Isothermal and Adiabatic Stress-Strain Curves of Vulcanized Rubber

1939 ◽  
Vol 12 (1) ◽  
pp. 64-70 ◽  
Author(s):  
V. Hauk ◽  
W. Neumann
Keyword(s):  
Chemical Nature ◽  
Absolute Temperature ◽  
Strain Diagram ◽  
Stress Strain ◽  
Isothermal Conditions ◽  
Adiabatic Conditions ◽  
Vulcanized Rubber ◽  
The Subject ◽  
The Difference ◽  
Thermodynamic Interpretation

Abstract The stress-strain diagram of rubber has been the subject of a large number of investigations, including those of Röntgen, Gough, and Joule in the nineteenth century, those on isothermal phenomena by Meyer and Ferri, and Wiegand and Snyder, and most recently those on adiabatic phenomena of Ornstein, Eymers, and Wouda. The investigations of Meyer and Ferri are concerned chiefly with the dependence of the stress-strain phenomena on the temperature, and they confirm experimentally the hypothesis that within a certain range of temperature and with highly vulcanized samples, the stress is proportional to the absolute temperature, i. e., S=aT+b. At lower states of vulcanization this proportionality does not hold true. The work of Ornstein and his collaborators, which is frequently cited in the literature, is concerned with the phenomena which take place when raw rubber and weakly vulcanized rubber are stretched adiabatically; that of Wiegand and Snyder is concerned chiefly with a thermodynamic interpretation of stress-strain curves obtained experimentally. Now in spite of the fact that stress-strain curves of rubber have been determined so frequently, particularly under isothermal conditions, these measurements are for the most part of limited value, since the chemical nature of the types of rubber employed is not described definitely. Then again in most cases little attention was paid to the difference between isothermal and adiabatic stretching. In view of these facts, it seemed desirable to throw further light on the problem by obtaining stress-strain curves of one particular well-defined material. The object of the present work was then: 1. To obtain true isothermal stress-strain curves as a function of the degree of vulcanization and as a function of the temperature, and thus to study stresses as a function of temperature. 2. To obtain data on the same vulcanizates under adiabatic conditions. 3. To compare the stress-strain results under isothermal conditions with those under adiabatic conditions.

The Behavior of Raw Rubber When Stretched Isothermally

1938 ◽  
Vol 11 (4) ◽  
pp. 647-652 ◽  
Author(s):  
H. Hintenberger ◽  
W. Neumann
Keyword(s):  
Room Temperature ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Steep Ascent ◽  
Flow Effect ◽  
Vulcanized Rubber ◽  
Flow Phenomena ◽  
Entropy Effect ◽  
The Subject

Abstract The S-shaped form of the stress-strain curve of rubber is today explained in a quite satisfactory way. In the first part of the curve, i. e., the gradual ascent, work must be expended because of the van der Waals forces of attraction of the molecules; in the second part, i. e., the steep ascent, the elasticity is chiefly an entropy effect, which is finally exceeded by crystallization phenomena. The phenomenon of crystallization itself has been the subject of extensive investigations, but in most cases vulcanized rubber has been employed, and because of the various accelerators and fillers which the rubber has contained, the products have been rather ill-defined. It is evident that the phenomena involved in crystallization would be much more clearly defined if the substance under investigation were to be in a higher state of purity. If experiments are carried out with raw rubber, a flow effect is added to the various other phenomena. As a result of this flow effect, Rosbaud and Schmidt, and Hauser and Rosbaud as well, found that the stress-strain curve depends on the rate of elongation at very low extensions, with a greater stiffness at high rates of elongation. As found recently by Kirsch, there is no evidence of any flow phenomena in vulcanized rubber at room temperature. Most investigations have been so carried out that the stress has been measured at a definite elongation. It was therefore of interest to determine the elongation at constant stress, and the changes in this relation with time and with temperature, of various types of raw rubber.

Characteristic Properties of Rubber at Low Temperatures. A Discussion of the Stress-Strain Curves of Vulcanized Rubber at Low Temperatures

1934 ◽  
Vol 7 (4) ◽  
pp. 610-617 ◽  
Author(s):  
Takeo Fujiwara ◽  
Toramatsu Tanaka
Keyword(s):  
Physical Properties ◽  
Low Temperatures ◽  
External Heat ◽  
Point Of View ◽  
Special Importance ◽  
Stress Strain ◽  
Experimental Proof ◽  
Vulcanized Rubber ◽  
The Subject ◽  
Two Phases

Abstract The hardening of rubber at low temperatures is one of the well-known physical characteristics of rubber. The loss of elasticity of raw rubber by hardening at 0° to 10° C., its turning to the consistency of glass, and its fragility at −19° C. when cooled with liquid air, and its fibering when stretched to 60–70 per cent previous to breaking, give an experimental proof of the theory of the structure of rubber molecules. Vulcanization makes raw rubber physically less sensitive to heat and to low temperatures, and is of great significance, because it enables vulcanized rubber to be used around −30° C. without losing its elasticity. The effect of external heat on the physical properties, especially on the stress-strain relations, of vulcanized rubber has been discussed mainly for temperatures from −10° to +100° C., and only two papers deal with temperatures from −30° to −60° or −70° C. (cf. Le Blanc and Kröger, Kolloid Z., 37, 205 (1925); Tener, Kingsbury and Holt, Bureau of Standards Technologic Papers Vol. 22, No. 364). Of special importance are a means of recognizing changes m the physical properties (phenomenon of freezing-hard ness) of vulcanized rubber at −30° to −60° or −70° C., and the practical value of such information. Though there is a contradiction in the fundamental meaning of the “cold resistant theory” of rubber, investigations of the two phases of the subject may throw some light on practical problems and widen the scientific point of view.

Unified deformation behavior of polymer foams

2020 ◽  
pp. 14-19
Author(s):  
Maxim Arzhakov ◽  
Pavel Yakovlev ◽  
Alexander Lopatkin
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Chemical Nature ◽  
General Pattern ◽  
Strain Diagram ◽  
Polymer Foams ◽  
Mechanical Parameters ◽  
Yield Strain ◽  
Stress Strain ◽  
Temperature Regimes

The factors which control mechanical properties of plastic polymer foams were systematized. The procedure to unify their deformation behavior up to the strain not above yield strain was proposed. The general features of the deformation behavior of polymer foams were discussed in terms of the unified stress-strain diagram and unified ratios between mechanical parameters of the materials, which are not dependent on chemical nature of polymers and the structure of the foams, as well as on time-temperature regimes of deformation. The general pattern of deformation was shown for organic and inorganic plastic bodies.

Learning Language Levels in Students Accurate with a History Academic Achievement History

2017 ◽  
Vol 1 (2) ◽  
pp. 137
Author(s):  
Noorlela Binti Noordin ◽  
Abdul Razaq Ahmad ◽  
Anuar Ahmad
Keyword(s):  
Academic Achievement ◽  
Statistical Inference ◽  
Quantitative Data ◽  
Quantitative Methods ◽  
Descriptive Statistics ◽  
Language Test ◽  
The Subject ◽  
The Difference ◽  
Learning Language ◽  
The Relationship

This study was aimed to evaluate the Malay proficiency among students in Form Two especially non-Malay students and its relationship to academic achievement History. To achieve the purpose of the study there are two objectives, the first is to look at the difference between mean of Malay Language test influences min of academic achievement of History subject among non-Malay students in Form Two and the second is the relationship between the level of Malay proficiency and their academic achievement for History. This study used quantitative methods, which involved 100 people of Form Two non-Malay students in one of the schools in Klang, Selangor. This study used quantitative data were analyzed using descriptive statistics and statistical inference with IBM SPSS Statistics v22 software. This study found that there was a relationship between the proficiency of Malay language among non-Malay students with achievements in the subject of History. The implications of this study are discussed in this article.

The Idea of a Meaningful Synthesis of Marxist and Non-Marxist Systems of Political Economy as a Mirror of Intellectual Turmoil (About V.T. Ryazanov’s Book «Modern Political Economy: Prospects of Neo-Marxist Synthesis»)

2019 ◽  
pp. 74-98
Author(s):  
A.B. Lyubinin
Keyword(s):  
Economic Theory ◽  
Political Economy ◽  
Economic Status ◽  
Economic Science ◽  
Objective Reality ◽  
Commodity Production ◽  
Subjective Assessments ◽  
The Subject ◽  
The Difference ◽  
Political Economic

Review of the monograph indicated in the subtitle V.T. Ryazanov. The reviewer is critical of the position of the author of the book, believing that it is possible and even necessary (to increase the effectiveness of General economic theory and bring it closer to practice) substantial (and not just formal-conventional) synthesis of the Marxist system of political economy with its non-Marxist systems. The article emphasizes the difference between the subject and the method of the classical, including Marxist, school of political economy with its characteristic objective perception of the subject from the neoclassical school with its reduction of objective reality to subjective assessments; this excludes their meaningful synthesis as part of a single «modern political economy». V.T. Ryazanov’s interpretation of commodity production in the economic system of «Capital» of K. Marx as a purely mental abstraction, in fact — a fiction, myth is also counter-argued. On the issue of identification of the discipline «national economy», the reviewer, unlike the author of the book, takes the position that it is a concrete economic science that does not have a political economic status.

Rhythm

2018 ◽  
Author(s):  
Lexi Eikelboom
Keyword(s):  
Social Sciences ◽  
Twentieth Century ◽  
Human Existence ◽  
Embodied Experience ◽  
Giorgio Agamben ◽  
The Social ◽  
Contemporary Philosopher ◽  
The Subject ◽  
The Difference ◽  
Theoretical Category

This book argues that, as a pervasive dimension of human existence with theological implications, rhythm ought to be considered a category of theological significance. Philosophers and theologians have drawn on rhythm—patterned movements of repetition and variation—to describe reality, however, the ways in which rhythm is used and understood differ based on a variety of metaphysical commitments with varying theological implications. This book brings those implications into the open, using resources from phenomenology, prosody, and the social sciences to analyse and evaluate uses of rhythm in metaphysical and theological accounts of reality. The analysis relies on a distinction from prosody between a synchronic approach to rhythm—observing the whole at once and considering how various dimensions of a rhythm hold together harmoniously—and a diachronic approach—focusing on the ways in which time unfolds as the subject experiences it. The text engages with the twentieth-century Jesuit theologian Erich Przywara alongside thinkers as diverse as Augustine and the contemporary philosopher Giorgio Agamben, and proposes an approach to rhythm that serves the concerns of theological conversation. It demonstrates the difference that including rhythm in theological conversation makes to how we think about questions such as “what is creation?” and “what is the nature of the God–creature relationship?” from the perspective of rhythm. As a theoretical category, capable of expressing metaphysical commitments, yet shaped by the cultural rhythms in which those expressing such commitments are embedded, rhythm is particularly significant for theology as a phenomenon through which culture and embodied experience influence doctrine.

On Thick-Walled Cylinder Under Internal Pressure

2003 ◽  
Vol 125 (3) ◽  
pp. 267-273 ◽  
Author(s):  
W. Zhao ◽  
R. Seshadri ◽  
R. N. Dubey
Keyword(s):  
Internal Pressure ◽  
Strain Curve ◽  
Stress Strain ◽  
Piecewise Linearization ◽  
Elastic Plastic ◽  
Plastic Cylinder ◽  
Parametric Functions ◽  
The Difference ◽  
New Formulation ◽  
Walled Cylinder

A technique for elastic-plastic analysis of a thick-walled elastic-plastic cylinder under internal pressure is proposed. It involves two parametric functions and piecewise linearization of the stress-strain curve. A deformation type of relationship is combined with Hooke’s law in such a way that stress-strain law has the same form in all linear segments, but each segment involves different material parameters. Elastic values are used to describe elastic part of deformation during loading and also during unloading. The technique involves the use of deformed geometry to satisfy the boundary and other relevant conditions. The value of strain energy required for deformation is found to depend on whether initial or final geometry is used to satisfy the boundary conditions. In the case of low work-hardening solid, the difference is significant and cannot be ignored. As well, it is shown that the new formulation is appropriate for elastic-plastic fracture calculations.

scholarly journals The enzymes of B. coli communis . Part V.—(a) anaerobic growth followed by anaerobic and aerobic fermentation. (b) the effects of aeration during the fermentation

1921 ◽  
Vol 92 (644) ◽  
pp. 135-150
Keyword(s):  
Anaerobic Growth ◽  
Aerobic Growth ◽  
Aerobic Fermentation ◽  
The Subject ◽  
The Difference ◽  
Effect Of Oxygen ◽  
Present Section ◽  
Ferment Glucose

