bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct-Reading Spectrographic Evaluation of Used Railroad Oils
Authors: Barth V. C.
Published: August 2009

In order to evaluate direct-reading spectrographic analysis for used railroad oils, a fuller understanding of the two types of spectrochemical analysis is helpful. The one method utilizes a photographic emulsion as the light integrating and measuring device. The light from the ignited oil sample is directed to a photographic plate which, upon development, and evaluated in terms of density, is related to the concentrations of the various elements. This device has now reached a high degree of perfection for quantitative analysis. Although its application will continue to expand, the sphere of activity is rather well defined and limited by the inherent properties of photographic emulsion. Because of these limitations, we found it necessary to consider other means of intensity measurement to realize the full capabilities of spectrochemical methods employing emission spectra. The latest direct-reading instruments, such as the Production Control Quantometer, employs multiplier phototubes instead of the photographic emulsion. Obviously, this high degree of precision readily lends itself to special techniques where extremely small amounts of elements are burned in the arc, as with the Rotrode method on used lubricating oil samples. In the multiplier phototube method, the diffracted light is picked up by the phototubes which change the light into current and amplify it up to a million times. This means that measurement of extremely small concentrations of an element is possible in a given lubricating oil sample. On the Production Control Quantometer, the current from the multiplier phototubes is fed to condensers, the charge of which is amplified by an electrometer amplifier, then fed to the Leeds & Northrup recorder where the apparent concentrations of the different elements in the sample are consecutively recorded in sequence. The apparent values on the recording chart must then be corrected to actual concentrations by means of a calculated chart.
Filtration of Diesel Engine Lubricating Oil
Authors: Earle Sherod L.
Published: August 2009

Qualification bench testing methods and requirements of a proposed military specification for Navy standard large full-flow lubricating oil filters are described. Typical test results with several brands of elements for flow rate pressure drop, filtering ability, resistance to shock, media migration, and differential pressure tests are presented. Failures observed with some elements during different tests are discussed and illustrated. A limited amount of data obtained during tests of a submarine engine and a high-speed diesel engine showed that full-flow filters provided good protection; high wear rates of some engine parts were reduced to satisfactory values. Under average engine conditions, element “life” is estimated to be 500 hr, or more.
Introductory Remarks
Authors: Klett R. A.
Published: August 2009

I am honored that it is my privilege to present to you this two-day symposium on the analysis of high-boiling petroleum oils, which has been prepared by Research Division IV of ASTM Committee D-2 on Petroleum Products and Lubricants under the sponsorship of the Division of Refining of the American Petroleum Inst. In the opinion of the Planning Committee, this symposium represents the first time that such a broad coverage by such an acknowledged group of authorities has been presented on this important subject. The interest in this topic is indicated by your attendance in such great numbers. Your presence lends prestige to this important undertaking and, might I say, cancels many of the apprehensive moments that I have had during the year and a half that it has taken to develop this program. Certainly, your presence and interest will be most gratifying to the men who have prepared the papers which are to be presented. Such an undertaking as this could not occur without the willingness of these men of knowledge and the cooperation of the organizations with which they are connected. It was the original thought of the committee that we should obtain the most authoritative information available on the subject of hydrocarbon types analysis of heavy oils. The authors of papers covering the many phases of analysis are the experts in their respective fields. The willingness of these scientists to expend their time and effort that we might gain from their knowledge is of great inspiration. Our appreciation is due them for their most important part and cooperation in making this meeting most meaningful to all of us.
Summary of Work of the American Petroleum Institute Research Project 6 on Hydrocarbons in the C13 to C38 Fraction of Petroleum
Authors: Mair Beveridge J. , Rossini Frederick D.
Published: August 2009

