427 Matching Results

Search Results

Results: 1 - 24 next
open access

Ion Desorption Stability in Superconducting High Energy Physics Proton Colliders

Description: In this paper we extend our previous analysis of cold beam tube vacuum in a superconducting proton collider to include ion desorption in addition to thermal desorption and synchrotron radiation induced photodesorption. The new ion desorption terms introduce the possibility of vacuum instability. This is similar to the classical room temperature case but now modified by the inclusion of ion desorption coefficients for cryosorbed (physisorbed) molecules which can greatly exceed the coefficients f… more
Date: May 29, 1995
Creator: Turner, W.C.
Partner: UNT Libraries Government Documents Department
open access

Volatile N-nitrosamines in Environment Tobacco Smoke: Sampling,Analysis, Smission Factors, and Indoor Air Exposures

Description: A more convenient sampling and analysis method for the volatile N-nitrosamines (VNA) in ETS, using commercially available TherrnosorbIN cartridges, was developed and validated. Using the method, emission factors for the two major VNA in environmental tobacco smoke (ETS) were determined in a room-sized environmental chamber for six commercial cigarette brands, which together accounted for 62.5% of the total market in California in 1990. The average emission factors were 565 {+-} 115 and 104 {+-}… more
Date: May 1, 1995
Creator: Mahanama, K. R. R. & Daisey, J. M.
Partner: UNT Libraries Government Documents Department
open access

A lightweight high performance dual-axis gimbal for space applications

Description: This paper describes the design, development and performance of a lightweight precision gimbal with dual-axis slew capability to be used in a closed-loop optical tracking system at Lawrence Livermore National Laboratory-LLNL. The motivation for the development of this gimbal originates from the need to acquire and accurately localize warm objects (T{approximately}500 K) in a cluttered background. The design of the gimbal is centered around meeting the following performance requirements: pointin… more
Date: May 5, 1995
Creator: Pines, D. J.; Hakala, D. B. & Malueg, R.
Partner: UNT Libraries Government Documents Department
open access

Universal requisition for waste data collection

Description: Lawrence Livermore National Laboratory (LLNL) has developed a data management tool for information gathering that encompasses all types of waste generated by the site. It is referred to as the Universal Requisition. It can be used to record information for the following types of waste: non-hazardous, hazardous, low level radioactive, mixed, transuranic (TRU), and TRU mixed wastestreams. It provides the salient information needed for the safe handling, storage, and disposal of waste, and satisfi… more
Date: May 1995
Creator: Nisbet, B. & Gage, M.
Partner: UNT Libraries Government Documents Department
open access

A computational method for comparing the behavior and possible failure of prosthetic implants

Description: Prosthetic joint implants currently in use exhibit high Realistic computer modeling of prosthetic implants provides an opportunity for orthopedic biomechanics researchers and physicians to understand possible in vivo failure modes, without having to resort to lengthy and costly clinical trials. The research presented here is part of a larger effort to develop realistic models of implanted joint prostheses. The example used here is the thumb carpo-metacarpal (cmc) joint. The work, however, can b… more
Date: May 1, 1995
Creator: Nielsen, C.; Hollerbach, K.; Perfect, S. & Underhill, K.
Partner: UNT Libraries Government Documents Department
open access

Methodological issues in the validation of complex human-machine systems

Description: Integrated system validation is one aspect of the US Nuclear Regulatory Commission`s design review process for human-system interfaces. This paper will consider three methodological issues that must be addressed in validation and their implications for drawing conclusions about the acceptability of the integrated system. They are: representing the integrated system, representing the operational events it must handle, and representing system performance. A logical basis for generalizability from… more
Date: May 1, 1995
Creator: O`Hara, J.; Stubler, W. & Wachtel, J.
Partner: UNT Libraries Government Documents Department
open access

PEP-III magnet power conversion systems: Power supplies for large magnet strings

Description: This paper presents the cooperative design efforts of LBL, SLAC, and LLNL on the magnet power conversion systems for PEP-II. The systems include 900 channels of correction magnet bipolar supplies and 400 unipolar supplies in the range of 5 to 500 kW. We show the decision process and technical considerations influencing the choice of power supply technologies employed. We also show the development of specifications that take maximum advantage of both the resources available and existing faciliti… more
Date: May 1, 1995
Creator: Jackson, T.; Saab, A. & Shimer, D.
Partner: UNT Libraries Government Documents Department
open access

Biochemical technology for the detoxification of geothermal brines and the recovery of trace metals

