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Diffusion of Slow Electrons in Gases (open access)

Diffusion of Slow Electrons in Gases

The properties of electrons in a gas and an external electric field, e.g., agitation velocity, free path, energy lost per collision, and collision cross sections, were determined for electrons of energy less than 2 ev in a large number of gases. The computations were made from previously measured values for Townsend's energy factor or the ratio of electron agitation energy to molecule thermal energy. Results are presented for hydrogen, nitrogen, carbon dioxide, methane, ethylene, cyclopropane, and argon. (D.L.C.)
Date: October 24, 1961
Creator: Forester, D. W. & Cochran, L. W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Waste Treatment and Disposal Progress Report for June and July 1961 (open access)

Waste Treatment and Disposal Progress Report for June and July 1961

7 7 6 4 : 9 8 9 6 5 : 9 aluminum nitrate waste was calcined in the close-coupled continuous evaporator-pot calciner unit. Waste oxides from TBP-25 waste were incorporated into glassy materials after the addition of phosphate and borate fluxing agents. Melts formed at 850 to 950 deg C were glassy solids when cooled and had densities from 2.41 to 2.47 g/ml. Waste volurne reduction factors were from 7.6 to 9.3. Low-Level Waste Treatment. A demonstration run was completed in the 60 liters/hr scavenging-ion exchange pilot plant on ORNL low-activity waste. Decontamination factors were satisfactory after 1500 resin bed voluumes of waste had been treated, i. e, Sr> 1000, TRE 100, Cs> 100, and sufficiently high for other activities that the waste activity was reduced to <10% of MPC. The physical properties of vermiculite, clinoptilolite, and rock phosphate were found to be suitable for second-stage treatment of process waste. Engineering, Econommc, and Hazards Evaluation. A cost study of the conversion of high-level solutions to solids by pot calcimation was completed. Aging had a negligible effect on costs for processing in a given vessel size. The lowest cost was 0.87 x 10/sup-2/ mill/kwh/sub 3/ for processing acidic Purex and …
Date: October 24, 1961
Creator: Blanco, R. E. & Struxness, E. G.
Object Type: Report
System: The UNT Digital Library
Building 431 fire tests (open access)

Building 431 fire tests

An extensive discussion of considerations for fire protection in the LLL mirror fusion test facility (MFTF) is presented. Because of the large volume and high bays of the building, sufficient data on fire detection is unavailable. Results of fire detection tests using controlled fire sources in the building are presented. Extensive data concerning the behavior of the building atmosphere are included. Candidate fire detection instrumentation and extinguishing systems for use in the building are briefly reviewed. (RME)
Date: October 24, 1977
Creator: Alvares, N. J.; Beason, D. G.; Ford, H. W. & Magee, M. W.
Object Type: Report
System: The UNT Digital Library
Energy balance measurements for Shiva (open access)

Energy balance measurements for Shiva

The Lawrence Livermore Laboratory Shiva laser-target interaction facility is designed for experiments at 20 to 30 terawatts. At this power level there will be larger fluxes of neutrons, x-rays, electrons and ions than have been previously measured. The measurements of energy converted into the various reaction products is crucial both in target design and performance analysis of the actual experiment. The total energy absorbed is measured by a box calorimeter surrounding the target except for beam input holes. This measurement prevents the use of other diagnostics, so for normal operation an energy balance module was designed for location on ports on the Shiva target chamber. This module monitors the energy in scattered light at 10640 A and 5320 A or 7118 A. It also contains a faraday cup and plasma and x-ray calorimeters. The distribution of energy in scattered light, plasma and x-rays will be mapped by 58 such modules.
Date: October 24, 1977
Creator: Glaros, S.S.; Rupert, V.C.; Gunn, S.R.; Phillion, D.W. & Kornblum, H.N.
Object Type: Article
System: The UNT Digital Library
Periodic Intercalibration of Temperature Sensing Elements, Core I, Seed I. Test Results T-641306 (open access)

Periodic Intercalibration of Temperature Sensing Elements, Core I, Seed I. Test Results T-641306

