Volume 69, Number 4, 2017
 
THEORETICAL, MATHEMATICAL, AND COMPUTATIONAL PHYSICS
 
Anomalous diffusion models with general fractional derivatives within the kernels of the extended Mittag-Leffler type functions
X.-J. YANG, J.A. TENREIRO MACHADO, D. BALEANU
Rom. Rep. Phys. 69, 115 (2017)
Abstract. This paper addresses the new general fractional derivatives (GFDs) involving the kernels of the extended Mittag-Leffler type functions (MLFs). With the aid of the GFDs in the MLF kernels, the mathematical models for the anomalous diffusion of fractional order are analyzed and discussed. The proposed formulations are also used to describe complex phenomena that occur in heat transfer.
Article no. 115: PDF 
 
A resonant coupling of a localized harmonic oscillator to an elastic medium
B.F. APOSTOL
Rom. Rep. Phys. 69, 116 (2017)
Abstract. The motion a point harmonic oscillator coupled to a homogeneous elastic medium and localized either on the medium's surface or embedded in the medium is analzyed. Two new elements are introduced, one regarding the reaction of the oscillator upon the medium and another concerning a coupling function. The present analysis is meant to be relevant for the effects a seismic motion may have upon a localized structure, either natural or man-built. It is shown that the reaction of the oscillator modifies its inertia, which in turn leads to a change in the oscillator's eigenfrequency; this change is controlled by the coupling function. The present treatment opens the way of introducing new, more realistic features in analyzing the effect of the seismic motion upon localized structures, in particular the non-linear features of the coupling of the structure with its local site's motion.
Article no. 116: PDF 
 
Generalized master equation, Bohr's model, and multipoles on fractals
S. ASHRAFI, A. KHALILI GOLMANKHANEH, D. BALEANU
Rom. Rep. Phys. 69, 117 (2017)
Abstract. In this manuscript, we extend the Fα-calculus by suggesting theorems analogous to the Green's and the Stokes' ones. Utilizing the Fα-calculus, the classical multipole moments are generalized to fractal distributions. In addition, the generalized model for the Bohr's energy loss involving heavy charged particles is given.
Article no. 117: PDF 
 
New general fractional-order rheological models with kernels of Mittag-Leffler functions
XIAO-JUN YANG
Rom. Rep. Phys. 69, 118 (2017)
Abstract. In this paper, we consider new fractional-order Maxwell and Voigt models within the framework of the general fractional derivatives (GFDs). The operators are considered in the sense of Liouville-Caputo and Riemann-Liouville types GFDs involving the kernels of the Mittag-Leffler functions. The creep and relaxation characteristics for the fractional-order models are also discussed in detail. The formulations are proposed as useful tools to describe the complex behaviors of the general fractional-order viscoelasticity with memory effect.
Article no. 118: PDF 
 
Composite Bernoulli-Laguerre collocation method for a class of hyperbolic telegraph-type equations
E.H. DOHA, R.M. HAFEZ, M.A. ABDELKAWY, S.S. EZZ-ELDIEN, T.M. TAHA, M.A. ZAKY, A.Z.M. AMIN, A.A. EL-KALAAWY, D. BALEANU
Rom. Rep. Phys. 69, 119 (2017)
Abstract. In this work, we introduce an efficient Bernoulli-Laguerre collocation method for solving a class of hyperbolic telegraph-type equations in one dimension. Bernoulli and Laguerre polynomials and their properties are utilized to reduce the aforementioned problems to systems of algebraic equations. The proposed collocation method, both in spatial and temporal discretizations, is successfully developed to handle the two-dimensional case. In order to highlight the effectiveness of our approachs, several numerical examples are given. The approximation techniques and results developed in this paper are appropriate for many other problems on multiple-dimensional domains, which are not of standard types.
Article no. 119: PDF 
 
Investigation of the nucleation process in a bi-component system using Monte Carlo simulation
C. BERLIC, C. MIRON
Rom. Rep. Phys. 69, 120 (2017)
Abstract. Using Monte Carlo simulations, we investigated the instantaneous nucleation of polymeric blends and we found that the kinetic is well described by the Avrami equation. We calculated the overall crystallization rate constants and the Avrami indices and we made a statistics of the radii of the generated spherulites.
Article no. 120: PDF 
 
 
PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
 
A purely quark Lagrangian from QCD
A.H. FARIBORZ, R. JORA
Rom. Rep. Phys. 69, 302 (2017)
Abstract. We present a method for determining a purely quark Lagrangian by mocking up the QCD partition function for large gauge couplings g. The resulting effective theory displays all the symmetries of low energy QCD and can be potentially used to explore hadron properties.
Article no. 302: PDF 
 
