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Report on Analysis of Forest Floor Bulk Density and Depth at the Savannah River Site.

Description: The forest floor data from the Savannah River Site consists of two layers, the litter layer and the duff layer. The purpose for the study was to determine bulk density conversion factors to convert litter and duff depth values in inches to forest floor fuel values in tons per acre. The primary objective was to collect litter and duff samples to adequately characterize forest floor depth and bulk density for combinations of 4 common forest types (loblolly/slash pine, longleaf pine, pine and hardwood mix, upland hardwood), 3 age classes (5-20, 20-40, 40+ years old) and 3 categories of burning history (0-3, 3-10, 10+ years since last burn).
Date: October 1, 2005
Creator: Parresol, Bernard R.
Partner: UNT Libraries Government Documents Department

Forest floor bulk density and depth at Savannah River - Draft Final Report.

Description: Knowing the amount of biomass across a landscape is becoming increasingly important to fire managers as new fuel and fire management decision support systems come on line. Fire managers rarely have the time or funding available to sample fuels operationally and often depend upon mean values for critical variables whose variation is often associated with simple stand characteristics such as age, forest type, time since last burn, stocking, or site, and other easily measured variables. This report outlines a study to collect and analyze litter and duff bulk density samples for developing a simple predictive tool to estimate forest floor fuel loading based on simple stand characteristics.
Date: December 28, 2004
Creator: Maier, Brian; Ottmar, Roger & Wright, Clint
Partner: UNT Libraries Government Documents Department

Segmented Aluminum Honeycomb Characteristics in T-Direction, Dynamic Crush Environments

Description: Thirteen segmented aluminum honeycomb samples (5 in. diameter and 1.5 in. height) have been crushed in an experimental configuration that uses a drop table impact machine. The 38.0 pcf bulk density samples are a unique segmented geometry that allows the samples to be crushed while maintaining a constant cross-sectional area. A crush weight of 175 lb was used to determine the rate sensitivity of the honeycomb's highest strength orientation, T-direction, in a dynamic environment of {approx}50 fps impact velocity. Experiments were conducted for two honeycomb manufacturers and at two temperatures, ambient and +165 F. Independent measurements of the crush force were made with a custom load cell and a force derived from acceleration measurements on the drop table using the Sum of Weighted Accelerations Technique with a Calibrated Force (SWAT-CAL). Normalized stress-strain curves for all thirteen experiments are included and have excellent repeatability. These data are strictly valid for material characteristics in the T orientation because the cross-sectional area of the honeycomb did not change during the crush. The dynamic crush data have a consistent increase in crush strength of {approximately}7--19% as compared to quasi-static data and suggest that dynamic performance may be inferred from static tests. An uncertainty analysis estimates the error in these data is {+-} 11%.
Date: August 23, 2000
Partner: UNT Libraries Government Documents Department

Carbon Sequestration on Surface Mine Lands

Description: A major effort this quarter was to inventory all the planted areas to evaluate the diameter and height growth as well as determine survival rates. Soil bulk density and compaction continue to be evaluated on all the areas to determine the effects on tree growth and survival. The hydrologic quantity and quality are continuously monitored and quantified. Much effort was also expended in preparing technical presentations for professional meeting and for the preparation of the final project report.
Date: May 2, 2006
Creator: Graves, Donald H.; Barton, Christopher; Sweigard, Richard & Warner, Richard
Partner: UNT Libraries Government Documents Department

Carbon Sequestration on Surface Mine Lands

Description: A major effort this quarter was to inventory all the planted areas to evaluate the diameter and height growth as well as determine survival rates. Soil bulk density and compaction continue to be evaluated on all the areas to determine the effects on tree growth and survival. The hydrologic quantity and quality are continuously monitored and quantified. Much effort was also expended in preparing technical presentations for professional meeting and field trips for a variety of audiences.
Date: December 7, 2005
Creator: Graves, Donald H.; Barton, Christopher; Sweigard, Richard & Warner, Richard
Partner: UNT Libraries Government Documents Department

