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Sample records for bare cylindrical reactor

  1. Non probabilistic solution of uncertain neutron diffusion equation for imprecisely defined homogeneous bare reactor

    International Nuclear Information System (INIS)

    Highlights: • Uncertain neutron diffusion equation of bare square homogeneous reactor is studied. • Proposed interval arithmetic is extended for fuzzy numbers. • The developed fuzzy arithmetic is used to handle uncertain parameters. • Governing differential equation is modelled by modified fuzzy finite element method. • Fuzzy critical eigenvalues and effective multiplication factors are investigated. - Abstract: The scattering of neutron collision inside a reactor depends upon geometry of the reactor, diffusion coefficient and absorption coefficient etc. In general these parameters are not crisp and hence we get uncertain neutron diffusion equation. In this paper we have investigated the above equation for a bare square homogeneous reactor. Here the uncertain governing differential equation is modelled by a modified fuzzy finite element method. Using modified fuzzy finite element method, obtained eigenvalues and effective multiplication factors are studied. Corresponding results are compared with the classical finite element method in special cases and various uncertain results have been discussed

  2. Experimental study of fluidic mixing in a cylindrical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Orfaniotis, A.; Fonade, C.; Lalane, M.; Doubrovine, N. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)

    1996-04-01

    Fluidic mixing in a cylindrical reactor was studied in an effort to determine the effect of jet disposition and the viscosity of the liquid. The tests were carried out in a a tank using conductimetric probes to measure the mixing time. Results indicated that relative jet positions leading to an impinging flow structure were less efficient than shear flow configurations. When these results were compared with results of earlier work by Simon and Fonade (1993) it was found that they were consistent with the exponent 2/3 obtained by them in experiments with turbulent jets. It was pointed out that these mixing times apply only to mixing in cylindrical reactors. With different geometries, such as basins and lagoons with small liquid depths, a new choice of the reference length included in the expression of the reference time will be needed. 10 refs., 3 tabs., 16 figs.

  3. MODIF-a code for completely reflected cylindrical reactors

    International Nuclear Information System (INIS)

    MODIF-Code is a computer program for calculating the reflector saving, material buckling, and effective multiplication constant of completely reflected cylindrical reactors. The calculational method is based on a modified iterative algorithm which has been deduced from the general analytical solution of the two group diffusion equations. The code has been written in FORTRAN language suited for the ICL-1906 computer facility at Cairo University. The computer time required to solve a problem of actual reactor is less than 1 minute. The problem converges within five iteration steps. The accuracy in determining the effective multiplication constant lies within +-10-5. The code has been applied to the case of UA-RR-1 reactor, the results confirm the validity and accuracy of the calculational method

  4. Numerical solution of uncertain neutron diffusion equation for imprecisely defined homogeneous triangular bare reactor

    Indian Academy of Sciences (India)

    S Nayak; S Chakraverty

    2015-10-01

    In this paper, neutron diffusion equation of a triangular homogeneous bare reactor with uncertain parameters has been investigated. Here the involved parameters viz. geometry of the reactor, diffusion coefficient and absorption coefficient, etc. are uncertain and these are considered as fuzzy. Fuzzy values are handled through limit method which was defined for interval computations. The concept of fuzziness is hybridised with traditional finite element method to propose fuzzy finite element method. The proposed fuzzy finite element method has been used to obtain the uncertain eigenvalues of the said problem. Further these uncertain eigenvalues are compared with the traditional finite element method in special cases.

  5. A high temperature reactor accommodated in a cylindrical pressure vessel

    International Nuclear Information System (INIS)

    This concerns the mixing of hot gases of a high temperature reactor with spherical fuel elements which is placed in a cylindrical pressure vessel. The cooling gas is blown in from above and after passing through the pebble bed it is collected on the bottom where the graphite blocks form a kind of pillard hall. According to this invention, in front of each channel through which the hot gas is blown off there is placed a specially formed replacement body for deviation purpose, and thus the hot gases are thoroughly mixed. Like this the gas flow gets to the components of the primary coolant circuit with a regular temperature. (GL)

  6. The reactivity of a central air gap in a bare reactor

    International Nuclear Information System (INIS)

    The reactivity of a central air gap in a bare reactor. Two methods axe presented for calculation of the reactivity equivalence of a central gap in a bare reactor with rectangular cross-section. The first is a perturbation theory and has been developed by Friedman in an unpublished paper. The second method is an application of variation calculus. In both cases the eigenvalue is solved for the transport equation in integral form. The principal difference between the two methods is in the assumption for the flux shape. In the perturbation theory, it is assumed that the flux is unperturbed and has the form A cos π x/L. The reactivity as a function of the gap width is expressed in closed form in one and two energy groups, but the expression is valid only for reactivity changes less than about 8%. The variation calculus is developed only for one energy group, but the accuracy is approximately independent of the gap width. This is obtained by varying the expression for the flux in order to optimize the functional integral. The results are compared with those obtained by Chernick and Kaplan by diffusion theoretical methods. (author)

  7. Conduction heat transfer in a cylindrical dielectric barrier discharge reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sadat, H. [Laboratoire d' Etudes Thermiques, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France)], E-mail: hamou.sadat@univ-poitiers.fr; Dubus, N. [Laboratoire d' Etudes Thermiques, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France); Pinard, L.; Tatibouet, J.M.; Barrault, J. [Laboratoire en catalyse et chimie organique, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France)

    2009-04-15

    The thermal behaviour of a dielectric barrier discharge reactor is studied. The experimental tests are performed on a laboratory reactor with two working fluids: helium and air. A simple heat conduction model for calculating the heat loss is developed. By using temperature measurements in the internal and external electrodes, a thermal resistance of the reactor is defined. Finally, the percentage of the input power that is dissipated to the environment is given.

  8. Neutronic characterization of cylindrical core of minor excess reactivity in the nuclear reactor IPEN/MB-01 from the measure of neutron flux distribution and its reactivity ratio

    International Nuclear Information System (INIS)

    When compared to a rectangular parallelepiped configuration the cylindrical configuration of a nuclear reactor core has a better neutron economy because in this configuration the probability of the neutron leakage is smaller, causing an increase in overall reactivity in the system to the same amount of fuel used. In this work we obtained a critical cylindrical configuration with the control rods 89.50% withdraw from the active region of the IPEN/MB-01 core. This is the cylindrical configuration minimum possible excess of reactivity. Thus we obtained a cylindrical configuration with a diameter of only 28 fuel rods with lowest possible excess of reactivity. For this purpose, 112 peripheral fuel rods are removed from standard reactor core (rectangular parallelepiped of 28x28 fuel rods). In this configuration the excesses of reactivity is approximated 279 pcm. From there, we characterize the neutron field by measuring the spatial distribution of the thermal and epithermal neutron flux for the reactor operating power of 83 watts measured by neutron noise analysis technique and 92.08± 0.07 watts measured by activation technique [10]. The values of thermal and epithermal neutron flux in different directions, axial, radial north-south and radial east-west, are obtained in the asymptotic region of the reactor core, away from the disturbances caused by the reflector and control bar, by irradiating thin gold foils infinitely diluted (1% Au - 99% Al) with and without (bare) cadmium cover. In addition to the distribution of neutron flux, the moderator temperature coefficient, the void coefficient, calibration of the control rods were measured. (author)

  9. Optimal design study of cylindrical finned reactor for solar adsorption cooling machine

    Energy Technology Data Exchange (ETDEWEB)

    Allouache, N. [Univ. des Sciences et de la Technologie Houari Boumediene, Bab Ezzouar (Algeria). Faculte de Genie Mecanique et de Genie des Procedes; Al Mers, A. [Moulay Ismail Univ., Meknes (Morocco). Ecole National Superieure d' Art et Metiers

    2010-07-01

    Solid adsorption cooling machines use medium temperature industrial waste heat together with a renewable energy source, such as solar energy. The adsorption cooling machine consists of an evaporator, a condenser and a reactor containing a solid adsorbent. In this study, a model was developed for thermodynamic performance analysis and optimization of a cylindrical finned solar reactor in an adsorption refrigerator working with activated carbon-ammonia. The heat and mass transfer in the adsorption cooling machine was determined. The model was validated using experimental results. The study investigated the sensitivity of the machine performance versus the geometrical configuration of the reactor. The study showed that for an optimized reactor, a higher fin number significantly reduces the heat losses of the reactor. It was concluded that the solar coefficient of performance (COP) of an optimized reactor can reach 45 per cent when the number of fins varies between 5 and 6. 10 refs., 4 figs.

  10. Rapid Regeneration of Chelated Iron Desulfurization Solution Using Electrochemical Reactor with Rotating Cylindrical Electrodes

    Institute of Scientific and Technical Information of China (English)

    于永; 刘有智; 祁贵生

    2014-01-01

    A new electrochemical reactor with rotating cylindrical electrodes was designed and used to increase the regeneration efficiency of chelated iron desulfurization solution. The influence of operating parameters, such as the rotation speed of electrode, voltage, and inlet air and liquid flow rates, on the regeneration rate was investigated. Compared with the traditional tank-type reactor, the regeneration rate with the new electrochemical reactor was in-creased significantly. Under the optimum conditions, the regeneration rate was increased from 45.3% to 84.8%. Experimental results of continuous operation indicated that the new electrochemical regeneration method had some merits including higher regeneration efficiency, smaller equipment size and good stability in operation.

  11. Natural and mixed convection in the cylindrical pool of TRIGA reactor

    Science.gov (United States)

    Henry, R.; Tiselj, I.; Matkovič, M.

    2016-05-01

    Temperature fields within the pool of the JSI TRIGA MARK II nuclear research reactor were measured to collect data for validation of the thermal hydraulics computational model of the reactor tank. In this context temperature of the coolant was measured simultaneously at sixty different positions within the pool during steady state operation and two transients. The obtained data revealed local peculiarities of the cooling water dynamics inside the pool and were used to estimate the coolant bulk velocity above the reactor core. Mixed natural and forced convection in the pool were simulated with a Computational Fluid Dynamics code. A relatively simple CFD model based on Unsteady RANS turbulence model was found to be sufficient for accurate prediction of the temperature fields in the pool during the reactor operation. Our results show that the simple geometry of the TRIGA pool reactor makes it a suitable candidate for a simple natural circulation benchmark in cylindrical geometry.

  12. Modified divergence theorem for analysis and optimization of wall reflecting cylindrical UV reactor

    Directory of Open Access Journals (Sweden)

    Milanović Đurđe R.

    2011-01-01

    Full Text Available In this paper, Modified Divergence Theorem (MDT, known in earlier literature as Gauss-Ostrogradsky theorem, was formulated and proposed as a general approach to electromagnetic (EM radiation, especially ultraviolet (UV radiation reactor modeling. Formulated mathematical model, based on MDT, for multilamp UV reactor was applied to all sources in a reactor in order to obtain intensity profiles at chosen surfaces inside reactor. Applied modification of MDT means that intensity at a real opaque or transparent surface or through a virtual surface, opened or closed, from different sides of the surface are added and not subtracted as in some other areas of physics. Derived model is applied to an example of the multiple UV sources reactor, where sources are arranged inside a cylindrical reactor at the coaxial virtual cylinder, having the radius smaller than the radius of the reactor. In this work, optimization of a reactor means maximum transfer of EM energy sources into the fluid for given fluid absorbance and fluid flow-dose product. Obtained results, for in advanced known water quality, gives unique solution for an optimized model of a multilamp reactor geometry. As everyone can easily verify, MDT is very good starting point for every reactor modeling and analysis.

  13. Contribution to analytical theory of neutron resonance absorption in heterogeneous reactor systems with cylindrical geometry

    International Nuclear Information System (INIS)

    Following a review of the existing theories od resonance absorption this thesis includes a new approach for calculating the effective resonance integral of absorbed neutrons, new approximate formula for the penetration factor, an analysis of the effective resonance integral and the correction of the resonance integral taking into account the interference of potential and resonance dissipation. A separate chapter is devoted to calculation of the effective resonance integral for the regular reactor lattice with cylindrical fuel elements

  14. Operating regimes of corona and silent discharges in coaxial cylindrical reactors

    International Nuclear Information System (INIS)

    The physical mechanisms of the electrical discharges formed in coaxial cylindrical reactors have been investigated in this paper under different operating conditions for the reactors. The reactors were fed by natural air flowing with a constant rate at atmospheric conditions and stressed by an ac voltage. The wave form of the ac voltage applied to the reactors has been studied corresponding to the discharge current, over the whole range of the operating conditions. The results have shown that the operating conditions for the reactor modify the physical mechanism inside it in the form of either corona or silent discharges or spark over. The onset voltage of the different electrical discharges formed inside the reactors has agreed with Peek's equation, whatever the operating conditions. Subsequently, empirical equations concerning the operating conditions for the reactors have been derived by using Peek's and Townsend's equations. The derived equations represent suitable criterions to predict the different types of the electrical discharges that will form inside the reactors under any operating conditions. The results have been illustrated by recorded oscillograms showing the wave form of the ac voltage applied to the reactors and the corresponding current pulses

  15. Inspection of the Grand Gulf Nuclear Station reactor coolant pump shaft using the cylindrically guided wave technique

    International Nuclear Information System (INIS)

    This paper describes the inspection of the Grand Gulf Nuclear Station reactor coolant pump shaft using the cylindrically guided wave technique. The topics of the paper include a description of the pump shaft problem, metallurgical testing results, nondestructive examination (NDE) requirements, NDE work conducted, conventional inspection technology, cylindrically guided wave technique (CGWT), and the results of CGWT inspection on boiling water reactor pump shaft. The paper consists of overheads from the presentation

  16. Uniform coating of TiO2 thin films on particles by rotating cylindrical PCVD reactor.

    Science.gov (United States)

    Kim, Dong-Joo; Baeg, Jin-Ook; Moon, Sang-Jin; Kim, Kyo-Seon

    2009-07-01

    We analyzed TiO2 thin film growth on glass particles in a rotating cylindrical plasma chemical vapor deposition (PCVD) reactor and numerically investigated the effects of several process variables on the film growth. An increase in titanium tetra-isopropoxide (TTIP) or O2 partial pressure can enhance the film growth rate on the particles because the concentration of TiO(x), which is the main precursor for thin film growth, becomes higher in the reactor. As the particle diameter decreases, the TiO(x) concentration increases and the thin film on the particles grows more quickly. The neutral-radical reaction between TTIP and O radicals for TiO(x) generation in TTIP + O2 plasmas can be important to enhance the thin film growth rate on the particles. The growth rate of TiO2 film predicted in this study was 1 approximately 20 nm/min, which is in good agreement with the published experimental results. This study suggests that a uniform TiO2 thin film on particles can be obtained by using a rotating cylindrical PCVD reactor. PMID:19916444

  17. Multigroup program for calculating the thermal neutron utilization factor in multizone cylindrical reactor cell (MGPRAKTINETs)

    International Nuclear Information System (INIS)

    The MGPRAKTINETs computer code for the BESM-6 computer intended for calculation of zone average trmal neutron group fluxes and functionals is described. The neutron spatial-energy distribution in a multizone cyllindrically-symmetric reactor cell is calculated by the operator splitting method. For the solution of the spatial part of the problem the method of surface pseudosources (Gsub(N)-approximation) in approximation of plane derivatives from the energy neutron current is employed. The energy part of the problem is solved in a multigroup approximation. Computer code efficiency has been demonstrated by calculation of two-zone cells with internal and external sources of the cell with on additional absorber and RBMK cell with reduction of the latter to cylindrical geometry. It is shown that the approximation of plane derivatives of neutron energy current allows calculating reactor cell characteristics with a sufficient for design calculations accuracy

  18. A Cylindrical Shielding Design Concept for the Prototype Gen-IV Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    In the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR), a metal fueled, blanket-free, pool type SFR concept is adopted to acquire the inherent safety characteristics and high proliferation-resistance. In the pool type fast reactor, the intermediate heat exchangers (IHXs), which transfer heat from the primary sodium pool to a secondary sodium loop, are placed inside of the reactor vessel. Hence, secondary sodium passing the IHXs can be radioactivated by a 23Na(n,g)24Na reaction, and radioactivated secondary sodium causes a significant dose in the Steam Generator Building (SGB). Therefore, a typical core of a pool type fast reactor is usually surrounded by a massive quantity of shields. In addition, the blanket composed of depleted uranium plays a role as superior shielding material; a significant increase in shields is required in the blanket-free pool type SFR. In this paper, a new cylindrical shielding design concept is proposed for a blanket-free pool type SFR. In a conventional shielding design, massive axial shields are required to prevent irradiation of secondary sodium passing IHXs and they should be replaced according to the subassembly replacement in spite of negligible depletion of the shielding material. The proposed shielding design concept minimizes the quantity of shields without their replacement. In this paper, a new cylindrical shielding design concept is proposed for a blanket-free pool type SFR such as a PGSFR. The proposed design concept satisfied the dose limit in the steam generator building successfully without introducing a large quantity of B4C shielding inside the subassembly

  19. Optimal design study of cylindrical finned reactor for solar adsorption cooling machine working with activated carbon-ammonia pair

    International Nuclear Information System (INIS)

    This paper presents a model describing the heat and mass transfer in cylindrical finned reactor of solar adsorption refrigerator. Giving the meteorological data as boundary conditions on the reactor; the model computes the solar coefficient of performance (COPs). The validity of the model has been tested by using experimental results. An analysis of the sensitivity of the COPs versus the geometrical parameters of the reactor (radius of the reactor, fins thickness and fins number) is mad. Then the model is applied to optimize the solar reactor. The COPs is used as an optimization criterion. The geometrical parameters where the COPs of the machine reach a maximum have been calculated

  20. On the Effectiveness of Wastewater Cylindrical Reactors: an Analysis Through Steiner Symmetrization

    Science.gov (United States)

    Díaz, J. I.; Gómez-Castro, D.

    2016-03-01

    The mathematical analysis of the shape of chemical reactors is studied in this paper through the research of the optimization of its effectiveness η such as introduced by R. Aris around 1960. Although our main motivation is the consideration of reactors specially designed for the treatment of wastewaters our results are relevant also in more general frameworks. We simplify the modeling by assuming a single chemical reaction with a monotone kinetics leading to a parabolic equation with a non-necessarily differentiable function. In fact we consider here the case of a single, non-reversible catalysis reaction of chemical order q, 0kinetics is given by β (w)=λ wq for some λ >0). We assume the chemical reactor of cylindrical shape Ω =G× (0,H) with G and open regular set of {R}2 not necessarily symmetric. We show that among all the sections G with prescribed area the ball is the set of lowest effectiveness η (t,G). The proof uses the notions of Steiner rearrangement. Finally, we show that if the height H is small enough then the effectiveness can be made as close to 1 as desired.

  1. Buckling measurement in the IPEN/MB-01 nuclear reactor in cylindrical configuration of minor excess of reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Purgato, Rafael Turrini; Bitelli, Ulysses d' Utra; Aredes, Vitor Ottoni; Silva, Alexandre F. Povoa da; Santos, Diogo Feliciano dos; Lima, Ana Cecilia de Souza, E-mail: ubitelli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    This work presents the results of experimental Buckling in the IPEN/MB-01 nuclear reactor in its cylindrical configuration with 28 fuel rods along its diameter. The IPEN/MB-01 is a zero power reactor designed to operate at a maximum power of 100 watts. It is a versatile nuclear facility, which allows for the simulation of all the characteristics of a nuclear power reactor making it an ideal test bed for this kind of measurement. A mapping of neutron flux inside the reactor is carried out in order to determine the total Buckling of the cylindrical configuration. The reactor was operated for one hour. Then, the activity of the fuel rods is measured by gamma ray spectrometry using a HPGe solid state detector and a suitable rod scanner. Photon energies of 276.6keV from {sup 239}Np (neutron capture (n,?) nuclear reaction) and 293.3keV from {sup 143}Ce (fission (n,f) nuclear reaction on both {sup 238}U and {sup 235}U) , are respectively along both axial and radial directions. Other measurements are performed using gold wires and foils along radial and axial directions of the reactor core. The three methods above resulted in a weighted average value of 93.18 ± 8.47 m-2 for the Total Buckling of this cylindrical core configuration with 28 control rods along its diameter with 568 fuel rods and only 271 pcm of excess reactivity. (author)

  2. Improved collision probability method for thermal-neutron-flux calculation in a cylindrical reactor cell

    International Nuclear Information System (INIS)

    An improved collision probability method for thermal-neutron-flux calculation in a cylindrical reactor cell has been developed. Expanding the neutron flux and source into a series of even powers of the radius, one' gets a convenient method for integration of the one-energy group integral transport equation. It is shown that it is possible to perform an analytical integration in the x-y plane in one variable and to use the effective Gaussian integration over another one. Choosing a convenient distribution of space points in fuel and moderator the transport matrix calculation and cell reaction rate integration were condensed. On the basis of the proposed method, the computer program DISKRET for the ZUSE-Z 23 K computer has been written. The suitability of the proposed method for the calculation of the thermal-neutron-flux distribution in a reactor cell can be seen from the test results obtained. Compared with the other collision probability methods, the proposed treatment excels with a mathematical simplicity and a faster convergence. (author)

  3. Determination of buckling and probability of leakage of neutron in the IPEN/MB-01 reactor in cylindrical configuration

    International Nuclear Information System (INIS)

    One of the key parameters in reactor physics is the Buckling of a reactor core. It is related to important parameters such as reaction rates, nuclear power operation, fuel burning, among others. In a critical reactor, the Buckling depends on the geometric and material characteristics of the reactor core. This work presents the results of experimental Buckling in the reactor IPEN/MB-01 nuclear reactor in its cylindrical configuration with 28 fuel rods along its diameter. The IPEN/MB-01 is a zero power reactor designed to operate at a maximum power of 100 watts, it is a versatile nuclear facility which allows the simulation of all the characteristics of a large nuclear power reactor and ideal for this type of measurement. We conducted a mapping of neutron flux inside the reactor and thereby determined the total Buckling of the cylindrical configuration. The reactor was operated for one hour. Then, the activity of the fuel rods was measured by gamma spectrometry on a rod scanner HPGe detector. We analyzed the gamma photons of the 239Np (276,6 keV) for neutron capture (n,γ) and the 143Ce (293,3 keV) for fission (n,f) on both 238U and 235U, respectively. We analyzed the axial and radial directions. Other measurements were performed using wires and gold foils in the radial and axial directions of the reactor core. The Buckling Total obtained from the three methods by weighted mean is 96,55 ± 7,47 m-2. The goal is to obtain experimental values of a set of experimental data to allow one direct comparison with values calculated by the codes used in reactor physics CITATION and MCNP. (author)

  4. Electrochemical treatment of Procion Black 5B using cylindrical flow reactor-A pilot plant study

    International Nuclear Information System (INIS)

    The paper presents the results of an efficient electrochemical treatment of Procion Black 5B-a pilot plant study. Experiments were conducted at different current densities and selected electrolyte medium using Ti/RuO2 as anode, stainless-steel as cathode in a cylindrical flow reactor. By cyclic voltammetric analysis, the best condition for maximum redox reaction rate was found to be in NaCl medium. During the various stages of electrolysis, parameters such as COD, colour, FTIR, UV-vis spectra studies, energy consumption and mass transfer coefficient were computed and presented. The experimental results showed that the electrochemical oxidation process could effectively remove colour and the chemical oxygen demand (COD) from the synthetic dye effluent. The maximum COD reduction and colour removal efficiencies were 74.05% and 100%, respectively. Probable theory, reaction mechanism and modeling were proposed for the oxidation of dye effluent. The results obtained reveal the feasibilities of application of electrochemical treatment for the degradation of Procion Black 5B

  5. Plasma properties in a large-volume, cylindrical and asymmetric radio-frequency capacitively coupled industrial-prototype reactor

    Science.gov (United States)

    Lazović, Saša; Puač, Nevena; Spasić, Kosta; Malović, Gordana; Cvelbar, Uroš; Mozetič, Miran; Radetić, Maja; Petrović, Zoran Lj

    2013-02-01

    We have developed a large-volume low-pressure cylindrical plasma reactor with a size that matches industrial reactors for treatment of textiles. It was shown that it efficiently produces plasmas with only a small increase in power as compared with a similar reactor with 50 times smaller volume. Plasma generated at 13.56 MHz was stable from transition to streamers and capable of long-term continuous operation. An industrial-scale asymmetric cylindrical reactor of simple design and construction enabled good control over a wide range of active plasma species and ion concentrations. Detailed characterization of the discharge was performed using derivative, Langmuir and catalytic probes which enabled determination of the optimal sets of plasma parameters necessary for successful industry implementation and process control. Since neutral atomic oxygen plays a major role in many of the material processing applications, its spatial profile was measured using nickel catalytic probe over a wide range of plasma parameters. The spatial profiles show diffusion profiles with particle production close to the powered electrode and significant wall losses due to surface recombination. Oxygen atom densities range from 1019 m-3 near the powered electrode to 1017 m-3 near the wall. The concentrations of ions at the same time are changing from 1016 to the 1015 m-3 at the grounded chamber wall.

  6. Neutronic characterization of cylindrical core of minor excess reactivity in the nuclear reactor IPEN/MB-01 from the measure of spatial and energetic distribution of neutron flux distribution

    International Nuclear Information System (INIS)

    In this work was conducted the mapping of the thermal and epithermal neutrons flux and the energy spectrum of the neutrons in the reactor core IPEN/MB-01 for a cylindrical core configuration with minor excess reactivity, which is 28 x 28 fuel rods arranged in north-south and east-west directions. The calibration of control rods for this configuration determined their excess reactivity. The lower excess reactivity in the core decreased neutron flux disturbance caused by the neutron absorbing rods , given that the nuclear reactor was operated with the rods almost completely removed . Was used the 'Activation Analysis Technique' with the thin foil activation detectors ( infinitely diluted and hyper-pure), of different materials that work in different energy ranges, to calculate the saturation activity, used for determining the neutron flux and in the SANDBP code as input for the calculation of the neutrons energy spectrum. To discriminate thermal and epithermal flux , was used the 'Cadmium RatioTechnique' . The activation detectors were distributed in a total of 140 radial and axial positions in the reactor core and 16 irradiation, with bare and covered with cadmium activation foils. A model of this configuration was simulated by MCNP-5 code to determine the cadmium correction factor and comparison of the results obtained experimentally. The cylindrical configuration desired, with 17% less fuel than the standard rectangular configuration (28 x 26 fuel rods), reached criticality with the control rods approximately 90% removed, which decreased considerably the disturbance in neutron flux. Given the highest power density of the 28 x 28 cylindrical core, the neutron flux increased by over 50% in the central regions of the core compared to the values of the 28 x 26 standard rectangular core. (author)

  7. A planar circular detector based on multiple point chemi- or bio-luminescent source within a coaxial cylindrical reactor

    International Nuclear Information System (INIS)

    An analytical method was proposed for calculating radiative fluxes incident on a planar circular detector from a volume multiple point chemi- or bio-luminescent source inside a coaxial cylindrical reactor. The method was designed for a cylindrical reactor when the surface reflections were neglected and when chemi- or bio-luminescence reaches a detector embedded in the same homogeneous optical medium as the point emitters of the volume multiple point source model. The radiative fluxes from arbitrarily distributed point emitters were expressed by one generalized quadruple-integral formula. Then some double- and single-integral formulas were obtained for calculating radiative fluxes from identically radiating point emitters uniformly distributed within the reactor. Selected results were computed and illustrated graphically. The obtained formulas are suitable for optimizing and/or calibrating the considered source-detectors systems (optical radiometers or luminometers) and determining radiative fluxes generated by chemical, biological, and physical processes leading to chemi-, bio-, radio-, and sono-luminescence for example.

  8. Simultaneous Organics and Nutrients Removal from Domestic Wastewater in a Combined Cylindrical Anoxic/Aerobic Moving Bed Biofilm Reactor

    OpenAIRE

    Husham T. Ibrahim; He Qiang; Wisaam S. Al-Rekabi

    2014-01-01

    The aim of present study was to design and construct an continuous up-flow pilot scale Moving Bed Biofilm Reactor (MBBR) which is consists of combined cylindrical Anoxic/Aerobic MBBR in nested form with anoxic/aerobic volume ratio equal to 0.16 to treated 4 m3 /days of domestic wastewater in Chongqing city at Southwest China. The treatment must be satisfactory to meet with grade B of discharge standard of pollutants for municipal wastewater treatment plant in China (GB/T18918-2002). Kaldnes (...

  9. One group neutron flux at a point in a cylindrical reactor cell calculated by Monte Carlo

    International Nuclear Information System (INIS)

    Mean values of the neutron flux over material regions and the neutron flux at space points in a cylindrical annular cell (one group model) have been calculated by Monte Carlo. The results are compared with those obtained by an improved collision probability method (author)

  10. Investigations of flow and temperature field development in bare and wire-wrapped reactor fuel pin bundles cooled by sodium

    International Nuclear Information System (INIS)

    Highlights: ► We study sodium flow and temperature development in fuel pin bundles. ► Pin diameter, number of pins, wire wrap and ligament gap are varied as parameters. ► Flow development is achieved within ∼30–40 hydraulic diameters. ► Thermal development is attained only for small pin diameter and less number of pins. ► Wire wrap and ligament gap strongly influence Nusselt number. - Abstract: Simultaneous development of liquid sodium flow and temperature fields in the heat generating pin bundles of reactor has been investigated. Development characteristics are seen to be strongly influenced by pin diameter, number of pins, helical wire-wrap, ligament gap between the last row of pins and hexcan wall and Reynolds number. Flow development is achieved within an axial length of ∼125 hydraulic diameters, for all the pin bundle configurations considered. But temperature development is attained only if the pin diameter is small or the number of pins is less. In the case of large pin diameter with more pins, temperature development could not be achieved even after a length of ∼1000 hydraulic diameters. The reason for this behavior is traced to be the weak communication among sub-channels in tightly packed bundles. It is seen that the pin Nusselt number decreases from center to periphery in a bundle. Also, if the ligament gap is narrow, the Nusselt number is large and more uniform. Flow development length is short if the Reynolds number is large and the converse is true for thermal development length. Helical wire-wrap shortens the thermal entry length and significantly enhances the global Nusselt number. But, its influence on hydrodynamic entry length is not significant

  11. Simultaneous Organics and Nutrients Removal from Domestic Wastewater in a Combined Cylindrical Anoxic/Aerobic Moving Bed Biofilm Reactor

    Directory of Open Access Journals (Sweden)

    Husham T. Ibrahim

    2014-03-01

    Full Text Available The aim of present study was to design and construct an continuous up-flow pilot scale Moving Bed Biofilm Reactor (MBBR which is consists of combined cylindrical Anoxic/Aerobic MBBR in nested form with anoxic/aerobic volume ratio equal to 0.16 to treated 4 m3 /days of domestic wastewater in Chongqing city at Southwest China. The treatment must be satisfactory to meet with grade B of discharge standard of pollutants for municipal wastewater treatment plant in China (GB/T18918-2002. Kaldnes (K1 media was used as a carrier in both reactors at a media fill ratio equal to 50%. The reactors was operated under the Anoxic/Oxic (An/O process which must meet stringent TN limits without sludge returning into the system and only an internal recycling was performed from aerobic to anoxic reactor. After developing the biofilm on the media, reactor was operated at 3 different Hydraulic Residence Time (HRT ranging from 4.95 to 8.25 h. During operation the internal recycle ratio to eliminate nitrogen compounds were 100% of inflow rate and the average Dissolved Oxygen concentration (DO in aerobic and anoxic MBBRs were 4.49 and 0.16 mg/L, respectively. The obtained results showed that the HRT of 6.2 h was suitable for simultaneous removal of COD, NH4+-N, TN and TP. In this HRT the average removal efficiencies were 93.15, 98.06, 71.67 and 90.88% for COD, NH4+-N, TN and TP, respectively.

  12. Spatial Abundance and Distribution of Potential Microbes and Functional Genes Associated with Anaerobic Mineralization of Pentachlorophenol in a Cylindrical Reactor

    Science.gov (United States)

    Li, Zhi-Ling; Nan, Jun; Huang, Cong; Liang, Bin; Liu, Wen-Zong; Cheng, Hao-Yi; Zhang, Chunfang; Zhang, Dongdong; Kong, Deyong; Kanamaru, Kyoko; Kobayashi, Tetsuo; Wang, Ai-Jie; Katayama, Arata

    2016-01-01

    Functional interplays of microbial activity, genetic diversity and contaminant transformation are poorly understood in reactors for mineralizing halogenated aromatics anaerobically. Here, we investigated abundance and distribution of potential microbes and functional genes associated with pentachlorophenol (PCP) anaerobic mineralization in a continuous-flow cylindrical reactor (15 cm in length). PCP dechlorination and the metabolite (phenol) were observed at segments 0-8 cm from inlet, where key microbes, including potential reductive dechlorinators (Dehalobacter, Sulfurospirillum, Desulfitobacterium and Desulfovibrio spp.) and phenol degraders (Cryptanaerobacter and Syntrophus spp.), as well as putative functional genes, including putative chlorophenol reductive dehalogenase (cprA) and benzoyl-CoA reductase (bamB), were highly enriched simultaneously. Five types of putative cprAs, three types of putative bamBs and seven types of putative nitrogenase reductase (nifHs) were determined, with their copy numbers decreased gradually from inlet to outlet. Distribution of chemicals, bacteria and putative genes confirmed PCP dechlorination and phenol degradation accomplished in segments 0-5 cm and 0-8 cm, respectively, contributing to a high PCP mineralization rate of 3.86 μM d-1. Through long-term incubation, dechlorination, phenol degradation and nitrogen fixation bacteria coexisted and functioned simultaneously near inlet (0-8 cm), verified the feasibility of anaerobic mineralization of halogenated aromatics in the compact reactor containing multiple functional microbes.

  13. Spatial Abundance and Distribution of Potential Microbes and Functional Genes Associated with Anaerobic Mineralization of Pentachlorophenol in a Cylindrical Reactor

    Science.gov (United States)

    Li, Zhi-Ling; Nan, Jun; Huang, Cong; Liang, Bin; Liu, Wen-Zong; Cheng, Hao-Yi; Zhang, Chunfang; Zhang, Dongdong; Kong, Deyong; Kanamaru, Kyoko; Kobayashi, Tetsuo; Wang, Ai-Jie; Katayama, Arata

    2016-01-01

    Functional interplays of microbial activity, genetic diversity and contaminant transformation are poorly understood in reactors for mineralizing halogenated aromatics anaerobically. Here, we investigated abundance and distribution of potential microbes and functional genes associated with pentachlorophenol (PCP) anaerobic mineralization in a continuous-flow cylindrical reactor (15 cm in length). PCP dechlorination and the metabolite (phenol) were observed at segments 0–8 cm from inlet, where key microbes, including potential reductive dechlorinators (Dehalobacter, Sulfurospirillum, Desulfitobacterium and Desulfovibrio spp.) and phenol degraders (Cryptanaerobacter and Syntrophus spp.), as well as putative functional genes, including putative chlorophenol reductive dehalogenase (cprA) and benzoyl-CoA reductase (bamB), were highly enriched simultaneously. Five types of putative cprAs, three types of putative bamBs and seven types of putative nitrogenase reductase (nifHs) were determined, with their copy numbers decreased gradually from inlet to outlet. Distribution of chemicals, bacteria and putative genes confirmed PCP dechlorination and phenol degradation accomplished in segments 0–5 cm and 0–8 cm, respectively, contributing to a high PCP mineralization rate of 3.86 μM d−1. Through long-term incubation, dechlorination, phenol degradation and nitrogen fixation bacteria coexisted and functioned simultaneously near inlet (0–8 cm), verified the feasibility of anaerobic mineralization of halogenated aromatics in the compact reactor containing multiple functional microbes. PMID:26750760

  14. On the Effectiveness of Wastewater Cylindrical Reactors: an Analysis Through Steiner Symmetrization

    OpenAIRE

    Díaz Díaz, Jesús Ildefonso; Gómez-Castro, D.

    2015-01-01

    The mathematical analysis of the shape of chemical reactors is studied in this paper through the research of the optimization of its effectiveness g such as introduced by R. Aris around 1960. Although our main motivation is the consideration of reactors specially designed for the treatment of wastewaters our results are relevant also in more general frameworks. We simplify the modeling by assuming a single chemical reaction with a monotone kinetics leading to a parabolic equation with a non-n...

  15. Neutron spectrometry and dosimetry study at two research nuclear reactors using bonner sphere spectrometer (BSS), rotational spectrometer (ROSPEC) and cylindrical nested neutron spectrometer (NNS)

    International Nuclear Information System (INIS)

    Neutron spectrometry and subsequent dosimetry measurements were undertaken at the McMaster Nuclear Reactor (MNR) and AECL Chalk River National Research Universal (NRU) Reactor. The instruments used were a Bonner sphere spectrometer (BSS), a cylindrical nested neutron spectrometer (NNS) and a commercially available rotational proton recoil spectrometer. The purposes of these measurements were to: (1) compare the results obtained by three different neutron measuring instruments and (2) quantify neutron fields of interest. The results showed vastly different neutron spectral shapes for the two different reactors. This is not surprising, considering the type of the reactors and the locations where the measurements were performed. MNR is a heavily shielded light water moderated reactor, while NRU is a heavy water moderated reactor. The measurements at MNR were taken at the base of the reactor pool, where a large amount of water and concrete shielding is present, while measurements at NRU were taken at the top of the reactor (TOR) plate, where there is only heavy water and steel between the reactor core and the measuring instrument. As a result, a large component of the thermal neutron fluence was measured at MNR, while a negligible amount of thermal neutrons was measured at NRU. The neutron ambient dose rates at NRU TOR were measured to be between 0.03 and 0.06 mSv h-1, while at MNR, these values were between 0.07 and 2.8 mSv h-1 inside the beam port and -1 between two operating beam ports. The conservative uncertainty of these values is 15 %. The conservative uncertainty of the measured integral neutron fluence is 5 %. It was also found that BSS over-responded slightly due to a non-calibrated response matrix. (authors)

  16. Optical and electrical study of Ar-C2 H2 and N2-C2 H2 RF-excited plasmas in a small cylindrical reactor

    International Nuclear Information System (INIS)

    An optical and electrical investigation were carried out of organic plasmas obtained from DC and RF discharges in mixtures of Arc-C2 H2 in a small cylindrical reactor operating under pressures ranging from 0.3 to 1.0 Torr. The Actinometric Optical Emission Spectroscopy was used to follow the trends of C H and H species in the reactive plasma, for different pressures and power coupled to the reactor. The results showed a decreasing of C H concentration with the increasing of pressure and DC power and an increasing of the H concentration with the increasing of the pressure. The electrical investigation was performed using pulsed Langmuir probe technique, indicating typical electronic temperature around 2 eV. The effects of film deposition on the probe tip surface was analyzed using. Ar as reference gas. The results obtained indicated application of the probe during few period of sweep cycle. (author). 8 refs, 5 figs

  17. The Globe laid bare

    CERN Multimedia

    Fortunati, Lucien

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.

  18. Cylindrical Superlens

    CERN Document Server

    Yan, Min; Qiu, Min

    2008-01-01

    Cylinder-shaped perfect lens deduced from the coordinate transformation method is proposed. The previously reported perfect slab lens is noticed to be a limiting form of the cylindrical lens when the inner radius approaches infinite with respect to the lens thickness. Connaturality between a cylindrical lens and a slab lens with the same thickness and equivalent material parameters is affirmed by comparing their eigen-field transfer functions. We numerically confirm the subwavelength imaging capability of such a cylindrical lens with consideration of material imperfection. The advantages of a cylindrical lens include finite structure size and ability to image with magnification or demagnification. Besides subwavelength imaging, its invisibility property implies that a cylindrical lens may also be valuable for non-invasive electromagnetic probing applications.

  19. Calibration of the nuclear power channels for the cylindrical configuration of the IPEN/MB-01 reactor obtained from the measurements of the spatial neutron flux distribution in the reactor core through the irradiation of gold foils

    International Nuclear Information System (INIS)

    The activation foil is one of the most used techniques to obtain and compare nuclear parameters from the nuclear data libraries, given by a gamma spectrometry system. Through the measurements of activity induced in the foils, it is possible to determine the neutron flux profile exactly where it has been irradiated. The power level operation of the reactor is a parameter directly proportional to the average neutron flux in the core. The objective of this work is to obtain, for a cylindrical configuration, the power generation through a spatial thermal neutron flux distribution in the core of IPEN/MB-01 Reactor, by irradiating gold foils positioned symmetrically into the core. They are put in a Lucite plate which will not interfere in the analysis of the neutron flux, because of its low microscopic absorption cross section for the analyzed neutrons. The foils are irradiated with and without cadmium covered small plates, to obtain the thermal and epithermal neutron flux, through specific equations. The correlation between the average power neutron flux, as a result of the foil's irradiation, and the average power digital neutron flux of the nuclear power channels, allows the calibration of the nuclear channels of the reactor. This same correlation was done in 2008 with the reactor in a rectangular configuration, which resulted in a specific calibration of the power level operation. This calibration cannot be used in the cylindrical configuration, because the nuclear parameters could change, which may lead to a different neutron profile. Furthermore, the precise knowledge of the power neutron flux in the core also validates the mathematics used to calculate the power neutron flux. (author)

  20. Dynamics of the atmospheric pressure diffuse dielectric barrier discharge between cylindrical electrodes in roll-to-roll PECVD reactor

    Science.gov (United States)

    Starostin, Sergey A.; Welzel, Stefan; Liu, Yaoge; van der Velden-Schuermans, Bernadette; Bouwstra, Jan B.; van de Sanden, Mauritius C. M.; de Vries, Hindrik W.

    2015-07-01

    The high current diffuse dielectric barrier discharge (DBD) was operated in a bi-axial cylindrical electrode configuration using nitrogen, oxygen and argon gas flow with the addition of tetraethyl orthosilicate as precursor for silica-like film deposition. The behaviour of the transient plasma was visualized by means of fast imaging from two orthogonal directions. The formation and propagation (~3 × 104 m s-1) of lateral ionization waves with the transverse light emission structure similar to the low pressure glow discharge was observed at time scales below 1 µs. Despite plasma non-uniformity at nanosecond time scale the deposition process on the web-rolled polymer results in smooth well adherent films with good film uniformity and excellent gas diffusion barrier properties. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  1. Cylindrical wormholes

    International Nuclear Information System (INIS)

    It is shown that the existence of static, cylindrically symmetric wormholes does not require violation of the weak or null energy conditions near the throat, and cylindrically symmetric wormhole geometries can appear with less exotic sources than wormholes whose throats have a spherical topology. Examples of exact wormhole solutions are given with scalar, spinor and electromagnetic fields as sources, and these fields are not necessarily phantom. In particular, there are wormhole solutions for a massless, minimally coupled scalar field in the presence of a negative cosmological constant, and for an azimuthal Maxwell electromagnetic field. All these solutions are not asymptotically flat. A no-go theorem is proved, according to which a flat (or string) asymptotic behavior on both sides of a cylindrical wormhole throat is impossible if the energy density of matter is everywhere nonnegative.

  2. Effect of inlet azimuthal flow rate nonuniformity on the coolant flow in a nuclear reactor cylindrical manifold

    International Nuclear Information System (INIS)

    A technique for numerical solution of two-dimensional equations of liquid motion with flow-off among porous disks, simulating distributing header of nuclear reactor is presented. The equations were obtained by integrating Navier-Stokes equations according to header height. Liquid distribution for symmetrical flows withour rotation is of continuous character, described by asymptotic cubic parabola, which is supported by experimental data. The distributions result in qualitative distortion of the picture of averaged liquid flow in distributing headers. The occurrence of vortexes, which intensity can achieve considerable values and result in large decrease of selection rate in vortex region is noted. The selection rate can assume negative values (reverse flows) for the definite parameters of the header and intensive disturbances. It was concluded that the distributing header represents the intensifier of inlet hydraulic nonuniformity in wide range of header parameters and Reynolds numbers Vortex formation was not revealed in collecting header for time radial liquid outlet

  3. The Globe laid bare

    CERN Multimedia

    Anaïs Schaeffer

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.   The Globe after the removal of all the sun baffles. Image: Lucien Fortunati. Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are ...

  4. Neutron flux distribution inside the cylindrical core of minor excess of reactivity in the IPEN/MB-01 reactor and comparison with citation code and MCNP- 5 code

    International Nuclear Information System (INIS)

    This study aims to determine the distribution of thermal neutron flux in the IPEN/MB-01 nuclear reactor core assembled with cylindrical core configuration of minor excess of reactivity with 568 fuel rods (28 fuel rods in diameter). The thermal neutron flux at the positions of irradiation derive from the method of reaction rate using gold foils. The experiment consists in inserting gold activations foils with and without cadmium coverage (cadmium boxes with 0.0502 cm thickness) in several positions throughout the active core. After irradiation, activity induced by nuclear reaction rates over gold foils is assessed by gamma ray spectrometry using a high-purity germanium (HPGe) detector. Experimental results are compared to those derived from calculations performed using a three dimensional CITATION diffusion code and MCNP-5 code and a proper nuclear data library. While calculated neutron flux data shows good agreement with experimental values in regions with little disturbance in the neutron flux, also showing that in the region of the reflectors of neutrons and near the control rods, the diffusion theory is not very precise. The average value of thermal neutron flux obtained experimentally compared to the calculated value by CITATION code and MCNP-5 code respectively show a difference of 1.18% and 0.84% at a nuclear power level of 74.65 ± 3.28 % watts. The average measured value of thermal neutron flux is 4.10 108 ± 5.25% n/cm2s. (author)

  5. Neutron flux distribution inside the cylindrical core of minor excess of reactivity in the IPEN/MB-01 reactor and comparison with citation code and MCNP- 5 code

    Energy Technology Data Exchange (ETDEWEB)

    Aredes, Vitor Ottoni; Bitelli, Ulysses d' Utra; Mura, Luiz Ernesto C.; Santos, Diogo Feliciano dos; Lima, Ana Cecilia de Souza, E-mail: ubitelli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    This study aims to determine the distribution of thermal neutron flux in the IPEN/MB-01 nuclear reactor core assembled with cylindrical core configuration of minor excess of reactivity with 568 fuel rods (28 fuel rods in diameter). The thermal neutron flux at the positions of irradiation derive from the method of reaction rate using gold foils. The experiment consists in inserting gold activations foils with and without cadmium coverage (cadmium boxes with 0.0502 cm thickness) in several positions throughout the active core. After irradiation, activity induced by nuclear reaction rates over gold foils is assessed by gamma ray spectrometry using a high-purity germanium (HPGe) detector. Experimental results are compared to those derived from calculations performed using a three dimensional CITATION diffusion code and MCNP-5 code and a proper nuclear data library. While calculated neutron flux data shows good agreement with experimental values in regions with little disturbance in the neutron flux, also showing that in the region of the reflectors of neutrons and near the control rods, the diffusion theory is not very precise. The average value of thermal neutron flux obtained experimentally compared to the calculated value by CITATION code and MCNP-5 code respectively show a difference of 1.18% and 0.84% at a nuclear power level of 74.65 ± 3.28 % watts. The average measured value of thermal neutron flux is 4.10 10{sup 8} ± 5.25% n/cm{sup 2}s. (author)

  6. Effect of Gas/Water Ratio on the Performance of Combined Cylindrical Anoxic/Aerobic Moving Bed Biofilm Reactors for Biological Nutrients Removal from Domestic Wastewater by Fully Nitrification-Denitrification Processes

    OpenAIRE

    Husham T. Ibrahim; HEQiang; Wisaam S. Al-Rekabi

    2014-01-01

    In this research the continuously up-flow pilot scale Moving Bed Biofilm Reactor (MBBR) which was consists of combined cylindrical anoxic/aerobic MBBR in nested form with anoxic/aerobic volume ratio equal to 0.16 under fully nitrification-denitrification process were used to treated 4 m34+-N, TN and TP, respectively, while the average Dissolved Oxygen concentration (DO) in aerobic and anoxic MBBRs were 4.49 and 0.16 mg/L, respectively.

