bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF MOISTURE UPON ELECTRICAL RESISTANCE OF EMBEDDING CEMENTS*
Authors: Melton R. L. , Brownell K. W. , Easter G. J. 
Published: October 2006

ABSTRACTFor insulating electrical resistors from the casing of household appliances, etc., ceramic cements when properly applied are superior to other materials. If not sufficiently vitrified after application, however, they absorb moisture, thus tending to lower their resistance sufficiently to permit users of the appliances to experience electrical shocks. The necessary firing temperature varies widely with different cements. Some are satisfactory when cured by the heat of the embedded resistor alone while others are not. The hygroscopic properties are shown to be markedly increased by the presence in the cement of bentonite, borax, mica dust, or glass cullet. The borax also reduces the ultimate resistance objectionably at higher temperatures.The apparatus used for testing is described in detail.
THE ANALYSIS OF FELDSPAR*
Authors: Knowles H. B. , Redmond J. c. 
Published: October 2006

ASSTRACTThe methods commonly used for the chemical analysis of feldspar require an excessive amount of time, particularly if the analysis is to be used only for grading the material and where great accuracy is not essential. More rapid methods are described for determining alumina, calcium oxide, and the alkalis. In these, alumina is determined by precipitating with 8‐hydroxyquinoline in acid solution and then titrating an acid solution of the precipitate. Calcium oxide is determined by precipitating with oxalic acid without prior removal of aluminum and then titrating with standardized potassium permanganate. The alkalis are weighed as chlorides and potassium is determined by difference after sodium has been weighed as the triple acetate. Optional methods for attacking feldspar by acid instead of by fusion are described.
THE WATER‐SMOKING PERIOD AND ITS CONTROL*
Authors: Carruthers J. L. 
Published: October 2006

ABSTRACTThe importance of the water‐smoking period, the work done, and the difficulties often encountered during this period in firing heavy masses are reviewed. The reasons for and the methods of preventing these difficulties are discussed. Maintenance of the dew‐point of the kiln gases several degrees below the temperature of the ware that the gases contact until all the ware is heated to 212°F is suggested as a method for obtaining desired kiln conditions and efficient firing. The dew‐point is controlled by rate of combustion and amount of excess air. A control system consisting of an aspiration psychrometer and a pyrometer and the method of using these instruments are described.
THE CONVERSION OF QUARTZ INTO CRISTOBALITE BELOW 1000°C, AND SOME PROPERTIES OF THE CRISTOBALITE FORMED*
Authors: Cole Sandford s. 
Published: October 2006

ABSTRACTAn investigation of the conversion of quartz into the higher temperature forms of silica was made in order to establish whether cristobalite or tridymite is first formed in the temperature range 850 to 1050deg;C. The results of over 800 determinations established the fact that sodium silicate promotes the conversion and is materially superior to other fluxes reported in the literature.Cristobalite forms before tridymite in the conversion of quartz at 890 to 900°C. The rate of conversion is dependent upon time and temperature. The cristobalite in the temperature range studied was metastable and slowly converted to tridymite. The inversion of the low to the high form of cristobalite occurred at 250 to 260°C on heating. The refractive index was found to be in agreement with that for cristobalite formed at higher temperatures. The conversion is believed to be one of a solid‐liquid type, and a theory to explain the formation of cristobalite before tridymite is offered, based on the crystal lattice structure changes required to develop the two high‐temperature forms of silica from quartz.
PROPERTIES OF SOME OHIO RED‐FIRING CLAYS*
Authors: MacGee A. E. , White W. C. O. , Klinefelter T. A. 
Published: October 2006

ABSTRACTProperties of twenty‐six Ohio clays representative of those used in manufacturing heavy ware, such as brick and hollow‐ware, were studied from the raw clay to the finished laboratory product. Chemical and petrographic analyses were made. In the raw and plastic states data were obtained on the tempering water, the amount of load necessary to extrude the clay through a die, the base‐exchange capacity, and the particle‐size distribution as evidenced by sieve analysis and the water‐absorption method. In the dry state the minimum drying time, the shrinkage, porosity, apparent specific gravity, dry transverse strength, impact strength, and modulus of elasticity were determined. In the process of heating the clays to 1000°C, observations were made as to the kind and rate of evolution of the gases given off, the endothermic and exothermic reactions, and the expansion characteristics. The softening points of the clays were determined and, after heating to different temperatures, data on shrinkage, absorption, and transverse strength were taken.
PROPERTIES OF SOME AMERICAN KAOLINS AND A COMPARISON WITH ENGLISH CHINA CLAYS*
Authors: Klinefelter T. A. , Meyer W. W. 
Published: October 2006

