The Influence of Vulcanization on the Oxidizability of Rubber. Vulcanizing Agents Other Than Sulfur

1939 ◽  
Vol 12 (4) ◽  
pp. 805-825
Author(s):  
Charles Dufraisse ◽  
Jean Le Bras
Keyword(s):  
Benzoyl Peroxide ◽  
Nitro Compounds ◽  
Sulfur Compounds ◽  
Point Of View ◽  
Important Conclusion ◽  
Oxidation Curve ◽  
Final Confirmation ◽  
Very High

Abstract In a previous publication the influence of vulcanization by sulfur and sulfur compounds on the oxidizability of rubber was shown. The most important conclusion was that, in principle, the higher the proportion of combined sulfur, the greater is the oxidizability. However, with very high proportions, the activity of the sulfur changes, i.e., above a certain upper limiting range, the oxidizability tends towards a plateau, whereas below a lower limiting range the oxidation curve passes through a minimum. After having obtained these results, it seemed to be of interest to complete the investigation by studying the effects of vulcanization by agents other than sulfur on oxidizability. In the present work we have examined vulcanization by nitro compounds and peroxides, taking as examples m-dinitrobenzene, trinitrobenzene and benzoyl peroxide. This domain of rubber chemistry has been relatively little explored and certain points either have not received final confirmation or have even led to contrary conclusions. Accordingly it seemed useful to review from a purely objective point of view what has been done on this subject.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

scholarly journals FEBID 3D-Nanoprinting at Low Substrate Temperatures: Pushing the Speed While Keeping the Quality

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1527
Author(s):  
Jakob Hinum-Wagner ◽  
David Kuhness ◽  
Gerald Kothleitner ◽  
Robert Winkler ◽  
Harald Plank
Keyword(s):  
Volume Growth ◽  
Point Of View ◽  
High Fidelity ◽  
Direct Write ◽  
General Picture ◽  
3D Space ◽  
Design Flexibility ◽  
Substrate Temperatures ◽  
Very High ◽  
Comprehensive Discussion

High-fidelity 3D printing of nanoscale objects is an increasing relevant but challenging task. Among the few fabrication techniques, focused electron beam induced deposition (FEBID) has demonstrated its high potential due to its direct-write character, nanoscale capabilities in 3D space and a very high design flexibility. A limitation, however, is the low fabrication speed, which often restricts 3D-FEBID for the fabrication of single objects. In this study, we approach that challenge by reducing the substrate temperatures with a homemade Peltier stage and investigate the effects on Pt based 3D deposits in a temperature range of 5–30 °C. The findings reveal a volume growth rate boost up to a factor of 5.6, while the shape fidelity in 3D space is maintained. From a materials point of view, the internal nanogranular composition is practically unaffected down to 10 °C, followed by a slight grain size increase for even lower temperatures. The study is complemented by a comprehensive discussion about the growth mechanism for a more general picture. The combined findings demonstrate that FEBID on low substrate temperatures is not only much faster, but practically free of drawbacks during high fidelity 3D nanofabrication.

Revolving cards: A financial analysis of the credit repayment and legal implications

2021 ◽  
Vol 39 (2) ◽  
Author(s):  
Salvador Cruz Rambaud ◽  
Salvador Cruz Vargas
Keyword(s):  
Interest Rate ◽  
Credit Card ◽  
Financial Analysis ◽  
Point Of View ◽  
Excessive Amount ◽  
Nominal Interest Rate ◽  
Legal Implications ◽  
Long Duration ◽  
Very High

The framework of this paper is credit card holding by users and consumers, more specifically, the so-called revolving cards. In most cases, the true interest rate applied to a credit is much higher than its nominal interest rate. Usually, this is due to the existence of some fees to be paid by the holder, and to the process of splitting the periods of interest. However, the contracted annual interest rate of revolving cards is very high which, together with the peculiar amortization system, gives rise to an excessive amount of interests. The objective of this paper is to describe and analyze, from a legal and financial point of view, the main characteristics of the credit repayment in revolving cards. We conclude that the complete amortization of the principal needs a long duration and the payment of a high amount of interests.

scholarly journals Back to the Future: Very High-Energy Electrons (VHEEs) and Their Potential Application in Radiation Therapy

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4942
Author(s):  
Maria Grazia Ronga ◽  
Marco Cavallone ◽  
Annalisa Patriarca ◽  
Amelia Maia Leite ◽  
Pierre Loap ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Current Knowledge ◽  
High Energy ◽  
High Dose Rate ◽  
Point Of View ◽  
High Dose ◽  
Dose Rates ◽  
High Energy Electrons ◽  
Very High Energy ◽  
Very High

The development of innovative approaches that would reduce the sensitivity of healthy tissues to irradiation while maintaining the efficacy of the treatment on the tumor is of crucial importance for the progress of the efficacy of radiotherapy. Recent methodological developments and innovations, such as scanned beams, ultra-high dose rates, and very high-energy electrons, which may be simultaneously available on new accelerators, would allow for possible radiobiological advantages of very short pulses of ultra-high dose rate (FLASH) therapy for radiation therapy to be considered. In particular, very high-energy electron (VHEE) radiotherapy, in the energy range of 100 to 250 MeV, first proposed in the 2000s, would be particularly interesting both from a ballistic and biological point of view for the establishment of this new type of irradiation technique. In this review, we examine and summarize the current knowledge on VHEE radiotherapy and provide a synthesis of the studies that have been published on various experimental and simulation works. We will also consider the potential for VHEE therapy to be translated into clinical contexts.

scholarly journals Russia in Greater Mediterranean: New Pacific Eurasian Transition

2021 ◽  
Vol 21 (3) ◽  
pp. 441-458
Author(s):  
Ivan Alexandrovich Chikharev
Keyword(s):  
Political Development ◽  
Mediterranean Region ◽  
Scientific Information ◽  
Point Of View ◽  
Special Role ◽  
Important Conclusion ◽  
Political Transformations ◽  
The Pacific ◽  
History Of ◽  
The Mediterranean

The relevance of the issues raised in the article is related to the active return of Russia to the Mediterranean region, as well as the international political transformations taking place in it. The purpose of the article is to identify the historical foundations, current state and strategic prospects of Russias presence and international influence in the Greater Mediterranean region. The article is based on the methodology of critical geopolitics, historical and comparative approaches, which critically analyze the geopolitical structures of the region, built in the interests of various regional and extra-regional political forces. The historical material of the ancient, medieval, new and modern periods in the history of the macro-region is used, including the poorly studied times of the Mongol presence on the eastern shores of the Mediterranean Sea. Scientific works on the history, geography and international relations in the region, written in the 18th - 19th centuries, as well as modern scientific information on the trends of technological, infrastructural and political development of the Mediterranean region are introduced into scientific circulation. An important element of the article is the thesis about the special role of Russia in the Pacific-European (Eurasian) transit. From the authors point of view, it includes not only the full implementation of Russias transport and logistics potential in the macro-region, but also the transfer of modern technologies, as well as the promotion of the formation of sustainable political regimes. As a result, a conclusion is made about the deep historical foundations of Russias presence and influence in the region, its strategic prospects are justified, and the main directions of our countrys international activities in the Mediterranean region are highlighted. An important conclusion of the article is the thesis about the need for a multilateral balanced approach to solving macro-regional problems.

scholarly journals Common Birds of Chitwan National Park, Nepal

2017 ◽  
Vol 1 (2) ◽  
pp. 19-26
Author(s):  
Parveen Kumar Jha
Keyword(s):  
Protected Area ◽  
National Park ◽  
Bird Species ◽  
Point Of View ◽  
Central Nepal ◽  
South Central ◽  
Tropical Vegetation ◽  
Chitwan National Park ◽  
Common Birds ◽  
Very High

 This research paper gives checklist of common birds of Chitwan National Park, which is a wild-life protected area in south-central Nepal. It covers tropical and sub-tropical vegetation. It is first protected area and includes 932 sq. km. Common birds observed are about 170 belonging to 48 Avian families during 2013-2014. Present investigator has very minutely observed birds in habitat conditions. Bird species were recognized by very high binocular. Birds were thoroughly studied from point of view of Taxonomy. Machans were also erected for observing birds.

