A Scheme for Accelerator Classification

1928 ◽  
Vol 1 (3) ◽  
pp. 410-421 ◽  
Author(s):  
R. P. Dinsmore ◽  
W. W. Vogt
Keyword(s):  
Chemical Structure ◽  
Practical Interest ◽  
Chemical Behavior ◽  
The Mind

Abstract MUCH has been written about the constitution and chemical behavior of vulcanization accelerators. Theories have been advanced regarding the mechanism of vulcanization effected with their aid. Yet even the authors of such papers—presumably best qualified to interpret their contents—would hesitate to predict, from chemical structure, many of those features which are of practical interest to the rubber manufacturer. Nevertheless, an increasing number and variety of organic accelerators are being offered on the market, and it is not strange that the mind of the average rubber man is confused by the excess at his command and the conflicting claims of the distributors. In these circumstances it is natural to hesitate to undertake the somewhat formidable task of sorting and classifying. Fortunately, however, it is not necessary to do all the work of classification on a factory scale. Certain laboratory helps are available and can be used to reduce considerably the arduousness of the task. It is believed that an outline of such methods, a discussion of their significance, and a table of results, may be helpful to many in the industry, and it is for this purpose that this paper has been written.

Surface Chemical Behavior of Uranium Metal in Hydrogen Atmosphere Studied by XPS

2003 ◽  
Vol 10 (02n03) ◽  
pp. 325-330 ◽  
Author(s):  
Xiaolin Wang ◽  
Xiaoguo Fu ◽  
Zhengping Zhao
Keyword(s):  
Chemical Structure ◽  
Uranium Oxide ◽  
Main Product ◽  
Profile Analysis ◽  
Hydrogen Atmosphere ◽  
Pure Hydrogen ◽  
Surface Chemical ◽  
Chemical Behavior ◽  
Uranium Metal ◽  
Good Agreement

The surface chemical behavior of clean uranium metal in a hydrogen atmosphere at 80°C and 120°C has been studied using XPS and thermodynamic calculation. The main product is uranium oxide rather than hydride uranium on the uranium surface after the exposure of uranium to extremely pure hydrogen, and the U4f7/2 binding energy of UH3 has been found to be 378.6 ± 0.1 eV. An elevated temperature (120°C) is beneficial to the formation of UH3 species at the same hydrogen exposures. The depth profile analysis of XPS indicates that the chemical structure of the surface layer was UO2/UH3/U after the exposure of hydrogen reached 1.31 × 10-6 L (1 L = 10-6 Torr·s). Results of thermodynamic calculations are in good agreement with the above conclusions.

Reaction of a Thiuram and Sulfur

1955 ◽  
Vol 28 (3) ◽  
pp. 804-807
Author(s):  
G. A. Blokh ◽  
L. P. Sazonova
Keyword(s):  
Chemical Reactions ◽  
Chemical Structure ◽  
Elemental Sulfur ◽  
Practical Interest ◽  
Previous Article ◽  
Tetramethylthiuram Disulfide ◽  
Mercapto Group ◽  
Cable Industry ◽  
Isotopic Method ◽  
Vulcanize Rubber

Abstract In a previous article the occurrence of an intensive interchange between atoms of elemental sulfur when present as vulcanizing agent and the sulfur atoms of the mercapto group of mercaptobenzothiazole as accelerator was shown by the isotopic method, i.e., by the application of tagged atoms of radioactive sulfur. Thus, the existence of a reaction between the accelerator and the vulcanizing agent during the vulcanization of rubber was established. The application of isotopes as tagged atoms is an effective new method of investigating the chemical structure of substances, their reactivities, and the mechanism of chemical reactions in which they take part. This method is being successfully developed in our country, particularly by the work of Brodskii˘ and his pupils. The present study is devoted to the problem of the reaction of tetramethylthiuram disulfide (hereafter called thiuram) and elemental sulfur. Studies in this field are of great scientific and practical interest, since the mechanism of the accelerating action of thiuram is not yet clear. We assume that the chemistry of the reaction is as follows. Thiuram is decomposed during vulcanization, with the formation of a dithiocarbamate and free active sulfur. Because of this, the thiuram can vulcanize rubber without the addition of elemental sulfur to the mixture. Such vulcanizates are particularly widely used in the cable industry.

Derivatives of 2-Mercaptobenzothiazole and Dimethyldithiocarbamic Acid as Vulcanization Accelerators

1959 ◽  
Vol 32 (4) ◽  
pp. 983-991 ◽  
Author(s):  
M. S. Fel'dshteĭn ◽  
I. I. Eĭtingon ◽  
D. M. Pevzner ◽  
N. P. Strel'nikova ◽  
B. A. Dogadkin
Keyword(s):  
Functional Groups ◽  
Chemical Structure ◽  
Practical Interest ◽  
Hydroxyl Group ◽  
Carboxyl Group ◽  
Methyl Radical ◽  
Methyl Derivative ◽  
Great Practical Interest ◽  
Analogous Functional ◽  
Derivatives Of

