Volume 61, Number 78, 2016
Mathematical and Theoretical Physics
Geodesics Associated to the Balanced Metric on the SiegelJacobi Ball S. Berceanu Romanian Journal of Physics 61,
11371160 (2016)
We determine the Christoffel’s symbols for the SiegelJacobi ball endowed with the hermitian balanced metric. We study the equations of geodesics on the SiegelJacobi ball. We calculate the covariant derivative of oneforms in the variables in which it is expressed the balanced metric on the SiegelJacobi ball.
Dynamics of Entanglement of ThreeMode Gaussian States in the ThreeReservoir Model Hoda Alijanzadeh Boura, Aurelian Isar, Yahya Akbari Kourbolagh Romanian Journal of Physics 61,
11611171 (2016)
We describe the dynamics of entanglement of threemode Gaussian states of a system composed of three bosonic modes, each one immersed in its own thermal reservoir, in the framework of the theory of open systems based on completely positive quantum dynamical semigroups. By using the criteria for the separability of threemode systems, we classify the states by different values of the parameters characterizing the system and the thermal reservoirs. We consider a fully inseparable state as an initial state and show that for definite values of temperature and dissipation constants, the class of entanglement to which the state of the system belongs is changing during its time evolution. For all nonzero values of temperatures of the thermal baths, suppression of entanglement of the initial state always takes place, and in the limit of large times the state is fully separable, corresponding to an asymptotic product state.
A New Application of the Fractional Logistic Map LanLan Huang, Dumitru Baleanu, GuoCheng Wu, ShengDa Zeng Romanian Journal of Physics 61,
11721179 (2016)
The fractional chaotic map started to be applied in physics and engineering to properly treat some realworld phenomena. A shuffling method is proposed based on the fractional logistic map. The fractional difference order is used as a key. An image encryption scheme is designed by using the XOR operation and the security analysis is given. The obtained results demonstrate that the fractional difference order makes the encryption scheme highly secure.
Atomic and Nuclear Physics
Heavy Ion Orbiting and Regge Poles (III) F. Carstoiu, M. Lassaut, L. Trache, V. Balanica Romanian Journal of Physics 61,
11801197 (2016)
We discuss two reactions initiated by the loosely bounded ^{6}Li in an energy window where the interaction with light targets is strongly refractive and moderately absorbing. The surface transparency of the optical potential allows a considerable internal barrier component of the scattering amplitude which leads to significant refractive effects and diffractive scattering at large angles due to Regge poles located near the real axis, close to the orbiting momentum. The folding potentials based on realistic effective NN interactions revealed a number of phase equivalent discrete solutions with real volume integrals close to the bare potential values ($N_\nu \simeq 1$). This suggests that the real part of the dynamic polarization potential arising from the coupling to the breakup channel is small.
Investigation of RGB Spectral Components in the Images Captured through Gamma Rays Affected Optical Focusing Lens MR. Ioan Romanian Journal of Physics 61,
11981206 (2016)
Most times, the activities that take place in hostile ionizing radiation environments (hot cells) need to have a proper visual monitoring system. In these cases, glass is the connection bridge between that environment and the one where the surveillance takes place. The purpose of this paper is the one to study of how the RGB spectral components of the images captured by such systems are affected by their exposure to ionizing radiation and how can be reversed to their initial performance by applying RGB dose correlated digital corrections. The main optical issues of the glass transmittance windows are the one of forming of colour centres, due to their interaction of the ionizing radiation, which causes glass browning phenomenon. This phenomenon has a major impact on the optical properties of the glass, such is transmittance, leading to lower and lower image quality. To obtain different gamma radiation dose, 1.25 MeV mean energy gamma quanta were used, provided by a ^{60}Co source (IFINHH). Different optical focus components were exposed to a dose rate level of about 5.3 kGy/h ± 3 %. Practically, the results after RGB digitally processing of the images captured through irradiated optical components, where similar to the ones obtained by thermal processing of them. This digitally enhancing method is easier to be done, and it is more economic. The optical characterization of the images was done by using a Canon digital photo camera connected to a PC.