  7. Fotodegradación Solar Heterogénea a Escala Piloto de 4-Clorofenol en un Reactor Cilindro Parabólico Compuesto (CPC Pilot Scale Heterogeneous Solar Photodegradation of 4-Chlorophenol in a Cylindrical Parabolic Composed Reactor (CPC

    Directory of Open Access Journals (Sweden)

    Nhora Suaterna-Ortíz

    2012-01-01

    Full Text Available Se presenta información experimental para la fotodegradación heterogénea del 4-clorofenol con TiO2-P25, en reactores solares a escala piloto del tipo cilindro parabólico compuesto (CPC. Se evaluó el efecto del pH y la concentración de catalizador sobre el porcentaje de degradación del substrato. Los reactores utilizados tuvieron diferentes áreas y diferentes volúmenes totales de operación CPC-I: 1.16 m² de área y 20 L; CPC-II: 2.33 m² y 50 L; CPC-III: 3.50 m² y 60 L. Se realizó el seguimiento de la degradación por mediciones de ion cloruro, por espectrofotometría UV-Vis y la determinación de color verdadero. Se encontró que las variables de mayor influencia en el proceso fueron el pH y el área del reactor. Se evidenció la formación de sustancias intermediarias que aportaron color al sistema y la desaparición de éstas a medida que se incrementa el área de exposición solar.This study presented experimental information about heterogeneous photodegradation of 4-chlorophenol using TiO2-P25 in cylindrical parabolic composed solar reactor (CPC. The effect of pH and catalyst concentration on the degradation percentage of substrate were determined. The reactors have different areas and different total operating volumes: CPC-I: 1.16 m² de area y 20 L; CPC-II: 2.33 m² y 50 L; CPC-III: 3.50 m² y 60 L. The measurements were done using chloride ion, UV-spectrophotometry and color. It was found that the most influential variables on the process were the pH and the reactor area. Also, the formation of intermediary substances that provided color to the reaction system and the disappearance of them when sun exposure area was increased, were observed.

  8. Solid Bare Strange Quark Stars

    CERN Document Server

    Xu, R X

    2003-01-01

    The reason, we need three terms of `strange', `bare', and `solid' before quark stars, is presented concisely though some fundamental issues are not certain. Observations favoring these stars are introduced.

  9. The Bare Critical Assembly of Natural Uranium and Heavy Water

    International Nuclear Information System (INIS)

    The first reactor built in Yugoslavia was the bare zero energy heavy water and natural uranium assembly at the Boris Kidric Institute of Nuclear Sciences, Belgrade. The reactor went critical on April 29, 1958. The possession of four tons of natural uranium metal and the temporary availability of seven tons of heavy water encouraged the staff of the Institute to build a critical assembly. A critical assembly was chosen, rather than high flux reactor, because the heavy water was available only temporarily. Besides, a 10 MW, enriched uranium, research reactor is being built at the same Institute and should be ready for operation late this year. It was supposed that the zero energy reactor would provide experience in carrying out critical experiments, operational experience with nuclear reactors, and the possibility for an extensive program in reactor physics. (author)

  10. Effect of Gas/Water Ratio on the Performance of Combined Cylindrical Anoxic/Aerobic Moving Bed Biofilm Reactors for Biological Nutrients Removal from Domestic Wastewater by Fully Nitrification-Denitrification Processes

    Directory of Open Access Journals (Sweden)

    Husham T. Ibrahim

    2014-04-01

    Full Text Available In this research the continuously up-flow pilot scale Moving Bed Biofilm Reactor (MBBR which was consists of combined cylindrical anoxic/aerobic MBBR in nested form with anoxic/aerobic volume ratio equal to 0.16 under fully nitrification-denitrification process were used to treated 4 m34+-N, TN and TP, respectively, while the average Dissolved Oxygen concentration (DO in aerobic and anoxic MBBRs were 4.49 and 0.16 mg/L, respectively.

  11. Nitrogen and phosphorus removal of domestic sewage using luffa cylindrical sponge carrier sequencing batch biofilm reactor%丝瓜络填料SBBR对生活污水脱氮除磷的试验研究

    Institute of Scientific and Technical Information of China (English)

    王营章; 张尚华; 刘志强; 李洁

    2012-01-01

    利用丝瓜络填料序批式生物膜反应器(LS-SBBR)处理生活污水,研究了反应器对生活污水中NH3-N、TN、TP的去除效果以及生物相的变化情况等.试验结果表明:丝瓜络填料SBBR对生活污水中NH3-N、TN、TP的平均去除率分别为90%、78%、88%.说明丝瓜络填料SBBR适用于生活污水的脱氮除磷.%Luffa cylindrical sponge carrier sequencing batch biofilm reactor(LS-SBBR) has been used for treating domestic wastewater. The removing effects of the reactor on NH3-N, TN, TP in domestic water are studied. The results show that the average removal rates of NH3-N,TN and TP reach 90% ,78% and 88% respectively,indicating that the luffa cylindrical sponge carrier SBBR is very suitable for the removal of nitrogen and phosphorus from domestic sewage.

  12. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  13. Measurement of dose rate profile and spectra through a cylindrical duct vis-a-vis Monte Carlo simulation studies for optimisation of reactor shield design

    International Nuclear Information System (INIS)

    In the design of a nuclear reactor, penetrations are provided in the top shield to carry out some essential operations. Radiation streaming is envisaged through such penetrations. To avoid radiation streaming, complementary shielding is provided. Optimisation of complementary shielding is carried out by performing calculations using MCNP code. Uncertainties in the calculations are taken care of by incorporating a safety factor. The assumption of the safety factor, while designing the reactor shielding, has been validated by undertaking experimental measurements on a similar geometry vis-a-vis the computed values obtained using MCNP code. The results of the present work agree with the safety factor of two assumed during the shield design. The details of gamma spectral measurements carried out with high purity germanium detector to understand the pattern of the scattered spectrum are also presented

  14. Dynamic study of thin cylindrical vessels

    International Nuclear Information System (INIS)

    Fluids essential for the safety of a nuclear reactor (water, boron...) are contained in thin cylindrical vessels. An experimental investigation of the dynamic buckling of a thin cylindrical vessel filled with a fluid has been carried out on a shaking table. An investigation of the frequencies and mode shape of the vessel had also been done prior to the test. Calculations performed in order to predict these frequencies and modes have shown the importance of taking into account the stiffening effect of the fluid static pressure

  15. Very Late Bare Metal Stent Thrombosis

    Directory of Open Access Journals (Sweden)

    Mariana Soto Herrera

    2013-01-01

    Full Text Available Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation.

  16. Very Late Bare Metal Stent Thrombosis

    Science.gov (United States)

    Soto Herrera, Mariana; Restrepo, José A.; Felipe Buitrago, Andrés; Gómez Mejía, Mabel; Díaz, Jesús H.

    2013-01-01

    Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation. PMID:24829831

  17. Bare Higgs mass at Planck scale

    CERN Document Server

    Hamada, Yuta; Oda, Kin-ya

    2013-01-01

    In a certain quantum gravity/string theory context, it is possible that not only the physical Higgs mass but also the bare one (and hence the radiative corrections as well) can vanish at the Planck/string scale. We compute one and two loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model (SM). We approximate the bare couplings at the ultraviolet cutoff scale by the MSbar ones at the same scale, which we evaluate for the Higgs mass around 126GeV in the SM. We obtain the cutoff scale dependence of the bare Higgs mass up to two loop orders, and examine where it becomes zero. We find that if we take the current central value for the top quark pole mass, 173GeV, the bare Higgs mass vanishes at about 10^{23}GeV. With a 1.3 sigma smaller mass, 170GeV, the scale can be of the order of the Planck scale.

  18. Cylindrical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  19. Neutron measurements at nuclear power reactors [55

    CERN Document Server

    Scherpelz, R I

    2002-01-01

    Staff from the Pacific Northwest National Laboratory (operated by Battelle Memorial Institute), have performed neutron measurements at a number of commercial nuclear power plants in the United States. Neutron radiation fields at light water reactor (LWR) power plants are typically characterized by low-energy distributions due to the presence of large amounts of scattering material such as water and concrete. These low-energy distributions make it difficult to accurately monitor personnel exposures, since most survey meters and dosimeters are calibrated to higher-energy fields such as those produced by bare or D sub 2 O-moderated sup 2 sup 5 sup 2 Cf sources. Commercial plants typically use thermoluminescent dosimeters in an albedo configuration for personnel dosimetry and survey meters based on a thermal-neutron detector inside a cylindrical or spherical moderator for dose rate assessment, so their methods of routine monitoring are highly dependent on the energy of the neutron fields. Battelle has participate...

  20. The analytic nodal method in cylindrical geometry

    International Nuclear Information System (INIS)

    Nodal diffusion methods have been used extensively in nuclear reactor calculations, specifically for their performance advantage, but also for their superior accuracy. More specifically, the Analytic Nodal Method (ANM), utilising the transverse integration principle, has been applied to numerous reactor problems with much success. In this work, a nodal diffusion method is developed for cylindrical geometry. Application of this method to three-dimensional (3D) cylindrical geometry has never been satisfactorily addressed and we propose a solution which entails the use of conformal mapping. A set of 1D-equations with an adjusted, geometrically dependent, inhomogeneous source, is obtained. This work describes the development of the method and associated test code, as well as its application to realistic reactor problems. Numerical results are given for the PBMR-400 MW benchmark problem, as well as for a 'cylindrisized' version of the well-known 3D LWR IAEA benchmark. Results highlight the improved accuracy and performance over finite-difference core solutions and investigate the applicability of nodal methods to 3D PBMR type problems. Results indicate that cylindrical nodal methods definitely have a place within PBMR applications, yielding performance advantage factors of 10 and 20 for 2D and 3D calculations, respectively, and advantage factors of the order of 1000 in the case of the LWR problem

  1. Bare nominals and reference to capacities

    NARCIS (Netherlands)

    Swart, Henriëtte de; Winter, Y.; Zwarts, J.

    2007-01-01

    Prefinal version. This paper concentrates on the syntax and semantics of bare nominals in Germanic and Romance languages. These languages do not normally allow nominals to occur without an article. However, some syntactic configurations, including predicative constructions, supplementives and some p

  2. Zero energy reactor 'RB'

    International Nuclear Information System (INIS)

    In 1958 the zero energy reactor RB was built with the purpose of enabling critical experiments with various reactor systems to be carried out. The first core assembly built in this reactor consists of heavy water as moderator and natural uranium metal as fuel. In order to be able to obtain very accurate results when measuring the main characteristics of the assembly the reactor was built as a completely bare system. (author)

  3. Reactors

    International Nuclear Information System (INIS)

    Purpose: To provide a spray cooling structure wherein the steam phase in a bwr reactor vessel can sufficiently be cooled and the upper cap and flanges in the vessel can be cooled rapidly which kept from direct contaction with cold water. Constitution: An apertured shielding is provided in parallel spaced apart from the inner wall surface at the upper portion of a reactor vessel equipped with a spray nozzle, and the lower end of the shielding and the inner wall of the vessel are closed to each other so as to store the cooling water. Upon spray cooling, cooling water jetting out from the nozzle cools the vapor phase in the vessel and then hits against the shielding. Then the cooling water mostly falls as it is, while partially enters through the apertures to the back of the shielding plate, abuts against stoppers and falls down. The stoppers are formed in an inverted L shape so that the spray water may not in direct contaction with the inner wall of the vessel. (Horiuchi, T.)

  4. Thermal Photons From Magnetized Bare Strange Stars

    CERN Document Server

    Méndez, Enrique Moreno; Patiño, Leonardo; Ortega, Patricia

    2013-01-01

    A plasma made out of strange-quark matter (SQM) and electrons, has a rather high plasma frequency (>20 MeV). Thus, a compact star made of such material all the way up to its surface, i.e., a bare strange star, would be unable to radiate away its thermal emission. We use the MIT-bag model and assume that SQM is the ground state of nuclear matter at high density. We investigate whether the presence of a magnetic field will allow propagation of radiation at frequencies below the SQM plasma frequencies. Hence, we study the presence of gyrofrequencies in a SQM plasma permeated by a strong magnetic field (B > 10^{12} G). We find that small regions in the frequency spectrum allow radiation propagation due to the presence of the magnetic fields. It is likely that narrow bands of radiation would likely be observable from magnetized bare strange stars .

  5. Bare metal stenting of the iliac arteries.

    Science.gov (United States)

    Kim, Tanner I; Schneider, Peter A

    2016-06-01

    A significant subset of patients with peripheral artery disease (PAD) has iliac artery involvement that requires treatment. The development of bare metal stents has improved the short- and long-term outcomes of endovascular repair and has become first line therapy. Open surgical bypass has been reserved for extremely complex anatomic morphologies or endovascular failures. It is unclear whether primary stenting is superior to angioplasty with provisional stenting but if angioplasty is used alone, it is likely only appropriate for the most focal lesions. Self-expanding and balloon-expandable stents have unique characteristics that are suitable to different lesion morphologies. Both stent-types have demonstrated similar outcomes. Herein, we review the practice and results of bare metal stents in the iliac arteries. PMID:27035892

  6. Water Accommodation on Bare and Coated Ice

    Science.gov (United States)

    Kong, Xiangrui

    2015-04-01

    A good understanding of water accommodation on ice surfaces is essential for quantitatively predicting the evolution of clouds, and therefore influences the effectiveness of climate models. However, the accommodation coefficient is poorly constrained within the literature where reported values vary by up to three orders of magnitude. In addition, the complexity of the chemical composition of the atmosphere plays an important role in ice phase behavior and dynamics. We employ an environmental molecular beam (EMB) technique to investigate molecular water interactions with bare and impurity coated ice at temperatures from 170 K to 200 K. In this work, we summarize results of water accommodation experiments on bare ice (Kong et al., 2014) and on ice coated by methanol (Thomson et al., 2013), butanol (Thomson et al., 2013) and acetic acid (Papagiannakopoulos et al., 2014), and compare those results with analogous experiments using hexanol and nitric acid coatings. Hexanol is chosen as a complementary chain alcohol to methanol and butanol, while nitric acid is a common inorganic compound in the atmosphere. The results show a strong negative temperature dependence of water accommodation on bare ice, which can be quantitatively described by a precursor model. Acidic adlayers tend to enhance water uptake indicating that the system kinetics are thoroughly changed compared to bare ice. Adsorbed alcohols influence the temperature dependence of the accommodation coefficient and water molecules generally spend less time on the surfaces before desorbing, although the measured accommodation coefficients remain high and comparable to bare ice for the investigated systems. We conclude that impurities can either enhance or restrict water uptake in ways that are influenced by several factors including temperature and type of adsorbant, with potential implications for the description of ice particle growth in the atmosphere. This work was supported by the Swedish Research Council and

  7. Ikke bare porno på mobilen

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    2013-01-01

    Den britiske børne- og ungdomsforsker professor Sonia Livingstone ved London School of Economics viser gennem en række interviews, at billeder af eksplicitte sexhandlinger er en velkendt del af den ungdommelige cirkulation af ’hverdagspornografisk’ materiale (Ringrose et al. 2012). ’Sexting’ er a...... altså ikke bare porno på en mobilplatform. Det er handlinger og værgestrategier, som unge piger er nødt til at forholde sig til i hverdagen, mens drengene umiddelbart ser ud til at slippe relativt let udenom den chikane, der kan ligge i ’sexting’....

  8. A friendly Maple module for one and two group reactor model

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Camila O.; Pavan, Guilherme A.; Braga, Kelmo L.; Silva, Marcelo V.; Pereira, P.G.S.; Werner, Rodrigo; Antunes, Valdir; Vellozo, Sergio O., E-mail: camila.oliv.baptista@gmail.com, E-mail: pavanguilherme@gmail.com, E-mail: kelmo.lins@gmail.com, E-mail: marcelovilelasilva@gmail.com, E-mail: rodrigowerner@hotmail.com, E-mail: neutron201566@yahoo.com, E-mail: vellozo@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear

    2015-07-01

    The well known two energy groups core reactor design model is revisited. A simple and friendly Maple module was built to cover the steps calculations of a plate reactor in five situations: 1. one group bare reactor, 2. two groups bare reactor, 3. one group reflected reactor, 4. 1-1/2 groups reflected reactor and 5. two groups reflected reactor. The results show the convergent path of critical size, as it should be. (author)

  9. Magnetospheric activity of bare strange quark stars

    Science.gov (United States)

    Yu, J. W.; Xu, R. X.

    2011-06-01

    In the model of Ruderman and Sutherland, the binding energy problem is a severe problem when modelling normal neutron stars as pulsars, i.e. both ions (e.g. 5626Fe) and electrons on the normal neutron star surface can be pulled out freely by the unipolar generator induced electric field, so that sparking on the polar cap can hardly occur. This problem can be solved within the partially screened gap (PSG) model for neutron stars. However, in this paper, we study this problem extensively in a model of bare strange quark stars (BSSs). We find that the huge potential barrier built by the electric field in the vacuum gap above the polar cap can usually prevent electrons from streaming into the magnetosphere, unless the electric potential of a pulsar is sufficiently lower than that at the infinite interstellar medium. Other processes, such as the diffusion and thermionic emission of electrons, have also been included here. Our conclusions are as follows. Both positive and negative particles on the surface of a BSS are bound strongly enough to form a vacuum gap above its polar cap as long as the BSS is not charged (or not highly negative charged), and multi-accelerators can occur in the magnetosphere of the BSS. Our results may be helpful to distinguish normal neutron stars and bare quark stars using a pulsar's magnetospheric activities.

  10. Measurement of cylindrical parts

    Science.gov (United States)

    Knight, Paul Douglas, Jr.

    The form of cylindrical parts has been traditionally evaluated using stylus-based mechanical instruments. The Tropel Corporation has developed a grazing incidence interferometer (GII) for the measurement of cylindrical parts. The repeatability of this instrument due to various instrument uncertainties was measured. Differing instrument configurations that produce the same systematic error were determined to produce a zonal calibration method for determining systematic error over the full range of the instrument, given knowledge of the error in a single zone. The effect of the aperture stop on the response of the imaging system to axially sinusoidal artifacts was simulated. Diamond-turned axially sinusoidal artifacts, with amplitude of order1 um and spatial wavelength of order10 mm, were measured to test the axial response of the interferometer. The modulation transfer function of the instrument's imaging system, measured using a knife edge test, predicts the response observed with the sinusoidal artifacts. A diffraction analysis predicts that the measured axial form is modified by a second order envelope function with phase that varies with the relative position of the imaging system focal plane and part position. A compensation method is proposed for this effect. A comparison of roundness measurements by both a traditional stylus-based instrument and the GII was performed demonstrating that the roundness measurements of the two instruments are equivalent when the measurements are properly corrected for the differing effects of surface finish.

  11. Cylindrical laser welder

    Science.gov (United States)

    Honeycutt, T. E.; Roberts, T. G.

    1986-05-01

    Brass retainer rings are currently fastened to artillery shells by spinning each shell at a high rate and then jamming the ring on it so that it is fastened or welded by friction between the two objects. This is an energy-inefficient process which heats and weakens more material than is desirable. The shell spinning at a high rate is also potentially dangerous. A laser welder is provided that generates output energy focused on a circular or cylindrical shape for simultaneously welding around a 360 degs circumference without unnecessarily heating large amounts of material. The welder may be used to fasten cylindrical shaped objects, gears and shafts together, which is difficult to do by conventional means. The welder may also be used to fasten one cylinder to another. To accomplish the welding, a laser has an unstable optical cavity arranged with its feedback mirror centered to generate a circular output beam having an obscuration in the center. A circularly-symmetric, off-axis concave mirror focuses the output beam onto the objects being fastened and away from the center line or axis of the circular beam.

  12. Thermalization Calculations in a Cylindrical Shell

    International Nuclear Information System (INIS)

    An approximate, semi-analytical procedure for determining the distribution and energy spectrum of the thermal and epithermal neutron flux in a weakly neutron capturing, cylindrical shell medium is considered. The shell medium is taken to represent the moderator surrounding a fuel rod in a thermal reactor. The basis for calculating the flux in most of the moderator is the energy-dependent diffusion equation. Transient corrections to the diffusion approximation are added near the medium boundaries. The effects of adjoining media are taken into account through the boundary conditions imposed on the diffusion and transient fluxes. At the inner boundary these effects are calculated by collision probability methods. Activation fluxes are derived from the calculated neutron flux distributions and compared with measurements made in the D2O moderator surrounding a uranium metal rod in the ZEEP reactor. (author)

  13. Suzaku observations of 'bare' active galactic nuclei

    CERN Document Server

    Walton, D J; Fabian, A C; Gallo, L C; Reis, R C

    2012-01-01

    We present a X-ray spectral analysis of a large sample of 25 'bare' active galactic nuclei, sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from relativistic disc reflection, and examining the implications of this interpretation for the intrinsic spectral complexities frequently displayed by AGN in the X-ray bandpass. During the analysis, we take the unique approach of attempting to simultaneously undertake a systematic analysis of the whole sample, as well as a detailed treatment of each individual source, and find that disc reflection has the required flexibility to successfully reproduce the broadband spectrum observed for all of the sources considered. Where possible, we use the reflected emission to place constraints on the black hole spin for this sample of sources. Our analysis suggests a general preference for rapidly rotating black holes, which if taken at face value is most consistent with the scenario in whic...

  14. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  15. Annual report of STACY in 1995. 600mm diameter cylindrical core and 10% enriched uranyl nitrate solution

    International Nuclear Information System (INIS)

    STACY, a critical assembly for static criticality safety experiments in NUCEF, had achieved the first criticality on February 23, 1995, with a 600mm diameter cylindrical core tank and 10% enriched uranyl nitrate solution. Since then, 56 experiments were performed with various conditions of fuel concentration and reflecting conditions: bare and water. Operation data of STACY in 1995 are summarized in this report. (author)

  16. Cylindrical rotating triboelectric nanogenerator.

    Science.gov (United States)

    Bai, Peng; Zhu, Guang; Liu, Ying; Chen, Jun; Jing, Qingshen; Yang, Weiqing; Ma, Jusheng; Zhang, Gong; Wang, Zhong Lin

    2013-07-23

    We demonstrate a cylindrical rotating triboelectric nanogenerator (TENG) based on sliding electrification for harvesting mechanical energy from rotational motion. The rotating TENG is based on a core-shell structure that is made of distinctly different triboelectric materials with alternative strip structures on the surface. The charge transfer is strengthened with the formation of polymer nanoparticles on surfaces. During coaxial rotation, a contact-induced electrification and the relative sliding between the contact surfaces of the core and the shell result in an "in-plane" lateral polarization, which drives the flow of electrons in the external load. A power density of 36.9 W/m(2) (short-circuit current of 90 μA and open-circuit voltage of 410 V) has been achieved by a rotating TENG with 8 strip units at a linear rotational velocity of 1.33 m/s (a rotation rate of 1000 r/min). The output can be further enhanced by integrating more strip units and/or applying larger linear rotational velocity. This rotating TENG can be used as a direct power source to drive small electronics, such as LED bulbs. This study proves the possibility to harvest mechanical energy by TENGs from rotational motion, demonstrating its potential for harvesting the flow energy of air or water for applications such as self-powered environmental sensors and wildlife tracking devices. PMID:23799926

  17. New optical cylindrical microresonators

    Science.gov (United States)

    Gun'ko, Yurii K.; Balakrishnan, Sivakumar; McCarthy, Joseph E.; Rakovich, Yuri P.; Donegan, John F.; Perova, Tatiana S.; Melnikov, Vasily

    2007-10-01

    In this paper we describe a novel technique for the fabrication of aluminosilicate microfibres and microtubes which are shown to act as optical cylindrical microresonators. The alumosilicate microfibres and microtubes were fabricated by using vacuum-assisted wetting and filtration of silica gel through a microchannel glass matrix. The microfibres and microtubes were studied using Scanning Electron Microscopy (SEM), micro-photoluminescence spectroscopy and fluorescence lifetime imaging confocal microscopy. In the emission spectra of the micro-resonators we find very narrow periodic peaks corresponding to the whispering gallery modes of two orthogonal polarizations with quality factors up to 3200. A strong enhancement in photoluminescence decay rates at high excitation power demonstrates the occurrence of amplified spontaneous emission from a single microtube. These microtubes show a large evanescent field extending many microns beyond the tube radius. Potential applications for these novel microresonators will be in the area of optical microsensors for a single molecule detection of biological and chemical species, including anti-terrorism and defense sectors.

  18. Pair emission from bare magnetized strange stars

    CERN Document Server

    Melrose, D B; Peres-Menezes, D

    2006-01-01

    The dominant emission from bare strange stars is thought to be electron-positron pairs, produced through spontaneous pair creation (SPC) in a surface layer of electrons tied to the star by a superstrong electric field. The positrons escape freely, but the electrons are directed towards the star and quickly fill all available states, such that their degeneracy suppresses further SPC. An electron must be reflected and gain energy in order to escape, along with the positron. Each escaping electron leaves a hole that is immediately filled by another electron through SPC. We discuss the collisional processes that produce escaping electrons. When the Landau quantization of the motion perpendicular to the magnetic field is taken into account, electron-electron collisions can lead to an escaping electron only through a multi-stage process involving higher Landau levels. Although the available estimates of the collision rate are deficient in several ways, it appears that the rate is too low for electron-electron colli...

  19. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  20. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  1. Reduction of Rhizoctonia bare patch win wheat with barley rotations.

    Science.gov (United States)

    Rhizoctonia bare patch caused by Rhizoctonia solani AG-8 is a major fungal root disease in no-till cropping systems. In an 8-year experiment comparing various dryland no-till cropping systems near Ritzville, Washington, Rhizoctonia bare patch first appeared in year 3 and continued through year 8. ...

  2. Optimization of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.

  3. IVA2 - a computer code for modelling of transient 3D-three phase three component flows using three velocity fields in cylindrical geometry with arbitrary internals including nuclear reactor PWR/BWR-core

    International Nuclear Information System (INIS)

    This report contains a formal code description (description of the input data, contents of the COMMON blocks, functions of the IVA2/001 routines). In addition the nonformal description of the current IVA2/001 constitutive package and the reactor core model are given. (orig.)

  4. An approach to cylindrical approximation of toroidal geometry

    International Nuclear Information System (INIS)

    Neutron transport processes in Tokamak fusion devices are described with same mathematical equipment as that used in fission reactor calculations. The aim of this paper is to show some of these methods in toroidal geometry problem. A new approach to cylindrical approximation is described. All calculations are performed by ANISN one-dimensional Sn code. To validate the present method, comparison have been done with Monte Carlo results, as well as with calculations done on previous geometry approximation (author)

  5. Cylindrical acoustic levitator/concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Kaduchak, Gregory (Los Alamos, NM); Sinha, Dipen N. (Los Alamos, NM)

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  6. EAARL Coastal Topography--Pearl River Delta 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely...

  7. EAARL Topography-Vicksburg National Millitary Park 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Vicksburg National Military Park in Mississippi was produced from remotely...

  8. EAARL Coastal Topography--Chandeleur Islands, Louisiana, 2010: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the Chandeleur Islands, Louisiana, was produced from remotely...

  9. EAARL Bare Earth Topography-Fire Island National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of Fire Island National Seashore was produced from remotely-sensed,...

  10. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northern Gulf of Mexico barrier islands and Naval Live Oaks was produced from...

  11. EAARL Coastal Topography--Northeast Barrier Islands 2007: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northeast coastal barrier islands in New York and New Jersey was produced from...

  12. Bare and effective fluid description in brane world cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Casilla 307, Santiago (Chile); Lepe, Samuel; Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile)

    2010-03-15

    An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fluid can cross the barrier {omega} {sub eff}=-1. (orig.)

  13. PHOTOCATALYTIC CYANIDE REMOVAL USING TiO2, FeMoO4/TiO2, AND HPMoCu/TiO2 CATALYSTS UNDER SIMULATED SOLAR LIGHT AND PARABOLIC CYLINDRICAL COLLECTOR REACTOR

    OpenAIRE

    Aida L. Barbosa; Isel Castro

    2012-01-01

    The purpose of this work, was to synthesis TiO2-doped (NH4)4[CuH6Mo6O24].5H2O and FeMoO4 catalysts, to improve TiO2 response against visible light, analyzing the influence of system degradation configuration, camera Suntest system CPS+ and PCCR reactor in kinetic parameters of cyanide removal. We conclude that Fe and Cu addition increased anatase phase percentage in TiO2, improved its visible absorption, and its energy band gap decreased. When FeMoO4 was used, this eliminated 87% of cyanide i...

  14. WEIR COEFFICIENT FOR CYLINDRICAL WEIRS

    Directory of Open Access Journals (Sweden)

    Senayi DÖNMEZ

    2002-01-01

    Full Text Available In this study, the weir coefficient for cylindrical weirs was experimentally investigated. Experiments were conducted for both free and submerged overflow conditions. Experimental results have indicated that the weir coefficient is about 3.50-3.80 for the free overflow condition. The weir coefficient for the submerged overflow condition varies with the amount of submergence.

  15. Optics Demonstrations Using Cylindrical Lenses

    Science.gov (United States)

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  16. On the definition of cylindrical symmetry

    OpenAIRE

    Carot, J.; Senovilla, J. M. M.; Vera, R

    1999-01-01

    The standard definition of cylindrical symmetry in General Relativity is reviewed. Taking the view that axial symmetry is an essential pre-requisite for cylindrical symmetry, it is argued that the requirement of orthogonal transitivity of the isometry group should be dropped, this leading to a new, more general definition of cylindrical symmetry. Stationarity and staticity in cylindrically symmetric spacetimes are then defined, and these issues are analysed in connection with orthogonal trans...

  17. Quantum Solitons with Cylindrical Symmetry

    OpenAIRE

    Chepilko, N.; Kobushkin, A.; Syamtomov, A.

    1993-01-01

    Soliton solutions with cylindrical symmetry are investigated within the nonlinear $\\sigma $-model disregarding the Skyrme-stabilization term. The solitons are stabilized by quantization of collective breathing mode and collapse in the $\\hbar \\to 0$ limit. It is shown that for such stabilization mechanism the model, apart from solitons with integer topological number $B$, admits the solitons with half-odd $B$. The solitons with integer $B$ have standard spin-isospin classification, while $B={\\...

  18. Laser welding of cylindrical parts

    OpenAIRE

    Närhi-Ratkovskaia, Olga

    2011-01-01

    The purpose of this paper is to conduct the laser welding work of the cylindrical parts, particularly fuel filters, according to the safety instructions. The welding was followed by the additional test for a gas resistance of filters. The topic was commissioned by the company Laserplus Oy, located in Hämeenlinna. The aim of the project on laser welding of filters was to find out optimum parameters for the company’s welding. Optimum parameters include the minimum laser power with optimum ...

  19. Cylindrical Collapse and Gravitational Waves

    CERN Document Server

    Herrera, L

    2005-01-01

    We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non zero on the surface of the cylinder and proportional to the time dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation - though non-gravitational - in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.

  20. Relativistically expanding cylindrical electromagnetic fields

    OpenAIRE

    Gourgouliatos, K. N.

    2009-01-01

    We study relativistically expanding electromagnetic fields of cylindrical geometry. The fields emerge from the side surface of a cylinder and are invariant under translations parallel to the axis of the cylinder. The expansion velocity is in the radial direction and is parametrized by $v=R/(ct)$. We consider force-free magnetic fields by setting the total force the electromagnetic field exerts on the charges and the currents equal to zero. Analytical and semi-analytical separable solutions ar...

  1. Semantic coherence in English accusative-with-bare-infinitive constructions

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2013-01-01

    Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative-with-bare-infinitive constru......Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative......-with-bare-infinitive construction. The main methodological framework is that of covarying collexeme analysis, which, through statistical corpus analysis, allows for the analyst to address the semantics of a construction. Using this method on data from the BNC, the ultimate purpose of the paper is to address the underlying semantic...... relations of English accusatives-with-bare-infinitives through the relations of semantic coherence between the two VPs....

  2. Evaluation of research reactors

    International Nuclear Information System (INIS)

    The present status of research reactors with highly enriched (93%) uranium fuel at JAERI, JRR-2 and JMTR is described. JRR-2 is a heterogeneous type of reactor, using heavy water as moderator and coolant. It uses both MTR type and cylindrical type of fuel elements. The maximum thermal power and the thermal neutron flux are 10 MW and 2x1014 n/cm2 see respectively. The reactor has been used for various experiments such as solid state physics, material irradiation, reactor fuel irradiation and radioisotope production. The JMTR is a multi-purpose tank type material testing reactor, and light water moderator and coolant, operated at 50 MW. The evaluation of lower enriched fuel and its consequences for both reactors is considered more especially

  3. Plastic buckling of cylindrical shells

    International Nuclear Information System (INIS)

    Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even though such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-thickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. in order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space Company. The analysis was performed for various radius-to-thickness ratios and imperfection amplitudes. The purpose of the analytical program was to compute the buckling strength of underground cylindrical tanks, that are used for storage of nuclear wastes, for realistic geometric imperfections and internal pressure loads. This paper presents the results of the elastic-plastic analyses and compares them with other available information for various pressure loads

  4. An analytical benchmark of MYRRHA ADS in cylindrical geometry

    International Nuclear Information System (INIS)

    In this study, the steady and transient neutronic behaviour of MYRRHA ADS is investigated. For this purpose, a recently proposed analytical benchmark of the diffusion kinetics as 1D slab model of the MYRRHA ADS concept developed in Belgium has been extended to the cylindrical geometry which represents the system more realistically. Analytical calculations are performed using the Customized Solution Method and numerical Laplace inversion techniques such as Fixed-Talbot and Gaver-Wynn-Rho algorithms. Results are compared with the finite element program FLEXPDE registered and they are found to be in complete agreement. The necessity of modeling the MYRHHA reactor in cylindrical geometry rather than slab geometry to obtain more realistic benchmark results is demonstrated. (orig.)

  5. RESEARCH ON THE CYLINDRICAL PARTICULATE FLOWS

    Institute of Scientific and Technical Information of China (English)

    LIN Jian-zhong

    2005-01-01

    The study of cylindrical particulate flows has wide industrial applicability and hence received much attention. The purpose of the present paper is to provide a review on the motion of cylindrical particles in shear layer, converging channel and jet flows, the dynamic of cylindrical particles sedimentation in a Newtonian fluid, the characterization of turbulent cylindrical particulate flows, the property of interaction between the particles, the structural feature and rheology of suspensions, the analysis of hydrodynamic instability of cylindrical particle suspensions. Finally, the concluding remarks are given.

  6. A proposed bare tether experiment on board a sounding rocket

    OpenAIRE

    Fujii, Hironori; OYAMA, Kohichiro; Sasaki, Susumu; Yamagiwa, Yoshiki; Cho, Mengu; Sanmartín Losada, Juan Ramón; Charro, Mario; Heide, Erik J. van der; Kruijff, Michiel; Lebreton, Jean-Pierre; Hilgers, Alain

    2005-01-01

    A sounding rocket experiment is proposed to carry out two experiments by the conductive bare-tether; 1) the test of the OML (Orbital-Motion-Limited) theory to collect electron, and II) the test of techniques to determine (neutral) density profile in critical E-layer. The main driver of the mission is provide a space tether technology experiment in low-Earth-Orbit (LEO) deploying a long tape tether in space and verify the performance of the bare electrodynamic tape tether. The sounding rocket ...

  7. Integral nuclear reactor

    International Nuclear Information System (INIS)

    The invention deals with an inprovement of the design of an integral pressurized water nuclear reactor. A typical embodyment of the invention includes a generally cylindrical pressure vessel that is assembled from three segments which are bolted together at transverse joints to form a pressure tight unit that encloses the steam generator and the reactor. The new construction permits primary to secondary coolant heat exchange and improved control rod drive mecanisms which can be exposed for full service access during reactor core refueling, maintenance and inspection

  8. Bare Higgs mass and potential at ultraviolet cutoff

    CERN Document Server

    Hamada, Yuta; Oda, Kin-ya

    2013-01-01

    We first review the current status of the top mass determination paying attention to the difference between the MS-bar and pole masses. Then we present our recent result on the bare Higgs mass at a very high ultraviolet cutoff scale.

  9. BARE retrotransposons are translated and replicated via distinct RNA pools.

    Directory of Open Access Journals (Sweden)

    Wei Chang

    Full Text Available The replication of Long Terminal Repeat (LTR retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.

  10. Basic science of nuclear medicine the bare bone essentials

    CERN Document Server

    Lee, Kai H

    2015-01-01

    Through concise, straightforward explanations and supporting graphics that bring abstract concepts to life, the new Basic Science of Nuclear Medicine—the Bare Bone Essentials is an ideal tool for nuclear medicine technologist students and nuclear cardiology fellows looking for an introduction to the fundamentals of the physics and technologies of modern day nuclear medicine.

  11. Solution of the multigroup analytic nodal diffusion equations in 3-dimensional cylindrical geometry / Rian Hendrik Prinsloo

    OpenAIRE

    Prinsloo, Rian Hendrik

    2006-01-01

    Nodal diffusion methods have been used extensively in nuclear reactor calculations specifically for their performance advantage, but also their superior accuracy. In this work a nodal diffusion method is developed for three-dimensional cylindrical geometry. Recent developments in the Pebble Bed Modular Reactor (PBMR) project have sparked renewed interest in the application of different modelling methods to its design, and naturally included in this effort is a nodal method for ...

  12. Evaluation of Bare Ground on Rangelands using Unmanned Aerial Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge; Maxine Dakins

    2011-01-01

    Attention is currently being given to methods that assess the ecological condition of rangelands throughout the United States. There are a number of different indicators that assess ecological condition of rangelands. Bare Ground is being considered by a number of agencies and resource specialists as a lead indicator that can be evaluated over a broad area. Traditional methods of measuring bare ground rely on field technicians collecting data along a line transect or from a plot. Unmanned aerial vehicles (UAVs) provide an alternative to collecting field data, can monitor a large area in a relative short period of time, and in many cases can enhance safety and time required to collect data. In this study, both fixed wing and helicopter UAVs were used to measure bare ground in a sagebrush steppe ecosystem. The data were collected with digital imagery and read using the image analysis software SamplePoint. The approach was tested over seven different plots and compared against traditional field methods to evaluate accuracy for assessing bare ground. The field plots were located on the Idaho National Laboratory (INL) site west of Idaho Falls, Idaho in locations where there is very little disturbance by humans and the area is grazed only by wildlife. The comparison of fixed-wing and helicopter UAV technology against field estimates shows good agreement for the measurement of bare ground. This study shows that if a high degree of detail and data accuracy is desired, then a helicopter UAV may be a good platform. If the data collection objective is to assess broad-scale landscape level changes, then the collection of imagery with a fixed-wing system is probably more appropriate.

  13. Buckling Characteristics of Cylindrical Pipes

    Institute of Scientific and Technical Information of China (English)

    Toshiaki Sakurai

    2015-01-01

    This paper describes the buckling pattern of the body frame by energy absorbed efficiency of crashworthiness related toresearch of the buckling characteristics of aluminum cylindrical pipes with various diameters formed mechanical tools. Experimentswere performed by the quasi-static test without lubrication between specimen and equipment. According to the change in the radiusversus thickness of the specimen, the buckling phenomena are transformed from folding to bellows and the rate of energy absorptionis understood. In crashworthiness, frames are characterized by the folding among three patterns from the absorbed energy efficiencypoint of view and weight reduction. With the development of new types of transport such as electric vehicles, innovated bodystructure should be designed.

  14. Heat transfer profiles of a vertical, bare, 7-element bundle cooled with supercritical Freon-12

    International Nuclear Information System (INIS)

    Experimental data on SuperCritical-Water (SCW) cooled bundles are very limited. However, SuperCritical Water-cooled nuclear Reactor (SCWRs) designs cannot be optimized without such data. A set of experimental data obtained in Freon-12 (modeling fluid) cooled vertical bare bundle at the Institute of Physics and Power Engineering (IPPE, Obninsk, Russia) was analyzed. The existence of three distinct regimes for forced convention with supercritical fluids was experienced. (1) Normal heat transfer; (2) Deteriorated heat transfer, characterized by higher than expected temperatures; and (3) Enhanced heat transfer, characterized by lower than expected temperatures. This work compares the heat transfer coefficient of the experiments to predictions based upon current correlations for heat transfer in super critical fluids where the 1-D correlations are based upon tube data under supercritical water conditions. (author)

  15. Antimicrobial Peptides in Toroidal and Cylindrical Pores

    OpenAIRE

    Mihajlovic, Maja; Lazaridis, Themis

    2010-01-01

    Antimicrobial peptides (AMPs) are small, usually cationic peptides, which permeabilize biological membranes. Their mechanism of action is still not well understood. Here we investigate the preference of alamethicin and melittin for pores of different shapes, using molecular dynamics (MD) simulations of the peptides in pre-formed toroidal and cylindrical pores. When an alamethicin hexamer is initially embedded in a cylindrical pore, at the end of the simulation the pore remains cylindrical or ...

  16. Cylindrical Superlens by a Coordinate Transformation

    OpenAIRE

    Yan, Min; Yan, Wei; Qiu, Min

    2008-01-01

    Cylinder-shaped perfect lens deduced from the coordinate transformation method is proposed. The previously reported perfect slab lens is noticed to be a limiting form of the cylindrical lens when the inner radius approaches infinity with respect to the lens thickness. Connaturality between a cylindrical lens and a slab lens is affirmed by comparing their eigenfield transfer functions. We numerically confirm the subwavelength focusing capability of such a cylindrical lens with consideration of...

  17. Computing Cylindrical Algebraic Decomposition via Triangular Decomposition

    OpenAIRE

    Chen, Changbo; Maza, Marc Moreno; Xia, Bican; Yang, Lu

    2009-01-01

    Cylindrical algebraic decomposition is one of the most important tools for computing with semi-algebraic sets, while triangular decomposition is among the most important approaches for manipulating constructible sets. In this paper, for an arbitrary finite set $F \\subset {\\R}[y_1, ..., y_n]$ we apply comprehensive triangular decomposition in order to obtain an $F$-invariant cylindrical decomposition of the $n$-dimensional complex space, from which we extract an $F$-invariant cylindrical algeb...

  18. Propagation Mechanism of Cylindrical Cellular Detonation

    Science.gov (United States)

    Han, Wen-Hu; Wang, Cheng; Ning, Jian-Guo

    2012-10-01

    We investigate the evolution of cylindrical cellular detonation with different instabilities. The numerical results show that with decreasing initial temperature, detonation becomes more unstable and the cells of the cylindrical detonation tend to be irregular. For stable detonation, a divergence of cylindrical detonation cells is formed eventually due to detonation instability resulting from a curved detonation front. For mildly unstable detonation, local overdriven detonation occurs. The detonation cell diverges and its size decreases. For highly unstable detonation, locally driven detonation is more obvious and the front is highly wrinkled. As a result, the diverging cylindrical detonation cell becomes highly irregular.

  19. Radar reflectivity of bare and vegetation-covered soil

    Science.gov (United States)

    Ulaby, F. T.; Dobson, M. C.; Bradley, G. A.

    1981-01-01

    Radar sensitivity to soil moisture content has been investigated experimentally for bare and vegetation-covered soil using detailed spectral measurements obtained by a truck-mounted radar spectrometer in the 1-8 GHz band and by airborne scatterometer observations at 1.6, 4.75, and 13.3 GHz. It is shown that radar can provide quantitative information on the soil moisture content of both bare and vegetation-covered soil. The observed soil moisture is in the form of the soil matric potential or a related quantity such as the percent of field capacity. The depth of the monitored layer varies from 1 cm for very wet soil to about 15 cm for very dry soil.

  20. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the chargedinterfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits shortrange in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  1. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    OpenAIRE

    kashmera ashish khedkkar safaya; Rekha Lathi

    2012-01-01

    This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS) camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  2. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    Directory of Open Access Journals (Sweden)

    kashmera ashish khedkkar safaya

    2012-05-01

    Full Text Available This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  3. The Political Animal: Species-Being and Bare Life

    Directory of Open Access Journals (Sweden)

    Laura Hudson

    2008-01-01

    Full Text Available Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  4. Photon emissivity of the electrosphere of bare strange stars

    OpenAIRE

    Harko, T.; Cheng, KS

    2005-01-01

    We consider the spectrum, emissivity, and flux of the electromagnetic radiation emitted by the thin electron layer (the electrosphere) at the surface of a bare strange star. In particular, we carefully consider the effect of the multiple and uncorrelated scattering on the radiation spectrum (the Landau-Pomeranchuk-Migdal effect), together with the effect of the strong electric field at the surface of the star. The presence of the electric field strongly influences the radiation spectrum emitt...

  5. Single ionization of diatomic molecules by bare ion impact

    International Nuclear Information System (INIS)

    The molecular three-Coulomb wave model (M3CW) has been extensively used to study the double-differential ionization cross sections (DDCS) of diatomic molecules by the impact of bare ions at intermediate and high energies. In this model, the distortion of the initial channel by the incoming projectile is also included. The present DDCS results are found to be in good accord both with the experiment of Baran et al 2008 as well as with other theory

  6. The Political Animal: Species-Being and Bare Life

    OpenAIRE

    Laura Hudson

    2008-01-01

    Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  7. Diffusion from cylindrical waste forms

    International Nuclear Information System (INIS)

    The diffusion of a single component material from a finite cylindrical waste form, initially containing a uniform concentration of the material, is investigated. Under the condition that the cylinder is maintained in a well-stirred bath, expressions for the fractional inventory leached and the leach rate are derived with allowance for the possible permanent immobilization of the diffusant through its decay to a stable product and/or its irreversible reaction with the waste form matrix. The usefulness of the reported results in nuclear waste disposal applications is emphasized. The results reported herein are related to those previously derived at Oak Ridge National Laboratory by Bell and Nestor. A numerical scheme involving the partial decoupling of nested infinite summations and the use of rapidly converging rational approximants is recommended for the efficient implementation of the expressions derived to obtain reliable estimates of the bulk diffusion constant and the rate constant describing the diffusant-waste form interaction from laboratory data

  8. Observations of ion-acoustic cylindrical solitons

    Science.gov (United States)

    Hershkowitz, N.; Romesser, T.

    1974-01-01

    Experimental observations of cylindrical solitons in a collisionless plasma are presented. The data obtained show that cylindrical solitonlike objects exist and that their properties are consistent with those of one- and three-dimensional solitons. It is found that compressive density perturbations evolve into solitons. The number of the solitons is determined by the width and amplitude of the applied pulse.

  9. Magnetic guns with cylindrical permanent magnets

    DEFF Research Database (Denmark)

    Vokoun, David; Beleggia, Marco; Heller, Luděk

    2012-01-01

    The motion of a cylindrical permanent magnet (projectile) inside a tubular permanent magnet, with both magnets magnetized axially, illustrates nicely the physical principles behind the operation of magnetic guns. The force acting upon the projectile is expressed semi-analytically as derivative of...... the generated forces and motion of the inner cylindrical magnet....

