Volatility of Antioxidants and Antiozonants II. Effect on Rubber Testing

1965 ◽  
Vol 38 (1) ◽  
pp. 134-139 ◽  
Author(s):  
R. B. Spacht ◽  
W. S. Hollingshead ◽  
H. L. Bullard ◽  
D. C. Wills
Keyword(s):  
Vapor Pressure ◽  
Open Systems ◽  
Accelerated Aging ◽  
Series Data ◽  
Oxygen Absorption ◽  
Accelerated Tests ◽  
Oxygen Bomb ◽  
Closed Systems

Abstract In the first paper of this series data were presented on the volatility and vapor pressure of eight antioxidants. The present work attempts to show how volatility-affects the performance of an antioxidant, particularly in accelerated aging tests. The usual accelerated tests are of two types: those using closed systems such as the air bomb, the oxygen bomb, and oxygen absorption, and those using open systems such as air oven aging and creep.

Expertise as a Form of Knowledge: A Response to Quast

2020 ◽  
Vol 42 (2) ◽  
pp. 431-442
Author(s):  
Steve Fuller
Keyword(s):  
Social Epistemology ◽  
Open Systems ◽  
Epistemic Standard ◽  
Closed Systems ◽  
The Difference

Abstract Christian Quast has presented what he describes as a ‘role-functional’ account of expertise as a form of knowledge that purports to take into account prior discussions within recent analytic social epistemology and allied fields. I argue that his scrupulousness results in a confused version of the role-functional account, which I try to remedy by presenting a ‘clean’ account that clearly distinguishes such an account from what Quast calls a ‘competence-driven’ one. The key point of my account is that ‘competence’ pertains to knowledge in closed systems and ‘expertise’ in open systems. I observe that the invocation of ‘reliability’ as an epistemic standard simply serves to confuse the difference between the competence-driven and role-functional accounts.

6. Such quantities of sand

2014 ◽  
pp. 102-117
Author(s):  
Christopher Hall
Keyword(s):  
Carbon Dioxide ◽  
Circular Economy ◽  
Carbon Dioxide Emissions ◽  
Energy Supply ◽  
Open Systems ◽  
Human History ◽  
Material Flows ◽  
Material Resources ◽  
World Energy ◽  
Closed Systems

‘Such quantities of sand’ looks at sustainability and considers three features of the global materials system that need fixing: carbon dioxide emissions, world energy supply, and finite material resources. All societies, however diverse, are comprehensively and universally dependent on material artefacts. The scale of global material flows is enormous, and now greater than for all of human history. In a finite world, there are limits and so it is wise, on some timescale, to favour a circular economy of closed systems (repair, re-use, recycle) over open systems (extract, make, use, discard). Whatever else we do, it helps if we reduce the rate of flow of materials through the economy (use less, use longer).

Investigating the Mixing Efficiencies of Liquid-to-Liquid Chemical Injection Manifolds for Aquatic Invasive Species Management

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Thomas J. Zolper ◽  
Aaron R. Cupp ◽  
David L. Smith
Keyword(s):  
Invasive Species ◽  
Large Scale ◽  
Open Systems ◽  
Mixing Time ◽  
Water Injection ◽  
The United States ◽  
Aquatic Invasive Species ◽  
Chemical Treatments ◽  
Invasive Organisms ◽  
Closed Systems

Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide) into water can block or kill several invasive organisms and could be a viable option at navigational structures such as lock chambers because chemical infusion would not interfere with vessel passage or lock operation. Chemical treatments near lock structures will require large-scale fluid-mechanic systems and significant energy. Mixing must extend to all stagnation regions within a lock structure to prevent the passage of an invasive fish. This work describes the performance of both wall- and floor-based CO2-infused-water to water injection manifolds targeted for lock structures in terms of mixing time, mixing homogeneity, injection efficiency, and operational power requirements. Both systems have strengths and weaknesses so selection recommendations are given for applications such as open systems and closed systems.

scholarly journals Open Prebiotic Environments Drive Emergent Phenomena and Complex Behavior

