The Experts below are selected from a list of 20376 Experts worldwide ranked by ideXlab platform
D.s. Venkateswarlu - One of the best experts on this subject based on the ideXlab platform.
-
Effective simulation of the Radial Thickness of helix for broad band, practical TWT's
IEEE Transactions on Plasma Science, 1999Co-Authors: M. V. Kartikeyan, Ashok K. Sinha, H. N. Bandopadhyay, D.s. VenkateswarluAbstract:A generalized analytical model has been developed to simulate the Radial Thickness of the helix employed in practical traveling wave tubes. With this proposed model, the exact physical dimensions of the helix Radial Thickness can be incorporated in the design equations. Relevant dispersion relations, characteristic and interaction impedances, and equivalent circuit parameters are derived by making use of both the field theory and equivalent analysis methods. Besides, in the field theory approach, a novel technique has been introduced to reduce the complexity in the derivation of the design formula. The results obtained using the present model are critically assessed, for four different practical slow-wave structures, over a wide range of experimental frequencies and found to be better than those obtained using earlier models.
-
An improved approach for the simulation of Radial Thickness of helix for practical TWTs
ICMMT'98. 1998 International Conference on Microwave and Millimeter Wave Technology. Proceedings (Cat. No.98EX106), 1998Co-Authors: M. V. Kartikeyan, Ashok K. Sinha, H. N. Bandopadhyay, D.s. VenkateswarluAbstract:A new approach incorporating the exact physical dimension of the helix has been proposed to simulate the Radial Thickness of the helix employed in a practical TWT. The dispersion results obtained using the present approach are applied to three different practical slow-wave structures in TWTs over a wide range of frequencies and found to be better than those obtained using earlier approaches.
Hiroshi Yamaoka - One of the best experts on this subject based on the ideXlab platform.
-
Conceptual design of the ATLAS thin superconducting solenoid magnet
IEEE Transactions on Applied Superconductivity, 1997Co-Authors: Yasuhiro Makida, Yoshikuni Doi, Tomiyoshi Haruyama, T. Kondo, Kenichi Tanaka, Akira Yamamoto, Hiroshi YamaokaAbstract:A thin superconducting solenoid has been designed to be installed into one of the major colliding particle detecting facilities, ATLAS, for LHC (Large Hadron Collider) project at CERN. The thin solenoidal coil wound with stiffened aluminum stabilized superconductor is indirectly cooled by forced two-phase helium through one serpentine tube on the outer support cylinder. The coil is installed into a common vacuum vessel with another co-axial cryogenic component, LAr-Cal, to save the wall material to trajectories for particles. Triangle-shape supporting elements on both ends of the coil are newly introduced to reduce a Radial Thickness of the cryostat.
Yuming Fang - One of the best experts on this subject based on the ideXlab platform.
-
Single-phase-lag thermoelastic damping models for rectangular cross-sectional micro- and nano-ring resonators
International Journal of Mechanical Sciences, 2019Co-Authors: Hongyue Zhou, Yuming FangAbstract:Abstract Employing the non-Fourier theory of single-phase-lag (SPL) model, the analytical thermoelastic damping (TED) models for rectangular cross-sectional micro- and nano-ring resonators with heat conduction along the Radial Thickness direction and the circumferential direction are derived in this paper. Specially, for only considering one-dimensional (1D) heat conduction along the Radial Thickness direction, the 1D-SPL TED model of the ring derived is consistent with that of the beam reported previously. The dependence of TED behaviors on the single-phase-lag time, geometry dimensions, the modal order, the material type, and the equilibrium temperature is explored. The TED spectra with single- or multiple-peak phenomenon under the effect of single-phase-lag time are discussed, which can be completely characterized by the present models in the series form. The results reveal that the dimensions of heat conduction and the effect of single-phase-lag time have significant influences on TED behaviors of micro- and nano-ring resonators.
-
Thermoelastic damping in thin microrings with two-dimensional heat conduction
Physica E-low-dimensional Systems & Nanostructures, 2015Co-Authors: Yuming FangAbstract:Abstract Accurate determination of thermoelastic damping (TED) is very challenging in the design of micro-resonators. Microrings are widely used in many micro-resonators. In the past, to model the TED effect on the microrings, some analytical models have been developed. However, in the previous works, the heat conduction within the microring is modeled by using the one-dimensional approach. The governing equation for heat conduction is solved only for the one-dimensional heat conduction along the Radial Thickness of the microring. This paper presents a simple analytical model for TED in microrings. The two-dimensional heat conduction over the thermoelastic temperature gradients along the Radial Thickness and the circumferential direction are considered in the present model. A two-dimensional heat conduction equation is developed. The solution of the equation is represented by the product of an assumed sine series along the Radial Thickness and an assumed trigonometric series along the circumferential direction. The analytical results obtained by the present 2-D model show a good agreement with the numerical (FEM) results. The limitations of the previous 1-D model are assessed.
