Showing papers in "Journal of research of the National Bureau of Standards in 1948"
TL;DR: The available thermal data for H2, HD, and D2 in solid, liquid, and gaseous states have been brought together, including the distinctive properties of ortho and para forms of H2 and D1 and numerous equations are presented.
Abstract: New developments in science and industry are aided by accurate knowledge of the behavior of important substances. The great abundance of chemical processes and comX pounds in which hydrogen is involved make it of particular interest. The experimental and derived data presented here for hydrogen extend over a large range of temperature. Low temperatures are required for the liquid and solid, and moderate and high temperatures occur in chemical reactions. The available thermal data for H2, HD, and D2 in solid, liquid, and gaseous states have been brought together, including the distinctive properties of ortho and para forms of H2 and D2. Some data not previously published have been added. The thermal data include thermodynamic functions for the ideal gas state, equilibrium constants, data of state, viscosity, and thermal conductivity with dependence on the pressure, vapor pressure* solid-liquid equilibria, specific heats, and latent heats. Values of state derivatives useful in thermodynamic calculations have been given for normal hydrogen, and. the related differences between thermodynamic functions for real and ideal gas states have been evaluatedA temperature entropy diagram for normal H2 in the range of experimental data is also given. The compiled thermal properties of hydrogen are presented in 38 tables, 33 graphs, and numerous equations. The sources of the data have been given in an extensive bibliography.
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TL;DR: In this article, a new crystal form of manganosic oxide (M113O4), stable above 1,170° C, w^s found to be cubic of spinel structure.
Abstract: Past work on the modifications of manganese dioxide of interest in dry-cell manufacture is reviewed. New X-ray data, at both room and elevated temperatures, combined with differential heating curves lead to the conclusion that five types of manganese dioxide exist: (1) well-crystallized pyrolusite; (2) gamma manganese dioxide, a poorly crystallized pyrolusite; (3) ramsdellite; (4) cryptomelane, a form containing essential potassium or sodium; and (5) delta manganese dioxide, believed to be a poorly crystallized cryptomelane. The high-temperature X-ray diffraction data indicated the phase changes that cause the heatingcurve effects. A new crystal form of manganosic oxide (M113O4), stable above 1,170° C, w^s found to be cubic of spinel structure. Fineness determinations by both the nitrogen adsorption and the X-ray line broadening methods were made on selected samples.
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TL;DR: The application of the mass spectrometer to the study of the thermal decomposition of polymers is described and a quantitative treatment relating the compositions of certain coploymers and the yields of monomers is given.
Abstract: The application of the mass spectrometer to the study of the thermal decomposition of polymers is described. The relationships between the structure of polymers and yield of monomers on decomposition are discussed. A quantitative treatment relating the compositions of certain coploymers and the yields of monomers is given. Data are presented showing the composition of the volatile hydrocarbons produced by the thermal decomposition of several vinyl and diene polymers.
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TL;DR: A method based on the Unterzaucher procedure has been developed for the determination of small amounts of oxygen in organic compounds using a liquid-air or potassium-hydroxide gel.
Abstract: A method based on the Unterzaucher procedure has been d eveloped for the determination of small amounts of oxygen in organic compounds. The method involves t he p yrolysis of the sample in an a tmosphere of helium, conversion of the oxygen compounds tha t are form ed to carbon monoxide by passage of t he products over pellets of carbon at a t empera ture of 1120° C and collection of t he carbon monoxid e in a flask of known vo lume. In terfering s~lbs tan c~s are removed by passage of t he gas through a liquid-air or potassium-hydroxide t rap before collec tion of t he gas. The percentage of carbon m onoxide in t he collected gas is determined t hrough use of t he N BS col orimetric indicating gel. As li ttle as 0.01 percen t of oxygen can be determined readily .
33 citations
TL;DR: In this paper, the design, construction, and measurement of a group of small primary and secondary standards of capacitance for this purpose are described, the values of which range from 0.001 to 5.0 micromicrofarads.
