Isolation of radioactive thallium from lead targets

International Nuclear Information System (INIS)

Kozlova, M.D.; Sevast'yanova, A.S.; Malinin, A.B.; Kurenkov, N.V.

1989-01-01

Two methods of thallium-201 preperation from Pb-targets irradiated with protons: precipitation-extraction (1) and extraction (2) - are developed. When the target irraiated is extracted during the time necessary for bismuth-201 transformation into lead-201, lead macroquantity containing lead-201 was separated from undesirable thallium radionuclides, which are formed in direct nuclear reactions. The lead fraction was extracted to accumulate thallium-201, and it was separated from lead mocroquantity. The target was dissolved in the nitric acid. The 1st method differs from the 2nd one by the fact that before thallium-201 extraction, lead was precipitaed by the nitric acid. The 1st method permits to separate thallium-201 with chemical yield not less than 90 %, the 2nd one - ≥95 %. 2 refs

Filling of charged cylindrical capillaries

NARCIS (Netherlands)

Das, Siddhartha; Chanda, Sourayon; Eijkel, J.C.T.; Tas, N.R.; Chakraborty, Suman; Mitra, Sushanta K.

2014-01-01

We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because

Control of surface quality of sub-millimeter cylindrical gold targets

International Nuclear Information System (INIS)

Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zheng Wei; Zhang Lin; Sun Jingyuan; Chen Jing

2010-01-01

The morphology, composition and causes of defects are analyzed to reduce defects on the gold layer prepared by electrochemical deposition from sulfite solution, and to improve the surface quality of sub-millimeter cylindrical gold targets, by means of SEM and EDS. The effects of current density, metallic impurity, organic pollution, pre-deposition parameters and mandrel quality on the quality of the gold plating are discussed, along with their mechanisms. The result indicates that the current density must be controlled strictly. The optimal current density ranges from 2.4 to 3.2 mA/cm 2 when the concentration of gold ranges from 13 to 22 g/L, and from 2.0 to 2.6 mA/ cm 2 when the concentration of gold ranges from 5 to 13 g/L. The parameters of predeposition must be optimized and the predeposition time should be no longer than 1 minute to improve the surface quality. In addition, organic pollution should be removed from the bath, and the mandrels should be of good quality without oxide on their surfaces. (authors)

Target design for the cylindrical compression of matter driven by heavy ion beams

Energy Technology Data Exchange (ETDEWEB)

Piriz, A.R. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)]. E-mail: roberto.piriz@uclm.es; Temporal, M. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Lopez Cela, J.J. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Grandjouan, N. [LULI, UMR 7605, Ecole Polytechnique-CNRS-CEA-Universite Paris VI, Palaiseau (France); Tahir, N.A. [GSI Darmstadt, Plankstrasse 1, 64291 Darmstadt (Germany); Serna Moreno, M.C. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Portugues, R.F. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Hoffmann, D.H.H. [GSI Darmstadt, Plankstrasse 1, 64291 Darmstadt (Germany)

2005-05-21

The compression of a cylindrical sample of hydrogen contained in a hollow shell of Pb or Au has been analyzed in the framework of the experiments to be performed in the heavy ion synchrotron SIS100 to be constructed at the Gesellschaft fuer Schwerionenforschung (GSI) Darmstadt. The target implosion is driven by an intense beam of heavy ions with a ring-shaped focal spot. We report the results of a parametric study of the final state of the compressed hydrogen in terms of the target and beam parameters. We consider the generation of the annular heated region by means of a radio-frequency wobbler that rotates the beam at extremely high frequencies in order to accommodate symmetry constraints. We have also studied the hydrogen conditions that can be achieved with a non-rotating beam with Gaussian focal spot and the possibility to use a beam stopper as an alternative way to avoid the direct heating of the sample. Finally, we report the analysis of the hydrodynamic instabilities that affect the implosion and the mitigating effects of the elastoplastic properties of the shell.

Target design for the cylindrical compression of matter driven by heavy ion beams

International Nuclear Information System (INIS)

Piriz, A.R.; Temporal, M.; Lopez Cela, J.J.; Grandjouan, N.; Tahir, N.A.; Serna Moreno, M.C.; Portugues, R.F.; Hoffmann, D.H.H.

2005-01-01

The compression of a cylindrical sample of hydrogen contained in a hollow shell of Pb or Au has been analyzed in the framework of the experiments to be performed in the heavy ion synchrotron SIS100 to be constructed at the Gesellschaft fuer Schwerionenforschung (GSI) Darmstadt. The target implosion is driven by an intense beam of heavy ions with a ring-shaped focal spot. We report the results of a parametric study of the final state of the compressed hydrogen in terms of the target and beam parameters. We consider the generation of the annular heated region by means of a radio-frequency wobbler that rotates the beam at extremely high frequencies in order to accommodate symmetry constraints. We have also studied the hydrogen conditions that can be achieved with a non-rotating beam with Gaussian focal spot and the possibility to use a beam stopper as an alternative way to avoid the direct heating of the sample. Finally, we report the analysis of the hydrodynamic instabilities that affect the implosion and the mitigating effects of the elastoplastic properties of the shell

Radiation assisted thermonuclear burn wave dynamics in heavy ion fast ignition of cylindrical deuterium-tritium fuel target

International Nuclear Information System (INIS)

Rehman, S.; Kouser, R.; Nazir, R.; Manzoor, Z.; Tasneem, G.; Jehan, N.; Nasim, M.H.; Salahuddin, M.

2015-01-01

Dynamics of thermonuclear burn wave propagation assisted by thermal radiation precursor in a heavy ion fast ignition of cylindrical deuterium-tritium (DT) fuel target are studied by two dimensional radiation hydrodynamic simulations using Multi-2D code. Thermal radiations, as they propagate ahead of the burn wave, suffer multiple reflections and preheat the fuel, are found to play a vital role in burn wave dynamics. After fuel ignition, the burn wave propagates in a steady state manner for some time. Multiple reflection and absorption of radiation at the fuel-tamper interface, fuel ablation and radial implosion driven by ablative shock and fast fusion rates on the fuel axis, at relatively later times, result into filamentary wave front. Strong pressure gradients are developed and sausage like structures behind the front are appeared. The situation leads to relatively reduced and non-uniform radial fuel burning and burn wave propagation. The fuel burning due to DD reaction is also taken into account and overall fusion energy and fusion power density, due to DT and DD reactions, during the burn wave propagation are determined as a function of time. (authors)

In situ production of microporous foams in sub-millimeter cylindrical gold targets

International Nuclear Information System (INIS)

Fan Yongheng; Luo Xuan; Fang Yu; Ren Hongbo; Yuan Guanghui; Wang Honglian; Zhou Lan; Zhang Lin; Du Kai

2009-01-01

The preparation of microcellular foam in sub-millimeter cylindrical gold targets is described. Small, open-ended, gold cylinders of 400 μm diameter, 700 μm length, and 20 μm wall thickness were fabricated by electroplating gold onto a silicon bronze mandrel and leaching the mandrel with concentrated nitric acid. After several rinsing and cleaning steps, the cylinders were filled with a solution containing acrylate monomers. The solution was polymerized in situ with ultraviolet light to produce a gel. Precipitation of these gels in a non-solvent such as methanol and subsequent drying by means of a critical point drying apparatus produced cylinders filled with microporous foams. The foams have densities of 50 mg · cm -3 and cell sizes on more than 1 μm. They fill the cylinders completely without shrinkage during the drying process, and need no subsequent machining. (authors)

Verification of Compton scattering spectrum of a 662 keV photon beam scattered on a cylindrical steel target using MCNP5 code

International Nuclear Information System (INIS)

Thanh, Tran Thien; Nguyen, Vo Hoang; Chuong, Huynh Dinh; Tran, Le Bao; Tam, Hoang Duc; Binh, Nguyen Thi; Tao, Chau Van

2015-01-01

This article focuses on the possible application of a "1"3"7Cs low-radioactive source (5 mCi) and a NaI(Tl) detector for measuring the saturation thickness of solid cylindrical steel targets. In order to increase the reliability of the obtained experimental results and to verify the detector response function of Compton scattering spectrum, simulation using Monte Carlo N-particle (MCNP5) code is performed. The obtained results are in good agreement with the response functions of the simulation scattering and experimental scattering spectra. On the basis of such spectra, the saturation depth of a steel cylinder is determined by experiment and simulation at about 27 mm using gamma energy of 662 keV ("1"3"7Cs) at a scattering angle of 120°. This study aims at measuring the diameter of solid cylindrical objects by gamma-scattering technique. - Highlights: • This study aims a possible application a "1"3"7Cs low-radioactive source (5 mCi) and a NaI(Tl) detector for measuring the saturation thickness of solid cylindrical steel targets by gamma-scattering technique. • Monte Carlo N-particle (MCNP5) code is performed to verify on the detector response function of Compton scattering spectrum. • The results show a good agreement in response function of the experimental and simulation scattering spectra. • The saturation depth of a steel cylinder is determined by experiment and simulation at about 27 mm using gamma energy of 662 keV ("1"3"7Cs) at a scattering angle of 120°.

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.

Neutron Production in Spallation Reactions of 0.9 and 1.5 GeV Protons on a Thick Lead Target. Comparison between Experimental Data and Monte-Carlo Simulations

CERN Document Server

Krasa, A; Bradnova, V; Caloun, P; Chultem, D; Henzl, V; Henzlová, D; Kalinnikov, V G; Krivopustov, M I; Krízek, F; Kugler, A; Majerle, M; Solnyshkin, A A; Stegailov, V I; Tsoupko-Sitnikov, V M; Tumendelger, T; Vasilev, S I; Wagner, V; Nuclear Physics Institute of Academy of Sciences of Czech Republic, Rez, Czech Republic

2005-01-01

This paper reports on two experiments performed at the Synchrophasotron/Nuclotron accelerator complex at JINR. Relativistic protons with energies 885 MeV and 1.5 GeV hit a massive cylindrical lead target. The spatial and energetic distributions of the neutron field produced by the spallation reactions were measured by the activation of Al, Au, Bi, Co, and Cu foils placed on the surface of the target and close to it. The yields of the radioactive nuclei produced by threshold reactions in these foils were determined by the analyses of their $\\gamma$ spectra. The comparison with Monte-Carlo based simulations was performed both with the LAHET+MCNP code and the MCNPX code.

Neutron production in spallation reactions of 0.9 and 1.5 GeV protons on a thick lead target. Comparison between experimental data and Monte-Carlo simulations

International Nuclear Information System (INIS)

Krasa, A.; Krizek, F.; Wagner, V.; Kugler, A.; Henzl, V.; Henzlova, D.; Majerle, M.; Adam, J.; Caloun, P.; Bradnova, V.; Chultem, D.; Kalinnikov, V.G.; Krivopustov, M.I.; Solnyshkin, A.A.; Stegajlov, V.I.; Tsupko-Sitnikov, V.M.; Tumehndehlgehr, Ts.; Vasil'ev, S.I.

2005-01-01

This paper reports on two experiments performed at the Synchrophasotron/Nuclotron accelerator complex at JINR. Relativistic protons with energies 885 MeV and 1.5 GeV hit a massive cylindrical lead target. The spatial and energetic distributions of the neutron field produced by the spallation reactions were measured by the activation of Al, Au, Bi, Co, and Cu foils placed on the surface of the target and close to it. The yields of the radioactive nuclei produced by threshold reactions in these foils were determined by the analyses of their γ spectra. The comparison with Monte-Carlo based simulations was performed both with the LAHET+MCNP code and the MCNPX code

High energy density matter issues related to future circular collider. Simulations of full beam impact with a solid copper cylindrical target

Energy Technology Data Exchange (ETDEWEB)

Tahir, N.A. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Burkart, F.; Schmidt, R.; Wollmann, D. [CERN-AB, Geneva (Switzerland); Shutov, A. [Institute of Problems of Chemical Physics, Chernogolovka (Russian Federation); Piriz, A.R. [E.T.S.I. Industrials, University of Castilla-La Mancha, Ciudad Real (Spain)

2017-11-15

This paper presents numerical simulations of the thermodynamic and hydrodynamic response of a solid copper cylindrical target that is subjected to the full impact of one future circular collider (FCC) ultra-relativistic proton beam. The target is facially irradiated so that the beam axis coincides with the cylinder axis. The simulations have been carried out employing an energy deposition code, FLUKA, and a 2D hydrodynamic code, BIG2, iteratively. The simulations show that, although the static range of a single FCC proton and its shower in solid copper is ∝1.5 m, the full beam may penetrate up to 350 m into the target as a result of hydrodynamic tunnelling. Moreover, simulations also show that a major part of the target is converted into high energy density (HED) matter, including warm dense matter (WDM) and strongly coupled plasma. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

3D craniofacial registration using thin-plate spline transform and cylindrical surface projection.

Science.gov (United States)

Chen, Yucong; Zhao, Junli; Deng, Qingqiong; Duan, Fuqing

2017-01-01

Craniofacial registration is used to establish the point-to-point correspondence in a unified coordinate system among human craniofacial models. It is the foundation of craniofacial reconstruction and other craniofacial statistical analysis research. In this paper, a non-rigid 3D craniofacial registration method using thin-plate spline transform and cylindrical surface projection is proposed. First, the gradient descent optimization is utilized to improve a cylindrical surface fitting (CSF) for the reference craniofacial model. Second, the thin-plate spline transform (TPST) is applied to deform a target craniofacial model to the reference model. Finally, the cylindrical surface projection (CSP) is used to derive the point correspondence between the reference and deformed target models. To accelerate the procedure, the iterative closest point ICP algorithm is used to obtain a rough correspondence, which can provide a possible intersection area of the CSP. Finally, the inverse TPST is used to map the obtained corresponding points from the deformed target craniofacial model to the original model, and it can be realized directly by the correspondence between the original target model and the deformed target model. Three types of registration, namely, reflexive, involutive and transitive registration, are carried out to verify the effectiveness of the proposed craniofacial registration algorithm. Comparison with the methods in the literature shows that the proposed method is more accurate.

3D craniofacial registration using thin-plate spline transform and cylindrical surface projection.

Directory of Open Access Journals (Sweden)

Yucong Chen

Full Text Available Craniofacial registration is used to establish the point-to-point correspondence in a unified coordinate system among human craniofacial models. It is the foundation of craniofacial reconstruction and other craniofacial statistical analysis research. In this paper, a non-rigid 3D craniofacial registration method using thin-plate spline transform and cylindrical surface projection is proposed. First, the gradient descent optimization is utilized to improve a cylindrical surface fitting (CSF for the reference craniofacial model. Second, the thin-plate spline transform (TPST is applied to deform a target craniofacial model to the reference model. Finally, the cylindrical surface projection (CSP is used to derive the point correspondence between the reference and deformed target models. To accelerate the procedure, the iterative closest point ICP algorithm is used to obtain a rough correspondence, which can provide a possible intersection area of the CSP. Finally, the inverse TPST is used to map the obtained corresponding points from the deformed target craniofacial model to the original model, and it can be realized directly by the correspondence between the original target model and the deformed target model. Three types of registration, namely, reflexive, involutive and transitive registration, are carried out to verify the effectiveness of the proposed craniofacial registration algorithm. Comparison with the methods in the literature shows that the proposed method is more accurate.

Characterisation of target plasma required for REB-plasma interaction studies using cylindrical Langmuir probes

International Nuclear Information System (INIS)

Roychowdhury, P.; Paithankar, A.S.; Iyyengar, S.K.; Rohatgi, V.K.

1987-01-01

The target plasma required for relativistic electron beam (REB)-plasma interaction studies has been generated by coaxial plasma gun. The measurement of electron density and temperature has been carried out using cylindrical Langmuir probes. Probes both oriented parallel and transverse to the flow have been used. The spatial as well as temporal variation of electron density and temperature have been studied. The typical electron density and temperature measured by probe were in the range of 9.0-3.5 x 10 13 cm -3 and 5-7 eV respectively. The typical e-folding decay time of density was 6.2 μs, while no appreciable change in electron temperature was observed until 10 μs after the peak density. The density decays by about 50% at distance of 30 cm from the gun. The plasma flow velocity has been measured by the time of flight technique and was found to be 2.5 x 10 6 cm s -1 . The plasma radius measured by dosimeter film, at distance of 30 cm from the gun was 3 cm. (author)

An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

Energy Technology Data Exchange (ETDEWEB)

Ferdman, Alla

2005-05-11

The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no

A cylindrical specimen holder for electron cryo-tomography

International Nuclear Information System (INIS)

Palmer, Colin M.; Löwe, Jan

2014-01-01

The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the “missing wedge” problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future. - Highlights: • The missing wedge is a serious problem for electron cryo-tomography. • Cylindrical specimens allow the missing wedge to be eliminated. • Carbon nanopipettes can be used as cylindrical holders for tomography of frozen-hydrated specimens. • Cryo-tomography of cylindrical biological samples demonstrates a reduction of deleterious effects associated with the missing wedge

Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

International Nuclear Information System (INIS)

Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J.; Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.; Benlliure, J.; Casajeros, E.; Pereira, J.; Czajkowski, S.

2001-01-01

The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

Energy Technology Data Exchange (ETDEWEB)

Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J. [Paris-11 Univ., 91- Orsay (France). Inst. de Physique Nucleaire; Enqvist, T.; Armbruster, P.; Ricciardi, M.V.; Schmidt, K.H. [GSI, Planckstrasse 1, Darmstadt (Germany); Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91 - Gif sur Yvette (France); Benlliure, J.; Casajeros, E.; Pereira, J. [University of Santiago de Compostella (Spain); Czajkowski, S. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, CNRS-IN2P3, 33 - Gradignan (France)

2001-07-01

The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

Research on Radar Cross Section Measurement Based on Near-field Imaging of Cylindrical Scanning

Directory of Open Access Journals (Sweden)

Xing Shu-guang

2015-04-01

Full Text Available A new method of Radar Cross Section (RCS measurement based on near-field imaging of cylindrical scanning surface is proposed. The method is based on the core assumption that the target consists of ideal isotropic scattered centers. Three-dimensional radar scattered images are obtained by using the proposed method, and then to obtain the RCS of the target, the scattered far field is calculated by summing the fields generated by the equivalent scattered centers. Not only three dimensional radar reflectivity images but also the RCS of targets in certain three dimensional angle areas can be obtained. Compared with circular scanning that can only obtain twodimensional radar reflectivity images and RCS results in two-dimensional angle areas, cylindrical scanning can provide more information about the scattering properties of the targets. The method has strong practicability and its validity is verified by simulations.

Neutron production in interactions of relativistic protons and deuterons with lead targets

International Nuclear Information System (INIS)

Yurevich, V.I.; Amelin, N.S.; Yakovlev, R.M.; Nikolaev, V.A.; Lyapin, V.G.; Tsvetkov, I.O.

2005-01-01

Results on the neutron double-differential cross sections and yields obtained in the time-of-flight measurements with different lead targets and beams of protons and deuterons at an energy of about 2 GeV are discussed. The neutron spatial-energy distribution for an extended lead target was studied by the threshold detector method in the energy range of protons and deuterons 1-3.7 GeV. A dependence of the mean neutron multiplicity, energy of neutrons, and process of neutron multiplication in lead on the target dimension, and the type and energy of the beam particle is analyzed. (author)

Isotopically tailored lead target with reduced polonium and bismuth radio-waste

International Nuclear Information System (INIS)

Khorasanov, G.L.; Ivanov, A.P.; Lunev, V.P.; Blokhin, A.I.

2002-01-01

Residual activity of a lead target after 1 year irradiation with a high power, 0.8 GeV*30 mA, proton beam is studied. It is concluded that the main radiotoxicity of irradiated lead is connected with bismuth isotope, Bi-207, which is produced in natural lead, mix of several stable isotopes, via (p,2n) reaction with Pb-208 nuclei. It is proposed to use, as a target material, lead enriched with another stable isotope, Pb-206, in order to reduce producing Bi-207 and Po-210. Estimation of charges for obtaining large quantities of lead-206 is also given. Accumulation of hazardous radionuclides, Bi-207, Bi-208, and Po-210, in natural lead to be used as a coolant in future fast reactors and accelerator driven reactors is predicted. In accelerator driven systems a large portion of Bi-207 can be produced via Pb-208(p,2n)Bi-207 reaction in a target of natural lead (Pb-208/Pb-207/Pb-206/Pb-204=52.35/22.08/24.14/1.42 %). A new isotopically tailored coolant-converter for ADS consisting of lead isotope, Pb-206, is proposed. By using this material, it is possible to reduce essentially the production of the most radio-toxic isotopes of Bi and Po and to avoid disposing the large amounts of lead. To provide the future fast reactors and accelerator driven systems with low-activation coolant - converter, the new technology of obtaining the large amounts of natural lead enriched with lead isotope, Pb-206, should be developed. (authors)

An ISOLDE target unit

CERN Multimedia

Maximilien Brice

2002-01-01

A good dozen different targets are available for ISOLDE, made of different materials and equipped with different kinds of ion-sources, according to the needs of the experiments. Each separator (GPS: general purpose; HRS: high resolution) has its own target. Because of the high radiation levels, robots effect the target changes, about 80 times per year. In the standard unit shown in picture _01, the target is the cylindrical object in the front. It contains uranium-carbide kept at a temperature of 2200 deg C, necessary for the isotopes to be able to escape. At either end, one sees the heater current leads, carrying 700 A. The Booster beam, some 3E13 protons per pulse, enters the target from left. The evaporated isotope atoms enter a hot-plasma ion source (the black object behind the target). The whole unit sits at 60 kV potential (pulsed in synchronism with the arrival of the Booster beam) which accelerates the ions (away from the viewer) towards one of the 2 separators.

A new approach to the internal thermal management of cylindrical battery cells for automotive applications

Science.gov (United States)

Worwood, Daniel; Kellner, Quirin; Wojtala, Malgorzata; Widanage, W. D.; McGlen, Ryan; Greenwood, David; Marco, James

2017-04-01

Conventional cooling approaches that target either a singular tab or outer surface of common format cylindrical lithium-ion battery cells suffer from a high cell thermal resistance. Under an aggressive duty cycle, this resistance can result in the formation of large in-cell temperature gradients and high hot spot temperatures, which are known to accelerate ageing and further reduce performance. In this paper, a novel approach to internal thermal management of cylindrical battery cells to lower the thermal resistance for heat transport through the inside of the cell is investigated. The effectiveness of the proposed method is analysed for two common cylindrical formats when subject to highly aggressive electrical loading conditions representative of a high performance electric vehicle (EV) and hybrid electric vehicle (HEV). A mathematical model that captures the dominant thermal properties of the cylindrical cell is created and validated using experimental data. Results from the extensive simulation study indicate that the internal cooling strategy can reduce the cell thermal resistance by up to 67.8 ± 1.4% relative to single tab cooling, and can emulate the performance of a more complex pack-level double tab cooling approach whilst targeting cooling at a single tab.

Cylindrical implosion to measure the radiative properties of high density and temperature plasmas

International Nuclear Information System (INIS)

Xu Yan; Rose, S.J.

2000-01-01

Cylindrical implosion is of great interest because of its excellent diagnostic access. The authors present one-dimensional numerical simulations to explore the plasma conditions that may be achieved. Combined with the numerical data, the development of Rayleigh-Taylor instabilities and Richtmyer-Meshkov instabilities in those targets are estimated. The authors found that it is possible to achieve a high density and temperature plasma with a relatively low temperature and density gradient using a cylindrical implosion directly-driven by a high-power laser

Lithium beam characterization of cylindrical PBFA II hohlraum experiments

International Nuclear Information System (INIS)

Moats, A.R.; Derzon, M.S.; Chandler, G.A.; Haill, T.A.; Johnson, D.J.; Leeper, R.J.; Ruiz, C.L.; Wenger, D.F.

1995-01-01

Sandia National Laboratories is actively engaged in exploring indirect-drive inertial confinement fusion on the Particle Beam Fusion Accelerator (PBFA II) with pulsed-power accelerated lithium ions as the driver. Experiments utilizing cylindrical hohlraum targets were conducted in 1994. Using the incoming ion beam-induced line radiation from titanium wires surrounding these hohlraums, beam profiles during these experiments have been measured and characterized. These data, their comparison/cross-correlation with particle-based beam diagnostics, and an analysis of the beam parameters that most significantly influence target temperature are presented

Telescoping cylindrical piezoelectric fiber composite actuator assemblies

Science.gov (United States)

Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

2010-01-01

A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

77 FR 16796 - Lead Requirements for Lead-Based Paint Activities in Target Housing and Child-Occupied Facilities...

Science.gov (United States)

2012-03-22

... document announces the receipt of Arkansas's rules established pursuant to its new 2011 statutory authority... program accreditation requirements, and work practice standards for lead-based paint activities in target...-based paint program and passed a new statute establishing a State lead-based paint program and changing...

90 deg.Neutron emission from high energy protons and lead ions on a thin lead target

CERN Document Server

Agosteo, S; Foglio-Para, A; Mitaroff, W A; Silari, Marco; Ulrici, L

2002-01-01

The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: sup 2 sup 0 sup 8 Pb sup 8 sup 2 sup + lead ions at 40 GeV/c per nucleon and 158 GeV/c per nucleon, and 40 GeV/c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90 deg.with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that--for such high energy heavy ion beams--a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0...

Current distribution over the electrode surface in a cylindrical VRLA cell during discharge

Czech Academy of Sciences Publication Activity Database

Křivák, P.; Bača, P.; Calábek, M.; Micka, Karel; Král, P.

2006-01-01

Roč. 154, č. 2 (2006), s. 518-522 ISSN 0378-7753 Grant - others:Advanced Lead-Acid Battery Consortium(ES) N4.2 Institutional research plan: CEZ:AV0Z40400503 Keywords : grid design * current distribution * cylindrical lead-acid cell Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.521, year: 2006

Pulling cylindrical particles using a soft-nonparaxial tractor beam

DEFF Research Database (Denmark)

Novitsky, Andrey; Ding, Weiqiang; Wang, Maoyan

2017-01-01

In order to pull objects towards the light source a single tractor beam inevitably needs to be strongly nonparaxial. This stringent requirement makes such a tractor beam somewhat hypothetical. Here we reveal that the cylindrical shape of dielectric particles can effectively mitigate the nonparaxi......In order to pull objects towards the light source a single tractor beam inevitably needs to be strongly nonparaxial. This stringent requirement makes such a tractor beam somewhat hypothetical. Here we reveal that the cylindrical shape of dielectric particles can effectively mitigate...... the nonparaxiality requirements, reducing the incidence angle of the partial plane waves of the light beam down to 45 degrees and even to 30 degrees for respectively dipole and dipole-quadrupole objects. The optical pulling force attributed to the interaction of magnetic dipole and magnetic quadrupole moments...... and sorting of targeted particles....

Assistant in design of tissue targeting leads with radio-combinatorial screening vivo

International Nuclear Information System (INIS)

Liu Ciyi; Zeng Jun; Xie Wenhui; Hu Silong; Jin Muxiu

2004-01-01

The diagnostic and therapeutic efficiency of drug depends highly on the drug distribution in target tissues (tumor for example) both specifically and accumulatively. We report here a powerful approach in design of tissue targeting leads with the assistant of radio-combinatorial screening technique developed in our laboratory. Methods: The C-terminal amide tripeptide libraries were synthesized on Rink Amide-MBHA resin in the OXX aO1OXaO1O2O positional scanning format and iterative protoco. A technetium (V) oxo core[(TcO)3+] was bound to the N4-triligands of tripeptide libraries via four deprotonated anfide nitrogen atoms to form a structure of 99Tcm-tripeptoid libraries. The radio-combinatorial screening (RCS) in vivo was then carried out after SD rats and A549 tumor bearing mice received i.v. with 99Tcm-tripeptoid libraries. Results: Signals of tissue distribution and metabolism of libraries were recorded by g counting or imaging. From library of 8,000 99Tcm-tripeptoid members, the tissue targeting leads had been identified by RCS. Those included 99Tcm-DSG (RES), 99Tcm-VAA, and 99Tcm-VIG that had specific tissue targeting in kidney, stomach, and liver respectively. The percent injected dose per gram tissue (%ID/g) of 99Tcm labeled leads in their target tissues was highly structure-dependent The discovery of 99Tcm-VAA and 99Tcm-VIG indicates that side chain methyl at positionl and 2 are crucial for stomach and liver accumulating 99Tcm-tripeptoids. In the case of kidney targeting, Ser in the position 2 and 3 is crucial for 99Tcm-tripeptoids renal excretion and accumulation characteristics respectively. Conclusion: RCS in vivo is a powerful tool for design of tissue targeting leads. (authors)

Cylindrical fabric-confined soil structures

Science.gov (United States)

Harrison, Richard A.

A cylindrical fabric-soil structural concept for implementation on the moon and Mars which provides many advantages is proposed. The most efficient use of fabric is to fashion it into cylindrical tubes, creating cylindrical fabric-confined soil structures. The length, diameter, and curvature of the tubes will depend on the intended application. The cylindrical hoop forces provide radial confinement while end caps provide axial confinement. One of the ends is designed to allow passage of the soil into the fabric tube before sealing. Transportation requirements are reduced due to the low mass and volume of the fabric. Construction requirements are reduced due to the self-erection capability via the pneumatic exoskeleton. Maintenance requirements are reduced due to the passive nature of the concept. The structure's natural ductility is well suited for any seismic activity.

Analytical solution for the transport equation for neutral particles in cylindrical and Cartesian geometry

International Nuclear Information System (INIS)

Goncalves, Glenio Aguiar

2003-01-01

In this work, we are reported analytical solutions for the transport equation for neutral particles in cylindrical and cartesian geometry. For the cylindrical geometry, it is applied the Hankel transform of order zero in the S N approximation of the one-dimensional cylindrical transport equation, assuming azimuthal symmetry and isotropic scattering. This procedure is coined HTSN method. The anisotropic problem is handled using the decomposition method, generating a recursive approach, which the HTSN solution is used as initial condition. For cartesian geometry, the one and two dimensional transport equation is derived in the angular variable as many time as the degree of the anisotropic scattering. This procedure leads to set of integro-differential plus one differential equation that can be really solved by the variable separation method. Following this procedure, it was possible to come out with the Case solution for the one-dimensional problem. Numerical simulations are reported for the cylindrical transport problem both isotropic and anisotropic case of quadratic degree. (author)

Determination of the shapes and sizes of the regions in which in hadron-nucleus collisions reactions leading to the nucleon emission, particle production, and fragment evaporation occur

International Nuclear Information System (INIS)

Strugalski, Z.

1985-01-01

Shapes and sizes of the regions in target-nuclei in which reactions leading to the nucleon emission, particle production and fragment evaporation occur are determined. The region of nucleon emission is of cylindrical shape, with the diameter as large as two nucleon diameters, centered on the incident hadron course. The reactions leading to the particle production happen predominantly along the incident hadron course in nuclear matter. The fragment evaporation goes from the surface layer of the part of the target-nucleus damaged in nucleon emission process

Measured radionuclide production from copper, gold and lead spallation targets

Energy Technology Data Exchange (ETDEWEB)

Parish, T.A.; Belian, A.P. [Texas A & M Univ., College Station, TX (United States)

1995-10-01

Spallation target materials are chosen so as to produce large numbers of neutrons while at the same time avoiding the creation of long-lived radioactive wastes. While there has been considerable research to determine the number of neutrons produced per incident particle for various target materials, there has been less effort to precisely quantify the types and amounts of radionuclides produced. Accurate knowledge of the radioactive species produced by spallation reactions is important for specifying waste disposal criteria for targets. In order to verify the production rates calculated by LAHET, a study has been conducted using the Texas A&M University (TAMU) Cyclotron to measure radionuclide yields from copper, gold, and lead targets.

Cylindrical polymer brushes with dendritic side chains by iterative anionic reactions

KAUST Repository

Zhang, Hefeng

2015-05-01

We report in this paper an easy method for the synthesis of cylindrical polymer brushes with dendritic side chains through anionic reaction. The synthesis is accomplished by iteratively grafting a living block copolymer, polyisoprene-. b-polystyrenyllithium (PI-. b-PSLi), to the main chain and subsequently to the branches in a divergent way. PI segment is short and serves as a precursor for multifunctional branching unit. The grafting reaction involves two successive steps: i) epoxidation of internal double bonds of PI segments, either in main chain or side chains; ii) ring-opening addition to the resulting epoxy group by the living PI-. b-PSLi. Repeating the two steps affords a series of cylindrical polymer brushes with up to 3rd generation and extremely high molecular weight. The branching multiplicity depends on the average number of oxirane groups per PI segment, usually ca. 8 in the present work. The high branching multiplicity leads to tremendous increase in molecular weights of the cylindrical products with generation growth. Several series of cylindrical polymer brushes with tunable aspect ratios are prepared using backbones and branches with controlled lengths. Shape anisotropy is investigated in dilute solution using light scattering technique. Worm-like single molecular morphology with large persistence length is observed on different substrates by atomic force microscopy.

The space distribution of neutrons generated in massive lead target by relativistic nuclear beam

International Nuclear Information System (INIS)

Chultem, D.; Damdinsuren, Ts.; Enkh-Gin, L.; Lomova, L.; Perelygin, V.; Tolstov, K.

1993-01-01

The present paper is devoted to implementation of solid state nuclear track detectors in the research of the neutron generation in extended lead spallation target. Measured neutrons space distribution inside the lead target and neutron distribution in the thick water moderator are assessed. (Author)

Selection of flowing liquid lead target structural materials for accelerator driven transmutation applications

International Nuclear Information System (INIS)

Park, J.J.; Buksa, J.J.

1994-01-01

The beam entry window and container for a liquid lead spallation target will be exposed to high fluxes of protons and neutrons that are both higher in magnitude and energy than have been experienced in proton accelerators and fission reactors, as well as in a corrosive environment. The structural material of the target should have a good compatibility with liquid lead, a sufficient mechanical strength at elevated temperatures, a good performance under an intense irradiation environment, and a low neutron absorption cross section; these factors have been used to rank the applicability of a wide range of materials for structural containment Nb-1Zr has been selected for use as the structural container for the LANL ABC/ATW molten lead target. Corrosion and mass transfer behavior for various candidate structural materials in liquid lead are reviewed, together with the beneficial effects of inhibitors and various coatings to protect substrate against liquid lead corrosion. Mechanical properties of some candidate materials at elevated temperatures and the property changes resulting from 800 MeV proton irradiation are also reviewed

Waves in inhomogeneous plasma of cylindrical geometry

International Nuclear Information System (INIS)

Rebut, P.H.

1966-01-01

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) [fr

Status and future application of pilot lead-bismuth target circuit TC-1 for ADS

Energy Technology Data Exchange (ETDEWEB)

Ignatiev, S.; Leonchuk, M.; Orlov, Y.; Pankratov, D.; Reshetnikova, O.; Suvorov, G.; Zabudko, A. [Institute for Physics and Power Engineering, Obninsk (Russian Federation); Stepanov, V.; Klimov, N. [Experimental and Design Organization, Gidropress, Podolsk (Russian Federation); Hechanova, A.; Ma, J. [Nevada Univ., Las Vegas, NV (United States); Li, N. [Los Alamos National Lab., NM (United States); Gudowski, W. [International Science and Technology Center, Moscow (Russian Federation)

2007-07-01

A complicated evolution, status and future application of the pilot molten lead-bismuth target circuit of 1 MW proton beam power (TC-1) as an important part of a target-blanket accelerator driven system (ADS), that has been developed, created and twice tested under the auspice of the International Science and Technology Center (ISTC), is analyzed. The target complex TC-1 is a circulation lead-bismuth loop whose beam window is made of ferritic steel EP-823 (this steel was used in the past as material of fuel rods cladding in reactors cooled with lead-bismuth). At present TC-1 is operating at coolant temperature up to 300 C degrees and will be used to study different issues linked to the use of lead-bismuth: -) interaction with air, water and hydrogen, -) different regimes of flow, -) corrosion, -) filtering, or -) slag formation.

Cylindrical-shaped nanotube field effect transistor

KAUST Repository

Hussain, Muhammad Mustafa; Fahad, Hossain M.; Smith, Casey E.; Rojas, Jhonathan Prieto

2015-01-01

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.

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.

Parametric studies of target/moderator configurations for the Weapons Neutron Research (WNR) facility

International Nuclear Information System (INIS)

Russell, G.J.; Seeger, P.A.; Fluharty, R.G.

1977-03-01

Parametric studies, using continuous-energy Monte Carlo codes, were done to optimize the neutronics of the Weapons Neutron Research (WNR) target and three possible target/moderator configurations: slab target/slab moderators, cylindrical target/cylindrical moderator, and cylindrical target/double-wing moderators. The energy range was 0.5 eV to 800 MeV. A general figure-of-merit (FOM) approach was used. The WNR facility performance can be doubled or tripled by optimizing the target and target/moderator configurations; this approach is more efficient than increasing the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator power by an equivalent factor. A bare target should be used for neutron energies above approximately 100 keV. The FOM for the slab target/slab moderator configuration is the best by a factor of at least 2 to 3 below approximately 1 keV. The total neutron leakage from 0.5 eV to 100 keV through a 100- by 100-mm area centered at the peak leakage is largest for the slab moderator, exceeding that of the cylindrical moderator and double-wing moderator by factors of 1.7 and 3.4, respectively. The neutron leakage at 1 eV from one 300- by 150-mm surface of a slab moderator is 1.5 times larger than that from one 155- by 150-mm surface of a cylindrical moderator. When compared with the 1-eV leakage from two 100- by 150-mm surfaces of a double-wing moderator, that from the slab moderator is 3.4 times larger. 107 figures, 13 tables

Analysis of a cylindrical shell vibrating in a cylindrical fluid region

International Nuclear Information System (INIS)

Chung, H.; Turula, P.; Mulcahy, T.M.; Jendrzejczyk, J.A.

1976-08-01

Analytical and experimental methods are presented for evaluating the vibration characteristics of cylindrical shells such as the thermal liner of the Fast Flux Test Facility (FFTF) reactor vessel. The NASTRAN computer program is used to calculate the natural frequencies, mode shapes, and response to a harmonic loading of a thin, circular cylindrical shell situated inside a fluid-filled rigid circular cylinder. Solutions in a vacuum are verified with an exact solution method and the SAP IV computer code. Comparisons between analysis and experiment are made, and the accuracy and utility of the fluid-solid interaction package of NASTRAN is assessed

Stability of cylindrical thin shell wormhole during evolution of universe from inflation to late time acceleration

Energy Technology Data Exchange (ETDEWEB)

Setare, M.R. [Department of Science, Campus of Bijar, University of Kurdistan,Bijar (Iran, Islamic Republic of); Sepehri, A. [Faculty of Physics, Shahid Bahonar University,P.O. Box 76175, Kerman (Iran, Islamic Republic of)

2015-03-16

In this paper, we consider the stability of cylindrical wormholes during evolution of universe from inflation to late time acceleration epochs. We show that there are two types of cylindrical wormholes. The first type is produced at the corresponding point where k black F-strings are transited to BIon configuration. This wormhole transfers energy from extra dimensions into our universe, causes inflation, loses it’s energy and vanishes. The second type of cylindrical wormhole is created by a tachyonic potential and causes a new phase of acceleration. We show that wormhole parameters grow faster than the scale factor in this era, overtake it at ripping time and lead to the destruction of universe at big rip singularity.

Performance Analysis of Functionally Graded Coatings in Contact with Cylindrical Rollers

Directory of Open Access Journals (Sweden)

Reza Jahedi

2015-01-01

Full Text Available This work presents finite element analysis (FEA and results for rolling contact of a cylindrical roller on an elastic substrate coated by functionally graded material (FGM. The rolling process and the graded coating material property and layers arrangement are modeled using finite element codes which lead to a new methodology. This novel methodology provides a trend in determining surface contact stresses, deformations, contact zones, and energy dissipation through the contact area. Effects of stiffness ratio, friction, and exponentially variation of material property on the contact stresses and deformations are studied. Some of the results are verified with analytical solutions. The study results may be beneficial in graded coated cylindrical components analysis against rolling contact failure and wear.

Cylindrical acoustic levitator/concentrator

Science.gov (United States)

Kaduchak, Gregory; Sinha, Dipen N.

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.

The electrostatic cylindrical sheath in a plasma

International Nuclear Information System (INIS)

Wang Chunhua; Sun Xiaoxia; Bai Dongxue

2004-01-01

The electrostatic sheath with a cylindrical geometry in an ion-electron plasma is investigated. Assuming a Boltzmann response to electrons and cold ions with bulk flow, it is shown that the radius of the cylindrical geometry do not affect the sheath potential significantly. The authors also found that the sheath potential profile is steeper in the cylindrical sheath compared to the slab sheath. The distinct feature of the cylindrical sheath is that the ion density distribution is not monotonous. The sheath region can be divided into three regions, two ascendant regions and one descendant region. (author)

Homotheties of cylindrically symmetric static spacetimes

International Nuclear Information System (INIS)

Qadir, A.; Ziad, M.; Sharif, M.

1998-08-01

In this note we consider the homotheties of cylindrically symmetric static spacetimes. We find that we can provide a complete list of all metrics that admit non-trivial homothetic motions and are cylindrically symmetric static. (author)

2-D simulation of hohlraum targets for HIDIF: gold vs. beryllium converters

International Nuclear Information System (INIS)

Honrubia, J.J.; Meyer-ter-Vehn, J.

2000-01-01

Two cylindrical hohlraum targets for heavy-ion-fusion are compared from the point of view of total ion-energy required to ignite a specified capsule. Target a, a simple bare gold cylindrical cavity behaves much more efficiently than Target b, the former one internally cladded with solid beryllium where convenient, to ensure ion energy conversion to X-rays mainly in this cladding. A discussion of the problem is provided. (authors)

Spallation neutron source target design for radioactive waste transmutation

International Nuclear Information System (INIS)

Beard, C.A.

1992-01-01

The disposal of high-level radioactive waste has long been one of the most serious problems facing the nuclear industry. Transmutation of this waste through particle bombardment has been suggested numerous times as a possible method of enhancing the waste management process. Due to advances in accelerator technology, the feasibility of an accelerator based transmutation system has increased enough to allow serious investigation of this process. Therefore, in pursuit of this goal, an accelerator target was designed for use in an accelerator based transmutation system. The target design consists of an array of tantalum rods, cooled by liquid sodium, which are arranged in a cylindrical configuration 40 cm in diameter and 125 cm in height. Tantalum was chosen as the target material over tungsten, lead, bismuth, and a lead-bismuth alloy (55 w/o bismuth) due to a large neutron yield, low activation, low chemical toxicity, and the fact that it does not produce significant amounts of long-lived isotopes through spallation or activation. The target yields a neutron source of 29.7 neutrons/proton when exposed to a 1600 MeV proton beam, and is suitable for use with both thermal or fast spectrum transmutation systems

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.

A miniaturised, nested-cylindrical electrostatic analyser geometry for dual electron and ion, multi-energy measurements

Energy Technology Data Exchange (ETDEWEB)

Bedington, Robert, E-mail: r.bedington@nus.edu.sg; Kataria, Dhiren; Smith, Alan

2015-09-01

The CATS (Cylindrical And Tiny Spectrometer) electrostatic optics geometry features multiple nested cylindrical analysers to simultaneously measure multiple energies of electron and multiple energies of ion in a configuration that is targeted at miniaturisation and MEMS fabrication. In the prototyped model, two configurations of cylindrical analyser were used, featuring terminating side-plates that caused particle trajectories to either converge (C type) or diverge (D type) in the axial direction. Simulations show how these different electrode configurations affect the particle focussing and instrument parameters; C-type providing greater throughputs but D-type providing higher resolving powers. The simulations were additionally used to investigate unexpected plate spacing variations in the as-built model, revealing that the k-factors are most sensitive to the width of the inter-electrode spacing at its narrowest point. - Highlights: • A new nested cylindrical miniaturised electrostatic analyser geometry is described. • “Converging” (C) and “diverging” (D) type channel properties are investigated. • C channels are shown to have greater throughputs and D greater resolving powers. • Plate factors are shown to be sensitive to the minimum in inter-electrode spacing.

Performance of a liquid argon electromagnetic calorimeter with a cylindrical accordion geometry

International Nuclear Information System (INIS)

Aubert, B.; Bazan, A.; Beaugiraud, B.; Colas, J.; Leflour, T.; Maire, M.; Vialle, J.P.; Wingerter-Seez, I.; Zolnierowski, Y.P.; Gordon, H.A.; Radeka, V.; Rahm, D.; Stephani, D.; Bulgakov, N.; Chevalley, J.L.; Fabjan, C.W.; Fournier, D.; Gildemeister, O.; Jenni, P.; Nessi, M.; Nessi-Tedaldi, F.; Pepe, M.; Richter, W.; Soderqvist, J.; Vuillemin, V.; Baze, J.M.; Gosset, L.; Lavocat, P.; Lottin, J.P.; Mansoulie, B.; Meyer, J.P.; Renardy, J.R.; Teiger, J.; Zaccone, H.; Battistoni, G.; Camin, D.V.; Cavalli, D.; Costa, G.; Cravero, A.; Ferrari, A.; Gianotti, F.; Mandelli, L.; Mazzanti, M.; Perini, L.; Sciamanna, M.; Auge, E.; Chase, R.; Chollet, J.C.; La Taille, C. de; Fayard, L.; Hrisoho, A.; Jean, P.; Iconomidou-Fayard, L.; Le Meur, G.; Merkel, B.; Noppe, J.M.; Parrour, G.; Petroff, P.; Repellin, J.P.; Schaffer, A.; Seguin, N.; Unal, G.; Fuglesang, C.; Lefebvre, M.

1993-01-01

A prototype of a lead liquid argon accordion calorimeter with two types of cylindrical geometry was constructed and equipped with high speed readout electronics. The energy resolution for electrons is 10%/√E (GeV) with a local constant term of 0.65%. The resolutions obtained for position and angular measurements are given. (orig.)

Therapeutic analysis of high-dose-rate {sup 192}Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hualin, E-mail: hualin.zhang@northwestern.edu; Donnelly, Eric D.; Strauss, Jonathan B. [Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois 60611 (United States); Qi, Yujin [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

2016-01-15

Purpose: To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. Methods: A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model was used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. Results: EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0){sup 4} to (13

Calculation of the effective D-d neutron energy distribution incident on a cylindrical shell sample

International Nuclear Information System (INIS)

Gotoh, Hiroshi

1977-07-01

A method is proposed to calculate the effective energy distribution of neutrons incident on a cylindrical shell sample placed perpendicularly to the direction of the deuteron beam bombarding a deuterium metal target. The Monte Carlo method is used and the Fortran program is contained. (auth.)

Magnetostatic interactions and forces between cylindrical permanent magnets

International Nuclear Information System (INIS)

Vokoun, David; Beleggia, Marco; Heller, Ludek; Sittner, Petr

2009-01-01

Permanent magnets of various shapes are often utilized in magnetic actuators, sensors or releasable magnetic fasteners. Knowledge of the magnetic force is required to control devices reliably. Here, we introduce an analytical expression for calculating the attraction force between two cylindrical permanent magnets on the assumption of uniform magnetization. Although the assumption is not fulfilled exactly in cylindrical magnets, we obtain a very good agreement between the calculated and measured forces between two identical cylindrical magnets and within an array of NdFeB cylindrical magnets.

Sound radiation modes of cylindrical surfaces and their application to vibro-acoustics analysis of cylindrical shells

Science.gov (United States)

Sun, Yao; Yang, Tiejun; Chen, Yuehua

2018-06-01

In this paper, sound radiation modes of baffled cylinders have been derived by constructing the radiation resistance matrix analytically. By examining the characteristics of sound radiation modes, it is found that radiation coefficient of each radiation mode increases gradually with the increase of frequency while modal shapes of sound radiation modes of cylindrical shells show a weak dependence upon frequency. Based on understandings on sound radiation modes, vibro-acoustics behaviors of cylindrical shells have been analyzed. The vibration responses of cylindrical shells are described by modified Fourier series expansions and solved by Rayleigh-Ritz method involving Flügge shell theory. Then radiation efficiency of a resonance has been determined by examining whether the vibration pattern is in correspondence with a sound radiation mode possessing great radiation efficiency. Furthermore, effects of thickness and boundary conditions on sound radiation of cylindrical shells have been investigated. It is found that radiation efficiency of thicker shells is greater than thinner shells while shells with a clamped boundary constraint radiate sound more efficiently than simply supported shells under thin shell assumption.

Lead telluride with increased mechanical stability for cylindrical thermoelectric generators

International Nuclear Information System (INIS)

Schmitz, Andreas

2013-01-01

The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb 1-x Ca x Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric properties

Theory and modeling of cylindrical thermo-acoustic transduction

Energy Technology Data Exchange (ETDEWEB)

Tong, Lihong, E-mail: lhtong@ecjtu.edu.cn [School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi (China); Lim, C.W. [Department of Architecture and Civil Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Zhao, Xiushao; Geng, Daxing [School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi (China)

2016-06-03

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. - Highlights: • Theory and modeling both for solid and thinfilm-solid cylindrical thermo-acoustic transductions are proposed. • The modeling is verified by comparing with the published experimental data. • Acoustic response characteristics of cylindrical thermo-acoustic transductions are predicted by the proposed model.

A Time-Space Symmetry Based Cylindrical Model for Quantum Mechanical Interpretations

Science.gov (United States)

Vo Van, Thuan

2017-12-01

Following a bi-cylindrical model of geometrical dynamics, our study shows that a 6D-gravitational equation leads to geodesic description in an extended symmetrical time-space, which fits Hubble-like expansion on a microscopic scale. As a duality, the geodesic solution is mathematically equivalent to the basic Klein-Gordon-Fock equations of free massive elementary particles, in particular, the squared Dirac equations of leptons. The quantum indeterminism is proved to have originated from space-time curvatures. Interpretation of some important issues of quantum mechanical reality is carried out in comparison with the 5D space-time-matter theory. A solution of lepton mass hierarchy is proposed by extending to higher dimensional curvatures of time-like hyper-spherical surfaces than one of the cylindrical dynamical geometry. In a result, the reasonable charged lepton mass ratios have been calculated, which would be tested experimentally.

