Volume 71, Number 3, 2019
 
THEORETICAL, MATHEMATICAL, AND COMPUTATIONAL PHYSICS
 
Breather solutions for a six-component AKNS system with a negative flow
JING SHEN, XIANGUO GENG, BO XUE, HUAN LIU
Rom. Rep. Phys. 71, 107 (2019)
Abstract. A six-component AKNS system with a negative flow associated with the 4×4 matrix spectral problem is proposed, which can be reduced to the sine-Gordon equation. Darboux transformation for this system is constructed by setting a restrictive condition on two spectral functions. As an application, three breather type solutions for this system are obtained, including the space-time periodic solution, Kuznetsov-Ma breather solution and Akhmediev breather solution. Specifically, we show a kind of Akhmediev breather composed of bright-dark lump waves.
Article no. 107: PDF 
On the predictability of the final state in a ring of Kuramoto rotators
K. DENES, B. SANDOR, Z. NEDA
Rom. Rep. Phys. 71, 108 (2019)
Abstract. Emergence of order in randomly initialized systems of locally coupled identical Kuramoto rotators is studied. Depending on the system's initialization different types of collective oscillation modes (dynamically stationary states) can develop. Following the dynamics of such oscillator ensembles the emergent collective mode can be predicted after a certain time interval. For large enough systems, this prediction time is scaling with the square of the system's size.
Article no. 108: PDF 
 
ATOMIC, MOLECULAR, AND NUCLEAR PHYSICS
 
Source commissioning of the ELIGANT-GG setup for γ-ray coincidence measurements at ELI-NP
P.-A. SODERSTROM, L. CAPPONI, E. ACIKSOZ, D.L. BALABANSKI, G.L. GUARDO, D. LATTUADA, C. MATEI, D. NICHITA, A. PAPPALARDO, T. PETRUSE, G. V. TURTURICA
Rom. Rep. Phys. 71, 206 (2019)
Abstract. The design and commissioning of a new detector array within the ELIGANT set-up, with the aim of measuring weak second and third order γ-ray emitting quantum-electrodynamical processes, is reported. This ELIGANT-GG set-up is discussed in terms of technical specifications, time resolution, and efficiency of the set-up itself. The long-term stability and linearity of the detectors are investigated as important factors for the feasability of long-running experiments. Furthermore, the capabilility of the set-up for measuring angular distributions is shown. Finally, it is demonstrated that indeed very rare γ-coincidence signals with a relative branching as low as 10-6 can be measured.
Article no. 206: PDF 
Angular and spatial distributions of protons channeled in a bent and radially deformed single-wall boron-nitride nanotubes
D. BORKA, S.M.D. GALIJAS
Rom. Rep. Phys. 71, 207 (2019)
Abstract. This study is devoted to the angular and spatial distribution of protons channeling through a bent and radially deformed single-wall boron-nitride nanotubes (SWBNNTs). These nanotubes are more thermal and chemical stable then carbon nanotubes, and they are good candidates for future channeling experiments. This investigation is continuation of our previous study [1, 2] and now we investigate channeling properties of SWBNNTs as a function of the very realistic effects: bending angle of nanotube and its radial deformation. For the first time we presented here investigation of these effects with