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3. 6 simplified methods for design
Simplified design analysis methods for elevated temperature construction are classified and reviewed. Because the major impetus for developing elevated temperature design methodology during the past ten years has been the LMFBR program, considerable emphasis is placed upon results from this source. The operating characteristics of the LMFBR are such that cycles of severe transient thermal stresses can be interspersed with normal elevated temperature operational periods of significant duration, leading to a combination of plastic and creep deformation. The various simplified methods are organized into two general categories, depending upon whether it is the material, or constitutive, model that is reduced, or the geometric modeling that is simplified. Because the elastic representation of material behavior is so prevalent, an entire section is devoted to elastic analysis methods. Finally, the validation of the simplified procedures is discussed.
Date:
January 1, 1981
Creator:
Nickell, R.E. & Yahr, G.T.
System:
The UNT Digital Library
3.9 GHz superconducting accelerating 9-cell cavity vertical test results
The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the FLASH (TTF/DESY) facility [1]. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first 9-cell Nb cavities were tested in a vertical setup and they didn't reach the designed accelerating gradient [2]. The main problem was a multipactor in the HOM couplers, which lead to overheating and quenching of the HOM couplers. New HOM couplers with improved design are integrated in the next 9-cell cavities. In this paper we present all results of the vertical tests.
Date:
June 1, 2007
Creator:
Khabiboulline, Timergali; Cooper, Charles; Dhanaraj, Nandhini; Edwards, Helen; Foley, Mike; Harms, Elvin et al.
System:
The UNT Digital Library
3.9 GHz superconducting accelerating 9-cell cavity vertical test results
None
Date:
June 1, 2007
Creator:
Khabiboulline, Timergali; Cooper, Charles; Dhanaraj, Nandhini; Edwards, Helen; Foley, Mike; Harms, Elvin et al.
System:
The UNT Digital Library
3-10 keV and 0. 1- to 2-MeV observations of four gamma-ray bursts
Four catalogued ..gamma..-ray bursts that occurred between 79/3/7 and 79/7/31 have been observed over the 3 to 10 keV range by a joint NRL/Los Alamos experiment on the Air Force P78-1 satellite. The bursts were also well observed by members of the interplanetary network. In this paper we present hardness ratios, x-ray/..gamma..-ray luminosity ratios, and time histories. The most significant results presented herein can be summarized as follows: (1) gamma-ray bursters can emit fairly strongly at x-ray energies near the time of the ..gamma.. burst with L/sub x//L/sub ..gamma../ approx. .02 (L/sub x/ approx. 10/sup 37/ ergs s/sup -1/, 3 to 10 keV, assuming a distance of 1 kpc); (2) the centroid of the x-ray emission generally lags the ..gamma..-ray centroid, but there is also evidence for one or more types of x-ray precursor activity; (3) the ..gamma..-ray hardness ratios were not highly variable for these particular events. However, there is some evidence that the ..gamma..-ray spectra softened near the ends of the bursts when the x-ray/..gamma..-ray ratios were high; (4) the x-ray/..gamma..-ray power law number index during times of the strongest ..gamma..-ray emission ranged from 0.8 to approx. 1.1 for the four bursts; (5) the x-ray tail of GB790307 …
Date:
January 1, 1983
Creator:
Laros, J. G.; Evans, W. D.; Fenimore, E. E.; Klebesadel, R. W.; Shulman, S. & Fritz, G.
System:
The UNT Digital Library
A 3-Axis Force Balanced Accelerometer Using a Single Proof-Mass
This paper presents a new method for wideband force balancing a proof-mass in multiple axes simultaneously. Capacitive position sense and force feedback are accomplished using the same air-gap capacitors through time multiplexing. Proof of concept is experimentally demonstrated with a single-mass monolithic surface micromachined 3-axis accelerometer.
Date:
April 1997
Creator:
Lemkin, M.A.; Boser, B.E.; Auslander, D. & Smith, J.
System:
The UNT Digital Library
3-body final states in peripheral heavy-ion collisions: nuclear clustering structure and projectile excitation revisited
Even though peripheral heavy-ion collisions are less violent than their central counterparts, the large energy exchange between the reactants often leaves the primary products in excited particle-unstable states whose subsequent decay leads to 3 or more nuclei emerging in the final exit channel. These post-reaction, predominantly sequential de-excitation processes can sometimes provide interesting structural information about the parent nuclei. In fact, provided these processes are well understood, one can employ them as probes for studying initial properties of the fragments. This report discusses results of two experiments that deal with (1) nonstatistical, rare decay modes of the projectile, and (2) internal excitation energy of the projectile- and target-like fragments in peripheral collisions. The physics addressed in each is different, but the experimental and data-analysis techniques are so similar that it is relevant to join them together.
Date:
February 1, 1986
Creator:
Chan, Y.; Chavez, E.; Gazes, S.B.; Kamermans, R.; Schmidt, H.R.; Siwek-Wilczynska, J. et al.
System:
The UNT Digital Library
3-Center-4-Electron Bonding in [(silox)2Mo=NtBu]2(μ-Hg) Controls Reactivity while Frontier Orbitals Permit a Dimolybdenum π-Bond Energy Estimate
Article describing research on 3-center-4-electron bonding in [(silox)2Mo=NtBu]2(mu-Hg).
Date:
May 18, 2005
Creator:
Rosenfeld, Devon C.; Wolczanski, Peter T.; Barakat, Khaldoon A.; Buda, Corneliu & Cundari, Thomas R., 1964-
System:
The UNT Digital Library
A 3-D adaptive mesh refinement algorithm for multimaterial gas dynamics
Adaptive Mesh Refinement (AMR) in conjunction with high order upwind finite difference methods has been used effectively on a variety of problems. In this paper we discuss an implementation of an AMR finite difference method that solves the equations of gas dynamics with two material species in three dimensions. An equation for the evolution of volume fractions augments the gas dynamics system. The material interface is preserved and tracked from the volume fractions using a piecewise linear reconstruction technique. 14 refs., 4 figs.
Date:
August 12, 1991
Creator:
Puckett, E. G. & Saltzman, J. S.
System:
The UNT Digital Library
3-D Analysis on Arbitrarily-Shaped Icrf Antennas and Faraday Shields
Cavity antennas with Faraday shields are proposed to couple ion cyclotron radio frequency power for heating fusion plasmas. This application requires small, high-power, low-frequency antennas. The results are presented of a theoretical study of the ICRF antennas being developed for this purpose at the Radio Frequency Test Facility (RFTF). The objectives of this work are to optimize experimental designs and to confirm test results. (MOW)
Date:
January 1, 1986
Creator:
Chen, G. L.; Whealton, J. H.; Baity, F. W.; Hoffman, D. J. & Owens, T. L.
System:
The UNT Digital Library
3-D Combinatorial Geometry in the MERCURY Monte Carlo Particle Transport Code
Lawrence Livermore National Laboratory is in the process of developing a new Monte Carlo Particle Transport code named MERCURY. This new code features a 3-D Combinatorial Geometry tracking algorithm. This paper details some of the characteristics of this Monte Carlo tracker
Date:
September 27, 2004
Creator:
Greenman, G
System:
The UNT Digital Library
3-D Computations and Measurements of Accelerator Magnets for the APS
The Advanced Photon Source (APS), now under construction at Argonne National Laboratory (ANL), requires dipole, quadrupole, sextupole, and corrector magnets for each of its circular accelerator systems. Three-dimensional (3-D) field computations are needed to eliminate unwanted multipole fields from the ends of long quadrupole and dipole magnets and to guarantee that the flux levels in the poles of short magnets will not cause saturation. Measurements of the magnets show good agreement with the computations.
Date:
1993-11~
Creator:
Turner, L. R.; Kim, S. H. & Kim, K.
System:
The UNT Digital Library
3-D DETERMINISTIC TRANSPORT METHODS RESEARCH AT LANL UNDER ASCI
None
Date:
January 1, 2000
Creator:
Morel, J.
System:
The UNT Digital Library
A 3-D dynamical/chemical GCM for simulating the anthropogenical effects on ozone
In spite of the significantly increased attention atmospheric ozone has received over the last two decades or so, a fully quantitative understanding of the three-dimensional ozone structure remains unavailable. In the past, one-dimensional (vertical column) models have provided most of the quantitative simulations of atmospheric chemical systems, because these models can treat large ensembles of chemical process economically. More recently, two-dimensional (meridional cross section) models have become popular, in part because of increasing computer capabilities. There has been little work using a sophisticated 3-D GCM coupled with a comprehensive photochemical model to study the chemical-dynamical interactions involving the ozone abundance. Namely, either the dynamics or the chemistry is too simplified in most of the existing models. Relatively more advanced photochemistry has been included in the stratospheric models (dealing the vertical domain from 20 to 70 km above the surface) at the expense of tropospheric details. An important motivation for this research has been the desire to estimate the magnitude of changes in the ozone layer induced by anthropogenic perturbations such as the injection of oxides of nitrogen and chlorine compounds. Accordingly, the attempt has been to develop a complete but feasible photochemical scheme and to combine it with the Los …
Date:
January 1, 1989
Creator:
Kao, C. Y. J.; Glatzmaier, G. A.; Malone, R. C. & Turco, R. P.