Optimization of Cylindrical Hall Thrusters

International Nuclear Information System (INIS)

Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fisch, Nathaniel J.

2007-01-01

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.

Optimization of Cylindrical Hall Thrusters

International Nuclear Information System (INIS)

Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fi, Nathaniel J.

2007-01-01

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

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.

Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene

Energy Technology Data Exchange (ETDEWEB)

Faugeras, P E [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Groupe de recherches sur la fusion controlee

1967-07-01

The problem of the scattering of plane electromagnetic waves from a non-uniform, cylindrically symmetrical plasma is solved analytically, by a self-consistent field method, for a wave with the electric field parallel to the cylinder axis. Numerical results for the diffracted field are plotted for interesting ranges of the parameters involved: diameter, density on the axis, radial profile of the density, and collision frequencies. The case where the incident field is cylindric (waves surfaces parallel to the cylinder axis) is examined - this permits to connect theoretical calculations and experimental diffraction patterns, and also to explain the diffraction effects observed in a classical microwave interferometry experiment. These results, and the possibility of measuring exactly the diffracted field (showed by experiments with dielectric and metallic rods) lead to a new plasma diagnostic method, based on the diffraction, which has no theoretical limitations and it usable when the classical free-space wave methods are not (plasma diameter lower than 10 wave lengths). The feasibility of this method is tested with a plasma at atmospheric pressure and a 2 mm incident wavelength. The plasma is obtained by the laminar flow of a plasma torch, with a working gas (He or Ar) seeded by potassium (density continuously variable between 10{sup 11} and 10{sup 15} e/cm{sup 3}. Some diffraction patterns by this plasma and for various incident waves, are also given and explained with theoretical calculations. (author) [French] On etudie la diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene par une methode de champ self-consistant, et pour une onde de vecteur electrique parallele a l'axe du cylindre. On a calcule le champ diffracte en faisant varier le diametre du cylindre, la densite sur l'axe, le profil de densite et les frequences de collisions, et on donne ici les principaux resultats. On examine ensuite le cas d'une onde incidente cylindrique

Neutron production from 158 GeV/c per nucleon lead ions on thin copper and lead targets in the angular range 30-135 deg

CERN Document Server

Agosteo, S; Foglio-Para, A; Gini, L; Mitaroff, W A; Silari, Marco; Ulrici, L

2002-01-01

The neutron emission from 5, 10 and 20 mm thick lead and 10 and 20 mm thick copper targets bombarded by a lead ion beam with momentum of 158 GeV/c per nucleon were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident ion on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 deg. with respect to beam direction. Monte Carlo simulations with the FLUKA code were performed to establish a guess spectrum for the unfolding of the experimental data. The results have shown that, lacking Monte Carlo radiation transport codes dealing with ions with masses larger than 1 amu, a reasonable prediction can be carried out by scaling the result of a Monte Carlo calculation for protons by the projectile mass number to the power of 0.85-0.95 for a lead target and 0.88-1.03 for a copper target.

Results from beam tests of MEGA's low-mass, high-rate cylindrical MWPCs

International Nuclear Information System (INIS)

Stanislaus, S.; Armijo, V.; Black, J.K.; Bolton, R.D.; Carius, S.; Cooper, M.D.; Espinoza, C.; Hart, G.; Hogan, G.; Gonzales, A.; Mischke, R.E.; Piilonen, L.E.; Sandoval, J.; Schilling, S.; Sena, J.; Suazo, G.; Szymanski, J.J.; Whitehouse, D.A.; Wilkinson, C.A.; Fisk, R.; Koetke, D.D.; Manweiler, R.W.; Jui, C.C.

1991-01-01

One of the leading experimental projects at LAMPF has been the MEGA experiment. This is an experiment to search for the rare decay μ → eγ with a sensitivity of 10 -13 . A prime component of this project has been the design and construction of high-rate, low mass MWPCs for the tracking of positrons from muon decay. With rate capabilities of 2 x 10 4 e + /mm 2 /s and a thickness of 3 x 10 -4 radiation lengths, these chambers are state-of-the-art cylindrical MWPCs. Cylindrical chambers of this size (0.9 m 2 ) and thinness have never been previously constructed. The MEGA project at LAMPF has recently succeeded in building chambers with these necessary performance characteristics as demonstrated by data taken from muon decays, cosmic rays, and sources

Cylindrical and Spherical Active Coated Nanoparticles as Nanoantennas: Active nanoparticles as nanoantennas

DEFF Research Database (Denmark)

Arslanagic, Samel; Ziolkowski, Richard W.

2017-01-01

In this article, we review the fundamental properties of several spherical and cylindrical, passive, and active coated nanoparticles (CNPs) with an emphasis on their potential for nanoantenna and nanoamplifier synthesis. For the spherical geometries, the nanoparticles are excited by an electric...... Hertzian dipole (EHD), which represents, e.g., a stimulated atom or molecule. The cylindrical nanoparticles are excited by a magnetic line source (MLS). In the active cases, gain is added to the core region of the particle. For simplicity, it is represented by a canonical, frequency-independent gain model....... We demonstrate that specific CNPs can be designed to be resonant and well matched to their respective excitation sources. With active cores, these designs can lead to extremely large total radiated powers. For both configurations, insights into the effects of the nanoparticle material composition...

Therapeutic analysis of high-dose-rate "1"9"2Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions

International Nuclear Information System (INIS)

Zhang, Hualin; Donnelly, Eric D.; Strauss, Jonathan B.; Qi, Yujin

2016-01-01

Purpose: To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. Methods: A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model was used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. Results: EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0)"4 to (13.4)"4 for

On isotropic cylindrically symmetric stellar models

International Nuclear Information System (INIS)

Nolan, Brien C; Nolan, Louise V

2004-01-01

We attempt to match the most general cylindrically symmetric vacuum spacetime 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 relation to recent results about the impossibility of the static axially symmetric analogue of the Einstein-Straus model

MicroRNA-target gene responses to lead-induced stress in cotton (Gossypium hirsutum L.).

Science.gov (United States)

He, Qiuling; Zhu, Shuijin; Zhang, Baohong

2014-09-01

MicroRNAs (miRNAs) play key roles in plant responses to various metal stresses. To investigate the miRNA-mediated plant response to heavy metals, cotton (Gossypium hirsutum L.), the most important fiber crop in the world, was exposed to different concentrations (0, 25, 50, 100, and 200 µM) of lead (Pb) and then the toxicological effects were investigated. The expression patterns of 16 stress-responsive miRNAs and 10 target genes were monitored in cotton leaves and roots by quantitative real-time PCR (qRT-PCR); of these selected genes, several miRNAs and their target genes are involved in root development. The results show a reciprocal regulation of cotton response to lead stress by miRNAs. The characterization of the miRNAs and the associated target genes in response to lead exposure would help in defining the potential roles of miRNAs in plant adaptation to heavy metal stress and further understanding miRNA regulation in response to abiotic stress.

Analysis of the Neutron Generator and Target for the LSDTS System

Energy Technology Data Exchange (ETDEWEB)

Park, Chang Je; Lee, Yong Deok; Song, Jae Hoon; Song, Kee Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2008-11-15

A preliminary analysis was performed based on the literatures and the patents for the neutron generators and targets for the lead slowing down time spectrometer (LSDTS) system. It was found that local neutron generator did not exhibit enough neutron intensity such as 1E+12 n/s, which is a minimum requirement for the LSDTS system to overcome curium backgrounds. However, a neutron generator implemented with an electron accelerator may provide a higher intensity around 1E+13 n/s and it is required to investigate further including a detail analysis. In addition to the neutron generator, a study on target was performed with the Monte Carlo simulation. In the study, an optimal design of target was suggested to provide a high neutron yield and a better thermal resistance. The suggested target consists several cylindrical plates with a certain cooling gap, which have increasing thickness and increasing radius.

Bio-Inspired Wide-Angle Broad-Spectrum Cylindrical Lens Based on Reflections from Micro-Mirror Array on a Cylindrical Elastomeric Membrane

Directory of Open Access Journals (Sweden)

Chi-Chieh Huang

2014-06-01

Full Text Available We present a wide-angle, broad-spectrum cylindrical lens based on reflections from an array of three-dimensional, high-aspect-ratio micro-mirrors fabricated on a cylindrical elastomeric substrate, functionally inspired by natural reflecting superposition compound eyes. Our device can perform one-dimensional focusing and beam-shaping comparable to conventional refraction-based cylindrical lenses, while avoiding chromatic aberration. The focal length of our cylindrical lens is 1.035 mm, suitable for micro-optical systems. Moreover, it demonstrates a wide field of view of 152° without distortion, as well as modest spherical aberrations. Our work could be applied to diverse applications including laser diode collimation, barcode scanning, holography, digital projection display, microlens arrays, and optical microscopy.

Spiral modes in cold cylindrical systems

International Nuclear Information System (INIS)

Robe, H.

1975-01-01

The linearized hydrodynamical equations governing the non-axisymmetric free modes of oscillation of cold cylindrical stellar systems are separated in cylindrical coordinates and solved numerically for two models. Short-wavelength unstable modes corresponding to tight spirals do not exist; but there exists an unstable growing mode which has the form of trailing spirals which are quite open. (orig.) [de

The Newtonian force experienced by a point mass near a finite cylindrical source

International Nuclear Information System (INIS)

Selvaggi, Jerry P; Salon, Sheppard; Chari, M V K

2008-01-01

The Newtonian gravitational force experienced by a point mass located at some external point from a thick-walled, hollow and uniform finite circular cylindrical body was recently solved by Lockerbie, Veryaskin and Xu (1993 Class. Quantum Grav. 10 2419). Their method of attack relied on the introduction of the circular cylindrical free-space Green function representation for the inverse distance which appears in the formulation of the Newtonian potential function. This ultimately leads Lockerbie et al to a final expression for the Newtonian potential function which is expressed as a double summation of even-ordered Legendre polynomials. However, the kernel of the cylindrical free-space Green function which is represented by an infinite integral of the product of two Bessel functions and a decaying exponential can be analytically evaluated in terms of a toroidal function. This leads to a simplification in the mathematical analysis developed by Lockerbie et al. Also, each term in the infinite series solution for the Newtonian potential function can be expressed in closed form in terms of elementary functions. The authors develop the Newtonian potential function by employing toroidal functions of zeroth order or Legendre functions of half-integral degree, Q m-1/2 (β)(Bouwkamp and de Bruijn 1947 J. Appl. Phys.18 562, Cohl et al 2001 Phys. Rev.A 64 052509-1, Selvaggi et al 2004 IEEE Trans. Magn.40 3278). These functions are monotonically decreasing and converge rapidly (Moon and Spencer 1961 Field Theory for Engineers (New Jersey: Van Nostrand Company) pp 368-76, Cohl and Tohline 1999 Astrophys. J.527 86). The introduction of the toroidal harmonic expansion leads to an infinite series solution for which each term can be expressed as an elementary function. This enables one to easily compute the axial and radial forces experienced by an internal or an external point mass

Assessing Reliability of Cold Spray Sputter Targets in Photovoltaic Manufacturing

Science.gov (United States)

Hardikar, Kedar; Vlcek, Johannes; Bheemreddy, Venkata; Juliano, Daniel

2017-10-01

Cold spray has been used to manufacture more than 800 Cu-In-Ga (CIG) sputter targets for deposition of high-efficiency photovoltaic thin films. It is a preferred technique since it enables high deposit purity and transfer of non-equilibrium alloy states to the target material. In this work, an integrated approach to reliability assessment of such targets with deposit weight in excess of 50 lb. is undertaken, involving thermal-mechanical characterization of the material in as-deposited condition, characterization of the interface adhesion on cylindrical substrate in as-deposited condition, and developing means to assess target integrity under thermal-mechanical loads during the physical vapor deposition (PVD) sputtering process. Mechanical characterization of cold spray deposited CIG alloy is accomplished through the use of indentation testing and adaptation of Brazilian disk test. A custom lever test was developed to characterize adhesion along the cylindrical interface between the CIG deposit and cylindrical substrate, overcoming limitations of current standards. A cohesive zone model for crack initiation and propagation at the deposit interface is developed and validated using the lever test and later used to simulate the potential catastrophic target failure in the PVD process. It is shown that this approach enables reliability assessment of sputter targets and improves robustness.

Cylindrical target Li-beam-driven hohlraum experiments

International Nuclear Information System (INIS)

Derzon, M.S.; Aubert, J.; Chandler, G.A.

1998-06-01

The authors performed a series of experiments on the Particle Beam Fusion Accelerator II (PBFA II) in May, 1994, and obtained a brightness temperature of 61 ± 2 eV for an ion-beam heated hohlraum. The hohlraum was a 4-mm-diameter, right-circular cylinder with a 1.5-mm-thick gold wall, a low-density CH foam fill, and a 1.5- or 3-mm-diameter diagnostic aperture in the top. The nominal parameters of the radially-incident PBFA II Li ion beam were 9 MeV peak energy (∼10 MeV at the gas cell) at the target at a peak power of 2.5 ± 0.3 TW/cm 2 and a 15 ns pulse width. Azimuthal variations in intensity of a factor of 3, with respect to the mean, were observed. Nonuniformities in thermal x-ray emission across the area of the diagnostic hole were also observed. Time-dependent hole-closure velocities were measured: the time-averaged velocity of ∼2 cm/micros is in good agreement with sound speed estimates. Unfolded x-ray spectra and brightness temperatures as a function of time are reported and compared to simulations. Hole closure corrections are discussed with comparisons between XRD and bolometer measurements. Temperature scaling with power on target is also presented

Zn Thin Film Deposition for Fe Layer Shielding Use the Sputtering Technique on Cylindrical Form

International Nuclear Information System (INIS)

Yunanto; Tjipto Sujitno, BA; Suprapto; Simbolon, Sahat

2002-01-01

Deposition of thin film on Fe substrate use sputtering technique on cylindrical form was carried out. The purpose of this research is to protect Fe due to the corrosion with Zn thin film. Sputtering method was proposed to protect a component of complex form. Substrate has functioned as anode, meanwhile target in cylindrical form as a cathode. Argon ion from anode bombard Zn with enough energy for releasing Zn. Zn atom would scatter and some of then was focused on the anode. For testing Zn atom on Fe by using XRF and corrosion rate with potentiostat. It was found that corrosion rate was decreased from 0.051 mpy to 0.031 mpy on 0.63 % of Fe substrate. (author)

Parametric Investigation of Miniaturized Cylindrical and Annular Hall Thrusters

International Nuclear Information System (INIS)

Smirnov, A.; Raitses, Y.; Fisch, N.J.

2002-01-01

Conventional annular Hall thrusters become inefficient when scaled to low power. An alternative approach, a 2.6-cm miniaturized cylindrical Hall thruster with a cusp-type magnetic field distribution, was developed and studied. Its performance was compared to that of a conventional annular thruster of the same dimensions. The cylindrical thruster exhibits discharge characteristics similar to those of the annular thruster, but it has a much higher propellant ionization efficiency. Significantly, a large fraction of multi-charged xenon ions might be present in the outgoing ion flux generated by the cylindrical thruster. The operation of the cylindrical thruster is quieter than that of the annular thruster. The characteristic peak in the discharge current fluctuation spectrum at 50-60 kHz appears to be due to ionization instabilities. In the power range 50-300 W, the cylindrical and annular thrusters have comparable efficiencies (15-32%) and thrusts (2.5-12 mN). For the annular configuration, a voltage less than 200 V was not sufficient to sustain the discharge at low propellant flow rates. The cylindrical thruster can operate at voltages lower than 200 V, which suggests that a cylindrical thruster can be designed to operate at even smaller power

Robotic Hand with Flexible Fingers for Grasping Cylindrical Objects

OpenAIRE

柴田, 瑞穂

2015-01-01

In this manuscript, a robotic hand for grasping a cylindrical object is proposed. This robotic hand has flexible fingers that can hold a cylindrical object during moving. We introduce a grasping strategy for a cylindrical object in terms of state transition graph. In this strategy the robotic hand picks up the cylindrical object utilizing a suction device before the hand grasp the object. We also design the flexible fingers; then, we investigate the validity of this robotic hand via several e...

A cylindrical multiwire high-pressure gas proportional chamber surrounding a gaseous $_{2} target with a mylar separation foil $6 \\mu m thick

CERN Document Server

Gastaldi, Ugo; Averdung, H; Bailey, J; Beer, G A; Dreher, B; Erdman, K L; Klempt, E; Merle, K; Neubecker, K; Sabev, C; Schwenk, H; Wendling, R D; White, B L; Wodrich, R

1978-01-01

The characteristics and performances of a cylindrical multiwire proportional chamber built and used at CERN in experiment S142 for the study of the pp atom spectroscopy are presented. The chamber surrounds a high-pressure gaseous H/sub 2/ target, from which it is separated by a very thin window (6 mu m mylar foil). The active volume (90 cm long; 2 cm thick, internal diameter=30 cm) is divided into 36 equal and independent cells each covering 10 degrees in azimuth. At 4 abs. atm the detection efficiency for X-rays is higher than 20% in the whole energy range 1.5-15 keV. Typical resolutions are 35% fwhm for the 3 ke V Ar fluorescence line and 25% fwhm for the 5.5 keV /sup 54/Mn line. Working pressures from 0.5 to 16 abs. atm have been used. (8 refs).

Cylindrical continuous martingales and stochastic integration in infinite dimensions

NARCIS (Netherlands)

Veraar, M.C.; Yaroslavtsev, I.S.

2016-01-01

In this paper we define a new type of quadratic variation for cylindrical continuous local martingales on an infinite dimensional spaces. It is shown that a large class of cylindrical continuous local martingales has such a quadratic variation. For this new class of cylindrical continuous local

Fast calculation method for computer-generated cylindrical holograms.

Science.gov (United States)

Yamaguchi, Takeshi; Fujii, Tomohiko; Yoshikawa, Hiroshi

2008-07-01

Since a general flat hologram has a limited viewable area, we usually cannot see the other side of a reconstructed object. There are some holograms that can solve this problem. A cylindrical hologram is well known to be viewable in 360 deg. Most cylindrical holograms are optical holograms, but there are few reports of computer-generated cylindrical holograms. The lack of computer-generated cylindrical holograms is because the spatial resolution of output devices is not great enough; therefore, we have to make a large hologram or use a small object to fulfill the sampling theorem. In addition, in calculating the large fringe, the calculation amount increases in proportion to the hologram size. Therefore, we propose what we believe to be a new calculation method for fast calculation. Then, we print these fringes with our prototype fringe printer. As a result, we obtain a good reconstructed image from a computer-generated cylindrical hologram.

Refractive index dependent local electric field enhancement in cylindrical gold nanohole

International Nuclear Information System (INIS)

Zhu Jian

2011-01-01

We report on the local electric field characters in a long cylindrical gold nanohole. Theoretical calculation results based on quasi-static model show that the local environmental dielectric constant dependent electric field intensity and field distribution in the gold nanohole show quite unique properties, different from those in the thin gold nanotube. Because of the thick gold wall, no plasmon hybridization exists. So there is only one resonance frequency taking place, and the intense local field has been focused into the gold nanohole. Our main finding is that, the local field in the nanohole is largely dependent on the inner hole refractive index and outer environmental refractive index. The competition between inner hole and outer polarization leads to a non-monotonic change of the local field intensity with increasing the dielectric constant of the nanohole. This refractive index controlled local field enhancement in cylindrical gold nanohole presents a potential for tunable surface-enhanced fluorescence and novel nano-optical biosensing applications.

Read/write performance of perpendicular double-layered cylindrical media

International Nuclear Information System (INIS)

Yamada, H.; Shimatsu, T.; Watanabe, I.; Tsuchiyama, R.; Aoi, H.; Muraoka, H.; Nakamura, Y.

2005-01-01

A cylindrical magnetic storage system using perpendicular double-layered media has been developed. CoCrTa/CoZrNb deposited on a rotating cylindrical substrate shows perpendicular anisotropy and magnetic properties, which have almost the same characteristics as conventional disk-media. The fundamental read/write characteristics of perpendicular double-layered cylindrical media were measured using a single-pole-type (SPT) writer with a sliding-contact-type slider and a merged giant magneto-resistive (GMR) reader with a one-pad-type slider designed for use with cylindrical media. Preliminary studies for improving the characteristics of the recording layer are also described

A model of high-rate indentation of a cylindrical striking pin into a deformable body

Science.gov (United States)

Zalazinskaya, E. A.; Zalazinsky, A. G.

2017-12-01

Mathematical modeling of an impact and high-rate indentation to a significant depth of a flat-faced hard cylindrical striking pin into a massive deformable target body is carried out. With the application of the kinematic extreme theorem of the plasticity theory and the kinetic energy variation theorem, the phase trajectories of the striking pin are calculated, the initial velocity of the striking pin in the body, the limit values of the inlet duct length, and the depth of striking pin penetration into the target are determined.

The decrease of cylindrical pempek quality during boiling

Science.gov (United States)

Karneta, R.; Gultom, N. F.

2017-09-01

The research objective was to study the effects of temperature and formulation on quality of pempek lenjer during boiling. Treatments in this study were four levels of pempek formulation and five levels of temperature. Data was processed by using analysis of variance (Anova). If test results showed that samples were significantly different or highly significantly different, then further test was conducted by using Honestly Significant Different. The results showed that chemical analysis showed that fish dominant formula of cylindrical pempek had higher water content, protein content, lipid content and ash content than that of tapioca starch dominant formula, but it had lower carbohydrate content and fibre content than that of tapioca starch dominant formula.The higher the temperature at center point of cylindrical pempek, the lower the chemical quality of cylindrical pempek. The effect of formula on physical quality of cylindrical pempek showed that tapioca starch dominant formula had more rubbery texture, more neutral pH and brighter color than that of fish dominant formula.The temperature change had no significant effect on texture and pH of cylindrical pempek, but it had significant effect on lightness, intensity and chromatic color especially after exceeding optimum time of boiling.

Cylindrical solitons in shallow water of variable depth

International Nuclear Information System (INIS)

Carbonaro, P.; Floris, R.; Pantano, P.

1983-01-01

The propagation and the interaction of cylindrical solitons in shallow water of variable depth are studied. Starting from the cylindrically symmetric version of the equations describing long waves in a beach, a Korteweg-de Vries equation is derived. Since no exact analytical solution has been found to date for this equation, some remarkable cases in which the equation takes up a tractable form are analyzed. Finally the intercation between cylindrical imploding and expanding waves is considered and the phase shifts caused by the head-on collision are given

Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer

Directory of Open Access Journals (Sweden)

Jie Xu

2017-12-01

Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.

Studies on radiation symmetrization in heavy-ion driven hohlraum targets

International Nuclear Information System (INIS)

Temporal, M.; Atzeni, S.

1993-01-01

Radiation symmetrization within spherical, ellipsoidal and cylindral hohlraum targets for heavy ion inertial confinement fusion (ICF) is studied by means of a 3-D numerical, static model, in which realistic assumptions are made concerning the geometry of the system and, particularly, of the radiation converters. Among the systems so far studied, only spherical hohlraums with six converters achieve the illumination symmetry of the fusion capsule considered necessary for ICF applications. A parametric study of cylindrical hohlraums enlightens the effect of several parameter changes, and suggests directions for further studies, aiming at the design of two-converter targets

Plastic buckling of cylindrical shells

International Nuclear Information System (INIS)

Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

1994-01-01

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

Cylindrical Piezoelectric Fiber Composite Actuators

Science.gov (United States)

Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

2008-01-01

The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

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....

MHD peristaltic transport of spherical and cylindrical magneto-nanoparticles suspended in water

Directory of Open Access Journals (Sweden)

F. M. Abbasi

2015-07-01

Full Text Available Advancements in the biomedical engineering have enhanced the usage of magnto-nanoparticles in improving the precision and efficiency of the magneto-drug delivery systems. Such systems make use of the externally applied magnetic fields to direct the drug towards a specific target in the human body. Peristalsis of magneto-nanofluids is of significant importance in such considerations. Hence peristaltic transport of Fe3O4-water nanofluid through a two-dimensional symmetric channel is analyzed in the presence of an externally applied constant magnetic field. Hamilton-Crosser’s model of the thermal conductivity is utilized in the problem development. The nanofluid saturates a non-uniform porous medium in which the porosity of the porous medium varies with the distance from the channel walls. Analysis is performed for the spherical and the cylindrical nanoparticles. Resulting system of equations is numerically solved. Impacts of sundry parameters on the axial velocity, temperature, pressure gradient and heat transfer rate at the boundary are examined. Comparison between the results for spherical and cylindrical nanoparticles is also presented. Results show that the nanoparticles volume fraction and the Hartman number have increasing effect on the pressure gradient throughout the peristaltic tract. Effective heat transfer rate at the boundary tends to enhance with an increase in the nanoparticles volume fraction. Use of spherical nanoparticles results in a higher value of axial velocity and the temperature at the center of channel when compared with the case of cylindrical nanoparticles.

Coupled dilaton and electromagnetic field in cylindrically symmetric ...

Indian Academy of Sciences (India)

The dilaton black hole solutions have attracted considerable attention for the ... theory and study the corresponding cylindrically symmetric spacetime, where .... where Йm and Йe are integration constants to be interpreted later as the ..... feature is apparent for the cylindrically symmetric spacetime in the presence of the dila-.

MEGAPIE analytical support task : characterization of lead-bismuth eutectic and sodium-cooled tungsten target materials for accelerator driven systems

International Nuclear Information System (INIS)

Gohar, Y.

2002-01-01

Lead-Bismuth Eutectic and Tungsten are under consideration as target materials with high-energy protons for generating neutrons to drive actinide and fission product transmuters. A detailed characterization has been performed to study the performance of these target materials as a function of the main variables and the design selections. The characterization includes the neutron yield, the spatial energy deposition, the neutron spectrum, the beam window performance, and the target buffer impact on the target performance. The characterization has also considered high-energy deuteron particles to study the impact on the target neutronic performance. The obtained results quantify the performance of the Lead-Bismuth Eutectic and Tungsten target materials as a function of the target variables and design selections

Implosion of Cylindrical Cavities via Short Duration Impulsive Loading

Science.gov (United States)

Huneault, Justin; Higgins, Andrew

2014-11-01

An apparatus has been developed to study the collapse of a cylindrical cavity in gelatin subjected to a symmetric impact-driven impulsive loading. A gas-driven annular projectile is accelerated to approximately 50 m/s, at which point it impacts a gelatin casting confined by curved steel surfaces that allow a transition from an annular geometry to a cylindrically imploding motion. The implosion is visualized by a high-speed camera through a window which forms the top confining wall of the implosion cavity. The initial size of the cavity is such that the gelatin wall is two to five times thicker than the impacting projectile. Thus, during impact the compression wave which travels towards the cavity is closely followed by a rarefaction resulting from the free surface reflection of the compression wave in the projectile. As the compression wave in the gelatin reaches the inner surface, it will also reflect as a rarefaction wave. The interaction between the rarefaction waves from the gelatin and projectile free surfaces leads to large tensile stresses resulting in the spallation of a relatively thin shell. The study focuses on the effect of impact parameters on the thickness and uniformity of the imploding shell formed by the cavitation in the imploding gelatin cylinder.

Tearing instability in cylindrical plasma configuration

International Nuclear Information System (INIS)

Zelenyj, L.M.

1979-01-01

The effect of the neutral-layer cylindrical geometry on the development of the tearing instability has been investigated in detail. The increments of the instability for all the regimes have been found. The influence of cylindrical effects becomes manifesting itself at small, as compared to the layer characteristic thickness, distances from the axis, and, finally, the electron regime of the instability development transforms into an ion one. The results obtained are of interest for studying the plasma stability in the devices of the ''Astron'' type and in magnetospheres of cosmic objects

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 magnetostatic interaction energy. For comparison, the forces involved are also calculated numerically using finite elements methods. Based on the conservation of the magnetostatic and kinetic energies, the exit and asymptotic velocities are determined. The derived formulas can be used to optimize the generated...... forces and motion of the inner cylindrical magnet....

A role for fragment-based drug design in developing novel lead compounds for central nervous system targets

Directory of Open Access Journals (Sweden)

Michael J. Wasko

2015-09-01

Full Text Available Hundreds of millions of U.S. dollars are invested in the research and development of a single drug. Lead compound development is an area ripe for new design strategies. Therapeutic lead candidates have been traditionally found using high-throughput in vitro pharmacologic screening, a costly method for assaying thousands of compounds. This approach has recently been augmented by virtual screening, which employs computer models of the target protein to narrow the search for possible leads. A variant of virtual screening is fragment-based drug design, an emerging in silico lead discovery method that introduces low molecular weight fragments, rather than intact compounds, into the binding pocket of the receptor model. These fragments serve as starting points for growing the lead candidate. Current efforts in virtual fragment-based drug design within central nervous system (CNS targets are reviewed, as is a recent rule-based optimization strategy in which new molecules are generated within a 3D receptor binding pocket using the fragment as a scaffold. This process places special emphasis on creating synthesizable molecules but also exposes computational questions worth addressing. Fragment-based methods provide a viable, relatively low-cost alternative for therapeutic lead discovery and optimization that can be applied to CNS targets to augment current design strategies.

A Role for Fragment-Based Drug Design in Developing Novel Lead Compounds for Central Nervous System Targets.

Science.gov (United States)

Wasko, Michael J; Pellegrene, Kendy A; Madura, Jeffry D; Surratt, Christopher K

2015-01-01

Hundreds of millions of U.S. dollars are invested in the research and development of a single drug. Lead compound development is an area ripe for new design strategies. Therapeutic lead candidates have been traditionally found using high-throughput in vitro pharmacological screening, a costly method for assaying thousands of compounds. This approach has recently been augmented by virtual screening (VS), which employs computer models of the target protein to narrow the search for possible leads. A variant of VS is fragment-based drug design (FBDD), an emerging in silico lead discovery method that introduces low-molecular weight fragments, rather than intact compounds, into the binding pocket of the receptor model. These fragments serve as starting points for "growing" the lead candidate. Current efforts in virtual FBDD within central nervous system (CNS) targets are reviewed, as is a recent rule-based optimization strategy in which new molecules are generated within a 3D receptor-binding pocket using the fragment as a scaffold. This process not only places special emphasis on creating synthesizable molecules but also exposes computational questions worth addressing. Fragment-based methods provide a viable, relatively low-cost alternative for therapeutic lead discovery and optimization that can be applied to CNS targets to augment current design strategies.

Cylindrical dust acoustic waves with transverse perturbation

International Nuclear Information System (INIS)

Xue Jukui

2003-01-01

The nonlinear dust acoustic waves in dusty plasmas with the combined effects of bounded cylindrical geometry and the transverse perturbation are studied. Using the perturbation method, a cylindrical Kadomtsev-Petviashvili (CKP) equation that describes the dust acoustic waves is deduced for the first time. A particular solution of this CKP equation is also obtained. It is shown that the dust acoustic solitary waves can exist in the CKP equation

A robust approach for analysing dispersion of elastic waves in an orthotropic cylindrical shell

Science.gov (United States)

Kaplunov, J.; Nobili, A.

2017-08-01

Dispersion of elastic waves in a thin orthotropic cylindrical shell is considered, within the framework of classical 2D Kirchhoff-Love theory. In contrast to direct multi-parametric analysis of the lowest propagating modes, an alternative robust approach is proposed that simply requires evaluation of the evanescent modes (quasi-static edge effect), which, at leading order, do not depend on vibration frequency. A shortened dispersion relation for the propagating modes is then derived by polynomial division and its accuracy is numerically tested against the full Kirchhoff-Love dispersion relation. It is shown that the same shortened relation may be also obtained from a refined dynamic version of the semi-membrane theory for cylindrical shells. The presented results may be relevant for modelling various types of nanotubes which, according to the latest experimental findings, possess strong material anisotropy.

Stable pseudoanalytical computation of electromagnetic fields from arbitrarily-oriented dipoles in cylindrically stratified media

Science.gov (United States)

Moon, Haksu; Teixeira, Fernando L.; Donderici, Burkay

2014-09-01

Computation of electromagnetic fields due to point sources (Hertzian dipoles) in cylindrically stratified media is a classical problem for which analytical expressions of the associated tensor Green's function have been long known. However, under finite-precision arithmetic, direct numerical computations based on the application of such analytical (canonical) expressions invariably lead to underflow and overflow problems related to the poor scaling of the eigenfunctions (cylindrical Bessel and Hankel functions) for extreme arguments and/or high-order, as well as convergence problems related to the numerical integration over the spectral wavenumber and to the truncation of the infinite series over the azimuth mode number. These problems are exacerbated when a disparate range of values is to be considered for the layers' thicknesses and material properties (resistivities, permittivities, and permeabilities), the transverse and longitudinal distances between source and observation points, as well as the source frequency. To overcome these challenges in a systematic fashion, we introduce herein different sets of range-conditioned, modified cylindrical functions (in lieu of standard cylindrical eigenfunctions), each associated with nonoverlapped subdomains of (numerical) evaluation to allow for stable computations under any range of physical parameters. In addition, adaptively-chosen integration contours are employed in the complex spectral wavenumber plane to ensure convergent numerical integration in all cases. We illustrate the application of the algorithm to problems of geophysical interest involving layer resistivities ranging from 1000 Ω m to 10-8 Ω m, frequencies of operation ranging from 10 MHz down to the low magnetotelluric range of 0.01 Hz, and for various combinations of layer thicknesses.

Radon progeny distribution in cylindrical diffusion chambers

International Nuclear Information System (INIS)

Pressyanov, Dobromir S.

2008-01-01

An algorithm to model the diffusion of radioactive decay chain atoms is presented. Exact mathematical solutions in cylindrical geometry are given. They are used to obtain expressions for the concentrations of 222 Rn progeny atoms in the volume and deposited on the wall surface in cylindrical diffusion chambers. The dependence of volume fractions of 222 Rn progeny and chamber sensitivity on the coefficient of diffusion of 222 Rn progeny atoms in air is modeled.

Cylindrical geometry for proportional and drift chambers

International Nuclear Information System (INIS)

Sadoulet, B.

1975-06-01

For experiments performed around storage rings such as e + e - rings or the ISR pp rings, cylindrical wire chambers are very attractive. They surround the beam pipe completely without any dead region in the azimuth, and fit well with the geometry of events where particles are more or less spherically produced. Unfortunately, cylindrical proportional or drift chambers are difficult to make. Problems are discussed and two approaches to fabricating the cathodes are discussed. (WHK)

Thermal therapy for breast tumors by using a cylindrical ultrasound phased array with multifocus pattern scanning: a preliminary numerical study

International Nuclear Information System (INIS)

Ho, C-S; Ju, K-C; Cheng, T-Y; Chen, Y-Y; Lin, W-L

2007-01-01

The purpose of this study is to investigate the feasibility of using a 1 MHz cylindrical ultrasound phased array with multifocus pattern scanning to produce uniform heating for breast tumor thermal therapy. The breast was submerged in water and surrounded by the cylindrical ultrasound phased array. A multifocus pattern was generated and electrically scanned by the phased array to enlarge the treatment lesion in single heating. To prevent overheating normal tissues, a large planning target volume (PTV) would be divided into several planes with several subunits on each plane and sequentially treated with a cooling phase between two successive heatings of the subunit. Heating results for different target temperatures (T tgt ), blood perfusion rates and sizes of the PTV have been studied. Furthermore, a superficial breast tumor with different water temperatures was also studied. Results indicated that a higher target temperature would produce a slightly larger thermal lesion, and a higher blood perfusion rate would not affect the heating lesion size but increase the heating time significantly. The acoustic power deposition and temperature elevations in ribs can be minimized by orienting the acoustic beam from the ultrasound phased array approximately parallel to the ribs. In addition, a large acoustic window on the convex-shaped breast surface for the proposed ultrasound phased array and the cooling effect of water would prevent the skin overheating for the production of a lesion at any desired location. This study demonstrated that the proposed cylindrical ultrasound phased array can provide effective heating for breast tumor thermal therapy without overheating the skin and ribs within a reasonable treatment time

Compression of magnetized target in the magneto-inertial fusion

Science.gov (United States)

Kuzenov, V. V.

2017-12-01

This paper presents a mathematical model, numerical method and results of the computer analysis of the compression process and the energy transfer in the target plasma, used in magneto-inertial fusion. The computer simulation of the compression process of magnetized cylindrical target by high-power laser pulse is presented.

A Clustering Method for Data in Cylindrical Coordinates

Directory of Open Access Journals (Sweden)

Kazuhisa Fujita

2017-01-01

Full Text Available We propose a new clustering method for data in cylindrical coordinates based on the k-means. The goal of the k-means family is to maximize an optimization function, which requires a similarity. Thus, we need a new similarity to obtain the new clustering method for data in cylindrical coordinates. In this study, we first derive a new similarity for the new clustering method by assuming a particular probabilistic model. A data point in cylindrical coordinates has radius, azimuth, and height. We assume that the azimuth is sampled from a von Mises distribution and the radius and the height are independently generated from isotropic Gaussian distributions. We derive the new similarity from the log likelihood of the assumed probability distribution. Our experiments demonstrate that the proposed method using the new similarity can appropriately partition synthetic data defined in cylindrical coordinates. Furthermore, we apply the proposed method to color image quantization and show that the methods successfully quantize a color image with respect to the hue element.

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.

Omni Directional Multimaterial Soft Cylindrical Actuator and Its Application as a Steerable Catheter.

Science.gov (United States)

Gul, Jahan Zeb; Yang, Young Jin; Su, Kim Young; Choi, Kyung Hyun

2017-09-01

Soft actuators with complex range of motion lead to strong interest in applying devices like biomedical catheters and steerable soft pipe inspectors. To facilitate the use of soft actuators in devices where controlled, complex, precise, and fast motion is required, a structurally controlled Omni directional soft cylindrical actuator is fabricated in a modular way using multilayer composite of polylactic acid based conductive Graphene, shape memory polymer, shape memory alloy, and polyurethane. Multiple fabrication techniques are discussed step by step that mainly include fused deposition modeling based 3D printing, dip coating, and UV curing. A mathematical control model is used to generate patterned electrical signals for the Omni directional deformations. Characterizations like structural control, bending, recovery, path, and thermal effect are carried out with and without load (10 g) to verify the new cylindrical design concept. Finally, the application of Omni directional actuator as a steerable catheter is explored by fabricating a scaled version of carotid artery through 3D printing using a semitransparent material.

Neutron production in lead targets by high-energy light-mass heavy ions

International Nuclear Information System (INIS)

Daniehl', A.V.; Lyapin, V.S.; Tsvetkov, I.O.

1992-01-01

The characteristics of the time-of-flight spectrometer and the double different distributions of neutrons and secondary charged particles produced by 2 GeV protons and 1 GeVXA d,α, 6 Li and 12 C ions bombarding lead targets are described. Experimental data are compared with the results of calculations by codes SITHA. 17 refs.; 10 figs.; 1 tab

Elemental Technologies for Lead-Bismuth Spallation Target System in J-PARC

International Nuclear Information System (INIS)

Obayashi, H.; Yamaguchi, K.; Saito, S.; Sugawara, T.; Takei, H.; Sasa, T.

2015-01-01

Japan Atomic Energy Agency (JAEA) has been researching and developing an Accelerator-Driven System (ADS) as a dedicated system for the transmutation of long-lived radioactive nuclides. The ADS proposed by JAEA uses the lead-bismuth eutectic (LBE) alloy as a spallation target material and a coolant. In the various R and D for ADS, construction of the Transmutation Experimental Facility (TEF) is planned under the framework of the J-PARC project as a preceding step before the construction of demonstrative ADS. In this R and D, TEF is considered for the experimental investigation of the feasibility of the beam window, the structural materials, and to investigate the operation properties of the target system by using 400 MeV-250 kW proton beam. This target system is consisted of various elements and must be able to operate without troubles during an operation period of TEF facility. Furthermore, in the maintenance period after the operation, because the inside of a hot cell storing a target is exposed to strong radiations, all elements must be designed as remote control devices. In this study, the present conditions of the design and the result of performance test of each important elements were confirmed in the realisation of the LBE target system, such as the monitoring system of flow rate by using the ultrasonic method, the heater system with the metallic heat insulator joined to a flow channel of LBE, and the operability of remote handing. (authors)

Low-energy impact of adaptive cylindrical piezoelectric-composite shells

Energy Technology Data Exchange (ETDEWEB)

Saravanos, D.A. [University of Patras (United Kingdom). Dept. of Mechanical Engineering and Aeronautics; Christoforou, A.P. [Kuwait Univ. (Kuwait). Dept. of Mechanical Engineering

2002-04-01

A theoretical framework for analyzing low-energy impacts of laminated shells with active and sensory piezoelectric layers is presented, including impactor dynamics and contact law. The formulation encompasses a coupled piezoelectric shell theory mixing first order shear displacement assumptions and layerwise variation of electric potential. An exact in-plane Ritz solution for the impact of open cylindrical piezoelectric-composite shells is developed and solved numerically using an explicit time integration scheme. The active impact control problem of adaptive cylindrical shells with distributed curved piezoelectric actuators is addressed. The cases of optimized state feedback controllers and output feedback controllers using piezoelectric sensors are analyzed. Numerical results quantify the impact response of cylindrical shells of various curvatures including the signal of curved piezoelectric sensors. Additional numerical studies quantify the impact response of adaptive cylindrical panels and investigate the feasibility of actively reducing the impact force. (author)

Note: Electrochemical etching of cylindrical nanoprobes using a vibrating electrolyte

International Nuclear Information System (INIS)

Wang, Yufeng; Zeng, Yongbin; Qu, Ningsong; Zhu, Di

2015-01-01

An electrochemical etching process using a vibrating electrolyte of potassium hydroxide to prepare tungsten cylindrical nanotips is developed. The vibrating electrolyte eases the effects of a diffusion layer and extends the etching area, which aid in the production of cylindrical nanotips. Larger amplitudes and a vibration frequency of 35 Hz are recommended for producing cylindrical nanotips. Nanotips with a tip radius of approximately 43 nm and a conical angle of arctan 0.0216 are obtained

Scheduling rules to achieve lead-time targets in outpatient appointment systems

OpenAIRE

Sivakumar, Appa Iyer; Nguyen, Thu Ba Thi; Graves, Stephen C

2015-01-01

This paper considers how to schedule appointments for outpatients, for a clinic that is subject to appointment lead-time targets for both new and returning patients. We develop heuristic rules, which are the exact and relaxed appointment scheduling rules, to schedule each new patient appointment (only) in light of uncertainty about future arrivals. The scheduling rules entail two decisions. First, the rules need to determine whether or not a patient's request can be accepted; then, if the req...

Far-field potentials in cylindrical and rectangular volume conductors.

Science.gov (United States)

Dumitru, D; King, J C; Rogers, W E

1993-07-01

The occurrence of a transient dipole is one method of producing a far-field potential. This investigation qualitatively defines the characteristics of the near-field and far-field electrical potentials produced by a transient dipole in both cylindrical and rectangular volume conductors. Most body segments of electrophysiologic interest such as arms, legs, thorax, and neck are roughly cylindrical in shape. A centrally located dipole generator produces a nonzero equipotential region which is found to occur along the cylindrical wall at a distance from the dipole of approximately 1.4 times the cylinder's radius and 1.9 times the cylinder's radius for the center of the cylinder. This distance to the equi-potential zone along the surface wall expands but remains less than 3.0 times the cylindrical radius when the dipole is eccentrically placed. The magnitude of the equipotential region resulting from an asymmetrically placed dipole remains identical to that when the dipole is centrally located. This behavior is found to be very similar in rectangular shallow conducting volumes that model a longitudinal slice of the cylinder, thus allowing a simple experimental model of the cylinder to be utilized. Amplitudes of the equipotential region are inversely proportional to the cylindrical or rectangular volume's cross-sectional area at the location of dipolar imbalance. This study predicts that referential electrode montages, when placed at 3.0 times the radius or greater from a dipolar axially aligned far-field generator in cylindrical homogeneous volume conductors, will record only equipotential far-field effects.

Effect of cylindrical confinement on the determination of laminar flame speeds using outwardly propagating flames

Energy Technology Data Exchange (ETDEWEB)

Burke, Michael P.; Chen, Zheng; Ju, Yiguang; Dryer, Frederick L. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2009-04-15

The effect of nonspherical (i.e. cylindrical) bomb geometry on the evolution of outwardly propagating flames and the determination of laminar flame speeds using the conventional constant-pressure technique is investigated experimentally and theoretically. The cylindrical chamber boundary modifies the propagation rate through the interaction of the wall with the flow induced by thermal expansion across the flame (even with constant pressure), which leads to significant distortion of the flame surface for large flame radii. These departures from the unconfined case, especially the resulting nonzero burned gas velocities, can lead to significant errors in flame speeds calculated using the conventional assumptions, especially for large flame radii. For example, at a flame radius of 0.5 times the wall radius, the flame speed calculated neglecting confinement effects can be low by {proportional_to}15% (even with constant pressure). A methodology to estimate the effect of nonzero burned gas velocities on the measured flame speed in cylindrical chambers is presented. Modeling and experiments indicate that the effect of confinement can be neglected for flame radii less than 0.3 times the wall radius while still achieving acceptable accuracy (within 3%). The methodology is applied to correct the flame speed for nonzero burned gas speeds, in order to extend the range of flame radii useful for flame speed measurements. Under the proposed scaling, the burned gas speed can be well approximated as a function of only flame radius for a given chamber geometry - i.e. the correction function need only be determined once for an apparatus and then it can be used for any mixture. Results indicate that the flow correction can be used to extract flame speeds for flame radii up to 0.5 times the wall radius with somewhat larger, yet still acceptable uncertainties for the cases studied. Flow-corrected burning velocities are measured for hydrogen and syngas mixtures at atmospheric and

Proton-beam window design for a transmutation facility operating with a liquid lead target

Energy Technology Data Exchange (ETDEWEB)

Jansen, C.; Lypsch, F.; Lizana, P. [Institute for Safety Research and Reactor Technology, Juelich (Germany)] [and others

1995-10-01

The proton beam target of an accelerator-driven transmutation facility can be designed as a vertical liquid lead column. To prevent lead vapor from entering the accelerator vacuum, a proton-beam window has to separate the area above the lead surface from the accelerator tube. Two radiation-cooled design alternatives have been investigated which should withstand a proton beam of 1.6 GeV and 25 mA. Temperature calculations based on energy deposition calculations with the Monte Carlo code HETC, stability analysis and spallation-induced damage calculations have been performed showing the applicability of both designs.

Sensitivity optimization in whispering gallery mode optical cylindrical biosensors

Science.gov (United States)

Khozeymeh, F.; Razaghi, M.

2018-01-01

Whispering-gallery-mode resonances propagated in cylindrical resonators have two angular and radial orders of l and i. In this work, the higher radial order whispering-gallery-mode resonances, (i = 1 - 4), at a fixed l are examined. The sensitivity of theses resonances is analysed as a function of the structural parameters of the cylindrical resonator like different radii and refractive index of composed material of the resonator. A practical application where cylindrical resonators are used for the measurement of glucose concentration in water is presented as a biosensor demonstrator. We calculate the wavelength shifts of the WG1-4, in several glucose/water solutions, with concentrations spanning from 0.0% to 9.0.% (weight/weight). Improved sensitivity can be achieved using multi-WGM cylindrical resonators with radius of R = 100 μm and resonator composed material of MgF 2 with refractive index of nc = 1.38. Also the effect of polarization on sensitivity is considered for all four WGMs. The best sensitivity of 83.07 nm/RIU for the fourth WGM with transverse magnetic polarization, is reported. These results propose optimized parameters aimed to fast designing of cylindrical resonators as optical biosensors, where both the sensitivity and the geometries can be optimized.

Neutron yield from thick lead target by the action of high-energy electrons

International Nuclear Information System (INIS)

Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.; Sorokin, P.V.

1978-01-01

The results are presented of studying the complete neutron yield from a lead target bombarded by high-energy electrons. Neutrons were recorded by the method of radio-active indicators. The dependence of the neutron yield on the target thickness varying from 0.2 to 8 cm was obtained at the energies of electrons of 230 and 1200 MeV. The neutron yield for the given energies with the target of 6 cm in thickness is in the range of saturation and is 0.1 +-0.03 and 0.65+-0.22 (neutr./MeV.el.), respectively. The neutron angular distributions were measured for different thicknesses of targets at the 201, 230 and 1200 MeV electrons. Within the error limits the angular distributions are isotropic. The dependence of neutron yield on the electron energy was examined for a 3 cm thick target. In the energy range of 100-1200 MeV these values are related by a linear dependence with the proportionality coefficient C=3x10 -4 (neutr./MeV.el.)

Cylindrical and spherical dust-acoustic wave modulations in dusty ...

Indian Academy of Sciences (India)

Abstract. The nonlinear wave modulation of planar and non-planar (cylindrical and spherical) dust-acoustic waves (DAW) propagating in dusty plasmas, in the presence of non-extensive distribu- tions for ions and electrons is investigated. By employing multiple scales technique, a cylindrically and spherically modified ...

Settling of a cylindrical particle in a stagnant fluid

DEFF Research Database (Denmark)

Sørensen, Henrik; Rosendahl, Lasse; Yin, Chungen

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 mo...

Power deposition in a cylindrical geometry using B-10 coatings

International Nuclear Information System (INIS)

Chung, A.K.; Prelas, M.A.