scholarly journals Prophetism and Enigma in Zviad Gamsakhurdia’s poetry

2021 ◽  
Author(s):  
Nana Qiria
Keyword(s):  
Point Of View ◽  
The Veil ◽  
Very High

Even a glance at Zviad Gamsakhurdia's work shows that he has experienced a long creative burn, he is extremely strong in worldviews and eternal, unchanging, even strangely calm, but thematically changeable.In his work, the arousal of feelings and the veil of thought are harmoniously combined. When the register of such harmony is very high, elements of prophethood appear in Zviad Gamsakhurdia's work and it must be said that his prophecy is infallible and skillfully placed in the artistic mold. In his poetry there is a skillfully blended vague allegory conveyed with a premeditated intent, something between mediocre openness and obscure, transparent and obscure. It can be boldly said that Zviad Gamsakhurdia is a master of enigmatic poetry.The aim of the research is to critically analyze the poetry of the great Georgian figure, thinker and writer Zviad Gamsakhurdia (from a prophetic and enigmatic point of view).The method is comparative. The merits and weaknesses of Zviad Gamsakhurdia's works can be seen in comparison, more - the first.Research result - Prophecy by Zviad Gamsakhurdia is the biggest secret of life. Both his enigma and prophecy stem from bottomless freedom.

Sulfur Linkage in Vulcanized Rubber. Reaction of Methyl Iodide with Sulfur Compounds

1949 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
M. L. Selker
Keyword(s):  
Methyl Iodide ◽  
Room Temperature ◽  
Sulfur Compounds ◽  
Point Of View ◽  
Secondary Reaction ◽  
Reaction Products ◽  
Sulfide Sulfur ◽  
Vulcanized Rubber ◽  
Allyl Sulfide

Abstract The work described here is an extension of the study of the reaction of methyl iodide with sulfur compounds originally begun with the purpose of using such data in determining the sulfur linkage in vulcanized rubber. A previous paper dealt with the reactions of methyl iodide with propanethiol, propyl sulfide, propyl disulfide, allyl sulfide, and thiophene. This article adds to the list, n-butyl methallyl sulfide, allyl disulfide, allyl tetrasulfide, n-propyl tetrasulfide, and trithiane. The removal of combined sulfur from vulcanized rubber as trimethylsulfonium iodide on treatment with methyl iodide at room temperature was persuasive evidence of the presence of sulfide sulfur linked to allylic type residues. The evidence offered, however, did not constitute exclusive proof because it was not known whether still other types of sulfur linkage would also yield trimethylsulfonium iodide. To shed more light on this question, the sulfur linkages most likely to occur in vulcanizates—the allyl-alkyl monosulfide, diallyl and dialkyl di- and polysulfide—were investigated. The trithiane reaction is of interest mostly from the point of view of the reaction of overcured stocks or secondary reaction products stemming from the original polysulfides. The reactions were carried out using the method described in a previous paper.

The Air-to-air Missile Matra 530

1969 ◽  
Vol 73 (701) ◽  
pp. 449-452
Author(s):  
J. E. Cadoux
Keyword(s):  
Air Force ◽  
High Performance ◽  
First Generation ◽  
Second Generation ◽  
Point Of View ◽  
Ground Control ◽  
Close Link ◽  
Pure Pursuit ◽  
Very High ◽  
Pursuit Curve

The Matra 530 is currently called a second generation air-to-air missile. Indeed the first generation of air-to-air missiles was represented in France by the Nord 5103 which was command-guided, or the Matra 511 which was a semi-active, pure pursuit curve missile. In the second part of the 1950's the requirement was obvious for a sophisticated interception system capable of coping with the high and medium altitude threat represented by heavy and medium bombers. The destruction of this threat required a close link with an interception system composed of ground radars, ground control equipment, sophisticated high performance interceptor aircraft and, as a last link, a very high performance missile. From the French Air Force point of view, the two main characteristics of this missile as the last link of an interceptor system, were first its flexibility in different weather environment and counter measure environment; second, its capability to decrease to the maximum the penetration of the enemy bomber, which meant that the missile should be capable of attacking not only in the rear sector but also in frontal attack and in fact in all sectors around the attacking bomber.

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