ABSTRACTNine American kaolins were studied. Chemical analyses were made and equivalent mineral compositions were calculated with the aid of petrographic examinations. Pyrometric cone equivalents, deflocculating characteristics, soluble‐salt contents, percentages of material composed of particles less than 0.6 micron in diameter, and base‐exchange capacities at pH7 were determined. Transverse strengths of dried and variously heat‐treated bars, made from mixtures of the clays with equal parts of potters' flint and shrinkages and apparent porosities of dried and progressively heat‐treated allclay specimens, were determined. Specimens of the dried and heated clays were examined for relative color, and linear thermal expansions of specimens heated to various temperatures were determined. The nine clays were divided into three groups and their properties compared with those of fifteen English china clays previously studied. Simulation of essential properties of the English china clays was accomplished in supplementary experiments by adding fluxes to American kaolins or kaolin blends.
FORSTERITE AND OTHER MAGNESIUM SILICATES AS REFRACTORIES*
Authors: Birch Raymond E. , Harvey Fred A. 
Published: October 2006

ABSTRACTIn a survey of magnesium silicates for use as refractories, experimental studies with talc, serpentine, and olivine, and also with mixtures of these minerals and magnesia (MgO) are reported. Since forsterite (2MgO°SiO2) is the only magnesium silicate which has a stable existence above 1562°C, the development of a commercial magnesium silicate refractory required that the ultimate product should be mainly forsterite. Such a refractory was developed by enriching a low iron magnesian olivine with MgO. The magnesia served to convert certain accessory minerals found in the olivine rocks, including the hydrated minerals (talc and serpentine), to forsterite. Talc and serpentine are so universally present in olivine that, in the absence of the magnesia treatment, they provide a low melting bond which would cause the refractory to fail at relatively low temperatures under load and to exhibit other unsatisfactory properties. On the other hand, the forsterite refractory withstood an exceptionally high temperature before failure under load.The general characteristics of the refractory are discussed. The data include refractoriness, strength hot and cold, volume stability when reheated, spalling, thermal expansion, chemical behavior, resistance to various slags, thermal conductivity, etc.
THE EFFECT OF REPEATED FIRING UPON THE SPECIFIC GRAVITY AND MICROSTRUCTURE OF SOME ALUMINUM‐SILICATE MINERALS*
Authors: Riddle Frank Harwood , Peck Albert B. 
Published: October 2006

ABSTRACTRepeated firing of several aluminum‐silicate minerals to the same temperatures show that the specific gravities of the fired products do not drop at the same rate. Petrographic‐microscopic examinations show that this is due to different rates of dissociation in the minerals. While these rates of reaction or dissociation can not be measured accurately, some idea of the relative rates can be obtained by comparison of the sizes of completely dissociated grains of the minerals or of the widths of the borders of the dissociation products formed around the grains. Furthermore, the effect of repeated firing upon the increase in size of mullite crystals formed when the minerals dissociate gives evidence concerning the rate of growth or probable refractoriness of the minerals. These are described in some detail and close correlation between them and the specific gravity changes are pointed out.
A STUDY OF SOME CERAMIC BODIES CONTAINING TALC*
Authors: Fallon Frank P. 
Published: October 2006

ABSTRACTFluxing agents used in most steatite bodies contain alkalis which lower the electrical resistivity of these insulators. Attempts were made to obtain a vitreous steatite composition by additions of oxides containing no alkalis. The effect of grain size, liquids, and varying pressures was determined to obtain the best mixture which would produce the lowest absorption when fired to cone 14, and to this mixture the various oxides were added. The absorption and shrinkages were obtained after firing to cones 13 and 14.
EFFECT OF FURNACE ATMOSPHERE AND PARTIAL VACUUM UPON THE VITRIFICATION OF A HIGH MULLITE PORCELAIN*
Authors: Hossenlopp A. M. , Russell R. 
Published: October 2006

