Chemically resistant steellwith special reference to very high and very low temperatures

1926 ◽  
Vol 45 (31) ◽  
pp. 526-534
Author(s):  
T. C. Elliott ◽  
C. B. Willey
Keyword(s):  
Special Reference ◽  
Low Temperatures ◽  
Very High

scholarly journals Forging, textures, and deformation systems in a B2 FeAl alloy

1999 ◽  
Vol 14 (3) ◽  
pp. 715-728 ◽  
Author(s):  
P. Zhao ◽  
D. G. Morris ◽  
M. A. Morris Munoz
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Slip System ◽  
High Temperatures ◽  
Low Temperatures ◽  
High Speed ◽  
Deformation Texture ◽  
Slip Systems ◽  
Feal Alloy ◽  
Very High

High-temperature forging experiments have been carried out by axial compression testing on a Fe–41Al–2Cr alloy in order to determine the deformation systems operating under such high-speed, high-temperature conditions, and to examine the textures produced by such deformation and during subsequent annealing to recrystallize. Deformation is deduced to take place by the operation of 〈111〉 {110} and 〈111〉{112} slip systems at low temperatures and by 〈100〉{001} and 〈100〉{011} slip systems at high temperatures, with the formation of the expected strong 〈111〉 textures. The examination of the weak 〈100〉 texture component is critical to distinguishing the operating slip system. Both texture and dislocation analyses are consistent with the operation of these deformation systems. Recrystallization takes place extremely quickly at high temperatures (above 800 °C), that is within seconds after deformation and also dynamically during deformation itself. Recrystallization changes the texture such that 〈100〉 textures superimpose on the deformation texture. The flow stress peak observed during forging is found at a very high temperature. Possible origins of the peak are examined in terms of the operating slip systems.

A study of chromium-exchanged zeolites as potential catalysts for thermolysis of water

1986 ◽  
Vol 64 (7) ◽  
pp. 1332-1339 ◽  
Author(s):  
K. M. Miedzinska ◽  
B. R. Hollebone
Keyword(s):  
Low Temperatures ◽  
Metal Ion ◽  
Redox Cycle ◽  
Zeolite 13X ◽  
Irreversible Reduction ◽  
Very High ◽  
Oxygen Atoms

Evidence was found that the Cr(III)/Cr(II) redox cycle previously described to occur upon dehydration and rehydration of exchanged zeolite 13X, does not occur reversibly. Data suggest dimerization of the metal ion at high levels of exchange. The bridging provideu by the oxygen atoms of the lattice probably stabilize these dimers and lead to initial but irreversible reduction at very low temperatures. Evidence also indicates irreversible formation of new lattices at very high dehydration temperatures.

The Chorioidal Tapeta of some Cartilaginous Fishes (Chondrichthyes)

1964 ◽  
Vol 44 (1) ◽  
pp. 219-258 ◽  
Author(s):  
E. J. Denton ◽  
J. A. C. Nicol
Keyword(s):  
Special Reference ◽  
Incident Light ◽  
Squalus Acanthias ◽  
Inside Surface ◽  
Retinal Rods ◽  
Cartilaginous Fishes ◽  
Metallic Mirror ◽  
Very High ◽  
The Way

1. A study of the histology of the eyes of some cartilaginous fishes has been made with special reference to their reflecting tapeta.2. The rate and way in which the pigment in the melanophores spreads over the reflecting cells of the tapetum ofSqualus acanthiaswhen it is lightadapted are described.3. The reflecting plates in the tapeta are about parallel to the plane of the retina in the centre of the eye, but as we move towards the periphery they become more oblique, until near the ora they are almost perpendicular to the plane of the retina. It is shown that when we take account of the way in which the pupil limits the light which can reach the retina in all these situations the plates are arranged to be roughly perpendicular to the incident light. They reflect light either back through the pupil or on to the very black inside surface of the iris and do not scatter it to other parts of the eye.4. The reflectivity of tapeta for various angles and various wave-lengths of light has been found by several different methods, and a new and simple way of measuring the reflectivity of natural tissues is described. For the blue and green lights which will be those reaching the eye in life the reflectivity is very high, over 80%, and so approaches that of a good metallic mirror.5. The external segments of the retinal rods of cartilaginous fishes which have well-developed tapeta are only about half as long as those of other fish living in the same environment, and the retinal optical densities of photosensitive pigments in these fish are only about a half of those of fish without reflecting tapeta.