  10. Performance analysis of cylindrical metal hydride beds with various heat exchange options

    International Nuclear Information System (INIS)

    Highlights: • 3D numerical model for the comparison of H2 uptake performances in MH reactors. • 4 options of heat exchange between heat transfer fluid and MH in cylindrical reactor compared. • Straight tube internal heat exchanger. • Helical coil internal heat exchanger. • External heat exchange without and with transversal fins in the MH reactor. - Abstract: A 3D numerical heat-and-mass transfer model was used for the comparison of H2 uptake performances of powdered cylindrical MH beds comprising MmNi4.6Al0.4 hydrogen storage material. The considered options of heat exchange between the MH and a heat transfer fluid included internal cooling using straight (I) or helically coiled (II) tubing, as well as external cooling of the MH bed without (III) and with (IV) transversal fins. The dynamic performances of these layouts were compared based on the numerical simulation. The effect of heat transfer coefficient was also analysed

  11. Nuclear Reactor RA Safety Report, Vol. 4, Reactor

    International Nuclear Information System (INIS)

    RA research reactor is thermal heavy water moderated and cooled reactor. Metal uranium 2% enriched fuel elements were used at the beginning of its operation. Since 1976, 80% enriched uranium oxide dispersed in aluminium fuel elements were gradually introduced into the core and are the only ones presently used. Reactor core is cylindrical, having diameter 40 cm and 123 cm high. Reaktor core is made up of 82 fuel elements in aluminium channels, lattice is square, lattice pitch 13 cm. Reactor vessel is cylindrical made of 8 mm thick aluminium, inside diameter 140 cm and 5.5 m high surrounded with neutron reflector and biological shield. There is no containment, the reactor building is playing the shielding role. Three pumps enable circulation of heavy water in the primary cooling circuit. Degradation of heavy water is prevented by helium cover gas. Control rods with cadmium regulate the reactor operation. There are eleven absorption rods, seven are used for long term reactivity compensation, two for automatic power regulation and two for safety shutdown. Total anti reactivity of the rods amounts to 24%. RA reactor is equipped with a number of experimental channels, 45 vertical (9 in the core), 34 in the graphite reflector and two in the water biological shield; and six horizontal channels regularly distributed in the core. This volume include detailed description of systems and components of the RA reactor, reactor core parameters, thermal hydraulics of the core, fuel elements, fuel elements handling equipment, fuel management, and experimental devices

  12. Plenum separator system for pool-type nuclear reactors

    International Nuclear Information System (INIS)

    A pool-type liquid-metal-heat-transfer nuclear reactor is described which consists of: a vertically disposed generally cylindrical reactor vessel having a closed bottom portion, and a closure head atop the reactor vessel and closing the reactor vessel; the reactor vessel enclosing the major components of the nuclear reactor which include a reactor core supported at a centrally disposed lower portion of the reactor vessel; a bottom-supported gas-plenum-forming hollow cylindrical member closed at its upper end, the hollow cylindrical member sealed to and supported by the reactor vessel; a hollow cylindrically conformed neutron shield member spaced from and radially surrounding the reactor core; separate liquid-metal plena confining liquid metal during normal reactor operation and comprising a hot upper plenum, a cold lower plenum and intermediate temperature plena; the liquid metal intakes of the liquid metal pumps positioned in the cold lower plenum with the cooler liquid metal therein being pumped upwardly through the reactor core to be heated and exit therefrom in a turbulent fashion; and the liquid metal intakes of the heat exchangers positioned within the hot upper plenum and the liquid metal discharges of the heat exchangers positioned within the cold lower plenum to discharge cooled liquid metal into the cold lower plenum

  13. Thermomechanical and isothermal fatigue behavior of bare and coated superalloys

    International Nuclear Information System (INIS)

    Thermomechanical fatigue (TMF) and isothermal fatigue (IF) experiments were performed on bare Mar-M246 as well as bare and coated Mar-M247 nickel based superalloys at strain ranges from 0.335 to 1 percent. The experiments were conducted in air, through a temperature range of 500 to 1,038 C at a constant strain rate of 5.0 x 10-5 s-1. Due to the coarse-grained structure of Mar-M246, TMF lives scattered considerably under low strain range conditions. Electron microscopy studies show that significant surface oxidation and gamma prime, γ', depleted zones occur for Mar-M246 under these conditions. In the surface grain, where the change in γ' morphology is most pronounced, γ' rafted along axes ∼±45 deg from the loading axis. The influence of a protective coating on the IF and TMF lives of Mar-M247 was also examined. Results indicate that the coating does not significantly affect the fatigue lives of Mar-M247. The oxidation behavior of bare and coating Mar-M247 was investigated via X-ray microprobe and Auger Spectroscopy. Through these analyses, it is evident that the coating was completely degraded when exposed to the test environment for a long time. In both Mar-M246 and Mar-M247, in-phase thermomechanical fatigue (TMF IP) loading resulted in intergranular cracking. TMF IP loading promoted multiple cracks at the coating/substrate interface of coating Mar-M247. Finally, Eshelby techniques were used to calculate stress distributions in the vicinity of a surface oxide and second-phase particle at the coating/substrate interface

  14. Wave energy resource in the Estaca de Bares area (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, G.; Carballo, R. [Univ. of Santiago de Compostela, EPS, Hydraulic Eng., Campus Univ. s/n, 27002 Lugo (Spain)

    2010-07-15

    The area around Cape Estaca de Bares (the northernmost point of Iberia) presents a great potential for wave energy exploitation owing to its prominent position, with average deepwater wave power values exceeding 40 kW/m. The newly available SIMAR-44 dataset, composed of hindcast data spanning 44 years (1958-2001), is used alongside wave buoy data and numerical modelling to assess this substantial energy resource in detail. Most of the energy is provided by waves from the IV quadrant, generated by the prevailing westerlies blowing over the long Atlantic fetch. Combined scatter and energy diagrams are used to characterise the wave energy available in an average year in terms of the sea states involved. The lion's share is shown to correspond to significant wave heights between 2 and 5 m and energy periods between 11 and 14 s. The nearshore energy patterns are then examined using a coastal wave model (SWAN) with reference to four situations: average wave energy, growing wave energy (at the approach of a storm), extreme wave energy (at the peak of the storm) and decaying wave energy (as the storm recedes). The irregular bathymetry is found to produce local concentrations of wave energy in the nearshore between Cape Prior and Cape Ortegal and in front of Cape Estaca de Bares, with similar patterns (but varying wave power) in the four cases. These nearshore areas of enhanced wave energy are of the highest interest as prospective sites for a wave energy operation. The largest of them is directly in the lee of a large underwater mount west of Cape Ortegal. In sum, the Estaca de Bares area emerges as one of the most promising for wave energy exploitation in Europe. (author)

  15. Swift monitoring of the "bare" AGN Ark120

    Science.gov (United States)

    Gliozzi, Mario

    2016-01-01

    We present the first results from our monitoring campaign of the prototypical bare AGN Ark 120 observed with the Swift UVOT and XRT. A simultaneous study of UV, optical, and X-ray variability in AGN is one of the most effective tools to shed light on their central engine. Ark 120 appears to be highly variable at all wavelengths and over all the timescales probed during the Swift campaign, with a higher degree of variability in the higher energy bands. The temporal variations are accompanied by spectral changes, which may provide crucial information on the origin of variability and the interplay between disk and corona in AGN.

  16. FBR and RBR particle bed space reactors

    International Nuclear Information System (INIS)

    Compact, high-performance nuclear reactor designs based on High-Temperature Gas Reactors (HTGRs) particulate fuel are investigated. The large surface area available with the small-diameter (approx. 500 microns) particulate fuel allows very high power densities (MW's/liter), small temperature differences between fuel and coolant (approx. 100K), high coolant-outlet temperatures (1500 to 30000K, depending on design), and fast reactor startup (approx. 2 to 3 seconds). Two reactor concepts are developed - the Fixed Bed Reactor (FBR), where the fuel particles are packed into a thin annular bed between two porous cylindrical drums, and the Rotating Bed Reactor (RBR), where the fuel particles are held inside a cold rotating (typically approx. 500 rpm) porous cylindrical drum. The FBR can operate steady-state in the closed-cycle He-cooled mode or in the open-cycle H2-cooled mode. The RBR will operate only in the open-cycle H2-cooled mode

  17. Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John

    1964-01-01

    This pamphlet describes how reactors work; discusses reactor design; describes research, teaching, and materials testing reactors; production reactors; reactors for electric power generation; reactors for supply heat; reactors for propulsion; reactors for space; reactor safety; and reactors of tomorrow. The appendix discusses characteristics of U.S. civilian power reactor concepts and lists some of the U.S. reactor power projects, with location, type, capacity, owner, and startup date.

  18. Life-cycle cost implications of a system using bare SNF transfer

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) is planning the use of the Multi-Purpose Canister (MPC) to handle transportation, storage, and disposal of civilian spent nuclear fuel. This canister, which would be loaded and sealed at the utility site, would remain sealed through waste emplacement in a Mined Geologic Disposal System (MGDS). Two sizes of MPCs are now being considered: large and small rail. The large rail canister has design requirements to be compatible with a 125 ton hook weight crane when fully loaded in the pool with fuel assemblies, water, transportation overpack, and the lifting yoke. The small rail canister under the same conditions weighs less than 75 tons. At present, it is estimated that between four and seventeen reactors will not be able to accommodate either canister. One method of accommodating MPCs at all reactors is the use of Bare Spent nuclear fuel Transfer (BST). In this concept, a small transfer cask is used to move small numbers of assemblies from the spent fuel pool to an external transfer station where a large MPC is loaded. After several of these transfers, the MPC is sealed and either stored on-site, transported to a central storage site, or transported to the MGDS. This paper addresses the total system cost implications of use of BST at 20 sites (31 reactors) which are currently projected to be unable to use the large rail MPC. Results are presented parametrically as a function of the BST capital cost and the time required to load a MPC. This analysis indicates use of BST may be economically favorable if the combination of MPC load times and capital expenditures can be kept to a reasonable level

  19. Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

    Energy Technology Data Exchange (ETDEWEB)

    Mahnken, Andreas H., E-mail: mahnken@med.uni-marburg.de [University Hospital Giessen and Marburg, Philipps University of Marburg, Department of Diagnostic Radiology (Germany); Hoffman, Andras; Autschbach, Ruediger; Damberg, Anneke L. M., E-mail: anneke.damberg@rwth-aachen.de [University Hospital RWTH Aachen, Department of Thoracic, Cardiac and Vascular Surgery (Germany)

    2013-08-01

    BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach. A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.

  20. Cylindrical-shaped nanotube field effect transistor

    KAUST Repository

    Hussain, Muhammad Mustafa

    2015-12-29

    A cylindrical-shaped nanotube FET may be manufactured on silicon (Si) substrates as a ring etched into a gate stack and filled with semiconductor material. An inner gate electrode couples to a region of the gate stack inside the inner circumference of the ring. An outer gate electrode couples to a region of the gate stack outside the outer circumference of the ring. The multi-gate cylindrical-shaped nanotube FET operates in volume inversion for ring widths below 15 nanometers. The cylindrical-shaped nanotube FET demonstrates better short channel effect (SCE) mitigation and higher performance (I.sub.on/I.sub.off) than conventional transistor devices. The cylindrical-shaped nanotube FET may also be manufactured with higher yields and cheaper costs than conventional transistors.

  1. Multimode interaction in axially excited cylindrical shells

    OpenAIRE

    Silva F. M. A.; Rodrigues L.; Gonçalves P. B.; Del Prado Z. J. G. N

    2014-01-01

    Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural fr...

  2. Cylindrical contact homology and topological entropy

    OpenAIRE

    Alves, Marcelo R. R.

    2014-01-01

    We establish a relation between the growth of the cylindrical contact homology of a contact manifold and the topological entropy of Reeb flows on this manifold. We show that if a contact manifold $(M,\\xi)$ admits a hypertight contact form $\\lambda_0$ for which the cylindrical contact homology has exponential homotopical growth rate, then the Reeb flow of every contact form on $(M,\\xi)$ has positive topological entropy. Using this result, we provide numerous new examples of contact 3-manifolds...

  3. Cylindrical microemulsions: a polymer-like phase ?

    OpenAIRE

    Safran, S. A.; Turkevich, L.A.; Pincus, P

    1984-01-01

    The regions of stability of spherical, cylindrical, and lamellar phases of microemulsions are calculated within mean-field theory. In the cylindrical phase, thermal fluctuations determine a temperature dependent persistence length below which the cylinders are rigid (rod-like) and above which the cylinders are flexible (polymer-like). The length of the polymer-like chains depends on concentration and temperature. The radii of gyration of these flexible microemulsions are also calculated.

  4. Cylindrical Helix Spline Approximation of Spatial Curves

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, we present a new method for approximating spatial curves with a G1 cylindrical helix spline within a prescribed tolerance. We deduce the general formulation of a cylindrical helix,which has 11 freedoms. This means that it needs 11 restrictions to determine a cylindrical helix. Given a spatial parametric curve segment, including the start point and the end point of this segment, the tangent and the principal normal of the start point, we can always find a cylindrical segment to interpolate the given direction and position vectors. In order to approximate the known parametric curve within the prescribed tolerance, we adopt the trial method step by step. First, we must ensure the helix segment to interpolate the given two end points and match the principal normal and tangent of the start point, and then, we can keep the deviation between the cylindrical helix segment and the known curve segment within the prescribed tolerance everywhere. After the first segment had been formed, we can construct the next segment. Circularly, we can construct the G1 cylindrical helix spline to approximate the whole spatial parametric curve within the prescribed tolerance. Several examples are also given to show the efficiency of this method.

  5. Fast liner proposal. [Magnetic implosions of cylindrical liners

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, A.R.; Freeman, B.L.; Gerwin, R.A.; Jarboe, T.R.; Krakowski, R.A.; Malone, R.C.; Marshall, J.; Miller, R.L.; Suydam, B.

    1977-08-01

    This is a proposal to study, both theoretically and experimentally, the possibility of making a fusion reactor by magnetically imploding a cylindrical metallic shell on a prepared plasma. The approach is characterized by the following features: (1) the nonrotating liner would be driven by an axial current, (2) the plasma would also carry an axial current that provides an azimuthal magnetic field for thermal insulation in both the radial and longitudinal directions, (3) solid end plugs would be utilized to prevent axial loss of particles, and (4) liner speeds would be in the 10/sup 6/ cm/s range. The preliminary calculations indicate (1) that the energetics are favorable (energy inputs of about 10 MJ might produce a machine in the break-even regime), (2) that radiation and heat losses could be made tolerable, (3) that alpha-particle heating could be made very effective, and (4) that Taylor instabilities in a fast liner might be harmless because of the large viscosities at high pressures. A preliminary conceptual design of the sort of fusion reactor that might result from such an approach is discussed, as are some of the relevant reactor scaling arguments.

  6. Natural frequency of a circular cylindrical shell filled with fluid

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyeong Hoon; Kim, Tae Wan; Kim, Kang Soo; Park, Keun Bae [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-08-01

    This report presents an analytical method for evaluating the free vibration of a circular cylindrical shell filled with bounded compressible fluid. The analytical method was developed by means of the finite Fourier series expansion method. The compressible fluid motion was determined by means of the linear velocity potential theory. To clarify the validity of the analytical method, the natural frequencies of a circular cylindrical shell with the clamped-clamped boundary condition, and filled with water, were obtained by the analytical method and the finite element method using a commercial ANSYS 5.2 software. Excellent agreement on the natural frequencies of the fluid-filled shell structure was found. The compressibility and density of fluid effects the normalized coupled natural frequencies were investigated. The density of fluid affects on all coupled natural frequencies of the shell,, whereas the compressibility and bounding of fluid affects mainly on the natural frequencies of lower circumferential modes. The theory developed in this report will be applicable to the dynamic analysis of a core support barrel in SMART integral reactor filled with coolant. (author). 15 refs., 14 figs., 1 tab.

  7. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  8. Regular step distribution of the bare Si(553) surface

    Science.gov (United States)

    Kopciuszyński, M.; Dyniec, P.; Zdyb, R.; Jałochowski, M.

    2015-06-01

    Vicinal Si(111) surfaces are known to undergo faceting when the temperature is lowered below the (1 ×1 ) to (7 ×7 ) phase transition temperature. Depending on the cutoff angle value and direction with respect to the crystallographic axis, various facets, together with low Miller index terraces, are formed. Here, we report the formation of regularly distributed steps over macroscopic sample regions of the bare Si(553) surface. The surface morphology is studied with scanning tunneling microscopy and reflection high energy electron diffraction techniques. The (111) terraces of 2.88 nm in width, which are separated by double atomic height steps, reveal an unusual reconstruction. However, the electronic structure determined with angle resolved photoemission spectroscopy shows bands very similar to those observed for the Si (111 )-(7 ×7 ) surface.

  9. Interaction of Hg Atom with Bare Si(111) Surface

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Jun; LIU Ying

    2006-01-01

    To evaluate the interaction between Hg atom and bare Si(111) surface, three types of silicon cluster models of Si4H7, Si7H10 and Si16H20 together with their Hg complexes were studied by using hybrid (U)B3LYP density functional theory method. Optimized geometries and energies for Hg atom on different adsorption sites indicate that: 1) the binding energies at different adsorption sites are small (ranging from ~3 to 8 kJ/mol dependent on the adsorption sites), suggesting a weak interaction between Hg atom and silicon surface; 2) the most favorable adsorption site is the on top (T) site. By analyzing their natural bonding orbitals, the possible reason of this difference is suggested.

  10. Voltammetry of nitrobenzene at bare and DODAC coated Pt

    International Nuclear Information System (INIS)

    The reductive electrochemistry of nitrobenzene at one concentration was examined 1:1 water-propanol mixture at bare and DODAC covered platinum semi-micro electrodes using cyclic voltammetry. Generally it is believed [1-9] that couple of reduction and oxidation peak is associated with four electron transfer process which leads to the formation of phenylhydroxylamine in neutral and alkaline solutions. During electroreduction of nitrobenzene at a certain concentration, anodic shift is observed (108 mV) on DODAC covered platinum electrode. It reveals that in the presence of cationic micelles [10-18] partition of nitrobenzene occurs where nitrobenzene is more concentrated in micellar phase than in bulk. Cathodic and anodic peak currents show almost linear trend with increasing potential sweep rate. Similar trend is observed for cathodic and anodic peak potentials, respectively. (author)

  11. Effect of vertical seismic load on shear-bending buckling strength of thin cylindrical shells

    International Nuclear Information System (INIS)

    The main vessels of Fast Breeder Reactors (FBR) are cylindrical structures containing liquid, and have to be thin-walled in order to withstand severe thermal condition. One of the most critical factors in the design of earthquake-resistant FBRs is the buckling strength of the cylinder part of the reactor vessel. In order to investigate various non-linear response characteristics, including buckling, of thin cylindrical shells under vertical and horizontal seismic motion, pseudo-dynamic experiments and non-linear response simulation analysis is performed. It is confirmed that buckling is caused mainly by horizontal seismic loads, and that vertical seismic loads reduce the lateral load-carrying capacity of cylinders and amplify response displacement for a given horizontal seismic load. To evaluate the amplification of non-linear horizontal responses due to vertical input motions, the authors define a response amplification factor, which is calculated from floor response spectra of seismic waves

  12. Diurnal emissivity dynamics in bare versus biocrusted sand dunes.

    Science.gov (United States)

    Rozenstein, Offer; Agam, Nurit; Serio, Carmine; Masiello, Guido; Venafra, Sara; Achal, Stephen; Puckrin, Eldon; Karnieli, Arnon

    2015-02-15

    Land surface emissivity (LSE) in the thermal infrared depends mainly on the ground cover and on changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 μm channel. This phenomenon is attributed to water vapor adsorption by the sand/biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spatial impact. As biocrusts cover vast regions in deserts worldwide, this discovery has repercussions for LSE estimations in deserts around the globe, and these LSE variations can potentially have considerable effects on geophysical models from local to regional scales. PMID:25437760

  13. Free vibrations of finite circular cylindrical shells and tubes with and without a surrounding fluid

    International Nuclear Information System (INIS)

    Numerical models are evaluated for determining the natural frequencies of thin-walled closed circular cylindrical shells and straight tube bundles in a fluid or without a fluid. Experiments are described to check the reliability of the numerical models. Some of the models are applied for the vibration analysis of some parts of the sodium-steam heat exchangers of the SNR-300 reactor in Kalkar (West Germany). (Auth.)

  14. Design guide for calculating hydrodynamic mass. Part I. Circular cylindrical structures

    International Nuclear Information System (INIS)

    Many reactor and plant components contain, or are submerged in, a fluid. The fluid moving with a vibrating structure has an important effect on the dynamics of the structure, particularly on its natural frequencies. The effect of the fluid on natural frequencies can be accounted for using the hydrodynamic mass associated with the structure. The design guide provides formulas, graphs, and computer programs for calculating hydrodynamic masses of circular cylindrical structures

  15. Stress of anisotropic structure vaults consisting of cylindrical shells. Part I

    International Nuclear Information System (INIS)

    A method is described for the numerical solution of problems based on analytical relations derived for bending deformation of a cylindrical shell stressed with radially flat, rotationally asymmetrical loads. The relations are expressed and processed by a matrix representation suitable for cascade-type calculation with free parameters and for computer processing. The method thus permits the designing of vaults of arbitrary eccentricities and variable thicknesses. A vault of this particular type is fairly common in nuclear reactor constructions. (M.S.)

  16. Fast breeder reactor

    International Nuclear Information System (INIS)

    The fluid-cooled fast breeder reactor described includes an outer cylindrical boundary wall, a plurality of canless fuel elements and breeder material elements received within the boundary wall and being in an array therein forming a fissionable fuel zone and a breeder material zone coaxially surrounding the fissionable fuel zone, a coolant supply system for applying fluid coolant at uniform pressure to the entire cross section within the cylindrical boundary wall, and flow guide devices extending substantially horizontally and disposed at different levels one above the other within the breeder material zone which coaxially surrounds the fissionable fuel zone, means for elastically securing the flow guide devices at alternate levels within the breeder material to the boundary wall, the flow guide devices at the levels intermediate the alternate levels being spaced by an annular gap from the boundary wall. 7 claims, 7 drawing figures

  17. Thermal-hydraulic analysis of a cylindrical blanket module using ATHENA code

    International Nuclear Information System (INIS)

    ATHENA (Advanced Thermal-Hydraulic Energy Network Analyzer) is a new computer code for thermal-hydraulic analyses of many energy systems. Multiple-loop and multiple-fluid capabilities have been emphasized during the code development. A pilot version of ATHENA has incorporated a fusion kinetic package to model the effect of first wall temperature variation on the reactor conditions. The capability has been demonstrated by analyzing the performance under various conditions of a cylindrical fusion blanket module. The results have shown the viability of using ATHENA for fusion reactor design and safety analyses

  18. The Dizzying Depths of the Cylindrical Mirror

    Science.gov (United States)

    DeWeerd, Alan J.; Hill, S. Eric

    2005-02-01

    A typical introduction to geometrical optics treats plane and spherical mirrors. At first glance, it may be surprising that texts seldom mention the cylindrical mirror, except for the occasional reference to use in fun houses and to viewing anamorphic art.1,2 However, even a cursory treatment reveals its complexity. Holzberlein used an extended object to qualitatively illustrate that images are produced both before and behind a concave cylindrical mirror.3 He also speculated on how this extreme astigmatism results in an observer's dizziness. By considering a simple point object, we make a more detailed analysis of the cylindrical mirror and the dizziness it induces. First, we illustrate how rays from a point object reflect to form not one point image but two line images. Next, we describe how an observer perceives a likeness of the object. Finally, we suggest how confusing depth cues induce dizziness. Although we focus on the concave cylindrical mirror, the discussion is easy to generalize to the convex cylindrical mirror.

  19. Results from NNWSI [Nevada Nuclear Waste Storage Investigations] Series 2 bare fuel dissolution tests

    International Nuclear Information System (INIS)

    The dissolution and radionuclide release behavior of spent fuel in groundwater is being studied by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Two bare spent fuel specimens plus the empty cladding hulls were tested in NNWSI J-13 well water in unsealed fused silica vessels under ambient hot cell air conditions (25 degree C) in the currently reported tests. One of the specimens was prepared from a rod irradiated in the H. B. Robinson Unit 2 reactor and the other from a rod irradiated in the Turkey Point Unit 3 reactor. Results indicate that most radionuclides of interest fall into three groups for release modeling. The first group principally includes the actinides (U, Np, Pu, Am, and Cm), all of which reached solubility-limited concentrations that were orders of magnitude below those necessary to meet the NRC 10 CFR 60.113 release limits for any realistic water flux predicted for the Yucca Mountain repository site. The second group is nuclides of soluble elements such as Cs, Tc, and I, for which release rates do not appear to be solubility-limited and may depend on the dissolution rate of fuel. In later test cycles, 137Cs, 90Sr, 99Tc, and 129I were continuously released at rates between about 5 x 10-5 and 1 x 10-4 of inventory per year. The third group is radionuclides that may be transported in the vapor phase, of which 14C is of primary concern. Detailed test results are presented and discussed. 17 refs., 15 figs., 21 tabs

  20. Sensitivity analysis of CFD code FLUENT-12 for supercritical water in vertical bare tubes

    International Nuclear Information System (INIS)

    The ability to use FLUENT 12 or other CFD software to accurately model supercritical water flow through various geometries in diabatic conditions is integral to research involving coal-fired power plants as well as Supercritical Water-cooled Reactors (SCWR). The cost and risk associated with constructing supercritical water test loops are far too great to use in a university setting. Previous work has shown that FLUENT 12, specifically realizable k-ε model, can reasonably predict the bulk and wall temperature distributions of externally heated vertical bare tubes for cases with relatively low heat and mass fluxes. However, sizeable errors were observed for other cases, often those which involved large heat fluxes that produce deteriorated heat transfer (DHT) regimes. The goal of this research is to gain a more complete understanding of how FLUENT 12 models supercritical water cases and where errors can be expected to occur. One control case is selected where expected changes in bulk and wall temperatures occur and they match empirical correlations' predictions, and the operating parameters are varied individually to gauge their effect on FLUENT's solution. The model used is the realizable k-ε, and the parameters altered are inlet pressure, mass flux, heat flux, and inlet temperature. (author)

  1. Thermal analysis of cylindrical natural-gas steam reformer for 5 kW PEMFC

    Science.gov (United States)

    Jo, Taehyun; Han, Junhee; Koo, Bonchan; Lee, Dohyung

    2016-01-01

    The thermal characteristics of a natural-gas based cylindrical steam reformer coupled with a combustor are investigated for the use with a 5 kW polymer electrolyte membrane fuel cell. A reactor unit equipped with nickel-based catalysts was designed to activate the steam reforming reaction without the inclusion of high-temperature shift and low-temperature shift processes. Reactor temperature distribution and its overall thermal efficiency depend on various inlet conditions such as the equivalence ratio, the steam to carbon ratio (SCR), and the fuel distribution ratio (FDR) into the reactor and the combustor components. These experiments attempted to analyze the reformer's thermal and chemical properties through quantitative evaluation of product composition and heat exchange between the combustor and the reactor. FDR is critical factor in determining the overall performance as unbalanced fuel injection into the reactor and the combustor deteriorates overall thermal efficiency. Local temperature distribution also influences greatly on the fuel conversion rate and thermal efficiency. For the experiments, the operation conditions were set as SCR was in range of 2.5-4.0 and FDR was in 0.4-0.7 along with equivalence ratio of 0.9-1.1; optimum results were observed for FDR of 0.63 and SCR of 3.0 in the cylindrical steam reformer.

  2. Electronic Quantum Confinement in Cylindrical Potential Well

    CERN Document Server

    Baltenkov, A S

    2016-01-01

    The effects of quantum confinement on the momentum distribution of electrons confined within a cylindrical potential well have been analyzed. The motivation is to understand specific features of the momentum distribution of electrons when the electron behavior is completely controlled by the parameters of a non-isotropic potential cavity. It is shown that studying the solutions of the wave equation for an electron confined in a cylindrical potential well offers the possibility to analyze the confinement behavior of an electron executing one- or two-dimensional motion in the three-dimensional space within the framework of the same mathematical model. Some low-lying electronic states with different symmetries have been considered and the corresponding wave functions have been calculated; the behavior of their nodes and their peak positions with respect to the parameters of the cylindrical well has been analyzed. Additionally, the momentum distributions of electrons in these states have been calculated. The limi...

  3. Moon base reactor system

    Science.gov (United States)

    Chavez, H.; Flores, J.; Nguyen, M.; Carsen, K.

    1989-01-01

    The objective of our reactor design is to supply a lunar-based research facility with 20 MW(e). The fundamental layout of this lunar-based system includes the reactor, power conversion devices, and a radiator. The additional aim of this reactor is a longevity of 12 to 15 years. The reactor is a liquid metal fast breeder that has a breeding ratio very close to 1.0. The geometry of the core is cylindrical. The metallic fuel rods are of beryllium oxide enriched with varying degrees of uranium, with a beryllium core reflector. The liquid metal coolant chosen was natural lithium. After the liquid metal coolant leaves the reactor, it goes directly into the power conversion devices. The power conversion devices are Stirling engines. The heated coolant acts as a hot reservoir to the device. It then enters the radiator to be cooled and reenters the Stirling engine acting as a cold reservoir. The engines' operating fluid is helium, a highly conductive gas. These Stirling engines are hermetically sealed. Although natural lithium produces a lower breeding ratio, it does have a larger temperature range than sodium. It is also corrosive to steel. This is why the container material must be carefully chosen. One option is to use an expensive alloy of cerbium and zirconium. The radiator must be made of a highly conductive material whose melting point temperature is not exceeded in the reactor and whose structural strength can withstand meteor showers.

  4. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  5. EAARL Topography - Vicksburg National Military Park 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed

  6. EAARL Coastal Topography-Chandeleur Islands, Louisiana, 2010: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Bonisteel-Cormier, Jamie M.; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Nagle, David B.; Vivekanandan, Saisudha; Yates, Xan; Klipp, Emily S.

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and submerged topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Chandeleur Islands, acquired March 3, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  7. EAARL Coastal Topography - Northeast Barrier Islands 2007: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  8. Micromagnetic simulations of cylindrical magnetic nanowires

    KAUST Repository

    Ivanov, Yurii P.

    2015-05-27

    This chapter reviews micromagnetic simulations of cylindrical magnetic nanowires and their ordered arrays. It starts with a description of the theoretical background of micromagnetism. The chapter discusses main magnetization reversal modes, domain wall types, and state diagrams in cylindrical nanowires of different types and sizes. The results of the hysteresis process in individual nanowires and nanowire arrays also are presented. Modeling results are compared with experimental ones. The chapter also discusses future trends in nanowire applications in relation to simulations, such as current-driven dynamics, spintronics, and spincaloritronics. The main micromagnetic programs are presented and discussed, together with the corresponding links.

  9. Airstream Deflection Across a Cylindrical Surface

    Directory of Open Access Journals (Sweden)

    Aydin Yolar

    2016-01-01

    Full Text Available A cylindrical airstream was blown across a cylindrical surface. The deflection angle, peak speed, and asymmetry of the airstream were measured while changing the location of the cylinder relative to the center of the wind column, and while changing the speed of the airstream. It was found that the closer the cylinder is to the center of the airstream, the greater the deflection angle, the lower the peak speed, and the greater the asymmetry of the deflected airstream. It was also found that the wind speed has no impact on the deflection angle when the cylinder remains in a fixed position.

  10. Research on cylindrical shell vibration reduction systems

    Institute of Scientific and Technical Information of China (English)

    XING Xiao-liang; WANG Min-qing

    2008-01-01

    Longitudinal and horizontal vibration must both be reduced in an effective vibration isolation system. We present a cylindrical shell vibration isolator as a dynamic system composed of four springs and dampers. Vibration is directly produced by the motion of machinery, and more is subsequently generated by harmonic frequencies within their structure. To test the effectiveness of our isolator, we first determined equations for the transmission of vibration from the machine to its cylindrical shell. Damping effects produced by the vibration parameters of our system are then analyzed.

  11. Enumeration of Cylindric Plane Partitions - part I

    CERN Document Server

    Langer, Robin

    2012-01-01

    Cylindric plane partitions may be thought of as a natural generalization of reverse plane partitions. A generating series for the enumeration of cylindric plane partitions was recently given by Borodin. The first result of this paper is a $(q,t)$-analog of Borodin's identity which extends previous work by Okada in the reverse plane partition case. Our proof uses commutation relations for $(q,t)$-vertex operators acting on Macdonald polynomials as given by Garsia, Haiman and Tesla. The second result of this paper is an explicit combinatorial interpreation of the $(q,t)$-Macdonald weight in terms of a non-intersecting lattice path model on the cylinder.

  12. RESONANCE RADIATION OF SUBMERGED INFINITE CYLINDRICAL SHELL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The resonance sound radiation from submerged infinite elastic cylindrical shell, excited by internal harmonic line force, is investigated. The shell radiation power is presented in terms of resonant modal radiation derived from resonance radiation theory (RRT). The resonance radiation formulae are derived from classical Rayleigh normal mode solution, which are useful for understanding the mechanism of sound radiation from submerged shells. As an example, numerical calculation of a thin steel cylindrical shell is done by using these two methods. It seems that the results of RRT solutions are in good agreement with that of Rayleigh normal mode solutions.

  13. Electron capture by bare ions on water molecules

    Science.gov (United States)

    Rivarola, Roberto; Montenegro, Pablo; Monti, Juan; Fojón, Omar

    2016-05-01

    Single electron capture from water molecules by impact of bare ions is theoretically investigated at intermediate and high collision energies. This reaction is of fundamental importance to determine the deposition of energy in biological matter irradiated with ion beams (hadrontherapy), dominating other ionizing processes of the target at low-intermediate impact velocities and giving principal contributions to the energetic region where electronic stopping power maximizes. The dynamics of the interaction between the aggregates is described within the one active-electron continuum distorted wave-eikonal initial state theory. The orbitals of the target in the ground state are represented using the approximate self-consistent complete neglect of differential orbitals (SC-CNDO) model. The contribution of different molecular orbitals on the partial cross sections to selected n-principal quantum number projectile states is discriminated as well as the collaboration of these n-states on total cross sections. The latter ones are dominated by capture to n=1 states at high enough energies decreasing their contribution as n increases.

  14. Nd-YAG laser welding of bare and galvanised steels

    International Nuclear Information System (INIS)

    Until recently, one of the problems that has held back the introduction of lasers into car body fabrication has been the difficulty of integrating the lasers with robots. Nd-YAG laser beams can be transmitted through fibre optics which, as well as being considerably easier to manipulate than a mirror system, can be mounted on more lightweight accurate robots. Although previously only available at low powers, recent developments in Nd-YAG laser technology mean that lasers of up to 1kW average power will soon be available, coupled to a fibre optic beam delivery system. The increasing usage of zinc coated steels in vehicle bodies has led to welding problems using conventional resistance welding as well as CO2 laser welding. The use of Nd-YAG lasers may be able to overcome these problems. This paper outlines work carried out at The Welding Institute on a prototype Lumonics 800W pulsed Nd-YAG laser to investigate its welding characteristics on bare and zinc coated car body steels

  15. Space Test of Bare-Wire Anode Tethers

    Science.gov (United States)

    Johnson, L.; Fujii, H. A.; Sanmartin, J. R.

    2007-01-01

    An international team, lead by Tokyo Metropolitan University, is developing a mission concept for a suborbital test of orbital-motion-limited (OML) bare-wire anode current collection for application to electrodynamic tether propulsion. The tether is a tape with a 50-mm width, 0.05-mm thickness, and 1-km length. This will be the first space test of the OML theory. In addition, by being an engineering demonstration (of space tethers), the mission will demonstrate electric beam generation for "sounding" determination of the neutral density profile in the ionospheric "E-layer." If selected by the Institute of Space and Astronautical Science/Japanese Aerospace Exploration Agency (JAXA), the mission will launch in early 2009 using an $520 Sounding Rocket. During ascent, and above =100 km in attitude, the 1-km tape tether will be deployed at a rate of 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow.This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using electrodynamic tethers for propulsion or power generation.

  16. AMQ Protocol Based Performance Analysis of Bare Metal Hypervisors

    Directory of Open Access Journals (Sweden)

    Dr Deepak Arora

    2014-06-01

    Full Text Available Cloud computing is one of the most exciting technology because of its cost-reducing approach, flexibility, and scalability. Hypervisor is the essential part of cloud technology; it is a component of software that provides a virtualized hardware environment to support running multiple operating systems concurrently using one physical server. In this paper we took KVM, XEN, Hyper-V and ESXi as hypervisors. We have compared the performance of Virtual Machines (VMs by RabbitMQ message broker server that uses Advanced Message Queuing Protocol(AMQP for breaking messages. We establish the setup on bare metal hypervisor that is installed directly on the hardware of the system. We took SAN (Shared Storage Network server for maintaining the storage of all VMs. By the evaluation of these hyperviosrs we got a brief idea about their performance on different parameters. These results will be beneficial to small enterprise, social group or any private IT firm which is choosing to build small cloud infrastructure with optimal benefits. Experiment results of checking the performance of VMs for all the hypervisors shows that there is performance variation on different applications and workloads of the hypervisors. None of the hypervisors outperform another at every aspect of our comparison.

  17. Water evaporation from bare soil at Paraiba, Brazil

    International Nuclear Information System (INIS)

    Measurements were accomplished in a 4,0 ha area in Centro de Ciencias Agrarias, UFPB, Areia City, Paraiba State, Brazil (6 deg C 58'S, 35 deg C 41'W and 645 m), aiming to determine water evaporation from bare soil, by energy and water balance approaches. Rain gauge, net radiometer, pyranometer and sensor for measuring the temperature and the relative humidity of the air and the speed of the wind, in two levels above the soil surface, were used to solve the energy balance equations. In the soil, two places were fitted with instruments, each one with two thermal probes, installed horizontally in the depths z1 = 2,0 cm and z2 = 8,0 cm, and a heat flux plate, for the measurement of the heat flux in the soil, the z1 = 5,0 cm. The measured data were stored every 30 minutes in a data logger. For the calculation of the water balance, three tensio-neutronics sites were installed, containing: an access tube for neutrons probe and eight tensiometers. The values of soil evaporation obtained by water balance were lower than obtained by energy balance because of the variability of the water balance terms. (author)

  18. Scattering from bare soils: C-band multipolarization scatterometer measurements

    Science.gov (United States)

    Casarano, Domenico; Buono, G.; Paparella, F.; Posa, Francesco; Sabatelli, Vincenzo

    1998-11-01

    Multi-angle, multi-polarization C-band backscattering measurements were performed over selected bare soil areas. To perform these measurements, an FM-CW radar has been designed and assembled. This device has the capability of resolving independent samples within the antenna footprint area, thus allowing range discrimination and improving the signal statistics. Two areas with different degrees of roughness and dielectric constants were selected and set up. Co-polarized backscattering coefficients were measured for incidence angles between 23 degrees and 60 degrees. To perform a model analysis of the backscattering properties, 'ground truth' data, including surface roughness profiles and soil moisture values (directly related to dielectric constant) were also collected. The 'classical' parameters, used to describe surface roughness, showed a wide spreading. This evidence and the data resulting from ground truth campaigns over many European test sites suggested an alternative description of surface roughness, based on the self-similarity (fractal) properties. The surfaces have therefore been described as fBm (Fractional Brownian Motion) processes, and their backscattering response has been theoretically modeled by a numerical simulation (in 3-D in order to also take into account anisotropy effects) in Kirchhoff approximation. The experimental data have been analyzed with both asymptotic models (IEM) considering a classical statistical description, and with the numerical simulation applied to fBm surfaces.

  19. Fortissimo: A Japanese Space Test Of Bare Wire Anode Tethers

    Science.gov (United States)

    Johnson, Les; Fujii, H. A.; Sanmartin, J. R.

    2008-01-01

    A Japanese led international team is developing a suborbital test of orbital-motion-limited (OML) bare wire anode current collection for application to electrodynamic tether (EDT) propulsion. The tether is a tape with a width of 25 mm, thickness of 0.05 mm, and is 300 m in length. This will be the first space test of OML theory. The mission will launch in the summer of 2009 using an S520 Sounding Rocket. During ascent, and above approx. 100 km in attitude, the tape tether will be deployed at a rate of approx. 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow. The total amount of current collected will be used to assess the validity of OML theory. This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using EDTs for propulsion or power generation.

  20. Geodesic Completeness of Orthogonally Transitive Cylindrical Spacetimes

    CERN Document Server

    Fernández-Jambrina, L

    1999-01-01

    In this paper a theorem is derived in order to provide a wide sufficient condition for an orthogonally transitive cylindrical spacetime to be singularity-free. The applicability of the theorem is tested on examples provided by the literature that are known to have regular curvature invariants.

  1. Optical methods for cylindrical rough surface testing

    Science.gov (United States)

    Perez Quintian, F.; Rebollo, Maria A.; Gaggioli, Nestor G.; Raffo, C. A.

    1999-07-01

    This work studies theoretically the scattering of light from cylindrical rough surfaces. It is shown, for the conical diffraction configuration, that the mean intensity on an observation plane perpendicular to the cylinder longitudinal axis, is related to the statistical parameters that characterize the surface: the roughness (sigma) and the correlation length T.

  2. Gravitational Binding Energy in Charged Cylindrical Symmetry

    CERN Document Server

    Sharif, M

    2014-01-01

    We consider static cylindrically symmetric charged gravitating object with perfect fluid and investigate the gravitational binding energy. It is found that only the localized part of the mass function provides the gravitational binding energy, whereas the non-localized part generated by the electric coupling does not contribute for such energy.

  3. Metastable magnetic domain walls in cylindrical nanowires

    International Nuclear Information System (INIS)

    The stability of the asymmetric domain wall (ATDW) in soft magnetic cylindrical nanowires and nanotubes is investigated using micromagnetic simulations. Our calculated phase diagram shows that for cylindrical permalloy nanowires, the transverse domain wall (TDW) is the ground state for radii below 20 nm whilst the Bloch point wall (BPW) is favoured in thicker wires. The ATDW stabilises only as a metastable state but with energy close to that of the BPW. Characterisation of the DW spin structures reveals that the ATDW has a vortex-like surface spin state, in contrast to the divergent surface spins of the TDW. This results in lowering of surface charge above the critical radius. For both cylindrical nanotubes and nanowires we find that ATDWs only appear to exist as metastable static states and are particularly suppressed in nanotubes due to an increase in magnetostatic energy. - Highlights: • We simulate the micromagnetic structures of domain walls in cylindrical nanowires. • A phase diagram identifies ground and metastable states. • Asymmetric transverse walls are metastable in nanowires but suppressed in tubes. • Unrolling surface magnetisation aids visualisation of asymmetry and chirality. • We predict experimental discrimination based on magnetic charge distribution

  4. Antibubbles and fine cylindrical sheets of air

    KAUST Repository

    Beilharz, D.

    2015-08-14

    Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air layers which can wrap around the entire drop to form repeatable antibubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread reaching all the way to the pinch-off nozzle. The air sheet can also wrap around this thread and remain stable over an extended period of time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these thin cylindrical air sheets is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer. We use interferometry to measure the air-layer thickness versus depth along the cylindrical air sheet and around the drop. The air film is thickest above the equator of the drop, but thinner below the drop and up along the air cylinder. Based on microbubble volumes, the thickness of the cylindrical air layer becomes less than 100 nm before it ruptures.

  5. Distributed neural signals on parabolic cylindrical shells

    Science.gov (United States)

    Hu, S. D.; Li, H.; Tzou, H. S.

    2013-06-01

    Parabolic cylindrical shells are commonly used as key components in communication antennas, space telescopes, solar collectors, etc. This study focuses on distributed modal neural sensing signals on a flexible simply-supported parabolic cylindrical shell panel. The parabolic cylindrical shell is fully laminated with a piezoelectric layer on its outer surface and the piezoelectric layer is segmented into infinitesimal elements (neurons) to investigate the microscopic distributed neural sensing signals. Since the dominant vibration component of the shell is usually the transverse oscillation, a new transverse mode shape function is defined. Two shell cases, i.e., the ratio of the meridian height to the half span distance of a parabola at 1:4 (shallow) and 1:1 (deep), are studied to reveal the curvature effect to the neural sensing signals. Studies suggest that the membrane signal component dominates for lower natural modes and the bending signal component dominates for higher natural modes. The meridional membrane and bending signal components are mostly concentrated on the high-curvature areas, while the longitudinal bending component is mostly concentrated on the relatively flat areas. The concentration behavior becomes more prominent as the parabolic cylindrical shell deepens, primarily resulting from the enhanced membrane effect due to the increased curvature.

  6. On isotropic cylindrically symmetric stellar models

    CERN Document Server

    Nolan, B C

    2004-01-01

    We attempt to match the most general cylindrically symmetric vacuum space-time with a Robertson-Walker interior. The matching conditions show that the interior must be dust filled and that the boundary must be comoving. Further, we show that the vacuum region must be polarized. Imposing the condition that there are no trapped cylinders on an initial time slice, we can apply a result of Thorne's and show that trapped cylinders never evolve. This results in a simplified line element which we prove to be incompatible with the dust interior. This result demonstrates the impossibility of the existence of an isotropic cylindrically symmetric star (or even a star which has a cylindrically symmetric portion). We investigate the problem from a different perspective by looking at the expansion scalars of invariant null geodesic congruences and, applying to the cylindrical case, the result that the product of the signs of the expansion scalars must be continuous across the boundary. The result may also be understood in ...

  7. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  8. Hydrolysis of Olive Oil with Immobilized Lipase in a Tapered Column Reactor

    Institute of Scientific and Technical Information of China (English)

    杨伯伦; 赵国胜; 林宏业

    2003-01-01

    Lipase was immobilized in ion exchange resin and then used in the hydrolysis of olive oil to produce fatty acids and glycerol. The time course of hydrolysis of olive oil was investigated in a stirred tank reactor using both of the free and immobilized lipases to find the yield of activity of immobilized enzyme. Continuous hydrolysis of olive oil was also carried out in a tapered column reactor and a cylindrical column reactor with a bottom ID of 10 mm at different upward flow rates. It can be known from experimental results that the degree of hydrolysis of olive oil in the tapered column reactor is moderately better than that in the cylindrical column reactor, the pressure drop in the tapered column reactor is much smaller than that in the cylindrical column reactor.

  9. Robot for reactor dismantling

    International Nuclear Information System (INIS)

    Purpose: To enable to attain the operation on a cylindrical coordinate system thereby performing dismantling operation exactly and at a high reliability. Constitution: A reactor dismantling robot is suspended by ropes by an elevating device to the inside of reactor shielding walls. The robot has a fixed portion having a plurality of legs abutting against the inner surface of the shieling walls while extending and shrinking radially in the horizontal direction and an arm portion having an operation arm disposed with a shielding wall breaking operation device. The arm portion is disposed with a mechanism for vertically moving the operation arm and a mechanism for forwarding and backwarding the operation arm in the horizontal direction and the arm portion itself is constituted so as to be rotatable around a vertical axis. (Seki, T.)

  10. Mounting impellors of nuclear reactor pumps

    International Nuclear Information System (INIS)

    A coolant pump for a liquid metal cooled nuclear reactor construction is described which has its impellor hub mounted on the drive shaft with an annular clearance. A drive coupling is effected by a plurality of cylindrical keys disposed parallel to the longitudinal axes of the hub and shaft and equally spaced in the clearance between them. (author)

  11. Borax accident in a nuclear reactor

    International Nuclear Information System (INIS)

    The basic equations of fluid mechanics were used to describe the propagation of a shock wave in the fluid. Using the linear theory of pertubation the pressure distributions were obtained and consequently stress and strain were determined in the wall of the cylindrical tank, and also the expansion of the vapour sphire generated at the explosions in the core of the reactor was obtained

  12. Field Investigations of Evaporation from a Bare Soil

    Science.gov (United States)

    Evett, Steven Roy

    Selected components of the water and energy balances at the surface of a bare clay loam were measured at 57 locations in a 1 ha field. Spatial and temporal variability of these components were also studied. Components included evaporation, irrigation, moisture storage, sensible heat flux and long wave radiation. Sub-studies were conducted on irrigation uniformity under low pressure sprinklers; and, on steel versus plastic microlysimeters (ML) of various lengths. An energy balance model of evaporation, requiring minimal inputs, was developed and validated giving an r ^2 value of 0.78. Model improvements included an easy method of accurately estimating soil surface temperature at many points in a field, and an empirically fitted transfer coefficient function for the sensible heat flux from the reference dry soil. The omission of soil heat flux and reflected shortwave radiation terms was shown to reduce model accuracy. Steel ML underestimated cumulative evaporation compared to plastic ML at 20 and 30 cm lengths. Cumulative evaporation increased with ML length. The 10 and 20 cm ML were too short for use over multiple days but 30 cm ML may not be long enough for extended periods. Daily net soil heat flux for steel ML averaged 44% higher than that for both plastic ML and undisturbed field soil. Christiansen's uniformity coefficient (UCC) was close to 0.83 for each of 3 irrigations when measured by both catch cans and by profile water contents. But UCC for the change in storage due to irrigation averaged only 0.43 indicating than the high uniformity of profile water contents was more due to surface and subsurface redistribution than to the uniformity of application. Profile water contents and catch can depths were time invariant across at least 3 irrigations. Midday soil surface temperatures and daily evaporation were somewhat less time invariant. Variogram plots for evaporation and surface temperature showed mostly random behavior. Relative variograms represented well

  13. Investigation of vibration of the heating cylindrical rod induced by boiling and condensation phenomena

    International Nuclear Information System (INIS)

    Flow induced vibrations (FIVs) are important and interesting phenomena from the view point of reactor safety. In nuclear power plants, fuel pins in reactor cores, heat exchange tubes in steam generators and some other complex structures can cause FIVs. Especially, in Boiling Water Reactor, subcooled or saturated boiling flows induce vibrations. These vibrations result in fretting wear of the structures and may cause a radioactive leakage. This paper deals with an experimental investigation of the cylindrical rod's vibrations induced from boiling an condensation phenomena on the circumferential surface of itself. The measurements were conducted changing the bulk water temperature from the saturation temperature at an atmospheric pressure to the degree of subcooling up to around 30 K. (author)

  14. Surface superconductivity in thin cylindrical Bi nanowire.

    Science.gov (United States)

    Tian, Mingliang; Wang, Jian; Ning, Wei; Mallouk, Thomas E; Chan, Moses H W

    2015-03-11

    The physical origin and the nature of superconductivity in nanostructured Bi remains puzzling. Here, we report transport measurements of individual cylindrical single-crystal Bi nanowires, 20 and 32 nm in diameter. In contrast to nonsuperconducting Bi nanoribbons with two flat surfaces, cylindrical Bi nanowires show superconductivity below 1.3 K. However, their superconducting critical magnetic fields decrease with their diameter, which is the opposite of the expected behavior for thin superconducting wires. Quasiperiodic oscillations of magnetoresistance were observed in perpendicular fields but were not seen in the parallel orientation. These results can be understood by a model of surface superconductivity with an enhanced surface-to-bulk volume in small diameter wires, where the superconductivity originates from the strained surface states of the nanowires due to the surface curvature-induced stress. PMID:25658139

  15. Determination of Coil Inductances Cylindrical Iron Nucleus

    Directory of Open Access Journals (Sweden)

    Azeddine Mazouz

    2014-03-01

    Full Text Available The paper describes the investigation and development of a structure and performance characteristics of a coil iron nucleus cylindrical (C.I.N.C. The coil iron nucleus cylindrical is a nonlinear electro radio in which the moving of the nucleus in a sense or in other causes change in inductance and can reach extreme values at the superposition of nucleus and coil centers. The variation of the inductance and the degree of freedom of movement of the nucleus can lead to a device with electromechanical conversion The aim of this paper is the determination and visualization of self inductance and mutual of the (C.I.N.C based on geometric dimensions and the displacement of the nucleus.  