The light gas oil fraction, C13 to C17, of petroleum was separated into an aromatic portion and a paraffin-cycloparaffin portion. Four compounds, biphenyl at 255 C, 2,6-dimethylnaphthalene near 268 C, a trimethylnaphthalene near 288 C, and a dinuclear aromatic, C14H16, near 312 C, were isolated from the aromatic portion by regular and azeotropic distillation. The paraffin-cycloparaffin portion was separated by treatment with urea to give a concentrate of normal paraffins and a concentrate of branched paraffins plus cycloparaffins. Five normal paraffins, C13 to C17, were isolated from the normal paraffin concentrate by distillation. Distillation of the branched paraffin-cycloparaffin portion yielded portions of distillate in which certain groups of compounds, for example, the monomethylalkanes, were concentrated. The C18 to C25 fraction of petroleum, heavy gas oil and light lubricating oil, was separated into an aromatic portion and a paraffin-cycloparaffin portion by adsorption with silica gel. The aromatic portion was further separated by adsorption with alumina to give portions containing mononuclear, dinuclear, and trinuclear aromatics, respectively. The paraffin-cycloparaffin portion was further separated by treatment with urea to give a concentrate of normal paraffins and a concentrate of branched paraffins plus cycloparaffins. The portion containing the normal paraffins was fractionated by distillation at very low pressure, in a 50-stage apparatus, to give concentrates of the individual normal paraffin hydrocarbons. These were separately subjected to crystallization to yield purified samples of the individual normal paraffins, C18 to C24. A description of the 50-stage apparatus for distillation at very low pressures is included. The C26 to C38 fraction of petroleum was separated into four broad portions: a “water-white” oil portion, an “extract” oil portion, a “wax” portion, and a residue portion. The water-white oil portion was separated by distillation at very low pressures in a simple apparatus and then by solvent extraction with reflux in tall columns to give several series of “homogeneous” fractions. The extract oil portion was separated in a similar manner. Certain key fractions were carefully hydrogenated to convert the aromatic rings to cycloparaffin rings. The following properties were determined on all the important final fractions: molecular weight, content of carbon and hydrogen, content of sulfur, nitrogen, and oxygen, boiling point at a pressure of 1 mm of mercury, density, refractive index, refractive dispersion, kinematic viscosity at 100 and 210 F, aniline point, and optical rotation. Mass, infrared, and ultraviolet spectral data were obtained on certain selected fractions by a number of laboratories in the petroleum industry. The results were correlated to give information concerning the type and amounts of hydrocarbons in the lubricating oil portion of petroleum.
Determination of the Paraffin, Monocyclic, and Dicyclic Naphthene Contents of a Middle East Gas Oil by Selective Adsorption
Authors: Rampton H. C.
Published: August 2009

The effectiveness of selective adsorption on silica gel in separating the naphthene plus paraffin and the aromatic components of gasoline and kerosine fractions is well known. Numerous workers have employed the technique, outstanding among them being Mair and Rossini and their colleagues at the National Bureau of Standards, and more recently at the Carnegie Institute, Pittsburgh, Pa. In one communication by these investigators (1), the examination of a 230 to 300 C cut material from Ponca Crude was described, wherein the naphthene plus paraffin material first obtained was reprocessed over silica gel to yield an adsorptogram indicating a fair measure of separation between the naphthenes and the paraffins. In the present work a similar reprocessing technique has been used in the examination of a series of Middle East gas oil fractions in the boiling range 330 to 410 C.
Composition of an East Texas Lubricating Oil Distillate
Authors: Orkin B. A. , Bendoraitis J. G. , Brown B. , Williams R. H.
Published: August 2009

In recent years many investigators (1–4) have employed chromotography either alone or in conjunction with other separation processes in the analysis of petroleum fractions. Chromotography and distillation have been combined in this work in an effort to obtain relatively homogeneous fractions. Specific objectives were as follows: 1. The determination of the extent and type of separation achieved by these processes. 2. The evaluation of high molecular weight mass spectrometry in type analyses. 3. The characterization of the aromatic portion of a raw East Texas distillate lube oil stock and the furfural refined lube oil made from this stock. 4. The determination of aromatic types in seyeral lube oils made by varying degrees of hydrogenation of the raw stock. Many of the lube oil fractions and all of the hydrogenated oils were prepared in large enough quantity for oxidation studies (5). Correlation between composition and oxidation characteristics was studied. Due to the vastly greater importance of the aromatics in oxidation processes, the work so far has centered on that portion which is preferentially adsorbed on silica gel. This paper describes the methods used and the results obtained so far on the composition of an East Texas raw lube oil distillate, the corresponding furfural refined oil, and several hydrogenated compositions made from the raw oil.
The Separation of High-Boiling Petroleum Oils by Thermal Diffusion
Authors: Melpoldee F. W. , Sauer R. W. , Washall T. A.
Published: August 2009

Among the many laboratory processes in use today for the separation of heavy petroleum oils, thermal diffusion is recognized as a unique method of great future potentiality. Work to date by several investigators (1–3, 7, 9, 11, 12, 13) has demonstrated that remarkable separations can be achieved with relatively simple apparatus. It is believed that even more impressive use can be made of thermal diffusion with the development of more efficient apparatus and with a more thorough understanding of the basic principles of operation. There is also a need for a more practical determination of the mathematical relationships involved. In our laboratory the investigation of thermal diffusion has passed through several stages. The first was a study of a large number of mixtures of pure compounds, and the second involved separation and determination of the composition of a light and a medium lubricating oil. At present a critical evaluation is being made of column efficiency and methods for improving the degree of separation. The results of both the compositional study of lubricating oil and the study of efficiency of a multicolumn assembly are given below
Solution Behavior Patterns as a Supplement in Analysis of Oil Fractions
Authors: Derr E. L. , Deal C. H. , Pierotti G. J.
Published: August 2009