1983-01-01

The transport of charged particles produced by 10 B (n, α) Li and 235 U (n, νn) ff nuclear reactions in a two region cylindrical geometry is predicted. We employed a mean-range straight-flight approximation to calculate the power deposition by the charged particles in a gaseous medium. Our model demonstrated some features in a cylindrical experiment which were suspected but not proven. In the common slab model used by Guyot et al 1 and Romero 2 , the spatial distribution of power deposition is much flatter than it would be in a cylindrical model. A steeper gradient in the power deposition is expected in a cylindrical geometry than in a slab geometry. We also found that for a standard thickness of Boron-10 coating (1.73 μm) used in NPLs, the expected efficiency of a cylindrical geometry (7.5%) is much lower than the 12% efficiency predicted by the slab model. Indeed the use of slab geometry in modeling current NPL experimental devices is not accurate

Tight multilattices calculated by extended-cell cylindrization

Energy Technology Data Exchange (ETDEWEB)

Segev, M; Carmona, S

1983-01-01

Among the common features of advanced LWR concepts are the tightness of lattices and the symbiotic setting of different fuels. Such symbioses often come in the form of multilattices, whose numerically-repeated unit is a configuration of several pins, typically with one pin type at the center and pins of a second type surrounding the center pin. If this extended-cell (EC) unit is cylindricized, then a simple transport calculation of the unit will be possible. If the lattice of such units is tight, there is further an a priori reason to expect the cylindrization to introduce only a small distortion of the true neutron fluxes in the lattice. A strict numerical validation of the EC cylindrization approximation is impractical, but similar validations can be carried out for regular lattices, viewed as being made up of multicell units whose centers are moderators and whose peripheries are fuel pins. In these comparisons the EC cylindrization approximation gives good results.

Scattering of spermatozoa off cylindrical pillars

Science.gov (United States)

Bukatin, Anton; Lushi, Enkeleida; Kantsler, Vasily

2017-11-01

The motion of micro-swimmers in structured environments, even though crucial in processes such as in vivo and in vitro egg fertilization, is still not completely understood. We combine microfluidic experiments with mathematical modeling of 3D swimming near convex surfaces to quantify the dynamics of individual sperm cells in the proximity of cylindrical pillars. Our results show that the hydrodynamic and contact forces that account for the shape asymmetry and flagellar motion, are crucial in correctly describing the dynamics observed in the experiments. Last, we discuss how the size of the cylindrical obstacles determines whether the swimmers scatter off or get trapped circling the pillar.

Free Vibration Characteristics of Cylindrical Shells Using a Wave Propagation Method

Directory of Open Access Journals (Sweden)

A. Ghoshal

2001-01-01

Full Text Available In the present paper, concept of a periodic structure is used to study the characteristics of the natural frequencies of a complete unstiffened cylindrical shell. A segment of the shell between two consecutive nodal points is chosen to be a periodic structural element. The present effort is to modify Mead and Bardell's approach to study the free vibration characteristics of unstiffened cylindrical shell. The Love-Timoshenko formulation for the strain energy is used in conjunction with Hamilton's principle to compute the natural propagation constants for two shell geometries and different circumferential nodal patterns employing Floquet's principle. The natural frequencies were obtained using Sengupta's method and were compared with those obtained from classical Arnold-Warburton's method. The results from the wave propagation method were found to compare identically with the classical methods, since both the methods lead to the exact solution of the same problem. Thus consideration of the shell segment between two consecutive nodal points as a periodic structure is validated. The variations of the phase constants at the lower bounding frequency for the first propagation band for different nodal patterns have been computed. The method is highly computationally efficient.

A cylindrical drift chamber for radiative muon capture experiments at TRIUMF

International Nuclear Information System (INIS)

Henderson, R.S.; Dawson, R.J.; Azuelos, G.; Robertson, B.C.; Hasinoff, M.D.; Ahamad, S.; Gorringe, T.P.; Serna-Angel, A.; Blecher, M.; Wright, D.H.

1990-01-01

In the Standard Model, the weak interaction is purely V-A in character. However in semileptonic reactions the strong force induces additional couplings. Radiative muon capture (RMC), μ - Z → ν(Z-1)γ, is a process which is particularly sensitive to the induced pseudoscalar coupling constant, g p , which is still very poorly determined experimentally. Due to the extremely small branching ratio (∼ 6 x 10 -8 ), the elementary reaction μ - p → νnγ has never been measured. Effort to date has concentrated on nuclear RMC where the branching ratio is much larger, but the interpretation of these results is hindered by nuclear structure uncertainties. A measurement is being carried out at TRIUMF to determine the rate of RMC on hydrogen to a precision of 8% leading to a determination of g p with an error of 10%. The detection system is based on a large volume cylindrical drift chamber, in an axial magnetic field, acting as an e + e - pair spectrometer with a solid angle of ≅ 2 π. The design, construction and performance of the cylindrical drift chamber are discussed

Scale interaction and arrangement in a turbulent boundary layer perturbed by a wall-mounted cylindrical element

Science.gov (United States)

Tang, Zhanqi; Jiang, Nan

2018-05-01

This study reports the modifications of scale interaction and arrangement in a turbulent boundary layer perturbed by a wall-mounted circular cylinder. Hot-wire measurements were executed at multiple streamwise and wall-normal wise locations downstream of the cylindrical element. The streamwise fluctuating signals were decomposed into large-, small-, and dissipative-scale signatures by corresponding cutoff filters. The scale interaction under the cylindrical perturbation was elaborated by comparing the small- and dissipative-scale amplitude/frequency modulation effects downstream of the cylinder element with the results observed in the unperturbed case. It was obtained that the large-scale fluctuations perform a stronger amplitude modulation on both the small and dissipative scales in the near-wall region. At the wall-normal positions of the cylinder height, the small-scale amplitude modulation coefficients are redistributed by the cylinder wake. The similar observation was noted in small-scale frequency modulation; however, the dissipative-scale frequency modulation seems to be independent of the cylindrical perturbation. The phase-relationship observation indicated that the cylindrical perturbation shortens the time shifts between both the small- and dissipative-scale variations (amplitude and frequency) and large-scale fluctuations. Then, the integral time scale dependence of the phase-relationship between the small/dissipative scales and large scales was also discussed. Furthermore, the discrepancy of small- and dissipative-scale time shifts relative to the large-scale motions was examined, which indicates that the small-scale amplitude/frequency leads the dissipative scales.

Two-dimensional collapse calculations of cylindrical clouds

International Nuclear Information System (INIS)

Bastien, P.; Mitalas, R.

1979-01-01

A two-dimensional hydrodynamic computer code has been extensively modified and expanded to study the collapse of non-rotating interstellar clouds. The physics and the numerical methods involved are discussed. The results are presented and discussed in terms of the Jeans number. The critical Jeans number for collapse of non-rotating cylindrical clouds whose length is the same as their diameter is 1.00. No evidence for fragmentation has been found for these clouds, but fragmentation seems quite likely for more elongated cylindrical clouds. (author)

Rotation, inversion and perversion in anisotropic elastic cylindrical tubes and membranes

KAUST Repository

Goriely, A.

2013-03-06

Cylindrical tubes and membranes are universal structural elements found in biology and engineering over a wide range of scales.Working in the framework of nonlinear elasticity, we consider the possible deformations of elastic cylindrical shells reinforced by one or two families of fibres. We consider both small and large deformations and the reduction from thick cylindrical shells (tubes) to thin shells (cylindrical membranes). In particular, a number of universal parameter regimes can be identified where the response behaviour of the cylinder is qualitatively different. This include the possibility of inversion of twist or axial strain when the cylinder is subject to internal pressure. Copyright © The Royal Society 2013.

Axially symmetrical stresses measurement in the cylindrical tube using DIC with hole-drilling

Science.gov (United States)

Ma, Yinji; Yao, Xuefeng; Zhang, Danwen

2015-03-01

In this paper, a new method combining the digital image correlation (DIC) with the hole-drilling technology to characterize the axially symmetrical stresses of the cylindrical tube is developed. First, the theoretical expressions of the axially symmetrical stresses in the cylindrical tube are derived based on the displacement or strain fields before and after hole-drilling. Second, the release of the axially symmetrical stresses for the cylindrical tube caused by hole-drilling is simulated by the finite element method (FEM), which indicates that the axially symmetrical stresses of the cylindrical tube calculated by the cylindrical solution is more accuracy than that for traditionally planar solution. Finally, both the speckle image information and the displacement field of the cylindrical tube before and after hole-drilling are extracted by combining the DIC with the hole-drilling technology, then the axially symmetrical loading induced stresses of the cylindrical tube are obtained, which agree well with the results from the strain gauge method.

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.

Antibubbles and fine cylindrical sheets of air

KAUST Repository

Beilharz, D.; Guyon, A.; Li, E.  Q.; Thoraval, M.-J.; Thoroddsen, Sigurdur T

2015-01-01

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.

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags.

Science.gov (United States)

Bruton, Jared T; Nelson, Todd G; Zimmerman, Trent K; Fernelius, Janette D; Magleby, Spencer P; Howell, Larry L

2016-09-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the 'flasher' and the 'inverted-cone fold', for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver's side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes.

Cylindrical pressure vessel constructed of several layers

International Nuclear Information System (INIS)

Yamauchi, Takeshi.

1976-01-01

For a cylindrical pressure vessel constructed of several layers whose jacket has at least one circumferential weld joining the individual layers, it is proposed to provide this at least at the first bending line turning point (counting from the weld between the jacket and vessel floor), which the sinusoidally shaped jacket has. The section of the jacket extending in between should be made as a full wall section. The proposal is based on calculations of the bending stiffness of cylindrical jackets, which could not yet be confirmed for jackets having several layers. (UWI) [de

Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV

International Nuclear Information System (INIS)

Tall, Y.

2008-03-01

The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

40 CFR 745.226 - Certification of individuals and firms engaged in lead-based paint activities: target housing and...

Science.gov (United States)

2010-07-01

... of experience in a related field (e.g., lead, asbestos, environmental remediation work, or... at least 3 years of experience in a related field (e.g., lead, asbestos, environmental remediation... engaged in lead-based paint activities: target housing and child-occupied facilities. 745.226 Section 745...

Analysis of a cylindrical imploding shock wave

International Nuclear Information System (INIS)

Mishkin, E.A.; Fujimoto, Y.

1978-01-01

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 U 1 (xi) → U 1 = 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)

Local field in LiD polarized target material

CERN Document Server

Kisselev, Yu V; Baum, G; Berglund, P; Doshita, N; Gautheron, F; Görtz, S; Horikawa, N; Koivuniemi, J H; Kondo, K; Magnon, A; Meyer, Werner T; Reicherz, G

2004-01-01

We have experimentally studied the first and the second moments of D, **6Li and **7Li (I greater than 1/2) NMR lines in a granulated LiD- target material as a function of nuclear polarizations and the data has been compared with a theory elaborated by Abragam, Roinel and Bouffard for monocrystalline samples. The experiments were carried out in the large COMPASS twin-target at CERN. The static local magnetic field of the polarized nuclei was measured by frequency shift between the NMR-signals in the two oppositely polarized cells and lead to the first moment, whereas the investigation of the second moment was done through Gaussian approximation. The average field magnitude in granulated material was estimated 20% larger than the value given by the calculations for monocrystalline samples of cylindrical shape. The second moment shows a qualitative agreement with the theory but it is slightly larger at the negative than at the positive polarization. In a polarized mode, the moments depend on the saturated microw...

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.

Novel spherical hohlraum with cylindrical laser entrance holes and shields

International Nuclear Information System (INIS)

Lan, Ke; Zheng, Wudi

2014-01-01

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

Cylindrical optical resonators: fundamental properties and bio-sensing characteristics

Science.gov (United States)

Khozeymeh, Foroogh; Razaghi, Mohammad

2018-04-01

In this paper, detailed theoretical analysis of cylindrical resonators is demonstrated. As illustrated, these kinds of resonators can be used as optical bio-sensing devices. The proposed structure is analyzed using an analytical method based on Lam's approximation. This method is systematic and has simplified the tedious process of whispering-gallery mode (WGM) wavelength analysis in optical cylindrical biosensors. By this method, analysis of higher radial orders of high angular momentum WGMs has been possible. Using closed-form analytical equations, resonance wavelengths of higher radial and angular order WGMs of TE and TM polarization waves are calculated. It is shown that high angular momentum WGMs are more appropriate for bio-sensing applications. Some of the calculations are done using a numerical non-linear Newton method. A perfect match of 99.84% between the analytical and the numerical methods has been achieved. In order to verify the validity of the calculations, Meep simulations based on the finite difference time domain (FDTD) method are performed. In this case, a match of 96.70% between the analytical and FDTD results has been obtained. The analytical predictions are in good agreement with other experimental work (99.99% match). These results validate the proposed analytical modelling for the fast design of optical cylindrical biosensors. It is shown that by extending the proposed two-layer resonator structure analyzing scheme, it is possible to study a three-layer cylindrical resonator structure as well. Moreover, by this method, fast sensitivity optimization in cylindrical resonator-based biosensors has been possible. Sensitivity of the WGM resonances is analyzed as a function of the structural parameters of the cylindrical resonators. Based on the results, fourth radial order WGMs, with a resonator radius of 50 μm, display the most bulk refractive index sensitivity of 41.50 (nm/RIU).

Analysis of radial vibrations of poroelastic circular cylindrical shells ...

African Journals Online (AJOL)

DR OKE

vanished, the considered problem reduces to the problem of radial vibrations of fluid-filled poroelastic circular cylindrical shell. (2). When the .... the volume change of the solid to that of liquid. ..... When the outer fluid density is zero, that is, ρof = 0 then the poroelastic cylindrical shell immersed in an acoustic medium will.

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.

Dynamic strength of cylindrical fiber-glass shells and basalt plastic shells under multiple explosive loading

Science.gov (United States)

Syrunin, M. A.; Fedorenko, A. G.

2006-08-01

We have shown experimentally that, for cylindrical shells made of oriented fiberglass platic and basalt plastic there exists a critical level of deformations, at which a structure sustains a given number of explosions from the inside. The magnitude of critical deformation for cylindrical fiberglass shells depends linearly on the logarithm of the number of loads that cause failure. For a given type of fiberglass, there is a limiting level of explosive action, at which the number of loads that do not lead to failure can be sufficiently large (more than ˜ 102). This level is attained under loads, which are an order of magnitude lower than the limiting loads under a single explosive action. Basalt plastic shells can be repeatedly used even at the loads, which cause deformation by ˜ 30-50% lower than the safe value ˜ 3.3.5% at single loading.

On geometry-dependent vortex stability and topological spin excitations on curved surfaces with cylindrical symmetry

International Nuclear Information System (INIS)

Carvalho-Santos, V.L.; Apolonio, F.A.; Oliveira-Neto, N.M.

2013-01-01

We study the Heisenberg model on cylindrically symmetric curved surfaces. Two kinds of excitations are considered. The first is given by the isotropic regime, yielding the sine-Gordon equation and π solitons are predicted. The second one is given by the XY model, leading to a vortex turning around the surface. Helical states are also considered, however, topological arguments cannot be used to ensure its stability. The energy and the anisotropy parameter which stabilizes the vortex state are explicitly calculated for two surfaces: catenoid and hyperboloid. The results show that the anisotropy and the vortex energy depends on the underlying geometry. -- Highlights: •Applying the anisotropic Heisenberg model on curved surfaces. •Appearance of topological solitons on curved surfaces with cylindrical symmetry. •Calculus of the vortex energy, which depends on curvature. •Discussion on features of non-topological helical-like states. •Vortex stability ensured by the anisotropy parameter value

Laminar forced convection in a cylindrical collinear ohmic sterilizer

Directory of Open Access Journals (Sweden)

Pesso Tommaso

2017-01-01

Full Text Available The present work deals with a thermo-fluid analysis of a collinear cylindrical ohmic heater in laminar flow. The geometry of interest is a circular electrically insulated glass pipe with two electrodes at the pipe ends. For this application, since the electrical conductivity of a liquid food depends strongly on the temperature, the thermal analysis of an ohmic heater requires the simultaneous solution of the electric and thermal fields. In the present work the analysis involves decoupling the previous fields by means of an iterative procedure. The thermal field has been calculated using an analytical solution, which leads to fast calculations for the temperature distribution in the heater. Some considerations of practical interest for the design are also given.

Intrinsic cylindrical and spherical waves

International Nuclear Information System (INIS)

Ludlow, I K

2008-01-01

Intrinsic waveforms associated with cylindrical and spherical Bessel functions are obtained by eliminating the factors responsible for the inverse radius and inverse square radius laws of wave power per unit area of wavefront. The resulting expressions are Riccati-Bessel functions for both cases and these can be written in terms of amplitude and phase functions of order v and wave variable z. When z is real, it is shown that a spatial phase angle of the intrinsic wave can be defined and this, together with its amplitude function, is systematically investigated for a range of fixed orders and varying z. The derivatives of Riccati-Bessel functions are also examined. All the component functions exhibit different behaviour in the near field depending on the order being less than, equal to or greater than 1/2. Plots of the phase angle can be used to display the locations of the zeros of the general Riccati-Bessel functions and lead to new relations concerning the ordering of the real zeros of Bessel functions and the occurrence of multiple zeros when the argument of the Bessel function is fixed

Dismantling OPAL's cylindrical magnet core

CERN Multimedia

Laurent Guiraud

2001-01-01

Lifting a handling device for dismounting the pressure bells, which are inside the cylindrical magnet coil on the central section of OPAL, on the right part of the photo. OPAL was a detector on the LEP accelerator, which ran from 1989 to 2000.

Study of interaction of electromagnetic waves with thin rotating cylindrical shell of conductor in vicinity of weakly gravitating string

International Nuclear Information System (INIS)

Muminov, A.T.

2004-01-01

Full text: As it shown in the work [1,2], interaction of electromagnetic wave with rotating cylindrical shell of conductor leads to an interesting phenomenon of energy transmission from rotating body to the wave. We study influence of the gravitational field of the string on the process of interaction of electromagnetic waves with infinitesimally thin conducting cylindrical shell. Since in the outer space and inside the shell electromagnetic field satisfies source free Maxwell equations we start with constructing the most general solutions of this equation. Then we match the fields on the cylinder with account of boundary conditions on it. Matching the fields gives expressions for reflection factors of cylindrical waves for two cases of polarization. The reflection factors for distinct wave polarizations show the ratio of outgoing energy flux to in going one. Curved cylindrical symmetric space-time with weakly gravitating string-like source is described by static metric: δs 2 = f(r)δt 2 - h(r)(δz 2 + δr 2 ) - l(r)δψ 2 ; f(r) = r ε ; h(r) = r -ε ; l(r) = r 2 /f(r). Which corresponds to low line density of mass ε on the string. The metric is particular case of Lewis metric [3,4] with zero angular momentum of the string and its weak gravity. The boundary value problem for electromagnetic waves interaction with thin conducting rotating cylindrical shell in static cylindrical metric with weakly gravitating string has been solved analytically. It is found that character of dependence of the factors on Ω at ω R<<1 and ΩR<<1 approximation remains the same as in flat space-time ε =0. Analysis of expressions for the reflection factors in frames of considered approximation has been done

Cylindric partitions, {{\\boldsymbol{ W }}}_{r} characters and the Andrews-Gordon-Bressoud identities

Science.gov (United States)

Foda, O.; Welsh, T. A.

2016-04-01

We study the Andrews-Gordon-Bressoud (AGB) generalisations of the Rogers-Ramanujan q-series identities in the context of cylindric partitions. We recall the definition of r-cylindric partitions, and provide a simple proof of Borodin’s product expression for their generating functions, that can be regarded as a limiting case of an unpublished proof by Krattenthaler. We also recall the relationships between the r-cylindric partition generating functions, the principal characters of {\\hat{{sl}}}r algebras, the {{\\boldsymbol{ M }}}r r,r+d minimal model characters of {{\\boldsymbol{ W }}}r algebras, and the r-string abaci generating functions, providing simple proofs for each. We then set r = 2, and use two-cylindric partitions to re-derive the AGB identities as follows. Firstly, we use Borodin’s product expression for the generating functions of the two-cylindric partitions with infinitely long parts, to obtain the product sides of the AGB identities, times a factor {(q;q)}∞ -1, which is the generating function of ordinary partitions. Next, we obtain a bijection from the two-cylindric partitions, via two-string abaci, into decorated versions of Bressoud’s restricted lattice paths. Extending Bressoud’s method of transforming between restricted paths that obey different restrictions, we obtain sum expressions with manifestly non-negative coefficients for the generating functions of the two-cylindric partitions which contains a factor {(q;q)}∞ -1. Equating the product and sum expressions of the same two-cylindric partitions, and canceling a factor of {(q;q)}∞ -1 on each side, we obtain the AGB identities.

Micropatterning on cylindrical surfaces via electrochemical etching using laser masking

International Nuclear Information System (INIS)

Cho, Chull Hee; Shin, Hong Shik; Chu, Chong Nam

2014-01-01

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

Forced vibrations of rotating circular cylindrical shells

International Nuclear Information System (INIS)

Igawa, Hirotaka; Maruyama, Yoshiyuki; Endo, Mitsuru

1995-01-01

Forced vibrations of rotating circular cylindrical shells are investigated. Basic equations, including the effect of initial stress due to rotation, are formulated by the finite-element method. The characteristic relations for finite elements are derived from the energy principle by considering the finite strain. The equations of motion can be separated into quasi-static and dynamic ones, i.e., the equations in the steady rotating state and those in the vibration state. Radial concentrated impulses are considered as the external dynamic force. The transient responses of circular cylindrical shells are numerically calculated under various boundary conditions and rotating speeds. (author)

Vibrational analysis of submerged cylindrical shells based on elastic foundations

International Nuclear Information System (INIS)

Shah, A.G.; Naeem, M.N.

2014-01-01

In this study a vibration analysis was performed of an isotropic cylindrical shell submerged in fluid, resting on Winkler and Pasternak elastic foundations for simply supported boundary condition. Love's thin shell theory was exploited for strain- and curvature- displacement relationship. Shell problem was solved by using wave propagation approach. Influence of fluid and Winkler as well as Pasternak elastic foundations were studied on the natural frequencies of submerged isotropic cylindrical shells. Results were validated by comparing with the existing results in literature. Vibration, Submerged cylindrical shell, Love's thin shell theory, Wave propagation method, Winkler and Pasternak foundations. (author)

Cylindrical thin-shell wormholes

International Nuclear Information System (INIS)

Eiroa, Ernesto F.; Simeone, Claudio

2004-01-01

A general formalism for the dynamics of nonrotating cylindrical thin-shell wormholes is developed. The time evolution of the throat is explicitly obtained for thin-shell wormholes whose metric has the form associated with local cosmic strings. It is found that the throat collapses to zero radius, remains static, or expands forever, depending only on the sign of its initial velocity

Formation of vortex breakdown in conical–cylindrical cavities

International Nuclear Information System (INIS)

Martins, Diego Alves de Moro; Souza, Francisco José de; Salvo, Ricardo de Vasconcelos

2014-01-01

Highlights: • Rotating flows in conical–cylindrical cavities were simulated via an in-house code using unstructured meshes. • The vortex breakdown phenomenon was verified in the geometries analyzed. • The influence of Stewartson and Bödewadt layers was observed in the vortex breakdown formation. • A curve of stability and number of breakdowns was obtained as a function of Reynolds number. • Spiral vortex breakdown was observed in some situations. - Abstract: Numerical simulations in confined rotating flows were performed in this work, in order to verify and characterize the formation of the vortex breakdown phenomenon. Cylindrical and conical–cylindrical geometries, both closed, were used in the simulations. The rotating flow is induced by the bottom wall, which rotates at constant angular velocity. Firstly the numerical results were compared to experimental results available in references, with the purpose to verify the capacity of the computational code to predict the vortex breakdown phenomenon. Further, several simulations varying the parameters which govern the characteristics of the flows analyzed in this work, i.e., the Reynolds number and the aspect ratio, were performed. In these simulations, the limits for the transitional regime and the vortex breakdown formation were verified. Steady and transient cases, with and without turbulence modeling, were simulated. In general, some aspects of the process of vortex breakdown in conical–cylindrical geometries were observed to be different from that in cylinders

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...

arXiv The new cylindrical GEM inner tracker of BESIII

CERN Document Server

Lavezzi, L.; Amoroso, A.; Ferroli, R. Baldini; Bertani, M.; Bettoni, D.; Bianchi, F.; Calcaterra, A.; Canale, N.; Capodiferro, M.; Carassiti, V.; Cerioni, S.; Chai, Jy; Chiozzi, S.; Cibinetto, G.; Cossio, F.; Cotta Ramusino, A.; De Mori, F.; Destefanis, M.; Dong, J.; Evangelisti, F.; Farinelli, R.; Fava, L.; Felici, G.; Fioravanti, E.; Garzia, I.; Gatta, M.; Greco, M.; Leng, Cy; Li, H.; Maggiora, M.; Malaguti, R.; Marcello, S.; Melchiorri, M.; Mezzadri, G.; Mignone, M.; Morello, G.; Pacetti, S.; Patteri, P.; Pellegrino, J.; Pelosi, A.; Rivetti, A.; Rolo,; Savrié, M.; Scodeggio, M.; Soldani, E.; Sosio, S.; Spataro, S.; Tskhadadze, E.; Verma, S.; Wheadon, R.; Yan, L.

2018-05-03

The Cylindrical GEM-Inner Tracker (CGEM-IT) is the upgrade of the internal tracking system of the BESIII experiment. It consists of three layers of cylindrically-shaped triple GEMs, with important innovations with respect to the existing GEM detectors, in order to achieve the best performance with the lowest material budget. It will be the first cylindrical GEM running with analog readout inside a 1T magnetic field. The simultaneous measurement of both the deposited charge and the signal time will permit to use a combination of two algorithms to evaluate the spatial position of the charged tracks inside the CGEM-IT: the charge centroid and the micro time projection chamber modes. They are complementary and can cope with the asymmetry of the electron avalanche when running in magnetic field and with non-orthogonal incident tracks. To evaluate the behaviour under different working settings, both planar chambers and the first cylindrical prototype have been tested during various test beams at CERN with 150 GeV/c...

Spatial structure of radio frequency ring-shaped magnetized discharge sputtering plasma using two facing ZnO/Al2O3 cylindrical targets for Al-doped ZnO thin film preparation

Directory of Open Access Journals (Sweden)

Takashi Sumiyama

2017-05-01

Full Text Available Spatial structure of high-density radio frequency ring-shaped magnetized discharge plasma sputtering with two facing ZnO/Al2O3 cylindrical targets mounted in ring-shaped hollow cathode has been measured and Al-doped ZnO (AZO thin film is deposited without substrate heating. The plasma density has a peak at ring-shaped hollow trench near the cathode. The radial profile becomes uniform with increasing the distance from the target cathode. A low ion current flowing to the substrate of 0.19 mA/cm2 is attained. Large area AZO films with a resistivity of 4.1 – 6.7×10-4 Ω cm can be prepared at a substrate room temperature. The transmittance is 84.5 % in a visible region. The surface roughnesses of AZO films are 0.86, 0.68, 0.64, 1.7 nm at radial positions of r = 0, 15, 30, 40 mm, respectively, while diffraction peak of AZO films is 34.26°. The grains exhibit a preferential orientation along (002 axis.

Micromagnetic simulations of cylindrical magnetic nanowires

KAUST Repository

Ivanov, Yurii P.; Chubykalo-Fesenko, O.

2015-01-01

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

Shock waves in P-bar target

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhijing; Anderson, K.

1991-11-01

The deposition of large amount of beam energy in short time will cause high temperature and pressure in the center of P-bar Target, and this disturbance will propagate outwards as a shock wave. Shock wave induced material changes which are of our concern include void growth and accompanying density decrease which will decrease antiproton yield, and crack formation and fracture as was observed in tungsten target which will destroy the integrity of the target. Our objective is to analyze the shock wave behavior in the target, optimize its design so that the destructive effects of shock wave can be minimized, the integrity of the target can be maintained, and a reasonably high yield of antiproton production can be achieved. In this report we put together some results of our analysis of a cylindrical copper target. We hope that it will provide a general overview of the shock wave phenomena in the target, establish a basis for further research, and facilitate the target design. First, energy deposition data are analyzed, and it is justified that as an approximation, the problem can be treated as axi-symmetric. The average data therefore are used as energy profile, however, the maximum energy deposition are still used as the peak value. Next some basic estimations are made as to what temperature and pressure can reach at present level of energy deposition. Then some characteristics of wave propagation in a thermal shock loaded solid are illustrated with a one-dimensional model. Since there is no analytical solution available for cylindrical geometry, our understanding of the problem relies on numerical model, which are performed via finite element package ANSYS. results of numerical analysis are summarized, sources of potential danger are identified, and design ideas to minimize the damage are proposed.

Shock waves in P-bar target

International Nuclear Information System (INIS)

Tang, Zhijing; Anderson, K.

1991-11-01

The deposition of large amount of beam energy in short time will cause high temperature and pressure in the center of P-bar Target, and this disturbance will propagate outwards as a shock wave. Shock wave induced material changes which are of our concern include void growth and accompanying density decrease which will decrease antiproton yield, and crack formation and fracture as was observed in tungsten target which will destroy the integrity of the target. Our objective is to analyze the shock wave behavior in the target, optimize its design so that the destructive effects of shock wave can be minimized, the integrity of the target can be maintained, and a reasonably high yield of antiproton production can be achieved. In this report we put together some results of our analysis of a cylindrical copper target. We hope that it will provide a general overview of the shock wave phenomena in the target, establish a basis for further research, and facilitate the target design. First, energy deposition data are analyzed, and it is justified that as an approximation, the problem can be treated as axi-symmetric. The average data therefore are used as energy profile, however, the maximum energy deposition are still used as the peak value. Next some basic estimations are made as to what temperature and pressure can reach at present level of energy deposition. Then some characteristics of wave propagation in a thermal shock loaded solid are illustrated with a one-dimensional model. Since there is no analytical solution available for cylindrical geometry, our understanding of the problem relies on numerical model, which are performed via finite element package ANSYS. results of numerical analysis are summarized, sources of potential danger are identified, and design ideas to minimize the damage are proposed

Rotation, inversion and perversion in anisotropic elastic cylindrical tubes and membranes

KAUST Repository

Goriely, A.; Tabor, M.

2013-01-01

Cylindrical tubes and membranes are universal structural elements found in biology and engineering over a wide range of scales.Working in the framework of nonlinear elasticity, we consider the possible deformations of elastic cylindrical shells

Eddy current testing probe with dual half-cylindrical coils

Science.gov (United States)

Bae, Byung-Hoon; Choi, Jung-Mi; Kim, Soo-Yong

2000-02-01

We have developed a new eddy current probe composed of a dual half-cylindrical (2HC) coil as an exciting coil and a sensing coil that is placed in the small gap of the 2HC coil. The 2HC coil induces a linear eddy current on the narrow region within the target medium. The magnitude of eddy current has a maximum peak with the narrow width, underneath the center of the exciting 2HC coil. Because of the linear eddy current, the probe can be used to detect not only the existence of a crack but also its direction in conducting materials. Using specimen with a machined crack, and varying the exciting frequency from 0.5 to 100 kHz, we investigated the relationships between the direction of crack and the output voltage of the sensing coil.

Spin-wave propagation spectrum in magnetization-modulated cylindrical nanowires

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi-xiong; Wang, Meng-ning; Nie, Yao-zhuang; Wang, Dao-wei; Xia, Qing-lin [School of Physics and Electronics, Central South University, Changsha 410083 (China); Tang, Wei [School of Physics and Electronics, Central South University, Changsha 410083 (China); Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zeng, Zhong-ming [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn [School of Physics and Electronics, Central South University, Changsha 410083 (China)

2016-09-15

Spin-wave propagation in periodic magnetization-modulated cylindrical nanowires is studied by micromagnetic simulation. Spin wave scattering at the interface of two magnetization segments causes a spin-wave band structure, which can be effectively tuned by changing either the magnetization modulation level or the period of the cylindrical nanowire magnonic crystal. The bandgap width is oscillating with either the period or magnetization modulation due to the oscillating variation of the spin wave transmission coefficient through the interface of the two magnetization segments. Analytical calculation based on band theory is used to account for the micromagnetic simulation results. - Highlights: • A magnetization-modulated cylindrical nanowire magnonic crystal is proposed. • Propagating characteristics of spin waves in such magnonic crystal are studied. • Spin-wave spectra can be manipulated by changing modulation level and period.

Cylindrical concave body of composite fibrous material

International Nuclear Information System (INIS)

1979-01-01

The invention is concerned with a cylindrical concave body of compound fibrous material which is intended to be exposed to high rotation speeds around its own longitudinal axis. The concave body in question has at least one layer of fibrils that are interwoven and enclose an identical angle with the longitudinal axis of the concave body in both directions. The concave body in question also has at least a second layer of fibrils that run in the direction of the circumference and are fitted radially to the outside. The cylindrical concave body of the invention is particularly well suited for application as a rotor tube in a gas ultra-centrifuge

Investigation on the Effect of a Pre-Center Drill Hole and Tool Material on Thrust Force, Surface Roughness, and Cylindricity in the Drilling of Al7075.

Science.gov (United States)

Ghasemi, Amir Hossein; Khorasani, Amir Mahyar; Gibson, Ian

2018-01-16

Drilling is one of the most useful metal cutting processes and is used in various applications, such as aerospace, electronics, and automotive. In traditional drilling methods, the thrust force, torque, tolerance, and tribology (surface roughness) are related to the cutting condition and tool geometry. In this paper, the effects of a pre-center drill hole, tool material, and drilling strategy (including continuous and non-continuous feed) on thrust force, surface roughness, and dimensional accuracy (cylindricity) have been investigated. The results show that using pre-center drill holes leads to a reduction of the engagement force and an improvement in the surface quality and cylindricity. Non-continuous drilling reduces the average thrust force and cylindricity value, and High Speed Steels HSS-Mo (high steel speed + 5-8% Mo) reduces the maximum quantity of cutting forces. Moreover, cylindricity is directly related to cutting temperature and is improved by using a non-continuous drilling strategy.

Investigation on the Effect of a Pre-Center Drill Hole and Tool Material on Thrust Force, Surface Roughness, and Cylindricity in the Drilling of Al7075

Directory of Open Access Journals (Sweden)

Amir Hossein Ghasemi

2018-01-01

Full Text Available Drilling is one of the most useful metal cutting processes and is used in various applications, such as aerospace, electronics, and automotive. In traditional drilling methods, the thrust force, torque, tolerance, and tribology (surface roughness are related to the cutting condition and tool geometry. In this paper, the effects of a pre-center drill hole, tool material, and drilling strategy (including continuous and non-continuous feed on thrust force, surface roughness, and dimensional accuracy (cylindricity have been investigated. The results show that using pre-center drill holes leads to a reduction of the engagement force and an improvement in the surface quality and cylindricity. Non-continuous drilling reduces the average thrust force and cylindricity value, and High Speed Steels HSS-Mo (high steel speed + 5–8% Mo reduces the maximum quantity of cutting forces. Moreover, cylindricity is directly related to cutting temperature and is improved by using a non-continuous drilling strategy.

Numerical investigation of magnetic field effect on pressure in cylindrical and hemispherical silicon CZ crystal growth

International Nuclear Information System (INIS)

Mokhtari, F.; Bouabdallah, A.; Merah, A.; Oualli, H.

2012-01-01

The effect of axial magnetic field of different intensities on pressure in silicon Czochralski crystal growth is investigated in cylindrical and hemispherical geometries with rotating crystal and crucible and thermocapillary convection. As one important thermodynamic variable, the pressure is found to be more sensitive than temperature to magnetic field with strong dependence upon the vorticity field. The pressure at the triple point is proposed as a convenient parameter to control the homogeneity of the grown crystal. With a gradual increase of the magnetic field intensity the convection effect can be reduced without thermal fluctuations in the silicon melt. An evaluation of the magnetic interaction parameter critical value corresponding to flow, pressure and temperature homogenization leads to the important result that a relatively low axial magnetic field is required for the spherical system comparatively to the cylindrical one. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Numerical investigation of magnetic field effect on pressure in cylindrical and hemispherical silicon CZ crystal growth

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, F. [Universite Mouloud Mammeri de Tizi Ouzou (Algeria); LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); Bouabdallah, A. [LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); Merah, A. [LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); M' hamed Bougara University, Boumerdes (Algeria); Oualli, H. [EMP, Bordj ElBahri, Algiers (Algeria)

2012-12-15

The effect of axial magnetic field of different intensities on pressure in silicon Czochralski crystal growth is investigated in cylindrical and hemispherical geometries with rotating crystal and crucible and thermocapillary convection. As one important thermodynamic variable, the pressure is found to be more sensitive than temperature to magnetic field with strong dependence upon the vorticity field. The pressure at the triple point is proposed as a convenient parameter to control the homogeneity of the grown crystal. With a gradual increase of the magnetic field intensity the convection effect can be reduced without thermal fluctuations in the silicon melt. An evaluation of the magnetic interaction parameter critical value corresponding to flow, pressure and temperature homogenization leads to the important result that a relatively low axial magnetic field is required for the spherical system comparatively to the cylindrical one. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A Novel Vibration Mode Testing Method for Cylindrical Resonators Based on Microphones

Directory of Open Access Journals (Sweden)

Yongmeng Zhang

2015-01-01

Full Text Available Non-contact testing is an important method for the study of the vibrating characteristic of cylindrical resonators. For the vibratory cylinder gyroscope excited by piezo-electric electrodes, mode testing of the cylindrical resonator is difficult. In this paper, a novel vibration testing method for cylindrical resonators is proposed. This method uses a MEMS microphone, which has the characteristics of small size and accurate directivity, to measure the vibration of the cylindrical resonator. A testing system was established, then the system was used to measure the vibration mode of the resonator. The experimental results show that the orientation resolution of the node of the vibration mode is better than 0.1°. This method also has the advantages of low cost and easy operation. It can be used in vibration testing and provide accurate results, which is important for the study of the vibration mode and thermal stability of vibratory cylindrical gyroscopes.

Weakly nonlinear incompressible Rayleigh-Taylor instability growth at cylindrically convergent interfaces

International Nuclear Information System (INIS)

Wang, L. F.; He, X. T.; Wu, J. F.; Zhang, W. Y.; Ye, W. H.

2013-01-01

A weakly nonlinear (WN) model has been developed for the incompressible Rayleigh-Taylor instability (RTI) in cylindrical geometry. The transition from linear to nonlinear growth is analytically investigated via a third-order solutions for the cylindrical RTI initiated by a single-mode velocity perturbation. The third-order solutions can depict the early stage of the interface asymmetry due to the bubble-spike formation, as well as the saturation of the linear (exponential) growth of the fundamental mode. The WN results in planar RTI [Wang et al., Phys. Plasmas 19, 112706 (2012)] are recovered in the limit of high-mode number perturbations. The difference between the WN growth of the RTI in cylindrical geometry and in planar geometry is discussed. It is found that the interface of the inward (outward) development spike/bubble is extruded (stretched) by the additional inertial force in cylindrical geometry compared with that in planar geometry. For interfaces with small density ratios, the inward growth bubble can grow fast than the outward growth spike in cylindrical RTI. Moreover, a reduced formula is proposed to describe the WN growth of the RTI in cylindrical geometry with an acceptable precision, especially for small-amplitude perturbations. Using the reduced formula, the nonlinear saturation amplitude of the fundamental mode and the phases of the Fourier harmonics are studied. Thus, it should be included in applications where converging geometry effects play an important role, such as the supernova explosions and inertial confinement fusion implosions.

Gravitational Instability of Cylindrical Viscoelastic Medium ...

Indian Academy of Sciences (India)

similar to that of viscoelastic fluid where both properties work together. They also ... cylindrical gravitational waves provides a strong motivation in this regard. .... which represents the solenoidal character of the magnetic field and the total stress.

On the use of lead/tin alloys as target material for the production of spallation neutrons

International Nuclear Information System (INIS)

Atchison, F.; Baumann, P.; Brys, T.; Daum, M.; Egorov, A.; Fierlinger, P.; Fuchs, P.; Henneck, R.; Joray, St.; Keil, R.; Kirch, K.; Krutova, R.; Kuehne, G.; Lebedev, V.T.; Obermeier, H.; Orlova, D.N.; Perret, Ch.; Pichlmaier, A.; Richard, Ph.; Serebrov, A.; Thies, S.

2005-01-01

We have examined the suitability of lead (Pb)/tin (Sn) alloys with atomic ratios between 4:1 and 12:1 for use as a spallation target material for the PSI spallation ultracold neutron source. The measured corrosion rate with distilled water, R c -5 cm/year, is more than a factor of 80, less than for normal Pb; this corrosion rate is satisfactory. Microscopic investigations of the surface after the exposure to water revealed no visual changes. Small angle neutron scattering showed that the alloy is mechanically stable under thermal cycling. An experimental simulation of a water-cooled spallation neutron target made of Pb/Sn pebbles with a filling factor of 60% was investigated; the pulsed proton beam was simulated using hot and cold water in the target 'cooling' circuit. With realistic operational parameters for the cooling circuit, serious deformation of the PbSn pebbles occurred which finally blocked the cooling circuit. The Pb/Sn alloys solve the corrosion problem but its mechanical properties are inadequate leading to too short a lifetime to be practical in the PSI spallation source

Facility target insert shielding assessment

Energy Technology Data Exchange (ETDEWEB)

Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-10-06

Main objective of this report is to assess the basic shielding requirements for the vertical target insert and retrieval port. We used the baseline design for the vertical target insert in our calculations. The insert sits in the 12”-diameter cylindrical shaft extending from the service alley in the top floor of the facility all the way down to the target location. The target retrieval mechanism is a long rod with the target assembly attached and running the entire length of the vertical shaft. The insert also houses the helium cooling supply and return lines each with 2” diameter. In the present study we focused on calculating the neutron and photon dose rate fields on top of the target insert/retrieval mechanism in the service alley. Additionally, we studied a few prototypical configurations of the shielding layers in the vertical insert as well as on the top.

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.

Thermal shock analysis of liquid-mercury spallation target

CERN Document Server

Ishikura, S; Futakawa, M; Hino, R; Date, H

2002-01-01

The developments of the neutron scattering facilities are carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. To estimate the structural integrity of the heavy liquid-metal (Hg) target used as a spallation neutron source in a MW-class neutron scattering facility, dynamic stress behavior due to the incident of a 1 MW-pulsed proton beam was analyzed by using FEM code. Two-type target containers with semi-cylindrical type and flat-plate type window were used as models for analyses. As a result, it is confirmed that the stress (pressure wave) generated by dynamic thermal shock becomes the largest at the center of window, and the flat-plate type window is more advantageous from the structural viewpoint than the semi-cylindrical type window. It has been understood that the stress generated in the window by the pressure wave can be treated as the secondary stress. (author)

The cylindrical GEM detector of the KLOE-2 experiment

International Nuclear Information System (INIS)

Bencivenni, G.; Ciambrone, P.; De Lucia, E.; Domenici, D.; Felici, G.; Fermani, P.; Morello, G.; Branchini, P.; Cicco, A. Di; Czerwinski, E.

2017-01-01

The KLOE-2 experiment started its data taking campaign in November 2014 with an upgraded tracking system at the DAΦNE electron-positron collider at the Frascati National Laboratory of INFN. The new tracking device, the Inner Tracker, operated together with the KLOE-2 Drift Chamber, has been installed to improve track and vertex reconstruction capabilities of the experimental apparatus. The Inner Tracker is a cylindrical GEM detector composed of four cylindrical triple-GEM detectors, each provided with an X-V strips-pads stereo readout. Although GEM detectors are already used in high energy physics experiments, this device is considered a frontier detector due to its fully-cylindrical geometry: KLOE-2 is the first experiment benefiting of this novel detector technology. Alignment and calibration of this detector will be presented together with its operating performance and reconstruction capabilities.

Cylindrical-confinement-induced phase behaviours of diblock copolymer melts

International Nuclear Information System (INIS)

Mei-Jiao, Liu; Shi-Ben, Li; Lin-Xi, Zhang; Xiang-Hong, Wang

2010-01-01

The phase behaviours of diblock copolymers under cylindrical confinement are studied in two-dimensional space by using the self-consistent field theory. Several phase parameters are adjusted to investigate the cylindrical-confinement-induced phase behaviours of diblock copolymers. A series of lamella-cylinder mixture phases, such as the mixture of broken-lamellae and cylinders and the mixture of square-lamellae and cylinders, are observed by varying the phase parameters, in which the behaviours of these mixture phases are discussed in the corresponding phase diagrams. Furthermore, the free energies of these mixture phases are investigated to illustrate their evolution processes. Our results are compared with the available observations from the experiments and simulations respectively, and they are in good agreement and provide an insight into the phase behaviours under cylindrical confinement. (cross-disciplinary physics and related areas of science and technology)

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...... test specimens is discussed in general. For the cylindrical panel, it is shown that buckling localization develops shortly after a maximum load has been attained, and this occurs for a purely elastic panel as well as for elastic-plastic panels. In a case where localization occurs after a load maximum......, 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 high...

Naturally Inspired Peptide Leads: Alanine Scanning Reveals an Actin-Targeting Thiazole Analogue of Bisebromoamide.

Science.gov (United States)

Johnston, Heather J; Boys, Sarah K; Makda, Ashraff; Carragher, Neil O; Hulme, Alison N

2016-09-02

Systematic alanine scanning of the linear peptide bisebromoamide (BBA), isolated from a marine cyanobacterium, was enabled by solid-phase peptide synthesis of thiazole analogues. The analogues have comparable cytotoxicity (nanomolar) to that of BBA, and cellular morphology assays indicated that they target the actin cytoskeleton. Pathway inhibition in human colon tumour (HCT116) cells was explored by reverse phase protein array (RPPA) analysis, which showed a dose-dependent response in IRS-1 expression. Alanine scanning reveals a structural dependence to the cytotoxicity, actin targeting and pathway inhibition, and allows a new readily synthesised lead to be proposed. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

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…

Integral-equation formulation for drift eigenmodes in cylindrically symmetric systems

International Nuclear Information System (INIS)

Linsker, R.

1980-12-01

A method for solving the integral eigenmode equation for drift waves in cylindrical (or slab) geometry is presented. A leading-order kinematic effect that has been noted in the past, but incorrectly ignored in recent integral-equation calculations, is incorporated. The present method also allows electrons to be treated with a physical mass ratio (unlike earlier work that is restricted to artificially small m/sub i//m/sub e/ owing to resolution limitations). Results for the universal mode and for the ion-temperature-gradient driven mode are presented. The kinematic effect qualitatively changes the spectrum of the ion mode, and a new second region of instability for k/sub perpendicular to/rho/sub i/greater than or equal to 1 is found

Experimental configuration of direct drive cylindrical implosions on the Omega Laser

International Nuclear Information System (INIS)

Barnes, C.W.; Tubbs, D.L.; Beck, J.B.

1998-01-01

Details about the cylindrical implosions using direct-drive irradiation on the OMEGA Laser facility are provided. The experimental configuration, including orientation, construction, and mounting of the targets is described. An attempt to characterize the modulation transfer function of the primary x-ray framing camera diagnostic results in insufficient exposure contrast but relative agreement with other determinations. The x-ray intensity of the titanium backlighter driven by the 2.5-nsec linear ramp of the laser beams is described, and the relative intensity on film is compared to similar Nova experiments. The parallax effects of different length marker layers of high-opacity dichloropolystyrene is measured, resulting in the conclusion that the marker layer length should be matched to the laser drive illumination profile

Characteristic Determination Of Self Shielding Factor And Cadmium Ratio Of Cylindrical Probe

International Nuclear Information System (INIS)

Hamzah, Amir; Budi R, Ita; Pinem, Suriam

1996-01-01

Determination of thermal, epithermal and total self shielding factor and cadmium ratio of cylindrical probe has been done by measurement and calculation. Self shielding factor can be determined by dividing probe activity to Al-alloy probe activity. Due to the lack of cylindrical probe made of Al-alloy, self shielding factor can be determined by parabolic extrapolation of measured activities to 0 cm radius to divide those activities. Theoretically, self shielding factor can be determined by making numerical solution of two dimensional integral equations using Romberg method. To simplify, the calculation is based on single collision theory with the assumption of monoenergetic neutron and isotropic distribution. For gold cylindrical probe, the calculation results are quite close to the measurement one with the relative discrepancy for activities, cadmium ratio and self shielding factor of bare probe are less then 11.5%, 3,5% and 1.5% respectively. The program can be used for the calculation of other kinds of cylindrical probes. Due to dependency to radius, cylindrical probe made of copper has the best characteristic of self shielding factor and cadmium ratio

Thermal transport contributed by the torsional phonons in cylindrical nanowires: Role of evanescent modes

International Nuclear Information System (INIS)

Xie, Zhong-Xiang; Zhang, Yong; Zhang, Li-Fu; Fan, Dian-Yuan

2017-01-01

Thermal transport contributed by the torsional phonons in cylindrical nanowires is investigated by using the isotropic elastic continuum theory. The numerical calculations for both the concavity-shaped and convexity-shaped cylindrical structures are made to reveal the role of the evanescent modes. Results show that the evanescent modes play an important role in influencing the thermal transport in such structures. For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, the evanescent modes can suppress the thermal conductance by 6 percent. It is also shown that the influence of the evanescent modes on the thermal conductance is strongly related to the attenuation length of the evanescent modes. A brief analysis of these results is given. - Highlights: • The evanescent modes play an important role in influencing thermal transport contributed by torsional phonons in cylindrical nanowires. • For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, they can suppress the thermal conductance by 6 percent.

Thermal transport contributed by the torsional phonons in cylindrical nanowires: Role of evanescent modes

Energy Technology Data Exchange (ETDEWEB)

Xie, Zhong-Xiang [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002 (China); Zhang, Yong [Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002 (China); Zhang, Li-Fu, E-mail: zhanglifu68@hotmail.com [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Fan, Dian-Yuan [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China)

2017-05-03

Thermal transport contributed by the torsional phonons in cylindrical nanowires is investigated by using the isotropic elastic continuum theory. The numerical calculations for both the concavity-shaped and convexity-shaped cylindrical structures are made to reveal the role of the evanescent modes. Results show that the evanescent modes play an important role in influencing the thermal transport in such structures. For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, the evanescent modes can suppress the thermal conductance by 6 percent. It is also shown that the influence of the evanescent modes on the thermal conductance is strongly related to the attenuation length of the evanescent modes. A brief analysis of these results is given. - Highlights: • The evanescent modes play an important role in influencing thermal transport contributed by torsional phonons in cylindrical nanowires. • For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, they can suppress the thermal conductance by 6 percent.

