bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of Biophysical Parameters of Wheat Retrieved from Sentinel-2 Data Using in-situ Measurements at Anand Region of India
Authors: Chauhan K. K. , Lunagaria M. M. 
Published: January 2024

The purpose of this study was to evaluate the accuracy of the Sentinel-2 chlorophyll content and the Leaf Area Index (LAI) retrieved via SNAP toolbox using in situ observed biophysical parameters. SL2B plugins were tested for accuracy and consistency through validation and comparison of spatial variation. The SNAP processor showed good correlations for Leaf Area Index (LAI) in the first year, and it was particularly successful in some selected fields. For the various areas, satisfactory accuracy was maintained in the second year. The findings revealed a reasonable R2, ranging from 0.5 to 0.7, between in-situ LAI and SNAP-retrieved LAI, but with high errors. In chlorophyll assessment, the average estimates of SL2P-derived values were 20 – 90 µg/cm², against the mean values of 40–50 µg/cm² as observed in the field. The standard deviation for the chlorophyll generated from SL2P, albeit variable, was moderate (22.68 µg/cm²). The scatter plots highlighted a close agreement between retrieved and measured values, reinforcing the reliability of the data. Retrievals of LAI and chlorophyll were accurate for Anand district. It highlights the potential of Sentinel 2 data for reliable retrieval of biophysical parameters of wheat.
Softener absorption by regenerated cellulose. Uptake from 10% aqueous glycerol
Authors: Sweeting Orville J. , Mykolajewycz Roman , Wellisch Eric , Lewis Richard N. 
Published: April 2003

AbstractThe softener content of regenerated cellulose film (gel film) in equilibrium with aqueous glycerol solution was found to be determined primarily by only two factors: the softener concentration of the solution and the volume of free space within the gel film. Volume changes of film in contact with 10% glycerol solutions are negligible. Preferential uptake of glycerol as the solution passes into the film is, at most, slight, amounting to no more than 0.04% at the concentration used. No evidence was found for a large enrichment within the gel film, as has been postulated, or for adsorption of glycerol on cellulose chains. The system, cellulose‐glycerol‐water, appears to be a polymer‐liquid mixture brought to equilibrium principally by diffusion. It appears that at 10% concentration, glycerol and probably other organic compounds are taken in by gel film by a diffusion process in which the free water in the film is replaced by solution without appreciable enrichment or change in volume. Water contained in the interchain spaces of cellulose is simply exchanged for softener solution. The free volume of the film as determined by the cellulose structure and the degree of crystallinity remains essentially unchanged on softener uptake at the softener concentration studied.
Stabilization of viscose rayon by heat treatment by means of ammoniacal preswelling bath
Authors: Kanamaru Kisou 
Published: April 2003

AbstractIn continuation of a previously reported experimental study on stabilizing viscose rayon by heat treatment, in which acid baths were used as the preswelling agents for heat treatment of regenerated cellulose further experiments were performed in which ammonium hydroxide solutions served as the preswelling agent. From the effects of heat treatment of the fibers preswollen in ammonium hydroxide bath, as exhibited by dynamic modulus, breaking strength, degree of crystallinity (estimated from x‐ray data), etc., it was confirmed again that, when viscose rayon preswollen in an ammonium hydroxide bath of the concentration or the pH range optimal for it maximal hydration (pH = 9.0) is heat treated at the temperature just above the glass transition temperature of regenerated cellulose (ca. 70–90°C.), the effects of the heat treatment in stabilizing viscose rayon are most marked. Moreover the effects of heat treatment, as exhibited by these properties of rayon at the optimal condition are much larger in this case than when the heat‐treated fibers are preswollen in an acid bath. This effect is also clearly indicated by the results of infrared spectroscopy studies according to the deuteration method. With the use of a series of fiber samples preswollen in acetic acid as well as ammonium hydroxide bath and dried at various degrees of desiccation results were obtained which indicate that there is an optimal degree of desiccation for effecting maximal stabilization.
Chemical and physical nature of insolubles: Acetone solutions of cellulose acetate
Authors: Sperling L. H. , Easterwood Marie 
Published: April 2003

