Publication Date: 2012
Marine Pollution Bulletin (0025326X)64(9)pp. 1956-1961
The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine 235U, 238U, 232Th, 40K and 137Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of 235U, 238U, 232Th, 40K and 137Cs in sediment samples ranged between 1.01 and 2.87Bq/kg, 11.83 and 22.68Bq/kg, 10.7 and 25.02Bq/kg, 222.89 and 535.07Bq/kg and 0.14 and 2.8Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. © 2012 Elsevier Ltd.
Publication Date: 2009
Marine Pollution Bulletin (0025326X)58(5)pp. 658-662
The determination of activity concentrations of the radioactive elements 238U, 232Th, 40K and 137Cs was performed on grab samples taken from a polluted environment. The samples were sliced into strata from 5 cm depth, dried and ground to sieved through a 170 mesh size prior to the analysis. Activity concentration was quantified using gamma spectroscopy. The results showed that the concentrations of activity in the sediment samples are 177 ± 12.4, 117 ± 11.5, 1085 ± 101.6 and 131 ± 4.8 Bq kg-1 for 238U, 232Th, 40K and 137Cs, respectively. In general, the distribution of activity concentrations along the southern coast of the Caspian Sea area exceeded international limits. The hazard index of the samples was 0.19-0.88, with an average of 0.49. The mean values of radium equivalent activity and dose rate are 176 Bq kg-1 and 63 nGy h-1, respectively. © 2009 Elsevier Ltd. All rights reserved.
Publication Date: 2009
Journal of Physics B: Atomic, Molecular and Optical Physics (13616455)42(7)
In this paper, by extending the Lagrangian of the Huttner-Barnett model an electromagnetic field in a nonhomogeneous and anisotropic magnetodielectric medium is quantized canonically. In this model, Maxwell equations in the medium are obtained and solved using the Green function technique. The noise operators are found and the results are compared with the phenomenological method. © 2009 IOP Publishing Ltd.
Publication Date: 2009
European Physical Journal D (14346060)54(1)pp. 115-118
A canonical relativistic formulation is introduced to quantize electromagnetic field in the presence of a polarizable and magnetizable moving medium. The medium is modeled by a continuum of the second rank antisymmetric tensors in a phenomenological way. The covariant wave equation for the vector potential and the covariant constitutive equation of the medium are obtained as the Euler-Lagrange equations using the Lagrangian of the total system. A fourth rank tensor which couples the electromagnetic field and the medium is introduced. The susceptibility tensor of the medium is obtained in terms of this coupling tensor. The noise polarization tensor is calculated in terms of both the coupling tensor and the ladder operators of the tensors modeling the medium. © EDP Sciences, Societá Italiana di Fisica, Springer-Verlag 2009.
Publication Date: 2008
JOURNAL OF NEUROLOGY (03405354)pp. 78-78
Publication Date: 2015
Nanoscale (20403372)7(26)pp. 11379-11385
We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits. © The Royal Society of Chemistry.
The refuge and its rights are considered as one of the controversial categories and issues of the human rights. In this regard, the Geneva International Convention and the attached protocol can be referred as the most important international document and the most important and valuable measurement criterion related to the refugees. In this research, the rules of Iran and Australia under the Geneva Convention and the attached protocol are compared, that the Iran and Australia's government have joined it. It seems that considering the accession of both Iran and Australia countries to the Geneva Convention, the domestic rules of these countries are perfectly conformed to this international document. Also, it seems that considering the reports of the Australia human rights commission and other defenders' authorities of human rights, the approval of the Australia new rule about prohibition of the arrival of the refugees who arrived by boat illegally on seashore of this country and transferring them to other countries, is contrary to the principle of not returning , that has been mentioned in the related documents.
