bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Chemistry of Soft Rubber Vulcanization. IV Vulcanizing Agents Other than Sulfur
Authors: Garvey B. S. 
Published: February 2011

Abstract
The vulcanizing action of sulfur chloride, m-dinitrobenzene, selenium, tetramethylthiuram disulfide, and benzoyl peroxide has been investigated by the use of a set of tests developed for measuring the degree of vulcanization with sulfur-cured compounds. These tests show that all of these materials are true vulcanizing agents. Comparison of the various vulcanizates with different types of unvulcanized rubber shows that the outstanding characteristic of the vulcanized structure is its resistance to flow under a wide variety of conditions. The vulcanized structure appears to be a composite one which varies with the rate of a reaction catalyzed by the vulcanizing agent, the rate of combination of the vulcanizing agent, the nature of the addition product, and possibly with differences in the nature of the catalyzed reaction.
Alanine in Rubber Latex
Authors: McGavack J. , Rumbold J. S. 
Published: February 2011

Abstract
INDIRECT evidence of the presence of amino acids in ordinary ammonia-preserved latex was obtained from electrometric titration work with the glass electrode, the application of which to latex was described in a previous article (2). A small sample of alanine has now been isolated and identified, and indication of the presence of phenylalanine has also been obtained; however, owing to the small amount of material, its identification could not be established. It is believed that this is the first amino acid to be isolated from latex in the pure state and positively identified; the fact that it has not been detected before may be due to the small amount usually present and to the great solubility of the substance. The only reference found in the literature relating to the presence of an amino acid in rubber is the article by Whitby, Dolid, and Yorston (3). These workers obtained a small amount of d-valine from the acetone extract of pale crepe. Glycine, proline, and leucine are apparently either absent or present in relatively small amounts. If the amino acids are derived from decomposition of proteins, the absence of glycine is rather remarkable since most proteins with a high alanine content—for example, silk fibroin—also contain this amino acid.
Rubber Plasticity Control. Significance and Value of Recovery Measurement of Williams Plastometer
Authors: Dillon J. H. 
Published: February 2011

Abstract
The experiments described in this paper were undertaken in an effort to discover under what conditions the recovery measurement has practical value in plasticity control testing. No conditions were found where the recovery measurement yielded any important practical information which could not be gained by measurement of y value alone. It must be borne in mind that no experiments of this nature can be considered as perfectly general. Certain cases, not specifically included in the experimental conditions employed, may exist where measurement of recovery has definite practical value. Furthermore, great caution should be exercised in applying these results to any types of compression plastometers other than the standard Williams instrument with which the tests were made.
The Perchloric Method for the Determination of Sulfur in Rubber
Authors: Kahane Ernest 
Published: February 2011

Abstract
The problem of the determination of sulfur in rubber has been dealt with extensively in the literature, and it seems as if discussions and descriptions of new technic are nowhere nearly ended yet. The determination is so essential, and its rapid and precise execution is of such importance in industrial technic, that efforts in this direction should not be regarded as wasted. In 1926 and in 1927 Le Caoutchouc et La Gutta-Percha contained two articles in which the present author discussed the conditions of the determination of sulfur in rubber and then proposed the use of a new oxidizing mixture, not mentioned previous to that time, which involved the destruction of organic substances by perchloric acid. This method consisted simply in the attack on a 1-gram sample of rubber by 10 cc. of nitric acid (d. 1.39) and 5 cc. of perchloric acid (d. 1.61). Upon heating, attack by the nitric acid takes place, and this is followed by evaporation of the excess nitric acid, then at a little higher temperature there is an attack by the perchloric acid, which oxidizes the rest of the organic substance completely. This publication was concerned much more, in the determination of sulfur by the perchloric method, with the general idea of the destruction of organic substances than it was with the precise details of carrying it out. The technic had been studied somewhat superficially, as is shown by the text of the article itself.
Alcoholic Potash Extraction of Vulcanized Rubber
Authors: Porritt B. D. , Scott J. R. 
Published: February 2011

