Processing Ease and Rubber—Carbon-Black Interaction

1988 ◽  
Vol 61 (2) ◽  
pp. 362-376 ◽  
Author(s):  
N. Nakajima ◽  
R. A. Miller
Keyword(s):  
Carbon Black ◽  
Ethyl Acrylate ◽  
Dynamic Mechanical Properties ◽  
Strain Measurements ◽  
Carbon Blacks ◽  
Two Samples ◽  
History Of ◽  
The Difference ◽  
Particle Size And Structure ◽  
Size And Structure

Abstract Two samples of poly(ethyl acrylate) rubber, different in their mill processability and their manner of accepting carbon black were examined. This is a case history of how we differentiated Theological behavior of gum elastomers and how we characterized the rubber—carbon-black interaction in the compound. For the former objective, the dynamic mechanical properties were measured over the temperature range of interest. This information was used to interpret the difference in mill processability. For the latter objective, several carbon blacks in different particle size and structure were compounded with these samples. The effect of the different carbon blacks on these elastomers was examined with tensile stress-strain measurements. At least a part of the differences in behavior could be interpreted as the differences in the interaction between rubber and carbon black.

Nature of Network, Carbon-Black-Rubber Interaction and Heat Aging of Polyethylacrylate Vulcanizates

1989 ◽  
Vol 62 (2) ◽  
pp. 357-366 ◽  
Author(s):  
N. Nakajima ◽  
R. A. Miller
Keyword(s):  
Carbon Black ◽  
Chemical Nature ◽  
Tensile Modulus ◽  
Large Strains ◽  
Molecular Architecture ◽  
Strain Measurements ◽  
Small Strains ◽  
Two Samples ◽  
Weight One ◽  
The Difference

Abstract Two commercial polyethylacrylate elastomers, having about 50 Mooney Index were selected. They were compounded with 50 parts of N330 carbon black per 100 parts of rubber by weight. One sample having epoxide (EP) crosslinking sites was crosslinked with ammoniumbenzoate. The other having double-bonds by copolymerizing with ethylidene norbornene (ENB) was crosslinked with a sulfur system. The vulcanizates were oven aged at 175°C for 70 h. Tensile stress-strain measurements were performed with the gum rubbers, uncured compounds, unaged vulcanizates, and heat-aged vulcanizates. The data presented as tensile modulus—strain curves revealed the following: at all strain levels, the moduli of ENB gum samples were lower than those of EP gums. After compounding with carbon black, the moduli of two samples became very similar. This indicates that ENB has more affinity with carbon black than EP has. The vulcanizates of two samples has matching moduli at 10% strain but a difference in network structure, since the molecular architecture of the gum rubbers were very different. After heat aging, moduli at small strains increased significantly but not at large strains. The increases were very similar for both samples. The heat-aging characteristics may be very similar for both samples, in spite of the difference in the chemical nature of the crosslinks.

scholarly journals Variations between two 24-hour urine collections in patients

2013 ◽  
Vol 6 (1) ◽  
pp. 30 ◽  
Author(s):  
Madhur Nayan ◽  
Mohamed A. Elkoushy ◽  
Sero Andonian
Keyword(s):  
Clinical Decision Making ◽  
Clinical Decision ◽  
Metabolic Evaluation ◽  
Normal Limits ◽  
A Value ◽  
Two Samples ◽  
History Of ◽  
The Absolute ◽  
The Difference ◽  
Urinary Parameters

Introduction: The current Canadian Urological Association (CUA)guideline recommends two 24-hour urine collections in the metabolic evaluation for patients with urolithiasis. The aim of the present study was to compare two consecutive 24-hour urine collections in patients with a history of urolithiasis presenting to a tertiary stone clinic.Methods: We retrospectively reviewed 188 patients who had two24-hour collections upon presentation between January 2010 and December 2010. Samples were collected on consecutive days and examined for the following 11 urinary parameters: volume, creatinine, sodium, calcium, uric acid, citrate, oxalate, potassium, phosphorous, magnesium and urea nitrogen. For each parameter, the absolute value of the difference between the two samples rather than the direct difference was compared with zero. Similarly, the percent difference between samples was calculated for each parameter.Results: The means of the absolute differences between the twosamples were significantly different for all 11 urinary parameters(p < 0.0001). The percent differences for all urinary parametersranged from 20.5% to 34.2%. Furthermore, 17.1% to 47.6% ofpatients had a change from a value within normal limits to anabnormal value, or vice-versa. Significance was maintained when patients with incomplete or over-collections were excluded.Conclusions: Significant variations among the two 24-hour urinecollections were observed in all of the 11 urinary parameters analyzed. This variation may change clinical decision-making in up to 47.6% of patients if only a single 24-hour urine collection is obtained. The present study supports the CUA guideline of performing two 24-hour urine collections.

