Journal of the Ceramic Association, Japan最新文献

{"title":"Studies on the Hydration of 3CaO⋅Al2O3 by Calorimetry","authors":"Hirobumi Tanaka, K. Murakami, Izumi Manna, T. Karaki","doi":"10.2109/JCERSJ1950.70.803_302","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.70.803_302","url":null,"abstract":"","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1962-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81700528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the Temperature of Firing the Grog and the Green Body on the Physical Properties of the Pot for Melting Optical Glasses : Studies on the Pot used for Melting Optical Glasses, V","authors":"M. Ono","doi":"10.2109/jcersj1950.69.791_383","DOIUrl":"https://doi.org/10.2109/jcersj1950.69.791_383","url":null,"abstract":"The author's papers (J. Ceram. Assn. Japan, 63 [715] 566 (1955); J. Ceram. Assn. Japan, 64 [723] 110 (1956); 65 [733] 45 (1957); 65 [737] 104 (1957)) concerned the effects of the body composition etc. on the physical properties of the pot for melting optical glass which, however, did not cover the problems of the effects of firing temperatures of grog and green body.In order to summarize and reexamine the data a series of investigations on the spalling and load deformation properties of the pot materials containing the grog fired at the temperatures 1280°-1525°C and matured at the temperatures ranging from 1290° to 1545°C, have been carried out.The important results are as follows:(a) As far as the present test is concerned the strength of clay-grog bodies showed an increase with increasing firing temperature, while the elevation of the firing temperature of grog did not necessary show the same effect.(b) The total linear shrinkage from greeen to fired specimen increased with increasing firing temperature, but the same result could not always be expected with the grog.(c) The increase of bulk density with the firing temperature was observed with the body, but the same trend did not hold with the grog.(d) The strength of the body decreased with raising quenching temperature.(e) The quenched specimen subjected to the firing at higher temperature proved to be stronger so long as the quenching temperature was low, but when it was raised the difference became neglible.(f) The resistance to spalling decreased with the raise of quenching temperature.(g) Irrespective of the firing temperature of grog the body fired at higher temperature showed positively the poorer spalling resistance when it was quenched from higher temperature, but for lower quenching temperature this relation did not hold so that it is highly probable that the specimen fired at some intermediate temperature would show the lowest spalling resistance.(h) In the specimen fired at a higher temperature cracks in the intermediate layer between the grog and the bonding clay were observed, while it was impossible to locate such cracks in the body fired at lower temperature.(i) By quenching, cracks came into existence in the intermediate layer, and also the grow up of the existing cracks was observed. This phenomenon was most remarkable with the bodies composed of the grogs fired at higher temperature, as long as the green was fired at comparatively lower temperature.(j) The adhesion between the grog and the bonding clay seems to play the most important roll to the resistance to spalling of fire-clay pots.(k) The firing temperature of the body was found to be the most influential, whereas the influence of the firing temperature of grog seemed to be not so remarkable as the former.(l) Comparing the specimens prepared by high temperature with those by low temperature firing a marked difference was seen in the initial stage of load test, the latter being deformed much slower than the former. And ","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1961-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77166416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"酸化ウラン-酸化トリウム系の焼結酸化ウラン-酸化トリウム系焼結体の研究 (第1報)","authors":"敏之 佐多, 雷作 清浦","doi":"10.2109/JCERSJ1950.69.784_118","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.69.784_118","url":null,"abstract":"It is known that stoichiometric compositions of the urania-thoria system form a series of continuous solid solutions having some better properties as a nuclear ceramic fuel than urania only in oxidation resistivity, refractoriness, and usefulness of thoria as breeding materials. The sintered bodies of thoria-rich portion in the system have been studied since 1956-7 in Argonne National Laboratory, and subjected to the reactor tests, and going to be applied to fuel materials of power reactor.The authors have already published the results on the oxidation resistance and the