  16. Multidisciplinary approach to cylindrical anisotropic metamaterials

    International Nuclear Information System (INIS)

    Anisotropic characteristics of cylindrically corrugated microstructures are analyzed in terms of their acoustic and electromagnetic (EM) behavior paying special attention to their differences and similarities. A simple analytical model has been developed using effective medium theory to understand the anisotropic features of both types of waves in terms of radial and angular components of the wave propagation velocity. The anisotropic constituent parameters have been obtained by measuring the resonances of cylindrical cavities, as well as from numerical simulations. This permits one to characterize propagation of acoustic and EM waves and to compare the fundamental anisotropic features generated by the corrugated effective medium. Anisotropic coefficients match closely in both physics fields but other relevant parameters show significant differences in the behavior of both types of waves. (paper)

  17. Omnidirectional, circularly polarized, cylindrical microstrip antenna

    Science.gov (United States)

    Stanton, Philip H. (Inventor)

    1985-01-01

    A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

  18. Nanolaminate Membranes as Cylindrical Telescope Reflectors

    Science.gov (United States)

    Dooley, Jennifer; Dragovan, Mark; Hickey, Gregory; Lih, Shyh-Shiu Lih

    2010-01-01

    A document discusses a proposal to use axially stretched metal nanolaminate membranes as lightweight parabolic cylindrical reflectors in the Dual Anamorphic Reflector Telescope (DART) - a planned spaceborne telescope in which the cylindrical reflectors would be arranged to obtain a point focus. The discussion brings together a combination of concepts reported separately in several prior NASA Tech Briefs articles, the most relevant being "Nanolaminate Mirrors With Integral Figure-Control Actuators" NPO -30221, Vol. 26, No. 5 (May 2002), page 90; and "Reflectors Made From Membranes Stretched Between Beams" NPO -30571, Vol. 33, No. 10 (October 2009), page 11a. The engineering issues receiving the greatest emphasis in the instant document are (1) the change in curvature associated with the Poisson contraction of a stretched nanolaminate reflector membrane and (2) the feasibility of using patches of poly(vinylidene fluoride) on the rear membrane surface as piezoelectric actuators to correct the surface figure for the effect of Poisson contraction and other shape errors.

  19. Characterization of plasticity and fracture of shell casing of lithium-ion cylindrical battery

    Science.gov (United States)

    Zhang, Xiaowei; Wierzbicki, Tomasz

    2015-04-01

    Most of the literature on lithium-ion battery cells is concerned with modeling of jellyroll with little attention to properties of shell casing. However, shell casing provides substantial strength and fracture resistance under mechanical loading and therefore must be an important part of modeling of lithium-ion batteries. The paper reports on a comprehensive test program on commercially available empty shell casing of 18650 lithium-ion cylindrical cells. Part of the tests was used to determine plastic and fracture properties from sub-size specimens cut from lateral part of the cans. The other part served to validate plasticity and fracture models under various loading conditions. The associated flow rule was used to simulate plasticity behavior and Modified Mohr-Coulomb (MMC) fracture model was adopted to predict crack initiation and propagation of shell casing. Simulation results confirmed that present plasticity and fracture models could predict global plastic behavior of the cells under different loading conditions. The jellyroll model with volumetric hardening was introduced to compare the performance of empty shell casing, bare jellyroll and complete battery cell. It was shown that in many loading situations, for example, three point bending of the cylindrical cells, the metallic shell casing provides most of mechanical resistance.

  20. Intermittent permeation of cylindrical nanopores by water

    OpenAIRE

    Allen, Rosalind; Melchionna, Simone; Hansen, Jean-Pierre

    2002-01-01

    Molecular Dynamics simulations of water molecules in nanometre sized cylindrical channels connecting two reservoirs show that the permeation of water is very sensitive to the channel radius and to electric polarization of the embedding material. At threshold, the permeation is {\\emph{intermittent}} on a nanosecond timescale, and strongly enhanced by the presence of an ion inside the channel, providing a possible mechanism for gating. Confined water remains surprisingly fluid and bulk-like. It...

  1. Mach disc formation in cylindrical recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C.E.; McQueen, R.G.; Marsh, S.P.

    1983-01-01

    Cylindrical recovery systems have been used to shock-load polymers to pressures exceeding 50 GPa. In order to determine the pressures generated in these recovery systems the formation of the Mach disc on axis and its approach to steady state was monitored. The relation of the Mach disc diameter to the lateral dimension of the high explosive used to compress the polymer samples was also investigated.

  2. Electronic quantum confinement in cylindrical potential well

    Science.gov (United States)

    Baltenkov, Arkadiy S.; Msezane, Alfred Z.

    2016-04-01

    The effects of quantum confinement on the momentum distribution of electrons confined within a cylindrical potential well have been analyzed. The motivation is to understand specific features of the momentum distribution of electrons when the electron behavior is completely controlled by the parameters of a non-isotropic potential cavity. It is shown that studying the solutions of the wave equation for an electron confined in a cylindrical potential well offers the possibility to analyze the confinement behavior of an electron executing one- or two-dimensional motion in the three-dimensional space within the framework of the same mathematical model. Some low-lying electronic states with different symmetries have been considered and the corresponding wave functions have been calculated; the behavior of their nodes and their peak positions with respect to the parameters of the cylindrical well has been analyzed. Additionally, the momentum distributions of electrons in these states have been calculated. The limiting cases of the ratio of the cylinder length H and its radius R0 have been considered; when the cylinder length H significantly exceeds its radius R0 and when the cylinder radius is much greater than its length. The cylindrical quantum confinement effects on the momentum distribution of electrons in these potential wells have been analyzed. The possible application of the results obtained here for the description of the general features in the behavior of electrons in nanowires with metallic type of conductivity (or nanotubes) and ultrathin epitaxial films (or graphene sheets) are discussed. Possible experiments are suggested where the quantum confinement can be manifested. Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by Gerardo Delgado Barrio, Andrey Solov'Yov, Pablo Villarreal, Rita Prosmiti.

  3. Numerical dynamo action in cylindrical containers

    Science.gov (United States)

    Nore, Caroline; Castanon Quiroz, Daniel; Guermond, Jean-Luc; Léorat, Jacques; Luddens, Francky

    2015-06-01

    The purpose of this paper is to present results from numerical simulations of dynamo action in relation with two magnetohydrodynamics (MHD) experiments using liquid sodium in cylindrical containers. The first one is the von Kármán sodium (VKS) experiment from Cadarache (France), the second one is a precession-driven dynamo experiment from the DREsden sodium facility for DYNamo and thermohydraulic studies (DRESDYN). Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014) - Elected submissions", edited by Adel Razek

  4. Mach disc formation in cylindrical recovery systems

    International Nuclear Information System (INIS)

    Cylindrical recovery systems have been used to shock-load polymers to pressures exceeding 50 GPa. In order to determine the pressures generated in these recovery systems the formation of the Mach disc on axis and its approach to steady state was monitored. The relation of the Mach disc diameter to the lateral dimension of the high explosive used to compress the polymer samples was also investigated

  5. Multiple Bifurcations of a Cylindrical Dynamical System

    OpenAIRE

    Han Ning; Cao Qingjie

    2016-01-01

    This paper focuses on multiple bifurcations of a cylindrical dynamical system, which is evolved from a rotating pendulum with SD oscillator. The rotating pendulum system exhibits the coupling dynamics property of the bistable state and conventional pendulum with the ho- moclinic orbits of the first and second type. A double Andronov-Hopf bifurcation, two saddle-node bifurcations of periodic orbits and a pair of homoclinic bifurcations are detected by using analytical analysis and nu- merical ...

  6. Magnetic guns with cylindrical permanent magnets

    Czech Academy of Sciences Publication Activity Database

    Vokoun, David; Beleggia, M.; Heller, Luděk

    2012-01-01

    Roč. 324, č. 9 (2012), s. 1715-1719. ISSN 0304-8853 R&D Projects: GA ČR(CZ) GAP107/11/0391; GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : permanent magnet * cylindrical magnet * Earnshaw's theorem * magnetic gun * magnetostatic interaction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.826, year: 2012 http://www.sciencedirect.com/science/article/pii/S0304885311008997

  7. On the incompressibility of cylindrical origami patterns

    OpenAIRE

    Bös, Friedrich; Vouga, Etienne; Gottesman, Omer; Wardetzky, Max

    2015-01-01

    The art and science of folding intricate three-dimensional structures out of paper has occupied artists, designers, engineers, and mathematicians for decades, culminating in the design of deployable structures and mechanical metamaterials. Here we investigate the axial compressibility of origami cylinders, i.e., cylindrical structures folded from rectangular sheets of paper. We prove, using geometric arguments, that a general fold pattern only allows for a finite number of \\emph{isometric} cy...

  8. Multidisciplinary approach to cylindrical anisotropic metamaterials

    OpenAIRE

    Carbonell Olivares, Jorge; Torrent Martí, Daniel; Diaz Rubio, Ana; Sánchez-Dehesa Moreno-Cid, José

    2011-01-01

    Anisotropic characteristics of cylindrically corrugated microstructures are analyzed in terms of their acoustic and electromagnetic (EM) behavior paying special attention to their differences and similarities. A simple analytical model has been developed using effective medium theory to understand the anisotropic features of both types of waves in terms of radial and angular components of the wave propagation velocity. The anisotropic constituent parameters have been obtained by measuring the...

  9. Free Vibration of Partially Supported Cylindrical Shells

    OpenAIRE

    Mirza, S.; Y. Alizadeh

    1995-01-01

    The effects of detached base length on the natural frequencies and modal shapes of cylindrical shell structures were investigated in this work. Some of the important applications for this type of problem can be found in the cracked fan and rotor blades that can be idealized as partially supported shells with varying unsupported lengths. A finite element model based on small deflection linear theory was developed to obtain numerical solutions for this class of problems. The numerical results w...

  10. Torsion of Elliptical Composite Cylindrical Shells

    OpenAIRE

    Haynie, Waddy

    2007-01-01

    The response of elliptical composite cylindrical shells under torsion is studied. The torsional condition is developed by rotating one end of the cylinder relative to the other. Prebuckling, buckling, and postbuckling responses are examined, and material failure is considered. Four elliptical cross sections, defined by their aspect ratio, the ratio of minor to major radii, are considered: 1.00 (circular), 0.85, 0.70, and 0.55. Two overall cylinder sizes are studied; a small size with a radius...

  11. Cylindric-like algebras and algebraic logic

    CERN Document Server

    Ferenczi, Miklós; Németi, István

    2013-01-01

    Algebraic logic is a subject in the interface between logic, algebra and geometry, it has strong connections with category theory and combinatorics. Tarski’s quest for finding structure in logic leads to cylindric-like algebras as studied in this book, they are among the main players in Tarskian algebraic logic. Cylindric algebra theory can be viewed in many ways:  as an algebraic form of definability theory, as a study of higher-dimensional relations, as an enrichment of Boolean Algebra theory, or, as logic in geometric form (“cylindric” in the name refers to geometric aspects). Cylindric-like algebras have a wide range of applications, in, e.g., natural language theory, data-base theory, stochastics, and even in relativity theory. The present volume, consisting of 18 survey papers, intends to give an overview of the main achievements and new research directions in the past 30 years, since the publication of the Henkin-Monk-Tarski monographs. It is dedicated to the memory of Leon Henkin.

  12. Reactor core of FBR type reactor

    International Nuclear Information System (INIS)

    Gas sealed assemblies are disposed in rows between reactor core fuel assemblies. The gas sealed assembly incorporates inflowed sodium (coolants) and sealed gas in a gas sealing cylinder and an inner hollow of a wrapper tube. A cylindrical heat generating member is disposed in the gas sealing cylinder. The sealed gas is compressed by a discharging pressure of a pump by way of sodium in the wrapper tube. During normal operation, the liquid level of the coolants is present above than a backwarding flow hole, and the temperature of the coolants is raised by the cylindrical heat generation member to raise the temperature of sodium in the backwarding flow hole. High temperature sodium is mixed with low temperature sodium from a lower flow hole at the lower portion of the backwarding flow hole, and sodium at a leak flow hole becomes sodium at a middle temperature. The temperature of the middle temperature sodium is detected by a thermometer. With such procedures, the liquid level in the gas sealed assembly can be detected and confirmed during normal operation. (I.N.)

  13. Characteristics of Left-Right Spiral Hollow Cylindrical Roller

    Institute of Scientific and Technical Information of China (English)

    Liming Lu; Qiping Chen; Yujiang Qin

    2015-01-01

    Based on new rolling⁃sliding compound bearings, the wear between the one⁃way spiral hollow cylindrical roller and the ribs of the inner and outer ring of rolling⁃sliding compound bearings is reduced by innovational structural design. A new left⁃right spiral hollow cylindrical roller is proposed to replace the one⁃way spiral hollow cylindrical roller. The finite element analysis models of ordinary cylindrical rollers, one⁃way spiral hollow cylindrical rollers and left⁃right spiral hollow cylindrical rollers are respectively established by ABAQUS. The axial displacement of their center mass and the stress distribution of left⁃right spiral hollow cylindrical rollers are compared and analyzed. Theoretical study results show that this new left⁃right spiral hollow cylindrical roller not only inherits the advantages of one⁃way spiral hollow cylindrical rollers, but also avoids the axial offset and the serious wear of the one⁃way spiral hollow cylindrical roller. And the theory research conclusion is verified by the experiment. The left⁃right spiral hollow cylindrical roller has the advantages to overcome boundary stress concentration like logarithmic convex roller. The rolling⁃sliding compound bearings equipped with the new rollers can be better to adapt to the impact of vibration load.

  14. Stitching interferometry for cylindrical optics with large angular aperture

    International Nuclear Information System (INIS)

    Stitching interferometry is an attractive method for measuring optics with large apertures. However, existing stitching algorithms are not suitable for measuring cylindrical optics, because the misalignment aberrations in cylindrical interferometry are more complicated than those in plane, spherical and aspherical measurements. This paper presents a stitching algorithm for measuring cylindrical optics with large angular apertures. With it, we use five aberrations (i.e. piston, tilt, tip, defocus and twist) to describe the possible misalignments of the tested cylindrical surface and to build the cylindrical stitching model. Using this model allows us to calculate the relative misalignment aberrations of subapertures from their overlapped areas, so that the full aperture map of a cylindrical surface is obtained by compensating for these misalignment aberrations. In experiment, a cylindrical lens with an angular aperture over 150° is measured, thus demonstrating the feasibility and validity of the proposed method. (paper)

  15. Calculation models for a nuclear reactor

    International Nuclear Information System (INIS)

    Determination of different parameters of nuclear reactors requires neutron transport calculations. Due to complicity of geometry and material composition of the reactor core, neutron calculations were performed for simplified models of the real arrangement. In frame of the present work two models were used for calculations. First, an elementary cell model was used to prepare cross section data set for a homogenized-core reactor model. The homogenized-core reactor model was then used to perform neutron transport calculation. The nuclear reactor is a tank-shaped thermal reactor. The semi-cylindrical core arrangement consists of aluminum made fuel bundles immersed in water which acts as a moderator as well as a coolant. Each fuel bundle consists of aluminum cladded fuel rods arranged in square lattices. (author)

  16. Performance analysis of cylindrical metal hydride beds with various heat exchange options

    Energy Technology Data Exchange (ETDEWEB)

    Satya Sekhar, B. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Kolesnikov, A.; Moropeng, M.L. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Private Bag X680, Pretoria 0001 (South Africa); Tarasov, B.P. [Laboratory of Hydrogen Storage Materials, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Prospect Semenova, 1, Chernogolovka 142432 (Russian Federation); Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • 3D numerical model for the comparison of H{sub 2} uptake performances in MH reactors. • 4 options of heat exchange between heat transfer fluid and MH in cylindrical reactor compared. • Straight tube internal heat exchanger. • Helical coil internal heat exchanger. • External heat exchange without and with transversal fins in the MH reactor. - Abstract: A 3D numerical heat-and-mass transfer model was used for the comparison of H{sub 2} uptake performances of powdered cylindrical MH beds comprising MmNi{sub 4.6}Al{sub 0.4} hydrogen storage material. The considered options of heat exchange between the MH and a heat transfer fluid included internal cooling using straight (I) or helically coiled (II) tubing, as well as external cooling of the MH bed without (III) and with (IV) transversal fins. The dynamic performances of these layouts were compared based on the numerical simulation. The effect of heat transfer coefficient was also analysed.

  17. N Reactor

    Data.gov (United States)

    Federal Laboratory Consortium — The last of Hanfordqaodmasdkwaspemas7ajkqlsmdqpakldnzsdflss nine plutonium production reactors to be built was the N Reactor.This reactor was called a dual purpose...

  18. EAARL Coastal Topography--Eastern Florida, Post-Hurricane Frances, 2004: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the eastern Florida coastline was produced from remotely...

  19. EAARL Coastal Topography--Western Florida, Post-Hurricane Charley, 2004: Seamless (Bare Earth and Submerged)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A seamless (bare-earth and submerged) elevation map (also known as a Digital Elevation Model, or DEM) of a portion of western Florida, post-Hurricane Charley, was...

  20. 2010 USGS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Chandeleur Islands, Louisiana (Bare-Earth)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the Chandeleur Islands, Louisiana, was produced from remotely...

  1. EAARL Coastal Topography--Assateague Island National Seashore, 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth elevation map (also known as a Digital Elevation Model, or DEM) of the Assateague Island National Seashore in Virginia and Maryland was produced from...

  2. LiDAR Derived Bare Earth Digital Elevation Model: Camas National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This dataset represents the Camas National Wildlife Refuge survey area in Jefferson and Clark County, ID. This bare earth digital elevation model (DEM) represent...

  3. Simulation of metal hydride reactor with aluminium foam matrix

    International Nuclear Information System (INIS)

    'Full text:' A 1-D model has been developed for testing different designs of hydride reactors. The computer program can simulate a complete reactor or a part of it in planar, cylindrical or spherical geometry. It reproduces an experimental loop: absorption followed by desorption and calculates heat transfer during the reaction. Simulation results have been confronted to experimental data with very good correlation. A reactor with a heat transfer matrix inside, such as aluminum foam, can be simulated. We have evaluated the size limits of a reactor and the category of foam that preserves the good reaction kinetic performances of a reactor filled with LaNi5. (author)

  4. A TFD model for the Electrospheres of Bare Strange Quark Stars

    CERN Document Server

    Guo, Hai-Chuan; Zhang, Cheng-Min

    2007-01-01

    We study the layer of electrons on bare strange star surfaces, taking the Dirac exchange-energy into account. Because electrons are fermions, the electron wave function must be of exchange-antisymmetry. The Dirac exchange-energy originates, consequently, from the exchange-antisymmetry of electron wave functions. This consideration may result in changing the electron distribution and the electric field on the surface of bare strange star. The strong magnetic field effect on the structures of the electrospheres is also discussed.

  5. Biolimus-eluting stents with biodegradable polymer versus bare-metal stents in acute myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Kelbæk, Henning; Taniwaki, Masanori;

    2014-01-01

    BACKGROUND: This study sought to determine whether the 1-year differences in major adverse cardiac event between a stent eluting biolimus from a biodegradable polymer and bare-metal stents (BMSs) in the COMFORTABLE trial (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Meta......, BES continued to improve cardiovascular events compared with BMS beyond 1 year. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NTC00962416....

  6. Neutronic parameters calculations of a CANDU reactor

    International Nuclear Information System (INIS)

    Neutronic calculations that reproduce in a simplified way some aspects of a CANDU reactor design were performed. Starting from some prefixed reactor parameters, cylindrical and uniform iron adjuster rods were designed. An appropriate refueling scheme was established, defininig in a 2 zones model their dimensions and exit burnups. The calculations have been done using the codes WIMS-D4 (cell), SNOD (reactivity device simulations) and PUMA (reactor). Comparing with similar calculations done with codes and models usually employed for CANDU design, it is concluded that the models and methods used are appropriate. (Author)

  7. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  8. Localized fluid collection of hepatic bare area in children with blunt abdominal trauma

    International Nuclear Information System (INIS)

    To investigate the incidence and significance of localized fluid collection in the hepatic bare area resulting from blunt abdominal trauma in children. We retrospectively reviewed the CT scans and medical records of eighty children with blunt abdominal trauma and evaluated the incidence of fluid collection in the hepatic bare area. The findings were correlated with the presence of injury to adjacent organs. Fluid collection in the hepatic bare area was noted in 23 of 80 patients (28.7%). Associated organ injuries included liver laceration (17/23), contusion of the right hemidiaphragm (7/23), right adrenal injury (5/23), and right renal injury (5/23). In one patient, organic injury was not detected in spite of fluid collection in the hepatic bare area. Eight of 23 patients (34.8%) showed fluid collection in this area, but not intraperitoneally. Fluid collection in the hepatic bare area after blunt abdominal trauma was noted in about 30% of patients and was frequently accompanied by injury to adjacent organs. Since right hemidiaphragmatic contusion associated with fluid collection in the bare area was not a uncommon CT finding, close observation of the condition is warranted. (author)

  9. Waves in inhomogeneous plasma of cylindrical geometry

    International Nuclear Information System (INIS)

    The conductivity tensor of a hot and inhomogeneous plasma has been calculated for a cylindrical geometry using Vlasov equations. The method used consists in a perturbation method involving the first integrals of the unperturbed movement. The conductivity tensor will be particularly useful for dealing with stability problems. In the case of a cold plasma the wave equation giving the electric fields as a function of the radius is obtained. This equation shows the existence of resonant layers which lead to an absorption analogous to the Landau absorption in a hot plasma. (author)

  10. OPTIMAL THICKNESS OF A CYLINDRICAL SHELL

    Directory of Open Access Journals (Sweden)

    Paul Ziemann

    2015-01-01

    Full Text Available In this paper an optimization problem for a cylindrical shell is discussed. The aim is to look for an optimal thickness of a shell to minimize the deformation under an applied external force. As a side condition, the volume of the shell has to stay constant during the optimization process. The deflection is calculated using an approach from shell theory. The resulting control-to-state operator is investigated analytically and a corresponding optimal control problem is formulated. Moreover, necessary conditions for an optimal solution are stated and numerical solutions are presented for different examples.

  11. Enhanced Performance of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma

  12. Kaluza-Klein Magnetized Cylindrical Wormhole

    CERN Document Server

    Hashemi, S Sedigheh

    2015-01-01

    A new exact vacuum solution in five dimensions, which describes a magnetized cylindrical wormhole in $3+1$ dimensions is presented. The magnetic field lines are stretched along the wormhole throat and are concentrated near to it. We study the motion of neutral and charged test particles under the influence of the magnetized wormhole. The effective potential for a neutral test particle around and across the magnetized wormhole has a repulsive character. The total magnetic flux on either side of the wormhole is obtained. We present analytic expressions which show regions in which the null energy condition is violated.

  13. Cullet Manufacture Using the Cylindrical Induction Melter

    International Nuclear Information System (INIS)

    The base process for vitrification of the Am/Cm solution stored in F-canyon uses 25SrABS cullet as the glass former. A small portion of the cullet used in the SRTC development work was purchased from Corning while the majority was made in the 5 inch Cylindrical Induction Melter (CIM5). Task 1.01 of TTR-NMSS/SE-006, Additional Am-Cm Process Development Studies, requested that a process for the glass former (cullet) fabrication be specified. This report provides the process details for 25SrAB cullet production thereby satisfying Task 1.01

  14. Statistical entropy of a cylindrical black hole

    International Nuclear Information System (INIS)

    By using the method of quantum statistics, it was directly derived the partition function of the bosonic and fermionic field in a cylindrical black hole. Then via the improved brick-wall method, the membrane model, it was obtained that if chosen a proper parameter, the entropy of the black hole is proportional to the area of the horizon. In the results, the stripped term and the divergent logarithmic term in the original brick-wall method no longer exist. In the whole process, it was not taken any approximation. It was offered a new simple and direct way of calculating the entropy of different complicated black holes

  15. Design of a cylindrical Cerenkov detector

    International Nuclear Information System (INIS)

    A study of a cylindrical Cerenkov detector, with the aim of investigating a possible application of such a detector for distinguishing between pions and kaons, in the range of a few GeV/c, has been carried out. The detector design could, for example, be used for the experimental B-physics study with the upgraded collider detectors at the Fermilab Tevatron. Simulation methods were used to find the response of several configurations of such a detector as a function of the incident pion and kaon energies in the energy range of a few giga electron volts. It is shown that a straightforward configuration based on conventional materials could work

  16. A cylindrical furnace for absorption spectral studies

    Indian Academy of Sciences (India)

    R Venkatasubramanian

    2001-06-01

    A cylindrical furnace with three heating zones, capable of providing a temperature of 1100°C, has been fabricated to enable recording of absorption spectra of high temperature species. The temperature of the furnace can be controlled to ± 1°C of the set temperature. The salient feature of this furnace is that the material being heated can be prevented from depositing on the windows of the absorption cell by maintaining a higher temperature at both the ends of the absorption cell.

  17. Free vibrations of circular cylindrical shells

    CERN Document Server

    Armenàkas, Anthony E; Herrmann, George

    2013-01-01

    Free Vibrations of Circular Cylindrical Shells deals with thin-walled structures that undergo dynamic loads application, thereby resulting in some vibrations. Part I discusses the treatment of problems associated with the propagation of plane harmonic waves in a hollow circular cylinder. In such search for solutions, the text employs the framework of the three-dimensional theory of elasticity. The text explains the use of tables of natural frequencies and graphs of representative mode shapes of harmonic elastic waves bounding in an infinitely long isotropic hollow cylinder. The tables are

  18. Cylindrical ionization chamber with compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88Y) when the chamber is filled with a mixture of Kr+0.2% H2 under a pressure of 25 atm

  19. Cylindrical ionization chamber on compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is described. The chamber is used in experiments to search for double positron decay and conversion of atom electron into positron in Kr78. The working substance of the chamber is krypton. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. Energy resolution is 2.1% for 1.84 MeV energy (the gamma quantum source is 88Y) when using the chamber filled with Kr+0.2%H2 mixture at pressure of 25 atm

  20. Cellular Cell Bifurcation of Cylindrical Detonations

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-Lai; JIANG Zong-Lin; WANG Chun; ZHANG Fan

    2008-01-01

    Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From the simulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearly self-sustained mechanism of detonations and finally lead to cell bifurcations.

  1. Cylindrical metamaterial-based subwavelength antenna

    DEFF Research Database (Denmark)

    Erentok, Aycan; Kim, Oleksiy S.; Arslanagic, Samel

    2009-01-01

    A subwavelength monopole antenna radiating in the presence of a truncated cylindrical shell, which has a capped top face and is made of a negative permittivity metamaterial, is analyzed numerically by a method of moments for the volume-surface integral equation oil the one hand, and a finite...... element method on the other hand. It is shown that a center-fed truncated cylinder, in contrast to an infinite cylinder, provides subwavelength resonances, thus suggesting the possibility, of having a subwavelength antenna system....

  2. Stress-strained state of the magnetic circuit of a cylindrical linear induction pump

    International Nuclear Information System (INIS)

    The stress-strained state of the magnetic circuit structures of cylindrical linear induction pumps for the secondary coolant circuit of the BOR-60 reactor is determined. It is shown that when choosing a radial clearance between the inductor and the channel in structures without tread rings (they are used for preventing from magnetic circuits bending) one should take into account magnetic circuit packet deflections from temperature and magnetic forces. Contact forces between the packets and the channel in constructions with tread rings are determined. The formulas for calculating packet deflections are indicated and recommendations for designing magnetic circuits without tread rings are given

  3. Solution of transport equation in integral form in one-dimensional cylindrical geometry with linear anisotropic scattering

    International Nuclear Information System (INIS)

    Transport equation in one-dimensional geometry with linear-anisotropic scattering is written in integral form. Closed system of integral equations relative to current harmonics - φ0(r) and φ1(r) is obtained. The system of integral equations is used as the basis for the PLINTC program. Numerical results on scalar current distribution in cylindrical reactor cells in single-velocity approximation are obtained. Comparison with numerical results obtained through other programs is presented. 10 refs., 1 fig., 3 tabs

  4. BCG: A code for solving the space-dependent slowing-down problem in multiregion cylindrical systems

    International Nuclear Information System (INIS)

    The BCG code to compute pointwise spectra for the slowing-down problem in multiregion cylindrical systems is presented. The code solves a set of balance equations and interface current relations at each energy point in a grid which is the union of the individual total cross section energy grids of the materials in the system and at an arbitrary number of spatial zones. Results for a simplified fast reactor fuel cell illustrate the high resolution that can be obtained with the code

  5. Multimode interaction in axially excited cylindrical shells

    Directory of Open Access Journals (Sweden)

    Silva F. M. A.

    2014-01-01

    Full Text Available Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural frequencies. The shell is modelled using the Donnell nonlinear shallow shell theory and the discretized equations of motion are obtained by applying the Galerkin method. For this, a modal solution that takes into account the modal interaction among the relevant modes and the influence of their companion modes (modes with rotational symmetry, which satisfies the boundary and continuity conditions of the shell, is derived. Special attention is given to the 1:1:1:1 internal resonance (four interacting modes. Solving numerically the governing equations of motion and using several tools of nonlinear dynamics, a detailed parametric analysis is conducted to clarify the influence of the internal resonances on the bifurcations, stability boundaries, nonlinear vibration modes and basins of attraction of the structure.

  6. Data fusion for cylindrical form measurements

    Science.gov (United States)

    Liu, Pei; Jusko, Otto; Tutsch, Rainer

    2015-12-01

    For high-precision form measurements of cylindrical workpieces form profiles such as roundness and straightness profiles are independently acquired via a bird-cage strategy. The 3D point cloud reconstructed by fusing these intersected profiles is meaningful in dimension and form assessment for cylinder, since enhanced accuracy can be achieved by fusion results. Moreover, it plays an important role as the input to other calculations. However, these data cannot be accurately aligned in form reconstruction, due to random absolute offsets in profiles and a lack of absolute positions. Therefore, we propose an approach to data fusion of these profiles to reconstruct cylindrical form. The uncertainties of the fused profile are evaluated, taking an individual contribution of a single profile and a global contribution of all profiles into account. The associated uncertainties are propagated using the Monte Carlo method. Experimental study results indicate that the data fusion procedure improves the accuracy of available datasets. After fusion, all available data points are capable of being used in the form assessment.

  7. Forced Vibration Analysis for a FGPM Cylindrical Shell

    Directory of Open Access Journals (Sweden)

    Hong-Liang Dai

    2013-01-01

    Full Text Available This article presents an analytical study for forced vibration of a cylindrical shell which is composed of a functionally graded piezoelectric material (FGPM. The cylindrical shell is assumed to have two-constituent material distributions through the thickness of the structure, and material properties of the cylindrical shell are assumed to vary according to a power-law distribution in terms of the volume fractions for constituent materials, the exact solution for the forced vibration problem is presented. Numerical results are presented to show the effect of electric excitation, thermal load, mechanical load and volume exponent on the static and force vibration of the FGPM cylindrical shell. The goal of this investigation is to optimize the FGPM cylindrical shell in engineering, also the present solution can be used in the forced vibration analysis of cylindrical smart elements.

  8. Inflation of Stressed Cylindrical Tubes: An Experimental Study

    OpenAIRE

    Guo, Zhiming; Wang, Shibin; Li, Linan; Ji, Hongwei; Wang, Zhiyong; Cai, Songbao

    2013-01-01

    The inflation of an initially stressed cylindrical shell provides a good illustration of the phenomenon of the initiation and propagation of an instability, which shares the same mathematical and mechanical features with a variety of other strain localization phenomena in engineering structures and materials. The high speed CCD camera and digital image processing system were used to measure the 3D shape of the inflated cylindrical tube. The localized bulge of a cylindrical tube with closed en...

  9. The need to address the larger universe of HEU-fueled reactors, including critical assemblies, pulsed reactors and propulsion reactors

    International Nuclear Information System (INIS)

    Full text: The RERTR program has focused thus far primarily on ending shipments of HEU fuel to research reactors. This has resulted in giving highest priority to reactors with steady thermal powers of 1 megawatt or more, because they require regular refuelling. Critical facilities and pulsed reactors can also of serious concern, because some of them contain very large amounts of barely-irradiated HEU and plutonium. They could be costly to convert - and conversion to LEU may be impractical for fast-neutron critical assemblies. An assessment should be carried out first, therefore, as to which are still needed. Critical assemblies are required today primarily to benchmark Monte Carlo neutron-transport codes. Perhaps the world nuclear community could share a few instead of each reactor-design institute having its own. There is also a whole universe of HEU-fuelled pressurized-water reactors used to power submarines and other types of nuclear-powered ships. These reactors collectively require much more HEU fuel each year than research reactors. The risk of HEU diversion from their fuel cycles is not zero but it is difficult for outsiders to discuss conversion because of the fuel designs are classified. This makes the conversion of Russia's civilian icebreaker reactors of particular interest because issues of classified fuel design are less problematic and these reactors load annually fuel containing about 400 kg of U-235. Another reason for interest in developing LEU fuel for these reactors is that the KLT-40 icebreaker reactor is being adapted for a floating nuclear power plant. Finally, the research-reactor community is, in any case, faced with developing fuels that can operate at power-reactor-fuel temperatures because there are a few high-powered research reactors that operate in this temperature range. (author)

  10. A Method to Solve Multigroup P3 Equations in Cylindrical Geometry

    International Nuclear Information System (INIS)

    To determine the space-energy distribution of thermal neutrons in a reactor cell a combination of the spherical harmonics method and multigroup procedure has been chosen. In P-3 approximation and cylindrical geometry such a scheme implies the solution of an inhomogeneous system of six ordinary first order differential equations. The general solution of the corresponding homogeneous system is known in analytical form. The present work shows how the free term of the system can be approximated in order to find a particular solution, and thus the general solution, of the inhomogeneous system. The procedure has been applied to calculate thermal spectra in a number of different reactor cells. Some results are presented and discussed. (author)

  11. Collision probability method for discrete presentation of space in cylindrical cell

    International Nuclear Information System (INIS)

    A suitable numerical method for integration of one-group integral transport equation is obtained by series expansion of flux and neutron source by radius squared, when calculating the parameters of cylindrically symmetric reactor cell. Separation of variables in (x,y) plane enables analytical integration in one direction and efficient Gauss quadrature formula in the second direction. White boundary condition is used for determining the neutron balance. Suitable choice of spatial points distribution in the fuel and moderator condenses the procedure for determining the transport matrix and accelerates the convergence when calculating the absorption in the reactor cell. In comparison to other collision probability methods the proposed procedure is a simple mathematical model which demands smaller computer capacity and shorter computing time

  12. Karst bare slope soil erosion and soil quality: a simulation case study

    Directory of Open Access Journals (Sweden)

    Q. Dai

    2015-06-01

    Full Text Available The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1, no bottom load loss is produced on the surface, and surface and underground runoff and sediment production is increased with the increasing of rainfall intensity; secondly, surface runoff and sediment production reduced with increased underground pore fissure degree, while underground runoff and sediment production increased; thirdly, raindrops hit the surface, forming a crust with rainfall duration. The formation of crusts increases surface runoff erosion and reduces soil infiltration rate. Increasing of surface runoff erosion damaged crust and increased soil seepage rate. Raindrops continued to hit the surface, leading the formation of crust. Soil permeability showed volatility which were from reduction to increases and reduction, and so on. Surface and subsurface runoff were volatility with rainfall duration; fourthly, when rock bareness ratio is 50% and rainfall intensities are 30 and 50 mm h−1, runoff is not produced on the surface, and the slope runoff and sediment production presents a fluctuating change with increased rock bareness ratio; fifthly, the correlation degree between the slope runoff and sediment production and all factors are as follows: rainfall intensity > rainfall duration > underground pore fissure degree > bed rock bareness ratio.

  13. Study of cylindrical nuclear heat source internally cooled by liquid metal circulation

    International Nuclear Information System (INIS)

    In view of fuel management, the early adoption of 14-month fuel shuffling in PWR was a dramatically long refueling period compared to that of the fossil power plant. It is well known that the material integrity of the fuel and the associated structures is the key variable in limiting the fuel residence time in the reactor core. With this view, if one recall that one of advantages of nuclear fuel over the fossil fuel is to convert the fertile material into the fissile while the fuel is burning, it is possible to design reactor core of very long life, that is, more that about 10 years as long as the structural integrity of the fuel is guaranteed. The idea of the long life core may significantly diversify nuclear power source utilization since we may solve many problems in the areas of fuel handling and transportation, waste disposition, reactor operation, nuclear proliferation. In this study, an idea of secure nuclear heat source has been presented with the assumption of possible long-life core. The nuclear heat source of cylindrical shape includes the fuel, the coolant and all the other control devices in a single module which can be manufactured and assembled in a factory. With simple installation effort on the site, the cylindrical nuclear heat source can be augmented with the secondary system which is designed to convert the heat into the other useful form of energy. The design analysis models have been developed for the presented generic structure of the liquid metal cooled reactor of cylinder. The size, power rating and the other important design parameters have been presented. (author)

  14. Rotating cylindrical wormholes and energy conditions

    CERN Document Server

    Bronnikov, K A

    2015-01-01

    We seek wormholes among rotating cylindrically symmetric configurations in general relativity. Exact wormhole solutions are presented with such sources of gravity as a massless scalar field, a cosmological constant, and a scalar field with an exponential potential. However, none of these solutions are asymptotically flat, which excludes the existence of wormhole entrances as local objects in our Universe. To overcome this difficulty, we try to build configurations with flat asymptotic regions using the cut-and-paste procedure: on both sides of the throat, a wormhole solution is matched to a properly chosen region of flat space-time at some surfaces $\\Sigma_-$ and $\\Sigma_+$. It is shown, however, that if the source of gravity in the throat region is a scalar field with an arbitrary potential, then one or both thin shells appearing on $\\Sigma_-$ and $\\Sigma_+$ inevitably violate the null energy condition. Thus, although rotating wormhole solutions are easily found without exotic matter, such matter is still ne...

  15. Study of Cylindrical Honeycomb Solar Collector

    Directory of Open Access Journals (Sweden)

    Atish Mozumder

    2014-01-01

    Full Text Available We present the results of our investigation on cylindrical honeycomb solar collector. The honeycomb has been fabricated with transparent cellulose triacetate polymer sheets. Insulation characteristics of the honeycomb were studied by varying the separation between the honeycomb and the absorber plate. The optimal value of the separation was found to be 3.3 mm for which the heat transfer coefficient is 3.06 W m−2 K−1. This supports result of previous similar experiments. Further we test the honeycomb through a field experiment conducted in Delhi (28.6°N, 77°E and found that when the incident angle of the solar radiation is within 20° then the performance of the system with the honeycomb is better than the one without the honeycomb.

  16. SPSM and its application in cylindrical shells

    Science.gov (United States)

    Nie, Wu; Zhou, Su-Lian; Peng, Hui

    2008-03-01

    In naval architectures, the structure of prismatic shell is used widely. But there is no suitable method to analyze this kind of structure. Stiffened prismatic shell method (SPSM) presented in this paper, is one of the harmonic semi-analytic methods. Theoretically, strong stiffened structure can be analyzed economically and accurately. SPSM is based on the analytical solution of the governing differential equations for orthotropic cylindrical shells. In these differential equations, the torsional stiffness, bending stiffness and the exact position of each stiffener are taken into account with the Heaviside singular function. An algorithm is introduced, in which the actions of stiffeners on shells are replaced by external loads at each stiffener position. Stiffened shells can be computed as non-stiffened shells. Eventually, the displacement solution of the equations is acquired by the introduction of Green function. The stresses in a corrugated transverse bulkhead without pier base of an oil tanker are computed by using SPSM.

  17. Cylindrical wormholes with positive cosmological constant

    CERN Document Server

    Richarte, Mart'\\in G

    2013-01-01

    We construct cylindrical, traversable wormholes with finite radii by taking into account the cut-and-paste procedure for the case of cosmic string manifolds with a positive cosmological constant. Under reasonable assumptions about the equation of state of the matter located at the shell, we find that the wormhole throat undergoes a monotonous evolution provided it moves at a constant velocity. In order to explore the dynamical nonlinear behaviour of the wormhole throat, we consider that the matter at the shell is supported by anisotropic Chaplygin gas, anti-Chaplygin gas, or a mixed of Chaplygin and anti-Chaplygin gases implying that wormholes could suffer an accelerated expansion or contraction but the oscillatory behavior seems to be forbidden.

  18. Analysis of a cylindrical imploding shock wave

    International Nuclear Information System (INIS)

    the self-similar solution of the gasdynamic equations of a strong cylindrical shock wave moving through an ideal gas, with γ = csub(p)/csub(v), is considered. These equations are greatly simplified following the transformation of the reduced velocity U1 (xi) → U1 = 1/2(γ + 1 ) (U + xi). The requirement of a single maximum pressure, dsub(xi)P = 0, leads to an analytical determination of the self-similarity exponent α(γ). For gases with γ = 2 + 3sup(1/2), this maximum ensues right at the shock front and the pressure distribution then decreases monotonically. The postulate of analyticity by Gelfand and Butler is shown to concur with the requirement dsub(xi)P 0. The saturated density of the gas left in the wake of the shock is computed and - U is shown to be the reduced velocity of sound at P = P sub(m). (author)

  19. Mathematical model of cylindrical form tolerance

    Institute of Scientific and Technical Information of China (English)

    蔡敏; 杨将新; 吴昭同

    2004-01-01

    Tolerance is essential for integration of CAD and CAM. Unfortunately, the meaning of tolerances in the national standard is expressed in graphical and language forms and is not adaptable for expression, processing and data transferring with computers. How to interpret its semantics is becoming a focus of relevant studies. This work based on the mathematical definition of form tolerance in ANSI Y 14.5.1 M-1994, established the mathematical model of form tolerance for cylindrical feature. First, each tolerance in the national standard was established by vector equation. Then on the foundation of toler-ance's mathematical definition theory, each tolerance zone's mathematical model was established by inequality based on degrees of feature. At last the variance area of each tolerance zone is derived. This model can interpret the semantics of form tolerance exactly and completely.

  20. Mathematical model of cylindrical form tolerance

    Institute of Scientific and Technical Information of China (English)

    蔡敏; 杨将新; 吴昭同

    2004-01-01

    Tolerance is essential for integration of CAD and CAM.Unfortunately,the meaning of tolerances in the national standard is expressed in graphical and language forms and is not adaptable for expression,processing and data transferring with computers.How to interpret its semantics is becoming a focus of relevant studies.This work based on the mathematical definition of form tolerance in ANSI Y 14.5.1 M-1994,established the mathematical model of form tolerance for cylindrical feature.First,each tolerance in the national standard was established by vector equation.Then on the foundation of tolerance's mathematical definition theory,each tolerance zone's mathematical model was established by inequality based on degrees of feature.At last the variance area of each tolerance zone is derived.This model can interpret the semantics of form tolerance exactly and completely.

  1. Indentation of Ellipsoidal and Cylindrical Elastic Shells

    KAUST Repository

    Vella, Dominic

    2012-10-01

    Thin shells are found in nature at scales ranging from viruses to hens\\' eggs; the stiffness of such shells is essential for their function. We present the results of numerical simulations and theoretical analyses for the indentation of ellipsoidal and cylindrical elastic shells, considering both pressurized and unpressurized shells. We provide a theoretical foundation for the experimental findings of Lazarus etal. [following paper, Phys. Rev. Lett. 109, 144301 (2012)PRLTAO0031-9007] and for previous work inferring the turgor pressure of bacteria from measurements of their indentation stiffness; we also identify a new regime at large indentation. We show that the indentation stiffness of convex shells is dominated by either the mean or Gaussian curvature of the shell depending on the pressurization and indentation depth. Our results reveal how geometry rules the rigidity of shells. © 2012 American Physical Society.

  2. Confined detonations with cylindrical and spherical symmetry

    International Nuclear Information System (INIS)

    An imploding spherical or cylindrical detonation, starting in the interface of the detonantion with an external inert media, used as a reflector, creates on it a strong shock wave moving outward from the interface. An initially weak shock wave appears in the detonated media that travels toward the center, and it could reach the detonation wave, enforcing it in its process of implosion. To describe the fluid field, the Euler s equations are solved by means of expansions valid for the early stages of the process. Isentropic of the type P/pγ-K for the detonated and compressed inert media are used. For liquid or solid reflectors a more appropriate equation is used. (Author) 8 refs

  3. Potential flow inside an evaporating cylindrical line.

    Science.gov (United States)

    Petsi, A J; Burganos, V N

    2005-10-01

    An analytical solution to the problem of potential flow inside an evaporating line is obtained. The line is shaped as a half-cylinder lying on a substrate, and evaporates with either pinned or depinned contact lines. The solution is provided through the technique of separation of variables in the velocity potential and stream function formulations. Based on the flow field calculations, it is estimated that the coffee-stain phenomenon should be expected even for uniform evaporation flux throughout the cylindrical surface, provided that the contact lines remain anchored. A simple expression for the velocity potential is also suggested, which reproduces the local velocity vector with excellent accuracy. The vertically averaged velocity is calculated also for other contact line values, revealing for any value an outward liquid flow for pinned lines as opposed to inward flow for depinned lines. PMID:16383581

  4. Free Vibration of Partially Supported Cylindrical Shells

    Directory of Open Access Journals (Sweden)

    S. Mirza

    1995-01-01

    Full Text Available The effects of detached base length on the natural frequencies and modal shapes of cylindrical shell structures were investigated in this work. Some of the important applications for this type of problem can be found in the cracked fan and rotor blades that can be idealized as partially supported shells with varying unsupported lengths. A finite element model based on small deflection linear theory was developed to obtain numerical solutions for this class of problems. The numerical results were generated for shallow shells and some of the degenerate cases are compared with other results available in the literature. The computations presented here involve a wide range of variables: material properties, aspect ratios, support conditions, and radius to base ratio.

  5. Diamond deposition on thin cylindrical substrates

    Directory of Open Access Journals (Sweden)

    GORDANA S. RISTIĆ

    2011-03-01

    Full Text Available Diamond coatings were deposited onto different cylindrical substrates (Cu, SiC, W and Mo by the hot filament chemical vapor deposition (CVD method. Continuous, adhered and well-faceted crystalline coatings of diamond were obtained on Cu-wire using a special pretreatment with a mixture of diamond and metal powders as well as carefully controlled deposition at lower power. Diamond deposition on SiC-fiber gave continuous and uniform coatings when only the filament power was properly selected. Uniform, homogeneous, euchedral diamond coatings on W- and Mo-wires, attained at a higher filament power, confirmed once more the convenience of refractory metals as substrates for diamond deposition by the CVD technique. Characterization of the obtained coatings was realized using scanning electron microscopy (SEM. The obtained results are compared with the literature data. Differences are discussed with regard to the chemical nature of the substrates as well as their thermophysical characteristics.

  6. Reactor Physics

    International Nuclear Information System (INIS)

    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised

  7. Reactor Physics

    International Nuclear Information System (INIS)

    SCK-CEN's Reactor Physics and MYRRHA Department offers expertise in various areas of reactor physics, in particular in neutron and gamma calculations, reactor dosimetry, reactor operation and control, reactor code benchmarking and reactor safety calculations. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 materials testing reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2001 are summarised

  8. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A

    2001-04-01

    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised.

