Chemical Aspects of Vulcanization

1937 ◽  
Vol 10 (2) ◽  
pp. 203-213
Author(s):  
Avan Rossem
Keyword(s):  
Hydrogen Sulfide ◽  
Principal Factor ◽  
Point Of View ◽  
Adsorption Theory ◽  
Chemical Theory ◽  
Chemical Combination ◽  
Opposite Point ◽  
Vulcanization Process

Abstract C. O. Weber was the first to give an elaborate theory of vulcanization. It is well known that he considered the hot vulcanization process as an addition of sulfur to polyprene (C10H16)n on account of the fact that no large amounts of hydrogen sulfide were evolved during the process. Wo. Ostwald, starting from quite the opposite point of view to Weber, put forward in 1910 the adsorption theory of vulcanization, considering it from an entirely colloidal standpoint, the sulfur being adsorbed by the rubber. It soon became clear that vulcanization was much more complex, and that neither of the two theories was able to explain the facts. Since then many investigations have been carried out, and many views, hypotheses, and theories on vulcanization put forward. If one tries to classify these, it becomes apparent that at the present time there is still a chemical theory and a colloidal theory of vulcanization. The chemical theory of vulcanization may be divided in two opposing hypotheses, viz.: (a) Polymerization of the rubber molecule, combination with sulfur being incidental. (b) Chemical combination of sulfur with rubber as the principal factor. To support this statement a few references and quotations from various investigators are given below.

A two-step procedure to identify lexical elements of stance constructions in discourse from political blogs

Corpora ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 379-405 ◽  
Author(s):  
Vasiliki Simaki ◽  
Carita Paradis ◽  
Andreas Kerren
Keyword(s):  
Quantitative Analysis ◽  
Point Of View ◽  
Experimental Procedure ◽  
Political Blogs ◽  
Qualitative Approaches ◽  
Step Procedure ◽  
Category Type ◽  
Opposite Point

The Brexit Blog Corpus (bbc) is a collection of texts extracted from political blogs, which, in a recent study, was annotated according to a cognitive–functional stance framework by two independent annotators (Annotator A and B) using semantic criteria ( Simaki et al., 2017 ). The goal was to label the stance or stances taken based on the overall meaning of a set of utterances. The annotators were not instructed to identify the lexical forms that were used to express the stances. In this study, we make use of those stance-labelled utterances as a springboard to approach stance-taking in text from the opposite point of view, namely from how stance is realised through language. Our aim is to provide a description of the specific lexical elements used to express six stance categories (i.e., contrariety, hypotheticality, necessity, prediction, source of knowledge and uncertainty). To this end, we followed a two-step experimental procedure. First, we performed a quantitative analysis of the stance-labelled utterances in order to identify the lexical realisations of each stance category. Second, we carried out a meta-annotation of the data. Annotator B was instructed to single out the actual lexical forms of the constructions that triggered his semantic stance category decisions. This meta-annotation procedure made it possible for us to sift out the most salient lexical realisations of the constructions of each of the six category types on the basis of the qualitative assessments made by Annotator B. We then compared the results of the quantitative and the qualitative approaches, and we present a list of shared stance expressions for each stance category type.

The Shepherd of Hermas and Christian Life in Rome in the Second Century

1911 ◽  
Vol 4 (1) ◽  
pp. 25-46
Author(s):  
Kirsopp Lake
Keyword(s):  
Early Christianity ◽  
Principal Factor ◽  
Point Of View ◽  
Second Century ◽  
Christian Life ◽  
Son Of Man ◽  
Full Sense ◽  
Second Coming

It was once remarked with much truth that the non-fulfilment of the expectation of the Parousia was the principal factor in the development of early Christianity. This is all the more important, because it was not the custom of the first Christians to speak of the “second” coming—that is a modern point of view—but of the “coming” of the Messiah. To them the Son of Man, Jesus, had come, and the resurrection proved that he was now the Messiah in heaven, but, as Professor Burkitt has recently pointed out, “Son of Man” does not mean “Messiah” in the full sense, but is rather the description given of the predestined and pre-existent Messiah, before he actually came as Messiah in function. The Parousia of the triumphant Messiah whom they expected was as much future for Christians as it was for Jews, and on this point the main difference between the two was that the former believed that they knew who the Messiah was.