ABSTRACTA high mullite porcelain body was fired in various atmospheres and in vacuum. O2, CO2, and N2 atmospheres and vacuum were used separately for the firing, preceded by an oxidizing atmosphere up to 1000°C. The effect upon density and vitrification temperature and range was determined. An oxidizing atmosphere in all stages of firing is advantageous in obtaining high density. Firing in vacuum lowers the vitrification temperature 100°C and increases the vitrification range 20°C.
INVESTIGATION OF GLASSHOUSE SUPERSTRUCTURE MATERIALS*
Authors: Fabianic W. L. 
Published: October 2006

ABSTRACTA practical investigation was conducted on the selection of those refractories most suitable for use in glass‐furnace port jambs, port sills, port floors, baffles, port‐nozzle side walls, port side walls proper, and top checker courses. These refractories are exposed to the destroying action of a viscous high‐temperature basic slag and batch dust of a given composition. Over one hundred various brands of brick were tested, ranging in composition from a first‐grade fire brick to super‐refractories of the 80% alumina class. The mechanical, chemical, physical, and mineralogical properties of these brick were studied. The results of the test determinations were checked by making actual service installations in operating furnaces. The performance of the refractories in these installations after ten months of service verified the test results to a remarkable degree. The mineralogical relationship of the minerals in the refractory as received was found to be of more importance than chemical or physical properties. A tentative method of determining the suitability of a brick for actual service by combining petrographic inspection with physical properties is suggested.
MORTARS SUITABLE FROM THE STANDPOINT OF WATER‐TIGHTNESS IN UNIT MASONRY*
Authors: Palmer L. A. 
Published: October 2006

ABSTRACTThis paper deals with results obtained in the leaky masonry study at the National Bureau of Standards. Possible improvements in test procedures in future investigations are indicated. The relative importance is shown of mortar properties on the one hand and brick properties on the other as they are concerned either with causing or preventing leaky masonry.
THE INFLUENCE OF SODIUM ALUMINATE IN A FIRECLAY SEWER‐PIPE BODY*
Authors: Carter W. K. , Duncombe Geo. H. , Hillyer E. E. , King R. M. 
Published: October 2006

ABSTRACTA laboratory study of the effect of sodium aluminate on the fired properties of a fire clay used in sewer pipe is discussed, especially with respect to the original kiln strength and strength permanency. The results of commercial applications of sodium‐aluminate additions in sewer‐pipe plants are given.
TALC IN WHITEWARE BODIES OF THE WALL‐TILE TYPE*
Authors: Geller R. F. , Creamer A. S. 
Published: October 2006

ABSTRACTEffects of MgO and of CaO, introduced as a lime‐free talc and as a lime‐bearing “tremolite” talc, in whiteware heated at four temperatures were investigated. The results indicate that (1) in earthenware bodies, 40% or less of talc may be expected to increase porosity slightly and materially decrease shrinkage, (2) thermal expansion may be greatly affected by small variations in the amount of talc used, the temperature of heating, and the percentage of CaO, and (3) talc has a beneficial effect on resistance to moisture crazing.
X‐RAY DIFFRACTION STUDY OF THE STRUCTURE OF SODA‐SILICA GLASS*
Authors: Warren B. E. , Loring A. D. 
Published: October 2006

ABSTRACTX‐ray diffraction patterns of soda‐silica glass have been made for seven different compositions varying from O to 46% Na2O. For small soda content, the patterns show a single strong peak at sinθ/λ= 0.12; with increasing soda content this peak diminishes in intensity, while at the same time a new peak at sinθ/λ= 0.18 gradually becomes the more pronounced. There is no abrupt change in the patterns. A random network picture of the glass is developed, and upon this basis X‐ray intensity curves can be calculated in good agreement with the experimental curves. Each silicon is tetra‐hedrally surrounded by four oxygens. Part of the oxygens are shared between two silicons; the others are bonded to only one silicon. The double‐bonded oxygens build up a continuous silicon‐oxygen framework. The sodium atoms are located at random in the various holes in this framework. There is no evidence for the existence of compounds in the range of composition studied.
TEST DATA ON STIFF‐MUD REFRACTORIES MADE FROM GEORGIA SEDIMENTARY KAOLINS UTILIZING VOID CONTROL*
Authors: Vaughan W. Harry 
Published: October 2006

ABSTRACTA discussion is given of the pyrophysical characteristics of different types of Georgia sedimentary kaolins suitable for refractories. Working and drying character, shrinkage, absorption, fired crushing strength, spalling resistance, pyrometric cone equivalent, and load‐bearing properties at high temperatures are given for some bodies made of semihard and hard sedimentary kaolins.
THE NATURE OF THE GLASS PHASE IN HEATED CLAY MATERIALS* I. COMMON CLAYS†
Authors: Shelton G. R. 
Published: October 2006

ABSTRACTThe progress of fusion in an alluvial clay, a glacial clay, and a shale, when heated at various temperatures, was determined with the aid of the petrographic microscope. Thin sections and powdered samples obtained from the heated clay specimens were used in these tests. The relationships between the amounts and kinds of glasses in the specimens and the properties of the glasses were determined. Shrinkage and porosity of the specimens were found to depend not only on the temperature at which glass formation started but also on that at which the glass became sufficiently fluid to allow contraction of the specimen to take place. The colors of the heated clay specimens were governed largely by the crystallization of the glass bonds. Solution of the crystals formed by devitrification also profoundly affected the colors of the specimens. The increase in intensity of the red color of the specimens of alluvial clay and shale was directly related to the increase in the number of red crystals produced in the glass phases. The loss of red color by these specimens heated at very high temperatures in an oxidizing atmosphere and also at lower temperatures in a reducing atmosphere was caused by solution of the red crystals. The glassy bond in the specimens of glacial clay differed in composition from that in the alluvial clay and shale, which prevented the development of a red color of the specimens. A black glass, formed on solution of the red crystals, produced a dark gray color in the overheated specimens and in those heated in a reducing atmosphere. The growth of fine‐grained green crystals in the glacial clay specimens was a factor in neutralizing the small amount of red color originally in these test pieces.
A STUDY OF FURNACE ATMOSPHERES AND TEMPERATURE GRADIENTS AND THEIR EFFECT ON PORCELAIN ENAMELING*
Authors: Ebright H. E. , Mcintyre G. H. , Irwin J. T. 
Published: October 2006

ABSTRACTThe factors affecting variations in furnace atmospheres and temperature gradients are discussed. Analytical methods and technique used in determining temperature gradients are given. Typical furnace atmosphere compositions are reported together with their effects on enamel‐ware quality and production. Several specific cases of shop troubles which are traced back to the firing furnace and the corrections applied are discussed in detail.
THE FINENESS DISTRIBUTION OF VITREOUS ENAMEL AS AFFECTED BY VARIATIONS IN GRINDING*
Authors: Poste E. P. 
Published: October 2006

ABSTRACTThe results of an experimental study of the effects of variations in some of the conditions of grinding vitreous enamels on the distribution of particle size are given. These are followed by observations on the distribution of particle size in commercial batches of various enamels.
INVESTIGATION OF SOME PHYSICAL FACTORS AFFECTING THE DRAINING QUALITIES OF GROUND‐COAT ENAMELS*
Authors: Noble W. N. , Lindsey G. S. 
Published: October 2006

ABSTRACTThe temperature of milling of sheet‐iron ground‐coat slip, rapid cooling versus slow cooling, and the temperature of the slip for draining are shown to affect draining qualities. The amount of water used for milling also influences the draining properties. No great differences, except better retention of set under the former condition, occur from milling ground‐coat frit separately and blending after milling compared to blending before milling.
KINETICS OF SOLID‐PHASE REACTIONS OF CERTAIN CARBONATES WITH MULLITE, SILICA, AND ALUMINA*
Authors: Pole Gordon R. , Taylor Nelson W. 
Published: October 2006

ABSTRACTQuantitative measurements of the rates at several temperatures of reactions between carefully sized solids have been made by determining the amount of CO2 evolved as a function of the time. While the absolute rate is a function of grain size and other factors, the temperature coefficient gives a constant characteristic of the chemical system involved. The reaction product is found to lessen the speed of reaction in accordance with the relation, dyjdt=k/y, where y is the thickness of the layer of reaction product. Under comparable conditions, sodium carbonate attacks mullite most easily, with less attack on quartz, and least on corundum. The activity of calcium carbonate on mullite, quartz, and corundum is considerably less marked. Applications to glass melting and to corrosion of refractories by alkali or alkali‐earth dusts are discussed. A table of values of the function, , for positive integral value of x form 1 to 100 is included.
THE DETERMINATION OF ALKALIS IN SILICATES WITH SPECIAL REFERENCE TO HIGH‐ALUMINA REFRACTORIES*
Authors: Read Edgar B. 
Published: October 2006

