3,112 research outputs found
Bio-Processes of the Oxidation Ditch When Subjected to a Sub-Arctic Climate
Alaska's far northern area is sparsely populated primarily because of a
severe climate which varies from northern temperate to Arctic. Construction
and power costs are high. Skilled operating personnel are scarce and
expensive, if available. Receiving streams are said to be delicate, particularily
in the winter, when little possibility for reaeration exists due to a total ice cover. The oxidation ditch modification of the extended aeration activated sludge process appears to be well suited for the
treatment of wastes in this environment. Past operating data on a plant
of this type located in Interior Alaska (near Fairbanks) indicated it may
be well suited to treat small volumes of domestic waste economically,
with low sludge production, and minimal sensitivity to low temperatures.The work reported on herein was done under Contract No. RFP DACA 897l-
R-0006 from the U. S. Army Cold Regions Research and Engineering
Laboratory, Hanover, New Hampshire
Spin dynamics and frequency dependence of magnetic damping study in soft ferromagnetic FeTaC film with a stripe domain structure
Perpendicular magnetic anisotropy (PMA) and low magnetic damping are the key
factors for the free layer magnetization switching by spin transfer torque
technique in magnetic tunnel junction devices. The magnetization precessional
dynamics in soft ferromagnetic FeTaC thin film with a stripe domain structure
was explored in broad band frequency range by employing micro-strip
ferromagnetic resonance technique. The polar angular variation of resonance
field and linewidth at different frequencies have been analyzed numerically
using Landau-Lifshitz-Gilbert equation by taking into account the total free
energy density of the film. The numerically estimated parameters Land\'{e}
-factor, PMA constant, and effective magnetization are found to be 2.1,
2 erg/cm and 7145 Oe, respectively. The frequency
dependence of Gilbert damping parameter () is evaluated by considering
both intrinsic and extrinsic effects into the total linewidth analysis. The
value of is found to be 0.006 at 10 GHz and it increases with
decreasing precessional frequency.Comment: 5 Pages, 6 Figures, Regular Submissio
Thermo-Chemical Modelling of the Production of Ferro-chromium in Submerged-Arc Furnace
Several studies have been reported in literature on
the thermochemistry of production of ferro-chromium. Experimental studies have been carried out to understand the kinetics of reduction of oxides and to study the equilibrium between slag and metal in the furnace. How-ever, a quantitative model of the thermochemistry of the process in any region of the furnace is yet to be repor-ted. Pre-reduction of the ore has been recommended and also employed as a means of reducing the power consumption in the furnace is yet to explored. This communication reports a thermochemical model for the production of ferro-chromium in submerged-arc furnace and a model to map the temperature profile in the furnace. The neffect of pre-reduction on the temperature profile has also been asse-ssed
The mouth and AIDS: lessons learned and emerging challenges in global oral health: introduction
National Institutes of Dental and Craniofacial Research (NIDCR) (Grant Number: 1U13DE024696-0
Exploratory Analysis of Highly Heterogeneous Document Collections
We present an effective multifaceted system for exploratory analysis of
highly heterogeneous document collections. Our system is based on intelligently
tagging individual documents in a purely automated fashion and exploiting these
tags in a powerful faceted browsing framework. Tagging strategies employed
include both unsupervised and supervised approaches based on machine learning
and natural language processing. As one of our key tagging strategies, we
introduce the KERA algorithm (Keyword Extraction for Reports and Articles).
KERA extracts topic-representative terms from individual documents in a purely
unsupervised fashion and is revealed to be significantly more effective than
state-of-the-art methods. Finally, we evaluate our system in its ability to
help users locate documents pertaining to military critical technologies buried
deep in a large heterogeneous sea of information.Comment: 9 pages; KDD 2013: 19th ACM SIGKDD Conference on Knowledge Discovery
and Data Minin
Nearby CFT's in the operator formalism: The role of a connection
There are two methods to study families of conformal theories in the operator
formalism. In the first method we begin with a theory and a family of deformed
theories is defined in the state space of the original theory. In the other
there is a distinct state space for each theory in the family, with the
collection of spaces forming a vector bundle. This paper establishes the
equivalence of a deformed theory with that in a nearby state space in the
bundle via a connection that defines maps between nearby state spaces. We find
that an appropriate connection for establishing equivalence is one that arose
in a recent paper by Kugo and Zwiebach. We discuss the affine geometry induced
on the space of backgrounds by this connection. This geometry is the same as
the one obtained from the Zamolodchikov metric.Comment: 24 pp, CTP#215
An algorithm for generating quasiperiodic patterns and their approximants
An algorithm for projecting the interior of a hypercube in N-dimensions on to an m-dimensional subspace has been developed and incorporated into a computer program for generating quasiperiodic and periodic patterns in an n-dimensional subspace. Some aspects of the resulting orthorhombic approximants to Penrose tiling patterns are discussed and illustrated
Mathematical modelling and the influence of process para-meters on the temperature profile in a submerged arc furnace producing ferro-chromium
Control of the temperature profile is a crucial factor
for optimising the energy consumption and regulating the quality of the hot metal produced in submerged arc furn-ace. Factors such as the heat generated at the electrodes, the heat loss, the heat consumed by chemical reactions,
the packing density of the charge materials etc. deter-mine the profile. This in turn decides the production
rate and the chemistry of the hot metal. Controlling the level of impurities in the hot metal such as the level of silicon in ferro-chromium can be achieved through the mapping of the temperature profile and regulating the
process accordingly. The communication describes the mathematical modelling of the temperature profile in the submerged arc furnace and analyses the influence of several process parameters on the same
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