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 114 for “"ultrafine"”.
-
Miniaturization of Electrical Ultrafine Particle Sizers
<p>Nanoparticles, or ultrafine particles, have potential risks for human health, and the adverse health effects caused by ultrafine particles have been proven to be size related. To meet the increasing demanding for personal exposure monitoring and spatial distribution measurements of ultrafine …
-
The erosion of ultrafine WC-Co
A series of four ultrafine WC-Co alloys of varying cobalt contents has been sintered from powder produced through the spray conversion process. The materials have been characterised and subjected to slurry erosion and cavitation erosion. A further twelve WC-Co alloys of varying grain sizes and …
-
Low Temperature Drying of Ultrafine Coal
… drying, has been developed to remove water from ultrafine (minus 325 mesh) coal particles. The process subjects partially dewatered solids to intense mechanical shearing in the presence of unsaturated air. Theoretical analysis of the thermodynamic properties of water indicates residual surface …
-
Ultrafine aerosol deposition in planar channel flow
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.
-
Developing a Novel Ultrafine Coal Dewatering Process
Dewatering fine coal is needed in many applications but has remained a great challenge. The hydrophobic-hydrophilic separation (HHS) method is a powerful technology to address this problem. However, organic solvents in solvent-coal slurries produced during HHS must be recovered for the method to be …
-
The cleaning of ultrafine coal using microbubbles
Mechanized mining techniques that are commonly used in the coal industry produce a large amount of fine particles. These fines are extremely difficult to recover by conventional flotation methods, mainly because of the large size of the bubbles produced relative to the size of the particles. …
-
The fracture toughness of ultrafine WC-Co Alloys
… from 0 to 0.8wt%. A series of twenty-four ultrafine WC-Co alloys were sintered from powders produced through three different production routes, namely, the spray conversion process and two variations of the conventional powder production methods. A further twelve WC-Co alloys with three …
-
A liberation study on ultrafine South African coals
South African coal mines generate large quantities of fines as a result of the increased use of mechanised mining methods. Generally, these fines are discarded. They do however contain relatively large proportions of high grade material, which provides a considerable incentive for their …
-
Continuous column flotation of ultrafine coal using microbubbles
A flotation column has been developed Incorporating the use of fine air bubbles (less than 100 microns) to remove ash-forming minerals from micronized coal. The microbubble generator used In this work has been characterized and found to yield a very narrow size distribution. Microbubble column …
-
Radio frequency plasma synthesis of ultrafine titanium carbide powders
… the use thermal plasma processing to synthesise ultrafine TiCx, TiNy, and TiCxNy powders from locally available TiO2, natural gas and NH3. The objectives for the work reported in this thesis were to develop and test the necessary experimental apparatus for a process for synthesis of the ultrafine …
-
Hydrophobic-Hydrophilic Separation Process for the Recovery of Ultrafine Particles
… mineral particles in these resources are ultrafine in size, which poses considerable challenges to the most widely used fine particle beneficiation technique, i.e., froth flotation. A novel technology called the Hydrophobic-Hydrophilic Separation (HHS) process, developed at Virginia Tech, …
-
Microstructure development and fracture behavior of plate steels containing ultrafine ferrite
Includes bibliographical references (pages 163-168).
-
Development of the selective-shear coagulation process for ultrafine coal cleaning
… an advanced physical cleaning technique for ultrafine coal, called"selective-shear coagulation", is presently being investigated. The process utilizes high shear conditions to overcome the strong electrostatic repulsive force between particles. The attractive hydrophobic interaction and van …
-
An evaluation of separation methods for the selective coagulation of ultrafine coal
A novel technique for selectively coagulating and separating coal from dispersed mineral matter has been developed at Virginia Tech. The process, which is known as Selective Hydrophobic Coagulation (SHC), differs from oil agglomeration, shear or polymer flocculation, and electrolytic coagulation …
-
Stress corrosion cracking behavior of friction stir processed ultrafine grained light metal alloys
… and power law type behavior was proposed. Ultrafine fine grained (UFG) microstructure showed one order magnitude lower corrosion rate.</p> <p>Grain refinement achieved through different FSP parameters showed lower corrosion currents for Al-Mg alloy as compared to the base alloy. The …
-
Excess thermodynamic properties and size-dependent segregation phenomena in ultrafine-grained titanium dioxide
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1993.
-
Synthesis, microstructure and mechanical properties of bulk ultrafine grained Ti-47Al-2Cr (at%) alloy
… (at%) have been carried out to synthesize bulk ultrafine grained Ti-47Al-2Cr alloy. The Ti/Al/Cr composite powders were produced using high energy mechanical milling of elemental Ti, Al, Cr powders in a retsch planetary mill. The microstructure and mechanical properties of the bulk consolidated …
-
Precipitation of ultrafine particles using liquid antisolvent with concentric ultrasonic nozzle and subcritical CO2
… using subcritical CO_2 have been used to produce ultrafine particles of this drug. In liquid antisolvent precipitation, a combination of ultrasound, polymer and surfactant is used to precipitate ultrafine particles. Ultrasound is used to increase the nucleation rate by enhancing the micro mixing …
-
The effect of particle size distribution on the rheology of ultrafine coal-water slurries
… can be eliminated by the utilization of this ultrafine coal in a slurry form. Ultrafine coal-water slurries, prepared from an Eastern bituminous coal, are investigated to determine the effect of size distribution on slurry rheology. The effect of reagent addition on slurry rheology is …
-
Processing of Low Rank Coal and Ultrafine Particle Processing by Hydrophobic-Hydrophilic Separation (HHS)
… by flotation. The HHS process was also tested on ultrafine mono-sized silica beads. The results were superior to those obtained by flotation, particularly with ultrafine particles. The HHS process has also been tested successfully for upgrading subbituminous coals. Low-rank coals are not as …
Page 1 of 6