164 research outputs found
A study of some raw materials for the manufacture of silica brick
The ability of silica to carry a load to within a few degrees of its melting point and its tolerance for comparatively high concentrations of iron oxide and lime, have enabled it to maintain its position as the number one steelplant refractory. It is estimated that at least half of the volume of refractories used in the steel plant are silica bricks. Consequently the manufacture of silica refractories forms an industry of considerable importance.
Raw materials suitable for the manufacture of silica brick are widely distributed, but only a small number of deposits are used commercially for one reason or another.
Many workers have listed properties of raw materials necessary to permit their use in the manufacture of silica brick. The lists of important properties are strikingly similar. The order of importance is less definite, and the reason for each property and correlation between the properties of the raw materials and desirable properties in the finished product are much confused and the reports often contradictory.
Reports that a certain raw material is highly suited to the manufacture of silica brick seldom specify the exact type of brick that is to be made from the material. A brick unsuited for one application may give superior results in another. For continuous use at very high temperature a brick of pure cristobalite may be preferred to one of pure tridymite and even unconverted quartz is an excellent refractory in some instances.
There seems to be common agreement, however, at the present time that a high percentage of tridymite is desirable as a general rule due to the fact that the brick are very often mishandled in use. The high tridymite brick is more \u27fool proofâ than ones with only quartz and cristobalite present....
In view of the contradictions existing in the literature it was decided to compare, by means of the x-ray spectrometer, the South African Silcrete with some American raw materials as regards the rate of inversion to tridymite --Introduction, pages 1, 2, 4
CREATING A $40 MILLION COMPANY BASED ON DISPERSION MODELLING
Starting in 1974, the author grew Trinity Consultants, Inc. from a one-person firm to one employing over 270 staff in 22
offices scattered across the United States and an added office in the Peopleâs Republic of China. Trinity became the leading US firm
in the field of air quality consulting and compliance. The foundation of the firm was in the field of dispersion modelling and the
author taught a course, which he continually revised, entitled âFundamentals of Dispersion Modelingâ more than 200 times in the United States and in more than a dozen countries on five continents. He also authored a 400-page textbook with D. Bruce Turner on this subject in 2007. This paper describes three selected aspects of this experience that spanned a third of a century until controlling interest of Trinity Consultants was sold to a private equity firm in November 2007. The three areas to be described are: a) an
assessment by the author of the human qualities that foster success as an entrepreneur, b) the stages of growth of a professional
services firm, and c) the process of ownership transfer and the financial engineering that was involved
Scaling Law and Aging Phenomena in the Random Energy Model
We study the effect of temperature shift on aging phenomena in the Random
Energy Model (REM). From calculation on the correlation function and simulation
on the Zero-Field-Cooled magnetization, we find that the REM satisfies a
scaling relation even if temperature is shifted. Furthermore, this scaling
property naturally leads to results obtained in experiment and the droplet
theory.Comment: 8 pages, 7 figures, to be submitted to J. Phys. Soc. Jp
Memory Effect, Rejuvenation and Chaos Effect in the Multi-layer Random Energy Model
We introduce magnetization to the Multi-layer Random Energy Model which has a
hierarchical structure, and perform Monte Carlo simulation to observe the
behavior of ac-susceptibility. We find that this model is able to reproduce
three prominent features of spin glasses, i.e., memory effect, rejuvenation and
chaos effect, which were found recently by various experiments on aging
phenomena with temperature variations.Comment: 10 pages, 14 figures, to be submitted to J. Phys. Soc. Jp
Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) III. Star formation properties of the host galaxies at studied with ALMA
We present our ALMA Cycle 4 measurements of the [CII] emission line and the
underlying far-infrared (FIR) continuum emission from four optically
low-luminosity () quasars at discovered by
the Subaru Hyper Suprime Cam (HSC) survey. The [CII] line and FIR continuum
luminosities lie in the ranges
and , which are at least one
order of magnitude smaller than those of optically-luminous quasars at . We estimate the star formation rates (SFR) of our targets as
. Their line and continuum-emitting
regions are marginally resolved, and found to be comparable in size to those of
optically luminous quasars, indicating that their SFR or likely gas mass
surface densities (key controlling parameter of mass accretion) are accordingly
different. The ratios of the hosts, , are fully consistent with local star-forming
galaxies. Using the [CII] dynamics, we derived their dynamical masses within a
radius of 1.5-2.5 kpc as . By
interpreting these masses as stellar ones, we suggest that these faint quasar
hosts are on or even below the star-forming main sequence at , i.e.,
they appear to be transforming into quiescent galaxies. This is in contrast to
the optically luminous quasars at those redshifts, which show starburst-like
properties. Finally, we find that the ratios of black hole mass to host galaxy
dynamical mass of the most of low-luminosity quasars including the HSC ones are
consistent with the local value. The mass ratios of the HSC quasars can be
reproduced by a semi-analytical model that assumes merger-induced black
hole-host galaxy evolution.Comment: 20 pages, 9 figures, 4 tables. Accepted for publication in PAS
A High-Throughput Enzyme Assay for Organophosphate Residues in Milk
A rapid, high-sensitivity, chemiluminescence (CL) enzyme assay for the determination of organophosphate (OP) residues in milk is presented. The assay for quantification of OP residues in milk is based on the inhibition of enzyme butyrylcholinesterase (BuChE). BuChE was stabilized and preloaded in 384 well plates at 30 °C. The assay permits rapid determination of OPs in milk within 12 min including an incubation step. The enzyme assay was tested for individual and mixtures of OPs such as methyl paraoxon (MPOx), methyl parathion (MP) and malathion (MT) in milk to evaluate their synergistic effect on BuChE inhibition. Good linearity was obtained in the range 0.005â50 ÎŒg·Lâ1 for MPOx and 0.5â1,000 ÎŒg·Lâ1 for MP as well as MT in milk. Mean recovery of 93.2%â98.6% was obtained for MPOx spiked milk samples with 0.99%â1.67% reproducibility (RSD). The proposed method facilitated rapid screening of milk samples in 384 well plate formats with further miniaturization presented in 1,536 well plates
Precision Determination of the Neutron Spin Structure Function g1n
We report on a precision measurement of the neutron spin structure function
using deep inelastic scattering of polarized electrons by polarized
^3He. For the kinematic range 0.014<x<0.7 and 1 (GeV/c)^2< Q^2< 17 (GeV/c)^2,
we obtain at an average . We find relatively large negative
values for at low . The results call into question the usual Regge
theory method for extrapolating to x=0 to find the full neutron integral
, needed for testing quark-parton model and QCD sum rules.Comment: 5 pages, 3 figures To be published in Phys. Rev. Let
The Spin Structure of the Nucleon
We present an overview of recent experimental and theoretical advances in our
understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure
Two naphthalene degrading bacteria belonging to the genera Paenibacillus and Pseudomonas isolated from a highly polluted lagoon perform different sensitivities to the organic and heavy metal contaminants
Two bacterial strains were isolated in the presence of naphthalene as the sole carbon and energy source from sediments of the Orbetello Lagoon, Italy, which is highly contaminated with both organic compounds and metals. 16S rRNA gene sequence analysis of the two isolates assigned the strains to the genera Paenibacillus and Pseudomonas. The effect of different contaminants on the growth behaviors of the two strains was investigated. Pseudomonas sp. ORNaP2 showed a higher tolerance to benzene, toluene, and ethylbenzene than Paenibacillus sp. ORNaP1. In addition, the toxicity of heavy metals potentially present as co-pollutants in the investigated site was tested. Here, strain Paenibacillus sp. ORNaP1 showed a higher tolerance towards arsenic, cadmium, and lead, whereas it was far more sensitive towards mercury than strain Pseudomonas sp. ORNaP2. These differences between the Gram-negative Pseudomonas and the Gram-positive Paenibacillus strain can be explained by different general adaptive response systems present in the two bacteria
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