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

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

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 {+-} 20 ng per cigarette for N-nitrosodimethylamine and N-nitrosopyrrolidine, respectively. The emission factors were used to estimate VNA exposures from ETS in a typical office building and an average residence. Indoor concentrations of N,N dimethylnitrosamine from ETS for these scenarios were less than 10% of the reported median outdoor concentration. This median outdoor concentration, however, includes many measurements made in source-dominated areas and may be considerably higher than one based on more representative sampling of outdoor air.
Date: May 1, 1995
Creator: Mahanama, K. R. R. & Daisey, J. M.
System: The UNT Digital Library
A computational method for comparing the behavior and possible failure of prosthetic implants (open access)

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

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 be applied to any other human joints for which prosthetic implants have been designed. Preliminary results of prosthetic joint loading, without surrounding human tissue (i.e., simulating conditions under which the prosthetic joint has not yet been implanted into the human joint), are presented, based on a three-dimensional, nonlinear finite element analysis of three different joint implant designs.
Date: May 1, 1995
Creator: Nielsen, C.; Hollerbach, K.; Perfect, S. & Underhill, K.
System: The UNT Digital Library
Methodological issues in the validation of complex human-machine systems (open access)

Methodological issues in the validation of complex human-machine systems

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 validation tests to predicted performance of the integrated system emerges from the comparability of the psychological and physical processes of the test and actual situations. Generalizability of results is supported when the integrated system, operating conditions and performance are representative of their real-world counterparts. The methodological considerations for establishing representativeness are discussed.
Date: May 1, 1995
Creator: O`Hara, J.; Stubler, W. & Wachtel, J.
System: The UNT Digital Library
PEP-III magnet power conversion systems: Power supplies for large magnet strings (open access)

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

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 facilities while at the same time satisfying tight constraints for cost control, scheduling and coordination of different working groups. Switch-mode power conversion techniques will be used extensively in these systems, from the corrector supplies to the largest units if the dynamic performance specifications demand it. General system descriptions for each of the power supply ranges and for a new common control system interface and regulator are included.
Date: May 1, 1995
Creator: Jackson, T.; Saab, A. & Shimer, D.
System: The UNT Digital Library
Biochemical technology for the detoxification of geothermal brines and the recovery of trace metals (open access)

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

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 applications beyond that of rendering hazardous and/or mixed wastes to non-hazardous by products, which meet regulatory requirements. This technology may be used for solubilization or recovery of a few metals to the isolation of many metals including radionuclides. In the metal recovery mode, an aqueous phase is generated which meets regulatory standards. The resulting concentrate contains valuable trace metals and salts which can be further converted into income generating products which can off-set the initial investment costs associated with the new biotechnology. In this paper, recent developments in this emerging technology will be discussed.
Date: May 1, 1995
Creator: Premuzic, E.T.; Lin, M.S. & Lian, Hsienjen
System: The UNT Digital Library
Determination of modal residues and residual flexibility for time-domain system realization (open access)

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

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 identification. Primary among these are the ability to identify data sets with large numbers of sensors using small numbers of reference point responses, and the inclusion of terms which accurately model the effects of residual flexibility. The accuracy and efficiency of the present realization theory-based procedure is demonstrated for both simulated and experimental data.
Date: May 1, 1995
Creator: Alvin, K. F. & Peterson, L. D.
System: The UNT Digital Library
Computer modeling of electrical performance of detonators (open access)

Computer modeling of electrical performance of detonators

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 paper entitled ``Cable Discharge System for Fundamental Detonator Studies`` presented at the 2nd NASA/DOD/DOE Pyrotechnic Workshop.
Date: May 1, 1995
Creator: Furnberg, C.M.; Peevy, G.R.; Brigham, W.P. & Lyons, G.R.
System: The UNT Digital Library
Hydrogen program combustion research: Three dimensional computational modeling (open access)

Hydrogen program combustion research: Three dimensional computational modeling

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 development at Sandia National Laboratory. Overall the valve model is shown to have comparable accuracy as the general flow simulation capability in KIVA-3, which has been well validated by past comparisons to experiments. In the exploratory simulations of the Onan engine, the standard use of the single kinetic reaction for hydrogen oxidation was found to be inadequate for modeling the hydrogen combustion because of its inability to describe both the observed laminar flame speed and the absence of autoignition in the Onan engine. We propose a temporary solution that inhibits the autoignition without sacrificing the ability to model spark ignition. In the absence of experimental data on the Onan engine, a computational investigation was undertaken to evaluate the importance of modeling the intake flow on the combustion …
Date: May 1, 1995
Creator: Johnson, N. L.; Amsden, A. A. & Butler, T. D.
System: The UNT Digital Library
Quench antennas for RHIC quadrupole magnets (open access)