The accumulation of activity coefficients of model hydrocarbon solutes at infinite dilution in a wide range of solvents has led to a generalized correlation pattern of hydrocarbon solution behavior which should find increasing application in the interpretation and prediction of the results from solvent extraction or liquid-liquid partition chromatography. The pattern allows characterization of solvent environments for essentially any hydrocarbon solute in terms of five experimental infinite dilution activity coefficients. In principle, such characterization allows the independent pairing of any of these environments to give at least a hypothetical picture of how hydrocarbon solutes would be expected to distribute if the two environments were in fact in phase equilibrium. The independent choosing of solvent pairs can set up situations which allow maximum separation according to molecular weight of the solutes or maximum separation according to the types of solutes. It is believed the improved quantitative understanding of the factors involved in the extraction of broad fractions should be of considerable value in carrying out analytical separations of such oil fractions for either gaining direct information or the preparing of cuts for subsequent, more definitive analysis.
Determination of Methyl, Methylene, and Alkylbenzene Group Types by Infrared Absorption
Authors: Hughes Richard H. , Martin Robert J.
Published: August 2009

The first part of this paper describes the anomalies that appear in the determination of methyl, cyclopentyl and cyclohexyl methylene groups by previously published infrared group type methods. Serious discrepancies were found when these analyses were applied to polymers such as polypropylene and polybutene and also to compounds with different molecular weights than those used in the calibration. Previous workers have shown that methyl groups and the methyl part of ethyl groups on the side of a high molecular weight chain absorb more strongly at 7.25μ, the wavelength for the methyl determination, than do the end methyl groups on normal paraffins. An examination of extensive data on low molecular weight compounds shows the same behavior, pendant methyl groups absorbing more strongly at 7.25μ than do end methyl groups. By assuming that pendant methyl groups absorb approximately three times as strongly as do end methyl groups, the absorptions by polypropylene and high molecular weight compounds containing pendant methyl groups are reconciled with those of low molecular weight compounds. Pendant methyl groups also give anomalies in the short wavelength region. They absorb less at 3.38μ than do end groups, but they contribute more to the methylene absorption at 3.42μ than do end methyl groups. This anomalous behavior creates difficulties in the cyclopentyl and cyclohexyl methylene determinations at these short wavelengths. The second part of the paper discusses an investigation into the possibility of a group type analysis for the determination of the different types of alkyl substituted benzenes in a mixture of the types using the 10.0–15.0μ portion of the spectrum. A method has been developed whereby mono-substituted and ortho-, meta-, and para-di-substituted benzenes can be determined, but only with severe restrictions as to over-all sample composition. Tri- and higher substituted benzenes as well as polynuclear aromatics interfere with this scheme of analysis. These interferences severely limit the usefulness of the method, especially when applied to petroleum fractions. A table top integrator for use with previously recorded spectra from the Perkin-Elmer model 21 spectrometer was used in developing the group type analysis. It is described in some detail.
Analysis of Petroleum Oils by Mass Spectrometry
Authors: Carlson E. G. , O'Neal M. J.
Published: August 2009

A description is given of the routine mass spectrometric methods developed for the analysis of petroleum oils with emphasis on the determination of molecular weight distribution and hydrocarbon-type composition. In the development of these methods, the use of total ion intensity has proved useful for standardizing spectra to a constant charge volume and instrumental sensitivity. Since it is not possible to establish the absolute accuracy of the mass spectrometric methods, examples of internal consistency are given. Mass spectral evidence obtained in the development of the various methods has led to a simplified picture of the structural composition of petroleum oils.
Characterization of Hydrocarbons in Petroleum by Nuclear Magnetic Resonance Spectrometry
Authors: Williams R. B.
Published: August 2009

Analytical schemes are presented for characterizing saturate, aromatic, and olefinic fractions derived from petroleum, based upon high resolution nuclear magnetic resonance (NMR) measurements and generally, with the exception of the saturates, elemental analyses plus molecular weight. Saturates are characterized by a “branchiness index” (BI), which is defined as the ratio of the heights of NMR absorption bands due to methyl and methylene groups, respectively. The branchiness index correlates linearly with the naphthene ring carbon content in gas oil saturates from a variety of crude sources, which enables the latter to be determined from a NMR measurement. The scheme for aromatics analysis provides determinations of alkyl and aromatic ring carbon, the extent of alkyl group substitution on aromatic rings, the average number of aromatic rings per nucleus or per molecule, the number of carbons per alkyl group, and the structural group weight. To make these calculations it is necessary to estimate the carbonhydrogen weight ratio of the alkyl groups; this is assisted by a branchiness index measurement of the corresponding saturate fraction. The procedure also depends upon whether one assumes (for very high molecular weights) that aromatic nuclei in a molecule are directly joined or are separated by aliphatic chains. For the latter, an empirical expression depending upon probable average structures (obtained by correlation with mass spectrometer (MS) data) is used in the calculations. The olefin scheme depends in general upon similar types of measurements, but does not require correlative information. Analytical results on typical petroleum stocks are presented, and there is a discussion of sources of errors.
Adsorption and Physical Property Methods
Authors: Stout W. J. , King R. W. , Peterkin M. E. , Kurtz S. S.
Published: August 2009