System:
The UNT Digital Library
3-D elastic wave scattering by a layer containing vertical periodic fractures
None
Date:
April 30, 2002
Creator:
Nakagawa, Seiji; Nihei, Kurt T.; Myer, Larry R. & Majer, Ernest L.
System:
The UNT Digital Library
3-D electromagnetic modeling of wakefields in accelerator components
We discuss the use of 3-D finite-difference time-domain (FDTD) electromagnetic codes for modeling accelerator components. Computational modeling of cylindrically symmetric structures such as induction accelerator cells has been very successful in predicting the wake potential and wake impedances of these structures, but full 3-D modeling of complex structures has been limited due to substantial computer resources required for a full 3-D model. New massively parallel 3-D time domain electromagnetic codes now under development using conforming unstructured meshes allow a substantial increase in the geometric fidelity of the structures being modeled. Development of these new codes are discussed in context of applicability to accelerator problems. Various 3-D structures are tested with an existing cubical cell FDTD code and wake impedances compared with simple analytic models for the structures; results will be used as benchmarks for testing the new time time domain codes. Structures under consideration include a stripline beam position monitor as well as circular and elliptical apertures in circular waveguides. Excellent agreement for monopole and dipole impedances with models were found for these structures below the cutoff frequency of the beam line.
Date:
September 18, 1996
Creator:
Poole, B.R.; Caporaso, G.J.; Ng, Wang C.; Shang, C.C. & Steich, D.
System:
The UNT Digital Library
3-D field computation: The near-triumph of commerical codes
In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.
Date:
July 1995
Creator:
Turner, L. R.
System:
The UNT Digital Library
3-D Field Computations for Accelerator Magnets Using Finite Element and Integral Codes
Two dimensional (2-D) computation has been an accepted part of the design of accelerator magnets since the 1960's, but three-dimensional (3-D) computations are still not fully trusted. This paper describes the successes and limitations of 3-D computations, as applied to accelerator magnets for the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Both the finite element code TOSCA and the edge element volume integral code CORAL have been used in these computations. The ends of the dipole bending magnet for the injector synchrotron were designed using TOSCA; comparisons with measurements are described. Computation of other APS magnets are also described.
Date:
1992~
Creator:
Turner, L. R.; Kim, S. H.; Kim, K. & Kettunen, L.
System:
The UNT Digital Library
3-D field computations for accelerator magnets using finite element and integral codes
Two dimensional (2-D) computation has been an accepted part of the design of accelerator magnets since the 1960`s, but three-dimensional (3-D) computations are still not fully trusted. This paper describes the successes and limitations of 3-D computations, as applied to accelerator magnets for the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Both the finite element code TOSCA and the edge element volume integral code CORAL have been used in these computations. The ends of the dipole bending magnet for the injector synchrotron were designed using TOSCA; comparisons with measurements are described. Computation of other APS magnets are also described.
Date:
December 1, 1992
Creator:
Turner, L. R.; Kim, S. H.; Kim, K. & Kettunen, L.
System:
The UNT Digital Library
3-D Finite Element Analysis of Induction Logging in a Dipping Formation
Electromagnetic induction by a magnetic dipole located above a dipping interface is of relevance to the petroleum well-logging industry. The problem is fully three-dimensional (3-D) when formulated as above, but reduces to an analytically tractable one-dimensional (1-D) problem when cast as a small tilted coil above a horizontal interface. The two problems are related by a simple coordinate rotation. An examination of the induced eddy currents and the electric charge accumulation at the interface help to explain the inductive and polarization effects commonly observed in induction logs from dipping geological formations. The equivalence between the 1-D and 3-D formulations of the problem enables the validation of a previously published finite element solver for 3-D controlled-source electromagnetic induction.
Date:
July 20, 2000
Creator:
Everett, Mark E.; Badea, Eugene A,; Shen, Liang, C.; Merchant, Gulamabbas A. & Weiss, Chester J.