ABSTRACTThis investigation pertains to the detailed study of two methods used to determine alkalis in silicates. The work was prompted through the difficulty of obtaining complete decomposition of high‐alumina refractory materials by the usual procedure.It was found that high‐alumina materials may be decomposed by the J. Lawrence Smith procedure with a single fusion, provided this is conducted at approximately 1200°C.The second procedure has to do with the decomposition of the sample with a mixture of nitric, sulfuric, and hydrofluoric acids. In this method, magnesia is eliminated by precipitation with 8‐hydroxyquinoline and the alkalis are weighed as sulfates. Experimental data are given pertaining to these procedures when used for the analysis of several types of materials.
Viscosity and Electrical Resistivity and their Bearing on the Nature of Glass*
Authors: Taylor Nelson W. 
Published: October 2006

AbstractThe mechanisms of viscous flow and of electrolytic conduction in liquids have been examined to show the significance of the activation energy which is evaluated from the temperature coefficients of viscosity and electrical resistivity. It is shown that the high numerical values characteristic of silicate glasses arise from the ionic character of the liquid, the small coordination number (4) for silicon, and the high electric charge on the ions (Si, 4; 0,2; etc.). Below the softening range, a glass is not necessarily stabilized (i.e., in equilibrium with respect to molecular association or dissociation processes) and its properties depend on its history, mechanical, thermal, etc. In stabilized glasses, the activation energies for viscosity and electric resistivity rise continually with falling temperatures, showing no maximum, in contrast to the views of Preston and Seddon.The oxygen, to silicon ratio has a dominating rôle in the structure of silicate crystals, as shown by W. L. Bragg. Similar concepts are applied to glass, and it is shown that the Preston‐Seddon proposal of definite compounds in soda‐silica glasses may be replaced by an alternate explanation.The quantity, β, in the equation, η=arβ, which relates viscosity to resistivity, has a value of 4 to 6 for certain soda‐containing glasses. The suggestion is made that viscous shear requires the breaking of four to six times as many sodium‐oxygen bonds as does electrical conduction.Finally, an internal energy‐temperature curve, based on specific‐heat data for fused silica, has been constructed. The curve shows a. steady rise with increasing temperature. It is typical of several glasses.
DIRECT DETERMINATION OF SODIUM OXIDE IN FELDSPAR*
Authors: Koenig E. W. 
Published: October 2006

AbstractA method for the direct determination of sodium oxide in feldspars is described. Data derived from an investigation conducted to determine the optimum conditions for the accurate estimation of this alkali metal by the prescribed procedure are tabulated and the results are discussed. The application of the method to the analysis of other related silicates is mentioned briefly.
USE OF BROMATE IN VOLUMETRIC ANALYSIS: VII, POTENTIOMETRIC TITRATION OF HYDROXyQUINOLINE *
Authors: Smith G. Frederick , May R. L. 
Published: October 2006

AbstractThe potentiometric titration of 8‐hydrOxyquinoline and the metallic inner complexes, i.e., magnesium oxyquinolate, is described, using direct titration with a standard bromate solution of the hydrochloric acid solution of the hydroxyquinoline or its derivatives with particular reference to magnesium oxyquinolate. Potentiometric procedures for direct determination have been developed using the electrode system, platinum‐nickel. This procedure involves the use of the monometallic, platinum‐platinum electrode pair and the electron beam sectrometer as the recording instrument, which has a distinct advantage of speed and equal accuracy over previous electrometric titrations. A series of experimental analyses has been carried out both on the hydroxyquinoline and its magnesium salt. The procedure is well adapted to routine plant control analyses, and a separation of calcium prior to the determination of magnesium is not required.
CRITICAL STUDY OF THE DIFFERENTIAL THERMAL METHOD FOR THE IDENTIFICATION OF THE CLAY MINERALS*
Authors: Norton F. H. 
Published: October 2006

AbstractAn apparatus is described for studying clay minerals by the differential thermal method, which has some advantages over previous types of apparatus. Thermal curves are given for many of the pure clay minerals for use as standards of identification. The use of this method quantitatively for the determination of the relative amounts of clay minerals in a natural clay is discussed, and examples are given for a number of high alumina clays.