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Analysis of Field Compaction Data: Report 2, Littleville Dam, Westfield River, Massachusetts

Description: Summary: This report is a review of the materials, specifications, procedures, equipment, and testing pertinent to construction and compaction control of the earth-fill embankment of Littleville Dam, Westfield River, Mass., constructed by the U. S. Army Engineer Division, New England.
Date: December 1970
Creator: Torrey, Victor H., III
Partner: UNT Libraries Government Documents Department

Laboratory Characterization of Mechanical and Permeability Properties of Dynamically Compacted Crushed Salt

Description: The U. S. Department of Energy plans to dispose of transuranic wastes at the Waste Isolation Pilot Plant (WIPP), a geologic repository located at a depth of about 655 meters. The WIPP underground facility is located in the bedded salt of the Salado Formation. Access to the facility is provided through vertical shafts, which will be sealed after decommissioning to limit the release of hazardous waste from the repository and to limit flow into the facility. Because limited data are available to characterize the properties of dynamically compacted crushed salt, Sandia National Laboratories authorized RE/SPEC to perform additional tests on specimens of dynamically compacted crushed salt. These included shear consolidation creep, permeability, and constant strain-rate triaxial compression tests. A limited number of samples obtained from the large compacted mass were available for use in the testing program. Thus, additional tests were performed on samples that were prepared on a smaller scale device in the RE/SPEC laboratory using a dynamic-compaction procedure based on the full-scale construction technique. The laboratory results were expected to (1) illuminate the phenomenology of crushed-salt deformation behavior and (2) add test results to a small preexisting database for purposes of estimating parameters in a crushed-salt constitutive model. The candidate constitutive model for dynamically compacted crushed salt was refined in parallel with this laboratory testing.
Date: February 1, 1999
Creator: Hansen, F.D.; Mellegard, K.D. & Pfeifle, T.W.
Partner: UNT Libraries Government Documents Department

Theoretical model of granular compaction

Description: Experimental studies show that the density of a vibrated granular material evolves from a low density initial state into a higher density final steady state. The relaxation towards the final density follows an inverse logarithmic law. As the system approaches its final state, a growing number of beads have to be rearranged to enable a local density increase. A free volume argument shows that this number grows as N = {rho}/(1 {minus} {rho}). The time scale associated with such events increases exponentially e{sup {minus}N}, and as a result a logarithmically slow approach to the final state is found {rho} {infinity} {minus}{rho}(t) {approx_equal} 1/lnt.
Date: November 1, 1997
Creator: Ben-Naim, E.; Knight, J.B.; Nowak, E.R.; Jaeger, H.M. & Nagel, S.R.
Partner: UNT Libraries Government Documents Department

Study of Dispersant Agents for Thorium Oxide

Description: S>A preliminary study of dispersing agents for thorium oxide was completed and several of the dispersants have possible uses. Also many of the industrial dispersing agents tested are not usable with thorium oxide due to induced behavior causing balling and caking. The effects of nitric acid concentration were observed to also effect each dispersing agent. (auth)
Date: August 1, 1959
Creator: Bate, L. C. & Leddicotte, G. W.
Partner: UNT Libraries Government Documents Department

Coal log pipeline research at University of Missouri. 3rd quarterly report for 1995, July 1, 1995--September 30, 1995

Description: During this quarter (1/1/95-9/30/95), major progress has been made in the following areas of coal log pipeline research, development and technology transfer: (1) Conceptual design of a test machine based on hydraulic presses to mass-produce 5.4-inch-diameter coal logs for testing in a 6-inch-diameter pipeline has been completed. (2) Conceptual design of a rotary-press machine to produce 1.9-inch-diameter coal logs for testing in a 2-inch-diameter pipeline has also been completed. (3) It has been confirmed through experiments that molds with round-edge exit can make logs as good as those made with tapered exit. (4) Conducted a study to determine the effect of surface condition of mold and lubricants on the quality of coal logs. (5) Completed an evaluation of the effect of fiber (wood pulp) on coal log quality. (6) Prepared an apparatus for testing fast compaction of coal logs -- 2 second per log. (7) Compacted coal logs in a 5.3-inch-diameter mold. (8) Completed a preliminary study to assess vacuum and steam heating systems to enhance coal log production and quality. (9) Changed the small-scale-CLP-demo loop from a once-through system to a recirculating system. (10) Completed revision of CLP economic model and revised the 1993 report.
Date: December 31, 1995
Creator: Liu, H.
Partner: UNT Libraries Government Documents Department

