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Evaluation of process for sludge particle size reduction

Description: This document evaluates the available technology for K Basin sludge particle size. The results can be used to demonstrate the sensitivity or lack thereof, of K Basin sludge to available reduction processes and TWRS proposed particle acceptance criteria.
Date: March 18, 1997
Creator: Precechtel, D.R. & Packer, M.J., Fluor Daniel Hanford
Partner: UNT Libraries Government Documents Department

Method for determining aerosol particle size, device for determining aerosol particle size

Description: A method for determining the mass median diameter D of particles contained in a fluid is provided wherein the data of the mass of a pre-exposed and then a post-exposed filter is mathematically combined with data concerning the pressure differential across the same filter before and then after exposure to a particle-laden stream. A device for measuring particle size is also provided wherein the device utilizes the above-method for mathematically combining the easily quantifiable data.
Date: December 1, 1997
Creator: Novick, Vincent J.
Partner: UNT Libraries Government Documents Department

Sediment studies at Bikini Atoll part 1. distribution of fine and coarse components in surface sediments

Description: In 1979, 21 years after the moratorium on nuclear testing in the Marshall Islands, surface sediment samples (to depths of 2 and 4 cm) were collected from 87 locations over the floor of Bikini lagoon. The main purpose for the collections was to map the distribution of long- lived man-made radionuclides associated with the bottom material. In addition the samples were processed to estimate the fraction of fine and coarse components to show what modifications occurred since the sediment composition was first described in samples collected before testing in 1946. In this report a comparison is made of the amount and distribution of fine material associated with the lagoon surface sediment before and after the testing of nuclear devices. Nuclear testing produced more finely divided material in-the surface sediment layer over large areas of the lagoon and especially in regions of the lagoon and reef adjacent to test sites. Five cratering events at Bikini Atoll generated sufficient material to account for the inventory of new fine material found over the bottom surface of the lagoon. Although the fraction of fine material in the bottom sediments was altered by the nuclear events, the combined processes of formation, transport and deposition were not sufficiently dynamic to alter the geographical features of the major sedimentary components over most of the lagoon floor.
Date: January 1, 1997
Creator: Noshkin, V. E.; Eagle, R.J. & Robison, W.L.
Partner: UNT Libraries Government Documents Department

Nanodiamonds: Their Structure and Optical Properties

Description: Nanometer sized diamond is a constituent of diverse systems ranging from interstellar dusts and meteorites [1] to carbonaceous residues of detonations [2] and diamond-like films [3-5]. Many of the properties of bulk diamond have been well understood for decades, those of nanodiamond are mostly unexplored. We present a combined theoretical and experimental study showing that diamond has unique properties not only as a bulk material but also at the nanoscale, where size reduction and surface reconstruction effects are fundamentally different from those found, e.g. in Si and Ge.
Date: May 14, 2002
Creator: Raty, J.-Y.; van Buuren, T. & Galli, G.
Partner: UNT Libraries Government Documents Department

Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles

Description: The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.
Date: October 1, 2008
Creator: Gilbert, Benjamin
Partner: UNT Libraries Government Documents Department

Size Effect of Ruthenium Nanoparticles in Catalytic Carbon Monoxide Oxidation

Description: Carbon monoxide oxidation over ruthenium catalysts has shown an unusual catalytic behavior. Here we report a particle size effect on CO oxidation over Ru nanoparticle (NP) catalysts. Uniform Ru NPs with a tunable particle size from 2 to 6 nm were synthesized by a polyol reduction of Ru(acac){sub 3} precursor in the presence of poly(vinylpyrrolidone) stabilizer. The measurement of catalytic activity of CO oxidation over two-dimensional Ru NPs arrays under oxidizing reaction conditions (40 Torr CO and 100 Torr O{sub 2}) showed an activity dependence on the Ru NP size. The CO oxidation activity increases with NP size, and the 6 nm Ru NP catalyst shows 8-fold higher activity than the 2 nm catalysts. The results gained from this study will provide the scientific basis for future design of Ru-based oxidation catalysts.
Date: April 4, 2010
Creator: Joo, Sang Hoon; Park, Jeong Y.; Renzas, J. Russell; Butcher, Derek R.; Huang, Wenyu & Somorjai, Gabor A.
Partner: UNT Libraries Government Documents Department

Disorder and size effects on Kondo interactions and magneticcorrelations in CePt2 nanoscrystals

Description: The evolution of the Kondo effect and magnetic correlations with size reduction in CePt{sub 2} nanoparticles (3.1-26 nm) is studied by analysis of the temperature-dependent specific heat and magnetic susceptibility. The antiferromagnetic correlations diminish with size reduction. The Kondo effect predominates at small particle size with trivalent, small Kondo temperature (T{sub K}) magnetic regions coexisting with strongly mixed valent, large T{sub K} nonmagnetic regions. We discuss the role of structural disorder, background density of states and the electronic quantum size effect on the results.
Date: December 12, 2006
Creator: Chen, Y.Y.; Huang, P.H.; Ou, M.N.; Wang, C.R.; Yao, Y.D.; Lee,T.K. et al.
Partner: UNT Libraries Government Documents Department