Publication Date: 2024
Computational Condensed Matter (23522143)39
In this study, the structural, elastic, vibrational, electronic, optical, thermodynamic, and thermoelectric properties of the chalcogenide ternary Y2ZnX4 (Y = In, Ga; X = S, Se) compounds are comprehensively investigated using the pseudopotential plane-wave (PP-PW) and full-potential linearized augmented plane wave (FP-LAPW) methods. The analysis of elastic and vibrational properties reveals the dynamic and mechanical stability of these compounds. The calculated energy band gaps, ranging from 1.47 eV (Ga2ZnSe4) to 2.55 eV (In2ZnS4) in the visible spectrum, decrease as X atoms are substituted with S to Se. All examined compounds demonstrate favorable optical absorption (α > 105 cm−1) in the ultraviolet region. Notably, Ga2ZnSe4 exhibits absorption red-shift towards the visible region at hν = 2.76 eV due to its lower energy band gap, making it a promising candidate for solar cells. The three-dimensional representation of Young's modulus indicates significant deviation from sphericity, revealing anisotropic behavior in all compounds. Pugh's ratio, Poisson's ratio, and Cauchy's pressure analysis suggest ductile behavior in all four chalcogenide ternary compounds. Additionally, all compounds, except In2ZnS4, display auxetic properties. Finally, the calculated thermoelectric properties identify Ga2ZnS4 and In2ZnS4 as promising candidates for high-performance thermoelectric applications, with high Seebeck coefficients of 1848 and 1936 μV/K, respectively, and ZT values approaching unit. © 2024 Elsevier B.V.
Publication Date: 2004
Proceedings of SPIE - The International Society for Optical Engineering (1996756X)5249pp. 249-260
A systematic design method for quasi-symmetrical wide angle systems is presented. The method starts with thin lens predesign of half of the system using most available glasses. The aperture stop position is determined for reducing astigmatism and the system is made symetrical about it for eliminating Coma, Lateral colour and Distortion. Finally the system is optimized using Eikonal software for infinite conjugate.
Publication Date: 2016
Radiation Measurements (13504487)89pp. 14-22
In this study, lithium-tetraborate (LTB) was synthesized by three methods of high-temperature solid state, wet and combustion reactions. Copper was added to pure LTB by solution assisted method, to improve the thermoluminescence (TL) properties. The pellets of LTB were produced using pressing and sintering operations at 850 °C. The synthesized LTB pellets, exposed to the gamma radiation of 60Co source in the dose range of 5-20Gy and glow curves as well as dose-response diagrams were obtained. Ultimately, the effects of different factors on TL behaviors like dopant, crystallite size and particle morphologies were studied. The results show that between pure samples, LTB which synthesized by combustion method has higher TL sensitivity than those of other methods. However, it was seen a weak glow peak for 5Gy, due to the nanocrystalline structure of LTB. This property led to decrease TL intensity at low-doses and postponed saturation at high-doses. Fading of this sample was also less than others and has relatively better reproducibility. Among LTB:Cu pellets which synthesized by the wet reaction showed the higher TL response than others due to the creation of more traps and luminescence centers and had promising properties in the case of dose response linearity and fading. © 2016 Elsevier Ltd. All rights reserved.
Publication Date: 2014
International Journal of Modern Physics E (2183013)(8)
A plasma boundary reconstruction code has been designed by using current filament method to calculate the magnetic flux and consequently plasma boundary in Damavand tokamak. Hence, a computer-based code "The Plasma Boundary Reconstruction Code in Tokamak (PBRCT)" was developed to make a graphical user interface and to speed up the plasma boundary estimation algorithm. All required tools as the plasma boundary and magnetic surface display (MSD), error display, primary conditions and modeling panel as well as a search motor to determine a good position and number of the current filaments to find a precise model have been considered. The core is a 3000 lines Matlab code and the graphical user interface is 10,000 lines in C# language. © 2014 World Scientific Publishing Company.