In the present communications the effect of oxygen upon the fermentation of glucose and upon the growth of the bacteria, in so far as this affects fermentation, is considered. To this end the organisms have been grown both aerobically and anaerobically, and subsequently made to ferment glucose, both aerobically and anaerobically, with the object of comparing the products of decomposition in the two cases. There are clearly two problems : firstly, the effect of exposure to oxygen during growth upon the subsequent fermentation, whether aerobic or anaerobic, and, secondly, the effect of oxygen admitted during the fermentation. The first question relates to the part played by oxygen in the formation of enzymes, the second to the part played by oxygen in their action on carbohydrates. The first question is considered, though in but a preliminary way, in Section A, the second, more fully, in Section B. Section A. Object of the Experiments . Two results were aimed at in these experiments. Firstly, to compare the products of fermentation of glucose anaerobically, after anaerobic growth, with the products of fermentation anaerobically after previous growth aerobically. And, secondly, to obtain information as to the effect of introducing oxygen during the fermentation itself. This latter consideration, however, though brought to notice by these experiments, is considered only incidentally here because it forms the subject of Section B. In the present section we wish to direct attention particularly to those differences which exist between the fermentation after anaerobic and aerobic growth, not upon the effect of aeration during the fermentation. To point out the difference which previous growth aerobically or anaerobically has made, several analyses from previous experiments are included in Table IV side by side with the completely anaerobic experiments of Tables I, II, and III.

Violencia de (L) género: “Hacia una sofística de la materialidad de los cuerpos” / Violent gender: “To a sophistry of the materiality of bodies”

2016 ◽  
Vol 5 (09) ◽  
pp. 83-97
Author(s):  
Claudio Reyes Lozano
Keyword(s):  
Gender Studies ◽  
Material Body ◽  
Aristotelian Logic ◽  
Political Position ◽  
Basic Assumptions ◽  
The Subject ◽  
The Difference ◽  
And Gender ◽  
Critical Gender Studies

Los estudios críticos de género sustancialistas desconocen su posición teórico-política en el momento de explayar algunas de sus hipótesis fundamentales. El presente estudio intenta dar cuenta de las consecuencias éticas que asume llevar hasta el final algunas de estas posiciones teóricas. Advertimos así que obras fundamentales de estos estudios se apropian con claridad, y sin saberlo, de una lógica aristotélica para tratar la asunción material del cuerpo, el sujeto y el género ¿Qué encontramos específicamente en esta lógica? Esta última se caracteriza por tener su raíz en una ontología inamovible, en donde cualquier intento de desbaratar el “ser” tiene como respuesta inmediata la exclusión violenta de la diferencia: concretamente observamos esto, dialogando tanto con colegas como legos, en la “violencia académica” pero también en la “violencia cotidiana” ¿Cómo salir del cierre metafísico que ha mantenido durante décadas la violencia y exclusión de aquello que se generó en primera instancia, paradójicamente, como argumentación de tolerancia y emancipación? Pensamos que deconstruyendo el discurso de género aristotélico podremos vislumbrar nuevas hipótesis y posiciones ético-políticas que no recurran, para validarse, a la exclusión violenta de nuevos cuerpos-sujetos-géneros. Some critical gender studies do not know their theoretical and political position at the time to developing some of their basic assumptions. This study attempts to explain the ethical consequences that lead to the end some of these theoretical positions. We realize that fundamental works of these studies clearly appropriating, and without knowing it, an aristotelian logic to justify the assumption of material body, the subject and gender. What specifically found in this logic? It is characterized to found on an immovable ontology, where any attempt to disrupt the “being” has as an immediate violent response to exclude the difference: specifically we observe this, dialoguing with colleagues and laymen, in the “academic violence” but also “everyday violence”. How to get out of the metaphysical closure that maintained for decades the violence and exclusion of what is generated in the first place, paradoxically, as argument of tolerance and emancipation? We think deconstructing the aristotelian discourse of gender can warn new hypotheses and ethical positions that not based, to validate, on a violent exclusion of new bodies-subject-genres positions.

Sign in / Sign up

Export Citation Format

Share Document