  9. Analysis of the non-cylindrical GA-4 and GA-9 spent fuel casks

    International Nuclear Information System (INIS)

    DOE's Office of Civilian Radioactive Waste Management (OCRWM) has awarded General Atomics (GA) a contract to develop the GA-4 and GA-9 legal weight truck (LWT) transportation system to transport pressurized-water-reactor (PWR) and boiling-water-reactor (BWR) spent fuels. The GA-4 and GA-9 Casks maximize cargo capacity while complying with the weight limits imposed on legal weight truck transport. These casks will carry up to 4 PWR or 9 BWR spent fuel assemblies, a capacity four times greater than comparable existing designs. The approach to the structural analysis of a non-cylindrical cross-section differs from a cylindrical design. These differences include: More orientations are evaluated for impact analyses; the structural analyses are more complex; and applicable criteria are more conservative and some require additional development. GA's structural analyses of the GA-4 and GA-9 Casks address each of these analytical differences, resulting in casks that meet the criteria imposed by applicable regulatory guides and the ASME Code. When necessary, we have confirmed our analytical approach with component testing. GA will obtain further confirmation during model testing in 1990. 2 refs., 7 figs

  10. Reactor control rod

    International Nuclear Information System (INIS)

    Object: To enable quick descent of a control rod body even when some relative phase deviation between upper drive means and wrapper tube is produced, while permitting a coolant to effectively flow into a protective tube irrespective of the position of the control rod body. Structure: In a control rod used for a nuclear reactor such as a fast breeder, an orifice which dispenses with a cylindrical guide tube and has a greater inner diameter than the outer diameter of the protective tube of the control rod body is provided on the inner side of a wrapper tube, thus permitting smooth operation of the control rod body and also permitting the coolant to effectively flow into the protective tube irrespective of the control rod body. (Horiuchi, T.)

  11. Direct Observation of a Semi-Bare Electron Coulomb Field Recover

    CERN Document Server

    Naumenko, G; Shevelev, M

    2011-01-01

    The problem of "semi-bare electron" was first considered in frame of quantum electrodynamics by E.L. Feinberg in 1980. In theory in frame of classical electrodynamics this problem was touched on in articles of N.F. Shul'ga and X. Artru. In 2008 the experimental investigations of this phenomenon in millimeter wavelength region were started by the group of scientists, including authors of this article. Used technique allowed us to study this effect in macroscopic mode. In this paper we present the results of direct observation of a semi-bare electron coulomb field recovery. The semi-bare state was obtained by passing of electron beam through the hole in a conductive screen. Measured spatial distribution of electromagnetic field shows the process of recover of the electron coulomb field, which is followed by a forward radiation. The experiments were performed on the relativistic electron beam of the microtron of Tomsk Polytechnic University.

  12. The Life Cycle of Bare Branch Families in China: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Quanbao Jiang

    2013-01-01

    Full Text Available China is characterized by a large number of men who are unable to marry, often referred to as “bare branches.” In this paper, we define the bare branch family and divide its life cycle into three stages: the unmarried co-resident with both parents, co-resident with a surviving parent, and living alone. As the childbearing age of parents increases, the age of a bare branch at the death of his parents decreases, and the duration of his living alone lengthens. An increase in the mother’s childbearing age, holding that of the father constant, shortens the stage of co-residence with both parents, and lengthens the stage of living alone.

  13. The COOLOCE experiments investigating the dryout power in debris beds of heap-like and cylindrical geometries

    Energy Technology Data Exchange (ETDEWEB)

    Takasuo, Eveliina, E-mail: eveliina.takasuo@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Espoo (Finland); Holmstroem, Stefan; Kinnunen, Tuomo; Pankakoski, Pekka H. [VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Espoo (Finland)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We investigate the effect of geometry on the coolability of porous core debris beds. Black-Right-Pointing-Pointer Dryout power is measured for a heap-like (conical) and a cylindrical debris bed. Black-Right-Pointing-Pointer The coolability of the cylindrical bed is better due to the lower height of the configuration. - Abstract: The COOLOCE test facility has been used for experimental investigations of the coolability of porous core debris beds with different geometries. The main objective of the experiments was to compare the dryout behavior of conical (heap-like) and top-flooded cylindrical (evenly distributed) debris bed configurations in order to investigate the effect of geometry on the coolability of the debris bed. The experimental debris beds simulate the possible outcomes of melt discharge from the reactor pressure vessel and the formation of a core debris bed in a deep water pool during a severe accident. The results suggest that if the two debris bed configurations have equal height, the coolability of the conical bed is improved compared to the cylindrical bed due to the multi-dimensional infiltration of water through the surface of the cone. However, in case the conical and cylindrical debris beds have equal diameter and volume, the dryout power density of the conical configuration is lower than that of the cylindrical configuration by approximately 50%. This is due to the greater height of the conical configuration which leads to increased heat flux in the upper parts of the conical debris bed. According to the present results, the effect of the increased debris bed height is greater than the effect of multi-dimensional flooding. Simulations show the differences between the two-phase flow behavior of the two geometries, and the resulting difference in dryout development.

  14. The COOLOCE experiments investigating the dryout power in debris beds of heap-like and cylindrical geometries

    International Nuclear Information System (INIS)

    Highlights: ► We investigate the effect of geometry on the coolability of porous core debris beds. ► Dryout power is measured for a heap-like (conical) and a cylindrical debris bed. ► The coolability of the cylindrical bed is better due to the lower height of the configuration. - Abstract: The COOLOCE test facility has been used for experimental investigations of the coolability of porous core debris beds with different geometries. The main objective of the experiments was to compare the dryout behavior of conical (heap-like) and top-flooded cylindrical (evenly distributed) debris bed configurations in order to investigate the effect of geometry on the coolability of the debris bed. The experimental debris beds simulate the possible outcomes of melt discharge from the reactor pressure vessel and the formation of a core debris bed in a deep water pool during a severe accident. The results suggest that if the two debris bed configurations have equal height, the coolability of the conical bed is improved compared to the cylindrical bed due to the multi-dimensional infiltration of water through the surface of the cone. However, in case the conical and cylindrical debris beds have equal diameter and volume, the dryout power density of the conical configuration is lower than that of the cylindrical configuration by approximately 50%. This is due to the greater height of the conical configuration which leads to increased heat flux in the upper parts of the conical debris bed. According to the present results, the effect of the increased debris bed height is greater than the effect of multi-dimensional flooding. Simulations show the differences between the two-phase flow behavior of the two geometries, and the resulting difference in dryout development.

  15. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  16. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    2013-01-01

    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  17. Settling of a cylindrical particle in a stagnant fluid

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Rosendahl, Lasse; Yin, Chungen;

    2007-01-01

    The objective of this work is to collect data and develop models for cylindrical particles which could be used in numerical multiphase flow modeling. Trajectories of cylindrical particles settling in stagnant water are filmed from two directions in order to derive detailed information on their...

  18. Ingestion of six cylindrical and four button batteries

    DEFF Research Database (Denmark)

    Nielsen, Simon U; Rasmussen, Morten; Hoegberg, Lotte C G

    2010-01-01

    We report a suicidal ingestion of six cylindrical and four button batteries, in combination with overdosed prescription medicine and smoking of cannabis.......We report a suicidal ingestion of six cylindrical and four button batteries, in combination with overdosed prescription medicine and smoking of cannabis....

  19. Hyperthermia of cylindrical biotissue samples by microwave electromagnetic radiation

    Science.gov (United States)

    Shul'Man, Z. P.; Slepyan, G. Ya.; Popkova, T. L.; Makhanyok, A. A.

    1998-03-01

    Consideration is given to the interaction of plane and cylindrical electromagnetic waves with layered cylindrical biotissue. Space distributions of the power density of heat loss are calculated and analyzed. The influence of biotissue inhomogeneities (arteries, veins) on electromagnetic heating is evaluated. The results reported can be used for hyperthermia of biological objects in oncology.

  20. Criticality analysis for weapon disassembly at the Pantex Plant - part I: Bare pits

    Energy Technology Data Exchange (ETDEWEB)

    Knief, R.A. [Ogden Environmental & Energy Services, Albuquerque, NM (United States)

    1997-06-01

    This paper briefly describes criticality investigations for weapon assembly and dismantlement at the Pantex Plant. Results are summarized for calculations performed for safety analyses, radiological hazards assessments, and a study to justify the criticality alarm exemption. Pits and pits in containers were modeled in their most reactive configuration. Criticality calculations were performed with the KENO and MCNP code packages. Configurations involving bare pits were subcritical by a substantial amount even with very conservative model assumptions. Thus, it is concluded that a critical configuration involving the bare pits is not credible.

  1. Criticality analysis for weapon disassembly at the Pantex Plant - part I: Bare pits

    International Nuclear Information System (INIS)

    This paper briefly describes criticality investigations for weapon assembly and dismantlement at the Pantex Plant. Results are summarized for calculations performed for safety analyses, radiological hazards assessments, and a study to justify the criticality alarm exemption. Pits and pits in containers were modeled in their most reactive configuration. Criticality calculations were performed with the KENO and MCNP code packages. Configurations involving bare pits were subcritical by a substantial amount even with very conservative model assumptions. Thus, it is concluded that a critical configuration involving the bare pits is not credible

  2. A proposed bare-tether experiment on board a sounding rocket

    OpenAIRE

    Fujii, Hironori A.; OYAMA, Koichiro; Sasaki, Susumu; Yamagiwa, Yoshiki; 藤井 裕矩; 小山 孝一郎; 佐々木 進; 山極 芳樹; Cho, Mengu; Sanmartin, Juan R.; Charro, Mario; VanderHeide, Erick J.; Kruijff, Michiel; Lebreton, Jean-Pierre

    2005-01-01

    A sounding rocket experiment is proposed to carry out two experiments by the conductive bare-tether; (1) the test of the OML (Orbital-Motion-Limited) theory to collect electron, and (2) the test of techniques to determine (neutral) density profile in critical E-layer. The main driver of the mission is provide a space tether technology experiment in Low-Earth-Orbit (LEO) deploying a long tape tether in space and verify the performance of the bare electrodynamic tape tether. The sounding rocket...

  3. Preliminary design of a spherical breed/burn reactor

    International Nuclear Information System (INIS)

    A breed/burn reactor (BBR) is a reactor that through transmutation process can burn depleted uranium (or other fertile material as thorium) with only a small amount of fissile material. The advantages of BBR over other type of nuclear reactors are wide, taking into account its long life operation without refueling. In this paper we present the simulation results done with MCNPX code and JEFF-3.1 cross sections library at 1200 K. The purpose of this study is to compare two different types of BBR: a spherical core and a cylindrical core, with the same nuclear fuel in both reactors. We found that both reactors maintained a supercritical state during 4500 days (12.3 years) without refueling. The plutonium production was achieved along the reactor in both cases. We also find that the spherical reactor operated as a stationary wave reactor, where the neutron flux uniformly increases in the sphere along the breeding zone with time, meanwhile the cylindrical reactor operated as a traveling wave reactor where neutron flux propagates as a wave in the cylinder along burnup. Further analysis will include Th-U fuel cycles and a more detailed model. (author)

  4. Consumption of the electric power inside silent discharge reactors

    Energy Technology Data Exchange (ETDEWEB)

    Yehia, Ashraf, E-mail: yehia30161@yahoo.com [Department of Physics, Faculty of Science, Assiut University, Assiut 71516, Arab Republic of Egypt and Department of Physics, College of Science and Humanitarian Studies at Alkharj, Salman bin Abdulaziz University, P.O. Box 83, Alkharj 11942 (Saudi Arabia)

    2015-01-15

    An experimental study was made in this paper to investigate the relation between the places of the dielectric barriers, which cover the surfaces of the electrodes in the coaxial cylindrical reactors, and the rate of change of the electric power that is consumed in forming silent discharges. Therefore, silent discharges have been formed inside three coaxial cylindrical reactors. The dielectric barriers in these reactors were pasted on both the internal surface of the outer electrode in the first reactor and the external surface of the inner electrode in the second reactor as well as the surfaces of the two electrodes in the third reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at normal temperature and pressure, in parallel with the application of a sinusoidal ac voltage between the electrodes of the reactor. The electric power consumed in forming the silent discharges inside the three reactors was measured as a function of the ac peak voltage. The validity of the experimental results was investigated by applying Manley's equation on the same discharge conditions. The results have shown that the rate of consumption of the electric power relative to the ac peak voltage per unit width of the discharge gap improves by a ratio of either 26.8% or 80% or 128% depending on the places of the dielectric barriers that cover the surfaces of the electrodes inside the three reactors.

  5. Moving-ring field-reversed mirror reactor concept

    International Nuclear Information System (INIS)

    The Moving-Ring Field-Reversed Mirror Reactor (MRFRMR) concept envisions production of electric power by burning magnetically field-reversed rings of fusion fuel which are translated continuously down the bore of a straight, cylindrical reactor burner chamber. Our interest in this reactor scheme arises from its potential design simplicity and the hope that it might be piloted in small size (50 to 100 MW(e)). This reactor has been evaluated only on a preliminary basis thus far and much of the following discussion is founded on the results of that first evaluation

  6. Preliminary design of a Binary Breeder Reactor; Diseno preliminar de un reactor esferico de quema/cria

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, E. Y.; Francois, J. L.; Lopez S, R. C., E-mail: eliasgarcerv@hotmail.com [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac No. 8532, 62550 Jiutepec, Morelos (Mexico)

    2014-10-15

    A binary breeder reactor (BBR) is a reactor that by means of the transmutation and fission process can operates through the depleted uranium burning with a small quantity of fissile material. The advantages of a BBR with relation to other nuclear reactor types are numerous, taking into account their capacity to operate for a long time without requiring fuel reload or re-arrangement. In this work four different simulations are shown carried out with the MCNPX code with libraries Jeff-3.1 to 1200 K. The objective of this study is to compare two different models of BBR: a spherical reactor and a cylindrical one, using two fuel cycles for each one of them (U-Pu and Th-U) and different reflectors for the two different geometries. For all the models a super-criticality state was obtained at least 10.9 years without carrying out some fuel re-arrangement or reload. The plutonium-239 production was achieved in the models where natural uranium was used in the breeding area, while the production of uranium-233 was observed in the cases where thorium was used in the fertile area. Finally, a behavior of stationary wave reactor was observed inside the models of spherical reactor when contemplating the power uniform increment in the breeding area, while inside the cylindrical models was observed the behavior of a traveling wave reactor when registering the displacement of the burnt wave along the cylindrical model. (Author)

  7. Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Frederick H. [Argonne National Laboratory; Jacobson, Norman H.

    1968-09-01

    This booklet discusses research reactors - reactors designed to provide a source of neutrons and/or gamma radiation for research, or to aid in the investigation of the effects of radiation on any type of material.

  8. Cylindrical Josephson junctions in magnetic fields

    International Nuclear Information System (INIS)

    The radial Josephson current I/sub J/ between co-axial cylinders was measured as a function of axial and azimuthal magnetic fields. The junctions were of two types: 0.25 mm diameter Nb-oxide-Sn single junctions and 0.25 mm film diameter Nb-oxide-Sn film double junctions. The Sn film of the single junctions was 160 nm or 200 nm. The Sn films of the double junctions were both either 155 nm or 230 nm. For a pair of cylinders I/sub J/ is zero except when both members are in the same fluxoid quantum state. When I/sub J/not equal to O, the relative phase is independent of aximuthal angle theta. In all measurements the cylinders were in fluxoid state zero. There was a critical value of axial field B/sub s/ which destroyed the Josephson coupling for each junction. This critical field is smallest for the outer tin junction of the double junction. It depends upon geometry and film thickness but is independent of the value of I/sub J/. The calculated value of the Gibbs function per unit volume of the tin films is, however, nearly the same for all junctions at their respective critical fields. Th Josephson current for the 160 nm Sn film single cylindrical junction was measured as a function of axial field B/sub z/ and azimuthal field B/sub theta/. When the axial field was zero the Josephson current as a function of azimuthal field showed the Fraunhofer like pattern of a flat junction in a magnetic field. As the axial field was increased, the central lobe of the Fraunhofer pattern decreased and disappeared at the critical field leaving the side lobes broadened. It is well known that a Josephson junction may switch to the voltage state at any current less than the maximum Josephson current. For some cylindrical junctions the switching currents are not continuously distributed but discrete with certain values occurring repeatedly. This observation is not understood

  9. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  10. Converging cylindrical shocks in ideal magnetohydrodynamics

    International Nuclear Information System (INIS)

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ0/p0) I/(2 π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  11. Neutronics and thermal hydraulics modelling of the Harwell Materials Testing Reactors DIDO and PLUTO

    International Nuclear Information System (INIS)

    A detailed 2-D cylindrical diffusion theory neutronics model is presented for the Harwell reactors DIDO and PLUTO, based on the WIMS-E program. The model for these highly asymmetric reactors allows for the presence of the various control systems, experimental rigs and fuel burnup. Comparisons made with measurements of burnup and of radial and axial flux distributions validate the approach. (author)

  12. Research reactors

    International Nuclear Information System (INIS)

    This article proposes an overview of research reactors, i.e. nuclear reactors of less than 100 MW. Generally, these reactors are used as neutron generators for basic research in matter sciences and for technological research as a support to power reactors. The author proposes an overview of the general design of research reactors in terms of core size, of number of fissions, of neutron flow, of neutron space distribution. He outlines that this design is a compromise between a compact enough core, a sufficient experiment volume, and high enough power densities without affecting neutron performance or its experimental use. The author evokes the safety framework (same regulations as for power reactors, more constraining measures after Fukushima, international bodies). He presents the main characteristics and operation of the two families which represent almost all research reactors; firstly, heavy water reactors (photos, drawings and figures illustrate different examples); and secondly light water moderated and cooled reactors with a distinction between open core pool reactors like Melusine and Triton, pool reactors with containment, experimental fast breeder reactors (Rapsodie, the Russian BOR 60, the Chinese CEFR). The author describes the main uses of research reactors: basic research, applied and technological research, safety tests, production of radio-isotopes for medicine and industry, analysis of elements present under the form of traces at very low concentrations, non destructive testing, doping of silicon mono-crystalline ingots. The author then discusses the relationship between research reactors and non proliferation, and finally evokes perspectives (decrease of the number of research reactors in the world, the Jules Horowitz project)

  13. Introducing the Notion of Bare and Effective Mass via Newton's Second Law of Motion

    Science.gov (United States)

    Pinto, Marcus Benghi

    2007-01-01

    The concepts of bare and effective mass are widely used within modern physics. Their meaning is discussed in advanced undergraduate and graduate courses such as solid state physics, nuclear physics and quantum field theory. Here I discuss how these concepts may be introduced together with the discussion of Newton's second law of motion. The…

  14. Bare Pedagogy and the Scourge of Neoliberalism: Rethinking Higher Education as a Democratic Public Sphere

    Science.gov (United States)

    Giroux, Henry A.

    2010-01-01

    A new form of bare pedagogy is emerging in higher education focused on market-driven competitiveness and even militaristic goal-setting, while critical pedagogy, with its emphasis on the hard work of critical analysis, moral judgments, and social responsibility (critical pedagogy that goes to the very heart of what it means to address real…

  15. Hypertrophic osteoarthropathy in a young child with cytomegalovirus pneumonia and the bare lymphocyte syndrome

    International Nuclear Information System (INIS)

    A case of hypertrophic osteoarthropathy is reported in a 3-year-old Turkish girl. She had combined immunodeficiency, later shown to be the Bare Lymphocyte syndrome, and chronic pneumonia. Lung biopsy showed cytomegalovirus. The child developed painful elbow and knee joints and hypertrophic osteoarthropathy was demonstrated radiologically. (orig.)

  16. Electroless deposition of palladium at bare and templated liquid/liquid interfaces.

    Science.gov (United States)

    Dryfe, Robert A W; Simm, Andrew O; Kralj, Brett

    2003-10-29

    A simple, electroless approach to metallize the liquid/liquid interface is reported. The method is illustrated with the deposition of Pd at the bare water/1,2-dichloroethane interface, and for the "templated" deposition of Pd within the 100 nm diameter pores of gamma-alumina membranes. PMID:14570460

  17. Phospholipid bilayer formation at a bare Si surface: a time-resolved neutron reflectivity study

    DEFF Research Database (Denmark)

    Gutberlet, T.; Steitz, R.; Fragneto, G.; Klösgen-Buchkremer, Beate Maria

    2004-01-01

    Neutron reflectivity was applied to monitor in situ the adsorption of small unilamellar phospholipid vesicles on a solid bare hydrophilic Si interface. The obtained reflectivity curves are consistent with the rupture and fusion model for the adsorption of phosphatidylcholine vesicles to solid...... as adsorption and penetration of peptides and proteins towards the supported bilayer at high resolution....

  18. Reactor physics and reactor computations

    International Nuclear Information System (INIS)

    Mathematical methods and computer calculations for nuclear and thermonuclear reactor kinetics, reactor physics, neutron transport theory, core lattice parameters, waste treatment by transmutation, breeding, nuclear and thermonuclear fuels are the main interests of the conference

  19. Research reactors

    International Nuclear Information System (INIS)

    There are currently 284 research reactors in operation, and 12 under construction around the world. Of the operating reactors, nearly two-thirds are used exclusively for research, and the rest for a variety of purposes, including training, testing, and critical assembly. For more than 50 years, research reactor programs have contributed greatly to the scientific and educational communities. Today, six of the world's research reactors are being shut down, three of which are in the USA. With government budget constraints and the growing proliferation concerns surrounding the use of highly enriched uranium in some of these reactors, the future of nuclear research could be impacted

  20. Reactor container

    International Nuclear Information System (INIS)

    Object: To provide a jet and missile protective wall of a configuration being inflated toward the center of a reactor container on the inside of a body of the reactor container disposed within a biological shield wall to thereby increase safety of the reactor container. Structure: A jet and missile protective wall comprised of curved surfaces internally formed with a plurality of arch inflations filled with concrete between inner and outer iron plates and shape steel beam is provided between a reactor container surrounded by a biological shield wall and a thermal shield wall surrounding the reactor pressure vessel, and an adiabatic heat insulating material is filled in space therebetween. (Yoshino, Y.)

  1. Functional evolution of quantum cylindrical waves

    CERN Document Server

    Cho, D H J; Cho, Demian H.J.; Varadarajan, Madhavan

    2006-01-01

    Kucha{\\v{r}} showed that the quantum dynamics of (1 polarization) cylindrical wave solutions to vacuum general relativity is determined by that of a free axially-symmetric scalar field along arbitrary axially-symmetric foliations of a fixed flat 2+1 dimensional spacetime. We investigate if such a dynamics can be defined {\\em unitarily} within the standard Fock space quantization of the scalar field. Evolution between two arbitrary slices of an arbitrary foliation of the flat spacetime can be built out of a restricted class of evolutions (and their inverses). The restricted evolution is from an initial flat slice to an arbitrary (in general, curved) slice of the flat spacetime and can be decomposed into (i) `time' evolution in which the spatial Minkowskian coordinates serve as spatial coordinates on the initial and the final slice, followed by (ii) the action of a spatial diffeomorphism of the final slice on the data obtained from (i). We show that although the functional evolution of (i) is unitarily implemen...

  2. Rotating cylindrical wormholes and energy conditions

    Science.gov (United States)

    Bronnikov, K. A.; Krechet, V. G.

    2016-01-01

    We seek wormholes among rotating cylindrically symmetric configurations in general relativity. Exact wormhole solutions are presented with such sources of gravity as a massless scalar field, a cosmological constant, and a scalar field with an exponential potential. However, none of these solutions are asymptotically flat, which excludes the existence of wormhole entrances as local objects in our Universe. To overcome this difficulty, we try to build configurations with flat asymptotic regions using the cut-and-paste procedure: on both sides of the throat, a wormhole solution is matched to a properly chosen region of flat space-time at some surfaces Σ- and Σ+. It is shown, however, that if the source of gravity in the throat region is a scalar field with an arbitrary potential, then one or both thin shells appearing on Σ- and Σ+ inevitably violate the null energy condition. Thus, although rotating wormhole solutions are easily found without exotic matter, such matter is still necessary for obtaining asymptotic flatness.

  3. Technology Selections for Cylindrical Compact Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Phillips

    2010-10-01

    A variety of process approaches are available and have been used historically for manufacture of cylindrical fuel compacts. The jet milling, fluid bed overcoating, and hot press compacting approach being adopted in the U.S. AGR Fuel Development Program for scale-up of the compacting process involves significant paradigm shifts from historical approaches. New methods are being pursued because of distinct advantages in simplicity, yield, and elimination of process mixed waste. Recent advances in jet milling technology allow simplified dry matrix powder preparation. The matrix preparation method is well matched with patented fluid bed powder overcoating technology recently developed for the pharmaceutical industry and directly usable for high density fuel particle matrix overcoating. High density overcoating places fuel particles as close as possible to their final position in the compact and is matched with hot press compacting which fully fluidizes matrix resin to achieve die fill at low compacting pressures and without matrix end caps. Overall the revised methodology provides a simpler process that should provide very high yields, improve homogeneity, further reduce defect fractions, eliminate intermediate grading and QC steps, and allow further increases in fuel packing fractions.

  4. Technology Selections for Cylindrical Compact Fabrication

    International Nuclear Information System (INIS)

    A variety of process approaches are available and have been used historically for manufacture of cylindrical fuel compacts. The jet milling, fluid bed overcoating, and hot press compacting approach being adopted in the U.S. AGR Fuel Development Program for scale-up of the compacting process involves significant paradigm shifts from historical approaches. New methods are being pursued because of distinct advantages in simplicity, yield, and elimination of process mixed waste. Recent advances in jet milling technology allow simplified dry matrix powder preparation. The matrix preparation method is well matched with patented fluid bed powder overcoating technology recently developed for the pharmaceutical industry and directly usable for high density fuel particle matrix overcoating. High density overcoating places fuel particles as close as possible to their final position in the compact and is matched with hot press compacting which fully fluidizes matrix resin to achieve die fill at low compacting pressures and without matrix end caps. Overall the revised methodology provides a simpler process that should provide very high yields, improve homogeneity, further reduce defect fractions, eliminate intermediate grading and QC steps, and allow further increases in fuel packing fractions.

  5. Large area cylindrical silicon drift detector

    International Nuclear Information System (INIS)

    An advanced silicon drift detector, a large area cylindrical drift detector, was designed, produced, tested and installed in the NA45 experiment. The active area of the detector is practically the total area of a 3 inch diameter wafer. Signal electrons created in the silicon detector by fast charged particles drift radially outside toward an array of 360 anodes located on the periphery of the detector. The drift time measures the radial coordinate of the particle's intersection; the charge sharing between anodes measures the azimuthal coordinate. The detector provides unambiguous pairs of r,φ coordinates for events with multiplicities up to several hundred. Its use in the experiment aims at a position resolution of 20 μm (rms) in each direction giving about 2 · 106 two-dimensional elements. There is a small hole in the center of the detector to allow the passage of the noninteracting particle beam. The longest drift distance is about 3 cm. The nominal value of the drift field is 500 V/cm resulting in a maximum drift time of 4 μs

  6. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.

  7. Large area cylindrical silicon drift detector

    International Nuclear Information System (INIS)

    This paper reports on an advanced silicone drift detector, a large area cylindrical drift detector that was designed, produced, tested and installed in the Na45 experiment. The active area of the detector is practically the total area of a 3 inch diameter wafer. Signal electrons created in the silicon detector by fast charged particles drift radially outside toward an array of 360 anodes located on the periphery of the detector. The drift time measures the radial coordinate of the particle's intersection; the charge sharing between anodes measures the azimuthal coordinate. The detector provides unambiguous pairs of r, φ coordinates for events with multiplicities up to several hundred. Its use in the experiment aims at a position resolution of 20 μm (rms) in each direction giving about 2 · 106 two-dimensional elements. There is a small hole in the center of the detector to allow the passage of the noninteracting particle beam. The longest drift distance is about 3 cm. The nominal value of the drift field is 500 V/cm resulting in a maximum drift time of 4 μs

  8. Surface tension and long range corrections of cylindrical interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bourasseau, E. [CEA/DAM DIF, F-91297 Arpajon Cedex (France); Malfreyt, P. [Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Ghoufi, A., E-mail: aziz.ghoufi@univ-rennes1.fr [Institut de Physique de Rennes, UMR 6251 CNRS, Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes (France)

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  9. Surface tension and long range corrections of cylindrical interfaces

    International Nuclear Information System (INIS)

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials

  10. Pressurized water nuclear reactor system with hot leg vortex mitigator

    Science.gov (United States)

    Lau, Louis K. S.

    1990-01-01

    A pressurized water nuclear reactor system includes a vortex mitigator in the form of a cylindrical conduit between the hot leg conduit and a first section of residual heat removal conduit, which conduit leads to a pump and a second section of residual heat removal conduit leading back to the reactor pressure vessel. The cylindrical conduit is of such a size that where the hot leg has an inner diameter D.sub.1, the first section has an inner diameter D.sub.2, and the cylindrical conduit or step nozzle has a length L and an inner diameter of D.sub.3 ; D.sub.3 /D.sub.1 is at least 0.55, D.sub.2 is at least 1.9, and L/D.sub.3 is at least 1.44, whereby cavitation of the pump by a vortex formed in the hot leg is prevented.

  11. The contribution of vegetation cover and bare soil to pixel reflectance in an arid ecosystem

    Science.gov (United States)

    Steele, C. M.; Smith, A.; Campanella, A.; Rango, A.

    2008-12-01

    The heterogeneity of vegetation and soils in arid and semi-arid environments complicates the analysis of medium spatial resolution remotely sensed imagery. A single pixel may contain several different types of vegetation, as well as a sizeable proportion of bare soil. We have used linear mixture modeling to explore the contribution of vegetation cover and bare soil to pixel reflectance. In October, 2006, aerial imagery (0.25 m spatial resolution) was acquired for our study sites in the Jornada Experimental Range, southern New Mexico. Imagery was also acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for June and November, 2006. These data corresponded with pre- and post monsoon conditions. Object-based feature extraction was used to classify the aerial imagery to shrub, grass and bare ground cover classes. Percent cover was then calculated for each cover class. Visible-near-infrared and shortwave infrared ASTER reflectance data from both dates were combined into a single 18-band dataset (30 m spatial resolution). A vector overlay from the classification results of the aerial imagery was used to define pure endmember pixels in the ASTER imagery. Estimates of the proportions of shrub, grass and bare ground cover from the linear mixture modeling approach were compared with cover calculated using feature extraction from the aerial imagery. The results indicate that reflectance in ASTER pixels is likely to be a linear combination of the cover proportions of the three main cover types (shrubs, grass, bare ground). However, noticeable outliers in the relationship between cover calculated from each method, indicate there may be other variables that affect the accuracy with which we can estimate cover using linear mixture modeling.

  12. New measurement of $\\rm S_{bare}(E)$ factor of the d(d,p)t reaction at astrophysical energies via the Trojan-horse method

    CERN Document Server

    Li, Chengbo; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C; Tumino, A; Pizzone, R G; Lamia, L

    2015-01-01

    The study of d(d,p)t reaction is very important for the nucleosynthesis in both standard Big Bang and stellar evolution, as well as for the future fusion reactor planning of energy production. The d(d,p)t bare nucleus astrophysical S(E) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan horse method applied to the quasi-free process $\\rm {}^2H({}^6Li,pt){}^4He$ induced at the lithium beam energy of 9.5 MeV, which is closer to the zero quasi-free energy point, in CIAE HI-13 tandem accelerator laboratory. An accurate analysis leads to the determination of the d(d,p)t $\\rm S(E)$ factor $\\rm S_{bare}(0)=56.7 \\pm 2.0 keV*b$ and of the corresponding electron screening potential $\\rm U_e = 13.2 \\pm 4.3 eV$. In addition, this work also gives an updated test for the Trojan horse nucleus invariance comparing with previous indirect investigations using $\\rm {}^3He=(d+p)$ breakup.

  13. Liquid metal cooled fast breeder nuclear reactor

    International Nuclear Information System (INIS)

    A liquid metal cooled fast breeder nuclear reactor has a core comprising a plurality of fuel assemblies supported on a diagrid and submerged in a pool of liquid metal coolant within a containment vessel, the diagrid being of triple component construction and formed of a short cylindrical plenum mounted on a conical undershell and loosely embraced by a fuel store carrier. The plenum merely distributes coolant through the fuel assemblies, the load of the assemblies being carried by the undershell by means of struts which penetrate the plenum. The reactor core, fuel store carrier and undershell provide secondary containment for the plenum. (UK)

  14. Study of selected turbulent models for supercritical water heat transfer in vertical bare tubes using CFD code FLUENT-12

    International Nuclear Information System (INIS)

    Many of the available empirical correlations existing today cannot predict closely the effects of the heat transfer phenomena within the pseudocritical region, and some do not predict well enough heat transfer coefficients even outside of this region. In this study, the Computational Fluid Dynamics (CFD) code FLUENT-12 is used with associated software such as Gambit and NIST REFPROP to predict the Heat Transfer Coefficient and corresponding wall temperature profiles inside circular tubes cooled with SuperCritical Water (SCW), and to compare them with experimental data and various empirical correlations. In this paper, a numerical study of heat transfer to SCW flowing upwards in vertical bare tubes using the CFD-code FLUENT-12 is presented for comparison to 1-D models. A large dataset was collected within conditions similar to those of proposed SuperCritical Water-cooled Reactors (SCWRs) at the Institute for Physics and Power Engineering in Obninsk, Russia. This dataset includes 80 runs in a 4-m long, 10-mm ID vertical bare tube within a wide range of operating parameters including pressure at about 24 MPa, inlet temperatures from 320 to 350°C, mass flux ranges from 200 to 1500 kg/m2s and heat fluxes up to 1250 kW/m2. Wall and bulk-fluid temperatures measured along the 4-m heated length test section were below, at, or above the pseudocritical point. Further analysis of the individual heat-transfer regimes was conducted using an axisymmetric 2-D model of a tube with 10,000 nodes along the heated length. Wall temperatures and heat transfer coefficients were analysed for 1-m sections at a time to select the best model for each region (below, within and beyond the pseudocritical region), and to neutralize effects of the rest of the tube on that region. Two turbulent models were used in the process: k-ε and k-ω, with many variations in the sub-model parameters such as viscous heating, thermal effects, and low-Reynolds number correction. The results show a good fit

  15. Metallic post-array loaded cylindrical dielectric resonator antenna

    Directory of Open Access Journals (Sweden)

    Byeong-Yong Park

    2016-01-01

    Full Text Available An investigation of a novel cylindrical dielectric resonator antenna (DRA configuration has been carried out. It is shown that two resonances including the full- and half-cylindrical HE(11δ-like modes can coexist simultaneously at different frequencies by placing a metallic post array in the resonator. Moreover, compared with the conventional HE(11δ mode cylindrical DRA having the same size, the proposed antenna operates in lower frequency band and shows improved bandwidth. The experimental results including the return loss and the radiation patterns are demonstrated.

  16. γ-ray self-absorption of cylindrical fissile material

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Yi; CHENG Yi-Ying; TIAN Dong-Feng; LU Fu-Quan; YANG Fu-Jia

    2005-01-01

    The self-absorption of γ-ray emitted from cylindrical fissile materials, such as 235U and 239Pu, does not possess spherical symmetry. The analytical formulae of self-absorption for γ-ray throughout the cylinder have been obtained. The intensity of γ-ray is a function of γ-ray outgoing directions and cylindrical configurations, accordingly one can acquire the information about geometrical configuration of cylindrical fissile materials through multi-location measurements. Further more, the method is given in this article. The result can be applied to the fissile material safeguard, such as nuclear monitoring and verifying.

  17. New cylindrical gravitational soliton waves and gravitational Faraday rotation

    CERN Document Server

    Tomizawa, Shinya

    2013-01-01

    In terms of gravitational solitons, we study gravitational non-linear effects of gravitational solitary waves such as Faraday rotation. Applying the Pomeransky's procedure for inverse scattering method, which has been recently used for constructing stationary black hole solutions in five dimensions to a cylindrical spacetime in four dimensions, we construct a new cylindrically symmetric soliton solution. This is the first example to be applied to the cylindrically symmetric case. In particular, we clarify the difference from the Tomimatsu's single soliton solution, which was constructed by the Belinsky-Zakharov's procedure.

  18. Prototype moving-ring reactor

    International Nuclear Information System (INIS)

    We have completed a design of the Prototype Moving-Ring Reactor. The fusion fuel is confined in current-carrying rings of magnetically-field-reversed plasma (Compact Toroids). The plasma rings, formed by a coaxial plasma gun, undergo adiabatic magnetic compression to ignition temperature while they are being injected into the reactor's burner section. The cylindrical burner chamber is divided into three burn stations. Separator coils and a slight axial guide field gradient are used to shuttle the ignited toroids rapidly from one burn station to the next, pausing for 1/3 of the total burn time at each station. D-T-3He ice pellets refuel the rings at a rate which maintains constant radiated power

  19. Sensitivity factor analysis using computer simulation for radon detection in cylindrical diffusion chambers with nuclear track detectors

    International Nuclear Information System (INIS)

    Sensitivity factor analysis for radon detection in cylindrical diffusion chambers was carried out using computer program developed in C language. Radon gas entering to cylindrical cup dosimeter decays registering alpha tracks on NTD film in the chamber. The processes following each radon decay such as progeny particle formation, progeny decay, diffusion through Brownian motion, surface deposition and track registration on NTDs complexities the scenario inside the diffusion chamber. This can be analysed in a better way using computer simulation. Present work involves development of program for analysis on partial sensitivity factor of radon in cup dosimeters. Random numbers are used for accounting the uncertainty in alpha particle emission points and directions of alpha emission. First part of the work involves analyses of fluence on bare detector and comparison with theoretical result. Then the variation in sensitivity factor is analyzed by putting angle constrain. Then different energy windows for countable alpha track registration on LR115 type detectors are considered and the results are presented. (author)

  20. Liquid-argon cylindrical pulsed ionization chamber

    International Nuclear Information System (INIS)

    A liquid-argon cylindrical ionization chamber with a working volume of 200 cm2 is described. The chamber anode is made of stainless steel in the form of a hollow cylinder 30 mm in diameter and 140 mm in length. A beryllium bronze wire in diameter of 0.1 mm and at a spacing of 1 mm is used for winding the chamber screen grid. The chamber cathode is a brass thin-walled cylinder having an internal diameter of 56 mm and a height of 156 mm. The cathode-grid gap is 10 mm, the cathode-case gap is 2 mm. A 0.5 l cooling bath filled with liquid nitrogen is used to refrigirate the chamber. The chamber is evacuated to about 10-5 mm Hg. The total concentration of electronegative impurities in argon does not exceed 6x10-9. Dependences of the chamber counting and amplitude responses, on the cathode voltage under irradiation with γ-quanta at energies of 0.898 MeV and 1.836 MeV are given. The value of the energy resolution was evaluated by differentiating the high-energy edge of the Compton spectrum. The total width at a peak half-height constitutes 5% for an electron energy of 1.612 MeV. To achieve better resolution of the chamber it is necessary to reduce preamplifier noises by three times, to increase the working gap of the chamber and decrease the grid-anode gap

  1. Velocity Inversion In Cylindrical Couette Gas Flows

    International Nuclear Information System (INIS)

    We investigate a power-law probability distribution function to describe the mean free path of rarefied gas molecules in non-planar geometries. A new curvature-dependent model is derived by taking into account the boundary-limiting effects on the molecular mean free path for surfaces with both convex and concave curvatures. In comparison to a planar wall, we find that the mean free path for a convex surface is higher at the wall and exhibits a sharper gradient within the Knudsen layer. In contrast, a concave wall exhibits a lower mean free path near the surface and the gradients in the Knudsen layer are shallower. The Navier-Stokes constitutive relations and velocity-slip boundary conditions are modified based on a power-law scaling to describe the mean free path, in accordance with the kinetic theory of gases, i.e. transport properties can be described in terms of the mean free path. Velocity profiles for isothermal cylindrical Couette flow are obtained using the power-law model. We demonstrate that our model is more accurate than the classical slip solution, especially in the transition regime, and we are able to capture important non-linear trends associated with the non-equilibrium physics of the Knudsen layer. In addition, we establish a new criterion for the critical accommodation coefficient that leads to the non-intuitive phenomena of velocity-inversion. Our results are compared with conventional hydrodynamic models and direct simulation Monte Carlo data. The power-law model predicts that the critical accommodation coefficient is significantly lower than that calculated using the classical slip solution and is in good agreement with available DSMC data. Our proposed constitutive scaling for non-planar surfaces is based on simple physical arguments and can be readily implemented in conventional fluid dynamics codes for arbitrary geometric configurations.

  2. Seismic response of flexible cylindrical tanks

    International Nuclear Information System (INIS)

    An experimental study of the seismic behavior of thin shell circular cylindrical liquid storage tanks is described. The investigation was planned to evaluate the adequacy of present methods of tank design, and was conducted using the Earthquake Simulator Facility of the University of California, Berkeley. The model tank considered in this paper was 6 ft high by 12 ft in diameter, and was welded from thin sheet aluminum to simulate a steel tank 36 feet in diameter. During testing the tank had an open top, held 60 inches of water, and was subjected to a time scaled El Centro (1940) earthquake, amplified to a peak acceleration of 0.5 g. Both base free and base fixed conditions were studied. Results of the experiments demonstrate that fluid pressures included both impulsive and convective components, and that the wave sloshing followed basic theory quite closely. But it also was apparent that the tank flexibility influenced the hydrodynamic pressures, as indicated by pressure amplification in the clamped tank, and by a total change of pressure history in the unclamped case. Significant out of round distortions of the tank were developed, of a three lobe form or the free base case and with four lobes in the fixed base case. Uplift of the tank base was closely related to the out-of-round deformation of the unanchored tank, whereas initial eccentricities apparently caused the section distortions in the anchored system. Stresses in the tank wall do not follow the expected pattern of response to overturning moment; instead they seem to be mainly associated with the section distortions. At present there is no analytical procedure for predicting these distortions

  3. The cylindrical condition and Einstein-Bergmann theory

    International Nuclear Information System (INIS)

    Recently work on unification of forces has centered on constructing higher-dimensional theories. Typically a higher-dimensional space is a direct product of a four-dimensional space with a compact space that has a high degree of symmetry. The idea of compactification was first proposed by Klein and later mathematically formalized by Einstein and Bergmann. The origin of compactification is based on the cylindrical condition proposed by Kaluza as a practical approximation. The cylindrical condition was used as an assumption by Klein. Later, based on some geometrical assumptions, the cylindrical condition was mathematically derived by Einstein and Bergmann. Kaluza's aim was undoubtedly to obtain some new physical aspect of gravitation and electricity by introducing a unitary field structure. It is shown that the Einstein-Bergmann theory implies that a rigorous cylindrical condition may not be compatible with Kaluza's theory

  4. Numerical analysis of cocurrent conical and cylindrical axial cyclone separators

    Science.gov (United States)

    Nor, M. A. M.; Al-Kayiem, H. H.; Lemma, T. A.

    2015-12-01

    Axial concurrent liquid-liquid separator is seen as an alternative unit to the traditional tangential counter current cyclone due to lower droplet break ups, turbulence and pressure drop. This paper presents the numerical analysis of a new conical axial cocurrent design along with a comparison to the cylindrical axial cocurrent type. The simulation was carried out using CFD technique in ANSYS-FLUENT software. The simulation results were validated by comparison with experimental data from literature, and mesh independency and quality were performed. The analysis indicates that the conical version achieves better separation performance compared to the cylindrical type. Simulation results indicate tangential velocity with 8% higher and axial velocity with 80% lower recirculation compared to the cylindrical type. Also, the flow visualization counters shows smaller recirculation region relative to the cylindrical unit. The proposed conical design seems more efficient and suits the crude/water separation in O&G industry.

  5. Second order focusing property of 210deg cylindrical energy analyzer

    International Nuclear Information System (INIS)

    It was confirmed experimentally that a 210deg cylindrical energy analyzer with drift spaces has second order focusing. The properties of the analyzer is deeply dependent on the fringing field around the entrance and exit of the cylinders. (author)

  6. Theory and modeling of cylindrical thermo-acoustic transduction

    Science.gov (United States)

    Tong, Lihong; Lim, C. W.; Zhao, Xiushao; Geng, Daxing

    2016-06-01

    Models both for solid and thinfilm-solid cylindrical thermo-acoustic transductions are proposed and the corresponding acoustic pressure solutions are obtained. The acoustic pressure for an individual carbon nanotube (CNT) as a function of input power is investigated analytically and it is verified by comparing with the published experimental data. Further numerical analysis on the acoustic pressure response and characteristics for varying input frequency and distance are also examined both for solid and thinfilm-solid cylindrical thermo-acoustic transductions. Through detailed theoretical and numerical studies on the acoustic pressure solution for thinfilm-solid cylindrical transduction, it is concluded that a solid with smaller thermal conductivity favors to improve the acoustic performance. In general, the proposed models are applicable to a variety of cylindrical thermo-acoustic devices performing in different gaseous media.

  7. A single-electron current in a cylindrical nanolayer

    International Nuclear Information System (INIS)

    The orbital current and the spin magnetic moment current of an electron in a cylindrical nanolayer are investigated. It is shown that under certain conditions, the main contribution to the total current is specified by the spin magnetic moment current

  8. Cylindrical Cardboard Model for a Rotating System in Special Relativity.

    Science.gov (United States)

    Noerdlinger, Peter D.

    1979-01-01

    Presents a cylindrical cardboard model that helps students at the graduate or undergraduate level to visualize the nature of simultaneity and the propagation of light in a rotating coordinate system. (HM)

  9. Singularity-free orthogonally-transitive cylindrical spacetimes

    CERN Document Server

    Fernández-Jambrina, L

    2009-01-01

    In this talk a previous theorem on geodesic completeness of diagonal cylindrical spacetimes will be generalized to cope with the nondiagonal case. A sufficient condition for such spacetimes to be causally geodesically complete will be given

  10. Nonsingularity in two-dimensional cylindrical invisible cloaks

    International Nuclear Information System (INIS)

    The method of designing electromagnetic invisible cloaks is usually based on the form-invariance of Maxwell's equations in coordinate transformation. The exterior boundary of a cylindrical invisible cloak is unchanged and the interior boundary is extended from that of a point to that of a cylindrical region in coordination transformation. This transformation process makes perfect cloaks, but it causes singularity in the constitutive material parameters of cloaks. This singularity makes the cloaks impossible to realize in practice. In order to remove this singularity, this paper sets a small cylindrical region replacing a point in the space transformation. The cylindrical region is so small that it does not affect the invisibility effects, but it can remove the singularity for material parameters. Full wave simulations based on the finite element method were used to verify the designed cloaks. (classical areas of phenomenology)

  11. Speckle size of light scattered from slightly rough cylindrical surfaces

    Science.gov (United States)

    Berlasso, Ricardo G.; Quintian, Fernando Perez; Rebollo, Maria A.; Gaggioli, Nestor G.; Brea, Luis Miguel Sanchez; Martinez, Eusebio Bernabeu

    2002-04-01

    This research is an extension of the optical method of quality control presented in a previous paper [Appl. Opt. 39, 5811 (2000)] to the case of slightly rough cylindrical surfaces. Applying the Kirchhoff scalar diffraction theory yields an analytical expression of the autocorrelation function of the intensity scattered from slightly rough cylindrical surfaces. This function, which is related to speckle size and shape, is shown to depend on the surface correlation length, unlike for plane surfaces for which the speckle depends on the illuminated area only. The theoretical expression is compared with that for the speckle produced by the light scattered from a cylindrical bearing and from various high-quality wires, showing that the method allows the correlation lengths of high-quality cylindrical surfaces to be determined.

  12. Response of an electrostatic probe for a right cylindrical spacer

    DEFF Research Database (Denmark)

    Rerup, T; Crichton, George C; McAllister, Iain Wilson

    1994-01-01

    During the last decade many experimental studies of surface charge phenomena have been undertaken employing right cylindrical spacers. Measurement of the surface charge was performed using small electrostatic field probes to scan across the dielectric surface. Charges are electrostatically induced...

  13. Self-exciting oscillation of free liquid surface by vertical cylindrical jet colliding with cylindrical structure

    International Nuclear Information System (INIS)

    Top entry type FBRs have free liquid surfaces in plural vessels. Free liquid surface is the boundary condition with very strong nonlinearity, and by the interference with high velocity flow, there is the possibility of causing various unstable phenomena. The oscillation of high temperature sodium liquid surface originates in its high thermal conductivity, and brings about fatigue to in-core structures by applying high thermal stress. In this research, by using the experimental setup of a simplified FBR, in which there are the cylindrical upper structure simulating core upper mechanism, free liquid surface and vertical cylindrical jet, the behavior of the liquid surface was examined. As the result, several kinds of the self-exciting oscillation of the liquid surface were observed. The experimental setup and the experimental method are explained. Two kinds of the observed natural oscillation modes of the liquid in a vessel are shown. The regions where respective modes arose and the change of dominant frequency due to flow velocity are reported. Respective modes and the similarity with already known phenomena are described. (K.I.)