AbstractAn examination of the chemical and physical properties of gels in wood and linters cellulose acetates was carried out with special emphasis on light‐scattering and electron microscopy. Gels were fractionated by filtration, centrifugation, and dialysis techniques to produce gels over and under 15 microns in size. The predominant phenomena observed in the small gels are nearly monodisperse spherical or potato‐shaped gels of about 0.3 micron in dispersion (light‐scattering) and 0.1 micron dry (electron microscopy). Chemical analysis shows these gels much enriched in xylan. The large gels were examined also and were found to consist of fibers (cellulose I) and plates (cellulose triacetate).
Infrared spectroscopic studies of ultrathin microtomed sections of polymers. Part I. Characterization and structure determinations of cured, black‐loaded rubbers
Authors: Corish P. J. 
Published: April 2003

AbstractPrevious time‐consuming, destructive methods for examination of infrared spectra of cured, black‐loaded rubbers have been replaced almost entirely by a rapid new technique which examines the rubber in its original form. By use of ultrathin microtomed sections (ca. 2 μ thick) of the rubber and electrical amplification of the absorptions on a recorder quite good infrared spectra of the rubber may be obtained. Characterization and structure determination of the rubber can then be carried out. Many different polymers, copolymers, and mixtures of polymers which have been loaded with up to 60 parts phr of carbon black and cured have been characterized in this way. Typical applications to determinations of polymers in tires, etc. are described. The effect of variation in particle size of carbon black is considered.
A proposed method for estimating polymer molecular weight distribution without fractionation
Authors: Rehner John 
Published: April 2003

AbstractA method is proposed for estimating rather simply and with relatively little experimental data the molecular weight distribution characteristics of any crosslinkable polymer which follows the Tung distribution function. This function is combined with a fundamental relationship from the statistical theory of sol–gel ratios in randomly crosslinked polymers, to yield a result which relates explicitly the sol‐gel ratio, the crosslink density, and the molecular weight distribution parameters. These parameters give the various average molecular weights and the polydispersity by simple computation. The method has been tested with meager data available for a peroxide‐cured SBR and a divinylbenzene‐crosslinked polystyrene. Reasonably satisfactory results were obtained. A critical test of the absolute accuracy of the method requires experimental data not now available, and some refinements may eventually have to be made. However, the method should be useful, in its present state, for estimating distribution characteristics and, especially, for comparative studies within a given polymer system.
The oxidative aging in ultraviolet light of dicumyl peroxide vulcanizates of natural rubber in presence of various antioxidants
Authors: Dunn J. R. 
Published: April 2003

AbstractThe oxidative degradation of peroxide vulcanized natural rubber at wavelengths of 300 mμ and above has been studied by the technique of stress relaxation. Substituted naphthylamines and p‐phenylenediamines, particularly the former, initially photosensitize the degradation of the vulcanizate but subsequently give rise to colored products which act as antioxidants. The protective action of these amines is not due to network formation. Completely hindered phenols have been shown to be powerful antioxidants of long life, but nonhindered phenols are not good antioxidants against light. The combination of an ultraviolet absorber with a hindered phenol gives excellent protection which is only fully developed when a little of the phenol has been oxidized to a colored compound. Many dithiocarbamates, dithiophosphates, and xanthates protect against light, but their effect is short‐lived except in the case of nickel and chromium isopropylxanthates. The peculiar stability of these materials is attributed to their acting as both ultraviolet absorbers and antioxidants. Since the addition of ultraviolet absorber to the nickel and chromium xanthates does not further increase their effectiveness, the combination of a hindered phenol and an ultraviolet absorber is the most potent protective agent against light for incorporation into translucent rubber vulcanizates.
X‐ray diffraction by hairs and feathers. Part I
Authors: Venkateswarlu K. , Pillai S. Padmanabha 
Published: April 2003

