Volume 71, Number 1, 2019
 
THEORETICAL, MATHEMATICAL, AND COMPUTATIONAL PHYSICS
 
Solving Schrödinger equation for a particle in one-dimensional lattice: an homotopy perturbation approach
TIJANA KEVKIC, VLADICA STOJANOVIC, DRAGAN PETKOVIC
Rom. Rep. Phys. 71, 101 (2019)
Abstract. In this paper, a novel approach for an approximate solving Schrödinger equation for a particle in the one-dimensional lattice with the periodic potential is described. This approach, based on the homotopy perturbation method (HPM), gives an approximate analytic solution which has a high degree of convergence, and at the same time high degree of accuracy. The convergence of the HPM is examined and formally confirmed. In addition, the efficiency of the HPM method is illustrated in two examples.
Article no. 101: PDF 
Bright-dark lump wave solutions for a new form of the (3+1)-dimensional BKP-Boussinesq equation
LAKHVEER KAUR, ABDUL-MAJID WAZWAZ
Rom. Rep. Phys. 71, 102 (2019)
Abstract. In this work, we explore a variety of lump solutions, generated from quadratic functions, for a new form of the (3+1)-dimensional BKP-Boussinesq equation, by employing the Hirota's bilinear form. The sufficient and necessary conditions, which demonstrate analyticity, positiveness, and rational localization of the solutions in a systematic manner, are constructed and examined. Moreover, the aforementioned equation has been reduced dimensionally. This will enable us establishing corresponding lump solutions with free parameters, which play indispensable role for influencing and controlling the phase shifts, shapes and energy distributions and propagation di- rections, for these solutions. The dynamical characteristics of acquired lump solutions have been examined visually, leading to formation of bright-dark lump waves.
Article no. 102: PDF 
Classical and fractional aspects of two coupled pendulums
D. BALEANU, A. JAJARMI, J.H. ASAD
Rom. Rep. Phys. 71, 103 (2019)
Abstract. In this study, we consider two coupled pendulums (attached together with a spring) having the same length while the same masses are attached at their ends. After setting the system in motion we construct the classical Lagrangian, and as a result, we obtain the classical Euler-Lagrange equation. Then, we generalize the classical Lagrangian in order to derive the fractional Euler-Lagrange equation in the sense of two different fractional operators. Finally, we provide the numerical solution of the latter equation for some fractional orders and initial conditions. The method we used is based on the Euler method to discretize the convolution integral. Numerical simulations show that the proposed approach is efficient and demonstrate new aspects of the real-world phenomena.
Article no. 103: PDF 
 
ATOMIC, MOLECULAR, AND NUCLEAR PHYSICS
 
An XRF, XRD, FTIR, FT RAMAN, digital radiography and UV photography study of some classical pigments, primers and binders used in panel painting
Sister SERAFIMA, O. G. DULIU, M.-M. MANEA, A.-V. BOJAR, C. COSTEA, D. BIRGAOANU, O.-C. BARBU
Rom. Rep. Phys. 71, 201 (2019)
Abstract. In order to evidence to which extent noninvasive/less invasive analytical techniques could be used for a complete characterization of panel painting, X-ray Fluorescence (XRF), Fourier Transform Infrared (FT-IR) and Raman (FT-Raman) Spectroscopy, Digital Radiography (DR) and UV Photography (UVP) were used to contactless investigate a panel model painting realized following traditional XVIII-th and XIX-th century techniques. Consequently, a chalk primer lime tree panel was painted with tempera paints based on mineral pigments yellow mica (phlogopite), ultramarine, lead white, led minium, ochre and cinnabar as well as with a 20 μm golden foil while the mineralogical composition of each pigment was determined by X-ray diffraction (XRD). XRF and FT-Raman spectroscopy and, at a lesser extent, DR gave a more com- plete information regarding the elemental composition of the majority of pigments but the unequivocal identifying was done by XRD, in order to furnish the mineralogical composition of the pigments. The Digital Radiography allowed a better discrimination of the pigments containing high atomic number elements while FT-IR spectroscopy showed to be useful in identification of the organic egg yolk binder, he damar var- nish and also of the chalk primer starting from the vibrational spectrum of different moieties.
Article no. 201: PDF 
Computational method for the determination of intense gamma-rays sources activity by using GEANT4
M.-R. IOAN, C. POSTOLACHE, V. FUGARU, S. BERCEA, A. CELAREL, C. CENUSA
Rom. Rep. Phys. 71, 202 (2019)
Abstract. In this paper, a method for the determination of intense gamma-rays sources activity by using GEANT4 (Geometry And Tracking) is proposed. The method is recommended mainly for the cases when the activity of an intense gamma-rays source is unknown and there are no other classical activity determination methods available, or the existing ones are affected by higher uncertainties. The method is based on the fact that starting from an experimental determination of the absorbed dose rate value (well-knowing of all the exposure conditions), the activity of the involved gamma-rays source can be determined. The experimental absorbed dose rate determination can be performed by using a calibrated high performance dosimeter, in order to assure the traceability of the result.
Article no. 202: PDF 
 
PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
 
Monte-Carlo simulation of muon direction for particle astronomy aplications
B. ALKOTBE, B. MITRICA, D. STANCA, M. NICULESCU-OGLINZANU, I. BRANCUS, A. BALACEANU, B. CAUTISANU, A. GHERGHEL-LASCU, A. MUNTEANU, P. DOLEA, O. CRISTEA, D.S. MUATAZ, L. NITA, A. ROSU
Rom. Rep. Phys. 71, 301 (2019)
Abstract. We report on the Monte-Carlo simulation results in order to see the difference between the cosmic ray primary particle's angle of incidence and the muon's azimuth. The simulations have been performed using the CORSIKA code applied for different primary particle energies and incident angles. The CORSIKA code is a versatile program for particular simulation of cosmic ray extensive air showers induced by high energetic primary cosmic rays. The observed difference between the primary particle's incident angle and the muon azimuth is smaller with the increase of the muon's energy. The difference decreases from several degrees up to less than 0.1 degrees for muon's energies greater than 150 GeV. Based on the results we had started some simultaneous measurements of the underground muon flux correlated with observation of the sky by using an optical telescope. The measurements of the muon flux are currently in progress using the directional detector (Si-RO) located in the underground laboratory of IFIN-HH from Slanic Prahova.
Article no. 301: PDF 
Flow studies in nucleus-nucleus collisions at FAIR-GSI available energies
O. RISTEA, C. RISTEA, A. JIPA, T. PETRUSE, T. ESANU, M. CALIN
Rom. Rep. Phys. 71, 302 (2019)
Abstract. In this work, the elliptic flow coefficients for charged pions, kaons and protons as a function of transverse momentum pT, at midrapidity (-0.5 < y < 0.5), in Au-Au collisions at three colliding energies (√sNN=3, 5 and 7.7 GeV) simulated with UrQMD and AMPT-SM (AMPT with string melting version) codes are presented. The scaling of v2 with the number of valence quarks (nq) has been studied as a function of transverse kinetic energy per quark, KET/nq. A deviation from quark-number scaling is observed at larger values of KET/nq in non-central Au-Au collisions for both simulation codes. The 7.7 GeV Au-Au simulated results were compared with STAR experimental data.
Article no. 302: PDF 
Predictions on some possible phase transitions in Au-Au nuclear central collisions in CBM experiment at FAIR-GSI
NICOLAE GEORGE TUTURAS, ALEXANDRU JIPA, ADAM JINARU, ADRIAN CHITAN
Rom. Rep. Phys. 71, 303 (2019)
Abstract. In this work, we present numerical calculations for the excitation function of the antiparticle to particle ratio for the 6-25 A GeV energy interval, which have a predictive character for the CBM experiment at FAIR-GSI. For two energy intervals, plateau shapes are observed, in contrast to the general tendency of the antiparticle to particle ratio growth with energy increase, which may suggest the emergence of the mixed phase for a fraction of time. The results of our calculations are in good agreement with the results from other papers based on experimental data (AGS, HADES). In the analysis of the systematic dependence of K-/K+on the p/p ratios, quasi-coincidences or "points returns" for two, three consecutive energies appear, which may suggest possible phase transitions in the newly formed nuclear matter in relativistic heavy ion collisions.
Article no. 303: PDF 
 