Tank farms compacted low-level waste

Description: This report describes the process of Low-Level Waste (LLW) volume reduction by compaction. Also included is the data used for characterization of LLW destined for compaction. Scaling factors (ratios) are formed based on data contained in this report.
Date: August 1, 1997
Creator: Hetzer, D. C.
Partner: UNT Libraries Government Documents Department

Shock wave structure in heterogeneous reactive media

Description: Continuum mixture theory and mesoscale modeling are applied to describe the behavior of shock-loaded heterogeneous media. One-dimensional simulations of gas-gun experiments demonstrate that the wave features are well described by mixture theory, including reflected wave behavior and conditions where significant reaction is initiated. Detailed wave fields are resolved in numerical simulations of impact on a lattice of discrete explosive {open_quotes}crystals{close_quotes}. It is shown that rapid distortion first occurs at material contact points; the nature of the dispersive fields includes large amplitude fluctuations of stress over several particle pathlengths. Localization of energy causes {open_quotes}hot-spots{close_quotes} due to shock focusing and plastic work as material flows into interstitial regions.
Date: June 1, 1997
Creator: Baer, M.R.
Partner: UNT Libraries Government Documents Department

Ceramic powder compaction

Description: With the objective of developing a predictive model for ceramic powder compaction we have investigated methods for characterizing density gradients in ceramic powder compacts, reviewed and compared existing compaction models, conducted compaction experiments on a spray dried alumina powder, and conducted mechanical tests and compaction experiments on model granular materials. Die filling and particle packing, and the behavior of individual granules play an important role in determining compaction behavior and should be incorporated into realistic compaction models. These results support the use of discrete element modeling techniques and statistical mechanics principals to develop a comprehensive model for compaction, something that should be achievable with computers with parallel processing capabilities.
Date: December 31, 1995
Creator: Glass, S.J.; Ewsuk, K.G. & Mahoney, F.M.
Partner: UNT Libraries Government Documents Department

The influence of crushed rock salt particle gradation on compaction

Description: This paper presents results of laboratory compaction testing to determine the influence of particle size, size gradation and moisture-content on compaction of crushed rock salt. Included is a theoretical analysis of the optimum size gradation. The objective is to evaluate the relative densities that can be achieved with tamping techniques. Initial results indicate that compaction increases with maximum particle size and compaction energy, and varies significantly with article size gradation and water content.
Date: December 31, 1994
Creator: Ran, C. & Daemen, J.J.K.
Partner: UNT Libraries Government Documents Department

Reaction of preshocked explosives

Description: In experiments in which an explosive is subjected to two successive shocks ({approximately}2.5 and {approximately}6.0 GPa), detonation of the explosive is delayed. High compaction resulting from shock compression of an explosive probably results in the removal of voids from the material. To the extent that these voids comprise the hotspots in the material, the shock-compressed explosive might be expected to behave as a homogeneous material, and initiate more like a liquid explosive than like a normal solid PBX. While some evidence is available from the data record to support this idea that detonation develops in a homogeneous manner, predominant aspects of the data indicate heterogeneous development of detonation in the preshocked material.
Date: July 31, 1998
Creator: Mulford, R.N.
Partner: UNT Libraries Government Documents Department

Isostatic pressing development. Quarterly report, October--December, 1971

Description: About 150 process-development pressings were made in prototype tooling. Problems arose which include stress cracking caused by difficult stripping of the part from the mandrel. Pressings made of PBX 9404 presented none of these problems. The primary effort is being directed toward developing a process for LX-09 and LX-04 pressings which at present are the problem areas.
Date: December 31, 1972
Creator: Adams, J.C. & Sheeran, R.E.
Partner: UNT Libraries Government Documents Department

Continuum-Based FEM Modeling of Ceramic Powder Compaction Using a Cap-Plasticity Constitutive Model

Description: Software has been developed and extended to allow finite element (FE) modeling of ceramic powder compaction using a cap-plasticity constitutive model. The underlying, general-purpose FE software can be used to model even the most complex three-dimensional (3D) geometries envisioned. Additionally, specialized software has been developed within this framework to address a general subclass of axisymmetric compacts that are common in industry. The expertise required to build the input deck, run the FE code, and post-process the results for this subclass of compacts is embedded within the specialized software. The user simply responds to a series of prompts, evaluates the quality of the FE mesh that is generated, and analyzes the graphical results that are produced. The specialized software allows users with little or no FE expertise to benefit from the tremendous power and insight that FE analysis can bring to the design cycle. The more general underlying software provides complete flexibility to model more complicated geometries and processes of interest to ceramic component manufacturers but requires significantly more user interaction and expertise.
Date: May 1, 2000
Creator: Arguello, Jose G., Jr.; Fossum, Arlo F.; Zeuch, David H. & Ewsuk, Kevin G.
Partner: UNT Libraries Government Documents Department