Experiences with a Direct Accelerator-Adsorption Test

1932 ◽  
Vol 5 (3) ◽  
pp. 429-441
Author(s):  
F. H. Amon ◽  
R. K. Estelow
Keyword(s):  
Carbon Black ◽  
Adsorption Properties ◽  
Dilute Solution ◽  
Carbon Blacks ◽  
Separate Control ◽  
History Of ◽  
Or History

Abstract A method for determining the accelerator adsorption properties of carbon blacks is described. This method is novel in that an extremely dilute solution of diphenylguanidine in benzene is employed. Application of the test to a large number of carbon blacks has revealed its practical value as a measure of those variations in adsorption properties which are of teal significance to the rubber manufacturer. The method has been employed in several separate control laboratories and it has been found to be of distinct value in indicating quality of production. Since the results can be interpreted without knowledge of source or history of the particular carbon black being tested, the test can be employed for control purposes by the rubber manufacturer as well as by the carbon black manufacturer.

Effects of particle size and structure of carbon blacks on the abrasion of filled elastomer compounds

2007 ◽  
Vol 42 (20) ◽  
pp. 8391-8399 ◽  
Author(s):  
Chang Kook Hong ◽  
Hyunsung Kim ◽  
Changseok Ryu ◽  
Changwoon Nah ◽  
Yang-il Huh ◽  
...  
Keyword(s):  
Particle Size ◽  
Carbon Blacks ◽  
Filled Elastomer ◽  
Particle Size And Structure ◽  
Size And Structure

Determination of Carbon Black Type in Filled Rubber Vulcanizates

1967 ◽  
Vol 40 (5) ◽  
pp. 1323-1329 ◽  
Author(s):  
Lester G. Nabors ◽  
Merton L. Studebaker
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Filled Rubber ◽  
Vacuum Pyrolysis ◽  
Acid Washing ◽  
Analogous Data ◽  
Particle Size And Structure ◽  
Qualitative Analyses ◽  
Size And Structure

Abstract A system of analysis has been described which permits determining the type of rubber grade carbon black in a vulcanizate. The carbon black is removed from the vulcanizate by vacuum pyrolysis at 850° C and its reflectance after acid washing and compression at 15,000 psi and apparent specific volume at 703 psi are determined. These measurements permit estimation of particle size and “structure.” Supplementary analyses are required for channel blacks. The procedure is most precise when the analytical values are compared with analogous data obtained from carbon blacks of known properties when removed by the same procedure from similar vulcanizates. As in all qualitative analyses, the more information which is available to the analyst, the more reliably he is able to interpret his results.

Reactions of Polymers in Bulk. II. Influence of Crosslink Density on the Mechanical Deformation Properties of Filled Vulcanizates

1962 ◽  
Vol 35 (3) ◽  
pp. 572-580
Author(s):  
J. Janacek
Keyword(s):  
Carbon Black ◽  
Crosslink Density ◽  
Mechanical Deformation ◽  
Physical Effect ◽  
Carbon Blacks ◽  
Deformation Properties ◽  
The Difference

Abstract The mechanical deformation properties as characterized by the modulus at different deformation, hardness and rebound elasticity, were observed in elastomers filled with different carbon-black concentrations referred to the concentration of the effective chains of the rubber network as determined by swelling. The extent of the physical effect of carbon blacks in the elastomers was expressed by the difference between the mechanical deformation values of the filled and unfilled vulcanizates determined at a constant crosslink density.

Harsdörffers Geschirr

2019 ◽  
Vol 10 (1) ◽  
pp. 23-37
Author(s):  
Natalie Binczek
Keyword(s):  
Design History ◽  
History Of ◽  
The Difference

Der deutsche Barockdichter Georg Philipp Harsdörffer skizziert eine Theorie der Emblematik, die vor allem dessen Anwendungsvielfalt hervorhebt. Er hebt dabei besonders den Unterschied zwischen buchinterner und buchexterner Verwendung auf, indem er sich nicht nur für die Aufnahme der Embleme in Büchern, sondern auch auf Geschirr und Tapeten ausspricht. Der Beitrag liest Harsdörffers extensive Überlegungen nicht nur als Beiträge zur Theorie und Geschichte der Embleme als ›Sinn-Bilder‹, sondern auch als Beitrag zur Designgeschichte. German Baroque poet Georg Philipp Harsdörffer delineates a theory of emblematics that clearly sets itself apart from other contemporary theories, especially by its versatility. In particular, the author negates the difference between internal and external usage of emblems in books not only by promoting the incorporation of emblems into printed works but also by supporting their depiction on dishes and tapestries. This article strives to read Harsdörffer’s extensive thoughts on the matter of emblems not simply as another work on the theory and history of emblematics but rather as a contribution to design history as well