Abstract
In the analysis of vulcanized rubber, the estimation of matter extractable by alcoholic potash solution has long been applied, chiefly as a means of detecting and estimating factice. The test was originally made by weighing the rubber before and after boiling with potash solution, the loss in weight being taken as representing the factice content (cf. Weber, The Chemistry of India Rubber, London, 1919, page 245). Though this method has now been generally superseded by that in which the extract is acidified and the resulting fatty acids are extracted with ether and weighed, the older “loss in weight” method is still prescribed in some specifications for rubber goods. It has long been recognized that the loss in weight is not an accurate measure of the factice content for the following reasons: (1) it is difficult to remove all the potash from the extracted rubber before weighing it (cf. Henriques, Chem.-Ztg. 18, 411(1894)), and (2) the potash extracts part of some mineral compounding ingredients, such as zinc oxide, litharge, and antimony sulfide (cf. Ditmar, Die Analyse des Kautschuks, Vienna, 1909, page 205). It has been found that another possible source of serious errors in the “loss in weight” method is the action of the potash on light magnesium carbonate. If magnesium carbonate is boiled with alcoholic potash solution, it loses a considerable amount of its combined carbon dioxide and/or water. Thus in an experiment where 0.3 gram of the carbonate was boiled for 6 hours with 60 cc. of potash solution (KOH 5 g., water 5 cc., absolute alcohol 100 cc.), and then washed with alcohol, dried in vacuo and weighed, it was found to have lost 29.4 per cent of its weight. By igniting the residue to magnesium oxide, it was shown that the potash had not dissolved out any magnesium compounds, so that the loss in weight must be attributed entirely to loss of carbon dioxide and/or water.
Studies in the Vulcanization of Rubber. VI. Thermochemistry
Authors: Blake John T. 
Published: February 2011

Abstract
IN A PREVIOUS paper (2) the heat of vulcanization was studied over the entire sulfur range by heat-of-combustion measurements. Data were also obtained on vulcanization with m-dinitrobenzene and selenium. Although it had been known qualitatively that there was a heat evolution during at least a portion of sulfur vulcanization, definite values were thus obtained for the first time. The results by this heat-of-combustion method are, however, of limited accuracy where small heat changes occur. The method consists in the determining of heat-of-combustion values on a rubber compound before and after vulcanization. Their difference represents the heat content change brought about by vulcanization and involves the subtraction of values of about 10,000 calories per gram. From the data obtained the conclusion was drawn that little or no heat is evolved below 6 per cent sulfur but that there is a steadily increasing heat evolution beyond this to 300 calories per gram of compound at 32 per cent sulfur. The first three points of these data (2, 4, and 6 per cent sulfur) gave an average value of 5 and a mean variation from zero of 18 calories per gram, representing approximately 0.05 and 0.18 per cent of the total heat of combustion—probably the order of the accuracy of the determinations. In the presence of an accelerator (diphenylguanidine) a definite heat evolution was found beyond 4 per cent sulfur, although none appeared at 1 and 2 per cent. Vulcanization of rubber with m-dinitrobenzene and selenium did not seem to give an evolution of heat.
Tear Resistance and Structure of Rubber
Authors: Busse W. F. 
Published: February 2011

Abstract
THE practical importance of tear resistance is so well recognized that numerous tear tests have been proposed (4); all of them are empirical and each gives results which differ, usually in unpredictable ways, from all others. However, with all their imperfections the common tear tests give information about rubber compounds that cannot be obtained by any other means. They have been used extensively to study the effects of pigments on rubber, particularly in trying to determine why gas black greatly improves tear resistance while other pigments, such as clay and whiting, reduce it. Unfortunately, many workers did not even recognize that gas black causes a different kind of tear from that found with other pigments. This is not true of Talaly (5) and Kirchhof (3) who recently published data on the knotty tear of gas black and latex stocks. The theoretical importance of tear tests has been almost totally ignored in spite of the fact that some tests, such as hand tear, are particularly sensitive to the structural changes that occur during cure, and almost all of the tests are sensitive to the effects of pigments on the structure of the rubber. A satisfactory theory of tear testing would not only lead to increased precision in practical tear tests, but there is every reason to believe that it would also yield a better understanding of the structures present in rubber.
A Mathematical Treatment of a Theory of Rubber Structure
Authors: Griffith T. R. 
Published: February 2011

