Cause of pitting in beryllium (open access)

Cause of pitting in beryllium

Light microscopy, bare-film radiography, secondary ion mass spectroscopy, electron microprobe and physical testing were used to examine beryllium specimens exhibiting a stratified, pitted, pattern after chemical milling. The objective was to find the cause of this pattern. Specimens were found to have voids in excess of density specification allowances. These voids are attributed, at least in part, to the sublimation of beryllium fluoride during the vacuum hot pressing operation. The origin of the pattern is attributed to these voids and etching out of fines and associated impurities. Hot isostatic pressing with a subsequent heat treatment close residual porosity and dispersed impurities enough to correct the problem.
Date: April 16, 1982
Creator: Kershaw, R. P.
Object Type: Article
System: The UNT Digital Library
Enhancing the use of coals by gas reburning-sorbent injection (open access)

Enhancing the use of coals by gas reburning-sorbent injection

The objective of this project is to evaluate and demonstrate a cost effective emission control technology for acid rain precursors, oxides of nitrogen (NO{sub x}) and sulfur (SO{sub x}), on two coal fired utility boilers in Illinois. The units selected are representative of pre-NSPS design practices: tangential and cyclone fired. A third unit, wall fired, is on hold'' because of funding limitations. The specific objectives are to demonstrate reductions of 60 percent in NO{sub x} and 50 percent in SO{sub x} emissions, by a combination of two developed technologies, gas reburning (GR) and sorbent injection (SI). With GR, about 80--85 percent of the coal fuel is fired in the primary combustion zone. The balance of this fuel is added downstream as natural gas to create a slightly fuel rich environment in which NO{sub x} is converted to N{sub 2}. The combustion process is completed by overfire air addition. SO{sub x} emissions are reduced by injecting dry sorbents (usually calcium based) into the upper furnace. The sorbents trap SO{sub x} as solid sulfates that are collected in the particulate control device.
Date: April 16, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
New concept for a high-power beam dump (open access)

New concept for a high-power beam dump

A new concept for a dump for the ion and neutral beams used in the controlled nuclear fusion program uses thin sheets of a refractory metal such as tungsten formed into troughs having semi-circular cross sections. High-velocity water flowing circumferentially removes heat by subcooled nucleate boiling. Possible advantages are modular construction, lower water-pumping power, and a lower pressure drop than in conventional beam dumps. An example design calculation is shown for a dump capable of absorbing an incident flux of 10 kW/cm/sup 2/.
Date: April 16, 1980
Creator: Moir, R.W. & Taylor, C.E.
Object Type: Article
System: The UNT Digital Library
Enhanced coal hydrogasification via oxidative pretreatment (open access)

Enhanced coal hydrogasification via oxidative pretreatment

The gasification of coal char by hydrogen is much slower than in steam or carbon dioxide; moreover, hydrogasification rate in pure hydrogen decreases sharply with conversion for most carbons. To overcome this kinetic behavior, the oxidation of the char prior to and during hydrogasification has been investigated as a means of enhancing hydro gasification rate. Kinetic rate studies under well-characterized conditions have been complemented by careful surface analyses to characterize oxygen on the char surface prior to and during hydrogasification.
Date: April 16, 1992
Creator: Miller, D.J.
Object Type: Report
System: The UNT Digital Library
Management of solid waste (open access)

Management of solid waste

Compliance with the latest regulatory requirements addressing disposal of radioactive, hazardous, and sanitary solid waste requires the application of numerous qualitative and quantitative criteria in the selection, design, and operation of solid waste management facilities. Due to the state of flux of these regulatory requirements from EPA and NRC, several waste management options were identified as being applicable to the management of the various types of solid waste. This paper highlights the current regulatory constraints and the design and operational requirements for construction of both storage and disposal facilities for use in management of DOE-ORO solid waste. Capital and operational costs are included for both disposal and storage options.
Date: April 16, 1980
Creator: Thompson, W.T. & Stinton, L.H.
Object Type: Article
System: The UNT Digital Library
Nuclear reactor control apparatus. [FBR] (open access)