AbstractA study of the x‐ray diffraction of tail hairs of mammals, both domestic and wild, and feathers of birds has been made. The pattern due to buffalo hair is unique in the sense that about six Debye‐Scherrer rings have also been recorded in addition to the usual pattern of α‐keratin. The rings have been explained as due to crystallites in the fiber arranged at random about the fiber axis. The chromatographic record in the case of buffalo hair revealed the presence of a new amino acid. The d values have been calculated. The feather pattern resembles more that of β‐keratin. A comparison of the study of the hairs and the feathers has been attempted.
Light‐scattering measurements on solutions of natural and synthetic polyisoprenes
Authors: Allen P. W. , Bristow G. M. 
Published: April 2003

AbstractThe light‐scattering behavior of solutions of natural and synthetic cis‐1,4 polyisoprene is described. For milled natural rubber values of M̄w increase as the solvent power of the solvent is increased and, at the same time, the second virial coefficient tends to zero. These effects may be due to compact (e. g., branched) structures. With unmilled natural rubber there is evidence for the existence of microgel. Synthetic polyisoprene shows the behavior expected of a linear polymer.
Critical comparison of moving bar impact with gas expansion machines for dynamic loading of metals
Authors: Krafft J. M. 
Published: April 2003

AbstractAchievement of high head speed in a testing machine requires that two conditions be met: (1) a high velocity input to the machine, and (2) a reasonably high stiffness. The machines discussed here, while excelling in requirement (1) are characterized by a rather deficient stiffness. Because of this softness, the strain rate during a test will vary markedly with the amplitude and shape of the stress strain curve; indeed, so much so that it must be considered as a variable in the data. This paper gives an analysis of the motional characteristics of a typical gas‐pressurized testing machine. This machine is driven by a pressure source obtained from a chambered burning of gunpowder; head speeds up to 100 in./sec. are reached by a restricted expansion against a piston. It is found that observed strain rate vs. strain behavior can be predicted from the analysis by taking into account the decrease in driving pressure due to gas cooling and to its expansion, and the decrease in stiffness with strain in the specimen or stroke of the piston. Comparison of this type of machine with impact bar loaders previously developed at NRL shows a comparable degree of strain‐rate variation for both machines. However, with mild steel, the stress–strain data from the two machines can be correlated by considering instant strain rate as a variable.
The determination of surface properties of polymers from liquid drop stability on an inclined plane
Authors: Baer Eric , McLaughlin Thomas F. 
Published: April 2003

AbstractA method for studying the surfaces of solid polymers is described. Drops of various sizes were deposited on a horizontal surface; then the plane was tilted and the angles of inclination at which the drops begin to slide were recorded. A theory was developed which indicated that a plot of sin αs against V2/3− on linear graph paper should give a straight line. From the slope of the line, a constant K was obtained which characterized the surface. This constant is a function of the interfacial forces and the density of the drop. The critical surface tension for wetting Teflon (TFE) resin was found to be 20.5 dynes/cm. This is in close agreement with the critical surface tension determined by contact angle measurements. Alathon 23A polyethylene film which had been treated by electric corona discharge was studied. It was shown that K is related to the printability level, and that treated and untreated surfaces may readily be distinguished from one another by their K values.
The dry casting of viscose film
Authors: Price C. R. , Haskell V. C. 
Published: April 2003

AbstractRegenerated cellulose film prepared by a dry‐cast method has demonstrated outstanding superiority over similar film produced by the conventional wet‐cast process. Factors contributing to the superior quality of film prepared by the dry cast process are: (1) physical properties several times greater than for wet‐cast film of corresponding thickness; (2) high durability at conditions of low temperature and low humidity even without the addition of softening agents, and (3) outstanding dimensional stability when exposed to conditions of varying temperature and humidity. The dry‐cast cellophane differs structurally from the commercial product in having a lower degree of order, a lower degree of swelling in the gel form, and minor differences in molecular orientation. A commercial process for producing dry cast cellophane may be envisioned as a heated, polished support for drying the viscose film; a regenerating system of alcoholic hydrochloric acid, hot glycerine, or a hot, oxygenfree gas; a water both for purifying the film; and a conventional cellophane dryer. The ideal viscose composition for producing dry‐cast cellophane is high cellulose content, moderately high DP, sufficient degree of substitution on the cellulose to yield a high degree of dispersion, and low caustic content.
The effect of softeners on the elastic modulus of regenerated cellulose sheet
Authors: Hansen Orin C. , Marker Leon , Sweeting Orville J. 
Published: April 2003