OPTICS AND PHOTONICS, PLASMA, LASER AND BEAM PHYSICS
 
Two instances of image super-resolution using sensor raster scanning and deconvolution
P. C. LOGOFATU, V. DAMIAN, T. VASILE, M. L. PASCU
Rom. Rep. Phys. 71, 401 (2019)
Abstract. Super-resolution reconstructs a high-resolution image from one or more low-resolution recorded images. It uses a variety of hardware techniques, such as sensor raster scanning, or software techniques, such as interpolation, iterative back- projection, and the regularized methods, and it is useful in a variety of applications, such as video surveillance, medical diagnosis and remote sensing. Two applications based on the same technique are presented here in some detail: first, the hyperspectral characterization of a THz beam generated by a Time Domain Spectroscopy device and second, the resolution-enhanced photography. In both cases, images recorded by the sensor during a subpixel raster scan were interwoven in a high-resolution image, subsequently deconvoluted with a constant square kernel of the size of the sensor pixel. For hyperspectral characterization, regularization was necessary, whereas for resolution-enhanced photography, simple deconvolution sufficed. Magee's approach to super-resolution, which does not use convolution, was analyzed and rejected.
Article no. 401: PDF 
Study on periodic interactions of optical solitons in dispersive optical fibers
SHUBIN WANG, GUOLI MA, XIN ZHANG, MOHAMMAD MIRZAZADEH, MEHMET EKICI, QIN ZHOU, WENJUN LIU
Rom. Rep. Phys. 71, 402 (2019)
Abstract. The quality of optical communication systems can be effectively improved by controlling soliton interactions. In this paper, periodic interactions of optical in optical fibers are studied. Analytic two-soliton solutions of a variable-coefficient higher-order nonlinear Schrödinger equation are presented, and the influences of the corresponding model parameters are discussed. Both the in-phase and out-of-phase interactions of optical solitons are analyzed. The numerical results indicate that the periodic interactions of optical solitons can be controlled in order to decrease the bit error rate of fiber communication systems.
Article no. 402: PDF 
On the dynamics of dust-acoustic and dust-cyclotron freak waves in a magnetized dusty plasma
N. AKHTAR, S. A. EL-TANTAWY, S. MAHMOOD, ABDUL-MAJID WAZWAZ, HAFEEZ UR-REHMAN, AMAN-UR-REHMAN
Rom. Rep. Phys. 71, 403 (2019)
Abstract. The modulational instability of dust-acoustic wave (DAW) and dust-cyclotron wave (DCW) in a three-component plasma that consists of dust, ions, and electrons in a magnetized dusty plasma is investigated. Moreover, the freak/rogue waves creation and propagation of DAW and DCW in the present plasma system are reported. Electrons and ions both follow the Maxwellian distribution, while the negatively charged dust is taken to be dynamic. For studying MI, a nonlinear Schro ̈dinger equation (NLSE) is obtained using the Krylov-Bogoliubov-Mitropolsky method. The MI criterion for the NLSE is defined precisely and investigated numerically for DAW and DCW. The stable and unsteady regions of the modulated wave packets were accurately quantified based on the relevant physical parameters. The effects of relevant physical parameters namely, the magnetic field intensity, electron to dust density concentration ratio, ratios of effective temperature to electrons and ions temperature, and angle of wave propagation on both stable and unstable regions of DAW and DCW are examined numerically. It is found that, within unstable regions, a random perturbation of the amplitude grows and thus leads to a creation of freak/rogue waves. In order to demonstrate the effects of the physical parameters on the rogue waves (RWs) profile, the relevant numerical analysis of the rational solution of the NLSE is presented. Also, the higher-order solutions/or the super RWs are reported. The possible observation of propagation of fundamental RWs and super RWs in space plasmas and in laboratory experiments is also pointed out.
Article no. 403: PDF 
Electron temperature determination of bismuth containing electrodelless light sources during self-modulation regime
M. ZINGE, Z. GAVARE, E. BOGANS, A. SKUDRA, A. FRIDMAN
Rom. Rep. Phys. 71, 404 (2019)
Abstract. In this work we estimate electron temperature in bismuth containing light sources in self-modulation regime. The electron-impact excitation rate coefficients were used in modified Arrhenius form. For the electron temperature determination semilogarithmic plot method together with intensity distribution of Ar spectral lines were used. The experiment results showed that electron temperature in high frequency electrodeless plasma values were around 0.4 eV in maximum phase and 0.6–0.7 eV in minimum phase of the self-modulation regime.
Article no. 404: PDF 
Low-pressure plasma synthesis of nanostructured coatings
O. KYLIAN
Rom. Rep. Phys. 71, 405 (2019)
Abstract. Strategy that enables production of nanostructured surfaces is presented. Investigated method is a two-step process based on overcoating of nanoparticles produced by a gas aggregation source by thin film of magnetron sputtered polytetrafluoroethylene. It is shown that surfaces with spatially nonhomogeneous wettability may be produced in this way.
Article no. 405: PDF 
High voltage pulses circuit for generating a plasma plume at atmospheric pressure
O. S. STOICAN
Rom. Rep. Phys. 71, 406 (2019)
Abstract. Study of an atmospheric pressure plasma generator driven by a particular electrical circuit is presented. Electrical circuit consists of a high voltage pulses generator and a common dc high voltage source, parallel connected. The present work was focused to the enhancement of the high voltage pulses production. A method to optimize its operation has been devised.
Article no. 406: PDF 
 