Nuclear reactor control apparatus. [FBR]

Nuclear reactor safety rod release apparatus comprises a ring which carries detents normally positioned in an annular recess in outer side of the rod, the ring being held against the lower end of a drive shaft by magnetic force exerted by a solenoid carried by the drive shaft. When the solenoid is de-energized, the detent-carrying ring drops until the detents contact a cam surface associated with the lower end of the drive shaft, at which point the detents are cammed out of the recess in the safety rod to release the rod from the drive shaft. In preferred embodiments of the invention, an additional latch is provided to release a lower portion of a safety rod under conditions that may interfere with movement of the entire rod.
Date: April 16, 1981
Creator: Sridhar, B.N.
Object Type: Patent
System: The UNT Digital Library
H-coal fluid dynamics. Final report, August 1, 1977-December 31, 1979 (open access)

H-coal fluid dynamics. Final report, August 1, 1977-December 31, 1979

This report presents the results of work aimed at understanding the hydrodynamic behavior of the H-Coal reactor. A summary of the literature search related to the fluid dynamic behavior of gas/liquid/solid systems has been presented. Design details of a cold flow unit were discussed. The process design of this cold flow model followed practices established by HRI in their process development unit. The cold fow unit has been used to conduct experiments with nitrogen, kerosene, or kerosene/coal char slurries, and HDS catalyst, which at room temperature have properties similar to those existing in the H-Coal reactor. Mineral oil, a high-viscosity liquid, was also used. The volume fractions occupied by gas/liquid slurries and catalyst particles were determined by several experimental techniques. The use of a mini-computer for data collection and calculation has greatly accelerated the analysis and reporting of data. Data on nitrogen/kerosene/HDS catalyst and coal char fines are presented in this paper. Correlations identified in the literature search were utilized to analyze the data. From this analysis it became evident that the Richardson-Zaki correlation describes the effect of slurry flow rate on catalyst expansion. Three-phase fluidization data were analyzed with two models.
Date: April 16, 1980
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Solar heating system for the First Baptist Church, 1500 E. Melgaard Road, Aberdeen, South Dakota 57401. Final report (open access)

Solar heating system for the First Baptist Church, 1500 E. Melgaard Road, Aberdeen, South Dakota 57401. Final report

This report includes the following: (1) acceptance test plan, (2) systems performance data, (3) pictures of completed system, (4) problems in building the system, (5) description of the system, (6) major maintenance problems, (7) revised blueprints, (8) installation, operation, and maintenance manuals, and (9) recommendations.(MOW)
Date: April 16, 1979
Creator: Salem, H.E.
Object Type: Report
System: The UNT Digital Library
LOWER BOUNDS ON SELF-FOCUSING SO AS TO MAINTAIN RING INTEGRITY NEAR THE INITIATION OF ACCELERATION IN AN ELECTRON RING ACCELERATOR (open access)

LOWER BOUNDS ON SELF-FOCUSING SO AS TO MAINTAIN RING INTEGRITY NEAR THE INITIATION OF ACCELERATION IN AN ELECTRON RING ACCELERATOR

Relationships necessary for ring stability are derived between the self-focusing forces of an electron ring and the magnetic field gradient defocusing forces present near and just subsequent to the start of ring acceleration.
Date: April 16, 1970
Creator: Pellegrini, Claudio & Sessler, Andrew.
Object Type: Article
System: The UNT Digital Library
Strings on AdS2 and the high-energy limit of noncritical M-theory (open access)