System:
The UNT Digital Library
3-d finite element model development for biomechanics: a software demonstration
Finite element analysis is becoming an increasingly important part of biomechanics and orthopedic research, as computational resources become more powerful, and data handling algorithms become more sophisticated. Until recently, tools with sufficient power did not exist or were not accessible to adequately model complicated, three-dimensional, nonlinear biomechanical systems. In the past, finite element analyses in biomechanics have often been limited to two-dimensional approaches, linear analyses, or simulations of single tissue types. Today, we have the resources to model fully three-dimensional, nonlinear, multi-tissue, and even multi-joint systems. The authors will present the process of developing these kinds of finite element models, using human hand and knee examples, and will demonstrate their software tools.
Date:
March 1, 1997
Creator:
Hollerbach, K.; Hollister, A.M. & Ashby, E.
System:
The UNT Digital Library
3-D full waveform inversion of seismic data; Part I. Theory
Full waveform inversion of seismic data is a challenging subject partly because of the lack of precise knowledge of the source. Since currently available approaches involve some form of approximations to the source, inversion results are subject to the quality and the choice of the source information used. A new full waveform inversion scheme has been introduced (Lee and Kim, 2003) using normalized wavefield for simple two-dimensional (2-D) scalar problems. The method does not require source information, so potential inversion errors due to source estimation may be eliminated. A gather of seismic traces is first Fourier-transformed into the frequency domain and a normalized wavefield is obtained for each trace in the frequency domain. Normalization is done with respect to the frequency response of a reference trace selected from the gather, so the complex-valued normalized wavefield is source-independent and dimensionless. The inversion algorithm minimizes misfits between measured normalized wavefield and numerically computed normalized wavefield. In this paper the full waveform inversion is extended to three-dimensional (3-D) problems.
Date:
May 12, 2003
Creator:
Lee, Ki Ha
System:
The UNT Digital Library
3-D heat transfer computer calculations of the performance of the IAEA's air-bath calorimeters
A three dimensional (3-D) heat transfer computer code was developed to study and optimize the design parameters and to better understand the performance characteristics of the IAEA's air-bath calorimeters. The computer model accounts for heat conduction and radiation in the complex materials of the calorimeter and for heat convection and radiation at its outer surface. The temperature servo controller is modelled as an integral part of the heat balance equations in the system. The model predictions will be validated against test data using the ANL bulk calorimeter. 11 refs., 6 figs.
Date:
January 1, 1989
Creator:
Elias, E.; Kaizermann, S.; Perry, R. B. & Fiarman, S.
System:
The UNT Digital Library
3-D hybrid PIC code to model the tilt mode in FRCs
The results from QN3D are presented. QN3D is a 3-dimensional hybrid particle-in-cell code designed to run efficiently on the Cray-2 Multiprocessor. The chief application has been to the tilt mode instability in FRCs. QN3D accepts as input, the magnetic field, the ion particle density and the ion temperature on a two-dimensional r-z grid. These quantities are interpolated to the rest of the cartesian grid under the assumption of azimuthal symmetry. The particles are initialized with random numbers chosen according to the particle distributions input from the equilibrium code. The runs done here used equilibria computed by EQV, a kinetic equilibrium code.
Date:
June 1, 1987
Creator:
Horowitz, E. J. & Shumaker, D. E.
System:
The UNT Digital Library
A 3-D hydrodynamic dispersion model for modeling tracer transport in Geothermal Reservoirs
A 3-D hydrodynamic dispersion model for tracer transport is developed and implemented into the TOUGH2 EOS3 (T2R3D) module. The model formulation incorporates a full dispersion tensor, based on a 3-D velocity field with a 3-D, irregular grid in a heterogeneous geological system. Two different weighting schemes are proposed for spatial average of 3-D velocity fields and concentration gradients to evaluate the mass flux by dispersion and diffusion of a tracer or a radionuclide. This new module of the TOUGH2 code is designed to simulate processes of tracer/radionuclide transport using an irregular, 3-D integral finite difference grid in non-isothermal, three-dimensional, multiphase, porous/fractured subsurface systems. The numerical method for this transport module is based on the integral finite difference scheme, as in the TOUGH2 code. The major assumptions of the tracer transport module are: (a) a tracer or a radionuclide is present and transported only within the liquid phase, (b) transport mechanisms include molecular diffusion and hydrodynamic dispersion in the liquid phase in addition to advection, and (c) first order decay and linear adsorption on rock grains are taken into account. The tracer or radionuclide is introduced as an additional mass component into the standard TOUGH2 formulation, time is discretized fully implicitly, …
Date:
January 26, 1998
Creator:
Wu, Yu-Shu & Pruess, Karsten
System:
The UNT Digital Library