Mechanical behavior of robocast alumina

Description: Direct fabrication of alumina parts by robocasting was completed. This method is based on three-dimensional deposition of binderless aqueous alumina slurries. Parts were made with different deposition paths and mechanical testing performed to determine the effects of bead alignment. Properties were also compared to alumina processed more traditionally.
Date: December 1, 1998
Creator: Denham, H.B.; Cesarano, J. III; King, B.H. & Calvert, P.
Partner: UNT Libraries Government Documents Department

Laboratory analysis of soil hydraulic properties of CDBM 2 and CDBM 3 samples

Description: Daniel B. Stephens & Associates, Inc. (DBS&A) was requested by Dr. Alan Stoker of Los Alamos National Laboratory to perform laboratory analysis for properties of CDBM 2 and CDBM 3 samples, as outlined in Subcontract No. 9-XTI-027EE-1. The scope of work included conducting tests for the following properties: Initial moisture content, dry bulk density, and calculated porosity; Saturated hydraulic conductivity; Moisture characteristics; Unsaturated hydraulic properties (calculated); and Transient outflow.
Date: December 1, 1992
Partner: UNT Libraries Government Documents Department

Point Defects in Binary Laves-Phase Alloys

Description: Point defect mechanisms in the binary C15 NbCr{sub 2} and NbCo{sub 2}, and C14 NbFe{sub 2} systems on both sides of stoichiometry was studied and clarified by both bulk density and X-ray lattice parameter measurements. It was found that the vacancy concentrations in these systems after quenching from 1000 C are essentially zero. The constitutional defects on both sides of stoichiometry for these systems were found to be of the anti-site type in comparison with the model predictions. However, thermal vacancies exhibiting a maximum at the stoichiometric composition were obtained in NbCr{sub 2} laves phase alloys after quenching from 1400 C. These could be completely eliminated by annealing at 1000 C. Anti-site hardening was found on both sides of stoichiometry for all three Laves phase systems studied. Furthermore, the thermal vacancies in NbCr{sub 2} alloys after quenching from 1400 C were found to soften the Laves phase. The anti-site hardening of the Laves phases is similar to that of the B2 compounds, while the thermal vacancy softening is unique to the Laves phase. Both the anti-site defects and thermal vacancies do not significantly affect the fracture toughness of the Laves phases.
Date: November 30, 1998
Creator: Liaw, P.K.; Liu, C.T.; Pike, L.M. & Zhu, J.H.
Partner: UNT Libraries Government Documents Department

TEPIC -- A new high temperature structural foam

Description: The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 C, are reported. In each of these respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. The authors' approach was to combine chemistries known to form thermally stable products. The principal polymerization products are an oxizolidinone produced by the reaction of the isocyanate with the epoxide and isocyanurate rings formed by the trimerization of the isocyanate. Processing has been examined and large-scale production is discussed in detail. Compared to APO-BMI processing, TEPIC processing is facile and economical. The structure of the foam resembles a traditional rigid polyurethane foam rather than that of the APO-BMI. That is, the foam is comprised of a continuous resin phase rather than weakly bonded glass microballoons. At a density of 0.42 g/cm{sup 3} or greater, maximum pore size in TEPIC was less than 2 mm, as required for the application.
Date: October 1, 1998
Creator: Whinnery, L. L.; Goods, S. H.; Tootle, M. L. & Neuschwanger, C. L.
Partner: UNT Libraries Government Documents Department

Development for the Optional Use of Circular Core Tubes with the High Shear Stress Flume

Description: In this study, the erosion rates of four reconstituted sediments in both rectangular and circular sample tubes have been determined as a function of density and shear stress by means of a high shear stress sediment erosion flume at Sandia National Laboratories. This was done to determine if circular cores used in field sampling would provide the same results found using the existing technology of rectangular cores. Two samples were natural, cohesive sediments retrieved from different sites in the Boston Harbor identified as Open Cell and Mid Channel. The other two sediments were medium and coarse grain, non-cohesive quartz sediments. For each sediment type, erosion tests were performed with both rectangular and circular core tubes. For all cores, bulk density was determined as a function of depth and consolidation time. Sediments were eroded to determine erosion rates as a function of density and shear stress for both types of core tubes used. No measurable difference was found between the two core types.
Date: March 1, 2001
Partner: UNT Libraries Government Documents Department