Strings on AdS2 and the high-energy limit of noncritical M-theory

Abstract. Noncritical M-theory in 2+1 dimensions has been defined as a double-scaling limit of a nonrelativistic Fermi liquid on a flat two-dimensional plane. Here we study this noncritical M-theory in the limit of high energies, analogous to the alpha' --> infinity limit of string theory. In the related case of two-dimensional Type 0A strings, it has been argued that the conformal alpha' --> infinity limit leads to AdS_2 with a propagating fermion whose mass is set by the value of the RR flux. Here we provide evidence that in the high-energy limit, the natural ground state of noncritical M-theory similarly describes the AdS_2 x S1 spacetime, with a massless propagating fermion. We argue that the spacetime effective theory in this background is captured by a topological higher-spin extension of conformal Chern-Simons gravity in 2+1 dimensions, consistently coupled to a massless Dirac field. Intriguingly, the two-dimensional plane populated by the original nonrelativistic fermions is essentially the twistor space associated with the symmetry group of the AdS_2 x S1 spacetime; thus, at least in the high-energy limit, noncritical M-theory can be nonperturbatively described as a"Fermi liquid on twistor space.''
Date: April 16, 2007
Creator: Horava, Petr; Horava, Petr & Keeler, Cynthia A.
Object Type: Article
System: The UNT Digital Library
The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces (open access)

The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces

Over the past decade there has been a natural drive to extend the investigation of dynamic surfaces in fluid environments to higher resolution characterization tools. Various aspects of solution crystal growth have been directly visualized for the first time. These include island nucleation and growth using transmission electron microscopy and scanning tunneling microscopy; elemental step motion using scanning probe microscopy; and the time evolution of interfacial atomic structure using various diffraction techniques. In this lecture we will discuss the use of one such in situ method, scanning probe microscopy, as a means of measuring surface dynamics during crystal growth and dissolution. We will cover both practical aspects of imaging such as environmental control, fluid flow, and electrochemical manipulation, as well as the types of physical measurements that can be made. Measurements such as step motion, critical lengths, nucleation density, and step fluctuations, will be put in context of the information they provide about mechanistic processes at surfaces using examples from metal and mineral crystal growth.
Date: April 16, 2007
Creator: Orme, C. A. & Giocondi, J. L.
Object Type: Book
System: The UNT Digital Library
Meteorological Monitoring Program, Particulate Matter Ambient Air Quality Monitoring Report, January Through December 1996 (open access)

Meteorological Monitoring Program, Particulate Matter Ambient Air Quality Monitoring Report, January Through December 1996

None
Date: April 16, 1997
Creator: TRW Environmental Safety Systems, Inc.
Object Type: Report
System: The UNT Digital Library
EVALUATION OF RADIONUCLIDE ACCUMULATION IN SOIL DUE TO LONG-TERM IRRIGATION (open access)

EVALUATION OF RADIONUCLIDE ACCUMULATION IN SOIL DUE TO LONG-TERM IRRIGATION

Radionuclide accumulation in soil due to long-term irrigation is an important part of the model for predicting radiation dose in a long period of time. The model usually assumes an equilibrium condition in soil with a constant irrigation rate, so that radionuclide concentration in soil does not change with time and can be analytically solved. This method is currently being used for the dose assessment in the Yucca Mountain project, which requires evaluating radiation dose for a period of 10,000 years. There are several issues associated with the method: (1) time required for the equilibrium condition, (2) validity of constant irrigation rate, (3) agricultural land use for a long period of time, and (4) variation of a radionuclide concentration in water. These issues are evaluated using a numerical method with a simple model built in the GoldSim software. Some key radionuclides, Tc-99, Np-237, Pu-239, and Am-241 are selected as representative radionuclides. The results indicate that the equilibrium model is acceptable except for a radionuclide that requires long time to accumulate in soil and that its concentration in water changes dramatically with time (i.e. a sharp peak). Then the calculated dose for that radionuclide could be overestimated using the current equilibrium …
Date: April 16, 2006
Creator: Wu, De Wesley
Object Type: Article
System: The UNT Digital Library
Measurement of the Branching Fractions of the Rare Decays B0 to Ds(*)+pi-,B0 to Ds(*)+rho-, and B0 to Ds(*)-K(*)+ (open access)

Measurement of the Branching Fractions of the Rare Decays B0 to Ds(*)+pi-,B0 to Ds(*)+rho-, and B0 to Ds(*)-K(*)+