boron-nitride nanotubes and combination of both effect. The angular and spatial distributions of channeled protons were generated using the Moliere's expression for the continuum potential of the SWBNNT’s atoms and computer simulation method. We also calculate the total yield of protons channeled in the nanotubes as a function of the bending angle. We demonstrate that varying bending angle and taking into account radial deformation we can get a significant rearrangement of the propagating protons within the boron-nitride nanotube. This investigation may be very useful to give us detailed information on the relevant interaction potentials inside SWBNNTs and for creating nanosized proton beams to be used in different applications in medicine and materials science.
Article no. 207: PDF 
Radiological protection calculations of the ELI-NP 10 PW laser experimental area using FLUKA code
M.A. POPOVICI, F. NEGOITA, I.O. MITU, R. VASILACHE, D. BUZATU
Rom. Rep. Phys. 71, 208 (2019)
Abstract. The high levels of ionizing radiation expected at most of the experimental areas of the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility in Bucharest are challenging from a radiation protection point of view. FLUKA Monte Carlo code is a widely used tool allowing to estimate dose contributions of the complex radiation fields and the transport of the radiation through the bulk shielding. In this paper we present the results of a shielding study for the experimental area E1, the site of the laser driven nuclear physics experiments. Updated source terms were used and ambient dose equivalent rates were calculated to check the compliance with the design target dose values and to identify critical dose locations. To reduce radiation levels for neighbouring areas below the required limits, an optimized beam dump and local shielding were proposed.
Article no. 208: PDF 
Tritium standardization by the LSC-TDCR method and participation at international comparisons
A. ANTOHE, M. SAHAGIA, PH. CASSETTE, A. LUCA, M.-R. IOAN
Rom. Rep. Phys. 71, 209 (2019)
Abstract. This paper presents the results obtained in the standardization of 3H, by using the LSC-TDCR method at IFIN-HH. The improvements regarding preparation and measurement of samples, processing and analysis of experimental data finalized by reporting the results (activity or activity concentration of a solution and its associated combined standard uncertainty) are described. The method and basic results of a bilateral (Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), Romania with the Laboratoire National d'Essais – Commissariat a l'Energie Atomique et Energies Alternatives, Laboratoire National Henri Becquerel (LNE-CEA, LIST, LNHB), France) and two 3H international comparisons, involving our laboratory, are presented: (i) CCRI(II)-K2.H-3, 2009, key comparison and (ii) the supplementary comparison CCRI(II)-S12.H-3, 2016. The TDCR06b software was used in case (i) and the improved TDCR07c in case (ii). The recommendations from the recent papers related to the preparation of samples, measurement and processing of the primary data, with special attention paid to the influence of kB parameter and to the involved statistical model, were applied carefully.
Article no. 209: PDF 
 