BS>Intercalibration data for various temperature sensing elements in the reactor coolant system are obtained and compared with calculated source activity levels and observed channel levels. The readings of 20 of the 62 core thermocouples were either less than 400 deg F, which was off scale on the recorder, or were plus or minus 20 deg F from the calibrating resistance thermometer temperatures. The remainder of the readings were within plus or minus 3% of the temperatures of the calibrating thermometers which were used as a standard of comparison. The main coolant loop resistance thermometers all read within plus or minus 0.2% of the calibrating thermometers. The data from the nuclear source range instrumentation indicated a level ranging from less than 1.7 cps to 31 cps; Channel A indicating the highest. The recorded source activity levels were generally higher than the calculated source activity levels as they should be. There appeared to be no correlation between coolant temperature and source log level source range indications. (N.W.R.)
Date: October 24, 1960
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Establishment and maintenance of a coal sample bank and data base (open access)

Establishment and maintenance of a coal sample bank and data base

In the project status report for 4/9/90--7/8/90, Table 2 presented update results of a comparative study of coal sample deterioration in several container types including foil laminate bags. This table contained an erroneous entry (foil laminate bag {minus}20 mesh, alkali extraction 65.4% transmittance). The alkali extraction test on {minus}20 mesh coal stored in foil laminate bags for 52 weeks was repeated in duplicate on another bag (after 64 weeks total storage) resulting in a measurement of 96.2% transmittance. This value has been substituted for the erroneous 65.4% value in the corrected copy of Table 2 enclosed with this report. All values of the alkali extraction and Gieseler fluidity tests indicate that the state of preservation of sample in foil laminate bags is excellent. The samples stored by other methods for comparison purposes all showed significant loss in fluid characteristics. One new whole-seam channel sample of the hvAb Pittsburgh seam coal, DECS-12, was collected July 25, 1990 in Greene County, PA. This sample was placed in 30-gallon steel barrels with high-density lid gaskets and purged with argon at the mine. Upon return to Penn State it was promptly processed so that Gieseler fluidity and other routine analyses could be performed.
Date: October 24, 1990
Creator: Davis, A.
Object Type: Report
System: The UNT Digital Library
Shiva optical diagnostics (open access)

Shiva optical diagnostics

In the laser fusion program at Lawrence Livermore Laboratory, no target experiment is complete unless it is complemented by careful measurements of the laser pulse that irradiates the target. For this purpose, an incident beam diagnostics (IBD) package has been designed for the Shiva laser. The package will furnish data on items such as the total energy and the focusable energy out of the laser chain, and the spatial and temporal energy and power distribution at the target plane. Understanding laser-plasma interactions requires knowledge of the amount of 1.06 ..mu..m light energy that is scattered in various directions from the target. The light energy that is scattered toward the beam focusing lens is analyzed by a reflected beam diagnostic (RBD) package containing a calorimeter, a multiple image camera and a TV camera. This paper describes the detailed design and operation of the IBD and RBD packages as tools to align spatial filters and targets, as well as to diagnose the laser beams and target reflectivity.
Date: October 24, 1977
Creator: Rienecker, F.; Kobierecki, M.; Ozarski, R.; Seppala, L.; Manes, K. & Merritt, B.
Object Type: Article
System: The UNT Digital Library
Energy sensitivity and variability analysis of Populus hybrid short-rotation plantations in northeastern United States. Final report (open access)

Energy sensitivity and variability analysis of Populus hybrid short-rotation plantations in northeastern United States. Final report

Production of biomass by corn-like plantations has been demonstrated by a number of researchers. These forest analogs of agronomic cropping systems have the potential to yield substantially more biomass per unit area than traditional forests. Care is needed in choosing the appropriate sites, species, spacing, and harvesting strategies. Opportunities for increased yields have been suggested for fertilization and irrigation. Utilization of the biomass from these dense plantations for energy was the focus of this study. Although the amount of energy potential of the biomass is important, the energy output must be greater than the energy input for biomass to have a positive benefit to society. Further, in order to completely evaluate the net energy of the system it is necessary to examine the energy out-to-in ratios on the basis of usable energy (for example, usable heat, process steam and electricity), as well as all of the energies expended in producing, harvesting, transporting and processing the biomass. The objective of this study is to establish and analyze the energy inputs for selected management strategies in order to evaluate the sensitivity and variability of the energy inputs in the net energy analysis, and based on the net energy analysis to recommend a …
Date: October 24, 1979
Creator: Bowersox, T.W. & Blankenhorn, P.R.
Object Type: Report
System: The UNT Digital Library
Theory-based transport simulations of TFTR L-mode temperature profiles (open access)