Reaction of Elemental Sulfur and Mercaptobenzothiazole

1956 ◽  
Vol 29 (4) ◽  
pp. 1369-1372
Author(s):  
G. A. Blokh ◽  
E. A. Golubkova ◽  
G. P. Miklukhin
Keyword(s):  
Elemental Sulfur ◽  
Active Form ◽  
Chemical Properties ◽  
Intermediate Compound ◽  
Point Of View ◽  
Experimental Fact ◽  
Acceleration Process ◽  
Physico Chemical ◽  
Lower Temperature ◽  
Vulcanization Process

Abstract One of the most important problems in the field of the physics and chemistry of rubber is that of vulcanization. Until now no single theory has been established, which elucidates the complex physico-chemical changes which occur during this process. Still more obscure has been the mechanism of the action of vulcanization accelerators, which, as is well known, not only reduce the time and the temperature of vulcanization, but also influence the physico-mechanical and chemical properties of the rubber. Most investigators have assumed that in the acceleration process a reaction with sulfur converts it to an active form which is capable of bringing about vulcanization at a lower temperature and at a greater rate, than with ordinary elemental sulfur in the absence of an accelerator. This point of view is based on the experimental fact that the vulcanization of rubber by sulfur dioxide and hydrogen sulfide, for example, which form sulfur in the nascent condition, proceeds rapidly even at room temperature. Investigators have also assumed that in the vulcanization process activation of sulfur in the presence of accelerators may occur by different mechanisms. It is possible that the accelerator, reacting with elemental sulfur, forms unstable intermediate compounds, which decompose with liberation of sulfur in an active form. The latter reacts with rubber, and the regenerated accelerator reacts again with elemental sulfur, etc. However, a different process is possible for the activation of elemental sulfur. By this second mechanism the unstable combination of accelerator and sulfur reacts directly with rubber without the formation of active sulfur. Both these mechanisms necessarily assume the formation of intermediate unstable combinations of the accelerator with sulfur. However, direct, experimentally-based demonstrations of such an interaction are lacking in the literature. There exist only theoretical hypotheses concerning the nature of the possible intermediate combination of the accelerator with sulfur. According to Ostromislensky's concepts, further developed by Bedford, such an intermediate compound has the character of a polysulfide. According to Bruni and Romani, this intermediate compound is a disulfide. As is well known, the disulfide theory was placed in doubt by Zaide and Petrov on the basis of data from the vulcanization of rubber in the presence of benzothiazolyl disulfide.

scholarly journals USOS DE LA EVALUACIÓN EN LOS DIFERENTES MOMENTOS DE UNIDADES DIDÁCTICAS COOPERATIVAS

2016 ◽  
Vol 2 (1) ◽  
pp. 517
Author(s):  
Verónica Jiménez Perales ◽  
Mila Naranjo Llanos
Keyword(s):  
Cooperative Learning ◽  
Teaching And Learning ◽  
Point Of View ◽  
Learning Assessment ◽  
Research Focus ◽  
Educational Assistance ◽  
Learning Contexts ◽  
First Approximation ◽  
Opposite Point ◽  
Independent Process

Abstract:ASSESSMENT USES AT DIFFERENT MOMENTS OF COOPERATIVES DIDACTIC UNITSThe traditional conception of learning assessment has been conceived, often, as an independent process of teaching and learning process, but assessment and, more concretely, inclusive assessment has an opposite point of view and it is considerate as an inherent element of this process. This research focus on inclusive assessment in cooperative learning contexts, in schools that implement the CL/LC Program: cooperate to learning, learning to cooperate, developed by the GRAD’s members (Diversity Attention Research Group) of University of Vic. Considering the methodology that propose that program, and the planning and development of didactic units at different moments they can be divided through cooperative structures the hypothesis on the study are linked to a first approximation of the use of evaluation along the process of teaching and learning by teachers. The research results support the hypothesis that implement the CL/LC Program in classrooms should be go according to an inclusive assessment that allow regulate and adjust the educational assistance to students.Keywords : inclusive assessment, learning regulation, cooperative learning,

scholarly journals On the question of speech portraits of political propagandists

2021 ◽  
Vol 8 (3) ◽  
pp. 237-247
Author(s):  
Tatiana A. Milekhina ◽  
Keyword(s):  
Electronic Media ◽  
Family Values ◽  
World Politics ◽  
Point Of View ◽  
Linguistic Features ◽  
Public Speech ◽  
Semantic Categories ◽  
Historical Continuity ◽  
Opposite Point ◽  
Government Propaganda

Based on the analysis of the oral public speech of popular publicists (S. A. Mikheev and I. N. Panarin) working in electronic media and the Internet, the article attempts to characterize the stylistic and semantic originality of modern Russian pro-government propaganda. The dependence of the nature of the linguistic features of propaganda on such factors as the personality of the propagandist, the scope of his activities, and the nature of the transmission is established. It is shown that the personal qualities of Mikheev is conditioned by such features of his speech as emotionality, exceeding the permissible volume level, and careless pronunciation style, while Professor Panarin is characterized by an academic manner of speech with its inherent consideration of the opposite point of view, argumentation, and respect for the audience. It is claimed that the influence of the sphere of activity (Mikheev works in electronic media, such as Evening with Vladimir Solovyov, the radio program Iron Logic, Panarin conducts an analytical program Igor Panarin. World Politics on the YouTube channel) is found in taking into account the composition and request of the audience to which the propaganda is directed. Television discussion allows rudeness, verbal aggression, reduced vocabulary, political banter, logic of the absurd, direct insults, and threats to opponents. Analytical transmission involves the strategic forecasting of events filled with the metaphysics of propaganda, the creation of mythologies, the use of allegories, and hints. It is proved that despite the almost opposite stylistic format, the propaganda discourse of Mikheev and Panarina is characterized by common dominant semantic categories, such as traditional family values, religiosity, conservatism, protection of the interests of the state, humanistic maximalism, and the historical continuity of Russia.

Six Technological Innovations That Changed English Language Teaching

2019 ◽  
Vol 8 (1) ◽  
pp. 30-38
Author(s):  
Bekešová Jana ◽  
Romanová Iveta
Keyword(s):  
Teaching And Learning ◽  
English Language ◽  
Language Teaching ◽  
English Teachers ◽  
Point Of View ◽  
English Language Teaching ◽  
Technological Innovations ◽  
Opposite Point ◽  
The Difference ◽  
Learning English

Abstract The paper focuses on six technological innovations which have influenced English language teaching and learning. Their potential is analysed and the way suggested how they could be creatively used. In the research part, authors introduce the most popular ones among English teachers and present those they would like to apply within the lessons. Being able to analyse the opposite point of view as well, small number of English students were asked which of these technological tools their English teachers use the most and on the other hand, would like to experience when learning English. In addition, we compare the difference in their choice when teaching and learning English at primary and secondary school.

“The devil is in the details”: S.M. Kirov’s emergent leadership and its elimination

2020 ◽  
Vol 2020 (12-1) ◽  
pp. 189-200
Author(s):  
Sergey Kislitsyn
Keyword(s):  
First Generation ◽  
Personal Characteristics ◽  
Point Of View ◽  
Political Elite ◽  
Emergent Leadership ◽  
Psychological Review ◽  
Initial Stage ◽  
Opposite Point ◽  
Counter Process ◽  
The Devil

On the basis of historiography, a comparative socio -psychological review of political biographies and personal characteristics of Stalin and Kirov is carried out. A number of new sources were used: the correspondence of the Bolsheviks, the stenotech of Trotsky’s counter-process, and journalistic investigations. The system of indirect various data presented in favor of the version of Stalin’s participation in the organization of the murder of Kirov and qualitatively and quantitatively clearly outweighs the set of indirect arguments from the opposite point of view. The removal of Kirov was the initial stage of the forced rotation of the first generation of the Bolshevik political elite. The crime was a stain of Stalin, which eventually killed him mentally.

A TEOLOGIA CRISTÃ EM FACE DA FILOSOFIA CONTEMPORÂNEA

2010 ◽  
Vol 28 (92) ◽  
pp. 359
Author(s):  
Lorenz B. Puntel
Keyword(s):  
Point Of View ◽  
Fundamental Unit ◽  
Christian Theology ◽  
Contemporary Philosophy ◽  
Philosophical Work ◽  
Christian Philosophy ◽  
Opposite Point ◽  
Theoretical Dimension

Este artigo examina os conceitos de teologia cristã e de filosofia contemporânea, mostra como se pode conceber uma unidade fundamental entre o que se costuma chamar de “teologia cristã” e “filosofia (cristã)” — filosofia e teologia representam duas perspectivas diferentes mas complementares com respeito a uma única dimensão teórica; as duas perspectivas abrangem os mesmos conteúdos, apenas vistos e articulados de dois pontos de vista exatamente opostos, mas ao mesmo tempo absolutamente complementares — e aponta para algumas exigências metódicas, conceituais e teóricas indispensáveis para o trabalho teológico (e filosófico).Abstract: This article examines the concepts of Christian theology and of contemporary philosophy. It shows how one can conceive a fundamental unit among defined Christian theology Christian philosophy. Philosophy and Theology represent two different but complementary perspectives with regard to an only theoretical dimension The two perspectives embrace the same contents, just seen and articulated of two exactly opposite point of view, but at the same time absolutely complementary. In addition, it points out to some indispensable methodical, conceptual and theoretical demands for the theological and philosophical work. 

Stoichiometry of Vulcanization with Sulfur

1951 ◽  
Vol 24 (4) ◽  
pp. 878-893
Author(s):  
R. L. Zapp ◽  
R. H. Decker ◽  
Margaret S. Dyroff ◽  
Harriet A. Rayner
Keyword(s):  
Physical Properties ◽  
Polymer Networks ◽  
Diazo Compounds ◽  
Polymerization Process ◽  
Cross Linking ◽  
High Chemical ◽  
Chemical Combination ◽  
Cross Linkage ◽  
Vulcanization Process ◽  
Butadiene Styrene

Abstract In the study of vulcanization with natural rubber and other polymers of relatively high chemical unsaturation, it has always been difficult to represent the vulcanization process molecularly because of the complexity of the sulfur-polymer reactions. To circumvent this difficulty, reactions of small olefin molecules with sulfur have often been studied to obtain this molecular insight. Some investigators have resorted to cross-linking the polymer with agents other than sulfur to characterize the network for comparisons with physical properties. By cross-linking rubber molecules with diazo compounds, which add quantitatively to the olefin bond, Flory has characterized the network so formed in a molecular manner and correlated the degree of cross-linking with physical properties. When correlating physical properties with degree of cross-linking in butadiene-styrene polymers, others have cross-linked the polymer as a final step in the polymerization process. When a polymer of low unsaturation is used, many of the experimental difficulties are eliminated or reduced, and a more reliable stoichiometric picture of the phenomenon can be obtained. The emphasis in this work is placed on the chemical combination of sulfur with polymer rather than on any correlation with physical properties, and rests upon the “dimensions” of swollen polymer networks as related to total combined and organically combined sulfur. The low unsaturation of Butyl rubber makes it possible to satisfy all the potential points of cross-linkage while still possessing a network that is soft and elastic. In actual practice, there probably is a small percentage of the reactive sites or points of unsaturation disposed in such a way that they cannot approach an active site in another molecule. Experimentally, however, one can obtain a “maximum” state of vulcanization where further vulcanization time or additional sulfur and accelerator do not contribute further to additional cross-linkage. This feature is utilized in the present investigations.

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