Recent Studies in the Aging of Natural Rubber

1966 ◽  
Vol 39 (5) ◽  
pp. 1565-1576
Author(s):  
C. L. M. Bell ◽  
M. E. Cain ◽  
D. J. Elliott ◽  
B. Saville
Keyword(s):  
Natural Rubber ◽  
Elevated Temperatures ◽  
Research Effort ◽  
The Other ◽  
Detailed Knowledge ◽  
Antioxidant Action ◽  
Aging Resistance ◽  
Increasing Demand ◽  
The One ◽  
Protective Systems

Abstract Natural rubber, when properly compounded, produces articles having an unrivalled combination of properties such as strength, elastic modulus, and resilience. However, in common with the properties of all other polymers, these excellent qualities progressively deteriorate on contact with oxygen, especially at elevated temperatures. The increasing demand for elastomers capable of service at even higher temperatures requires more stringent efforts by research workers for the production of aging-resistant natural rubber, and, in general, two approaches are possible. On the one hand further developments may be sought in the efficiency of the protective systems used. This will necessitate a reasonable understanding of the mechanisms of antioxidant action, and recent reviews have shown the large amount of research effort being applied to this end. On the other hand, modification of the present vulcanization methods to give vulcanizates with inherently greater resistance to aging is a possibility, although progress in this direction requires a detailed knowledge of vulcanization mechanism and vulcanizate structure. The recent work of the Vulcanization Group at NRPRA has shed considerable light on both these aspects of natural rubber chemistry and improved the prospects of success in this direction. In this paper we report results of studies carried out in both the fields described above which have led to the development of technologically acceptable vulcanizates having improved aging resistance.

6. Arrangement of the Metals in an Electro-Frictional Scale

1884 ◽  
Vol 12 ◽  
pp. 412-432
Author(s):  
A. Macfarlane
Keyword(s):  
The Other ◽  
Detailed Knowledge ◽  
The One ◽  
Voltaic Cell ◽  
Made In

While, in recent years, the progress of the science of electricity has been very rapid, few investigations have been made in the old province of frictional electricity. It cannot be doubted, however, that the laws connecting electricity with friction, and with the nature of the substances rubbed, are of great importance; and the acquisition of more detailed knowledge in this department may throw some light on the still imperfect theory of the voltaic cell. Several electricians have expressed an opinion that the development of electricity by friction is only a modification of the development of electricity by contact–that friction is contact in which the number of points which come together is increased by sliding the one substance over the other. But whether friction is a form of contact, or contact a form of friction, or the two co-ordinate to one another, it is interesting to inquire whether the metals can be arranged in an electro-frictional series similar to the electro-contact series; and if so, to observe the relation of the former to the latter.

Conclusion

2019 ◽  
pp. 249-260
Author(s):  
Oliver Morgan
Keyword(s):  
Early Modern ◽  
The Other ◽  
Detailed Knowledge ◽  
Performance Practices ◽  
Early Modern Theatre ◽  
Other Hand ◽  
Turn Taking ◽  
The One

This chapter examines the implications the turn-taking approach for our understanding of early modern performance practices. On the one hand, Shakespearean dialogue is full of subtle effects of timing and sequence that would seem to call for careful rehearsal and a detailed knowledge of the script. On the other hand, everything we know about early modern theatre suggests it was performed with minimal rehearsal by actors who did not necessarily know when, or from where, their next cue would arrive. This apparent mismatch I call ‘the performability gap’. The question is how it can be bridged. The explanation provided by Simon Palfrey and Tiffany Stern—that Shakespeare’s plays are designed to make artistic capital from their own under-rehearsal—does not entirely solve the problem. The second half of the chapter speculates about how else we might account for the gap.

scholarly journals ATLAS Technical Coordination Expert System

2019 ◽  
Vol 214 ◽  
pp. 05035
Author(s):  
Ignacio Asensi Tortajada ◽  
André Rummler ◽  
George Salukvadze ◽  
Carlos Solans Sánchez ◽  
Kendall Reeves
Keyword(s):  
Expert System ◽  
Fault Tree Analysis ◽  
Principal Component ◽  
The Other ◽  
Detailed Knowledge ◽  
Electricity Distribution ◽  
Web Based ◽  
Risk Assessment Models ◽  
Gas Cooling ◽  
The One

When planning an intervention on a complex experiment like ATLAS, the detailed knowledge of the system under intervention and of the interconnection with all the other systems is mandatory. In order to improve the understanding of the parties involved in an intervention, a rule-based expert system has been developed. On the one hand this helps to recognise dependencies that are not always evident and on the other hand it facilitates communication between experts with different backgrounds by translating between vocabularies of specific domains. To simulate an event this tool combines information from different areas such as detector control (DCS) and safety (DSS) systems, gas, cooling, ventilation, and electricity distribution. The inference engine provides a list of the systems impacted by an intervention even if they are connected at a very low level and belong to different domains. It also predicts the probability of failure for each of the components affected by an intervention. Risk assessment models considered are fault tree analysis and principal component analysis. The user interface is a web-based application that uses graphics and text to provide different views of the detector system adapted to the different user needs and to interpret the data

scholarly journals Interpreting a Tatanua Mask

Museum Worlds ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 139-164
Author(s):  
Bruno Haas ◽  
Philipp Schorch ◽  
Michael Mel
Keyword(s):  
Material Culture ◽  
Papua New Guinea ◽  
The Other ◽  
Detailed Knowledge ◽  
Real Word ◽  
Material Thing ◽  
Thick Description ◽  
Complex Response ◽  
Historical Method ◽  
The One

This article introduces the art historical method of functional deixis into the study of material culture in anthropology. Functional deixis begins with a thorough empirical description of communicative effects—visual and embodied—produced by a material thing on the beholder. It then proceeds by tending to a kind of formalisation that enables us, on the one hand, to sharpen our intuitive reaction to the thing and, on the other, to obtain detailed knowledge about the ways material things produce significance. Here, the method is applied to a tatanua mask originating from present-day Papua New Guinea and currently housed at the Grassi Museum für Völkerkunde in Leipzig, Germany. Based on a thick description, we propose an in-depth interpretation of the mask as a complex response to a fundamental injury, articulating a symbolic expression of grief (left side) with an iconic expression overcoming grief (right side) after a passage through a real word expressed through the front of the mask. In doing so, the article offers a tool to study with rather than a text to read off.

scholarly journals On the permeability of transparent screens of extreme tenuity by radiant heat

1833 ◽  
Vol 2 ◽  
pp. 310-311
Keyword(s):  
Thin Film ◽  
Elevated Temperatures ◽  
Ambient Air ◽  
Radiant Heat ◽  
The Other ◽  
Small Aperture ◽  
The One

The author states in this paper, that invisible radiant heat, from sources at elevated temperatures, freely permeates thin transparent screens in the same manner as light; but that as this doctine, established by Profesor Prévost and M. de la Roche has been controverted, he thinks it necessary to demonstrate it by fresh experiments: to this end he covered a small aperture with a film of glass almost iridescent, and keeping it constantly cold, by blowing on it, below the temperature of ambient air, he found that afi air-thermometer on one side of it was not affected by a heated iron ball on the other, if the temperature of the ball was low; but that as this temperature was raised, though not to the point of visible ignition, the effect on the thermometer became Sensible and even considerable. In another experiment, two air-thermometers, having their bulbs transparent, and as thin as possible, were placed equidistant from a heated ball just ceasing to be visible in the dark. The one was clear, the other coated inside with a thin film of pounded charcoal. The latter was most affected.

Effect of Reynolds Number on Deposition in Fuels Flowing Over Heated Surfaces

2013 ◽  
Author(s):  
Clifford Moses
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Chemical Reactions ◽  
Initial Conditions ◽  
The Other ◽  
Heat Transfer Analysis ◽  
Surface Deposition ◽  
Conflicting Evidence ◽  
Increasing Demand ◽  
The One

An increasing demand is being put on the fuel as a heat sink in modern aircraft. In the end, the fuel flows through the atomizer which on the one hand is the hottest part of its thermal history, but on the other hand the most critical for resisting deposition. Most studies have concentrated on the chemistry of deposition, and in recent years there have been modeling efforts. Deposition is really the end product of a coupling between heat transfer to the fuel, chemical reactions to form insoluble gums, followed by the transport of these gums to the surface to form deposits. There is conflicting evidence and theory in the literature concerning the effect of turbulence on deposition, i.e., whether deposition increases or decreases with increasing Reynolds number. This paper demonstrates through a heat transfer analysis that the effect of Reynolds number depends upon the boundary/initial conditions. If the flow is heated from the surface, deposition decreases with increasing Reynolds number; however, for isothermal flows, i.e., preheated, deposition will increase with Reynolds number.