Investigation of the Natural and Artificial Radioactivity in Graphite from the VVRS Nuclear Reactor Deposit by GammaRay Spectrometry A. Scarlat, A. Pantelică, I. Iorga, M. Drăguşin Romanian Journal of Physics 61,
12071212 (2016)
In view of radiological characterization of the virgin graphite from a deposit of the VVRS nuclear research reactor of IFINHH at Magurele, Romania (in decommissioning process) activity concentrations of ^{60}Co and ^{137}Cs artificial radionuclides, ^{226}Ra (by ^{214}Pb and ^{214}Bi), ^{238}U (by ^{234}Th), ^{232}Th (by ^{228}Ac, ^{212}Pb, ^{208}Tl), and ^{40}K natural radionuclides have been investigated by gammaray spectrometry. Their values were found to be lower than the clearance levels given by the radiological safety norms, being situated in the following ranges (Bq·kg^{1}): 2.111.9 for ^{60}Co, 2.84.3 for ^{226}Ra, and 2.13.0 for ^{232}Th; detection limits of 0.72.3 for ^{137}Cs, 1125 for ^{238}U, and 1440 for ^{40}K were also determined. The presence of ^{60}Co in graphite was probably due to an accidental contamination during the reactor decommissioning works.
Condensed Matter
Magnetic and Magnetocaloric Properties of Er_{x}Y_{1x}Co_{2} compounds with $x \le 0.3$ E. Burzo, I. Balasz, L. Chioncel Romanian Journal of Physics 61,
12131223 (2016)
The magnetic properties of Er$_{1x}$Y$_{x}$Co$_2$ compounds with $x \le 0.3$ were studied in a large temperature range and fields up to 12 T. Band structure calculations were also performed. The complex and interdependent exchange interactions, at the level of unit cell, are discussed. The cobalt magnetic behaviour above the Curie temperature, has been analysed in the spin fluctuations model. High entropy changes were shown when the compounds show first order magnetic transitions. The specific renormalized cooling powers decrease as the erbium is gradually replaced by yttrium.
The Transport of Dirac Fermions through Certain OneDimensional Quantum WireStructures D.M. Baltateanu Romanian Journal of Physics 61,
12241234 (2016)
The relativistic transport through semiconductorbased quantum wires in electric field is investigated, using a relativistic extension of the transfer matrix. The effects of the positiondependent effective mass and the electric field on transmission are analyzed and some comments on oscillatory behavior of the relative difference between the relativistic and the nonrelativistic coefficients are made.
Gas Diffusion Layer and Reactant Gas Channel Influence on the Performance of a HTPEM Fuel Cell V. Ionescu Romanian Journal of Physics 61,
12351244 (2016)
Proton exchange membrane fuel cells (PEMFC) are highly efficient power generators, being used recently in a clean hybrid power supply system. Comsol Multiphysics, a commercial solver based on the Finite Element Method (FEM) was used for developing a three dimensional model of a high temperature PEMFC in order to study operation mode and performance of the fuel cell. Cathode gas flow velocity influence on the cell performance was investigated. Gas channel geometry for cell model was optimized by varying the channel width/GDL width ratio $\lambda$ at values between 0.3 and 0.8, choosing a low operating gas flow velocity of 0.06 m/s and computing the following parameters: water and oxygen molar concentrations at cathode catalyst layer, pressure drop variation across anode GDL and velocity field distribution across the cathode gas channel.
Nonlinear Diffusion in Cubic Crystals J. Janavičius, S. Turskienė Romanian Journal of Physics 61,
12451254 (2016)
We have made a mathematical consideration of an important case of nonlinear diffusion of impurities for a threedimensional cubic crystals case through a square window or point sources in the $x\;y$ plane for more exact evaluation of technological parameters for the production of electronic devices or crystals properties modification. The well known nonlinear diffusion model with diffusion coefficients proportional to the concentration of impurities defining spreading of impurities with finite velocity was used. The solutions of the presented nonlinear diffusion equation determine profiles of impurities more exactly. The directions of diffusion can be included taking in the care crystals symmetry. For approximate analytical solving of the threedimensional nonlinear diffusion equation we introduced similarity variables. The approximate analytical solution of the transformed equation was expressed by Taylor series using the expansion about the maximum penetration depths of the impurities in $x\;y\;z$ axes including the square terms.