Etiology and clinical features of epididymo-orchitis: A single-center study in Tehran, Iran

2020 ◽  
Vol 20 ◽  
Author(s):  
Sara Abolghasemi ◽  
Mohammad Alizadeh ◽  
Ali Hashemi ◽  
Shabnam Tehrani
Keyword(s):  
Chlamydia Trachomatis ◽  
Clinical Symptoms ◽  
Urine Culture ◽  
Clinical Manifestations ◽  
Urinary Frequency ◽  
Serological Tests ◽  
Duration Of Symptoms ◽  
Two Samples ◽  
History Of ◽  
Tract Infections

Introduction: Epididymo-orchitis is a common urological disease among men. Little is known about the clinical and epidemiological aspects of the disease in Iran. Thus, the present study was aimed to investigate the etiology, clinical sequelae and risk factors of patients with epididymo-orchitis in Tehran, Iran. Materials and Methods: Patients presenting with epididymo-orchitis were prospectively analyzed in order to study the etiology and pattern of the disease. Bacteriological, molecular and serological tests were undertaken to look for Chlamydia trachomatis, Neisseria gonorrhoeae, Brucella spp., Mycoplasma spp, and other bacteria. Results: Fifty patients with epididymo-orchitis were evaluated according to their clinical symptoms, duration of symptoms, physical examination, and laboratory studies. The mean age of the patients was 53 years. Fever, dysuria, pain in the flanks, urinary frequency and discharges occurred in 58.0%, 50.0%, 50.0%, 28.0% and 6.0%, respectively. Bacterial pathogen was identified in 26% (13/50) of patients by urine culture. Escherichia coli was the etiological agent in 11/13 patients (84.6%). Two out of 50 patients (4.0%) were also positive for Chlamydia trachomatis. Two samples were serologically positive for Brucella spp. High Mean age, fever, urinary frequency, history of the underlying disease and history of urinary tract infections were found to have a significant association with the positive bacteriologic urine culture (P<0.05). Conclusions: The most common clinical manifestations were fever, dysuria, and abdominal pain. E. coli and C. trachomatis were the major causative agents. Use of a set of diagnostic approaches including clinical symptoms, urine culture and more precise techniques such as PCR should be taken into consideration for the definitive diagnosis.

Introduction

2017 ◽  
Author(s):  
Simon Kirchin
Keyword(s):  
Hilary Putnam ◽  
Bernard Williams ◽  
General Methodology ◽  
Thick Concepts ◽  
History Of ◽  
Philippa Foot ◽  
The Difference

This chapter introduces the distinction between thin and thick concepts and then performs a number of functions. First, two major accounts of thick concepts—separationism and nonseparationism—are introduced and, in doing so, a novel account of evaluation is indicated. Second, each chapter is outlined as is the general methodology, followed, third, by a brief history of the discussion of thick concepts, referencing Philippa Foot, Hilary Putnam, Gilbert Ryle, and Bernard Williams among others. Fourth, a number of relevant contrasts are introduced, such as the fact–value distinction and the difference between concepts, properties, and terms. Lastly, some interesting and relevant questions are raised that, unfortunately, have to be left aside.

The Early History of Financial Economics, 1478–1776. By Geoffrey Poitras. Cheltenham and Northampton: Edward Elgar, 2000. Pp. x, 522.

2002 ◽  
Vol 62 (1) ◽  
pp. 268-269
Author(s):  
Larry Neal
Keyword(s):  
Economic History ◽  
Financial Analysis ◽  
Adam Smith ◽  
Economic Thought ◽  
Financial History ◽  
X 522 ◽  
History Of ◽  
The Difference ◽  
Wealth Of Nations ◽  
Simon Fraser University

Economic historians usually have to explain to their economist colleagues the difference between economic history, which focuses on facts, and history of economic thought, which focuses on ideas. Our colleagues in finance departments, typically fascinated by episodes in financial history treated by economic historians, are bound to be disappointed in the lack of attention given to the development of ideas in finance by historians of economic thought. Geoffrey Poitras, a professor of finance at Simon Fraser University, makes a valiant effort to remedy these oversights in his collection of vignettes that highlight the sophistication of financial instruments and analysts of financial markets well before the time of Adam Smith. Starting in 1478 with the publication of the Treviso Arithmetic, a typical textbook of commercial arithmetic for Italian merchants, and ending with brief snippets from the Wealth of Nations, Poitras treats the reader to a fascinating potpourri of excerpts from various manuals, brief biographies of pioneers in financial analysis, and historical discursions on foreign-exchange and stock markets.

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