Experimental and numerical investigation of laser forming of cylindrical surfaces with arbitrary radius of curvature

Directory of Open Access Journals (Sweden)

Mehdi Safari

2016-09-01

Full Text Available In this work, laser forming of cylindrical surfaces with arbitrary radius of curvature is investigated experimentally and numerically. For laser forming of cylindrical surfaces with arbitrary radius of curvature, a new and comprehensive method is proposed in this paper. This method contains simple linear irradiating lines and using an analytical method, required process parameters for laser forming of a cylindrical surface with a specific radius of curvature is proposed. In this method, laser output power, laser scanning speed and laser beam diameter are selected based on laser machine and process limitations. As in the laser forming of a cylindrical surface, parallel irradiating lines are needed; therefore key parameter for production of a cylindrical surface with a specific radius of curvature is the number of irradiating lines. Hence, in the proposed analytical method, the required number of irradiating lines for production of a cylindrical surface with a specific radius of curvature is suggested. Performance of the proposed method for production of cylindrical surface with a specific radius of curvature is verified with experimental tests. The results show that using proposed analytical method, cylindrical surfaces with any radius of curvature can be produced successfully.

Determination of the shear impedance of viscoelastic liquids using cylindrical piezoceramic resonators.

Science.gov (United States)

Kiełczyński, Piotr; Pajewski, Wincenty; Szalewski, Marek

2003-03-01

In this paper, a new method for determining the rheological parameters of viscoelastic liquids is presented. To this end, we used the perturbation method applied to shear vibrations of cylindrical piezoceramic resonators. The resonator was viscoelastically loaded on the outer cylindrical surface. Due to this loading, the resonant frequency and quality factor of the resonator changed. According to the perturbation method, the change in the complex resonant frequency deltaomega = deltaomega(re) + jdeltaomega(im) is directly proportional to the specific acoustic impedance for cylindrical waves Zc of a viscoelastic liquid surrounding the resonator, i.e., deltaomega is approximately equal to jZc, where j = (-1)1/2. Hence, the measurement of the real and imaginary parts of the complex resonant frequency deltaomega determines the real part, Rc, and imaginary part, Xc, of the complex acoustic impedance for cylindrical waves Zc of an investigated liquid. Furthermore, the specific impedance ZL for plane waves was related to the specific impedance Zc for cylindrical waves. Using theoretical formulas established and the results of the experiments performed, the shear storage modulus mu and the viscosity eta for various liquids (e.g., epoxy resins) were determined. Moreover, the authors derived for cylindrical resonators a formula that relates the shift in resonant frequency to the viscosity of the liquid. This formula is analogous to the Kanazawa-Gordon formula that was derived for planar resonators and Newtonian liquids.

Dynamic plastic buckling of cylindrical and spherical shells

International Nuclear Information System (INIS)

Jones, N.; Okawa, D.M.

1975-01-01

A theoretical analysis is developed to predict the dynamic plastic buckling of a long, impulsively loaded cylindrical shell in order to examine various features of plastic buckling and to assess the importance of several approximations with previous authors have introduced in dynamic plastic buckling studies. The influence of a time-dependent circumferential membrane force, the sharpness of the peaks in the displacement and velocity amplification functions, the restrictions which are implicit when employing the Prandtl-Reuss equations in this class of problems, and the limitations due to elastic unloading are examined in some detail. A summary of all previously published theoretical investigations known to the authors is undertaken for the dynamic plastic behavior of cylindrical shells and rings which are made from rigid-plastic, rigid-visco-plastic, elastic-plastic and elastic-visco-plastic materials and subjected to initial axisymmetric impulsive velocity fields. The theoretical predictions of the dominant motions, critical mode numbers, and threshold impulses are compared and critically reviewed. An experimental investigation was also undertaken into the dynamic plastic buckling of circular rings subjected to uniformly distributed external impulsive velocities. It appears that no experiments have been reported previously on mild steel cylindrical shells with an axial length (L) less than four times the shell radius (R). The experimental values of the average final radial deflections, critical mode numbers and dimensions of the permanent wrinkles in the mild steel and some aliminium 6,061 T6 specimens are compared with all the previously published theoretical predictions and experimental results on cylindrical shells with various axial lengths. (orig./HP) [de

Measurement of the Neutron Component in a Shower Generated in a Lead Target by Relativistic Nuclear Beam

International Nuclear Information System (INIS)

Chultehm, D.; Damdinsurehn, Ts.; D'yachenko, V.M.; Ehnkhzhin, L.; Lomova, L.A.; Perelygin, V.P.; Tolstov, K.D.

1994-01-01

The present paper describes a method of determining the total number of neutrons generated in an extended lead target by relativistic nuclei and protons. It is shown that 101±20 neutrons per proton are produced in the target with the volume of 50x50x80 cm 3 at 3.65 GeV energy of protons. 11 refs., 14 figs., 1 tab

Free vibration of finite cylindrical shells by the variational method

International Nuclear Information System (INIS)

Campen, D.H. van; Huetink, J.

1975-01-01

The calculation of the free vibrations of circular cylindrical shells of finite length has been of engineer's interest for a long time. The motive for the present calculations originates from a particular type of construction at the inlet of a sodium heated superheater with helix heating bundle for SNR-Kalkar. The variational analysis is based on a modified energy functional for cylindrical shells, proposed by Koiter and resulting in Morley's equilibrium equations. As usual, the dispacement amplitude is assumed to be distributed harmonically in the circumferential direction of the shell. Following the method of Gontkevich, the dependence between the displacements of the shell middle surface and the axial shell co-ordinate is expressed approximately by a set of eigenfunctions of a free vibrating beam satisfying the desired boundary conditions. Substitution of this displacement expression into the virtual work equation for the complete shell leads to a characteristic equation determining the natural frequencies. The calculations are carried out for a clamped-clamped and a clamped-free cylinder. A comparison is given between the above numerical results and experimental and theoretical results from literature. In addition, the influence of surrounding fluid mass on the above frequencies is analysed for a clamped-clamped shell. The solution for the velocity potential used in this case differs from the solutions used in literature until now in that not only travelling waves in the axial direction are considered. (Auth.)

Dual-acting of Hybrid Compounds - A New Dawn in the Discovery of Multi-target Drugs: Lead Generation Approaches.

Science.gov (United States)

Abdolmaleki, Azizeh; Ghasemi, Jahan B

2017-01-01

Finding high quality beginning compounds is a critical job at the start of the lead generation stage for multi-target drug discovery (MTDD). Designing hybrid compounds as selective multitarget chemical entity is a challenge, opportunity, and new idea to better act against specific multiple targets. One hybrid molecule is formed by two (or more) pharmacophore group's participation. So, these new compounds often exhibit two or more activities going about as multi-target drugs (mtdrugs) and may have superior safety or efficacy. Application of integrating a range of information and sophisticated new in silico, bioinformatics, structural biology, pharmacogenomics methods may be useful to discover/design, and synthesis of the new hybrid molecules. In this regard, many rational and screening approaches have followed by medicinal chemists for the lead generation in MTDD. Here, we review some popular lead generation approaches that have been used for designing multiple ligands (DMLs). This paper focuses on dual- acting chemical entities that incorporate a part of two drugs or bioactive compounds to compose hybrid molecules. Also, it presents some of key concepts and limitations/strengths of lead generation methods by comparing combination framework method with screening approaches. Besides, a number of examples to represent applications of hybrid molecules in the drug discovery are included. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Application of the cylindrically guided wave technique for bolt and pump shaft inspections

International Nuclear Information System (INIS)

Light, G.M.; Ruescher, E.H.; Bloom, E.A.; Joshi, N.R.; Tsai, Y.M.; Liu, S.N.

1993-01-01

Elastic wave propagation in a bounded medium significantly differs from that in an unbounded medium. The bounded medium in the form of a cylinder acts like a solid waveguide directing the wave with its geometry. A continuous or a pulsed wave interacts with cylindrical boundaries producing mode-converted signals in addition to the backwall echo. The signals are received at constant time intervals directly proportional to the diameter of a solid cylindrical object such as a bolt or an anchor stud. The Cylindrically Guided Wave Technique (CGWT) makes intelligent use of the mode-converted signals, or trailing pulses, to detect corrosion wastages and cracks in cylindrical objects. (orig.)

Cylindrical Hall Thrusters with Permanent Magnets

International Nuclear Information System (INIS)

Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.

2010-01-01

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.

Cylindrically converging blast waves in air

Science.gov (United States)

Matsuo, H.; Nakamura, Y.

1981-07-01

Cylindrically converging shock waves are produced by utilizing the detonation of cylindrical explosive shells. The production and the propagation of shock waves are observed by framing and streak camera photographs, and the trajectory of shock propagations is determined by using an electrical ionization probing system. The effect of the quantity of explosives on the stability, or the axial symmetry, of shock fronts and on the strength of shocks produced is investigated. It has been shown that, for practical purposes, the approximation of shock trajectories by Guderley's formulas would be sufficiently acceptable in an unexpectedly wide region near the implosion center, and that the axial symmetry of the shock front is improved by increasing the quantity of explosives, and thus, strong shocks are produced by merely increasing the quantity of explosives. The reflected diverging shock seems to be very stable. Piezoelectric elements have also been used to detect reflected diverging waves.

Comparison of Deep Brain Stimulation Lead Targeting Accuracy and Procedure Duration between 1.5- and 3-Tesla Interventional Magnetic Resonance Imaging Systems: An Initial 12-Month Experience.

Science.gov (United States)

Southwell, Derek G; Narvid, Jared A; Martin, Alastair J; Qasim, Salman E; Starr, Philip A; Larson, Paul S

2016-01-01

Interventional magnetic resonance imaging (iMRI) allows deep brain stimulator lead placement under general anesthesia. While the accuracy of lead targeting has been described for iMRI systems utilizing 1.5-tesla magnets, a similar assessment of 3-tesla iMRI procedures has not been performed. To compare targeting accuracy, the number of lead targeting attempts, and surgical duration between procedures performed on 1.5- and 3-tesla iMRI systems. Radial targeting error, the number of targeting attempts, and procedure duration were compared between surgeries performed on 1.5- and 3-tesla iMRI systems (SmartFrame and ClearPoint systems). During the first year of operation of each system, 26 consecutive leads were implanted using the 1.5-tesla system, and 23 consecutive leads were implanted using the 3-tesla system. There was no significant difference in radial error (Mann-Whitney test, p = 0.26), number of lead placements that required multiple targeting attempts (Fisher's exact test, p = 0.59), or bilateral procedure durations between surgeries performed with the two systems (p = 0.15). Accurate DBS lead targeting can be achieved with iMRI systems utilizing either 1.5- or 3-tesla magnets. The use of a 3-tesla magnet, however, offers improved visualization of the target structures and allows comparable accuracy and efficiency of placement at the selected targets. © 2016 S. Karger AG, Basel.

Preliminary measurement performance evaluation of a new white light interferometer for cylindrical surfaces

International Nuclear Information System (INIS)

Albertazzi, Armando Jr; Pont, Alex Dal

2005-01-01

This paper introduces a new design of a white light interferometer, suitable for measurement of cylindrical or quasi-cylindrical parts. A high precision 45 deg. conical mirror is used to direct collimated light radially, making it possible to measure in true cylindrical coordinates. The image of the measurand, distorted by the conical mirror, is projected in a high resolution digital camera. A mapping algorithm is used to reconstruct the cylindrical geometry from the distorted image. The rest of the interferometer is quite similar to a conventional white light interferometer: A flat reference mirror is scanned through the measurement range while an algorithm is searching for the maximum contrast position of the interference pattern. The performance evaluation of a configuration suitable for measurement of external cylindrical surfaces is also presented in this paper. A master cylinder was used as reference. Uncertainties of about 1.0 μm were found at the present stage of development

Cylindrical plunge grinding of difficult to grind materials

International Nuclear Information System (INIS)

Nakajima, Toshikatsu; Uno, Yoshiyuki; Kayahara, Masayuki.

1983-01-01

Cylindrical plunge grinding processes of titanium alloy and nickel-base superalloys with various kinds of conventional grinding wheels, which are known as difficult to grind materials, are experimentally investigated, analyzing size generation process, grinding force, surface roughness, wheel wear, grinding ratio and so on. For grinding titanium alloy Ti-6Al-4V, GC grinding wheel yields most superior grinding results which leads to lower grinding force, smaller residual stock, less wheel wear and higher grinding ratio up to about 3 with GC 80 L 9 V wheel. Then, for grinding nickelbase superalloys Waspaloy and Rene 41, WA 150 L 9 V wheel yields better grinding results in surface roughness, wheel wear, grinding ratio without chatter vibration though grinding force is higher, and the grinding ratio about 3 is obtained. Furthermore, higher plunge speed and speed ratio result in higher grinding efficiency though grinding force, surface roughness, wheel wear increase for grinding titanium alloy and nickel-base superalloys. (author)

Circumferential buckling instability of a growing cylindrical tube

KAUST Repository

Moulton, D.E.

2011-03-01

A cylindrical elastic tube under uniform radial external pressure will buckle circumferentially to a non-circular cross-section at a critical pressure. The buckling represents an instability of the inner or outer edge of the tube. This is a common phenomenon in biological tissues, where it is referred to as mucosal folding. Here, we investigate this buckling instability in a growing elastic tube. A change in thickness due to growth can have a dramatic impact on circumferential buckling, both in the critical pressure and the buckling pattern. We consider both single- and bi-layer tubes and multiple boundary conditions. We highlight the competition between geometric effects, i.e. the change in tube dimensions, and mechanical effects, i.e. the effect of residual stress, due to differential growth. This competition can lead to non-intuitive results, such as a tube growing to be thinner and yet buckle at a higher pressure. © 2011 Elsevier Ltd. All rights reserved.

Cylindrical Induction Melter Modicon Control System

International Nuclear Information System (INIS)

Weeks, G.E.

1998-04-01

In the last several years an extensive R ampersand D program has been underway to develop a vitrification system to stabilize Americium (Am) and Curium (Cm) inventories at SRS. This report documents the Modicon control system designed for the 3 inch Cylindrical Induction Melter (CIM)

A strong focussing cylindrical electrostatic quadrupole

International Nuclear Information System (INIS)

Sheng Yaochang

1986-01-01

The construction and performance of small cylindrical electrostatic quadrupole, which is installed in JM-400 pulse electrostatic accelerator, are described. This electrostatic quadrupole is not only used in neutron generator, but also suitable for ion injector as well as for low energy electron accelerator

Photovoltaic modules with cylindrical waveguides in a system for the secondary concentration of solar radiation

Science.gov (United States)

Andreev, V. M.; Davidyuk, N. Yu.; Ionova, E. A.; Rumyantsev, V. D.

2013-09-01

The parameters of the concentrating photoelectric modules with triple-junction (InGaP/GaAs/Ge) solar cells whose focusing system contains an original secondary optical element are studied. The element consists of a plane-convex lens in optical contact with the front surface of an intermediate glass plate and a cylindrical waveguide that is located on the rear side of the glass plate above the surface of the solar element. It is demonstrated that the structure of the secondary optical element provides a wide misorientation characteristic of the concentrator and the cylindrical waveguide allows a more uniform radiation density over the surface of the solar cell. The effect of chromatic aberration in the primary and secondary optical systems on the parameters of photoelectric modules is analyzed. It is demonstrated that the presence of waveguides with a length of 3-5 mm leads to effective redistribution of radiation over the surface of the solar cell whereas shorter and longer waveguides provide the local concentration of radiation at the center of the photodetecting area.

The analytic nodal method in cylindrical geometry

International Nuclear Information System (INIS)

Prinsloo, Rian H.; Tomasevic, Djordje I.

2008-01-01

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

Research on cylindrical indexing cam’s unilateral machining

Directory of Open Access Journals (Sweden)

Junhua Chen

2015-08-01

Full Text Available The cylindrical cam ridge of the indexer is a spatial curved surface, which is difficult to design and machine. The cylindrical cam has some defects after machining because conventional machining methods have inaccuracies. This article aims at proposing a precise way to machine an indexing cam, using basic motion analysis and analytic geometry approach. Analytical methodology is first applied in the cam’s motion analysis, to obtain an error-free cam follower’s trajectory formula, and then separate the continuous trajectory curve by thousandth resolution, to create a three-dimensional discrete trajectory curve. Planar formulae and spherical formulae can be built on the loci. Based on the machine principle, the cutting cutter’s position and orientation will be taken into account. This article calculates the formula set as presented previously and obtains the ultimate cutter path coordinate value. The new error-free cutter path trajectory is called the unilateral machining trajectory. The earned results will compile into numerical control processing schedule. This processing methodology gives a convenient and precision way to manufacture a cylindrical indexing cam. Experimental results are also well supported.

Wellposedness of a cylindrical shell model

International Nuclear Information System (INIS)

McMillan, C.

1994-01-01

We consider a well-known model of a thin cylindrical shell with dissipative feedback controls on the boundary in the form of forces, shears, and moments. We show that the resulting closed loop feedback problem generates a s.c. semigroup of contractions in the energy space

On the dynamics of cylindrical z-pinch

International Nuclear Information System (INIS)

Solov'ev, L.S.

1984-01-01

The stationary configurations of cylindrical plasma flow in the framework of two-liquid relativistic electromagnetic gas dynamics (REMG)) and nonlinear radial oscillations of the plasma cylinder with longitudinal current in the framework of classical monoliquid MGD are considered. It is shown that at sufficiently high conductivity Z-pinch is stable relative to one-dimensional radial perturbations and its motion represents respectively nonlinear radial oscillations. In case of a rather low conductivity or low particle concentration there is in cross section a stability also in relation to the development of sausage type instability. The performed investigations of cylindrical equilibrium and radial oscillations give a qualitative representation on plasma behaviour in Z-pinch at the initial stage of it compression and expansion as well as on motion in an average plane of the developing sausage type instability

A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

Science.gov (United States)

Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

2016-10-01

A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum.

The affection of the disturbance of the hydrodynamics of blood in case of stress on pathological increase of level of low density lipoproteins in blood. The formation of cylindrical plaques, and their participation in the development of acute ischemic disorders of heart and brain.

Science.gov (United States)

Rusanov, S E

2017-09-01

In this article is given the new insight about the affection of stress on the increase of level of low density lipoproteins (LDL) in the blood, which is connected with the disturbance of hydrodynamics in the bloodstream, the attention was paid to the cylindrical cholesterol plaque, and it's classification. The disturbance of hydrodynamics of blood under the stress leads to the formation of a cylindrical cholesterol plaque, which repeats the contour of the vessel, and leads to the ischemic disorders of the heart and brain. The cylindrical cholesterol plaque goes through several stages of development: friable, yielding, dense, old. In the case of destruction of friable, fresh cholesterol plaque, releases a big quantity of low-density lipoproteins. This leads to the pathological increase of level of LDL in the blood. In the case of long disturbance of hydrodynamics, occurs the formation of strong links between low-density lipoproteins. Yielding cholesterol plaque is formed. Further maturation of cylindrical cholesterol plaque, leads to it's densifying and damage. We may emphasize, that short periods of strong contraction and expansion of vessels lead to the increase of level of LDL in the blood. Self-dependent restoration of normal level of LDL in blood occurs in the case of restoration of pressure in the limits of numbers, which are specific for particular person, and which don't exceed the physiological standard. Among patients with long duration of stress, the duration of vasospasm increases. LDL, without having a possibility to crumble, begin to stick together and form the yielding cylindrical plaque. It is characterized by having of not so strong connection with the vascular wall, and maintains only at the expanse of iteration of the vascular wall, it has cylindrical shape, is elastic and yellow. The thickness and length of walls depends on the degree of cross-clamping during the time of formation of yielding cylindrical plaque. In the case of stopping of spasm

Cylindrical collapse and gravitational waves

Energy Technology Data Exchange (ETDEWEB)

Herrera, L [Escuela de FIsica, Faculdad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela (Venezuela); Santos, N O [Universite Pierre et Marie Curie, CNRS/FRE 2460 LERMA/ERGA, Tour 22-12, 4eme etage, BoIte 142, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratorio Nacional de Computacao Cientifica, 25651-070 Petropolis RJ (Brazil); Centro Brasileiro de Pesquisas Fisicas, 22290-180 Rio de Janeiro RJ (Brazil)

2005-06-21

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.

Visualization of the flow in a cylindrical container with a rotating disk

Science.gov (United States)

Imahoko, Ryoki; Kurakata, Hiroki; Sakakibara, Jun

2017-11-01

We studied a behavior of the flow in a cylindrical container with a rotating disk. The apparatus consists of a fixed cylindrical container of the inner diameter of 140 mm and height H, and a coaxial rotating disc with a diameter of 140 mm connected with a cylindrical shaft driven by an electrical motor. The radial gap between rotating disk and side wall is very slight distance. The height H is variable up to 100 mm. The velocity distribution in the container was measured by means of particle image velocimetry (PIV). The results of this experiments will be discussed at the conference.

Application of Fourier-Bessel technique for computing Eigen-states in a Bragg cylindrical space slot channel waveguide

Science.gov (United States)

Jafari, Seyed Hamed; Gauthier, Robert C.

2015-02-01

Maxwell's wave equations can be solved using different techniques in order to extract optical properties of a variety of dielectric structures. For structures that contain an extended axis which serve for the reference for cylindrical symmetry, we have shown that an expansion of the fields and inverse of the relative dielectric profile using a simplified and complete set of basis functions of Fourier-Bessel terms provide access to an eigenvalue formulation from which the eigen-states can be computed. We review the steps used to convert Maxwell's equation into an eigenvalue formulation, and then proceed to discuss several applications of the technique. For cylindrically symmetric structures, the computational technique provides a significantly reduced matrix order to be populated. New target structure for the presentation consists of cylindrical space slot channel waveguide in which the channel extends in azimuthal (ϕ) direction. The channel is provided by considering the etching of external side walls of "Bragg fiber". The configuration is similar to a structure that can support whispering-gallery modes, except that the modes highest field locations are within the ambient medium of the channel. Optical properties of this structure can be best examined through ?? field component which is discontinuous by ratio of relative dielectric constants when passing air-Bragg interfaces. The ability to select Bragg dielectric properties and to introduce non-uniformities in Bragg plane spacing provides access to tuning slot channel waveguide properties and design several novel configurations.

Shear stresses around circular cylindrical openings

NARCIS (Netherlands)

Hoogenboom, P.C.J.; Van Weelden, C.; Blom, C.M.B.

2010-01-01

In this paper stress concentrations are studied around circular cylindrical openings or voids in a linear elastic continuum. The loading is such that a uniform shear stress occurs in the continuum, which is disturbed by the opening. The shear stress is in the direction of the centre axis of the

Study on magnetic field mapping within cylindrical center volume of general magnet

Energy Technology Data Exchange (ETDEWEB)

Huang, Li; Lee, Sang Jin [Uiduk University, Gyeongju (Korea, Republic of)

2016-06-15

For the magnetic field analysis or design, it is important to know the behavior of the magnetic field in an interesting space. Magnetic field mapping becomes a useful tool for the study of magnetic field. In this paper, a numerical way for mapping the magnetic field within the cylindrical center volume of magnet is presented, based on the solution of the Laplace's equation in the cylindrical coordinate system. The expression of the magnetic field can be obtained by the magnetic flux density, which measured in the mapped volume. According to the form of the expression, the measurement points are arranged with the parallel cylindrical line (PCL) method. As example, the magnetic flux density generated by an electron cyclotron resonance ion source (ECRIS) magnet and a quadrupole magnet were mapped using the PCL method, respectively. The mapping results show the PCL arrangement method is feasible and convenience to map the magnetic field within a cylindrical center volume generated by the general magnet.

Cylindrical acoustic levitator/concentrator having non-circular cross-section

Science.gov (United States)

Kaduchak, Gregory; Sinha, Dipen N.

2003-11-11

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 piezoelectric crystal which has been formed with a cylindrical cross-section 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. By deforming the circular cross-section of the transducer, the acoustic force is concentrated along axial regions parallel to the axis of the transducer. The cylinder does not require accurate alignment of a resonant cavity. The concentrated regions of acoustic force cause particles in the fluid to concentrate within the regions of acoustic force for separation from the fluid.

Self-regulating characteristics of cold neutron source with annular cylindrical moderator cell

International Nuclear Information System (INIS)

Kawai, Takeshi; Lee Chien-Hsiung; Chan Yea-Kuang; Guung Tai-Cheng; Yoshino, Hirofumi; Kawabata, Yuji; Hino, Masahiro

2001-01-01

The conditions, in which the ORPHEE type cold neutron source with an annular cylindrical moderator cell could have self-regulating characteristics, were obtained through thermodynamic considerations. From a viewpoint of engineering, it is not easy to establish these conditions because three parameters are involved even in an idealized system without the effect of the mass transfer resistance in the moderator transfer tube between the condenser and the moderator cell. The inner shell of the ORPHEE moderator cell is open in the bottom, but it is expected that only hydrogen vapor is contained in the inner shell and liquid hydrogen in the outer shell. The thermodynamic considerations show that such a state is maintained only when a liquefaction capacity of the condenser is large compared to heat lead and three parameters are optimized with a good balance. We proposed another type of a moderator cell, which has an inner cylindrical cavity with no hole in the bottom but a vapor inlet opening at the uppermost part of the cavity. In this structure, a self-regulating characteristic is established easily and the liquid level in the outer shell is maintained almost constant against thermal disturbances. Therefore it is enough to control one parameter, that is, the reservoir tank pressure corresponding to the liquefaction capacity of the condenser given by the refrigeration power of the helium refrigerator. (author)

Free and Forced Vibrations of Thick-Walled Anisotropic Cylindrical Shells

Science.gov (United States)

Marchuk, A. V.; Gnedash, S. V.; Levkovskii, S. A.

2017-03-01

Two approaches to studying the free and forced axisymmetric vibrations of cylindrical shell are proposed. They are based on the three-dimensional theory of elasticity and division of the original cylindrical shell with concentric cross-sectional circles into several coaxial cylindrical shells. One approach uses linear polynomials to approximate functions defined in plan and across the thickness. The other approach also uses linear polynomials to approximate functions defined in plan, but their variation with thickness is described by the analytical solution of a system of differential equations. Both approaches have approximation and arithmetic errors. When determining the natural frequencies by the semi-analytical finite-element method in combination with the divide and conqure method, it is convenient to find the initial frequencies by the finite-element method. The behavior of the shell during free and forced vibrations is analyzed in the case where the loading area is half the shell thickness

Investigation on Surface Roughness in Cylindrical Grinding

Science.gov (United States)

Rudrapati, Ramesh; Bandyopadhyay, Asish; Pal, Pradip Kumar

2011-01-01

Cylindrical grinding is a complex machining process. And surface roughness is often a key factor in any machining process while considering the machine tool or machining performance. Further, surface roughness is one of the measures of the technological quality of the product and is a factor that greatly influences cost and quality. The present work is related to some aspects of surface finish in the context of traverse-cut cylindrical grinding. The parameters considered have been: infeed, longitudinal feed and work speed. Taguchi quality design is used to design the experiments and to identify the significantly import parameter(s) affecting the surface roughness. By utilization of Response Surface Methodology (RSM), second order differential equation has been developed and attempts have also been made for optimization of the process in the context of surface roughness by using C- programming.

Acoustic characteristics of sand sediment with circular cylindrical pores

International Nuclear Information System (INIS)

Roh, Heui-Seol; Lee, Kang-Il; Yoon, Suk-Wang

2004-01-01

The acoustic pressure transmission coefficient and the phase velocity are experimentally measured as functions of the frequency and the porosity in sand sediment slabs with circular cylindrical pores filled with water and air. They are also theoretically estimated with the modified Biot-Attenborough (MBA) model, which uses a separate treatment of the viscous and the thermal effects in a non-rigid porous medium with water- and air-filled cylindrical pores. In this study, the fast (first kind) wave and the slow (second kind) wave are not separated in the transmitted signals through a sediment slab without the circular cylindrical pores, but they are separated in the transmitted signals through a sediment slab with pores. Both the phase velocities and the transmission coefficients of the fast wave and the slow wave in the sediment slabs with water- and air-filled cylindrical pores are sensitive to the air and the water porosities. It is proposed that the fast and the slow waves have opposite behaviors for several acoustic characteristics. The generalized tortuosity factor and the dynamic shape factor are introduced from the acoustic characteristics of the fast wave. The experimental results show reasonable agreement with the theoretical results estimated with the MBA model. These results suggest the possibility of predicting the acoustic characteristics of a sediment as functions of arbitrary water and air porosities. This study may also be applicable to understanding acoustic wave propagations in a bubbly liquid sediment for underwater applications and in cancellous bone for the diagnosis of osteoporosis.

Plasma waves in an inhomogeneous cylindrical plasma

International Nuclear Information System (INIS)

Pesic, S.S.

1976-01-01

The complete dispersion equation governing small amplitude plasma waves propagating in an inhomogeneous cylindrical plasma confined by a helical magnetic field is solved numerically. The efficiency of the wave energy thermalization in the lower hybrid frequency range is studied

Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

International Nuclear Information System (INIS)

Geurts, Bernard J.; Pratte, Pascal; Stolz, Steffen; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

2011-01-01

Advection-diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The advection-diffusion transport in a laminar Poiseuille flow is treated numerically for slender pores using a finite difference approach in cylindrical coordinates. The algebraic dependence of the penetration on the Peclet number as predicted theoretically, is confirmed by experimental findings at a variety of aspect ratios of the cylindrical pores. The effective penetration associated with a composite filtration element consisting of a set of parallel cylindrical pores is derived. The overall penetration of heterogeneous composite filtration elements shows an algebraic dependence to the fourth power on the radii of the individual pores that are contained. This gives rise to strong variations in the overall penetration in cases with uneven distributions of pore sizes, highly favoring filtration by the larger pores. The overall penetration is computed for a number of basic geometries, providing a point of reference for filtration design and experimental verification.

Energy corrections in pulsed neutron measurements for cylindrical geometry

International Nuclear Information System (INIS)

Drozdowicz, K.; Woznicka, U.

1982-01-01

A solution of the thermal neutron diffusion equation for a two-region concentric cylindrical system, with a constant neutron flux in the inner medium assumed, is given. The velocity-averaged dynamic parameters for thermal neutrons are used in the method. The corrections due to the diffusion cooling are introduced into the dynamic material buckling and into the velocity distribution of the thermal neutron flux. Detailed relations obtained for a hydrogenous moderator are given. Results of the measurements of the thermal neutron macroscopic absorption cross-sections for the samples in the two-region cylindrical systems are presented. (author)

Spherical and cylindrical particle resonator as a cloak system

Science.gov (United States)

Minin, I. V.; Minin, O. V.; Eremeev, A. I.; Tseplyaev, I. S.

2018-05-01

The concept of dielectric spherical or cylindrical particle in resonant mode as a cloak system is offered. In fundamental modes (modes with the smallest volume correspond to |m| = l, and s = 1) the field is concentrated mostly in the equatorial plane and at the surface of the sphere. Thus under resonance modes, such perturbation due to cuboid particle inserted in the spherical or cylindrical particle has almost no effect on the field forming resonance regardless of the value of internal particle material (defect) as long as this material does not cover the region where resonance takes place.

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 .

Analysis on Forced Vibration of Thin-Wall Cylindrical Shell with Nonlinear Boundary Condition

Directory of Open Access Journals (Sweden)

Qiansheng Tang

2016-01-01

Full Text Available Forced vibration of thin-wall cylindrical shell under nonlinear boundary condition was discussed in this paper. The nonlinear boundary was modeled as supported clearance in one end of shell and the restraint was assumed as linearly elastic in the radial direction. Based on Sanders’ shell theory, Lagrange equation was utilized to derive the nonlinear governing equations of cylindrical shell. The displacements in three directions were represented by beam functions and trigonometric functions. In the study of nonlinear dynamic responses of thin-wall cylindrical shell with supported clearance under external loads, the Newmark method is used to obtain time history, frequency spectrum plot, phase portraits, Poincare section, bifurcation diagrams, and three-dimensional spectrum plot with different parameters. The effects of external loads, supported clearance, and support stiffness on nonlinear dynamics behaviors of cylindrical shell with nonlinear boundary condition were discussed.

Avoiding Internal Capsule Stimulation With a New Eight-Channel Steering Deep Brain Stimulation Lead.

Science.gov (United States)

van Dijk, Kees J; Verhagen, Rens; Bour, Lo J; Heida, Ciska; Veltink, Peter H

2017-10-15

Novel deep brain stimulation (DBS) lead designs are currently entering the market, which are hypothesized to provide a way to steer the stimulation field away from neural populations responsible for side effects and towards populations responsible for beneficial effects. The objective of this study is to assess the performances of a new eight channel steering-DBS lead and compare this with a conventional cylindrical contact (CC) lead. The two leads were evaluated in a finite element electric field model combined with multicompartment neuron and axon models, representing the internal capsule (IC) fibers and subthalamic nucleus (STN) cells. We defined the optimal stimulation setting as the configuration that activated the highest percentage of STN cells, without activating any IC fibers. With this criterion, we compared monopolar stimulation using a single contact of the steering-DBS lead and CC lead, on three locations and four orientations of the lead. In addition, we performed a current steering test case by dividing the current over two contacts with the steering-DBS lead in its worst-case orientation. In most cases, the steering-DBS lead is able to stimulate a significantly higher percentage of STN cells compared to the CC lead using single contact stimulation or using a two contact current steering protocol when there is approximately a 1 mm displacement of the CC lead. The results also show that correct placement and orientation of the lead in the target remains an important aspect in achieving the optimal stimulation outcome. Currently, clinical trials are set up in Europe with a similar design as the steering-DBS lead. Our results illustrate the importance of the orientation of the new steering-DBS lead in avoiding side effects induced by stimulation of IC fibers. Therefore, in clinical trials sufficient attention should be paid to implanting the steering DBS-lead in the most effective orientation. © 2017 International Neuromodulation Society.

Errors due to the cylindrical cell approximation in lattice calculations

Energy Technology Data Exchange (ETDEWEB)

Newmarch, D A [Reactor Development Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1960-06-15

It is shown that serious errors in fine structure calculations may arise through the use of the cylindrical cell approximation together with transport theory methods. The effect of this approximation is to overestimate the ratio of the flux in the moderator to the flux in the fuel. It is demonstrated that the use of the cylindrical cell approximation gives a flux in the moderator which is considerably higher than in the fuel, even when the cell dimensions in units of mean free path tend to zero; whereas, for the case of real cells (e.g. square or hexagonal), the flux ratio must tend to unity. It is also shown that, for cylindrical cells of any size, the ratio of the flux in the moderator to flux in the fuel tends to infinity as the total neutron cross section in the moderator tends to zero; whereas the ratio remains finite for real cells. (author)

A Novel Automated Method for Analyzing Cylindrical Computed Tomography Data

Science.gov (United States)

Roth, D. J.; Burke, E. R.; Rauser, R. W.; Martin, R. E.

2011-01-01

A novel software method is presented that is applicable for analyzing cylindrical and partially cylindrical objects inspected using computed tomography. This method involves unwrapping and re-slicing data so that the CT data from the cylindrical object can be viewed as a series of 2-D sheets in the vertical direction in addition to volume rendering and normal plane views provided by traditional CT software. The method is based on interior and exterior surface edge detection and under proper conditions, is FULLY AUTOMATED and requires no input from the user except the correct voxel dimension from the CT scan. The software is available from NASA in 32- and 64-bit versions that can be applied to gigabyte-sized data sets, processing data either in random access memory or primarily on the computer hard drive. Please inquire with the presenting author if further interested. This software differentiates itself in total from other possible re-slicing software solutions due to complete automation and advanced processing and analysis capabilities.

On the symmetry of cylindrical implosions driven by a rotating beam of fast ions

International Nuclear Information System (INIS)

Basko, M.M.; Schlegel, T.; Maruhn, J.

2004-01-01

Cylindrical implosions driven by intense beams of heavy ions are one of the promising ways to create high energy density states in matter. To ensure the needed azimuthal symmetry of the beam energy deposition, it was proposed [Sharkov et al., Nucl. Instrum. Methods Phys. Res. A 464, 1 (2001)] to rotate the ion beam around the target axis. Combining analytical calculations with two-dimensional hydrodynamic simulations, a lower limit is established on the frequency ν of the beam rotation dictated by the target hydrodynamics. This limit is shown to be directly proportional to the desired radial convergence ratio C r for stepwise beam power profiles, and to C r 1/2 for smooth pulses. With a smooth pulse, 6-10 beam revolutions per pulse should be sufficient to reach C r ≅30, while a stepwise pulse requires ≅100 revolutions. Also, the upper bound on the asymmetry of the elliptical focal spot of a rotating ion beam is calculated

Electrostatic resonances and optical responses of cylindrical clusters

International Nuclear Information System (INIS)

Choy, C W; Xiao, J J; Yu, K W

2008-01-01

We developed a Green function formalism (GFF) for computing the electrostatic resonance in clusters of cylindrical particles. In the GFF, we take advantage of a surface integral equation to avoid matching the complicated boundary conditions on the surfaces of the particles. Numerical solutions of the eigenvalue equation yield a pole spectrum in the spectral representation. The pole spectrum can in turn be used to compute the optical response of these particles. For two cylindrical particles, the results are in excellent agreement with the exact results from the multiple image method and the normal mode expansion method. The results of this work can be extended to investigate the enhanced nonlinear optical responses of metal-dielectric composites, as well as optical switching in plasmonic waveguides.

Vertical load analysis of cylindrical ACS support structures

International Nuclear Information System (INIS)

Kennedy, J.M.; Belytschko, T.B.

1984-01-01

A new concept in LMFBR design ACS (above-core structures) supports which has generated some interest is to use a single large radius cylinder. The advantages of a single cylinder are reduced cost of fabrication, increased lateral stiffness, which enhances seismic resistance, and easier access to the fuel. However, the performance of these support structures when submitted to vertical loads from the core area may be substantially different, for the buckling and postbuckling behavior of a cylinder differs substantially from that of cylindrical beams. In this paper, a comparative analysis of an old prototypical support by 4 columns is compared with a cylindrical support. It is assumed that the single cylinder replaces the 4 columns in the original design. The dimensions of the two designs are compared

Cracking of anisotropic cylindrical polytropes

Energy Technology Data Exchange (ETDEWEB)

Mardan, S.A. [University of the Management and Technology, Department of Mathematics, Lahore (Pakistan); Azam, M. [University of Education, Division of Science and Technology, Lahore (Pakistan)

2017-06-15

We study the appearance of cracking in charged anisotropic cylindrical polytropes with generalized polytropic equation. We investigate the existence of cracking in two different kinds of polytropes existing in the literature through two different assumptions: (a) local density perturbation with conformally flat condition, and (b) perturbing polytropic index, charge and anisotropy parameters. We conclude that cracking appears in both kinds of polytropes for a specific range of density and model parameters. (orig.)

Method of dismantling cylindrical structure by cutting

International Nuclear Information System (INIS)

Harada, Minoru; Mitsuo, Kohei; Yokota, Isoya; Nakamura, Kenjiro.

1989-01-01

This invention concerns a method of cutting and removing cylindrical structures, for example, iron-reinforced concrete materials such as thermal shielding walls in BWR type power plants into block-like form. That is, in a method of cutting and removing the cylindrical structure from the side of the outer wall, the structural material is cut from above to below successively in the axial direction and the circumferential direction by means abrasive jet by remote operation and cut into blocks each of a predetermined size. The cut out blocks are successively taken out. Cutting of the material from above to below by remote operation and taking out of small blocks causes no hazards to human body. Upon practicing the present invention, it is preferred to use a processing device for slurry and exhaust gases for preventing scattering of activated dismantled pieces or powdery dusts. (K.M.)

A mathematical model of microalgae growth in cylindrical photobioreactor

Science.gov (United States)

Bakeri, Noorhadila Mohd; Jamaian, Siti Suhana

2017-08-01

Microalgae are unicellular organisms, which exist individually or in chains or groups but can be utilized in many applications. Researchers have done various efforts in order to increase the growth rate of microalgae. Microalgae have a potential as an effective tool for wastewater treatment, besides as a replacement for natural fuel such as coal and biodiesel. The growth of microalgae can be estimated by using Geider model, which this model is based on photosynthesis irradiance curve (PI-curve) and focused on flat panel photobioreactor. Therefore, in this study a mathematical model for microalgae growth in cylindrical photobioreactor is proposed based on the Geider model. The light irradiance is the crucial part that affects the growth rate of microalgae. The absorbed photon flux will be determined by calculating the average light irradiance in a cylindrical system illuminated by unidirectional parallel flux and considering the cylinder as a collection of differential parallelepipeds. Results from this study showed that the specific growth rate of microalgae increases until the constant level is achieved. Therefore, the proposed mathematical model can be used to estimate the rate of microalgae growth in cylindrical photobioreactor.

Resonant Excitation of a Truncated Metamaterial Cylindrical Shell by a Thin Wire Monopole

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Erentok, Aycan; Breinbjerg, Olav

2009-01-01

A truncated metamaterial cylindrical shell excited by a thin wire monopole is investigated using the integral equation technique as well as the finite element method. Simulations reveal a strong field singularity at the edge of the truncated cylindrical shell, which critically affects the matching...

Design of a cylindrical LED substrate without radiator

Science.gov (United States)

Tang, Fan; Guo, Zhenning

2017-12-01

To reduce the weight and production costs of light-emitting diode (LED) lamps, we applied the principle of the chimney effect to design a cylindrical LED substrate without a radiator. We built a 3D model by using Solidworks software and applied the flow simulation plug-in to conduct model simulation, thereby optimizing the heat source distribution and substrate thickness. The results indicate that the design achieved optimal cooling with a substrate with an upper extension length of 35 mm, a lower extension length of 8 mm, and a thickness of 1 mm. For a substrate of those dimensions, the highest LED chip temperature was 64.78 °C, the weight of the substrate was 35.09 g, and R jb = 7.00 K/W. If the substrate is powered at 8, 10, and 12 W, its temperature meets LED safety requirements. In physical tests, the highest temperature for a physical 8 W cylindrical LED substrate was 66 °C, which differed by only 1.22 °C from the simulation results, verifying the validity of the simulation. The designed cylindrical LED substrate can be used in high-power LED lamps that do not require radiators. This design is not only excellent for heat dissipation, but also for its low weight, low cost, and simplicity of manufacture.

Experiments on cylindrically converging blast waves in atmospheric air

Science.gov (United States)

Matsuo, Hideo; Nakamura, Yuichi

1980-06-01

Cylindrically converging blast waves have been produced in normal atmospheric conditions by the detonation of the explosives, pentaerythritoltetranitrate, (PETN), over cylindrical surfaces. The shocks generated in this way are so strong that the fronts propagating through the air become luminous of themselves. The production and the propagation of the shocks have been monitored with a framing camera and a streak camera, and the time-space relations of the shock propagations have been determined using an electrical ionization probing system. The results have shown that the trajectory of the shock fronts near the axis of the cylinder can be approximately represented by the Guderley's formula.

Metallurgical Evaluation of the Five-Inch Cylindrical Induction Melter

International Nuclear Information System (INIS)

Imrich, K.J.

2000-01-01

A metallurgical evaluation of the 5-inch cylindrical induction melter (CIM) vessel was performed by the Materials Technology Section to evaluate the metallurgical condition after operating for approximately 375 hours at 1400 to 1500 Degrees Celsius during a 2 year period. Results indicate that wall thinning and significant grain growth occurred in the lower portion of the conical section and the drain tube. No through-wall penetrations were found in the cylindrical and conical sections of the CIM vessel and only one leak site was identified in the drain tube. Failure of the drain tube was associated with a localized over heating and intercrystalline fracture

Dynamics of charged viscous dissipative cylindrical collapse with full causal approach

Energy Technology Data Exchange (ETDEWEB)

Shah, S.M.; Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)

2017-11-15

The aim of this paper is to investigate the dynamical aspects of a charged viscous cylindrical source by using the Misner approach. To this end, we have considered the more general charged dissipative fluid enclosed by the cylindrical symmetric spacetime. The dissipative nature of the source is due to the presence of dissipative variables in the stress-energy tensor. The dynamical equations resulting from such charged cylindrical dissipative source have been coupled with the causal transport equations for heat flux, shear and bulk viscosity, in the context of the Israel-Steward theory. In this case, we have the considered Israel-Steward transportation equations without excluding the thermodynamics viscous/heat coupling coefficients. The results are compared with the previous works in which such coefficients were excluded and viscosity variables do not satisfy the casual transportation equations. (orig.)

Continuing investigations for technology assessment of 99Mo production from LEU [low enriched uranium] targets

International Nuclear Information System (INIS)

Vandegrift, G.F.; Kwok, J.D.; Marshall, S.L.; Vissers, D.R.; Matos, J.E.

1987-01-01

Currently much of the world's supply of 99m Tc for medical purposes is produced from 99 Mo derived from the fissioning of high enriched uranium (HEU). This paper presents the results of our continuing studies on the effects of substituting low enriched uranium (LEU) for HEU in targets for the production of fission product 99 Mo. Improvements in the electrodeposition of thin films of uranium metal continue to increase the appeal for the substitution of LEU metal for HEU oxide films in cylindrical targets. The process is effective for targets fabricated from stainless steel or zircaloy. Included is a cost estimate for setting up the necessary equipment to electrodeposit uranium metal on cylindrical targets. Further investigations on the effect of LEU substitution on processing of these targets are also reported. Substitution of uranium silicides for the uranium-aluminium alloy or uranium aluminide dispersed fuel used in current target designs will allow the substitution of LEU for HEU in these targets with equivalent 99 Mo-yield per target and no change in target geometries. However, this substitution will require modifications in current processing steps due to 1) the insolubility of uranium silicides in alkaline solutions and 2) the presence of significant quantities of silicate in solution. Results to date suggest that substitution of LEU for HEU can be achieved. (Author)

NMR approaches in structure-based lead discovery: recent developments and new frontiers for targeting multi-protein complexes.

Science.gov (United States)

Dias, David M; Ciulli, Alessio

2014-01-01

Nuclear magnetic resonance (NMR) spectroscopy is a pivotal method for structure-based and fragment-based lead discovery because it is one of the most robust techniques to provide information on protein structure, dynamics and interaction at an atomic level in solution. Nowadays, in most ligand screening cascades, NMR-based methods are applied to identify and structurally validate small molecule binding. These can be high-throughput and are often used synergistically with other biophysical assays. Here, we describe current state-of-the-art in the portfolio of available NMR-based experiments that are used to aid early-stage lead discovery. We then focus on multi-protein complexes as targets and how NMR spectroscopy allows studying of interactions within the high molecular weight assemblies that make up a vast fraction of the yet untargeted proteome. Finally, we give our perspective on how currently available methods could build an improved strategy for drug discovery against such challenging targets. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

A liquid He-3 target system for use at intermediate energies

International Nuclear Information System (INIS)

Hassell, D.K.; Abegg, R.; Murdoch, B.T.; van Oers, W.J.H.; Soukup, J.

1981-04-01

A liquid 3 He target system with remote instrumentation and handling capabilities has been developed for experiments using the 180-525 MeV TRIUMF cyclotron. Helium-3 gas is liquefied by means of a 4 He cryostat into a cylindrical target cell (4.4 cm diameter, 1.6 cm thick) and maintained during operation at approximately 1.6 K. This provides an areal target density of approximately 2.7 x 10 22 He-3 nuclei/cm 2 (128 mg/cm 2 ), suitable for intermediate energy proton scattering. (author)

Digital image processing: Cylindrical surface plane development of CAREM fuel pellets

International Nuclear Information System (INIS)

Caccavelli, J; Cativa Tolosa, S; Gommes, C

2012-01-01

As part of the development of fuel pellets (FPs) for nuclear reactor CAREM-25, is necessary to systematize the analysis of the mechanical integrity of the FPs that is now done manually by a human operator. Following specifications and standards of reference for this purpose, the FPs should be inspected visually for detecting material discontinuities in the FPs surfaces to minimize any deterioration, loss of material and excessive breakage during operation and load of fuel bars. The material discontinuities are classified into two defects: surface cracks and chips. For each of these surface defects exist acceptance criteria that determine if the fuel pellet (FP) as a whole is accepted or rejected. One criteria for surface cracks is that they do not exceed one third (1/3) of the circumferential surface of the FP. The FP has cylindrical shape, so some of these acceptance criteria make difficult to analyze the FP in a single photographic image. Depending on the axial rotation of the FP, the crack could not be entirely visualized on the picture frame. Even a single crack that appears in different parts of the FP rotated images may appear to be different cracks in the FP when it is actually one. For this reason it is necessary, for the automatic detection and measurement of surface defects, obtain the circumferential surface of the FP into a single image in order to decide the acceptance or reject of the FP. As the FP shape is cylindrical, it is possible to obtain the flat development of the cylindrical surface (surface unrolling) of the FPs into a single image combining the image set of the axial rotation of the FP. In this work, we expose the procedure to implement the flat development of the cylindrical surface (surface unrolling). Starting from a photographic image of the FP surface, which represents the projection of a cylinder in the plane, we obtain three-dimensional information of each point on the cylindrical surface of the FP (3D-mapping). Then, we can

Ion currents to cylindrical Langmuir probes for finite ion temperature values: Theory

International Nuclear Information System (INIS)

Ballesteros, J.; Palop, J.I.F.; Colomer, V.; Hernandez, M.A.