CONDENSED AND SOFT MATTER PHYSICS
 
The propagation of two-dimensional extremely short optical pulses in silicon nanotubes with relaxation and amplification
N.N. KONOBEEVA, M.B. BELONENKO
Rom. Rep. Phys. 71, 501 (2019)
Abstract. We consider the wave equation for an electromagnetic field, which propagates in silicone nanotubes. The processes of damping and amplification are taken into account within the framework of the "phenomenological approach". Also, we study the effects observed when the initial pulse shape, in the form of either a Gaussian beam or an Airy beam, changes.
Article no. 501: PDF 
Characterization of precipitation in 2000 series aluminium alloys using neutron diffraction, SANS and SEM methods
GIZO BOKUCHAVA, YULIA GORSHKOVA, RICARDO FERNANDEZ, GASPAR GONZALEZ-DONCEL, GIOVANNI BRUNO
Rom. Rep. Phys. 71, 502 (2019)
Abstract. Combination of high-resolution time-of-flight (TOF) neutron diffraction, scanning electron microscopy (SEM) and small angle neutron scattering (SANS) have been used to study hardening precipitation in 2014Al and 2124Al alloys. Neutron diffraction experiment revealed presence of tetragonal CuAl2 phase (θ/θ' precipitates) in 2014Al alloy and orthorhombic CuMgAl2 phase (S-precipitates) in 2124Al alloy. SEM image analysis revealed that the θ/θ'-precipitates have platelet morphology while the S-precipitates exhibit rod-like shapes. From SANS data analysis the characteristic dimensions of precipitate particles and their polydisperse distributions were estimated.
Article no. 502: PDF 
Nano-porous coatings for gas retention studies
C. RUSET, E. GRIGORE, M. RASINSKI, E. FORTUNA, J. GRZONKA, M. GHERENDI, C. LUCULESCU, N.P. BARRADAS, E. ALVES, A. HAKOLA
Rom. Rep. Phys. 71, 503 (2019)
Abstract. One way to produce coatings with high gas retaining capability is to manipulate their structure towards a nano-porous one. Combined Magnetron Sputtering and Ion Implantation (CMSII) technique was used to produce pores of 1-10 nm in tungsten layers of about 1 μm in thickness. STEM, EDX, RBS, TDS and GDOES techniques were used for analyses of these layers. By heating the layer at 950 °C the pores size increased up to 30 nm. The total amount of Ar retained in these layers was 3.9·1020 atoms/m2 while in compact W coating of the same thickness only 2.7·1019 atoms/m2 it was found.
Article no. 503: PDF 
 