The authors report the measurement of the branching fractions of the rare decays B{sup 0} {yields} D{sub s}{sup (*)+} {pi}{sup -}, B{sup 0} {yields} D{sub s}{sup (*)+} {rho}{sup -}, and B{sup 0} {yields} D{sub s}{sup (*)-} K{sup (*)+} in a sample of 381 x 10{sup 6} {Upsilon}(4S) decays into B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. They present evidence for the decay B{sup 0} {yields} D{sub s}{sup -} K*{sup +} and the vector-vector decays B{sup 0} {yields} D{sub s}{sup *+} {rho}{sup -} and B{sup 0} {yields} D{sub s}{sup *-} K{sup *+}, as well as the first measurement of the vector meson polarization in these decays. They also determine the ratios of the CM-suppressed to CKM-favored amplitudes r(D{sup (*)}{pi}) and r(D{sup (*)}{rho}) in decays B{sup 0} {yields} D{sup (*)}{sup {+-}}{pi}{sup {-+}} and B{sup 0} {yields} D{sup (*)}{sup {+-}}{rho}{sup {-+}}, and comment on the prospects for measuring the Cp observable sin(2{beta} + {gamma}).
Date: April 16, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Object Type: Article
System: The UNT Digital Library
Search for New Physics Beyond the Standard Model at BaBar (open access)

Search for New Physics Beyond the Standard Model at BaBar

A review of selected recent BaBar results are presented that illustrate the ability of the experiment to search for physics beyond the standard model. The decays B {yields} {tau}{nu} and B {yields} s{gamma} provide constraints on the mass of a charged Higgs. Searches for Lepton Flavour Violation could provide a clear signal for beyond the standard model physics. Babar does not observe any signal for New Physics with the current dataset.
Date: April 16, 2008
Creator: Barrett, Matthew & U., /Brunel
Object Type: Article
System: The UNT Digital Library
CALCULATION OF DEMONSTRATION BULK VITRIFICATION SYSTEM MELTER INLEAKAGE AND OFF-GAS GENERATION RATE (open access)

CALCULATION OF DEMONSTRATION BULK VITRIFICATION SYSTEM MELTER INLEAKAGE AND OFF-GAS GENERATION RATE

The River Protection Project (RPP) mission is to safely store, retrieve, treat, immobilize, and dispose of the Hanford Site tank waste. The Demonstration Bulk Vitrification System (DBVS) is a research and development project whose objective is to demonstrate the suitability of Bulk Vitrification treatment technology waste form for disposing of low-activity waste from the Tank Farms. The objective of this calculation is to determine the DBVS melter inleakage and off-gas generation rate based on full scale testing data from 38D. This calculation estimates the DBVS melter in leakage and gas generation rate based on test data. Inleakage is estimated before the melt was initiated, at one point during the melt, and at the end of the melt. Maximum gas generation rate is also estimated.
Date: April 16, 2008
Creator: TH, MAY
Object Type: Report
System: The UNT Digital Library
Making Amines Strong Bases: Thermodynamic Stabilization ofProtonated Guests in a Highly-Charged Supramolecular Host (open access)

Making Amines Strong Bases: Thermodynamic Stabilization ofProtonated Guests in a Highly-Charged Supramolecular Host

A highly-charged, cavity-containing supramolecular assembly formed by metal-ligand interactions acts as a host to dramatically shift the effective basicity of encapsulated protonated amine guests. The scope of encapsulated protonated amine and phosphine guests shows size selectivity consistent with a constrained binding environment. Protonation of the encapsulated guests is confirmed by {sup 31}P NMR studies, mass spectrometry studies, and the pH dependence of guest encapsulation. Rates of guest self-exchange were measured using the Selective Inversion Recovery method and were found to correlate with the size rather than the basicity of the guests. The activation parameters for guest self-exchange are consistent with the established mechanism for guest exchange. The binding constants of the protonated amines are then used to calculate the effective basicity of the encapsulated amines. Depending on the nature of the guest, shifts in the effective basicities of the encapsulated amines of up to 4.5 pK{sub a} units are observed, signifying a substantial stabilization of the protonated form of the guest molecule and effectively making phosphines and amines strong bases.
Date: April 16, 2007
Creator: Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
Object Type: Article
System: The UNT Digital Library
Correlation between Strand Stability and Magnet Performance (open access)

