Analysis of Soil Radioactivity in Čačak Basin, Serbia M. Papić, M. Vuković, I. Bikit, D. Mrđa, S. Forkapić, K. Bikit, Ð. Nikolić Romanian Journal of Physics 59,
846861 (2014)
The paper looks at the method of presenting and comparing soil radioactivity on different locations. Activities of natural radionuclides ^{238}U, ^{226}Ra, ^{232}Th, ^{40}K and anthropogenic ^{137}Cs in arable land of Čačak basin were measured. Some 30 soil samples collected from different locations, i.e. the vicinity of the West Morava river, both urban and industrial areas of the town and rural region were analysed. Samples were taken from 0–30 cm depth. According to the values of the ShapiroWilk’s test (0.05 significance level), contents of ^{238}U, ^{232}Th and ^{40}K were within the limits of normal distribution, while ^{226}Ra and ^{137}Cs were not. As espected, statistically significant positive correlation ($p<0.01$) was found between all the natural radionuclides. The analysed sites were ranked using the PROMETHEE method, and the results were presented in graph using the GAIA plane. The ranking involved five criteria which represented the overall activities of each of the radionuclides. The ranking inferred that Ljubić Polje location was the one with the lowest radioactivity, while, in contrast, the location of Trnavska Baluga showed the highest radioactivity level. As regards presence of radionuclides in soil, the comparative study of urban (industrial) and rural areas did not imply any significant differences among the locations. The results of the present study were discussed and compared with related values from several sources found in the literature. Generally, the study infers that soil in Čačak basin has not showed increased levels of radioactivity$.
The ClausiusMossotti Factor in Low Frequency Field of the Powders Resulted from Wastes Combustion R. Giugiulan, I. Malaescu, M. Lungu, N. Strambeanu Romanian Journal of Physics 59,
862872 (2014)
Using the complex dielectric permittivity measurements in the frequency range 25 Hz to 2 MHz, the frequency ($\omega$) dependence of the ClausiusMossotti factor, was determined $K(\omega)$ for some ash powder micro/nanoparticles samples, which resulted from the combustion processes of municipal wastes. The results show that if the ash powder is dispersed in air, the real part of the ClausiusMossotti factor $\rm{Re}[\tilde{K}(\omega)]$, for all samples and at all frequencies in the investigated range is positive. Therefore, filtering of flue gas using positive dielectrophoresis (pDEP) is possible by trapping the nanoparticle in the area of the strongest electric field. The theoretical study which was performed in this paper shows that the $\rm{Re}[\tilde{K}(\omega)]$ may change from a positive to a negative value, at a critical frequency, $f_c$ (which decreases from 1.416 kHz to 0.31 kHz), if the dielectric permittivity of the dispersion medium increases from 3 to 10. Therefore, there is a shift from positive dielectrophoresis (pDEP) to negative dielectrophoresis (nDEP), and the particles can move from regions of high electric field gradient to regions of low electric field gradient. The results obtained show that there is the possibility of using the dielectrophoresis, for retaining through manipulation and spatial separation controlled by the nanoparticles from the powder samples investigated, leading to purification of exhausted combustion gases and reduction of the air pollution.
Assessment of Human Error Importance in PWR PSA Kaveh Karimi, Faramarz Yousefpour, Ali Abbaspour Tehranifard, Mohammad PourgolMohammad Romanian Journal of Physics 59,
873885 (2014)
Pilot errors have undeniable role in the total risk of engineering systems including Nuclear Power Plants (NPPs). Analysis of this role is the subject of this paper. Human actions affecting the risk of a typical pressurized water reactor are identified using Probabilistic Safety Assessment (PSA) model. And Human Error Probabilities (HEPs) for each action is estimated by using Human Reliability Analysis (HRA) techniques. Thereafter, human actions are incorporated in the PSA model. Finally the total risk of NPP is calculated which becomes 1.99E05 per reactor critical year in terms of Core Damage Frequency (CDF). Sensitivity analyses showed that highly reliable operator actions, defined to be actions with HEP of one order of magnitude lesser than normal value, would decrease the CDF up to 12.76% while, perfect human actions, defined as those actions with zero HEP, show a 14.29% decrease in the CDF. The interesting point found in the sensitivity analyses is that less reliable actions would increase the CDF up to 563%. Just similar to highly reliable actions, less reliable actions are those actions with HEP of one order of magnitude higher than the normal value. With no credit to all operator actions, i.e. setting all HEP=1, CDF would rise up to 3.65E2 per reactor critical year.