ENVIRONMENTAL AND EARTH PHYSICS
Disinfection from pine seeds contaminated with Fusarium Circinatum Nirenberg & O’Donnell using non-thermal plasma treatment
B. SERA, A. ZAHORANOVA, H. BUJDAKOVA, M. SERY
Rom. Rep. Phys. 71, 701 (2019)
Abstract. Fusarium circinatum is a quarantine pest of trees that causes pitch canker disease in many pine species. The aim of this study was to test non-thermal, environmentally friendly plasma treatment for the disinfection of seed surfaces infected by F. circinatum. Inoculated seeds were plasma treated using a Diffuse Coplanar Surface Barrier Discharge apparatus working at atmospheric pressure and room temperature. The exposure times of the plasma treatment were: 0 s, 5 s, 10 s, 60 s, 180 s, and 300 s. Data analysis was performed with ANOVA test. A reduction of seedborne pathogens (14–100%) and seed germination (0-6.67%) was documented at the end of seed cultivation. Inoculated seeds remained free of mold infection for 12 days of cultivation on an agar surface in Petri dishes already after a short plasma treatment time of 60 seconds. Inoculated seeds treated for 5 s and 10 s had smaller seed germination (5.33% and 6.67% respectively) in comparison to samples without inoculation and plasma treatment (16%). Inoculated seeds treated for 60 or more seconds did not germinate. This work demonstrated the possibility of using plasma treatment against the dangerous F. circinatum fungus as a type of physical disinfectant method. The following research strategy will deal with the methodology elaboration of seed disinfection which would keep the seeds viable.
Article no. 701: PDF 
Main active faults from the Eastern part of Romania (Dobrogea and Black Sea). Part I: longitudinal faults system
M.DIACONESCU, A. CRAIU, D. TOMA-DANILA, G.M. CRAIU
Rom. Rep. Phys. 71, 702 (2019)
Abstract. The main goal of this article is to decode the seismicity of the Eastern part of Romania and its correlations with the active tectonic (faults systems) present in the area, in order to create a specific database for seismic hazard assessment process and also describing the faults in SHARE manner and thus to fill a gap in the project. By analyzing the active faults from onshore and offshore of Black Sea coast we contribute to the effort of assessing the tsunamigenic potential of the Black Sea areal. Our purpose is to describe the active faults, with the aim of determining geometrical and seismological parameters, using Individual Seismogenic Sources. So, we highlight ten active faults from which four faults present the tsunamigenic potential, with local effects, as follows: Sf. Gheorghe Fault, Peceneaga - Camena Fault, Capidava-Ovidiu Fault and Costinesti Fault.
Article no. 702: PDF 
Seismic warning time for Vrancea earthquakes in three large dams sites situated in the Eastern part of Romania
A. MARMUREANU, I.A. MOLDOVAN, V.E. TOADER, GH. MARMUREANU, C. IONESCU
Rom. Rep. Phys. 71, 703 (2019)
Abstract. The seismic early warning system (SEWS) in Romania uses a mixed regional approach, based on the national seismic network and local sensors to obtain a fast location for recorded events and estimate the actual earthquake magnitude. In order to assess the performance of the alarm system for the 3 dams studied in this paper: Poiana Uzului - Bacau County, Rapa Albastra - Vaslui County and Izvorul Muntelui - Neamt County, there have been made offline simulations on seismic recordings for estimating the actual warning time in the three locations mentioned above. There have been chosen four representative earthquakes ML > 5.0, occurred in the last years in Vrancea seismic zone, for which there are enough records, one crustal from 23rd of September 2017 (ML = 5.7) and three subcrustal from: 22nd November 2016 (ML = 5.8), 27th December 2016 (ML = 5.8) and 2nd February 2017 (ML = 5.0).
Article no. 703: PDF 
Monitoring the Black Sea natural hazards using new technology and equipment
R. PARTHENIU, C. GHITA, T. VICTORIN, E. NASTASE, A. MUNTEAN, E. MURAT, I.A. MOLDOVAN, C. IONESCU
Rom. Rep. Phys. 71, 704 (2019)
Abstract. The Black Sea is prone area to natural hazards: earthquakes, tsunamis, storms, strong winds and other meteorological conditions. In order to monitor them, the National Institute for Earth Physics (NIEP) has installed different types of equipments, implemented into a system that can send warnings for tsunamis and earthquakes generated in the Black Sea. As part of the routine monitoring, the first tsunami early-warning system in the Black Sea was accomplished in 2013, providing sea level and seismic data exchange with the Black Sea surrounding countries. A number of 3 sea level monitoring stations and 7 GPS/GNSS stations are installed in different locations in Dobrogea area. An infrasound micro-barometer, a meteorological station and a vertical electric field monitor were also installed. Various parameters are measured, from water level variations to temperature, wind speed and direction, precipitations, etc. In order to centralize all data, a web portal for worldwide and regional tsunami monitoring was developed (tsunami.infp.ro), with a focus on the Black Sea. Some other objectives of NIEP are to continue monitoring the natural hazards triggered in the area, to increase regional and international collaboration, and to add seismic, GPS/GNSS, sea level and other equipment to the existing network.
Article no. 704: PDF 
 
PHYSICS EDUCATION
 
Setup for quantum cascade lasers characterisation using the LabVIEW programming environment
P. BLEOTU, L. MIHAI, D. SPOREA
Rom. Rep. Phys. 71, 901 (2019)
Abstract. The paper presents the implementation of a setup for the evaluation of mid-IR quantum cascade lasers using LabVIEW. Opto-electronic characteristics are monitored as function of current and temperature: voltage-current, emitted optical power-current, wavelength-current, optical spectrum-current, laser emitted beam. Temporal stability of the wavelength and optical power can be also investigated.
Article no. 901: PDF 

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