A Data Analysis of the Irradiation Parameter D10 for Bacteria and Spores under Various Conditions

1999 ◽  
Vol 62 (9) ◽  
pp. 1024-1032 ◽  
Author(s):  
SUZANNE J. C. van GERWEN ◽  
FRANK M. ROMBOUTS ◽  
KLAAS van't RIET ◽  
MARCEL H. ZWIETERING
Keyword(s):  
Low Temperatures ◽  
Deinococcus Radiodurans ◽  
Specific Question ◽  
Factors Influencing ◽  
Specific Factors ◽  
Irradiation Parameter ◽  
Irradiation Process ◽  
Very High ◽  
Relevant Factors

This paper provides approximate estimates for the irradiation parameter D10 to globally predict the effectiveness of any irradiation process. D10 is often reported to depend on many specific factors, implying that D10 cannot be estimated without exact knowledge of all factors involved. For specific questions these data can of course be useful but only if the conditions reported exactly match the specific question. Alternatively, this study determined the most relevant factors influencing D10, by quantitatively analyzing data from many references. The best first step appeared to be a classification of the data into vegetative bacteria and spores. As expected, spores were found to have significantly higher D10 values (average 2.48 kGy) than vegetative bacteria (average 0.762 kGy). Further analyses of the vegetative bacteria confirmed the expected extreme irradiation resistance of nonpathogenic Deinococcus radiodurans (average 10.4 kGy). Furthermore the analysis identified Enterococcus faecium, Alcaligenes spp., and several members of the Moraxella–Acinetobacter group as having very high resistance at very low temperatures (average 3.65 kGy). After exclusion of high- and low-resistance spores and some specific conditions showing relevant high or low D10 values, the average for spores was estimated to be 2.11 kGy. For vegetative bacteria this average was estimated to be 0.420 kGy. These approximate estimates are not definite, as they depend on the data used in the analyses. It is expected that inclusion of more data will not change the estimates to a great extent. The approximate estimates are therefore useful tools in designing and evaluating irradiation processes.

Modelling and parametric investigation of NOx reduction by oxidation precatalyst-assisted ammonia-selective catalytic reduction

2009 ◽  
Vol 223 (9) ◽  
pp. 1193-1206 ◽  
Author(s):  
S-C Jung ◽  
W-S Yoon
Keyword(s):  
Selective Catalytic Reduction ◽  
Low Temperatures ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Volume Ratio ◽  
Kinetic Scheme ◽  
Space Velocity ◽  
Gas Temperature ◽  
Scr System ◽  
Very High

Nitrogen oxide (NO x) reduction by the selective catalytic reduction (SCR) system assisted by an oxidation precatalyst is modelled and analytically investigated. The Langmuir—Hinshelwood SCR kinetic scheme with vanadium-based catalyst and ammonia (NH3) reductant in conjunction with the NO—NO2 conversion reaction over a platinum-based catalyst is used. The effects of the ratio of the oxidation precatalyst to the SCR monolith volume, the gas temperature, the space velocity, and the NH3-to-NO x concentration ratio on the de-NO x performance are parametrically examined. The oxidation precatalyst promotes NO x conversion at low temperatures. At intermediate temperatures, the NO x reduction is either activated or deactivated with increase in the space velocity. A higher oxidation precatalyst-to-SCR monolith volume ratio tends to promote the NO x reduction of higher space velocities. At high temperatures, the de-NO x efficiency is very high and insensitive to the space velocity. The NO x conversion efficiency depends on the NH3-to-NO x ratio at low temperatures.

Applications: Light My Fire

1982 ◽  
Vol 75 (1) ◽  
pp. 53-55
Author(s):  
George Knill ◽  
George Fawceti
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Chemical Process ◽  
Room Temperature ◽  
Very High

Everyone knows that wood bums at a very high temperature. This burning is a chemical process that combines oxygen and carbon. The process occurs at very low temperatures as well as at very high ones. At high temperatures the process is spectacular-fire. At low temperatures (room temperature) you won’t even notice it, although it is still going on. Wood is always burning.

scholarly journals An experiment with the balance to find if change of temperature has any effect upon weight

1905 ◽  
Vol 76 (512) ◽  
pp. 445-457 ◽  
Keyword(s):  
Low Temperatures ◽  
Secondary Effect ◽  
Boiling Liquid ◽  
The Earth ◽  
Exact Determination ◽  
The Mean ◽  
Very High ◽  
The Ideal

In all the experiments hitherto made to determine the gravitative attraction between two masses, the temperature has not varied more than a few degrees, and there are no results which would enable us to detect with certainty any dependence of attraction upon temperature even if such dependence exists. It is true, as Professor Hicks has pointed out, that Baily’s results for the Mean Density of the Earth, if arranged in the order of the temperature of the apparatus when they were obtained, show a fall in value as the temperature rises. But this is almost certainly some secondary effect, due to errors in the measurements of the apparatus, or to the seasons at which different attracted masses were used. The ideal experiment to find if temperature has an effect on gravitation would consist in one determination of the gravitative attraction between two masses at, say 15°C., and another determination at, say, the temperature of boiling liquid air. But the difficulties of exact determination at ordinary temperatures are not yet overcome, and at any very high or very low temperatures, they would be so much increased that the research seems at present hopeless.

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