Modal photon densities (open access)

Modal photon densities

The short wavelength laser code XRASER uses line raidation fields whose dimensions are photons/mode. In this document, we discuss modal photon densities and provide formulas relating these units to units more familiar to the LLNL community.
Date: June 21, 1982
Creator: Hagelstein, P.L.
Object Type: Report
System: The UNT Digital Library
X-ray diffraction study of reversible deformation mechanisms in the aged uranium-6. 5 niobium alloy (open access)

X-ray diffraction study of reversible deformation mechanisms in the aged uranium-6. 5 niobium alloy

The x-ray diffraction (XRD) data from 200/sup 0/C/2h-aged uranium-6.5 wt % niobium (U-6.5Nb) alloys, taken under stress as a function of strain, revealed a gamma-zero (..gamma../sup 0/)..-->.. alpha prime-prime (..cap alpha..'') thermoelastic martensitic phase transformation. It was concluded that the primary reversible deformation modes consisted of the movement of ..gamma../sup 0//..cap alpha..'' interphase interfaces and ..cap alpha..'' intervariant interfaces. Specimen elasticity at low strains was associated with the retreat of interphase interfaces. At higher strains, interphase interfaces did not recover significantly on unloading, and elasticity was due primarily to the retreat of ..cap alpha..'' intervariant interfaces.
Date: June 21, 1985
Creator: Carpenter, D.A.
Object Type: Report
System: The UNT Digital Library
Literature search for the non-aqueous separation of zinc from fuel rod cladding. [After dissolution in liquid metal] (open access)

Literature search for the non-aqueous separation of zinc from fuel rod cladding. [After dissolution in liquid metal]

This report reviews the literature of processes for the nonaqueous separation of zinc from dissolved fuel assembly cladding. The processes considered were distillation, pyrochemical processing, and electrorefining. The last two techniques were only qualitatively surveyed while the first, distillation, was surveyed in detail. A survey of available literature from 1908 through 1978 on the distillation of zinc was performed. The literature search indicated that a zinc recovery rate in excess of 95% is possible; however, technical problems exist because of the high temperatures required and the corrosive nature of liquid zinc. The report includes a bibliography of the surveyed literature and a computer simulation of vapor pressures in binary systems. 129 references.
Date: June 21, 1980
Creator: Sandvig, R. L.; Dyer, S. J.; Lambert, G. A. & Baldwin, C. E.
Object Type: Report
System: The UNT Digital Library
EG G sampling program results FY 1989 (open access)

EG G sampling program results FY 1989

Thirty-three waste drums were returned to Rocky Flats in support of EG G Idaho's quality control program for the Stored Waste Examination Pilot Plant. The drums were opened and examined in the size reduction facility at the Rocky Flats Plant. Contents of each drum were consistent with the Item Description Codes; however, four sludge drums and one combustible drum contained free liquids. These five drums failed to meet the Waste Isolation Pilot Plant and the Department of Transporation criteria. The proper amount of cement was not used in the sludge drums. A cemented layering process, which also contributed to accumulation of free liquid, is no longer used when cementing sludges at the Rocky Flats Plant. The drum of combustibles contained a polyethylene bottle with a small amount of liquid sludge inside. 2 refs., 2 tabs.
Date: June 21, 1991
Creator: Watson, L.E.
Object Type: Report
System: The UNT Digital Library
Determination of somatic mutations in human erythrocytes by cytometry (open access)

Determination of somatic mutations in human erythrocytes by cytometry

Flow cytometric assays of human erythrocytes labeled with monoclonal antibodies specific for glycophorin A were used to enumerate variant cells that appear in peripheral blood as a result of somatic gene-loss mutations in erythrocyte precursor cells. The assay was performed on erythrocytes from 10 oncology patients who had received at least one treatment from radiation or mutagenic chemotherapy at least 3 weeks before being assayed. The patients were suffering from many different malignancies (e.g., breast, renal, bone, colon and lung), and were treated with several different mutagenic therapeutics (e.g., cisplatinum, adriamycin, daunomycin, or cyclophosphamide). The frequency of these variant cells is an indication of the amount of mutagenic damage accumulated in the individual's erythropoietic cell population. Comparing these results to HPRT clonogenic assays, we find similar baseline frequencies of somatic mutation as well as similar correlation with mutagenic exposures. 9 refs., 3 figs., 1 tab.
Date: June 21, 1985
Creator: Jensen, R.H.; Langlois, R.G. & Bigbee, W.L.
Object Type: Article
System: The UNT Digital Library
Relaxation of neodymium in a weakly ionized expanding plasma (open access)

