In order to clarify the thermal cracking conditions, experiments were carried out on model specimens simulating mass concrete. In Part 1, cracking conditions of mass concrete subjected to rapid ...temperature change and cracked in 1〜2 hours after heating, were investigated. In this case, the effect of time-dependent deformation due to flow of concrete was mostly eliminated. Disk-shaped specimens with various size were subjected to partial heating at the center of the disk. The specimens were heated so that the maximum tensile stress and strain would be produced along the perimeter of the specimens. Temperature distributions in the cross sections of the specimens after heating, and the moment of cracking were measured. The actual thermal stress was also estimated by comparing the splitting strength of specimens under heated and cold conditions. The age of concrete when tested, ranged from 6 hours to 160 days. In the analysis of test results, the concept of temperature distribution coefficient, F_0, was introduced. F_0 was derived from the elastic thermal stress theory. The results show that the apparent splitting strength of concrete under heating decreased in proportion to the F_0 value, and crack occurred when the F_0 value reached 9〜12℃, irrespective of mix proportion, age of concrete, size of specimen and others. By this test, it was clearly shown that cracking condition of concrete subjected to rapid temperature change could be evaluated by F_0 value as parameter.
Viscosity of Slag Melts Containing Fe2O3 Sumita, Shigeo; Mimori, Takashi; Morinaga, Ken-ji ...
Journal of the Japan Institute of Metals and Materials,
1980, Volume:
44, Issue:
1
Journal Article
Peer reviewed
Open access
Effects of Fe2O3 on the viscosity of silicate and ferrite slag melts have been studied in terms of the oxygen co-ordination number of Fe3+. Fe2O3 was amphoteric oxide like Al2O3 in these melts. Two ...parameters determining the behavior of Fe2O3 were proposed for these melts. One is the basicity of melts, and the other is the ratio of alkali (R2O)-, alkaliearth(RO)-oxide/Fe2O3 as seen for Al2O3. The portion of Fe3+ (4-co-ordinated oxygen) like Si4+ was increasing with increasing the basicity and/or the alkali-, alkaliearth-oxide/Fe2O3 ratio. In Na2O-Fe2O3 and BaO-Fe2O3 systems, the maximum was observed in viscosity-composition curves at the composition corresponding to Na2O or BaO/Fe2O3\fallingdotseq1. This could be explained by considering a change of the co-ordination number of Fe3+ with Fe2O3 content in the melts.
The viscosity in the (alkali oxides and alkaline earth oxides)-SiO2-TiO2 system and in the PbO-SiO2-TiO2 system was measured by a crucible-rotating method. In the melts (RO, R2O):SiO2=7:6, the ...viscosity decreased with the addition of TiO2. The results of this viscosity and the electrical conductivity obtained in the previous work suggest that 4 co-ordinated Ti ions having the titanate anions are isolated, and will not link the silicate anions like Al2O3 in the silicate melts. In the PbO-SiO2-TiO2 system, when the molar ratio of PbO/SiO2=1, the viscosity also decreased with increasing TiO2, but it increased when PbO/SiO2=7⁄3. It may be considered that the Pb2+ ions which have a role of network modifier in silicate decrease and result in a higher polymerization state of silicate anions, as 4 co-ordinated Ti ions increase in the melt having the composition PbO/SiO2=7⁄3. The existence of 4 or 6 co-ordinated Ti ions in silicate glasses was determined by measurement of far-infrared spectra in the range of 20000∼70000 m−1.
Candida albicans-induced histamine release from basophils was studied in 54 patients with bronchial asthma in comparison with the release caused by house dust and anti-IgE. The release of histamine ...induced by C. albicans and that induced by house dust were closely related to the serum levels of specific IgE antibodies as expressed by RAST scores. A correlation of C. albicans-induced histamine release with the release caused by anti-IgE was not generally observed. On the other hand, a close correlation was found between house dust- and anti-IgE-induced histamine release. It was suggested from these results that the differences between C. albicans- and house dust-induced histamine release might be due to the different antigenicity of the two allergens.
In order to clarify the relationship between human papillomavirus (HPV) and a variety of surface epithelial lesions, the presence of papillomavirus genus-specific common structural antigen ...(pgs-antigen) was immunohistochemically investigated in 256 cases of various tumors and tumorous lesions. The pgs-antigen was demonstrated in cases of verruca vulgaris (11/23 cases), condyloma acuminatum (13/26), adult laryngeal papilloma (3/12) and bowenoid papulosis (2/2). No pgs-antigen was observed in ordinary Bowen's disease and other hyperkeratotic skin lesions, such as keratoacanthoma and seborrheic keratosis. In uterine cervical lesions, about 15% of cervical dysplasia, most of which later developed into carcinoma in situ, contained pgs-antigen-positive koilocytotic cells. These results suggest that HPV infection is frequently present in human hyperplastic and atypical surface epithelial lesions of Japanese patients and might indicate possible association with neoplastic transformation, especially in the cervix and skin.
A case of a solid parotid tumour in a 16-year-old boy is presented. Histologically, the tumour demonstrated some peculiar findings. An acinar pattern was predominant although every component seen in ...the normal salivary gland was present, namely, serous and mucous gland acini, ducts, myoepithelial cells, adipose and lymphoid tissue. Large eosinophilic granules were abundant in the large acinar cell cytoplasm. Immunohistochemically, the tumour demonstrated the proteins which are present in the normal parotid gland, for example, amylase, lactoferrin and lysozyme. Electron microscopic features were quite similar to those of normal parotid tissue except for accumulation of a large number of cytoplasmic granules in the acinar cells. There has been no previous report of a tumour with the same features as seen in this case. Our pathological diagnosis is hamartoma, although the possibility of hyperplasia or neoplasia can not be excluded.
Cancer incidences for major sites were compared among Koreans in Osaka, Japan, Koreans in Korea and Japanese in Osaka by calculating standardized proportional incidence ratios (SPIR's), in addition ...to updating the findings on cancer mortality experiences of Koreans and Japanese in Osaka reported before. Compared with Japanese, Koreans in Osaka had significantly higher mortality rates from cancers of the esophagus, liver and lung in males, and liver in females. Mortality rates among Koreans in Osaka were significantly lower for stomach cancer in both sexes and for breast cancer in females. Compared with Korean counterparts in the homeland, Koreans in Osaka had a reduced risk for cancers of the stomach in males and the uterus in females. On the other hand, an elevated risk was observed for cancers of the esophagus, colon, liver and lung among Korean males in Osaka and for cancers of the colon and liver among Korean females in Osaka. The risk for cancer of the breast in females was similar among Koreans in the host and home countries. These different cancer patterns among Koreans in the host and home countries and Japanese are discussed in relation to their life styles, such as smoking, drinking and dietary habits, which have been investigated by means of questionnaire surveys.
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