  14. A Comparison of Bare-Metal and Drug-Eluting Stents for Off-Label Indications

    Science.gov (United States)

    Marroquin, Oscar C.; Selzer, Faith; Mulukutla, Suresh R.; Williams, David O.; Vlachos, Helen A.; Wilensky, Robert L.; Tanguay, Jean-François; Holper, Elizabeth M.; Abbott, J. Dawn; Lee, Joon S.; Smith, Conrad; Anderson, William D.; Kelsey, Sheryl F.; Kip, Kevin E.

    2009-01-01

    Background Recent reports suggest that off-label use of drug-eluting stents is associated with an increased incidence of adverse events. Whether the use of bare-metal stents would yield different results is unknown. Methods We analyzed data from 6551 patients in the National Heart, Lung, and Blood Institute Dynamic Registry according to whether they were treated with drug-eluting stents or bare-metal stents and whether use was standard or off-label. Patients were followed for 1 year for the occurrence of cardiovascular events and death. Off-label use was defined as use in restenotic lesions, lesions in a bypass graft, left main coronary artery disease, or ostial, bifurcated, or totally occluded lesions, as well as use in patients with a reference-vessel diameter of less than 2.5 mm or greater than 3.75 mm or a lesion length of more than 30 mm. Results Off-label use occurred in 54.7% of all patients with bare-metal stents and 48.7% of patients with drug-eluting stents. As compared with patients with bare-metal stents, patients with drug-eluting stents had a higher prevalence of diabetes, hypertension, renal disease, previous percutaneous coronary intervention and coronary-artery bypass grafting, and multivessel coronary artery disease. One year after intervention, however, there were no significant differences in the adjusted risk of death or myocardial infarction in patients with drug-eluting stents as compared with those with bare-metal stents, whereas the risk of repeat revascularization was significantly lower among patients with drug-eluting stents. Conclusions Among patients with off-label indications, the use of drug-eluting stents was not associated with an increased risk of death or myocardial infarction but was associated with a lower rate of repeat revascularization at 1 year, as compared with bare-metal stents. These findings support the use of drug-eluting stents for off-label indications. PMID:18216354

  15. The Swedish Zero Power Reactor R0

    International Nuclear Information System (INIS)

    The reactor R0 is a critical facility built for heavy water and natural uranium or fuel of low enrichment,, The first criticality was achieved September 25, 1959. During a first period of more than two years the R0 will be operated as a bare reactor in order to simplify interpretation of results. The reactor tank is 3. 2 m high and 2. 25 m in diameter. The fuel suspension system is quite flexible in order to facilitate fuel exchange and lattice variations. The temperature of the water can be varied between about 10 and 90 C by means of a heater and a cooler placed in the external circulating system. The instrumentation of the reactor has to meet the safety requirements not only during operation but also during rearrangements of the core in the shut-down state. Therefore, the shut-down state is always defined by a certain low 'safe' moderator level in the reactor tank. A number of safety rods are normally kept above the moderator ready for action. For manual or automatic control of the reactor power a specially designed piston pump is needed, by which the moderator level is varied. The pump speed is controlled from the reactor power error by means of a Ward-Leonard system. Moderator level measurement is made by means of a water gauge with an accuracy of ± 0. 1 mm

  16. The Swedish Zero Power Reactor R0

    Energy Technology Data Exchange (ETDEWEB)

    Landergaard, Olof; Cavallin, Kaj; Jonsson, Georg

    1961-05-15

    The reactor R0 is a critical facility built for heavy water and natural uranium or fuel of low enrichment,, The first criticality was achieved September 25, 1959. During a first period of more than two years the R0 will be operated as a bare reactor in order to simplify interpretation of results. The reactor tank is 3. 2 m high and 2. 25 m in diameter. The fuel suspension system is quite flexible in order to facilitate fuel exchange and lattice variations. The temperature of the water can be varied between about 10 and 90 C by means of a heater and a cooler placed in the external circulating system. The instrumentation of the reactor has to meet the safety requirements not only during operation but also during rearrangements of the core in the shut-down state. Therefore, the shut-down state is always defined by a certain low 'safe' moderator level in the reactor tank. A number of safety rods are normally kept above the moderator ready for action. For manual or automatic control of the reactor power a specially designed piston pump is needed, by which the moderator level is varied. The pump speed is controlled from the reactor power error by means of a Ward-Leonard system. Moderator level measurement is made by means of a water gauge with an accuracy of {+-} 0. 1 mm.

  17. Macrophage uptake of cylindrical microparticles investigated with correlative microscopy.

    OpenAIRE

    Tscheka, Clemens; Hittinger, Marius; Lehr, Claus-Michael; Schneider-Daum, Nicole; Schneider, Marc

    2015-01-01

    Cylindrical particles offer the opportunity to develop controlled and sustained release systems for the respiratory tract. One reason is that macrophages can phagocyte such particles only from either of the two ends. We investigated the uptake behaviour of murine alveolar macrophages incubated with elongated submicron-structured particles. For that purpose, fluorescent model silica nanoparticles were interconnected with the biocompatible polysaccharide agarose, building up cylindrical particl...

  18. Pulsation Calculation of Cylindrical Underwater Gas Explosion Products in Well

    Directory of Open Access Journals (Sweden)

    A. M. Sheiko

    2014-06-01

    Full Text Available The paper considers a mathematical model of pulsation process of cylindrical underwater gas explosion products in the well at gas-impulse regeneration filters. A differential equation of the second-order with constant coefficients has been derived. A special calculation program has been developed to solve the equation. Expressions for calculation of maximum radius of cylindrical explosion chamber at the end of expansion process and pressure impulse in the first half-period pulsation.

  19. On cylindrically converging shock waves shaped by obstacles

    Energy Technology Data Exchange (ETDEWEB)

    Eliasson, V; Henshaw, W D; Appelo, D

    2007-07-16

    Motivated by recent experiments, numerical simulations were performed of cylindrically converging shock waves. The converging shocks impinged upon a set of zero to sixteen regularly space obstacles. For more than two obstacles the resulting diffracted shock fronts formed polygonal shaped patterns near the point of focus. The maximum pressure and temperature as a function of number of obstacles were studied. The self-similar behavior of cylindrical, triangular and square-shaped shocks were also investigated.

  20. Experiments of cylindrical isentropic compression by ultrahigh magnetic field

    OpenAIRE

    Gu Zhuowei; Zhou Zhongyu; Zhang Chunbo; Tang Xiaosong; Tong Yanjin; Zhao Jianheng; Sun Chengwei

    2015-01-01

    The high Explosive Magnetic Flux Implosion Compression Generator (EMFICG) is a kind of unique high energy density dynamic technique with characters like ultrahigh pressure and low temperature rising and could be suitable as a tool of cylindrical isentropic compression. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP) have developed EMFICG technique and realized cylindrical isentropic compression. In the experiments, a seed magnetic field of 5–6 Tesla were bui...

  1. Elliptic Cylindrical Invisibility Cloak, a Semianalytical Approach Using Mathieu Functions

    OpenAIRE

    Cojocaru, E.

    2008-01-01

    An elliptic cylindrical wave expansion method by using Mathieu functions is developed to obtain the scattering field for a two-dimensional elliptic cylindrical invisibility cloak. The cloak material parameters are obtained from the spatial transformation approach. A near-ideal model of the invisibility cloak is set up to solve the boundary problem at the inner boundary in the cloak shell. The proposed design provides a more practical cloak geometry when compared to previous designs of ellipti...

  2. The gravitation energy for a cylindrically and spherically symmetrical system

    CERN Document Server

    Sosnovskiy, R

    2005-01-01

    It has been shown that t00 component of the energy-momentum pseudotensor in the case of cylindrically symmetrical static gravitational field cannot be interpreted as energy density of the gravitation field. An approach has been suggested allows one to express the energy density of the cylindrically or spherically symmetrical static gravitation field in terms of the metric tensor components. The approach based on the consideration of the process of isothermal compression of a cylinder consisted of incoherent matter.

  3. The gravitation energy for a cylindrically and spherically symmetrical system

    OpenAIRE

    Sosnovskiy, Roald

    2005-01-01

    It has been shown that t00 component of the energy-momentum pseudotensor in the case of cylindrically symmetrical static gravitational field cannot be interpreted as energy density of the gravitation field. An approach has been suggested allows one to express the energy density of the cylindrically or spherically symmetrical static gravitation field in terms of the metric tensor components. The approach based on the consideration of the process of isothermal compression of a cylinder consiste...

  4. The covariant electromagnetic Casimir effect for real conducting cylindrical shells

    International Nuclear Information System (INIS)

    Using covariant quantization of the electromagnetic field, the Casimir force per unit area experienced by a long conducting cylindrical shell, under both Dirichlet and Neumann boundary conditions, is calculated. The renormalization procedure is based on the plasma cut-off frequency for real conductors. The real case of a gold (silver) cylindrical shell is considered and the corresponding electromagnetic Casimir pressure is computed. It is discussed that the Dirichlet and Neumann problems should be considered separately without adding their corresponding results.

  5. An Approximate Solution for Spherical and Cylindrical Piston Problem

    Indian Academy of Sciences (India)

    S K Singh; V P Singh

    2000-02-01

    A new theory of shock dynamics (NTSD) has been derived in the form of a finite number of compatibility conditions along shock rays. It has been used to study the growth and decay of shock strengths for spherical and cylindrical pistons starting from a non-zero velocity. Further a weak shock theory has been derived using a simple perturbation method which admits an exact solution and also agrees with the classical decay laws for weak spherical and cylindrical shocks.

  6. Environmental and geometric optimisation of cylindrical drinking water storage tanks

    OpenAIRE

    Sanjuan Delmás, David; Gabarrell Durany, Xavier; Rieradevall, Joan; Hernando-Canovas, Elena; Pujadas, Pablo; De la Fuente, Albert; Josa Garcia-Tornel, Alejandro

    2015-01-01

    The final publication is available at Springer via http://dx.doi.org/10.1007/s11367-015-0963-y Purpose: Urban water cycle construction processes are an important element to consider when assessing the sustainability of urban areas. The present study focuses on a structural and environmental analysis of cylindrical water tanks. The goal is to optimise cylindrical water tanks from both an environmental (environmental impacts due of life cycle assessment (LCA)) and a geometric perspective (bu...

  7. The deformation of cylindrical shells subjected to radial loads

    OpenAIRE

    Madureira, M.L.R.; Fonseca, E.M.M.; Melo, F.J.M.Q. de

    2010-01-01

    Cylindrical shells have a simple geometry and application in pressure vessels and piping engineering. The development of calculation algorithms in structural project is impelled by a constant challenge in the search of more accurate and fast design tools in engineering. The objective of this work is to contribute with a simple and reliable numerical tool for the stress analysis of cylindrical vessels subjected to generalized forces. A hybrid formulation in the definition of forces...

  8. Optical analysis on induction of focal accommodation using cylindrical lenses

    Science.gov (United States)

    Mano, Yuichiro; Kakeya, Hideki

    2008-02-01

    In the present paper the authors analyze detailed optics of stereoscopic display combining cylindrical lenses and embedded striped patterns, which has been proposed to reduce the contradiction between binocular parallax and focal accommodation of the eyes. The proposed system lets the viewer see an image including high frequency striped patterns through a cylindrical lens. When the viewer is shown a striped pattern through a cylindrical lens, the depth on which his/her eyes focus depends on the inclination angle of stripes, for the cylindrical lens works as a lens with different focal length depending on the orientation of lines. To control the status of accommodation correctly, it is necessary to obtain the correspondence between the inclination angle of stripes and the focusing distance. To attain this goal we make a computer simulator to calculate the 3D optical paths. The validity of the computer simulator is confirmed by physical experiments with a cylindrical lens and a camera finder to measure the focal convergence of striped lines. We also confirm that this system can induce desired focal accommodation by measuring the eyes of the viewer seeing striped patterns through a cylindrical lens.

  9. Micropatterning on cylindrical surfaces via electrochemical etching using laser masking

    International Nuclear Information System (INIS)

    Highlights: • Various micropatterns were fabricated on the cylindrical surface of a stainless steel shaft. • Selective electrochemical dissolution was achieved via a series process of laser masking and electrochemical etching. • Laser masking characteristics on the non-planar surface were investigated. • A uniform mask layer was formed on the cylindrical surface via synchronized laser line scanning with a rotary system. • The characteristics of electrochemical etching on the non-planar surface were investigated. - Abstract: This paper proposes a method of selective electrochemical dissolution on the cylindrical surfaces of stainless steel shafts. Selective electrochemical dissolution was achieved via electrochemical etching using laser masking. A micropatterned recast layer was formed on the surface via ytterbium-doped pulsed fiber laser irradiation. The micropatterned recast layer could be used as a mask layer during the electrochemical etching process. Laser masking condition to form adequate mask layer on the planar surface for etching cannot be used directly on the non-planar surface. Laser masking condition changes depending on the morphological surface. The laser masking characteristics were investigated in order to form a uniform mask layer on the cylindrical surface. To minimize factors causing non-uniformity in the mask layer on the cylindrical surface, synchronized laser line scanning with a rotary system was applied during the laser masking process. Electrochemical etching characteristics were also investigated to achieve deeper etched depth, without collapsing the recast layer. Consequently, through a series process of laser masking and electrochemical etching, various micropatternings were successfully performed on the cylindrical surfaces

  10. Reactor building

    International Nuclear Information System (INIS)

    The whole reactor building is accommodated in a shaft and is sealed level with the earth's surface by a building ceiling, which provides protection against penetration due to external effects. The building ceiling is supported on walls of the reactor building, which line the shaft and transfer the vertical components of forces to the foundations. The thickness of the walls is designed to withstand horizontal pressure waves in the floor. The building ceiling has an opening above the reactor, which must be closed by cover plates. Operating equipment for the reactor can be situated above the building ceiling. (orig./HP)

  11. Heterogeneous reactors

    International Nuclear Information System (INIS)

    The microscopic study of a cell is meant for the determination of the infinite multiplication factor of the cell, which is given by the four factor formula: K(infinite) = n(epsilon)pf. The analysis of an homogeneous reactor is similar to that of an heterogeneous reactor, but each factor of the four factor formula can not be calculated by the formulas developed in the case of an homogeneous reactor. A great number of methods was developed for the calculation of heterogeneous reactors and some of them are discussed. (Author)

  12. Comparison of multigroup and few-group calculations of fast power reactor parameters

    International Nuclear Information System (INIS)

    The basic parameters of a fast breeder reactor in two-dimensional cylindrical geometry and in multi- and few-group diffusion approximation were calculated and compared. Two different types of reactor were considered, viz., homogeneous and heterogeneous. The results can serve as a quantitative aid for the choice of the proper number of groups for the calculations of various reactor parameters with required accuracy. (author)

  13. Sub-pixel estimation of tree cover and bare surface densities using regression tree analysis

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Zangrando Toneli

    2011-09-01

    Full Text Available Sub-pixel analysis is capable of generating continuous fields, which represent the spatial variability of certain thematic classes. The aim of this work was to develop numerical models to represent the variability of tree cover and bare surfaces within the study area. This research was conducted in the riparian buffer within a watershed of the São Francisco River in the North of Minas Gerais, Brazil. IKONOS and Landsat TM imagery were used with the GUIDE algorithm to construct the models. The results were two index images derived with regression trees for the entire study area, one representing tree cover and the other representing bare surface. The use of non-parametric and non-linear regression tree models presented satisfactory results to characterize wetland, deciduous and savanna patterns of forest formation.

  14. An OPAL measurement of the τ- → e-/-bareντ Branching Ratio

    International Nuclear Information System (INIS)

    The branching ratio for the decay τ- → e-/-bareντ has been measured using data collected by the OPAL experiment at LEP. In total 33073 τ- → e-/-bareντ candidates were identified from a sample of 186197 selected τ decays, giving a branching ratio of Be (17.81 ± 0.09 (stat) ± 0.06 (syst))%. This result is combined with other electroweak measurements to test e - μ and μ - τ universality in charged-current weak interactions at the level of 0.5%. Additionally, a value of the strong coupling constant αs (m2τ) has been extracted from Be and evolved to the Zo mass scale to give αs (m2Z) = 0.1204 ± 0.0011 (exp)+0.0021-0.0019 (theory)

  15. A multi-frequency radiometric measurement of soil moisture content over bare and vegetated fields

    Science.gov (United States)

    Wang, J. R.; Schmugge, T. J.; Gould, W. I.; Glazar, W. S.; Fuchs, J. E.; Mcmurtrey, J. E., III

    1982-01-01

    An experiment on soil moisture remote sensing was conducted during July to September 1981 on bare, grass, and alfalfa fields at frequencies of 0.6, 1.4, 5.0, and 10.6 GHz with radiometers mounted on mobile towers. The results confirm the frequency dependence of sensitivity reduction due to the presence of vegetation cover. For the type of vegetated fields reported here, the vegetation effect is appreciable even at 0.6 GHz. Measurements over bare soil show that when the soil is wet, the measured brightness temperature is lowest at 5.0 GHz and highest at 0.6 GHz, a result contrary to the expectation based on the estimated dielectric permittivity of soil-water mixtures and the current radiative transfer model in that frequency range.

  16. Quantifying and isolating stable soil organic carbon using long-term bare fallow experiment

    DEFF Research Database (Denmark)

    Barré, P; Eglin, T; Christensen, Bent Tolstrup;

    2010-01-01

    The stability of soil organic matter (SOM) is a major source of uncertainty in predicting atmospheric CO2 concentration during the 21st century. Isolating the stable soil carbon (C) from other, more labile, C fractions in soil is of prime importance for calibrating soil C simulation models......, and gaining insights into the mechanisms that lead to soil C stability. Long-term experiments with continuous bare fallow (vegetation-free) treatments in which the decay of soil C is monitored for decades after all inputs of C have stopped, provide a unique opportunity to assess the quantity of stable soil C....... We analyzed data from six bare fallow experiments of long-duration (>30 yrs), covering a range of soil types and climate conditions, and sited at Askov (Denmark), Grignon and Versailles (France), Kursk (Russia), Rothamsted (UK), and Ultuna (Sweden). A conceptual three pool model dividing soil C...

  17. Asymmetric Bulkheads for Cylindrical Pressure Vessels

    Science.gov (United States)

    Ford, Donald B.

    2007-01-01

    Asymmetric bulkheads are proposed for the ends of vertically oriented cylindrical pressure vessels. These bulkheads, which would feature both convex and concave contours, would offer advantages over purely convex, purely concave, and flat bulkheads (see figure). Intended originally to be applied to large tanks that hold propellant liquids for launching spacecraft, the asymmetric-bulkhead concept may also be attractive for terrestrial pressure vessels for which there are requirements to maximize volumetric and mass efficiencies. A description of the relative advantages and disadvantages of prior symmetric bulkhead configurations is prerequisite to understanding the advantages of the proposed asymmetric configuration: In order to obtain adequate strength, flat bulkheads must be made thicker, relative to concave and convex bulkheads; the difference in thickness is such that, other things being equal, pressure vessels with flat bulkheads must be made heavier than ones with concave or convex bulkheads. Convex bulkhead designs increase overall tank lengths, thereby necessitating additional supporting structure for keeping tanks vertical. Concave bulkhead configurations increase tank lengths and detract from volumetric efficiency, even though they do not necessitate additional supporting structure. The shape of a bulkhead affects the proportion of residual fluid in a tank that is, the portion of fluid that unavoidably remains in the tank during outflow and hence cannot be used. In this regard, a flat bulkhead is disadvantageous in two respects: (1) It lacks a single low point for optimum placement of an outlet and (2) a vortex that forms at the outlet during outflow prevents a relatively large amount of fluid from leaving the tank. A concave bulkhead also lacks a single low point for optimum placement of an outlet. Like purely concave and purely convex bulkhead configurations, the proposed asymmetric bulkhead configurations would be more mass-efficient than is the flat

  18. Bonding bare die LEDs on PET foils for lighting applications: thermal design modeling and bonding experiments

    OpenAIRE

    van den Ende, Daan; Kusters, Roel; Cauwe, Maarten; A de Waal; van den Brand, Jeroen

    2012-01-01

    Integration of LEDs on flexible foil substrates is of interest for flexible lighting applications and flexible photonic devices. A matrix of LEDs on a foil combined with a diffuser can be a potential alternative for flexible OLED lighting devices. Preferably, these LEDs are integrated in an unpackaged, bare die form as it reduces cost, footprint and thickness. As a substrate, preferably low cost materials like polyesters (PET) are being used, especially for large area devices. However, the us...

  19. Low work-function coating for an entirely propellantless bare electrodynamic tether

    OpenAIRE

    Williams, John D.; Sanmartin, Juan R.; Rand, Lauren P.

    2012-01-01

    We present the possibility of a low work-function material, calcium aluminate electride, being used for a coating on a bare electrodynamic tether system. Analyses suggest that the coating would eliminate the need for an active cathodic device like a hollow cathode and, consequently, eliminate the need for an expellant to the hollow cathode, thus resulting in an electrodynamic tether system that requires no consumables. Applications include on-orbit power generation and deorbiting debris fr...

  20. Optical coupling of bare optoelectronic components and flexographically printed polymer waveguides in planar optronic systems

    Science.gov (United States)

    Wang, Yixiao; Wolfer, Tim; Lange, Alex; Overmeyer, Ludger

    2016-05-01

    Large scale, planar optronic systems allowing spatially distributed functionalities can be well used in diverse sensor networks, such as for monitoring the environment by measuring various physical quantities in medicine or aeronautics. In these systems, mechanically flexible and optically transparent polymeric foils, e.g. polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET), are employed as carrier materials. A benefit of using these materials is their low cost. The optical interconnections from light sources to light transmission structures in planar optronic systems occupy a pivotal position for the sensing functions. As light sources, we employ the optoelectronic components, such as edgeemitting laser diodes, in form of bare chips, since their extremely small structures facilitate a high integration compactness and ensure sufficient system flexibility. Flexographically printed polymer optical waveguides are deployed as light guiding structures for short-distance communication in planar optronic systems. Printing processes are utilized for this generation of waveguides to achieve a cost-efficient large scale and high-throughput production. In order to attain a high-functional optronic system for sensing applications, one of the most essential prerequisites is the high coupling efficiency between the light sources and the waveguides. Therefore, in this work, we focus on the multimode polymer waveguide with a parabolic cross-section and investigate its optical coupling with the bare laser diode. We establish the geometrical model of the alignment based on the previous works on the optodic bonding of bare laser diodes and the fabrication process of polymer waveguides with consideration of various parameters, such as the beam profile of the laser diode, the employed polymer properties of the waveguides as well as the carrier substrates etc. Accordingly, the optical coupling of the bare laser diodes and the polymer waveguides was simulated

  1. Quantifying and isolating stable soil organic carbon using long-term bare fallow experiments

    Directory of Open Access Journals (Sweden)

    P. Barré

    2010-11-01

    Full Text Available The stability of soil organic matter (SOM is a major source of uncertainty in predicting atmospheric CO2 concentration during the 21st century. Isolating the stable soil carbon (C from other, more labile, C fractions in soil is of prime importance for calibrating soil C simulation models, and gaining insights into the mechanisms that lead to soil C stability. Long-term experiments with continuous bare fallow (vegetation-free treatments in which the decay of soil C is monitored for decades after all inputs of C have stopped, provide a unique opportunity to assess the quantity of stable soil C. We analyzed data from six bare fallow experiments of long-duration (>30 yrs, covering a range of soil types and climate conditions, and sited at Askov (Denmark, Grignon and Versailles (France, Kursk (Russia, Rothamsted (UK, and Ultuna (Sweden. A conceptual three pool model dividing soil C into a labile pool (turnover time of a several years, an intermediate pool (turnover time of a several decades and a stable pool (turnover time of a several centuries or more fits well with the long term C decline observed in the bare fallow soils. The estimate of stable C ranged from 2.7 g C kg−1 at Rothamsted to 6.8 g C kg−1 at Grignon. The uncertainty associated with estimates of the stable pool was large due to the short duration of the fallow treatments relative to the turnover time of stable soil C. At Versailles, where there is least uncertainty associated with the determination of a stable pool, the soil contains predominantly stable C after 80 years of continuous bare fallow. Such a site represents a unique research platform for characterization of the nature of stable SOM and its vulnerability to global change.

  2. Bare-State Time-Evolving Operator Solution to Raman Model in A Configuration

    Institute of Scientific and Technical Information of China (English)

    WUYing; NIEYi-Zhen; YANGXiao-Xue

    2003-01-01

    We derive exact analytical expressions of time-evolving bare-state operators of level occupation numbers and the photon numbers for a composite system consisting of a three-level atom interacting with two modes ofa quantized electromagnetic field in A configuration. These results demonstrate the oscillations with three-family frequencies for a nonzero detuning, which dramatically differ from the previous results showing only single-family Rabi oscillations.

  3. Replacing bare fallow with cover crops in an irrigated cropping system: soil salinity and salt leaching

    OpenAIRE

    Almendros García, Patricia; Gabriel Pérez, José Luis; Quemada Saenz-Badillos, Miguel

    2011-01-01

    In irrigated areas where cover crop establishment can be assured, consequent soil or nutrient conservation could increase sustainability of cropping systems. Replacing bare fallow with cover crops may increase sustainability by enhancing soil aggregate stability, water retention capacity or controlling nitrate leaching. Nevertheless, adoption of cover crops increase evapotranspiration and reduce water percolation beyond the root systems; therefore, it could lead to salt accumulation in the up...

  4. Occupation of bare habitats, an evolutionary precursor to soil specialization in plants.

    Science.gov (United States)

    Cacho, N Ivalú; Strauss, Sharon Y

    2014-10-21

    Plant soil specialists contribute greatly to global diversity; however, the ecoevolutionary forces responsible for generating this diversity are poorly understood. We integrate molecular phylogenies with descriptive and experimental ecological data, creating a powerful framework with which to elucidate forces driving soil specialization. Hypotheses explaining edaphic specialization have historically focused on costs of adaptation to elements (e.g., nickel, calcium/magnesium) and accompanying tradeoffs in competitive ability in benign soils. We combine in situ microhabitat data for 37 streptanthoid species (Brassicaceae), soil analyses, and competition experiments with their phylogeny to reconstruct selective forces generating serpentine soil endemism, which has four to five independent origins in this group. Coupling ancestral state reconstruction with phylogenetic independent contrasts, we examine the magnitude and timing of changes in soil and habitat attributes relative to inferred shifts to serpentine. We find large changes in soil chemistry at nodes associated with soil shifts, suggesting that elemental changes occurred concomitantly with soil transitions. In contrast, the amount of bare ground surrounding plants in the field ("bareness"), which is greater in serpentine environments, is conserved across soil-type shifts. Thus, occupation of bare environments preceded shifts to serpentine, and may serve as an evolutionary precursor to harsh elemental soils and environments. In greenhouse experiments, taxa from barer environments are poorer competitors, a tradeoff that may contribute to soil endemism. The hypothesis of occupation of bare habitats as a precursor of soil specialization can be tested in other systems with a similar integrative ecophylogenetic approach, thereby providing deeper insights into this rich source of biodiversity. PMID:25267640

  5. Introducing the notion of bare and effective mass via Newton's second law of motion

    OpenAIRE

    Pinto, Marcus Benghi

    2005-01-01

    The concepts of bare and effective mass are widely used within modern physics. Their meaning is discussed in advanced undergraduate and graduate courses such as solid state physics, nuclear physics and quantum field theory. Here, I discuss how these concepts may be introduced, at a very early stage, together with the discussion of Newton's second law of motion for a sliding block. The setting up of a simple equation for the effective mass will allow instructors to discuss how external paramet...

  6. Theoretical behaviour of calibration factors of bare mode SSNTD dosimeters for radon and thoron daughter products

    International Nuclear Information System (INIS)

    A closed mode Rn/Tn dosimeter consists of a cup having its open end covered with a filter paper to allow Rn/Tn gas, but not its progeny, to permeate through it. A SSNTD film is mounted inside the cup to register alpha tracks. The cup measures Rn/Tn gas concentration. In order to obtain information on the exposure of the daughter products, a detector is directly exposed to Rn/Tn atmosphere in uncovered or BARE mode. The theoretical work on the CLOSED mode dosimeter has already been reported. The present methodology deals with BARE mode dosimeters. The computation of calibration factors has been carried out for LR-115 and CR-39 detectors in case of both radon and thoron daughter products, and the results are inter compared. Experimental data are discussed in the light of the present study. The calibration factors for BARE mode detectors significantly depend on equilibrium factors (or the ventilation status of the sampled zone). The theoretical considerations are more appropriate to LR-115. In this case, the expected mode and range of field of field values, respectively, are: 8.0, 5-14 for Rn and 87.5, 18-230 tr.cm.-2/kBq.h.m.-3 for Tn. The values for CR-39 can be much larger in practice than theoretically expected. The experimental calibration factors, for the sake of their meaningful use, need to be reported along with the relevant equilibrium factors. The theoretical values or the theoretically extrapolated experimental values are applicable to the fields with known equilibrium factors. A twin-detector dosimeter comprising a CLOSED and a BARE mode detector is proposed for fields with unknown equilibrium factors. (author). 4 refs., 4 figs

  7. Characterization of diamond film and bare metal photocathodes as a function of temperature and surface preparation

    International Nuclear Information System (INIS)

    High current photocathodes using bare metal and polycrystalline diamond films illuminated by ultraviolet lasers are being developed at Los Alamos for use in a new generation of linear induction accelerators. These photocathodes must be able to produce multiple 60 ns pulses separated by several to tens of nanoseconds. The vacuum environment in which the photocathodes must operate is 10-5 torr. (author). 9 figs., 10 refs

  8. Paleomagnetism of the Miocene dikes in Bare Mountain, southwest Nevada: Implications for regional tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Gillett, S.L.; Karlin, R.E.; Schweickert, R.A. (Univ. of Nevada, Reno, NV (United States). Dept. of Geological Sciences)

    1993-04-01

    Paleomagnetic studies of N-striking Miocene quartz latite dikes (13.9 Ma), within Proterozoic and Paleozoic sedimentary rocks of Bare Mountain, have been conducted in an effort to determine the sense of post-middle Miocene tectonic tilting and rotation in the Bare Mountain region. A total of 56 oriented samples of dikes and wallrocks were collected from Tarantula Canyon (TC) and south of Joshua Hollow (JH), where the dikes intruded N-dipping Mississippian-Devonian limestone beds. Progressive thermal demagnetization and principal component analyses reveal a stable high temperature component of remanent magnetization that is carried by magnetite or hematite in different samples. Petrographic investigations, combined with thermal demagnetization analysis, indicate that magnetite is a primary phase and that hematite is secondary. Hematitic alteration in both wallrocks and dikes is probably hydrothermal following intrusion as the mean direction of both minerals overlap. The in situ mean magnetization directions from all dikes exhibit negative inclinations that correspond to a Tertiary reversed field. The data indicate that magnetization acquisition in the wallrocks and dikes postdates tilting of the beds and the no major remagnetization event has occurred since the intrusion. The results from TC imply that there has been no significant rotation of the northeast part of Bare Mountain since [minus]14 Ma. The authors further suggest that the E-W structural trends of Proterozoic and Paleozoic rocks at Bare Mountain are older than the middle Miocene dikes. Paleomagnetic data from dikes of JH show steeper inclinations and westerly declinations compared to the dike of TC. There are two interpretations to explain the differences: The dikes may have formed at different times in the same magmatic event and the directional differences are due to secular variation. Alternatively, the dikes at JH were tilted slightly to the north around a sub-horizontal axis.

  9. Heat and water transfer in bare topsoil and the lower atmosphere

    OpenAIRE

    ten Berge, H.F.M.

    1996-01-01

    This book describes an analysis of processes and factors that affect the energy balance of bare soil, and the associated exchange of heat and moisture at the surface. After a brief treatment of basic transport theory, the processes of soil-atmosphere interaction are expressed in a simulation algorithm. This algorithm provides an instrument to study the 'conditioning' effect of soil on the lower atmosphere, and vice versa. Examples of sensitivity analysis are presented, with emphasis on the be...

  10. Experimental electro-mechanical static characterization of IGBT bare die under controlled temperature

    OpenAIRE

    Belmehdi, Yassine; Azzopardi, Stephane; Delétage, Jean-Yves; Woirgard, Eric

    2010-01-01

    International audience Silicon dice soldered in power assemblies have to withstand simultaneously electrical, thermal and mechanical stress. Mechanical stress is an important issue because it will directly impact on both the device behaviour and power modules reliability. This paper focuses on the electro-mechanical static characterization of a planar gate IGBT by the help of experiments at controlled temperatures. A specific test bench is proposed to make the experiments on silicone bare ...

  11. Thermomechanical fatigue behavior of coated and bare nickel-based superalloy single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chataigner, E.; Remy, L.

    1996-12-31

    The thermal-mechanical fatigue behavior of chromium-aluminum coated [001] single crystals of AM1, a nickel-base superalloy for turbine blades, is studied using a diamond shape cycle from 600 to 1,100 C. Comparison with bare specimens does not show any significant difference in thermal-mechanical fatigue nor in isothermal low cycle fatigue at high temperature. Metallographic observations on fracture surfaces and longitudinal sections of specimens tested to fatigue life or to a definite fraction of expected life have shown that the major crack tends to initiate from casting micropores in the sub-surface area very early in bare and coated specimens, under low cycle fatigue or thermal-mechanical fatigue. But the interaction between oxidation and fatigue cracking seems to play a major role. A simple model proposed by Reuchet and Remy has been identified for this single crystal superalloy. Its application to the life prediction under low cycle fatigue and thermal-mechanical fatigue for bare and coated single crystals with different orientations is shown.

  12. Percutaneous Creation of Bare Intervascular Tunnels for Salvage of Thrombosed Hemodialysis Fistulas Without Recanalizable Outflow

    International Nuclear Information System (INIS)

    PurposeThis study aimed to retrospectively assess the efficacy of a bare intervascular tunnel for salvage of a thrombosed hemodialysis fistula. We examined the clinical outcomes and provided follow-up images of the bare intervascular tunnel.Materials and MethodsEight thrombosed fistulas lacked available recanalizable outflow veins were included in this study. These fistulas were salvaged by re-directing access site flow to a new outflow vein through a percutaneously created intervascular tunnel without stent graft placement. The post-intervention primary and secondary access patency rates were calculated using the Kaplan–Meier method.ResultsThe procedural and clinical success rates were 100 %. Post-intervention primary and secondary access patency at 300 days were 18.7 ± 15.8 and 87.5 ± 11.7 %, respectively. The mean follow-up period was 218.7 days (range 10–368 days). One patient died of acute myocardial infarction 10 days after the procedure. No other major complications were observed. Minor complications, such as swelling, ecchymosis, and pain around the tunnel, occurred in all of the patients.ConclusionsPercutaneous creation of a bare intervascular tunnel is a treatment option for thrombosed hemodialysis fistulas without recanalizable outflow in selected patients

  13. Percutaneous Creation of Bare Intervascular Tunnels for Salvage of Thrombosed Hemodialysis Fistulas Without Recanalizable Outflow

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Matt Chiung-Yu, E-mail: jjychen@gmail.com [Yuan’s General Hospital, Department of Interventional Radiology (China); Wang, Yen-Chi [E-Da Hospital, Department of Radiology (China); Weng, Mei-Jui [Kaohsiung Veterans General Hospital, Department of Radiology (China)

    2015-08-15

    PurposeThis study aimed to retrospectively assess the efficacy of a bare intervascular tunnel for salvage of a thrombosed hemodialysis fistula. We examined the clinical outcomes and provided follow-up images of the bare intervascular tunnel.Materials and MethodsEight thrombosed fistulas lacked available recanalizable outflow veins were included in this study. These fistulas were salvaged by re-directing access site flow to a new outflow vein through a percutaneously created intervascular tunnel without stent graft placement. The post-intervention primary and secondary access patency rates were calculated using the Kaplan–Meier method.ResultsThe procedural and clinical success rates were 100 %. Post-intervention primary and secondary access patency at 300 days were 18.7 ± 15.8 and 87.5 ± 11.7 %, respectively. The mean follow-up period was 218.7 days (range 10–368 days). One patient died of acute myocardial infarction 10 days after the procedure. No other major complications were observed. Minor complications, such as swelling, ecchymosis, and pain around the tunnel, occurred in all of the patients.ConclusionsPercutaneous creation of a bare intervascular tunnel is a treatment option for thrombosed hemodialysis fistulas without recanalizable outflow in selected patients.

  14. Thermally treated bare gold nanoparticles for colorimetric sensing of copper ions

    International Nuclear Information System (INIS)

    We demonstrate a sensitive and rapid colorimetric assay for selective detection of copper ions based on the strong coordination between Cu(II) ions and the tetrahydroxyaurate anions [Au(OH)4]− on the surface of thermally treated bare gold nanoparticles (GNPs). The method for making the unmodified GNPs is simple and results in a nanomaterial with a highly specific response to Cu(II). The thermal treatment of the bare GNPs and the recognition of Cu(II) ions is accomplished in a single step within 5 min. The presence of Cu(II) causes the color to change from red to purple-blue. The limit of detection (LOD) is 0.04 μM of Cu(II) when using UV–vis spectrometry and rotating the absorbances at 650 and 515 nm, respectively. The method also is amenable to bare eye (visual) inspection and in this case has an LOD of 2.0 μM of Cu(II). (author)

  15. An evaluation of the simulated bare soil evaporation of an atmospheric model

    Science.gov (United States)

    Schulz, Jan-Peter; Vogel, Gerd

    2016-04-01

    Land surface processes have a significant impact on near-surface atmospheric phenomena. They determine, among others, near-surface sensible and latent heat fluxes and the radiation budget, and thus influence atmosphere and land characteristics, such as temperature and humidity, the structure of the planetary boundary layer, and even cloud formation processes. It is therefore important to simulate the land surface processes in atmospheric models as realistically as possible. Verifications have shown that the bare soil evaporation computed by the land surface scheme TERRA of the COSMO atmospheric model is systematically overestimated. Since this flux is part of the surface water and energy balance it affects, for instance, the other components of the turbulent heat fluxes as well as the soil water content and the surface temperature. Data from the Meteorological Observatory Lindenberg of the German Meteorological Service were used to analyse this model behaviour. In the standard model configuration of TERRA, the formulation of bare soil evaporation is based on the Biosphere Atmosphere Transfer Scheme (BATS), following the work by R. E. Dickinson. In order to reduce the excessive evaporation simulated by BATS, other formulations for the bare soil evaporation were tested in TERRA. In turned out that a scheme based on a resistance formulation efficiently reduces the simulated vapour flux, leading to a better agreement with the measurements.

  16. Comparison and analysis of bare soil evaporation models combined with ASTER data in Heihe River Basin

    Directory of Open Access Journals (Sweden)

    Yan-xia KANG

    2009-12-01

    Full Text Available Based on ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer remote sensing data, bare soil evaporation was estimated with the Penman-Monteith model, the Priestley-Taylor model, and the aerodynamics model. Evaporation estimated by each of the three models was compared with actual evaporation, and error sources of the three models were analyzed. The mean absolute relative error was 9% for the Penman-Monteith model, 14% for the Priestley-Taylor model, and 32% for the aerodynamics model; the Penman-Monteith model was the best of these three models for estimating bare soil evaporation. The error source of the Penman-Monteith model is the neglect of the advection estimation. The error source of the Priestley-Taylor model is the simplification of the component of aerodynamics as 0.72 times the net radiation. The error source of the aerodynamics model is the difference of vapor pressure and neglect of the radiometric component. The spatial distribution of bare soil evaporation is evident, and its main factors are soil water content and elevation.

  17. Assembly and integration of thin bare die using laser direct-write

    Science.gov (United States)

    Piqué, Alberto; Charipar, Nicholas A.; Auyeung, Ray C. Y.; Kim, Heungsoo; Mathews, Scott A.

    2007-02-01

    Laser-based direct-write (LDW) processes offer unique advantages for the transfer of unpackaged semiconductor bare die for microelectronics assembly applications. Using LDW it is possible to release individual devices from a carrier substrate and transfer them inside a pocket or recess in a receiving substrate using a single UV laser pulse, thus per-forming the same function as pick-and-place machines currently employed in microelectronics assembly. However, conventional pick-and-place systems have difficulty handling small (Naval Research Laboratory, we have demonstrated the laser release and transfer of intact 1 mm2 wafers with thicknesses down to 10 microns and with high placement accuracy using LDW techniques. Furthermore, given the gentle nature of the laser forward transfer process it is possible to transfer semiconductor bare die of sizes ranging from 0.5 to 10 mm2 without causing any damage to their circuits. Once the devices have been transferred, the same LDW system can then be used to print the metal patterns required to interconnect each device. The implementation of this technique is ideally suited for the assembly of microelectronic components and systems while allowing the overall circuit design and layout to be easily modified or adapted to any specific application or form factor including 3-D architectures. This paper describes how the LDW process can be used as an effective laser die transfer tool and will present analysis of the laser-driven release process as applied to various types of silicon bare dies.

  18. Patches of bare ground as a staple commodity for declining ground-foraging insectivorous farmland birds.

    Directory of Open Access Journals (Sweden)

    Michael Schaub

    Full Text Available Conceived to combat widescale biodiversity erosion in farmland, agri-environment schemes have largely failed to deliver their promises despite massive financial support. While several common species have shown to react positively to existing measures, rare species have continued to decline in most European countries. Of particular concern is the status of insectivorous farmland birds that forage on the ground. We modelled the foraging habitat preferences of four declining insectivorous bird species (hoopoe, wryneck, woodlark, common redstart inhabiting fruit tree plantations, orchards and vineyards. All species preferred foraging in habitat mosaics consisting of patches of grass and bare ground, with an optimal, species-specific bare ground coverage of 30-70% at the foraging patch scale. In the study areas, birds thrived in intensively cultivated farmland where such ground vegetation mosaics existed. Not promoted by conventional agri-environment schemes until now, patches of bare ground should be implemented throughout grassland in order to prevent further decline of insectivorous farmland birds.

  19. Models for calculating phreatic water evaporation on bare and Tamarix-vegetated lands

    Institute of Scientific and Technical Information of China (English)

    HU Shunjun; TIAN Changyan; SONG Yudong; CHEN Xiaobing; LI Yuetan

    2006-01-01

    Groundwater is the main source of water consumption of natural vegetation in arid regions.It is an effective approach to study ecological water demand of natural vegetation by phreatic evaporation.In order to study the ecological water demand of Tarim river basin, based on the observation data of phreatic evaporation on bare lands at the Aksu Water Balance Experimental station from 1989 to 1996, by analyzing the relationship of phreatic evaporation,depth of phreatic surface and evaporation of water,taking the limit rate of phreatic evaporation as the control condition, and based on the objective law that the relation between phreatic evaporation and evaporation of water is nonlinear, we establish models for calculating phreatic evaporation on bare land,which can fully reflect the law of phreatic evaporation in the Tarim river basin. According to the data of depth of phreatic surface and soil moisture when pheratic level decline is caused just by evapotranspiration on Tamarix-vegetated land from 2003 to 2004, we calculate the amount of phreatic evaporation and set up models for calculating phreatic evaporation on Tamarix- vegetated land. Phreatic evaporation on bare land and Tamarix-vegetated land could be transformed each other by a Tamarix vegetation conversion coefficient. The test results show that the calculation accuracy of the models is high and the models are suitable for Tarim river basin.

  20. Analysis of heel pad tissues mechanics at the heel strike in bare and shod conditions.

    Science.gov (United States)

    Fontanella, C G; Forestiero, A; Carniel, E L; Natali, A N

    2013-04-01

    A combined experimental and numerical approach is used to investigate the interaction phenomena occurring between foot and footwear during the heel strike phase of the gait. Two force platforms are utilised to evaluate the ground reaction forces of a subject in bare and shod walking. The reaction forces obtained from the experimental tests are assumed as loading conditions for the numerical analyses using three dimensional models of the heel region and of the running shoe. The heel pad region, as fat and skin tissues, is described by visco-hyperelastic and fibre-reinforced hyperelastic formulations respectively and bone region by a linear orthotropic formulation. Different elastomeric foams are considered with regard to the outsole, the midsole and the insole layers. The mechanical properties are described by a hyperfoam formulation. The evaluation of the mechanical behaviour of the heel pad tissues at the heel strike in bare and shod conditions is performed considering different combinations of materials for midsole and insole layers. Results allow for the definition of the influence of different material characteristics on the mechanical response of the heel pad region, in particular showing the compressive stress differentiation in the bare and shod conditions. PMID:22789809

  1. Relating variation of dust on snow to bare soil dynamics in the western United States

    International Nuclear Information System (INIS)

    The deposition of desert dust to mountain snow directly impacts the hydrologic cycle and water resource management through the depression of snow albedo and acceleration of snowmelt. However, the key processes that control the variation of dust deposition to snow are poorly understood. Here we relate the bare soil exposure from the moderate resolution imaging spectroradiometer (MODIS) reflectance data for the period of 2002–2011, with dust loading in snow at downwind mountain sites in southern Colorado, the United States. We found that, for many pixels, remotely sensed fraction of bare soil in the dust-emitting area is significantly correlated with end-of-season dust concentrations in snow, and that the highest number of significantly correlated pixels in the dust-source area corresponds well with the period of peak dust deposition in the mountain snow (April–May). This analysis indicates that surface conditions in the dust-source area may provide first-order controls on emission of dust and deposition of that dust to the mountain snowcover. A preliminary analysis of precipitation records indicates that bare ground cover is strongly affected by prior rainfall in the months preceding the dust-emission season. (letter)

  2. Studies on equilibrium analysis and cylindrical model of low aspect ratio tokamak

    International Nuclear Information System (INIS)

    The low-aspect-ratio tokamak is expected to realize a compact and economical fusion reactor. This paper presents a equilibrium study of low-aspect-ratio tokamaks for the basis of both of Magnetohydrodynamic (MHD) analysis and cylindrical approximation model. Since its external toroidal field coil does not have enough surrounding space for the installation of neutron shielding material, it should be made of a normal conductor, whose current density and the resistive power loss should be estimated. On the basis of the cylindrical approximation model, the relationships are derived between the resistive power loss and various plasma parameters as aspect ratio, elongation, safety factor at the edge, and total beta value. The resistive power loss can be decreased by decreasing aspect ratio, however, neutron wall loading and the total beta increase. It is found that they can be in the reasonable quantitative range by the appropriate selections of the plasma parameters. The evaluation is made of the applicability of the model by comparing the results with those of the numerical MHD analysis. (author)

  3. Electrical and optical characterization of a pulsed discharge in an inverted cylindrical magnetron

    Science.gov (United States)

    Vozniy, O. V.; Duday, D.; Luciu, I.; Wirtz, T.

    2014-08-01

    An inverted cylindrical magnetron operating in pulsed mode was developed, with a rotating unbalanced system of magnets. The magnetic field was calculated using the finite integration technique in order to determine the optimal anode-to-cathode distance inside the reactor. A cylindrical titanium target was used for our experiments. The average power input was varied between 500 and 1300 W leading to low power densities varying between 0.9 and 2.4 W cm-2. The frequency was fixed at a low value of 250 Hz, suitable for depositing Ti and TiO2 at low temperatures on polymer substrates. Long on-time pulses (400 µs) were used in order to reach interesting deposition rates (>1 µm h-1). A transition from metallic to oxide mode was observed for all power inputs. Time-resolved optical emission spectroscopy was used for the investigation of plasma dynamics during the on-time pulse in both metallic and reactive regimes. Three phases of discharge evolution were identified in the metallic mode: the Ar-dominated phase, followed by a transition zone and a Ti-dominated phase. The emission of Ti species completely disappeared in the reactive mode, associated with the fact that titanium atoms left the target surface as TiOx molecular fragments. In conclusion, the deposition system and conditions used resulted in a new mode of TiO2 deposition.