sintering of the urania-rich portion of this system. This paper is concerned with their sinterings in air and reductions to stoichiometric compositions.The starting materials were the products of firing in air the coprecipitated mixtures of ammonium diuranate and thorium hydroxide obtained from mixed nitrate solutions of uranium and thorium by adding ammonia solution. The variation of pH by adding ammonium hydroxide to the mixed nitrate solution is shown in Fig. 1, and the calcination processes of the coprecipitates in air were traced by means of the thermogravimetric balance, with the results as given in Fig. 2. The tapped densities and Blain values of the calcinated powders in air at 800°C for 2 hrs. were measured, and also subjected to X-ray diffraction test. The results shown in Fig. 3 indicate that the grain size of he powders of containing 10-30% ThO2 are very small because of the hindrance of the crystal growth in the mixed phase of U3O8 and solid solution. The content of U3O8 phase has decreased and that of solid solution of fluorite type has increased as thorias were added to urania. U3O8 phase has disappered in the compositions containing thoria more than 60 weight%, forming only the solid solutions.The powders calcinated in air at 800°C were pressed at 3tons/cm2 to pellets of about 10mm in diameter, and sintered in air and reduced by CO gas. The results are given in Fig. 4 which show that the compacts containing 10, 20, and 30 wt.% of thoria have perfectly sintered at 1400°C, and those with 50% of thoria at 1500°C. The reduction of sintered pellets to stoichiometric composition by CO gas could be made more perfectly at higher sintering temperature, but the specimens containing less than 10% of ThO2 have cracked, as given in Table 1.The calcinated powder containing ThO2 30% was too fine to be pressed, and therefore the raising of calcination temperature up to 1000°C was tried. The sintering of these specimens showed a good results with the powder calcinated at 1000°C (Table 2). On the contrary the powders containing ThO2 50% was difficult to sinter at 1400°C, but this was possible by using the powder calcinated at 600°C (Table 3).The sintering in air of the uranium-rich specimens showed some faults of the volatilization of uranium component accompanying a large dimengional change at the reducing step. Therefore, the sinterings in neutral atomosphere, followed by hydroge","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1961-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75377076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the Minute Quantity of Impurities on the Transformation of Dicalcium Silicates","authors":"Kazutaka Suzuki, M. Tsujita","doi":"10.2109/JCERSJ1950.69.788_241","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.69.788_241","url":null,"abstract":"β-C2S may be obtained by water quenching from the temperatures higher than the α_??_α′ transformation. In this case, however, the batch should contain the impurities which stabilize the modifications of higher temperatures, β or even α, α′, by the substitution within crystal lattices.This paper concerns with the X-ray investigation of the stabilizing action of various amount of different impurities. Moreover, the authors discussed the stabilizing action from the results of the measurement of the change of the transformation temperatures of α′, β and γ.Cr, V, P, and B showed the marked effect especially for stabilizing β, so that it was possible to obtain β even by very slow cooling. Furthermore, the increasing substitution of Cr, V, and P for Si produced α, while that of B stabilized α′ form.Al, Fe, used alone were not powerful. They stablized β by water quenching from high temperature, but they were not able to produce α and α′ crystal.Ti, Mn have practically no power, and even the water quenched samples were contaminated by γ modification.From the results of the investigations of the series of batches containing comparatively large amount of substituting elements the authors concluded that Cr substitutes for Si4+ as the pentavalent ion. This result was compared with the action of other pentavalent ions, V, P and also with E. F. Osborn's work which showed that author's conclusion is reliable. Cr stabilizes α, β forms by the same action with V and P.The ionic radii of the stabilizing elements produce an effect on the expansion and contraction of the b-axis of β-C2S. Al3+, Fe3+, whose ionic radii are fairly larger than Si4+ are able to stabilize only β-C2S. Cr5+, V5+, P5+, the ions of nearly the same size as Si4+, may easily-substitute Si4+ and stabilize the α crystal of hexagonal symmetry from the monoclinic β form.B3+, an ion smaller than Si4+, stabilize α′ with the change of axial angle. Taking into consideration of the fact that Ba2+, a larger ion than Ca2+, can also stabilize α′, the author came in the same conclusion as that of the theory of stabilization advanced by A. Dietzel. We have discussed also the change of the size of lattices of α, α′ and γ brought about by substitution.Transformation temperatures of the modifications were measured by thermal analysis with a result that the transformation temperatures of β→α′ and α′→β were lowered in proportion to the amount of substituting agents. It was observed that the stabilization at high temperature was influenced by the nature and amount of impurities.