The analysis of the viscous fractions of petroleum by physical property correlations, and other short cut methods, is a very fascinating one. This approach is very different from the complete separation used by API Research Project 6 (19). The American Petroleum Inst. project gives us basic information which can be used to check the rapid correlative methods. This paper briefly reviews the available rapid correlative methods for obtaining the composition of petroleum oils and provides a comparison showing how these methods work out when used on a group of 44 oils for which thorough analyses are available. These thorough analyses involve separation of the oil into its aromatic and saturated components by adsorption, and application of well-established correlations to the determination of the composition of the fractions. In recent years there has been a rapid increase in the use of carbon-type composition to describe the average composition of lubricating oil (8, 18). Carbon-type analysis reports the percentage of the total number of carbon atoms that occur in aromatic rings, per cent CA, naphthene rings, per cent CN, and paraffin chains, both free and combined, per cent CP. For example, Fig. 1 shows what may be considered a typical saturated lubricating oil molecule. It contains 31 carbon atoms, 13 of which are in naphthene rings. Therefore, per cent CN equals 42. It contains 18 carbons in paraffin chain structures. Therefore, per cent CP equals 58. Figure 2 shows a typical aromatic molecule which contains a total of 31 carbon atoms, including three aromatic rings and two naphthene rings. There are 14 carbons in aromatic structures; per cent CA therefore equals 45. There are 7 carbons in naphthene structures; per cent CN therefore equals 23. There are 10 carbons in paraffin chain structures; per cent CP therefore equals 32.
Comparison of Structural Group Analyses by Spectrometric and Physical Property Methods
Authors: Hastings S. H. , Johnson B. H. , Lumpkin H. E. , Williams R. B.
Published: August 2009

Recent advances in nuclear magnetic resonance and high molecular weight mass spectrometry have made it possible to obtain more detailed information on the composition of gas oils than has heretofore been available. The results obtainable by these techniques are discussed in other papers in this symposium and will not be reviewed in detail here. Because of the important position which catalytic cracking occupies in refining operations, and because of the need for more adequate feed characterization methods, it was believed desirable to examine a large number of catalytic cracking feed stocks (gas oils) by the two new methods. To assay the reliability of the new data, the results were compared on the basis of parameters determinable by other analytical methods. One such parameter is the sulfur content of the gas oil as determined by the Dietert method. Sulfur contents calculated from the mass spectrometer analyses generally agreed well with the observed sulfur contents. Comparisons of per cent CA (per cent of total carbon present in aromatic rings) and per cent CN (per cent of carbon present in naphthenic rings) with similar values obtained from available physical property correlations revealed certain discrepancies. Since the mass spectrometer and nuclear magnetic resonance values for CA showed excellent agreement, it was decided to investigate the validity of the various physical property methods by application to pure compounds. This is admittedly a severe test of correlation methods, but it served to uncover serious deficiencies and point the way to significant improvements. This paper summarizes the results of this study.
A Correlative Method for Structure of Solid Saturated Hydrocarbons
Authors: Rumberger G. G. , Dannenbrink R. W.
Published: August 2009

A number of the correlative methods for determining structure of liquid hydrocarbons are unsuitable for the solid saturated hydrocarbons present in petroleum waxes. In most cases, these methods employ correlation of physical property measurements made at 20 C, but suitable extrapolations are not available for use at higher temperatures. Furthermore, most of these require accurate measurements of molecular weight, and with solid hydrocarbons in the molecular weight range above 400 these have been difficult to obtain with sufficient accuracy (5, 6). In a recent study of the composition of microcrystalline waxes, it was desirable to have correlative methods which could employ relatively simple measurements at elevated temperatures to obtain an estimation of the approximate composition of isolated fractions and, if possible, learn something of the architecture and symmetry of the components. Recently Schiessler (1) has published criteria defining the limiting molecular structure of hydrocarbons which can be reacted with urea and thiourea to form clathrate compounds. Thus a given sample or fraction can be preliminarily classified. A scheme for this is shown in Fig. 1. Since the adducts of urea and thiourea can be easily decomposed to yield the reacting hydrocarbons, they can be further fractionated and examined to provide additional information. The procedure for removing aromatics from hydrocarbon mixtures by adsorbtion is well known. The method employed in this laboratory consists of dissolving each 100 g of sample in 1000 ml of isooctane and percolating through a 1-in. diameter column, 6 ft. long, packed with 700 g of 100 to 200 sieve Davison silica gel. This solution is followed with 700 ml of pure isooctane to displace the unadsorbed material. The filtrate is distilled to remove the isooctane, followed by steam and vacuum stripping. The adsorbed aromatics may be eluted by passing benzol or a benzol and alcohol mixture through the column.
Rubber and Its Environment
Authors: Haagen-Smit A. J.
Published: August 2009