  4. Development of a code in three-dimensional cylindrical geometry based on analytic function expansion nodal (AFEN) method

    International Nuclear Information System (INIS)

    There is growing interest in developing pebble bed reactors (PBRs) as a candidate of very high temperature gas-cooled reactors (VHTRs). Until now, most existing methods of nuclear design analysis for this type of reactors are base on old finite-difference solvers or on statistical methods. But for realistic analysis of PBRs, there is strong desire of making available high fidelity nodal codes in three-dimensional (r,θ,z) cylindrical geometry. Recently, the Analytic Function Expansion Nodal (AFEN) method developed quite extensively in Cartesian (x,y,z) geometry and in hexagonal-z geometry was extended to two-group (r,z) cylindrical geometry, and gave very accurate results. In this thesis, we develop a method for the full three-dimensional cylindrical (r,θ,z) geometry and implement the method into a code named TOPS. The AFEN methodology in this geometry as in hexagonal geometry is 'robus' (e.g., no occurrence of singularity), due to the unique feature of the AFEN method that it does not use the transverse integration. The transverse integration in the usual nodal methods, however, leads to an impasse, that is, failure of the azimuthal term to be transverse-integrated over r-z surface. We use 13 nodal unknowns in an outer node and 7 nodal unknowns in an innermost node. The general solution of the node can be expressed in terms of that nodal unknowns, and can be updated using the nodal balance equation and the current continuity condition. For more realistic analysis of PBRs, we implemented em Marshak boundary condition to treat the incoming current zero boundary condition and the partial current translation (PCT) method to treat voids in the core. The TOPS code was verified in the various numerical tests derived from Dodds problem and PBMR-400 benchmark problem. The results of the TOPS code show high accuracy and fast computing time than the VENTURE code that is based on finite difference method (FDM)

  5. Plasma reactor

    OpenAIRE

    Molina Mansilla, Ricardo; Erra Serrabasa, Pilar; Bertrán Serra, Enric

    2008-01-01

    [EN] A plasma reactor that can operate in a wide pressure range, from vacuum and low pressures to atmospheric pressure and higher pressures. The plasma reactor is also able to regulate other important settings and can be used for processing a wide range of different samples, such as relatively large samples or samples with rough surfaces.

  6. Reactor physics

    International Nuclear Information System (INIS)

    Progress in research on reactor physics in 1997 at the Belgian Nuclear Research Centre SCK/CEN is described. Activities in the following four domains are discussed: core physics, ex-core neutron transport, experiments in Materials Testing Reactors, international benchmarks

  7. Sloshing suppression by bulkhead in cylindrical and co-axial cylindrical liquid vessels

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Nobuyuki [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan). Research Inst.; Mieda, Tsutomu; Jitsu, Kouji [Ishikawajima-Harima Heavy Industries Co. Ltd. Yokohama (Japan); Shibata, Heki [Yokohama National Univ. (Japan)

    1995-11-01

    This paper presents the effectiveness of bulkhead in suppressing the sloshing in cylindrical and co-axial double cylinder vessels containing liquid. The bulkhead is hung vertically from the vessel top so as to divide it into two equal sectors (in the annulus part for the latter type) but leaving enough space under its lower end for free (though somewhat perturbed) flow of the liquid. By deriving Lagrangian equations for the sloshing motion, it is shown that the sloshing mode is dissociated into two non-coupling modes of the U-tube mode and the bulkhead mode, both contributing to suppressing sloshing highly effectively. The practical utility of this simplified analysis has been verified by a series of shaking table experiments conducting with small model tanks and by the finite difference method of analysis by Flow-3D, a computational fluid dynamics code.

  8. Runoff and Sediment Delivery from Bare and Graveled Forest Road Approaches to Stream Crossings

    Science.gov (United States)

    Brown, K. R.; McGuire, K. J.; Aust, W. M.

    2012-12-01

    Forested watersheds are typically associated with high quality water yield, yet forest roads and trails can adversely impact water quality draining forested watersheds. Increased stream sedimentation from forest road stream crossings often represents the most significant water quality threat associated with forestry operations. Quantification of sediment delivery rates is essential for the prescription of Best Management Practices (BMPs) that adequately address forest road stormwater runoff. Two different field experiments were implemented in the Virginia Piedmont to achieve the objectives of quantifying sediment delivery from forest roads where the road meets the stream (the road approach) and evaluating the sediment reduction efficacy of partially graveling road approaches. A forest operational experiment that included sediment traps and differential leveling was used to measure sediment delivery from five bare and four fully graveled road approaches for one year (August 2011 through July 2012). Rainfall simulation experiments were performed on six additional approaches to measure stormwater runoff volume, infiltration, and sediment delivery for 10 to 50-minute rain events with rainfall recurrence intervals of sediment trap study provides annual sediment delivery rates for bare and fully graveled road approaches. The rainfall simulation experiments characterize sediment delivery during storm events and provide an evaluation of different levels of Best Management Practice (BMP) implementation (i.e. ¼ to full gravel coverage) to minimize sediment inputs from road approaches. Sediment delivery from both experiments was related to rainfall amount, timing, and intensity, as well as road approach characteristics such as length, slope, and percentage of bare soil through stepwise multiple regression analysis. We found that the most important explanatory variables of sediment delivery over time are rainfall amount and approach length. Sediment delivery rates from the

  9. Hydrodynamic Reaction Model of a Spouted Bed Electrolytic Reactor

    Science.gov (United States)

    Alireza Shirvanian, Pezhman; Calo, Joseph

    2002-08-01

    An Eulerian model is presented that has been developed to describe the hydrodynamics, mass transfer, and metal ion reduction mass transfer in a cylindrical, spouted bed electrolytic reactor. Appropriate boundary conditions are derived from kinetic theory and reaction kinetics for the hydrodynamics and mass transfer and reaction on the cathodic conical bottom of the reactor, respectively. This study was undertaken as a part of a project focused on the development of a Spouted Bed Electrolytic Reactor (SBER) for metals recovery. The results presented here include the effect of particle loading, inlet jet velocity, Solution pH, and temperature on void fraction distribution, pressure drop, particles recirculation rate, and metal recovery rate.

  10. Rupture safety for nuclear reactor pressure vessels

    International Nuclear Information System (INIS)

    This safety device for pressure vessels with cooling water inlet and outlet supports is to catch flying parts in the case of a rupture and to convert their energy into forming work without rupturing itself. A steel cladding is used for this purpose which surrounds the lower part of the pressure vessel as protective container like a pot, right up to the coolant supports. In order to keep the possible acceleration paths of the rupture pieces as small as possible, the gap between the two vessels is limited to a small tolerance to compensate for the differences in thermal expansion. In order to take up the compensating pressure after rupture of the reactor pressure vessel, the cylindrical part of the protective vessel requires double wall thickness like the concave floor. The cylindrical part is thus cladded by a cylindrical protective ring of the same wall thickness or by a multilayer sheet cladding which can be easily fabricated, transported and assembled. The cylindrical and concave part of the inner protective vessel have uniform wall thickness. This hence ensures that the elastic form changing is uniformly distributed over the height of the protective vessel. (HP)

  11. Theoretical analysis of nuclear reactors (Phase I), I-V, Part V, Determining the fine flux distribution

    International Nuclear Information System (INIS)

    Mono energetic neutron transport equation was solved by Carlson numerical method in cylindrical geometry. Sn code was developed for the digital computer ZUSE Z23. Neutron flux distribution was determined for the RA reactor cell by applying S4 approximation. Reactor cell was treated as D2O-U-D2O system. Time of iteration was 185 s

  12. Novel spherical hohlraum with cylindrical laser entrance holes and shields

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ke [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zheng, Wudi [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2014-09-15

    Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums.

  13. Optical testing of cylindrical surfaces with computer-generated holograms

    Science.gov (United States)

    Wang, Wei; Guo, Pei-ji

    2013-08-01

    Increasing demands for highly accurate cylinders require more high-precision testing techniques. The existing methods of testing cylindrical surfaces can not ensure the highly-accuracy, efficiency, convenience and the overall cost. In order to acquire highly accurate cylindrical surfaces conveniently at a low cost, a new Fizeau interferometric optical testing utilizing CGH which is fabricated onto a wedge-shaped substrate is designed. In this test, a slit filter is placed in the center of the cylindrical curvature to filter out the undesired diffraction orders which occur when the beam hits the CGH. Meanwhile, the front side of the wedge-shaped substrate is as the reference flat, and the CGH is written onto the inclined surface, so that the real fringe pattern can not be affected by its reflected beam. Moreover, the design of cylindrical surfaces under test tilting and off-center relative to the diffraction surface of the CGH results that the required rays for interference can be obtained effectively from the pinhole filter in the interferometer. Furthermore, high-accuracy CGH in this test can be processed by conventional microlithography equipments. Corresponding to a cylindrical surface with 60mm in diameter and f-number of 1/7, the test has been successfully designed and optimized in Zemax whose testing accuracy is prior to 0.0019λ. Better interference pattern can be obtained because all the other disturbing rays image outside of aperture in a radius of 2mm. Experiment shows the method is efficient and predominant.

  14. Monolithic Cylindrical Fused Silica Resonators with High Q Factors.

    Science.gov (United States)

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 10⁵ (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  15. Compact Reactor

    International Nuclear Information System (INIS)

    Weyl's Gauge Principle of 1929 has been used to establish Weyl's Quantum Principle (WQP) that requires that the Weyl scale factor should be unity. It has been shown that the WQP requires the following: quantum mechanics must be used to determine system states; the electrostatic potential must be non-singular and quantified; interactions between particles with different electric charges (i.e. electron and proton) do not obey Newton's Third Law at sub-nuclear separations, and nuclear particles may be much different than expected using the standard model. The above WQP requirements lead to a potential fusion reactor wherein deuterium nuclei are preferentially fused into helium nuclei. Because the deuterium nuclei are preferentially fused into helium nuclei at temperatures and energies lower than specified by the standard model there is no harmful radiation as a byproduct of this fusion process. Therefore, a reactor using this reaction does not need any shielding to contain such radiation. The energy released from each reaction and the absence of shielding makes the deuterium-plus-deuterium-to-helium (DDH) reactor very compact when compared to other reactors, both fission and fusion types. Moreover, the potential energy output per reactor weight and the absence of harmful radiation makes the DDH reactor an ideal candidate for space power. The logic is summarized by which the WQP requires the above conditions that make the prediction of DDH possible. The details of the DDH reaction will be presented along with the specifics of why the DDH reactor may be made to cause two deuterium nuclei to preferentially fuse to a helium nucleus. The presentation will also indicate the calculations needed to predict the reactor temperature as a function of fuel loading, reactor size, and desired output and will include the progress achieved to date

  16. Photocatalytic Solar Tower Reactor for the Elimination of a Low Concentration of VOCs

    Directory of Open Access Journals (Sweden)

    Nobuaki Negishi

    2014-10-01

    Full Text Available We developed a photocatalytic solar tower reactor for the elimination of low concentrations of volatile organic compounds (VOCs typically emitted from small industrial establishments. The photocatalytic system can be installed in a narrow space, as the reactor is cylindrical-shaped. The photocatalytic reactor was placed vertically in the center of a cylindrical scattering mirror, and this vertical reactor was irradiated with scattered sunlight generated by the scattering mirror. About 5 ppm toluene vapor, used as representative VOC, was continuously photodegraded and converted to CO2 almost stoichiometrically under sunny conditions. Toluene removal depended only on the intensity of sunlight. The performance of the solar tower reactor did not decrease with half a year of operation, and the average toluene removal was 36% within this period.

  17. Experiments of cylindrical isentropic compression by ultrahigh magnetic field

    Science.gov (United States)

    Gu, Zhuowei; Zhou, Zhongyu; Zhang, Chunbo; Tang, Xiaosong; Tong, Yanjin; Zhao, Jianheng; Sun, Chengwei

    2015-09-01

    The high Explosive Magnetic Flux Implosion Compression Generator (EMFICG) is a kind of unique high energy density dynamic technique with characters like ultrahigh pressure and low temperature rising and could be suitable as a tool of cylindrical isentropic compression. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP) have developed EMFICG technique and realized cylindrical isentropic compression. In the experiments, a seed magnetic field of 5-6 Tesla were built first and compressed by a stainless steel liner which is driven by high explosive. The inner free surface velocity of sample was measured by PDV. The isentropic compression of a copper sample was verified and the isentropic pressure is over 100 GPa. The cylindrical isentropic compression process has been numerical simulated by 1D MHD code and the simulation results were compared with the experiments. Compared with the transitional X-ray flash radiograph measurement, this method will probably promote the data accuracy.

  18. Experiments of cylindrical isentropic compression by ultrahigh magnetic field

    Directory of Open Access Journals (Sweden)

    Gu Zhuowei

    2015-01-01

    Full Text Available The high Explosive Magnetic Flux Implosion Compression Generator (EMFICG is a kind of unique high energy density dynamic technique with characters like ultrahigh pressure and low temperature rising and could be suitable as a tool of cylindrical isentropic compression. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP have developed EMFICG technique and realized cylindrical isentropic compression. In the experiments, a seed magnetic field of 5–6 Tesla were built first and compressed by a stainless steel liner which is driven by high explosive. The inner free surface velocity of sample was measured by PDV. The isentropic compression of a copper sample was verified and the isentropic pressure is over 100 GPa. The cylindrical isentropic compression process has been numerical simulated by 1D MHD code and the simulation results were compared with the experiments. Compared with the transitional X-ray flash radiograph measurement, this method will probably promote the data accuracy.

  19. Numerical investigation on evolution of cylindrical cellular detonation

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; JIANG Zong-lin; HU Zong-min; HAN Gui-lai

    2008-01-01

    Cylindrical cellular detonation is numerically investigated by solving twodimensional reactive Euler equations with a finite volume method on a two-dimensional self-adaptive unstructured mesh.The one-step reversible chemical reaction model is applied to simplify the control parameters of chemical reaction.Numerical results demonstrate the evolution of cellular cell splitting of cylindrical cellular detonation explored in experimentas.Split of cellular structures shows different features in the near-field and far-field from the initiation zone.Variation of the local curvature is a key factor in the behavior of cell split of cylindrical cellular detonation in propagation.Numerical results show that split of cellular structures comes from the self-organization of transverse waves corresponding to the development of small disturbances along the detonation front related to detonation instability.

  20. 2DEG on a cylindrical shell with a screw dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Filgueiras, Cleverson, E-mail: cleversonfilgueiras@yahoo.com.br [Unidade Acadêmica de Física, Universidade Federal de Campina Grande, POB 10071, 58109-970, Campina Grande, Paraíba (Brazil); Departamento de Física (DFI), Universidade Federal de Lavras (UFLA), Caixa Postal 3037, 37200-000, Lavras, Minas Gerais (Brazil); Silva, Edilberto O., E-mail: edilbertoos@pq.cnpq.br [Departamento de Física, Universidade Federal do Maranhão, Campus Universitário do Bacanga, 65085-580, São Luís, Maranhão (Brazil)

    2015-09-25

    Highlights: • Electron gas on a cylindrical surface. • Quantum Hall effects. • Geometric potential induced by confinement. • Topological defect. - Abstract: A two dimensional electron gas on a cylindrical surface with a screw dislocation is considered. More precisely, we investigate how both the geometry and the deformed potential due to a lattice distortion affect the Landau levels of such system. The case showing the deformed potential can be thought in the context of 3D common semiconductors where the electrons are confined on a cylindrical shell. We will show that important quantitative differences exist due to this lattice distortion. For instance, the effective cyclotron frequency is diminished by the deformed potential, which in turn enhances the Hall conductivity.

  1. Determination of the Boltzmann Constant Using the Differential - Cylindrical Procedure

    CERN Document Server

    Feng, X J; Lin, H; Gillis, K A; Moldover, M R

    2015-01-01

    We report in this paper the progresses on the determination of the Boltzmann constant using the acoustic gas thermometer (AGT) of fixed-length cylindrical cavities. First, we present the comparison of the molar masses of pure argon gases through comparing speeds of sound of gases. The procedure is independent from the methodology by Gas Chromatography-Mass Spectrometry (GC-MS). The experimental results show good agreement between both methods. The comparison offers an independent inspection of the analytical results by GC-MS. Second, we present the principle of the novel differential-cylindrical procedure based on the AGT of two fixed-length cavities. The deletion mechanism for some major perturbations is analyzed for the new procedure. The experimental results of the differential-cylindrical procedure demonstrate some major improvements on the first, second acoustic and third virial coefficients, and the excess half-widths. The three acoustic virial coefficients agree well with the stated-of-the-art experime...

  2. Clinical outcomes with drug-eluting and bare-metal stents in patients with ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego;

    2013-01-01

    The authors investigated the relative safety and efficacy of different drug-eluting stents (DES) and bare metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) using a network meta-analysis....

  3. NEUTRONIC REACTOR

    Science.gov (United States)

    Anderson, H.L.

    1960-09-20

    A nuclear reactor is described comprising fissionable material dispersed in graphite blocks, helium filling the voids of the blocks and the spaces therebetween, and means other than the helium in thermal conductive contact with the graphite for removing heat.

  4. NUCLEAR REACTOR

    Science.gov (United States)

    Miller, H.I.; Smith, R.C.

    1958-01-21

    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  5. Nuclear reactors

    International Nuclear Information System (INIS)

    This draft chart contains graphical symbols from which the type of (nuclear) reactor can be seen. They will serve as illustrations for graphical sketches. Important features of the individual reactor types are marked out graphically. The user can combine these symbols to characterize a specific reactor type. The basic graphical symbol is a square with a point in the centre. Functional groups can be depicted for closer specification. If two functional groups are not clearly separated, this is symbolized by a dotted line or a channel. Supply and discharge lines for coolant, moderator and fuel are specified in accordance with DIN 2481 and can be further specified by additional symbols if necessary. The examples in the paper show several different reactor types. (orig./AK)

  6. Benthic metabolism and denitrification in a river reach: a comparison between vegetated and bare sediments

    Directory of Open Access Journals (Sweden)

    Pierluigi VIAROLI

    2009-02-01

    Full Text Available This study aims at comparing biogeochemical processes in a Vallisneria spiralis meadow and in unvegetated sediments in the upper reach of the Mincio River (Northern Italy. The main hypothesis of this work is that meadows of rooted macrophytes affect benthic metabolism, enhancing capacity to retain nutrients (assimilation and dissipate (denitrification nitrogen loadings. In order to highlight how plants affect benthic processes in the riverbed, oxygen, dissolved inorganic carbon (DIC, soluble reactive phosphorus (SRP and inorganic nitrogen fluxes, together with denitrification rates, were measured from February to November 2007 in intact cores collected from stands of V. spiralis and bare sediments. V. spiralis biomass, elemental composition and growth rates were concurrently measured. Macrophyte biomass ranged from 60 to 120 g m-2 (as dry matter; growth rates followed a seasonal pattern from 0.001 in winter up to 0.080 d-1 in summer. On an annual basis, the macrophyte meadow was autotrophic with net O2 production and dissolved inorganic carbon uptake, while the bare sediment was net heterotrophic. The concurrent N assimilation by macrophytes and losses through denitrification led to similar N uptake/dissipation rates, up to 2500 mmol m-2 y-1. Under the very high NO3 - concentrations of the Mincio River, the competition between primary production and denitrification processes was also avoided. A significant ammonium regeneration from sediments to the water column occurred in the V. spiralis meadow, where plant debris and particulate matter accumulated. Here, SRP was also released into the water column, whilst in the bare sediment SRP fluxes were close to zero. Overall, V. spiralis affected the benthic metabolism enhancing the ecosystem capacity to control nitrogen contamination. However, the actual N removal rates were not sufficient to mitigate the pollution discharge.

  7. Multifunctional reactors

    OpenAIRE

    Westerterp, K.R.

    1992-01-01

    Multifunctional reactors are single pieces of equipment in which, besides the reaction, other functions are carried out simultaneously. The other functions can be a heat, mass or momentum transfer operation and even another reaction. Multifunctional reactors are not new, but they have received much emphasis in research in the last decade. A survey is given of modern developments and the first successful applications on a large scale. It is explained why their application in many instances is ...

  8. NUCLEAR REACTOR

    Science.gov (United States)

    Anderson, C.R.

    1962-07-24

    A fluidized bed nuclear reactor and a method of operating such a reactor are described. In the design means are provided for flowing a liquid moderator upwardly through the center of a bed of pellets of a nentron-fissionable material at such a rate as to obtain particulate fluidization while constraining the lower pontion of the bed into a conical shape. A smooth circulation of particles rising in the center and falling at the outside of the bed is thereby established. (AEC)

  9. Nuclear reactor

    International Nuclear Information System (INIS)

    In order to reduce neutron embrittlement of the pressue vessel of an LWR, blanked off elements are fitted at the edge of the reactor core, with the same dimensions as the fuel elements. They are parallel to each other, and to the edge of the reactor taking the place of fuel rods, and are plates of neutron-absorbing material (stainless steel, boron steel, borated Al). (HP)

  10. Breeder reactors

    International Nuclear Information System (INIS)

    The reasons for the development of fast reactors are briefly reviewed (a propitious neutron balance oriented towards a maximum uranium burnup) and its special requirements (cooling, fissile material density and reprocessing) discussed. The three stages in the French program of fast reactor development are outlined with Rapsodie at Cadarache, Phenix at Marcoule, and Super Phenix at Creys-Malville. The more specific features of the program of research and development are emphasized: kinetics and the core, the fuel and the components

  11. Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Charles Y., E-mail: charles.kim@duke.edu; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P. [Duke University Medical Center, Division of Vascular and Interventional Radiology (United States)

    2012-08-15

    Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

  12. Space demostration of bare electrodynamic tape-tether technology on the sounding rocket S520-25

    OpenAIRE

    Fujii, Hironori; Watanabe, Takeo; Sahara, Hironori; Kojima, Hirohisa; Takehara, Shoichiro; Yamagiwa, Yoshiki; Sasaki, Susumu; Abe, Takumi; Tanaka, Koji; Oyama, Khoichiro; Jhonson, Les; Khazanov, V.; Sanmartín Losada, Juan Ramón; Charro, Mario; Kruijff, Michiel

    2011-01-01

    A spaceflight validation of bare electro dynamic tape tether technology was conducted. A S520-25 sounding rocket was launched successfully at 05:00am on 31 August 2010 and successfully deployed 132.6m of tape tether over 120 seconds in a ballistic flight. The electrodynamic performance of the bare tape tether employed as an atmospheric probe was measured. Flight results are introduced through the present progressive report of the demonstration and the results of flight experiment are ex...

  13. T-REX: Bare electro-dynamic tape-tether technology experimetn on sounding rocket S520

    OpenAIRE

    Watanabe, Takeo; Fujii, Hironori; Kusagaya, Tairo; Sahara, Hironori; Kojima, Hirohisa; Takehara, Shoichiro; Yamagiwa, Yoshiki; Sasaki, Susumu; Abe, Takumi; Tanaka, Koji; Oyama, Khoichiro; Ebinuma, Takuji; Johson, Les; Khazanov, George; Sanmartín Losada, Juan Ramón

    2012-01-01

    The project to verify the performance of space tether technology was successfully demonstrated by the launch of the sounding rocket S520 the 25tu. The project is the space demonstration of science and engineering technologies of a bare tape electrodynamic tether (EDT) in the international campaign between Japan, USA, Europe and Australia. Method of "Inverse ORIGAMI (Tape tether folding)" was employed in order to deploy the bare tape EDT in a short period time of the suborbital flight. The ...

  14. Azimuthally-dependent Finite Element Solution to the Cylindrical Resonator

    Science.gov (United States)

    Osegueda, R.; Pierluissi, J.; Gil, L.; Revilla, A.; Villalva, G.; Dick, G.; Wang, D. SantiagoR.

    1994-01-01

    The cylindrical cavity resonator loaded with an anisotropic dielectric is analyzed as a two-dimensional problem using a finite element approach that assumes sinusoidal dependence in azimuth. This methodology allows the first finite element treatment of the technically important case of a resonator containing a sapphire element with a cylindrically aligned c axis. Second order trial functions together with quadrilateral elements are adopted in the calculations. The method was validated through comparisons with the analytical solutions for the hollow metal cavity and a coaxial cavity, as well as through measurements on a shielded sapphire resonator.

  15. Gravitational collapse of a cylindrical null shell in vacuum

    Directory of Open Access Journals (Sweden)

    S. Khakshournia

    2008-03-01

    Full Text Available   Barrabès-Israel null shell formalism is used to study the gravitational collapse of a thin cylindrical null shell in vacuum. In general the lightlike matter shell whose history coincides with a null hypersurface is characterized by a surface energy density. In addition, a gravitational impulsive wave is present on this null hypersurface whose generators admit both the shear and expansion. In the case of imposing the cylindrical flatness the surface energy-momentum tensor of the matter shell on the null hypersurface vanishes and the null hyper- surface is just the history of the gravitational wave .

  16. Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium

    Science.gov (United States)

    Xiong, Hao; Si, Liu-Gang; Yang, Xiaoxue; Wu, Ying

    2015-06-01

    A simple but highly efficient approach for dealing with the problem of cylindrical electromagnetic waves propagation in a nonlinear medium is proposed based on an exact solution proposed recently. We derive an analytical explicit formula, which exhibiting rich interesting nonlinear effects, to describe the propagation of any amount of cylindrical electromagnetic waves in a nonlinear medium. The results obtained by using the present method are accurately concordant with the results of using traditional coupled-wave equations. As an example of application, we discuss how a third wave affects the sum- and difference-frequency generation of two waves propagation in the nonlinear medium.

  17. The magnetic properties of the hollow cylindrical ideal remanence magnet

    DEFF Research Database (Denmark)

    Bjørk, Rasmus

    2016-01-01

    We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived and the...... generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown...... to generate a field exactly twice as large as the equivalent ideal remanence magnet....

  18. Confined and interface phonons in combined cylindrical nanoheterosystem

    Directory of Open Access Journals (Sweden)

    O.M.Makhanets

    2006-01-01

    Full Text Available The spectra of all types of phonons existing in a complicated combined nanoheterosystem consisting of three cylindrical quantum dots embedded into the cylindrical quantum wire placed into vacuum are studied within the dielectric continuum model. It is shown that there are confined optical (LO and interface phonons of two types: top surface optical (TSO and side surface optical (SSO modes of vibration in such a nanosystem. The dependences of phonon energies on the quasiwave numbers and geometrical parameters of quantum dots are investigated and analysed.

  19. 2DEG on a cylindrical shell with a screw dislocation

    Science.gov (United States)

    Filgueiras, Cleverson; Silva, Edilberto O.

    2015-09-01

    A two dimensional electron gas on a cylindrical surface with a screw dislocation is considered. More precisely, we investigate how both the geometry and the deformed potential due to a lattice distortion affect the Landau levels of such system. The case showing the deformed potential can be thought in the context of 3D common semiconductors where the electrons are confined on a cylindrical shell. We will show that important quantitative differences exist due to this lattice distortion. For instance, the effective cyclotron frequency is diminished by the deformed potential, which in turn enhances the Hall conductivity.

  20. The Levitating Buddha: Constructing a Realistic Cylindrical Mirror Pseudo Image

    Science.gov (United States)

    Caussat, María Alicia; Rabal, Héctor; Muramatsu, Mikiya

    2006-10-01

    There are several interesting experiments involving image formation that can be easily implemented using mirrored foil, a very inexpensive material. When the foil is somewhat bent by holding its opposite edges and slightly pulling them together, cylindrical surfaces are generated. They behave as cylindrical mirrors, and circular or elliptical cross sections can be made. A project that can be easily built with the mirror foil is the generation of a pseudo image that is so compelling in its apparent reality that it can easily be taken to be the object itself.

  1. Buckling localization in a cylindrical panel under axial compression

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    Localization of an initially periodic buckling pattern is investigated for an axially compressed elastic-plastic cylindrical panel of the type occurring between axial stiffeners on cylindrical shells. The phenomenon of buckling localization and its analogy with plastic flow localization in tensile......, but where subsequently the load starts to increase again, it is found that near the local load minimum, the buckling pattern switches back to a periodic type of pattern. The inelastic material behavior of the panel is described in terms of J(2) corner theory, which avoids the sometimes unrealistically...

  2. Computer simulations of cylindrical current discharge driven spherical implosions

    International Nuclear Information System (INIS)

    The authors present one and two dimensional magnetohydrodynamic simulations of cylindrical and quasi-spherical current discharge driven spherical implosions. Analytic results imply that by properly compressing a pre-heated (∼ 1--5 eV), high sound speed working fluid, a centered target may undergo spherical compression. The authors show this compression may be possible using properly shaped, i.e., quasi-spherical imploding liners. The authors contrast this implosion method with traditional cylindrical implosions and present arguments favoring one method over the other

  3. Superficial soil erosion assessment in agricultural land and bare land using 7Be fallout

    International Nuclear Information System (INIS)

    Geologic and hydrologic phenomenon monitoring presents great environmental and financial interest and several radioisotopes, natural and artificial, have been used for this purpose. The more used are 137Cs, 210Pb not supported and 7Be. In the present work, 7Be was used to determine the soil erosion in three areas: one with soy ploughed at the direction of the slope, one with it perpendicular to the slope and one in an area with bare soil. 7Be is a cosmogenic radionuclide, with half-life of 53.3 days, produced by spallation of oxygen and nitrogen by cosmic rays in the troposphere and stratosphere. 7Be deposition occurs by dry and wet deposition, although wet deposition contributed by 95%. This can be verified through the measures of the 7Be inventory correlated with the precipitation, which resulted in a good linear adjustment. The experimental set up consisted of two HPGe detectors: one with 66% of relative efficiency and one with 10% of relative efficiency, both detectors coupled to standard gamma ray spectrometry nuclear electronic chain. Soil samples were packed in 1 liter Marinelli beckers. Sampling was accomplished until the depth where 7Be was present and it was possible to verify that its penetration in the soils could be very well adjusted by an exponential type function. The maximum beryllium-7 penetration in the bare soil without sign of soil erosion was 3 cm, that is, beryllium-7 is a useful tool as tracer for superficial soil erosion determination. The constant of mass relaxation h0 was determined as 4.71 ± 0.36, result that is in agreement with other works in the international literature. It was verified that when the soy is ploughed perpendicular to the slope, the soil redistribution rate is smaller, resulting in economic advantage. The bare soil is very exposed to the erosion, because does not exist any barrier to contain the soil that flows at the direction of the slope, such fact was verified in this work, where it was determined that the bare

  4. Universal, geometry-driven hydrophobic behaviour of bare metal nanowire clusters

    International Nuclear Information System (INIS)

    A parallel array of isolated metal nanowires is expected to be hydrophilic. We show, however, that a clustering of such nanowires brought about by vacuum drying produces a 'dual-scale roughness' and confers a strongly hydrophobic property to the surface. The mean size of the nanowire clusters as well as the contact angle are both found to be related to the wire length, and the critical wire length above which the surface becomes hydrophobic is ∼10 μm. Surface roughness is generally known to enhance water-repellent properties, but this is the first report of roughness-induced hydrophobicity on a bare (uncoated) metallic surface

  5. A Simulating Experiment in the Process of Soil Erosion on Bare Land in Mt. Tanakami

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; HU Ke; WANG Xikui; Akitsu KIMOTO; Takahisa MIZUYAMA

    2001-01-01

    In order to understand the process of surface erosion and acquire basic data of conditions on hillslope without vege tation, a sprinkling experiment is conducted on a bare slope in Mt. Tanakami in the central part of Japan. Based on the mea surements of runoff, mean soil erosion depth, and sediment yield, etc. , the results suggest the following characteristics in the process of surface erosion in the experimental area. (1) The occurrence of sediment discharge is interrupted; (2) Surface runoff is a saturated overland flow; (3) The mean soil erosion depth is thick compared with other areas in Mt. Tanakami;(4) Sediment discharge process is detachment- limited.

  6. Use of TerraSAR-X data to retrieve soil moisture over bare soil agricultural fields

    OpenAIRE

    Baghdadi, N.; Aubert, M.; Zribi, M.

    2012-01-01

    The retrieval of the bare soil moisture content from TerraSAR-X data is discussed using empirical approaches. Two cases were evaluated: 1) one image at low or high incidence angle and 2) two images, one at low incidence and one at high incidence. This study shows by using three databases collected between 2008 and 2010 over two study sites in France (Orgeval and Villamblain) that TerraSAR-X is a good remote sensing tool for the retrieving of surface soilmoisture with accuracy of about 3% (rms...

  7. Safety and efficacy of everolimus-eluting stents for bare-metal in-stent restenosis

    Energy Technology Data Exchange (ETDEWEB)

    Ota, Hideaki [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Mahmoudi, Michael [University of Surrey, Guildford Road, Surrey, GU2-7XH (United Kingdom); Torguson, Rebecca; Satler, Lowell F.; Suddath, William O.; Pichard, Augusto D. [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Waksman, Ron, E-mail: ron.waksman@medstar.net [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States)

    2015-04-15

    Objective: The aim of this study was to compare the safety and efficacy of the everolimus-eluting stents (EES) with the paclitaxel-eluting stent (PES) and sirolimus-eluting stent (SES) for the treatment of bare-metal in-stent restenosis. Background: The optimal treatment for bare-metal in-stent restenosis remains controversial. Methods: The study cohort comprised 322 consecutive patients (543 lesions) who presented with bare-metal in-stent restenosis to our institution and underwent coronary artery stent implantation with EES (114 patients; 181 lesions), PES (65 patients; 116 lesions) and SES (143 patients; 246 lesions). The analyzed clinical parameters were the 1-year rates of death, Q-wave myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), definite stent thrombosis (ST) and major adverse cardiac events (MACE) defined as the composite of death, MI, or TLR at 1-year. Results: The three groups were well matched for the conventional risk factors except for age and chronic kidney disease. The 1-year analyzed clinical parameters were similar in the three groups: death (EES = 3.5%, PES = 4.6%, SES = 4.2%; p = 0.94), MI (EES = 3.5%, PES = 6.3%, SES = 2.1%; p = 0.31), TLR (EES = 9.8%, PES = 9.5%, SES = 5.7%; p = 0.42), TVR (EES = 14.3%, PES = 11.1%, SES = 11.3%; p = 0.74), definite ST (EES = 0.9%, PES = 3.1%, SES = 3.5%; p = 0.38) and MACE (EES = 14.0%, PES = 15.4%, SES = 10.5%; p = 0.54). Male gender (hazard ratio = 0.47; 95% confidence interval = 0.25–0.88) and number of treated lesions (hazard ratio = 1.47; 95% confidence interval = 1.06–2.05) were found to be independent predictors of MACE. Conclusion: The results of the present study indicate that EES may provide similar safety and efficacy as first generation DES for the treatment of patients presenting with bare-metal in-stent restenosis.

  8. A case report of very late stent thrombosis after bare-metal stent implantation

    Directory of Open Access Journals (Sweden)

    Mustafa Adem Tatlısu

    2014-03-01

    Full Text Available Stent thrombosis is undesirable complication after percutaneous coronary interventions (PCI, despite contemporary concepts of stents and antiplatelet therapy. Stent thrombosis (ST is defined by the Academic Research Concortium as: early (1 year. Risk of very late stent thrombosis is considerably higher in patients with drug-eluting stents (DES, owing to delayed endothelialization. There are several cases very late ST after bare-metal stent (BMS implantation. Our patient presented with ST-elevation myocardial infarction on account of BMS thrombosis 14 years after the implantation.

  9. KSU project: CRYEBIS for producing slow, bare, heavy-ion beams

    International Nuclear Information System (INIS)

    The design and construction of a cryogenic electron beam ion source is in progress at Kansas State University. In about two years this source should produce high yields of bare and few-electron argon ions with low kinetic energies (approx.keV--MeV). The design is similar to the latest French designs ]CRYEBIS II [J. Arianer, C. Goldstein, H. Laurent, and M. Malard, IEEE Trans. Nucl. Sci. NS-30, 2737 (1983)] and DIONE [B. Gastineau, J. Faure, and A. Courtois, Nucl. Instrum. Methods B9, 538 (1985)

  10. Introducing the notion of bare and effective mass via Newton's second law of motion

    International Nuclear Information System (INIS)

    The concepts of bare and effective mass are widely used within modern physics. Their meaning is discussed in advanced undergraduate and graduate courses such as solid state physics, nuclear physics and quantum field theory. Here I discuss how these concepts may be introduced together with the discussion of Newton's second law of motion. The setting up of simple equations for the effective mass will allow instructors to discuss how external parameters, such as the temperature, influence this quantity. By expressing this type of equation as a power series one may also discuss perturbation theory and introduce Feynman diagrams

  11. Collision of Bare Ion Si14+ with the Same Z Slow-atom Si

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We present the collision of bare ion Si14+ with the same Z slow-atom Si. It is shown that the cold-atom collisions are sensitive to the potential. In this paper, we present the cross sectiond for the most important transition from the 3p13d1 and 3p14d1 excited states. It is seen that there are large cross sections when the angle is larger than 80 degrees. With increasing energy, the cross section becomes decresasingly flat.PACS numbers:34.70.+e, 32.80. Fb

  12. Coarse mesh transport method for whole-core neutronics analysis in cylindrical geometry

    International Nuclear Information System (INIS)

    In this paper, a coarse mesh transport (Comet) method has been developed to predict neutronics behaviors in reactor cores with 2-dimensional cylindrical (r, θ) geometry. Based on neutron balance in each coarse mesh, the outgoing partial current (or flux) from a coarse mesh is calculated as the sum of the local responses to all incoming partial currents/fluxes via pre-computed incident response expansion functions. These local functions essentially represents the probabilities that the incoming neutrons and their progenies contributes to the quantities of interest such as outgoing partial currents/fluxes and fission densities. The Comet code was benchmark against the Monte Carlo Code MCNP in a test problem representative of a simplified Pebble Bed reactor core in (r, θ) geometry, consisting of an inner reflector, an annular fuel region, and a controlled outer reflector. With 4th order expansion in space and 2nd expansion order in the polar and azimuthal angles, the Comet calculation agrees very well with the MCNP reference solution. (Author)

  13. Experimental and numerical study of the strong interaction between wakes of cylindrical obstacles

    International Nuclear Information System (INIS)

    In the context of thermal-hydraulics of nuclear reactors, strong interaction between wakes is encountered in the bottom of reactor vessels where control and measurement rods of variable size and disposition interact with the overall wakes generated in these flow zones. This study deals with the strong interaction between two wakes developed downstream of two parallel cylinders with a small spacing. The analysis focusses on the effect of the Reynolds regime which controls the equilibrium between the inertia and viscosity forces of the fluid and influences the large scale behaviour of the flow with the development of hydrodynamic instabilities and turbulence. The document is organized as follows: the characteristic phenomena of wakes formation downstream of cylindrical obstacles are recalled in the first chapter (single cylinder, interaction between two tubes, case of a bundle of tubes perpendicular to the flow). The experimental setup (hydraulic loop, velocity and pressure measurement instrumentation) and the statistical procedures applied to the signals measured are detailed in chapters 2 and 3. Chapter 4 is devoted to the experimental study of the strong interaction between two tubes. Laser Doppler velocity measurements in the wakes close to cylinders and pressure measurements performed on tube walls are reported in this chapter. In chapter 5, a 2-D numerical simulation of two typical cases of interaction (Re = 1000 and Re = 5000) is performed. In the last chapter, a more complex application of strong interactions inside and downstream of a bunch of staggered tubes is analyzed experimentally for equivalent Reynolds regimes. (J.S.)

  14. Management of ageing research reactors in the Vinca Institute

    International Nuclear Information System (INIS)

    Nuclear research reactors in the Institute of nuclear sciences Vinca (former 'Boris Kidric'), built in late fifties, were among the first ones in the Southeast Europe. The RB reactor is constructed by Yugoslav scientists and put in operation at the end of April 1958 as a bare critical natural U-heavy water system. The RA reactor a 6.5 MW heavy water reactor, designed in ex-USSR, began operation in 1959 as one of research reactors with better characteristics in the world. Both reactors were built according to the national plan of development of nuclear energy in the country. Decision about future of the RA reactor in the Vinca Institute is not brought yet. Main improvements in operation and safety, and ageing management of the Vinca reactors in the past years are given in this paper. They are results of long experience acquired in management of the reactors operation, maintenance, testing, ageing of equipment and systems and development and application of new contemporary safety criteria

  15. Performance of bare high-purity germanium detectors in liquid argon for the GERDA experiment

    CERN Document Server

    Heider, Marik Barnabé; Chkvorets, Oleg; Di Vacri, Assunta; Gusev, Konstantin; Schönert, Stefan; Shirchenko, Mark

    2008-01-01

    The GERmanium Detector Array, GERDA, will search for neutrinoless double beta decay in 76Ge at the National Gran Sasso Laboratory of the INFN. Bare high-purity germanium detectors enriched in 76Ge will be submerged in liquid argon serving simultaneously as a shield against external radioactivity and as a cooling medium. In GERDA Phase-I, reprocessed enriched-Ge detectors, which were previously operated by the Heidelberg-Moscow and IGEX collaborations, will be redeployed. Before operating the enriched detectors, tests are performed with non-enriched bare HPGe detectors in the GERDA underground Detector Laboratory to test the Phase-I detector assembly, the detector handling protocols, the refurbishment technology and to study the long-term stability in liquid argon. The leakage currents in liquid argon and liquid nitrogen have been extensively studied under varying gamma irradiation conditions. In total three non-enriched high-purity p-type prototype germanium detectors have been operated successfully. The dete...

  16. Estimation of evaporation and drainage losses from two bare soils in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Mehmet Aydin

    2012-01-01

    Full Text Available In this study, evaporation, drainage rates and water storage of two bare soils in the east (Batticaloa and west (Puttalam regions of Sri Lanka, were simulated using the E-DiGOR model. Daily simulations were carried out for each of the years during the periods of 1978 to 1987 in Batticaloa and 1998 to 2007 in Puttalam using standard climate data. The soils in the locations were predominantly sandy loam and/or sandy clay loam. Grass reference evapotranspiration and potential soil evaporation were higher, whereas actual soil evaporation was lower during the dry seasons. The 10-year average annual reference evapotranspiration and potential soil evaporation were 2069.3 mm and 1814.1 mm in Batticaloa, and 1908.8 mm and 1714.5 mm in Puttalam, respectively. Aridity index (precipitation/reference evapotranspiration was 0.685 for Batticaloa and 0.606 for Puttalam. The actual evaporation from bare soil varied between 463.1—725.0 mm in Batticaloa and 543.6—646.3 mm in Puttalam. Annual drainage rates below 150 cm soil depth ranged from 321.7 to 1581.2 mm in Batticaloa and from 346.7 to 957.0 mm in Puttalam. Soil water storage changed daily depending on the intensity and frequency of rainfall events and on evaporation rates.

  17. Photo-physical properties enhancement of bare and core-shell quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Mumin, Md Abdul, E-mail: pcharpentier@eng.uwo.ca; Akhter, Kazi Farida, E-mail: pcharpentier@eng.uwo.ca; Charpentier, Paul A., E-mail: pcharpentier@eng.uwo.ca [Chemical and Biochemical Engineering, Western University, London Ontario (Canada)

    2014-03-31

    Semiconductor nanocrystals (NCs) (also known as quantum dots, QDs) have attracted immense attention for their size-tunable optical properties that makes them impressive candidates for solar cells, light emitting devices, lasers, as well as biomedical imaging. However monodispersity, high and consistent photoluminescence, photostability, and biocompatibility are still major challenges. This work focuses on optimizing the photophysical properties and biocompatibility of QDs by forming core-shell nanostructures and their encapsulation by a carrier. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm sizes were synthesized using a facile approach based on pyrolysis of the single molecule precursors. After capping the CdS QDs with a thin layer of ZnS to reduce toxicity, the photoluminescence and photostability of the core-shell QDs was significantly enhanced. To make both the bare and core/shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interaction. This encapsulation enhanced the quantum yield and photostability compared to the bare QDs by providing much stronger resistance to oxidation and Oswald ripening of QDs. Encapsulation also improved biocompatibility of QDs that was evaluated with human umbilical vein endothelial cell lines (HUVEC)

  18. Imparting Barely Visible Impact Damage to a Stitched Composite Large-Scale Pressure Box

    Science.gov (United States)

    Przekop, Adam; Lovejoy, Andrew E.

    2016-01-01

    The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration, which has been a focus of the NASA Environmentally Responsible Aviation Project. The NASA-Boeing structural development for the HWB aircraft culminated in testing of the multi-bay box, which is an 80%-scale representation of the pressurized center-body section. This structure was tested in the NASA Langley Research Center Combined Loads Test System facility. As part of this testing, barely visible impact damage was imparted to the interior and exterior of the test article to demonstrate compliance with a condition representative of the requirements for Category 1 damaged composite structure as defined by the Federal Aviation Regulations. Interior impacts were imparted using an existing spring-loaded impactor, while the exterior impacts were imparted using a newly designed, gravity-driven impactor. This paper describes the impacts to the test article, and the design of the gravitydriven guided-weight impactor. The guided-weight impactor proved to be a very reliable method to impart barely visible impact damage in locations which are not easily accessible for a traditional drop-weight impactor, while at the same time having the capability to be highly configurable for use on other aircraft structures.

  19. Ice Formation via Deposition Mode Nucleation on Bare and Alcohol-covered Graphite Surfaces

    CERN Document Server

    Kong, Xiangrui; Thomson, Erik S; Pettersson, Jan B C

    2013-01-01

    Deposition of water on aerosol particles contributes to ice cloud formation in the atmosphere with implications for the water cycle and climate on Earth. The heterogeneous ice nucleation process is influenced by physico-chemical properties of the substrate, but the mechanisms remain incompletely understood. Here, we report on ice formation on bare and alcohol-covered graphite at temperatures from 175 to 213 K, probed by elastic helium and light scattering. Water has a low wettability on bare and butanol-covered graphite resulting in the growth of rough ice surfaces. In contrast, pre-adsorbed methanol provides hydrophilic surface sites and results in the formation of smooth crystalline ice; an effect that is pronounced also for sub-monolayer methanol coverages. The alcohols primarily reside at the ice surface and at the ice-graphite interface with a minor fraction being incorporated into the growing ice structures. Methanol has no observable effect on gas/solid water vapor exchange whereas butanol acts as a tr...

  20. Oralloy (93.2 235U) Bare Metal Annuli And Disks

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, Andrew John [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    A multitude of critical experiments with highly enriched uranium metal were conducted in the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. These experiments served to evaluate the storage, casting, and handling limits for the Y-12 Plant while also providing data for verification of different calculation methods and associated cross-sections for nuclear criticality safety applications. These included both solid cylinders and annuli of various diameters, interacting cylinders of various diameters, parallelepipeds, and reflected cylinders and annuli. The experiments described here involve a series of delayed critical stacks of bare oralloy HEU annuli and disks. Three of these experiments consist of stacking bare HEU annuli of varying diameters to obtain critical configurations. These annuli have nominal inner and outer diameters (ID/OD) including: 7 inches (") ID – 9" OD, 9" ID – 11" OD, 11" ID – 13" OD, and 13? ID – 15" OD. The nominal heights range from 0.125" to 1.5". The three experiments themselves range from 7" – 13", 7" – 15", and 9" – 15" in diameter, respectively. The fourth experiment ranges from 7" – 11", and along with different annuli, it also includes an 11" disk and several 7" diameter disks. All four delayed critical experiments were configured and evaluated by J. T. Mihalczo, J. J. Lynn, and D. E. McCarty from December of 1962 to February 1963 with additional information in their corresponding logbook.

  1. A simple model for retrieving bare soil moisture from radar-scattering coefficients

    International Nuclear Information System (INIS)

    A simple algorithm based on a rough surface scattering model was developed to invert the bare soil moisture content from active microwave remote sensing data. In the algorithm development, a frequency mixing model was used to relate soil moisture to the dielectric constant. In particular, the Integral Equation Model (IEM) was used over a wide range of surface roughness and radar frequencies. To derive the algorithm, a sensitivity analysis was performed using a Monte Carlo simulation to study the effects of surface parameters, including height variance, correlation length, and dielectric constant. Because radar return is inherently dependent on both moisture content and surface roughness, the purpose of the sensitivity testing was to select the proper radar parameters so as to optimally decouple these two factors, in an attempt to minimize the effects of one while the other was observed. As a result, the optimal radar parameter ranges can be chosen for the purpose of soil moisture content inversion. One thousand samples were then generated with the IEM model followed by multivariate linear regression analysis to obtain an empirical soil moisture model. Numerical comparisons were made to illustrate the inversion performance using experimental measurements. Results indicate that the present algorithm is simple and accurate, and can be a useful tool for the remote sensing of bare soil surfaces. (author)

  2. Matching the BtA line to the bare-AGS (Part 1)

    Energy Technology Data Exchange (ETDEWEB)

    Tsoupas,N.; Glenn, J. W.; Huan, H.; MacKay, W. W.; Raparia, D.; Zeno, K.