AbstractThe dynamic elastic modulus of cellophanes has been measured by use of the resonant frequency of a 2 × 60‐mm. strip of film in longitudinal vibration. The niodulus was computed from the resonant frequency length of specinieii, and the cross‐sectional area determined from its resonant frequency in transverse vibration. The apparatus is described briefly. Unsoftened film and glycerol‐softened films containing 7.3, 13.7, and 21.3% glycerol prepared from the same roll of never‐dried regenerated cellulose were conditioned a t 75°F. and 15, 35, and 81% R. H., and the elastic moduli were measured in both directions. Moisture and softerier contents were determined. The reciprocals of the geometric means of the moduli in the machine and transverse directions were plotted as a function of the volume of film containing 1 g. of cellulose. The displacement of the curve obtained for each softened film from the curve for the unsoftened film measures the effect of the softener, since the curves would coincide if the effect of softener were from swelling only. This permits construction of an empirical equation for the modulus of these glycerol‐softened films as a function of moisture and softener content. It was found further that the logarithms of the corrected compliance (1/EV2/2c), where E is the geometric mean modulus and Vc is the volunie of film containing 1 g. of cellulose, gave a straight line when plotted as a function of the number of moles of water plus twice the number of glycerol present in 100 g. of cellulose. This indicates that the effect of a mole of glycerol in breaking up the hydrogen‐bonded structure of the cellulose is twice as great as that of a mole of water. These results have been compared with similar results obtained on films containing ethylene carbonate and ethylenediamine. With the exception of ethylenediamine‐treated films studied a t high humidities, these fdms gave points falling approvimately on the corrected compliance curve obtained for the glycerol‐softened and unsoftened films. For these films, however, the simple sums of moles of water plus moles of ethylene carbonate or ethylenediamine monohydrate present in 100 g. of cellulose were used rather than the weighted sum used for the glycerolsoftened films.
Adhesives in printed circuit applications
Authors: Rider D. K. 
Published: April 2003

AbstractThis paper discusses the technology of adhesives employed in printed circuitry. The chemical types of adhesives are described and their general characteristics are given. Typical printed circuit processes are used to spotlight the demands placed on the adhesives. Test methods and requirements peculiar to printed circuitry are discussed in detail, and particular emphasis is placed on those properties which will not be too obvious to the adhesives technologist unfamiliar with circuitry. Secondary applications of adhesives in printed circuitry are touched on briefly, and mention is made of bonding methods in use or under development which do not employ adhesives. Numerous literature references are given.
Progress report, task group on high speed testing, ASTM committee D‐20 on plastics
Authors: Patterson Gordon D. , Smith W. Reed 
Published: April 2003

AbstractInterlaboratory comparisons on several materials are being conducted among a half‐dozen laboratories having high speed tensile testers of widely different mechanical design and instrumentation. This progress report gives results from the first two round robins, the first on two plastic films and the second on copper wire. These materials were tested a t several speeds in the range of 1.3 to 130 m./min. (50 to 5000 in./min.). Preliminary conclusions and plans for future work are offered.
Estimating isothermal life from thermogravimetric data
Authors: Doyle C. D. 
Published: April 2003

AbstractEquations are given for estimating equivalent isothermal life from thermogravimetric data and for estimating the apparent activation energy for volatilization even though the nature of the kinetic process is unknown. Illustrative data for polytetrafluoroethylene are presented. The importance of using sample temperatures, rather than furnace temperatures, is noted.
Sign reversal of permselective membranes: A possible mechanism for neural conduction
Authors: De Kőrösy Francis 
Published: April 2003