M. V. Kartikeyan - One of the best experts on this subject based on the ideXlab platform.
-
Effective simulation of the Radial Thickness of helix for broad band, practical TWT's
IEEE Transactions on Plasma Science, 1999Co-Authors: M. V. Kartikeyan, Ashok K. Sinha, H. N. Bandopadhyay, D.s. VenkateswarluAbstract:A generalized analytical model has been developed to simulate the Radial Thickness of the helix employed in practical traveling wave tubes. With this proposed model, the exact physical dimensions of the helix Radial Thickness can be incorporated in the design equations. Relevant dispersion relations, characteristic and interaction impedances, and equivalent circuit parameters are derived by making use of both the field theory and equivalent analysis methods. Besides, in the field theory approach, a novel technique has been introduced to reduce the complexity in the derivation of the design formula. The results obtained using the present model are critically assessed, for four different practical slow-wave structures, over a wide range of experimental frequencies and found to be better than those obtained using earlier models.
-
An improved approach for the simulation of Radial Thickness of helix for practical TWTs
ICMMT'98. 1998 International Conference on Microwave and Millimeter Wave Technology. Proceedings (Cat. No.98EX106), 1998Co-Authors: M. V. Kartikeyan, Ashok K. Sinha, H. N. Bandopadhyay, D.s. VenkateswarluAbstract:A new approach incorporating the exact physical dimension of the helix has been proposed to simulate the Radial Thickness of the helix employed in a practical TWT. The dispersion results obtained using the present approach are applied to three different practical slow-wave structures in TWTs over a wide range of frequencies and found to be better than those obtained using earlier approaches.
K. Williams - One of the best experts on this subject based on the ideXlab platform.
-
VIBRATIONAL MODES OF THICK CYLINDERS OF FINITE LENGTH
Journal of Sound and Vibration, 1996Co-Authors: H. Wang, K. WilliamsAbstract:Abstract The natural frequencies and mode shapes of finite length thick cylinders are of considerable engineering importance. A comprehensive classification of the modes of such thick cylinders, based on three-dimentional mode shapes, is presented in this paper. In addition to the 5 groups consisting of pure Radial, Radial motion with Radial shearing, extensional, axial bending, and global modes, as previously adopted for thin cylinders, a futher sixth circumferential category is proposed. This classification, together with the numbers of both the circumferential and the longitudinal nodes, is sufficient to identify each mode of a finite length thick cylinder. The classification for the modes of thick cylinders is applied to four groups of cylinder whose Radial Thickness to median radius ratio varies from 0·1 to 0·4. Each group contains a set of 8 cylinders with similar inside and outside diameters, but with different axial lengths; these were used to verify the validity of the classifications, and to study the effects of varying axial length and varying Radial Thickness on each of the different types of modes. Analytical finite element analysis was applied to all four groups, and experimental anlysis was applied to those cylinders whose Radial Thickness to the medium radius ratio was 0·4. The results support the method of classification, although very short cylinders behave essentially as annular circular plates. The effects of varying axial length and Radial Thickness on the vibrational modes are such that all modes can be broadly categorized as either pure Radial modes, or non-pure Radial modes. The natural frequencies of the former are dependent upon only the Radial dimensions of the models, while the natural frequencies of the latter are dependent upon both axial length and Radial Thickness.
-
Effect of Radial Thickness on the In-Plane Free Vibrations of Circular Annular Discs
Journal of Vibration and Acoustics, 1991Co-Authors: R. K. Singal, K. Williams, Huan WangAbstract:In this paper the in-plane free vibrations of both thick and thin circular annular discs are studied. The well-known energy method, which is based on the three-dimensional theory of elasticity, is used in the derivation of the frequency equation of the disc. The frequency equation yields all the natural frequencies for all the circumferential modes of vibration, including the breathing and beam-type modes. In order to assess the validity of the analysis experimental data were acquired on several models. The paper first describes briefly the energy method analysis, this is followed by a description of the various experimental models. Finally, the calculated values of frequencies are compared with the experimental values. A very close agreement between both the theoretical and experimental values of the resonant frequencies for all the models was obtained and this validates the energy method of analysis.