Description: The chromatic nonlinearity parameter, {alpha}{sub 1}, has a strong impact on longitudinal dynamics in the vicinity of transition [1,2,3]. Measurements of the synchrotron frequency as a function of radius are used to constrain the value of {alpha}{sub 1}.
Date: June 18, 2001
Partner: UNT Libraries Government Documents Department

Pressing technology. Quarterly report, October--December, 1971

Description: A new process has become available that might be useful for compacting PEX materials. The process is triaxial: it utilizes the familiar isostatic compression vectors to form a billet and for lateral reinforcement while a shear action of higher pressure is included over the billet ends with a mechanical punch. The 20-inch press has been inspected at the site of manufacture and is in transit to Pantex Plant.
Date: December 31, 1972
Creator: Harrell, J.D.
Partner: UNT Libraries Government Documents Department

Compaction Waves in Granular HMX

Description: Piston driven compaction waves in granular HMX are simulated with a two-dimensional continuum mechanics code in which individual grains are resolved. The constitutive properties of the grains are modeled with a hydrostatic pressure and a simple elastic-plastic model for the shear stress. Parameters are chosen to correspond to inert HMX. For a tightly packed random grain distribution (with initial porosity of 19%) we varied the piston velocity to obtain weak partly compacted waves and stronger fully compacted waves. The average stress and wave speed are compatible with the porous Hugoniot locus for uni- axial strain. However, the heterogeneities give rise to stress concentrations, which lead to localized plastic flow. For weak waves, plastic deformation is the dominant dissipative mechanism and leads to dispersed waves that spread out in time. In addition to dispersion, the granular heterogeneities give rise to subgrain spatial variation in the thermodynamic variables. The peaks in the temperature fluctuations, known as hot spots, are in the range such that they are the critical factor for initiation sensitivity.
Date: January 1, 1999
Creator: Kober, E. & Menikoff, R.
Partner: UNT Libraries Government Documents Department

Large-scale dynamic compaction of natural salt

Description: A large-scale dynamic compaction demonstration of natural salt was successfully completed. About 40 m{sup 3} of salt were compacted in three, 2-m lifts by dropping a 9,000-kg weight from a height of 15 m in a systematic pattern to achieve desired compaction energy. To enhance compaction, 1 wt% water was added to the relatively dry mine-run salt. The average compacted mass fractional density was 0.90 of natural intact salt, and in situ nitrogen permeabilities averaged 9X10{sup -14}m{sup 2}. This established viability of dynamic compacting for placing salt shaft seal components. The demonstration also provided compacted salt parameters needed for shaft seal system design and performance assessments of the Waste Isolation Pilot Plant.
Date: May 1, 1996
Creator: Hansen, F.D. & Ahrens, E.H.
Partner: UNT Libraries Government Documents Department

Coal log pipeline research at University of Missouri. Fourth quarterly report for 1995, October 1, 1995--December 30, 1995

Description: The purpose of this project is to design and develop fast and efficient machines for manufacturing high quality coal logs. During the last three months, efforts were focused on the revision and improvement of the design of the 300-ton hydraulic press machine for coal log production. The conceptual design of the machine has been sent to Automated Resources, Inc. for review. Experiments were conducted on threshold binder (orimulsion) concentration. It showed that for binder concentrations below 1%, the initial weight loss of coal logs (due to chipping of corner) is unaffected by the binder concentration unless the binder concentration is 1% or more. For binder levels above 0.25%, more binder causes less coal log wear after long time or or large number of cycles of circulation through pipe. After 250 cycles in the pipe, binderless coal logs suffer approximately twice the wear of the logs with 1% binder.
Date: December 31, 1995
Creator: Liu, H.
Partner: UNT Libraries Government Documents Department