Relaxation of neodymium in a weakly ionized expanding plasma

The laser resonance absorption technique has been used to determine the relaxation rate of electronically excited neodymium vapor during its expansion into vacuum. Significant increases of population into ground and 1128 cm/sup -1/ levels were found. Analysis shows that interaction between excited metastable atoms and electrons are much more important for relaxation than atom-atom collisions. The final population of neodymium appears to be frozen at a temperature lower than the surface temperature of melt.
Date: June 21, 1977
Creator: Chen, H. L.; Bedford, R.; Borzileri, C.; Brunner, W. & Hayes, M.
Object Type: Article
System: The UNT Digital Library
SLC ir conceptual design (open access)

SLC ir conceptual design

Work on a one interaction-region, push-pull conceptual design for the SLC is described. The concept which has received the most attention is described. It is a below-ground hall - a 15 m deep rectangular pit covered by a surface building which houses counting rooms, power supplies, cryogenics and other auxiliary equipment. (LEW)
Date: June 21, 1982
Creator: Keller, L.P.
Object Type: Report
System: The UNT Digital Library
Compensatory Paracrine Mechanisms That Define The Urothelial Response to Injury in Partial Bladder Outlet Obstruction (open access)

Compensatory Paracrine Mechanisms That Define The Urothelial Response to Injury in Partial Bladder Outlet Obstruction

Diseases and conditions affecting the lower urinary tract are a leading cause of dysfunctional sexual health, incontinence, infection, and kidney failure. The growth, differentiation, and repair of the bladder's epithelial lining are regulated, in part, by fibroblast growth factor (FGF)-7 and -10 via a paracrine cascade originating in the mesenchyme (lamina propria) and targeting the receptor for FGF-7 and -10 within the transitional epithelium (urothelium). The FGF-7 gene is located at the 15q15-q21.1 locus on chromosome 15 and four exons generate a 3.852-kb mRNA. Five duplicated FGF-7 gene sequences that localized to chromosome 9 were predicted not to generate functional protein products, thus validating the use of FGF-7-null mice as an experimental model. Recombinant FGF-7 and -10 induced proliferation of human urothelial cells in vitro and transitional epithelium of wild-type and FGF-7-null mice in vivo.To determine the extent that induction of urothelial cell proliferation during the bladder response to injury is dependent on FGF-7, an animal model of partial bladder outlet obstruction was developed. Unbiased stereology was used to measure the percentage of proliferating urothelial cells between obstructed groups of wild-type and FGF-7-null mice. The stereological analysis indicated that a statistical significant difference did not exist between the two groups, …
Date: June 21, 2007
Creator: Bassuk, James; Lendvay, Thomas S.; Sweet, Robert; Han, Chang-Hee; Soygur, Tarkan; Cheng, Jan-Fang et al.
Object Type: Article
System: The UNT Digital Library
Toward a Deeper Understanding of Plutonium (open access)

Toward a Deeper Understanding of Plutonium

Plutonium is a very complex element lying near the middle of the actinide series. On the lower atomic number side of Pu is the element neptunium; its 5f electrons are highly delocalized or itinerant, participating in metallic-like bonding. The electrons in americium, the element to the right of Pu, are localized and do not participant significantly in the bonding. Plutonium is located directly on this rather abrupt transition. In the low-temperature {alpha} phase ground state, the five 5f electrons are mostly delocalized leading to a highly dense monoclinic crystal structure. Increases in temperature take the unalloyed plutonium through a series of five solid-state allotropic phase transformations before melting. One of the high temperature phases, the close-packed face centered cubic {delta} phase, is the least dense of all the phases, including the liquid. Alloying the Pu with Group IIIA elements such as aluminum or gallium retains the {delta} phase in a metastable state at ambient conditions. Ultimately, this metastable {delta} phase will decompose via a eutectoid transformation to {alpha} + Pu{sub 3}Ga. These low solute-containing {delta}-phase Pu alloys are also metastable with respect to low temperature excursions or increases in pressure and will transform to a monoclinic crystal structure at low …
Date: June 21, 2007
Creator: Schwartz, A J & Wolfer, W G
Object Type: Article
System: The UNT Digital Library
Unified Model of Dynamic Forced Barrier Crossing in Single Molecules (open access)