Correlation between Strand Stability and Magnet Performance

Magnet programs at BNL, LBNL and FNAL have observed instabilities in high J{sub c} Nb{sub 3}Sn strands and magnets made from these strands. This paper correlates the strand stability determined from a short sample-strand test to the observed magnet performance. It has been observed that strands that carry high currents at high fields (greater than 10T) cannot sustain these same currents at low fields (1-3T) when the sample current is fixed and the magnetic field is ramped. This suggests that the present generation of strand is susceptible to flux jumps (FJ). To prevent flux jumps from limiting stand performance, one must accommodate the energy released during a flux jump. To better understand FJ this work has focused on wire with a given sub-element diameter and shows that one can significantly improve stability by increasing the copper conductivity (higher residual resistivity ratio, RRR, of the Cu). This increased stability significantly improves the conductor performance and permits it to carry more current.
Date: April 16, 2005
Creator: Dietderich, Daniel R.; Bartlett, Scott E.; Caspi, Shlomo; Ferracin, Paolo; G ourlay, Stephen A.; Higley, Hugh C. et al.
Object Type: Article
System: The UNT Digital Library
Optimization of sparse matrix-vector multiplication on emerging multicore platforms (open access)

Optimization of sparse matrix-vector multiplication on emerging multicore platforms

We are witnessing a dramatic change in computer architecture due to the multicore paradigm shift, as every electronic device from cell phones to supercomputers confronts parallelism of unprecedented scale. To fully unleash the potential of these systems, the HPC community must develop multicore specific optimization methodologies for important scientific computations. In this work, we examine sparse matrix-vector multiply (SpMV)--one of the most heavily used kernels in scientific computing--across a broad spectrum of multicore designs. Our experimental platform includes the homogeneous AMD dual-core and Intel quad-core designs, as well as the highly multithreaded Sun Niagara and heterogeneous STI Cell. We present several optimization strategies especially effective for the multicore environment, and demonstrate significant performance improvements compared to existing state-of-the-art serial and parallel SpMV implementations. Additionally, we present key insights into the architectural tradeoffs of leading multicore design strategies, in the context of demanding memory-bound numerical algorithms.
Date: April 16, 2007
Creator: Williams, S.; Oliker, L.; Vuduc, R.; Shalf, J.; Yelick, K. & Demmel, J.
Object Type: Article
System: The UNT Digital Library
Asymmetric Intramolecular Alkylation of Chiral Aromatic Imines via Catalytic C-H Bond Activation (open access)

Asymmetric Intramolecular Alkylation of Chiral Aromatic Imines via Catalytic C-H Bond Activation

The asymmetric intramolecular alkylation of chiral aromatic aldimines, in which differentially substituted alkenes are tethered meta to the imine, was investigated. High enantioselectivities were obtained for imines prepared from aminoindane derivatives, which function as directing groups for the rhodium-catalyzed C-H bond activation. Initial demonstration of catalytic asymmetric intramolecular alkylation also was achieved by employing a sterically hindered achiral imine substrate and catalytic amounts of a chiral amine.
Date: April 16, 2007
Creator: Watzke, Anja; Wilson, Rebecca; O'Malley, Steven; Bergman, Robert & Ellman, Jonathan
Object Type: Article
System: The UNT Digital Library
Radiological Contingency Planning for the Mars Science Laboratory Launch (open access)