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1961-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89797865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaction and the Solid Reaction Products in the System Lime-Silica Gel-Water at Ordinary Temperature","authors":"T. Yoshii, G. Sudoh","doi":"10.2109/JCERSJ1950.68.771_75","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.68.771_75","url":null,"abstract":"Calcium silicate hydrates, which are one of the principal bonding materials in mortars and concretes, are formed by puzzolanic reactions or hydrations of calcium silicate anhydrates.This paper is a report of an investigation of the reactivity of silica gel in lime solution, and deals with electronographic morphology, X-ray and electron diffraction analyses of solid phases.The initial C/S mol. ratios ranged from 0.50 to 3.50, and the solution was kept at the constant temperature of 20°±1°C for 95 days giving occasional agitation by a magnetic stirrer.For comparing the solid reaction products with the hydrated solid phases of calcium silicates in clinker, ordinary portland cement and β-C2S were subjected to similar tests.The results obtained are summarized as follows:(1) More than 90 days seem to be necessary before the system lime-silica gel-water reaches to neary stable equilibrium. CaO combines rather rapidly in the first week with the velocity decreasing with time. The effect of C/S mol. ratios in starting mixtures on these of the reaction products came to the front on long term experiments, for example, about 60 days.(2) C/S mol. ratios of the solid reaction products were in the range from 0.45 to 1.24 which showed a rapid increase up to about 0.8, the point of inflection, turned then to a slow increase even if an appreciable amount of CaO remained in the liquid phase. The principal factors governing the reaction were the initial C/S mol. ratio and the time of reaction.(3) The solid phases thus obtained were exclusively the aggregates of semi-transparent, thin, flexible films or foils being quite likely as having a gell-like structure as it was proved by the observation under electron microscope. The crystals often curled up to rolls, and gave the lattice spacing calculated from the pattern of electron diffraction usually smaller than that estimated by X-ray analysis. It is likely that this kind of difference is due to the shrinkage of crystals produced by the electron bombardment and also by high vacuum in electron microscope. Difference of C/S mol. ratios of the initial mixture did not give any recognizable influence on the properties of the solid reaction products. It is very likely that the variation of the C/S mol. ratios of solid reaction products is caused by the adsorption of CaO but not by the formation of solid solution. The filmy crystals may be the earlier stage of the crystalization of mono-calcium silicate hydrate (low temperature modification).(4) X-ray analysis showed the systematic absence of h k l for h+k odd. The reflection of (220) was abnormally strong and its peak profile traced by Geiger-counter diffractometer was generally unsymmetrical, which probably shows the two dimensional mistaked structure.(5) X-ray analyses showed the presence of calcium silicate hydrates in portland cement pastes (W/C=50%) cured 3-7 days. The observation under electron microscope of the paste cured 35 days revealed the existence of the semi-tra","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1960-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85702804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Capillary Water Absorption of Portland Cement Mortar Added with Large Quantities of Blast Furnace Slag","authors":"Gentaro Tsuneyama, T. Ozawa","doi":"10.2109/JCERSJ1950.67.763_238","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.67.763_238","url":null,"abstract":"A series of experiments was carried out with an idea that better blast furnace cement may be produced by the combination of the portland cement of normal fineness with finer blast furnace slag. The granulated slag was ground to nearly 5000cm2/g of Blaine fineness to mix, in different ratios, with the portland cement of 3000cm2/g. Using the mixture and normal sand the specimens of 1:3 mortar of the size 40×92φmm were formed, and after water curing the water absorption under the pressure of about 3mm of H2O was measured with an apparatus of the author's own design. Similar experiments were carried out, using the slag of the fineness of about 3000, 4000 and 5000cm2/g in order to know the effect of grain size. The strength of the mortar specimens 40×40×160mm in size were also tested.The following results were obtained:(1) Blast furnace cement containing 60, 70 and 80% slag of the size of about 5000cm2/g showed the absorption as low as 3-15% of pure portland cement after the age of 2 or 3 weeks.(2) The effect of grain size on the absorption fell gradually with age.(3) The absorption decreased with the increasing fineness of slag.(4) In early ages the difference of absorption between two cements containing 3000 and 4000cm2/g slags was far larger than those between 4000 and 5000cm2/g slags.(5) The difference of absorption caused by the fineness of slag decreased with the increasing age of specimen.(6) Compared with portland cement blast furnace cement showed a smaller ratio of absorption/evaporation telling that it had a higher drying rate than pure portland cement notwithstanding the lower surface of the specimen was always in contact with water.(7) Furthermore, it was noticed that the blast furnace cement gave a larger amount of bleeding water and a smaller content of air when filled in mould.(8) The blast furnace cement of 5000cm2/g powder gave higher two weeks strength than portland cement.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1959-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83595713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"炭化珪素の酸化におよぼす混入不純物の影響:炭化珪素粉末の酸化に関する研究 (第3報)","authors":"Hiroshi Suzuki","doi":"10.2109/JCERSJ1950.67.762_189","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.67.762_189","url":null,"abstract":"As a part of the studies on the oxidation of silicon-carbide powders the oxidazability of Si and β-SiC, both found in the market products of silican carbide, as well as the influence of Fe2O3, Al2O3 and MgO on the oxidation of pure green silicon carbide were investigated. The results obtained are summarized as follows:(1) Although it was confirmed that metallic silicon was oxidized much easier than α-SiC, the small volume increase accompanied by the reaction would play no more roll than to reduce the SiC content as long as the silicon carbide is used as refractories.(2) β-SiC is fine powder showing a very slow oxidation compared favourably with α-SiC in this respect. Consequently, it showed no trend to become porous, since no volume increase occured even though it was exposed to oxidizing atmosphare for a long time. The contamination of β-SiC in raw material is not only harmless but rather favourable.(3) It was confirmed that Fe2O3 did not give any serious influence on the oxidation of SiC at a temperature lower than 1200°C, and that there was no appreciable volume increase even in contact with water vapour. At about 1400°C the reaction became violent, which however, did not continue long, showing that Fe2O3 is not so harmful an admixture as it is universally believed.(4) At all temperatures Al2O3 held back more or less the oxidation of SiC. It was observed that a violent oxidation occured at 1150°C under the coexistence of water vapour, accompanying large volume and porocity increase. It was thus confirmed that Al2O3 is an impurity to which we should use due precaution against its contamination.(5) MgO is an impurity accerelating the oxidation of SiC at the temperatures higher than 700°C, it is one of the most undesirable impurities.(6) The influence of oxides on the oxidation of SiC is governed:(a) by the stability discriminated by the free energy of the formation of oxides, (b) by the location of the melting points in the binary system [metal oxide]-SiO2, (c) by the reactivity of metal oxide with SiO2, (d) by the properties of the reaction products.Referring to the influence of the addition of Pb3O4, V2O5, and Li2CO3 on the oxidation of SiC such conditions as above were explained satisfactory.(7) The prolonged oxidation of SiC is governed mainly by the nature of the oxide film covering the crystal surface. The fact that even the pure green silicon carbide behaved like an ordinary black silicon carbide when mixed with Al2O3 or MgO may be attributed to the nature of accerelating the crystallization of amorphous silica to quartz and cristobaite.