Abstract: In the measurement of small capacitances, such as the interelectrode capacitance of vacuum tubes, standards are needed for checking the calibration of the measuring equipment. The design, construction, and measurement of a group of small primary and secondary standards of capacitance for this purpose are described, the values of which range from 0.001 to 5.0 micromicrofarads. Capacitators of 0.1 fi/xf and above are of the Kelvin guard-ring type; those of 0.1 fifif and smaller are of a new "guard-well" type, which permits the construction of primary standards for values as low as desired.
TL;DR: In this article, a grating spectrometer with a PbS cell for detector has been used for the measurement of the infrared absorption bands of methane in the region of 1.66 /-t.
Abstract: A grating spectrometer with a PbS cell for detector has been used for the measurement of the infrared absorption bands of methane in the region of 1.66 /-t. Many lines of the P, 0, and R branches of the 1.66-ju band have been observed. These are well resolved and are of the correct structure and spacing for the F2 component of 2 vz. The lines for values of / up to 10 are sharp^ showing no indication of splitting due to interaction with neighboring states or to centrifugal distortion. The rotational constants obtained for this band are B' = 5.178, £3 = 0.0346. The latter value is lower than in the vz fundamental. Other bands observed are more, complex and irregular, presumably due to mutual interaction.
TL;DR: The second dissociation constant of oxali c acid was determined at interval s of 5 degrees from 0° to 50° C by measurement of the electromotive force of cells without liquid junction as mentioned in this paper.
Abstract: The second dissociation constant of oxali c acid was determined at interval s of 5 degrees from 0° to 50° C by measurement of the electromotive force of cells without liquid junction . Hydrogen a nd sil versil ver-ch loride electrodes were employed . The so l u t ions were composed of potass ium binoxalate, sod ium oxalate, and sod ium ch loride. The value of the second dissoc iation con tant , 1(2, in t he temperatu re range st udied is given by the equation
TL;DR: In this article, a series of measurements were made of the return of resistance in superconducting wires when the current was increased up to and beyond the critical value, and the results were discussed in the light of Landau's theory of the intermediate state.
Abstract: A series of measurements was made of the return of resistance in superconducting wires when the current was increased up to and beyond the critical value. Wires of pure indium of three different diameters were used, and measurements were made on each wire at four different temperatures. The transition curves for a wire of given diameter were reproducible and were independent of temperature. Measurements on sections of wire 0.6 millimeter long gave substantially the same results as measurements on long wires. The fraction of the normal resistance restored by the critical current varied from 0.77 for a wire 0.36 millimeter in diameter to 0.85 for wires 0.11 millimeter in diameter. The classical formula predicts a value of 0.50. The results are discussed in the light of Landau's theory of the intermediate state, and it is shown that the classical value may be approached for wires of large diameter.
TL;DR: Preliminary measurements in Germany showed that the TlBr-I crystal has a high index of refraction in the visible and the infrared regions and that in thickne..;ses of 2 mm it is transparent beyond 40J.
Abstract: Some of the optical properties of the thallium halides have been known for a considerable time. The residual rays of some of these substances were measured by Rubens and \",Vartenberg 1 in 1914. The maxima of the refl ection bands were 9l.9 !L for TICI, 117 !L for TlBr, and 152 J.l. for TIl. These reflection maxima fall in thclongw\"avelength region of the infrared. This fact indicated that the absorption of the material, ould not be intense for modcrate thicknesses to about 40 0(' 50 J.l.. Thallium iodide does not form cubic crystals and usually eAi sts a a powder. In order to use it for infrared studi es, a mixed crystal with TlBr from the fused mixture is grown . During the war such mixed crystals were grown in Jena. The material was called KRS5 and consisted of about 42 percent of TlBr and 58 percent of TIl. A mixed crystal of TICI and TlBr was called KRS6 and other materials that were used in the infrared region were also included in the KRS series. The KRS5 is highly resistant to water and was found useful on field instruments. Preliminary measurements in Germany showed that the TlBr-I crystal has a high index of refraction in the visible and the infrared regions and that in thickne..;ses of 2 mm it is transparent beyond 40J.l.. In 1945 plans were made at Fort Belvoir and at the Nation al Bureau of Standards for the growing of synthetic crystals of the thallium
TL;DR: In this article, a study of the action of boron in relation to the hardenability of high-purity alloys varying in carbon content was made, and it was shown that the effect of the carbon content on the hardness of these alloys and certain steels is due to its action in retarding; the rate of nucleation of ferrite and carbide while in solid solution in austenite.
Abstract: A study was made of the action of boron in relation to the hardenability of high-purity alloys varying in carbon content. The effectiveness of boron in enhancing the hardenability of these alloys and certain steels is believed to be due to its action in retarding; the rate of nucleation of ferrite and carbide while in solid solution in austenite. The hardenability of the boron-treated alloys, as determined in terms of the critical cooling rate of small specimens austenitized at a wide range of temperatures, varied with the prior history and with the carbon content. The hardenability of a commercial boron-treated steel, as determined by the end-quench test, was also sensitive to prior thermal treatments. Boron was lost in the decarburized zone of commercial steels, and its rate of diffusion apparently is of the same order of magnitude as that of carbon. The heat treatment of specimens of the alloys and steels to produce a boron constituent and the microstructures of the alloys as cast and as homogenized are described.
TL;DR: By the use of instruments with good resolution and by detecting with pho tographic plates that average out the fluctuations of the flame, many band systems have been identified and the spectra of such atomic groups as OH, ON, NO, OH , and NH are not observed in the infrared region.
Abstract: Many observers have studied th e infrared emi sion of a Bunsen flame [11. 2 The strongest band ocem s at about 4.4 Il and is produced by carbon dioxid e. Other bands have been found a t 0.95, 1.45, 2.0, and 2.8 Il , and are a ttributed to carbon dioxide and water vapor. Very little radiation has been observed in the region beyond 7 Il . In the visible and ultraviolet regions of the spectrum, considerahle progress has been made in the study of flames [21. By the use of instruments with good resolution and by detecting with pho tographic plates that average out the fluctuations of the flame, many band systems have been identified . The band systems include such atomic groups as OH, ON, NO, OH , and NH. The ques tion may be asked why the spectra of such groups have not been 'observed in the infrared region. The probable reason is tha t sufficiently high resolution has not been applied in the infrared region to separate properly the spectra of the different groups. Also, slight fluctuations in the flames make i t difficult to obtain accura te meas-
TL;DR: In this article, the coefficients of cubical expansion of 10 tannages of leather and tendon collagen have been measured by using water as the confining liquid, and the results, calculated for dry leather of density 1.560 g/ml, show that an average coefficient of 540X10~/°C applies for collagen and all leathers except chrome-vegetable leather.
Abstract: The coefficients of cubical expansion of 10 tannages of leather and tendon collagen have been measured by using water as the confining liquid. The results, calculated for dry leather of density 1.560 g/ml, show that an average coefficient of 540X10~/°C applies for collagen and all leathers except chrome-vegetable leather, the coefficient of this tannage being 340X 10~/°C. These averages have a reproducibility indicated by standard deviations of 13X10-/°C and 37X10-/°C, respectively. The "shrinkage" or transition temperature is a band rather than a sharp point on the temperature scale. During apparent shrinkage, an increase in real volume of approximately 1 percent occurs. This increase in volume is irreversible, but the thermal expansion below the transition range is nearly completely reversible. The rate of expansion during transition of collagen follows the law of a firstorder reaction. The results are interpreted as indicating that the shrinkage does not occur at a characteristic temperature but is a rate process. The transition may be pictured as a change of state possibly coupled with a reaction.
TL;DR: Measurements have been made to determine the density and refractive indices of lactose solutions to help the investigator working with pure solutions as well as to the analyst dealing with solutions in which the total solids may be calculated as lactose.
Abstract: Lactose, the disaccharide commonly known as milk sugar, has for many years been of commercial importance. Until recently its principal use was in the manufacture of pharmaceuticals, food products, and in the preparation of modified diets; however, the penicillium industry now also requires large quantities of this sugar. In the present investigation measurements have been made to determine the density and refractive indices of lactose solutions. The tables here presented are expected to be of use to the investigator working with pure solutions as well as to the analyst dealing with solutions in which the total solids may be calculated as lactose.