Abstract
A brief consideration of the work that has been done on the structure of rubber convinces, one that the elasticity is wholly or at least mainly explained by a consideration of the kinetics involved. The fact that when a strip of stretched rubber, one end of which is free, contracts when it is warmed, contrary to the behavior of most bodies, and that it becomes warmed on stretching, commonly known as the Gough-Joule effect, pp. 453–461, would lead one to suspect .that there is a connection between the kinetic energy of the rubber molecule and its elasticity. Lundal, Bouasse, Hyde, Somerville and Cope, Partenheimer and Whitby and Katz have reported observations, principally stress-strain curves, which show that vulcanized rubber has a lower modulus of elasticity at higher temperatures, i. e., it becomes easier to stretch as the temperature is raised. On the other hand, Schmulewitsch, Stevens, and Williams found that the elastic modulus increases with the temperature. Williams shows that the softening of vulcanized rubber with rise of temperature is due to an increase of plasticity. In order to get rid of plastic flow, he first stretches the specimen several times to within about 50 per cent of its breaking elongation, and then obtains an autographic stress-strain curve of the rubber stretched very quickly. He finds that in this case the rubber actually becomes stiffer with rise of temperature, increasing temperatures causing the stress-strain curves to lean progressively more and more toward the stress axis. He concludes that rise of temperature has two effects, one a softening due to increase of plasticity, rendering plastic flow more easy, the other an actual stiffening of the rubber due to rise of temperature. It is not easy to explain the latter effect on any theory which does not take kinetics into account.
Forms of Rubber as Indicated by Temperature-Volume Relationship
Authors: Bekkedahl Norman 
Published: February 2011

Abstract
This paper describes measurements of the change of volume of rubber with change of temperature, which have been used as a means for determining the forms in which rubber may exist and ascertaining the conditions under which transition from one form to another may occur. This work is part of a study of the basic thermodynamic properties of rubber which is being conducted at the cryogenic laboratory of the National Bureau of Standards. In this study, an attempt was first made to measure the heat capacity of rubber over a wide range of temperature, but under some circumstances anomalies due to change in phase were encountered which took place so slowly that it was impracticable t0 follow them through by calorimetric methods. These anomalies have been studied by the measurement of the changes in volume or coefficient of expansion associated with them, it being possible to follow changes in volume over as long a period of time as desired. At temperatures at which rubber is relatively stiff and rigid, measurements of length have been used as an adjunct to the volume measurements. Measurements of the temperature-volume relations of rubber have been made by several previous investigators who have recognized the existence of rubber in different forms. The contribution of the present investigation lies in the fact that it reports a somewhat more comprehensive and systematic study than has been made previously. The findings are largely in accord with those of the other workers, as will be brought out in a subsequent section of the paper.
Accelerators in Hard Rubber
Authors: Davies B. L. 
Published: February 2011