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1959-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83365992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabricating the Cermet of the System Alumina-Chromium by Hot Pressing","authors":"T. Sata, R. Kiyoura","doi":"10.2109/JCERSJ1950.67.760_116","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.67.760_116","url":null,"abstract":"Alumina-chromium cermet bodies containing 20 to 70 vol. % Cr were hot-pressed at 1400°-1470°C and 150kg/cm2 for 20-30 min., in argon atmosphere using graphite molds having a circular hole of 8mm in diameter, or a rectangular hole of 4×15mm.From the results of this study it was concluded that:(1) In hot pressing, increase in the chromium content decreased the press-temperature, for instance, 1400°-1430°C for 60 vol. % of chromium, being about 300°C lower than the hot-pressing temperature in hydrogen atomosphere (Table 1).(2) Measuring the hardness distribution along the center line of hot-pressed bodies whose hight to dia. ratio was 2:1 the method of pressing was studied, and the best result was obtained when the pressure was applied with a plunger moving downwards in a floating die. (Table 2 and Fig. 3).(3) The distribution of hardness in hot-pressed bodies of complex shape was studied with a result that there are some regions giving lower hardness values caused by the lack of the flowability of the mix, which suggests the necessity of three directional pressing (Photo. 2).(4) The transverse rupture strength of hot-pressed bodies of the size 4×4×15mm were 55-72kg/mm2 at room temperature.(5) The microstructure of hot-pressed bodies was characterized by the occurence of smaller corundum crystals of the order 1-3μ, and by the more rough boundaries between the alumina and chromium phase than those in the bodies sintered in hydrogen atmosphere. Continuous metallic phase was observed in the hot-pressed bodies containing more chromium than 60-70 vol. % (Photo. 3).(6) Fractures in the tension side of the specimens of bending rupture test passed through the crystals. of corundum, chromium as well as their phase boundary, and consequently, both chromium and corundum phases were appeared in the electron microphotographs (Photo. 4-5).","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1959-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90956862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Fixation Phenomenon of Adsorbed Cations on Halloysite Caused by Drying","authors":"S. Okuda, Keikichi Inoue","doi":"10.2109/JCERSJ1950.67.765_294","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.67.765_294","url":null,"abstract":"In part I of this series physico-chemical studies on the fixation phenomenon of the cations adsorbed on kaolinite caused by drying were carried out and a new theory of the fixation of adsorbed cations, being quite different from any current theories which have been introduced so far by soil scientists, was advanced by the authors.In the present paper the fixation phenomenon of adsorbed cations such as Li+, Na+, K+ and Ca++ on halloysite surface caused by drying was studied. it was confirmed that the mechanism of the fixation for kaolinite may also be applicable to halloysite.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1959-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86564679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyses of Density Phenomena of Glass by a Reaction Model:Density Change of Glass due to Heating (Part 3)","authors":"T. Kishii","doi":"10.2109/jcersj1950.66.749_117","DOIUrl":"https://doi.org/10.2109/jcersj1950.66.749_117","url":null,"abstract":"Density changes of glasses in and near their annealing ranges were studied by many investigators. Kanai and Satoh proposed a theory which analyzed change of density with time by introducing the concept of network temperature and the reaction model, but, hereafter, some particular phenomena were observed which could not be explained by their theory and further extension has been needed.In this paper, this extension is done and it is shown that the density phenomena studied by Daragan or Ritland, or particular ones observed by Suetoshi and Hara, Tsurumi, or by the author, can be analyzed rather quantitatively by introducing some energy levels which can be occupied by glass structures, transitions of states between them and changes of transition probabilities with temperature, and by making suitable assumptions for them.It is also speculated that secular changes of ice point or thermal after-effects of glass thermometers can be explained with similar concepts and mathematical treatments.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1958-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87973726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}