AbstractAn electrochemical mechanism is sought for to explain the sudden transient change of potential across a nerve membrane during neural conduction. Ion‐permselective membranes change the sign of their permselectivity if the charge of their fixed ions is overcompensated for by highly charged counterions which become strongly bound to these fixed sites by electrostatic forces. Imagine a membrane with its sign thus reversed beyond a given borderline: cations could traverse on one side in the vicinity of this line and anions on the other, while no ions would traverse pure membrane faces themselves. Thus concentrations would be equalized at the borderline by passive diffusion, while the sign of membrane potential would change from one side to the other of the border. A mechanism for automatic propagation of the border along the membrane is suggested. Sign reversal of membranes can also be caused by covalent bonding of oppositely charged groups to a charged membrane site, for instance by esterification of a carboxyl group or of a phosphoric acid group of a lipoproteid nerve membrane with the amino alcohol choline. Hydrolysis of such an ester would cause the sign of the membrane to revert to its original direction. Such acetic sites and choline abound on nerve membranes, together with enzymes, which are known to split and synthesize choline esters. Their electrochemical function in neutral conduction might well be this changing of sign of membrane permselectivity.
A recording apparatus for the measurement of longitudinal creep
Authors: Scherr Henry J. , Palm William E. 
Published: April 2003

AbstractA recording apparatus for measuring longitudinal creep was developed to study viscoelastic properties of polymeric films. The heart of the apparatus is a photoelectric transducer that converts specimen extension and contraction into a voltage which is then applied to a millivolt recorder through a d.c. low‐drift amplifier. As used in this apparatus, the phototube detects the variable by having its photocathode surface shadowed by a movable mask. Supplementing the recording part of the apparatus is a mechanism for controlling specimen temperature. A polymer of plasticized polyvinyl chloride was studied, to demonstrate the applicability of the apparatus. The results obtained compared favorably with the method of visually observing the displacement with a cathetometer.
Temperature dependence of dynamic mechanical properties of mixed polymer systems. II
Authors: McIntyre A. D. 
Published: April 2003

AbstractThe temperature dependence at constant frequency of the viscous component E2(1/T) of the dynamic modulus has been determined for a homologous series of butadiene–acrylonitrile copolymers supported in a matrix of styrene homopolymer. The results, which agree with those reported earlier for a homologous series of butadiene–styrene copolymers, indicate that the transition temperature of a given plastic homopolymer, as measured from dynamic mechanical properties at essentially constant frequency in the range 200–300 cycles/sec., is depressed by the presence of a copolymerized rubbery diluent as the melting point of crystalline polymers is depressed by the presence of noncrystallizing comonomers. In addition, it has been found that the transition temperature is depressed by the presence of monomeric diluents much as the melting point of crystalline polymers is depressed by the presence of monomeric diluents. Two earlier assumptions, that the dynamic properties in the frequency range of interest should be independent of both the molecular weight of the rubbery copolymer and the degree of dispersion of the copolymer in the thermoplastic matrix, have been subjected to experimental scrutiny. The assumption regarding the dependence on molecular weight has been substantiated, at least for DP's in excess of 100. The assumption regarding the dependence on the degree of dispersion has been negated; the area under the E2(1/T) peak was found to be considerably greater for a coarse dispersion than for a fine one.
Raman and infrared spectra of 3‐methylbutene‐1
Authors: Ziomek Joseph S. , Forrette John E. 
Published: April 2003

AbstractInfrared and near‐infrared spectra of 3‐methylbutene‐1 were observed for the vapor phase at room temperature. Also, Raman displacements and depolarization factors of 3‐methylbutene‐1 in methanol and carbon tetrachloride were obtained at the same temperature. Tentative assignments of the observed Raman and infrared bands were made, and a classification of bands on the basis of group frequencies is given.
One‐step polyallylation of phenols
Authors: Aelony David 
Published: April 2003

AbstractA process for one‐step polyallylation of phenols was developed. Phenol is polyallylated in xylene in the presence of 3 moles of finely divided sodium hydroxide. Three moles of allyl chloride are added at such a rate as to maintain the reflux temperature at 110 to 120°C. Water is continuously azeotropically removed. The product contains allyl ethers of mono‐, di‐, and triallyl phenol. The bulk of the material is allyl ether of dially phenol which can be subjected to Claisen rearrangement followed by glycidyl ether formation and epoxidation of the glycidyl ether of triallyl phenol.