Unified Model of Dynamic Forced Barrier Crossing in Single Molecules

Thermally activated barrier crossing in the presence of an increasing load can reveal kinetic rate constants and energy barrier parameters when repeated over a range of loading rates. Here we derive a model of the mean escape force for all relevant loading rates--the complete force spectrum. Two well-known approximations emerge as limiting cases; one of which confirms predictions that single-barrier spectra should converge to a phenomenological description in the slow loading limit.
Date: June 21, 2007
Creator: Friddle, R W
Object Type: Article
System: The UNT Digital Library
On prediction of wind-borne plumes with simple models of turbulenttransport (open access)

On prediction of wind-borne plumes with simple models of turbulenttransport

The dispersion of pollutants from the ground by turbulent winds is difficult to model in general. However, for flat homogeneous terrain and steady wind conditions, if the wind profile is modeled with a power-law dependence on height, the advection-dispersion equation has an exact solution. In this paper the analytical solution is compared to a numerical simulation of the coupled air-ground system for a leaking underground gas storage, with a power-law velocity profile that was fit to the logarithmic velocity profile used in the simulation. The two methods produced similar results far from the boundaries, but the boundary conditions had a strong effect; the simulation imposed boundary conditions at the edge of a finite domain while the analytic solution imposes them at infinity. The reverse seepage from air to ground was shown in the simulation to be very small, and the sharp contrast between time scales suggests that air and ground can be modeled separately, with gas emissions from the ground model used as inputs to the air model.
Date: June 21, 2006
Creator: Schwarz, Katherine; Patzek, Tad & Silin, Dmitriy
Object Type: Article
System: The UNT Digital Library
Test of weak and strong factorization in nucleus-nucleuscollisions atseveral hundred MeV/nucleon (open access)

Test of weak and strong factorization in nucleus-nucleuscollisions atseveral hundred MeV/nucleon

Total and partial charge-changing cross sections have been measured for argon projectiles at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained, using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cross sections; preliminary cross section values obtained for carbon, neon and silicon at 290 and 400 MeV/nucleon and iron at 400 MeV/nucleon, in carbon, aluminum, copper, tin and lead targets have been also used for testing these properties. Two different analysis methods were applied and both indicated that these properties are valid, without any significant difference between weak and strong factorization. The factorization parameters have then been calculated and analyzed in order to find some systematic behavior useful for modeling purposes.
Date: June 21, 2006
Creator: La Tessa, Chiara; Sihver, Lembit; Zeitlin, Cary; Miller, Jack; Guetersloh, Stephen; Heilbronn, Lawrence et al.
Object Type: Article
System: The UNT Digital Library
Nuclear Stewardship Research. (open access)

Nuclear Stewardship Research.

This report covers the period from June 2005 through May 2006. During this, the third year of our program, our research has focused mainly on applying the surrogate reaction technique and our newly developed surrogate ratio method to deduce neutron induced fission cross sections on uranium nuclei. The year has been marked by continued scientific progress, by the arrival of new personnel, by a growth in the numbers of students working in the group and by a continuation of our experimental program and close collaboration with staff and scientists from Lawrence Livermore National Laboratory and from Lawrence Berkeley National Laboratory.
Date: June 21, 2006
Creator: Beausang, C. W.
Object Type: Report
System: The UNT Digital Library
Coherent Beam Stability in the Low Momentum Compaction Lattice (open access)

Coherent Beam Stability in the Low Momentum Compaction Lattice

The beam dynamics for a quasi-isochronous lattice differs from that in the usual case of a lattice with a large positive momentum compaction factor. In particular, the quasi-isochronous lattice allows us to double the number of bunches which may be an attractive option for colliders. However, microwave instability and, as we show, longitudinal head-tail instability set the threshold for the beam current.
Date: June 21, 2006
Creator: Heifets, S. & Novokhatski, A.
Object Type: Article
System: The UNT Digital Library
Temporal Development of Ion Beam Mean Charge State in PulsedVacuum Arc Ion Sources (open access)

Temporal Development of Ion Beam Mean Charge State in PulsedVacuum Arc Ion Sources