Publication Date: 2023
2023 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA 2023) (10504729)pp. 12624-12630
With the increasing demand for new healthcare solutions and technologies, such as those resulting from the COVID-19 crisis, and the growing elderly population, exoskeletons for teleoperation are a promising solution for many future medical applications. In this context, we propose two forcesensitive upper-limb exoskeletons for teleoperation, that are characterized by: i) torque-controlled robotic actuators, ii) rigid-body model compensations, and iii) a lightweight design achieved through the use of Bowden cable transmissions and remotely placed actuators. Specifically, we present a semi-active upper-limb exoskeleton for which we demonstrate humandevice interaction control and bilateral teleoperation with forcefeedback, evaluated via simulation, in the lab and over the Internet. We also introduce a design for a future fully-active upper-limb exoskeleton with two contact force/torque sensors, for a dual-arm device, which features a novel 3-degrees-offreedom exoskeleton shoulder design and a contact wrench mitigation controller, as demonstrated through simulation. With this work, we propose the essential technical steps towards a novel teleoperation system for elderly care.
Publication Date: 2013
European Physical Journal D (14346060)67(12)
A four-body approach based on the three-Coulomb distorted wave (3CDW) model is applied to study of the electron-impact single ionization of helium atoms. Triply differential cross sections (TDCS) are calculated for different values of the incident and ejection energies and various amounts of the scattering angles. The ejection angular distribution of the TDCS in general exhibits two peaks, binary and recoil peaks. The obtained results are compared with the available experimental data as well as other theoretical predictions. The comparison shows a good agreement between the present calculations and the measurements. Also, the obtained results are compatible with the other theories. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Publication Date: 2012
WOMENS HISTORY REVIEW (09612025)(2)pp. 233-252
The emergence of a genuine civil society with its democratic elements is of significant importance in furthering women's rights. This article explores the interrelation between democratization and the women's movement in Iran. In view of the fact that the pursuance of women's rights itself is part of the process of democratization, it is demonstrated that the fulfillment of women's rights cannot be postponed until the emergence of an ideal society, that is, an open society. This article also examines how the women's press, in the absence of a proper political party system, has become a key space wherein the debates about women's issues have been articulated.
Publication Date: 2021
Journal of Physics A: Mathematical and Theoretical (17518113)54(21)
In this paper, we first try to shed light on the ambiguities that exist in the literature in the generalization of the standard linear response theory (LRT) which has been basically formulated for closed systems to the theory of open quantum systems in the Heisenberg picture. Then, we investigate the linear response of a driven-dissipative optomechanical system (OMS) to a weak time-dependent perturbation using the so-called generalized LRT. It is shown how the Green's function equations of motion of a standard OMS as an open quantum system can be obtained from the quantum Langevin equations (QLEs) in the Heisenberg picture. The obtained results explain a wealth of phenomena, including the anti-resonance, normal mode splitting and the optomechanically induced transparency (OMIT). Furthermore, the reason why the Stokes or anti-Stokes sidebands are amplified or attenuated in the red or blue detuning regimes is clearly explainedwhich is in exact coincidence, especially in theweak-coupling regime, with the Raman-scattering picture. © 2021 Institute of Physics Publishing. All rights reserved.
Publication Date: 2023
IEEE Sensors Journal (1530437X)23(14)pp. 15570-15577
With strong evanescent waves, optical microfibers (MFs) provide guided lights the ability to directly interact with surrounding environments, whereby several fiber optics chemical sensors have been realized. In this study, based on MFs external refractive index (RI) sensitivity, a multimode optical fiber (MMF) specklegram RI sensor with MMF-MF-MMF configuration is presented. As the MF Section is exposed to the liquids of different RIs (in the range of 1.333-1.368), the interaction between the liquids and evanescent waves modulates the guidance status of the MF, thereby changes the excited modes within the end MMF Section and affects the output speckle pattern accordingly. The evaluation of the functionalities of the MFs with different waist diameters (11, 18, 33, and 42 μ m ) shows that the MF with 33- μ m waist diameter results in the highest output specklegram RI sensitivity, which has been quantified by the zero-mean normalized cross correlation coefficient (ZNCC). Moreover, the response time and sensitivity of the proposed fiber specklegram sensor (FSS) have been simultaneously improved by applying spacial filter on the captured speckles. The RI sensor has also been studied for the temperature detection and showed 0.013°C-1 linear sensitivity within the range of 25 °C-65 °C. Finally, the theoretical analysis of the supported modes by the MFs of the specified waist diameters verifies that 33- μ m sample with high number of guided modes and strong total evanescent waves is the optimum case for the MMF-MF-MMF specklegram RI sensor. © 2001-2012 IEEE.