    2008-11-01

    The Booster to AGS (BtA) transfer line [Ref for BtA line] transports the beam bunches from the AGS-Booster to the AGS synchrotron, and also matches the beam parameters ({beta}{sub x,y}, {alpha}{sub x,y}) and dispersion functions ({eta}{sub x,y}, {eta}{prime}{sub x,y}) of the transported beam to the corresponding quantities of the circulating beam in AGS, at the AGS injection point. In this technical note we describe in details, the calculations of the matching procedure of the BtA line to the bare-AGS, and provide magnet settings for the MAD-model of the BtA transfer line which is 'matched' to the bare-AGS. In a separate but more concise technical note (Part II) we will present results on the beam optics of the BtA beam line which is 'matched' to the AGS with two helical snakes.

  3. Microwave remote sensing of soil moisture content over bare and vegetated fields

    Science.gov (United States)

    Wang, J. R.; Shiue, J. C.; Mcmurtrey, J. E., III

    1980-01-01

    Remote measurements of soil moisture contents over bare fields and fields covered with orchard grass, corn, and soybean were made during October 1979 with 1.4 GHz and 5 GHz microwave radiometers mounted on a truck. Ground truth of soil moisture content, ambient air, and soil temperatures was acquired concurrently with the radiometric measurements. The biomass of the vegetation was sampled about once a week. The measured brightness temperatures over bare fields were compared with those of radiative transfer model calculations using as inputs the acquired soil moisture and temperature data with appropriate values of dielectric constants for soil-water mixtures. Good agreement was found between the calculated and the measured results over 10-70 deg incident angles. The presence of vegetation was found to reduce the sensitivity of soil moisture sensing. At 1.4 GHz the sensitivity reduction ranged from approximately 20% for 10-cm tall grassland to over 60% for the dense soybean field. At 5 GHz the corresponding reduction in sensitivity ranged from approximately 70 to approximately 90%.

  4. Probing the Surfaces of Interstellar Dust Grains: The Adsorption of CO at Bare Grain Surfaces

    CERN Document Server

    Fraser, H J; Pontoppidan, K M; Van Dishoeck, A G; Fraser, Helen J.; Bisschop, Suzanne E.; Pontoppidan, Klaus M.; Dishoeck, Alexander G.G.M. Tielens & Ewine F. van

    2004-01-01

    A solid-state feature was detected at around 2175 cm-1 towards 30 embedded young stellar objects in spectra obtained using the ESO VLT-ISAAC. We present results from laboratory studies of CO adsorbed at the surface of Zeolite wafers, where absorption bands were detected at 2177 and 2168 cm-1 (corresponding to CO chemisorbed at the Zeolite surface), and 2130 cm-1 (corresponding to CO physisorbed at the Zeolite surface), providing an excellent match to the observational data. We propose that the main carrier of the 2175-band is CO chemisorbed at bare surfaces of dust grains in the interstellar medium. This result provides the first direct evidence that gas-surface interactions do not have to result in the formation of ice mantles on interstellar dust. The strength of the 2175-band is estimated to be ~ 4 x 10-19 cm molecule-1. The abundance of CO adsorbed at bare grain surfaces ranges from 0.06 to 0.16 relative to H2O ice, which is, at most, half of the abundance (relative to H2O ice) of CO residing in H2O-domin...

  5. RX J1856.5-3754 Bare Quark Star or Naked Neutron Star ?

    CERN Document Server

    Zane, S; Drake, J J

    2003-01-01

    Recent Chandra observations have shown that the soft X-ray spectrum from the isolated neutron star RX J1856.5-3754 is featureless and best fitted by a blackbody, in contrast with the predictions of current neutron star atmospheric models. The star distance (~120-140 pc) implies a radiation radius of at most \\~5-6 km, too small for any neutron star equation of state. Proposed explanations for such a small radius include a reduced X-ray emitting region (as a polar cap), or the presence of a more compact object, as a bare quark/strange star. However, both interpretations rely on the presumption that the quark star or the cap radiates a pure blackbody spectrum, and no justification for this assumption has been presented yet. Here we discuss an alternative possibility. Cool neutron stars (T 10^13 G) may suffer a phase transition in the outermost layers. The neutron star is then left bare of the gaseous atmosphere. We computed spectra from naked neutron stars with a surface Fe composition. Depending on B, we found...

  6. Trajectories of water table recovery following the re-vegetation of bare peat

    Science.gov (United States)

    Shuttleworth, Emma; Evans, Martin; Allott, Tim; Maskill, Rachael; Pilkington, Michael; Walker, Jonathan

    2016-04-01

    The hydrological status of blanket peat influences a wide range of peatland functions, such as runoff generation, water quality, vegetation distribution, and rates of carbon sequestration. The UK supports 15% of the world's blanket peat cover, but much of this vital resource is significantly degraded, impacted by industrial pollution, overgrazing, wildfire, and climatic shifts. These pressures have produced a unique landscape characterised by severe gully erosion and extensive areas of bare peat. This in turn has led water tables to become substantially drawn down, impacting peatland function and limiting the resilience of these landscapes to future changes in climate. The restoration of eroding UK peatlands is a major conservation concern, and landscape-scale interventions through the re-vegetation of bare peat is becoming increasingly extensive in areas of upland Britain. Water table is the primary physical parameter considered in the monitoring of many peatland restoration projects, and there is a wealth of data on individual monitoring programmes which indicates that re-vegetation significantly raises water tables. This paper draws on data from multiple restoration projects carried out by the Moors for the Future Partnership in the Southern Pennines, UK, covering a range of stages in the erosion-restoration continuum, to assess the trajectories of water table recovery following re-vegetation. This will allow us to generate projections of future water table recovery, which will be of benefit to land managers and conservation organisations to inform future restoration initiatives.

  7. Different toxicity mechanisms between bare and polymer-coated copper oxide nanoparticles in Lemna gibba

    International Nuclear Information System (INIS)

    In this report, we investigated how the presence of a polymer shell (poly(styrene-co-butyl acrylate) alters the toxicity of CuO NPs in Lemna gibba. Based on total Cu concentration, core–shell CuO NPs were 10 times more toxic than CuO NPs, inducing a 50% decrease of growth rate at 0.4 g l−1 after 48-h of exposure while a concentration of 4.5 g l−1 was required for CuO NPs for a similar effect. Toxicity of CuO NPs was mainly due to NPs solubilization in the media. Based on the accumulated copper content in the plants, core–shell CuO NPs induced 4 times more reactive oxygen species compared to CuO NPs and copper sulfate, indicating that the presence of the polymer shell changed the toxic effect induced in L. gibba. This effect could not be attributed to the polymer alone and reveals that surface modification may change the nature of NPs toxicity. -- Highlights: • Bare and polymer-coated CuO nanoparticles were toxic to Lemna gibba. • Toxicity of bare CuO was mainly due to solubilized soluble copper. • Coated CuO accumulated inside the plants four times more. • Formation of reactive oxygen species was increased by polymer coating. • Coating of nanomaterials modifies mechanisms of action at cellular level. -- Polymer coating increases oxidative stress effect by core–shell CuO nanoparticles

  8. Similar Success Rates with Bivalirudin and Unfractionated Heparin in Bare-Metal Stent Implantation

    International Nuclear Information System (INIS)

    Background. Unfractionated heparin (UFH) is the traditional agent utilized during percutaneous peripheral interventions (PPIs) despite its well-known limitations. Bivalirudin, a thrombin-specific anticoagulant, overcomes many of the limitations of UFH and has consistently demonstrated comparable efficacy with significantly fewer bleeding complications. The purpose of this study was to compare procedural success in patients undergoing bare-metal stent implantation for atherosclerotic blockage of the renal, iliac, and femoral arteries and receiving either bivalirudin (0.75 mg/kg bolus/1.75 mg/kg/hr infusion) or UFH (50-70 U/kg/hr bolus) as the primary anticoagulant. Methods. This study was an open-label, nonrandomized retrospective registry with the primary endpoint of procedural success. Secondary endpoints included incidence of: death, myocardial infarction (MI), urgent revascularization, amputation, and major and minor bleeding. Results. One hundred and five consecutive patients were enrolled (bivalirudin = 53; heparin = 52). Baseline demographics were comparable between groups. Patients were pretreated with clopidogrel (approx. 71%) and aspirin (approx. 79%). Procedural success was achieved in 97% and 96% of patients in the bivalirudin- and heparin-treated groups, respectively. Event rates were low and similar between groups. Conclusion. Bivalirudin maintained an equal rate of procedural success in this cohort without sacrificing patient safety. Results of this study add to the growing body of evidence supporting the safety and efficacy of bivalirudin as a possible substitute for UFH in anticoagulation during peripheral vascular bare-metal stent implantation

  9. Laser damage of HR, AR-coatings, monolayers and bare surfaces at 1064 nm

    Science.gov (United States)

    Garnov, S. V.; Klimentov, S. M.; Said, A. A.; Soileau, M. J.

    1993-01-01

    Laser induced damage thresholds and morphologies were investigated in a variety of uncoated and coated surfaces, including monolayers and multi-layers of different chemical compositions. Both antireflective (AR) and highly reflective (HR) were tested. Testing was done at 1064 nm with 25 picosecond and 8 nanosecond YAG/Nd laser single pulses. Spot diameter in the experiments varied from 0.09 to 0.22 mm. The laser damage measurement procedure consisted of 1-on-1 (single laser pulse in the selected site) and N-on-1 experiments including repeated irradiation by pulses of the same fluence and subsequently raised from pulse to pulse fluence until damage occurred. The highest picosecond damage thresholds of commercially available coatings averaged 12 - 14 J/sq cm, 50 percent less than thresholds obtained in bare fused silica. Some coatings and bare surfaces revealed a palpable preconditioning effect (an increase in threshold of 1.2 to 1.8 times). Picosecond and nanosecond data were compared to draw conclusions about pulse width dependence. An attempt was made to classify damage morphologies according to the type of coating, class of irradiating, and damage level.

  10. Research reactors - an overview

    Energy Technology Data Exchange (ETDEWEB)

    West, C.D.

    1997-03-01

    A broad overview of different types of research and type reactors is provided in this paper. Reactor designs and operating conditions are briefly described for four reactors. The reactor types described include swimming pool reactors, the High Flux Isotope Reactor, the Mark I TRIGA reactor, and the Advanced Neutron Source reactor. Emphasis in the descriptions is placed on safety-related features of the reactors. 7 refs., 7 figs., 2 tabs.

  11. IRPhE-TAPIRO-ARCHIVE, Fast neutron source reactor primary documents, reactor physics experiments

    International Nuclear Information System (INIS)

    Description of program or function: The TAPIRO reactor, located in the ENEA Casaccia Centre near Rome, is a highly enriched uranium fast neutron facility. The nominal power is 5 kW (thermal) and the core centre neutron flux is 4. E12/cm2/s. The reactor has a cylindrical core (12.6 cm diameter and 10.9 cm height) made of 93.5 % enriched uranium metal in a uranium-molybdenum alloy which is totally reflected by copper. The copper reflector (cylindrical-shaped) is divided into two concentric zones: the inner zone, up to 17.4 cm radius, and the outer zone up to 40.0 cm. Radius. The height of the reflector is 72.0 cm. The reactor is surrounded by borate concrete shielding about 170 cm thick. The maximum depth available for the epithermal column is 160 cm, reserved for filter/moderator materials. The graphite column extends to the external reflector boundary where a sector of the outer copper reflector has been removed and then characterized by a very hard neutron spectrum. Along the column the spectrum gradually softens up to thermal values - Different materials can be interposed, such as U-nat, Pb, Fe, etc. to reproduce spectrum transition conditions at interface points between regions with different compositions. - Activation foils can be used for activation analysis with threshold energies in the fast, intermediate and epithermal regions. The archive contains reports characterising the reactor and describes experiments carried out, together with the corresponding data

  12. Neutron flux measurements in PUSPATI Triga Reactor

    International Nuclear Information System (INIS)

    Neutron flux measurement in the PUSPATI TRIGA Reactor (PTR) was initiated after its commissioning on 28 June 1982. Initial measured thermal neutron flux at the bottom of the rotary specimen rack (rotating) and in-core pneumatic terminus were 3.81E+11 n/cm2 sec and 1.10E+12n/cm2 sec respectively at 100KW. Work to complete the neutron flux data are still going on. The cadmium ratio, thermal and epithermal neutron flux are measured in the reactor core, rotary specimen rack, in-core pneumatic terminus and thermal column. Bare and Cadmium covered gold foils and wires are used for the above measurement. The activities of the irradiated gold foils and wires are determined using Ge(Li) and hyperpure germinium detectors. (author)

  13. Stochastic Integral with respect to Cylindrical Wiener Process

    OpenAIRE

    Karczewska, Anna

    2005-01-01

    This paper is devoted to a construction of the stochastic It\\^o integral with respect to infinite dimensional cylindrical Wiener process. The construction given is an alternative one to that introduced by DaPrato and Zabczyk [3]. The connection of the introduced integral with the integral defined by Walsh [9] is provided as well.

  14. Magnetoresistance of cylindrical nanowires with artificial pinning site

    KAUST Repository

    Vidal, Enrique Vilanova

    2015-05-01

    New concepts of magnetic memory devices are exploiting the movement of data bits by current induced domain wall motion. This concept has been widely explored with rectangular nanowires (NWs) or stripes both theoretically and experimentally [1]. In the case of cylindrical NWs not much progress has been made on the experimental side, despite its promising advantages like the absence of Walker breakdown [2].

  15. Cylindrical contact homology of subcritical Stein-fillable contact manifolds

    OpenAIRE

    Yau, Mei-Lin

    2004-01-01

    We use contact handle decompositions and a stabilization process to compute the cylindrical contact homology of a subcritical Stein-fillable contact manifold with vanishing first Chern class, and show that it is completely determined by the homology of a subcritical Stein-filling of the contact manifold.

  16. Cylindrical dielectric resonator for Josephson plasma resonance measurement

    International Nuclear Information System (INIS)

    The design of a cylindrical dielectric cavity operated in various TMnmp modes, suitable for Josephson plasma resonance measurements of small superconducting high-Tc single crystals, is described. Its resonant frequencies are calculated analytically using the perturbation theory and compared with experimental results. An outline of the measurement procedure is provided. Experimental results measured at several frequencies are presented

  17. Mathematical modeling of flutter of viscoelastic plates and cylindrical panels

    OpenAIRE

    B. A. Khudayarov

    2006-01-01

    The flutter of viscoelastic plates and cylindrical panels streamlined by a gas current are investigated. The basic direction of the present work consists in taking into account of viscoelastic material properties at supersonic speeds. An algorithm of the numerical solution for the problem has been worked out on the basic of the method. The results of the flutter critical speed calculations have been given.

  18. Charged Cylindrical Polytropes with Generalized Polytropic Equation of State

    CERN Document Server

    Azam, M; Noureen, I; Rehman, M A

    2016-01-01

    We study the general formalism of polytropes in relativistic regime with generalized polytropic equations of state in the vicinity of cylindrical symmetry. We take charged anisotropic fluid distribution of matter with conformally flat condition for the development of general framework of polytropes. We discussed the stability of the model by Whittaker formula and concluded that one of the developed model is physically viable.

  19. Dynamical constants of structured photons with parabolic-cylindrical symmetry

    International Nuclear Information System (INIS)

    Electromagnetic modes with parabolic-cylindrical symmetry and their dynamical variables are studied both in the classical and quantum realms. As a result, a dynamical constant for the electromagnetic field is identified and linked to the symmetry operator which supports it.

  20. Static Solutions of Einstein's Equations with Cylindrical Symmetry

    Science.gov (United States)

    Trendafilova, C. S.; Fulling, S. A.

    2011-01-01

    In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well-known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the spacetime is…

  1. Strength Reliability Analysis of Stiffened Cylindrical Shells Considering Failure Correlation

    Institute of Scientific and Technical Information of China (English)

    Xu Bai; Liping Sun; Wei Qin; Yongkun Lv

    2014-01-01

    The stiffened cylindrical shell is commonly used for the pressure hull of submersibles and the legs of offshore platforms. There are various failure modes because of uncertainty with the structural size and material properties, uncertainty of the calculation model and machining errors. Correlations among failure modes must be considered with the structural reliability of stiffened cylindrical shells. However, the traditional method cannot consider the correlations effectively. The aim of this study is to present a method of reliability analysis for stiffened cylindrical shells which considers the correlations among failure modes. Firstly, the joint failure probability calculation formula of two related failure modes is derived through use of the 2D joint probability density function. Secondly, the full probability formula of the tandem structural system is given with consideration to the correlations among failure modes. At last, the accuracy of the system reliability calculation is verified through use of the Monte Carlo simulation. Result of the analysis shows the failure probability of stiffened cylindrical shells can be gained through adding the failure probability of each mode.

  2. Hypersonic Magneto-Fluid-Dynamic Compression in Cylindrical Inlet

    Science.gov (United States)

    Shang, Joseph S.; Chang, Chau-Lyan

    2007-01-01

    Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a cylindrical inlet. In a side-by-side experimental and computational study, the magnitude of the induced compression was found to be depended on configuration and electrode placement. To better understand the interacting phenomenon the present investigation is focused on a direct current discharge at the leading edge of a cylindrical inlet for which validating experimental data is available. The present computational result is obtained by solving the magneto-fluid-dynamics equations at the low magnetic Reynolds number limit and using a nonequilibrium weakly ionized gas model based on the drift-diffusion theory. The numerical simulation provides a detailed description of the intriguing physics. After validation with experimental measurements, the computed results further quantify the effectiveness of a magnet-fluid-dynamic compression for a hypersonic cylindrical inlet. At a minuscule power input to a direct current surface discharge of 8.14 watts per square centimeter of electrode area produces an additional compression of 6.7 percent for a constant cross-section cylindrical inlet.

  3. The Volume of a Torus Using Cylindrical and Spherical Coordinates

    Science.gov (United States)

    Farmer, Jim

    2005-01-01

    The author of this article, while recently working through some problem sets on determining volumes by triple integrals in cylindrical and spherical coordinate systems, realized that, although the textbook he was using included many interesting problems involving spheres, cylinders and cones and the increasingly complex solids that arose from the…

  4. Design of steel vertical and cylindrical tanks on models

    Energy Technology Data Exchange (ETDEWEB)

    Shutov, V.Ye.; Dmitriyev, N.N.

    1983-01-01

    Main principles are presented for using the expanded afine similarity for modeling tanks and studying their stressed-deformed state. Recommendations are made for selecting the materials for making the models of steel vertical cylindrical tanks and determining their overall dimensions.

  5. Properties of the cylindrical rf cavity evaluation code SUPERFISH

    International Nuclear Information System (INIS)

    A new rf cavity code has been developed that allows evaluation of resonant frequencies and field distributions of the fundamental and higher order modes for practically all conceivable cylindrical geometries. A short description of the procedure to determine these quantities is followed by a discussion of the accuracy of the code, its capabilities, and some applications. (author)

  6. A cylindrical drift chamber with azimuthal and axial position readout

    International Nuclear Information System (INIS)

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in π-p interactions. We describe the chamber's design considerations, details of its construction, electronics, and performance characteristics. (orig.)

  7. EXPERIMENTAL RESEARCH ON RADIATION FROM DOUBLE CYLINDRICAL STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    JI Gang; ZHANG Wei-kang; ZHOU Qi-dou

    2006-01-01

    An experiment on radiation from double cylindrical structures was held in an open-air pond. Radiation responses from one-point harmonic force driven model and two-point stochastic forces driven model were measured. Numerical results show a good agreement with the experimental results. Possible errors are analyzed.

  8. Cylindrical Bending of a Plate on an Elastic Foundation

    Czech Academy of Sciences Publication Activity Database

    Gronát, Petr

    Ostrava : VŠB - Technical University of Ostrava, 2011, C376-C393. ISBN 978-80-248-2257-0 R&D Projects: GA ČR GAP101/10/1230 Institutional research plan: CEZ:AV0Z20760514 Keywords : elastic foundation * cylindrical bending Subject RIV: JI - Composite Materials

  9. Development of new cylindrical magnetrons for industrial use

    CERN Document Server

    Clayton, B

    2000-01-01

    four-fold system. In an attempt to tackle this problem, a finite element model of the magnetic field generated by the magnetic assembly was built, run and verified. Changes were made to this model, and a new .magnet assembly was built and tested based on the results obtained. This did not lead to a final solution of the problem, but has set bounds within which the solution must lie. A number of alternative techniques were considered and tested with a view to the construction of a cylindrical sputtering device. This device was required to be capable of depositing tribological coatings inside approximately cylindrical substrates of diameters less than 100mm, in an industrial situation. A cylindrical magnetron device was designed, and constructed as a prototype, using a magnetic assembly inside a cylindrical target with outside diameter (o.d.) 40mm. Two alternative magnetic assemblies were tested, and found to have complimentary advantages. The magnetron characteristics of the device were tested, as were key pro...

  10. A circumferential crack in a cylindrical shell under tension.

    Science.gov (United States)

    Duncan-Fama, M. E.; Sanders, J. L., Jr.

    1972-01-01

    A closed cylindrical shell under uniform internal pressure has a slit around a portion of its circumference. Linear shallow shell theory predicts inverse square-root-type singularities in certain of the stresses at the crack tips. This paper reports the computed strength of these singularities for different values of a dimensionless parameter based on crack length, shell radius and shell thickness.

  11. Efficient Generation of Truncated Bessel Beams using Cylindrical Waveguides

    Science.gov (United States)

    Ilchenko, Vladimir S.; Mohageg, Makan; Savchenkov, Anatoliy A.; Matsko, Andrey B.; Maleki, Lute

    2007-01-01

    In this paper we address efficient conversion between a Gaussian beam (a truncated plane wave) and a truncated Bessel beam of agiven order, using cylindrical optical waveguides and whispering gallery mode resonators. Utilizing a generator based on waveguides combined with whispering gallery mode resonators, we have realized Bessel beams of the order of 200 with a conversion efficiency exceeding 10 %.

  12. Linear stationary states of dissipative modes in cylindrical geometry

    International Nuclear Information System (INIS)

    The theory of resistive instabilities (tearing and interchange) has been reworked including the full collisional viscous tensor and thermal conductivity in cylindrical geometry. Particular attention is devoted to the existence of stationary states made possible by the presence of viscous effects. These states are important as they form the basis for calculating anomalous heat transport in weakly nonlinear regimes

  13. Reactor vessel for pebble beds

    International Nuclear Information System (INIS)

    The wall and the bottom of the vessel for the gas-cooled pebble-bed reactor consist of numerous blocks of graphite or carbon rock piled up. They are held together by an exterior cylindrical or polygonal ring and supported by a foundation. The blocks form coherent sectors resp. annular sectors with well-defined separating lines. At high temperatures or load change operation these sectors behave like monolithic blocks expanding heely and contracting again, the center of the vessel remaining fixed. The forces causing the compression result from the own weight of the sectors and the weight of the pebble bed. This motion is supported by the convex arrangement of the opposite surfaces of the sectors and the supporting walls and by roller bearings. The bottom of the vessel may be designed funnel-shaped, in this way facilitating the removal of spheres. (DG)

  14. Cavity seal for reactor container and manufacturing method therefor

    International Nuclear Information System (INIS)

    A reactor container of a LWR type reactor is suspended in a reactor cavity formed in a concrete structure in the reactor container. An upper ring portion of the cavity seals is welded to an upper flange of a main body of the reactor container. In addition, a lower disk portion of the cavity seal connected to the upper ring portion by way of a cylinder portion is welded to a liner plate disposed on the surface of the concrete structure in the reactor container. A curved cross sectional portion having a moderately curved portion is formed at the lower portion of the cylindrical portion of the cavity seal, and the lower disk portion is welded thereto. Since the carved cross sectional portion is formed to the cylindrical portion of the cavity seal, deformation due to the difference of thermal expansion is caused not being concentrated but dispersed. Accordingly, thermal stresses to be caused are reduced thereby enabling to prevent thermal fatigue destruction. (I.N.)

  15. Reactor utilization

    International Nuclear Information System (INIS)

    In 1962, the RA reactor was operated almost three times more than in 1961, producing total of 25 555 MWh. Diagram containing comparative data about reactor operation for 1960, 1961, and 1962, percent of fuel used and U-235 burnup shows increase in reactor operation. Number of samples irradiated was 659, number of experiments done was 16. mean powered level was 5.93 MW. Fuel was added into the core twice during the reporting year. In fact the core was increased from 56 to 68 fuel channels and later to 84 fuel channels. Fuel was added to the core when the reactivity worth decreased to the minimum operation level due to burnup. In addition to this 5 central fuel channels were exchanged with fresh fuel in february for the purpose of irradiation in the VISA-2 channel

  16. Reactor Neutrinos

    CERN Document Server

    Lasserre, T; Lasserre, Thierry; Sobel, Henry W.

    2005-01-01

    We review the status and the results of reactor neutrino experiments, that toe the cutting edge of neutrino research. Short baseline experiments have provided the measurement of the reactor neutrino spectrum, and are still searching for important phenomena such as the neutrino magnetic moment. They could open the door to the measurement of coherent neutrino scattering in a near future. Middle and long baseline oscillation experiments at Chooz and KamLAND have played a relevant role in neutrino oscillation physics in the last years. It is now widely accepted that a new middle baseline disappearance reactor neutrino experiment with multiple detectors could provide a clean measurement of the last undetermined neutrino mixing angle theta13. We conclude by opening on possible use of neutrinos for Society: NonProliferation of Nuclear materials and Geophysics.

  17. Nuclear reactors

    International Nuclear Information System (INIS)

    A nuclear reactor has a large prompt negative temperature coefficient of reactivity. A reactor core assembly of a plurality of fluid-tight fuel elements is located within a water-filled tank. Each fuel element contains a solid homogeneous mixture of 50-79 w/o zirconium hydride, 20-50 w/o uranium and 0.5-1.5 W erbium. The uranium is not more than 20 percent enriched, and the ratio of hydrogen atoms to zirconium atoms is between 1.5:1 and 7:1. The core has a long lifetime, E.G., at least about 1200 days

  18. Nuclear reactors

    International Nuclear Information System (INIS)

    In a liquid cooled nuclear reactor, the combination is described for a single-walled vessel containing liquid coolant in which the reactor core is submerged, and a containment structure, primarily of material for shielding against radioactivity, surrounding at least the liquid-containing part of the vessel with clearance therebetween and having that surface thereof which faces the vessel make compatible with the liquid, thereby providing a leak jacket for the vessel. The structure is preferably a metal-lined concrete vault, and cooling means are provided for protecting the concrete against reaching a temperature at which damage would occur. (U.S.)

  19. Construction for holding together a cylindrical high pressure reactor vessel with hemispherical bottom and lid

    International Nuclear Information System (INIS)

    The construction shall prevent that in case of ruptures of the vessel rupture pieces may damage the secondary shielding system. The construction consists of two yokes fitting to the bottom and the lid of the vessel and held together by means of pull rods. The yokes are designed as truncated conshaped shells. The smaller end of the cone shells supports the hemispherical bottom and the lid of the vessel. The larger cone shell ends are tied together by the pull rods. As further improvements there may be arranged hemispherical protective shields between the hemispherical bottom and the lid of the vessel and the smaller end of the cone shells. (P.K.)

  20. Soft landing of bare PtRu nanoparticles for electrochemical reduction of oxygen

    Science.gov (United States)

    Johnson, Grant E.; Colby, Robert; Engelhard, Mark; Moon, Daewon; Laskin, Julia

    2015-07-01

    Magnetron sputtering of two independent Pt and Ru targets coupled with inert gas aggregation in a modified commercial source has been combined with soft landing of mass-selected ions to prepare bare 4.5 nm diameter PtRu nanoparticles on glassy carbon electrodes with controlled size and morphology for electrochemical reduction of oxygen in solution. Employing atomic force microscopy (AFM) it is shown that the nanoparticles bind randomly to the glassy carbon electrode at a relatively low coverage of 7 × 104 ions μm-2 and that their average height is centered at 4.5 nm. Scanning transmission electron microscopy images obtained in the high-angle annular dark field mode (HAADF-STEM) further confirm that the soft-landed PtRu nanoparticles are uniform in size. Wide-area scans of the electrodes using X-ray photoelectron spectroscopy (XPS) reveal the presence of both Pt and Ru in atomic concentrations of ~9% and ~33%, respectively. Deconvolution of the high energy resolution XPS spectra in the Pt 4f and Ru 3d regions indicates the presence of both oxidized Pt and Ru. The substantially higher loading of Ru compared to Pt and enrichment of Pt at the surface of the nanoparticles is confirmed by wide-area analysis of the electrodes using time-of-flight medium energy ion scattering (TOF-MEIS) employing both 80 keV He+ and O+ ions. The activity of electrodes containing 7 × 104 ions μm-2 of bare 4.5 nm PtRu nanoparticles toward the electrochemical reduction of oxygen was evaluated employing cyclic voltammetry (CV) in 0.1 M HClO4 and 0.5 M H2SO4 solutions. In both electrolytes a pronounced reduction peak was observed during O2 purging of the solution that was not evident during purging with Ar. Repeated electrochemical cycling of the electrodes revealed little evolution in the shape or position of the voltammograms indicating high stability of the nanoparticles supported on glassy carbon. The reproducibility of the nanoparticle synthesis and deposition was evaluated by

  1. Soft Landing of Bare PtRu Nanoparticles for Electrochemical Reduction of Oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Colby, Robert J.; Engelhard, Mark H.; Moon, DaeWon; Laskin, Julia

    2015-08-07

    Magnetron sputtering of two independent Pt and Ru targets coupled with inert gas aggregation in a modified commercial source has been combined with soft landing of mass-selected ions to prepare bare 4.5 nm diameter PtRu alloy nanoparticles on glassy carbon electrodes with controlled size and morphology for electrochemical reduction of oxygen in solution. Employing atomic force microscopy (AFM) it is shown that the nanoparticles bind randomly to the glassy carbon electrode at a relatively low coverage of 7 x 104 ions µm-2 and that their average height is centered at 4 nm. Scanning transmission electron microscopy images obtained in the high-angle annular dark field mode (STEM-HAADF) further confirm that the soft-landed PtRu alloy nanoparticles are uniform in size and have a Ru core decorated with small regions of Pt on the surface. Wide-area scans of the electrodes using X-ray photoelectron spectroscopy (XPS) reveal the presence of both Pt and Ru in relative atomic concentrations of ~9% and ~33%, respectively. Deconvolution of the high energy resolution XPS spectra in the Pt4f and Ru3d regions indicates the presence of both oxidized Pt and Ru. The substantially higher loading of Ru compared to Pt and enrichment of Pt at the surface of the alloy nanoparticles is confirmed by wide-area analysis of the electrodes using time-of-flight medium energy ion scattering (TOF-MEIS) employing both 80 keV He+ and O+ ions. The activity of electrodes containing 7 x 104 ions µm-2 of bare 4.5 nm PtRu nanoparticles toward the electrochemical reduction of oxygen was evaluated employing cyclic voltammetry (CV) in 0.1 M HClO4 and 0.5 M H2SO4 solutions. In both electrolytes a pronounced reduction peak was observed during O2 purging of the solution that was not evident during purging with Ar. Repeated electrochemical cycling of the electrodes revealed little evolution in the shape or position of the voltammograms indicating high stability of the alloy nanoparticles supported on glassy

  2. Pebble Bed Reactor Plant screening evaluation. Volume 1. Overall plant and reactor system

    International Nuclear Information System (INIS)

    This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW/sub t/ Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. Volume 1 reports the overall plant and reactor system. Core scoping studies were performed which evaluated the effects of annular and cyclindrical core configurations, radial blanket zones, burnup, and ball heavy metal loadings. The reactor system, including the PCRV, was investigated for both the annular and cylindrical core configurations

  3. SHETAN - a three dimensional transport code for reactor analysis

    International Nuclear Information System (INIS)

    SHETAN, a three-dimensional neutron transport code, is based on the block method of solving the integral transport equation, which combines the advantages of the conventional collision probability method and the interface current technique and has made possible a large increase in the size of problem that can be handled. The code mixed rectangular and cylindrical coordinates, allowing cylindrical fuel channels and reactivity devices to be modelled within a rectangular cell. Details of the calculational method for the collision probabilities in these mixed coordinates are described. Applications of SHETAN to analyze booster and adjuster experiments done in the ZED-2 reactor are also described. Satisfactory agreement with measurements confirm that SHETAN is a useful tool for reactor analyses where three-dimensional calculations are required. (auth)

  4. Nuclear reactor

    International Nuclear Information System (INIS)

    In an improved reactor core for a high conversion BWR reactor, Pu-breeding type BWR type reactor, Pu-breeding type BWR type rector, FEBR type reactor, etc., two types of fuel assemblies are loaded such that fuel assemblies using a channel box of a smaller irradiation deformation ratio are loaded in a high conversion region, while other fuel assemblies are loaded in a burner region. This enables to suppress the irradiation deformation within an allowable limit in the high conversion region where the fast neutron flux is high and the load weight from the inside of the channel box due to the pressure loss is large. At the same time, the irradiation deformation can be restricted within an allowable limit without deteriorating the neutron economy in the burner region in which fast neutron flux is low and the load weight from the inside of the channel box is small since a channel box with smaller neutron absorption cross section or reduced wall thickness is charged. As a result, it is possible to prevent structural deformations such as swelling of the channel box, bending of the entire assemblies, bending of fuel rods, etc. (K.M.)

  5. Size-controllable synthesis of bare gold nanoparticles by femtosecond laser fragmentation in water

    International Nuclear Information System (INIS)

    We report a size-controllable synthesis of stable aqueous solutions of ultrapure low-size-dispersed Au nanoparticles by methods of femtosecond laser fragmentation from preliminary formed colloids. Such approach makes possible the tuning of mean nanoparticle size between a few nm and several tens of nm under the size dispersion lower than 70% by varying the fluence of pumping radiation during the fragmentation procedure. The efficient size control is explained by 3D geometry of laser fragmentation by femtosecond laser-induced white light super-continuum and plasma-related phenomena. Despite the absence of any protective ligands, the nanoparticle solutions demonstrate exceptional stability due to electric repulsion effect associated with strong negative charging of formed nanoparticles. Stable aqueous solutions of bare gold nanoparticles present a unique object with a variety of potential applications in catalysis, surface-enhanced Raman spectroscopy, photovoltaics, biosensing and biomedicine. (paper)

  6. Morphology and Optical Properties of Bare and Silica Coated Hybrid Silver Nanoparticles.

    Science.gov (United States)

    Ghimire, Sushant; Lebek, Werner; Godehardt, Reinhold; Lee, Wan In; Adhikari, Rameshwar

    2016-05-01

    Owing to their wide applications in the field of optoelectronics, photonics, catalysis, and medicine; plasmonic metal nanoparticles are attaining considerable interest nowadays. The optical properties of these metal nanoparticles depend upon their size, shape, and surrounding medium. The present work studies the morphology and optical properties of bare silver nanoparticles and silica coated hybrid silver nanoparticles. Aqueous phase mediated synthesis and water-in-oil microemulsion mediated synthesis are two different wet chemical routes employed for nanosynthesis. Direct coating of silica is performed in water-in-oil microemulsion on pre-synthesized silver nanoparticles using tetraethyl orthosilicate as silica precursor. This study shows that using different wet chemical routes the size of the synthesized nanoparticles could be tuned. In addition, using reverse micelles as nanoreactors, the thickness of the silica shell around the core silver nanoparticles could be significantly controlled. Further, the optical properties of silver nanoparticles could be adjusted through the size and the surface coating. PMID:27483900

  7. Distorted wave calculations for electron loss process induced by bare ion impact on biological targets

    International Nuclear Information System (INIS)

    Distorted wave models are employed to investigate the electron loss process induced by bare ions on biological targets. The two main reactions which contribute to this process, namely, the single electron ionization as well as the single electron capture are here studied. In order to further assess the validity of the theoretical descriptions used, the influence of particular mechanisms are studied, like dynamic screening for the case of electron ionization and energy deposition on the target by the impacting projectile for the electron capture one. Results are compared with existing experimental data. - Highlights: ► Distorted wave models are used to investigate ion-molecule collisions. ► Differential and total cross-sections for capture and ionization are evaluated. ► The influence of dynamic screening is determined. ► Capture reaction dominates the mean energy deposited by the projectile on the target

  8. Strongly confining bare core CdTe quantum dots in polymeric microdisk resonators

    Directory of Open Access Journals (Sweden)

    Assegid Flatae

    2014-01-01

    Full Text Available We report on a simple route to the efficient coupling of optical emission from strongly confining bare core CdTe quantum dots (QDs to the eigenmodes of a micro-resonator. The quantum emitters are embedded into QD/polymer sandwich microdisk cavities. This prevents photo-oxidation and yields the high dot concentration necessary to overcome Auger enhanced surface trapping of carriers. In combination with the very high cavity Q-factors, interaction of the QDs with the cavity modes in the weak coupling regime is readily observed. Under nanosecond pulsed excitation the CdTe QDs in the microdisks show lasing with a threshold energy as low as 0.33 μJ.

  9. Self-Assembly of Graphene Nanoblisters Sealed to a Bare Metal Surface.

    Science.gov (United States)

    Larciprete, Rosanna; Colonna, Stefano; Ronci, Fabio; Flammini, Roberto; Lacovig, Paolo; Apostol, Nicoleta; Politano, Antonio; Feulner, Peter; Menzel, Dietrich; Lizzit, Silvano

    2016-03-01

    The possibility to intercalate noble gas atoms below epitaxial graphene monolayers coupled with the instability at high temperature of graphene on the surface of certain metals has been exploited to produce Ar-filled graphene nanosized blisters evenly distributed on the bare Ni(111) surface. We have followed in real time the self-assembling of the nanoblisters during the thermal annealing of the Gr/Ni(111) interface loaded with Ar and characterized their morphology and structure at the atomic scale. The nanoblisters contain Ar aggregates compressed at high pressure arranged below the graphene monolayer skin that is decoupled from the Ni substrate and sealed only at the periphery through stable C-Ni bonds. Their in-plane truncated triangular shapes are driven by the crystallographic directions of the Ni surface. The nonuniform strain revealed along the blister profile is explained by the inhomogeneous expansion of the flexible graphene lattice that adjusts to envelop the Ar atom stacks. PMID:26829243

  10. The Integrity bare-metal stent made by continuous sinusoid technology.

    Science.gov (United States)

    Turco, Mark A

    2011-05-01

    The Integrity Coronary Stent System (Medtronic Vascular, CA, USA) is a low-profile, open-cell, cobalt-chromium-alloy advanced bare-metal iteration of the well-known Driver/Micro-Driver Coronary Stent System (Medtronic Vascular). The Integrity stent is made with a process called continuous sinusoid technology. This process allows stent construction via wrapping a single thin strand of wire around a mandrel in a sinusoid configuration, with laser fusion of adjacent crowns. The wire-forming process and fusion pattern provide the stent with a continuous preferential bending plane, intended to allow easier access to, and smoother tracking within, distal and tortuous vessels while radial strength is maintained. Continuous sinusoid technology represents innovation in the design of stent platforms and will provide a future stent platform for newer technology, including drug-eluting stent platforms, drug-filled stents and core wire stents. PMID:21542702

  11. Velocity-space pictures of continuum electrons produced by slow, bare, highly charged ions

    International Nuclear Information System (INIS)

    Velocity-space pictures of the electron continua produced by the impact of ions on He and Ne have been measured for the bare projectiles of p, He, C, O, and Ne at a projectile velocity of 1.63 a.u. For the three highly charged projectiles, this velocity lies in the ionization open-quotes thresholdclose quotes region where electron capture dominates the reaction. The electron velocity-space distributions for these cases are concentrated near the velocity of the projectile, not near the saddle-point velocity, and seem to open-quotes saturateclose quotes at a nearly universal shape. The data are in qualitative agreement with CDW-EIS calculations. copyright 1997 The American Physical Society

  12. Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements

    DEFF Research Database (Denmark)

    Jensen, Kaj Sand; Hammer, Kathrine

    2012-01-01

    Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species...... under stagnant conditions. One moss species was added to the species pool for every nine-fold increase in cushion area. Vascular plants were absent from the smallest cushions, whereas one or two species, on average, appeared in 375- and 8,500-cm(2) cushions with water available for 6 and 10 days during...... desiccation. Phosphorus concentrations increased stepwise and four-fold from detritus to surface mosses and to vascular plants, and all three pools increased with cushion size. We conclude that cushion mosses and cushion size play a critical role in this resource-limited limestone environment by offering an...

  13. Paradoxical switching to a barely-mastered second language by an aphasic patient.

    Science.gov (United States)

    Leemann, B; Laganaro, M; Schwitter, V; Schnider, A

    2007-06-01

    Polyglot speakers who become aphasics are not necessarily affected to the same extent in each language. In some cases there is a mixing of the different languages or a switching between languages and in very rare cases the switch is to the language seldom if ever used in everyday live. We report a French-speaking aphasic, who switched paradoxically from his mother tongue (French) to a second language (German) which he had learned at school but barely mastered and hardly ever spoke, and kept using German most of the time. We tried to understand the mechanism responsible for that phenomenon by reviewing the actual hypothesis of multi-language organization. We concluded, in line with previous reports, that our case used his metalinguistic knowledge to compensate for his inability to access his linguistic skills. PMID:17786781

  14. Remote sensing of soil moisture content over bare field at 1.4 GHz frequency

    Science.gov (United States)

    Wang, J. R.; Choudhury, B. J.

    1981-01-01

    An algorithm for estimating moisture content of a bare soil from the observed brightness temperature at 1.4 GHz is discussed and applied to a limited data base. The method is based on a radiative transfer model calculation, which has been successfully used in the past to account for many observational results, with some modifications to take into account the effect of surface roughness. Besides the measured brightness temperatures, the three additional inputs required by the method are the effective soil thermodynamic temperature, the precise relation between moisture content and the smooth field brightness temperatures and a pair of parameters related to surface roughness. The procedures of estimating surface roughness parameters and of obtaining moisture content from observed brightness temperature are discussed. The algorithm is applied to observations from truck mounted and airborne radiometers. The estimated moisture contents compare favorably with the observations in the top 2 cm layer.

  15. Soil microbial activities beneath Stipa tenacissima L. and in surrounding bare soil

    Science.gov (United States)

    Novosadová, I.; Ruiz Sinoga, J. D.; Záhora, J.; Fišerová, H.

    2010-05-01

    Open steppes dominated by Stipa tenacissima L. constitute one of the most representative ecosystems of the semi-arid zones of Eastern Mediterranean Basin (Iberian Peninsula, North of Africa). These steppes show a higher degree of variability in composition and structure. Ecosystem functioning is strongly related to the spatial pattern of grass tussocks. Soils beneath S. tenacissima grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands" (Maestre et al., 2007). On the other hand in "resource islands" and in surrounding bare soil exists the belowground zone of influence. The competition for water and resources between plants and microorganisms is strong and mediated trough an enormous variety of exudates and resource depletion intended to regulate soil microbial communities in the rhizosphere, control herbivory, encourage beneficial symbioses, and change chemical and physical properties in soil (Pugnaire et Armas, 2008). Secondary compounds and allelopathy restrict other species growth and contribute to patchy plant distribution. Active root segregation affects not only neighbourś growth but also soil microbial activities. The objective of this study was to assess the effect of Stipa tenacissima on the key soil microbial activities under controlled incubation conditions (basal and potential respiration; net nitrogen mineralization). The experimental plots were located in the province Almería in Sierra de los Filabres Mountains near the village Gérgal (southeast Spain) in the small catchment which is situated between 1090 - 1165 m a.s.l. The area with extent of 82 000 m2 is affected by soil degradation. The climate is semiarid Mediterranean. The mean annual rainfall is of about 240 mm mostly concentrated in autumn and spring. The mean annual temperature is 13.9° C. The studied soil has a loam to sandy clay texture and is classified as Lithosol (FAO-ISRIC and ISSS, 1998). The vegetation of these areas is an

  16. Reliability Optimization of Radial Distribution Systems Employing Differential Evolution and Bare Bones Particle Swarm Optimization

    Science.gov (United States)

    Kela, K. B.; Arya, L. D.

    2014-09-01

    This paper describes a methodology for determination of optimum failure rate and repair time for each section of a radial distribution system. An objective function in terms of reliability indices and their target values is selected. These indices depend mainly on failure rate and repair time of a section present in a distribution network. A cost is associated with the modification of failure rate and repair time. Hence the objective function is optimized subject to failure rate and repair time of each section of the distribution network considering the total budget allocated to achieve the task. The problem has been solved using differential evolution and bare bones particle swarm optimization. The algorithm has been implemented on a sample radial distribution system.

  17. Atomistic electrodynamics simulations of bare and ligand-coated nanoparticles in the quantum size regime.

    Science.gov (United States)

    Chen, Xing; Moore, Justin E; Zekarias, Meserret; Jensen, Lasse

    2015-01-01

    The optical properties of metallic nanoparticles with nanometre dimensions exhibit features that cannot be described by classical electrodynamics. In this quantum size regime, the near-field properties are significantly modified and depend strongly on the geometric arrangements. However, simulating realistically sized systems while retaining the atomistic description remains computationally intractable for fully quantum mechanical approaches. Here we introduce an atomistic electrodynamics model where the traditional description of nanoparticles in terms of a macroscopic homogenous dielectric constant is replaced by an atomic representation with dielectric properties that depend on the local chemical environment. This model provides a unified description of bare and ligand-coated nanoparticles, as well as strongly interacting nanoparticle dimer systems. The non-local screening owing to an inhomogeneous ligand layer is shown to drastically modify the near-field properties. This will be important to consider in optimization of plasmonic nanostructures for near-field spectroscopy and sensing applications. PMID:26555179

  18. Fast pyrolysis of Miscanthus sinensis in fluidized bed reactors: Characteristics of product yields and biocrude oil quality

    International Nuclear Information System (INIS)

    In the present work, fast pyrolysis of Miscanthus sinensis was performed and the product yields and properties of the resulting biocrude oil were determined for varying reactor configurations and pyrolysis temperatures. Two types of reactors (rectangular and cylindrical fluidized beds) were adopted, and pyrolysis temperature was increased from 400 °C to 550 °C. Based on the results, it was found that the reaction temperature greatly influenced the product yield and the characteristics of biocrude oil. The highest yield of biocrude oil for the rectangular reactor was 48.9 wt.%, produced at 500 °C, and the highest yield for the cylindrical reactor was 50.01 wt.%, produced at 450 °C. Additionally, the biocrude oil yield in the rectangular reactor sharply decreased when reaction temperature was increased to 550 °C, while only a slight decrease was observed in the cylindrical reactor. From GC/MS analysis, biocrude oil was found to contain various chemical components, such as nonaromatic ketones, furans, sugars, lignin-derived phenols, guaiacols and syringols. In particular, the sugar content of the biocrude oil produced in rectangular reactor (2.11–9.35 wt.%) was generally lower than that produced in the cylindrical reactor (7.93–10.79 wt.%). - Highlights: • Fast pyrolysis of Miscanthus sinensis was performed in two fluidized bed reactors to obtain biocrude oil. • The yield and characteristics of the biocrude oil were scrutinized with changing reaction temperature and reactor type. • The reaction temperature was found to be the most influencing parameter for the fast pyrolysis reaction. • The different heating rate caused by reactor type has an effect on the final product yield and characteristics

  19. The TAPIRO fast-neutron source reactor as a support to nuclear data assessment

    International Nuclear Information System (INIS)

    TAPIRO is a fast neutron source reactor operating at CASACCIA Research Center since 1971. The project, entirely developed by ENEA's staff, is based on the general concept of AFSR (Argonne Fast Source Reactor - Idaho Falls). The reactor is equipped with a homogeneous cylindrical core having 6.29 cm as radius and 10.87 cm as height; cladding is provided by stainless steel (0.5 mm thickness) placed on a cylindrical copper reflector having (30 cm as thickness). All components assembled in a stainless steel tank, are placed inside a near spherical borated concrete shielding system having 1.75 m as thickness. Channels of various dimension and with different neutron spectra are distributed around the core. A large thermal column is manufactured by graphite blocks, suitable to be removed and replaced with experimental assemblies for any research purpose. The TAPIRO possibilities for reactor experiments with energies up to 1.35 MeV will be illustrated. (author)

  20. Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

    Directory of Open Access Journals (Sweden)

    Rose Mary Ferreira Lisboa da Silva

    2014-08-01

    Full Text Available Background: The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. Objective: To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. Methods: This study assessed 61 patients (mean age, 64.0 years; 35 men with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform, measuring the low-frequency (LF and high-frequency (HF components, and the LF/HF ratio before and during the procedure. Results: Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively, with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00. The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Conclusions: Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents.