38,558 research outputs found
Surfactant-assisted liquefaction of particulate carbonaceous substances
A slurry of carbonaceous particles such as coal containing an oil soluble polar substituted oleophilic surfactant, suitably an amine substituted long chain hydrocarbon, is liquefied at high temperature and high hydrogen presence. The pressure of surfactant results in an increase in yield and the conversion product contains a higher proportion of light and heavy oils and less asphaltene than products from other liquefaction processes
Coal desulfurization
Organic sulfur is removed from coal by treatment with an organic solution of iron pentacarbonyl. Organic sulfur compounds can be removed by reaction of the iron pentacarbonyl with coal to generate CO and COS off-gases. The CO gas separated from COS can be passed over hot iron fillings to generate iron pentacarbonyl
Fluidized-bed development at JPL
Silicon deposition on silicon seed particles by silane pyrolysis in a fluidized bed reactor (FBR) was investigated as a low cost, high throughput method to produce high purity polysilicon for solar cell applications. The emphasis of the research is fundamental understanding of fluidized bed silicon deposition. The mechanisms involved were modeled as a six-path process: heterogeneous deposition; homogeneous decomposition; coalescence; coagulation; scavenging; and chemical vapor deposition growth on fines
Space-time translational gauge identities in Abelian Yang-Mills gravity
We derive and calculate the space-time translational gauge identities in
quantum Yang-Mills gravity with a general class of gauge conditions involving
two arbitrary parameters. These identities of the Abelian group of translation
are a generalization of Ward-Takahasi-Fradkin identities and important for
general discussions of possible renormalization of Yang-Mills gravity with
translational gauge symmetry. The gauge identities in Yang-Mills gravity with a
general class of gauge conditions are substantiated by explicit calculations.Comment: 15 pages. To be published in The European Physical Journal - Plus
(2012
Numerical studies of interacting vortices
To get a basic understanding of the physics of flowfields modeled by vortex filaments with finite vortical cores, systematic numerical studies of the interactions of two dimensional vortices and pairs of coaxial axisymmetric circular vortex rings were made. Finite difference solutions of the unsteady incompressible Navier-Stokes equations were carried out using vorticity and stream function as primary variables. Special emphasis was placed on the formulation of appropriate boundary conditions necessary for the calculations in a finite computational domain. Numerical results illustrate the interaction of vortex filaments, demonstrate when and how they merge with each other, and establish the region of validity for an asymptotic analysis
Crude oil desulfurization
High sulfur crude oil is desulfurized by a low temperature (25-80 C.) chlorinolysis at ambient pressure in the absence of organic solvent or diluent but in the presence of water (water/oil=0.3) followed by a water and caustic wash to remove sulfur and chlorine containing reaction products. The process described can be practiced at a well site for the recovery of desulfurized oil used to generate steam for injection into the well for enhanced oil recovery
Invisible Higgs boson, continuous mass fields and unHiggs mechanism
We explore the consequences of an electroweak symmetry breaking sector which
exhibits approximately scale invariant dynamics -- i.e., nontrivial fixed point
behavior, as in unparticle models. One can think of an unHiggs as a composite
Higgs boson with a continuous mass distribution. We find it convenient to
represent the unHiggs in terms of a Kallen-Lehmann spectral function, from
which it is simple to verify the generation of gauge boson and fermion masses,
and unitarization of WW scattering. We show that a spectral function with broad
support, which corresponds to approximate fixed point behavior over an extended
range of energy, can lead to an effectively invisible Higgs particle, whose
decays at LEP or LHC could be obscured by background.Comment: 8 page
Diffusion of Common Application Membership and Admissions Outcomes at American Colleges and Universities
We study the adoption of Common Application membership by private four-year postsecondary institutions and its role in explaining the growth in undergraduate applications. Using data from the College Board’s Annual Survey of Colleges, proportional hazards models suggest that institutions respond to the net benefit of adoption. We then estimate that membership increases applications by 5.7–7.0 percent and decreases yield rates by 2.8–3.9 percent. Acceptance rates decrease for members when their local networks are large. Falsification tests indicate that membership effects occur as a one-time adoption shock. Membership also decreases SAT scores and increases the percent students of color
Coal desulfurization process
A method for chlorinolysis of coal is an organic solvent at a moderate temperautre and atmospheric pressure has been proven to be effective in removing sulfur, particularly the organic sulfur, from coal. Chlorine gas is bubbled through a slurry of moist coal in chlorinated solvent. The chlorinated coal is separated, hydrolyzed and the dechlorinated. Preliminary results of treating a high sulfutr (4.77%S) bituminous coal show that up to 70% organic sulfur, 90% hyritic sulfur and 76% total sulfur can be removed. The treated coal is dechlorinated by heating at 500 C. The presence of moisture helps to remove organic sulfur
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