OPTICS AND PHOTONICS, PLASMA, LASER AND BEAM PHYSICS
 
Defect modes supported by parity-time-symmetric triangular optical lattices with self-defocusing Kerr nonlinearity
HONG WANG, XIAOPING REN, DUMITRU MIHALACHE, YUANHANG WENG, JING HUANG, YINGJI HE
Rom. Rep. Phys. 71, 411 (2019)
Abstract. The existence, stability, and evolution dynamics of fundamental and vortex solitons in parity-time-symmetric triangular optical lattices with self-defocusing Kerr (cubic) nonlinearities and single-site defects are studied. It is shown that the defect depth has a great effect on solitons' properties. For fundamental defect solitons, the existence regions shrink sharply with the decrease of the defect depth. Their stability is in accordance with the anti-Vakhitov-Kolokolov criterion. For vortex defect solitons, the positive defect plays a stabilizing role on solitons. The influence of the gain/loss component on the key characteristics of defect solitons is also presented.
Article no. 411: PDF 
 
CONDENSED AND SOFT MATTER PHYSICS
 
Properties of C-W-Mg thin films deposited by sequential PLD in hydrogen and nitrogen atmosphere
L.N. DUMITRESCU, A. MOLDOVAN, A. BONCIU, V. ION, D. COLCEAG, M. DINESCU
Rom. Rep. Phys. 71, 506 (2019)
Abstract. One of the most critical issues in the operation of tokamak reactors is the re-deposition of the different materials from various parts of the reactor. The re-deposition processes affect the lifetime of the reactor components, contributing to the contamination of the plasma and its fast extinction. To this end, the aim of this work is to investigate some of the properties of mixed materials based on C-W-Mg in the form of thin films, and the effects of exposure to nitrogen, argon and hydrogen plasmas on these properties. The motivation of our study results from practical considerations related to materials used in reactors: for reactor wall coatings candidate materials are beryllium (Be) and graphite (C), whereas tungsten (W) is considered for the divertor. In our reported experiments, due to its high toxicity during handling, Be was replaced by magnesium (Mg), which possesses similar properties concerning the interaction of the walls elements with the fusion plasma. The surface morphology of the PLD deposited thin films was studied by Scanning Electron Microscopy (SEM). The thicknesses were investigated by spectroscopic ellipsometry (SE). The composition was assessed by energy dispersive X-ray spectroscopy (EDX) and secondary ion mass spectrometry (SIMS).
Article no. 506: PDF 
ATR-FTIR versus Raman spectroscopy used for structural analyses of the iron oxide nanoparticles
M. RACUCIU, S. OANCEA
Rom. Rep. Phys. 71, 507 (2019)
Abstract. Hereby we report the preparation of water colloidal solution of magnetic IONPs coated using perchloric acid, by application of co-precipitation method. ATR-FTIR and Raman spectroscopic techniques were used to investigate the IONPs' structure. The Raman pattern revealed that magnetic core of IONPs is given by the coexistence of magnetite and maghemite phases. Transmission electron microscopy analysis showed that IONPs are mostly spherical with the average physical diameter of 10.42 nm. Based on magnetic measurements data, the obtained average magnetic diameter was 7.12 nm. We supposed that a partial oxidation of magnetite to maghemite have been produced during the preparation of IONPs.
Article no. 507: PDF 
 