Description: Studies conducted at BNL, have shown that a cost-efficient and environmentally acceptable biochemical technology for detoxification of geothermal sludges is most satisfactory, as well as technically achievable. This technology is based on biochemical reactions by which certain extremophilic microorganisms interact with inorganic matrices of geothermal origin. The biochemical treatment of wastes generated by power plants using geothermal energy is a versatile technology adaptable to several appl… more
Date: May 1, 1995
Creator: Premuzic, E.T.; Lin, M.S. & Lian, Hsienjen
Partner: UNT Libraries Government Documents Department
open access

Determination of modal residues and residual flexibility for time-domain system realization

Description: A linear least-squares procedure for the determination of modal residues using time-domain system realization theory is presented. The present procedure is shown to be theoretically equivalent to residue determination in realization algorithms such as the Eigensystem Realization Algorithm (ERA) and Q-Markov COVER. However, isolating the optimal residue estimation problem from the general realization problem affords several advantages over standard realization algorithms for structural dynamics … more
Date: May 1, 1995
Creator: Alvin, K. F. & Peterson, L. D.
Partner: UNT Libraries Government Documents Department
open access

The Speciation of Groundwater Contaminated with Coal Pile Leachate at the Savannah River Site, South Carolina

Description: Modeling the transport of contaminant metals and designing systems for their remediation requires an understanding of the metal`s speciation. Thus, analysis of contaminant speciation and evaluation of the processes that can change the speciation should be done during characterization of the contaminated site. This approach is being used at the Savannah River Site for a metals contaminated site that will serve as a test platform for metals remediation technologies. The site is adjacent to a coal… more
Date: May 15, 1995
Creator: Denham, M. E. & Nichols, R. L.
Partner: UNT Libraries Government Documents Department
open access

Computer modeling of electrical performance of detonators

Description: An empirical model of detonator electrical performance which describes the resistance of the exploding bridgewire (EBW) or exploding foil initiator (EFI or slapper) as a function of energy, deposition will be described. This model features many parameters that can be adjusted to obtain a close fit to experimental data. This has been demonstrated using recent experimental data taken with the cable discharge system located at Sandia National Laboratories. This paper will be a continuation of the … more
Date: May 1, 1995
Creator: Furnberg, C.M.; Peevy, G.R.; Brigham, W.P. & Lyons, G.R.
Partner: UNT Libraries Government Documents Department
open access

Hydrogen program combustion research: Three dimensional computational modeling

Description: We have significantly increased our computational modeling capability by the addition of a vertical valve model in KIVA-3, code used internationally for engine design. In this report the implementation and application of the valve model is described. The model is shown to reproduce the experimentally verified intake flow problem examined by Hessel. Furthermore, the sensitivity and performance of the model is examined for the geometry and conditions of the hydrogen-fueled Onan engine in developm… more
Date: May 1, 1995
Creator: Johnson, N. L.; Amsden, A. A. & Butler, T. D.
Partner: UNT Libraries Government Documents Department
open access

Quench antennas for RHIC quadrupole magnets

Description: Quench antennas for RHIC quadrupole magnets are being developed jointly by KEK and BNL. A quench antenna is a device to localize a quench origin using arrays of pick-up coils lined up along the magnet bore. Each array contains four pick-up coils: sensitive to normal sextupole, skew sextupole, normal octupole, and skew octupole field. This array configuration allows an azimuthal localization of a quench front while a series of arrays gives an axial localization and a quench propagation velocity.… more
Date: May 1, 1995
Creator: Ogitsu, T.; Terashima, A.; Tsuchiya, K.; Ganetis, G.; Muratore, J. & Wanderer, P.
Partner: UNT Libraries Government Documents Department
open access

Flat panel planar optic display. Revision 4/95

Description: A prototype 10 inch flat panel Planar Optic display, (POD), screen has been constructed and tested. This display screen is comprised of hundreds of planar optic glass sheets bonded together with a cladding layer between each sheet where each glass sheet represents a vertical line of resolution. The display is 9 inches wide by 5 inches high and approximately 1 inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.
Date: May 1, 1995
Creator: Veligdan, J.T.
Partner: UNT Libraries Government Documents Department
open access

Alignment and survey of the elements in RHIC

Description: The Relativistic Heavy Ion Collider (RHIC) consists of two rings with cryogenic magnets at a 4.5K operating temperature. Control of positions of the dipole and quadrupole cold masses (iron laminations) and the beam position monitors (BPM`s) during production and installation is presented. The roll of the dipoles is controlled by a combination of rotating coil measurements with the surveying measurements. The center of the quadrupole magnetic field is obtained by direct measurement of the field … more
Date: May 1, 1995
Creator: Trbojevic, D.; Cameron, P. & Ganetis, G. L.
Partner: UNT Libraries Government Documents Department
open access