Quench antennas for RHIC quadrupole magnets

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. Several antennas have been developed for RHIC magnets and they are now routinely used for quench tests of production magnets. The paper discusses the description of the method and introduces a measured example using an antenna designed for quadrupole magnets.
Date: May 1, 1995
Creator: Ogitsu, T.; Terashima, A.; Tsuchiya, K.; Ganetis, G.; Muratore, J. & Wanderer, P.
System: The UNT Digital Library
Flat panel planar optic display. Revision 4/95 (open access)

Flat panel planar optic display. Revision 4/95

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.
System: The UNT Digital Library
Alignment and survey of the elements in RHIC (open access)

Alignment and survey of the elements in RHIC

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 shape within a colloidal cell placed inside the quadrupoles. Special attention is given to the triplet quadrupole alignment and determination of the field center position.
Date: May 1, 1995
Creator: Trbojevic, D.; Cameron, P. & Ganetis, G. L.
System: The UNT Digital Library
A diethyl phosphonate containing oxazoline: Synthesis and characterization of monomer and homopolymer (open access)

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

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.
System: The UNT Digital Library
Recent progress on beam stability study in the PSR (open access)

Recent progress on beam stability study in the PSR

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 studies indicate that the instability in the PSR is most likely driven by electrons trapped within the proton beam. Recent studies using an experimental electron-clearing system and voltage-biased pinger-electrodes for electron clearing and collection support this hypothesis. Experiments have also been performed to study the instability threshold when varying the electron production rate. Theoretical studies include a computer simulation of a simplified model for the e -- p instability and the investigation of possible electron confinement in the ring-element magnetic fields. This paper reports some recent results from these studies.
Date: May 1, 1995
Creator: Wang, T.; Channell, P. & Cooper, R.
System: The UNT Digital Library
The state-of-the-art port of entry workshop (open access)

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

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 promising technologies that could be used to provide timely information and optimize inspection resources. Participants universally held that integration of technologies and operations is critical to improving port services. A series of Next Steps was developed to address stakeholder issues and national priorities, such as the National Transportation Policy and National Drug Policy. This report documents the views of the various stakeholders and technologists present at the workshop and outlines future directions of study.
Date: May 1, 1995
Creator: Godfrey, B.
System: The UNT Digital Library
Compact X-band high power load using magnetic stainless steel (open access)

Compact X-band high power load using magnetic stainless steel

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.
System: The UNT Digital Library
Development of a photovoltaic module energy ratings methodology (open access)

Development of a photovoltaic module energy ratings methodology

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 energy a single typical module of a particular type will produce in one day, one for each of 5 different weather/location combinations and 2 load-types. This paper presents an overview of the procedures required to generate an MER for any particular module type.
Date: May 1, 1995
Creator: Kroposki, B.; Mrig, L.; Whitaker, C. & Newmiller, J.
System: The UNT Digital Library
Interval neural networks (open access)

Interval neural networks

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 imprecision could be due to the limited accuracy of the measuring instrument or could reflect genuine uncertainty in the observed variables. In such situation input and output data consist of mixed data types; intervals and precise numbers. Function approximation in interval domains is considered in this paper. We discuss a modification of the classical backpropagation learning algorithm to interval domains. Results are presented with simple examples demonstrating few properties of nonlinear interval mapping as noise resistance and finding set of solutions to the function approximation problem.
Date: May 1, 1995
Creator: Patil, R. B.
System: The UNT Digital Library
Beam trajectory jitter in the SLC linac (open access)

Beam trajectory jitter in the SLC linac

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.
System: The UNT Digital Library
Can T phases be used to map blockage? (open access)

Can T phases be used to map blockage?

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 controlled sources is best, it is also prohibitively expensive. The T phases generated by undersea earthquakes are known to be sensitive to interruptions of the SOFAR channel. Earthquakes along ridges may illuminate regions of interest to define blockage areas. Our initial examination of T phase amplitudes suggests that T phases can be used to map blockage or other strong path attenuation. The principal difficulty to be surmounted is the ambiguity between source coupling and path attenuation. We are attempting to quantify coupling with a probabilistic model, which would permit us to estimate attenuation and to quantify the reliability of the estimate.
Date: May 1, 1995
Creator: Harris, D. & Hauk, T.
System: The UNT Digital Library
Educational understanding of pollution prevention in decontamination and decommissioning/environmental restoration activities (open access)

Educational understanding of pollution prevention in decontamination and decommissioning/environmental restoration activities

Demolishing outdated structures from the US Department of Energy Hanford Site in Washington, generates large quantities of waste which can be minimized. The Hanford cleanup is one of the world`s largest and most complex environmental restoration efforts. Approximately 280 square miles of ground water and soil are contaminated; there are more than 80 surplus facilities, including nine shut-down nuclear reactors in various stages of decay; and there are 177 underground waste storage tanks containing highly radioactive waste. In all, 1,500 cleanup sites have been identified and the Environmental Restoration Contractor (ERC) is currently responsible for surveillance and maintenance of 170 structures. A two hour orientation training in pollution prevention was developed by the Westinghouse Hanford Company to provide all Decontamination and Decommissioning/Environmental Restoration (D&D/ER) personnel with the knowledge to apply waste minimization principles during their cleanup activities. The ERC Team Pollution Prevention Workshop serves to communicate pollution prevention philosophies and influences the way D&D/ER projects are conducted at the Hanford Site.
Date: May 1, 1995
Creator: Betsch, M. D. & Lewis, R. A.
System: The UNT Digital Library
Particulation in jets from free-form hemispherical shaped charges with copper liners (open access)