Assessing the Importance of Using Biomodal Size Distribution for Ice Cloud Optical Property Parameterizations

Description: This report represents the final report for DE-AI02-0 IER63074. This work represented some follow-on work to that completed under DE-AI02-0 1 ER62669. The research reported here is undertaken in collaboration with Dr. David Mitchell of the Desert Research Institute in Reno, Nevada. The progress given here represents my contribution to his approach by providing radiative transfer expertise and calculations.
Date: March 31, 2006
Creator: Stackhouse, P. W.
Partner: UNT Libraries Government Documents Department

Remote Laser Diffraction PSD Analyzer

Description: Particle size distribution (PSD) analysis of radioactive slurry samples were obtained using a modified off-the-shelf classical laser light scattering particle size analyzer. A Horiba Instruments Inc. Model La-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a hot cell (gamma radiation) environment. The general details of the modifications to this analyzer are presented in this paper. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not achievable - making this technology far superior than the traditional methods used previously. Remote deployment and utilization of this technology is in an exploratory stage. The risk of malfunction in this radiation environment is countered by gaining of this tremendously useful fundamental engineering data. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.
Date: June 1, 2000
Creator: Batcheller, T. A.; Huestis, G. M. & Bolton, S. M.
Partner: UNT Libraries Government Documents Department

Parameterizing Size Distribution in Ice Clouds

Description: PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the ...
Date: September 25, 2009
Creator: DeSlover, Daniel & Mitchell, David L.
Partner: UNT Libraries Government Documents Department

Effects of ultrasonic bath treatment on HMX crystals

Description: Ultrasonic cleaning baths, common in many chemical laboratories, have been used to disperse particle agglomerates prior to automated particle size analysis and have been proposed for disassembly of consolidated powders of crystalline HMX (cyclotetramethylene-tetranitramine). This paper reports the effects of a Branson ultrasonic bath on coarse HMX crystals. Three experimental approaches are presented. The following observed effects are discussed: reduction of particle size, alteration of particle morphology, and fracture of individual crystals.
Date: December 31, 1996
Creator: Skidmore, C.B.
Partner: UNT Libraries Government Documents Department

Particle characterization: July--September, 1970

Description: The effect of particle size, shape and surface on the behavior of a powder is continually being studied. In quality control of a powder, seldom is a given parameter known well enough to predict accurately overall behavior of a powder. Therefore, many particle parameters must be evaluated to determine the influencing factors, including width, length/width ratio, volume, surface area, reentrant surface, bulk density, compressibility, surface roughness, pore volume, degree of sphericity, etc., and their relation to extrudability, pressability, firing performance, etc. Determining these things is called powder or particle characterization.
Date: 1970
Creator: Duncan, A. A.
Partner: UNT Libraries Government Documents Department

Impacts of Venturi Turbulent Mixing on the Size Distribution of Sodium Chloride and Dioctyl-Phthalate Aerosols

Description: Internal combustion engines are a major source of airborne particulate matter (PM). The size of the engine PM is in the sub-micrometer range. The number of engine particles per unit volume is high, normally in the range of 10{sup 12} to 10{sup 14}. To measure the size distribution of the engine particles dilution of an aerosol sample is required. A diluter utilizing a venturi ejector mixing technique is commercially available and tested. The purpose of this investigation was to determine if turbulence created by the ejector in the mini-dilutor changes the size of particles passing through it.
Date: August 1, 2000
Creator: Cheng, M.-D.; Wainman, T. & Storey, J.
Partner: UNT Libraries Government Documents Department

HE particle characterization. Quarterly report, October--December, 1971

Description: A comparison of data obtained in the Quality Division and the Development Division using the Fisher Sub-Sieve Sizer has been made. The results show no statistically significant difference between the two laboratories. The method of obtaining suitable photomicrographs for Zeiss particle analysis has been adapted to the Chemistry Laboratory equipment.
Date: December 31, 1971
Creator: Giberson, R.C.
Partner: UNT Libraries Government Documents Department