Abstract
1. The curve relating the hardness to the time of heating of a high-sulfur stock indicated the presence of two consecutive reactions. The second half of the curve was mainly linear, and its slope might be used as a measure of the second (hard rubber) reaction speed. 2. The straight line when produced downwards passed through or near to the origin. Its position was altered only slightly by normal variations in processing. 3. The straight line may be represented by the equation H=rt+ƒ where H = per cent hardness by Shore's Durometer, t = time of heating in minutes, r = rate of hard rubber formation represented by the tangent of the angle between the curve and the time axis, and ƒ = the intercept along the hardness axis. 4. Influences which are known to increase the speed of chemical reactions increased the slope of the line. Thus, increase of sulfur concentration, rise of vulcanizing temperature, and the presence of catalysts increased the value of r, yielding a “fan” of lines all passing through a point near to or coincident with the origin. 5. The organic accelerators of vulcanization in general were found to act as true accelerators if present in small amounts. With increasing concentration they increased the speed of hardening at 150° C. up to a definite maximum, which appears to be approximately the same for many accelerators. 6. From an investigation of the minimum concentration of accelerator which produced the maximum slope, numbers representing the efficiency of the accelerators have been found. 7. Further addition of accelerator produced no further change in r, but a definite and progressive increase in the value of ƒ. This effect was also produced by the addition of mineral fillers. 8. If the value of H be taken as 100 per cent hardness, the equation H=rt+ƒ may be used for determining the time of cure. r is the rate of cure, dependent upon the nature of the accelerator, and the nature and amount of filler determine the magnitude of ƒ. Values of ƒ referring to some commonly used fillers have been determined. 9. The effect of increasing the temperature of vulcanization on the rate of hardening was examined. It was found that the temperature coefficient of hard rubber formation was not a constant quantity for accelerated hard rubber stocks. In many cases its magnitude increased to a maximum within the temperature range 140–150° C., and then fell at still higher temperatures.
Investigations of Unknown Components of Crude Rubber. I. Copper Content of Different Types of Crude Rubber
Authors: Shimada Keiichi 
Published: February 2011

Abstract
Small amounts of copper have been found to be present normally in all types of crude rubber. Standard smoked sheet and fine pale crepe contained 3.13 mg. and 2.32 mg. of copper, respectively, per kg. of rubber, whereas fine hard Para had a relatively large amount, viz., 5.50 mg. per kg. of rubber. Considering the wide distribution of copper in minute quantities in biological materials, it is most probable that the copper in the crude rubber is introduced from the original latex. The micro-estimation of copper in crude rubber was carried out by the colorimetric method proposed by the present author (J. Soc. Chem. Ind., 36, 263B (1933)), the procedure recommended by Ansbacher, Remington, and Culp (Ind. Eng. Chem., Anal. Ed., 3, 315 (1931)) for destroying the sample and dissolving the rubber ash being applied.
Determination of Free Sulfur in Rubber. I. Iodometric Method of Determination of Free Sulfur
Authors: Bolotnikov V. , Gurova V. 
Published: February 2011

Abstract
Up to the present time the determination of free sulfur has been carried out by extracting the rubber by acetone, followed by oxidation of the sulfur with bromine to sulfuric acid. This method has very substantial drawbacks, such as the fact that each determination of sulfur requires many hours, and the results of the analysis are received in the best cases on the second day. The method developed by the present authors is based on the iodometric method for the determination of sulfides, sulfites, and hyposulfites in the presence of one another. The rubber is treated with a solution of sodium sulfite Na2SO3, which transforms the free sulfur into hyposulfite, thus: Na2SO3 + S → Na2S2O3. The resulting solution. contains Na2SO3and Na2S2O3. The sample, about 2 g. of finely cut rubber, is put into an Erlenmeyer flask of 250–300 cc. capacity, and 100 cc. of 5% solution of sodium sulfite are added. Tests have shown that the best extraction of sulfur takes place in the presence of an excess of Na2SO3 over that required by the reaction. Five grams of dry sodium sulfite enough to extract from 0.05 to 2% S.
The Biofeedback Odyssey: From Neal Miller to Current and Future Models of Regulation
Authors: Binnun Nava Levit , Golland Yulia , Davidovitch Michael , Rolnick Arnon 
Published: February 2011