Life ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
Nathaniel Wagner ◽  
David Hochberg ◽  
Enrique Peacock-Lopez ◽  
Indrajit Maity ◽  
Gonen Ashkenasy
Keyword(s):  
Open Systems ◽  
Complex Behavior ◽  
Working Models ◽  
Emergent Phenomena ◽  
Systems Chemistry ◽  
Wide Range ◽  
Closed Systems ◽  
Prebiotic Environments ◽  
Far From Equilibrium ◽  
And Function

We have been studying simple prebiotic catalytic replicating networks as prototypes for modeling replication, complexification and Systems Chemistry. While living systems are always open and function far from equilibrium, these prebiotic networks may be open or closed, dynamic or static, divergent or convergent to a steady state. In this paper we review the properties of these simple replicating networks, and show, via four working models, how even though closed systems exhibit a wide range of emergent phenomena, many of the more interesting phenomena leading to complexification and emergence indeed require open systems.

Surface flow of granular materials: model and experiments in heap formation

2001 ◽  
Vol 441 ◽  
pp. 255-264 ◽  
Author(s):  
D. V. KHAKHAR ◽  
ASHISH V. ORPE ◽  
PETER ANDRESÉN ◽  
J. M. OTTINO
Keyword(s):  
Flow Rate ◽  
Open Systems ◽  
Static Friction ◽  
Surface Flow ◽  
Two Dimensional ◽  
Surface Flows ◽  
Industrial Practice ◽  
Natural Systems ◽  
Closed Systems ◽  
Good Agreement

Granular surface flows are important in industrial practice and natural systems, but the understanding of such flows is at present incomplete. We present a combined theoretical and experimental study of quasi-two-dimensional heap formation by pouring particles continuously at a point. Two cases are considered: open systems and closed systems. Experimental results show that the shear rate in the flowing layer is nearly independent of the mass flow rate, and the angle of static friction at the bed–layer interface increases with flow rate. Predictions of the model for the flowing layer thickness and interface angles are in good agreement with experiments.

The Effect of Specimen Thickness on Rate of Artificial Aging

1932 ◽  
Vol 5 (4) ◽  
pp. 698-704
Keyword(s):  
Accelerated Aging ◽  
Mass Action ◽  
Specimen Thickness ◽  
Oxygen Bomb ◽  
Aging Period ◽  
Bomb Test ◽  
Different Types ◽  
Satisfactory Answer ◽  
Theoretical Considerations

Abstract From time to time the question of the effect of thickness on the rate of deterioration of rubber samples subjected to accelerated aging tests, particularly the oxygen-bomb test, is raised. Apparently little experimental work has been done, and no satisfactory answer has yet been given. According to the well-known laws of mass action, the rate of deterioration should slow up with increasing thickness of rubber, and one might expect thin articles to deteriorate further, in a given bomb-aging period, than similar articles of heavier gage. Nevertheless, it is tacitly assumed that variations in thickness have practically no effect—and for small variations this assumption is reasonable considering the oxygen concentration used; or possibly no assumption is made, and the aging tests are just performed mechanically without regard for theoretical considerations and possibilities. The fact that the oxygen-bomb is used largely for comparing the aging quality of similar articles, usually of comparable gage, has doubtless tended to keep the question of the influence of thickness dormant. Again, in the testing of laboratory compounds, most laboratories have standardized on a uniform thickness of cured slabs (0.075″), so that the question of thickness in this type of work does not come into the picture. Occasionally, however, it may be desirable to compare the bomb-aging behavior of articles of quite different types, and when in such cases there is a large difference in thickness, the validity of the comparison may be called in question.

Influence of Exposing Vulcanized Rubber to Light on Its Subsequent Aging in the Dark

1944 ◽  
Vol 17 (1) ◽  
pp. 216-220
Author(s):  
J. R. Scott
Keyword(s):  
Tensile Strength ◽  
Accelerated Aging ◽  
Subsequent Aging ◽  
Oxygen Bomb ◽  
Vulcanized Rubber ◽  
Effect Of Light

Abstract The present experiments confirm the observations of Morgan and Naunton by showing that exposure of vulcanized rubber to light may affect the results of oxygen-bomb aging tests made some days, or perhaps even weeks, afterwards. They show also that a few days' exposure to even diffused daylight may noticeably lower the tensile strength of unaged rubber. With normal, i.e., not transparent, rubbers the effect of light on subsequent aging is small, and indeed does not seem to be noticeable at all in relatively slow aging tests, such as that in the Geer oven. Nevertheless, it is clearly advisable, as a precaution, to avoid unnecessary exposure to light of rubbers that are to be subjected to accelerated aging tests.