Theory-based transport simulations of TFTR L-mode temperature profiles

The temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient ({eta}{sub i}) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the periphery. Within the context of this transport model and the TFTR simulations reported here, the scaling of confinement with heating power comes from the temperature dependence of the {eta}{sub i} and trapped electron modes, while the scaling with current comes mostly from resistive ballooning modes. 24 refs., 16 figs., 3 tabs.
Date: October 24, 1991
Creator: Bateman, G.
Object Type: Report
System: The UNT Digital Library
Pion induced double-charge exchange above the resonance (open access)

Pion induced double-charge exchange above the resonance

The zero degree excitation function for ({pi}{sup +}, {pi}{sup -}) is calculated for pion energies of 300 to 1400 MeV assuming a sequential mechanism. The cross section around 1225 MeV is 10{sup 4} smaller than at 800 MeV. Experiments at this energy should be ideal for searches for effects due to exchange currents, and other non-conventional mechanisms. 15 refs.
Date: October 24, 1989
Creator: Oset, E.; Strottman, D. (Valencia Univ. (Spain). Dept. de Fisica Teorica & Los Alamos National Lab., NM (USA))
Object Type: Article
System: The UNT Digital Library
Fallout model for system studies (open access)

Fallout model for system studies

A versatile fallout model was developed to assess complex civil defense and military effect issues. Large technical and scenario uncertainties require a fast, adaptable, time-dependent model to obtain technically defensible fallout results in complex demographic scenarios. The KDFOC2 capability, coupled with other data bases, provides the essential tools to consider tradeoffs between various plans and features in different nuclear scenarios and estimate the technical uncertainties in the predictions. All available data were used to validate the model. In many ways, the capability is unmatched in its ability to predict fallout hazards to a society.
Date: October 24, 1979
Creator: Harvey, T. F. & Serduke, F. J. D.
Object Type: Report
System: The UNT Digital Library
Analytical chemical system for the determination of heavy metals and organic compounds. Annual progress report, December 1, 1978-November 30, 1979 (open access)

Analytical chemical system for the determination of heavy metals and organic compounds. Annual progress report, December 1, 1978-November 30, 1979

Progress has been made in the synthesis and characterization of new resins for sequestering inorganic and organic compounds. The capabilities of the poly(dithiocarbamate) resin have been extended, a new poly(acrylamidoxime) resin prepared and characterized, and a series of resins for organic compounds prepared and tested. Limited actual sample analyses have been performed with these resins. A new inductively coupled plasma source, spectrometer, and computer system have been received and they are undergoing tests and installation. With this system in place, the multielement analysis of metals during the forthcoming period will insure the application of sequestering resins to practical analysis of energy-related materials. An automated sample handling and data system has been designed, some components purchased, and construction is scheduled for 1980.
Date: October 24, 1979
Creator: Siggia, S. & Barnes, R. M.
Object Type: Report
System: The UNT Digital Library
Analysis of dense pusher laser-driven implosions for intermediate densities (open access)

Analysis of dense pusher laser-driven implosions for intermediate densities

Post-shot analysis of targets designed to achieve a diagnosible compression of DT gas to 2. g/cm/sup 3/ or 10 x liquid density is reported. The SHIVA laser provided 15 to 20 TW of 1.06 ..mu..m laser light. Detailed comparisons of diagnostic results with hydro-code calculations are made. Implications for laser light absorption/scattering, thermal conduction, suprathermal electron preheat, implosion symmetry, and pusher-fuel mix are discussed. Uncertainties of the density determination methods are analyzed. Good overall consistency is found, indicating strong support for the successful attainment of 1.-3. g/cm/sup 3/.
Date: October 24, 1979
Creator: Mead, W. C.; Orth, C. D.; Bailey, D. S.; McClellan, G. & Estabrook, K. G.
Object Type: Article
System: The UNT Digital Library
Waste systems. Progress report, January 1982-February 1983 (open access)