Low temperature fabrication from nano-size ceramic powders

Description: The objective of the compaction process is to produce a dense green-state compact from a nanosize powder that subsequently can be sintered at high temperatures to form a dense ceramic piece. High density in the green-state after pressing is of primary importance for achieving high densities after sintering. Investigation of the compaction behavior of ceramic powders, therefore, is an important part of characterization of raw ceramic powders and evaluation of their compaction behavior, analysis of interaction between particles, and the study of microstructure of green body (unsintered) during pressure-forming processes. The compaction of nanosize ceramic particles into high density green bodies is very difficult. For the nanosize materials used in this study (amorphous Si{sub 3}N{sub 4} and {gamma} Al{sub 2}O{sub 3}), there is no evidence by TEM of partial sintering after synthesis. Nevertheless, strong aggregation forces, such as the van der Waals surface forces of attraction, exist and result in moderate precursor particle agglomeration. More importantly, these attractive surface forces, which increase in magnitude with decreasing particle size, inhibit interparticle sliding necessary for particle rearrangement to denser bodies during subsequent compaction. Attempts to produce high density green body compacts of nanosize particles, therefore, generally have been focused on overcoming these surface forces of attraction by using either dispersive fluids or high pressures with or without lubricating liquids. In the present work, the use of high pressure has been employed as a means of compacting nanosize powders to relatively high green densities.
Date: June 1, 1995
Creator: Gonzalez, E.J.; Piermarini, G.J. & Hockey, B.
Partner: UNT Libraries Government Documents Department

Dynamic compaction of granular materials in a tube with wall friction, applied to deflagration-to-detonation transition

Description: A theoretical problem is considered in which a granular material is pushed through a tube of arbitrary cross-section by a constant velocity piston against the resistance of compaction work and wall friction. The crushing of the material is dictated by a simple yet physically reasonable compaction law. By considering two special cases - the limit of vanishing friction and the quasistatic limit - we identify the two basic compaction wave structures. We then consider the general case in which the two waves interact. Estimates suggest that for typical deflagration-to-detonation tests explosive at the wall melts on time scales short compared to the experiment.
Date: September 1, 1995
Creator: Hill, L.G. & Kapila, A.K.
Partner: UNT Libraries Government Documents Department

Applied mechanics modeling of granulated ceramic powder compaction

Description: In ceramic manufacturing processes such as dry-pressing, correlations between applied compacting pressure and resultant powder compact density are essential for defining reliable process conditions for ceramic components. Pressure-density diagrams have been developed as a tool for both process control and for understanding the compaction behavior of different powders. These types of diagrams, however, pertain only to the averag@ properties of a powder compact and do not address a significant issue in powder compaction processes: the formation of density gradients within the compact. Continuum-based mechanics models of varying complexity have addressed the influence of frictional forces acting at the powder-die wall interface which dissipate the applied pressure throughout the compact. Resulting pressure distribution models are then typically coupled with empirical functions relating pressure and density to obtain a green density distribution in the compact. All of these models predict similar trends; however, none predict the distribution with sufficient accuracy to be considered as a design tool for industrial applications.
Date: August 1, 1995
Creator: Mahoney, F.M. & Readey, M.J.
Partner: UNT Libraries Government Documents Department

Ceramic granule strength variability and compaction behavior

Description: Diametral compression strength distributions and the compaction behavior and of irregular shape 150--200 {mu}m ceramic granules and uniform-size 210 {mu}m glass spheres were measured to determine how granule strength variability relates to compaction behavior of granular assemblies. High variability in strength, represented by low Weibull modulus values (m<3) was observed for ceramic granules having a distribution of sizes and shapes, and for uniform-size glass spheres. Compaction pressure data were also analyzed using a Weibull distribution function, and the results were very similar to those obtained from the diametral compression strength tests for the same material. This similarity suggests that it may be possible to model granule compaction using a weakest link theory, whereby an assemblage of granules is viewed as the links of a chain, and failure of the weakest granule (i.e., the weakest link) leads to rearrangement and compaction. Additionally, with the use of Weibull statistics, it appears to be possible to infer the variability in strength of individual granules from a simple pressure compaction test, circumventing the tedious task of testing individual granules.
Date: August 1, 1995
Creator: Glass, S.J.; Ewsuk, K.G. & Readey, M.J.
Partner: UNT Libraries Government Documents Department

The Influence of Lubrication on the Compactability of Magnesium-Green Salt Blends for Bomb Reduction

Description: Lubrication of die surfaces with mineral oil or Dag 217 during final compacting of UF/sub 4/--Mg blends prevented seizing. Mineral oil application after every third press allowed 18 compacts before seizing became severe. Similar application of Dag 217 allowed 78 compacts. Mixing 0.33 wt.% Ceremul "C" with the powder allowed 40 compacts. Punch clearance had little effect on seizing. (T.R.H.)
Date: June 18, 1957
Creator: Paprocki, S. J.; Carlson, R. J. & Smith, E. G., Jr.
Partner: UNT Libraries Government Documents Department