Round Beam Research Articles

An Analytical Model for Dosimetry of Nonstandard Photon Beams with Small, Round Cross Sections

An analytical model of the dose kernel of a narrow photon beam (pencil beam) with a bremsstrahlung spectrum with maximal energy at 6 MeV was created, allowing determination of the primary and scattered components of the absorbed dose to be determined in a water phantom with error levels acceptable in practice. A simple method for the dosimetry of photon beams with small round cross sections with 6-MV bremsstrahlung spectra using this model is proposed, combining absolute measurement of the dose absorbed in the water at a reference point in the machine-specific reference geometry and calculation of the deep dose distribution using simple analytical equations for round beams with cross sections of any radius.

Springback coefficient of round steel beam under elastoplastic torsion

Springback coefficient of round steel beam under elastoplastic torsion

Round Beam Studies at NSLS-II

Round Beam Studies at NSLS-II

Noninterleaved round beam lattice for light sources

A conceptual design and performance of a round beam lattice for synchrotron light sources based on the phase space exchange principle and the noninterleaved sextupole distribution is presented. Optics design is performed for an approximately 30 pm emittance 6 GeV machine of 2300 m circumference which combines cells with and without straight sections for the insertion devices.7 MoreReceived 16 March 2018DOI:https://doi.org/10.1103/PhysRevAccelBeams.21.051601Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeam opticsLattices in beam opticsAccelerators & Beams

ELASTOPLASTIC BEND OF ROUND STEEL BEAM. REPORT 1. SPRINGBACK COEFFICIENT

The round steel beam is widely used in metallurgy, mechanical engineering, construction and is one of the major players in the engine industry. Having the excellent anti-corrosion properties, combined with a remarkable strength, the round steel beam is often indispensable in the production of the various mechanical machines and devices. The cylindrical springs for the railway and motor transport are made from the round beam with the help of the special bending machines. Billets from the round beam are also used in the metallurgy at the manufacture of seamless pipes for the oil and gas industry. The rollers of the sheet-straightening machines and rolling mills in metallurgy have the form of stepped round beam. The steel construction armature is made from the round beam and is close to it by geometric dimensions. The main foreign producers of continuous-casting-billets machines for production of round-cross-section blanks are SMS-Demag (Germany), Danieli (Italy), SMS Concast (Switzerland) and Siemens VAI (Austria). The modern production of round steel beam has place on many Russian metallurgical plants, for example, on JSC “Chusovskoy metallurgical plant”, PJSC “Chelyabinsk metallurgical plant”, JSC “Volzhsky pipe plant”, OJSC “Nizhneserginsky metizno-metallurgical plant”, JSC “Chepetsky mechanical plant”, PJSC “Seversky pipe plant” and PJSC “Taganrog metallurgical plant”. In manufacture of articles from round beam and under their exploitation, they often have an elastic or elastoplastic deformation of bending or have a complex deformation of torsion with bending. The analytical method for determining residual curvature of round steel beam under elastoplastic bend is proposed in this paper. The calculations allow us to determine residual curvature of round beam after bending and the bending moments of beam’s cross section at bending depending on the beam’ radius, elastic modulus, yield stress and hardening modulus of beam’s metal. The research results can be widely used at engineering and metallurgical plants.

Elastoplastic Flexure of Round Steel Beams. 1. Springback Coefficient

Round steel beams are widely used in metallurgy, manufacturing, and construction. It is often irreplaceable in the production of machines and mechanical equipment on account of its excellent corrosion resistance and remarkable strength. Cylindrical springs for road and railroad vehicles are manufactured from round beams by means of special bending machines. Round beams also serve as blanks in the production of seamless pipe for the oil and gas industry. Stepped round beams are used as rollers in rolling and straightening mills. Steel rebar is manufactured from round beams of similar size. Outside Russia, the main producers of continuous-casting machines for the production of round billet are SMS Demag (Germany), Danieli (Italy), SMS Concast (Switzerland), and Siemens VAI (Austria). Russian producers include AO Chusovskii Metallurgicheskii Zavod, PAO Chelyabinskii Metallurgicheskii Kombinat, AO Volzhskii Trunbnyi Zavod, OAO Nizhneserginskii Metizno-Metallurgicheskii Zavod, AO Chepetskii Mekhanicheskii Zavod, PAO Severskii Trubnyi Zavod, and PAO Taganrogskii Metallurgicheskii Zavod. In the manufacture of parts from round beams and their use, they often experience elastic or elastoplastic flexure or complex torsion and flexure. In the present work, we propose an analytical method of calculating the residual curvature of round steel beams in elastoplastic flexure. In the calculations, the residual curvature of the round beam after flexure and the bending moments of the beam cross section in flexure are determined as a function of the beam radius, the Young’s modulus, the yield point, and the hardening modulus of the steel. The results may be widely used at manufacturing and metallurgical plants.

Calorimetry of the CMD-3 detector

The CMD-3 detector has been collecting data since 2010 at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. VEPP-2000 uses the novel round beam technique and provides high luminosity in a wide c.m.energy range from 0.32 to 2 GeV. The physics goal of the CMD-3 experiment is a study of the e+e− annihilation into hadrons. CMD-3 is a general-purpose detector, which provides high efficiency for both charged and neutral particles. The electromagnetic calorimeter consists of the barrel calorimeter based on liquid xenon and CsI crystals, and the endcap calorimeter based on BGO crystals. The main parameters of the calorimeters are presented.

Stimulating Vibration in Magnetoelastic Beams by the Circumferential Fields of Conducted Currents

A means to cause continuous vibratory deflection of a flexurally stressed beam of ferromagnetic, non-zero magnetostriction material, by a longitudinally conducted time varying current is described. The deflection of a horizontal cantilever beam, caused by a weight attached at its free end, is due to a difference in strains between those regions under tensile stress and those under compressive stress, in which these strains have both mechanical and magnetoelastic components. The circumferential uniformity of the field from the current acts to reduce the magnetoelastic strain inequality, hence also a small portion of the beam's deflection. Alternating between current on and current off thus acts to raise and lower the weight. Cycling the applied current at a frequency that matches the prime mode frequency will produce vibratory deflection. Round wire beams, 20-85 mm long, ~1 mm diameter, of three different materials, with attached weights ranging from 60 to 600 mN were made to vibrate at their specific natural frequency (8-80 Hz) with peak strokes up to >10 mm by currents alternating between 0 and up to 9 A.

AVALIAÇÃO NUMÉRICA DO MÓDULO DE ELASTICIDADE EM VIGAS ROLIÇAS DE MADEIRA DA ESPÉCIE <i>Pinus elliottii</i>

Este trabalho objetivou apresentar uma metodologia numérica de cálculo, fundamentada no Método dos Elementos Finitos e no Método dos Mínimos Quadrados, para obtenção do módulo de elasticidade longitudinal em vigas roliças de madeira de dimensões estruturais, considerando a influência das irregularidades na geometria das peças por aproximações lineares ao longo dos elementos finitos. Além do modelo numérico desenvolvido (1D), foram utilizados em conjunto outros dois, um analítico (simplificado 1D), que considera um único valor de diâmetro (geometria cilíndrica), medido no ponto médio da peça, e outro numérico (3D), que também permite delinear, de forma mais precisa, a geometria dos elementos estruturais roliços, possibilitando verificar as diferenças entre ambos. Para tanto, as vigas foram ensaiadas segundo o modelo de flexão estática a três pontos, sendo testadas 24 peças roliças de madeira da espécie Pinus elliottii, com comprimento médio de 630 cm, diâmetro médio das peças de 21 cm, madeira verde (saturada), conicidade média de 6% e fator de forma médio da seção de 0,82. Os resultados do intervalo de confiança entre os módulos de elasticidade do modelo numérico 1D (Eo) e analítico (Edeq) revelaram a equivalência estatísticas entre as metodologias, justificadas pela pequena conicidade das peças avaliadas, podendo ser diferentes para outras conicidades. O emprego dos módulos de elasticidade obtidos do modelo numérico 1D nas simulações dos elementos roliços em três dimensões conduziram a valores de deslocamentos equivalentes aos obtidos nas experimentações, comprovando a eficiência do modelo numérico 1D, mostrando ser este último mais interessante por exigir menor esforço computacional.

Elasticity moduli in round wooden beams of Pinus caribaea

ABSTRACT This research aimed at estimating both longitudinal (E) and shear (G) elasticity moduli of round structural-sized beams made of Pinus caribaea timber, verifying thus the validity of the G = E/ 20 relationship established by the Brazilian standard ABNT NBR 7190: 1997 (Designing of Wooden Structures). We tested twenty pieces of green wood with average length, diameter and conicity of 750 cm, 30 cm and 4%, respectively. Two static bending tests were applied at three points of each piece, being nondestructive and using different distances between supports. In the first trial, the length and diameter relationship (L/ d) was set as being equal to 24; yet in the second test, it was set at 12. The elasticity moduli were estimated by a successive use of the Timoshenko beam theory equation, which takes into account the shearing stress effect on displacement calculations. The results of both longitudinal and shear moduli were related through the least square assessment method; thus, we could find a relationship of G = E/ 43. As a result, we observed that the tested wooden pieces are at odds with the Brazilian standards.

Mechanical design, multiple criteria decision making and Pareto optimality gap

Purpose We present an approach to multiple criteria mechanical design problems, for cases where problem complexity precludes derivation of the whole Pareto front. For such problems we propose to limit search, and hence also derivation, of the Pareto front exclusively to regions of the direct designer’s interest, thus saving on computing efforts and gaining on tractable problem sizes. Design/methodology/approach To achieve the purpose, we frame the decision making process (design) into a combination of three specific concepts, namely decision maker's preference capture, local Pareto front search and approximate multiobjective optimization with assessments of the Pareto optimality gap. We illustrate the approach with two small design problems, namely Pareto optimal round tube beam and Pareto optimal pneumatic high speed machine drive selection. We solve these problems in a setting which can be regarded as representative for problem solving in real environment. Findings On the decision making side, the proposed approach has turned out to be a versatile tool for selecting designs from the Pareto suboptimal ones, where each such a Pareto suboptimal design has an explicit assessment of the Pareto optimality gap. On the technical (optimization) side, it has been demonstrated that the approach seamlessly works with evolutionary computations, structured to the specific needs of the approach. Research limitations/implications It has been shown that the navigation over the Pareto front can be achieved with limited effort, both on the cognitive and the computing side. Moreover, navigation over the Pareto front can be focused from the very beginning of the design selection process on the regions of the Pareto front which are of the direct designer’s interest. This eliminates the need to derive (or only approximate) the whole Pareto front, a tangible asset as the derivation of that set is the main factor precluding scalability of design selection problems to higher dimensions (to higher problem sizes). Practical implications Because of the general formulation of the Pareto optimal design selection problem considered in the paper, the absence of any assumptions on its form and easiness of implementation of the underlying procedure of the proposed approach, the paper offers a clear option to approaches based on classical optimization computations. Originality/value The approach offers derivation of Pareto suboptimal designs with assessments of the Pareto optimality gap, whereas currently available multiobjective evolutionary optimization algorithms which derive Pareto suboptimal designs as well, offer no such assessments. Thus, the approach provides a firm ground to valuate designs resulting from approximate multiobjective optimization computations.

Free-energy formula for emittance-growth estimation in intense mismatched beams

We construct a theoretical model that allows a quick estimate of emittance growth in an intense charged-particle beam initially mismatched to an external linear focusing potential. The present theory is a natural generalization of Reiser's free-energy model for coasting round beams in a uniform focusing channel. The free energy generated by a spatial mismatch, i.e. a discrepancy between the ideal beam size and an actual beam size, is calculated for an ellipsoidal bunch with an arbitrary aspect ratio. Following Reiser's prescription, we assume that the excess free energy is converted into root-mean-squared emittance growth. Multi-particle simulations are performed for comparison with theoretical predictions, which indicates that an initially mismatched bunch eventually settles into a sort of thermally anisotropic state when the mismatch is large. It is shown that the free-energy formula can explain simulation results over a wide range of parameters if the degree of the temperature anisotropy in the final state is properly incorporated into the theory.

Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams

Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams

A novel triple repeat mutant tau transgenic model that mimics aspects of pick's disease and fronto-temporal tauopathies.

Tauopathies are a group of disorders leading to cognitive and behavioral impairment in the aging population. While four-repeat (4R) Tau is more abundant in corticobasal degeneration, progressive supranuclear palsy, and Alzheimer’s disease, three-repeat (3R) Tau is the most abundant splice, in Pick's disease. A number of transgenic models expressing wild-type and mutant forms of the 4R Tau have been developed. However, few models of three-repeat Tau are available. A transgenic mouse model expressing three-repeat Tau was developed bearing the mutations associated with familial forms of Pick's disease (L266V and G272V mutations). Two lines expressing high (Line 13) and low (Line 2) levels of the three-repeat mutant Tau were analyzed. By Western blot, using antibodies specific to three-repeat Tau, Line 13 expressed 5-times more Tau than Line 2. The Tau expressed by these mice was most abundant in the frontal-temporal cortex and limbic system and was phosphorylated at residues detected by the PHF-1, AT8, CP9 and CP13 antibodies. The higher-expressing mice displayed hyperactivity, memory deficits in the water maze and alterations in the round beam. The behavioral deficits started at 6-8 months of age and were associated with a progressive increase in the accumulation of 3R Tau. By immunocytochemistry, mice from Line 13 displayed extensive accumulation of 3R Tau in neuronal cells bodies in the pyramidal neurons of the neocortex, CA1-3 regions, and dentate gyrus of the hippocampus. Aggregates in the granular cells had a globus appearance and mimic Pick’s-like inclusions. There were abundant dystrophic neurites, astrogliosis and synapto-dendritic damage in the neocortex and hippocampus of the higher expresser line. The hippocampal lesions were moderately argyrophilic and Thioflavin-S negative. By electron microscopy, discrete straight filament aggregates were detected in some neurons in the hippocampus. This model holds promise for better understanding the natural history and progression of 3R tauopathies and their relationship with mitochondrial alterations and might be suitable for therapeutical testing.