Improvement of Spectrophotometric Method for Determination of Phenolic Compounds by Statistical Investigations O.R. Bancuta, A. Chilian, I. Bancuta, R.M. Ion, R.Setnescu, T. Setnescu, A. Gheboianu Romanian Journal of Physics 61,
12551264 (2016)
The determination of phenolic compounds by the spectrophotometric method has many advantages: it is very easy to implement, requires less resources and provides a global response concerning the content of phenolic compounds. This spectro photometric method is known as the FolinCiocalteu index determination. In the literature are proposed several wavelengths at which can be made FolinCiocalteu index determination: 725 nm, 750 nm, 760 nm, 765 nm. In this paper, it was shown, using statistical methods, the best wavelength at which can be determined the FolinCiocalteu index.
Spectroscopic and DFT Investigation of Benzaldehyde Isonicotino – Hydrazide Compound I.B. Cozar, A. Pîrnău, L. Szabo, N. Vedeanu, C. Nastasă, O. Cozar Romanian Journal of Physics 61,
12651275 (2016)
The potential antimicrobial compound aroylhydrazone 4[2(4methyl2phenylthiazole5yl)2oxoethoxy]benzaldehyde isonicotino  hydrazide (BINH) was synthesized and investigated by FTIR, FTRaman, ^{1}HNMR methods and also by DFT calculations at B3LYP/631G(d) level of theory in order to elucidate some structural aspects. Very good correlation between the vibrational and theoretical data shows that the proposed optimized structure is very close to reality. The molecular electrostatic potential (MEP) of this molecule suggests a parallel adsorbed orientation on the silver nanoparticles by the oxygen atoms and the $\pi$electrons of rings. NMR data show a monomeric behavior of this compound in DMSOsolutions.
Biophysics and Medical Physics
Fractal Dimension of the Trajectory of a Single Particle Diffusing in Crowded Media Laura Pitulice, Dana Craciun, Eudald Vilaseca, Sergio Madurga, Isabel Pastor, Francesc Mas, Adriana Isvoran Romanian Journal of Physics 61,
12761286 (2016)
Using Monte Carlo simulations we have modeled the diffusion of a single particle in two and threedimensional lattices with different crowding conditions given by distinct obstacles size and density. All registered data emphasize that diffusion process is anomalous and diffusing particle describes fractal trajectories. We have introduced a new timescale fractal dimension, $d_m$, which is related to the anomalous diffusion exponent, $\alpha$. This allows us to relate the wellknown lengthscale fractal dimension of the random walk, $d_w$, to the new one introduced here as a timescale fractal dimension. Moreover, the 3D simulations consider similar conditions to those used in our previous FRAP experiments in order to reveal the relationship between the length and timescale fractal dimensions.
Blood Pressure and Flow Values in Small Vessels Angioarchitectures: Application for Diabetic Retinopathy Luminiţa Moraru, Cristian Dragos Obreja, Simona Moldovanu, Antoaneta Ene, Anjan Biswas Romanian Journal of Physics 61,
12871298 (2016)
This paper aims to study the blood pressure and flow at any site (or node) based on the branching asymmetry, the number of nodes and elements of a branching tree in the real retinal vascular structures. The analysis of blood flow in the circulatory system is based on NavierStokes equation, Poiseuille flow and an asymmetry parameter in order to gather information on the pressure field distribution as well as flow profile. Two retinal vessel geometries were investigated, i.e. normal human eye and diabetic retinopathy. The measured branching asymmetry is 0.4. Only two exceptions were established for diabetic retinopathy images. For the analyzed structures, the pressure gradient have almost similar profiles indicating that the overall behavior of pressure drop in all the vessels remains very much unaltered. Changes in the blood flow profiles were highlighted for diabetic retinopathy pathology ($p < 0.001$). This study is a first step in a right direction toward personalized medicine for pathologies related to the dynamics of blood flow.