Waste systems. Progress report, January 1982-February 1983

A laboratory-scale beryllium electrorefining cell has been placed in operation and metallic beryllium with a purity greater than 99.95% has been produced. Methods of uranium chip disposal have been evaluated by performing bench- and pilot-scale testing and by surveying present chip disposal methods. A design criteria has been completed for a new production uranium chip disposal facility. Two types of cementation immobilization processes are being developed to treat several Rocky Flats wastes which do not currently meet repository acceptance criteria. The nitrate salts, as now shipped, are an extremely fine powder, composed chiefly of sodium and potassium nitrate. Nitrates are an oxidizer, and their behavior in a possible fire would be of concern. Accident caused fires involving a cargo of boxed nitrate salts were modeled and the burning characteristics noted. In addition, gypsum cement was tested as an immobilization matrix to reduce dispersibility. A program is in process to construct a facility to remotely size reduce gloveboxes and miscellaneous equipment contaminated with plutonium and other radioactive nuclides. The Title II engineering package is completed and the construction of the facility has been initiated. Modification and additions to the 82 kg/h Fluidized Bed Incinerator were made in preparation for turning the …
Date: October 24, 1983
Creator: Hickle, G.L.
Object Type: Report
System: The UNT Digital Library
A RESONANCE IN THE Lambda pi SYSTEM (open access)

A RESONANCE IN THE Lambda pi SYSTEM

The authors report a study of the reaction K{sup -} + p {yields} {Lambda}{sup 0} + {pi}{sup +} + {pi}{sup -} produced by 1.15 Gev/c K{sup -} mesons and observed in the Lawrence Radiation Laboratory's 15-in. hydrogen bubble chamber. A preliminary report of these results was presented at the 1960 Rochester Conference. The beam was purified by two velocity spectrometers. A hyperon/observed during the run and the preliminary cross sections for various K{sup -} reactions at 1.15 Bev/c have been reported previously. Reaction (1) was the first one selected for detailed study, because it appeared to take place with relatively large probability and because the event, a 2-prong interaction accompanied by a V, was easily identified. In a volume of the chamber sufficiently restricted so that the scanning efficiency was near 100%, 255 such events were found. These events were measured, and the track data supplied to a computer which tested each event for goodness of fit to various kinematic hypotheses. The possible reactions, the distribution of events, and the corresponding cross sections are given in Table I. An event was placed in a given category of Table I if the {chi}{sup 2} probability for the other hypotheses was < …
Date: October 24, 1960
Creator: Alston, Margaret; Alvarez, Luis W.; Eberhard, Philippe & Wojcicki, Stanley G.
Object Type: Report
System: The UNT Digital Library
Quantifying the Diffusion of a Fluid through Membranes by RemoteDetection MRI (open access)

Quantifying the Diffusion of a Fluid through Membranes by RemoteDetection MRI

We present a method to measure self-diffusion acrossmembranes without the need for concentration or pressure gradients.Hyperpolarized xenon in combination with remote detection of NMR allowsthe measurement of membrane permeation, even in the gas phase. Theresulting images allow quantification of the amount of fluid diffusedthrough the membrane, and represent an alternative, potentially moreprecise way of measuring a membrane diffusion coefficient. The use ofremote detection of NMR allows for non-invasive signal encoding coupledto sensitive detection, making this approach ideal for the study ofdiffusion in intact devices such as fuel cells or separationsystems.
Date: October 24, 2006
Creator: Telkki, Ville-Veikko; Hilty, Christian; Garcia, Sandra; Harel,Elad & Pines, Alexander
Object Type: Article
System: The UNT Digital Library
Where Water is Oxidized to Dioxygen: Structure of the Photosynthetic Mn4Ca Cluster from X-ray Spectroscopy (open access)

Where Water is Oxidized to Dioxygen: Structure of the Photosynthetic Mn4Ca Cluster from X-ray Spectroscopy

