Porous networks derived from synthetic polymer-clay complexes (open access)

Porous networks derived from synthetic polymer-clay complexes

Synthetic hectorites were hydrothermally crystallized with direct incorporation of a cationic polymer poly(dimethyl diallyl ammonium chloride) (PDDA), and two neutral cellulosic polymers hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC). Synthetic PDDA-hectorite displays the lowest d-spacing at 15.8 {Angstrom} along with less polymer incorporation (7.8 wt % organic) than the neutral polymers (18--22 wt % organic). Thermal analysis and small angle neutron scattering were used to further examine the polymer-clay systems. Clay platelets of the largest size and best stacking order occur when cationic PDDA polymer is used. PDDA also enhances these properties over the crystallites prepared for a control mineral, where no polymer is used. HEC acts to aggregate the silica, leaving less to react to form clay. The clay platelets which result from HEC are small, not stacked to a large degree, and oriented randomly. Neutral HPMC acts more like cationic PDDA in that larger clay platelets are allowed to form. The extended microstructure of the clay network remains undisturbed after polymer is removed by calcination. When no polymer is used, the synthetic hectorite has a N{sub 2} BET surface area of 200 M{sup 2}/gm, even after calcination. This increases by 20--50% for the synthetic polymer-hectorites after the polymer …
Date: May 12, 1995
Creator: Carrado, K. A.; Thiyagarajan, P. & Elder, D. L.
Object Type: Article
System: The UNT Digital Library
Defining the Glass Composition Limits for SRS Contaminated Soils (open access)

Defining the Glass Composition Limits for SRS Contaminated Soils

Contaminated soil resulting from the excavation, repair, and decommissioning of facilities located at the Savannah River Site (SRS) is currently being disposed of by shallow land burial or is being stored when considered only hazardous. Vitrification of this waste is being investigated, since it will bind the hazardous and radioactive species in a stable and durable glass matrix, which will reduce the risk of ground water contamination. However, the composition limits for producing durable glass have to be determined before the technology can be applied. Glass compositions, consisting of SRS soil and glass forming additives, were tested on a crucible-scale in three ternary phase systems. Nine different glass compositions were produced, with waste loadings ranging from 43 to 58 weight percent. These were characterized using varoius chemical methods and tested for durability in both alkaline and acidic environments. All nine performed well in alkaline environments, but only three met the strictest criteria for the acidic environment tests. Although the glasses did not meet all of the limits for the acidic tests, the test was performed on very conservative size samples, so the results were also conservative. Therefore, enough evidence was found to provide proof that SRS soil can be vitrified …
Date: May 12, 1995
Creator: Cicero, C.A.; Bickford, D.F. & Crews, W.O.
Object Type: Report
System: The UNT Digital Library
Engineering report of plasma vitrification of Hanford tank wastes (open access)

Engineering report of plasma vitrification of Hanford tank wastes

This document provides an analysis of vendor-derived testing and technology applicability to full scale glass production from Hanford tank wastes using plasma vitrification. The subject vendor testing and concept was applied in support of the Hanford LLW Vitrification Program, Tank Waste Remediation System.
Date: May 12, 1995
Creator: Hendrickson, D.W.
Object Type: Report
System: The UNT Digital Library
Advanced conceptual design report: T Plant secondary containment and leak detection upgrades. Project W-259 (open access)

Advanced conceptual design report: T Plant secondary containment and leak detection upgrades. Project W-259

The T Plant facilities in the 200-West Area of the Hanford site were constructed in the early 1940s to produce nuclear materials in support of national defense activities. T Plant includes the 271-T facility, the 221-T facility, and several support facilities (eg, 2706-T), utilities, and tanks/piping systems. T Plant has been recommended as the primary interim decontamination facility for the Hanford site. Project W-259 will provide capital upgrades to the T Plant facilities to comply with Federal and State of Washington environmental regulations for secondary containment and leak detection. This document provides an advanced conceptual design concept that complies with functional requirements for the T Plant Secondary Containment and Leak Detection upgrades.
Date: May 12, 1995
Creator: Hookfin, J. D.
Object Type: Report
System: The UNT Digital Library
Modeling the dynamic crush of impact mitigating materials (open access)

Modeling the dynamic crush of impact mitigating materials

Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence the dynamic mechanical behavior of crushable materials. One issue we addressed was that no single existing model would account for the entire gambit of constitutive features which are important for crushable materials. Thus, we describe the implementation and use of an additional material model which attempts to provide a more comprehensive model of the mechanics of crushable material behavior. This model combines features of the pre-existing DYNA models and incorporates some new features as well in an invariant large-strain formulation. In addition to examining the behavior of a unit cell in uniaxial compression, two cases were chosen to evaluate the capabilities and accuracy of the various material models in DYNA. In the first case, a model for foam filled box beams was developed and compared to …
Date: May 12, 1995
Creator: Logan, R.W. & McMichael, L.D.
Object Type: Article
System: The UNT Digital Library
Coal-water slurry fuel combustion testing in an oil-fired industrial boiler. Semiannual technical progress report, August 15, 1994--February 15, 1995 (open access)

Coal-water slurry fuel combustion testing in an oil-fired industrial boiler. Semiannual technical progress report, August 15, 1994--February 15, 1995

The Pennsylvania State University is conducting a coal-water slurry fuel (CWSF) program for the United States Department of Energy (DOE) and the Commonwealth of Pennsylvania with the objective of determining the viability of firing CWSF in an industrial boiler designed for heavy fuel oil. Penn State and DOE have entered into a cooperative agreement to determine if CWSFs prepared from cleaned coal (containing approximately 3.5 wt.% ash and 0.9 wt.% sulfur) can be burned effectively in a heavy fuel oil-designed industrial boiler without adverse impact on boiler rating, maintainability, reliability, and availability. The project will also provide information to help in the design of new systems specifically configured to fire these clean coal-based fuels. The project consists of four phases: (1) design, permitting, and test planning, (2) construction and start up, (3) demonstration and evaluation (1,000-hour demonstration), and (4) expanded demonstration and evaluation (installing a CWSF preparation circuit, conducting an additional 1,000 hours of testing, and installing an advanced flue gas treatment system). The boiler testing and evaluation will determine if the CWSF combustion characteristics, heat release rate, fouling and stagging behavior, corrosion and erosion tendencies, and fuel transport, storage, and handling characteristics can be accommodated in a boiler system …
Date: May 12, 1995
Creator: Miller, Bruce G. & Scaroni, Alan W.
Object Type: Report
System: The UNT Digital Library
Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows (open access)

Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

The sectional high-frequency internally-cooled window, as proposed by General Atomics, has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses are for the window, under vacuum at one MW and includes variations in the shapes of the cooling fins, the surface treatment of the window elements themselves, the cooling fin tip treatment, the window pitch angle, and the waveguide effects. One advantage of the distributed cooled window is it`s extensibility to higher power levels. Results in the modeling efforts are presented showing the EM field concentrations (which then will feed into the thermal analysis), the energy scattering/reflection, the transmitted launch angle variation as a function of physical geometry, and the spatial energy distribution and loss as a function of time and position.
Date: May 12, 1995
Creator: Nelson, S. D.; Reitter, T. & Caplan, M.
Object Type: Article
System: The UNT Digital Library
Design Evaluation Process for Existing Waste Removal Design Documents (open access)

Design Evaluation Process for Existing Waste Removal Design Documents

This document provides guidelines for implementing Engineering`s responsibility relating to evaluating the adequacy of existing project design outputs. At this time, there exists design documents that were prepared and approved for modifications to operating facilities, that may or may not have been constructed, but have never been turned over to the Operating Facility Management. The process described herein describes the methodology to perform an evaluation of these existing designs and document the findings. The key elements in this process are (1) to evaluate the existing design for general adequacy of the design, (2) to evaluate the existing design due to changes subsequent to the issuance of the documents (i.e. lessons learned, codes or standards change, changes to input documents, ect.), and (3) to verify the existence of critical supporting documentation in the areas of personnel safety, facility safety or environmental compliance.
Date: May 12, 1995
Creator: Smith, P.D.
Object Type: Report
System: The UNT Digital Library
CONTAIN code analyses of direct containment heating (DCH) experiments: Model assessment and phenomenological interpretation (open access)

CONTAIN code analyses of direct containment heating (DCH) experiments: Model assessment and phenomenological interpretation

Models for direct containment heating (DCH) in the CONTAIN code for severe accident analysis have been reviewed and a standard input prescription for their use has been defined. The code has been exercised against a large subset of the available DCH data base. Generally good agreement with the experimental results for containment pressurization ({Delta}P) and hydrogen generation has been obtained. Extensive sensitivity studies have been performed which permit assessment of many of the strengths and weaknesses of specific model features. These include models for debris transport and trapping, DCH heat transfer and chemistry, atmosphere-structure heat transfer, interactions between nonairborne debris and blowdown steam, potential effects of debris-water interactions, and hydrogen combustion under DCH conditions. Containment compartmentalization is an important DCH mitigator in the calculations, in agreement with experimental results. The CONTAIN model includes partially parametric treatments for some processes that are not well understood. The importance of the associated uncertainties depends upon the details of the DCH scenario being analyzed. Recommended sensitivity studies are summarized that allow the user to obtain a reasonable estimate of the uncertainties in the calculated results.
Date: May 12, 1995
Creator: Williams, D. C.; Griffith, R. O.; Tadios, E. L. & Washington, K. E.
Object Type: Article
System: The UNT Digital Library
Measurement of wavefront structure from large aperture optical components by phase shifting interferometry (open access)

Measurement of wavefront structure from large aperture optical components by phase shifting interferometry

This paper discusses the results of high spatial resolution measurement of the transmitted or reflected wavefront of optical components using phase shifting interferometry with a wavelength of 6328 {angstrom}. The optical components studied range in size from approximately 50 mm {times} 100 mm to 400 mm {times} 750 mm. Wavefront data, in the form of 3-D phase maps, have been obtained for three regimes of scale length: ``micro roughness``, ``mid-spatial scale``, and ``optical figure/curvature.`` Repetitive wavefront structure has been observed with scale lengths from 10 mm to 100 mm. The amplitude of this structure is typically {lambda}/100 to {lambda}/20. Previously unobserved structure has been detected in optical materials and on the surfaces of components. We are using this data to assist in optimizing laser system design, to qualify optical components and fabrication processes under study in our component development program.
Date: May 12, 1995
Creator: Wolfe, C. R.; Lawson, J. K.; Kellam, M.; Maney, R. T. & Demiris, A.
Object Type: Article
System: The UNT Digital Library