 
OPTICS AND PHOTONICS, PLASMA, LASER AND BEAM PHYSICS
 
Spatial and temporal dynamics of few-cycle laser beams in dispersive media
L. IONEL, C. MATEI, I. ANGHEL
Rom. Rep. Phys. 69, 412 (2017)
Abstract. The spatio-temporal equivalence s= ct, where c is the speed of light and s is the spatial extent of ultra-short laser pulses of duration t is investigated after propagation through dispersive media using 2D modeling of the electromagnetic pulses. The spatial extension of the ultra-short pulses has been quantified after propagation through different media in the presence of pulse duration variation. The result is explained in correspondence with the extension of the Rayleigh range and it is relevant for a wide range of ultra-short pulse laser applications where tightly-focused few-cycle pulses (TFP) are required.
Article no. 412: PDF 
 
 
CONDENSED AND SOFT MATTER PHYSICS
 
Properties of samarium doped hydroxyapatite thin films deposited by evaporation
S.L. ICONARU, G.A. STANCIU, R. HRISTU, R.V. GHITA
Rom. Rep. Phys. 69, 508 (2017)
Abstract. The aim of this study was to investigate the antifungal activity of samarium doped hydroxyapatite (Ca10-xSmx(PO4)6(OH)2, xSm = 0.02 and xSm = 0.05) layers deposited on titanium substrate by a thermal evaporation technique. The morphology of the samarium doped hydroxyapatite layers deposited on a Ti (Ti-Sm:HAp_2 and Ti-Sm:HAp_5) substrate were investigated using scanning electron microscopy (SEM). The antifungal activity of the Sm:HAp layers was assessed using Candida albicans ATCC 10231 fungal strain. The biofilm development of the C. albicans on the Sm:HAp layers was investigated by confocal laser scanning microscopy (CLSM). The results have evidenced a significant inhibition of the fungal cells adherence and biofilm development on the Sm:HAp layers.
Article no. 508: PDF 
 
Electronic properties of o-doped porous graphene and biphenylene carbon: A density functional theory study
R. MAJIDI, M. SAADAT, S. DAVOUDIL
Rom. Rep. Phys. 69, 509 (2017)
Abstract. We have used density functional theory to study the electronic properties of O-doped porous graphene and O-doped biphenylene carbon. The porous graphene is an insulator, while the biphenylene carbon shows semiconducting property. It was found that oxygen doping has a considerable effect on the electronic properties of porous graphene and biphenylene carbon sheets. These sheets become n-type semiconductors in the presence of oxygen impurity. The energy band gap was decreased due to the presence of oxygen impurity.
Article no. 509: PDF 
 
 
BIOPHYSICS AND MEDICAL PHYSICS
 
Chlorophyll A-labelled artificial lipid membranes exposed to photo-oxidative stress. Spectral studies
S.M. PETROVIC, M.E. BARBINTA-PATRASCU, S.R. SAVIC, J.B. ZVEZDANOVIC
Rom. Rep. Phys. 69, 612 (2017)
Abstract. The chlorophyll stability in biomimetic environment is the precondition for its potential application in various fields of science and technology. Its unique role, based on the specific and very diverse chemical reactivity, justifies its use in industrial technology, pharmaceutical, food and cosmetic industry, but also in medicine. In this work, two types of liposomes were prepared from saturated (dipalmitoyl phosphatidylcholine) and unsaturated (PHOSPHOLIPON 90®) lipids. The artificial lipid membranes were labeled with a natural photopigment-chlorophyll a (Chla). The stability of Chla-based liposomes to in vitro induced oxidative stress by visible and UVB irradiation was examined by UV-Vis absorption spectra, and by monitoring two kind of lipid peroxidation biomarkers (conjugated dienes and TBA-MDA assay) which were quantified in order to evaluate the photodamage degree of artificial lipid membranes. Chla proved to be an effective spectral sensor to detect any damages induced by visible light and UVB irradiation on liposomes. After applied Vis/UVB radiation, Chla-liposomes suffered photodegradation which was more pronounced under UVB stress. The investigations demonstrated a closely connection between lipid peroxidation and chlorophyll degradation. The deterioration was higher in the case of biomimetic membranes made of unsaturated lipids exposed to photo-oxidative stress because of presence of double bonds in lipid molecules that decisively contribute to the formation of lipid radicals. Based on these results it can be concluded that the chlorophyll behavior mechanism under the photo-oxidative stress is of crucial importance for further bio-applications.
Article no. 612: PDF 
 