Publication Date: 2021
Journal of Superconductivity and Novel Magnetism (15571947)34(10)pp. 2471-2477
Two single-phase iron and cobalt ferrite nanoparticles and a bi-magnetic soft/hard nanostructure of Fe3O4/CoFe2O4 were synthesized through the coprecipitation method at 80 °C. Also, a sample is made just by mixing the two single-phase ferrite nanoparticles. Assessment through XRD indicates that spinel structure was formed in all samples. The mean crystallite sizes of the single phase ferrites were estimated by applying Williamson–Hall method on the XRD patterns, which are 9 and 16 for iron and cobalt ferrite nanoparticles, respectively. The TEM results confirmed the formation of the spherical core/shell nanostructure with narrow size distribution (47 nm). The study of the different magnetic properties (HC, MS, TB, and TC) indicates that the magnetic behavior of the exchange coupled core/shell nanostructure was significantly different from that of the physically mixed sample. This difference is a fingerprint to distinguish an exchange coupled core/shell nanostructure from a physical mixture. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Publication Date: 2009
SOUTHEAST ASIAN BULLETIN OF MATHEMATICS (01292021)(2)pp. 207-208
In this short note, we prove that an element a of an infinite group is central if and only if aX boolean AND Xa not equal (empty set) for all infinite subsets X.
Publication Date: 2013
International Journal Of Engineering (10252495)(6)pp. 577-585
Adders and multipliers are two main parts of arithmetic units of computer hardware and play important role in reversible computations. This paper introduces a novel reversible 4x4 multiplier circuit that is based on an advanced Partial Product Generation Circuits (PPGC) with Peres gates only without duplicating gates. Again, an optimized Peres full adder reversible gate is used in Reversible Parallel Adder (RPA) part with accompaniment with the carry save adder technique. Comparison of the proposed design with previous ones shows that the proposed reversible multiplier improves the quantum parameters. The proposed design shows lower quantum cost and depth with the help of a novel design in PPGC. The circuit cost of the proposed design is a little higher than the best compared design, but the proposed design shows the lowest total cost which is defined as sum of quantum cost and circuit cost. Moreover, the number of gates, garbage input and output has no change regarding to the best compared design. The proposed multiplier can be generalized as an nxn bit multiplication.
Publication Date: 2016
Journal of Materials Science (15734803)51(22)pp. 9991-10004
In this study, a novel PAN/NaX/ZnO nanocomposite absorbent was introduced and its ability to remove of uranium anionic species, which are the most dominant species of uranium in water at natural pH, from contaminated waters was studied. In this regards, micro and nano sized NaX zeolite and PAN/NaX/ZnO nanocomposite were successfully synthesized and characterized using various methods, including X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FT-IR), atomic absorption spectroscopy (AAS), and Brunauer–Emmett–Teller (BET) specific surface area analysis. Batch technique was used to study the adsorption behavior of uranium ions from contaminated water as a function of solid–liquid ratio, initial uranium concentration, contact time, and temperature. Results showed that although NaX nanozeolite due to its negative framework charge, showed low sorption capacity for adsorption of uranium anionic species but the composite of it with ZnO nanoparticles and polyacrylonitrile (PAN) effectively improved its uranium adsorption capacity. The novel PAN/NaX/ZnO nanocomposite could selectively remove uranium ions from contaminated water with removal efficiency of more than 98.65 % in the presence of all anions and cations which are available in waters. © 2016, Springer Science+Business Media New York.