Confirmatory versus Exploratory Statistical Analysis of Functional Brain Imaging Data Simona Spînu, LuciaElena Enciu, Radu Mutihac Romanian Journal of Physics 61,
12991311 (2016)
The present overview briefly highlights the advances and limitations in functional neuroimaging by critically comparing typical confirmatory and exploratory analysis of functional brain imaging data. Multivariate methods like independent component analysis (ICA) and fuzzy cluster analysis (FCA) were applied to reallife functional neuroimaging data and comparatively discussed versus univariate inferential statistical techniques like the general linear model (GLM) implemented in SPM and waveletbased SPM (WSPM).
Dosimetrical Evaluation and Clinical Implementation of a StrutAdjustedVolumeImplant SAVI Device Used for Accelerated Partial Breast Irradiation Ş. Morcovescu, C. Cosma, J.D. Morton Romanian Journal of Physics 61,
13121319 (2016)
The SAVI (the Strut Adjusted Volume Implant) device is one of the most novel devices used in Accelerated Partial Breast Irradiation (APBI). Various dosimetric parameters, as well as doses to adjacent critical structures, have been evaluated in 121 patients in this single institution 5year retrospective study, using dose volume histogram (DVHs): Coverage Index (CI), cavity and planning target volumes (PTV and PTV_EVAL), Max Skin Dose (MSD), Max Chest Wall Dose (MCWD), Skin Bridges (SB), ChestWall Bridges (CWB). Our analysis demonstrates the dosimetric versatility and outlines the clinical implementation process of the SAVI brachytherapy device, especially for APBI cases that require more flexible dose optimization, for both coverage of PTV volumes and sparing of dose to adjacent critical structures.
FollowUp Measurements to Estimate the Exposure to Patients in the Mofettes from Covasna County (Romania) R. Incze, B. Papp, B.D. Burghele, C. Cosma, S. Gyila Romanian Journal of Physics 61,
13201329 (2016)
In the Harghita postvolcanic range (Eastern Carpathians) there are many occurrences of dry CO_{2} emanations, called mofettes, from which more than 30 are from Covasna County (Romania). These emanations contain mainly CO_{2} but also important quantities of radon, thoron and other gases. Mofettes are used for curative purposes of several illnesses, in most cases without medical supervising. We proposed to measure the radon activity concentration levels and to determine the effective dose for some frequented mofettes. The radon activity concentrations above the mofettes indoor air range between 157 and 6737 Bq·m^{3}, while within the gas pools values between 1706 and 7601 Bq·m^{3} have been measured. The effective dose received by the patients during a cure is between 0.015 and 0.148 mSv, which do not exceed hardly the annual effective population dose of 1 mSv (i.e. 10%, which not represent a risk for the patient's health, during a treatment period). In other ways, this dose represents only 5 % from the natural annual dose received by Romanian population.
Optics
LBand Harmonic Mode Locking of Single, Two, and ThreeSoliton Bunches from CBand Amplifier in a FigureofEight Fiber Laser K. Guesmi, G. Semaan, M. Salhi, Y. Meng, F. Bahloul, H. Leblond, F. Sanchez Romanian Journal of Physics 61,
13301338 (2016)
We report the experimental emission above 1.6 μm of harmonic mode locking of single, two, and threesoliton bunches in a Cband Er:Yb codoped silica fiber laser. The laser cavity consists of two connected fiber loops in the figureofeight configuration. In such a system the modelocking regime arises spontaneously due to the nonlinear optical loop mirror, which acts as a saturable absorber. The 1.6 μm oscillation is enhanced by minimizing the linear intracavity losses. Depending on the pump power and the polarization controllers, the laser generates harmonic mode locking above 1.6 μm containing patterns with one, two or three pulses. These two last regimes have not been achieved so far at a longwavelength range.
