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Superplastic forming using NIKE3D (open access)

Superplastic forming using NIKE3D

The superplastic forming process requires careful control of strain rates in order to avoid strain localizations. A load scheduler was developed and implemented into the nonlinear finite element code NIKE3D to provide strain rate control during forming simulation and process schedule output. Often the sheets being formed in SPF are very thin such that less expensive membrane elements can be used as opposed to shell elements. A large strain membrane element was implemented into NIKE3D to assist in SPF process modeling.
Date: December 4, 1996
Creator: Puso, M.
System: The UNT Digital Library
X-Ray Emission From National Ignition Facility Indirect Drive Targets (open access)

X-Ray Emission From National Ignition Facility Indirect Drive Targets

We have performed a series of 1-D numerical simulations of the x-ray emission from National Ignition Facility (NIF) targets. Results are presented in terms of total x-ray energy, pulse length, and spectrum. Scaling of x-ray emissions is presented for variations in both target yield and hohlraum thickness. Experiments conducted on the Nova facility provide some validation of the computational tools and methods.
Date: June 4, 1996
Creator: Anderson, A. T.; Managan, R. A.; Tobin, M. T. & Peterson, P. F.
System: The UNT Digital Library
Modeling and Experiments of X-Ray Ablation of National Ignition Facility First Wall Materials (open access)

Modeling and Experiments of X-Ray Ablation of National Ignition Facility First Wall Materials

This paper discusses results of modeling and experiments on the x-ray response of selected materials relevant to NIF target chamber design. X-ray energy deposition occurs in such small characteristic depths (on the order of a micron) that thermal conduction and hydrodynamic motion significantly affect the material response, even during the typical 10-ns pulses. The finite-difference ablation model integrates four separate processes: x-ray energy deposition, heat conduction, hydrodynamics, and surface vaporization. Experiments have been conducted at the Nova laser facility in Livermore on response of various materials to NIF-relevant x-ray fluences. Fused silica, Si nitride, B carbide, B, Si carbide, C, Al2O3, and Al were tested. Response was diagnosed using post-shot examinations of the surfaces with SEM and atomic force microscopes. Judgements were made about the dominant removal mechanisms for each material; relative importances of these processes were also studied with the x-ray response model.
Date: June 4, 1996
Creator: Anderson, A. T.; Burnham, A. K.; Tobin, M. T. & Peterson, P. F.
System: The UNT Digital Library
Sheath broadening in imploding z-pinches due to large-bandwidth Rayleigh-Taylor instability (open access)

Sheath broadening in imploding z-pinches due to large-bandwidth Rayleigh-Taylor instability

The magnetic Rayleigh-Taylor (RT) instability has been predicted and observed to cause breakup of the plasma sheath in imploding Z-pinches. In this work we show that for the type of density profile encountered in strongly radiating pinches, instability at very short wavelengths grows to the non-linear stage and seeds progressively longer wavelengths. The result is a self-similar broadening of the sheath as found for mix layers in fluid RT unstable systems.
Date: June 4, 1996
Creator: Hammer, J. H.; Eddleman, J. L.; Tabak, M.; Toor, A.; Zimmerman, G. B. & De Groot, J. S.
System: The UNT Digital Library
Progress on PEP-II magnet power conversion system (open access)

Progress on PEP-II magnet power conversion system

The various power systems for supplying the PEP-II DC magnets rely exclusively on switchmode conversion, utilizing a variety of means depending on the requirements. All of the larger power supplies, ranging from 10 to 200 kW, are powered from DC sources utilizing rectified 480 V AC. Choppers can be used for the series connected strings, but for smaller groups and individual magnets, inverters driving high-frequency transformers with rectifiers comprise the best approach. All of the various systems use a ``building block`` approach of multiple standard-size units connected in series or parallel to most cost-effectively deal with a great range of voltage and current requirements. Utilization of existing infrastructure from PEP-I has been a cost-effective determinant. Equipment is being purchased either off-the-shelf, through performance specification, or by hardware purchase based on design-through-prototype. The corrector magnet power system, utilizing inexpensive, off-the-shelf, four-quadrant switching motor-controllers, has already proven very reliable: 120 of the total of 900 units have been running on the injection system for four months with no failures.
Date: June 4, 1996
Creator: Bellomo, P.; Genova, L.; Jackson, T. & Shimer, D.
System: The UNT Digital Library
Remote Viewing End Effectors for Light Duty Utility Arm Robot (U) (open access)