Particulation in jets from free-form hemispherical shaped charges with copper liners

Particulation in free-form hemispherical shaped charge jets is considerably different from that in conical shaped charge jets. From the analysis of the particulation data for 23 experiments covering ten free-form hemi designs with copper liners, it is concluded that jets with higher convergence pressures have delayed particulation, sometimes by as much as a factor of two. Breakup is also found to be design dependent, with free-form hemis have delayed breakup compared with cones. Also, in going from the earlier, boat-tail high explosive (HE) designs to later, more efficient hemispherical HE designs, it is found that particulation is delayed in the tail of the jet. These effects indicate the potential for deeper armor penetration based on control of particulation.
Date: May 1, 1995
Creator: Simonson, S. C., III; Haselman, L. C., Jr. & Breithaupt, R. D.
System: The UNT Digital Library
Characterization of three dimensional fiber orientation in short-fiber composites (open access)

Characterization of three dimensional fiber orientation in short-fiber composites

A mathematical procedure for recovering from image analysis the three dimensional nonsymmetric fiber-orientation distribution in short-fiber composites is proposed. Microphotographs from two orthogonal faces of a composite sample are needed to determine the three dimensional fiber orientation. A simple weighting function is derived to take into account the probability of intercepting fibers at varying inclination angles. The present procedure improves the previous works of other researchers in the following two aspects. First, it can obtain the single-angle fiber-orientation distribution from one micrograph in reference to the normal of the photographed surface. This distribution is often needed in predicting the mechanical and physical properties of short-fiber composites in this direction. Second, no symmetry in fiber-orientation distribution is assumed in the determination of the three dimensional fiber-orientation, which makes the present procedure more practical and versatile.
Date: May 1, 1995
Creator: Zhu, Yuntian T. & Blumenthal, W.R.
System: The UNT Digital Library
Modeling the segregation of hydrogen to lattice defects in nickel (open access)

Modeling the segregation of hydrogen to lattice defects in nickel

In order to better understand the effect of hydrogen on the fracture behavior of nickel, this study uses the embedded atom method (EAM) to model the segregation of hydrogen to lattice defects in nickel. The dislocations modeled include an edge, a screw, and a Lomer dislocation in the locked configuration, i.e. the Lomer-Cottrell Cock (LCL). Several coincident site lattice boundaries are also investigated, these being the {Sigma}3(112) and {Sigma}11(113) tilt boundaries. It will be shown that the trap site energies in the vicinity of both the edge and screw dislocations is only about 0.1 eV while for the LCL and all of the grain boundaries the maximum trap site energy in the vicinity of the defect is on order 0.3 eV. Using a Monte-Carlo method to a impose a hydrogen environment produces much stronger segregation of hydrogen to the deeper traps. When compared to recent experimental studies showing that a binding energy between 0.3-0.4 eV is required for trap site controlled fracture in IN903, it can be concluded that the embrittlement process is most probably associated with trapping of hydrogen to the Lomer-Cottrell Locks.
Date: May 1, 1995
Creator: Angelo, J.E.; Moody, N.R. & Baskes, M.I.
System: The UNT Digital Library
Feasibility study of a 1-MW pulsed spallation source (open access)

Feasibility study of a 1-MW pulsed spallation source

A feasibility study of a I-MW pulsed spallation source based on a rapidly cycling proton synchrotron (RCS) has been completed. The facility consists of a 400-MeV H{sup {minus}} linac, a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV, and two neutron-generating target stations. The design time-averaged current of the accelerator system is 0.5 mA, and is equivalent to 1.04 {times} 10{sup 14} protons per pulse. The linac system consists of an H{sup {minus}} ion source, a 2-MeV RFQ, a 70-MeV DTL and a 330-MeV CCL. Transverse phase space painting to achieve a Kapchinskij-Vladimirskij (K-V) distribution of the injected particles is accomplished by the charge exchange injection and programming of the closed orbit during the injection. The synchrotron lattice uses FODO cells of 9{degrees} phase advance. Dispersion-free straight sections are obtained by using a missing magnet scheme. Synchrotron magnets are powered by a dual-frequency resonance circuit that excites the magnets at a 20-Hz rate and de-excites them at a 60-Hz rate, resulting an effective rate of 30 Hz, and reducing the required rf power by 1/3. Details of the study are presented.
Date: May 1, 1995
Creator: Cho, Y.; Chae, Y.C. & Crosbie, E.
System: The UNT Digital Library