Modeling the dynamic crush of impact mitigating materials

Description: Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence t… more
Date: May 12, 1995
Creator: Logan, R.W. & McMichael, L.D.
Partner: UNT Libraries Government Documents Department
open access

A diethyl phosphonate containing oxazoline: Synthesis and characterization of monomer and homopolymer

Description: A diethyl phosphonate oxazoline monomer and its polymer have been synthesized. The monomer appears to polymerize via a ring-opening mechanism giving the expected polyethyleneimine backbone with pendant carbonyl groups. Two distinct molecular weights were produced during polymerization suggesting two mechanisms of chain growth. Studies are underway to elucidate the reasons for this. This polymer has potential as a metal-chelating agent.
Date: May 1, 1995
Creator: Hermes, R.E.; Thompson, R.D. & Valdez, L.S.
Partner: UNT Libraries Government Documents Department
open access

Recent progress on beam stability study in the PSR

Description: A fast transverse instability has been observed in the Los Alamos Proton Storage Ring (PSR) when the injected beam intensity reaches more than 2 {times} 10{sup 13} protons per pulse. Understanding the cause and control of this instability has taken on new importance as the neutron-scattering community considers the next generation of accelerator-driven spallation-neutron sources, which call for peak-proton intensities of 10{sup 14} per pulse or higher. Previous observations and theoretical stud… more
Date: May 1, 1995
Creator: Wang, T.; Channell, P. & Cooper, R.
Partner: UNT Libraries Government Documents Department
open access

The state-of-the-art port of entry workshop

Description: The increased demand for freight movements through international ports of entry and the signing of the North American Free Trade Agreement (NAFTA) have increased freight traffic at border ports of entry. The State-of-the-Art Port of Entry Workshop initiated a dialogue among technologists and stakeholders to explore the potential uses of technology at border crossings and to set development priorities. International ports of entry are both information and labor intensive, and there are many prom… more
Date: May 1, 1995
Creator: Godfrey, B.
Partner: UNT Libraries Government Documents Department
open access

Compact X-band high power load using magnetic stainless steel

Description: We present design and experimental results of a high power X-band load. The load is formed as a disk-loaded waveguide structure using lossy, Type 430 stainless steel. The design parameters have been optimized using the recently developed mode-matching code MLEGO. The load has been designed for compactness while maintaining a band width greater than 300 MHz.
Date: May 1, 1995
Creator: Tantawi, S. G. & Vlieks, A. E.
Partner: UNT Libraries Government Documents Department
open access

Development of a photovoltaic module energy ratings methodology

Description: The National Renewable Energy Laboratory has begun work on developing a consensus-based approach to rating photovoltaic modules. This new approach was intended to address the limitations of the defacto standard module power rating at standard test conditions. Using technical input from a number of sources, and under the guidance of an industry-based technical review committee, the approach described in this paper was developed. The Module Energy Rating (MER) consists of 10 estimates of how much… more
Date: May 1, 1995
Creator: Kroposki, B.; Mrig, L.; Whitaker, C. & Newmiller, J.
Partner: UNT Libraries Government Documents Department
open access

Interval neural networks

Description: Traditional neural networks like multi-layered perceptrons (MLP) use example patterns, i.e., pairs of real-valued observation vectors, ({rvec x},{rvec y}), to approximate function {cflx f}({rvec x}) = {rvec y}. To determine the parameters of the approximation, a special version of the gradient descent method called back-propagation is widely used. In many situations, observations of the input and output variables are not precise; instead, we usually have intervals of possible values. The imprec… more
Date: May 1, 1995
Creator: Patil, R. B.
Partner: UNT Libraries Government Documents Department
open access

Beam trajectory jitter in the SLC linac

Description: We present model-independent measurements of the vertical trajectory jitter of the positron beam in the Stanford Linear Collider (SLC) linac and discuss the results of studies aimed at isolating its source.
Date: May 1, 1995
Creator: Adolphsen, C. & Slaton, T.
Partner: UNT Libraries Government Documents Department
open access

Can T phases be used to map blockage?

Description: The placement of stations in a CTBT hydroacoustic monitoring network is controlled, in large part, by the presence of bathymetric features or land masses that block propagation. In the absence of blocking features, propagation is very efficient in the SOFAR channel, allowing surveillance over large basins with hydrophone networks that are sparse compared to seismic networks. Blockage can be estimated from theoretical calculations of acoustic attenuation. While calibration of attenuation with co… more
Date: May 1, 1995
Creator: Harris, D. & Hauk, T.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen