bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF MAJOR AND SOME MINOR CONSTITUENTS ON GLASSMELTING*
Authors: Enright Dorothy P. , Marshall Paul A. , Poole James P. 
Published: October 2006

AbstractThe effects of the major and some minor constituents on the melting and fining characteristics of amber and flint container glasses are discussed. The constituents investigated were silica, alumina, lime, magnesia, soda, fluorine, barium oxide, and sulfates. The effects were measured by seed count, visual analysis, and low‐temperature viscosity. Curves of fining time and low‐temperature viscosity characteristics are presented
SURFACE STRUCTURE AND SURFACE PROPERTIES OF CRYSTALS AND GLASSES*
Authors: Weyl W. A. 
Published: October 2006

AbstractExperiments concerning the influence of asymmetrical units on the surface properties of glasses, sponsored by the Mechanics and Materials Branch of the Office of Naval Research, led to a better understanding of the surface structure of crystalline solids A picture is advanced which indicates a close similarity between the atomic structure of the surface layer of a crystal and that of a glass. Common to both are certain characteristic features, namely, the inconstancy of (a) the coordination number, (b) the inter‐nuclear distances, and (c) the bond angles.The difference between the surface structure and the interior of a crystal depends on the polarization properties of the ions A schematic representation of the distribution of bond strength in ideal and real crystals, in glasses, and in surface films brings out the similarity between the surface of crystals and the structure of glasses.Based on this picture, a number of apparently unrelated phenomena are discussed and explained: (1) devitrification of the glass surface, (2) effect of imperfections on the transformation of crystals (silica brick), (3) sinteririg of highly refractory oxides. (4) dielectric constant of polycrystalline materials, and (5) electric absorption of stratified dielectrics
BEHAVIOR OF FIRED‐CLAY RING SECTIONS UNDER LOAD*
Authors: Everhart J. O. 
Published: October 2006

AbstractThe advent of the electric strain gauge has made it possible to study the behavior of ceramic materials under load, and their stress‐strain relations may be determined with exactness. Earlier work by Lassettre and Everhart has shown that ceramic materials are elastic and that mathematical and engineering formulas may be applied to their use. This paper is concerned with the theoretical analysis of stresses in ring sections and with the behavior of fired ceramic ring sections, such as sewer pipe and drain tile, under stress.Data are presented which show that fried ceramic pipe almost precisely follow the behavior predicted from theoretical calculations such as those first presented by Talbot in 1908. A new precise equation for calculating relations between diameter, wall thickness, and strain is presented, and the validity of shorter semiempirical formulas commonly used is examined in the light of the more precise knowledge. Examples of the use of these mathematical formulas for changing relationships between diameter and wall thickness are given. Some manufacturers of sewer pipe have already changed their dies to give the different relationships, with successful results.
DEVELOPMENT OF A PORCELAIN VACUUM TUBE*
Authors: Hursh R. K. 
Published: October 2006

AbstractA satisfactory vacuum tube for the betatron was produced from porcelain by the casting process. The tube is toroidal in form with two tubular arms to which glass connections are fused for the sealed‐in electrical leads. The interior of the tube has a metallic electrically conductive coating. The tube is permanently sealed off with a high vacuum.
HYGROSCOPICITY OF SODA‐LIME‐SILICA CONTAINER GLASSES*
Authors: Matson Frederick R. 
Published: October 2006

AbstractPowdered‐glass samples were exposed to an atmosphere of 98% relative humidity at 100°F. for three days. Commercial bottles and laboratory melts which systematically covered the field of container compositions were tested. The resulting gain in weight of the glasses, which is a function of their chemical compositions, can serve as an accelerated test of the rate of attack by water vapor. The determination of the permanent gain in weight of the treated samples after they have been dried and the appearance of the products formed on the surface of the glass powders provide further useful data.
SOME EFFECTS OF ZINC AND CARBON MONOXIDE ON FIRE‐CLAY REFRACTORIES*
Authors: Patrick R. F. , Sosman R. B. 
Published: October 2006

AbstractNo experimental proof could be obtained that zinc has any disintegrating action on blast‐furnace fire‐clay brick. Zinc and zinc oxide, however, act as mild catalysts for the decomposition of carbon monoxide to form carbon dioxide and carbon, a reaction which has been abundantly proved, when catalyzed by iron, to be a prime cause of disintegration of fire‐clay brick. The carbon deposited by the reaction is crystalline graphite.
CRYSTALLOGRAPHIC INVERSIONS OF THE ALUMINUM ORTHOPHOSPHATE POLYMORPHS AND THEIR RELATION TO THOSE OF SILICA*
Authors: Beck Warren R. 
Published: October 2006

AbstractThe temperature‐stability relationships of the AlPO, polyrnorphs have been studied by X ray, thermal analysis, and thermal expansion. The system parallels that of silica very closely. Following is a diagrammatic representation of the findings for AlPO4: Conversions from one form to another are shown to be much more rapid than for corresponding silica cases. Furthermore, the temperatures, with the exception of the berlinite inversion. are all lower than for corresponding silica temperatures.
PHOSPHATE GLASS: PbO‐WO3‐P2O5 SYSTEM*
Authors: Rothermel Joseph J. , Sun Kuan‐Han , Silverman Alexander 
Published: October 2006

AbstractThe glass‐formation region has been determined for the PbO–WO3–P2O5 system ‡ and certain physical properties of representative glasses have been measured. Glasses of the system show an unusually high X‐ray and gamma‐ray absorption and are not readily discolored when exposed to X rays. Equations have been developed from which specific volumes and lead equivalents may be calculated from composition. Because of their high index of refraction and relatively low dispersion these glasses are also useful for optical purposes.
SPOT TEST FOR CHEMICAL RESISTANCE OF ENAMELED SURFACES*
Authors: Roberts J. T. 
Published: October 2006

AbstractA theoretical relationship between the color and thickness of thin films of amorphous silica was established. An acid‐resistance test based on this relationship was developed and applied in the testing of enamelware.According to the results obtained thus far, the color changes that are actually brought about by chemical attack agree with those which should occur theoretically. The test method thus appears to be fundamentally sound, at least insofar as this point is concerned.Its application in the testing of an enamel at different temperatures, as well as in the testing of various types of enamels at constant temperature, appears to afford satisfactory results. Enamel No. 41, when exposed for 48 hours to a solution of 20% hydrochloric acid at 60°F., developed according to this method of test a film about 675 a.u. thick. At 100°F. the film reached a thickness of about 2550 a.u. In the constant‐temperature tests the various types of enamels developed films in two hours that ranged from 60 to 2750 a.u. in thickness.
REACTIONS OF BeO AND SiO2; SYNTHESIS AND DECOMPOSITION OF PHENACITE*
Authors: Morgan R. A. , Hummel F. A. 
Published: October 2006

AbstractReactions of pure BeO and SiO2 were investigated at temperatures ranging from 1300° to 1700 °C. The synthesis and decomposition of phenacite were studied using willemite as an additive. A phase diagram is tentatively proposed on the basis of data obtained.
NOTES ON SILICATE ANALYSIS: II, DETERMINATION OF ZINC*
Authors: Osthaus B. B. 
Published: October 2006

AbstractIn silicate analysis, quinaldic acid is more selective than 8‐hydroxyquinoline or 8‐hydrosyquinaldine as a reagent for zinc in the presence of aluminum, titanium, iron, calcium, and magnesium. Zinc can be separated from these metals and the filtrate used for their determination without interference from an excess of quinaldic acid.
FURTHER FACTORS INVOLVED IN PRODUCTION OF THIN WALL TILE*
Authors: Lindquist C. Alan , Campbell R. M. 
Published: October 2006

AbstractWarpage tendencies of thinner wall tile were considered, and the practicability of producing wall tile 1/8 in. thick was investigated. The maximum permissible warpage was taken as 0.4%, which corresponds to the allowable warpage in the Simplified Practice Recommendation of the National Bureau of Standards. Wall tile 1/8 in. thick were produced successfully from both high‐talc and high‐pyrophyllite bodies. A unique method of measuring the warpage of wall tile is presented, which may have considerable application.
DISTRIBUTION OF HEAVY‐METAL IONS IN SILICATES CONTAINING SEVERAL ANIONS OF DIFFERENT SIZE*
Authors: Forland T. , Weyl W. A. 
Published: October 2006

AbstractA study of the color of minerals revealed that cobalt blue, the most common blue colorant in glasses, glazes, ceramic pigments, and synthetic minerals, seems to be almost completely absent in the mineral kingdom. This observation led to an investigation of the conditions under which the CoO4 groups form and to the composition of natural cobalt minerals. It was found that minerals containing Co2+ ions surrounded by oxygen must have formed generally at low temperature and that the cobalt was removed from the magma when the crystallization of silicates, aluminosilicates, and aluminates began. To explain this phenomenon, the distribution of heavy‐metal ions in silicate melts containing anions of different size was examined by means of model experiments.It could be demonstrated that these anions are statistically distributed around the heavy‐metal ions as long as the thermal energy is high and the interionic distances are large. With decreasing temperatures the statistical distribution changes into one that is governed by two energy terms, one resulting from the Coulomb forces, the other from the mutual polarization of the ions.On the basis of Fajans' theory of the deformation of ions it was possible to explain the formation of sulfidic ores from the original magma and the striking of glasses of the CdS type.
STUDY OF EFFECT OF CATION CONCENTRATION AND SIZE ON HELIUM PERMEABILITY OF ALKALI‐SILICA GLASSES*
Authors: Newkirk Terry F. , Tooley F. V. 
Published: October 2006

AbstractA study was made of the effect of systematic variations in the alkali‐cation concentration and size on the permeability of alkali‐silica glasses to helium at 300°C. Permeability determinations were made on fused silica, Pyrex‐brand chemical glass, Na2O‐SiO2 glasses containing 20, 25, and 30 mol % Na2O, a K2O‐SiO2 glass containing 30 mol % K2O, and a Li2O‐Na2O‐SiO2 glass containing 5 mol % Li2O and 25 mol % Na2O.Additions of Na2O to SiO2 glass produced a rapid decrease in the permeability of the glass. The permeability was found to decrease exponentially over the range 0 to 30 mol % Na2O. The substitution, atom for atom, of potassium for sodium increased the permeability of the glass, whereas lithium in combination with sodium decreased the permeability as compared with the soda glass. This was attributed primarily to the difference in the polarizing power of these cations that affected the ionic radius of the surrounding oxygens and resulted in a change in the packing density of the ions in the glass.A comparative packing index was calculated for the glasses based on the percentage of the absolute volume of glass contributed by the constituent elements. For the Na2O‐SiO2 glasses, increase in packing index (indicating a more closely packed structure) was accompanied by a decrease in permeability. It is suggested that (1) the comparative packing index is a potentially valuable index of permeability only for glasses containing the same atoms, (2) new atoms introduce a new polarizing factor in the glass, and (3) the packing index ceases to be comparative for the two glasses.
FUNDAMENTAL STUDY OF CRYSTALLINE AND GLASSY PHASES IN WHITEWARE BODIES*
Authors: Tuttle Milton A. , Cook Ralph L. 
Published: October 2006

AbstractA rapid and sensitive method for the quantitative determination of the crystalline constituents in kaolin‐flint‐feldspar blends has been developed with the Geiger‐counter X‐ray spectrometer. Two variations of this method were the use of (1) a powdered sample with a reference‐material addition and (2) a polished normal body surface. The powdered‐sample technique with a reference‐material addition showed the greater accuracy and consistency of results. The polished‐surface technique was slightly less accurate, but the preparation and nature of the test specimen make it very adaptable to control methods. With this technique the complete preparation and testing of the fired surface can be carried out in approximately 10 minutes. Standardization curves for the X‐ray spectrometer technique were used to obtain quantitative information concerning the crystalline constituents in the following blends: (1) kaolin‐flint, (2) kaolin‐feldspar, (3) flint‐feldspar, and (4) kaolin‐flint‐feldspar, as well as with additions of 1.2 and 2.8% lime and magnesia, and direct substitution of nepheline syenite for feldspar. Pressed 1 1/2‐in. pellets of each body were subjected to 3‐ and 12‐hour soaking periods at 1200° and 1400°C. Quartz, mullite, cristobalite, and wollastonite were identified as the crystalline constituents in the kaolin, flint, and feldspar blends studied. Quantitative X‐ray information concerning the reduction of the free‐quartz content, formation of cristobalite and mullite, and the amount of the total crystalline content was used to determine the effects of variations in composition and heat‐treatment for the different blends.
TESTING OF CLAYS FOR LIGHTWEIGHT AGGREGATE*
Authors: Klinefelter T. A. , Hancock Robert T. , Hamlin Howard P. 
Published: October 2006

AbstractA method of testing and evaluating clays suitable for the production of lightweight aggregate is presented. The procedures to be used with both the laboratory furnace and the pilot‐plant rotary kiln are outlined, and the determinations and tests necessary for relative comparisons of the products are described.
EFFECTS OF SOME ELECTROLYTES ON COLOR VALUE OF ENAMELS MADE FROM A STANDARD TITANIA‐OPACIFIED FRIT*
Authors: Marbaker Edward E. , Saunders Hollis S. , Baumer Leon N. 
Published: October 2006

AbstractJust as the properties of titania enamels are influenced by the clay used as the suspending agent in slip preparation, so it was thought that the salts used as electrolytes might also have effects of a similar nature. Six salts, KCl, K2CO3, NaAlO2, NaNO2, MgCO3, and KNO3, more or less commonly used as electrolytes for setting up titania enamels, were employed singly and in combinations of two and three in the preparation of 25 slips made from a standard frit. The clay content was 4%, and the milling conditions were constant. Slips, therefore, that varied in electrolyte content only were sprayed on ground‐coated steel plates, which were then fired uniformly. The set of the slips was determined by means of the Irwin slump test and the Brookfield viscometer. The reflectance, color value, finish, and acid resistance of the enamels were found by standard methods. The results showed that electrolytes have much more effect on enamel properties than has commonly been supposed and that, in the preparation of enamels, not only the quality of the frit but the properties of the components of the mill addition, clay and electrolyte alike, merit careful consideration in order to achieve the best possible results.
Epididymal obstruction results in isolated sperm heads in post‐vasectomy rats
Authors: Khaira Herkanwal S. , Schuster Timothy G. , Zhang Wen‐Xiang , Dunn Rodney , Smith Gary D. , Ohl Dana A. 
Published: October 2006

SummaryThe aim of this study was to determine if, following vasectomy, epididymal obstruction resulted in changes in vasal stump fluid using a rat vasectomy model. One hundred and twenty‐two mature male rats underwent bilateral surgical vasectomy and subsequent unilateral epididymal obstruction. Animals were randomly assigned to one of the five cohorts, which determined the time to kill and vasal fluid assessment. Numbers of whole sperm and sperm heads were compared between the obstructed and non‐obstructed sides. Parametric analysis of microscopic vasal fluid findings was performed using a paired t‐test. Whole sperm and sperm heads were detected bilaterally among the initial five cohorts. On the obstructed epididymis side, percentage of whole sperm dropped from 36.9% to less than 1% and sperm heads increased from 63.2 to 99.7% at 12 weeks post‐obstruction (p < 0.05 at each time interval). On the unobstructed side, percentage of whole sperm rose from 66.3 to 89.5% and sperm heads dropped from 33.7 to 10.5% (p < 0.05 at each time interval). At 12 weeks, the difference between the obstructed and non‐obstructed sides for both percentage and quantity of whole sperm and heads was significant with a p value of <0.001. In this rat model, following vasectomy and subsequent epididymal obstruction, testicular vasal stump fluid will contain progressively diminishing numbers of whole sperm and increases in the percentage and absolute numbers of sperm heads.
Peripheral INSL3 concentrations decline with age in a large population of Australian men
Authors: Anand‐Ivell Ravinder , Wohlgemuth Jessica , Haren Matthew T. , Hope Perdita J. , Hatzinikolas George , Wittert Gary , Ivell Richard 
Published: October 2006

SummaryThe novel peptide hormone insulin‐like peptide 3 (INSL3) is a major secretory product of the Leydig cells of the testis, and in adult men is secreted into the blood, giving rise to circulating concentrations ranging from 0.5 to 2.5 ng/mL. We studied a large randomly recruited cohort of 1183 men from South Australia, comparing serum INSL3 concentrations with age, and a variety of endocrine, cognitive and morphological parameters. While INSL3 concentration declines significantly (p < 0.001) and continuously with age from 1.29 ± 0.47 ng/mL in young men (age 35–44 years) to 0.79 ± 0.39 ng/mL in the age group 75–80 years, there is no correlation with testosterone or components of the hypothalamo‐pituitary‐gonadal (HPG) axis, independent of age, nor with any other parameter measured, including thyroid or prostate status and obesity. For men exhibiting normal follicle stimulating hormone (FSH) and high luteinizing hormone (LH) levels, there was a significant inverse correlation with plasma oestradiol. Unilaterally orchidectomized men had INSL3 values intermediate between intact men and anorchid subjects, and showed inverse correlations (p < 0.001) between INSL3 and FSH or LH concentrations, which were independent of age. Taken together, the data show that INSL3 is an independent measure of Leydig cell function (quality and number), which appears to be independent of acute control via the HPG axis. Its decline with age reflects a decline in the properties of the Leydig cell population only, and emphasizes a gonadal component in the age‐related decrease in androgen production.
Reframing birth: a consequence of cesarean section
Authors: Fenwick Jennifer , Gamble Jenny , Hauck Yvonne 
Published: October 2006

Aim.  This paper is a report of a study to describe the childbirth expectations, influences and knowledge of a group of Western Australian women who experienced a cesarean section (CS) and would prefer a CS in a subsequent pregnancy.Background.  Evidence suggests that a previous CS is not an indication for an elective CS in a subsequent pregnancy, but western world data indicate high probability of repeat CS.Methods.  Community advertisements invited women who had experienced a CS to participate in a telephone interview. The thematic analysis presented in this paper is derived from data collected during 2003/2004 from 49 participants who had initially expected to birth vaginal but had a CS and who had planned a CS in a subsequent pregnancy or stated that they would choose this option in a future pregnancy.Findings.  Before the first CS most women expected and wanted to give birth normally. After having a CS, however, many reframed vaginal birth as uncertain, unsafe and unachievable. For this group of women, the medical discourse that promoted CS as the safest option was a major influence on their decisions. As a result, they reconstructed CS as an acceptable alternative that was safer for them and their babies, allowed them to be better prepared, and was convenient.Conclusion.  In the present climate, enabling women to keep birth ‘fear’ in perspective may be an important strategy if we are to improve the uptake of vaginal birth after CS and the quality of care offered to women during the normal, but major, life event of childbirth.
Dimerization of plasmid DNA accelerates selection for antibiotic resistance
Authors: Mazin Alexander V. , Timchenko Tatiana V. , Saparbaev Murat K. , Mazina Olga M. 
Published: October 2006

SummaryDimerization of multicopy plasmids is widely assumed to be disadvantageous both for plasmid maintenance and for the host cell. It is known that dimerization causes plasmid instability; dimer‐containing cells grow slower than their monomer‐containing counterparts. However, as we demonstrate here, under conditions of selective stress, dimers provide an advantage for bacteria. Dimers facilitate segregation of mutants from numerous copies of the parental plasmid. Accelerated segregation greatly increases the rate of accumulation of plasmids carrying mutations that are adaptive for bacteria. In contrast, resolution of dimers by site‐specific recombination decreases, 103‐105‐fold, the efficiency of selection of spontaneous reversions in the tet gene of pBR327.
The hmu locus of Yersinia pestis is essential for utilization of free haemin and haem‐protein complexes as iron sources
Authors: Hornung Jan M. , Jones Heather A. , Perry Robert D. 
Published: October 2006

Summary Yersinia pestis strains utilize haem and several haem‐protein complexes as sole sources of iron. In this study, the haemin uptake locus (hmu) of Y. pestis KIM6+ was selected from a genomic library by trans‐duction into an Escherichia coli siderophore synthesis (entC) mutant. Recombinant plasmids containing a common 16 kb BamHI insert were isolated that allowed E. coli entC to use haemin as an iron source. An 8.6 kb region of this insert was found to be essential for haemin utilization and encoded at least five proteins with molecular masses of 79/77, 44, 37, 35, and 30/27.5 kDa. A 10.9 kb Clal fragment containing the hmu locus showed varying degrees of homology to genomic DNA from Yersinia pseudotuberculosis, Yersinia enter‐ocolitica, and other genera of Enterobacteriaceae. An E. coli hemA aroB strain harbouring cloned hmu genes used haemin as both an iron and porphyrin source but only on iron‐poor medium, suggesting that haemin uptake is tightly iron regulated. Additionally, haemoglobin and myoglobin were used as iron sources by an E. coli entC (pHMU2.2) strain. Deletion of the hmu locus from Y. pestis KIM6+ chromosome generated a mutant that grew poorly on iron‐depleted medium containing free haemin as well as mammalian haem‐protein complexes including haemoglobin, haemoglobin‐haptoglobin, myoglobin, haem‐haemopexin, and haem‐albumin unless it was complemented with cloned hmu genes.