Analysis of the longitudinal space charge impedance of a round uniform beam inside parallel plates and rectangular chambers

This paper analyzes the longitudinal space charge (LSC) impedances of a round uniform beam inside a rectangular and parallel plate chambers using the image charge method. This analysis is valid for arbitrary wavelengths and the calculation converges fast. The research shows that only a few of the image beams are needed to obtain a relative error less than 0.1%. The beam offset effect is also discussed in the analysis.

An ultimate storage ring lattice with vertical emittance generated by damping wigglers

We discuss the approach of generating round beams for ultimate storage rings using vertical damping wigglers (with horizontal magnetic field). The vertical damping wigglers provide damping and excite vertical emittance. This eliminates the need to generate large linear coupling that is impractical with traditional off-axis injection. We use a PEP-X compatible lattice to demonstrate the approach. This lattice uses separate quadrupole and sextupole magnets with realistic gradient strengths. Intrabeam scattering effects are calculated. The horizontal and vertical emittances are 22.3pm and 10.3pm, respectively, for a 200mA, 4.5GeV beam, with a vertical damping wiggler of a total length of 90m, a peak field of 1.5T and a wiggler period of 100mm.

Approximate longitudinal space charge impedances of a round beam between parallel plates and inside a rectangular chamber

This paper presents the approximate analytical solutions to the longitudinal space charge (LSC) impedances of a round beam with uniform transverse distribution and sinusoidal line density modulations under two boundary conditions: (a) between parallel plates (b) inside a rectangular chamber, respectively. When the ratio of beam diameter to chamber height is small, the image charge fields of the round beam can be approximated by those of a line charge, the approximate analytical LSC impedances can be obtained by image method. The derived theoretical LSC impedances are valid at any perturbation wavelength and are consistent well with the numerical simulation results in a large range of ratios of beam diameters to chamber heights.

Generalized Representation of Electric Fields in Sheet Beam Klystron Gaps

Kosmahl and Branch's derivation for the electric field in a round beam gap is closely followed to derive the electric field for a sheet beam klystron gap. The wider of the two transverse dimensions of the gap is taken to be infinite in extent and the field is derived based on an approximation of the gap field at the drift tube edge. The electric field equations are generalized using a Fourier series representation of the gap field at the drift tube edge. The analytical results are compared with the numerical computations.

Design Sheet Beam Gun for THz Traveling-Wave Tube

The Sheet Electron Beam Vacuum Electron Device is an Attractive Choice for Generating High Power Millimeter/terahertz Wave Radiation. the Sheet Electron Beam Gun is a Key Component for the Sheet Beam Vacuum Electron Device. in this Paper, a Novel Sheet Electron Beam Gun was Proposed for a Terahertz Traveling-Wave Tube. the Theories of Sheet Beam Gun are Deduced Based on the Round Beam Gun Theories. the Track of 24.5kV, 1A, 0.4mm8mm Sheet Beam is Gained through 3D Particle-in-Cell Simulation and the Theories are Verified. the Investigation Results Show that, the Design Method of the Sheet Beam Gun is Easy and Reliable.

Research on applications of rectangular beam in micro laser propulsion

Micro laser propulsion is a new technology with brilliant future. In order to reduce the thruster mass and volume further, laser bar is introduced into the micro laser propulsion field. A new kind of 220×20μm rectangular beam of 808nm was obtained by oval lens compressing the light of diode at fast axes and slow axes. The effect of laser power, energy and coating thickness of double base propellant on propulsion performance was studied. Propulsion performance of double base propellant under static and dynamic mode shows some different characters. Compared to round beam, the new beam prefers to produce higher impulse. Ablation efficiency of DBP shows better performance in short laser duration. The combination of power density and energy density decides the laser propulsion performance. The new rectangular beam is appropriate for millisecond micro-laser propulsion.