Four hundred years have passed since explorers of South America found natives playing with peculiar bouncing balls and using unbreakable bottles, waterproof shoes, and cloth. Three hundred years later (1884) Goodyear took out a patent on the production of a superior quality of rubber by heating with sulfur. From then on there was an explosive expansion in the use and production of rubber which now runs into a million tons per year. In addition, a number of polymers have appeared on the market which help to satiate our hunger for rubber-type materials, and, through well-directed synthesis, the new compounds are endowed with properties accurately suited to the problem at hand (1). Although the manufacturer has a wide choice from natural and synthetic materials compounded in many various ways, there are always unfulfilled wishes, and this symposium deals with one of them. Rubber is an organic compound, and as such it is sensitive to a number of chemical influences— oxidation, reduction, and substitution —which readily break up the molecule or cause radical changes in the desirable properties of the rubber. In most cases, good judgment will determine where a particular rubber may be used. There is, however, one agent or, rather, a set of conditions to which all rubbers have to be exposed, namely, the atmosphere. Its components are not reacting violently with the rubber, but its slow attack is just as trouble-some. Some rubber compounds become tacky when exposed to the oxygen of the atmosphere. The addition of special inhibitors has overcome these unpleasant symptoms of degradation. Nevertheless, oxidation by molecular oxygen continues, although with greatly reduced rate. Just as the oils in paints slowly oxidize with a breakdown of the outer molecular layers, thereby losing their protective action, so does the rubber hydrocarbon lose its elastic properties through oxidation, resulting in a chalking of the surface. It is well established that olefin oxidation by molecular oxygen attacks the carbon atom adjacent to the double bond, forming hydro-peroxides and further oxidation products (2–4). These oxidations proceed at a considerable rate only after a certain induction period. There is experimental evidence that during the initial period peroxides are formed which catalyze further rapid uptake of oxygen. In order to prevent this buildup of peroxides, inhibitors such as phenols are added to the rubber, overcoming some of the bad features of the oxidizing effects. A special case of this oxidation is the effect of light, whereby numerous minute shallow cracks are formed. It is most likely that under the influence of the radiation radicals are formed which combine with the abundant supply of oxygen giving rise to chain-initiating radicals.
A Study of the Reaction of Ozone with Polybutadiene Rubbers
Authors: Erickson E. R. , Berntsen R. A. , Hill E. L. , Kusy Paul
Published: August 2009

All styrene-butadiene rubber (SBR) vulcanizates, when tested in a relaxed state, reacted with ozone (25 to 500 pphm (parts per hundred million) ozone in air) to form an oxidized film which provided an effective barrier against attack. SBR vulcanizates that were under stress, but which contained no effective antiozonant in their formulation, were readily attacked. The absorption of ozone began with an initial rate of zero but rapidly increased until a maximum rate had been reached when ozone cracks became visible. SBR vulcanizates that were under stress, but which contained an antiozonant, absorbed ozone with a high initial rate which depended on the concentration of the ozone-sensitive materials on the surface of the vulcanizate and on the partial pressure of the gaseous ozone. The rate of absorption declined during the exposure time until a steady low equilibrium rate was reached. The vulcanizates were protected from an attack by ozone (cracking) to a degree which ranged from poor to excellent, and depended (a) on the differential in the rates of reaction of ozone with the antiozonant and the rubber hydrocarbon, (b) on the initial concentration of the antiozonant at the surface of the vulcanizate, and (c) on the rate of effusion of fresh antiozonant from within the rubber to the outer surface of the oxidized barrier. A mechanism is proposed for the protective action of antiozonants in vulcanizates, and a rate equation has been derived from this mechanism which is consistent with the experimental data.
Comparison of Accelerated and Natural Tests for Ozone Resistance of Elastomers
Authors: Vacca G. N.
Published: August 2009

The destructive action of ozone on vulcanized rubber has been known for a long time. As far back as November, 1868, Samuel F. B. Morse complimented Austin Goodyear Day for his “Kerite” insulation because it had been found to resist the deteriorating effects of the ozone of the atmosphere (1) However, it was not until the publication of the work of Williams in 1926 (2) and that of Van Rossem and Talen in 1931 (3) that the role of ozone in the weathering of vulcanized rubber was clarified. These workers found that the multiple cracking which occurs on stretched rubber on outdoor exposure is caused by the ozone in the atmosphere and not by the effects of light. R. G. Newton (4) confirmed this conclusion in 1945. In 1946, Crabtree and Kemp (5) also confirmed the conclusion and later described an accelerated ozone weathering test for rubber (6). This method has been published as ASTM Method D 1149 and fundamentally involves exposure of specimens under stress to a controlled concentration of ozone in air at a definite temperature. This review is solely concerned with comparisons of ozone resistance found by such tests with that found by exposure outdoors. It is proposed to discuss accelerated and natural tests, compare results obtained in the two types of tests and then attempt to draw some conclusions.
Report on Interlaboratory Ozone Test Program of Astm Committee D-11, Subcommittee XV on Life Tests for Rubber Products, 1957
Authors: Veith A. G.
Published: August 2009

