Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 131 for “"Particle-size distributions"”.
-
Particle size distributions and stability of aqueous aerosols.
Thesis: M.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1975
-
Assessing fall velocity-maximum dimension relationships and particle size distributions for snowfall
… fall velocity and maximum dimension and the particle size distributions of snowflakes from many snowfall events were analyzed. Observed relationships between fall velocity and maximum dimension were compared with previously derived relationships, and it was found that, in most cases, no …
-
Evaluations of microphysical parameterizations in retrieval algorithms for snowfall particle size distributions from dual frequency radar measurements
… assumptions to constrain the shapes of snowflake particle size distributions. Previous algorithms that have been proposed for dual frequency retrievals assume that snowflakes have a constant density, scatter as homogeneous particles, and have an exponential size distribution. These assumptions …
-
Use of artificial neural network models to derive particle size distributions and their moments from chord length distributions
… to develop a method for in-lie measurement of a particle size distribution (PSD) of suspended solids and its moments. This was part of a wider study, the aim of which was to develop a system for controlling a crystallisation process. The control strategy to be used is dependent on kinetic models …
-
The use of gamma distributions to quantify the dependence of cloud particle size distributions in hurricanes on cloud and environmental conditions
… used in such models make assumptions about the size distributions (SDs) of different ice species, such as cloud ice, graupel, and snow, which have typically not been based on observations obtained in TCs. The representativeness of these parameterizations for TCs is not well known. In this study, …
-
The Stability and Drug Release Characteristics of Multiple Emulsions
… been studied by a number of methods. Bimodal particle size distributions were produced containing oil and multiple droplets. The proportions of these two types of droplets was important as it determined the degree to which the emulsion behaved as a multiple emulsion. The particle size …
-
Millimeter Through Visible Frequency Waves Through Aerosols: Particle Modeling, Reflectivity and Attenuation
… atmospheric aerosol (such as haze and fog) particle-size distributions in order to predict the effects (such as attenuation and reflectivity) that these particles have upon the propagation of electromagnetic waves of micrometer range wavelengths. Specifically, an inversely proportional to …
-
Nanocomposite thermite powders with improved flowability prepared by mechanical milling
… properties of the thermite powders such as their particle size distributions, particle shapes, and powder flowability. For example, an improved flowability is desired to use these powders as feedstock in additive manufacturing. Arrested reactive milling (ARM) offers a versatile and practical …
-
Chromatography of Latex Particles in Packed Columns (Hydrodynamic, Dispersion)
… development in the characterization of colloidal particles has been the adaptation of liquid chromatography techniques to the determination of particle size distributions of polymer latexes. In this work, techniques that involve packed columns with either nonporous packing material (termed …
-
Quantitative electron microscopy of supported subnanometer clusters
Small supported particles (a few angstroms in diameter) are useful as catalysts because of their increased surface area for a given volume of material. Their catalytic activity and selectivity depends upon their size, which determines their electronic structure. Therefore, it is vital to reliably …
-
Modified Release of Agglomerated Nano-Particles for Pulmonary Drug Delivery
… pulmonary route presents many challenges. Nanoparticles tend to lack sufficient mass and are principally exhaled and not deposited in the lungs. However, they also tend to form aggregates or agglomerates to reduce the free energy of the system due to the large surface. Optimal deposition in the …
-
Sub 2 nm Particle Characterization in Systems with Aerosol Formation and Growth
… frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring …
-
Polycondensation of Bridged Amino-Functionalized Trialkoxysilanes.
… and possess a high thermostability. Study of particle size distributions showed that in all cases it was bimodal. The largest particles formed in basic media. Mesoporous silsesquioxanes were obtained from bridged alkyltrimethoxysilanes in the presence of surfactants.</p>
-
Modeling Size-Resolved Particle Number Emissions From Advanced Technology And Alternative Fueled Vehicles In Real-Operating Conditions
Two particle number emission datasets were analyzed in detail. The first data set contained particle number emissions from four transit buses, including two hybrid diesel-electric buses, under a variety of driving conditions and technological/fuel treatments including: diesel oxidation catalysts, …
-
Particle size prediction in reactive precipitation processes
… in this system.;In order to accurately predict particle size distributions (PSDs) in precipitation reactions, local variations in hydrodynamics, degree of supersaturation, and particle size distributions need to be accurately tracked. Discretized Population Balance (DPB) methods can accurately …
-
Coagulation between fractal aggregates and small particles and fractal properties of marine particles
… aggregates (200-1000 μm) and small (1.48 μm) particles were studied for collisions induced by differential sedimentation and turbulent fluid shear. The collision frequency functions (beta) between these aggregates and small particles were found to be lower than predicted by a rectilinear …
-
Relationships between sludge specific resistance, coefficient of compressibility, blinding coefficient and vacuum filter yield
The relationships between an activated sludge's particle size distribution and its specific resistance were investigated. Particle size distributions were rearranged by sludge storage, replacing sludge supernatant with alum sludge supernatant, and by polymer conditioning. Specific resistance was …
-
Evaluation of an Aerodynamic Particle Sizer With Certified Polydisperse Test Dusts
<p>The Aerodynamic Particle Sizer (APS) is a near real time laser particle sizer that counts and sizes particles in the range of 0.5 /xm to 3 0 /xm, which makes it ideal for measuring the particle size distribution of fly ash from coal combustion. While the APS has proven to be a valuable …
-
Development of an unsteady state model for the tank bioleaching of sulphide mineral concentrates in flow reactor systems
In this thesis, it is hypothesized that in bioleaching flow reactor systems, high reaction rate regions exist that can be maintained by application of biological stress trajectories. Reactor models are developed for the purpose of optimising plant operation, understood here as maximising the …
-
Quantitative Photoacoustic Reaction-Rate Measurements Under Microcomputer Control
… oxide was prepared by simply mixing controlled particle size distributions of samarium oxide and barium sulfate.
Page 1 of 7