Vacuum arc ion sources, commonly also known as "Mevva" ionsources, are used to generate intense pulsed metal ion beams. It is knownthat the mean charge state of the ion beam lies between 1 and 4,depending on cathode material, arc current, arc pulse duration, presenceor absence of magnetic field at the cathode, as well background gaspressure. A characteristic of the vacuum arc ion beam is a significantdecrease in ion charge state throughout the pulse. This decrease can beobserved up to a few milliseconds, until a "noisy" steady-state value isestablished. Since the extraction voltage is constant, a decrease in theion charge state has a proportional impact on the average ion beamenergy. This paper presents results of detailed investigations of theinfluence of arc parameters on the temporal development of the ion beammean charge state for a wide range of cathode materials. It is shown thatfor fixed pulse duration, the charge state decrease can be reduced bylower arc current, higher pulse repetition rate, and reduction of thedistance between cathode and extraction region. The latter effect may beassociated with charge exchange processes in the dischargeplasma.
Date: June 21, 2007
Creator: Oks, Efim M.; Yushkov, Georgy Yu. & Anders, Andre
Object Type: Article
System: The UNT Digital Library
High Gradient Induction Accelerator (open access)

High Gradient Induction Accelerator

A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.
Date: June 21, 2007
Creator: Caporaso, G. J.; Sampayan, S.; Chen, Y.; Blackfield, D.; Harris, J.; Hawkins, S. et al.
Object Type: Article
System: The UNT Digital Library
A Novel Approach to Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost (open access)

A Novel Approach to Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As …
Date: June 21, 2007
Creator: Chizmeshya, Andrew V. G.; McKelvy, Michael J.; Squires, Kyle; Carpenter, Ray W. & Bearat, Hamdallah
Object Type: Report
System: The UNT Digital Library
Effective Error Bounds in Euler-Maclaurin-Based QuadratureSchemes (open access)

Effective Error Bounds in Euler-Maclaurin-Based QuadratureSchemes

We analyze the behavior of Euler-Maclaurin-basedintegrationschemes with the intention of deriving accurate andeconomicestimations of the error term.
Date: June 21, 2005
Creator: Bailey, David H. & Borwein, Jonathan M.
Object Type: Report
System: The UNT Digital Library
A "Snowflake" Divertor and its Properties (open access)

A "Snowflake" Divertor and its Properties

Handling the power and particle exhaust in fusion reactors based on tokamaks is a challenging problem [1,2]. To bring the energy flux to the divertor plates to an acceptable level (< 10 MW/m2), it is desirable to significantly increase poloidal flux expansion in the divertor area. Some recent ideas include that of a so-called X divertor [3] and a 'snowflake' divertor [4]. We use an acronym SF to designate the latter. In this paper we concentrate on the SF divertor. The general idea behind this configuration is that, by a proper selection of divertor (poloidal field) coils, one can make the null point of the second, not of the first order as in the standard divertor. The separatrix in the vicinity of the X point then acquires a characteristic hexapole structure (Fig. 1), reminiscent of a snowflake, whence the name. The fact that the field has a second-order null, leads to a significant increase of the flux expansion. It was noted in Ref. [4] that the SF configuration is topologically unstable: if the current in the divertor coils is somewhat higher than the one that provides the SF configuration, it becomes a single-null X-point configuration. Conversely, if the coil current …
Date: June 21, 2007
Creator: Ryutov, D.
Object Type: Article
System: The UNT Digital Library
Immiscibility in the Nickel Ferrite-Zinc Ferrite Spinel Binary (open access)