1995-01-01

As it is known, the experimental ion currents to a cylindrical Langmuir probe fit quite well to the radial motion theory, developed by Allen, Boyd and Reynolds (ABR Model) and generalized by Chen for the cylindrical probe case. In this paper, we are going to develop a generalization of the ABR theory, taking into account the influence of a finite ion temperature value

Evolution of transverse instability in a hollow cylindrical weakly-ionized plasma column

International Nuclear Information System (INIS)

Kuedyan, H.M.

1978-01-01

Having observed formation of plasma striations in an Electron Cyclotron Resonance Heating (ECRH) device, we have studied the conditions under which the hollow cylindrical plasma columns would develop into striations. We first present the observed conditions of the hollow cylindrical plasma which would develop into plasma striations, the measured characteristics of the transverse oscillations and a simple small signal model for a transverse instability in a weakly-ionized hollow cylindrical plasma. This linearized model, which assumes flowing cold ion fluid (T/sub i/ approximately < 0.1 eV) in warm electron fluid (T/sub e/ approximately 1 eV) and background neutrals, reveals a transverse flute-type electrostatic instability whose characteristics are in qualitative and quantitative agreement with the measured values of the oscillations in our experiment

An investigation on cylindrical imploding turbulent mixing

International Nuclear Information System (INIS)

Liao Haidong; Yang Libin; Zhang Xilin; Ouyang Kai; Li Jun

2001-01-01

The interfacial instability experiments in cylindrically convergent geometry are performed by imploding jelly liner with high pressure gases; and instability growth were observed with high-speed framing camera. The relevant 2D numerical simulation programs were developed and their results are in good agreement with those of experiments

Numerical determination of transmission probabilities in cylindrical geometry

International Nuclear Information System (INIS)

Queiroz Bogado Leite, S. de.

1989-11-01

Efficient methods for numerical calculation of transmission probabilities in cylindrical geometry are presented. Relative errors of the order of 10 -5 or smaller are obtained using analytical solutions and low order quadrature integration schemes. (author) [pt

Quasi-cylindrical wave contribution in experiments on extraordinary optical transmission.

Science.gov (United States)

van Beijnum, Frerik; Rétif, Chris; Smiet, Chris B; Liu, Haitao; Lalanne, Philippe; van Exter, Martin P

2012-12-20

A metal film perforated by a regular array of subwavelength holes shows unexpectedly large transmission at particular wavelengths, a phenomenon known as the extraordinary optical transmission (EOT) of metal hole arrays. EOT was first attributed to surface plasmon polaritons, stimulating a renewed interest in plasmonics and metallic surfaces with subwavelength features. Experiments soon revealed that the field diffracted at a hole or slit is not a surface plasmon polariton mode alone. Further theoretical analysis predicted that the extra contribution, from quasi-cylindrical waves, also affects EOT. Here we report the experimental demonstration of the relative importance of surface plasmon polaritons and quasi-cylindrical waves in EOT by considering hole arrays of different hole densities. From the measured transmission spectra, we determine microscopic scattering parameters which allow us to show that quasi-cylindrical waves affect EOT only for high densities, when the hole spacing is roughly one wavelength. Apart from providing a deeper understanding of EOT, the determination of microscopic scattering parameters from the measurement of macroscopic optical properties paves the way to novel design strategies.

Parameterized Finite Element Modeling and Buckling Analysis of Six Typical Composite Grid Cylindrical Shells

Science.gov (United States)

Lai, Changliang; Wang, Junbiao; Liu, Chuang

2014-10-01

Six typical composite grid cylindrical shells are constructed by superimposing three basic types of ribs. Then buckling behavior and structural efficiency of these shells are analyzed under axial compression, pure bending, torsion and transverse bending by finite element (FE) models. The FE models are created by a parametrical FE modeling approach that defines FE models with original natural twisted geometry and orients cross-sections of beam elements exactly. And the approach is parameterized and coded by Patran Command Language (PCL). The demonstrations of FE modeling indicate the program enables efficient generation of FE models and facilitates parametric studies and design of grid shells. Using the program, the effects of helical angles on the buckling behavior of six typical grid cylindrical shells are determined. The results of these studies indicate that the triangle grid and rotated triangle grid cylindrical shell are more efficient than others under axial compression and pure bending, whereas under torsion and transverse bending, the hexagon grid cylindrical shell is most efficient. Additionally, buckling mode shapes are compared and provide an understanding of composite grid cylindrical shells that is useful in preliminary design of such structures.

Design algorithm for generatrix profile of cylindrical crowned rollers

Directory of Open Access Journals (Sweden)

Creţu Spiridon

2017-01-01

Full Text Available The cross-section of roller profile controls the pressure distribution in the contact area and radically affects the roller bearings basic dynamic load rating and rating lives. Today the most used roller profiles are the logarithmic profile and cylindrical-crowned (ZB profile. The logarithmic profile has a continuous evolution with no discontinuities till the intersection with the end fillet while ZB profile has two more discontinuities at the intersections points between the crowning circle and straight line generatrix. Using a semianalytical method, a numerical study has been carried out to find the optimum ZB profile for rollers incorporated in cylindrical rollers bearings. The basic reference rating life (L10_r has been used as optimization criterion.

Fragile X and autism: Intertwined at the molecular level leading to targeted treatments

Directory of Open Access Journals (Sweden)

Hagerman Randi

2010-09-01

Full Text Available Abstract Fragile X syndrome (FXS is caused by an expanded CGG repeat (> 200 repeats in the 5' untranslated portion of the fragile mental retardation 1 gene (FMR1, leading to deficiency or absence of the FMR1 protein (FMRP. FMRP is an RNA carrier protein that controls the translation of several other genes that regulate synaptic development and plasticity. Autism occurs in approximately 30% of FXS cases, and pervasive developmental disorder, not otherwise specified (PDD-NOS occurs in an additional 30% of cases. Premutation repeat expansions (55 to 200 CGG repeats may also give rise to autism spectrum disorders (ASD, including both autism and PDD-NOS, through a different molecular mechanism that involves a direct toxic effect of the expanded CGG repeat FMR1 mRNA. RNA toxicity can also lead to aging effects including tremor, ataxia and cognitive decline, termed fragile X-associated tremor ataxia syndrome (FXTAS, in premutation carriers in late life. In studies of mice bearing premutation expansions, there is evidence of early postnatal neuronal cell toxicity, presenting as reduced cell longevity, decreased dendritic arborization and altered synaptic morphology. There is also evidence of mitochondrial dysfunction in premutation carriers. Many of the problems with cellular dysregulation in both premutation and full mutation neurons also parallel the cellular abnormalities that have been documented in autism without fragile X mutations. Research regarding dysregulation of neurotransmitter systems in FXS, including the metabotropic glutamate receptor (mGluR1/5 pathway and γ aminobutyric acid (GABAA pathways, have led to new targeted treatments for FXS. Preliminary evidence suggests that these new targeted treatments will also be beneficial in non-fragile X forms of autism.

Improved spatial targeting with directionally segmented deep brain stimulation leads for treating essential tremor

Science.gov (United States)

Keane, Maureen; Deyo, Steve; Abosch, Aviva; Bajwa, Jawad A.; Johnson, Matthew D.

2012-08-01

Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to exert a therapeutic effect on postural and kinetic tremor in patients with essential tremor (ET). For DBS leads implanted near the caudal border of Vim, however, there is an increased likelihood that one will also induce paresthesia side-effects by stimulating neurons within the sensory pathway of the ventral caudal (Vc) nucleus of thalamus. The aim of this computational study was to (1) investigate the neuronal pathways modulated by therapeutic, sub-therapeutic and paresthesia-inducing DBS settings in three patients with ET and (2) determine how much better an outcome could have been achieved had these patients been implanted with a DBS lead containing directionally segmented electrodes (dDBS). Multi-compartment neuron models of the thalamocortical, cerebellothalamic and medial lemniscal pathways were first simulated in the context of patient-specific anatomies, lead placements and programming parameters from three ET patients who had been implanted with Medtronic 3389 DBS leads. The models showed that in these patients, complete suppression of tremor was associated most closely with activating an average of 62% of the cerebellothalamic afferent input into Vim (n = 10), while persistent paresthesias were associated with activating 35% of the medial lemniscal tract input into Vc thalamus (n = 12). The dDBS lead design demonstrated superior targeting of the cerebello-thalamo-cortical pathway, especially in cases of misaligned DBS leads. Given the close proximity of Vim to Vc thalamus, the models suggest that dDBS will enable clinicians to more effectively sculpt current through and around thalamus in order to achieve a more consistent therapeutic effect without inducing side-effects.

Various Parameters of the Flowing Part of a Cylindrical Molecular Vacuum Pump Effecting on Its Characteristics

Directory of Open Access Journals (Sweden)

K. E. Demikhov

2015-01-01

Full Text Available In the context of modern industry the molecular vacuum pumps (MVP are widely used. The analyzed current market of vacuum technology enables drawing a conclusion that this equipment holds one of the leading positions among the high-vacuum facilities of pumping due to their advantages such as insensitivity to the atmosphere breakthrough, ability to pump out heavy gases quickly, rapid start-up time, and oil-free pumping.The earlier developed authors’ mathematical model and calculation program are used to assess the influence efficiency of the key geometrical parameters of flowing part of the cylindrical molecular pump on its main characteristics. The obtained dependences allow us to solve a relevant, but not completely resolved as yet problem of optimizing the high-vacuum pumping facilities in case of their operation in a wide range of pressures on the suction side.The paper presents graphs of the pumping speed and ratio of the cylindrical vacuum molecular pump pressures versus various parameters of the flowing part, such as the angle of inclination of the helix, the relative diameter and the number of helical starts. Conclusions are drawn.

Material failure and inertial instabilities in a shocked imploded cylindrical aluminum sample

International Nuclear Information System (INIS)

Chandler, E.A.; Egan, P.; Stokes, J.

1998-01-01

The authors have used the LANL Pegasus Z-pinch facility to drive a thin cylindrically-convergent Al liner to ∼3 km/s to launch ∼30 GPa shocks in a 3-mm thick 10-mm-i.d. aluminum cylinder whose interior is filled with 1 atm Xe gas. The subsequent material motion of the metal and gas is diagnosed with both radial and axial flash x-rays and with optical framing cameras. Instabilities are seeded by implanting wires of assorted higher density metal parallel to the cylinder axis. The authors have done two shots, varying the target from Al 1100-O to Al 6061-T6 to explore the effect of changing material strength. The images show the spallation failure of the metal-gas interface on shock release and the effect of the seeded instabilities

Analysis of thin-walled cylindrical composite shell structures subject to axial and bending loads: Concept development, analytical modeling and experimental verification

Science.gov (United States)

Mahadev, Sthanu

Continued research and development efforts devoted in recent years have generated novel avenues towards the advancement of efficient and effective, slender laminated fiber-reinforced composite members. Numerous studies have focused on the modeling and response characterization of composite structures with particular relevance to thin-walled cylindrical composite shells. This class of shell configurations is being actively explored to fully determine their mechanical efficacy as primary aerospace structural members. The proposed research is targeted towards formulating a composite shell theory based prognosis methodology that entails an elaborate analysis and investigation of thin-walled cylindrical shell type laminated composite configurations that are highly desirable in increasing number of mechanical and aerospace applications. The prime motivation to adopt this theory arises from its superior ability to generate simple yet viable closed-form analytical solution procedure to numerous geometrically intense, inherent curvature possessing composite structures. This analytical evaluative routine offers to acquire a first-hand insight on the primary mechanical characteristics that essentially govern the behavior of slender composite shells under typical static loading conditions. Current work exposes the robustness of this mathematical framework via demonstrating its potential towards the prediction of structural properties such as axial stiffness and bending stiffness respectively. Longitudinal ply-stress computations are investigated upon deriving the global stiffness matrix model for composite cylindrical tubes with circular cross-sections. Additionally, this work employs a finite element based numerical technique to substantiate the analytical results reported for cylindrically shaped circular composite tubes. Furthermore, this concept development is extended to the study of thin-walled, open cross-sectioned, curved laminated shells that are geometrically

The effects of film thickness on the electrical, optical, and structural properties of cylindrical, rotating, magnetron-sputtered ITO films

Science.gov (United States)

Kim, Jae-Ho; Seong, Tae-Yeon; Ahn, Kyung-Jun; Chung, Kwun-Bum; Seok, Hae-Jun; Seo, Hyeong-Jin; Kim, Han-Ki

2018-05-01

We report the characteristics of Sn-doped In2O3 (ITO) films intended for use as transparent conducting electrodes; the films were prepared via a five-generation, in-line type, cylindrical, rotating magnetron sputtering (CRMS) system as a function of film thickness. By using a rotating cylindrical ITO target with high usage (∼80%), we prepared high conductivity, transparent ITO films on five-generation size glass. The effects of film thickness on the electrical, optical, morphological, and structural properties of CRMS-grown ITO films are investigated in detail to correlate the thickness and performance of ITO films. The preferred orientation changed from the (2 2 2) to the (4 0 0) plane with increasing thickness of ITO is attributed to the stability of the (4 0 0) plane against resputtering during the CRMS process. Based on X-ray diffraction, surface field emission scanning electron microscopy, and cross-sectional transmission electron microscopy, we suggest a possible mechanism to explain the preferred orientation and effects of film thickness on the performance of CRMS-grown ITO films.

An Al-doped ZnO electrode grown by highly efficient cylindrical rotating magnetron sputtering for low cost organic photovoltaics

Science.gov (United States)

Park, Jun-Hyuk; Ahn, Kyung-Jun; Park, Kang-Il; Na, Seok-In; Kim, Han-Ki

2010-03-01

We report the characteristics of Al-doped zinc oxide (AZO) films prepared by a highly efficient cylindrical rotating magnetron sputtering (CRMS) system for use as a transparent conducting electrode in cost-efficient bulk hetero-junction organic solar cells (OSCs). Using a rotating cylindrical type cathode with an AZO target, whose usage was above 80%, we were able to obtain a low cost and indium free AZO electrode with a low sheet resistance of ~4.59 Ω/sq, a high transparency of 85% in the visible wavelength region and a work function of 4.9 eV at a substrate temperature of 230 °C. Moreover, the neutral poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonate) based OSC fabricated on the CRMS-grown AZO electrode at 230 °C showed an open circuit voltage of 0.5 V, a short circuit current of 8.94 mA cm-2, a fill factor of 45% and power conversion efficiency of 2.01%, indicating that CRMS is a promising cost-efficient AZO deposition technique for low cost OSCs.

Radial force distribution changes associated with tangential force production in cylindrical grasping, and the importance of anatomical registration.

Science.gov (United States)

Pataky, Todd C; Slota, Gregory P; Latash, Mark L; Zatsiorsky, Vladimir M

2012-01-10

Radial force (F(r)) distributions describe grip force coordination about a cylindrical object. Recent studies have employed only explicit F(r) tasks, and have not normalized for anatomical variance when considering F(r) distributions. The goals of the present study were (i) to explore F(r) during tangential force production tasks, and (ii) to examine the extent to which anatomical registration (i.e. spatial normalization of anatomically analogous structures) could improve signal detectability in F(r) data. Twelve subjects grasped a vertically oriented cylindrical handle (diameter=6 cm) and matched target upward tangential forces of 10, 20, and 30 N. F(r) data were measured using a flexible pressure mat with an angular resolution of 4.8°, and were registered using piecewise-linear interpolation between five manually identified points-of-interest. Results indicate that F(r) was primarily limited to three contact regions: the distal thumb, the distal fingers, and the fingers' metatacarpal heads, and that, while increases in tangential force caused significant increases in F(r) for these regions, they did not significantly affect the F(r) distribution across the hand. Registration was found to substantially reduce between-subject variability, as indicated by both accentuated F(r) trends, and amplification of the test statistic. These results imply that, while subjects focus F(r) primarily on three anatomical regions during cylindrical grasp, inter-subject anatomical differences introduce a variability that, if not corrected for via registration, may compromise one's ability to draw anatomically relevant conclusions from grasping force data. Copyright © 2011 Elsevier Ltd. All rights reserved.

Magnetic resonance imaging inside cylindrical metal containers with an eddy current self-compensated method

International Nuclear Information System (INIS)

Han, Hui; Balcom, Bruce J

2011-01-01

Magnetic resonance imaging (MRI) measurements inside cylindrical metal structures have recently been proposed and form the basis for new high-pressure MRI studies. The critical problem for MRI inside cylindrical metal structures is significant eddy currents induced by the switched magnetic field gradients, which usually corrupt spatial and motion encoding without appropriate correction. In this work a so-called standard SPRITE (single point ramped imaging with T 1 enhancement) technique is applied for imaging inside cylindrical metal structures. We show that the standard SPRITE technique is fundamentally immune to large-scale eddy current effects and yields artifact-free high-quality images with no eddy current correction required. Standard SPRITE image acquisition avoids the complications involved in the measurement and compensation of eddy current effects for MRI with cylindrical metal structures. This work is a substantial advance toward the extension of MRI to new challenging systems, which are of practical importance

A three-dimensional elasticity solution of functionally graded piezoelectric cylindrical panels

International Nuclear Information System (INIS)

Sedighi, M R; Shakeri, M

2009-01-01

This research presents an exact solution of finitely long, simply supported, orthotropic, functionally graded piezoelectric (FGP), cylindrical shell panels under pressure and electrostatic excitation. The FGP cylindrical panel is first divided into linearly inhomogeneous elements (LIEs). The general solution of governing partial differential equations of the LIEs is obtained by separation of variables. The highly coupled partial differential equations are reduced to ordinary differential equations with variable coefficients by means of appropriate trigonometric expansion of displacements and electric potential in circumferential and axial directions. The resulting governing ordinary differential equations are solved by the Galerkin finite element method. In this procedure the quadratic shape function is used in each element. The present method is applied to several benchmark problems. The coupled electromechanical effect on the structural behavior of functionally graded piezoelectric cylindrical shell panels is evaluated. The influence of the material property gradient index on the variables of electric and mechanical fields is studied. Finally some results are compared with published results

Simulation and Visualization of Flows Laden with Cylindrical Nanoparticles in a Mixing Layer

Directory of Open Access Journals (Sweden)

Wenqian Lin

2018-01-01

Full Text Available The motion of cylindrical particles in a mixing layer is studied using the pseudospectral method and discrete particle model. The effect of the Stokes number and particle aspect ratio on the mixing and orientation distribution of cylindrical particles is analyzed. The results show that the rollup of mixing layer drives the particles to the edge of the vortex by centrifugal force. The cylindrical particles with the small Stokes number almost follow fluid streamlines and are mixed thoroughly, while those with the large Stokes number, centrifugalized and accumulated at the edge of the vortex, are poorly mixed. The mixing degree of particles becomes worse as the particle aspect ratio increases. The cylindrical particles would change their orientation under two torques and rotate around their axis of revolution aligned to the vorticity direction when the shear rate is low, while aligning on the flow-gradient plane beyond a critical shear rate value. More particles are oriented with the flow direction, and this phenomenon becomes more obvious with the decrease of the Stokes number and particle aspect ratio.

Circumferential buckling instability of a growing cylindrical tube

KAUST Repository

Moulton, D.E.; Goriely, A.

2011-01-01

A cylindrical elastic tube under uniform radial external pressure will buckle circumferentially to a non-circular cross-section at a critical pressure. The buckling represents an instability of the inner or outer edge of the tube. This is a common

A single-electron current in a cylindrical nanolayer

International Nuclear Information System (INIS)

Kazaryan, E.M.; Aghekyan, N.G.; Sarkisyan, H.A.

2012-01-01

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

Three dimensional Free Vibration and Transient Analysis of Two Directional Functionally Graded Thick Cylindrical Panels Under Impact Loading

Directory of Open Access Journals (Sweden)

Hassan Zafarmand

Full Text Available AbstractIn this paper three dimensional free vibration and transient response of a cylindrical panel made of two directional functionally graded materials (2D-FGMs based on three dimensional equations of elasticity and subjected to internal impact loading is considered. Material properties vary through both radial and axial directions continuously. The 3D graded finite element method (GFEM based on Rayleigh-Ritz energy formulation and Newmark direct integration method has been applied to solve the equations in space and time domains. The fundamental normalized natural frequency, time history of displacements and stresses in three directions and velocity of radial stress wave propagation for various values of span angel of cylindrical panel and different power law exponents have been investigated. The present results show that using 2D-FGMs leads to a more flexible design than conventional 1D-FGMs. The GFEM solution have been compared with the results of an FG thick hollow cylinder and an FG curved panel, where a good agreement between them is observed.

Full-field peak pressure prediction of shock waves from underwater explosion of cylindrical charges

NARCIS (Netherlands)

Liu, Lei; Guo, Rui; Gao, Ke; Zeng, Ming Chao

2017-01-01

Cylindrical charge is a main form in most application of explosives. By employing numerical calculation and an indirect mapping method, the relation between peak pressures from underwater explosion of cylindrical and spherical charges is investigated, and further a model to predict full-field peak

Thermoelastic buckling of plates in a cylindrical geometry against an elastic back support

International Nuclear Information System (INIS)

Simmons, L.D.; Wierman, R.W.

1980-01-01

A plate which is fixed at its edges to a strong edge support structure will develop large compressive stresses when heated from ambient temperature more rapidly than the support structure. Determining the response of the plate to this situation requires stability analysis to ascertain whether the plate might buckle, or whether the constrained thermal expansion will lead to compressive stresses exceeding the yield point because it did not buckle. A special case is considered here, both analytically and experimentally, in which the plate is curved slightly into a cylindrical shape and the convex face of the plate is against a supporting surface. This case is more complex because the buckling mode will be a harmonic rather than the fundamental mode which is usually encountered

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

Linear antenna of an arbitrary orientation and position in cylindric screen

International Nuclear Information System (INIS)

Prijmenko, S.D.; Papkovich, V.G.; Khizhnyak, N.A.

1991-01-01

An equation of the linear antenna in cylindric screen is formulated. Using the averaging method a solution of this equation for the antenna of arbitrary orientation which does not contact the screen walls or contacts them in one or two ends is received. The obtained asymptotic expression for stream permits to describe in a single manner the case of resonance and non-resonance scattering. These results may be applied in design of UHF and accelerating installations using cylindric screens charged with linear vibrators. 9 refs. (author)

Friction Compensation in the Upsetting of Cylindrical Test Specimens

DEFF Research Database (Denmark)

Christiansen, Peter; Martins, P. A. F.; Bay, Niels Oluf

2016-01-01

This manuscript presents a combined numerical andexperimental methodology for determining the stress-straincurve of metallic materials from the measurements of forceand displacement obtained in the axial compression of cylindrical test specimens with friction between the specimens and the platens....... The methodology is based on minimizing the errorbetween the average surface pressure obtained from the experimental measurements of the force and displacement and thatobtained from the slab method of analysis of metal plasticity.Three different friction models based on Coulomb friction, the constant friction...... model or combined friction models are utilized .Experimental results obtained from cylindrical and Rastegaev test specimens with different lubricants combined with the experimental determination of friction by means of ring compression tests allows compensating the effect of friction...

Fem Formulation of Heat Transfer in Cylindrical Porous Medium

Science.gov (United States)

Azeem; Khaleed, H. M. T.; Soudagar, Manzoor Elahi M.

2017-08-01

Heat transfer in porous medium can be derived from the fundamental laws of flow in porous region ass given by Henry Darcy. The fluid flow and energy transport inside the porous medium can be described with the help of momentum and energy equations. The heat transfer in cylindrical porous medium differs from its counterpart in radial and axial coordinates. The present work is focused to discuss the finite element formulation of heat transfer in cylindrical porous medium. The basic partial differential equations are derived using Darcy law which is the converted into a set of algebraic equations with the help of finite element method. The resulting equations are solved by matrix method for two solution variables involved in the coupled equations.

Performance of cylindrical-conical cyclones with different geometrical configurations

Directory of Open Access Journals (Sweden)

J.D.A.M. Santana

2001-09-01

Full Text Available The present work is a continuation of a study of the influence of geometric characteristics on the performance of reverse-flow cylindrical-conical cyclones. After studying the behavior of the pressure drop in previous work (Arnosti et al., 1998, here performance in terms of collection efficiency in the removal of particulate material is addressed. The independent variables considered in this study were inlet gas velocity (three velocities and the following dimensions of the cyclone: the cylindrical section (three heights and internal height of the gas exit duct (three heights. The tests were performed using an 3³ experimental design. Analysis of the results for overall efficiency was carried out using response surfaces and the statistical parameters were estimated from linear regression.

Flow-induced vibrations of circular cylindrical structures

International Nuclear Information System (INIS)

Chen, S.

1977-06-01

The problems of flow-induced vibrations of circular cylindrical structures are reviewed. First, the general method of analysis and classification of structural responses are presented. Then, the presentation is broken up along the lines with stationary fluid, parallel flow, and cross flow. Finally, design considerations and future research needs are pointed out. 234 references

Magnetic forces between arrays of cylindrical permanent magnets

DEFF Research Database (Denmark)

Vokoun, D.; Tomassetti, G.; Beleggia, Marco

2011-01-01

procedures. Here, we introduce analytical expressions for calculating the attraction force between two arrays of cylindrical permanent magnets and compare the predictions with experimental data obtained from force measurements with NdFeB magnets. We show that the difference between predicted and measured...

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....

Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium

Science.gov (United States)

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

2015-01-01

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. PMID:26073066

A cylindrical furnace for absorption spectral studies

Indian Academy of Sciences (India)

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 ...

Performance of a Permanent-Magnet Cylindrical Hall-Effect Thruster

Science.gov (United States)

Polzin, K. A.; Sooby, E. S.; Kimberlin, A. C.; Raites, Y.; Merino, E.; Fisch, N. J.

2009-01-01

The performance of a low-power cylindrical Hall thruster, which more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster, was measured using a planar plasma probe and a thrust stand. The field in the cylindrical thruster was produced using permanent magnets, promising a power reduction over previous cylindrical thruster iterations that employed electromagnets to generate the required magnetic field topology. Two sets of ring-shaped permanent magnets are used, and two different field configurations can be produced by reorienting the poles of one magnet relative to the other. A plasma probe measuring ion flux in the plume is used to estimate the current utilization for the two magnetic topologies. The measurements indicate that electron transport is impeded much more effectively in one configuration, implying higher thrust efficiency. Thruster performance measurements on this configuration were obtained over a power range of 70-350 W and with the cathode orifice located at three different axial positions relative to the thruster exit plane. The thrust levels over this power range were 1.25-6.5 mN, with anode efficiencies and specific impulses spanning 4-21% and 400-1950 s, respectively. The anode efficiency of the permanent-magnet thruster compares favorable with the efficiency of the electromagnet thruster when the power consumed by the electromagnets is taken into account.

Chain-based communication in cylindrical underwater wireless sensor networks.

Science.gov (United States)

Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

2015-02-04

Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate.

Chain-Based Communication in Cylindrical Underwater Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Nadeem Javaid

2015-02-01

Full Text Available Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs. Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS and Congestion adjusted PEGASIS (C-PEGASIS. Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate.

Potential containment materials for liquid-lead and lead-bismuth eutectic spallation neutron source

International Nuclear Information System (INIS)

Park, J.J.; Butt, D.P.; Beard, C.A.

1997-11-01

Lead (Pb) and lead-bismuth eutectic (44Pb-56Bi) have been the two primary candidate liquid-metal target materials for the production of spallation neutrons. Selection of a container material for the liquid-metal target will greatly affect the lifetime and safety of the target subsystem. For the lead target, niobium-1 (wt%) zirconium (Nb-1Zr) is a candidate containment material for liquid lead, but its poor oxidation resistance has been a major concern. The oxidation rate of Nb-1Zr was studied based on the calculations of thickness loss due to oxidation. According to these calculations, it appeared that uncoated Nb-1Zr may be used for a one-year operation at 900 C at P O 2 = 1 x 10 -6 torr, but the same material may not be used in argon with 5-ppm oxygen. Coating technologies to reduce the oxidation of Nb-1Zr are reviewed, as are other candidate refractory metals such as molybdenum, tantalum, and tungsten. For the Pb-Bi target, three candidate containment materials are suggested based on a literature survey of the materials compatibility and proton irradiation tests: Croloy 2-1/4, modified 9Cr-1Mo, and 12Cr-1Mo (HT-9) steel. These materials seem to be used only if the lead-bismuth is thoroughly deoxidized and treated with zirconium and magnesium

Fragmentation cross sections of relativistic 8436Kr and 10947Ag nuclei in targets from hydrogen to lead

International Nuclear Information System (INIS)

Nilsen, B.S.; Waddington, C.J.; Cummings, J.R.; Garrard, T.L.; Klarmann, J.

1995-01-01

With the addition of krypton and silver projectiles we have extended our previous studies of the fragmentation of heavy relativistic nuclei in targets ranging in mass from hydrogen to lead. These projectiles were studied at a number of discrete energies between 450 and 1500A MeV. The total and partial charge-changing cross sections were determined for each energy, target, and projectile, and the values compared with previous predictions. A new parametrization of the dependence of the total charge-changing cross sections on the target and projectile is introduced, based on nuclear charge radii derived from electron scattering. We have also parametrized the energy dependence of the total cross sections over the range of energies studied. New parameters were found for a previous representation of the partial charge-changing cross sections in hydrogen and a new parametrization has been introduced for the nonhydrogen targets. The evidence that limiting fragmentation has been attained for these relatively light projectile nuclei at Bevalac energies is shown to be inconclusive, and further measurements at higher energies will be needed to address this question

Elastic stability of cylindrical shells with soft elastic cores: Biomimicking natural tubular structures

Science.gov (United States)

Karam, Gebran Nizar

1994-01-01

Thin walled cylindrical shell structures are widespread in nature: examples include plant stems, porcupine quills, and hedgehog spines. All have an outer shell of almost fully dense material supported by a low density, cellular core. In nature, all are loaded in combination of axial compression and bending: failure is typically by buckling. Natural structures are often optimized. Here we have analyzed the elastic buckling of a thin cylindrical shell supported by an elastic core to show that this structural configuration achieves significant weight saving over a hollow cylinder. The results of the analysis are compared with data from an extensive experimental program on uniaxial compression and four point bending tests on silicone rubber shells with and without compliant foam cores. The analysis describes the results of the mechanical tests well. Characterization of the microstructures of several natural tubular structures with foamlike cores (plant stems, quills, and spines) revealed them to be close to the optimal configurations predicted by the analytical model. Biomimicking of natural cylindrical shell structures and evolutionary design processes may offer the potential to increase the mechanical efficiency of engineering cylindrical shells.

Frequency response analysis of cylindrical shells conveying fluid using finite element method

International Nuclear Information System (INIS)

Seo, Young Soo; Jeong, Weui Bong; Yoo, Wan Suk; Jeong, Ho Kyeong

2005-01-01

A finite element vibration analysis of thin-walled cylindrical shells conveying fluid with uniform velocity is presented. The dynamic behavior of thin-walled shell is based on the Sanders' theory and the fluid in cylindrical shell is considered as inviscid and incompressible so that it satisfies the Laplace's equation. A beam-like shell element is used to reduce the number of degree-of-freedom by restricting to the circumferential modes of cylindrical shell. An estimation of frequency response function of the pipe considering of the coupled effects of the internal fluid is presented. A dynamic coupling condition of the interface between the fluid and the structure is used. The effective thickness of fluid according to circumferential modes is also discussed. The influence of fluid velocity on the frequency response function is illustrated and discussed. The results by this method are compared with published results and those by commercial tools

Blue and Black Cloth Targets: Effects of Size, Shape, and Color on Stable Fly (Diptera: Muscidae) Attraction.

Science.gov (United States)

Hogsette, Jerome A; Foil, Lane D

2018-04-02

Stable fly management is challenging because of the fly's dispersal behavior and its tendency to remain on the host only while feeding. Optically attractive traps have been used to survey and sometimes reduce adult populations. Insecticide-treated blue and black cloth targets developed for tsetse fly management in Africa were found to be attractive to stable flies in the United States, and various evaluations were conducted in Louisiana and Florida. Tests using untreated targets were designed to answer questions about configuration, size, and color relative to efficacy and stability in high winds. Studies with electric grid targets and with targets paired with Olson traps showed cloth target color attraction in the following decreasing order: black > blue-black > blue. A solid black target is easier to make than a blue-black target because no sewing is involved. Attraction was not affected when flat 1-m2 targets were formed into cylinders, despite the limited view of the blue and black colors together. There was no reduction in attraction when the 1-m2 cylindrical targets were compared with smaller (63 × 30 cm high) cylindrical targets. In addition, there was no difference in attraction between the small blue-black, blue, and black targets. Significance of findings and implications of potential uses for treated targets are discussed. Target attraction was indicated by the numbers of stable flies captured on an Olson sticky trap placed 30 cm from the target. Although this system is adequate for field research, it greatly underestimates the actual numbers of stable flies attracted to treated targets.

Dynamic characteristics of a perforated cylindrical shell for flow distribution in SMART

Energy Technology Data Exchange (ETDEWEB)

Lim, Seungho; Choi, Youngin; Ha, Kyungrok [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, Kyoung-Su, E-mail: pks6348@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, No-Cheol; Park, Young-Pil [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Jeong, Kyeong-Hoon; Park, Jin-Seok [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong, Daejeon 305-303 (Korea, Republic of)

2011-10-15

Highlights: > A 1/12 scaled-down flow skirt is manufactured and a modal test is performed. > A finite element model predicts the added mass effect of the perforated cylindrical shell. > Modal characteristics are extracted by considering the fluid-structure interaction. - Abstract: The System-integrated Modular Advanced ReacTor (SMART) is a small nuclear reactor under development in Korea. It is equipped with a perforated cylindrical shell, which is called a flow skirt, in the lower plenum of the reactor for uniform flow distribution and to prevent inflow of debris into the core. This perforated cylindrical shell can be excited by external forces such as seismic or pump pulsation loads. The dynamic characteristics of the perforated cylindrical shell must be identified for further dynamic analysis. This research explores the modal analysis of the scaled-down flow skirt model submerged in coolant water. For the numerical simulation, finite element analysis is carried out to extract modal characteristics of the structure considering the fluid-structure interaction and we introduce the NAVMI factor for similarity analysis. In the finite element model, the whole shape of the perforated cylindrical shell is simulated instead of using the effective material properties. In addition, a 1/12 scaled-down flow skirt is manufactured, and an experiment is designed using an exciter and waterproof accelerometers for the modal test. Due to excellent agreement between the modal test results and the finite element analysis results such as natural frequencies and mode shapes, the finite element model is validated and can be used to predict the dynamic characteristics of the real flow skirt. Moreover, the natural frequency of the real flow skirt can be calculated from the NAVMI factor and is in good agreement with the FEM result.

The transmission probability method in one-dimensional cylindrical geometry

International Nuclear Information System (INIS)

Rubin, I.E.

1983-01-01

The collision probability method widely used in solving the problems of neutron transpopt in a reactor cell is reliable for simple cells with small number of zones. The increase of the number of zones and also taking into account the anisotropy of scattering greatly increase the scope of calculations. In order to reduce the time of calculation the transmission probability method is suggested to be used for flux calculation in one-dimensional cylindrical geometry taking into account the scattering anisotropy. The efficiency of the suggested method is verified using the one-group calculations for cylindrical cells. The use of the transmission probability method allows to present completely angular and spatial dependences is neutrons distributions without the increase in the scope of calculations. The method is especially effective in solving the multi-group problems

Research on soundproof properties of cylindrical shells of generalized phononic crystals

Science.gov (United States)

Liu, Ru; Shu, Haisheng; Wang, Xingguo

2017-04-01

Based on the previous studies, the concept of generalized phononic crystals (GPCs) is further introduced into the cylindrical shell structures in this paper. And a type of cylindrical shells of generalized phononic crystals (CS-GPCs) is constructed, the structural field and acoustic-structural coupled field of the composite cylindrical shells are examined respectively. For the structural field, the transfer matrix method of mechanical state vector is adopted to build the transfer matrix of radial waves propagating from inside to outside. For the acoustic-structural coupled field, the expressions of the acoustic transmission/reflection coefficients and the sound insulation of acoustic waves with the excitation of center line sound source are set up. And the acoustic transmission coefficient and the frequency response of sound insulation in this mode were numerical calculated. Furthermore, the theoretical analysis results are verified by using the method of combining the numerical calculation and finite element simulation. Finally, the effects of inner and outer fluid parameters on the transmission/reflection coefficients of CS-GPCs are analyzed in detail.

Cylindrical Field Effect Transistor: A Full Volume Inversion Device

KAUST Repository

Fahad, Hossain M.

2010-01-01

inversion in the body. However, these devices are still limited by lithographic and processing challenges making them unsuitable for commercial production. This thesis explores a unique device structure called the CFET (Cylindrical Field Effect Transistors

Improving the performance parameters of metal cylindrical grid shell ...

African Journals Online (AJOL)

Improving the performance parameters of metal cylindrical grid shell structures. ... Finite element models are designed taking into account minimization of production and ... The force factors and deformation parameters of the basic circuits of a ...

Rothe's method for parabolic equations on non-cylindrical domains

Czech Academy of Sciences Publication Activity Database

Dasht, J.; Engström, J.; Kufner, Alois; Persson, L.E.

2006-01-01

Roč. 1, č. 1 (2006), s. 59-80 ISSN 0973-2306 Institutional research plan: CEZ:AV0Z10190503 Keywords : parabolic equations * non-cylindrical domains * Rothe's method * time-discretization Subject RIV: BA - General Mathematics

Nonlinear Dynamic Buckling of Damaged Composite Cylindrical Shells

Institute of Scientific and Technical Information of China (English)

WANG Tian-lin; TANG Wen-yong; ZHANG Sheng-kun

2007-01-01

Based on the first order shear deformation theory(FSDT), the nonlinear dynamic equations involving transverse shear deformation and initial geometric imperfections were obtained by Hamilton's philosophy. Geometric deformation of the composite cylindrical shell was treated as the initial geometric imperfection in the dynamic equations, which were solved by the semi-analytical method in this paper. Stiffness reduction was employed for the damaged sub-layer, and the equivalent stiffness matrix was obtained for the delaminated area. By circumferential Fourier series expansions for shell displacements and loads and by using Galerkin technique, the nonlinear partial differential equations were transformed to ordinary differential equations which were finally solved by the finite difference method. The buckling was judged from shell responses by B-R criteria, and critical loads were then determined. The effect of the initial geometric deformation on the dynamic response and buckling of composite cylindrical shell was also discussed, as well as the effects of concomitant delamination and sub-layer matrix damages.

Response of cylindrical steel shell under seismic loading

International Nuclear Information System (INIS)

Tariq, M.; Amin, K.M.

2003-01-01

The seismic response of a cylindrical shell is simulated using the finite element method, and by spectral analysis. For this purpose the fundamental frequency of the cylinder is first calculated and compared with a published result. The mode shapes are also calculated which are later used for spectral analysis. The boundary nodes of the shell are displaced periodically according to a predetermined function of time by employing the acceleration time history of the El Centro earthquake to simulate the seismic loading. However, to conduct spectral analysis, the displacements are first transformed from the time domain to frequency domain using the Fast Fourier transformation. This spectral data is then used to obtain the actual displacement in the first mode under the given seismic loading. The techniques employed here can be used for cylindrical shell structures like rotor of a gas centrifuge, besides other structures that are subjected to seismic loading, besides in other time dependent loading conditions, for example rocket motor vibrations. (author)

Stresses at the intersection of two cylindrical shells

International Nuclear Information System (INIS)

Xue, M.D.; Chen, W.; Hwang, K.C.

1995-01-01

The stress analysis based on the theory of a thin shell is carried out for two normally intersecting cylindrical shells with a large diameter ratio. Instead of the Donnell shallow shell equation, the modified Morley equation, which is applicable to ρ 0 (R/T) 1/2 XXXX1, is used for the analysis of the shell with cut-out. The solution in terms of displacement function for the nozzle with a non-planar end is based on the Love equation. The boundary forces and displacements at the intersection are all transformed from Gaussian coordinates (α,β) on the shell, or Gaussian coordinates (ζ,θ) on the nozzle into three-dimensional cylindrical coordinates (ρ,θ,z). Their expressions on the intersecting curve are periodic functions of θ and expanded in Fourier series. Every harmonics of Fourier coefficients of boundary forces and displacements are obtained by numerical quadrature.The results obtained are in agreement with those from the finite element method and experiments for d/D≤0.8. ((orig.))

Cylindrization of a PWR core for neutronic calculations

International Nuclear Information System (INIS)

Santos, Rubens Souza dos

2005-01-01

In this work we propose a core cylindrization, starting from a PWR core configuration, through the use of an algorithm that becomes the process automated in the program, independent of the discretization. This approach overcomes the problem stemmed from the use of the neutron transport theory on the core boundary, in addition with the singularities associated with the presence of corners on the outer fuel element core of, existents in the light water reactors (LWR). The algorithm was implemented in a computational program used to identification of the control rod drop accident in a typical PWR core. The results showed that the algorithm presented consistent results comparing with an production code, for a problem with uniform properties. In our conclusions, we suggest, for future works, for analyzing the effect on mesh sizes for the Cylindrical geometry, and to compare the transport theory calculations versus diffusion theory, for the boundary conditions with corners, for typical PWR cores. (author)

A theoretical study of cylindrical ultrasound transducers for intracavitary hyperthermia

International Nuclear Information System (INIS)

Lin, W.-L.; Fan, W.-C.; Yen, J.-Y.; Chen, Y.-Y.; Shieh, M.-J.

2000-01-01

Purpose: The purpose of this paper was to examine the heating patterns and penetration depth when a cylindrical ultrasound transducer is employed for intracavitary hyperthermia treatments. Methods and Materials: The present study employs a simulation program based on a simplified power deposition model for infinitely long cylindrical ultrasound transducers. The ultrasound power in the tissue is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam, and a uniform attenuation for the entire treatment region is also assumed. The distribution of specific absorption rate (SAR) ratio (the ratio of SAR for a point within the tissue to that for a specific point on the cavity surface) is used to determine the heating pattern for a set of given parameters. The parameters considered are the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity. Results: Simulation results show that the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity are the most influential parameters for the distribution of SAR ratio. A low frequency transducer located in a large cavity can produce a much better penetration. The cavity size is the major parameter affecting the penetration depth for a small cavity size, such as interstitial hyperthermia. The heating pattern can also be dramatically changed by the transducer eccentricity and radiating sector. In addition, for a finite length of cylindrical transducer, lower SAR ratio appears in the regions near the applicator's edges. Conclusion: The distribution of SAR ratio indicates the relationship between the treatable region and the parameters if an appropriate threshold of SAR ratio is taken. The findings of the present study comprehend whether or not a tumor is treatable, as well as select the optimal driving frequency, the appropriate cavity size, and the eccentricity of a cylindrical transducer for a specific treatment

Structural integrity of heavy liquid-metal target installed in spallation neutron facility. Part 4: Consideration by fracture mechanics of target container window

International Nuclear Information System (INIS)

Ishikura, Syuichi; Kogawa, Hiroyuki; Futakawa, Masatoshi; Kikuchi, Kenji; Haga, Katsuhiro; Kaminaga, Masanori; Hino, Ryutaro

2004-01-01

Developments of the neutron scattering facility is carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. To estimate the structural integrity of the heavy liquid-metal (mercury) target used as a spallation neutron source in a MW-class neutron scattering facility, static and dynamic stress (including pressure wave in mercury) behaviors due to the incident of 1MW-pulsed proton beam (Maximum heat density is 461W/cc) were analyzed. In the analyses, two type target containers with semi-cylindrical type and flat-type beam windows were used as analytical models. As a result, it is confirmed that the stress generated by the pressure wave becomes the largest at the center of the beam window, and the flat-type beam window is more advantageous from the structural viewpoint than the semi-cylindrical type beam window. It has been understood that the stress generated in the beam window by the pressure wave can be treated as the secondary stress. Then, it has been understood that the stress and the stress range generated in the target window were bellow the allowable stress level defined by the standard of JIS on the maximum stress and fatigue strength. It has been experimentally confirmed that a cavitation was generated by generating the negative pressure in mercury near the target beam window and a collapse of cavitation damaged to the target container material, as pits. Then, the fracture mechanical analyses were carried out on the pit and a crack on pit tip. Consequently, it was clarified that the crack would not propagate because the inner surface of the beam window was become the compressive stress field due to the steady state thermal stress. Moreover, the evaluation technique of the cavitation which would be needed in the future was summarized. (author)

Fabrication and characterization of joined silicon carbide cylindrical components for nuclear applications

Science.gov (United States)

Khalifa, H. E.; Deck, C. P.; Gutierrez, O.; Jacobsen, G. M.; Back, C. A.

2015-02-01

The use of silicon carbide (SiC) composites as structural materials in nuclear applications necessitates the development of a viable joining method. One critical application for nuclear-grade joining is the sealing of fuel within a cylindrical cladding. This paper demonstrates cylindrical joint feasibility using a low activation nuclear-grade joint material comprised entirely of β-SiC. While many papers have considered joining material, this paper takes into consideration the joint geometry and component form factor, as well as the material performance. Work focused specifically on characterizing the strength and permeability performance of joints between cylindrical SiC-SiC composites and monolithic SiC endplugs. The effects of environment and neutron irradiation were not evaluated in this study. Joint test specimens of different geometries were evaluated in their as-fabricated state, as well as after being subjected to thermal cycling and partial mechanical loading. A butted scarf geometry supplied the best combination of high strength and low permeability. A leak rate performance of 2 × 10-9 mbar l s-1 was maintained after thermal cycling and partial mechanical loading and sustained applied force of 3.4 kN, or an apparent strength of 77 MPa. This work shows that a cylindrical SiC-SiC composite tube sealed with a butted scarf endplug provides out-of-pile strength and permeability performance that meets light water reactor design requirements.

Multi-Group Reductions of LTE Air Plasma Radiative Transfer in Cylindrical Geometries

Science.gov (United States)

Scoggins, James; Magin, Thierry Edouard Bertran; Wray, Alan; Mansour, Nagi N.

2013-01-01

Air plasma radiation in Local Thermodynamic Equilibrium (LTE) within cylindrical geometries is studied with an application towards modeling the radiative transfer inside arc-constrictors, a central component of constricted-arc arc jets. A detailed database of spectral absorption coefficients for LTE air is formulated using the NEQAIR code developed at NASA Ames Research Center. The database stores calculated absorption coefficients for 1,051,755 wavelengths between 0.04 µm and 200 µm over a wide temperature (500K to 15 000K) and pressure (0.1 atm to 10.0 atm) range. The multi-group method for spectral reduction is studied by generating a range of reductions including pure binning and banding reductions from the detailed absorption coefficient database. The accuracy of each reduction is compared to line-by-line calculations for cylindrical temperature profiles resembling typical profiles found in arc-constrictors. It is found that a reduction of only 1000 groups is sufficient to accurately model the LTE air radiation over a large temperature and pressure range. In addition to the reduction comparison, the cylindrical-slab formulation is compared with the finite-volume method for the numerical integration of the radiative flux inside cylinders with varying length. It is determined that cylindrical-slabs can be used to accurately model most arc-constrictors due to their high length to radius ratios.

A novel monolithic LEU foil target based on a PVD manufacturing process for 99Mo production via fission.

Science.gov (United States)

Hollmer, Tobias; Petry, Winfried

2016-12-01

99 Mo is the most widely used radioactive isotope in nuclear medicine. Its main production route is the fission of uranium. A major challenge for a reliable supply is the conversion from highly enriched uranium (HEU) to low enriched uranium (LEU). A promising candidate to realize this conversion is the cylindrical LEU irradiation target. The target consists of a uranium foil encapsulated between two coaxial aluminum cladding cylinders. This target allows a separate processing of the irradiated uranium foil and the cladding when recovering the 99 Mo. Thereby, both the costs and the volume of highly radioactive liquid waste are significantly reduced compared to conventional targets. The presented manufacturing process is based on the direct coating of the uranium on the inside of the outer cladding cylinder. This process was realized by a cylindrical magnetron enhanced physical vapor deposition (PVD) technique. The method features a highly automated process, a good quality of the resulting uranium foils and a high material utilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Finite element analysis of cylindrical indentation for determining plastic properties of materials in small volumes

International Nuclear Information System (INIS)

Lu, Y Charles; Kurapati, Siva N V R K; Yang Fuqian

2008-01-01

The cylindrical indentation is analysed, using the finite element method, for determining the plastic properties of elastic-plastic materials and the effect of strain hardening. The results are compared with those obtained from spherical indentation, the commonly used technique for measuring plastic properties of materials in small volumes. The analysis shows that the deformation under a cylindrical indenter quickly reaches a fully plastic state and that the size (diameter) of the plastic zone remains constant during further indentation. The indentation load is proportional to the indentation depth at large indentation depth, from which the indentation pressure P m at the onset of yielding can be readily extrapolated. The analysis of cylindrical indentation suggests that it does not need parameters such as impression radius (a) and contact stiffness (S) for determining the plastic behaviour of materials. Thus, the cylindrical indentation can suppress the uncertainties in measuring material properties

Lead-Bismuth Eutectic cooled experimental Accelerator Driven System. Windowless target unit thermal-hydraulic analysis

International Nuclear Information System (INIS)

Bianchi, F.; Ferri, R.; Moreau, V.