Remote Viewing End Effectors for Light Duty Utility Arm Robot (U)

The Robotics Development Groups at the Savannah River Site (SRS) and at the Hanford site have developed remote video and photography systems for deployment in underground radioactive-waste storage tanks at the Department of Energy (DOE) sites as a part of the Office of Science and Technology (OST) program within DOE. Viewing and documenting the tank interiors and their associated annular spaces is an extremely valuable tool in characterizing their condition and contents and in controlling their remediation. Several specialized video/photography systems and robotic End Effectors have been fabricated that provide remote viewing and lighting. All are remotely deployable into and out of the tank, with all viewing functions remotely operated. Positioning all control components away from the facility prevents the potential for personnel exposure to radiation and contamination. Only the remote video systems are discussed in this paper.
Date: November 4, 1996
Creator: Heckendorn, F. M.; Robinson, C. W.; Haynes, H. B.; Anderosn, E. K. & Pardini, A. F.
System: The UNT Digital Library
CONCLUSIONS OF THE WORKSHOP [Hadron Colliders at the highest energy and luminosity] (open access)

CONCLUSIONS OF THE WORKSHOP [Hadron Colliders at the highest energy and luminosity]

During this Workshop, it was concluded that a Proton-Proton Collider with an energy of 100 TeV per beam and a luminosity of about 10{sup 35} cm{sup {minus}2} s{sup {minus}1} is feasible. The most important technical requirement for the realization of such a project is a large bending field. For instance, a field of 13 Tesla would be desirable. This is twice the field of the SSC superconducting magnets, which very likely may be achieved in a non-too-far future by extrapolation of the present technology. The design of this Collider would follow very closely the methods used for the design of the SSC and of the LHC, with the major noticeable difference that, because of the larger bending field and the larger beam energy, the performance is determined by the effects of the Synchrotron Radiation in the similar manner they affect the performance of an electron-positron collider. This fact has considerable beneficial consequences since it allows the attainment of large luminosity by reducing the beam dimensions at collision and by requiring, to some degree, less number of particles per beam. On the other end. the losses to synchrotron radiation are to be absorbed by the cryogenic system, and the vacuum system …
Date: November 4, 1996
Creator: Ruggiero, Alessandro G.
System: The UNT Digital Library
Design Considerations and Expectations of a Very Large Hadron Collider (open access)

Design Considerations and Expectations of a Very Large Hadron Collider

The ELOISATRON Project is a proton-proton collider at very high energy and very large luminosity. The main goal is to determine the ultimate performance that is possible to achieve with reasonable extrapolation of the present accelerator technology. A complete study and design of the collider requires that several steps of investigations are undertaken. The authors count five of such steps as outlined in the report.
Date: November 4, 1996
Creator: Ruggiero, A. G.
System: The UNT Digital Library
Compendium of Equations for the Design of a Very Large Hadron Collider (open access)

Compendium of Equations for the Design of a Very Large Hadron Collider

In the following the authors give several relationships which are used for the preliminary design and to estimate the collider performance. They limit to the case of the performance during storage and colliding mode. Two of such relations are the relation between bending field B, the bending radius {rho} and the proton momentum p B (Tesla) {rho} (meter) = 3.3356 p (GeV/c) and the minimum requirement of the collider luminosity L which scales with the beam energy E according to L = (10{sup 33} cm{sup {minus}2} s{sup {minus}1}) (E/20 TeV ). They assume that the collider is made of two identical intersecting rings where the two beams circulate in opposite directions otherwise with identical configuration, dimensions and intensity. Both beams are bunched. They also assume, for simplicity, that the beams are round, that is they have the same betatron emittance in the two transverse planes of oscillations, horizontal and vertical. Also the two beams are exactly round at the interaction point where the lattice functions {beta}* has also the same values in the two planes.
Date: November 4, 1996
Creator: RUGGIERO, A. G.
System: The UNT Digital Library
Trading Studies of a Very Large Hadron Collider (open access)