Description: The overall conclusion from this work is that a switch from river sand bed material to limestone at the R.M. Heskett Station would provide substantial benefits to MDU. A switch to limestone would increase the fuel flexibility of the unit, allowing fuels higher in both sodium and sulfur to be burned. The limestone bed can tolerate a much higher buildup of sodium in the bed without agglomeration, allowing either the bed turnover rate to be reduced to half the current sand feed rate for a fuel with equivalent sodium or allow a higher sodium fuel to be burned with limestone feed rates equivalent to the current sand feed rate. Both stack and ambient SO{sub 2} emissions can be controlled. A small improvement in boiler efficiency should be achievable by operating at lower excess oxygen levels at low load. This reduction in oxygen will also lower NO{sub x} emissions, providing a margin of safety for meeting emission standards. No detrimental effects of using limestone at the Heskett Station were uncovered as a result of the test burn. Some specific conclusions from this work include the following: The bed material feed rate can be reduced from the current rate of 5.4% of the coal feed rate (57.4 tons of sand/day) to 2.5% of the coal feed rate (27 tons of limestone/day). This will result in an annual savings of approximately $200,000. (1) SO{sub 2} emissions at the recommended feed rate would be approximately 250 ppm (0.82 lb/MMBtu) using a similar lignite. Based on the cost of the limestones, SO{sub 2} allowances could be generated at a cost of $60/ton SO{sub 2} , leaving a large profit margin for the sale of allowances. The addition of limestone at the same rate currently used for sand feed could generate $455,000 net income if allowances ...
Date: March 1, 1999
Creator: Mann, Michael D. & Henderson, Ann K.
Partner: UNT Libraries Government Documents Department

Mechanical properties of a structural polyurethane foam and the effect of particulate loading

Description: The room temperature mechanical properties of a closed-cell, polyurethane encapsulant foam have been measured as a function of foam density. Tests were performed on both unfilled and filler reinforced specimens. Over the range of densities examined, the modulus of the unloaded foam could be described by a power-law relationship with respect to density. This power-law relationship could be explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model found in the literature. The collapse stress of the foam was also found to exhibit a power-law relationship with respect to density. Additions of an aluminum powder filler increased the modulus relative to the unfilled foam.
Date: April 1, 1998
Creator: Goods, S.H.; Neuschwanger, C.L. & Whinnery, L.L.
Partner: UNT Libraries Government Documents Department

Bonding topologies in diamondlike amorphous-carbon films

Description: The carbon ion energy used during filtered cathodic vacuum arc deposition determines the bonding topologies of amorphous-carbon (a-C) films. Regions of relatively low density occur near the substrate/film and film/surface interfaces and their thicknesses increase with increasing deposition energy. The ion subplantation growth results in mass density gradients in the bulk portion of a-C in the growth direction; density decreases with distance from the substrate for films grown using ion energies < 60 eV and increases for films grown using ion energies > 160 eV. Films grown between these energies are the most diamondlike with relatively uniform bulk density and the highest optical transparencies. Bonding topologies evolve with increasing growth energy consistent with the propagation of subplanted carbon ions inducing a partial transformation of 4-fold to 3-fold coordinated carbon atoms.
Date: January 27, 2000
Partner: UNT Libraries Government Documents Department