The Dependence of Cloud Particle Size on Non-Aerosol-Loading Related Variables

Description: An enhanced concentration of aerosol may increase the number of cloud drops by providing more cloud condensation nuclei (CCN), which in turn results in a higher cloud albedo at a constant cloud liquid water path. This process is often referred to as the aerosol indirect effect (AIE). Many in situ and remote sensing observations support this hypothesis (Ramanathan et al. 2001). However, satellite observed relations between aerosol concentration and cloud drop size are not always in agreement with the AIE. Based on global analysis of cloud effective radius (r{sub e}) and aerosol number concentration (N{sub a}) derived from satellite data, Sekiguchi et al. (2003) found that the correlations between the two variables can be either negative, or positive, or none, depending on the location of the clouds. They discovered that significantly negative r{sub e} - N{sub a} correlation can only be identified along coastal regions of the continents where abundant continental aerosols inflow from land, whereas Feingold et al. (2001) found that the response of r{sub e} to aerosol loading is the greatest in the region where aerosol optical depth ({tau}{sub a}) is the smallest. The reason for the discrepancy is likely due to the variations in cloud macroscopic properties such as geometrical thickness (Brenguier et al. 2003). Since r{sub e} is modified not only by aerosol but also by cloud geometrical thickness (H), the correlation between re and {tau}{sub a} actually reflects both the aerosol indirect effect and dependence of H. Therefore, discussing AIE based on the r{sub e}-{tau}{sub a} correlation without taking into account variations in cloud geometrical thickness may be misleading. This paper is motivated to extract aerosols' effect from overall effects using the independent measurements of cloud geometrical thickness, {tau}{sub a} and r{sub e}.
Date: March 18, 2005
Creator: Shao, H. & Liu, G.
Partner: UNT Libraries Government Documents Department

Current Development Status of a Particle Size Analyzer for Coated Particle Fuel

Description: Work was performed to develop a prototype Particle Size Analyzer (PSA) for application to coated particle fuel characterization. This system was based on a light obscuration method and targeted towards high throughput analysis. Although never matured to the point of replacing existing lower throughput optical microscopy shadowgraph methods, the system was successfully applied to automating the counting of large particle samples for increased accuracy in calculating mean particle properties based on measurements of multiparticle samples. The measurement of particle size with the PSA was compared to current shadowgraph techniques and found to result in considerably greater throughput at the cost of larger measurement uncertainty. The current algorithm used by the PSA is more sensitive to particle shape and this is a likely cause of the greater uncertainty when attempting to measure average particle diameter. The use of the PSA to measure particle shape will require further development. Particle transport through the PSA and stability of the light source/detector are key elements in the successful application of this technique. A number of system pitfalls were studied and addressed.
Date: August 1, 2007
Creator: Nelson, Andrew T; Hunn, John D & Karnowski, Thomas Paul
Partner: UNT Libraries Government Documents Department

Tandem Differential Mobility Analyzer/Aerodynamic Particle Sizer (APS) Handbook

Description: The tandem differential mobility analyzer (TDMA) is a single instrument that cycles through a series of complementary measurements of the physical properties of size-resolved submicron particles. In 2008, the TDMA was augmented through the addition of an aerodynamic particle sizer (APS), which extends the upper limit of the measured size distribution into the supermicron range. These two instruments are operated in parallel, but because they are controlled by a common computer and because the size distributions measured by the two are integrated in the produced datastreams, they are described together here. Throughout the day, the TDMA sequentially measures submicron aerosol size distributions and size-resolved hygroscopic growth distributions. More specifically, the instrument is operated as a scanning DMA to measure size distributions and as a TDMA to measure size-resolved hygroscopicity. A typical measurement sequence requires roughly 45 minutes. Each morning additional measurements are made of the relative humidity (RH) dependent hygroscopicity and temperature-dependent volatility of size-resolved particles. When the outside temperature and RH are within acceptable ranges, the hydration state of size-resolved particles is also characterized. The measured aerosol distributions complement the array of aerosol instruments in the Aerosol Observing System (AOS) and provide additional details of the light-scattering and cloud-nucleating characteristics of the aerosol.
Date: June 18, 2010
Creator: Collins, D.
Partner: UNT Libraries Government Documents Department

Simplified operation manual PA-720 particle counter

Description: The model PA-720 Automatic Particle Size Analyzer is a simple, relatively high speed device designed to provide accurate size distributions in both tabular and graphic forms. This model has two dynamic ranges; 50 to 2500 microns and 200 to 1600 microns. This is an abbreviated version of the manufacturer's operating manual. It provides all the necessary information for the novice and experienced user. For more detailed explanations and servicing procedures one should reference the full manual.
Date: September 8, 1980
Creator: Draper, V.F.
Partner: UNT Libraries Government Documents Department

Analysis of cloud radiative forcing and feedback in a climate GCM. Final report

Description: The principal objectives of the research supported at the Goddard Institute for Space Studies (GISS) by the Atmospheric Radiation Measurement (ARM) Program for a three year period commencing September 1990, were: (1) to improve and validate the radiation parameterizations in the GISS GCM through model intercomparisons with line-by-line calculations and through comparisons with ARM observations; (2) to improve the GISS GCM diagnostic output to enable more effective comparisons to global cloud/radiation data sets; and (3) to use ARM data to develop improved parameterization of clouds in the GCM and to study the interaction of dynamics and radiation. The ARM Program support has made it possible to establish and support an active and productive research group at GISS specializing in radiative transfer and cloud process modeling in support of improving the performance of a climate GCM.
Date: December 31, 1996
Creator: Lacis, A.
Partner: UNT Libraries Government Documents Department