Abstract
Neal Miller's research on animals and humans launched the field of self-regulation, enabling individuals to take a more active role in their health and well-being. However, his inquiry into whether autonomic operant conditioning occurs remains open to debate. This article contends that present-day biofeedback therapists continue to be confronted by this dilemma. In addition, the authors suggest other models of biofeedback in which the role of the practitioner has been expanded and to which a large repertoire of self-regulation techniques have been added. They propose that, in the future, the regulatory capacity of interpersonal interactions is recognized as in the proffered model of biofeedback, dyadic biofeedback (DBF). DBF allows for real-time training of interpersonal interactions, emphasizing learning through direct observation and active involvement, thus making a return to Miller's model.
Ex Vivo Examination of the Biocompatibility of Biodegradable Magnesium via Microdialysis in the Isolated Perfused Bovine Udder Model
Authors: Schumacher Stephan , Stahl Jessica , Bäumer Wolfgang , Seitz Jan-Marten , Bach Friedrich-Wilhelm , Petersen Lars J. , Kietzmann Manfred 
Published: February 2011

Purpose Being biodegradable, magnesium is considered a promising future implant material but very little is known about the biocompatibility for the tissues in direct contact with it. In this study, the degradation of pure magnesium implants in the skin of an isolated bovine udder was examined over a period of five hours. Methods Microdialysis technique was used in order to investigate the reactions at the interface of implant and tissue. Pure titanium implants served as control. Degradation behavior and biocompatibility were evaluated via extracellular magnesium ion concentration and PGE2 and TNF alpha served as indicators of inflammation. Results Concentrations of 5.5 mmol/l Mg2+ were detected at the beginning, which decreased to a plateau of about 3.5 mmol/l after approximately two and a half hours. PGE2 and TNF alpha concentrations indicated no major inflammatory tissue response to the degradation. Conclusions These results give an idea of the ion burden at the implantation site of degrading magnesium and suggest good biocompatibility even at the tissue-implant interface.
Rationale for Industrial Hygiene Practice
Authors: Harris Robert L. , Cralley Lewis J. , Cralley Lester V. , Rose Vernon E. 
Published: February 2011

AbstractThe professional field of industrial hygiene has its roots in the profession of public health, which means the preservation of health and prevention of disease among people engaged in systematic labor for some useful purpose or the creation of something of value. The modern definition of industrial hygiene also includes protection of the health of persons living around a place of work from hazards that may arise from that place of work. This chapter focuses on various factors that are involved in relating environmental stresses to health and the rationale upon which the practice of industrial hygiene is based. A significant progress has been made during the past few decades in characterizing and controlling environmental health hazards in places of work. Various comprehensive industrial hygiene programs are being used effectively and exposures to work hazards are often well controlled. The techniques used in assessing occupational health stresses cover all the relevant components of each stress and ensuring that these are addressed in resulting control program.
Basic Aerosol Science
Authors: Reist Parker C. 
Published: February 2011

Abstract
Aerosol contaminants can be injurious to health, therefore it is essential to understand the behavior and properties of the aerosol. Health effects caused by aerosols depends on particle size and size distribution as well as on the composition of the particles. Other aerosol behavior including light scattering and coagulation can also vary markedly with particle size. This chapter focuses on various properties of the aerosol particle which influence the behavior, such as Stokes law, Reynolds number, Cunningham correction factor, particle motion, electrical properties, and optical properties.
Computed Tomography in Industrial Hygiene
Authors: Todd Lori A. 
Published: February 2011

AbstractA variety of innovative measurement technologies have been used by industrial hygienists to evaluate human exposures to contaminants, monitor process emissions and leaks, and determine the effectiveness of ventilation systems. Temporal resolution has been reported important for understanding and effectively controlling the generation and transport of contaminants in air, for identifying chemical intermediates produced during a process, and for monitoring chemicals that are acutely toxic. Real‐time instruments are used to provide good temporal resolution of concentration fluctuations. The technique also combines the real‐time chemical detection methods of optical remote sensing. The environmental CT system generates near real‐time spatially and temporally resolved two‐dimensional concentration maps of multiple chemicals at low limits of detection. Besides this, refinement of ORS instrumentation and low cost retroreflector arrays has also been discussed.