2004-01-01

A main concern related to the peaceful use of nuclear energy is the safe management of nuclear wastes, with particular attention to long-lived fission products. An increasing attention has recently been addressed to transmutation systems (Accelerator Driven System: ADS) able to 'burn' the actinides and some of the long-lived fission products (High-Level Waste: HLW), transforming them in short or medium-lived wastes that may be easier managed and stored in the geological disposal, with the consequent easier acceptability by population. An ADS consists of a subcritical-core coupled with an accelerator by means of a target. This paper deals with the thermal-hydraulic analysis, performed with STAR-CD and RELAP5 codes for the windowless target unit of Lead-Bismuth Eutectic (LBE) cooled experimental ADS (XADS), both to assess its behaviour during operational and accident sequences and to provide input data for the thermal-mechanical analyses. It also reports a description of modifications properly implemented in the codes used for the assessment of this kind of plants. (author)

Coulomb Green's function and image potential near a cylindrical diffuse interface

Science.gov (United States)

Xue, Changfeng; Huang, Qiongwei; Deng, Shaozhong

2015-12-01

In a preceding paper [Comput. Phys. Commun. 184 (1): 51-59, 2013], we revisited the problem of calculating Coulomb Green's function and image potential near a planar diffuse interface within which the dielectric permittivity of the inhomogeneous medium changes continuously along one Cartesian direction in a transition layer between two dissimilar dielectric materials. In the present paper, we consider a cylindrical diffuse interface within which the dielectric permittivity changes continuously along the radial direction instead. First we propose a specific cylindrical diffuse interface model, termed the quasi-harmonic diffuse interface model, that can admit analytical solution for the Green's function in terms of the modified Bessel functions. Then and more importantly we develop a robust numerical method for building Green's functions for any cylindrical diffuse interface models. The main idea of the numerical method is, after dividing a diffuse interface into multiple sublayers, to approximate the dielectric permittivity profile in each one of the sublayers by one of the quasi-harmonic functional form rather than simply by a constant value as one would normally do. Next we describe how to efficiently compute well-behaved ratios, products, and logarithmic derivatives of the modified Bessel functions so as to avoid direct evaluations of individual modified Bessel functions in our formulations. Finally we conduct numerical experiments to show the effectiveness of the quasi-harmonic diffuse interface model in overcoming the divergence of the image potential, to validate the numerical method in terms of its accuracy and convergence, and to demonstrate its capability for computing Green's functions for any cylindrical diffuse interface models.

Fluid free surface effect on the vibration analysis of cylindrical shells

International Nuclear Information System (INIS)

Lakis, A.A.; Brusuc, G.; Toorani, M.

2007-01-01

The present study is to investigate the effect of free surface motion of the fluid on the dynamic behavior of the thin-walled cylindrical shells. This paper outlines a semi-analytical approach to dynamic analysis of the fluid-filled horizontal cylindrical shell taking into account the free surface motion effect. The aim of the method is to provide a general approach that can be used for both analysis and synthesis of fluid structure interaction problems in the horizontal cylindrical shells where the dynamic interaction of a flexible structure and incompressible and inviscid flow is in focus. The approach is very general and allows for dynamic analysis of both uniform and non-uniform cylindrical shell considering the fluid forces including the sloshing effect exerted on the structure. The hybrid method developed in this work is on the basis of a combination of the classical finite element approach and the thin shell theory to determine the specific displacement functions. Mass and stiffness matrices of the shell are determined by precise analytical integration. A potential function is considered to develop the dynamic pressure due to the fluid. The kinetic and potential energies are evaluated for a range of fluid height to find the influence of the fluid on the dynamic responses of the structure. The influence of the physical and geometrical parameters on the fluid-structure system has been considered in the numerical solutions. When these results are compared with corresponding results available in the literature, both theory and experiment, very good agreement is obtained. (authors)

A potential target for organophosphate insecticides leading to spermatotoxicity.

Science.gov (United States)

Suzuki, Himiko; Tomizawa, Motohiro; Ito, Yuki; Abe, Keisuke; Noro, Yuki; Kamijima, Michihiro

2013-10-16

Organophosphate (OP) insecticides as an anticholinesterase also act on the diverse serine hydrolase targets, thereby revealing secondary or unexpected toxic effects including male reproductive toxicity. The present investigation detects a possible target molecule(s) for OP-induced spermatotoxicity (sperm deformity, underdevelopment, and reduced motility) from a chemical standpoint. The activity-based protein profiling (ABPP) approach with a phosphonofluoridate fluorescent probe pinpointed the molecular target for fenitrothion (FNT, a major OP insecticide) oxon (bioactive metabolite of FNT) in the mouse testicular membrane proteome, i.e., FNT oxon phosphorylates the fatty acid amide hydrolase (FAAH), which plays pivotal roles in spermatogenesis and sperm motility acquirement. Subsequently, mice were treated orally with vehicle or FNT for 10 days, and FAAH activity in testis or epididymis cauda was markedly reduced by the subacute exposure. ABPP analysis revealed that FAAH was selectively inhibited among the FNT-treated testicular membrane proteome. Accordingly, FAAH is a potential target for OP-elicited spermatotoxicity.

Cantor-type cylindrical-coordinate method for differential equations with local fractional derivatives

International Nuclear Information System (INIS)

Yang, Xiao-Jun; Srivastava, H.M.; He, Ji-Huan; Baleanu, Dumitru

2013-01-01

In this Letter, we propose to use the Cantor-type cylindrical-coordinate method in order to investigate a family of local fractional differential operators on Cantor sets. Some testing examples are given to illustrate the capability of the proposed method for the heat-conduction equation on a Cantor set and the damped wave equation in fractal strings. It is seen to be a powerful tool to convert differential equations on Cantor sets from Cantorian-coordinate systems to Cantor-type cylindrical-coordinate systems.

Dynamic shear-bending buckling experiments of cylindrical shells

International Nuclear Information System (INIS)

Hagiwara, Y.; Akiyama, H.

1995-01-01

Dynamic experimental studies of the plastic shear/bending buckling of cylindrical shells were performed. They clarified the inelastic response reduction and the seismic margin of FBR reactor vessels. The test results were incorporated into the draft of the seismic buckling design guidelines of FBR. (author). 15 refs., 3 figs

Noninvasive photoacoustic measurement of absorption coefficient using internal light irradiation of cylindrical diffusing fiber

Science.gov (United States)

Peng, Dong-qing; Zhu, Li-li; Li, Zhi-fang; Li, Hui

2017-09-01

Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber (CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.

Overflow Characteristic of Cylindrical Shape Crest Weirs Over Horizontal Bed

Directory of Open Access Journals (Sweden)

Emad4 AbdulGabbar

2013-05-01

Full Text Available The most common types of weirs are the broad-crested weir, the sharp-crested weir, the circular crested weir and the ogee crested weir. Advantages of the cylindrical weir shape include the stable overflow pattern, the ease to pass floating debris, the simplicity of design compared to ogee crest design and the associated lower costs. In present study, it was investigated the overflow characteristics of circular weirs in laboratory for various cylinder radii of three sizes (11.4, 9.0, 6.3 cm, and the models fixed on the channel bed vertically to the direction of flow. The result shows that the increase in the ratio of head to weir radius ratio (Hw/R value causes an increase in discharge coefficient (Cd value for the same height of weir. It was observed that the cylinder size (i.e. radius of cylindrical weir (R has an effect on the (Cd. The flow magnification factor (qw/qs increases with an increase in (Hw/R value and values of (qw/qs were always higher than one for all values of (Hw/R, this means that weirs of cylindrical shape performed better than those of sharp crest for any value of weir radius tested in this study.

TUNNEL POINT CLOUD FILTERING METHOD BASED ON ELLIPTIC CYLINDRICAL MODEL

Directory of Open Access Journals (Sweden)

N. Zhu

2016-06-01

Full Text Available The large number of bolts and screws that attached to the subway shield ring plates, along with the great amount of accessories of metal stents and electrical equipments mounted on the tunnel walls, make the laser point cloud data include lots of non-tunnel section points (hereinafter referred to as non-points, therefore affecting the accuracy for modeling and deformation monitoring. This paper proposed a filtering method for the point cloud based on the elliptic cylindrical model. The original laser point cloud data was firstly projected onto a horizontal plane, and a searching algorithm was given to extract the edging points of both sides, which were used further to fit the tunnel central axis. Along the axis the point cloud was segmented regionally, and then fitted as smooth elliptic cylindrical surface by means of iteration. This processing enabled the automatic filtering of those inner wall non-points. Experiments of two groups showed coincident results, that the elliptic cylindrical model based method could effectively filter out the non-points, and meet the accuracy requirements for subway deformation monitoring. The method provides a new mode for the periodic monitoring of tunnel sections all-around deformation in subways routine operation and maintenance.

Continuing investigations for technology assessment of 99Mo production from LEU [low enriched Uranium] targets

International Nuclear Information System (INIS)

Vandergrift, G.F.; Kwok, J.D.; Marshall, S.L.; Vissers, D.R.; Matos, J.E.

1987-01-01

Currently much of the world's supply of /sup 99m/Tc for medical purposes is produced from 99 Mo derived from the fissioning of high enriched uranium (HEU). The need for /sup 99m/Tc is continuing to grow, especially in developing countries, where needs and national priorities call for internal production of 99 Mo. This paper presents the results of our continuing studies on the effects of substituting low enriched Uranium (LEU) for HEU in targets for the production of fission product 99 Mo. Improvements in the electrodeposition of thin films of uranium metal are reported. These improvements continue to increase the appeal for the substitution of LEU metal for HEU oxide films in cylindrical targets. The process is effective for targets fabricated from stainless steel or hastaloy. A cost estimate for setting up the necessary equipment to electrodeposit uranium metal on cylindrical targets is reported. Further investigations on the effect of LEU substitution on processing of these targets are also reported. Substitution of uranium silicides for the uranium-aluminum alloy or uranium aluminide dispersed fuel used in other current target designs will allow the substitution of LEU for HEU in these targets with equivalent 99 Mo-yield per target and no change in target geometries. However, this substitution will require modifications in current processing steps due to (1) the insolubility of uranium silicides in alkaline solutions and (2) the presence of significant quantities of silicate in solution. Results to date suggest that both concerns can be handled and that substitution of LEU for HEU can be achieved

Induced charge electrophoresis of a conducting cylinder in a nonconducting cylindrical pore and its micromotoring application

Science.gov (United States)

Feng, Huicheng; Wong, Teck Neng; Che, Zhizhao

2016-08-01

Induced charge electrophoresis of a conducting cylinder suspended in a nonconducting cylindrical pore is theoretically analyzed and a micromotor is proposed that utilizes the cylinder rotation. The cylinder velocities are analytically obtained in the Dirichlet and the Neumann boundary conditions of the electric field on the cylindrical pore. The results show that the cylinder not only translates but also rotates when it is eccentric with respect to the cylindrical pore. The influences of a number of parameters on the cylinder velocities are characterized in detail. The cylinder trajectories show that the cylinder approaches and becomes stationary at certain positions within the cylindrical pore. The proposed micromotor is capable of working under a heavy load with a high rotational velocity when the eccentricity is large and the applied electric field is strong.

Effects of free-stream turbulence intensity and blowing ratio on film cooling of turbine blade leading edge

International Nuclear Information System (INIS)

Kim, S. M.; Kim, Youn J.; Cho, H. H.

2001-01-01

We used a cylindrical model which simulates turbine blade leading edge to investigate the effects of free-stream turbulence intensity and blowing ratio on film cooling of turbine blade leading edge. Tests are carried out in a low-speed wind tunnel on a cylindrical model with three rows of injection holes. Mainstream Reynolds number based on the cylinder diameter was 7.1x10 4 . Two types of turbulence grid are used to increase a free-stream turbulence intensity. The effect of coolant blowing ratio was studied for various blowing ratios. For each blowing ratios, wall temperatures around the surface of the test model are measured by thermocouples installed inside the model. Results show that blowing ratios have small effect on spanwise-averaged film effectiveness at high free-stream turbulence intensity. However, an increase in free-stream turbulence intensity enhances significantly spanwise-averaged film effectiveness at low blowing ratio

Next-to leading order analysis of target mass corrections to structure functions and asymmetries

International Nuclear Information System (INIS)

Brady, L.T.; Accardi, A.; Hobbs, T.J.; Melnitchouk, W.

2011-01-01

We perform a comprehensive analysis of target mass corrections (TMCs) to spin-averaged structure functions and asymmetries at next-to-leading order. Several different prescriptions for TMCs are considered, including the operator product expansion, and various approximations to it, collinear factorization, and xi-scaling. We assess the impact of each of these on a number of observables, such as the neutron to proton F 2 structure function ratio, and parity-violating electron scattering asymmetries for protons and deuterons which are sensitive to gamma-Z interference effects. The corrections from higher order radiative and nuclear effects on the parity-violating deuteron asymmetry are also quantified.

Theory of precipitation effects on dead cylindrical fuels

Science.gov (United States)

Michael A. Fosberg

1972-01-01

Numerical and analytical solutions of the Fickian diffusion equation were used to determine the effects of precipitation on dead cylindrical forest fuels. The analytical solution provided a physical framework. The numerical solutions were then used to refine the analytical solution through a similarity argument. The theoretical solutions predicted realistic rates of...

Linear acoustic waves induced in a cylindrical solid target by particle beam in e--e+ colliders

International Nuclear Information System (INIS)

Adeyemi, Olufemi Segun

2015-06-01

A future high energy lepton collider will demand high luminosities to achieve its physics goals. For the electron-positron linear collider, the generation of the desired amount of positrons is a non-trivial problem: the positron production target has to survive huge amounts of energy deposited by the bombardment of intense beams of electrons or photons. This causes a rapid increase of the temperature in the target within a very short time period. The resulting deformation due to the induced pressure waves can substantially shorten the operating life-span of the target material. In this work, we study linear effects of induced stress in a solid target through pressure acoustic waves using continuum mechanics. We derived analytical solutions for different cases and imposed different boundary conditions. The application of the model to the SLC positron target gave us the results which are in agreement with the existing literature. In a similar manner, we investigated the effect of single and multiple photon bunches on the conversion target for ILC.

Shaping of parabolic cylindrical membrane reflectors for the Dart Precision Test Bed

Science.gov (United States)

Morgan, R.; Agnes, Gregory S.; Dragovan, M.; Barber, D.; Marcin, M.; White, C.; Dooley, J.; Hatheway, A.

2004-01-01

The DART is a new telescope architecture consisting of a single aperture formed from two cylindrical parabolic reflectors. The system is ideally suited to using tensioned membranes for the reflective surfaces, owing to the zero Gaussian curvature of a cylindrical parabola. In this paper, we present experimental measurements for shaping the membranes by using curved boundary elements to achieve coarse shaping, and a pair of precision rails shaped by moments and forces at the ends, and lightly pushed into the surface, to provide fine shape control.

Exact relativistic cylindrical solution of disordered radiation

International Nuclear Information System (INIS)

Fonseca Teixeira, A.F. da; Wolk, I.; Som, M.M.

1976-05-01

A source free disordered distribution of electromagnetic radiation is considered in Einstein' theory, and a time independent exact solution with cylindrical symmetry is obtained. The gravitation and pressure effects of the radiation alone are sufficient to give the distribution an equilibrium. A finite maximum concentration is found on the axis of symmetry, and decreases monotonically to zero outwards. Timelike and null geodesics are discussed

Energy cost of negative pion production on deuterium-tritium target

Energy Technology Data Exchange (ETDEWEB)

Kuzminov, V.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Petrov, Yu.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Shabelski, Yu.M. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation))

1993-12-01

The negative pion production by deuterons (T[sub 0] = 0.8 GeV/nucl.) was calculated for a cylindrical gaseous deuterium-tritium target (the density of DT-mixture is [phi] = 0.5). Revised cross sections of nucleon-nucleus interaction were used in a Monte Carlo simulation and multiple nucleon-nuclei collisions were taken into account. The energy cost of negative pion production is [epsilon][sub [pi][sup -

Numerical Research on Flow Characteristics around a Hydraulic Turbine Runner at Small Opening of Cylindrical Valve

Directory of Open Access Journals (Sweden)

Zhenwei Mo

2016-01-01

Full Text Available We use the continuity equation and the Reynolds averaged Navier-Stokes equations to study the flow-pattern characteristics around a turbine runner for the small-opening cylindrical valve of a hydraulic turbine. For closure, we adopt the renormalization-group k-ε two-equation turbulence model and use the computational fluid dynamics (CFD software FLUENT to numerically simulate the three-dimensional unsteady turbulent flow through the entire passage of the hydraulic turbine. The results show that a low-pressure zone develops around the runner blades when the cylindrical valve is closed in a small opening; cavitation occurs at the blades, and a vortex appears at the outlet of the runner. As the cylindrical valve is gradually closed, the flow velocity over the runner area increases, and the pressure gradient becomes more significant as the discharge decreases. In addition, the fluid flow velocity is relatively high between the lower end of the cylindrical valve and the base, so that a high-velocity jet is easily induced. The calculation and analysis provide a theoretical basis for improving the performance of cylindrical-valve operating systems.

Secondary extinction in cylindrical and spherical crystals for X-ray and neutron diffraction

International Nuclear Information System (INIS)

Hu Huachen; Li Zhaohuan; Yang Bin; Shen Caiwan

2001-01-01

The distribution of the reflection power ratio for a neutron or x-ray diffracted from a cylindrical crystal immersed in an homogenous incident beam is obtained by the numerical solution of the transfer equations for the first time. The profile well reflects all the physical properties of the absorption and extinction behaviour in the crystals. A systematic investigation of the secondary extinction for cylindrical and spherical crystals was carried out based on these results

Development of position measurement unit for flying inertial fusion energy target

International Nuclear Information System (INIS)

Tsuji, R; Endo, T; Yoshida, H; Norimatsu, T

2016-01-01

We have reported the present status in the development of a position measurement unit (PMU) for a flying inertial fusion energy (IFE) target. The PMU, which uses Arago spot phenomena, is designed to have a measurement accuracy smaller than 1 μm. By employing divergent, pulsed orthogonal laser beam illumination, we can measure the time and the target position at the pulsed illumination. The two-dimensional Arago spot image is compressed into one-dimensional image by a cylindrical lens for real-time processing. The PMU are set along the injection path of the flying target. The local positions of the target in each PMU are transferred to the controller and analysed to calculate the target trajectory. Two methods are presented to calculate the arrival time and the arrival position of the target at the reactor centre. (paper)

Development of position measurement unit for flying inertial fusion energy target

Science.gov (United States)

Tsuji, R.; Endo, T.; Yoshida, H.; Norimatsu, T.

2016-03-01

We have reported the present status in the development of a position measurement unit (PMU) for a flying inertial fusion energy (IFE) target. The PMU, which uses Arago spot phenomena, is designed to have a measurement accuracy smaller than 1 μm. By employing divergent, pulsed orthogonal laser beam illumination, we can measure the time and the target position at the pulsed illumination. The two-dimensional Arago spot image is compressed into one-dimensional image by a cylindrical lens for real-time processing. The PMU are set along the injection path of the flying target. The local positions of the target in each PMU are transferred to the controller and analysed to calculate the target trajectory. Two methods are presented to calculate the arrival time and the arrival position of the target at the reactor centre.

Development of a PVD-based manufacturing process of monolithic LEU irradiation targets for {sup 99}Mo production

Energy Technology Data Exchange (ETDEWEB)

Hollmer, Tobias

2015-08-03

{sup 99}Mo is the most important radioisotope in nuclear medicine. It is produced by fission of uranium in irradiation targets. The usage of cylindrical monolithic targets can ensure a safe supply of {sup 99}Mo and at the same reduce the amount of highly radioactive waste generated during production. To manufacture these targets, a novel PVD-based technique was developed. Both the feasibility and the high efficiency of this process were demonstrated in a prototype apparatus.

Modeling dose-rate on/over the surface of cylindrical radio-models using Monte Carlo methods

International Nuclear Information System (INIS)

Xiao Xuefu; Ma Guoxue; Wen Fuping; Wang Zhongqi; Wang Chaohui; Zhang Jiyun; Huang Qingbo; Zhang Jiaqiu; Wang Xinxing; Wang Jun

2004-01-01

Objective: To determine the dose-rates on/over the surface of 10 cylindrical radio-models, which belong to the Metrology Station of Radio-Geological Survey of CNNC. Methods: The dose-rates on/over the surface of 10 cylindrical radio-models were modeled using the famous Monte Carlo code-MCNP. The dose-rates on/over the surface of 10 cylindrical radio-models were measured by a high gas pressurized ionization chamber dose-rate meter, respectively. The values of dose-rate modeled using MCNP code were compared with those obtained by authors in the present experimental measurement, and with those obtained by other workers previously. Some factors causing the discrepancy between the data obtained by authors using MCNP code and the data obtained using other methods are discussed in this paper. Results: The data of dose-rates on/over the surface of 10 cylindrical radio-models, obtained using MCNP code, were in good agreement with those obtained by other workers using the theoretical method. They were within the discrepancy of ±5% in general, and the maximum discrepancy was less than 10%. Conclusions: As if each factor needed for the Monte Carlo code is correct, the dose-rates on/over the surface of cylindrical radio-models modeled using the Monte Carlo code are correct with an uncertainty of 3%

Positive column of the discharge in a cylindrical shell

International Nuclear Information System (INIS)

Uehara, M.; Maciel, H.S.

1991-01-01

A Schottky type theoretical model is presented for the positive column of a discharge on a cylindric shell contained gas, with the discharge current flowing in the longitudinal direction. Some analytical results and the conclusion are presented. (L.C.J.A.). 5 refs

Cylindrical Taylor states conserving total absolute magnetic helicity

Science.gov (United States)

Low, B. C.; Fang, F.

2014-09-01

The Taylor state of a three-dimensional (3D) magnetic field in an upright cylindrical domain V is derived from first principles as an extremum of the total magnetic energy subject to a conserved, total absolute helicity Habs. This new helicity [Low, Phys. Plasmas 18, 052901 (2011)] is distinct from the well known classical total helicity and relative total helicity in common use to describe wholly-contained and anchored fields, respectively. A given field B, tangential along the cylindrical side of V, may be represented as a unique linear superposition of two flux systems, an axially extended system along V and a strictly transverse system carrying information on field-circulation. This specialized Chandrasekhar-Kendall representation defines Habs and permits a neat formulation of the boundary-value problem (BVP) for the Taylor state as a constant-α force-free field, treating 3D wholly-contained and anchored fields on the same conceptual basis. In this formulation, the governing equation is a scalar integro-partial differential equation (PDE). A family of series solutions for an anchored field is presented as an illustration of this class of BVPs. Past treatments of the constant-α field in 3D cylindrical geometry are based on a scalar Helmholtz PDE as the governing equation, with issues of inconsistency in the published field solutions discussed over time in the journal literature. The constant-α force-free equation reduces to a scalar Helmholtz PDE only as special cases of the 3D integro-PDE derived here. In contrast, the constant-α force-free equation and the scalar Helmholtz PDE are absolutely equivalent in the spherical domain as discussed in Appendix. This theoretical study is motivated by the investigation of the Sun's corona but the results are also relevant to laboratory plasmas.

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…

Microinstabilities in a radially contracting inhomogeneous cylindrical plasma slab

International Nuclear Information System (INIS)

Deutsch, R.; Kaeppeler, H.J.

1980-07-01

In order to study the development of microinstabilities in a collapsing cylindrical plasma sheath, corresponding to the situations in a z-pinch or a plasma focus, the dispersion relation for electromagnetic perturbations is derived with the aid of a newly established slab-model for an inhomogeneous, radially contracting plasma. In contrast to previously used slab-models, the orientation of the electric field is in direction of the cylinder axis and the azimuthal magnetic field is induced by the current flowing through the cylindrical plasma slab. The Vlasov equation is used together with the Krook collision term in order to include the influence of collisions. The results of this theory presented in this report will be used to calculate the growth of drift instabilities in the compression phase of a plasma focus, and shall serve as a basis for further development of a more general dispersion relation including runaway-effects. (orig.)

Enhanced Performance of Cylindrical Hall Thrusters

International Nuclear Information System (INIS)

Raitses, Y.; Smirnov, A.; Fisch, N.J.

2007-01-01

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

Designing cylindrical implosion experiments on NIF to study deceleration phase of Rayleigh-Taylor

Science.gov (United States)

Vazirani, N.; Kline, J. L.; Loomis, E.; Sauppe, J. P.; Palaniyappan, S.; Flippo, K.; Srinivasan, B.; Malka, E.; Bose, A.; Shvarts, D.

2017-10-01

The Rayleigh-Taylor (RT) hydrodynamic instability occurs when a lower density fluid pushes on a higher density fluid. This occurs in inertial confinement fusion (ICF) implosions at each of the capsule interfaces during the initial acceleration and the deceleration as it stagnates. The RT instabilities mix capsule material into the fusion fuel degrading the Deuterium-Tritium reactivity and ultimately play a key role in limiting target performance. While significant effort has focused on understanding RT at the outer capsule surface, little work has gone into understanding the inner surface RT instability growth during the deceleration phase. Direct measurements of the RT instability are difficult to make at high convergence in a spherical implosion. Here we present the design of a cylindrical implosion system for the National Ignition Facility for studying deceleration phase RT. We will discuss the experimental design, the estimated instability growth, and our outstanding concerns.

Power reactors and sub-critical blanket systems with lead and lead-bismuth as coolant and/or target material. Utilization and transmutation of actinides and long lived fission products

International Nuclear Information System (INIS)

2003-05-01

High level radioactive waste disposal is an issue of great importance in the discussion of the sustainability of nuclear power generation. The main contributors to the high radioactivity are the fission products and the minor actinides. The long lived fission products and minor actinides set severe demands on the arrangements for safe waste disposal. Fast reactors and accelerator driven systems (ADS) are under development in Member States to reduce the long term hazard of spent fuel and radioactive waste, taking advantage of their incineration and transmutation capability. Important R and D programmes are being undertaken in many Member States to substantiate this option and advance the basic knowledge in this innovative area of nuclear energy development. The conceptual design of the lead cooled fast reactor concept BREST-OD-300, as well as various other conceptual designs of lead/lead-bismuth cooled fast reactors have been developed to meet enhanced safety and non-proliferation requirements, aiming at both energy production and transmutation of nuclear waste. Some R and D studies indicate that the use of lead and lead-bismuth coolant has some advantages in comparison with existing sodium cooled fast reactor systems, e.g.: simplified design of fast reactor core and BOP, enhanced inherent safety, and easier radwaste management in related fuel cycles. Moreover, various ADS conceptual designs with lead and lead-bismuth as target material and coolant also have been pursued. The results to date are encouraging, indicating that the ADS has the potential to offer an option for meeting the challenges of the back end fuel cycle. During the last decade, there have been substantial advances in several countries with their own R and D programme in the fields of lead/lead-bismuth cooled critical and sub-critical concepts. coolant technology, and experimental validation. In this context, international exchange of information and experience, as well as international

Escape and transmission probabilities in cylindrical geometry

International Nuclear Information System (INIS)

Bjerke, M.A.

1980-01-01

An improved technique for the generation of escape and transmission probabilities in cylindrical geometry was applied to the existing resonance cross section processing code ROLAIDS. The algorithm of Hwang and Toppel, [ANL-FRA-TM-118] (with modifications) was employed. The probabilities generated were found to be as accurate as those given by the method previously applied in ROLAIDS, while requiring much less computer core storage and CPU time

Transmission of infrared radiation through cylindrical waveguides

International Nuclear Information System (INIS)

Nucara, A.; Dore, P.; Calvani, P.; Cannavo', D.; Marcelli, A.

1998-01-01

Measurement of the transmittance of infrared radiation (v -1 ) through cylindrical waveguides are presented and discussed. The experimental results are compared with numerical simulations, obtained through conventional ray tracing programs. Finally, it' estimated the transmittance of a waveguide in the case of an infrared synchrotron radiation source. Are applied the results to the case of the DAΦNE collider, where a synchrotron radiation beamline for the far infrared is under construction

The evaluation study of high performance gas target system

International Nuclear Information System (INIS)

Hur, Min Goo; Yang, Seung Dae; Kim, Sang Wook

2008-06-01

The object of this study is a improvement of a gas target and targetry for increasing the radioisotope production yields. The main results are as follows 1. Improvement of beam entrance of the gas target : In this work, deep hole grid was designed for improvement of beam entrance. Using FEM(Finite Elements Method) analysis, it was verified that this design is more effective than the old one. 2. Improvement of target gas loading and withdrawing system : For the targetry, Helium gas and vacuum lines was installed for evaluating the production yields. Using these lines, it was proved that the recovery yields was improved and the residual impurity was reduced. 3. Improvement of target cooling efficiency : In case of the cylindrical target, it is more effective to use short length of target cavity for the high production yields. For improving the cooling efficiency, cooling fin was suggested to the target design. It is more effective to put the cooling fins inside the target cavity for the suppressed target pressure and density reduction effect during the proton beam irradiation. In conclusion, the target with fins inside the target cavity was better for high current irradiation and mass RI production

The evaluation study of high performance gas target system

Energy Technology Data Exchange (ETDEWEB)

Hur, Min Goo; Yang, Seung Dae; Kim, Sang Wook

2008-06-15

The object of this study is a improvement of a gas target and targetry for increasing the radioisotope production yields. The main results are as follows 1. Improvement of beam entrance of the gas target : In this work, deep hole grid was designed for improvement of beam entrance. Using FEM(Finite Elements Method) analysis, it was verified that this design is more effective than the old one. 2. Improvement of target gas loading and withdrawing system : For the targetry, Helium gas and vacuum lines was installed for evaluating the production yields. Using these lines, it was proved that the recovery yields was improved and the residual impurity was reduced. 3. Improvement of target cooling efficiency : In case of the cylindrical target, it is more effective to use short length of target cavity for the high production yields. For improving the cooling efficiency, cooling fin was suggested to the target design. It is more effective to put the cooling fins inside the target cavity for the suppressed target pressure and density reduction effect during the proton beam irradiation. In conclusion, the target with fins inside the target cavity was better for high current irradiation and mass RI production.

Absorption factor for cylindrical samples

International Nuclear Information System (INIS)

Sears, V.F.

1984-01-01

The absorption factor for the scattering of X-rays or neutrons in cylindrical samples is calculated by numerical integration for the case in which the absorption coefficients of the incident and scattered beams are not equal. An extensive table of values having an absolute accuracy of 10 -4 is given in a companion report [Sears (1983). Atomic Energy of Canada Limited, Report No. AECL-8176]. In the present paper an asymptotic expression is derived for the absorption factor which can be used with an error of less than 10 -3 for most cases of interest in both neutron inelastic scattering and neutron diffraction in crystals. (Auth.)

Effective response of nonlinear cylindrical coated composites under external AC and DC electric field

International Nuclear Information System (INIS)

Yu-Yan, Shen; Xiao-Gang, Chen; Wei, Cui; Yan-Hua, Hao; Qian-Qian, Li

2009-01-01

This paper uses the perturbation method to study effective response of nonlinear cylindrical coated composites. Under the external AC and DC electric field E a (1 + sin ωt), the local potentials of composites at all harmonic frequencies are induced. An effective nonlinear response to composite is given for the cylindrical coated inclusions in the dilute limit. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Reduction of the radiating sound of a submerged finite cylindrical shell structure by active vibration control.

Science.gov (United States)

Kim, Heung Soo; Sohn, Jung Woo; Jeon, Juncheol; Choi, Seung-Bok

2013-02-06

In this work, active vibration control of an underwater cylindrical shell structure was investigated, to suppress structural vibration and structure-borne noise in water. Finite element modeling of the submerged cylindrical shell structure was developed, and experimentally evaluated. Modal reduction was conducted to obtain the reduced system equation for the active feedback control algorithm. Three Macro Fiber Composites (MFCs) were used as actuators and sensors. One MFC was used as an exciter. The optimum control algorithm was designed based on the reduced system equations. The active control performance was then evaluated using the lab scale underwater cylindrical shell structure. Structural vibration and structure-borne noise of the underwater cylindrical shell structure were reduced significantly by activating the optimal controller associated with the MFC actuators. The results provide that active vibration control of the underwater structure is a useful means to reduce structure-borne noise in water.

Reduction of the Radiating Sound of a Submerged Finite Cylindrical Shell Structure by Active Vibration Control

Directory of Open Access Journals (Sweden)

Seung-Bok Choi

2013-02-01

Full Text Available In this work, active vibration control of an underwater cylindrical shell structure was investigated, to suppress structural vibration and structure-borne noise in water. Finite element modeling of the submerged cylindrical shell structure was developed, and experimentally evaluated. Modal reduction was conducted to obtain the reduced system equation for the active feedback control algorithm. Three Macro Fiber Composites (MFCs were used as actuators and sensors. One MFC was used as an exciter. The optimum control algorithm was designed based on the reduced system equations. The active control performance was then evaluated using the lab scale underwater cylindrical shell structure. Structural vibration and structure-borne noise of the underwater cylindrical shell structure were reduced significantly by activating the optimal controller associated with the MFC actuators. The results provide that active vibration control of the underwater structure is a useful means to reduce structure-borne noise in water.

Prevalence and associations of anisometropia with spherical ametropia, cylindrical power, age, and sex in refractive surgery candidates.

Science.gov (United States)

Linke, Stephan J; Richard, Gisbert; Katz, Toam

2011-09-29

To analyze the prevalence and associations of anisometropia with spherical ametropia, astigmatism, age, and sex in a refractive surgery population. Medical records of 27,070 eyes of 13,535 refractive surgery candidates were reviewed. Anisometropia, defined as the absolute difference in mean spherical equivalent powers between right and left eyes, was analyzed for subjective (A(subj)) and cycloplegic refraction (A(cycl)). Correlations between anisometropia (>1 diopter) and spherical ametropia, cylindrical power, age, and sex, were analyzed using χ² and nonparametric Kruskal-Wallis or Mann-Whitney tests and binomial logistic regression analyses. Power vector analysis was applied for further analysis of cylindrical power. Prevalence of A(subj) was 18.5% and of A(cycl) was 19.3%. In hyperopes, logistic regression analysis revealed that only spherical refractive error (odds ratio [OR], 0.72) and age (OR, 0.97) were independently associated with anisometropia. A(subj) decreased with increasing spherical ametropia and advancing age. Cylindrical power and sex did not significantly affect A(subj). In myopes all explanatory variables (spherical power OR, 0.93; cylindrical power OR, 0.75; age OR, 1.02; sex OR, 0.8) were independently associated with anisometropia. Cylindrical power was most strongly associated with anisometropia. Advancing age and increasing spherical/cylindrical power correlated positively with increasing anisometropia in myopic subjects. Female sex was more closely associated with anisometropia. This large-scale retrospective analysis confirmed an independent association between anisometropia and both spherical ametropia and age in refractive surgery candidates. Notably, an inverse relationship between these parameters in hyperopes was observed. Cylindrical power and female sex were independently associated with anisometropia in myopes.

The nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores

International Nuclear Information System (INIS)

Yu-Lin, Feng; Xiao-Zhou, Liu; Jie-Hui, Liu; Li, Ma

2009-01-01

Based on an equivalent medium approach, this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores' nonlinear oscillations on sound attenuation, sound dispersion and an equivalent acoustic nonlinearity parameter are discussed. The calculated results show that the attenuation increases with an increasing volume fraction of micropores. The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores. Furthermore, multiple scattering has been taken into account, which leads to a modification to the effective wave number in the equivalent medium approach. We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%

Hydrogen isotope double differential production cross sections induced by 62.7 MeV neutrons on a lead target

International Nuclear Information System (INIS)

Kerveno, M.; Haddad, F.; Eudes, Ph.; Kirchner, T.; Lebrun, C.; Slypen, I.; Meulders, J.P.; Le Brun, C.; Lecolley, F.R.; Lecolley, J.F.; Louvel, M.; Lefebvres, F.; Hilaire, S.; Koning, A.J.

2002-01-01

Double differential hydrogen isotope production cross sections have been extracted in 62.7 MeV neutron induced reactions on a lead target. The angular distribution was measured at eight angles from 20 deg. to 160 deg. allowing the extraction of angle-differential, energy differential, and total production cross sections. A first set of comparisons with several theoretical calculations is also presented

Fermionic vacuum polarization by a cylindrical boundary in the cosmic string spacetime

International Nuclear Information System (INIS)

Bezerra de Mello, E. R.; Bezerra, V. B.; Saharian, A. A.; Tarloyan, A. S.

2008-01-01

The vacuum expectation values of the energy-momentum tensor and the fermionic condensate are analyzed for a massive spinor field obeying the MIT bag boundary condition on a cylindrical shell in the cosmic string spacetime. Both regions inside and outside the shell are considered. By applying to the corresponding mode sums a variant of the generalized Abel-Plana formula, we explicitly extract the parts in the expectation values corresponding to the cosmic string geometry without boundaries. In this way the renormalization procedure is reduced to that for the boundary-free cosmic string spacetime. The parts induced by the cylindrical shell are presented in terms of integrals rapidly convergent for points away from the boundary. The behavior of the vacuum densities is investigated in various asymptotic regions of the parameters. In the limit of large values of the planar angle deficit, the boundary-induced expectation values are exponentially suppressed. As a special case, we discuss the fermionic vacuum densities for the cylindrical shell on the background of the Minkowski spacetime.

A calculation model for primary intensity distributions from cylindrically symmetric x-ray lenses

International Nuclear Information System (INIS)

Hristov, Dimitre; Maltz, Jonathan

2008-01-01

A calculation model for the quantitative prediction of primary intensity fluence distributions obtained by the Bragg diffraction focusing of kilovoltage radiation by cylindrical x-ray lenses is presented. The mathematical formalism describes primary intensity distributions from cylindrically-symmetric x-ray lenses, with a planar isotropic radiation source located in a plane perpendicular to the lens axis. The presence of attenuating medium inserted between the lens and the lens focus is accounted for by energy-dependent attenuation. The influence of radiation scattered within the media is ignored. Intensity patterns are modeled under the assumption that photons that are not interacting with the lens are blocked out at any point of interest. The main characteristics of the proposed calculation procedure are that (i) the application of vector formalism allows universal treatment of all cylindrical lenses without the need of explicit geometric constructs; (ii) intensity distributions resulting from x-ray diffraction are described by a 3D generalization of the mosaic spread concept; (iii) the calculation model can be immediately coupled to x-ray diffraction simulation packages such as XOP and Shadow. Numerical simulations based on this model are to facilitate the design of focused orthovoltage treatment (FOT) systems employing cylindrical x-ray lenses, by providing insight about the influence of the x-ray source and lens parameters on quantities of dosimetric interest to radiation therapy

Coupled dilaton and electromagnetic field in cylindrically symmetric ...

Indian Academy of Sciences (India)

An exact solution is obtained for coupled dilaton and electromagnetic field in a cylindrically symmetric spacetime where an axial magnetic field as well as a radial electric field both are present. Depending on the choice of the arbitrary constants our solution reduces either to dilatonic gravity with pure electric field or to that ...

Simulation of cylindrical Pierce diodes with radial flow

International Nuclear Information System (INIS)

Alves, M.V.; Gnavi, G.; Gratton, F.T.; Buenos Aires Univ.

1996-01-01

In this paper we study the electron instability and the non linear behaviour of cylindrical Pierce's diodes by particle simulation. We ignore here the ion contribution (ions are fixed at a 1/r density and given a very large mass) to give perspicuity to the electron dynamics, and to facilitate comparison with existing theory. (author). 8 refs., 10 figs

Measurement of cylindrical particles with phase Doppler anemometry.

Science.gov (United States)

Mignon, H; Gréhan, G; Gouesbet, G; Xu, T H; Tropea, C

1996-09-01

Light scattering from cylindrical particles has been described with geometric optics. The feasibility of determining the particle diameter with a planar phase Doppler anemometer has been examined by simulations and experiments. In particular, the influence of particle orientation on measurability and measurement accuracy has been investigated. Some recommendations for realizing a practical-measurement instrument have been presented.

First experimental evidence of hydrodynamic tunneling of ultra-relativistic protons in extended solid copper target at the CERN HiRadMat facility

Science.gov (United States)

Schmidt, R.; Blanco Sancho, J.; Burkart, F.; Grenier, D.; Wollmann, D.; Tahir, N. A.; Shutov, A.; Piriz, A. R.

2014-08-01

A novel experiment has been performed at the CERN HiRadMat test facility to study the impact of the 440 GeV proton beam generated by the Super Proton Synchrotron on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed that leads to significant lengthening of the projectile range, which confirms our previous theoretical predictions [N. A. Tahir et al., Phys. Rev. Spec. Top.-Accel. Beams 15, 051003 (2012)]. Simulation results show very good agreement with the experimental measurements. These results have very important implications on the machine protection design for powerful machines like the Large Hadron Collider (LHC), the future High Luminosity LHC, and the proposed huge 80 km circumference Future Circular Collider, which is currently being discussed at CERN. Another very interesting outcome of this work is that one may also study the field of High Energy Density Physics at this test facility.

First experimental evidence of hydrodynamic tunneling of ultra–relativistic protons in extended solid copper target at the CERN HiRadMat facility

CERN Document Server

Schmidt, R; Sancho, J Blanco; Burkart, F; Grenier, D; Wollmann, D; Tahir, N A; Shutov, A; Piriz, A R

2014-01-01

A novel experiment has been performed at the CERN HiRadMat test facility to study the impact of the 440 GeV proton beam generated by the Super Proton Synchrotron on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed that leads to significant lengthening of the projectile range, which confirms our previous theoretical predictions [N. A. Tahir et al., Phys. Rev. Spec. Top.-Accel. Beams 15, 051003 (2012)]. Simulation results show very good agreement with the experimental measurements. These results have very important implications on the machine protection design for powerful machines like the Large Hadron Collider (LHC), the future High Luminosity LHC, and the proposed huge 80 km circumference Future Circular Collider, which is currently being discussed at CERN. Another very interesting outcome of this work is that one may also study the field of High Energy Density Physics at this test facility.

Influence of different moderator materials on characteristics of neutron fluxes generated under irradiation of lead target with proton beams

International Nuclear Information System (INIS)

Sosnin, A.N.; Polanski, A.; Petrochenkov, S.A.

2002-01-01

Neutron fields generated in extended heavy (Z ≥ 82) targets under irradiation with proton beams at energies in the range of 1 GeV are investigated. Influence of different moderators on the spectra and multiplicities of neutrons escaping the surface of the assembly consisting of a lead target (diam. 8 cm x 20 cm or diam. 8 cm x 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared. It is shown that the effectiveness of graphite as a material used in such assemblies to moderate spallation neutrons down to thermal energies is significantly lower than that of paraffin

Improvements of High Current/ Low Pressure Liquid And Gas Targets For Cyclotron Produced Radioisotopes

Energy Technology Data Exchange (ETDEWEB)

Hur, M. G. [Korea Atomic Energy Research Institute, Jeongup (Korea, Republic of); Hong, B. H. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chai, J. S. [SungKyunKwan University, Seoul (Korea, Republic of)

2009-07-01

The development of the C-11 cylindrical target with cooling fin for 13 MeV and 30 MeV proton beams and the development of pleated double-foil O-18 water target were carried out. For the test of new target system it was done at 2 pilots of cyclotron centres in Korea. The development of pleated double-foil O-18 water target was also executed. The pleated foil has the more advantages than flat foil. With the same beam bombarding the pleated foil with cooling had more yield of F-18production. CFD and FEM study were considered to design of the pleated foil and flat foil structure. (author)

Numerical Study on the Tensile Behavior of 3D Four Directional Cylindrical Braided Composite Shafts

Science.gov (United States)

Zhao, Guoqi; Wang, Jiayi; Hao, Wenfeng; Liu, Yinghua; Luo, Ying

2017-10-01

The tensile behavior of 3D four directional cylindrical braided composite shafts was analyzed with the numerical method. The unit cell models for the 3D four directional cylindrical braided composite shafts with various braiding angles were constructed with ABAQUS. Hashin's failure criterion was used to analyze the tensile strength and the damage evolution of the unit cells. The influence of the braiding angle on the tensile behavior of the 3D four directional cylindrical braided composite shafts was analyzed. The numerical results showed that the tensile strength along the braiding direction increased as the braiding angle decreased. These results should play an integral role in the design of braiding composites shafts.

A study of aerosol deposition by thermophoresis in cylindrical ducts

International Nuclear Information System (INIS)

Montassier, N.

1990-01-01

The scope of the study was aerosol deposition in cylindrical ducts, and the deposition due to thermophoresis particularly. The theoretical knowledge on this force and the basis of fluid mechanics are first recalled. An experimental study of thermophoretic deposition of particles in laminar flow was carried out in the particular case of uniform particle concentration and gas temperature at the inlet of the cooled tube. When the gas temperature was equilibrated with the wall temperature and thermophoretic particle deposition along the walls had ceased, the deposition efficiency approached a limit. Our experimental results showed that this limiting efficiency was independent on flow. Finally, for the laminar flow regime, a set of simple equations was developed in order to forecast the thermophoretic deposition of particles of any size along a cylindrical tube [fr

Two-point method uncertainty during control and measurement of cylindrical element diameters

Science.gov (United States)

Glukhov, V. I.; Shalay, V. V.; Radev, H.

2018-04-01

The topic of the article is devoted to the urgent problem of the reliability of technical products geometric specifications measurements. The purpose of the article is to improve the quality of parts linear sizes control by the two-point measurement method. The article task is to investigate methodical extended uncertainties in measuring cylindrical element linear sizes. The investigation method is a geometric modeling of the element surfaces shape and location deviations in a rectangular coordinate system. The studies were carried out for elements of various service use, taking into account their informativeness, corresponding to the kinematic pairs classes in theoretical mechanics and the number of constrained degrees of freedom in the datum element function. Cylindrical elements with informativity of 4, 2, 1 and θ (zero) were investigated. The uncertainties estimation of in two-point measurements was made by comparing the results of of linear dimensions measurements with the functional diameters maximum and minimum of the element material. Methodical uncertainty is formed when cylindrical elements with maximum informativeness have shape deviations of the cut and the curvature types. Methodical uncertainty is formed by measuring the element average size for all types of shape deviations. The two-point measurement method cannot take into account the location deviations of a dimensional element, so its use for elements with informativeness less than the maximum creates unacceptable methodical uncertainties in measurements of the maximum, minimum and medium linear dimensions. Similar methodical uncertainties also exist in the arbitration control of the linear dimensions of the cylindrical elements by limiting two-point gauges.

Analysis of Hall Probe Precise Positioning with Cylindrical Permanent Magnet

International Nuclear Information System (INIS)

Belicev, P.; Vorozhtsov, A.S.; Vorozhtsov, S.B.

2007-01-01

Precise positioning of a Hall probe for cyclotron magnetic field mapping, using cylindrical permanent magnets, was analyzed. The necessary permanent magnet parameters in order to achieve ±20 μm position precision, were determined. (author)

Cylindrical ionization chamber with compressed krypton

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Viyar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Puimedon, J.; Saens, K.; Salinas, A.; Sarsa, M.

1993-01-01

A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78 Kr. 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 88 Y) when the chamber is filled with a mixture of Kr+0.2% H 2 under a pressure of 25 atm

History of the small cylindrical melter

International Nuclear Information System (INIS)

Allen, T.L.; Iverson, D.C.; Plodinec, M.J.

1985-08-01

The small cylindrical melter (SCM) was designed to provide engineering data useful for operation and design of full-scale glass melters for vitrification of high-level radioactive waste. This melter was part of the research and development program for the Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP). Extensive corrosion testing of melter materials of construction (Monofrax K3, Inconel 690), simulated radioactive waste glass characterization, and melter component development were conducted in support of the DWPF full-scale melter design. 66 figs., 14 tabs

Fast, inexpensive, diffraction limited cylindrical microlenses

International Nuclear Information System (INIS)

Synder, J.J.; Reichert, P.

1991-01-01

We have developed a technique for fabricating fast, well corrected cylindrical microlenses. With this technique we have made a number of different microlenses with dimensions and focal lengths in the range of few hundred μm, and diffraction limited numerical apertures as high as 0.9. The microlenses are specifically designed for applications where they can increase the radiance or otherwise enhance the optical characteristics of laser diode light. The fabrication method we use is very versatile, and the microlenses produced this way would be very inexpensive in production quantities. 6 refs., 4 figs

Examining the fragmentation of 158 A GeV lead ions on copper target: Charge-changing cross sections

International Nuclear Information System (INIS)

Rana, Mukhtar Ahmed; Manzoor, Shahid

2008-01-01

A stack of plastic CR-39 Track Detectors were exposed to 158 A GeV 207 Pb ions at the CERN-SPS beam facility. The exposure of stack was performed at normal incidence with a fluence of about 1500ions/cm 2 . The total number of lead ions in each spill was about 7.8x10 4 with eight spills on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 detectors (before and after the target) were measured. Using these measurements and charge identification methodology in CR-39 track detectors, total and partial charge changing cross sections of 158 A GeV Pb 82+ ions on Cu and CR-39 targets are determined in the charge region 63≤Z≤82. The possibilities of presence and absence of odd-even effect in measured partial charge changing cross sections of 158 A GeV Pb ions for Cu and CR-39 targets are described. The charge resolution (σ Z ) achieved in the present experiment is ∼0.18e-0.21e. The analysis of discrepancies between our experimental results and other published results for the identical reaction is also presented

Examining the fragmentation of 158 A GeV lead ions on copper target: Charge-changing cross sections

Energy Technology Data Exchange (ETDEWEB)

Rana, Mukhtar Ahmed [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)], E-mail: marana@alumni.nus.edu.sg; Manzoor, Shahid [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

2008-09-15

A stack of plastic CR-39 Track Detectors were exposed to 158 A GeV {sup 207}Pb ions at the CERN-SPS beam facility. The exposure of stack was performed at normal incidence with a fluence of about 1500ions/cm{sup 2}. The total number of lead ions in each spill was about 7.8x10{sup 4} with eight spills on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 detectors (before and after the target) were measured. Using these measurements and charge identification methodology in CR-39 track detectors, total and partial charge changing cross sections of 158 A GeV Pb{sup 82+} ions on Cu and CR-39 targets are determined in the charge region 63{<=}Z{<=}82. The possibilities of presence and absence of odd-even effect in measured partial charge changing cross sections of 158 A GeV Pb ions for Cu and CR-39 targets are described. The charge resolution ({sigma}{sub Z}) achieved in the present experiment is {approx}0.18e-0.21e. The analysis of discrepancies between our experimental results and other published results for the identical reaction is also presented.