 
ENVIRONMENTAL AND EARTH PHYSICS
 
Gross alpha, gross beta and gamma activities in bottled natural mineral water from Romania
I. RADULESCU, M.R. CALIN, I. ION, A.C. ION, L. CAPRA, C.A. SIMION
Rom. Rep. Phys. 69, 710 (2017)
Abstract. The activity concentrations of 238U, 226Ra and 232Th were analysed in eleven natural mineral waters sources, non-carbonated ones from Northern Romania. The samples were collected for a period of three years. The waters originate from a volcanic aquifer containing carbonate rocks. It was found that the concentration of uranium isotope 238U varied in the ranges 0.07-0.48 Bq L-1. The activity ratio between uranium isotope 238U and radium isotope 226Ra was between 0.03-1.05. The calculated doses for the analysed samples are in the range 8.84-40.75 μSv/year, with an average value of 20.08 μSv/year, where the reference level of 100 μS/year is the committed effective dose recommended by WHO and the EU Council.
Article no. 710: PDF 
 
Assessment of metals level in several meat products obtained through conventional and traditional methods
I. MANEA, L. MANEA, C. RADULESCU, I.D. DULAMA, S. TEODORESCU, R.M. STIRBESCU, E.D. CHELARESCU, I.A. BUCURICA
Rom. Rep. Phys. 69, 711 (2017)
Abstract. The aim of this study was to assess the content of several heavy metals from meat products (e.g. sausages, salami, neck, muscle, and ribs) obtained either by cold or hot smoking or pasteurization, considering that these metallic elements are toxicants for human health. Their toxicity depends on several factors including dose, route of preparation and type of meat. Because of their high degree of toxicity, if they are present in meat products, nine metals, including Cr, Pb, Cd, Co, Ni, Mn, Cu, Fe, and Zn, were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique of high precision and sensitivity. The first four elements are classified as human carcinogens according with the International Agency for Research of Cancer (IARC). In this research it was obtained a lower content of metals in smoked meat products (i.e. muscle, neck, ribs, pulp) and a higher metals content in product without structure (minced meat). The order of the elements in meat products and their concentration ranges in mg/kg d.w. was Fe (11.748-26.131) > Zn (4.282-11.586) > Mn (0.965-5.433) > Cu (1.987-4.154) > Cr (1.119-3.295) > Ni (1.115-2.170) > Pb (0.242-0.477) > Co (0.204-0.301) > Cd (0.091- 0.095). Therefore, each metal which has well-established features and physicochemical properties present a specific toxicology within meat products, especially when their procedure of obtaining was not properly conducted.
Article no. 711: PDF 
 
Ultrahigh frequency-low power electromagnetic field impact on physiological parameters of two types of cereals
M. RACUCIU, C. IFTODE, S. MICLAUS
Rom. Rep. Phys. 69, 712 (2017)
Abstract. The aim of this study was to investigate the impact of mobile communication low power radiofrequency radiations on physiological and growth parameters of two types of cereal plantlets developed from exposed seeds (Zea mays and Hordeum vulgare) in controlled conditions to continuous waves to 850 MHz and 1800 MHz. Exposure of seeds was realized inside a transverse electromagnetic (TEM) cell, for different exposure durations between 0 and 6 hours, and then let to germinate. Computational dosimetry was applied for all experimental cases. Decrease in the photosynthetic pigments levels was found for both frequencies and plant species, respectively. Also, opposite influence was revealed upon level of total nucleic acids depending on plant species and frequency of electromagnetic field.
Article no. 712: PDF 
 
Control of surface properties of charged polysulfone/cellulose acetate phthalate films with implications in water treatment
M.D. ONOFREI, A. FILIMON, I. STOICA
Rom. Rep. Phys. 69, 713 (2017)
Abstract. Development of materials based on charged polysulfones were carried out as a result of their applications in membrane technology, imposing specific forms and sizes, according to the application area. Composite membranes based on quaternized polysulfones with controllable porosity and hydrophilicity degree were achieved by blending with a hydrophilic polymer, cellulose acetate phthalate. The cumulative effects of the cellulose acetate phthalate composition, charge density of polyelectrolytes, as well as the history of the formed films provide the controlling surface properties and are responsible for performance properties of the final membranes. Thus, the embedding of cellulose acetate phthalate at polysulfonic matrix improves the surface properties, surface tension parameters evaluated by contact angle measurements and also, modifies the polymer structure at morphological level, surface mechanical properties determined by specific atomic force microscopy experiments, force-distance spectroscopy DFL. The obtained results highlighted that the adhesion force values are similar to the wettability characteristics of the surface, quantified by polar component values of the surface tension, and are important in designing composites membranes used in water treatment.
Article no. 713: PDF 
 