Light-driven oxidation of water to dioxygen in plants, algae and cyanobacteria iscatalyzed within photosystem II (PS II) by a Mn4Ca cluster. Although the cluster has been studied by many different methods, the structure and the mechanism have remained elusive. X-ray absorption and emission spectroscopy and EXAFS studies have been particularly useful in probing the electronic and geometric structure, and the mechanism of the water oxidation reaction. Recent progress, reviewed here, includes polarized X-ray absorption spectroscopy measurements of PS II single crystals. Analysis of those results has constrained the Mn4Ca cluster geometry to a setof three similar high-resolution structures. The structure of the cluster from the present study is unlike either the 3.0 or 3.5 Angstrom-resolution X-ray structures or other previously proposed models. The differences between the models derived from X-rayspectroscopy and crystallography are predominantly because of damage to the Mn4Ca cluster by X-rays under the conditions used for structure determination by X-ray crystallography. X-ray spectroscopy studies are also used for studying the changes in the structure of the Mn4Ca catalytic center as it cycles through the five intermediate states known as the Si-states (i=0-4). The electronic structure of the Mn4Ca cluster has been studied more recently using resonant inelastic X-ray …
Date: October 24, 2007
Creator: Yano, Junko; Yano, Junko & Yachandra, Vittal K.
Object Type: Article
System: The UNT Digital Library
Passive Detection of Narrowband Sources Using a Sensor Array (open access)

Passive Detection of Narrowband Sources Using a Sensor Array

In this report we derive a model for a highly scattering medium, implemented as a set of MATLAB functions. This model is used to analyze an approach for using time-reversal to enhance the detection of a single frequency source in a highly scattering medium. The basic approach is to apply the singular value decomposition to the multistatic response matrix for a time-reversal array system. We then use the array in a purely passive mode, measuring the response to the presence of a source. The measured response is projected onto the singular vectors, creating a time-reversal pseudo-spectrum. We can then apply standard detection techniques to the pseudo-spectrum to determine the presence of a source. If the source is close to a particular scatterer in the medium, then we would expect an enhancement of the inner product between the array response to the source with the singular vector associated with that scatterer. In this note we begin by deriving the Foldy-Lax model of a highly scattering medium, calculate both the field emitted by the source and the multistatic response matrix of a time-reversal array system in the medium, then describe the initial analysis approach.
Date: October 24, 2007
Creator: Chambers, D H; Candy, J V & Guidry, B L
Object Type: Report
System: The UNT Digital Library
Research project on CO2 geological storage and groundwaterresources: Large-scale hydrological evaluation and modeling of impact ongroundwater systems (open access)

Research project on CO2 geological storage and groundwaterresources: Large-scale hydrological evaluation and modeling of impact ongroundwater systems

If carbon dioxide capture and storage (CCS) technologies areimplemented on a large scale, the amounts of CO2 injected and sequesteredunderground could be extremely large. The stored CO2 then replaces largevolumes of native brine, which can cause considerable pressureperturbation and brine migration in the deep saline formations. Ifhydraulically communicating, either directly via updipping formations orthrough interlayer pathways such as faults or imperfect seals, theseperturbations may impact shallow groundwater or even surface waterresources used for domestic or commercial water supply. Possibleenvironmental concerns include changes in pressure and water table,changes in discharge and recharge zones, as well as changes in waterquality. In compartmentalized formations, issues related to large-scalepressure buildup and brine displacement may also cause storage capacityproblems, because significant pressure buildup can be produced. Toaddress these issues, a three-year research project was initiated inOctober 2006, the first part of which is summarized in this annualreport.
Date: October 24, 2007
Creator: Birkholzer, Jens; Zhou, Quanlin; Rutqvist, Jonny; Jordan, Preston; Zhang, K. & Tsang, Chin-Fu
Object Type: Report
System: The UNT Digital Library
Does complex absorption behavior leading to conditioning and damage in KDP/DKDP reflect the electronic structure of initiators? (open access)

Does complex absorption behavior leading to conditioning and damage in KDP/DKDP reflect the electronic structure of initiators?