Study of Paschen Condition in the Frame of Monochromatization – Effect of Light L.C. Ciobotaru, I. Gruia Romanian Journal of Physics 61,
13391353 (2016)
The present paper deals with the study of the more suitable ac/dc dischargestype in which could appear the monochromatization of visible light (the Meffect) emitted by an (Ne/Ar +hydrogen) electronegativeelectropositive gas mixtures in moderate pressures range of 20 ÷ 300 torr and their main characteristics, namely: the breakdown voltage, the subsequent influence of the polarization voltage and of negative ions production on it, the optimum frequency of the applied voltage, the values of the discharge current, the temporal evolution of the applied voltage, currents discharge and intensity of the emitted monochrome light pulse. The paper presents also the intercorrelations between these characteristics and their optimum values in the given experimental conditions.
Environmental and Earth Physics
A Multidimensional Approach to the Influence of Wind on the Variations of Particulate Matter and Associated Heavy Metals in Ploiesti City, Romania D. Dunea, S. Iordache, C. Radulescu, A. Pohoata, I.D. Dulama Romanian Journal of Physics 61,
13541368 (2016)
The paper presents a complex analysis of airborne particulate matter (PM) levels influenced by temperature and wind in Ploiesti city, involving multisource data processing, crossspectrum analysis, kriging interpolation of in situ measurements, and backward air trajectory modeling. The analysis pointed out the spatiotemporal variability of PM and associated heavy metals.
PIXE Analytical Method Applied in the Study of Environmental Samples Used as Bioindicators E.D. Chelarescu, I.D. Dulama, A.I. Gheboianu, I.A. Bucurica, D. Pacesila Romanian Journal of Physics 61,
13691379 (2016)
In this study we apply Proton Induced XRay Emission (PIXE) spectrometry to determine the heavy metal content of some environmental certified reference materials and moss samples. The PIXE experiments were performed using a proton beam provided by the 3 MV TandetronTM particle accelerator from the National Institute for R&D in Physics and Nuclear Engineering Horia Hulubei (IFINHH) in MagureleBucharest. The trace elements in mosses pellets and certified standard samples were measured. The elements identified were: Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and As, and quantitatively determined were: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn. The concentrations values of heavy metals in the analyzed samples determined by PIXE technique were compared with the results obtained by Flame Atomic Absorption Spectrometry (FAAS) method.
Determination of 54 Elements in Lichen Transplants: Comparison of INAA, ICPMS, and EDXRF Ana Pantelica, Vadim Cercasov, Eiliv Steinnes, Peter Bode, Hubert Th. Wolterbeek Romanian Journal of Physics 61,
13801388 (2016)
Three multielement techniques employed for analysis of lichen transplants deployed at sites in Romania with strongly differing exposure to air pollutants were compared with respect to precision and determination limits for 54 elements. The results obtained for Evernia prunastri (unexposed and 6 months' exposure at three sites) are presented here. The techniques were energy dispersive Xray fluorescence analysis (EDXRF), sectorfield inductivelycoupled plasma mass spectrometry (ICPMS), and instrumental neutron activation analysis (INAA). From an assessment of the data the EDXRF values were preferred for 3 elements (Ni, Cu, Pb), ICPMS for 18 elements (B, Mg, P, Ga, Rb, Sr, Y, Mo, Ag, Cd, In, Sn, Cs, Ba, Pr, Hg, Tl, Bi), and INAA for 23 elements (Na, Al, Cl, Ti, Cr, Co, Se, Br, I, La, Ce, Sm, Eu, Tb, Dy, Yb, Lu, Hf, Ta, W, Au, Th, U). For the remaining 10 elements (S, K, Ca, Sc, V, Mn, Fe, Zn, As, Sb) two or all three techniques gave results of similar quality. In spite of good performance relative to certified reference materials the ICPMS data for some elements were systematic low relative to corresponding data from INAA and EDXRF, presumably because the samples contained mineral matter not dissolved in the nitric acid dissolution for ICPMS.