A winning strategy for 3 x n Cylindrical Hex

DEFF Research Database (Denmark)

Huneke, S. C.; Hayward, R.; Toft, Bjarne

2014-01-01

For Cylindrical Hex on a board with circumference 3, we give a winning strategy for the end-to-end player. This is the first known winning strategy for odd circumference at least 3, answering a question of David Gale. (C) 2014 Elsevier B.V. All rights reserved....

Nonlinear finite element formulation for analyzing shape memory alloy cylindrical panels

International Nuclear Information System (INIS)

Mirzaeifar, R; Shakeri, M; Sadighi, M

2009-01-01

In this paper, a general incremental displacement based finite element formulation capable of modeling material nonlinearities based on first-order shear deformation theory (FSDT) is developed for cylindrical shape memory alloy (SMA) shells. The Boyd–Lagoudas phenomenological model with polynomial hardening in conjunction with 3D incremental convex cutting plane explicit algorithm is implemented for preparing the SMA constitutive model in the finite element formulation. Several numerical examples are presented for demonstrating the performance of the proposed formulation in stress, deflection and phase transformation analysis of pseudoelastic behavior of shape memory cylindrical panels with various boundary conditions. Also, it is shown that the presented formulation can be implemented for studying plates and beams with rectangular cross section

Inertial migrations of cylindrical particles in rectangular microchannels: Variations of equilibrium positions and equivalent diameters

Science.gov (United States)

Su, Jinghong; Chen, Xiaodong; Hu, Guoqing

2018-03-01

Inertial migration has emerged as an efficient tool for manipulating both biological and engineered particles that commonly exist with non-spherical shapes in microfluidic devices. There have been numerous studies on the inertial migration of spherical particles, whereas the non-spherical particles are still largely unexplored. Here, we conduct three-dimensional direct numerical simulations to study the inertial migration of rigid cylindrical particles in rectangular microchannels with different width/height ratios under the channel Reynolds numbers (Re) varying from 50 to 400. Cylindrical particles with different length/diameter ratios and blockage ratios are also concerned. Distributions of surface force with the change of rotation angle show that surface stresses acting on the particle end near the wall are the major contributors to the particle rotation. We obtain lift forces experienced by cylindrical particles at different lateral positions on cross sections of two types of microchannels at various Re. It is found that there are always four stable equilibrium positions on the cross section of a square channel, while the stable positions are two or four in a rectangular channel, depending on Re. By comparing the equilibrium positions of cylindrical particles and spherical particles, we demonstrate that the equivalent diameter of cylindrical particles monotonously increases with Re. Our work indicates the influence of a non-spherical shape on the inertial migration and can be useful for the precise manipulation of non-spherical particles.

Seismic behavior of a low-rise horizontal cylindrical tank

Science.gov (United States)

Fiore, Alessandra; Rago, Carlo; Vanzi, Ivo; Greco, Rita; Briseghella, Bruno

2018-05-01

Cylindrical storage tanks are widely used for various types of liquids, including hazardous contents, thus requiring suitable and careful design for seismic actions. The study herein presented deals with the dynamic analysis of a ground-based horizontal cylindrical tank containing butane and with its safety verification. The analyses are based on a detailed finite element (FE) model; a simplified one-degree-of-freedom idealization is also set up and used for verification of the FE results. Particular attention is paid to sloshing and asynchronous seismic input effects. Sloshing effects are investigated according to the current literature state of the art. An efficient methodology based on an "impulsive-convective" decomposition of the container-fluid motion is adopted for the calculation of the seismic force. The effects of asynchronous ground motion are studied by suitable pseudo-static analyses. Comparison between seismic action effects, obtained with and without consideration of sloshing and asynchronous seismic input, shows a rather important influence of these conditions on the final results.

Rayleigh-Taylor instability of cylindrical jets with radial motion

International Nuclear Information System (INIS)

Chen, X.M.; Schrock, V.E.; Peterson, P.F.

1997-01-01

Rayleigh-Taylor instability of an interface between fluids with different densities subjected to acceleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of instability for a cylindrical surface with radial motions. The results of the analysis show that, like the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed. (orig.)

Numerical solutions to critical problem of reflected cylindrical reactor

International Nuclear Information System (INIS)

Horie, Junnosuke

1977-01-01

The multi-region critical problem can be transformed into an eigenvalue problem in the classical sense by using the method of Kuscer and Corngold and of Wing. This transformation is applied to derive a variational formulation for a reflected reactor. An approximate critical value of the multiplying factor is determined by maximizing the Rayleigh quotient for radially and totally reflected cylindrical reactors. It is shown that this approximate critical value is an upper bound of the true critical value. From the facts that the operator is self-adjoint and the eigenfunction is positive, an expression is derived for the upper and lower bounds of the true eigenvalue, by making use of the approximate distribution. The difference of the upper and lower bounds is an uncertainty of the presumption of the true critical value. It is found that we can compute the bounds to any required precision. The narrow bounds are calculated for two radially and one totally reflected cylindrical reactors. (auth.)

Analysis of Experimental Research on Cyclones with Cylindrical and Spiral Shells

Directory of Open Access Journals (Sweden)

Aleksandras Chlebnikovas

2012-12-01

Full Text Available The conducted investigation is aimed at providing information on air flow parameters in the cylindrical and spiral shell (devices are designed for separating solid particles from air flow having tangent flow inlet. Experimental research has employed multi-cyclones created by the Department of Environmental Protection at Vilnius Gediminas Technical University. The study is focused on investigating and comparing the distribution of the dynamic pressure of the airflow in six-channel cyclones inside the structures of devices. The paper establishes and estimates the efficiency of air cleaning changing air phase parameters using different particulate matters. The efficiency of the cyclone has been defined applying the weighted method based on LAND 28-98/M-08 methodology. The article presents the results of experimental research on the air cleaning efficiency of cylindrical and spiral shells using 20 µm glass and clay particulate matter under the initial concentration that may vary from 500 mg/m3 to 15 g/m3 using semi-rings with windows at different positions. The obtained results has shown that the maximum efficiency of the cylindrical shell increases up to 87,3 % while the initial concentration of glass makes 15 g/m3.Article in Lithuanian

First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole

Directory of Open Access Journals (Sweden)

Wenyi Huo

2016-01-01

Full Text Available The octahedral spherical hohlraums have natural superiority in maintaining high radiation symmetry during the entire capsule implosion process in indirect drive inertial confinement fusion. While, in contrast to the cylindrical hohlraums, the narrow space between the laser beams and the spherical hohlraum wall is usually commented. In this Letter, we address this crucial issue and report our experimental work conducted on the SGIII-prototype laser facility which unambiguously demonstrates that a simple design of cylindrical laser entrance hole (LEH can dramatically improve the laser propagation inside the spherical hohlraums. In addition, the laser beam deflection in the hohlraum is observed for the first time in the experiments. Our 2-dimensional simulation results also verify qualitatively the advantages of the spherical hohlraums with cylindrical LEHs. Our results imply the prospect of adopting the cylindrical LEHs in future spherical ignition hohlraum design.

Rotating solitary wave at the wall of a cylindrical container

KAUST Repository

Amaouche, Mustapha; Ait Abderrahmane, Hamid; Vatistas, Georgios H.

2013-01-01

This paper deals with the theoretical modeling of a rotating solitary surface wave that was observed during water drainage from a cylindrical reservoir, when shallow water conditions were reached. It represents an improvement of our previous study

Radiation protection of staff in 111In radionuclide therapy--is the lead apron shielding effective?

Science.gov (United States)

Lyra, M; Charalambatou, P; Sotiropoulos, M; Diamantopoulos, S

2011-09-01

(111)In (Eγ = 171-245 keV, t1/2 = 2.83 d) is used for targeted therapies of endocrine tumours. An average activity of 6.3 GBq is injected into the liver by catheterisation of the hepatic artery. This procedure is time-consuming (4-5 min) and as a result, both the physicians and the technical staff involved are subjected to radiation exposure. In this research, the efficiency of the use of lead apron has been studied as far as the radiation protection of the working staff is concerned. A solution of (111)In in a cylindrical scattering phantom was used as a source. Close to the scattering phantom, an anthropomorphic male Alderson RANDO phantom was positioned. Thermoluminescent dosemeters were located in triplets on the front surface, in the exit and in various depths in the 26th slice of the RANDO phantom. The experiment was repeated by covering the RANDO phantom by a lead apron 0.25 mm Pb equivalent. The unshielded dose rates and the shielded photon dose rates were measured. Calculations of dose rates by Monte Carlo N-particle transport code were compared with this study's measurements. A significant reduction of 65 % on surface dose was observed when using lead apron. A decrease of 30 % in the mean absorbed dose among the different depths of the 26th slice of the RANDO phantom has also been noticed. An accurate correlation of the experimental results with Monte Carlo simulation has been achieved.

Radiation protection of staff in 111In radionuclide therapy-Is the lead apron shielding effective?

International Nuclear Information System (INIS)

Lyra, M.; Charalambatou, P.; Sotiropoulos, M.; Diamantopoulos, S.

2011-01-01

111 In (Eγ=171-245 keV, t1/2=2.83 d) is used for targeted therapies of endocrine tumours. An average activity of 6.3 GBq is injected into the liver by catheterisation of the hepatic artery. This procedure is time-consuming (4-5 min) and as a result, both the physicians and the technical staff involved are subjected to radiation exposure. In this research, the efficiency of the use of lead apron has been studied as far as the radiation protection of the working staff is concerned. A solution of 111 In in a cylindrical scattering phantom was used as a source. Close to the scattering phantom, an anthropomorphic male Alderson RANDO phantom was positioned. Thermoluminescent dosemeters were located in triplets on the front surface, in the exit and in various depths in the 26. slice of the RANDO phantom. The experiment was repeated by covering the RANDO phantom by a lead apron 0.25 mm Pb equivalent. The unshielded dose rates and the shielded photon dose rates were measured. Calculations of dose rates by Monte Carlo N-particle transport code were compared with this study's measurements. A significant reduction of 65 % on surface dose was observed when using lead apron. A decrease of 30 % in the mean absorbed dose among the different depths of the 26. slice of the RANDO phantom has also been noticed. An accurate correlation of the experimental results with Monte Carlo simulation has been achieved. (authors)

Bounds of thermal stability of infinite cylindrical structures with non-uniform internal heat generation

International Nuclear Information System (INIS)

Gadalla, M.A.

1992-01-01

This paper presents an overview analyses of the thermal instability or thermal viability of infinite cylindrical structures with non-linear and non-uniform internal heat generation. The structure may be subjected to different and combined boundary conditions. An analytical solution is obtained for the generalized problem in spite of the non-linearity and the non-homogeneity of the source term. Four case studies with different boundary conditions are presented. The analyses show that the critical parameter for thermal stability may be though of as an altitude of surface below which the cylindrical structure will be thermally stable and performance worthy. The results also show that the bounds of thermal stability of a cylindrical structure system (solid or hollow) is eminently determined by the boundary conditions to which the system is subjected and can significantly alter the life-span of the structure

Magnetoresistance of cylindrical nanowires with artificial pinning site

KAUST Repository

Vidal, Enrique Vilanova; Mohammed, H.; Ivanov, I.; Kosel, Jü rgen

2015-01-01

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].

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].

Thermal modeling of cylindrical lithium ion battery during discharge cycle

International Nuclear Information System (INIS)

Jeon, Dong Hyup; Baek, Seung Man

2011-01-01

Highlights: → Transient and thermo-electric finite element analysis (FEA) of cylindrical lithium ion (Li-ion) battery was presented. → This model provides the thermal behavior of Li-ion battery during discharge cycle. → A LiCoO 2 /C battery at various discharge rates was investigated. → The contribution of heat source due to joule heating was significant at a high discharge rate. → The contribution of heat source due to entropy change was dominant at a low discharge rate. - Abstract: Transient and thermo-electric finite element analysis (FEA) of cylindrical lithium ion (Li-ion) battery was presented. The simplified model by adopting a cylindrical coordinate was employed. This model provides the thermal behavior of Li-ion battery during discharge cycle. The mathematical model solves conservation of energy considering heat generations due to both joule heating and entropy change. A LiCoO 2 /C battery at various discharge rates was investigated. The temperature profile from simulation had similar tendency with experiment. The temperature profile was decomposed with contributions of each heat sources and was presented at several discharge rates. It was found that the contribution of heat source due to joule heating was significant at a high discharge rate, whereas that due to entropy change was dominant at a low discharge rate. Also the effect of cooling condition and the LiNiCoMnO 2 /C battery were analyzed for the purpose of temperature reduction.

Gamma ray absorption of cylindrical fissile material with dual shields

International Nuclear Information System (INIS)

Wu Chenyan; Cheng Yiying; Huang Yongyi; Lu Fuquan; Yang Fujia

2005-01-01

This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation perspectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solved the geometric information of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis. (authors)

Dynamics of cylindrical domain walls in smectic C liquid crystals

International Nuclear Information System (INIS)

Stewart, I W; Wigham, E J

2009-01-01

An analysis of the dynamics of cylindrical domain walls in planar aligned samples of smectic C liquid crystals is presented. A circular magnetic field, induced by an electric current, drives a time-dependent reorientation of the corresponding radially dependent director field. Nonlinear approximations to the relevant nonlinear dynamic equation, derived from smectic continuum theory, are solved in a comoving coordinated frame: exact solutions are found for a π-wall and numerical solutions are calculated for π/2-walls. Each calculation begins with an assumed initial state for the director that is a prescribed cylindrical domain wall. Such an initial wall will proceed to expand or contract as its central core propagates radially inwards or outwards, depending on the boundary conditions for the director, the elastic constants, the magnitude of the field and the sign of the magnetic anisotropy of the liquid crystal

Track reconstruction in the emulsion-lead target of the OPERA experiment using the ESS microscope

Science.gov (United States)

Arrabito, L.; Bozza, C.; Buontempo, S.; Consiglio, L.; Cozzi, M.; D'Ambrosio, N.; DeLellis, G.; DeSerio, M.; Di Capua, F.; Di Ferdinando, D.; Di Marco, N.; Ereditato, A.; Esposito, L. S.; Fini, R. A.; Giacomelli, G.; Giorgini, M.; Grella, G.; Ieva, M.; Janicsko Csathy, J.; Juget, F.; Kreslo, I.; Laktineh, I.; Manai, K.; Mandrioli, G.; Marotta, A.; Migliozzi, P.; Monacelli, P.; Moser, U.; Muciaccia, M. T.; Pastore, A.; Patrizii, L.; Petukhov, Y.; Pistillo, C.; Pozzato, M.; Romano, G.; Rosa, G.; Russo, A.; Savvinov, N.; Schembri, A.; Scotto Lavina, L.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Strolin, P.; Tioukov, V.; Waelchli, T.

2007-05-01

The OPERA experiment, designed to conclusively prove the existence of νμ→ντ oscillations in the atmospheric sector, makes use of a massive lead-nuclear emulsion target to observe the appearance of ντ's in the CNGS νμ beam. The location and analysis of the neutrino interactions in quasi real-time required the development of fast computer-controlled microscopes able to reconstruct particle tracks with sub-micron precision and high efficiency at a speed of ~20 cm2/h. This paper describes the performance in particle track reconstruction of the European Scanning System, a novel automatic microscope for the measurement of emulsion films developed for OPERA.

Track reconstruction in the emulsion-lead target of the OPERA experiment using the ESS microscope

International Nuclear Information System (INIS)

Arrabito, L; Bozza, C; Buontempo, S

2007-01-01

The OPERA experiment, designed to conclusively prove the existence of ν μ →ν τ oscillations in the atmospheric sector, makes use of a massive lead-nuclear emulsion target to observe the appearance of ν τ 's in the CNGS ν μ beam. The location and analysis of the neutrino interactions in quasi real-time required the development of fast computer-controlled microscopes able to reconstruct particle tracks with sub-micron precision and high efficiency at a speed of ∼20 cm 2 /h. This paper describes the performance in particle track reconstruction of the European Scanning System, a novel automatic microscope for the measurement of emulsion films developed for OPERA

The large cylindrical drift chamber of TASSO

International Nuclear Information System (INIS)

Boerner, H.; Fischer, H.M.; Hartmann, H.; Loehr, B.; Wollstadt, M.; Fohrmann, R.; Schmueser, P.; Cassel, D.G.; Koetz, U.; Kowalski, H.

1980-03-01

We have built and operated a large cylindrical drift chamber for the TASSO experiment at the DESY storage ring, PETRA. The chamber has a length of 3.5 m, a diameter of 2.5 m, and a total of 2340 drift cells. The cells are arranged in 15 concentric layers such that tracks can be reconstructed in three dimensions. A spatial resolution of 220 μm has been achieved for tracks of normal incidence on the drift cells. (orig.)

Influence of Different Moderator Materials on Characteristics of Neutron Fluxes Generated under Irradiation of Lead Target with Proton Beams

CERN Document Server

Sosnin, A N; Polanski, A; Petrochenkov, S A; Golovatyuk, V M; Krivopustov, M I; Bamblevski, V P; Westmeier, W; Odoj, R; Brandt, R; Robotham, H; Hashemi-Nezhad, S R; Zamani-Valassiadou, M

2002-01-01

Neutron fields generated in extended heavy (Z\\geq 82) targets under irradiation with proton beams at energies in the range of 1 GeV are investigated. Influence of different moderators on the spectra and multiplicities of neutrons escaping the surface of the assembly consisting of a lead target (\\varnothing 8 cm\\times 20 cm or \\varnothing 8cm\\times 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared in the present work. It is shown that the effectiveness of graphite as a material used in such assemblies to moderate spallation neutrons down to thermal energies is significantly lower than that of paraffin.

Linear simulations of the cylindrical Richtmyer-Meshkov instability in magnetohydrodynamics

KAUST Repository

Bakhsh, Abeer; Gao, Song; Samtaney, Ravi; Wheatley, V.

2016-01-01

fusion and suppression by means of a magnetic field, we investigate the RMI via linear MHD simulations in cylindrical geometry. The physical setup is that of a Chisnell-type converging shock interacting with a density interface with either axial

Development of a cylindrical gas-fired furnace for reycling ...

African Journals Online (AJOL)

This study presents the development of a cylindrical gas-fired furnace, which could be used for recycling aluminum in small-scale foundries in Nigeria. The crucible, combustion chamber, suspension shaft and bearings were appropriately sized. The furnace chamber was 410 mm high and 510 mm diameter and had a ...

Sensitivity study of buckling strength for cylindrical shells

Energy Technology Data Exchange (ETDEWEB)

Kato, Hideo; Sasaki, Toru [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Aiming at making clear buckling behavior of cylindrical shells under earthquake loadings, we investigated procedure of recent elastic-plastic buckling analysis by finite element method (FEM). Thereby it is confirmed that the buckling strength becomes as well as that of a shell with a cross section of a perfect cylinder, if we apply the first buckling eigenvector to imperfection mode and assume the maximum imperfection amplitude to be 1% of the wall thickness. And then, by carrying out sensitivity study of buckling with geometrical parameters, such as length (L), radius (R), wall thickness (t), and load parameter, such as pressure, we obtained several characteristics about buckling strength and buckling mode for cylindrical shells. From the geometrical parameter analysis, it is seen that bending buckling occurs for small R/t (thick wall) and elastic buckling occurs for 2{<=}L/R{<=}4 and R/t{>=}400. And from the load parameter analysis, it is shown that hoop stress caused by the inner pressure increases shear buckling strength but decreases bending buckling strength, and hoop stress by hydrostatic pressure changes buckling mode and generates local deformation. (author)

Sound-structure interaction analysis of an infinite-long cylindrical shell submerged in a quarter water domain and subject to a line-distributed harmonic excitation

Science.gov (United States)

Guo, Wenjie; Li, Tianyun; Zhu, Xiang; Miao, Yuyue

2018-05-01

The sound-structure coupling problem of a cylindrical shell submerged in a quarter water domain is studied. A semi-analytical method based on the double wave reflection method and the Graf's addition theorem is proposed to solve the vibration and acoustic radiation of an infinite cylindrical shell excited by an axially uniform harmonic line force, in which the acoustic boundary conditions consist of a free surface and a vertical rigid surface. The influences of the complex acoustic boundary conditions on the vibration and acoustic radiation of the cylindrical shell are discussed. It is found that the complex acoustic boundary has crucial influence on the vibration of the cylindrical shell when the cylindrical shell approaches the boundary, and the influence tends to vanish when the distances between the cylindrical shell and the boundaries exceed certain values. However, the influence of the complex acoustic boundary on the far-field sound pressure of the cylindrical shell cannot be ignored. The far-field acoustic directivity of the cylindrical shell varies with the distances between the cylindrical shell and the boundaries, besides the driving frequency. The work provides more understanding on the vibration and acoustic radiation behaviors of cylindrical shells with complex acoustic boundary conditions.

About local fractional three-dimensional compressible Navier-Stokes equations in Cantor-type cylindrical co-ordinate system

Directory of Open Access Journals (Sweden)

Gao Guo-Ping

2016-01-01

Full Text Available In this article, we investigate the local fractional 3-D compressible Navier-Stokes equation via local fractional derivative. We use the Cantor-type cylindrical co-ordinate method to transfer 3-D compressible Navier-Stokes equation from the Cantorian co-ordinate system to the Cantor-type cylindrical co-ordinate system.

Thermal neutron pulsed parameters in non-hydrogenous systems. Experiment for lead grains

International Nuclear Information System (INIS)

Drozdowicz, K.; Gabanska, B.; Kosik, M.; Krynicka, E.; Woznicka, U.; Zaleski, T.

1997-01-01

In Czubek's method of measurement of the thermal neutron macroscopic absorption cross section a two-region geometry is applied where the investigated sample is surrounded by an external moderator. Both regions in the measurements made up till now were hydrogenous, which means the same type of the thermal neutron transport properties. In the paper a theoretical consideration to use non-hydrogenous materials as the samples is presented. Pulsed neutron measurements have been performed on homogeneous material in a geometry of the classic experiment with the variable geometric buckling. Two decay constants have been measured for different cylindrical samples of small lead grains (a lead shot). (author)

Thermal radiation characteristics of nonisothermal cylindrical enclosures using a numerical ray tracing technique

Science.gov (United States)

Baumeister, Joseph F.

1990-01-01

Analysis of energy emitted from simple or complex cavity designs can lead to intricate solutions due to nonuniform radiosity and irradiation within a cavity. A numerical ray tracing technique was applied to simulate radiation propagating within and from various cavity designs. To obtain the energy balance relationships between isothermal and nonisothermal cavity surfaces and space, the computer code NEVADA was utilized for its statistical technique applied to numerical ray tracing. The analysis method was validated by comparing results with known theoretical and limiting solutions, and the electrical resistance network method. In general, for nonisothermal cavities the performance (apparent emissivity) is a function of cylinder length-to-diameter ratio, surface emissivity, and cylinder surface temperatures. The extent of nonisothermal conditions in a cylindrical cavity significantly affects the overall cavity performance. Results are presented over a wide range of parametric variables for use as a possible design reference.

Modeling of cylindrical surrounding gate MOSFETs including the fringing field effects

International Nuclear Information System (INIS)

Gupta, Santosh K.; Baishya, Srimanta

2013-01-01

A physically based analytical model for surface potential and threshold voltage including the fringing gate capacitances in cylindrical surround gate (CSG) MOSFETs has been developed. Based on this a subthreshold drain current model has also been derived. This model first computes the charge induced in the drain/source region due to the fringing capacitances and considers an effective charge distribution in the cylindrically extended source/drain region for the development of a simple and compact model. The fringing gate capacitances taken into account are outer fringe capacitance, inner fringe capacitance, overlap capacitance, and sidewall capacitance. The model has been verified with the data extracted from 3D TCAD simulations of CSG MOSFETs and was found to be working satisfactorily. (semiconductor devices)

Effect of matrix cracking on the time delayed buckling of viscoelastic laminated circular cylindrical shells

Institute of Scientific and Technical Information of China (English)

PENG Fan; FU YiMing; CHEN YaoJun

2008-01-01

The effect of matrix cracking on the bifurcation creep buckling of viscoelastic laminated circular cylindrical shells is investigated. The viscoelastic behavior of laminas is modeled by Schapery's integral constitutive equation with growing ma-trix cracks. The values of damage variables are correlated to non-dimensional density of matrix cracks relying on the formulas from meso-mechanics approach, and the evolution equation predicting the growth rate of density of matrix cracks is assumed to follow a power type relation with transverse tensile stress. The gov-erning equations for pre-buckling creep deformation and bifurcation buckling of laminated circular cylindrical shells under axial compression are obtained on the basis of the Donnell type shallow shell theory and Karman-Donnell geometrically nonlinear relationship. Corresponding solution strategy is constructed by inte-grating finite-difference technique, trigonometric series expansion method and Taylor's numerical recursive scheme for convolution integration. The bifurcation creep buckling of symmetrically laminated glass-epoxy circular cylindrical shells with matrix creep cracking coupled are examined for various geometrical parame-ters and parameters of damage evolution as well as boundary conditions. The nu-merical results show that matrix creep cracking remarkably shortens the critic time of bifurcation buckling and reduces the durable critic loads, and its effects become weak and finally vanish with the increase of the ratio of radius to thickness in the case of short laminated circular cylindrical shells, also the influence of the matrix creep cracking is mainly dependent on the boundary conditions at two ends for moderately long circular cylindrical shells.

Effect of matrix cracking on the time delayed buckling of viscoelastic laminated circular cylindrical shells

Institute of Scientific and Technical Information of China (English)

2008-01-01

The effect of matrix cracking on the bifurcation creep buckling of viscoelastic laminated circular cylindrical shells is investigated.The viscoelastic behavior of laminas is modeled by Schapery’s integral constitutive equation with growing matrix cracks.The values of damage variables are correlated to non-dimensional density of matrix cracks relying on the formulas from mesomechanics approach,and the evolution equation predicting the growth rate of density of matrix cracks is assumed to follow a power type relation with transverse tensile stress.The governing equations for prebuckling creep deformation and bifurcation buckling of laminated circular cylindrical shells under axial compression are obtained on the basis of the Donnell type shallow shell theory and Kármán-Donnell geometrically nonlinear relationship.Corresponding solution strategy is constructed by integrating finite-difference technique,trigonometric series expansion method and Taylor’s numerical recursive scheme for convolution integration.The bifurcation creep buckling of symmetrically laminated glass-epoxy circular cylindrical shells with matrix creep cracking coupled are examined for various geometrical parameters and parameters of damage evolution as well as boundary conditions.The numerical results show that matrix creep cracking remarkably shortens the critic time of bifurcation buckling and reduces the durable critic loads,and its effects become weak and finally vanish with the increase of the ratio of radius to thickness in the case of short laminated circular cylindrical shells,also the influence of the matrix creep cracking is mainly dependent on the boundary conditions at two ends for moderately long circular cylindrical shells.

ELECTROMAGNETIC FIELDS IN CYLINDRICAL INDUCTION INDUCTOR SYSTEM WITH MASSIVE SHIELD

Directory of Open Access Journals (Sweden)

D. Piskun

2010-12-01

Full Text Available The processes in a cylindrical induction inductor system with a massive additional non-magnetic shield and a thin ferromagnetic sheet blank are considered and the formula for induced currents and the strength of excited fields have been obtained.

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...

Impact of continuing scaling on the device performance of 3D cylindrical junction-less charge trapping memory

International Nuclear Information System (INIS)

Li Xinkai; Huo Zongliang; Jin Lei; Jiang Dandan; Hong Peizhen; Xu Qiang; Tang Zhaoyun; Li Chunlong; Ye Tianchun

2015-01-01

This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as program/erase speed, vertical charge loss, and lateral charge migration under high temperature are intensively studied using the Sentaurus 3D device simulator. Although scaling of channel radius is beneficial for operation speed improvement, it leads to a retention challenge due to vertical leakage, especially enhanced charge loss through TPO. Scaling of gate length not only decreases the program/erase speed but also leads to worse lateral charge migration. Scaling of spacer length is critical for the interference of adjacent cells and should be carefully optimized according to specific cell operation conditions. The gate stack shape is also found to be an important factor affecting the lateral charge migration. Our results provide guidance for high density and high reliability 3D CTM integration. (paper)

Chaotic Dynamics of Cage Behavior in a High-Speed Cylindrical Roller Bearing

Directory of Open Access Journals (Sweden)

Long Chen

2016-01-01

Full Text Available This paper presents a mathematical model to investigate the nonlinear dynamic behavior of cage in high-speed cylindrical bearing. Variations of cage behavior due to varying cage eccentricity and cage guidance gap are observed. Hydrodynamic behavior in cage contacts is taken into consideration for a more realistic calculation of acting forces owing to high working speed. Analysis of real-time cage dynamic behavior on radial plane is carried out using chaos theory based on the theoretical and mathematical model established in the paper. The analytical results of this paper provide a solid foundation for designing and manufacturing of high-speed cylindrical roller bearing.

DETERMINATION AND OPTIMIZATION OF CYLINDRICAL GRINDING PROCESS PARAMETERS USING TAGUCHI METHOD AND REGRESSION ANALYSIS

OpenAIRE

M.Janardhan; Dr.A.Gopala Krishna

2011-01-01

Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. Metal removal rate and surface finish are the important out put responses in the production with respect to quantity and quality respectively. The Experiments are conducted on CNC cylindrical grinding machine with L9 Orthogonal array with input machining variables as work speed, feed rate and depth of cut. Empirical models are developed using design of experiments and response su...

Nonlinear Diamagnetic Stabilization of Double Tearing Modes in Cylindrical MHD Simulations

Science.gov (United States)

Abbott, Stephen; Germaschewski, Kai

2014-10-01

Double tearing modes (DTMs) may occur in reversed-shear tokamak configurations if two nearby rational surfaces couple and begin reconnecting. During the DTM's nonlinear evolution it can enter an ``explosive'' growth phase leading to complete reconnection, making it a possible driver for off-axis sawtooth crashes. Motivated by similarities between this behavior and that of the m = 1 kink-tearing mode in conventional tokamaks we investigate diamagnetic drifts as a possible DTM stabilization mechanism. We extend our previous linear studies of an m = 2 , n = 1 DTM in cylindrical geometry to the fully nonlinear regime using the MHD code MRC-3D. A pressure gradient similar to observed ITB profiles is used, together with Hall physics, to introduce ω* effects. We find the diamagnetic drifts can have a stabilizing effect on the nonlinear DTM through a combination of large scale differential rotation and mechanisms local to the reconnection layer. MRC-3D is an extended MHD code based on the libMRC computational framework. It supports nonuniform grids in curvilinear coordinates with parallel implicit and explicit time integration.

Observing of tree trunks and other cylindrical objects using GPR

Science.gov (United States)

Jezova, Jana; Lambot, Sebastien

2016-04-01

Trees are a part of our everyday life, hence it is important to prevent their collapse to protect people and urban infrastructures. It is also important to characterize tree wood properties for usages in construction. In order to investigate internal parts of tree trunks non-invasively, ground-penetrating radar (GPR), or in this case, ultra-wideband microwave radar as a general tool, appears to be a very promising technology. Nevertheless, tree trunk tomography using microwave radar is a complicated task due to the circular shape of the trunk and the very complex (heterogeneous and anisotropic) internal structures of the trunk. Microwave sensing of tree trunks is also complicated due to the electromagnetic properties of living wood, which strongly depend on water content, density and temperature of wood. The objective of this study is to describe tree trunk radar cross sections including specific features originating from the particular circumferential data acquisition geometry. In that respect, three experiments were performed: (1) numerical simulations using a finite-difference time-domain software, namely, gprMax 2D, (2) measurements on a simplified laboratory trunk model including plastic and cardboard pipes, sand and air, and (3) measurements over a real tree trunk. The analysis was further deepened by considering: (1) common zero-offset reflection imaging, (2) imaging with a planar perfect electrical conductor (PEC) at the opposite side of the trunk, and (3) imaging with a PEC arc at the opposite side of the trunk. Furthermore, the shape of the reflection curve of a cylindrical target was analytically derived based on the straight-ray propagation approximation. Subsequently, the total internal reflection (TIR) phenomenon occurring in cylindrical objects was observed and analytically described. Both the straight-ray reflection curve and TIR were well observed on the simulated and laboratory radar data. A comparison between all experiments and radar

An approximate solution for spherical and cylindrical piston problem

Indian Academy of Sciences (India)

the growth and decay of shock strengths for spherical and cylindrical pistons starting from a non-zero ... conditions at an appropriate level, a new theory of shock dynamics (NTSD) has been proposed (Ravindran and ..... sive, its packing density etc. which are not included in our mathematical formulation, it may explain the ...

Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

Energy Technology Data Exchange (ETDEWEB)

Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2009-10-15

Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

International Nuclear Information System (INIS)

Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok

2009-01-01

Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

A DYNA3D calculation for impact on a pipe target

International Nuclear Information System (INIS)

Neilson, A.J.

1983-11-01

This report describes experimental studies to examine the response of pipework, typical of that used in nuclear power plants, to the impact of missiles representing fragments of disintegrating machinery. The finite element code DYNA3D has been used to make a calculation for one experiment in which an instrumented target pipe was impacted by a cylindrical steel billet. Transient displacement of the missile and target as well as permanent deformations of the target pipe were well-predicted by the code. The code reproduced the main features of the experimental transient strain measurements with the timings of the various straining phases being calculated very closely. Detailed quantitative comparisons cannot be made because of the lack of appropriate facilities in the GRAPE post-processing code. (U.K.)

Using Rutherford Backscattering Spectroscopy to Characterize Targets for MTW

Science.gov (United States)

Brown, Gunnar; Stockler, Barak; Ward, Ryan; Freeman, Charlie; Padalino, Stephen; Stillman, Collin; Ivancic, Steven; Reagan, S. P.; Sangster, T. C.

2017-10-01

A study is underway to determine the composition and thickness of targets used at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) using Rutherford backscattering spectroscopy (RBS). In RBS, an ion beam is incident on a sample and the scattered ions are detected with a surface barrier detector. The resulting energy spectra of the scattered ions can be analyzed to determine important parameters of the target including elemental composition and thickness. Proton, helium and deuterium beams from the 1.7 MV Pelletron accelerator at SUNY Geneseo have been used to characterize several different targets for MTW, including CH and aluminum foils of varying thickness. RBS spectra were also obtained for a cylindrical iron buried-layer target with aluminum dopant which was mounted on a silicon carbide stalk. The computer program SIMNRA is used to analyze the spectra. This work was funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Uniformity of cylindrical imploding underwater shockwaves at very small radii

Science.gov (United States)

Yanuka, D.; Rososhek, A.; Bland, S. N.; Krasik, Ya. E.

2017-11-01

We compare the convergent shockwaves generated from underwater, cylindrical arrays of copper wire exploded by multiple kilo-ampere current pulses on nanosecond and microsecond scales. In both cases, the pulsed power devices used for the experiments had the same stored energy (˜500 J) and the wire mass was adjusted to optimize energy transfer to the shockwave. Laser backlit framing images of the shock front were achieved down to the radius of 30 μm. It was found that even in the case of initial azimuthal non-symmetry, the shock wave self-repairs in the final stages of its motion, leading to a highly uniform implosion. In both these and previous experiments, interference fringes have been observed in streak and framing images as the shockwave approached the axis. We have been able to accurately model the origin of the fringes, which is due to the propagation of the laser beam diffracting off the uniform converging shock front. The dynamics of the shockwave and its uniformity at small radii indicate that even with only 500 J stored energies, this technique should produce pressures above 1010 Pa on the axis, with temperatures and densities ideal for warm dense matter research.

Experimental transient natural convection heat transfer from a vertical cylindrical tank

International Nuclear Information System (INIS)

Fernandez-Seara, Jose; Uhia, Francisco J.; Alberto Dopazo, J.

2011-01-01

In this paper heat transfer experimental data is presented and compared to general correlations proposed in the literature for transient laminar free convection from a vertical cylindrical tank. The experimental data has been obtained from heating and cooling experiments carried out with a cylindrical full-scale hot water storage tank working under real operating conditions. The experimental device and the data acquisition system are described. The calculation procedures established to obtain the experimental values of the heat transfer coefficients, as well as the data reduction process, are detailed. The local convection and radiation heat transfer coefficients are obtained from different heating power conditions for local Rayleigh numbers within the range of 1x10 5 -3x10 8 . The great quantity of available experimental data allows a detailed analysis with a reliable empirical base. The experimental local convection heat transfer coefficients are correlated and compared to correlations proposed in open literature for engineering calculations. - Highlights: → Experimental data of transient local convection heat transfer coefficients from a cylindrical tank for heating and cooling processes is obtained. → The transient behaviour of the convection coefficients is dependent on temperature difference evolutions between the surface and the air. → The Nu.Ra -1/4 ratio decreases proportionally in (T s -T ∞ ) -0.9 . → A new correlation based on the semi-infinite region theory for laminar transient free convection is proposed.

Electron Cross-field Transport in a Miniaturized Cylindrical Hall Thruster

International Nuclear Information System (INIS)

Smirnov Artem; Raitses Yevgeny; Fisch Nathaniel J

2005-01-01

Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. The present paper gives a review of the experimental and numerical investigations of electron crossfield transport in the 2.6 cm miniaturized cylindrical Hall thruster (100 W power level). We show that, in order to explain the discharge current observed for the typical operating conditions, the electron anomalous collision frequency ν b has to be on the order of the Bohm value, ν B ∼ ω c /16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The optimal regimes of thruster operation at low background pressure (below 10 -5 Torr) in the vacuum tank appear to be different from those at higher pressure (∼ 10 -4 Torr)

Self-consistent equilibrium in a cylindrical, dissipative reverse field pinch

International Nuclear Information System (INIS)

Guo, S.C.; Paccagnella, R.

1994-01-01

One of the authors (C.L.S.) recently proposed a dissipative model to self-consistently solve the equilibrium problem in a free-boundary plasma column under cylindrical symmetry. In the present paper, on one hand the problem is strongly specialized to circular symmetry and to Ohm's and Fourier's laws without off-diagonal contributions; on the other hand, it is generalized by adding a dynamo effective electric field E d in Ohm's law, based on the standard turbulent model. This seems appropriate enough to study RFP equilibria, since it is well known that a stationary and cylindrically symmetric RFP is incompatible with a classical Ohm's law. Reasonably, only numerical solutions are expected to be accessible in general; but the further simplified problem with scalar and constant electric resistivity and constant dynamo coefficient α (E d =αB) can be solved analytically by elementary means. (author) 4 refs., 2 figs

Laser-Plasma Interactions in Drive Campaign targets on the National Ignition Facility

International Nuclear Information System (INIS)

Hinkel, D E; Callahan, D A; Moody, J D; Amendt, P A; Lasinski, B F; MacGowan, B J; Meeker, D; Michel, P A; Ralph, J; Rosen, M D; Ross, J S; Schneider, M B; Storm, E; Strozzi, D J; Williams, E A

2016-01-01

The Drive campaign [D A Callahan et al., this conference] on the National Ignition Facility (NIF) laser [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, R. Al-Ayat, Phys. Plasmas 16, 041006 (2009)] has the focused goal of understanding and optimizing the hohlraum for ignition. Both the temperature and symmetry of the radiation drive depend on laser and hohlraum characteristics. The drive temperature depends on the coupling of laser energy to the hohlraum, and the symmetry of the drive depends on beam-to-beam interactions that result in energy transfer [P. A. Michel, S. H. Glenzer, L. Divol, et al, Phys. Plasmas 17, 056305 (2010).] within the hohlraum. To this end, hohlraums are being fielded where shape (rugby vs. cylindrical hohlraums), gas fill composition (neopentane at room temperature vs. cryogenic helium), and gas fill density (increase of ∼ 150%) are independently changed. Cylindrical hohlraums with higher gas fill density show improved inner beam propagation, as should rugby hohlraums, because of the larger radius over the capsule (7 mm vs. 5.75 mm in a cylindrical hohlraum). Energy coupling improves in room temperature neopentane targets, as well as in hohlraums at higher gas fill density. In addition cross-beam energy transfer is being addressed directly by using targets that mock up one end of a hohlraum, but allow observation of the laser beam uniformity after energy transfer. Ideas such as splitting quads into “doublets” by re-pointing the right and left half of quads are also being pursued. LPI results of the Drive campaign will be summarized, and analyses of future directions presented. (paper)

Target injection methods for inertial fusion energy

International Nuclear Information System (INIS)

Petzoldt, R.W.; Moir, R.W.

1994-06-01

We have studied four methods to inject IFE targets: the gas gun, electrostatic accelerator, induction accelerator, and rail gun. We recommend a gas gun for indirect drive targets because they can support a gas pressure load on one end and can slide along the gun barrel without damage. With the gas gun, the amount of gas required for each target (about 10 to 100 mg) is acceptable; for other types of targets, a sabot would be necessary. A cam and poppet valve arrangement is recommended for gas flow control. An electrostatic accelerator is attractive for use with lightweight spherical direct drive targets. Since there is no physical contact between the target and the injector, there will be no wear of either component during the injection process. An induction accelerator has an advantage of no electrical contact between the target and the injector. Physical contact is not even necessary, so the wear should be minimal. It requires a cylindrical conductive target sleeve which is a substantial added mass. A rail gun is a simpler device than an electrostatic accelerator or induction accelerator. It requires electrical contact between the target and the rails and may have a significant wear rate. The wear in a vacuum could be reduced by use of a solid lubricant such as MoS 2 . The total required accuracy of target injection, tracking and beam pointing of ±0.4 mm appears achievable but will require development and experimental verification

Superconducting vortex dynamics in cylindrical Nb micro- and nanotubes

Energy Technology Data Exchange (ETDEWEB)

Fomin, Vladimir M. [Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden (Germany); Rezaev, Roman O. [Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden (Germany); Laboratory of Mathematical Physics, Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Schmidt, Oliver G. [Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, D-09107 Chemnitz (Germany)

2012-07-01

Advancements in fabrication of rolled-up micro- and nanotubes including superconductor layers (e.g., InGaAs/GaAs/Nb) open new ways for investigation of the vortex matter in superconductors with curved geometries. Geometry determines the dynamics of vortices in the presence of transport currents in open superconductor micro- and nanotubes subject to a magnetic field orthogonal to the axis. Vortices nucleate periodically at one edge of the tube, subsequently move along the tube under the action of the Lorentz force and denucleate at the opposite edge of the tube. Characteristic times of nonequilibrium vortex dynamics in an open tube are efficiently controlled by the tube radius. The magnetic field, at which the vortices begin to nucleate at the edge of the structure, is increased several times by rolling up a planar film in a tube. This effect is caused not only by a spatial dependence of the magnetic field component normal to the cylindrical surface, but also by correlations between the states of the superconducting order parameter in the opposite areas of the cylindrical surface.

Nonlinear Vibration and Mode Shapes of FG Cylindrical Shells

Directory of Open Access Journals (Sweden)

Saeed Mahmoudkhani

Full Text Available Abstract The nonlinear vibration and normal mode shapes of FG cylindrical shells are investigated using an efficient analytical method. The equations of motion of the shell are based on the Donnell’s non-linear shallow-shell, and the material is assumed to be gradually changed across the thickness according to the simple power law. The solution is provided by first discretizing the equations of motion using the multi-mode Galerkin’s method. The nonlinear normal mode of the system is then extracted using the invariant manifold approach and employed to decouple the discretized equations. The homotopy analysis method is finally used to determine the nonlinear frequency. Numerical results are presented for the backbone curves of FG cylindrical shells, nonlinear mode shapes and also the nonlinear invariant modal surfaces. The volume fraction index and the geometric properties of the shell are found to be effective on the type of nonlinear behavior and also the nonlinear mode shapes of the shell. The circumferential half-wave numbers of the nonlinear mode shapes are found to change with time especially in a thinner cylinder.

Determination of optimal geometry for cylindrical sources for gamma radiation measurements; Odredjivanje optimalne geometrije za mjerenje gama zracenja cilindrichnih izvora

Energy Technology Data Exchange (ETDEWEB)

Sinjeri, Lj; Kulisic, P [Elektra - Zagreb, Zagreb (Yugoslavia)

1990-07-01

Low radioactive sources were used for experimental determination of optimal dimensions for cylindrical source using coaxial Ge(Li) detector. Then, calculational procedure is used to find optimal dimensions of cylindrical source. The results from calculational procedure confirm with experimental results. In such way the verification of calculational procedure is done and it can be used for determination of optimal geometry for low radioactive cylindrical sources. (author)

Design, Development and Testing of a Semi Cylindrical Capacitive Sensor for Liquid Level Measurement

Directory of Open Access Journals (Sweden)

Sagarika PAL

2010-05-01

Full Text Available In the present paper a low cost noncontact semi cylindrical capacitive type liquid level sensor has been designed, developed and tested. The semi cylindrical capacitive sensor consisting of two thin semi cylindrical metal plates separated by a gap distance and mounted around a non conducting storage tank, has been used to measure the liquid level in the tank. The measured capacitance variation with variation of liquid level is linear and obtained in the nano farad range which again has been converted into voltage variation by using proper signal conditioning circuit. Since the sensor is noncontact type it can be used for both conducting and non conducting type of liquid contained within a non conducting tank. For converting the capacitance variation in to voltage variation a series R-L-C resonating circuit has been used instead of conventional bridge circuit. Experimental results confirm the satisfactory performance of the sensor for liquid level measurement.

Macromolecular shape and interactions in layer-by-layer assemblies within cylindrical nanopores.

Science.gov (United States)

Lazzara, Thomas D; Lau, K H Aaron; Knoll, Wolfgang; Janshoff, Andreas; Steinem, Claudia

2012-01-01

Layer-by-layer (LbL) deposition of polyelectrolytes and proteins within the cylindrical nanopores of anodic aluminum oxide (AAO) membranes was studied by optical waveguide spectroscopy (OWS). AAO has aligned cylindrical, nonintersecting pores with a defined pore diameter d(0) and functions as a planar optical waveguide so as to monitor, in situ, the LbL process by OWS. The LbL deposition of globular proteins, i.e., avidin and biotinylated bovine serum albumin was compared with that of linear polyelectrolytes (linear-PEs), both species being of similar molecular weight. LbL deposition within the cylindrical AAO geometry for different pore diameters (d(0) = 25-80 nm) for the various macromolecular species, showed that the multilayer film growth was inhibited at different maximum numbers of LbL steps (n(max)). The value of n(max) was greatest for linear-PEs, while proteins had a lower value. The cylindrical pore geometry imposes a physical limit to LbL growth such that n(max) is strongly dependent on the overall internal structure of the LbL film. For all macromolecular species, deposition was inhibited in native AAO, having pores of d(0) = 25-30 nm. Both, OWS and scanning electron microscopy showed that LbL growth in larger AAO pores (d(0) > 25-30 nm) became inhibited when approaching a pore diameter of d(eff,n_max) = 25-35 nm, a similar size to that of native AAO pores, with d(0) = 25-30 nm. For a reasonable estimation of d(eff,n_max), the actual volume occupied by a macromolecular assembly must be taken into consideration. The results clearly show that electrostatic LbL allowed for compact macromolecular layers, whereas proteins formed loosely packed multilayers.

Optical properties of helical cylindrical molecular aggregates : the homogeneous limit

NARCIS (Netherlands)

Didraga, C.; Klugkist, J.A.; Knoester, J.

2002-01-01

Using a Frenkel exciton model, we study the optical absorption spectrum and linear and circular dichroism (CD) spectra of cylindrical molecular aggregates. We demonstrate that such aggregates can always be described as a stack of molecular rings with nearest-neighbor rings rotated relative to each

Optical Properties of Helical Cylindrical Molecular Aggregates : The Homogeneous Limit

NARCIS (Netherlands)

Didraga, Cătălin; Klugkist, Joost A.; Knoester, Jasper

2002-01-01

Using a Frenkel exciton model, we study the optical absorption spectrum and linear and circular dichroism (CD) spectra of cylindrical molecular aggregates. We demonstrate that such aggregates can always be described as a stack of molecular rings with nearest-neighbor rings rotated relative to each

Implementation of an algorithm for cylindrical object identification using range data

Science.gov (United States)

Bozeman, Sylvia T.; Martin, Benjamin J.

1989-01-01

One of the problems in 3-D object identification and localization is addressed. In robotic and navigation applications the vision system must be able to distinguish cylindrical or spherical objects as well as those of other geometric shapes. An algorithm was developed to identify cylindrical objects in an image when range data is used. The algorithm incorporates the Hough transform for line detection using edge points which emerge from a Sobel mask. Slices of the data are examined to locate arcs of circles using the normal equations of an over-determined linear system. Current efforts are devoted to testing the computer implementation of the algorithm. Refinements are expected to continue in order to accommodate cylinders in various positions. A technique is sought which is robust in the presence of noise and partial occlusions.

Insights into Integrated Lead Generation and Target Identification in Malaria and Tuberculosis Drug Discovery.

Science.gov (United States)

Okombo, John; Chibale, Kelly

2017-07-18

New, safe and effective drugs are urgently needed to treat and control malaria and tuberculosis, which affect millions of people annually. However, financial return on investment in the poor settings where these diseases are mostly prevalent is very minimal to support market-driven drug discovery and development. Moreover, the imminent loss of therapeutic lifespan of existing therapies due to evolution and spread of drug resistance further compounds the urgency to identify novel effective drugs. However, the advent of new public-private partnerships focused on tropical diseases and the recent release of large data sets by pharmaceutical companies on antimalarial and antituberculosis compounds derived from phenotypic whole cell high throughput screening have spurred renewed interest and opened new frontiers in malaria and tuberculosis drug discovery. This Account recaps the existing challenges facing antimalarial and antituberculosis drug discovery, including limitations associated with experimental animal models as well as biological complexities intrinsic to the causative pathogens. We enlist various highlights from a body of work within our research group aimed at identifying and characterizing new chemical leads, and navigating these challenges to contribute toward the global drug discovery and development pipeline in malaria and tuberculosis. We describe a catalogue of in-house efforts toward deriving safe and efficacious preclinical drug development candidates via cell-based medicinal chemistry optimization of phenotypic whole-cell medium and high throughput screening hits sourced from various small molecule chemical libraries. We also provide an appraisal of target-based screening, as invoked in our laboratory for mechanistic evaluation of the hits generated, with particular focus on the enzymes within the de novo pyrimidine biosynthetic and hemoglobin degradation pathways, the latter constituting a heme detoxification process and an associated cysteine

Minimization of stress concentration factor in cylindrical pressure vessels with ellipsoidal heads

International Nuclear Information System (INIS)

Magnucki, K.; Szyc, W.; Lewinski, J.

