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Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly report No. 9, September 1, 1988--November 30, 1988

Description: A real-time laser light-reflectivity technique is being used to study simultaneous thermophoretic and inertial influences on the deposition behavior of MgO particles produced via ultrasonic nebulization (submicrometer range). The deposition surface (a concave platinum ribbon) is exposed to a high velocity/temperature jet of alkali sulfate-free combustion products exiting from a seeded (C3{sub 3}H{sub 8}/air) microcombustor (110 cm{sup 3}). The reflectivity data were calibrated against deposition rates obtained from SEM pictures of the target, and were normalized with the nominal particle feed rate, in order to obtain the mass transfer Stanton number, St{sub m}, trends depicted in Figure 1. For the submicron (ca. 0.7{mu}m) particles inertial effects appear to set in at Stokes (Stk) numbers of O(10{sup {minus}2}) (an order of magnitude lower than the ones needed for ``pure`` inertial impaction), affecting significantly the dominant thermophoretic deposition mechanism. A first order (in Stk) theoretical analysis of the problem in which particle inertia is treated as equivalent to ``pressure diffusion,`` cannot explain the observed dependence of the deposition rate on Stk. We are presently formulating a Lagrangian approach, valid for all values of Stk, in order to interpret these data. In addition, a Single Particle Counter (SPC) and Transit Time Velocimeter (TTV), are being developed, to allow more precise measurements of particle feed rates and velocities.
Date: December 1, 1988
Creator: Rosner, D. E.
Partner: UNT Libraries Government Documents Department

The development of a selective ruthenium catalyst. Technical progress report, October 1, 1987--December 31, 1987

Description: A micelle technique was developed for preparing supported catalysts with different size ruthenium particles. Ruthenium was stabilized on the support, light ends make was minimized and activity was maximized by adjusting the ruthenium particle size and the metal-support interaction. The most promising catalysts consisted of 10--15 nm ruthenium particles on an alumina-titania support and 4--6 nm ruthenium particles on an alumina support. Stability improvement was determined to be the major catalyst developmental need. Work during the next quarter will focus on the development of a stable ruthenium catalyst.
Date: December 31, 1987
Creator: Abrevaya, H.
Partner: UNT Libraries Government Documents Department

Optical properties of fly ash. Quarterly report, 1 Apr 1988--30 June 1988

Description: This task is planned to provide the basic optical properties data in a comprehensive and conveniently usable form. The optical constants (i.e., the components of the complex refractive index m = n - ik) of samples of synthetic slags of controlled compositions will be measured using established techniques involving transmission and surface reflectance methods. The wavelength range will extend from the visible to 12 {mu}m and the temperature range will extend to 2000K. Initially, the optical constants of the basic calcium-aluminosilicate host glass will be determined for the composition range defined by Task 1. Subsequently, by adding infrared-active mineral oxide constituents in controlled amounts, one at a time, the modifications to m({Lambda}, T) produced by such constituents will be quantitatively determined. The particular constituents (and their range of mass fractions) to be examined will be determined by those disclosed by Task 1, taking account of knowledge of the optical activity at relevant wavelengths of such additions from the literature of glass technology. Specific constituents to be examined will include Fe{sub 2}O{sub 3}, taking especial account of its valence state (Fe{sup 2+}/Fe{sup 3+} ratio), and of TiO{sub 2}. The contribution of the OH radical to the optical properties will be evaluated and quantified if significant. The experimental data on m({Lambda},T) as a function of composition, over the range relevant to coal ashes, will be reduced to generate simple correlation formulae. The latter will constitute the data base necessary to calculate the radiative properties of bulk slags and ash dispersions required for understanding and computing radiative transfer in coal combustion systems.
Date: July 1, 1988
Creator: Self, S. A.
Partner: UNT Libraries Government Documents Department

RESRAD. Site-Specific Residual Radioactivity

Description: RESRAD is designed to derive site-specific guidelines for allowable residual concentrations of radionuclides in soil. A guideline is defined as a radionuclide concentration or a level of radiation or radioactivity that is acceptable if a site is to be used without radiological restrictions. Guidelines are expressed as (1) concentrations of residual radionuclides in soil, (2) concentrations of airborne radon decay products, (3) levels of external gamma radiation, (4) levels of radioactivity from surface contamination, and (5) concentrations of residual radionuclides in air and water. Soil is defined as unconsolidated earth material, including rubble and debris that may be present. The controlling principles of all guidelines are (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and averaged over a 50 year period - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable. All significant exposure pathways for the critical population group are considered in deriving soil guidelines. These pathways include direct exposure to external radiation from the contaminated soil material; internal radiation from inhalation of airborne radionuclides; and internal radiation from ingestion of plant foods grown in the contaminated soil, meat and milk from livestock fed with contaminated fodder and water, drinking water from a contaminated well, and fish from a contaminated pond.
Date: June 1, 1989
Creator: Yu, C.
Partner: UNT Libraries Government Documents Department

Optical properties of flyash. Quarterly report, 1 April--30 June 1989

Description: The purpose of this task is to validate the whole approach adopted in this program. Specifically, this bench-scale experiment is intended to compare the measured optical/radiative properties of a dispersion of well characterized ash with those calculated on the basis of the known size/composition distribution using the correlation formulae relating the composition and complex refractive index resulting from measurements on bulk samples of synthetic slag. Considerable thought has been given to the various possible approaches to satisfying the objectives of this task. Several experiments were done to guide our design of an apparatus for measuring the scattering and absorption properties of dispersions of flyash. As a result of these experiments, and from extensive prior experience in connection with research on electrostatic precipitation, it has been determined that there is no satisfactory way to satisfy the aims of this task using a gaseous dispersion of flyash because it is not possible to adequately disperse and deagglomerate flyash into a gas stream. Unless the ash is adequately dispersed, as it exists in the radiant boiler of a pulverized coal-fired combustion system, one cannot expect calculations, based on Mie calculations for a dispersion of spheres to properly agree with laboratory measurements. For these reasons, our design efforts are based on making measurements on a dispersion of flyash in liquid, for which our experience shows we can obtain stable, well-deagglomerated dispersions of ash. Because there is not single liquid which is adequately transparent over the wavelength range 1--12 {mu}m, we plan to use a combination of three liquids, C Cl{sub 4}, C S{sub 2} and bromoform to cover the full range. Windows of BaF{sub 2} will be used to contain the liquid suspension in an absorption/scattering cell.
Date: July 1, 1989
Creator: Self, S. A.
Partner: UNT Libraries Government Documents Department

Advanced Vortexing Combustor (VC) for space/water heating applications (proof-of-concept model development). Technical progress report No. 1

Description: The Naval Civil Engineering Laboratory is developing a proof-of-concept Vortexing Combustor (VC) with 2--4 MMBtu/hr firing capacity to bum both coal-water fuel and ultrafine coal for boiler applications. Thermodynamic analysis was made to trade off design features of the combustor. Results indicated that for best thermal efficiency, consistent with the low temperature combustion requirements, a sub-adiabatic VC arrangement should be selected. In order to minimize the risk of uncertainties, a three-step approach was chosen by which two small size models (0.15 and 0.6 MMBtu/hr) will be designed, built, and tested. The full-scale, proof-of-concept model will then be designed based on the results of tests using the small-scale models. Extensive testing of the full-scale model will be conducted to prove the concept. All combustors will be designed based on the use of one type of coal-water fuel. Ultrafine coal will be tested and regarded as a variance. The design and construction of the 0.15 MMBtu/hr model has been completed and it is being assembled for exploratory testing of the VC concept. Several major pieces of equipment, purchased with NCEL funds as a part of the cost sharing effort have arrived. The overall project has been progressing well and is on schedule. Hot testing of the 0.15 MMBtu/hr model will take place in the March--June time frame.
Date: March 1, 1988
Creator: Fu, T. T.
Partner: UNT Libraries Government Documents Department

A parallel multigrid method for data-driven multiprocessor systems

Description: The multigrid algorithm (MG) is recognized as an efficient and rapidly converging method to solve a wide family of partial differential equations (PDE). When this method is implemented on a multiprocessor system, its major drawback is the low utilization of processors. Due to the sequentiality of the standard algorithm, the fine grid levels cannot start relaxation until the coarse grid levels complete their own relaxation. Indeed, of all processors active on the fine two dimensional grid level only one fourth will be active at the coarse grid level, leaving full 75% idle. In this paper, a novel parallel V-cycle multigrid (PVM) algorithm is proposed to cure the idle processors` problem. Highly programmable systems such as data-flow architectures are then applied to support this new algorithm. The experiments based on the proposed architecture show that the convergence rate of the new algorithm is about twice faster than that of the standard method and twice as efficient system utilization is achieved.
Date: December 31, 1989
Creator: Lin, C. H.; Gaudiot, J. L. & Proskurowski, W.
Partner: UNT Libraries Government Documents Department

Engineering evaluation of ruptured strainer in Building 309

Description: This report deals with the consequences of the ruptured steam strainer and is divided into two sections. Section 1 evaluates the engineering aspects of the ruptured steam strainer, investigates the events that culminated in the damage and considers factors that may have contributed to the incident. Recommendations are presented to upgrade the system in Building 309 by incorporating hardware changes and proposes a change in operating procedures. Section 2 utilizes the findings presented in Section 1 as a basis for conducting a review on the remainder of the 300 Area steam system, in order to identify similar problem areas. Corrective action recommendations to reduce the risk of repeating component ruptures from water hammer conditions were developed out of the survey and the associated review.
Date: October 1, 1982
Creator: Papenfuss, J. N.
Partner: UNT Libraries Government Documents Department

Active layer hydrology for Imnavait Creek, Toolik, Alaska. Annual progress report, July 1984--January 1986

Description: In the annual hydrologic cycle, snowmelt is the most significant event at Imnavait Creek located near Toolik Lake, Alaska. Precipitation that has accumulated for more than 6 months on the surface melts in a relatively short period of 7 to 10 days once sustained melting occurs. During the ablation period, runoff dominates the hydrologic cycle. Some meltwater goes to rewetting the organic soils in the active layer. The remainder is lost primarily because of evaporation, since transpiration is not a very active process at this time. Following the snowmelt period, evapotranspiration becomes the dominate process, with base flow contributing the other watershed losses. It is important to note that the water initally lost by evapotranspiration entered the organic layer during melt. This water from the snowpack ensures that each year the various plant communities will have sufficient water to start a new summer of growth.
Date: December 31, 1986
Creator: Kane, D. L.
Partner: UNT Libraries Government Documents Department

SP-100, a project manager`s view. Technical information report

Description: Born to meet the special needs of America`s space effort, the SP-100 Program testifies to the cooperation among government agencies. The Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the Defense Advanced Research Projects Agency (DARPA) are working together to produce a 100-kW power system for use in outer space. At this point in the effort, it is appropriate to review: The approach to meet program goals; the status of activities of the Project Office, managed by the Jet Propulsion Laboratory (JPL); and, because this is a meeting on materials, answers beings developed by the Project Office to vital questions on refractory alloy technology.
Date: December 1, 1983
Creator: Truscello, V. C.
Partner: UNT Libraries Government Documents Department

Top-level regulatory criteria for the standard MHTGR

Description: The Top-Level Regulatory Criteria (TLRC) are defined as the standards for judging nuclear power plant licensability related to control of radionuclides that directly specify acceptable quantified limits on radionuclide releases for the public health and safety and the environment. The purpose of the TLRCis to establish a consistent and unambiguous quantitative basis for judging the acceptability of potential radionuclide releases such that protection to the public health and safety and the environment is maintained. In the Modular High Temperature Gas-Cooled Reactor (MHTGR) program, these criteria establish numerical values against which potential releases of radioactive materials during anticipated and off-normal events are judged. They are proposed for concurrence by the Nuclear Regulatory Commission (NRC) with their completeness and acceptability. The approach taken is to select from regulations and current guidance a set of quantifiable consequence and risk criteria of general applicability to nuclear power plants. They encompass normal plant operation and a broad spectrum of off-normal events.
Date: September 1, 1989
Creator: Lewis, J. H.
Partner: UNT Libraries Government Documents Department

Sequential Purification and Crystal Growth for the Production of Low Cost Silicon Substrates

Description: The objective of this program is to identify and develop low cost precessing for fabricating large grain size polycrystalline silicon substrates. Metallurgical grade silicon (MG-Si) is chosen as the starting material for sequential purification and crystal growth. Several purification techniques have been studied. They include (1) acid leaching with HCl, (2) physical separation of insoluble impurities, (3) reactive gas treatment of molten silicon, and (4) slagging using a mixed-oxide slag. In this quarterly period purification by vaccum treatment and by impurity redistribution using ingot pulling has been studied. Procedures and results are reported.
Date: August 1, 1980
Creator: Liaw, M.; D&#x27 & Aragona, F. S.
Partner: UNT Libraries Government Documents Department

Scale-up Synthesis of Diallyl Phthalate Prepolymer

Description: This project was initiated to develop processes for the synthesis of diallyl phthalate (DAP) prepolymer in the Bendix Chemical Polymer Facility. Thus far, five scale-up reactions have been carried out in a 100-gallon reactor and fourteen have been conducted in the 15-gallon resin kettle. The synthesis of diallyl isophthalate prepolymer (DAIPP) was also investigated; eight scale-up reactions of this prepolymer have been carried out. Aging studies on DAIPP were also conducted.
Date: October 1, 1984
Creator: Carey, D. A.
Partner: UNT Libraries Government Documents Department

Automatic monitoring of valve status

Description: Authors propose establishing the relationship between valve leaking and thermal gradient to allow detection of valve leakage by observing the piping system`s temperature profile and using an expert system to infer the valve condition. They describe their work toward this and their January 1988 report thereon. The authors also suggest designing modem power plants to accommodate a remotely controlled or autonomous vehicle which would carry a device for thermal-gradient leak detection to examine valves in situ.
Date: June 1, 1989
Creator: Prinz, F. B. & Chern, J. H.
Partner: UNT Libraries Government Documents Department