Fuzzy Logic Procedure for Computing Global Solar Irradiation R. Boata Romanian Journal of Physics 61,
13891394 (2016)
In this paper a new fuzzy logic model for estimating hourly global solar irradiation is reported. The quantity directly processed by the proposed algorithm is the hourly lost component, defined as the difference between measured and estimated in clear sky conditions of hourly global solar irradiations. The algorithm has a general character and it can be applied in any location. Data measured in Timisoara, which can be considered as an arbitrary selected location, are used for building and testing the model. Overall results show an acceptable level of accuracy of the proposed fuzzy model.
Multipole Traps as Tools in Environmental Studies Bogdan M. Mihalcea, Cristina Stan, Liviu C. Giurgiu, Andreea Groza, Agavni Surmeian, Mihai Ganciu, Vladimir Filinov, Dmitry Lapitsky, Lidiya Deputatova, Leonid Vasilyak, Vladimir Pecherkin, Vladimir Vladimirov, Roman Syrovatka Romanian Journal of Physics 61,
13951411 (2016)
Trapping of microparticles, nanoparticles and aerosols is an issue of major interest for physics and chemistry. We present a setup intended for microparticle trapping in multipole linear Paul trap geometries, operating under Standard Ambient Temperature and Pressure (SATP) conditions. A 16electrode linear trap geometry has been designed and tested, with an aim to confine a larger number of particles with respect to quadrupole traps and thus enhance the signal to noise ratio, as well as to study microparticle dynamical stability in electrodynamic fields. Experimental tests and numerical simulations suggest that multipole traps are very suited for high precision mass spectrometry measurements in case of different microparticle species or to identify the presence of certain aerosols and polluting agents in the atmosphere. Particle traps represent versatile tools for environment monitoring or for the study of manybody Coulomb systems and dusty plasmas.
Input Parameters for the Probabilistic Seismic Hazard Assessment in the Eastern Part of Romania and Black Sea Area I.A. Moldovan, M. Diaconescu, E. Popescu, M. Radulian, D. TomaDanila, A.P. Constantin, A.O. Placinta Romanian Journal of Physics 61,
14121425 (2016)
In this study we have used the most reliable and homogeneous seismic datasets at the European scale, covering historical and modern instrumental seismicity until present days for the Eastern part of Romania and the Black Sea Area for computing the statistical parameters of seimogenic sources and assessing the probabilistic hazard in the South Eastern part of Romania.
Investigation of Ionospheric Precursors of Earthquakes in Romania Using the Romanian GNSS/GPS Network Eduard Ilie Nastase, Christina Oikonomou, Dragos TomaDanila, Haris Haralambous, Alexandra Muntean, Iren Adelina Moldovan Romanian Journal of Physics 61,
14261436 (2016)
We examine the lithosphereatmosphereionosphere interaction with respect to earthquake events using Total Electron Content (TEC) data deriving from the Romanian permanent GPS network by applying three different techniques: a) estimation of TEC deviations from the mean state, b) CrossCorrelation Analysis and c) Spectral Analysis. The analysis concerns four seismic events that took place in Romania with magnitude ranging from 5.2 to 6.0. The aim is to identify and study possible ionospheric precursory phenomena linked to these seismic events.
Detection of Events in a Multidisciplinary Network Monitoring Vrancea Area VictorinEmilian Toader, IrenAdelina Moldovan, Alexandru Marmureanu, Constantin Ionescu Romanian Journal of Physics 61,
14371449 (2016)
This paper describes the modalities of detection of events in a multidisciplinary network that monitor seismicity, telluric field, magnetic field, electricelectrostatic field, radio ULF waves, air ionization, radon concentration, solar radiation, infrasound, light and acoustic phenomena, meteorological parameters, airearth temperatures, satellite data with application in seismic Vrancea area (bending zone of Carpathians mountains). The most part of data analysis is automatically done into a distributed structure. Methods used are general but the measured parameters have to be adapted to particularities of monitoring area. Vrancea is a complex zone characterized by intermediate depth earthquakes concentrated and distributed on several levels deep. Data acquisition is followed by their analysis (detection, effects evaluation) and automatic transmission of alerts to beneficiaries specialized in emergency situations (Inspectorate for Emergency Situations, organizations involved in managing special events). Network monitoring allows tracking of climate change and it sends information in real time.