TL;DR: The infrared emission spectra of a hydrogen flame and of a natural gas flame have been compared in the region from 1.7p to 24p as mentioned in this paper, where the rotational lines became more intense as the temperature of the flame was increased.
Abstract: The infrared emission spectra of a hydrogen flame and' of a natural gas flame have been compared in the region from 1. 7p. to 24p.. Emission bands have been observed at 1.87p., 2.78p. , 4.37p., 6.20p., and 15p. that a re produced by molecules of H 20 and CO2• Another band at 3.316p. is attributed to methane. From 3.0p. to 3.8p. there are a number of rotational lines, some of which may be produced by OH and others by H 20 molecules. As the temperature of the flame was increased, the rotational lines became more intense. Five lines in the region from 3.4p. to 3.8p. agree clo ely in posit ion with the predicterl rotational lines of tbe P branch of the 2-->1 vibrational band of OH. These lines correspond to values of [( equal to 11, 12, 13, 14, and 15. Wave numbers of some of the observed rotational lines were found to show a good correspondence with predicted values for K equal to 11 tv 36, for lines extending from 9p. to 24p.. I n addi tion to this series of lines, t here are other lines that are produccd by the rotational states of H 20 molecu le. A discussion i included of t he various methods of observing name spectra.
TL;DR: In this paper, a simplified method for making shadowed thermoplastic negative replicas of fibrous materials was developed and fine details of the morphology of the wool fiber, before and after treatment, were clearly revealed by the electron microscope.
Abstract: A simplified method for making shadowed thermoplastic negative replicas of fibrous materials was developed. Through this technique, fine details of the morphology of the wool fiber, before and after treatment, were clearly revealed by the electron microscope. The structural implications of the electron micrographs are discussed with respect to the subject of wear and in reference to the observations of other investigators.
TL;DR: In this article, the dielectric constants of dilute benzene and dioxane solutions of primary, secondary, and tertiary amine salts of picric acid were measured, and the effect of the size and shape of the alkylammonium ion and of hydrogen bonding on the association were discussed.
Abstract: The dielectric constants of dilute benzene and dioxane solutions of primary, secondary, and tertiary amine salts of picric acid were measured. Dipole moments are reported for the picrates of the following amines; in benzene: tri-wo-amyl-(11.9), tri-n-butyl-(11.9), triethyl(11.7), diethylbenzyl(11.8), di-n-butyl(11.5), di-w-propyl(11.5); in dioxane: tri-n-butyl(12.2), di-n-butyl(12.1), n-octyl(12.1), and rc-octadecyl(12.3). The picrates of primary and secondary amines show a pronounced tendenc} to associate in benzene, as evidenced by the nonlinear variation in dielectric constant with concentration, but not in dioxane. The effect of the size and shape of the alkylammonium ion and of hydrogen bonding on the association are discussed.
TL;DR: In this article, methods of preparation, optical properties, and X-ray diffraction data are reported for six barium aluminate hydrates, three of which are obtained successively by precipitation from supersaturated barium alumininate solutions at 30° C. The first, designated by the empirical formula l.lBaO.Al2O3.6H2O, is metastable with respect to the second, lBaO 3.4H 2O.
Abstract: Methods of preparation, optical properties, and X-ray diffraction data are reported for six barium aluminate hydrates. Three of these were obtained successively by precipitation from supersaturated barium aluminate solutions at 30° C. The first, designated by the empirical formula l.lBaO.Al2O3.6H2O, is metastable with respect to the second, BaO.Al2O3.7H2O, which in turn is metastable with respect to BaO.Al2O3.4H2O. Two lower hydrates, BaO.Al2O3.2H2O and BaO.Al2O3.H2O, were prepared hydrothermally. 2BaO.Al2O3.5H2O was obtained from boiling barium aluminate solutions.
