Publications by authors named "T Yaita"
Article Synopsis
- A new in situ measurement technique for studying metal/metal-oxide mixtures at extreme temperatures (over 2000 K) was developed to enhance nuclear safety engineering.
- The researchers successfully conducted simultaneous XAFS-XRD measurements to track Zr oxidation and the ZrO-YO reaction over a range of temperatures (up to 2519 K), revealing significant chemical shifts.
- The study also explored the temperature effects on local structure dynamics, comparing experimental data with theoretical models, and proposed potential applications for analyzing nuclear fuel materials like UO-Zr.
Article Synopsis
- Different cations interact with clay minerals in contrasting ways, forming either outer-sphere or inner-sphere complexes, which significantly affects their environmental behaviors.
- This study is the first to investigate how radium (Ra) adsorbs onto clay minerals using EXAFS, revealing that Ra forms inner-sphere complexes on vermiculite despite its typical hydration preference.
- The research identified key factors influencing these complex formations, emphasizing the role of ionic radius and hydration enthalpy, and connected findings to environmental implications by analyzing core samples that show Ra's fixation by clay minerals.
Here, we investigated the mechanism underlying the extraction of Se(iv) and Se(vi) from aqueous HCl solutions by -2-ethylhexyl-bis(-di-2-ethylhexyl-ethylamide)amine (EHBAA). In addition to examining extraction behavior, we also elucidated structural properties of the dominant Se species in solution. Two types of aqueous HCl solutions were prepared by dissolving a Se oxide or a Se salt.
View Article and Find Full Text PDFThe solvent extraction of Sr(ii) was carried out using dicyclohexano-18-crown-6 (DCH18C6) and two HFC mixed solvents MS1 and MS2, where MS1 was composed of 30/60 (w/w)% -1,2-dichloroethylene/HFC-43 (HFC-43: 1,1,1,2,2,3,4,5,5,5-decafluoropentane) and MS2 was 5/95 (w/w)% heptane/HFC-43. Nitric acid and perfuruoro-3-6-9-trioxaundecane-1,11-dioic acid (HPFTOUD) were used to study the effect of acid on the extraction. The maximum distribution ratio of Sr(ii) ( ) observed for HPFTOUD conditions was ∼180, and >10 times larger than aqueous nitric acid conditions.
View Article and Find Full Text PDFArticle Synopsis
- The study examines radium from the perspective of both its environmental impact and its use in cancer therapy, focusing on its behavior as a hydrated ion.
- Using extended X-ray absorption fine structure (EXAFS) spectroscopy and advanced molecular dynamics (AIMD) simulations, researchers found specific coordination numbers and distances between radium ions and surrounding water molecules.
- The results indicate that radium's hydration structure is less ordered and more dynamic compared to barium, suggesting that radium has a higher lability, meaning it interacts more readily with water.