Immiscibility in the Nickel Ferrite-Zinc Ferrite Spinel Binary

Immiscibility in the trevorite (NiFe{sub 2}O{sub 4}) - franklinite (ZnFe{sub 2}O{sub 4}) spinel binary is investigated by reacting 1:1:2 molar ratio mixtures of NiO, ZnO and Fe{sub 2}O{sub 3} in a molten salt solvent at temperatures in the range 400-1000 C. Single phase stability is demonstrated down to about 730 C (the estimated consolute solution temperature, T{sub cs}). A miscibility gap/solvus exists below Tcs. The solvus becomes increasingly asymmetric at lower temperatures and extrapolates to n - values = 0.15, 0.8 at 300 C. A thermodynamic analysis, which accounts for changes in configurational and magnetic ordering entropies during cation mixing, predicts solvus phase compositions at room temperature in reasonable agreement with those determined by extrapolation of experimental results. The delay between disappearance of magnetic ordering above T{sub C} = 590 C (for NiFe{sub 2}O{sub 4}) and disappearance of a miscibility gap at T{sub cs} is explained by the persistence of long-range ordering correlations in a quasi-paramagnetic region above T{sub C}.
Date: June 21, 2006
Creator: Ziemniak, SE; Gaddipati, AR; Sander, PC & Rice, SB
Object Type: Article
System: The UNT Digital Library
The Influence of the In-Situ Clad Staining on the Corrosion of Zircaloy in PWR Water Environment (open access)

The Influence of the In-Situ Clad Staining on the Corrosion of Zircaloy in PWR Water Environment

Zircaloy cladding tubes strain in-situ during service life in the corrosive environment of a Pressurized Water Reactor for a variety of reasons. First, the tube undergoes stress free growth due to the preferential alignment of irradiation induced vacancy loops on basal planes. Positive strains develop in the textured tubes along prism orientations while negative strains develop along basal orientations (Reference (a)). Second, early in life, free standing tubes will often shrink by creep in the diametrical direction under the external pressure of the water environment, but potentially grow later in life in the diametrical direction once the expanding fuel pellet contacts the cladding inner wall (Reference (b)). Finally, the Zircaloy cladding absorbs hydrogen as a by product of the corrosion reaction (Reference (c)). Once above the solubility limit in Zircaloy, the hydride precipitates as zirconium hydride (References (c) through (j)). Both hydrogen in solid solution and precipitated as Zirconium hydride cause a volume expansion of the Zircaloy metal (Reference (k)). Few studies are reported on that have investigated the influence that in-situ clad straining has on corrosion of Zircaloy. If Zircaloy corrosion rates are governed by diffusion of anions through a thin passivating boundary layer at the oxide-to-metal interface (References …
Date: June 21, 2001
Creator: Kammenzind, B.F., Eklund, K.L. and Bajaj, R.
Object Type: Report
System: The UNT Digital Library
CASIM predictions of Meson West Tevatron target soil activation (open access)

CASIM predictions of Meson West Tevatron target soil activation

A new Meson West Target has been proposed for Tevatron II. The dump design proposed by David Eartly is shown. A longitudinal side view of the dump and the shield for target produced muons is shown. The core of the dump is seen to be a copper plate surrounding the beam. The copper is surrounded by iron, which is in turn shielded by concrete. The tunnel is embedded in sand and gravel. The sand and gravel within 3' of the concrete is continuously drained by underdrains. Soil below the top of the underdrains is not considered to be protected. Activity produced in the unprotected soil below can be leached out, transported to the aquifer, and subsequently reach public water supplies. It is the activation of this unprotected soil which is of particular interest. Since the specific type of beryllium target to be used has not yet been decided, and since it would only reduce the resultant soil activation, I have chosen to ignore it and to presume that all the targetted intensity is lost on the dump. I have made CASIM calculations of the levels of soil activation to be expected using the proposed dump design. Since the activation of …
Date: June 21, 1982
Creator: Gronemeyer, S.A.
Object Type: Report
System: The UNT Digital Library
Configuration of Tatum Salt Dome, Lamar County, Mississippi. Technical Letter: Dribble-1 (open access)

Configuration of Tatum Salt Dome, Lamar County, Mississippi. Technical Letter: Dribble-1

This report addresses the configuration of Tatum Salt Dome, Lamar County, Mississippi.
Date: June 21, 1961
Creator: Black, R. A. & Twenhofel, W. S.
Object Type: Report
System: The UNT Digital Library
SAVANNAH RIVER TECHNOLOGY CENTER MONTHLY REPORT AUGUST 1992 (open access)

SAVANNAH RIVER TECHNOLOGY CENTER MONTHLY REPORT AUGUST 1992

'This monthly report summarizes Programs and Accomplishments of the Savannah River Technology Center in support of activities at the Savannah River Site. The following categories are addressed: Reactor, Tritium, Separations, Environmental, Waste Management, General, and Items of Interest.'
Date: June 21, 1999
Creator: Ferrell, J.M.
Object Type: Report
System: The UNT Digital Library