Publication Date: 2017
INTERNATIONAL JOURNAL OF COMPUTER SCIENCE AND NETWORK SECURITY (17387906)(7)pp. 301-305
Monitoring vital body sign is very important in medical science and is one of the basic requirements in this branch of science. This has been done manually in the past. With technology improvement in monitoring systems, automated system is used without human intervention. In these systems, sensors connect to patient's body and received data through sensors would be transmitted through wires connected to the central data system for displaying in its monitor. In this paper, we introduce implementing a media access protocol namely PO-MAC. In this protocol collected data through sensors would be transmitted to data center node (data center service node). For proposed implemented protocol evaluation obtained power transmission values, power consumption and delay rate is compared with 2 well known protocols in this area (scope).
Publication Date: 2006
Physica B: Condensed Matter (09214526)371(2)pp. 309-312
The solid-state reduction of Bi2O3 to bismuth (Bi) nanoparticles by high-energy ball milling of raw materials (Bi2O 3 and Fe) in air and argon atmospheres has been described. XRD results show that in addition to bismuth, a second phase of nanocrystalline magnetite is also formed. This is due to the formation of Fe2O 3 and the subsequent change to Fe3O4 in the course of ball milling. Mean particle sizes of the obtained Bi and Fe 3O4 particles were 22 and 18 nm, respectively, using Scherrer's formula. A saturation magnetization of 80 emu/g is achieved for magnetic phase (Fe3O4). As both Bi and magnetite were nanosized particles, it was not possible to separate these two phases by the magnetic separation technique. A novel technique based on different thermal expansions of the Bi and Fe3O4 was then used to extract metallic Bi from the as-milled powders. © 2005 Elsevier B.V. All rights reserved.
As robots become more and more intelligent, the complexity of the algorithms behind them is increasing. Since these algorithms require high computation power from the onboard robot controller, the weight of the robot and energy consumption increases. A promising solution to tackle this issue is to relocate the expensive computation to the cloud. In this pioneering work, the possibility of relocating a state-of-the-art nonlinear control is investigated. To this end, the Unified Force-Impedance Controller (UFIC) is relocated to a remote location and high frequency feedback loop is established by including the remote controller in the loop. Passivity analysis is used to ensure the stability of the whole system, comprising the robot in interaction with the environment, the communication channel, as well as the remote controller. The instability associated with the communication channel is resolved by Time Domain Passivity Approach (TDPA). The performance of the proposed framework is experimentally evaluated on a robot arm in interaction with the environment. The results illustrate the stability of the system to a time-varying delay of up to 50 +/- 10ms.
Publication Date: 2010
Annals of Physics (1096035X)325(9)pp. 1976-1986
A canonical quantization scheme is represented for a quantum system interacting with a non-linear absorbing environment. The environment is taken anisotropic and the main system is coupled to its environment through some coupling tensors of various ranks. The non-linear response equation of the environment against the motion of the main system is obtained. The non-linear Langevin-Schrödinger equation is concluded as the macroscopic equation of motion of the dissipative system. The effect of non-linearity of the environment is investigated on the spontaneous emission of an initially excited two-level atom imbedded in such an environment. © 2010 Elsevier Inc.
Publication Date: 2015
New Journal Of Physics (13672630)17(12)
Motivated by the problem of many-body localization and the recent numerical results for the level and eigenfunction statistics on the random regular graphs, a generalization of the Rosenzweig-Porter random matrix model is suggested that possesses two transitions. One of them is the Anderson localization transition from the localized to the extended states. The other one is the ergodic transition from the extended non-ergodic (multifractal) states to the extended ergodic states.Weconfirm the existence of both transitions by computing the two-level spectral correlation function, the spectrum of multifractality f (α) and thewave function overlapwhich consistently demonstrate these two transitions.