Abstract 1. We have synthesized and investigated as vulcanization accelerators the derivatives of 2-mercaptobenzothiazole (MBT) in which the thiol hydrogen is replaced by the nonpolar methyl radical, as well as compounds in which methyl hydrogen of the methyl derivative is replaced by various functional groups. 2. It has been shown that methyl-2-thiolbenzothiazole is not an accelerator. The replacement in this compound of one of the methyl hydrogens by a polar hydroxyl group substantially enhances the activity (see, however, editors note in the text). The substitution of hydrogen by a carboxyl group does not increase vulcanizing activity. 3. We have determined that replacement of a methyl hydrogen by an amino radical increases sharply the accelerating activity. The structure obtained as a result of this reaction, benzothiazolyl-2-thiolmethyldiethylamine (BTMA), is of great practical interest as an accelerator. 4. The accelerator BTMA in stocks of natural and SKS rubber gives vulcanizates which are substantially superior in their properties to rubbers cured with MBT, and are practically equal to vulcanizates obtained with sulfenamide accelerators—sulfenamide BT and sulfenamide Z (Santocure). 5. The accelerator BTMA is much cheaper than sulfenamide BT since its production requires much less diethylamine. 6. It has been determined that, just as in the case of 2-mercaptobenzothiazole derivatives, for the derivatives of dimethyldithiocarbamic acid containing analogous functional groups the same results are obtained for the change in activity depending upon the chemical structure of the accelerator.

How Homo economicus lost her mind and how we can revive her

2018 ◽  
Vol 41 ◽  
Author(s):  
Peter DeScioli
Keyword(s):  
Economic Thought ◽  
History Of Economic Thought ◽  
Homo Economicus ◽  
Economic Theories ◽  
Target Article ◽  
History Of ◽  
The Mind ◽  
And Behavior

AbstractThe target article by Boyer & Petersen (B&P) contributes a vital message: that people have folk economic theories that shape their thoughts and behavior in the marketplace. This message is all the more important because, in the history of economic thought, Homo economicus was increasingly stripped of mental capacities. Intuitive theories can help restore the mind of Homo economicus.

Inelastic Electron-Matter Interactions

1978 ◽  
Vol 36 (3) ◽  
pp. 259-267
Author(s):  
J. Silcox
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Chemical Structure ◽  
Inelastic Electron ◽  
Primary Concern ◽  
Unique Probe ◽  
Introductory Paper ◽  
Elastic Processes ◽  
Experimental Level ◽  
Inelastic Processes

In this introductory paper, my primary concern will be in identifying and outlining the various types of inelastic processes resulting from the interaction of electrons with matter. Elastic processes are understood reasonably well at the present experimental level and can be regarded as giving information on spatial arrangements. We need not consider them here. Inelastic processes do contain information of considerable value which reflect the electronic and chemical structure of the sample. In combination with the spatial resolution of the electron microscope, a unique probe of materials is finally emerging (Hillier 1943, Watanabe 1955, Castaing and Henri 1962, Crewe 1966, Wittry, Ferrier and Cosslett 1969, Isaacson and Johnson 1975, Egerton, Rossouw and Whelan 1976, Kokubo and Iwatsuki 1976, Colliex, Cosslett, Leapman and Trebbia 1977). We first review some scattering terminology by way of background and to identify some of the more interesting and significant features of energy loss electrons and then go on to discuss examples of studies of the type of phenomena encountered. Finally we will comment on some of the experimental factors encountered.

Chemical structure of diamond-like carbon thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 710-711
Author(s):  
N.-H. Cho ◽  
K.M. Krishnan ◽  
D.B. Bogy
Keyword(s):  
Electrical Resistivity ◽  
Chemical Structure ◽  
Diamond Like Carbon ◽  
Chemical Structures ◽  
Sputtering Power ◽  
Data Aquisition ◽  
Equilibrium Phases ◽  
Electron Energy Loss ◽  
Power Densities ◽  
Preparation Techniques

Diamond-like carbon (DLC) films have attracted much attention due to their useful properties and applications. These properties are quite variable depending on film preparation techniques and conditions, DLC is a metastable state formed from highly non-equilibrium phases during the condensation of ionized particles. The nature of the films is therefore strongly dependent on their particular chemical structures. In this study, electron energy loss spectroscopy (EELS) was used to investigate how the chemical bonding configurations of DLC films vary as a function of sputtering power densities. The electrical resistivity of the films was determined, and related to their chemical structure.DLC films with a thickness of about 300Å were prepared at 0.1, 1.1, 2.1, and 10.0 watts/cm2, respectively, on NaCl substrates by d.c. magnetron sputtering. EEL spectra were obtained from diamond, graphite, and the films using a JEOL 200 CX electron microscope operating at 200 kV. A Gatan parallel EEL spectrometer and a Kevex data aquisition system were used to analyze the energy distribution of transmitted electrons. The electrical resistivity of the films was measured by the four point probe method.

Metaphors in the Mind

2019 ◽  
Author(s):  
Jeannette Littlemore
Keyword(s):  
The Mind
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