Radiological Contingency Planning for the Mars Science Laboratory Launch

This paper describes the contingency planning for the launch of the Mars Science Laboratory scheduled for the 21-day window beginning on September 15, 2009. National Security Technologies, LLC (NSTec), based in Las Vegas, Nevada, will support the U.S. Department of Energy (DOE) in its role for managing the overall radiological contingency planning support effort. This paper will focus on new technologies that NSTec’s Remote Sensing Laboratory (RSL) is developing to enhance the overall response capability that would be required for a highly unlikely anomaly. This paper presents recent advances in collecting and collating data transmitted from deployed teams and sensors. RSL is responsible to prepare the contingency planning for a range of areas from monitoring and assessment, sample collection and control, contaminated material release criteria, data management, reporting, recording, and even communications. The tools RSL has available to support these efforts will be reported. The data platform RSL will provide shall also be compatible with integration of assets and field data acquired with other DOE, National Aeronautics and Space Administration, state, and local resources, personnel, and equipment. This paper also outlines the organizational structure for response elements in radiological contingency planning.
Date: April 16, 2008
Creator: Paul Guss, Robert Augdahl, Bill Nickels, Cassandra Zellers
Object Type: Article
System: The UNT Digital Library
Tests of non-local interferences in kaon physics at asymmetric [phi]-factories (open access)

Tests of non-local interferences in kaon physics at asymmetric [phi]-factories

Tests of non-local interference effects in the two-kaon system are proposed. The first kind of tests consists of measuring the amount of destructive interference between K[sub S] [yields] K[sub L] regeneration processes of two distant kaons. The second kind deals with constructive interference. These tests could be performed at an asymmetric [phi]-factory. Estimates are given of the number of events predicted by orthodox quantum mechanics and kaon regeneration theory in various suitable experimental conditions. The impact on local theories if the predictions of quantum mechanics hold is discussed.
Date: April 16, 1993
Creator: Eberhard, P.H.
Object Type: Article
System: The UNT Digital Library
Low pressure gas filling of laser fusion microspheres (open access)

Low pressure gas filling of laser fusion microspheres

In our laser fusion microsphere production, large, thin gel-microspheres are formed before the chemicals are fused into glass. In this transient stage,, the gel-microspheres are found to be highly permeable to argon and many other inert gases. When the gel transforms to glass, the argon gas, for example, is trapped within to form argon filled, fusion target quality, glass microspheres. On the average, the partial pressure of the argon fills attained in this process is around 2 x 10/sup 4/ Pa at room temperature.
Date: April 16, 1979
Creator: Koo, J.C.; Dressler, J.L. & Hendricks, C.D.
Object Type: Article
System: The UNT Digital Library
The structure and properties of grain boundaries in B2 ordered alloys (open access)

The structure and properties of grain boundaries in B2 ordered alloys

This report covers the period from April 1, 1989 to March 30, 1990. During this period further extrusions of fine-grained alloys of FeAl and NiAl with different aluminum contents were produced. Thus far, researchers have (1) completed room temperature mechanical testing which shows that the yield strength, {sigma}{sub y}, of FeAl shows a minimum near Fe-45Al while that for NiAl increases with increasing (nickel-rich) deviation from stoichiometry; (2) showed that the grain boundary strengthening parameter, k, in the Hall-Petch relationship, {sigma}{sub y} = {sigma}{sub 0} + k d{sup {minus}{1/2}} (where {sigma}{sub 0} is the lattice resistance and d the grain size), in FeAl shows a minimum at Fe-45Al whilst in NiAl it decreases with increasing deviation from stoichiometry; (3) studied grain boundary chemistry in near-stoichiometric NiAl and FeAl using scanning Auger electron spectroscopy at Oak Ridge National Laboratory, with the aid of Mr. R.A. Padgett, Jr.; studied grain boundary chemistry using EDS and Z-contrast imaging on field emission gun high resolution scanning transmission electron microscopes; (5) continued in-situ straining experiments in the transmission electron microscope to examine dislocation/grain boundary interactions; (6) examined dislocation structures in lightly-deformed NiAl and FeAl and, based on observations in the latter, proposed a mechanism for …
Date: April 16, 1990
Creator: Baker, I.
Object Type: Report
System: The UNT Digital Library