2002-01-01

The paper presents the problem of stress concentration in a cylindrical pressure vessel with ellipsoidal heads subject to internal pressure. At the line, where the ellipsoidal head is adjacent to the circular cylindrical shell, a shear force and bending moment occur, disturbing the membrane stress state in the vessel. The degree of stress concentration depends on the ratio of thicknesses of both the adjacent parts of the shells and on the relative convexity of the ellipsoidal head, with the range for radius-to-thickness ratio between 75 and 125. The stress concentration was analytically described and, afterwards, the effect of these values on the stress concentration ratio was numerically examined. Results of the analysis are shown on charts

Axisymmetrical impulsive responses of an infinite circular cylindrical shell filled with liquid

International Nuclear Information System (INIS)

Ujihashi, Sadayuki; Matsumoto, Hiroyuki; Nakahara, Ichiro; Shigeta, Masayuki.

1986-01-01

In this paper, dynamic interaction phenomena on solid and liquid interfaces are discussed. Axisymmetrical responses of an infinite circular cylindrical shell perfectly filled with liquid are analyzed, based on Fluegge's theory for a circular cylindrical shell and the potential theory for the ideal fluid under conditions of the impulsive external band pressure given on the outer surface of the shell. The deflection and the moment of the shell and the pressure in the fluid are evaluated by using the numerical inversion of the Laplace transformation method. The approximate solution for the shell with an equivalent mass on it is analyzed and is evaluated, based on the solution for the solid and liquid interaction. (author)

Cylindrical polymer brushes with dendritic side chains by iterative anionic reactions

KAUST Repository

Zhang, Hefeng; Qu, Chengke; He, Junpo

2015-01-01

We report in this paper an easy method for the synthesis of cylindrical polymer brushes with dendritic side chains through anionic reaction. The synthesis is accomplished by iteratively grafting a living block copolymer, polyisoprene-. b

Lifting forces acting on a cylindrical magnet above a superconducting plane

International Nuclear Information System (INIS)

Yang, Z.J.; Johansen, T.H.; Bratsberg, H.; Bhatnagar, A.; Skjeltorp, A.T.

1992-01-01

Based on the London theory, we have calculated and measured the lifting force acting on a cylindrical magnet placed above a superconductor. Comparison between the theoretical expectation and experimental data shows a good agreement. (orig.)

Characterization of growth sectors in synthetic quartz grown from cylindrical seeds parallel to [0001] direction

Directory of Open Access Journals (Sweden)

Pedro Luiz Guzzo

2004-06-01

Full Text Available In the present study, the morphology and the impurity distribution were investigated in growth sectors formed around the [0001] axis of synthetic quartz crystals. Plates containing cylindrical holes and cylindrical bars parallel to [0001] were prepared by ultrasonic machining and further used as seed-crystals. The hydrothermal growth of synthetic quartz was carried out in a commercial autoclave under NaOH solution during 50 days. The morphologies of crystals grown from cylindrical seeds were characterized by X-ray diffraction topography. For both types of crystals, +X- and X- growth sectors were distinctly observed. Infrared spectroscopy and ionizing radiation were adopted to reveal the distribution of point defects related to Si-Al substitution and OH-species. It was found a different distribution of Al-related centers in relation to the crystals grown from conventional Y-bar and Z-plate seeds.

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding-gate MOSFETs

International Nuclear Information System (INIS)

Li Cong; Zhuang Yi-Qi; Zhang Li; Jin Gang

2014-01-01

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding-gate (JLDMCSG) metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed. It is derived by solving the two-dimensional Poisson's equation in two continuous cylindrical regions with any simplifying assumption. Using this analytical model, the subthreshold characteristics of JLDMCSG MOSFETs are investigated in terms of channel electrostatic potential, horizontal electric field, and subthreshold current. Compared to junctionless single-material cylindrical surrounding-gate MOSFETs, JLDMCSG MOSFETs can effectively suppress short-channel effects and simultaneously improve carrier transport efficiency. It is found that the subthreshold current of JLDMCSG MOSFETs can be significantly reduced by adopting both a thin oxide and thin silicon channel. The accuracy of the analytical model is verified by its good agreement with the three-dimensional numerical simulator ISE TCAD

Magnetization curves for general cylindrical samples in a transverse ...

Indian Academy of Sciences (India)

complexity associated with the task of determining and studying the movement of the flux- front as the flux ... a volume current density causing the flux-front to move by an appropriate amount. Since the flux-front does ... Let us consider an infinite cylindrical sample with its axis along the z-axis and its cross- section bounded ...

Target conception for the Munich fission fragment accelerator

CERN Document Server

Maier, H J; Gross, M L; Grossmann, R; Kester, O; Thirolf, P

1999-01-01

For the new high-flux reactor FRM II, the fission fragment accelerator MAFF is under design. MAFF will supply intense mass-separated radioactive ion beams of very neutron-rich nuclei with energies around the Coulomb barrier. A central part of this accelerator is the ion source with the fission target, which is operated at a neutron flux of 1.5x10 sup 1 sup 4 cm sup - sup 2 s sup - sup 1. The target consists of typically 1 g of sup 2 sup 3 sup 5 U dispersed in a cylindrical graphite matrix, which is encapsulated in a Re container. To enable diffusion and extraction of the fission products, the target has to be maintained at a temperature of up to 2400 deg. C during operation. It has to stand this temperature for at least one reactor cycle of 1250 h. Comprehensive tests are required to study the long-term behaviour of the involved materials at these conditions prior to operation in the reactor. The present paper gives details of the target conception and the projected tests.

Particle scavenging in a cylindrical ultrasonic standing wave field using levitated drops

Science.gov (United States)

Merrell, Tyler; Saylor, J. R.

2015-11-01

A cylindrical ultrasonic standing wave field was generated in a tube containing a flow of particles and fog. Both the particles and fog drops were concentrated in the nodes of the standing wave field where they combined and then grew large enough to fall out of the system. In this way particles were scavenged from the system, cleaning the air. While this approach has been attempted using a standing wave field established between disc-shaped transducers, a cylindrical resonator has not been used for this purpose heretofore. The resonator was constructed by bolting three Langevin transducers to an aluminum tube. The benefit of the cylindrical geometry is that the acoustic energy is focused. Furthermore, the residence time of the particle in the field can be increased by increasing the length of the resonator. An additional benefit of this approach is that tubes located downstream of the resonator were acoustically excited, acting as passive resonators that enhanced the scavenging process. The performance of this system on scavenging particles is presented as a function of particle diameter and volumetric flow rate. It is noted that, when operated without particles, the setup can be used to remove drops and shows promise for liquid aerosol retention from systems where these losses can be financially disadvantageous and/or hazardous.

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

International Nuclear Information System (INIS)

Lee, Joo Hee

2006-02-01

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)

Study of laminated anisotropic cylindrical shells sensitive to transverse stresses

International Nuclear Information System (INIS)

Massard, Thierry

1979-01-01

A variational method for the determination of stresses and displacements in a multilayered cylindrical shell is presented. All included materials are linearly anisotropic (monoclinic) - i.e. directional fibres reinforced materials. This study uses a functional which is derived from the potential energy of the structure. The incoming stresses are σ RR , σ Rθ , σ RZ , and the displacements are u θ and u Z . This mixed group is the main variables of the formulation. It is shown that the stationarity conditions of the functional are the equilibrium equations and the associated boundary conditions. An approximate solution can be found using a finite element method which realizes a tridimensional discretization of the structure. The program issued is a specific mean for studying the transverse shear stresses in laminated cylindrical structures. From the results obtained it can be concluded that it meets all requirements for the purposes of this range of problems. (author) [fr

Stability analysis of cylindrical Vlasov equilibria

International Nuclear Information System (INIS)

Short, R.W.

1979-01-01

A general method of stability analysis is described which may be applied to a large class of such problems, namely those which are described dynamically by the Vlasov equation, and geometrically by cylindrical symmetry. The method is presented for the simple case of the Vlasov-Poisson (electrostatic) equations, and the results are applied to a calculation of the lower-hybrid-drift instability in a plasma with a rigid rotor distribution function. The method is extended to the full Vlasov-Maxwell (electromagnetic) equations. These results are applied to a calculation of the instability of the extraordinary electromagnetic mode in a relativistic E-layer interacting with a background plasma

Explosion-Induced Implosions of Cylindrical Shell Structures

Science.gov (United States)

Ikeda, C. M.; Duncan, J. H.

2010-11-01

An experimental study of the explosion-induced implosion of cylindrical shell structures in a high-pressure water environment was performed. The shell structures are filled with air at atmospheric pressure and are placed in a large water-filled pressure vessel. The vessel is then pressurized to various levels P∞=αPc, where Pc is the natural implosion pressure of the model and α is a factor that ranges from 0.1 to 0.9. An explosive is then set off at various standoff distances, d, from the model center line, where d varies from R to 10R and R is the maximum radius of the explosion bubble. High-speed photography (27,000 fps) was used to observe the explosion and resulting shell structure implosion. High-frequency underwater blast sensors recorded dynamic pressure waves at 6 positions. The cylindrical models were made from aluminum (diameter D = 39.1 mm, wall thickness t = 0.89 mm, length L = 240 mm) and brass (D = 16.7 mm, t = 0.36 mm, L=152 mm) tubes. The pressure records are interpreted in light of the high-speed movies. It is found that the implosion is induced by two mechanisms: the shockwave generated by the explosion and the jet formed during the explosion-bubble collapse. Whether an implosion is caused by the shockwave or the jet depends on the maximum bubble diameter and the standoff distance.

Response of Solid and Liquid Targets to High Power Proton Beams for Neutrino Factories

CERN Document Server

Sievers, P

2000-01-01

The response of solid and liquid targets to rapid heating by the incident proton beam is assessed in a classical way, among other things by solving the wave equation under linear conditions and in cylindrical symmetry. This study provides bench mark values and allows to identify critical issues and limiting factors which can help to guide further investigations with more sophisticated means.

Laser-driven nuclear-polarized hydrogen internal gas target

International Nuclear Information System (INIS)

Seely, J.; Crawford, C.; Clasie, B.; Xu, W.; Dutta, D.; Gao, H.

2006-01-01

We report the performance of a laser-driven polarized internal hydrogen gas target (LDT) in a configuration similar to that used in scattering experiments. This target used the technique of spin-exchange optical pumping to produce nuclear spin polarized hydrogen gas that was fed into a cylindrical storage (target) cell. We present in this paper the performance of the target, methods that were tried to improve the figure-of-merit (FOM) of the target, and a Monte Carlo simulation of spin-exchange optical pumping. The dimensions of the apparatus were optimized using the simulation and the experimental results were in good agreement with the results from the simulation. The best experimental result achieved was at a hydrogen flow rate of 1.1x10 18 atoms/s, where the sample beam exiting the storage cell had 58.2% degree of dissociation and 50.5% polarization. Based on this measurement, the atomic fraction in the storage cell was 49.6% and the density averaged nuclear polarization was 25.0%. This represents the highest FOM for hydrogen from an LDT and is higher than the best FOM reported by atomic beam sources that used storage cells

Stress-deformed state of cylindrical specimens during indirect tensile strength testing

Directory of Open Access Journals (Sweden)

Levan Japaridze

2015-10-01

Full Text Available In this study, the interaction between cylindrical specimen made of homogeneous, isotropic, and linearly elastic material and loading jaws of any curvature is considered in the Brazilian test. It is assumed that the specimen is diametrically compressed by elliptic normal contact stresses. The frictional contact stresses between the specimen and platens are neglected. The analytical solution starts from the contact problem of the loading jaws of any curvature and cylindrical specimen. The contact width, corresponding loading angle (2θ0, and elliptical stresses obtained through solution of the contact problems are used as boundary conditions for a cylindrical specimen. The problem of the theory of elasticity for a cylinder is solved using Muskhelishvili's method. In this method, the displacements and stresses are represented in terms of two analytical functions of a complex variable. In the main approaches, the nonlinear interaction between the loading bearing blocks and the specimen as well as the curvature of their surfaces and the elastic parameters of their materials are taken into account. Numerical examples are solved using MATLAB to demonstrate the influence of deformability, curvature of the specimen and platens on the distribution of the normal contact stresses as well as on the tensile and compressive stresses acting across the loaded diameter. Derived equations also allow calculating the modulus of elasticity, total deformation modulus and creep parameters of the specimen material based on the experimental data of radial contraction of the specimen.

Simulation of electron, positron and Bremsstrahlung spectrum generated due to electromagnetic cascade by 2.5 GeV electron hitting lead target using FLUKA code

International Nuclear Information System (INIS)

Sahani, P.K.; Dev, Vipin; Haridas, G.; Thakkar, K.K.; Singh, Gurnam; Sarkar, P.K.; Sharma, D.N.

2009-01-01

INDUS-2 is a high energy electron accelerator facility where electrons are accelerated in circular ring up to maximum energy 2.5 GeV, to generate synchrotron radiation. During normal operation of the machine a fraction of these electrons is lost, which interact with the accelerator structures and components like vacuum chamber and residual gases in the cavity and hence generates significant amount of Bremsstrahlung radiation. The Bremsstrahlung radiation is highly dependent on the incident electron energy, target material and its thickness. The Bremsstrahlung radiation dominates the radiation environment in such electron storage rings. Because of its broad spectrum extending up to incident electron energy and pulsed nature, it is very difficult to segregate the Bremsstrahlung component from the mixed field environment in accelerators. With the help of FLUKA Monte Carlo code, Bremsstrahlung spectrum generated from 2.5 GeV electron on bombardment of high Z lead target is simulated. To study the variation in Bremsstrahlung spectrum on target thickness, lead targets of 3, 6, 9, 12, 15, 18 mm thickness was used. The energy spectrum of emerging electron and positron is also simulated. The study suggests that as the target thickness increases, the emergent Bremsstrahlung photon fluence increases. With increase in the target thickness Bremsstrahlung photons in the spectrum dominate the low energy part and degrade in high energy part. The electron and positron spectra also extend up to incident electron energy. (author)

Scattering Light by а Cylindrical Capsule with Arbitrary End Caps in the Rayleigh-Gans-Debye Approximation

Directory of Open Access Journals (Sweden)

K. A. Shapovalov

2015-01-01

Full Text Available The paper concerns the light scattering problem of biological objects of complicated structure.It considers optically “soft” (having a refractive index close to that of a surrounding medium homogeneous cylindrical capsules, composed of three parts: central one that is cylindrical and two symmetrical rounding end caps. Such capsules can model more broad class of biological objects than the ordinary shapes of a spheroid or sphere. But, unfortunately, if a particle has other than a regular geometrical shape, then it is very difficult or impossible to solve the scattering problem analytically in its most general form that oblige us to use numerical and approximate analytical methods. The one of such approximate analytical method is the Rayleigh-Gans-Debye approximation (or the first Born approximation.So, the Rayleigh-Gans-Debye approximation is valid for different objects having size from nanometer to millimeter and depending on wave length and refractive index of an object under small phase shift of central ray.The formulas for light scattering amplitude of cylindrical capsule with arbitrary end caps in the Rayleigh-Gans-Debye approximation in scalar form are obtained. Then the light scattering phase function [or element of scattering matrix f11] for natural incident light (unpolarized or arbitrary polarized light is calculated.Numerical results for light scattering phase functions of cylindrical capsule with conical, spheroidal, paraboloidal ends in the Rayleigh-Gans-Debye approximation are compared. Also numerical results for light scattering phase function of cylindrical capsule with conical ends in the Rayleigh-Gans-Debye approximation and in the method of Purcell-Pennypacker (or Discrete Dipole method are compared. The good agreement within an application range of the RayleighGans-Debye approximation is obtained.Further continuation of the work, perhaps, is a consideration of multilayer cylindrical capsule in the Rayleigh

Particle Creation in Oscillating Cavities with Cubic and Cylindrical Geometry

Science.gov (United States)

Setare, M. R.; Dinani, H. T.

2008-04-01

In the present paper we study the creation of massless scalar particles from the quantum vacuum due to the dynamical Casimir effect by oscillating cavities with cubic and cylindrical geometry. To the first order of the amplitude we derive the expressions for the number of the created particles.

Non-axial-symmetric Alfven waves in cylindrical, radial inhomogeneous plasmas

International Nuclear Information System (INIS)

Raeuchle, E.

1978-08-01

The propagation of nonaxialsymmetric Alfven waves is investigated theoretically. Eigenfunctions and dispersion relations are calculated numerically for radial inhomogeneous cylindrical plasmas. In the MHD treatment resistivity, neutral particle loading and ion cyclotron effects are included. The investigations are of importance for plasma heating by Alfven waves. (orig.) [de

Cylindrical Three-Dimensional Porous Anodic Alumina Networks

Directory of Open Access Journals (Sweden)

Pedro M. Resende

2016-11-01

Full Text Available The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.

Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation.

Science.gov (United States)

Oh, Seungtaik; Jeong, Il Kwon

2015-11-16

We will introduce a new simple analytic formula of the Fourier coefficient of the 3D field distribution of a point light source to generate a cylindrical angular spectrum which captures the object wave in 360° in the 3D Fourier space. Conceptually, the cylindrical angular spectrum can be understood as a cylindrical version of the omnidirectional spectral approach of Sando et al. Our Fourier coefficient formula is based on an intuitive observation that a point light radiates uniformly in all directions. Our formula is defined over all frequency vectors lying on the entire sphere in the 3D Fourier space and is more natural and computationally more efficient for all around recording of the object wave than that of the previous omnidirectional spectral method. A generalized frequency-based occlusion culling method for an arbitrary complex object is also proposed to enhance the 3D quality of a hologram. As a practical application of the cylindrical angular spectrum, an interactive hologram example is presented together with implementation details.

Rigid-Plastic Approximations for Predicting Plastic Deformation of Cylindrical Shells Subject to Dynamic Loading

Directory of Open Access Journals (Sweden)

Michelle S. Hoo Fatt

1996-01-01

Full Text Available A theoretical approach was developed for predicting the plastic deformation of a cylindrical shell subject to asymmetric dynamic loads. The plastic deformation of the leading generator of the shell is found by solving for the transverse deflections of a rigid-plastic beam/string-on-foundation. The axial bending moment and tensile force in the beam/string are equivalent to the longitudinal bending moments and membrane forces of the shell, while the plastic foundation force is equivalent to the shell circumferential bending moment and membrane resistances. Closed-form solutions for the transient and final deformation profile of an impulsive loaded shell when it is in a “string” state were derived using the eigenfunction expansion method. These results were compared to DYNA 3D predictions. The analytical predictions of the transient shell and final centerline deflections were within 25% of the DYNA 3D results.

Cylindrical Penning traps with dynamic orthogonalized anharmonicity compensation for precision experiments

International Nuclear Information System (INIS)

Fei Xiang; Snow, W.M.

1999-01-01

Harmonic potentials can be produced in cylindrical ion traps by means of dynamic orthogonalized anharmonicity compensation with use of two (or multiple) sets of compensation electrodes. One special example is for traps with multiple identical electrodes which are not only easy to construct and allow access to the center region of the trap for particle loading and releasing, laser beams, and microwaves, but also flexible in forming harmonic potential wells in many locations. The nested trap configuration and the side-by-side trap configuration are readily available in this special scheme. Analytical solutions for cylindrical traps with multiple sets of compensation potentials are presented. This work will be useful for studies involving Penning trap diagnostics, atomic and molecular interactions (including the production of antihydrogen atoms), accurate mass measurements of exotic particles, and precision measurements of the spin precession frequencies of trapped particles

Cylindrical Penning traps with dynamic orthogonalized anharmonicity compensation for precision experiments

CERN Document Server

Fei Xiang

1999-01-01

Harmonic potentials can be produced in cylindrical ion traps by means of dynamic orthogonalized anharmonicity compensation with use of two (or multiple) sets of compensation electrodes. One special example is for traps with multiple identical electrodes which are not only easy to construct and allow access to the center region of the trap for particle loading and releasing, laser beams, and microwaves, but also flexible in forming harmonic potential wells in many locations. The nested trap configuration and the side-by-side trap configuration are readily available in this special scheme. Analytical solutions for cylindrical traps with multiple sets of compensation potentials are presented. This work will be useful for studies involving Penning trap diagnostics, atomic and molecular interactions (including the production of antihydrogen atoms), accurate mass measurements of exotic particles, and precision measurements of the spin precession frequencies of trapped particles.

Profile of capillary bridges between two vertically stacked cylindrical fibers under gravitational effect

Science.gov (United States)

Sun, Xiaohang; Lee, Hoon Joo; Michielsen, Stephen; Wilusz, Eugene

2018-05-01

Although profiles of axisymmetric capillary bridges between two cylindrical fibers have been extensively studied, little research has been reported on capillary bridges under external forces such as the gravitational force. This is because external forces add significant complications to the Laplace-Young equation, making it difficult to predict drop profiles based on analytical approaches. In this paper, simulations of capillary bridges between two vertically stacked cylindrical fibers with gravitational effect taken into consideration are studied. The asymmetrical structure of capillary bridges that are hard to predict based on analytical approaches was studied via a numerical approach based on Surface Evolver (SE). The axial and the circumferential spreading of liquids on two identical fibers in the presence of gravitational effects are predicted to determine when the gravitational effects are significant or can be neglected. The effect of liquid volume, equilibrium contact angle, the distance between two fibers and fiber radii. The simulation results were verified by comparing them with experimental measurements. Based on SE simulations, curves representing the spreading of capillary bridges along the two cylindrical fibers were obtained. The gravitational effect was scaled based on the difference of the spreading on upper and lower fibers.

Numerical Simulation of the Layer-Bylayer Destruction of Cylindrical Shells Under Explosive Loading

Science.gov (United States)

Abrosimov, N. A.; Novoseltseva, N. A.

2015-09-01

A technique of numerical analysis of the influence of reinforcement structure on the nature of the dynamic response and the process of layer-by-layer destruction of layered fiberglass cylindrical shells under an axisymmetric internal explosive loading is elaborated. The kinematic model of deformation of the laminate package is based on a nonclassical theory of shells. The geometric dependences are based on simple quadratic relations of the nonlinear theory of elasticity. The relationship between the stress and strain tensors are established by using Hooke's law for orthotropic bodies with account of degradation of stiffness characteristics of the multilayer composite due to the local destruction of some its elementary layers. An energetically consistent system of dynamic equations for composite cylindrical shells is obtained by minimizing the functional of total energy of the shell as a three-dimensional body. The numerical method for solving the formulated initial boundary-value problem is based on an explicit variational-difference scheme. Results confirming the reliability of the method used to analyze the influence of reinforcement structure on the character of destruction and the bearing capacity of pulse-loaded cylindrical shells are presented.

Acoustic radiation from the submerged circular cylindrical shell treated with active constrained layer damping

Science.gov (United States)

Yuan, Li-Yun; Xiang, Yu; Lu, Jing; Jiang, Hong-Hua

2015-12-01

Based on the transfer matrix method of exploring the circular cylindrical shell treated with active constrained layer damping (i.e., ACLD), combined with the analytical solution of the Helmholtz equation for a point source, a multi-point multipole virtual source simulation method is for the first time proposed for solving the acoustic radiation problem of a submerged ACLD shell. This approach, wherein some virtual point sources are assumed to be evenly distributed on the axial line of the cylindrical shell, and the sound pressure could be written in the form of the sum of the wave functions series with the undetermined coefficients, is demonstrated to be accurate to achieve the radiation acoustic pressure of the pulsating and oscillating spheres respectively. Meanwhile, this approach is proved to be accurate to obtain the radiation acoustic pressure for a stiffened cylindrical shell. Then, the chosen number of the virtual distributed point sources and truncated number of the wave functions series are discussed to achieve the approximate radiation acoustic pressure of an ACLD cylindrical shell. Applying this method, different radiation acoustic pressures of a submerged ACLD cylindrical shell with different boundary conditions, different thickness values of viscoelastic and piezoelectric layer, different feedback gains for the piezoelectric layer and coverage of ACLD are discussed in detail. Results show that a thicker thickness and larger velocity gain for the piezoelectric layer and larger coverage of the ACLD layer can obtain a better damping effect for the whole structure in general. Whereas, laying a thicker viscoelastic layer is not always a better treatment to achieve a better acoustic characteristic. Project supported by the National Natural Science Foundation of China (Grant Nos. 11162001, 11502056, and 51105083), the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2012GXNSFAA053207), the Doctor Foundation of Guangxi

Nematic liquid crystal in a cylindrical sample: Theoretical analysis of the electrical response

Science.gov (United States)

Gomes, O. A.; Yednak, C. A. R.; da Silva, B. V. H. V.; Teixeira-Souza, R. T.

2018-02-01

The electrical responses of a nematic liquid crystal sample confined between two cylindrical surfaces are investigated in the framework of elastic continuum theory. The responses are the result of the molecular reorientation induced by both the applied electric field and the cylindrical geometry of the sample. The nematic medium is considered as a parallel RC circuit since the capacitance and the resistance are under the same difference of potential. The electrical properties, including the total electric current, are determined from the molecular reorientation of the director. The elastic anisotropy has been shown to influence substantially the profile of the electrical current, capacitance, and resistance characterizing the equivalent circuit for the medium.

Mathematical simulation of stressed-deformed state in rod cylindrical fuel elemnts KONDOR program

International Nuclear Information System (INIS)

Khmelevskij, M.Ya.; Malakhova, E.I.; Dolmatov, P.S.

1987-01-01

A mathematical model for numerical computation of stressed-deformed stae in a rod cylindrical fuel element is developed. The model is based on preliminary discretization of the design scheme and linearization of radial parameters as radius functions. The formulation generality enables to calculate strength parameter kinetics in any circular cylindrical fuel element (e.g. annular fuel element; solid or tubular core; ceramic, metallic or dispersion fuel) for arbitrary transient operating conditions and taking into account all possible loading factors. The method is realized in the KONDOR programm (FORTRAN, ES-1061 computer). An example illustrating computation of stress kinetics in a fast reactor fuel element during transient operation is given

Spatial mode structures of electrostatic drift waves in a collisional cylindrical helicon plasma

DEFF Research Database (Denmark)

Schröder, C.; Grulke, O.; Klinger, T.

2004-01-01

In a cylindrical helicon plasma, mode structures of coherent drift waves are studied in the poloidal plane, the plane perpendicular to the ambient magnetic field. The mode structures rotate with a constant angular velocity in the direction of the electron diamagnetic drift and show significant...... radial bending. The experimental observations are compared with numerical solutions of a linear nonlocal cylindrical model for drift waves [ Ellis , Plasma Phys. 22, 113 (1980) ]. In the numerical model, a transition to bended mode structures is found if the plasma collisionality is increased....... This finding proves that the experimentally observed bended mode structures are the result of high electron collisionality. (C) 2004 American Institute of Physics....

Data on mixing of viscous fluids by helical screw impellers in cylindrical vessels

Directory of Open Access Journals (Sweden)

Houari Ameur

2016-09-01

Full Text Available In this article, the data assembled regarding the mixing of Newtonian and shear thinning fluids by screw impellers in a cylindrical tank is disclosed. The data summarizing some information on the efficiency of such impellers are obtained via 3D calculations of velocities and viscous dissipation in the whole vessel volume. The data presented herein may be useful for those who want to outline the mixing characteristics in terms of fluid circulation and power consumption for this kind of impellers, therefore, avoiding a great effort for achieving a high number of experiments. Keyword: Mixing, Helical screw agitator, Power consumption, Fluid circulation, Cylindrical tanks

Prediction and experimental verification of performance of box type solar cooker - Part I. Cooking vessel with central cylindrical cavity

International Nuclear Information System (INIS)

Reddy, Avala Raji; Rao, A.V. Narasimha

2007-01-01

The performance of conventional box type solar cookers can be improved by better designs of cooking vessels with proper understanding of the heat flow to the material to be cooked. An attempt has been made in this article to arrive at a mathematical model to understand the heat flow process to the cooking vessel and thereby to the food material. The mathematical model considers a double glazed hot box type solar cooker loaded with two different types of vessels, kept either on the floor of the cooker or on lugs. The performance of the cooking vessel with a central cylindrical cavity is compared with that of a conventional cylindrical cooking vessel. It is found from the experiments and modeling that the cooking vessel with a central cylindrical cavity on lugs results in a higher temperature of the thermic fluid than that of a conventional vessel on the floor or on lugs. The average improvement of performance of the vessel with a central cylindrical cavity kept on lugs is found to be 5.9% and 2.4% more than that of a conventional cylindrical vessel on the floor and on lugs, respectively

Determination dimension and technical specification of the cylindrical pneumatics for the tote movement on multipurpose the gamma irradiator BATAN

International Nuclear Information System (INIS)

Muhammad Subhan; Ari Satmoko

2016-01-01

BATAN develops irradiator gamma category IV in cooperation with IZOTOP (Hungary). Transportation technology products that will be developed uses rail system to pool. Products that will be irradiated are put into tote then placed on the transportation rail, when tote has been in irradiated room tote enters into irradiated rack. The movement of the tote during on irradiated rack will be driven by the pneumatic system. Based on data from Isotop there are 14 cylindrical pneumatics that are in the irradiated room. Through the results analysis then used double acting cylinder type from the Festo pneumatics catalog. Through the results calculation that the force used on all types of cylinders for movement tote still much smaller than of force bent permitted. Beside that there are 4 group a pneumatic have common specifications they are group one cylindrical C1, C3, C12 and C14 they are group two cylindrical C2, C4, C11, and C13 they are group three cylindrical C7, C9, C15 and C17 they are group four cylindrical C10 and C17. (author)

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, 00). 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.

The control of quasiuniform heating of a cylindrical specimen in an inductor

Science.gov (United States)

Kuyanov, A. Yu.; Glasko, V. B.; Tikhonov, A. N.

1989-04-01

We have used a computer mathematically to experiment with and to formulate solutions for the problem of optimum control by means of quasiuniform heating of Foucault currents in cylindrical steel specimens.

Zero-point energy of N perfectly conducting concentric cylindrical shells

International Nuclear Information System (INIS)

Tatur, K.; Woods, L.M.

2008-01-01

The zero-point (Casimir) energy of N perfectly conducting, infinitely long, concentric cylindrical shells is calculated utilizing the mode summation technique. The obtained convergent expression is studied as a function of size, curvature and number of shells. Limiting cases, such as infinitely close shells or infinite radius shells are also investigated

Enhancement of critical currents in superconducting cylindrical samples by circular magnetization

Energy Technology Data Exchange (ETDEWEB)

Sikora, A; Makiej, B

1986-07-16

Evidence is presented for an enhancement of the critical current by a circular magnetization in cylindrical samples of superconductors such as Sn, In, and In-Pb alloy containing 20 wt% ferromagnetic carbon steel particles. The mechanism of this phenomenon is explained.

Cylindrical and spherical solitary waves in an electron-acoustic plasma with vortex electron distribution

Science.gov (United States)

Demiray, Hilmi; El-Zahar, Essam R.

2018-04-01

We consider the nonlinear propagation of electron-acoustic waves in a plasma composed of a cold electron fluid, hot electrons obeying a trapped/vortex-like distribution, and stationary ions. The basic nonlinear equations of the above described plasma are re-examined in the cylindrical (spherical) coordinates by employing the reductive perturbation technique. The modified cylindrical (spherical) KdV equation with fractional power nonlinearity is obtained as the evolution equation. Due to the nature of nonlinearity, this evolution equation cannot be reduced to the conventional KdV equation. A new family of closed form analytical approximate solution to the evolution equation and a comparison with numerical solution are presented and the results are depicted in some 2D and 3D figures. The results reveal that both solutions are in good agreement and the method can be used to obtain a new progressive wave solution for such evolution equations. Moreover, the resulting closed form analytical solution allows us to carry out a parametric study to investigate the effect of the physical parameters on the solution behavior of the modified cylindrical (spherical) KdV equation.

Neutron spectrum at 900 from 800 MeV (p,n) reactions on a Ta target

International Nuclear Information System (INIS)

Howe, S.D.; Lisowski, P.W.; King, N.S.P.; Russell, G.J.; Donnert, H.J.

1979-01-01

The neutron time-of-flight spectrum produced by a thick tantalum target bombarded by 800-MeV protons was measured at an angle of 90 0 . The data were taken at the Weapons Neutron Research facility by use of a cylindrical Ta target with a radius of 1.27 cm and a length of 15 cm. An NE-213 liquid scintillator was used to detect the neutrons over an energy range of 0.5 to 350 MeV. The neutron yield is presented and compared to a intranuclear-cascade/evaporation model prediction. 3 figures

Vertex detector working as an active target in multihadron production on nuclei

Energy Technology Data Exchange (ETDEWEB)

Albini, E [Istituto Nazionale di Fisica Nucleare, Milan (Italy); Brescia Univ. (Italy). Ist. di Matematica); Artuso, M; Bacchiocchi, G; D' Angelo, P; Moroni, L; Ragusa, F; Rancoita, P G; Sala, S [Istituto Nazionale di Fisica Nucleare, Milan (Italy); Bellini, G

1980-12-01

In this paper a vertex detector working as active target is described. It consists of a telescope of nuclear targets surrounded by two coaxial cylindrical MWPCs, working in the proportional regime. The energy loss in the two 6 mm gaps of the chambers is measured with an accuracy better than 18%. The coordinates of the track along the sense wires are measured using the charge division method with an accuracy of 0.5-1.0%. The efficiency is about 99.5%. This device is used in an experiment concerned with multihadron production on nuclei, coupled with a forward spectrometer in order to detect and recognize grey, black and shower secondary particles.

Phase domain structures in cylindrical magnets under conditions of a first-order magnetic phase transition

International Nuclear Information System (INIS)

Dzhezherya, Yu.I.; Klymuk, O.S.

2011-01-01

The magnetic and resonance properties of cylindrical magnets at first-order phase transition from paramagnetic to ferromagnetic state were theoretically studied. It has been shown that in the external magnetic field directed perpendicularly to the rotation axis, formation of a specific domain structure of paramagnetic and ferromagnetic layers can be energetically favorable. The parameters of cylindrical phase domains as well as their dependences on temperature, magnetic field and material characteristics have been calculated. Peculiarities of the magnetic resonance spectra appearing as a result of the phase domain formation have been considered. Dependence of the resonance field of the system of ferromagnetic domains on magnetization and temperature has been obtained. - Highlights: → Parameters of the equilibrium system of cylindrical phase domains are calculated. → The range of fields for PM and FM phases coexistence is found. → FMR field of the disk domains is found to be lower than that of the PMR field.→ The resonance field increases with the decrease of temperature lower than T || .

Design of roundness measurement model with multi-systematic error for cylindrical components with large radius.

Science.gov (United States)

Sun, Chuanzhi; Wang, Lei; Tan, Jiubin; Zhao, Bo; Tang, Yangchao

2016-02-01

The paper designs a roundness measurement model with multi-systematic error, which takes eccentricity, probe offset, radius of tip head of probe, and tilt error into account for roundness measurement of cylindrical components. The effects of the systematic errors and radius of components are analysed in the roundness measurement. The proposed method is built on the instrument with a high precision rotating spindle. The effectiveness of the proposed method is verified by experiment with the standard cylindrical component, which is measured on a roundness measuring machine. Compared to the traditional limacon measurement model, the accuracy of roundness measurement can be increased by about 2.2 μm using the proposed roundness measurement model for the object with a large radius of around 37 mm. The proposed method can improve the accuracy of roundness measurement and can be used for error separation, calibration, and comparison, especially for cylindrical components with a large radius.

static analysis of circular cylindrical shell under hydrostatic and ring

African Journals Online (AJOL)

DEPT OF AGRICULTURAL ENGINEERING

(Golzan et al, 2008). Circular cylindrical shells are used in a large variety of civil engineering structures, e.g. off-shore platforms, chimneys, silos, pipelines, bridge arches or wind turbine towers (Winterstetter et al, 2002). This work is concerned with the analysis of circular cylindri- cal shell subjected to hydrostatic pressure in.

Direct numerical solution of Poisson's equation in cylindrical (r, z) coordinates

International Nuclear Information System (INIS)

Chao, E.H.; Paul, S.F.; Davidson, R.C.; Fine, K.S.

1997-01-01

A direct solver method is developed for solving Poisson's equation numerically for the electrostatic potential φ(r,z) in a cylindrical region (r wall , 0 wall , z) are specified, and ∂φ/∂z = 0 at the axial boundaries (z = 0, L)

Analysis of the bending radius of the cylindrical waveguide of polydimethylsiloxane for the purpose of lighting

Science.gov (United States)

Novak, M.; Jargus, J.; Fajkus, M.; Bednarek, L.; Vasinek, V.

2017-10-01

Polydimethylsiloxane (PDMS) can be used for its optical properties and its composition offers the possibility of use in the dangerous environments. Therefore authors of this article focused on more detailed working with this material. The authors describe the use of PDMS polymer for the light transmission over short distances (up to tens of centimeters). PDMS offers good prerequisites (mechanical properties) for the creating cylindrical lighting waveguide e.g. for the purpose of the automotive industry. The objective is to determine the maximum bending radius of the cylindrical waveguide of polydimethylsiloxane for different wavelengths of the visible spectrum and thus extend the knowledge for subsequent use in lighting. The created cylindrical waveguide consist of a core and a cladding. Cladding was formed by a PDMS having a lower refractive index in order to respect the condition of total reflection.

Dispersion analysis and measurement of circular cylindrical wedge-like acoustic waveguides.

Science.gov (United States)

Yu, Tai-Ho

2015-09-01

This study investigated the propagation of flexural waves along the outer edge of a circular cylindrical wedge, the phase velocities, and the corresponding mode displacements. Thus far, only approximate solutions have been derived because the corresponding boundary-value problems are complex. In this study, dispersion curves were determined using the bi-dimensional finite element method and derived through the separation of variables and the Hamilton principle. Modal displacement calculations clarified that the maximal deformations appeared at the outer edge of the wedge tip. Numerical examples indicated how distinct thin-film materials deposited on the outer surface of the circular cylindrical wedge influenced the dispersion curves. Additionally, dispersion curves were measured using a laser-induced guided wave, a knife-edge measurement scheme, and a two-dimensional fast Fourier transform method. Both the numerical and experimental results correlated closely, thus validating the numerical solution. Copyright © 2015 Elsevier B.V. All rights reserved.

The size-dependent vibration of embedded magneto-electro-elastic cylindrical nanoshells

International Nuclear Information System (INIS)

Ke, Liao-Liang; Wang, Yue-Sheng; Yang, Jie; Kitipornchai, Sritawat

2014-01-01

Based on the nonlocal Love’s shell theory, this paper develops an embedded magneto-electro-elastic (MEE) cylindrical nanoshell model. This model incorporates effects of the small scale parameter and thermo-electro-magnetic loadings. The surrounding elastic medium is described as the Winkler model characterized by the spring. By using this model and the Hamilton principle, the governing equations and boundary conditions are derived for free vibration of the embedded MEE cylindrical nanoshells. The Navier’s method is first utilized to obtain the analytical solution for the simply supported MEE nanoshell. Then, numerical solutions for MEE nanoshells under various boundary conditions are obtained by using the differential quadrature (DQ) method. A detailed parametric study is conducted to highlight the influences of the nonlocal parameter, temperature rise, external electric potential, external magnetic potential, spring constant, radius-to-thickness ratio and length-to-radius ratio on natural frequencies of MEE nanoshells. (paper)

Effects of Boundary Conditions on the Parametric Resonance of Cylindrical Shells under Axial Loading

Directory of Open Access Journals (Sweden)

T.Y. Ng

1998-01-01

Full Text Available In this paper, a formulation for the dynamic stability analysis of circular cylindrical shells under axial compression with various boundary conditions is presented. The present study uses Love’s first approximation theory for thin shells and the characteristic beam functions as approximate axial modal functions. Applying the Ritz procedure to the Lagrangian energy expression yields a system of Mathieu–Hill equations the stability of which is analyzed using Bolotin’s method. The present study examines the effects of different boundary conditions on the parametric response of homogeneous isotropic cylindrical shells for various transverse modes and length parameters.

A novel target-field method for finite-length magnetic resonance shim coils: I. Zonal shims

International Nuclear Information System (INIS)

Forbes, Lawrence K.; Crozier, Stuart

2001-01-01

This paper presents a new approach for the design of genuinely finite-length shim and gradient coils, intended for use in magnetic resonance imaging equipment. A cylindrical target region is located asymmetrically, at an arbitrary position within a coil of finite length. A desired target field is specified on the surface of that region, and a method is given that enables winding patterns on the surface of the coil to be designed, to produce the desired field at the inner target region. The method uses a minimization technique combined with regularization, to find the current density on the surface of the coil. The method is illustrated for linear, quadratic and cubic magnetic target fields located asymmetrically within a finite-length coil. (author)

Multimode laser emission from free-standing cylindrical microcavities

Energy Technology Data Exchange (ETDEWEB)

Peter, Jaison, E-mail: jaisonpeter@cusat.ac.in; Radhakrishnan, P.; Nampoori, V.P.N.; Kailasnath, M.

2014-05-01

We report a well resolved whispering gallery mode (WGM) laser emission from a free-standing microring cavity based on a dye doped hollow polymer optical fiber (DDHPOF), which is transversely pumped by a pulsed Nd:YAG laser. The microring laser is characterized by a well-defined, low threshold pump power at which the emission spectral intensity dramatically increases and collapses into several dominant microcavity laser modes with reduced mode spacing and high Q-value. Resonant modes are excited inside the gain medium which is strongly confined along the radial direction so that the spacing of lasing modes is controlled by the diameter of the cylindrical microcavity. A variation in the free spectral range of WGM spectra from 0.23 to 0.09 nm coupled with a red-shift is observed with an increase in the diameter of DDHPOFs. - Highlights: • Different diameter free-standing cylindrical microcavity lasers have been fabricated and their performances have been evaluated. • The microring laser is characterized by a well-defined, low threshold pump power, with reduced mode spacing and high Q-value. • When the diameter of DDHPOF increases, the number of lasing peaks increases along with the decrease of the FSR as observed from our studies. • It is also found that whispering gallery lasing envelope is shifted from 559 to 571 nm (Stokes shift) with the diameter.

Positive synergistic effect of the reuse and the treatment of hazardous waste on pyrometallurgical process of lead recovery from waste lead-acid batteries

Directory of Open Access Journals (Sweden)

Marija Štulović

2014-09-01

Full Text Available Modification and optimization of the pyrometallurgical process of lead recovering from the waste lead-acid batteries have been studied in this paper. The aim of this research is to develop a cleaner production in the field of the secondary lead metallurgy. Lead smelting process with the addition of flux (sodium(I-carbonate and reducing agents (coke, iron has been followed. The modified smelting process with the addition of hazardous waste (activated carbon as alternative reducing agents has shown positive results on the quality of the secondary lead, the generated slag and the process gases. Filtration efficiency of the gases, the return of baghouse dust to the process and use of oxygen burners have positive effect on the environment protection and energy efficiency. Optimization of the recycling process has been based on the properties of the slag. Stabilization of slag is proposed in the furnace with addition of waste dust from the recycling of cathode ray tube (CRT monitors. Phosphorus compounds from dust reduce leachability of toxic elements from the generated slag. Reduction the slag amount and its hazardous character through the elimination of migratory heavy metals and valorization of useful components have been proposed in the patented innovative device - cylindrical rotating washer/separator.

Computer-Controlled Cylindrical Polishing Process for Large X-Ray Mirror Mandrels

Science.gov (United States)

Khan, Gufran S.; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian

2010-01-01

We are developing high-energy grazing incidence shell optics for hard-x-ray telescopes. The resolution of a mirror shells depends on the quality of cylindrical mandrel from which they are being replicated. Mid-spatial-frequency axial figure error is a dominant contributor in the error budget of the mandrel. This paper presents our efforts to develop a deterministic cylindrical polishing process in order to keep the mid-spatial-frequency axial figure errors to a minimum. Simulation software is developed to model the residual surface figure errors of a mandrel due to the polishing process parameters and the tools used, as well as to compute the optical performance of the optics. The study carried out using the developed software was focused on establishing a relationship between the polishing process parameters and the mid-spatial-frequency error generation. The process parameters modeled are the speeds of the lap and the mandrel, the tool s influence function, the contour path (dwell) of the tools, their shape and the distribution of the tools on the polishing lap. Using the inputs from the mathematical model, a mandrel having conical approximated Wolter-1 geometry, has been polished on a newly developed computer-controlled cylindrical polishing machine. The preliminary results of a series of polishing experiments demonstrate a qualitative agreement with the developed model. We report our first experimental results and discuss plans for further improvements in the polishing process. The ability to simulate the polishing process is critical to optimize the polishing process, improve the mandrel quality and significantly reduce the cost of mandrel production

Influence of magnetic field on the electrical breakdown characteristics in cylindrical diode

International Nuclear Information System (INIS)

Li Shouzhe; Uhm, Han S.

2004-01-01

The influence of magnetic field on the electrical breakdown properties is investigated by applying a magnetic field along the longitudinal direction in a cylindrical diode for two electrical polarities. Breakdown characteristics in a crossed magnetic field are analyzed with the equivalentreduced-electric-field concept and Townsend criterion. The discharge experiment at reduced pressure is carried out in the moderate magnetic field. Experimental investigation is concentrated on the magnetic dependent behavior of the electrical breakdown in the lower pressure side of Paschen's minimum. It is found that the electrical breakdown characteristics with respect to the magnetic field depend on electrical polarity of the cylindrical diode, which is interpreted by taking the gyromotion of the individual electrons in the diode into accounts under the moderate magnetic field in the lower pressure side of Paschen's minimum

Preparation of 235U target by electrodeposition

International Nuclear Information System (INIS)

Chen Qiping; Zhong Wenbin; Li Yougen

2004-12-01

A target for the production of fission 99 Mo in a nuclear reactor is composed of an enclosed, cylindrical vessel. Preferable vessel is comprised of stainless steel, having a thin, continuous, uniform layer of 235 U integrally bonded to its inner walls. Two processes are introduced for electrodepositing uranium on to the inner walls of the vessel. One processes is electrodepositing UO 2 from UO 2 (NO 3 ) 2 -(NH 4 ) 2 CO 4 ·H 2 O solution; the other is electrodepositing pure uranium metal from molten salt. Its plating efficiency and plating quantity from a molten bath is higher than UO 2 from the aqueous system. (authors)

Biomechanical evaluation of immediate stability with rectangular versus cylindrical interbody cages in stabilization of the lumbar spine

Directory of Open Access Journals (Sweden)

Webb John K

2002-10-01

Full Text Available Abstract Background Recent cadaver studies show stability against axial rotation with a cylindrical cage is marginally superior to a rectangular cage. The purpose of this biomechanical study in cadaver spine was to evaluate the stability of a new rectangular titanium cage design, which has teeth similar to the threads of cylindrical cages to engage the endplates. Methods Ten motion segments (five L2-3, five L4-5 were tested. From each cadaver spine, one motion segment was fixed with a pair of cylindrical cages (BAK, Sulzer Medica and the other with paired rectangular cages (Rotafix, Corin Spinal. Each specimen was tested in an unconstrained state, after cage introduction and after additional posterior translaminar screw fixation. The range of motion (ROM in flexion-extension, lateral bending, and rotation was tested in a materials testing machine, with +/- 5 Nm cyclical load over 10 sec per cycle; data from the third cycle was captured for analysis. Results ROM in all directions was significantly reduced (p Conclusions There was no significant difference in immediate stability in any direction between the threaded cylindrical cage and the new design of the rectangular cage with endplate teeth.

Modulation transfer function assessment in parallel beam and fan beam collimators with square and cylindrical holes.

Science.gov (United States)

Khorshidi, Abdollah; Ashoor, Mansour

2014-05-01

This study investigates modulation transfer function (MTF) in parallel beam (PB) and fan beam (FB) collimators using the Monte Carlo method with full width at half maximum (FWHM), square and circular-shaped holes, and scatter and penetration (S + P) components. A regulation similar to the lead-to-air ratio was used for both collimators to estimate output data. The hole pattern was designed to compare FB by PB parameters. The radioactive source in air and in a water phantom placed in front of the collimators was simulated using MCNP5 code. The test results indicated that the square holes in PB (PBs) had better FWHM than did the cylindrical (PBc) holes. In contrast, the cylindrical holes in the FB (FBc) had better FWHM than the square holes. In general, the resolution of FBc was better than that of the PBc in air and scatter mediums. The S + P decreased for all collimators as the distance from the source to the collimator surface (z) increased. The FBc had a lower S + P than FBs, but PBc had a higher S + P than PBs. Of the FB and PB collimators with the identical hole shapes, PBs had a smaller S + P than FBs, and FBc had a smaller S + P than PBc. The MTF value for the FB was greater than for the PB and had increased spatial frequency; the FBc had higher MTF than the FBs and PB collimators. Estimating the FB using PB parameters and diverse hole shapes may be useful in collimator design to improve the resolution and efficiency of SPECT images.

A cylindrical drift chamber with azimuthal and axial position readout

International Nuclear Information System (INIS)

Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M.

1997-01-01

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.)

Cullet Manufacture Using the Cylindrical Induction Melter

International Nuclear Information System (INIS)

Miller, D. H.

2000-01-01

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

Response of an annular electrostatic probe for a right cylindrical spacer

DEFF Research Database (Denmark)

Johansson, Torben; MacAllister, I. W.

2002-01-01

The response of an annular electrostatic probe mounted in an electrode is examined with reference to a right cylindrical spacer. The study involves using the probe λ function to derive characteristic parameters. These parameters enable the response of the probe to different charge distributions...