bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hand injuries due to high‐pressure injection devices for painting in shipyards: Circumstances, management, and outcome in twelve patients
Authors: Valentino Matteo , Rapisarda Venerando , Fenga Concettina 
Published: April 2003

AbstractBackgroundInjuries due to high‐pressure injections are frequently underestimated occupational accidents, which may have disabling outcomes.MethodsThe occupational injuries logbooks of two shipyards were examined. Twelve accidents due to the utilization of high‐pressure equipment were reported. Data were obtained by reviewing the employers' logbooks and hospital records.ResultsContaminants were epoxy paint and stucco, paint solvent, hydraulic and industrial oil. In three cases, the palm was injured and the fingers in nine. In 91% of cases, the accident occurred in the last 2 hr of the work shift. Mishandling (n = 9) and rupture of the high‐pressure equipment (n = 3) were the causes. Mean time to medical treatment was 42.5 hr (SD 56.0). Ten workers were permanently disabled.ConclusionsPrompt surgical intervention with debridement and decompression was done in two workers, who healed completely. The ten patients who were not treated immediately eventually experienced a high rate of disability and five of them also suffered amputation. Am. J. Ind. Med. 43:539–542, 2003. © 2003 Wiley‐Liss, Inc.
A study of diffusion in solids of arbitrary shape, with application to the drying of the wheat kernel
Authors: Becker H. A. 
Published: April 2003

AbstractA general mathematical approach to the rigorous treatment of experimental data on nonstationary‐state diffusion in solids of complex shape is developed. The general solution for a uniform initial concentration, c0, and a constant surface concentration, cs, at times greater than zero is shown to be of the form

in the neighborhood of time zero, and

in the neighborhood of time infinity, where c is the average concentration at time t; S and V are the surface area and volume of the solid, respectively; D is the diffusion coefficient; and f″ (0), α, and β are constants dependent on solid shape. The vacuum drying of wheat has been studied, and it is shown that, for the wheat kernel, f″ (0) = 0.588, α = 0.862; and β2 = 1.301. The diffusion coefficient is an Arrhenius‐type function of temperature given by D = D0 exp {‐E/RT} where D0 = 76.8 cm.2/sec. and E = 12.20 kcal./mole.
Dynamic mechanical properties of nylon 66 and the plasticizing effect of water vapor on nylon. II
Authors: Quistwater J. M. R. , Dunell B. A. 
Published: April 2003

AbstractThe dynamic tensile modulus and energy loss have been measured for nylon 66 monofilaments at 9 and 60°C. over a wide humidity range in forced longitudinal vibration experiments. The frequency range covered was about 3 to 30 cycles/sec. (radian frequency 20 to 200 sec.−1). The results show dispersion of mechanical properties with change in humidity at both temperatures. At 60°C. a well‐defined maximum in the energy loss was observed, similar to that obtained previously at 35°C., but occurring at a somewhat lower water content. If a maximum in the energy loss exists at 9°C. (it is not well‐defined), it occurs very near 100% R.H. A time‐humidity superposition procedure is discussed by means of which the individual curves of modulus against frequency for the various humidities can be combined into a single “master curve” of modulus against reduced frequency. The order of magnitude of the activation energy for the dissipation mechanism has been estimated at 60–80 keal./mole.
Diisocyanate‐linked polymers. I. Dilute‐solution properties of toluene diisocyanate‐extended polypropylene glycol
Authors: Moacanin J. 
Published: April 2003

AbstractA study was made of the dilute solution properties and the molecular weight distribution of a polyurethane polymer prepared from polypropylene glycol 2025 and toluene‐2,4‐diisocyanate by a bulk polymerization under anhydrous conditions at 60°C. Such conditions were chosen to minimize possible side reactions which could produce branching. The polymer, which had a weight‐average molecular weight of 36,500, was separated into fourteen fractions by fractional precipitation from a benzene solution with isooctane as precipitant. The fractions were characterized by light scattering measurements on methanol solutions and by dilute solution viscosities in methanol, benzene, and a theta‐solvent. The molecular weight distribution of the unfractionated polymer and the relations between molecular weight and intrinsic viscosity in the various solvents were determined. Polymer configurations and interaction parameters are discussed.
Determination of degree of crosslinking in natural rubber vulcanizates. Part III
Authors: Mullins L. 
Published: April 2003