Rubber Oxidation and Aging Studies Safe Limits of Sample Thickness

1951 ◽  
Vol 24 (4) ◽  
pp. 999-1016
Author(s):  
George W. Blum ◽  
J. Reid Shelton ◽  
Hugh Winn
Keyword(s):  
Natural Rubber ◽  
Accelerated Aging ◽  
Sample Thickness ◽  
Oxygen Absorption ◽  
Absorption Data ◽  
Synthetic Rubber ◽  
Constant Rate ◽  
Aging Studies ◽  
Safe Limits ◽  
Natural Rubber Vulcanizates

Abstract Safe limits of sample thickness for rubber oxidation and aging studies, such that the chemical reaction rather than the rate of diffusion will be rate-controlling have been investigated for natural-rubber vulcanizates and for four synthetic-rubber types. For studies involving the entire range of oxidation, including the autocatalytic stage of rapid oxygen absorption, the conventional 0.075-inch thickness is frequently not satisfactory for accelerated aging and oxidation studies if it is desired to avoid limitation by diffusion. Only in the GR-S black stock was this thickness found to be satisfactory up to a temperature of 100° C. The other stocks, including natural rubber, Butaprene-NXM, and Neoprene black and gum stocks all require thinner samples to ensure that the observed rate of oxygen absorption is free of limitation by diffusion. A method of calculating the probable limiting value of sample thickness, above which the rate of oxidation in the autocatalytic stage is limited by diffusion, has been developed on the basis of volumetric oxygen absorption data obtained with GR-S. The method has also been applied to natural-rubber vulcanizates and to other synthetic-rubber types to locate the approximate limiting values at various temperatures for oxidation and aging studies which extend into the autocatalytic stage of rapid reaction. The constant-rate period of oxidation is more important from a practical point of view than the autocatalytic stage, since properties are so seriously degraded as to make the rubber of little value before it reaches the final stage of rapid oxidation. Somewhat thicker samples may be used for studies that are confined to the earlier stages of oxidation. A 0.075-inch sample is free of limitation by diffusion in the constant-rate stage in the following cases: GR-S black and gum stocks at 110° C; Hevea black with added antioxidant at 100° C; and uninhibited Hevea black and gum stocks at 60° C. A 0.040-inch sample is satisfactory in this range for: uninhibited Hevea black at 100° and gum at 80° C; Butaprene-NXM black at 100° and gum at 90° C; and Neoprene black and gum stocks at 100° C.

E-Cigarettes: Policy Options and Legal Issues Amidst Uncertainty

2015 ◽  
Vol 43 (S1) ◽  
pp. 23-26 ◽  
Author(s):  
Nancy Kaufman ◽  
Margaret Mahoney
Keyword(s):  
Smoking Cessation ◽  
Propylene Glycol ◽  
Open System ◽  
Closed System ◽  
Open Systems ◽  
Delivery Systems ◽  
Legal Issues ◽  
Policy Options ◽  
Electronic Nicotine Delivery Systems ◽  
Closed Systems

E-cigarettes, sometimes referred to as ENDS (Electronic Nicotine Delivery Systems), include a broad range of products that deliver nicotine via heating and aerosolization of the drug. ENDS come in a variety of forms, but regardless of form generally consist of a solution containing humectant (e.g., propylene glycol or glycerol), flavorings, and usually nicotine (some solutions do not contain nicotine); a battery-powered coil that heats the solution into an aerosol (usually referred to as vapor) in an atomizing chamber; and a mouthpiece through which the user draws the vapor into the mouth and lungs. The devices may be closed systems containing prefilled cartridges, or open systems, where the user manually refills a 1-2 ml. tank with solution. What started as closed-system cigarette-shaped devices marketed as an adjunct for smoking cessation, has transitioned rapidly to literally thousands of hip and funky-designed open-system hookah pens, vape pens, and modifiable devices. For younger people, these forms are the “in” thing, while traditional cigarette-shaped devices are “out.”

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