Microstructures and mechanical properties of sputtered Cu/Cr multilayers

Description: The microstructures and mechanical properties of Cu/Cr multilayers prepared by sputtering onto {l_brace}100{r_brace} Si substrates at room temperature are presented. The films exhibit columnar grain microstructures with nanoscale grain sizes. The interfaces are planar and abrupt with no intermixing, as expected from the phase diagram. The multilayers tend to adopt a Kurdjumov-Sachs (KS) orientation relationship: {l_brace}110{r_brace}Cr // {l_brace}111{r_brace}Cu, <111>Cr // <110>Cu. The hardness of the multilayered structures, as measured by nanoindentation, increase with decreasing layer thickness for layer thicknesses ranging from 200 nm to 50 nm, whereas for lower thicknesses the hardness of the multilayers is independent of the layer thickness. Dislocation-based models are used to interpret the variation of hardness with layer periodicity. The possible effects of factors such as grain size within the layers, density and composition of films and residual stress in the multilayers are highlighted. Comparisons are made to the mechanical properties of sputtered polycrystalline Cu/Nb multilayers which, like Cu/Cr, exhibit sharp fcc/bcc interfaces with no intermixing and a KS orientation relationship, but have a small shear modulus mismatch.
Date: March 1, 1998
Creator: Misra, A.; Kung, H.; Mitchell, T.E.; Jervis, T.R. & Nastasi, M.
Partner: UNT Libraries Government Documents Department

Ultrahard carbon nanocomposite films

Description: Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.
Date: January 27, 2000
Creator: Siegal, Michael P.; Tallant, David R.; Provencio, Paula P.; Overmyer, Donald L.; Simpson, Regina L. & Martinez-Miranda, L. J.
Partner: UNT Libraries Government Documents Department

Simulation of Granular Compacts in Two Dimensions

Description: Simulations of granular packings in 2-D by throwing disks in a rectangular die are performed. Different size distributions as bimodal, uniform and gaussian are used. Once the array of particles is done, a relaxation process is carried on using a large-amplitude, low-frequency vertical shaking. This relaxation is performed a number N of times. Then, the authors measure the density of the package, contact distribution, coordination number distribution, entropy and also the disks size distribution vs. height. The dependence of all these magnitudes on the number N of shakings used to relax the packing and on the size distribution parameters are explored and discussed.
Date: July 24, 2000
Partner: UNT Libraries Government Documents Department

Excess Foundry Sand Characterization and Experimental Investigation in Controlled Low-Strength Material and Hot-Mixing Asphalt

Description: This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: (1) a statistically sound evaluation of the characterization of foundry sand, (2) a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and (3) the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at N{sub ini}, N{sub des}, and N{sub max}. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.
Date: October 31, 2004
Creator: Tikalsky, Pauul J.
Partner: UNT Libraries Government Documents Department


Description: This research project is aimed at assessing the soil organic carbon (SOC) sequestration potential of reclaimed minesoils (RMS). The experimental sites, owned and maintained by the American Electrical Power, are located in Guernsey, Morgan, Noble, and Muskingum Counties of Ohio. These sites, characterized by age chronosequences, were reclaimed with and without topsoil application and are under continuous grass or forest cover. During this quarter, bulk and core soil samples were collected from all 13 experimental sites for 0-15 cm, 15-30 cm, and 30-50 cm depths. In addition, 54 experimental plots (4 x 4 m) were established at three separate locations on reclaimed minesites to assess the influence of compost application on SOC during project period 2. This report presents the results from two sites reclaimed during 1978. The first site is under grass and the other under forest cover. The soil bulk density ({rho}{sub b}), SOC, total nitrogen (TN) concentrations and stocks were determined for these two sites on a 20 x 20 m grid. The preliminary analysis showed that the {rho}{sub b} ranged from 0.88 Mg m{sup -3} to 1.16 Mg m{sup -3} for 0-15 cm, 0.91 Mg m{sup -3} to 1.32 Mg m{sup -3} for 15-30 cm, and 1.37 Mg m{sup -3} to 1.93 Mg m{sup -3} for 30-50 cm depths in Cumberland tree site, and it's statistical variability was low. The variability in {rho}{sub b} was also low in Wilds grass site and ranged from 0.82 Mg m{sup -3} to 1.18 Mg m{sup -3} for 0-15 cm, 1.04 Mg m{sup -3} to 1.37 Mg m{sup -3} for 15-30 cm, and 1.18 Mg m{sup -3} to 1.83 Mg m{sup -3} for 30-50 cm depths. The {rho}{sub b} showed strong spatial dependence for 0-15 cm depth only in the Cumberland tree site. The SOC concentrations and stocks were highly ...
Date: July 1, 2004
Creator: Shukla, M.K. & Lal, R.
Partner: UNT Libraries Government Documents Department