AbstractImprovement in methods of characterizing the stress‐strain properties of vulcanized rubber and of determining its molecular weight prior to vulcanization are described. Experimental results obtained previously by Mullins, Moore, and Watson, in an attempt to relate the physical properties of natural rubber to their network structure, are critically re‐examined to take account of these developments. It is shown that if empirical corrections are made for the effect of network flaws due to chain ends and for a second type of network defect equivalent to chain entanglements, then estimates of the degree of crosslinking derived from physical measurements and from chemical determinations are in remarkably close accord.
Chemorheological study of cured polysulfide liquid polymers
Authors: Colodny P. C. , Tobolsky A. V. 
Published: April 2003

AbstractThe effect of curing agents and their reaction products upon the disulfide interchange reaction of cured liquid polysulfide polymers was studied. The curing process involved the oxidation of the mereaptan terminals of the liquid polymer to disulfide linkages or the reaction of these end groups with some polyfunctional reagent. Several different types of cure were attempted on the same batch of the liquid polymer including oxidation by metallic oxides, organic peroxides, and hydroperoxides, p‐quinonedioxime, and catalyzed air oxidation. Cures were also obtained by the use of diisocyanates. The disulfide interchange was studied by means of stress relaxation. It was found that the rate of exchange was greatly accelerated by the presence of ionic or alkaline materials. In their absence the exchange reaction proceeded quite slowly. The incorporation of excess sulfur also increased the reaction rate. The mechanism of the reaction is believed to be predominantly ionic.
Investigations of the phenomena of coacervation
Authors: Turska E. , Utracki L. 
Published: April 2003

AbstractThe object of the work was to ascertain the characteristic features which could provide a basis for distinguishing between the formation of the coacervate and that of a new liquid phase resulting from the limited miscibility of components. Various multicomponent systems containing the polymer were examined, and as a model we examined a system unable to form coacervates in which the polymer was replaced by a small‐molecule substance of a similar solubility. Measurements of the changes in the volumes of the liquid phases were carried out and the polymer content in the particular phases was determined. It was ascertained that the characteristic feature for the coacervate is a maximum on the curve which indicates the dependence of the volume of the phase richer in polymer on the quantity of the nonsolvent used. The polyethylene terephthalate coacervate was obtained and certain new systems containing polyamides were proved to be able to form coacervates.
Condensation polymers from diisocyanates and dioximes
Authors: Campbell Tod W. , Foldi Veronika S. , Parrish Robert G. 
Published: April 2003

AbstractDiisocyanates condense readily with the two active hydrogen atoms in dioximes to give high molecular weight linear condensation polymers. In several cases these polymers, such as the one from cyclohexanedione dioxime and 4,4′‐biphenylene diisocyanate,
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may be converted to tough films or fibers. Thermal, hydrolytic, and light stability of these polymers were in general poor.
Large‐scale polymer fractionation by gradient elution. Some operating principles
Authors: Pepper D. C. , Rutherford P. P. 
Published: April 2003

AbstractA detailed analysis of the factors operating in polymer fractionation by gradient elution column methods is offered. A comparison between experimental fractionations of a range of polystyrenes indicates that the most important single factor is the concentration of polymer permitted in the eluant. For the logarithmic composition gradient considered here, the average concentration in the eluant may be controlled through control of the volume of the eluant in the mixing vessel. This volume should be not less than 200 times the volume of the polymer sample, and considerably larger if the polymer is of high molecular weight.
Effect of oxygen pressure on the thermal degradation of a methylphenylsilicone
Authors: Scala L. C. , Hickam W. M. , Loeffler M. H. 
Published: April 2003