Early in 1957 a plan was outlined by the Ozone Test Section of Subcommittee XV of ASTM Committee D-11 on Rubber and Rubber-Like Materials for an Interlaboratory Test Program. This program's main objective was to determine the degree of variation that existed among laboratories with nominally identical ozone test chambers when testing specimens prepared and cured from a single rubber mix. There were also several secondary objectives. Since the advent of the first industrial ozone test chamber (Crabtree-Kemp), two later chambers have appeared. The first -was the Bush chamber and more recently the Mast chamber. Both of these feature the forced air circulation that has been demonstrated as necessary for valid and meaningful tests. Both of these chambers were included in this test program, and a comparison between the two is possible. This is one of the secondary objectives. Another objective was to determine how well various laboratories could maintain a given ozone concentration for a period of several days. In designing the testing program, a compromise had to be made between obtaining sufficient data for valid statistical interpretation and the need for keeping the testing load at a reasonable level. Some preliminary experimental work in these laboratories indicated that specimens with varying resistance to ozone attack would be valuable. It was decided that this could be best accomplished by employing different rubbers rather than by additives (antiozonants) added to a single rubber. Accordingly, SBR (GRS), neoprene, and butyl rubbers were selected. Typical formulations of these were prepared and used for testing.
Measurement with Phase and Interference Microscopes
Authors: Richards Oscar W.
Published: August 2009

Errors of measurement in visual microscopy are mentioned briefly. The phase microscope can measure the size of transparent specimens, is useful for counting and a good null method for the measurement of refractive index. Precautions necessary with absorbing specimens are discussed. The interference microscope can measure optical path in transparent and nearly transparent specimens and, from the path differences and refractive index, thickness and mass of reasonably homogeneous specimens may be calculated. The precision of the AO-Baker interference microscope is described, and errors of the instrument and the observer are discussed. An appendix summarizes the precision of thickness measurements of microscopical specimens, and a nomogram is included to aid computations.
The Electron Microscope in the Study of Minerals and Ceramics
Authors: Comer Joseph J.
Published: August 2009

During the past several years some very important advances in electron microscopy have been made in instrument design and performance as well as in specimen preparation techniques. The resulting improvement in resolution has opened up a new pattern of study, with greater emphasis now being placed on fine structural details which were not able to be resolved in earlier studies. With some of the new microscopes a resolving power as low as 8 Å can be obtained in direct observations of the specimen, while the lowest possible resolution with a replica technique is about 20 to 30 Å. The latter appears to be limited chiefly by the structure of the shadowing metals. With the development of a new replica technique made possible with Bradley's method of forming evaporated carbon films (1), particular attention is being paid to fine structure in clay minerals, glasses, and other ceramic materials. The examination of bulk clays has revealed details that are important in attempting to define the natural state of the mineral and has helped to provide logical explanations for some of the physical and chemical properties of importance when they are used as catalysts and in the manufacture of certain products in which clays play an important part. Surface details on glasses show fracture paths, liquid immiscibility, location and size of ucleating agents, weathering effects, and the effects of chemical surface treatments. In the study of ceramic bodies, electron micrographs of fractured specimens show how surface topography is related to particle size of the raw clay, the presence of impurities, and the firing temperature. This information has been helpful in basic studies of the formation of high-temperature phases in fired clays and has provided information on structural development which may be correlated with properties of the test specimens. Replica studies of other minerals have also been carried out, including studies of structure in crystals grown from solutions containing added impurities. Direct examinations of clays and other minerals are made for the determination of particle size distributions, the determination of the morphology of individual particles, or the determination of the state of aggregation of a specimen. The preparation of specimens for direct examination usually takes less time than that required for replica studies and under normal conditions permits the use of the ultimate resolving power of the instrument. By a simple selection of proper lenses, the electron microscope can now be converted readily for electron diffraction studies using an aperture system which permits one to “select” diffraction patterns from areas of over 30μ down to less than 2μ in diameter. One of its important uses is in the identification of small quantities of impurities in samples which by X-ray diffraction may appear to be “pure.” It is used also in the study of single crystals to obtain information on unit-cell parameters of compounds whose crystal size is so small as to preclude single crystal X-ray analysis.
The Structure of Synthetic Fibers
Authors: Scott Robert G.
Published: August 2009

This paper briefly reviews the techniques used in fiber microscopy and the types of information obtained. Special emphasis is placed on the problems of specimen preparation for electron microscopy. Two new techniques are described that minimize specimen distortion and allow one to use the full range of the instrument.
Microscopical Evaluation of Cotton Finishing Treatments
Authors: Rollins Mary L. , DeGruy Ines V. , Tripp Verne W. , Moore Anna T.
Published: August 2009

The laboratories of the textile industry expend considerable time and money attempting to improve wrinkle resistance of cotton fabrics. This paper defines the function of the microscopist in these research efforts which are directed both toward empirical formulation for commercial application and fundamental investigations of reaction mechanisms. After explaining the architecture of the cotton fiber which must be thoroughly understood for proper interpretation of microscopical phenomena, the authors turn to the different types of cotton finishing—purification of the fiber for removal of noncellulosic substances which prevent complete wetting and thereby subsequent processing, and physical modification of the fiber through treatment with chemicals which, by altering the crystalline structure of the fiber, permanently change its properties. The paper considers also additive finishing through coatings or impregnants which cause desirable modifications of yarns and fabrics, and finishing through chemical modification of the cellulose which produces new substances with entirely different chemical and physical properties but without changing the form of the fiber. The paper discusses techniques of staining, cross-sectioning, swelling and dissolution, and refractive index determination in optical microscopy and techniques of replication, fragmentation, ultrathin sectioning, and swelling and dissolution in specimen preparation for electron microscopy in the investigation of such treatments. It is supplemented by micrographs illustrative of optical and electron microscope observations.
The Why and How of Cable Oil Tests A Review
Authors: Blodgett R. B.
Published: August 2009

Tests on hydrocarbon oils for cable systems are reviewed on the basis of their ability to estimate the effect of an oil on six insulating properties: electrical strength, water sensitivity, thermal resistivity, bendability, loss factor, and susceptibility to corona in cavities; the sensitivity of an oil to oxidation, corona, and mixing with other oils; the fire, explosion, and personnel hazards involved in the use of an oil; and the continuity of oil production. To estimate the effect of a homogeneous hydrocarbon oil on insulation properties, viscosity and some measure of conductivity, preferably dissipation factor, are usually adequate. The desired level of viscosity may be either high or low depending on the cable system in which the oil is to be used. Conductivity should be as low as compatible with other desired properties. For some cable systems, gas content of an oil should also be low. The water content of clear cable oil is normally so low that its exact level is unimportant. Electrical strength measurements are useful mainly to establish the homogeneity of an oil sample. Sensitivity of an oil to oxidation or to mixing with other oils is best judged by conductivity measurements after a mild oxidation or after mixing with other oils. On the other hand, sensitivity to corona frequently can be adequately estimated by infrared or carbon-type analyses without a simulated corona test. Hazards in the use of an oil and the continuity of oil production can be estimated by measurements of flash point, explosibility limits, effects on animals, specific gravity, refractive index, and absorbance of ultraviolet and infrared energy.
Effect of Normal Aging on Strength of Glass-Fiber Reinforced-Plastic Honeycomb Cores
Authors: Marshall A. C.
Published: August 2009

The satisfactory service history of radomes made of reinforced-plastic materials obscures the fact that they suffer strength loss with age. Wide scatter in the scant test data available can be misleading, but such data can be made to yield significant information. They show, for example, that service life reduced the strength more than did shelf life. A method of simulating weather aging by exposure to 90 to 100 per cent relative humidity at 125 F for periods of one week to one month resulted in reasonably close duplication of in-service failures. Investigations of newly developed materials aged artificially indicate that their resistance to strength loss with aging is superior to that of older materials used in the failed radomes tested.
Effect of Natural Environment on Sandwich Structure with AMS 3722 Paper Honeycomb-Core
Authors: Zemer Robert F.
Published: August 2009

This paper summarizes a portion of the work completed in conjunction with the environmental test program, sponsored by ASTM Committee C-19 on Structural Sandwich Constructions. This program, known as Project Alpha, consisted of 3-yr exposures of a variety of types of sandwich construction and core materials at two separate test sites. The first of these locations provided a marine atmosphere. This was at the Kure Beach, N.C., 80-ft site where a natural environment included exposure to a salt-water atmosphere, direct rays of the sun, wind-driven sand and spray, and several seasons of hurricanes. The second site was located on typical farm land at State College, Pa. There, the rural environment was the normal weather of the northeastern United States, including exposure to sun, wind, rain, snow, and ice. This paper includes results of tests following 1-, 2-, and 3-yr exposure of six types of test panels manufactured using Aeronautical Material Specification (AMS) 3722 paper-honeycomb. This honeycomb core utilized for this project was 125 lb kraft paper with 35 per cent impregnation of phenolic resin, the core was expanded 20 to 1 during manufacture to give a cell size of approximately 0.455 in. A variety of sandwich facing materials were evaluated. The manufacturing methods used to fabricate the various types of sandwich panels are also described.
Effect of Climatic Variations on Polystyrene Foam-Core Sandwich Panels in Roofs and Walls
Authors: Edberg Edwin A.
Published: August 2009

A research program, conducted by Rennselaer Polytechnic Institute for Koppers Co., Inc., on the design and engineering of expanded polystyrenecore (Dylite) panels, proved conclusively prior to test reported here that structurally adequate panels can be designed. As an adjunct to this primary objective, the performance of panels in actual use in a structure exposed to climatic varations was considered to be of equal importance in predicting the long-term behavior and durability of this type of construction. By careful instrumentation, data on the long-term behavior of panels under normal use could be gathered and analyzed. Further, by using panels as load-bearing and non-load-bearing structural members with a variety of face materials, comparative data would be obtained on the relative merits of several common facings.
Experiences with Structural Sandwich in Building Construction
Authors: Biggs Richard A.
Published: August 2009

During the past 10 to 20 years many laminated panels have been used as wall elements in various types of building structures. In most cases, the panels support nothing but themselves. They offer varying resistance to wind loads, thermal transfer, sound transfer, fire, and weathering. Because of the variety of characteristics sought, plus the variety of exposure conditions to be met, no manufacturer has yet— to the author's knowledge—offered an all-purpose panel to the construction market. In the area covered in this paper (multistory buildings), sufficient difficulty has been encountered in the use of these panels to justify a review of some typical experiences in the hope that some of these common problems may be pinpointed and studied and a better solution developed. In the usual application of laminated panels in commercial or institutional buildings, the owner and architect are usually looking for long component life, minimal maintenance, design flexibility, thermal and fire resistance, and competitive price.
Introduction
Authors: Watson James F.
Published: August 2009

Owing to the increasing use of cryogenic propellants such as liquid oxygen and liquid hydrogen in missiles and space vehicles, the properties of high-strength structural materials at extremely low temperatures are becoming of prime importance to the national aerospace program. The papers in this symposium consider the mechanical properties of promising high-strength structural alloys at temperatures ranging down to −423 F. Papers pertaining to aluminum, magnesium, titanium, and stainless steel alloys are presented which treat most of the high-strength structural materials used at low temperatures in current and proposed missiles and space vehicles. The alloys reported upon were generally selected for study because they exhibited one or more of the following characteristics which suited them for missile and space vehicle application: high strength to density ratios; good toughness (that is, resistance to brittle fracture); adequate weldability; corrosion resistance; and good formability. In order to obtain optimum strength levels, the particular alloys selected for study were either cold worked (that is, cold rolled) or heat treated (for example, age hardened, or quenched and tempered) to their highest strength levels commensurate with adequate toughness. Since this symposium is aimed primarily at missile and space vehicle applications, attention was focused on sheet alloys since large cryogenic propellant tanks are fabricated from thin-gage sheet. In addition, since weldability is of prime importance for the pressure integrity of these tanks, the sheet alloys were reported upon in both the base metal and welded joint configurations whenever possible.
Some Mechanical Properties of Magnesium Alloys at Low Temperatures
Authors: Reed R. P. , Mikesell R. P. , Greeson R. L.
Published: August 2009

Magnesium alloys are approximately one fifth as dense as stainless steels, copper alloys, and nickel alloys, and two thirds as dense as aluminum alloys. Because they are light, it is desirable that some magnesium alloys be added to the growing list of cryogenic construction materials. For this reason, the mechanical properties in tension and impact of six representative magnesium alloys were tested at four temperatures: 300, 195, 76, and 20 K. The six alloys were sheet AZ31B-0, ZE10A-H11 and H10, HM-21A-T8, and HK31A-0; sand-cast HX-31A-T6; and extruded HM31A-F. Both macrophotographs and microphotographs were taken to indicate deformation and fracture characteristics.
Sharp-Edge-Notch Tensile Characteristics of Several High-Strength Titanium Sheet Alloys at Room and Cryogenic Temperatures
Authors: Espey G. B. , Jones M. H. , Brown W. F.
Published: August 2009

The 1-in. wide sharp edge notch tensile test was used to establish the notch sensitivity of several titanium sheet alloys including those of interest in the DOD Titanium Alloy Sheet Rolling Program. The influence of aging temperature was investigated in room-temperature tests and selected alloy conditions were also evaluated at −320 and −423 F. Room-temperature notch sensitivity develops with the aging reaction being most pronounced for the fully aged conditions and decreasing with overaging. A considerable reduction in notch sensitivity in some alloys can be obtained by overaging with relatively small loss in yield strength. At tensile strength to density ratios below about 1,000,000, the best ferritic steels known to the authors have notch sensitivities essentially equal to the poorest of the titanium alloys investigated. At higher strength to density values, the superiority of the titanium alloys rapidly increases. However, it should be noted that the strongest conditions of the titanium alloys possess fracture toughness, KC2, values sufficiently low that careful attention must be given to elimination of flaws in highly stressed components. At cryogenic temperatures, the titanium alloys exhibited higher notch sensitivity than alloys now normally employed for light weight cryogenic tankage. However, the −320 F and −423 F yield strength to density ratios of the commonly used materials are from 40 to 50 per cent lower than obtainable from titanium alloys. The elongation for several of the investigated titanium alloys exhibited a sharp drop between −320 F and −423 F. However, an equally sharp transition in the notch properties did not occur in this temperature range.