Stress Relaxation during the Thermal Oxidation of Vulcanized Natural Rubber

1960 ◽  
Vol 33 (2) ◽  
pp. 423-432
Author(s):  
J. R. Dunn ◽  
J. Scanlan ◽  
W. F. Watson
Keyword(s):  
Free Radical ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
Thermal Aging ◽  
Elevated Temperatures ◽  
The Other ◽  
Tetramethylthiuram Disulfide ◽  
Oxidative Aging ◽  
Relaxation Measurements ◽  
Cross Links

Abstract The photoinitiated oxidative aging of peroxide vulcanized natural rubber (which contains only carbon-carbon cross-links) was found by stress relaxation measurements to be autocatalytic and to be sensitive to the presence of free radical retarders and catalysts. Similar behavior would be expected in thermal aging. However, earlier work in these laboratories indicated that the thermal aging of peroxide vulcanizates was not autocatalytic. Because of this discrepancy the stress relaxation of peroxide vulcanizates at elevated temperatures has now been reinvestigated and the study has been extended to include also the aging of the other types of networks which are produced on vulcanization by tetramethylthiuram disulfide in the absence of sulfur, by sulfenamide-sulfur, and by sulfur alone.

Vulcanization of Elastomers. 12. Perbunan with Thiuram Monosulfide and Sulfur. I

1959 ◽  
Vol 32 (1) ◽  
pp. 128-138 ◽  
Author(s):  
Walter Scheele ◽  
Horst-Eckart Toussaint
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Temperature Dependence ◽  
Induction Period ◽  
Rate Constants ◽  
The Other ◽  
Tetramethylthiuram Disulfide ◽  
First Order ◽  
The One ◽  
Limiting Value

Abstract The vulcanization of Perbunan 2818 by tetramethylthiuram monsulfide plus sulfur (1 mole monosulfide per gram-atom S) was thoroughly studied. The following results were shown: The limiting value for dithiocarbamate formation is 66 mole per cent of the initial thiuram monosulfide, indicating a two-thirds transformation. The limiting value is practically independent of temperature. The formation of dithiocarbamate can be described as a reaction of the first order. The formation of dithiocarbamate is characterized by an induction period which grows longer with lowering of the temperature, and at 100° C it amounts to about 100 minutes. The rate constants for dithiocarbamate formation were calculated, and it was shown that they were practically the same as those for the vulcanization of Perbunan with tetramethylthiuram disulfide. The activation energies as derived from the temperature dependence of the rate constants for dithiocarbamate formation in the vulcanization of Perbunan by thiuram monosulfide plus sulfur on the one hand and with thiuram disulfide on the other, are only very slightly different and are practically the same as the activation energy for dithiocarbamate formation during the vulcanization of natural rubber with thiuram monosulfide plus sulfur. The results were thoroughly discussed in light of the present conceptions of the course of thiuram vulcanizations.

Die Historische Syntax des Deutschen braucht die Sprachtypologie – und umgekehrt

2015 ◽  
Vol 43 (3) ◽  
Author(s):  
Horst J. Simon
Keyword(s):  
The Other ◽  
Detailed Knowledge ◽  
Linguistic Typology ◽  
Vast Amount ◽  
Other Hand ◽  
Historical Syntax ◽  
General Linguistics ◽  
The One

AbstractIn this paper I try to demonstrate the benefits of interaction between the fields of historical syntax of German on the one hand and linguistic typology on the other hand. Using four examples for each direction, I argue that both fields need each other’s input: German historical syntax can learn to avoid various forms of parochialism, and at the same time it can feed its vast amount of detailed knowledge into discussions of general linguistics.

scholarly journals The Concept of Therapy in Ancient Greek Texts & Dance Practices

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Anna Lazou
Keyword(s):  
Research Effort ◽  
The Other ◽  
Study Group ◽  
Ancient Greek ◽  
Dance Culture ◽  
Greek Culture ◽  
Roman World ◽  
Historical Investigation ◽  
The One

In the context of the research effort of the Ancient Orchesis Study Group to reconstitute the philosophical and wider cultural presuppositions that define the ancient Greek dance culture, from which the Greek-speaking and Roman world was removed, to return with the Renaissance in a new European context, along with the recognition of the basic anthropological, on the one hand, aesthetic, on the other hand, criteria and principles of art and, in particular, of dance expression, we attempt a review of certain concepts like θεραπεία, κάθαρσις, ἔρως and finally δρᾶμα, χορός & ὄρχησις-which stand for characteristic phenomena of ancient Greek culture. This article plays the role of an introduction into the philosophical-historical investigation and understanding of concepts of intrinsic importance in the question about relating philosophy with art and therapy in the ancient world.

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