ENVIRONMENTAL AND EARTH PHYSICS
 
Estimation of Ångström atmospheric turbidity over Bucharest, Romania
G. MANOLACHE, G. IORGA, S. STEFAN
Rom. Rep. Phys. 71, 711 (2019)
Abstract. The aim of this paper is to investigate the air turbidity in the urban environment. The turbidity is determined at three sampling sites covering different types of pollution in Bucharest area during 1st of June 2014 to 31st of May 2015. The optical parameters used in computing Ångström turbidity were determined based on the mass concentration of particulate matter with diameters smaller than 10 μm (PM10) measured at urban stations Bucurestii Noi and Cercul Militar and at the suburban station Magurele. The PM10 mass concentrations were used as input data for OPAC software to compute aerosol optical depth (AOD), Ångström's turbidity coefficient (β) and Ångström exponent (α). Air turbidity was also computed using a parameterization based on solar irradiance at ground level and a parameterization between PM10 and AOD. The comparison between turbidity values obtained from the Ångström equation and the two different parameterizations have shown differences for the three stations due to different type of pollutant, local pollution sources and weather conditions. Linear relationships between Ångström coefficient and Linke factor were established for each site and compared with those for other worldwide climates.
Article no. 711: PDF 
Dispersion model for low wind and atmospheric calm - Part I: description
V. CUCULEANU, A. LUPU, G. GRIGORAS, I. POPESCU, A. TOMA
Rom. Rep. Phys. 71, 712 (2019)
Abstract. A dispersion model is developed for low wind and atmospheric calm. The model takes into account both turbulent diffusion and advection along the wind direction in the case of low wind. It provides one option for calculating the concen- tration in low wind and two options for calm conditions, implements an algorithm for calculating the building effect, and uses the Briggs plume rise equations. The effect of wet deposition and radioactive decay is also considered.
Article no. 712: PDF 
Stationary magnetic field stimulates rice roots growth
M. FLOREZ, J. ALVAREZ, E. MARTINEZ, V. CARBONELL
Rom. Rep. Phys. 71, 713 (2019)
Abstract. Magnetic field is an environmental factor playing an important role in living organisms, although its effect is not well known. An increase of roots and stem length was observed in seeds subjected to a stationary magnetic field. Some authors have explained the close relation of the magnetic field to cell metabolism of plants. This paper is a survey of magnetic fields effects on rice seedling exposed to magnetic field of two induction values, both stronger than the geomagnetic field, for various length of time. Root length was measured on the 3rd, 7th and 10th day after seeding. Magnetically treated seedlings grew longer and heavier than untreated ones. On the 3rd day the length of roots of seedlings chronically exposed to 125 and 250 mT were significantly longer (20.67 and 30.61 mm respectively) than control (9.05 mm). On the 7th day, significant differences were observed for doses D6 (chronically exposed to 125 mT) and D11 (exposed to 250 mT for 24 h) related to controls. On the 10th day, exposed roots were longer and heavier than control roots, but not significantly. In addition, secondary roots of plants chronically exposed to magnetic field were more developed than untreated ones.
Article no. 713: PDF 
Correlations between geomagnetic anomalies recorded at Muntele Rosu Seismic Observatory (Romania) and seismicity of Vrancea zone
A. MIHAI, I.A. MOLDOVAN, V.E. TOADER, M. RADULIAN, A.O. PLACINTA
Rom. Rep. Phys. 71, 714 (2019)
Abstract. In the present paper, a relationship between geomagnetic anomalies recorded at one magnetometer located inside Vrancea seismogenic zone and the occurrence of intermediate earthquakes is examined. To better distinguish the regional anomalies from global geomagnetic storms, the datasets were correlated with the geomagnetic indices taken from NOAA/Space Weather Prediction Center. During five years of investigations (2013–2018), three intermediate depth earthquakes with a moment magnitude Mw larger than 5.0 occurred in the Vrancea zone and were accompanied by significant anomalies on the E-W component of the local geomagnetic field (By) measured at Muntele Rosu (MLR) Observatory. The anomalies recorded at MLR were also analyzed along with the seismic energy distribution, providing good opportunity to distinguish the anomaly morphology, and were correlated with the radon emissions and temperature variations, during the detector operating time, in 2016
Article no. 714: PDF 
Anisotropy of magnetic susceptibility analysis of the Rusca-Tihu volcaniclastic formation (East Carpathians): flow directions recognition
S.A. SORTAN, C.G. PANAIOTU, D. DIMOFTE, R.D. ROBAN, C. NECULA
Rom. Rep. Phys. 71, 715 (2019)
Abstract. This anisotropy of magnetic susceptibility and rockmagnetic study reveals several features about the Upper Miocene pyroclastic deposits of the Călimani Mountains. The general trend of inferred flow directions toward south is compatible with the supposed position of eruption centers. The emplacement temperature of the studied pyroclastic deposits was below 300°C
Article no. 715: PDF 
 