AbstractThe manner in which changes in air pressure affect the thermal and oxidative degradation of a methylphenylsilicone was investigated as a function of time. A closed, gas‐circulating system of 1500‐cc. volume, incorporating a magnetic balance for following loss of weight in the sample, was employed. Finely ground samples were heated at 400°C. for 7 hours with initial pressures of air ranging from 700 to 50 mg. Hg. Mass spectrometric and infrared analyses identified the gaseous and the volatile products. At all pressures, low molecular weight silicones represented a major portion of the weight loss. Final weight losses in air approximated 10%, and approached, at the lowest pressure (50 mm.), the 7% observed in argon. Water and benzene were evolved, the latter at a rate that decreased with decrease in pressure. Traces of phenol, formaldehyde, propane, and higher molecular weight hydrocarbons were also given off. The evolution of carbon dioxide, carbon monoxide, methane, and hydrogen and the consumption of oxygen were followed in detail. Changes in air pressure from 700 to 300 mm. did not alter appreciably the rates of product evolution, oxygen consumption, and of weight loss. At lower presures (300 to 50 mm.), however, the molar ratio of the total noncondensed gases generated to total oxygen consumed increased, indicating a possible change in reaction mechanism.
Measurement of the flow of thermosetting molding compound
Authors: Ito Katsuhiko 
Published: April 2003

AbstractThe extrusion rheometer, suggested by the author, is used for the relative measurement of the flow of thermosetting molding compounds in a curing process which is more complicated and difficult to measure than that of thermoplastics. Allyl polyester molding compound, which contains asbestos as a filler in the amount of 50% and Luperco ATC as a catalyzer in the amount of 4%, is used as a test sample of the thermosetting compound. Because the unsaturated polyester which is used as a resin in the test sample of the thermosetting compound contains diallyl phthalate monomer, which acts as a crosslinking component in the radical polymerization reaction, there is no volatile by‐product in the curing reaction. Therefore, breathing during the molding of this test sample is not needed, and this allyl polyester molding compound is considered to be most suitable to use as the test sample of the thermosetting molding compound. Several factors which exert an influence on the flow of the thermosetting compound in the curing process are investigated, and recommended testing conditions are determined. Although the flow curve of the thermosetting molding compound in the extrusion rheometer is not as simple as that of thermoplastics, the flow characteristics of the thermosetting molding compound can be evaluated and compared by the factors Rf, vf, fts, and fte, which are obtained from the flow curve. As an example, the influences of time‐aging effect and various fillers on the flow of the thermosetting molding compound are examined by the above method.
A loss in curing test for tire cords
Authors: Reegen S. L. , Sabo J. 
Published: April 2003

AbstractA laboratory method for determining the effect of curing conditions on the tensile strength of tire cords has been developed which makes use of rubber‐cord pads cured in a mold. The tensile strengths of the cured cords embedded in rubber are measured after removal from the mold. The method is suitable for nylon cords, either bare or dipped. It has been determined that tensile strength losses during curing of nylon are caused by shrinkage of the cords in the presence of moisture.
Mechanism of antioxidant action in the stabilization of hydrocarbon systems
Authors: Shelton J. Reid 
Published: April 2003

AbstractFour antioxidant classifications, based on differences in the method by which they exert their effect, are noted. The mechanism of the chain‐stopping action is discussed in terms of four different reactions which have been proposed. The participation of the antioxidant in the mechanism of inhibited thermal oxidation is reviewed. The hydrogen donation mechanism as the first step in the chain‐stopping mechanism has been investigated by observing the effect of replacing the active hydrogen of the antioxidant by deuterium. Contrary to the findings of some prior workers, a kinetic isotope effect has been demonstrated with a secondary aryl amine antioxidant as well as with phenols. These results, together with other supporting evidences reported in the literature, indicate that abstraction of a hydrogen from the antioxidant is the initial step in the usual mechanism by which antioxidants serve as chain stoppers in the oxidation of hydrocarbon systems.
A study of time dependence of polyethylene flow in capillary viscometry
Authors: Schreiber H. P. 
Published: April 2003