Currently, most of our thinking about the defects responsible for initiating laser damage considers them as featureless absorbers. However, an increasing body of evidence, particularly involving multi-wavelength irradiation, suggests electronic structure of damage initiators is important in determining both initiation and conditioning behaviors in KDP. The effective absorption coefficient of energy under multi-wavelength irradiation cannot be accounted for by a structureless absorber, but is consistent with an initiator with a multi-level structure. We outline the evidence and assess the ability of such a simple multi-level model to explain these and other experimentally observed behaviors.
Date: October 24, 2007
Creator: Feit, M D; DeMange, P P; Negres, R A; Rubenchik, A M & Demos, S G
Object Type: Article
System: The UNT Digital Library
Experimental and Numerical Investigation of Flows in Expanding Channels (open access)

Experimental and Numerical Investigation of Flows in Expanding Channels

We present an experimental realization of the classical Jeffery-Hamel flows inside a wedge-shaped channel. We compare the measured velocity fields with the predictions of Jeffery-Hamel theory. A detailed experimental study of bifurcation diagrams for the solutions reveals the absolute stability of the pure outflow solution and an interesting hysteretic structure for bifurcations. We also observe a multiple vortex flow regime predicted earlier numerically and analytically. Experimental studies of the stability of the flow to perturbations at the channel exit are also conducted.
Date: October 24, 2008
Creator: Vorobieff, Peter & Putkaradze, Vakhtang
Object Type: Report
System: The UNT Digital Library
Science & Technology Review December 2007 (open access)

Science & Technology Review December 2007

This month's issue has the following articles: (1) Homeland Security Begins Abroad--Commentary by John C. Doesburg; (2) Out of Harm's Way--New physical protection and accountability systems, together with a focus on security, safeguard nuclear materials in the Russian Federation; (3) A Calculated Journey to the Center of the Earth--Determining the permeability of partially melted metals in a mineral matrix unlocks secrets about the formation of Earth's core; (4) Wireless That Works--Communication technologies using ultrawideband radar are improving national security; and (5) Power to the People--Edward Teller envisioned safe and plentiful nuclear power for peaceful applications.
Date: October 24, 2007
Creator: Chinn, D. J.
Object Type: Report
System: The UNT Digital Library
Femtosecond Time-Delay X-Ray Holography (open access)

Femtosecond Time-Delay X-Ray Holography

X-ray free-electron lasers (XFELs) will produce photon pulses with a unique and desirable combination of properties. Their short X-ray wavelengths allow penetration into materials and the ability to probe structure at and below the nanometer scale. Their ultra-short duration gives information about this structure at the fundamental time-scales of atoms and molecules. The extreme intensity of the pulses will allow this information to be acquired in a single shot, so that these studies can be carried out on non-repeatable processes or on weakly-scattering objects that will be modified by the pulse. A fourth property of XFEL pulses is their high transverse coherence, which brings the promise of decades of innovation in visible optics to the X-ray regime, such as holography, interferometry, and laser-based imaging. Making an effective use of XFEL pulses, however, will benefit from innovations that are new to both X-ray science and coherent optics. One such innovation is the new method of time-delay X-ray holography [1], recently demonstrated at the FLASH FEL at DESY in Hamburg, to measure the evolution of objects irradiated by intense pulses. One of the pressing questions about the high-resolution XFEL imaging and characterization of non-periodic or weakly-scattering objects is the effect of the …
Date: October 24, 2007
Creator: Chapman, H N
Object Type: Report
System: The UNT Digital Library
Scalable High Performance Message Passing over InfiniBand for Open MPI (open access)

Scalable High Performance Message Passing over InfiniBand for Open MPI

InfiniBand (IB) is a popular network technology for modern high-performance computing systems. MPI implementations traditionally support IB using a reliable, connection-oriented (RC) transport. However, per-process resource usage that grows linearly with the number of processes, makes this approach prohibitive for large-scale systems. IB provides an alternative in the form of a connectionless unreliable datagram transport (UD), which allows for near-constant resource usage and initialization overhead as the process count increases. This paper describes a UD-based implementation for IB in Open MPI as a scalable alternative to existing RC-based schemes. We use the software reliability capabilities of Open MPI to provide the guaranteed delivery semantics required by MPI. Results show that UD not only requires fewer resources at scale, but also allows for shorter MPI startup times. A connectionless model also improves performance for applications that tend to send small messages to many different processes.
Date: October 24, 2007
Creator: Friedley, A.; Hoefler, T.; Leininger, M. L. & Lumsdaine, A.
Object Type: Article
System: The UNT Digital Library