- 著者
- Zhenzhen Wang Abudushalamu Aili Masayo Minami Ippei Maruyama
- 出版者
- Japan Concrete Institute
- 雑誌
- Journal of Advanced Concrete Technology (ISSN:13473913)
- 巻号頁・発行日
- vol.21, no.11, pp.934-940, 2023-11-22 (Released:2023-11-22)
- 参考文献数
- 34
Capturing atmospheric CO2 into cement-based materials is a way to set off the CO2 emissions of concrete production. This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured. The experimental results show that the 14C value of carbonated cement paste can be used as an indicator for tracing the origin of carbon.
- 著者
- Masayo Minami Akimasa Masuda
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.31, no.3, pp.125-133, 1997-06-20 (Released:2008-04-08)
- 参考文献数
- 20
- 被引用文献数
- 4 9
Here is presented a mathematical method which enables us to evaluate the degrees of lanthanide tetrad effects from the data involving all of REE. Each of the four spans corresponding to four subgroups, La-Nd, Pm-Gd, Gd-Ho, and Er-Lu, is approximately fitted to a quadratic function and the resultant quadratic coefficient is employed as a numerical indicator for the tetrad effect. For the purpose of approximation by a quadratic function, the least-squares method is used under the constraint that the first and second quadratic curves intersect at the middle point between Pm and Sm, and that the third and fourth ones intersect at the middle point between Ho and Er. Since, mathematically, the subject is a problem on the conditional extremum, the method of Lagrange undetermined multipliers should be used. It is noted that the degrees of four tetrad effects can be evaluated simultaneously. This method can lead us to the mathematically well-defined estimation of the tetrad effect.