Trading Studies of a Very Large Hadron Collider

The authors have shown that the design of the ELOISATRON can be approached in five separate steps. In this report they deal with the two major issues of the collider: the size and the strength of the superconducting magnets. The reference design of the SSC calls for a collider circumference of 86 km. It represents the largest size that until recently was judged feasible. The reference design of the LHC requires a bending field of 9 Tesla, that industries are presently determined to demonstrate. Clearly the large size of the project presents problem with magnet tolerances, and collider operation and management. The high field of the superconducting magnets needs to be demonstrated, and the high-field option in excess of 9 Tesla requires extensive research and development. It is obvious from the start that, if the ELOISATRON has to allow large beam energies, the circumference has also to be larger than that of the SSC, probably of few hundred kilometers. On the other end, Tevatron, RHIC and SSC type of superconducting magnets have been built and demonstrated on a large scale and proven to be cost effective and reliable. Their field, nevertheless, hardly can exceed a value of 7.5 Tesla, without …
Date: November 4, 1996
Creator: Ruggiero, A. G.
System: The UNT Digital Library
Phase shifting diffraction interferometry for measuring extreme ultraviolet optics (open access)

Phase shifting diffraction interferometry for measuring extreme ultraviolet optics

Extreme ultraviolet projection lithography operating at a wavelength of 13nm requires surface figure accuracy on each mirror to be better than 0.25nm rms. A new type of interferometry, based on the fundamental process of diffraction, is described that can intrinsically achieve the required accuracy. Applying this principle, two independent spherical wavefronts are generated - one serves as the measurement wavefront and is incident on the optic or optical system under test and the other serves as the reference wavefront. Since they are generated independently their relative amplitude and phase can be controlled, providing contrast adjustment and phase shifting capability. Using diffraction from a single mode optical fiber, different interferometers can be configured to measure individual mirrors or entire imaging systems. Measurement of an EUV projection system is described. 5 refs., 4 figs.
Date: June 4, 1996
Creator: Sommargren, G.E.
System: The UNT Digital Library
Open architecture controller activities in TEAM (open access)

Open architecture controller activities in TEAM

As part of its manufacturing initiative, TEAM is actively involved in open architecture controller activities. Within the TEAM community of members, TEAM is developing an open architecture controller requirements document and an open architecture controller application programming interface document. In addition, TEAM is also evaluating early open architecture controllers in a shop floor environment.
Date: February 4, 1996
Creator: McCue, H.K.
System: The UNT Digital Library
Fracture Toughness and Impact Properties of Laminated Metal Composites (open access)

Fracture Toughness and Impact Properties of Laminated Metal Composites

Laminated metal composites consist of alternating metal (or metal matrix composite) layers bonded together. These materials can provide fracture toughness and impact properties superior to those of the component materials. These properties are a function of component material properties, laminate architecture (volume fraction, thickness) and interface properties. Properties are compared for seven lightweight materials.
Date: March 4, 1996
Creator: Lesuer, Donald R.; Riddle, Robert A.; Gogolewski, Ramond P.; Syn, Chol K. & Cunningham, Bruce J.
System: The UNT Digital Library
A unique data acquisition system for electrical resistance tomography (open access)

A unique data acquisition system for electrical resistance tomography

Unique capabilities are needed in instrumentation used for acquiring data to do electrical resistance tomography (ERT). A data acquisition system is described which has a good combination of the required capabilities and yet is field rugged and user friendly. The system is a multichannel detector for high data rates, can operate over a wide range of load conditions, will measure both in phase and quadrature resistance at frequencies between 0.0007 Hz and 8 kHz. The system has been used in both the field and laboratory to collect data with a typical accuracy between 1 and 10%.
Date: January 4, 1996
Creator: Daily, W.; Ramirez, A. & Zonge, K.
System: The UNT Digital Library
Five-beam Fabry-Perot velocimeter (open access)