APPLIED AND INTERDISCIPLINARY PHYSICS
 
SEM-EDS as investigation tool for archaeological artifacts - the case of nephrite adornments
P. MEREUTA, B. CONSTANTINESCU, D. CRISTEA-STAN, D. SERBANESCU
Rom. Rep. Phys. 71, 802 (2019)
Abstract. Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-Ray Spectroscopy (EDS) proved to be an efficient tool for analyzing archaeological samples. We illustrate with some Neolithic adornments - pendants, presumed nephrite and jadeite items, to verify if geologists' visual examination is confirmed by EDS elemental composition. SEM-EDS must be complementary to X-Ray Fluorescence (XRF), Proton Induced X-ray Emission (PIXE) or Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) methods.
Article no. 802: PDF 
Archaeometallurgical evaluation of finery using nondestructive methods
I. FIERASCU, R.C. FIERASCU, D.A. MIREA, P. FOTEA, R.F. ANDREI, A. ORTAN
Rom. Rep. Phys. 71, 803 (2019)
Abstract. Throughout the history, the ornaments made to be worn accompanied the human development, representing an important source of information regarding various cultures' habits and technology. As those objects are made from durable materials, we now can evaluate the techniques and materials used to create them. The study of such objects, even though can provide invaluable information, should meet some critical criteria, one of the most important being the non-destructive character of the techniques used. The objects selected for the study represents jewelry from late XIXth century - early XXth century (one yellow-color pendant, manufactured at the end of the XIXth century, one medallion manufactured at the beginning of the XXth century and two roman coins, from the Augustus period and, respectively, republican age, modified and turned into a bracelet part, respectively into a brooch). The objects were studied using exclusively non-destructive techniques: optical microscopy, X-ray fluorescence, X-ray diffraction and Particle-induced X-ray emission, the results leading to conclusions regarding not only the composition of the materials and the presence of corrosion compounds, but also regarding the applicability of different techniques for the study of metallic artifacts. The results revealed some "hidden" characteristics of the samples: two of the samples are plated objects (gilded silver, respectively silver-plated brass), while the other two objects were modified using different alloys than the original pieces.
Article no. 803: PDF 
Archaeometric studies of mural paints from Matia Loggia (Corvins' Castle)
R.M. ION, S. TINCU, N. ION, I.A. BUCURICA, S. TEODORESCU, I.D. DULAMA, R.M. STIRBESCU, A.I. GHEBOIANU, C. RADULESCU, M.L. ION, L. IANCU, R.M. GRIGORESCU
Rom. Rep. Phys. 71, 804 (2019)
Abstract. The analysis of the pigments from the Matia's loggia of Corvins' Castle, have been achieved in this paper in order to collect informations about the composition and weathering/deterioration processes of this mural paint. X-ray diffraction (XRD) correlated with optical microscopy (OM), scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS), have been used for identification and quantification of the main components, in relationship with FTIR and Raman spectrometry and with chromatic parameters, too.
Article no. 804: PDF 
Comparative radiocarbon dating study of individual amino acids isolated from archaeological bone collagen towards bulk collagen
O. GAZA, C.S. TUTA, C.A. SIMION, T.B. SAVA, G.O. SAVA, M. MOLNAR, H. IOVU
Rom. Rep. Phys. 71, 805 (2019)
Abstract. Radiocarbon dating of archaeological bones may sometimes provide erroneous data when 14C contaminants from the surroundings where they were buried in the post-depositional phase or from the environment in storage conditions were not eliminated in the pretreatment stage. To solve this problem, a way out may be the dating of individual amino acids. In this paper, various amino acids isolated from collagen were separated using the high performance liquid chromatography (HPLC) method and subsequently dated by accelerator mass spectrometry (AMS). A comparative study of the data obtained for individual amino acids towards bulk collagen was performed.
Article no. 805: PDF 
 
PHYSICS EDUCATION
 
The smart aquaponics greenhouse - an interdisciplinary educational laborator
DANIELA PANTAZI, SERENELLA DINU, SANDA VOINEA
Rom. Rep. Phys. 71, 902 (2019)
Abstract. The aim of this paper is to develop the ability of the students to address interdisciplinary aspects of everyday life. Thus, we have created a solar powered aquaponics system monitored by Arduino microprocessor. The aquaponics greenhouse is a system that combines conventional aquaculture with hydroponic greenhouse in a symbiotic environment. The greenhouse's monitoring system is composed of several types of sensors and an Arduino Acquisition Plate with a Mega 2560 processor. As a power supply for the water pump and the monitoring system, a 50W monocrystalline panel is used. The students can understand some phenomena of biology, physics and chemistry and can also monitor the processes that occur in the aquaponics system.
Article no. 902: PDF 
Dynamics of the pulsejet engine in vertical motion with linear drag
MIRCEA DOLINEANU, TIBERIUS O. CHECHE
Rom. Rep. Phys. 71, 903 (2019)
Abstract. The momentum conservation law is applied to analyse the kinematics of pulsejet equipped systems in vertical motion in a uniform gravitational field in the presence of linear drag. The model is applied to jetting paralarvae moving in sea water in vertical direction.
Article no. 903: PDF 

This is an electronic version of Volume 71 Number 3 2019
 
   
 
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