AbstractIt is known that polyethylene extruding from a capillary viscometer does not attain a steady‐state output rate immediately following a pressure imposition. The time dependence of output rate was studied quantitatively, and under some extrusion conditions was found to be of surprisingly large magnitude. The most notable effect is an overall rise in the output rate; its magnitude and duration depends on the extrusion pressure and temperature and on the entry geometry of the die employed. The magnitude of the effect is also characteristic of particular polyethylene samples and seems associated with smooth filament extrusion of the polymer. The steady‐state output rate can exceed the initial rate by as much as 40%. The rising output rate characteristic has been associated with a decreasing melt viscosity. This is taken to be the result of configurational changes occurring in the extruding melt. The data are shown to be qualitatively consistent with this postulate.
Number and size distribution of particles in cellulosic solutions
Authors: Parks L. R. , Jurbergs K. A. 
Published: April 2003

AbstractA large amount of work has been reported in the literature on the influence of insoluble materials on the viscose process. Detrimental effects of insolubles on filtration has been the subject of the majority of the research in the past, but some efforts have included studies of the effect of insolubles on yarn strength. A wide range of physicochemical techniques have been applied to the problem with varying degrees of success. Counting of the insoluble particles has been mainly done by microscopic methods or equipment utilizing the breaking of a light beam and photoelectric detection. In the work reported herein, a commercially available particle counter (Coulter counter) which operates on electronic principles has been applied with considerable success to cellulosic solutions. The instrument permits determination of cellulosic particle sizes and size distributions in the size range of real interest to cellulose workers (4–50 μ) and over an even wider range with other accessories. Viscose solutions, diluted 1:10 with dissolving caustic, have been counted before and after filtration. The number of counts varies considerably with species, pulp type, processing conditions, and the presence or absence of surfactant. Filtration through a medium similar to that used in commercial viscose preparation causes a fairly sharp drop in the number of particles greater than 8 μ. The counts below 8 μ are not changed appreciably by filtration. The filter cutoff of cellulose acetate solutions (diluted to similar concentrations) is much less sharply defined. Acetate counting is done in aqueous acetone solution with sulfuric acid as electrolyte. Coulter counts parallel microscopic values, but are far less laborious, and more information about the size distributions is obtained. The instrument has also been used to evaluate filter media for both viscose and cellulose acetate filtration.
Temperature dependence of dynamic mechanical properties of mixed polymer systems
Authors: McIntyre A. D. 
Published: April 2003

AbstractThe temperature dependence of the viscous component E2(1/T) of the dynamic modulus is reported for a homologous series of butadiene–styrene copolymers incorporated at various levels in styrene homopolymer. By the use of a vibrating reed technique based on resonance tuning, the frequency of the applied deformation was maintained essentially constant throughout the temperature range which included the glass transitions of the copolymers. It is shown that, when E2(1/T) for such mixed polymer systems is plotted against reciprocal absolute temperature, the area under the peak corresponding to a given copolymer affords a direct measure of the quantity of the copolymer present. Further, the temperature of maximum E2(1/T) is related to the mole fraction of bound styrene in the copolymer, and the shape of the peak is related to the statistical sequence lengths of styrene and butadiene in the copolymer.
Peroxide‐ and radiation‐cured compounds filled with reinforcing fine‐particle silica
Authors: Sellers J. W. , Wagner M. P. , DeWitt B. J. , Stueber C. C. , Bachmann J. H. 
Published: April 2003

AbstractThere are indications that the chemical reaction involved in bound rubber formation proceeds via a free‐radical mechanism for compounds filled with reinforcing hydrated fine‐particle silica, as well as in the case of carbon black as filler. The high potential of silica as a rubber reinforcer is indicated by its bound rubber formation. This potential was realized by the extent of filler‐polymer interaction developed in silica‐filled vulcanizates cured by peroxide and by high‐energy radiation, respectively. Both these relatively simple curing systems are postulated to effect crosslink formation via a free‐radical mechanism. The value, after cure, of the ratio of the crosslink density of the filled compound to the crosslink density of the respective unfilled compound, η/η0, was taken to be a logical measure of the ability to reinforce. In natural rubber compounds filled with silica (30 vol.), the values of η/η0 obtained were 1.6–1.9 for peroxide‐cured material, and 3.6 for radiation‐cured material. Comparisons are made with similarly cured HAF black‐filled stocks. Sulfur‐cured natural rubber stocks filled with HAF black (30 vol.) generally exhibit η/η0 values in the range of 1.5 to 2.0. Comparative effects of antioxidants are described.
Electron spin resonance studies of polyvinyl chloride irradiated in NH3 gas
Authors: Ueda Hisashi , Kuri Zen'ichiro , Shida Shoji 
Published: April 2003

AbstractThe electron spin resonance of polyvinyl chloride (PVC) irradiated in NH3 was studied. The radicals produced on irradiation in NH3 do not differ greatly from those obtained on irradiation in vacuum, but the reactivity of the former to SO2 to form RSO2ċ radicals is far higher than that of those obtained in vacuum. The radicals produced by irradiation at −78°C. and in vacuum was also studied. The spectra of these radicals were different from those of the radicals produced at 20°C. and in vacuum. The reactivity of the radicals produced in PVC is interpreted on the basis of the length of double bonds conjugating with the radical π‐electron.
A quantitative study of crosslinking cotton with N‐methylol acrylamide
Authors: Gardon John L. 
Published: April 2003

AbstractCotton was acrylamidomethylated by applying N‐methylol acrylamide to it with the aid of a mild acid catalyst. When the molal ratio of N‐methylol acrylamide to anhydroglucose exceeded about 0.2, the efficiency of this reaction was suddenly reduced and the variation of density with addon departed from linearity. These and other available facts indicated that only one of the three hydroxyls in cellulose, probably the one in the 6‐position, was involved in the acrylamidomethyl ether formation and that cotton was about 20% accessible to this reagent. When acrylamidomethylated cotton was treated with free radical or alkaline catalysts, the double bonds became partially saturated and the mechanical properties changed in a spectacular manner. In particular, the resilience of the fabric, as measured by crease recovery, was improved. Analysis of double bond reaction at various levels of acrylamidomethyl content of the fabric indicated that free radical catalysis caused homopolymerization of the pendant double bonds, that alkaline catalysis in the presence of water resulted in Michael condensation between double bonds and the hydroxyls of cellulose, and that these two reactions competed with each other when the alkaline aftertreatment was conducted in dry state. These reactions crosslinked the fabric, and the crosslink content could be calculated from the difference of molal methylene and double bond contents.The crease recovery reached the maximum attainable value characteristic for the method of catalysis when the ratio of accessible anhydroglucose units to crosslinks was 4 to 5. When the crosslinked fabrics were hydrolyzed in acid, the crease recovery increment produced by crosslinking was eliminated after about half of the crosslinks were broken. The residual crosslinks did not contribute to crease recovery. Dry state crosslinking treatments reduced the moisture regain, increased the density, and had no effect on the x‐ray pattern. In contrast to this, wet state crosslinking in‐increased the moisture regain, changed the x‐ray pattern, and, under certain conditions, reduced the density. These results indicate that wet state crosslinking increased the amorphous portion of cotton. Wet state crosslinking lead to higher wet than dry crease recovery whereas the opposite was true for dry state crosslinking. Although the alkaline catalyst did not degrade the fabric, alkali catalyzed crosslinking substantially reduced the tensile strength. Free radical catalysis was more favorable for tensile strength, in spite of the fact that it degraded the fabric in the absence of crosslinking agent.