Five-beam Fabry-Perot velocimeter

Velocimetry is useful in diagnosing many properties of high-explosive (HE) systems. The shock pressure of the detonation wave in HE is often measured by noting the velocity of an interface between the HE and a known material. Properties of the equation of state (EOS) of an explosive can be measured in a cylinder event using a combination of velocimetry and other diagnostics. Point-initiated explosions driving large plates give additional information regarding HE EOS. Hemispherical booster shots give quantitative data pertaining to booster performance. Velocimetry is used routinely to measure the performance of detonators. Velocimetry will be a particularly effective tool in cylinder shots, flat plate, and booster shots to determine the effects of aging on the EOS of explosive components in stockpile devices.
Date: March 4, 1996
Creator: Druce, R.L.; Goosman, D.G. & Collins, L.F.
System: The UNT Digital Library
Process engineering using object management simulation tools (open access)

Process engineering using object management simulation tools

Poised to enter the twenty-first century, we experiencing profound changes in all aspects of our life including business, science, and home life. It is an exciting time for quality professionals, however it is also time for learning new techniques and tools. The working world is embracing computers to address increasingly complex systems. Changes are reflected in quality and management literature through discussions on process management, sophisticated automation, business process re-engineering, etc. Although the concepts and techniques may differ, they have the same objective, that is, to achieve the best possible organizational structures amid rapid changes. Recent advances in system engineering launched the powerful object management paradigm. Initially implemented in the software engineering world, this methodology is making its way into the business world. A new breed of simulation tools supporting it is now affordable. In this paper, use of these tools will be explored with real life examples.
Date: April 4, 1996
Creator: Banerjee, B.
System: The UNT Digital Library
Calculations of slurry pump jet impingement loads (open access)

Calculations of slurry pump jet impingement loads

This paper presents a methodology to calculate the impingement load in the region of a submerged turbulent jet where a potential core exits and the jet is not fully developed. The profile of the jet flow velocities is represented by a piece-wise linear function which satisfies the conservation of momentum flux of the jet flow. The adequacy of the of the predicted jet expansion is further verified by considering the continuity of the jet flow from the region of potential core to the fully developed region. The jet impingement load can be calculated either as a direct impingement force or a drag force using the jet velocity field determined by the methodology presented.
Date: March 4, 1996
Creator: Wu, T. T.
System: The UNT Digital Library
Parton distributions from SMC and SLAC data (open access)

Parton distributions from SMC and SLAC data

We have extracted spin-weighted parton distributions in a proton from recent data at CERN and SLAC. The valence, sea quark and Antiquark spin-weighted distributions are determined separately. The data are all consistent with a small to moderate polarized gluon distribution, so that the anomaly term is not significant in the determination of the constituent contributions to the spin of the proton. We have analyzed the consistency of the results obtained from various sets of data and the Biorken sum rule. Although all data are consistent with the sum rule, the polarized distributions from different experiments vary, even with higher order QCD corrections taken into account. Results split into two models, one set implying a large polarized strange sea which violates the positivity bound, and the other set yielding a smaller polarized strange sea. Only further experiments which extract information about the polarized sea will reconcile these differences. We suggest specific experiments which can be performed to determine the size of the polarized sea and gluons.
Date: January 4, 1996
Creator: Ramsey, G. P. & Goshtasbpour, M.
System: The UNT Digital Library
Industrial ecology at Lawrence Livermore National Laboratory summary statement (open access)

Industrial ecology at Lawrence Livermore National Laboratory summary statement

At Livermore our hope and our intention is to make important contributions to global sustainability by basing both our scientific and technological research and our business practices on the principles of industrial ecology. Current efforts in the following fields are documented: global security, global ecology, energy for transportation, fusion energy, materials sciences, environmental technology, and bioscience.
Date: June 4, 1996
Creator: Gilmartin, T. J.
System: The UNT Digital Library