ERRATA SHEET for ''Lithology and Stratigraphy of Holes Drilled in LANL-Use Areas of the Nevada Test Site''

Description: A conversion error has been discovered in the physical property data table for Emplacement Hole U-19bg (Supplemental Data) presented on Page 89. Data in the column labeled ''Bulk Density (g/cc)'' are actually presented in pounds per cubic foot rather than grams per cubic centimeter. The following table presents the bulk density values for U-19bg in pounds per cubic foot and grams per cubic centimeter.
Date: December 1, 2001
Creator: Prothro, L. B.; S. L. Drellack, Jr. & Allen, B. M.
Partner: UNT Libraries Government Documents Department


Description: The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a lower (effective) porosity. Likewise, discarding the solid portion of the non-participating volume inherently leads to a lower or effective bulk density. In the author's experience, practitioners virtually never adjust bulk density when adopting the effective porosity approach.
Date: February 27, 2012
Creator: Flach, G.
Partner: UNT Libraries Government Documents Department

A parametric pressing study using a plastic-bonded explosive

Description: Pressed plastic-bonded explosives, PBXs, are commonly used by defense and private industry. PBX 9501 is composed of HMX crystals held together with a plastic binder 'softened' with plasticizers. The detonation behavior of any explosive is very dependent upon its density, with the desire to have a uniform, high density throughout the explosive component. A parametric study has been performed pressing PBX 9501 hydrostatically and uniaxially. The effects of several pressing parameters on the bulk density and density profile, as well as mechanical properties, have been measured. The parameters investigated include pressure, temperature, number of cycles, dwell time, rest time, sack thickness, and particle distribution and size. Density distributions within the pressed explosives were also compared.
Date: January 1, 2002
Creator: Hayden, D. J. (David J.); Maez, L. R. (Leland R.); Olinger, B. W. (Barton W.) & Powell, S. J. (Sandra J.)
Partner: UNT Libraries Government Documents Department

Advances in beryllium powder consolidation simulation

Description: A fuzzy logic based multiobjective genetic algorithm (GA) is introduced and the algorithm is used to optimize micromechanical densification modeling parameters for warm isopressed beryllium powder, HIPed copper powder and CIPed/sintered and HIPed tantalum powder. In addition to optimizing the main model parameters using the experimental data points as objective functions, the GA provides a quantitative measure of the sensitivity of the model to each parameter, estimates the mean particle size of the powder, and determines the smoothing factors for the transition between stage 1 and stage 2 densification. While the GA does not provide a sensitivity analysis in the strictest sense, and is highly stochastic in nature, this method is reliable and reproducible in optimizing parameters given any size data set and determining the impact on the model of slight variations in each parameter.
Date: December 1, 1998
Creator: Reardon, B. J.
Partner: UNT Libraries Government Documents Department

The morphology of blends of linear and branched polyethylenes in solid state by SANS

Description: In a previous paper, the authors have shown how small-angle neutron and X-ray scattering (SANS, SAXS) can be used to determine the melt compatibility of different polyolefins, including high-density (HD), low-density (LD), and linear low density (LLD) polyethylene. Such blends have attained widespread commercial applications, though the understanding of the mechanical and melt-flow properties of such blends has hitherto been handicapped by the absence of a consensus concerning the degree of mixing of the components, both in the melt and solid states. Recent SANS data indicate that for HDPE/LDPE blends, the melt is homogeneous for all compositions after proper accounting for H/D isotope effects. In this publication the authors use complementary SANS, DSC, and SAXS to examine the types of morphologies and the different degrees of phase separation which may arise via crystallization effects on cooling from a homogeneous melt.
Date: March 1, 1995
Creator: Wignall, G.D.; Londono, J.D.; Alamo, R.G. & Mandelkern, L.
Partner: UNT Libraries Government Documents Department