Modeling and simulation of radiological dispersion device events
D.V. VAMANU, V.T. ACASANDREI
Rom. Rep. Phys. 69, 714 (2017)
Abstract. The paper delves into the radiological emergencies consecutive to the hypothetical use of Radiological Dispersion Devices (RDD) - a new class of paraphernalia believed to make a way in the arsenal of contemporary terrorism - bearing in particular on the modeling, simulation and visualization of the physical phenomenology involved, the environmental contamination, health effects and response measures expected. The value of dedicated software tools in a pro-active, anticipative preparedness for confronting such disruptive events and mitigate consequences is emphasized and illustrated using as reference the framework of the international exercise Bab-al-Maghrib, November, 2013 convened and held under the aegis of the International Atomic Energy Agency, IAEA.
Article no. 714: PDF 
 
 
APPLIED AND INTERDISCIPLINARY PHYSICS
 
Bio-retexturing in limestone used in the built heritage of Malta
LINO BIANCO
Rom. Rep. Phys. 69, 802 (2017)
Abstract. The paper addresses bio-retexturing within the Lower Globigerina Limestone, the limestone used in the construction of the island's built cultural heritage which dates back to the Neolithic Period. Samples from the host sedimentary layer and burrow infills were analysed to establish the varying petrological, geochemical and mineralogical charcateristics. Petrological examination in thin section indicates that burrowing introduces unlithified sediment in the primary depositional fabric. XRF and XRD indicate that the mineralogy of the infill is qualitatively and quantitatively different from the host rock, often richer in goethite which accounts for its dark yellow ochre colour. Bio-retexturing introduces predominantly non-carbonate rich infill and modifies the original sediment; due to the intra-particle cement, it transforms its permeability and porosity.
Article no. 802: PDF 
 
Proposal for a new type of accelerator for electrons and protons
NICOLAE VERGA, MADALINA CROITORU, FLOREA SCARLAT
Rom. Rep. Phys. 69, 803 (2017)
Abstract. A new laser-based acceleration structure for protons, with characteristics appropriate for the radio therapy is proposed in the present work. The structure is designed in two stages of acceleration - the first one accelerates electrons to GeV energies and the second one uses these electrons in order to accelerate protons in the hundreds of MeV range. It uses commercial available pulsed lasers and it is expected to have the geometrical sizes that fit into a usual oncological treatment room. The accelerated proton beams have energies of hundreds of MeV with a medium to large spread, a high repetition rate, geometrical dimensions and emittance adequate for a small size medical accelerator facility. The present proposal is mainly an attempt coming from the medical community to bring into the attention of accelerator scientists the huge need for small size treatment accelerators, nowadays feasible grace to the last decades progress in laser technologies.
Article no. 803: PDF 
 
Artificial enhancement of fill factor and resolution for monochrome CMOS sensor array
T. VASILE, V. DAMIAN, M. VASILE, D. COLTUC
Rom. Rep. Phys. 69, 804 (2017)
Abstract. In this paper we present a piezoelectric method to increase simultaneously both resolution and fill factor of a conventional CMOS sensor array. For this improvement we scan a photo lens image plane with the surface of a commercial CMOS sensor, placed perpendicular on the system optical axis at 45 degrees to the horizontal. The method takes advantage of the image sensor inter-photosite distance and its higher diagonal resolution. For our experiment we use two images of the same scene, distanced from each other, on the horizontal axis of the image plane, with half of a diagonal length of an effective sensor photosite area. The images are combined, using a pixel interlacing method, into one new image with higher resolution and fill factor.
Article no. 804: PDF 
 
 
PHYSICS EDUCATION
 
Solving a conundrum in beta-decay spectroscopy experimentation
IHAB H. NAEIM, S. ABDALLA, J. BATLE, A. FAROUK
Rom. Rep. Phys. 69, 905 (2017)
Abstract. Experiment at ion on beta spectroscopy introduces the student into the field of radioactive decay, the Fermi theory, special relativity and the weak interaction. With the help of a simple surface barrier detector-spectrometer, the continuous spectra of some beta-ray emitters have to be measured and interpreted. Here we show how students react to an unexplained difference between measurement and theory, which leads them to speculate in the end about each possible aspect that may account for it.
Article no. 905: PDF 
 

This is an electronic version of Volume 69 Number 4 2017
 
   
 
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