TL;DR: In this article, a simple method of controlling the integrated exposure of the fluctuating arc lamps used in the textile and other industries for testing lightfastness of textile dyeings and stability toward light of materials in general, is described.
Abstract: A simple method of control of the integrated exposure of the fluctuating arc lamps used in the textile and other industries for testing lightfastness of textile dyeings and stability toward light of materials in general, is described. A piece of light-sensitive paper is placed in lamps along with materials to be tested, and the exposure is terminated when a match with a standard, observable with the unaided eye, is obtained. The standard is a strip of the same batch of paper that has been exposed in a master lamp to a definite light dosage. The method is based upon standard light quantities and is thus largely independent of variation between batches of light-sensitive paper. The variations among fading lamps used in the textile industry and the causes, such as differences in lamp models, and line voltage, are discussed. A 4-percent difference in line voltage leads to a difference in radiant output of 11 percent in the waveband from 300 to 480 millimicrons, the region probably causing most of the fading of dyed textiles. Variations in line voltage considerably larger than 4 percent are probable in many communities. The papers were made in batches of 20 to 30 thousand test pieces by dip-dyeing special cotton-rag or wood-fibers papers with aqueous solutions of Niagara Blue G, or with Victoria Blue B in aqueous ethanol. One paper was made by beater-dyeing wood fibers with Niagara Blue G to give a nonleaching paper and was sized with melamine resin to impart high wet strength, making the paper suitable for lamps with water spray. Other paper-dye combinations were studied. Data are presented indicating the visual sensitivity of the various types of papers from 1 to 100 hours of usual arc exposure, the permanence of the papers during storage in the dark, the uniformity throughout each batch, and the effect of nonuniformity, temperature effect, lasting qualities of the standard strips during use, correlation with textile dyeings, and the effect of intermittent exposure. The master lamp used for standardizing the papers, its accessories, and reproducibility of input power and radiant output are discussed.
TL;DR: In this article, a general formulation of the transducer concept and the conditions which underlie the technique of the application of network equations to wave-guide problems is presented, guided by a formulation of what may be called the transducers concept, according to which, essentially, a transducers is a power transfer device which is to be described only in terms of external characteristics.
Abstract: A systematic and general formulation of the concepts and the conditions which underlie the technique of the application of network equations to wave¬ guide problems is presented. The discussion is guided by a formulation of what may be called the transducer concept, according to which, essentially, a transducer is a power-transfer device which is to be described only in terms of external characteristics. Waveguide and circuit devices are con¬ sidered as transducers whose terminal phenomena are electromagnetic fields varying harmonically with time. The basic task is then the definition of suitable terminal variables characterizing the terminal fields. The con¬ struction of variables of this kind for waveguide transducers is discussed in considerable detail; for circuits, for which suitable variables are voltage and current, the construction is sketched. Transducer theory is defined, discussed, and illustrated by the development of selected relations of the theory, and is shown to coincide with much of what is generally connoted by \"theory of four-terminal networks\". As a matter of interest and importance in applications of the technique, derivations of a rather general reciprocity theorem and of a version of Foster’s reactance theorem are included. Both theorems apply to both wave¬ guide and circuit structures.
TL;DR: This paper, the second in a series concerning the use of indicator dyes to study the reactions of organic acids and bases in organic solvents, deals with halogen derivatives of phenolsulfonephthalein.
Abstract: This paper, the second in a series concerning the use of indicator dyes to study the reactions of organic acids and bases in organic solvents, deals with halogen derivatives of phenolsulfonephthalein. Spectrophotometric data are given for mixtures of bromocresol green, bromophenol blue, iodophenol blue, and tetrabromophenol blue with primary, secondary, and tertiary aliphatic amines in benzene; and qualitative data are tabulated for chlorophenol blue, bromochlorophenol blue, chlorophenol red, bromophenol red, bromocresol purple, and bromothymol blue. Comparisons are made of the phenolsulfonephthaleins and the bromophthalein magentas. The structural changes that accompany the color phenomena are discussed. Suggestions are made regarding the use of the indicators in inert solvents.